{"id":67703,"date":"2026-01-29T03:41:22","date_gmt":"2026-01-28T19:41:22","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/67703.html"},"modified":"2026-01-29T03:41:22","modified_gmt":"2026-01-28T19:41:22","slug":"linux-%e7%94%a8%e6%88%b7%e7%a9%ba%e9%97%b4%e4%b8%8e%e5%86%85%e6%a0%b8%e7%a9%ba%e9%97%b4%e7%9a%84-netlink-%e9%80%9a%e4%bf%a1%e6%9c%ba%e5%88%b6%e5%8f%8a%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/67703.html","title":{"rendered":"Linux \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u7684 Netlink \u901a\u4fe1\u673a\u5236\u53ca\u5b9e\u73b0"},"content":{"rendered":"

\u6ce8：\u672c\u6587\u4e3a \u201cLinux Netlink \u901a\u4fe1\u673a\u5236\u201d \u76f8\u5173\u5408\u8f91\u3002 \u7565\u4f5c\u91cd\u6392，\u672a\u6574\u7406\u53bb\u91cd\u3002 \u5982\u6709\u5185\u5bb9\u5f02\u5e38，\u8bf7\u770b\u539f\u6587\u3002<\/p>\n

\n

\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u901a\u4fe1\u2014\u2014Netlink（\u4e0a）<\/h2>\n

wjlkoorey258 2012-11-07 22:00:24<\/p>\n

\u5f15\u8a00<\/h3>\n

Alan Cox \u5728\u5185\u6838 1.3 \u7248\u672c\u7684\u5f00\u53d1\u9636\u6bb5\u9996\u6b21\u5f15\u5165\u4e86 Netlink \u673a\u5236，\u6700\u521d\u8be5\u673a\u5236\u4ee5\u5b57\u7b26\u9a71\u52a8\u63a5\u53e3\u7684\u5f62\u5f0f，\u63d0\u4f9b\u5185\u6838\u4e0e\u7528\u6237\u7a7a\u95f4\u4e4b\u95f4\u7684\u53cc\u5411\u6570\u636e\u901a\u4fe1\u80fd\u529b；\u968f\u540e，\u5728 2.1 \u5185\u6838\u7248\u672c\u7684\u5f00\u53d1\u8fc7\u7a0b\u4e2d，Alexey Kuznetsov \u5c06 Netlink \u91cd\u6784\u4e3a\u4e00\u5957\u66f4\u4e3a\u7075\u6d3b\u3001\u4e14\u6613\u4e8e\u6269\u5c55\u7684\u57fa\u4e8e\u6d88\u606f\u7684\u901a\u4fe1\u63a5\u53e3，\u5e76\u5c06\u5176\u5e94\u7528\u4e8e\u9ad8\u7ea7\u8def\u7531\u5b50\u7cfb\u7edf\u7684\u57fa\u7840\u6846\u67b6\u5b9e\u73b0\u4e2d\u3002\u81ea\u8be5\u9636\u6bb5\u8d77，Netlink \u4fbf\u6210\u4e3a Linux \u5185\u6838\u5b50\u7cfb\u7edf\u4e0e\u7528\u6237\u6001\u5e94\u7528\u7a0b\u5e8f\u4e4b\u95f4\u8fdb\u884c\u6570\u636e\u901a\u4fe1\u7684\u4e3b\u8981\u624b\u6bb5\u4e4b\u4e00\u3002<\/p>\n

2001 \u5e74，ForCES IETF \u59d4\u5458\u4f1a\u6b63\u5f0f\u542f\u52a8\u4e86 Netlink \u673a\u5236\u7684\u6807\u51c6\u5316\u5de5\u4f5c\u3002Jamal Hadi Salim \u63d0\u8bae\u5c06 Netlink \u5b9a\u4e49\u4e3a\u4e00\u79cd\u7528\u4e8e\u7f51\u7edc\u8bbe\u5907\u8def\u7531\u5f15\u64ce\u7ec4\u4ef6\u4e0e\u63a7\u5236\u7ba1\u7406\u7ec4\u4ef6\u4e4b\u95f4\u901a\u4fe1\u7684\u4e13\u7528\u534f\u8bae，\u4f46\u8be5\u63d0\u8bae\u6700\u7ec8\u672a\u88ab\u91c7\u7eb3\u3002\u53d6\u800c\u4ee3\u4e4b\u7684\u662f\u5f53\u524d\u7684\u5b9e\u73b0\u683c\u5c40：Netlink \u88ab\u8bbe\u8ba1\u4e3a\u4e00\u4e2a\u5168\u65b0\u7684\u534f\u8bae\u57df（domain）\u3002<\/p>\n

Linux \u521b\u59cb\u4eba Linus Torvalds \u66fe\u63d0\u51fa：\u201cLinux is evolution, not intelligent design\u201d\u3002\u8fd9\u4e00\u7406\u5ff5\u540c\u6837\u9002\u7528\u4e8e Netlink \u673a\u5236\u2014\u2014\u8be5\u673a\u5236\u4e0d\u5b58\u5728\u5b8c\u6574\u7684\u89c4\u8303\u6587\u6863\u4e0e\u8bbe\u8ba1\u6587\u6863，\u5176\u5e95\u5c42\u7ec6\u8282\u7684\u83b7\u53d6\u4ec5\u80fd\u901a\u8fc7\u201cRead the f**king source code\u201d\u7684\u65b9\u5f0f\u5b9e\u73b0\u3002<\/p>\n

\u672c\u6587\u4e0d\u6d89\u53ca Netlink \u5728 Linux \u7cfb\u7edf\u4e2d\u7684\u5b9e\u73b0\u673a\u5236\u5256\u6790，\u4ec5\u56f4\u7ed5\u201c\u4ec0\u4e48\u662f Netlink\u201d\u4e0e\u201c\u5982\u4f55\u6b63\u786e\u4f7f\u7528 Netlink\u201d\u4e24\u4e2a\u4e3b\u9898\u5c55\u5f00\u9610\u8ff0，\u4ec5\u5f53\u5b9e\u9645\u5e94\u7528\u4e2d\u9047\u5230\u95ee\u9898\u65f6，\u624d\u9700\u8981\u67e5\u9605\u5185\u6838\u6e90\u7801\u4ee5\u660e\u786e\u5176\u5e95\u5c42\u539f\u7406\u3002<\/p>\n

\u4ec0\u4e48\u662f Netlink<\/h3>\n

\u5bf9 Netlink \u673a\u5236\u7684\u7406\u89e3，\u9700\u628a\u63e1\u4ee5\u4e0b\u4e24\u4e2a\u5173\u952e\u8981\u70b9：<\/p>\n

  • \u9762\u5411\u6570\u636e\u62a5\u7684\u65e0\u8fde\u63a5\u6d88\u606f\u5b50\u7cfb\u7edf<\/li>\n
  • \u57fa\u4e8e\u901a\u7528 BSD Socket \u67b6\u6784\u5b9e\u73b0<\/li>\n

    \u5173\u4e8e\u7b2c\u4e00\u70b9，\u5176\u7279\u6027\u4e0e UDP \u534f\u8bae\u5177\u6709\u8f83\u9ad8\u7684\u76f8\u4f3c\u6027，\u4ee5 UDP \u534f\u8bae\u4e3a\u53c2\u8003\u7406\u89e3 Netlink \u673a\u5236\u5177\u6709\u5408\u7406\u6027\u3002\u901a\u8fc7\u77e5\u8bc6\u7684\u8fc1\u79fb\u3001\u5f52\u7eb3\u4e0e\u603b\u7ed3，\u53ef\u5b9e\u73b0\u5bf9\u8be5\u673a\u5236\u7684\u6df1\u5165\u638c\u63e1\u3002Netlink \u652f\u6301\u5185\u6838\u7a7a\u95f4\u5230\u7528\u6237\u7a7a\u95f4\u3001\u7528\u6237\u7a7a\u95f4\u5230\u5185\u6838\u7a7a\u95f4\u7684\u53cc\u5411\u5f02\u6b65\u6570\u636e\u901a\u4fe1，\u540c\u65f6\u4e5f\u652f\u6301\u4e24\u4e2a\u7528\u6237\u8fdb\u7a0b\u4e4b\u95f4\u3001\u4e24\u4e2a\u5185\u6838\u5b50\u7cfb\u7edf\u4e4b\u95f4\u7684\u6570\u636e\u901a\u4fe1\u3002\u672c\u6587\u4e0d\u6d89\u53ca\u540e\u4e24\u79cd\u901a\u4fe1\u573a\u666f，\u4ec5\u805a\u7126\u4e8e\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u4e4b\u95f4\u7684\u6570\u636e\u901a\u4fe1\u5b9e\u73b0\u3002<\/p>\n

    \u63d0\u53ca\u7b2c\u4e8c\u70b9，\u901a\u5e38\u4f1a\u8054\u60f3\u5230\u5bf9\u5e94\u7684 BSD Socket \u67b6\u6784\u793a\u610f\u56fe（\u5982\u4e0b\u6240\u793a）\u3002<\/p>\n

    \u5728\u540e\u7eed Netlink \u5957\u63a5\u5b57\u7f16\u7a0b\u7684\u5b9e\u6218\u73af\u8282\u4e2d，\u4e3b\u8981\u5c06\u4f7f\u7528 socket()\u3001bind()\u3001sendmsg() \u4e0e recvmsg() \u7b49\u7cfb\u7edf\u8c03\u7528，\u540c\u65f6\u8fd8\u4f1a\u7528\u5230 Socket \u63d0\u4f9b\u7684\u8f6e\u8be2（polling）\u673a\u5236\u3002<\/p>\n

    Netlink \u901a\u4fe1\u7c7b\u578b<\/h3>\n

    Netlink \u652f\u6301\u4e24\u79cd\u901a\u4fe1\u7c7b\u578b：\u5355\u64ad（Unicast）\u4e0e\u591a\u64ad（Multicast）\u3002<\/p>\n

    \u5355\u64ad<\/h4>\n

    \u5355\u64ad\u5e38\u7528\u4e8e\u5355\u4e2a\u7528\u6237\u8fdb\u7a0b\u4e0e\u5355\u4e2a\u5185\u6838\u5b50\u7cfb\u7edf\u4e4b\u95f4\u7684 <\/p>\n

    1 <\/p>\n

    : <\/p>\n

    1 <\/p>\n

    1:1 <\/p>\n

    <\/span><\/span>1<\/span><\/span>:<\/span><\/span><\/span><\/span>1<\/span><\/span><\/span><\/span><\/span> \u6570\u636e\u901a\u4fe1，\u7528\u6237\u7a7a\u95f4\u5411\u5185\u6838\u53d1\u9001\u547d\u4ee4，\u5e76\u63a5\u6536\u5185\u6838\u8fd4\u56de\u7684\u547d\u4ee4\u6267\u884c\u7ed3\u679c\u3002<\/p>\n

    \u591a\u64ad<\/h4>\n

    \u591a\u64ad\u5e38\u7528\u4e8e\u5355\u4e2a\u5185\u6838\u8fdb\u7a0b\u4e0e\u591a\u4e2a\u7528\u6237\u8fdb\u7a0b\u4e4b\u95f4\u7684 <\/p>\n

    1 <\/p>\n

    : <\/p>\n

    N <\/p>\n

    1:N <\/p>\n

    <\/span><\/span>1<\/span><\/span>:<\/span><\/span><\/span><\/span>N<\/span><\/span><\/span><\/span><\/span> \u6570\u636e\u901a\u4fe1，\u5185\u6838\u4f5c\u4e3a\u4f1a\u8bdd\u53d1\u8d77\u65b9，\u7528\u6237\u7a7a\u95f4\u5e94\u7528\u7a0b\u5e8f\u4f5c\u4e3a\u6d88\u606f\u63a5\u6536\u65b9\u3002\u5b9e\u73b0\u8be5\u529f\u80fd\u7684\u6d41\u7a0b\u4e3a：\u5185\u6838\u7a7a\u95f4\u7a0b\u5e8f\u521b\u5efa\u4e00\u4e2a\u591a\u64ad\u7ec4，\u6240\u6709\u5bf9\u8be5\u5185\u6838\u8fdb\u7a0b\u53d1\u9001\u7684\u6d88\u606f\u611f\u5174\u8da3\u7684\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b，\u5747\u53ef\u901a\u8fc7\u52a0\u5165\u8be5\u591a\u64ad\u7ec4\u7684\u65b9\u5f0f\u63a5\u6536\u5bf9\u5e94\u6d88\u606f\u3002<\/p>\n

    \u5176\u4e2d，\u8fdb\u7a0b A \u4e0e\u5b50\u7cfb\u7edf 1 \u4e4b\u95f4\u4e3a\u5355\u64ad\u901a\u4fe1，\u8fdb\u7a0b B\u3001C \u4e0e\u5b50\u7cfb\u7edf 2 \u4e4b\u95f4\u4e3a\u591a\u64ad\u901a\u4fe1\u3002\u4e0a\u8ff0\u793a\u610f\u56fe\u8fd8\u63ed\u793a\u4e86\u4e00\u4e2a\u91cd\u8981\u7279\u6027：\u4ece\u7528\u6237\u7a7a\u95f4\u4f20\u9012\u81f3\u5185\u6838\u7a7a\u95f4\u7684\u6570\u636e\u65e0\u9700\u6392\u961f，\u5bf9\u5e94\u7684\u64cd\u4f5c\u4ee5\u540c\u6b65\u65b9\u5f0f\u5b8c\u6210；\u800c\u4ece\u5185\u6838\u7a7a\u95f4\u4f20\u9012\u81f3\u7528\u6237\u7a7a\u95f4\u7684\u6570\u636e\u9700\u8981\u6392\u961f，\u5bf9\u5e94\u7684\u64cd\u4f5c\u4ee5\u5f02\u6b65\u65b9\u5f0f\u5b8c\u6210\u3002\u638c\u63e1\u8be5\u7279\u6027\u80fd\u591f\u5728\u57fa\u4e8e Netlink \u5f00\u53d1\u5e94\u7528\u6a21\u5757\u65f6\u89c4\u907f\u8bf8\u591a\u6f5c\u5728\u95ee\u9898\u3002\u4f8b\u5982，\u5f53\u7528\u6237\u7a7a\u95f4\u5411\u5185\u6838\u53d1\u9001\u6d88\u606f\u4ee5\u83b7\u53d6\u8def\u7531\u8868\u7b49\u5927\u89c4\u6a21\u6570\u636e\u65f6，\u5185\u6838\u901a\u8fc7 Netlink \u8fd4\u56de\u6570\u636e\u7684\u8fc7\u7a0b\u4e2d，\u5f00\u53d1\u4eba\u5458\u9700\u91cd\u70b9\u8003\u8651\u6570\u636e\u7684\u63a5\u6536\u7b56\u7565，\u5145\u5206\u91cd\u89c6\u5185\u6838\u7a7a\u95f4\u7684\u8f93\u51fa\u961f\u5217\u7279\u6027\u3002<\/p>\n

    Netlink \u7684\u6d88\u606f\u683c\u5f0f<\/h3>\n

    Netlink \u6d88\u606f\u7531\u6d88\u606f\u5934（Message Header）\u4e0e\u6709\u6548\u6570\u636e\u8f7d\u8377（Payload）\u4e24\u90e8\u5206\u7ec4\u6210，\u6574\u4e2a Netlink \u6d88\u606f\u9700\u6ee1\u8db3 <\/p>\n

    4 <\/p>\n

    4 <\/p>\n

    <\/span><\/span>4<\/span><\/span><\/span><\/span><\/span> \u5b57\u8282\u5bf9\u9f50\u8981\u6c42，\u901a\u5e38\u4ee5\u4e3b\u673a\u5b57\u8282\u5e8f\u8fdb\u884c\u4f20\u9012\u3002\u6d88\u606f\u5934\u4e3a\u56fa\u5b9a <\/p>\n

    16 <\/p>\n

    16 <\/p>\n

    <\/span><\/span>16<\/span><\/span><\/span><\/span><\/span> \u5b57\u8282\u957f\u5ea6，\u6d88\u606f\u4f53\u957f\u5ea6\u4e3a\u53ef\u53d8\u503c\u3002<\/p>\n

    Netlink \u7684\u6d88\u606f\u5934<\/h4>\n

    \u6d88\u606f\u5934\u5b9a\u4e49\u5728\u5bf9\u5e94\u5185\u6838\u5934\u6587\u4ef6\u4e2d，\u7531\u7ed3\u6784\u4f53 struct nlmsghdr \u8868\u793a，\u5176\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

    struct<\/span> nlmsghdr<\/span>
    \n{<\/span>
    \n __u32 nlmsg_len;<\/span> \/* Length of message including header *\/<\/span>
    \n __u16 nlmsg_type;<\/span> \/* Message content *\/<\/span>
    \n __u16 nlmsg_flags;<\/span> \/* Additional flags *\/<\/span>
    \n __u32 nlmsg_seq;<\/span> \/* Sequence number *\/<\/span>
    \n __u32 nlmsg_pid;<\/span> \/* Sending process PID *\/<\/span>
    \n}<\/span>;<\/span><\/p>\n

    \u6d88\u606f\u5934\u4e2d\u5404\u6210\u5458\u7684\u5c5e\u6027\u89e3\u91ca\u5982\u4e0b：<\/p>\n

  • nlmsg_len：\u6574\u4e2a\u6d88\u606f\u7684\u5b57\u8282\u957f\u5ea6，\u5305\u542b Netlink \u6d88\u606f\u5934\u672c\u8eab\u7684\u957f\u5ea6\u3002<\/li>\n
  • nlmsg_type：\u6d88\u606f\u7c7b\u578b，\u7528\u4e8e\u533a\u5206\u6570\u636e\u6d88\u606f\u4e0e\u63a7\u5236\u6d88\u606f\u3002\u5728\u5185\u6838 2.6.21 \u7248\u672c\u4e2d，Netlink \u4ec5\u652f\u6301\u56db\u79cd\u63a7\u5236\u6d88\u606f，\u5177\u4f53\u5982\u4e0b：\n
      \n
    • NLMSG_NOOP：\u7a7a\u6d88\u606f，\u65e0\u4efb\u4f55\u5b9e\u9645\u64cd\u4f5c；<\/li>\n
    • NLMSG_ERROR：\u6807\u8bc6\u8be5\u6d88\u606f\u4e2d\u5305\u542b\u9519\u8bef\u4fe1\u606f；<\/li>\n
    • NLMSG_DONE：\u5f53\u5185\u6838\u901a\u8fc7 Netlink \u961f\u5217\u8fd4\u56de\u591a\u6761\u6d88\u606f\u65f6，\u961f\u5217\u7684\u6700\u540e\u4e00\u6761\u6d88\u606f\u7c7b\u578b\u4e3a\u6b64\u503c，\u5176\u4f59\u6240\u6709\u6d88\u606f\u7684 nlmsg_flags \u5c5e\u6027\u5747\u4f1a\u8bbe\u7f6e NLM_F_MULTI \u4f4d\u6709\u6548；<\/li>\n
    • NLMSG_OVERRUN：\u6682\u672a\u542f\u7528\u3002<\/li>\n<\/ul>\n<\/li>\n
    • nlmsg_flags：\u9644\u52a0\u5728\u6d88\u606f\u4e0a\u7684\u989d\u5916\u8bf4\u660e\u4fe1\u606f，\u4f8b\u5982\u524d\u6587\u63d0\u53ca\u7684 NLM_F_MULTI\u3002\u90e8\u5206\u5e38\u7528\u6807\u8bb0\u53ca\u5176\u4f5c\u7528\u5982\u4e0b\u8868\u6240\u793a：<\/li>\n\n\u6807\u8bb0\u4f5c\u7528\u53ca\u8bf4\u660e<\/tr>\n\n\n\n\n\n\n
      NLM_F_REQUEST<\/td>\n\u82e5\u6d88\u606f\u5305\u542b\u8be5\u6807\u8bb0\u4f4d，\u8868\u660e\u8be5\u6d88\u606f\u4e3a\u8bf7\u6c42\u6d88\u606f\u3002\u6240\u6709\u4ece\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u81f3\u5185\u6838\u7a7a\u95f4\u7684\u6d88\u606f\u5747\u9700\u8bbe\u7f6e\u8be5\u4f4d，\u5426\u5219\u5185\u6838\u5c06\u5411\u7528\u6237\u7a7a\u95f4\u8fd4\u56de EINVAL \u65e0\u6548\u53c2\u6570\u9519\u8bef<\/td>\n<\/tr>\n
      NLM_F_MULTI<\/td>\n\u7528\u6237\u7a7a\u95f4\u81f3\u5185\u6838\u7a7a\u95f4\u7684\u6d88\u606f\u4f20\u8f93\u4e3a\u540c\u6b65\u5373\u65f6\u5b8c\u6210，\u800c\u5185\u6838\u7a7a\u95f4\u81f3\u7528\u6237\u7a7a\u95f4\u7684\u6d88\u606f\u4f20\u8f93\u9700\u8981\u6392\u961f\u3002\u82e5\u5185\u6838\u6536\u5230\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u7684\u5305\u542b NLM_F_DUMP \u4f4d\u4e3a <\/p>\n

      1 <\/p>\n

      1 <\/p>\n

      <\/span><\/span>1<\/span><\/span><\/span><\/span><\/span> \u7684\u6d88\u606f，\u5c06\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u4e00\u4e2a\u7531\u591a\u6761 Netlink \u6d88\u606f\u7ec4\u6210\u7684\u94fe\u8868\u3002\u9664\u6700\u540e\u4e00\u6761\u6d88\u606f\u5916，\u5176\u4f59\u6bcf\u6761\u6d88\u606f\u5747\u4f1a\u8bbe\u7f6e\u8be5\u4f4d\u6709\u6548<\/td>\n<\/tr>\n

      NLM_F_ACK<\/td>\n\u8be5\u6d88\u606f\u662f\u5185\u6838\u5bf9\u6765\u81ea\u7528\u6237\u7a7a\u95f4\u7684 NLM_F_REQUEST \u6d88\u606f\u7684\u54cd\u5e94\u6d88\u606f<\/td>\n<\/tr>\n
      NLM_F_ECHO<\/td>\n\u82e5\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u81f3\u5185\u6838\u7684\u6d88\u606f\u4e2d\u8be5\u6807\u8bb0\u4e3a <\/p>\n

      1 <\/p>\n

      1 <\/p>\n

      <\/span><\/span>1<\/span><\/span><\/span><\/span><\/span>，\u8868\u660e\u7528\u6237\u5e94\u7528\u8fdb\u7a0b\u8981\u6c42\u5185\u6838\u5c06\u8be5\u6d88\u606f\u901a\u8fc7\u5355\u64ad\u5f62\u5f0f\u56de\u4f20\u7ed9\u8be5\u7528\u6237\u8fdb\u7a0b，\u4e0e\u5e38\u89c4\u7684\u201c\u56de\u663e\u201d\u529f\u80fd\u7c7b\u4f3c<\/td>\n<\/tr>\n

      \u2026<\/td>\n\u2026<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \u5173\u4e8e nlmsg_flags \u7684\u5b8c\u6574\u53d6\u503c，\u53ef\u901a\u8fc7\u67e5\u9605\u5185\u6838\u6e90\u7801\u4e0e\u5b98\u65b9\u6280\u672f\u6587\u6863\u83b7\u53d6，\u6b64\u5904\u4e0d\u505a\u8fdb\u4e00\u6b65\u5c55\u5f00\u3002<\/p>\n

    • \n

      nlmsg_seq：\u6d88\u606f\u5e8f\u5217\u53f7\u3002\u7531\u4e8e Netlink \u662f\u9762\u5411\u6570\u636e\u62a5\u7684\u901a\u4fe1\u673a\u5236，\u5b58\u5728\u6570\u636e\u4e22\u5931\u7684\u6f5c\u5728\u98ce\u9669，\u800c Netlink \u63d0\u4f9b\u4e86\u6d88\u606f\u53ef\u9760\u6027\u4fdd\u969c\u7684\u57fa\u7840\u673a\u5236，\u53ef\u4f9b\u7a0b\u5e8f\u5f00\u53d1\u4eba\u5458\u6839\u636e\u5b9e\u9645\u9700\u6c42\u8fdb\u884c\u5b9e\u73b0\u3002\u6d88\u606f\u5e8f\u5217\u53f7\u901a\u5e38\u4e0e NLMSG_ACK \u7c7b\u578b\u6d88\u606f\u8054\u5408\u4f7f\u7528，\u82e5\u7528\u6237\u5e94\u7528\u7a0b\u5e8f\u9700\u8981\u786e\u4fdd\u53d1\u9001\u7684\u6bcf\u6761\u6d88\u606f\u5747\u88ab\u5185\u6838\u6210\u529f\u63a5\u6536，\u53d1\u9001\u6d88\u606f\u65f6\u9700\u81ea\u884c\u8bbe\u7f6e\u8be5\u5e8f\u5217\u53f7，\u5185\u6838\u6536\u5230\u6d88\u606f\u540e\u63d0\u53d6\u8be5\u5e8f\u5217\u53f7，\u5e76\u5728\u54cd\u5e94\u6d88\u606f\u4e2d\u8bbe\u7f6e\u76f8\u540c\u7684\u5e8f\u5217\u53f7，\u8be5\u673a\u5236\u4e0e TCP \u534f\u8bae\u7684\u5e94\u7b54\u786e\u8ba4\u673a\u5236\u5177\u6709\u76f8\u4f3c\u6027\u3002<\/p>\n

      \u6ce8\u610f：\u5f53\u5185\u6838\u4e3b\u52a8\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u5e7f\u64ad\u6d88\u606f\u65f6，\u8be5\u5b57\u6bb5\u7684\u503c\u6052\u4e3a <\/p>\n

      0 <\/p>\n

      0 <\/p>\n

      <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>\u3002<\/p>\n<\/li>\n

    • \n

      nlmsg_pid：\u5f53\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u4e0e\u5185\u6838\u7a7a\u95f4\u5b50\u7cfb\u7edf\u901a\u8fc7 Netlink \u5efa\u7acb\u6570\u636e\u4ea4\u6362\u901a\u9053\u540e，Netlink \u4f1a\u4e3a\u6bcf\u4e2a\u901a\u9053\u5206\u914d\u552f\u4e00\u7684\u6570\u5b57\u6807\u8bc6，\u8be5\u5b57\u6bb5\u7684\u4f5c\u7528\u662f\u5c06\u7528\u6237\u7a7a\u95f4\u7684\u8bf7\u6c42\u6d88\u606f\u4e0e\u5185\u6838\u7684\u54cd\u5e94\u6d88\u606f\u8fdb\u884c\u5173\u8054，\u786e\u4fdd\u591a\u7ec4\u201c\u7528\u6237-\u5185\u6838\u201d\u901a\u4fe1\u8fdb\u7a0b\u4e4b\u95f4\u7684\u6570\u636e\u4ea4\u4e92\u4e0d\u4f1a\u51fa\u73b0\u7d0a\u4e71\u3002\u4f8b\u5982，\u5f53\u8fdb\u7a0b A\u3001B \u540c\u65f6\u901a\u8fc7 Netlink \u5411\u5b50\u7cfb\u7edf 1 \u83b7\u53d6\u4fe1\u606f\u65f6，\u5b50\u7cfb\u7edf 1 \u9700\u786e\u4fdd\u56de\u4f20\u7ed9\u8fdb\u7a0b A \u7684\u54cd\u5e94\u6570\u636e\u4e0d\u4f1a\u53d1\u9001\u81f3\u8fdb\u7a0b B\u3002\u8be5\u5b57\u6bb5\u901a\u5e38\u9002\u7528\u4e8e\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u4ece\u5185\u6838\u7a7a\u95f4\u83b7\u53d6\u6570\u636e\u7684\u573a\u666f，\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5411\u5185\u6838\u53d1\u9001\u6d88\u606f\u65f6，\u4e00\u822c\u901a\u8fc7 getpid() \u7cfb\u7edf\u8c03\u7528\u5c06\u5f53\u524d\u8fdb\u7a0b\u7684\u8fdb\u7a0b\u53f7\u8d4b\u503c\u7ed9\u8be5\u5b57\u6bb5（\u4ec5\u5f53\u9700\u8981\u83b7\u53d6\u5185\u6838\u54cd\u5e94\u65f6\u8fdb\u884c\u8be5\u64cd\u4f5c）\u3002\u5185\u6838\u4e3b\u52a8\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6d88\u606f\u65f6，\u8be5\u5b57\u6bb5\u7684\u503c\u6052\u4e3a <\/p>\n

      0 <\/p>\n

      0 <\/p>\n

      <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>\u3002<\/p>\n<\/li>\n

      Netlink \u7684\u6d88\u606f\u4f53<\/h4>\n

      Netlink \u7684\u6d88\u606f\u4f53\u91c7\u7528 TLV（Type-Length-Value）\u683c\u5f0f\u8fdb\u884c\u7ec4\u7ec7，\u6bcf\u4e2a\u5c5e\u6027\u5747\u7531\u5934\u6587\u4ef6\u4e2d\u7684 struct nlattr{} \u7ed3\u6784\u4f53\u8868\u793a\u3002<\/p>\n

      Netlink \u63d0\u4f9b\u7684\u9519\u8bef\u6307\u793a\u6d88\u606f<\/h4>\n

      \u5f53\u7528\u6237\u7a7a\u95f4\u5e94\u7528\u7a0b\u5e8f\u4e0e\u5185\u6838\u7a7a\u95f4\u8fdb\u7a0b\u901a\u8fc7 Netlink \u901a\u4fe1\u53d1\u751f\u9519\u8bef\u65f6，Netlink \u4f1a\u5411\u7528\u6237\u7a7a\u95f4\u901a\u62a5\u8be5\u9519\u8bef\u4fe1\u606f，\u9519\u8bef\u6d88\u606f\u91c7\u7528\u5355\u72ec\u5c01\u88c5\u7684\u5f62\u5f0f，\u5bf9\u5e94\u7684\u7ed3\u6784\u4f53 struct nlmsgerr \u5b9a\u4e49\u5982\u4e0b：<\/p>\n

      struct<\/span> nlmsgerr<\/span>
      \n{<\/span>
      \n int<\/span> error;<\/span> \/\/ \u6807\u51c6\u9519\u8bef\u7801，\u5b9a\u4e49\u5728 errno.h \u5934\u6587\u4ef6\u4e2d，\u53ef\u901a\u8fc7 perror() \u51fd\u6570\u89e3\u6790<\/span>
      \n struct<\/span> nlmsghdr<\/span> msg;<\/span> \/\/ \u6307\u660e\u89e6\u53d1\u8be5\u9519\u8bef\u7684\u539f\u59cb\u6d88\u606f<\/span>
      \n}<\/span>;<\/span><\/p>\n

      Netlink \u7f16\u7a0b\u9700\u8981\u6ce8\u610f\u7684\u95ee\u9898<\/h3>\n

      \u57fa\u4e8e Netlink \u5b9e\u73b0\u7684\u7528\u6237-\u5185\u6838\u7a7a\u95f4\u901a\u4fe1，\u5b58\u5728\u4e24\u79cd\u53ef\u80fd\u5bfc\u81f4\u4e22\u5305\u7684\u573a\u666f：<\/p>\n

    • \u7cfb\u7edf\u5185\u5b58\u8017\u5c3d；<\/li>\n
    • \u7528\u6237\u7a7a\u95f4\u63a5\u6536\u8fdb\u7a0b\u7684\u7f13\u51b2\u533a\u6ea2\u51fa\u3002\u7f13\u51b2\u533a\u6ea2\u51fa\u7684\u4e3b\u8981\u8bf1\u56e0\u5305\u62ec：\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u8fd0\u884c\u6548\u7387\u8fc7\u4f4e，\u6216\u63a5\u6536\u961f\u5217\u957f\u5ea6\u8fc7\u77ed\u3002<\/li>\n

      \u82e5 Netlink \u65e0\u6cd5\u5c06\u6d88\u606f\u6b63\u786e\u4f20\u9012\u81f3\u7528\u6237\u7a7a\u95f4\u63a5\u6536\u8fdb\u7a0b，\u7528\u6237\u7a7a\u95f4\u63a5\u6536\u8fdb\u7a0b\u8c03\u7528 recvmsg() \u7cfb\u7edf\u8c03\u7528\u65f6，\u5c06\u8fd4\u56de ENOBUFS（\u5185\u5b58\u4e0d\u8db3）\u9519\u8bef，\u8be5\u7279\u6027\u9700\u91cd\u70b9\u5173\u6ce8\u3002\u6362\u53e5\u8bdd\u8bf4，\u7f13\u51b2\u533a\u6ea2\u51fa\u95ee\u9898\u4e0d\u4f1a\u51fa\u73b0\u5728\u4ece\u7528\u6237\u7a7a\u95f4\u5230\u5185\u6838\u7a7a\u95f4\u7684 sendmsg() \u7cfb\u7edf\u8c03\u7528\u8fc7\u7a0b\u4e2d，\u5176\u539f\u56e0\u524d\u6587\u5df2\u8fdb\u884c\u9610\u8ff0，\u53ef\u81ea\u884c\u8fdb\u884c\u68b3\u7406\u603b\u7ed3\u3002<\/p>\n

      \u6b64\u5916，\u82e5\u4f7f\u7528\u963b\u585e\u578b Socket \u8fdb\u884c\u901a\u4fe1，\u5219\u4e0d\u5b58\u5728\u5185\u5b58\u8017\u5c3d\u7684\u6f5c\u5728\u98ce\u9669，\u76f8\u5173\u539f\u7406\u53ef\u901a\u8fc7\u67e5\u9605\u963b\u585e\u578b Socket \u7684\u5b98\u65b9\u6280\u672f\u6587\u6863\u8fdb\u884c\u6df1\u5165\u7406\u89e3\u3002<\/p>\n

      Netlink \u7684\u5730\u5740\u7ed3\u6784\u4f53<\/h3>\n

      \u5728 TCP \u7f16\u7a0b\u76f8\u5173\u5185\u5bb9\u4e2d，\u66fe\u63d0\u53ca Internet \u7f16\u7a0b\u8fc7\u7a0b\u4e2d\u4f7f\u7528\u7684\u5730\u5740\u7ed3\u6784\u4f53\u4e0e\u6807\u51c6\u5730\u5740\u7ed3\u6784\u4f53，\u8fd9\u4e9b\u7ed3\u6784\u4f53\u4e0e Netlink \u5730\u5740\u7ed3\u6784\u4f53\u5b58\u5728\u5bf9\u5e94\u5173\u8054\u3002<\/p>\n

      Netlink \u5bf9\u5e94\u7684\u5730\u5740\u7ed3\u6784\u4f53 struct sockaddr_nl{} \u8be6\u7ec6\u5b9a\u4e49\u4e0e\u63cf\u8ff0\u5982\u4e0b：<\/p>\n

      struct<\/span> sockaddr_nl<\/span>
      \n{<\/span>
      \n sa_family_t<\/span> nl_family;<\/span> \/* \u8be5\u5b57\u6bb5\u6052\u4e3a AF_NETLINK *\/<\/span>
      \n unsigned<\/span> short<\/span> nl_pad;<\/span> \/* \u76ee\u524d\u672a\u542f\u7528，\u586b\u5145\u4e3a 0 *\/<\/span>
      \n __u32 nl_pid;<\/span> \/* process pid *\/<\/span>
      \n __u32 nl_groups;<\/span> \/* multicast groups mask *\/<\/span>
      \n}<\/span>;<\/span><\/p>\n

    • \n

      nl_pid：\u8be5\u5c5e\u6027\u4e3a\u53d1\u9001\u6216\u63a5\u6536\u6d88\u606f\u7684\u8fdb\u7a0b ID\u3002\u524d\u6587\u63d0\u53ca，Netlink \u4e0d\u4ec5\u652f\u6301\u7528\u6237-\u5185\u6838\u7a7a\u95f4\u4e4b\u95f4\u7684\u901a\u4fe1，\u8fd8\u652f\u6301\u7528\u6237\u7a7a\u95f4\u4e24\u4e2a\u8fdb\u7a0b\u4e4b\u95f4\u3001\u5185\u6838\u7a7a\u95f4\u4e24\u4e2a\u8fdb\u7a0b\u4e4b\u95f4\u7684\u901a\u4fe1\u3002\u8be5\u5c5e\u6027\u503c\u4e3a <\/p>\n

      0 <\/p>\n

      0 <\/p>\n

      <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span> \u65f6，\u901a\u5e38\u9002\u7528\u4e8e\u4ee5\u4e0b\u4e24\u79cd\u573a\u666f：<\/p>\n

        \n
      • \u573a\u666f\u4e00：\u6d88\u606f\u7684\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4（\u5373\u4ece\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6d88\u606f\u81f3\u5185\u6838\u7a7a\u95f4），\u6b64\u65f6\u6784\u9020\u7684 Netlink \u5730\u5740\u7ed3\u6784\u4f53\u4e2d，nl_pid \u5b57\u6bb5\u901a\u5e38\u7f6e\u4e3a \n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>\u3002\u9700\u8981\u8865\u5145\u8bf4\u660e\u7684\u662f，\u5728 Netlink \u89c4\u8303\u4e2d，PID \u7684\u5168\u79f0\u4e3a Port-ID（ <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> bits），\u5176\u4f5c\u7528\u662f\u552f\u4e00\u6807\u8bc6\u4e00\u4e2a\u57fa\u4e8e Netlink \u7684 Socket \u901a\u9053\u3002\u901a\u5e38\u60c5\u51b5\u4e0b，nl_pid \u5b57\u6bb5\u4f1a\u88ab\u8bbe\u7f6e\u4e3a\u5f53\u524d\u8fdb\u7a0b\u7684\u8fdb\u7a0b\u53f7；\u4f46\u5f53\u4e00\u4e2a\u8fdb\u7a0b\u7684\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u4f7f\u7528 Netlink Socket \u65f6，nl_pid \u5b57\u6bb5\u901a\u5e38\u91c7\u7528\u5982\u4e0b\u65b9\u5f0f\u8fdb\u884c\u8bbe\u7f6e：pthread_self<\/span>(<\/span>)<\/span> <<<\/span> 16<\/span> |<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span>\n <\/li>\n

      • \u573a\u666f\u4e8c：\u5185\u6838\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u591a\u64ad\u62a5\u6587\u65f6，\u82e5\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5df2\u52a0\u5165\u5bf9\u5e94\u591a\u64ad\u7ec4，\u5176\u5730\u5740\u7ed3\u6784\u4f53\u4e2d\u7684 nl_pid \u5b57\u6bb5\u540c\u6837\u7f6e\u4e3a \n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>，\u540c\u65f6\u9700\u7ed3\u5408\u4e0b\u8ff0 nl_groups \u5b57\u6bb5\u8fdb\u884c\u914d\u7f6e\u3002<\/li>\n<\/ul>\n<\/li>\n

      • \n

        nl_groups：\u82e5\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5e0c\u671b\u52a0\u5165\u67d0\u4e2a\u591a\u64ad\u7ec4，\u5fc5\u987b\u6267\u884c bind() \u7cfb\u7edf\u8c03\u7528\u3002\u8be5\u5b57\u6bb5\u6307\u660e\u4e86\u8c03\u7528\u8005\u5e0c\u671b\u52a0\u5165\u7684\u591a\u64ad\u7ec4\u53f7\u7684\u63a9\u7801（\u6ce8\u610f：\u5e76\u975e\u7ec4\u53f7，\u5176\u8be6\u7ec6\u7528\u6cd5\u5c06\u5728\u540e\u7eed\u5185\u5bb9\u4e2d\u9610\u8ff0）\u3002\u82e5\u8be5\u5b57\u6bb5\u503c\u4e3a <\/p>\n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>，\u8868\u660e\u8c03\u7528\u8005\u4e0d\u5e0c\u671b\u52a0\u5165\u4efb\u4f55\u591a\u64ad\u7ec4\u3002\u5bf9\u4e8e\u6bcf\u4e2a\u96b6\u5c5e\u4e8e Netlink \u534f\u8bae\u57df\u7684\u534f\u8bae，\u6700\u591a\u652f\u6301 <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u4e2a\u591a\u64ad\u7ec4（\u56e0 nl_groups \u5b57\u6bb5\u957f\u5ea6\u4e3a <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u6bd4\u7279），\u6bcf\u4e2a\u591a\u64ad\u7ec4\u7531\u4e00\u4e2a\u72ec\u7acb\u7684\u6bd4\u7279\u4f4d\u8868\u793a\u3002<\/p>\n<\/li>\n

        \u5173\u4e8e Netlink \u7684\u5176\u4f59\u77e5\u8bc6\u70b9，\u5c06\u5728\u540e\u7eed\u5b9e\u6218\u73af\u8282\u4e2d\u7ed3\u5408\u5177\u4f53\u5e94\u7528\u573a\u666f\u8fdb\u884c\u9610\u8ff0\u3002<\/p>\n

        \n

        \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u901a\u4fe1\u2014\u2014Netlink（\u4e2d）<\/h2>\n

        wjlkoorey258 2012-11-12 19:42:22<\/p>\n

        \u672c\u8282\u5c06\u901a\u8fc7\u5b9e\u9645\u7f16\u7a0b\u6f14\u7ec3，\u5c55\u793a Netlink \u673a\u5236\u5982\u4f55\u5b9e\u73b0\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u4e4b\u95f4\u7684\u6570\u636e\u901a\u4fe1，\u6240\u6709\u5b9e\u9a8c\u5747\u57fa\u4e8e\u5185\u6838 2.6.21 \u7248\u672c\u73af\u5883\u5b8c\u6210\u3002<\/p>\n

        \u5bf9\u5e94\u7684\u5185\u6838\u5934\u6587\u4ef6\u4e2d\u5305\u542b\u4e86 Netlink \u534f\u8bae\u7c07\u9884\u5b9a\u4e49\u7684\u5404\u7c7b\u534f\u8bae，\u5177\u4f53\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

        #<\/span>define<\/span> NETLINK_ROUTE<\/span> 0<\/span> <\/span>\/* Routing\/device hook *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_UNUSED<\/span> 1<\/span> <\/span>\/* Unused number *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_USERSOCK<\/span> 2<\/span> <\/span>\/* Reserved for user mode socket protocols *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIREWALL<\/span> 3<\/span> <\/span>\/* Firewalling hook *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_INET_DIAG<\/span> 4<\/span> <\/span>\/* INET socket monitoring *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NFLOG<\/span> 5<\/span> <\/span>\/* netfilter\/iptables ULOG *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_XFRM<\/span> 6<\/span> <\/span>\/* ipsec *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_SELINUX<\/span> 7<\/span> <\/span>\/* SELinux event notifications *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_ISCSI<\/span> 8<\/span> <\/span>\/* Open-iSCSI *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_AUDIT<\/span> 9<\/span> <\/span>\/* auditing *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIB_LOOKUP<\/span> 10<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_CONNECTOR<\/span> 11<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NETFILTER<\/span> 12<\/span> <\/span>\/* netfilter subsystem *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_IP6_FW<\/span> 13<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_DNRTMSG<\/span> 14<\/span> <\/span>\/* DECnet routing messages *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_KOBJECT_UEVENT<\/span> 15<\/span> <\/span>\/* Kernel messages to userspace *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_GENERIC<\/span> 16<\/span><\/span><\/span>
        \n\/* leave room for NETLINK_DM (DM Events) *\/<\/span>
        \n#<\/span>define<\/span> NETLINK_SCSITRANSPORT<\/span> 18<\/span> <\/span>\/* SCSI Transports *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_ECRYPTFS<\/span> 19<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_TEST<\/span> 20<\/span> <\/span>\/* \u7528\u6237\u6dfb\u52a0\u7684\u81ea\u5b9a\u4e49\u534f\u8bae *\/<\/span><\/span><\/p>\n

        \u82e5\u9700\u5728 Netlink \u534f\u8bae\u7c07\u4e2d\u5f00\u53d1\u81ea\u5b9a\u4e49\u534f\u8bae，\u4ec5\u9700\u5728\u8be5\u6587\u4ef6\u4e2d\u5b9a\u4e49\u5bf9\u5e94\u7684\u534f\u8bae\u53f7\u5373\u53ef，\u4f8b\u5982\u4e0a\u8ff0\u4ee3\u7801\u4e2d\u5b9a\u4e49\u7684\u534f\u8bae\u53f7\u4e3a <\/p>\n

        20 <\/p>\n

        20 <\/p>\n

        <\/span><\/span>20<\/span><\/span><\/span><\/span><\/span> \u7684\u81ea\u5b9a\u4e49\u534f\u8bae NETLINK_TEST\u3002\u540c\u65f6，\u9700\u8981\u5bf9\u5185\u6838\u5934\u6587\u4ef6\u76ee\u5f55\u4e2d\u7684 netlink.h \u8fdb\u884c\u5bf9\u5e94\u7684\u4fee\u6539，\u5728\u672c\u6b21\u5b9e\u9a8c\u73af\u5883\u4e2d，\u8be5\u6587\u4ef6\u7684\u8def\u5f84\u4e3a：\/usr\/src\/linux-2.6.21\/include\/linux\/netlink.h\u3002<\/p>\n

        \u5b8c\u6210\u4e0a\u8ff0\u914d\u7f6e\u540e，\u5373\u53ef\u5728\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u6a21\u5757\u7684\u5f00\u53d1\u8fc7\u7a0b\u4e2d\u4f7f\u7528\u8be5\u81ea\u5b9a\u4e49\u534f\u8bae，\u6574\u4e2a\u5b9e\u9a8c\u5206\u4e3a\u4e09\u4e2a\u9636\u6bb5\u8fdb\u884c\u3002<\/p>\n

        Stage 1：\u7528\u6237->\u5185\u6838\u5355\u5411\u6570\u636e\u901a\u4fe1<\/h3>\n

        \u672c\u9636\u6bb5\u5b9e\u73b0\u7684\u529f\u80fd\u4e3a\u7528\u6237\u7a7a\u95f4\u5230\u5185\u6838\u7a7a\u95f4\u7684\u5355\u5411\u6570\u636e\u901a\u4fe1，\u5373\u7528\u6237\u7a7a\u95f4\u5411\u5185\u6838\u53d1\u9001\u4e00\u6761\u6d88\u606f，\u5185\u6838\u63a5\u6536\u8be5\u6d88\u606f\u5e76\u5c06\u5176\u6253\u5370\u8f93\u51fa，\u5177\u4f53\u5b9e\u73b0\u5982\u4e0b\u3002<\/p>\n

        \u7528\u6237\u7a7a\u95f4\u793a\u4f8b\u4ee3\u7801\u3010mynlusr.c\u3011<\/h4>\n

        #<\/span>include<\/span> <sys\/stat.h><\/span><\/span>
        \n#<\/span>include<\/span> <unistd.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdio.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdlib.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/socket.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <string.h><\/span><\/span>
        \n#<\/span>include<\/span> <asm\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/socket.h><\/span><\/span><\/p>\n

        #<\/span>define<\/span> MAX_PAYLOAD<\/span> 1024<\/span> <\/span>\/* \u6d88\u606f\u6700\u5927\u8d1f\u8f7d\u4e3a 1024 \u5b57\u8282 *\/<\/span><\/span><\/p>\n

        int<\/span> main<\/span>(<\/span>int<\/span> argc,<\/span> char<\/span>*<\/span> argv[<\/span>]<\/span>)<\/span>
        \n{<\/span>
        \n struct<\/span> sockaddr_nl<\/span> dest_addr;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
        \n struct<\/span> iovec<\/span> iov;<\/span>
        \n int<\/span> sock_fd=<\/span>–<\/span>1<\/span>;<\/span>
        \n struct<\/span> msghdr<\/span> msg;<\/span><\/p>\n

        \/\/ \u521b\u5efa\u5957\u63a5\u5b57<\/span>
        \n if<\/span>(<\/span>–<\/span>1<\/span> ==<\/span> (<\/span>sock_fd=<\/span>socket<\/span>(<\/span>PF_NETLINK,<\/span> SOCK_RAW,<\/span>NETLINK_TEST)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"can't create netlink socket!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span>
        \n memset<\/span>(<\/span>&<\/span>dest_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span>
        \n dest_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
        \n dest_addr.<\/span>nl_pid =<\/span> 0<\/span>;<\/span> \/* \u6d88\u606f\u7684\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4 *\/<\/span>
        \n dest_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span> \/* \u672c\u793a\u4f8b\u4e2d\u65e0\u9700\u4f7f\u7528\u8be5\u5b57\u6bb5 *\/<\/span><\/p>\n

        \/\/ \u5c06\u5957\u63a5\u5b57\u548c Netlink \u5730\u5740\u7ed3\u6784\u4f53\u8fdb\u884c\u7ed1\u5b9a<\/span>
        \n if<\/span>(<\/span>–<\/span>1<\/span> ==<\/span> bind<\/span>(<\/span>sock_fd,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>dest_addr,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"can't bind sockfd with sockaddr_nl!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        if<\/span>(<\/span>NULL<\/span> ==<\/span> (<\/span>nlh=<\/span>(<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"alloc mem failed!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        memset<\/span>(<\/span>nlh,<\/span>0<\/span>,<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n \/* \u586b\u5145 Netlink \u6d88\u606f\u5934\u90e8 *\/<\/span>
        \n nlh-><\/span>nlmsg_len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n nlh-><\/span>nlmsg_pid =<\/span> 0<\/span>;<\/span>
        \n nlh-><\/span>nlmsg_type =<\/span> NLMSG_NOOP;<\/span> \/\/ \u6807\u8bc6\u8be5 Netlink \u6d88\u606f\u8d1f\u8f7d\u4e3a\u4e00\u6761\u7a7a\u6d88\u606f<\/span>
        \n nlh-><\/span>nlmsg_flags =<\/span> 0<\/span>;<\/span><\/p>\n

        \/* \u8bbe\u7f6e Netlink \u7684\u6d88\u606f\u5185\u5bb9，\u6570\u636e\u6765\u81ea\u547d\u4ee4\u884c\u8f93\u5165\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570 *\/<\/span>
        \n strcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span> argv[<\/span>1<\/span>]<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u6b64\u4e3a\u56fa\u5b9a\u4f7f\u7528\u6a21\u677f，\u5176\u8be6\u7ec6\u539f\u7406\u5c06\u5728\u540e\u7eed Socket \u6df1\u5165\u8bb2\u89e3\u4e2d\u9610\u8ff0 *\/<\/span>
        \n memset<\/span>(<\/span>&<\/span>iov,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>iov)<\/span>)<\/span>;<\/span>
        \n iov.<\/span>iov_base =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>nlh;<\/span>
        \n iov.<\/span>iov_len =<\/span> nlh-><\/span>nlmsg_len;<\/span>
        \n memset<\/span>(<\/span>&<\/span>msg,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>msg)<\/span>)<\/span>;<\/span>
        \n msg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
        \n msg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

        \/\/ \u901a\u8fc7 Netlink socket \u5411\u5185\u6838\u53d1\u9001\u6d88\u606f<\/span>
        \n sendmsg<\/span>(<\/span>sock_fd,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u5173\u95ed netlink \u5957\u63a5\u5b57 *\/<\/span>
        \n close<\/span>(<\/span>sock_fd)<\/span>;<\/span>
        \n free<\/span>(<\/span>nlh)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \u4e0a\u8ff0\u4ee3\u7801\u7684\u903b\u8f91\u57fa\u4e8e\u6807\u51c6 Socket \u7f16\u7a0b API \u5b9e\u73b0，\u552f\u4e00\u7684\u5dee\u5f02\u5728\u4e8e\u672c\u6b21\u7f16\u7a0b\u9488\u5bf9 Netlink \u534f\u8bae\u7c07\u8fdb\u884c\u3002\u6b64\u5904\u63d0\u524d\u5f15\u5165\u4e86 BSD \u5c42\u7684\u6d88\u606f\u7ed3\u6784\u4f53 struct msghdr{}（\u5b9a\u4e49\u5728\u5bf9\u5e94\u5934\u6587\u4ef6\u4e2d）\u4e0e\u6570\u636e\u5757\u7ed3\u6784\u4f53 struct iovec{}（\u5b9a\u4e49\u5728\u5bf9\u5e94\u5934\u6587\u4ef6\u4e2d），\u5176\u8be6\u7ec6\u539f\u7406\u5c06\u5728\u540e\u7eed Socket \u6df1\u5165\u8bb2\u89e3\u4e2d\u9610\u8ff0，\u5f53\u524d\u4ec5\u9700\u638c\u63e1\u5176\u56fa\u5b9a\u4f7f\u7528\u65b9\u5f0f\u3002<\/p>\n

        \u6b64\u5916，\u9700\u8981\u91cd\u70b9\u5173\u6ce8 Netlink \u5730\u5740\u7ed3\u6784\u4f53\u4e0e\u6d88\u606f\u5934\u7ed3\u6784\u4f53\u4e2d pid \u5b57\u6bb5\u503c\u4e3a <\/p>\n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span> \u7684\u573a\u666f，\u907f\u514d\u51fa\u73b0\u6982\u5ff5\u6df7\u6dc6，\u76f8\u5173\u603b\u7ed3\u5982\u4e0b\u8868\u6240\u793a：<\/p>\n\n\u5b57\u6bb5\u503c\u4e3a 0 \u7684\u9002\u7528\u573a\u666f<\/tr>\n\n\n\n
        netlink \u5730\u5740\u7ed3\u6784\u4f53.nl_pid<\/td>\n1\u3001\u5185\u6838\u53d1\u51fa\u7684\u591a\u64ad\u62a5\u6587；2\u3001\u6d88\u606f\u7684\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4（\u5373\u4ece\u7528\u6237\u7a7a\u95f4\u53d1\u5f80\u5185\u6838\u7a7a\u95f4\u7684\u6d88\u606f）<\/td>\n<\/tr>\n
        netlink \u6d88\u606f\u5934\u7ed3\u6784\u4f53.nlmsg_pid<\/td>\n\u5185\u6838\u4e3b\u52a8\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u7684\u6d88\u606f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        \u672c\u793a\u4f8b\u5b9e\u73b0\u7684\u662f\u4ece\u7528\u6237\u7a7a\u95f4\u5230\u5185\u6838\u7a7a\u95f4\u7684\u5355\u5411\u6570\u636e\u901a\u4fe1，\u56e0\u6b64\u5728 Netlink \u5730\u5740\u7ed3\u6784\u4f53\u4e2d\u8bbe\u7f6e dest_addr.nl_pid = 0（\u6807\u8bc6\u6d88\u606f\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4），\u5728\u586b\u5145 Netlink \u6d88\u606f\u5934\u90e8\u65f6\u8bbe\u7f6e nlh->nlmsg_pid = 0\u3002<\/p>\n

        \u540c\u65f6，\u9700\u8981\u638c\u63e1\u4ee5\u4e0b\u4e24\u4e2a\u5b8f\u7684\u4f7f\u7528\u65b9\u6cd5：<\/p>\n

      • NLMSG_SPACE(MAX_PAYLOAD)：\u8be5\u5b8f\u7528\u4e8e\u8fd4\u56de\u4e0d\u5c0f\u4e8e MAX_PAYLOAD \u4e14\u6ee1\u8db3 \n

        4 <\/p>\n

        4 <\/p>\n

        <\/span><\/span>4<\/span><\/span><\/span><\/span><\/span> \u5b57\u8282\u5bf9\u9f50\u7684\u6700\u5c0f\u957f\u5ea6\u503c，\u901a\u5e38\u7528\u4e8e\u5185\u5b58\u7533\u8bf7\u65f6\u6307\u5b9a\u6240\u9700\u7684\u5185\u5b58\u5b57\u8282\u6570\u3002\u4e0e NLMSG_LENGTH(len) \u7684\u5dee\u5f02\u5728\u4e8e：\u524d\u8005\u7533\u8bf7\u7684\u7a7a\u95f4\u4e0d\u5305\u542b Netlink \u6d88\u606f\u5934\u90e8\u6240\u5360\u5b57\u8282\u6570，\u540e\u8005\u4e3a\u6d88\u606f\u8d1f\u8f7d\u4e0e\u6d88\u606f\u5934\u7684\u603b\u957f\u5ea6\u3002<\/li>\n

      • NLMSG_DATA(nlh)：\u8be5\u5b8f\u7528\u4e8e\u8fd4\u56de Netlink \u6d88\u606f\u4e2d\u6570\u636e\u90e8\u5206\u7684\u9996\u5730\u5740，\u5728\u5199\u5165\u4e0e\u8bfb\u53d6\u6d88\u606f\u6570\u636e\u90e8\u5206\u65f6\u4f1a\u9891\u7e41\u4f7f\u7528\u3002<\/li>\n

        \u5185\u6838\u7a7a\u95f4\u793a\u4f8b\u4ee3\u7801\u3010mynlkern.c\u3011<\/h4>\n

        #<\/span>include<\/span> <linux\/kernel.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/module.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/skbuff.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/init.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/ip.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/sched.h><\/span><\/span>
        \n#<\/span>include<\/span> <net\/sock.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span><\/p>\n

        MODULE_LICENSE<\/span>(<\/span>"GPL"<\/span>)<\/span>;<\/span>
        \nMODULE_AUTHOR<\/span>(<\/span>"Koorey King"<\/span>)<\/span>;<\/span><\/p>\n

        struct<\/span> sock<\/span> *<\/span>nl_sk =<\/span> NULL<\/span>;<\/span>
        \nstatic<\/span> void<\/span> nl_data_ready<\/span> (<\/span>struct<\/span> sock<\/span> *<\/span>sk,<\/span> int<\/span> len)<\/span>
        \n{<\/span>
        \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span><\/p>\n

        while<\/span>(<\/span>(<\/span>skb =<\/span> skb_dequeue<\/span>(<\/span>&<\/span>sk-><\/span>sk_receive_queue)<\/span>)<\/span> !=<\/span> NULL<\/span>)<\/span>
        \n {<\/span>
        \n nlh =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>skb-><\/span>data;<\/span>
        \n printk<\/span>(<\/span>"%s: received netlink message payload: %s \\\\n"<\/span>,<\/span> __FUNCTION__,<\/span> (<\/span>char<\/span>*<\/span>)<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>)<\/span>;<\/span>
        \n kfree_skb<\/span>(<\/span>skb)<\/span>;<\/span>
        \n }<\/span>
        \n printk<\/span>(<\/span>"recvied finished!\\\\n"<\/span>)<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> int<\/span> __init myinit_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n printk<\/span>(<\/span>"my netlink in\\\\n"<\/span>)<\/span>;<\/span>
        \n nl_sk =<\/span> netlink_kernel_create<\/span>(<\/span>NETLINK_TEST,<\/span>0<\/span>,<\/span>nl_data_ready,<\/span>THIS_MODULE)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> void<\/span> __exit mycleanup_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n printk<\/span>(<\/span>"my netlink out!\\\\n"<\/span>)<\/span>;<\/span>
        \n sock_release<\/span>(<\/span>nl_sk-><\/span>sk_socket)<\/span>;<\/span>
        \n}<\/span><\/p>\n

        module_init<\/span>(<\/span>myinit_module)<\/span>;<\/span>
        \nmodule_exit<\/span>(<\/span>mycleanup_module)<\/span>;<\/span><\/p>\n

        \u5728\u5185\u6838\u6a21\u5757\u7684\u521d\u59cb\u5316\u51fd\u6570\u4e2d，\u901a\u8fc7 netlink_kernel_create(NETLINK_TEST,0,nl_data_ready,THIS_MODULE) \u51fd\u6570\u521b\u5efa\u4e86\u4e00\u4e2a\u5185\u6838\u6001 Socket，\u8be5\u51fd\u6570\u5404\u53c2\u6570\u7684\u542b\u4e49\u5982\u4e0b：<\/p>\n

      • \u7b2c\u4e00\u4e2a\u53c2\u6570：\u81ea\u5b9a\u4e49\u534f\u8bae\u7684\u534f\u8bae\u53f7（\u672c\u6b21\u5b9e\u9a8c\u4e3a NETLINK_TEST）；<\/li>\n
      • \u7b2c\u4e8c\u4e2a\u53c2\u6570：\u591a\u64ad\u7ec4\u53f7，\u672c\u9636\u6bb5\u5b9e\u9a8c\u65e0\u9700\u4f7f\u7528，\u7f6e\u4e3a \n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>；<\/li>\n

      • \u7b2c\u4e09\u4e2a\u53c2\u6570：\u56de\u8c03\u51fd\u6570，\u5f53\u5185\u6838\u7684 Netlink Socket \u63a5\u6536\u5230\u6570\u636e\u65f6，\u5c06\u89e6\u53d1\u8be5\u51fd\u6570\u8fdb\u884c\u6570\u636e\u5904\u7406；<\/li>\n
      • \u7b2c\u56db\u4e2a\u53c2\u6570：\u5185\u6838\u6a21\u5757\u6807\u8bc6，\u4f7f\u7528 THIS_MODULE \u5373\u53ef\u3002<\/li>\n

        \u5728\u56de\u8c03\u51fd\u6570 nl_data_ready() \u4e2d，\u901a\u8fc7\u5faa\u73af\u4ece Socket \u7684\u63a5\u6536\u961f\u5217\u4e2d\u83b7\u53d6\u6570\u636e，\u83b7\u53d6\u5230\u6570\u636e\u540e\u5c06\u5176\u6253\u5370\u8f93\u51fa，\u5e76\u91ca\u653e\u5bf9\u5e94\u7684\u7f13\u51b2\u533a\u8d44\u6e90\u3002\u5728\u534f\u8bae\u6808\u7684 INET \u5c42\u4e2d，\u6570\u636e\u7684\u5b58\u50a8\u4f9d\u8d56 sk_buff \u7ed3\u6784\u4f53\u5b9e\u73b0，\u56e0\u6b64\u53ef\u901a\u8fc7 nlh = (struct nlmsghdr *)skb->data \u83b7\u53d6 Netlink \u6d88\u606f\u4f53，\u518d\u901a\u8fc7 NLMSG_DATA(nlh) \u5b9a\u4f4d\u5230 Netlink \u6d88\u606f\u7684\u8d1f\u8f7d\u6570\u636e\u3002<\/p>\n

        \u5c06\u4e0a\u8ff0\u4ee3\u7801\u7f16\u8bd1\u540e，\u5373\u53ef\u8fdb\u884c\u6d4b\u8bd5\u9a8c\u8bc1，\u83b7\u53d6\u5bf9\u5e94\u7684\u8fd0\u884c\u7ed3\u679c\u3002<\/p>\n

        Stage 2：\u7528\u6237<->\u5185\u6838\u53cc\u5411\u6570\u636e\u901a\u4fe1<\/h3>\n

        \u5bf9 Stage 1 \u4e2d\u7684\u4ee3\u7801\u8fdb\u884c\u5c0f\u5e45\u4fee\u6539，\u5373\u53ef\u5b9e\u73b0\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u4e4b\u95f4\u7684\u53cc\u5411\u6570\u636e\u901a\u4fe1，\u5177\u4f53\u4fee\u6539\u5982\u4e0b\u3002<\/p>\n

        \u7528\u6237\u7a7a\u95f4\u4ee3\u7801\u4fee\u6539<\/h4>\n

        #<\/span>include<\/span> <sys\/stat.h><\/span><\/span>
        \n#<\/span>include<\/span> <unistd.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdio.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdlib.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/socket.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <string.h><\/span><\/span>
        \n#<\/span>include<\/span> <asm\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/socket.h><\/span><\/span><\/p>\n

        #<\/span>define<\/span> MAX_PAYLOAD<\/span> 1024<\/span> <\/span>\/* \u6d88\u606f\u6700\u5927\u8d1f\u8f7d\u4e3a 1024 \u5b57\u8282 *\/<\/span><\/span><\/p>\n

        int<\/span> main<\/span>(<\/span>int<\/span> argc,<\/span> char<\/span>*<\/span> argv[<\/span>]<\/span>)<\/span>
        \n{<\/span>
        \n struct<\/span> sockaddr_nl<\/span> dest_addr;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
        \n struct<\/span> iovec<\/span> iov;<\/span>
        \n int<\/span> sock_fd=<\/span>–<\/span>1<\/span>;<\/span>
        \n struct<\/span> msghdr<\/span> msg;<\/span><\/p>\n

        if<\/span>(<\/span>–<\/span>1<\/span> ==<\/span> (<\/span>sock_fd=<\/span>socket<\/span>(<\/span>PF_NETLINK,<\/span> SOCK_RAW,<\/span>NETLINK_TEST)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"can't create netlink socket!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span>
        \n memset<\/span>(<\/span>&<\/span>dest_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span>
        \n dest_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
        \n dest_addr.<\/span>nl_pid =<\/span> 0<\/span>;<\/span> \/* \u6d88\u606f\u7684\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4 *\/<\/span>
        \n dest_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span> \/* \u672c\u793a\u4f8b\u4e2d\u65e0\u9700\u4f7f\u7528\u8be5\u5b57\u6bb5 *\/<\/span><\/p>\n

        if<\/span>(<\/span>–<\/span>1<\/span> ==<\/span> bind<\/span>(<\/span>sock_fd,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>dest_addr,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"can't bind sockfd with sockaddr_nl!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span>
        \n if<\/span>(<\/span>NULL<\/span> ==<\/span> (<\/span>nlh=<\/span>(<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"alloc mem failed!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        memset<\/span>(<\/span>nlh,<\/span>0<\/span>,<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n \/* \u586b\u5145 Netlink \u6d88\u606f\u5934\u90e8 *\/<\/span>
        \n nlh-><\/span>nlmsg_len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n nlh-><\/span>nlmsg_pid =<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u5e0c\u671b\u83b7\u53d6\u5185\u6838\u54cd\u5e94，\u56e0\u6b64\u8bbe\u7f6e\u5f53\u524d\u8fdb\u7a0b ID \u4f9b\u5185\u6838\u8bc6\u522b<\/span>
        \n nlh-><\/span>nlmsg_type =<\/span> NLMSG_NOOP;<\/span> \/\/ \u6807\u8bc6\u8be5 Netlink \u6d88\u606f\u8d1f\u8f7d\u4e3a\u4e00\u6761\u7a7a\u6d88\u606f<\/span>
        \n nlh-><\/span>nlmsg_flags =<\/span> 0<\/span>;<\/span><\/p>\n

        \/* \u8bbe\u7f6e Netlink \u7684\u6d88\u606f\u5185\u5bb9，\u6570\u636e\u6765\u81ea\u547d\u4ee4\u884c\u8f93\u5165\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570 *\/<\/span>
        \n strcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span> argv[<\/span>1<\/span>]<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u6b64\u4e3a\u56fa\u5b9a\u4f7f\u7528\u6a21\u677f，\u5176\u8be6\u7ec6\u539f\u7406\u5c06\u5728\u540e\u7eed Socket \u6df1\u5165\u8bb2\u89e3\u4e2d\u9610\u8ff0 *\/<\/span>
        \n memset<\/span>(<\/span>&<\/span>iov,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>iov)<\/span>)<\/span>;<\/span>
        \n iov.<\/span>iov_base =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>nlh;<\/span>
        \n iov.<\/span>iov_len =<\/span> nlh-><\/span>nlmsg_len;<\/span>
        \n memset<\/span>(<\/span>&<\/span>msg,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>msg)<\/span>)<\/span>;<\/span>
        \n msg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
        \n msg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

        \/\/ \u901a\u8fc7 Netlink socket \u5411\u5185\u6838\u53d1\u9001\u6d88\u606f<\/span>
        \n sendmsg<\/span>(<\/span>sock_fd,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u63a5\u6536\u5185\u6838\u8fd4\u56de\u7684\u54cd\u5e94\u6d88\u606f<\/span>
        \n printf<\/span>(<\/span>"waiting message from kernel!\\\\n"<\/span>)<\/span>;<\/span>
        \n memset<\/span>(<\/span>(<\/span>char<\/span>*<\/span>)<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span>0<\/span>,<\/span>1024<\/span>)<\/span>;<\/span>
        \n recvmsg<\/span>(<\/span>sock_fd,<\/span>&<\/span>msg,<\/span>0<\/span>)<\/span>;<\/span>
        \n printf<\/span>(<\/span>"Got response: %s\\\\n"<\/span>,<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u5173\u95ed netlink \u5957\u63a5\u5b57 *\/<\/span>
        \n close<\/span>(<\/span>sock_fd)<\/span>;<\/span>
        \n free<\/span>(<\/span>nlh)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \u5185\u6838\u7a7a\u95f4\u4ee3\u7801\u4fee\u6539<\/h4>\n

        #<\/span>include<\/span> <linux\/kernel.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/module.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/skbuff.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/init.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/ip.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/sched.h><\/span><\/span>
        \n#<\/span>include<\/span> <net\/sock.h><\/span><\/span>
        \n#<\/span>include<\/span> <net\/netlink.h><\/span> \/* \u8be5\u5934\u6587\u4ef6\u5305\u542b\u4e86 linux\/netlink.h，\u540c\u65f6\u63d0\u4f9b nlmsg_put() \u7b49 API \u51fd\u6570 *\/<\/span><\/span><\/p>\n

        MODULE_LICENSE<\/span>(<\/span>"GPL"<\/span>)<\/span>;<\/span>
        \nMODULE_AUTHOR<\/span>(<\/span>"Koorey King"<\/span>)<\/span>;<\/span><\/p>\n

        #<\/span>define<\/span> MAX_MSGSIZE<\/span> 1024<\/span> <\/span>\/* \u6d88\u606f\u6700\u5927\u957f\u5ea6\u4e3a 1024 \u5b57\u8282 *\/<\/span><\/span><\/p>\n

        struct<\/span> sock<\/span> *<\/span>nl_sk =<\/span> NULL<\/span>;<\/span><\/p>\n

        \/\/ \u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6d88\u606f\u7684\u63a5\u53e3\u51fd\u6570<\/span>
        \nvoid<\/span> sendnlmsg<\/span>(<\/span>char<\/span> *<\/span>message,<\/span>int<\/span> dstPID)<\/span>
        \n{<\/span>
        \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh;<\/span>
        \n int<\/span> len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_MSGSIZE)<\/span>;<\/span>
        \n int<\/span> slen =<\/span> 0<\/span>;<\/span><\/p>\n

        if<\/span>(<\/span>!<\/span>message ||<\/span> !<\/span>nl_sk)<\/span>{<\/span>
        \n return<\/span>;<\/span>
        \n }<\/span><\/p>\n

        \/\/ \u4e3a\u65b0\u7684 sk_buffer \u7533\u8bf7\u7a7a\u95f4<\/span>
        \n skb =<\/span> alloc_skb<\/span>(<\/span>len,<\/span> GFP_KERNEL)<\/span>;<\/span>
        \n if<\/span>(<\/span>!<\/span>skb)<\/span>{<\/span>
        \n printk<\/span>(<\/span>KERN_ERR "my_net_link: alloc_skb Error.\/n"<\/span>)<\/span>;<\/span>
        \n return<\/span>;<\/span>
        \n }<\/span><\/p>\n

        slen =<\/span> strlen<\/span>(<\/span>message)<\/span>+<\/span>1<\/span>;<\/span><\/p>\n

        \/\/ \u7528 nlmsg_put() \u6765\u8bbe\u7f6e netlink \u6d88\u606f\u5934\u90e8<\/span>
        \n nlh =<\/span> nlmsg_put<\/span>(<\/span>skb,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> MAX_MSGSIZE,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u8bbe\u7f6e Netlink \u7684\u63a7\u5236\u5757<\/span>
        \n NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>pid =<\/span> 0<\/span>;<\/span> \/\/ \u6d88\u606f\u53d1\u9001\u8005\u4e3a\u5185\u6838\u7a7a\u95f4，\u7f6e\u4e3a 0<\/span>
        \n NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>dst_group =<\/span> 0<\/span>;<\/span> \/\/ \u76ee\u7684\u4e3a\u5355\u4e2a\u8fdb\u7a0b，\u8be5\u5b57\u6bb5\u7f6e\u4e3a 0<\/span><\/p>\n

        message[<\/span>slen]<\/span> =<\/span> '\\\\0'<\/span>;<\/span>
        \n memcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span> message,<\/span> slen+<\/span>1<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u901a\u8fc7 netlink_unicast() \u5c06\u6d88\u606f\u53d1\u9001\u81f3\u7528\u6237\u7a7a\u95f4\u6307\u5b9a PID \u7684\u8fdb\u7a0b<\/span>
        \n netlink_unicast<\/span>(<\/span>nl_sk,<\/span>skb,<\/span>dstPID,<\/span>0<\/span>)<\/span>;<\/span>
        \n printk<\/span>(<\/span>"send OK!\\\\n"<\/span>)<\/span>;<\/span>
        \n return<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> void<\/span> nl_data_ready<\/span> (<\/span>struct<\/span> sock<\/span> *<\/span>sk,<\/span> int<\/span> len)<\/span>
        \n{<\/span>
        \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span><\/p>\n

        while<\/span>(<\/span>(<\/span>skb =<\/span> skb_dequeue<\/span>(<\/span>&<\/span>sk-><\/span>sk_receive_queue)<\/span>)<\/span> !=<\/span> NULL<\/span>)<\/span>
        \n {<\/span>
        \n nlh =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>skb-><\/span>data;<\/span>
        \n printk<\/span>(<\/span>"%s: received netlink message payload: %s \\\\n"<\/span>,<\/span> __FUNCTION__,<\/span> (<\/span>char<\/span>*<\/span>)<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>)<\/span>;<\/span>
        \n kfree_skb<\/span>(<\/span>skb)<\/span>;<\/span>
        \n \/\/ \u63d0\u53d6\u7528\u6237\u8fdb\u7a0b PID，\u5411\u5176\u53d1\u9001\u54cd\u5e94\u6d88\u606f<\/span>
        \n sendnlmsg<\/span>(<\/span>"I see you"<\/span>,<\/span>nlh-><\/span>nlmsg_pid)<\/span>;<\/span>
        \n }<\/span>
        \n printk<\/span>(<\/span>"recvied finished!\\\\n"<\/span>)<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> int<\/span> __init myinit_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n printk<\/span>(<\/span>"my netlink in\\\\n"<\/span>)<\/span>;<\/span>
        \n nl_sk =<\/span> netlink_kernel_create<\/span>(<\/span>NETLINK_TEST,<\/span>0<\/span>,<\/span>nl_data_ready,<\/span>THIS_MODULE)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> void<\/span> __exit mycleanup_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n printk<\/span>(<\/span>"my netlink out!\\\\n"<\/span>)<\/span>;<\/span>
        \n sock_release<\/span>(<\/span>nl_sk-><\/span>sk_socket)<\/span>;<\/span>
        \n}<\/span><\/p>\n

        module_init<\/span>(<\/span>myinit_module)<\/span>;<\/span>
        \nmodule_exit<\/span>(<\/span>mycleanup_module)<\/span>;<\/span><\/p>\n

        \u5c06\u4fee\u6539\u540e\u7684\u4ee3\u7801\u91cd\u65b0\u7f16\u8bd1\u540e，\u5373\u53ef\u8fdb\u884c\u6d4b\u8bd5\u9a8c\u8bc1，\u83b7\u53d6\u5bf9\u5e94\u7684\u53cc\u5411\u901a\u4fe1\u8fd0\u884c\u7ed3\u679c\u3002<\/p>\n

        Stage 3：\u65e0 bind() \u8c03\u7528\u7684\u53cc\u5411\u6570\u636e\u901a\u4fe1<\/h3>\n

        \u524d\u6587\u63d0\u53ca，\u7528\u6237\u8fdb\u7a0b\u4ec5\u5728\u9700\u8981\u52a0\u5165\u591a\u64ad\u7ec4\u65f6\u624d\u9700\u8981\u8c03\u7528 bind() \u51fd\u6570\u3002Stage 2 \u4e2d\u65e0\u591a\u64ad\u7ec4\u76f8\u5173\u9700\u6c42，\u5374\u8c03\u7528\u4e86 bind() \u51fd\u6570，\u672c\u6b21\u5c06\u5bf9\u4ee3\u7801\u8fdb\u884c\u4fee\u6539，\u79fb\u9664 bind() \u8c03\u7528，\u6539\u7528 sendto() \u4e0e recvfrom() \u51fd\u6570\u5b9e\u73b0\u6570\u636e\u7684\u6536\u53d1\u3002<\/p>\n

        \u7528\u6237\u7a7a\u95f4\u4ee3\u7801\u4fee\u6539<\/h4>\n

        #<\/span>include<\/span> <sys\/stat.h><\/span><\/span>
        \n#<\/span>include<\/span> <unistd.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdio.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdlib.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/socket.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <string.h><\/span><\/span>
        \n#<\/span>include<\/span> <asm\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/socket.h><\/span><\/span><\/p>\n

        #<\/span>define<\/span> MAX_PAYLOAD<\/span> 1024<\/span> <\/span>\/* \u6d88\u606f\u6700\u5927\u8d1f\u8f7d\u4e3a 1024 \u5b57\u8282 *\/<\/span><\/span><\/p>\n

        int<\/span> main<\/span>(<\/span>int<\/span> argc,<\/span> char<\/span>*<\/span> argv[<\/span>]<\/span>)<\/span>
        \n{<\/span>
        \n struct<\/span> sockaddr_nl<\/span> dest_addr;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
        \n \/\/ struct iovec iov; \/\/ \u65e0\u9700\u4f7f\u7528\u8be5\u7ed3\u6784\u4f53<\/span>
        \n int<\/span> sock_fd=<\/span>–<\/span>1<\/span>;<\/span>
        \n \/\/ struct msghdr msg; \/\/ \u65e0\u9700\u4f7f\u7528\u8be5\u7ed3\u6784\u4f53<\/span><\/p>\n

        if<\/span>(<\/span>–<\/span>1<\/span> ==<\/span> (<\/span>sock_fd=<\/span>socket<\/span>(<\/span>PF_NETLINK,<\/span> SOCK_RAW,<\/span>NETLINK_TEST)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"can't create netlink socket!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span>
        \n memset<\/span>(<\/span>&<\/span>dest_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span>
        \n dest_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
        \n dest_addr.<\/span>nl_pid =<\/span> 0<\/span>;<\/span> \/* \u6d88\u606f\u7684\u63a5\u6536\u65b9\u4e3a\u5185\u6838\u7a7a\u95f4 *\/<\/span>
        \n dest_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span> \/* \u672c\u793a\u4f8b\u4e2d\u65e0\u9700\u4f7f\u7528\u8be5\u5b57\u6bb5 *\/<\/span><\/p>\n

        \/* \u79fb\u9664 bind() \u51fd\u6570\u8c03\u7528 *\/<\/span>
        \n \/*
        \n if(-1 == bind(sock_fd, (struct sockaddr*)&dest_addr, sizeof(dest_addr))){
        \n perror("can't bind sockfd with sockaddr_nl!");
        \n return 1;
        \n }
        \n *\/<\/span><\/p>\n

        if<\/span>(<\/span>NULL<\/span> ==<\/span> (<\/span>nlh=<\/span>(<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>)<\/span>)<\/span>)<\/span>{<\/span>
        \n perror<\/span>(<\/span>"alloc mem failed!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span>
        \n memset<\/span>(<\/span>nlh,<\/span>0<\/span>,<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n \/* \u586b\u5145 Netlink \u6d88\u606f\u5934\u90e8 *\/<\/span>
        \n nlh-><\/span>nlmsg_len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>;<\/span>
        \n nlh-><\/span>nlmsg_pid =<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span>\/\/ \u5e0c\u671b\u83b7\u53d6\u5185\u6838\u54cd\u5e94，\u56e0\u6b64\u8bbe\u7f6e\u5f53\u524d\u8fdb\u7a0b ID \u4f9b\u5185\u6838\u8bc6\u522b<\/span>
        \n nlh-><\/span>nlmsg_type =<\/span> NLMSG_NOOP;<\/span> \/\/ \u6807\u8bc6\u8be5 Netlink \u6d88\u606f\u8d1f\u8f7d\u4e3a\u4e00\u6761\u7a7a\u6d88\u606f<\/span>
        \n nlh-><\/span>nlmsg_flags =<\/span> 0<\/span>;<\/span><\/p>\n

        \/* \u8bbe\u7f6e Netlink \u7684\u6d88\u606f\u5185\u5bb9，\u6570\u636e\u6765\u81ea\u547d\u4ee4\u884c\u8f93\u5165\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570 *\/<\/span>
        \n strcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span> argv[<\/span>1<\/span>]<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u8be5\u6a21\u677f\u65e0\u9700\u4f7f\u7528 *\/<\/span>
        \n \/*
        \n memset(&iov, 0, sizeof(iov));
        \n iov.iov_base = (void *)nlh;
        \n iov.iov_len = nlh->nlmsg_len;
        \n memset(&msg, 0, sizeof(msg));
        \n msg.msg_iov = &iov;
        \n msg.msg_iovlen = 1;
        \n *\/<\/span><\/p>\n

        \/\/ \u6539\u7528 sendto() \u51fd\u6570\u5411\u5185\u6838\u53d1\u9001\u6d88\u606f<\/span>
        \n \/\/ sendmsg(sock_fd, &msg, 0);<\/span>
        \n sendto<\/span>(<\/span>sock_fd,<\/span>nlh,<\/span>NLMSG_LENGTH<\/span>(<\/span>MAX_PAYLOAD)<\/span>,<\/span>0<\/span>,<\/span>(<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>(<\/span>&<\/span>dest_addr)<\/span>,<\/span>sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u63a5\u6536\u5185\u6838\u8fd4\u56de\u7684\u54cd\u5e94\u6d88\u606f，\u6539\u7528 recvfrom() \u51fd\u6570<\/span>
        \n printf<\/span>(<\/span>"waiting message from kernel!\\\\n"<\/span>)<\/span>;<\/span>
        \n memset<\/span>(<\/span>nlh,<\/span>0<\/span>,<\/span>MAX_PAYLOAD)<\/span>;<\/span> \/\/ \u6e05\u7a7a\u6574\u4e2a Netlink \u6d88\u606f（\u5305\u542b\u6d88\u606f\u5934\u4e0e\u8d1f\u8f7d）<\/span>
        \n \/\/ recvmsg(sock_fd,&msg,0);<\/span>
        \n recvfrom<\/span>(<\/span>sock_fd,<\/span>nlh,<\/span>NLMSG_LENGTH<\/span>(<\/span>MAX_PAYLOAD)<\/span>,<\/span>0<\/span>,<\/span>(<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>(<\/span>&<\/span>dest_addr)<\/span>,<\/span>NULL<\/span>)<\/span>;<\/span>
        \n printf<\/span>(<\/span>"Got response: %s\\\\n"<\/span>,<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>)<\/span>;<\/span><\/p>\n

        \/* \u5173\u95ed netlink \u5957\u63a5\u5b57 *\/<\/span>
        \n close<\/span>(<\/span>sock_fd)<\/span>;<\/span>
        \n free<\/span>(<\/span>nlh)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \u8bf4\u660e<\/h4>\n

        \u5185\u6838\u7a7a\u95f4\u7684\u4ee3\u7801\u65e0\u9700\u8fdb\u884c\u4efb\u4f55\u4fee\u6539，\u4ecd\u901a\u8fc7 netlink_unicast() \u51fd\u6570\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u54cd\u5e94\u6d88\u606f\u3002\u5c06\u4fee\u6539\u540e\u7684\u4ee3\u7801\u91cd\u65b0\u7f16\u8bd1\u540e，\u5176\u8fd0\u884c\u6548\u679c\u4e0e Stage 2 \u5b8c\u5168\u4e00\u81f4\u3002<\/p>\n

        \u7531\u6b64\u53ef\u5f97\u7ed3\u8bba：\u5728 Netlink \u7a0b\u5e8f\u5f00\u53d1\u8fc7\u7a0b\u4e2d，\u82e5\u4e0d\u6d89\u53ca\u591a\u64ad\u673a\u5236，\u7528\u6237\u7a7a\u95f4\u7684 Socket \u4ee3\u7801\u65e0\u9700\u6267\u884c bind() \u7cfb\u7edf\u8c03\u7528，\u6b64\u65f6\u9700\u4f7f\u7528 sendto() \u4e0e recvfrom() \u51fd\u6570\u5b8c\u6210\u6570\u636e\u7684\u6536\u53d1；\u82e5\u6267\u884c\u4e86 bind() \u7cfb\u7edf\u8c03\u7528，\u540c\u6837\u53ef\u4ee5\u4f7f\u7528 sendto() \u4e0e recvfrom() \u51fd\u6570，\u4f46\u9700\u8c03\u6574\u5bf9\u5e94\u7684\u53c2\u6570\u4f20\u9012，\u6b64\u65f6\u66f4\u63a8\u8350\u4f7f\u7528 sendmsg() \u4e0e recvmsg() \u51fd\u6570\u5b8c\u6210\u6570\u636e\u6536\u53d1\u3002\u5f00\u53d1\u4eba\u5458\u53ef\u6839\u636e\u5b9e\u9645\u5e94\u7528\u573a\u666f\u7075\u6d3b\u9009\u62e9\u5bf9\u5e94\u7684\u5b9e\u73b0\u65b9\u5f0f\u3002<\/p>\n

        \n

        \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u901a\u4fe1\u2014\u2014Netlink（\u4e0b）<\/h2>\n

        wjlkoorey258 2012-11-15 19:50:53<\/p>\n

        Netlink \u591a\u64ad\u673a\u5236\u7684\u7528\u6cd5<\/h3>\n

        \u5728\u4e0a\u4e00\u8282\u7684\u5185\u5bb9\u4e2d，\u6240\u6709\u5b9e\u9a8c\u573a\u666f\u5747\u4ee5\u7528\u6237\u7a7a\u95f4\u4f5c\u4e3a\u6d88\u606f\u53d1\u8d77\u65b9，\u800c Netlink \u673a\u5236\u540c\u6837\u652f\u6301\u5185\u6838\u7a7a\u95f4\u4f5c\u4e3a\u4e3b\u52a8\u6d88\u606f\u53d1\u9001\u65b9，\u8be5\u573a\u666f\u901a\u5e38\u7528\u4e8e\u5185\u6838\u5411\u7528\u6237\u7a7a\u95f4\u4e3b\u52a8\u62a5\u544a\u81ea\u8eab\u72b6\u6001\u53d8\u5316，\u4f8b\u5982\u7528\u6237\u7a7a\u95f4\u611f\u77e5\u5230\u7684 USB \u70ed\u63d2\u62d4\u4e8b\u4ef6\u901a\u544a，\u4fbf\u662f\u57fa\u4e8e\u8be5\u673a\u5236\u5b9e\u73b0\u7684\u3002<\/p>\n

        \u672c\u6b21\u5b9e\u9a8c\u7684\u76ee\u6807\u4e3a：\u5b9e\u73b0\u4e00\u4e2a\u5185\u6838\u7ebf\u7a0b，\u8be5\u7ebf\u7a0b\u6bcf\u9694 <\/p>\n

        1 <\/p>\n

        1 <\/p>\n

        <\/span><\/span>1<\/span><\/span><\/span><\/span><\/span> \u79d2\u5411\u4e00\u4e2a\u6307\u5b9a\u591a\u64ad\u7ec4\u53d1\u9001\u4e00\u6761\u6d88\u606f，\u6240\u6709\u52a0\u5165\u8be5\u591a\u64ad\u7ec4\u7684\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5747\u53ef\u63a5\u6536\u5e76\u6253\u5370\u8be5\u6d88\u606f\u5185\u5bb9\u3002<\/p>\n

        Netlink \u5730\u5740\u7ed3\u6784\u4f53\u4e2d\u7684 nl_groups \u5b57\u6bb5\u4e3a <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u4f4d，\u8fd9\u610f\u5473\u7740\u6bcf\u79cd Netlink \u534f\u8bae\u6700\u591a\u652f\u6301 <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u4e2a\u591a\u64ad\u7ec4\u3002\u6b64\u5904\u7684\u201c\u6bcf\u79cd Netlink \u534f\u8bae\u201d\u6307\u7684\u662f Netlink \u534f\u8bae\u7c07\u4e2d\u7684\u5404\u7c7b\u9884\u5b9a\u4e49\u534f\u8bae（\u5982\u4e0b\u6240\u793a），\u4ee5\u53ca\u672c\u6b21\u5b9e\u9a8c\u4e2d\u81ea\u5b9a\u4e49\u7684 NETLINK_TEST \u534f\u8bae\u3002<\/p>\n

        #<\/span>define<\/span> NETLINK_ROUTE<\/span> 0<\/span> <\/span>\/* Routing\/device hook *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_UNUSED<\/span> 1<\/span> <\/span>\/* Unused number *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_USERSOCK<\/span> 2<\/span> <\/span>\/* Reserved for user mode socket protocols *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIREWALL<\/span> 3<\/span> <\/span>\/* Firewalling hook *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_INET_DIAG<\/span> 4<\/span> <\/span>\/* INET socket monitoring *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NFLOG<\/span> 5<\/span> <\/span>\/* netfilter\/iptables ULOG *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_XFRM<\/span> 6<\/span> <\/span>\/* ipsec *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_SELINUX<\/span> 7<\/span> <\/span>\/* SELinux event notifications *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_ISCSI<\/span> 8<\/span> <\/span>\/* Open-iSCSI *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_AUDIT<\/span> 9<\/span> <\/span>\/* auditing *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIB_LOOKUP<\/span> 10<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_CONNECTOR<\/span> 11<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NETFILTER<\/span> 12<\/span> <\/span>\/* netfilter subsystem *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_IP6_FW<\/span> 13<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_DNRTMSG<\/span> 14<\/span> <\/span>\/* DECnet routing messages *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_KOBJECT_UEVENT<\/span> 15<\/span> <\/span>\/* Kernel messages to userspace *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_GENERIC<\/span> 16<\/span><\/span><\/span>
        \n\/* leave room for NETLINK_DM (DM Events) *\/<\/span>
        \n#<\/span>define<\/span> NETLINK_SCSITRANSPORT<\/span> 18<\/span> <\/span>\/* SCSI Transports *\/<\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_ECRYPTFS<\/span> 19<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_TEST<\/span> 20<\/span> <\/span>\/* \u7528\u6237\u6dfb\u52a0\u7684\u81ea\u5b9a\u4e49\u534f\u8bae *\/<\/span><\/span><\/p>\n

        \u5728\u81ea\u5b9a\u4e49\u7684 NETLINK_TEST \u534f\u8bae\u4e2d，\u6700\u591a\u5141\u8bb8\u8bbe\u7f6e <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u4e2a\u591a\u64ad\u7ec4，\u6bcf\u4e2a\u591a\u64ad\u7ec4\u7531\u4e00\u4e2a\u72ec\u7acb\u7684\u6bd4\u7279\u4f4d\u8868\u793a，\u4e0d\u5b58\u5728\u591a\u64ad\u7ec4\u91cd\u590d\u7684\u60c5\u51b5\u3002\u5f00\u53d1\u4eba\u5458\u53ef\u6839\u636e\u5b9e\u9645\u9700\u6c42\u4e3a\u6bcf\u4e2a\u591a\u64ad\u7ec4\u5206\u914d\u5bf9\u5e94\u7684\u529f\u80fd，\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u82e5\u5bf9\u67d0\u4e2a\u591a\u64ad\u7ec4\u7684\u6d88\u606f\u611f\u5174\u8da3，\u53ef\u901a\u8fc7\u52a0\u5165\u8be5\u591a\u64ad\u7ec4\u7684\u65b9\u5f0f，\u63a5\u6536\u5185\u6838\u7a7a\u95f4\u5411\u8be5\u7ec4\u53d1\u9001\u7684\u591a\u64ad\u6d88\u606f\u3002<\/p>\n

        \u56de\u5230 Netlink \u5730\u5740\u7ed3\u6784\u4f53\u7684 nl_groups \u5b57\u6bb5，\u8be5\u5b57\u6bb5\u5b58\u50a8\u7684\u662f\u591a\u64ad\u7ec4\u7684\u5730\u5740\u63a9\u7801（\u5e76\u975e\u591a\u64ad\u7ec4\u53f7）\u3002\u5728 af_netlink.c \u6587\u4ef6\u4e2d，\u63d0\u4f9b\u4e86\u4ece\u591a\u64ad\u7ec4\u53f7\u8f6c\u6362\u4e3a\u591a\u64ad\u7ec4\u63a9\u7801\u7684\u51fd\u6570，\u5177\u4f53\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

        static<\/span> u32 netlink_group_mask<\/span>(<\/span>u32 group)<\/span>
        \n{<\/span>
        \n return<\/span> group ?<\/span> 1<\/span> <<<\/span> (<\/span>group –<\/span> 1<\/span>)<\/span> :<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \u7531\u6b64\u53ef\u77e5，\u5728\u7528\u6237\u7a7a\u95f4\u4ee3\u7801\u4e2d，\u82e5\u9700\u52a0\u5165\u591a\u64ad\u7ec4 <\/p>\n

        1 <\/p>\n

        1 <\/p>\n

        <\/span><\/span>1<\/span><\/span><\/span><\/span><\/span>，\u9700\u5c06 nl_groups \u5b57\u6bb5\u8bbe\u7f6e\u4e3a <\/p>\n

        1 <\/p>\n

        1 <\/p>\n

        <\/span><\/span>1<\/span><\/span><\/span><\/span><\/span>；\u591a\u64ad\u7ec4 <\/p>\n

        2 <\/p>\n

        2 <\/p>\n

        <\/span><\/span>2<\/span><\/span><\/span><\/span><\/span> \u5bf9\u5e94\u7684\u63a9\u7801\u4e3a <\/p>\n

        2 <\/p>\n

        2 <\/p>\n

        <\/span><\/span>2<\/span><\/span><\/span><\/span><\/span>；\u591a\u64ad\u7ec4 <\/p>\n

        3 <\/p>\n

        3 <\/p>\n

        <\/span><\/span>3<\/span><\/span><\/span><\/span><\/span> \u5bf9\u5e94\u7684\u63a9\u7801\u4e3a <\/p>\n

        4 <\/p>\n

        4 <\/p>\n

        <\/span><\/span>4<\/span><\/span><\/span><\/span><\/span>，\u4ee5\u6b64\u7c7b\u63a8\u3002\u82e5\u8be5\u5b57\u6bb5\u503c\u4e3a <\/p>\n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>，\u8868\u660e\u4e0d\u52a0\u5165\u4efb\u4f55\u591a\u64ad\u7ec4\u3002\u638c\u63e1\u8be5\u8f6c\u6362\u5173\u7cfb\u5177\u6709\u91cd\u8981\u610f\u4e49，\u56e0\u6b64\u53ef\u5728\u7528\u6237\u7a7a\u95f4\u4ee3\u7801\u4e2d\u5b9e\u73b0\u4e00\u4e2a\u529f\u80fd\u7c7b\u4f3c netlink_group_mask() \u7684\u51fd\u6570，\u5b8c\u6210\u591a\u64ad\u7ec4\u53f7\u5230\u591a\u64ad\u7ec4\u63a9\u7801\u7684\u8f6c\u6362\u3002<\/p>\n

        \u5b9e\u73b0\u4ee3\u7801<\/h3>\n

        \u7528\u6237\u7a7a\u95f4\u4ee3\u7801<\/h4>\n

        #<\/span>include<\/span> <sys\/stat.h><\/span><\/span>
        \n#<\/span>include<\/span> <unistd.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdio.h><\/span><\/span>
        \n#<\/span>include<\/span> <stdlib.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/socket.h><\/span><\/span>
        \n#<\/span>include<\/span> <sys\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <string.h><\/span><\/span>
        \n#<\/span>include<\/span> <asm\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/socket.h><\/span><\/span>
        \n#<\/span>include<\/span> <errno.h><\/span><\/span><\/p>\n

        #<\/span>define<\/span> MAX_PAYLOAD<\/span> 1024<\/span> <\/span>\/\/ Netlink \u6d88\u606f\u7684\u6700\u5927\u8f7d\u8377\u7684\u957f\u5ea6<\/span><\/span><\/p>\n

        \/\/ \u591a\u64ad\u7ec4\u53f7\u8f6c\u591a\u64ad\u7ec4\u63a9\u7801\u51fd\u6570<\/span>
        \nunsigned<\/span> int<\/span> netlink_group_mask<\/span>(<\/span>unsigned<\/span> int<\/span> group)<\/span>
        \n{<\/span>
        \n return<\/span> group ?<\/span> 1<\/span> <<<\/span> (<\/span>group –<\/span> 1<\/span>)<\/span> :<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        int<\/span> main<\/span>(<\/span>int<\/span> argc,<\/span> char<\/span>*<\/span> argv[<\/span>]<\/span>)<\/span>
        \n{<\/span>
        \n struct<\/span> sockaddr_nl<\/span> src_addr;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
        \n struct<\/span> iovec<\/span> iov;<\/span>
        \n struct<\/span> msghdr<\/span> msg;<\/span>
        \n int<\/span> sock_fd,<\/span> retval;<\/span><\/p>\n

        \/\/ \u521b\u5efa Socket<\/span>
        \n sock_fd =<\/span> socket<\/span>(<\/span>PF_NETLINK,<\/span> SOCK_RAW,<\/span> NETLINK_TEST)<\/span>;<\/span>
        \n if<\/span>(<\/span>sock_fd ==<\/span> –<\/span>1<\/span>)<\/span>{<\/span>
        \n printf<\/span>(<\/span>"error getting socket: %s"<\/span>,<\/span> strerror<\/span>(<\/span>errno)<\/span>)<\/span>;<\/span>
        \n return<\/span> –<\/span>1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        memset<\/span>(<\/span>&<\/span>src_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>src_addr)<\/span>)<\/span>;<\/span>
        \n src_addr.<\/span>nl_family =<\/span> PF_NETLINK;<\/span>
        \n src_addr.<\/span>nl_pid =<\/span> 0<\/span>;<\/span> \/\/ \u6807\u8bc6\u4ece\u5185\u6838\u63a5\u6536\u591a\u64ad\u6d88\u606f（\u53e6\u4e00\u4e2a\u542b\u4e49\u4e3a\u6d88\u606f\u53d1\u9001\u65b9\u4e3a\u5185\u6838）<\/span>
        \n src_addr.<\/span>nl_groups =<\/span> netlink_group_mask<\/span>(<\/span>atoi<\/span>(<\/span>argv[<\/span>1<\/span>]<\/span>)<\/span>)<\/span>;<\/span> \/\/ \u591a\u64ad\u7ec4\u63a9\u7801，\u7ec4\u53f7\u6765\u81ea\u547d\u4ee4\u884c\u8f93\u5165\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570<\/span><\/p>\n

        \/\/ \u52a0\u5165\u591a\u64ad\u7ec4\u5fc5\u987b\u8c03\u7528 bind() \u51fd\u6570<\/span>
        \n retval =<\/span> bind<\/span>(<\/span>sock_fd,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>src_addr,<\/span> sizeof<\/span>(<\/span>src_addr)<\/span>)<\/span>;<\/span>
        \n if<\/span>(<\/span>retval <<\/span> 0<\/span>)<\/span>{<\/span>
        \n printf<\/span>(<\/span>"bind failed: %s"<\/span>,<\/span> strerror<\/span>(<\/span>errno)<\/span>)<\/span>;<\/span>
        \n close<\/span>(<\/span>sock_fd)<\/span>;<\/span>
        \n return<\/span> –<\/span>1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        \/\/ \u4e3a\u63a5\u6536 Netlink \u6d88\u606f\u7533\u8bf7\u5b58\u50a8\u7a7a\u95f4<\/span>
        \n nlh =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>)<\/span>;<\/span>
        \n if<\/span>(<\/span>!<\/span>nlh)<\/span>{<\/span>
        \n printf<\/span>(<\/span>"malloc nlmsghdr error!\\\\n"<\/span>)<\/span>;<\/span>
        \n close<\/span>(<\/span>sock_fd)<\/span>;<\/span>
        \n return<\/span> –<\/span>1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        memset<\/span>(<\/span>nlh,<\/span> 0<\/span>,<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>)<\/span>;<\/span>
        \n iov.<\/span>iov_base =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>nlh;<\/span>
        \n iov.<\/span>iov_len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_PAYLOAD)<\/span>;<\/span><\/p>\n

        memset<\/span>(<\/span>&<\/span>msg,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>msg)<\/span>)<\/span>;<\/span>
        \n msg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
        \n msg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

        \/\/ \u4ece\u5185\u6838\u63a5\u6536\u6d88\u606f<\/span>
        \n printf<\/span>(<\/span>"waiting for…\\\\n"<\/span>)<\/span>;<\/span>
        \n recvmsg<\/span>(<\/span>sock_fd,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span>
        \n printf<\/span>(<\/span>"Received message: %s \\\\n"<\/span>,<\/span> NLMSG_DATA<\/span>(<\/span>nlh)<\/span>)<\/span>;<\/span><\/p>\n

        close<\/span>(<\/span>sock_fd)<\/span>;<\/span><\/p>\n

        return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \u8bf4\u660e<\/h4>\n

        \u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\u7684\u6574\u4f53\u903b\u8f91\u4e0e\u524d\u6587\u4fdd\u6301\u4e00\u81f4，\u5dee\u5f02\u5728\u4e8e nl_groups \u5b57\u6bb5\u7684\u8bbe\u7f6e，\u8be5\u5b57\u6bb5\u7684\u76f8\u5173\u6587\u6863\u8f83\u4e3a\u7a00\u7f3a，\u5176\u8be6\u7ec6\u7528\u6cd5\u53ef\u901a\u8fc7\u67e5\u9605\u5185\u6838\u6e90\u7801\u4e0e\u76f8\u5173\u6280\u672f\u8d44\u6599\u8fdb\u4e00\u6b65\u83b7\u53d6\u3002<\/p>\n

        \u5185\u6838\u7a7a\u95f4\u4ee3\u7801<\/h4>\n

        #<\/span>include<\/span> <linux\/kernel.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/module.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/skbuff.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/init.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/ip.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/types.h><\/span><\/span>
        \n#<\/span>include<\/span> <linux\/sched.h><\/span><\/span>
        \n#<\/span>include<\/span> <net\/sock.h><\/span><\/span>
        \n#<\/span>include<\/span> <net\/netlink.h><\/span><\/span><\/p>\n

        MODULE_LICENSE<\/span>(<\/span>"GPL"<\/span>)<\/span>;<\/span>
        \nMODULE_AUTHOR<\/span>(<\/span>"Koorey King"<\/span>)<\/span>;<\/span><\/p>\n

        #<\/span>define<\/span> MAX_MSGSIZE<\/span> 1024<\/span> <\/span>\/* \u6d88\u606f\u6700\u5927\u957f\u5ea6\u4e3a 1024 \u5b57\u8282 *\/<\/span><\/span><\/p>\n

        struct<\/span> sock<\/span> *<\/span>nl_sk =<\/span> NULL<\/span>;<\/span>
        \nstatic<\/span> struct<\/span> task_struct<\/span> *<\/span>mythread =<\/span> NULL<\/span>;<\/span> \/\/ \u5185\u6838\u7ebf\u7a0b\u5bf9\u8c61<\/span><\/p>\n

        \/\/ \u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6d88\u606f\u7684\u63a5\u53e3\u51fd\u6570<\/span>
        \nvoid<\/span> sendnlmsg<\/span>(<\/span>char<\/span> *<\/span>message)<\/span>
        \n{<\/span>
        \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span>
        \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh;<\/span>
        \n int<\/span> len =<\/span> NLMSG_SPACE<\/span>(<\/span>MAX_MSGSIZE)<\/span>;<\/span>
        \n int<\/span> slen =<\/span> 0<\/span>;<\/span><\/p>\n

        if<\/span>(<\/span>!<\/span>message ||<\/span> !<\/span>nl_sk)<\/span>{<\/span>
        \n return<\/span>;<\/span>
        \n }<\/span><\/p>\n

        \/\/ \u4e3a\u65b0\u7684 sk_buffer \u7533\u8bf7\u7a7a\u95f4<\/span>
        \n skb =<\/span> alloc_skb<\/span>(<\/span>len,<\/span> GFP_KERNEL)<\/span>;<\/span>
        \n if<\/span>(<\/span>!<\/span>skb)<\/span>{<\/span>
        \n printk<\/span>(<\/span>KERN_ERR "my_net_link: alloc_skb Error.\/n"<\/span>)<\/span>;<\/span>
        \n return<\/span>;<\/span>
        \n }<\/span><\/p>\n

        slen =<\/span> strlen<\/span>(<\/span>message)<\/span>+<\/span>1<\/span>;<\/span><\/p>\n

        \/\/ \u7528 nlmsg_put() \u6765\u8bbe\u7f6e netlink \u6d88\u606f\u5934\u90e8<\/span>
        \n nlh =<\/span> nlmsg_put<\/span>(<\/span>skb,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> MAX_MSGSIZE,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u8bbe\u7f6e Netlink \u7684\u63a7\u5236\u5757\u91cc\u7684\u76f8\u5173\u4fe1\u606f<\/span>
        \n NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>pid =<\/span> 0<\/span>;<\/span> \/\/ \u6d88\u606f\u53d1\u9001\u8005\u4e3a\u5185\u6838\u7a7a\u95f4，\u7f6e\u4e3a 0<\/span>
        \n NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>dst_group =<\/span> 5<\/span>;<\/span> \/\/ \u591a\u64ad\u7ec4\u53f7\u4e3a 5<\/span><\/p>\n

        message[<\/span>slen]<\/span> =<\/span> '\\\\0'<\/span>;<\/span>
        \n memcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>,<\/span> message,<\/span> slen+<\/span>1<\/span>)<\/span>;<\/span><\/p>\n

        \/\/ \u53d1\u9001\u591a\u64ad\u6d88\u606f\u5230\u591a\u64ad\u7ec4 5<\/span>
        \n netlink_broadcast<\/span>(<\/span>nl_sk,<\/span> skb,<\/span> 0<\/span>,<\/span>5<\/span>,<\/span> GFP_KERNEL)<\/span>;<\/span>
        \n printk<\/span>(<\/span>"send OK!\\\\n"<\/span>)<\/span>;<\/span>
        \n return<\/span>;<\/span>
        \n}<\/span><\/p>\n

        \/\/ \u5185\u6838\u7ebf\u7a0b\u51fd\u6570：\u6bcf\u9694 1 \u79d2\u949f\u53d1\u9001\u4e00\u6761\u201cI am from kernel!\u201d\u6d88\u606f，\u5171\u53d1\u9001 10 \u6761<\/span>
        \nstatic<\/span> int<\/span> sending_thread<\/span>(<\/span>void<\/span> *<\/span>data)<\/span>
        \n{<\/span>
        \n int<\/span> i =<\/span> 10<\/span>;<\/span>
        \n struct<\/span> completion<\/span> cmpl;<\/span><\/p>\n

        while<\/span>(<\/span>i—<\/span>)<\/span>{<\/span>
        \n init_completion<\/span>(<\/span>&<\/span>cmpl)<\/span>;<\/span>
        \n wait_for_completion_timeout<\/span>(<\/span>&<\/span>cmpl,<\/span> 1<\/span> *<\/span> HZ)<\/span>;<\/span>
        \n sendnlmsg<\/span>(<\/span>"I am from kernel!"<\/span>)<\/span>;<\/span>
        \n }<\/span>
        \n printk<\/span>(<\/span>"sending thread exited!"<\/span>)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> int<\/span> __init myinit_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n printk<\/span>(<\/span>"my netlink in\\\\n"<\/span>)<\/span>;<\/span>
        \n nl_sk =<\/span> netlink_kernel_create<\/span>(<\/span>NETLINK_TEST,<\/span>0<\/span>,<\/span>NULL<\/span>,<\/span>THIS_MODULE)<\/span>;<\/span><\/p>\n

        if<\/span>(<\/span>!<\/span>nl_sk)<\/span>{<\/span>
        \n printk<\/span>(<\/span>KERN_ERR "my_net_link: create netlink socket error.\\\\n"<\/span>)<\/span>;<\/span>
        \n return<\/span> 1<\/span>;<\/span>
        \n }<\/span><\/p>\n

        printk<\/span>(<\/span>"my netlink: create netlink socket ok.\\\\n"<\/span>)<\/span>;<\/span>
        \n mythread =<\/span> kthread_run<\/span>(<\/span>sending_thread,<\/span>NULL<\/span>,<\/span>"thread_sender"<\/span>)<\/span>;<\/span>
        \n return<\/span> 0<\/span>;<\/span>
        \n}<\/span><\/p>\n

        static<\/span> void<\/span> __exit mycleanup_module<\/span>(<\/span>)<\/span>
        \n{<\/span>
        \n if<\/span>(<\/span>nl_sk !=<\/span> NULL<\/span>)<\/span>{<\/span>
        \n sock_release<\/span>(<\/span>nl_sk-><\/span>sk_socket)<\/span>;<\/span>
        \n }<\/span>
        \n printk<\/span>(<\/span>"my netlink out!\\\\n"<\/span>)<\/span>;<\/span>
        \n}<\/span><\/p>\n

        module_init<\/span>(<\/span>myinit_module)<\/span>;<\/span>
        \nmodule_exit<\/span>(<\/span>mycleanup_module)<\/span>;<\/span><\/p>\n

        \u8865\u5145\u8bf4\u660e<\/h3>\n
      • \u5185\u6838\u51fd\u6570 netlink_kernel_create(int unit, unsigned int groups,\u2026) \u7684\u7b2c\u4e8c\u4e2a\u53c2\u6570，\u8868\u793a\u5185\u6838\u8fdb\u7a0b\u6700\u591a\u80fd\u5904\u7406\u7684\u591a\u64ad\u7ec4\u4e2a\u6570，\u82e5\u8be5\u503c\u5c0f\u4e8e \n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span>，\u5219\u9ed8\u8ba4\u6309 <\/p>\n

        32 <\/p>\n

        32 <\/p>\n

        <\/span><\/span>32<\/span><\/span><\/span><\/span><\/span> \u5904\u7406\u3002\u56e0\u6b64，\u8c03\u7528\u8be5\u51fd\u6570\u65f6，\u901a\u5e38\u53ef\u5c06\u7b2c\u4e8c\u4e2a\u53c2\u6570\u7f6e\u4e3a <\/p>\n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>\u3002<\/li>\n

      • struct sk_buff \u7ed3\u6784\u4f53\u4e2d\u7684 cb[48] \u5b57\u6bb5\u4e3a\u63a7\u5236\u7f13\u51b2\u533a，\u53ef\u4f9b\u5404\u5c42\u534f\u8bae\u5b58\u50a8\u79c1\u6709\u53d8\u91cf，Netlink \u673a\u5236\u901a\u8fc7\u5c06\u8be5\u5b57\u6bb5\u5f3a\u5236\u8f6c\u6362\u4e3a struct netlink_skb_parms{} \u7ed3\u6784\u4f53，\u586b\u5145 Netlink \u901a\u4fe1\u6240\u9700\u7684\u79c1\u6709\u4fe1\u606f，\u5176\u56fa\u5b9a\u586b\u5145\u6a21\u677f\u5982\u4e0b：NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>pid=<\/span>xx;<\/span>
        \nNETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>dst_group=<\/span>xx;<\/span>\n <\/li>\n
      • \u672c\u6b21\u5b9e\u9a8c\u4e2d，\u5c06 NETLINK_CB(skb).dst_group \u8bbe\u7f6e\u4e3a\u5bf9\u5e94\u591a\u64ad\u7ec4\u53f7\u6216 \n

        0 <\/p>\n

        0 <\/p>\n

        <\/span><\/span>0<\/span><\/span><\/span><\/span><\/span>，\u7528\u6237\u7a7a\u95f4\u5747\u80fd\u6536\u5230\u591a\u64ad\u6d88\u606f，\u5176\u5e95\u5c42\u539f\u56e0\u9700\u8fdb\u4e00\u6b65\u67e5\u9605\u5185\u6838\u6e90\u7801\u4e0e\u6df1\u5165\u5206\u6790 Netlink \u591a\u64ad\u673a\u5236\u5b9e\u73b0\u539f\u7406\u3002<\/li>\n

        \u6d4b\u8bd5\u4e0e\u6ce8\u610f\u4e8b\u9879<\/h3>\n
      • \u7f16\u8bd1\u5b8c\u6210\u540e，\u9700\u5148\u6267\u884c insmod \u547d\u4ee4\u52a0\u8f7d\u5185\u6838\u6a21\u5757，\u518d\u8fd0\u884c\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\u3002\u82e5\u672a\u52a0\u8f7d mynlkern.ko \u5185\u6838\u6a21\u5757\u800c\u76f4\u63a5\u8fd0\u884c .\/test 5，bind() \u7cfb\u7edf\u8c03\u7528\u5c06\u8fd4\u56de No such file or directory \u9519\u8bef\u3002<\/li>\n
      • \u90e8\u5206\u8001\u7248\u672c Netlink \u591a\u64ad\u6559\u7a0b\u4e2d\u63d0\u53ca\u7684\u201c\u5148\u8fd0\u884c\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f，\u518d\u52a0\u8f7d\u5185\u6838\u6a21\u5757\u201d\u7684\u65b9\u5f0f，\u5728\u5185\u6838 2.6.21 \u7248\u672c\u4e2d\u5df2\u4e0d\u518d\u9002\u7528，\u9700\u91cd\u70b9\u6ce8\u610f\u3002<\/li>\n

        \u5c0f\u7ed3<\/h3>\n

        \u901a\u8fc7\u4e09\u7bc7\u5185\u5bb9\u7684\u9610\u8ff0，<\/p>\n

      • \u660e\u786e\u4e86 Netlink \u7684\u5173\u952e\u7279\u6027（\u65e0\u8fde\u63a5\u3001\u57fa\u4e8e BSD Socket\u3001\u652f\u6301\u5355\u64ad\/\u591a\u64ad）\u3001\u6d88\u606f\u683c\u5f0f（16 \u5b57\u8282\u56fa\u5b9a\u5934+\u53ef\u53d8\u8d1f\u8f7d）\u4e0e\u7f16\u7a0b\u5173\u952e\u8981\u70b9（pid \u5b57\u6bb5\u53d6\u503c\u3001\u591a\u64ad\u7ec4\u53f7\u4e0e\u63a9\u7801\u8f6c\u6362\u3001bind() \u8c03\u7528\u7684\u9002\u7528\u573a\u666f）；<\/li>\n
      • \u68b3\u7406\u4e86 Netlink \u7f16\u7a0b\u7684\u4e09\u4e2a\u9636\u6bb5（\u5355\u5411\u901a\u4fe1\u3001\u53cc\u5411\u901a\u4fe1\u3001\u65e0 bind() \u901a\u4fe1）\u4e0e\u591a\u64ad\u673a\u5236\u7684\u5b9e\u73b0\u6d41\u7a0b，\u8865\u5145\u4e86\u5b9e\u9a8c\u6ce8\u610f\u4e8b\u9879\u4e0e\u540e\u7eed\u6df1\u5165\u5b66\u4e60\u7684\u65b9\u5411；<\/li>\n

        \u53ef\u5bf9 Netlink \u673a\u5236\u5f62\u6210\u521d\u6b65\u8ba4\u77e5，\u5e76\u80fd\u591f\u5f00\u53d1\u57fa\u4e8e Netlink \u7684\u57fa\u7840\u5e94\u7528\u7a0b\u5e8f\u3002\u4f46\u8fd9\u4ec5\u4e3a\u8be5\u673a\u5236\u7684\u5165\u95e8\u5185\u5bb9，\u82e5\u8981\u5f00\u53d1\u9ad8\u8d28\u91cf\u3001\u9ad8\u6548\u7387\u7684 Netlink \u5e94\u7528\u6a21\u5757，\u8fd8\u9700\u8fdb\u4e00\u6b65\u6df1\u5165\u7406\u89e3\u5176\u5e95\u5c42\u672c\u8d28，\u540c\u65f6\u638c\u63e1\u5185\u6838\u7f16\u7a0b\u7684\u76f8\u5173\u57fa\u7840\u80fd\u529b，\u4f8b\u5982\u4e34\u754c\u8d44\u6e90\u7684\u4e92\u65a5\u4fdd\u62a4\u3001\u7ebf\u7a0b\u5b89\u5168\u6027\u4fdd\u969c\u3001\u5927\u6570\u636e\u91cf\u4f20\u8f93\u7684\u5904\u7406\u7b56\u7565\u7b49，\u8fd9\u4e9b\u5747\u4e3a\u5b9e\u9645\u5f00\u53d1\u4e2d\u9700\u8981\u91cd\u70b9\u8003\u8651\u7684\u95ee\u9898\u3002<\/p>\n

        \n

        Linux \u5185\u6838\u4e0e\u7528\u6237\u7a7a\u95f4\u901a\u4fe1\u4e4b Netlink \u4f7f\u7528\u65b9\u6cd5<\/h2>\n

        HAOMCU \u8f6c\u8f7d\u65f6\u95f4：2012-03-20 09:41:52<\/p>\n

        1 \u7b80\u4ecb<\/h3>\n

        \u672c\u6587\u4ecb\u7ecd Linux \u5185\u6838\u4e2d\u7684 Netlink \u901a\u4fe1\u673a\u5236，\u8be6\u7ec6\u9610\u8ff0 Netlink \u7684\u5de5\u4f5c\u539f\u7406\u4e0e\u6280\u672f\u4f18\u52bf，\u5305\u62ec\u5176\u652f\u6301\u7684\u591a\u79cd\u534f\u8bae\u7c7b\u578b\u3001\u5f02\u6b65\u901a\u4fe1\u673a\u5236\u53ca\u591a\u64ad\u7279\u6027，\u5e76\u901a\u8fc7\u5b9e\u4f8b\u5c55\u793a\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u7684\u901a\u4fe1\u8fc7\u7a0b\u3002<\/p>\n

        Linux \u4e2d\u7684\u8fdb\u7a0b\u95f4\u901a\u4fe1\u673a\u5236\u6e90\u81ea Unix \u5e73\u53f0\u7684\u8fdb\u7a0b\u901a\u4fe1\u673a\u5236\u3002Unix \u7684\u4e24\u5927\u5206\u652f AT&T Unix \u548c BSD Unix \u5728\u8fdb\u7a0b\u901a\u4fe1\u5b9e\u73b0\u673a\u5236\u4e0a\u5b58\u5728\u5dee\u5f02：\u524d\u8005\u5f62\u6210\u9002\u7528\u4e8e\u5355\u53f0\u8ba1\u7b97\u673a\u7684 System V IPC，\u540e\u8005\u5b9e\u73b0\u57fa\u4e8e Socket \u7684\u8fdb\u7a0b\u95f4\u901a\u4fe1\u673a\u5236\u3002\u540c\u65f6，Linux \u9075\u5faa IEEE \u5236\u5b9a\u7684 Posix IPC \u6807\u51c6，\u5728\u4e0a\u8ff0\u4e09\u7c7b\u673a\u5236\u57fa\u7840\u4e0a\u5b9e\u73b0\u4ee5\u4e0b\u4e3b\u8981 IPC \u673a\u5236：\u7ba1\u9053（Pipe）\u53ca\u547d\u540d\u7ba1\u9053（Named Pipe）\u3001\u4fe1\u53f7（Signal）\u3001\u6d88\u606f\u961f\u5217（Message queue）\u3001\u5171\u4eab\u5185\u5b58（Shared Memory）\u3001\u4fe1\u53f7\u91cf（Semaphore）\u3001\u5957\u63a5\u5b57（Socket）\u3002\u501f\u52a9\u8fd9\u4e9b IPC \u673a\u5236，\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u95f4\u53ef\u5b8c\u6210\u6570\u636e\u4ea4\u4e92\u3002\u4e3a\u5b9e\u73b0\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u7684\u901a\u4fe1，Linux \u63d0\u4f9b\u57fa\u4e8e Socket \u7684 Netlink \u901a\u4fe1\u673a\u5236，\u53ef\u5b9e\u73b0\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u4e4b\u95f4\u6570\u636e\u7684\u5b9e\u65f6\u4ea4\u4e92\u3002<\/p>\n

        \u672c\u6587\u7b2c 2 \u8282\u6982\u8ff0\u76f8\u5173\u7814\u7a76\u5de5\u4f5c，\u7b2c 3 \u8282\u5bf9\u6bd4\u5176\u4ed6 IPC \u673a\u5236，\u8be6\u7ec6\u4ecb\u7ecd Netlink \u673a\u5236\u53ca\u5176\u5173\u952e\u6280\u672f，\u7b2c 4 \u8282\u91c7\u7528 KGDB+GDB \u7ec4\u5408\u8c03\u8bd5\u65b9\u5f0f，\u901a\u8fc7\u793a\u4f8b\u7a0b\u5e8f\u6f14\u793a Netlink \u901a\u4fe1\u8fc7\u7a0b，\u7b2c 5 \u8282\u603b\u7ed3\u5e76\u6307\u51fa Netlink \u901a\u4fe1\u673a\u5236\u7684\u4e0d\u8db3\u4e4b\u5904\u3002<\/p>\n

        2 \u76f8\u5173\u7814\u7a76<\/h4>\n

        \u622a\u81f3\u76ee\u524d，Linux \u63d0\u4f9b 9 \u79cd\u5b9e\u73b0\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u6570\u636e\u4ea4\u6362\u7684\u673a\u5236，\u5206\u522b\u4e3a\u5185\u6838\u542f\u52a8\u53c2\u6570\u3001\u6a21\u5757\u53c2\u6570\u4e0e sysfs\u3001sysctl\u3001\u7cfb\u7edf\u8c03\u7528\u3001netlink\u3001procfs\u3001seq_file\u3001debugfs \u548c relayfs\u3002\u5176\u4e2d，\u6a21\u5757\u53c2\u6570\u4e0e sysfs\u3001procfs\u3001debugfs\u3001relayfs \u5c5e\u4e8e\u57fa\u4e8e\u6587\u4ef6\u7cfb\u7edf\u7684\u901a\u4fe1\u673a\u5236，\u4e3b\u8981\u7528\u4e8e\u5185\u6838\u7a7a\u95f4\u5411\u7528\u6237\u7a7a\u95f4\u8f93\u51fa\u4fe1\u606f；sysctl\u3001\u7cfb\u7edf\u8c03\u7528\u4e3a\u7528\u6237\u7a7a\u95f4\u53d1\u8d77\u7684\u901a\u4fe1\u673a\u5236\u3002\u7531\u6b64\u53ef\u89c1，\u4e0a\u8ff0\u673a\u5236\u5747\u4e3a\u5355\u5de5\u901a\u4fe1\u673a\u5236，\u5728\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u7684\u53cc\u5411\u4ea4\u4e92\u5f0f\u6570\u636e\u4ea4\u6362\u573a\u666f\u4e0b\u5b58\u5728\u4e00\u5b9a\u7684\u5c40\u9650\u6027\u3002<\/p>\n

        Netlink \u662f\u57fa\u4e8e Socket \u7684\u901a\u4fe1\u673a\u5236，\u4f9d\u6258 Socket \u672c\u8eab\u5177\u5907\u7684\u53cc\u5411\u6027\u3001\u7a81\u53d1\u6027\u3001\u975e\u963b\u585e\u7279\u6027，\u80fd\u591f\u8f83\u597d\u5730\u6ee1\u8db3\u5185\u6838\u7a7a\u95f4\u4e0e\u7528\u6237\u7a7a\u95f4\u5c0f\u91cf\u6570\u636e\u7684\u5b9e\u65f6\u4ea4\u4e92\u9700\u6c42，\u56e0\u6b64\u5728 Linux 2.6 \u5185\u6838\u4e2d\u88ab\u5e7f\u6cdb\u5e94\u7528\u3002\u4f8b\u5982 SELinux \u7ec4\u4ef6，\u4ee5\u53ca Linux \u7cfb\u7edf\u9632\u706b\u5899\u7684\u5185\u6838\u6001\u7ec4\u4ef6 netfilter \u4e0e\u7528\u6237\u6001\u7ec4\u4ef6 iptables \u4e4b\u95f4\u7684\u6570\u636e\u4ea4\u6362，\u5747\u901a\u8fc7 Netlink \u673a\u5236\u5b8c\u6210\u3002<\/p>\n

        3 Netlink \u673a\u5236\u53ca\u5176\u5173\u952e\u6280\u672f<\/h4>\n

        3.1 Netlink \u673a\u5236<\/h6>\n

        \u5728 Linux \u64cd\u4f5c\u7cfb\u7edf\u4e2d，CPU \u5904\u4e8e\u5185\u6838\u6001\u65f6\u53ef\u5206\u4e3a\u4e24\u79cd\u573a\u666f：\u5b58\u5728\u7528\u6237\u4e0a\u4e0b\u6587\u7684\u72b6\u6001\u3001\u6267\u884c\u786c\u4ef6\u4e2d\u65ad\u6216\u8f6f\u4ef6\u4e2d\u65ad\u7684\u72b6\u6001\u3002\u5176\u4e2d，\u5728\u5b58\u5728\u7528\u6237\u4e0a\u4e0b\u6587\u7684\u573a\u666f\u4e0b，\u7531\u4e8e\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u7684\u5185\u5b58\u6620\u5c04\u673a\u5236\u4e0d\u540c，\u65e0\u6cd5\u76f4\u63a5\u5c06\u672c\u5730\u53d8\u91cf\u4f20\u9012\u81f3\u7528\u6237\u6001\u5185\u5b58\u533a\u57df；\u5728\u6267\u884c\u786c\u4ef6\u4e2d\u65ad\u6216\u8f6f\u4ef6\u4e2d\u65ad\u7684\u573a\u666f\u4e0b，\u4ee3\u7801\u6267\u884c\u8fc7\u7a0b\u4e0d\u53ef\u4e2d\u65ad，\u540c\u6837\u65e0\u6cd5\u76f4\u63a5\u5411\u7528\u6237\u5185\u5b58\u533a\u57df\u4f20\u9012\u6570\u636e\u3002<\/p>\n

        \u4f20\u7edf\u8fdb\u7a0b\u95f4\u901a\u4fe1\u673a\u5236\u5747\u65e0\u6cd5\u76f4\u63a5\u5e94\u7528\u4e8e\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u4e4b\u95f4\u7684\u901a\u4fe1，\u5177\u4f53\u539f\u56e0\u5982\u8868 1 \u6240\u793a：<\/p>\n\n\u901a\u4fe1\u65b9\u6cd5\u65e0\u6cd5\u5e94\u7528\u4e8e\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u7684\u539f\u56e0<\/tr>\n\n\n\n\n\n\n
        \u7ba1\u9053（\u4e0d\u542b\u547d\u540d\u7ba1\u9053）<\/td>\n\u4ec5\u652f\u6301\u7236\u5b50\u8fdb\u7a0b\u95f4\u7684\u901a\u4fe1<\/td>\n<\/tr>\n
        \u6d88\u606f\u961f\u5217<\/td>\n\u65e0\u6cd5\u5728\u786c\u4ef6\u4e2d\u65ad\u3001\u8f6f\u4ef6\u4e2d\u65ad\u4e2d\u65e0\u963b\u585e\u63a5\u6536\u6570\u636e<\/td>\n<\/tr>\n
        \u4fe1\u53f7\u91cf<\/td>\n\u65e0\u6cd5\u8de8\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u4f7f\u7528<\/td>\n<\/tr>\n
        \u5171\u4eab\u5185\u5b58<\/td>\n\u9700\u4fe1\u53f7\u91cf\u8f85\u52a9\u5b9e\u73b0\u540c\u6b65，\u800c\u4fe1\u53f7\u91cf\u65e0\u6cd5\u8de8\u6001\u4f7f\u7528<\/td>\n<\/tr>\n
        \u5957\u63a5\u5b57<\/td>\n\u65e0\u6cd5\u5728\u786c\u4ef6\u4e2d\u65ad\u3001\u8f6f\u4ef6\u4e2d\u65ad\u4e2d\u65e0\u963b\u585e\u63a5\u6536\u6570\u636e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        \u8868 1（\u5f15\u81ea \u53c2\u8003\u6587\u732e 5）<\/p>\n

        \u89e3\u51b3\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u901a\u4fe1\u95ee\u9898\u7684\u65b9\u6848\u53ef\u5206\u4e3a\u4e24\u7c7b：<\/p>\n

      • \u5b58\u5728\u7528\u6237\u4e0a\u4e0b\u6587\u65f6，\u53ef\u8c03\u7528 Linux \u63d0\u4f9b\u7684 copy_from_user() \u548c copy_to_user() \u51fd\u6570\u5b8c\u6210\u6570\u636e\u4f20\u8f93，\u4f46\u8fd9\u4e24\u4e2a\u51fd\u6570\u53ef\u80fd\u4ea7\u751f\u963b\u585e，\u56e0\u6b64\u65e0\u6cd5\u5728\u786c\u4ef6\u4e2d\u65ad\u3001\u8f6f\u4ef6\u4e2d\u65ad\u8fc7\u7a0b\u4e2d\u8c03\u7528；<\/li>\n
      • \u6267\u884c\u786c\u4ef6\u4e2d\u65ad\u6216\u8f6f\u4ef6\u4e2d\u65ad\u65f6，\u53ef\u901a\u8fc7\u4ee5\u4e0b\u4e24\u79cd\u65b9\u5f0f\u5b9e\u73b0： 2.1 \u501f\u52a9 Linux \u5185\u6838\u63d0\u4f9b\u7684 spinlock \u81ea\u65cb\u9501\u5b9e\u73b0\u5185\u6838\u7ebf\u7a0b\u4e0e\u4e2d\u65ad\u8fc7\u7a0b\u7684\u540c\u6b65\u3002\u7531\u4e8e\u5185\u6838\u7ebf\u7a0b\u8fd0\u884c\u5728\u6709\u4e0a\u4e0b\u6587\u7684\u8fdb\u7a0b\u73af\u5883\u4e2d，\u56e0\u6b64\u53ef\u5728\u5185\u6838\u7ebf\u7a0b\u4e2d\u901a\u8fc7\u5957\u63a5\u5b57\u6216\u6d88\u606f\u961f\u5217\u83b7\u53d6\u7528\u6237\u7a7a\u95f4\u6570\u636e，\u518d\u901a\u8fc7\u4e34\u754c\u533a\u5c06\u6570\u636e\u4f20\u9012\u81f3\u4e2d\u65ad\u8fc7\u7a0b； 2.2 \u57fa\u4e8e Netlink \u673a\u5236\u5b9e\u73b0\u3002Netlink \u5957\u63a5\u5b57\u7684\u901a\u4fe1\u6807\u8bc6\u901a\u5e38\u4e3a\u8fdb\u7a0b\u7684 ID（\u8fdb\u7a0b\u6807\u8bc6\u7b26）\u3002Netlink \u901a\u4fe1\u7684\u663e\u8457\u7279\u5f81\u662f\u5bf9\u4e2d\u65ad\u8fc7\u7a0b\u7684\u826f\u597d\u652f\u6301：\u5185\u6838\u7a7a\u95f4\u63a5\u6536\u7528\u6237\u7a7a\u95f4\u6570\u636e\u65f6，\u65e0\u9700\u7528\u6237\u81ea\u884c\u542f\u52a8\u5185\u6838\u7ebf\u7a0b，\u800c\u662f\u901a\u8fc7\u8f6f\u4e2d\u65ad\u8c03\u7528\u7528\u6237\u9884\u5148\u6307\u5b9a\u7684\u63a5\u6536\u51fd\u6570\u3002\u8fd9\u79cd\u57fa\u4e8e\u8f6f\u4e2d\u65ad\u7684\u5b9e\u73b0\u65b9\u5f0f\u76f8\u8f83\u4e8e\u81ea\u884c\u542f\u52a8\u5185\u6838\u7ebf\u7a0b，\u80fd\u591f\u4fdd\u969c\u6570\u636e\u4f20\u8f93\u7684\u5b9e\u65f6\u6027\u3002<\/li>\n
        3.2 Netlink \u4f18\u52bf<\/h6>\n

        \u76f8\u8f83\u4e8e\u5176\u4ed6\u901a\u4fe1\u673a\u5236，Netlink \u5177\u5907\u4ee5\u4e0b\u4f18\u52bf：<\/p>\n

      • \u57fa\u4e8e Netlink \u81ea\u5b9a\u4e49\u65b0\u534f\u8bae\u5e76\u52a0\u5165\u534f\u8bae\u65cf\u540e，\u5373\u53ef\u901a\u8fc7 Socket API \u5b8c\u6210\u6570\u636e\u4ea4\u6362；\u800c ioctl \u548c proc \u6587\u4ef6\u7cfb\u7edf\u9700\u901a\u8fc7\u7a0b\u5e8f\u65b0\u589e\u5bf9\u5e94\u7684\u8bbe\u5907\u6216\u6587\u4ef6\u624d\u80fd\u5b9e\u73b0\u901a\u4fe1；<\/li>\n
      • Netlink \u91c7\u7528 Socket \u7f13\u5b58\u961f\u5217\u5b9e\u73b0\u5f02\u6b65\u901a\u4fe1，\u800c ioctl \u4e3a\u540c\u6b65\u901a\u4fe1\u673a\u5236，\u82e5\u4f20\u8f93\u6570\u636e\u91cf\u8f83\u5927，\u6613\u964d\u4f4e\u7cfb\u7edf\u6027\u80fd；<\/li>\n
      • Netlink \u652f\u6301\u591a\u64ad\u7279\u6027，\u5f52\u5c5e\u540c\u4e00 Netlink \u7ec4\u7684\u6a21\u5757\u4e0e\u8fdb\u7a0b\u5747\u53ef\u63a5\u6536\u8be5\u7ec4\u7684\u591a\u64ad\u6d88\u606f；<\/li>\n
      • Netlink \u5141\u8bb8\u5185\u6838\u4e3b\u52a8\u53d1\u8d77\u4f1a\u8bdd，\u800c ioctl \u4e0e\u7cfb\u7edf\u8c03\u7528\u4ec5\u80fd\u7531\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u53d1\u8d77\u3002<\/li>\n

        \u5185\u6838\u6e90\u7801\u4e2d\u5173\u4e8e Netlink \u534f\u8bae\u7684\u5934\u6587\u4ef6\u5b9a\u4e49\u4e86\u9884\u5b9a\u4e49\u534f\u8bae\u7c7b\u578b，\u5177\u4f53\u5982\u4e0b：<\/p>\n

        #<\/span>define<\/span> NETLINK_ROUTE<\/span> 0<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_W1<\/span> 1<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_USERSOCK<\/span> 2<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIREWALL<\/span> 3<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_INET_DIAG<\/span> 4<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NFLOG<\/span> 5<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_XFRM<\/span> 6<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_SELINUX<\/span> 7<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_ISCSI<\/span> 8<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_AUDIT<\/span> 9<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_FIB_LOOKUP<\/span> 10<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_CONNECTOR<\/span> 11<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_NETFILTER<\/span> 12<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_IP6_FW<\/span> 13<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_DNRTMSG<\/span> 14<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_KOBJECT_UEVENT<\/span> 15<\/span><\/span><\/span>
        \n#<\/span>define<\/span> NETLINK_GENERIC<\/span> 16<\/span><\/span><\/span><\/p>\n

        \u4e0a\u8ff0\u534f\u8bae\u5df2\u9002\u914d\u4e0d\u540c\u7684\u7cfb\u7edf\u5e94\u7528\u573a\u666f，\u6bcf\u79cd\u5e94\u7528\u5747\u6709\u4e13\u5c5e\u7684\u4f20\u8f93\u6570\u636e\u683c\u5f0f\u3002\u82e5\u7528\u6237\u65e0\u9700\u4f7f\u7528\u8fd9\u4e9b\u9884\u5b9a\u4e49\u534f\u8bae，\u53ef\u65b0\u589e\u81ea\u5b9a\u4e49\u534f\u8bae\u53f7\u3002\u9488\u5bf9\u6bcf\u4e2a Netlink \u534f\u8bae\u7c7b\u578b，\u6700\u591a\u53ef\u8bbe\u7f6e 32 \u4e2a\u591a\u64ad\u7ec4，\u6bcf\u4e2a\u591a\u64ad\u7ec4\u7531 1 \u4e2a\u6bd4\u7279\u4f4d\u6807\u8bc6\u3002Netlink \u7684\u591a\u64ad\u7279\u6027\u4f7f\u5f97\u5411\u540c\u4e00\u7ec4\u53d1\u9001\u6d88\u606f\u4ec5\u9700\u4e00\u6b21\u7cfb\u7edf\u8c03\u7528，\u5bf9\u4e8e\u9700\u4f20\u8f93\u591a\u64ad\u6d88\u606f\u7684\u5e94\u7528\u800c\u8a00，\u53ef\u663e\u8457\u964d\u4f4e\u7cfb\u7edf\u8c03\u7528\u6b21\u6570\u3002<\/p>\n

        \u5efa\u7acb Netlink \u4f1a\u8bdd\u7684\u6d41\u7a0b\u5982\u4e0b： \"img\"<\/p>\n

        \u5185\u6838\u901a\u8fc7\u4e00\u5957\u4e0e\u6807\u51c6 Socket API \u76f8\u4f3c\u7684\u63a5\u53e3\u5b8c\u6210\u901a\u4fe1\u8fc7\u7a0b，\u9996\u5148\u8c03\u7528 netlink_kernel_create() \u521b\u5efa\u5957\u63a5\u5b57，\u8be5\u51fd\u6570\u539f\u578b\u4e3a：<\/p>\n

        struct<\/span> sock<\/span> *<\/span>netlink_kernel_create<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span>
        \nint<\/span> unit,<\/span>unsigned<\/span> int<\/span> groups,<\/span>
        \nvoid<\/span> (<\/span>*<\/span>input)<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>,<\/span>
        \nstruct<\/span> mutex<\/span> *<\/span>cb_mutex,<\/span>
        \nstruct<\/span> module<\/span> *<\/span>module)<\/span>;<\/span><\/p>\n

        \u5176\u4e2d，net \u53c2\u6570\u4e3a\u7f51\u7edc\u8bbe\u5907\u547d\u540d\u7a7a\u95f4\u6307\u9488；input \u51fd\u6570\u4e3a Netlink Socket \u63a5\u6536\u6d88\u606f\u65f6\u89e6\u53d1\u7684\u56de\u8c03\u51fd\u6570\u6307\u9488；module \u53c2\u6570\u9ed8\u8ba4\u503c\u4e3a THIS_MODULE\u3002<\/p>\n

        \u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5219\u901a\u8fc7\u6807\u51c6 Socket API \u521b\u5efa\u5957\u63a5\u5b57，\u5e76\u5c06\u8fdb\u7a0b ID \u53d1\u9001\u81f3\u5185\u6838\u7a7a\u95f4\u3002\u7528\u6237\u7a7a\u95f4\u8c03\u7528 socket() \u521b\u5efa\u5957\u63a5\u5b57，\u51fd\u6570\u539f\u578b\u4e3a：<\/p>\n

        int<\/span> socket<\/span>(<\/span>int<\/span> domain,<\/span> int<\/span> type,<\/span> int<\/span> protocol)<\/span>;<\/span><\/p>\n

        \u5176\u4e2d，domain \u53c2\u6570\u53d6\u503c\u4e3a PF_NETLINK（\u5373 Netlink \u534f\u8bae\u65cf）；protocol \u53c2\u6570\u4e3a Netlink \u9884\u5b9a\u4e49\u534f\u8bae（\u5982 NETLINK_ROUTE\u3001NETLINK_FIREWALL\u3001NETLINK_ARPD\u3001NETLINK_ROUTE6\u3001NETLINK_IP6_FW）\u6216\u7528\u6237\u81ea\u5b9a\u4e49\u534f\u8bae\u3002<\/p>\n

        \u968f\u540e\u8c03\u7528 bind() \u51fd\u6570\u5b8c\u6210\u7ed1\u5b9a\u64cd\u4f5c\u3002Netlink \u7684 bind() \u51fd\u6570\u5c06\u672c\u5730 Socket \u5730\u5740（\u6e90 Socket \u5730\u5740）\u4e0e\u5df2\u6253\u5f00\u7684 Socket \u5173\u8054，\u7ed1\u5b9a\u5b8c\u6210\u4e14\u5185\u6838\u7a7a\u95f4\u63a5\u6536\u7528\u6237\u8fdb\u7a0b ID \u540e，\u5373\u53ef\u5f00\u5c55\u53cc\u5411\u901a\u4fe1\u3002<\/p>\n

        \u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u901a\u8fc7\u6807\u51c6 Socket API \u4e2d\u7684 sendmsg() \u51fd\u6570\u53d1\u9001\u6570\u636e，\u8c03\u7528\u65f6\u9700\u6784\u9020 struct msghdr \u6d88\u606f\u7ed3\u6784\u4e0e nlmsghdr \u6d88\u606f\u5934\u3002Netlink \u6d88\u606f\u4f53\u7531 nlmsghdr \u6d88\u606f\u5934\u548c\u6d88\u606f\u8f7d\u8377（payload）\u7ec4\u6210，\u8f93\u5165\u6d88\u606f\u540e，\u5185\u6838\u4f1a\u8bbf\u95ee nlmsghdr \u6307\u5411\u7684\u7f13\u51b2\u533a\u3002<\/p>\n

        \u5185\u6838\u7a7a\u95f4\u901a\u8fc7\u72ec\u7acb\u521b\u5efa\u7684 sk_buff \u7f13\u51b2\u533a\u53d1\u9001\u6570\u636e，Linux \u5b9a\u4e49\u4ee5\u4e0b\u5b8f\u7528\u4e8e\u7b80\u5316\u7f13\u51b2\u533a\u5730\u5740\u914d\u7f6e： #define \\\\ NETLINK_CB(skb) \\\\ ((struct \\\\ netlink_skb_parms) &((skb)->cb))$$<\/p>\n

        \u7f13\u51b2\u533a\u5b8c\u6210\u6d88\u606f\u5730\u5740\u914d\u7f6e\u540e，\u53ef\u8c03\u7528 netlink_unicast() \u53d1\u9001\u5355\u64ad\u6d88\u606f，\u8be5\u51fd\u6570\u539f\u578b\u4e3a： int netlink_unicast(struct sock *sk, struct sk_buff *skb, u32 pid, int nonblock); \u53c2\u6570\u8bf4\u660e：<\/p>\n

          \n
        • sk：netlink_kernel_create() \u51fd\u6570\u8fd4\u56de\u7684 Socket \u6307\u9488；<\/li>\n
        • skb：\u5b58\u50a8\u5f85\u53d1\u9001\u6d88\u606f\u7684\u7f13\u51b2\u533a，\u5176 data \u5b57\u6bb5\u6307\u5411 Netlink \u6d88\u606f\u7ed3\u6784，\u63a7\u5236\u5757\u4fdd\u5b58\u6d88\u606f\u5730\u5740\u4fe1\u606f（\u53ef\u901a\u8fc7 NETLINK_CB(skb) \u5b8f\u914d\u7f6e）；<\/li>\n
        • pid：\u63a5\u6536\u6d88\u606f\u8fdb\u7a0b\u7684\u8fdb\u7a0b ID；<\/li>\n
        • nonblock：\u51fd\u6570\u662f\u5426\u4e3a\u975e\u963b\u585e\u6a21\u5f0f（\u53d6\u503c 1 \u65f6，\u65e0\u53ef\u7528\u63a5\u6536\u7f13\u5b58\u5219\u7acb\u5373\u8fd4\u56de；\u53d6\u503c 0 \u65f6，\u65e0\u53ef\u7528\u63a5\u6536\u7f13\u5b58\u5219\u8fdb\u5165\u7761\u7720\u72b6\u6001）\u3002<\/li>\n<\/ul>\n

          \u5185\u6838\u6a21\u5757\u6216\u5b50\u7cfb\u7edf\u53ef\u8c03\u7528 netlink_broadcast() \u53d1\u9001\u5e7f\u64ad\u6d88\u606f，\u51fd\u6570\u539f\u578b\u4e3a： void netlink_broadcast(struct sock *sk, struct sk_buff *skb, u32 pid, u32 group, int allocation); \u524d 3 \u4e2a\u53c2\u6570\u4e0e netlink_unicast() \u4e00\u81f4；group \u4e3a\u63a5\u6536\u6d88\u606f\u7684\u591a\u64ad\u7ec4\u6807\u8bc6（\u9700\u5411\u591a\u4e2a\u591a\u64ad\u7ec4\u53d1\u9001\u6d88\u606f\u65f6，\u53d6\u503c\u4e3a\u591a\u4e2a\u7ec4 ID \u7684\u6309\u4f4d\u6216\u7ed3\u679c）；allocation \u4e3a\u5185\u6838\u5185\u5b58\u5206\u914d\u7c7b\u578b（\u5e38\u7528 GFP_ATOMIC \u6216 GFP_KERNEL，\u524d\u8005\u9002\u7528\u4e8e\u539f\u5b50\u4e0a\u4e0b\u6587（\u4e0d\u53ef\u7761\u7720），\u540e\u8005\u9002\u7528\u4e8e\u975e\u539f\u5b50\u4e0a\u4e0b\u6587）\u3002<\/p>\n

          \u63a5\u6536\u6570\u636e\u65f6，\u7a0b\u5e8f\u9700\u7533\u8bf7\u8db3\u591f\u5927\u5c0f\u7684\u5185\u5b58\u7a7a\u95f4，\u4ee5\u5b58\u50a8 Netlink \u6d88\u606f\u5934\u4e0e\u6d88\u606f\u8f7d\u8377，\u968f\u540e\u8c03\u7528\u6807\u51c6\u51fd\u6570 recvmsg() \u63a5\u6536\u6d88\u606f\u3002<\/p>\n

          4 Netlink \u901a\u4fe1\u8fc7\u7a0b<\/h4>\n

          4.1 \u8c03\u8bd5\u73af\u5883\u4e0e\u5de5\u5177<\/h5>\n

          \u8c03\u8bd5\u5e73\u53f0：Vmware 5.5 + Fedora Core 10（\u4e24\u53f0\u4e3b\u673a，\u5206\u522b\u4f5c\u4e3a host \u673a\u4e0e target \u673a）； \u8c03\u8bd5\u5de5\u5177：KGDB+GDB \u7ec4\u5408（Linux \u5185\u6838 2.6.26 \u53ca\u4ee5\u4e0a\u7248\u672c\u5185\u7f6e KGDB \u9009\u9879，\u7f16\u8bd1\u5185\u6838\u65f6\u9700\u542f\u7528\u76f8\u5173\u914d\u7f6e；\u8c03\u8bd5\u65f6 host \u7aef\u4f7f\u7528\u5e26\u7b26\u53f7\u8868\u7684 vmlinz \u5185\u6838，target \u7aef\u901a\u8fc7 GDB \u8c03\u8bd5\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f）\u3002<\/p>\n

          4.2 \u8c03\u8bd5\u7a0b\u5e8f\u5b9e\u73b0<\/h5>\n

          \u8c03\u8bd5\u7a0b\u5e8f\u5206\u4e3a\u5185\u6838\u6a21\u5757\u4e0e\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\u4e24\u90e8\u5206：\u5185\u6838\u6a21\u5757\u52a0\u8f7d\u540e，\u8fd0\u884c\u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f，\u7531\u7528\u6237\u7a7a\u95f4\u53d1\u8d77 Netlink \u4f1a\u8bdd，\u4e0e\u5185\u6838\u6a21\u5757\u5b8c\u6210\u6570\u636e\u4ea4\u6362\u3002<\/p>\n

          4.2.1 \u7528\u6237\u7a7a\u95f4\u7a0b\u5e8f\u5173\u952e\u4ee3\u7801<\/h6>\n

          int<\/span> send_pck_to_kern<\/span>(<\/span>u8 op,<\/span> const<\/span> u8 *<\/span>data,<\/span> u16 data_len)<\/span>
          \n{<\/span>
          \n struct<\/span> user_data_<\/span> *<\/span>pck;<\/span>
          \n int<\/span> ret;<\/span><\/p>\n

          \/\/ \u5206\u914d\u5185\u5b58\u5e76\u521d\u59cb\u5316<\/span>
          \n pck =<\/span> (<\/span>struct<\/span> user_data_<\/span>*<\/span>)<\/span>calloc<\/span>(<\/span>1<\/span>,<\/span> sizeof<\/span>(<\/span>*<\/span>pck)<\/span> +<\/span> data_len)<\/span>;<\/span>
          \n if<\/span>(<\/span>!<\/span>pck)<\/span> {<\/span>
          \n printf<\/span>(<\/span>"calloc in %s failed!!!\\\\n"<\/span>,<\/span> __FUNCTION__)<\/span>;<\/span>
          \n return<\/span> –<\/span>1<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u586b\u5145\u6d88\u606f\u7ed3\u6784\u4f53<\/span>
          \n pck-><\/span>magic_num =<\/span> MAGIC_NUM_RNQ;<\/span>
          \n pck-><\/span>op =<\/span> op;<\/span>
          \n pck-><\/span>data_len =<\/span> data_len;<\/span>
          \n memcpy<\/span>(<\/span>pck-><\/span>data,<\/span> data,<\/span> data_len)<\/span>;<\/span><\/p>\n

          \/\/ \u53d1\u9001\u6570\u636e\u81f3\u5185\u6838<\/span>
          \n ret =<\/span> send_to_kern<\/span>(<\/span>(<\/span>const<\/span> u8*<\/span>)<\/span>pck,<\/span> sizeof<\/span>(<\/span>*<\/span>pck)<\/span> +<\/span> data_len)<\/span>;<\/span>
          \n if<\/span>(<\/span>ret)<\/span>
          \n printf<\/span>(<\/span>"send_to_kern in %s failed!!!\\\\n"<\/span>,<\/span> __FUNCTION__)<\/span>;<\/span><\/p>\n

          \/\/ \u91ca\u653e\u5185\u5b58<\/span>
          \n free<\/span>(<\/span>pck)<\/span>;<\/span>
          \n return<\/span> ret ?<\/span> –<\/span>1<\/span> :<\/span> 0<\/span>;<\/span>
          \n}<\/span><\/p>\n

          static<\/span> void<\/span> recv_from_nl<\/span>(<\/span>)<\/span>
          \n{<\/span>
          \n char<\/span> buf[<\/span>1000<\/span>]<\/span>;<\/span>
          \n int<\/span> len;<\/span>
          \n struct<\/span> iovec<\/span> iov =<\/span> {<\/span>buf,<\/span> sizeof<\/span>(<\/span>buf)<\/span>}<\/span>;<\/span>
          \n struct<\/span> sockaddr_nl<\/span> sa;<\/span>
          \n struct<\/span> msghdr<\/span> msg;<\/span>
          \n struct<\/span> nlmsghdr<\/span> *<\/span>nh;<\/span><\/p>\n

          \/\/ \u521d\u59cb\u5316\u6d88\u606f\u5934<\/span>
          \n memset<\/span>(<\/span>&<\/span>msg,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>msg)<\/span>)<\/span>;<\/span>
          \n msg.<\/span>msg_name =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>&<\/span>sa;<\/span>
          \n msg.<\/span>msg_namelen =<\/span> sizeof<\/span>(<\/span>sa)<\/span>;<\/span>
          \n msg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
          \n msg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

          \/\/ \u63a5\u6536\u5185\u6838\u6d88\u606f<\/span>
          \n len =<\/span> recvmsg<\/span>(<\/span>nl_sock,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

          \/\/ \u89e3\u6790\u63a5\u6536\u5230\u7684\u6d88\u606f<\/span>
          \n for<\/span> (<\/span>nh =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>buf;<\/span> NLMSG_OK<\/span>(<\/span>nh,<\/span> len)<\/span>;<\/span> nh =<\/span> NLMSG_NEXT<\/span> (<\/span>nh,<\/span> len)<\/span>)<\/span> {<\/span>
          \n \/\/ \u591a\u6bb5\u6d88\u606f\u7ed3\u675f\u6807\u8bc6<\/span>
          \n if<\/span> (<\/span>nh-><\/span>nlmsg_type ==<\/span> NLMSG_DONE)<\/span> {<\/span>
          \n puts<\/span>(<\/span>"nh->nlmsg_type == NLMSG_DONE"<\/span>)<\/span>;<\/span>
          \n return<\/span>;<\/span>
          \n }<\/span>
          \n \/\/ \u6d88\u606f\u9519\u8bef\u6807\u8bc6<\/span>
          \n if<\/span> (<\/span>nh-><\/span>nlmsg_type ==<\/span> NLMSG_ERROR)<\/span> {<\/span>
          \n puts<\/span>(<\/span>"nh->nlmsg_type == NLMSG_ERROR"<\/span>)<\/span>;<\/span>
          \n return<\/span>;<\/span>
          \n }<\/span><\/p>\n

          #<\/span>if<\/span> 1<\/span><\/span><\/span>
          \n \/\/ \u6253\u5370\u4ece\u5185\u6838\u63a5\u6536\u7684\u6570\u636e<\/span>
          \n puts<\/span>(<\/span>"Data received from kernel:"<\/span>)<\/span>;<\/span>
          \n hex_dump<\/span>(<\/span>(<\/span>u8*<\/span>)<\/span>NLMSG_DATA<\/span>(<\/span>nh)<\/span>,<\/span> NLMSG_PAYLOAD<\/span>(<\/span>nh,<\/span> 0<\/span>)<\/span>)<\/span>;<\/span>
          \n#<\/span>endif<\/span><\/span>
          \n }<\/span>
          \n}<\/span><\/p>\n

          4.2.2 \u5185\u6838\u6a21\u5757\u5173\u952e\u4ee3\u7801<\/h6>\n

          \u5185\u6838\u6a21\u5757\u9700\u9632\u6b62\u8d44\u6e90\u62a2\u5360，\u786e\u4fdd Netlink \u8d44\u6e90\u7684\u4e92\u65a5\u8bbf\u95ee，\u5173\u952e\u4ee3\u7801\u5982\u4e0b：<\/p>\n

          static<\/span> void<\/span> nl_rcv<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>
          \n{<\/span>
          \n \/\/ \u52a0\u9501\u4fdd\u8bc1\u8d44\u6e90\u4e92\u65a5\u8bbf\u95ee<\/span>
          \n mutex_lock<\/span>(<\/span>&<\/span>nl_mtx)<\/span>;<\/span>
          \n netlink_rcv_skb<\/span>(<\/span>skb,<\/span> &<\/span>nl_rcv_msg)<\/span>;<\/span>
          \n mutex_unlock<\/span>(<\/span>&<\/span>nl_mtx)<\/span>;<\/span>
          \n}<\/span><\/p>\n

          static<\/span> int<\/span> nl_send_msg<\/span>(<\/span>const<\/span> u8 *<\/span>data,<\/span> int<\/span> data_len)<\/span>
          \n{<\/span>
          \n struct<\/span> nlmsghdr<\/span> *<\/span>rep;<\/span>
          \n u8 *<\/span>res;<\/span>
          \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span><\/p>\n

          \/\/ \u53c2\u6570\u5408\u6cd5\u6027\u6821\u9a8c<\/span>
          \n if<\/span>(<\/span>g_pid <<\/span> 0<\/span> ||<\/span> g_nl_sk ==<\/span> NULL<\/span>)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"Invalid parameter, g_pid = %d, g_nl_sk = %p\\\\n"<\/span>,<\/span> g_pid,<\/span> g_nl_sk)<\/span>;<\/span>
          \n return<\/span> –<\/span>1<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u5206\u914d\u65b0\u7684sk_buff\u7f13\u51b2\u533a<\/span>
          \n skb =<\/span> nlmsg_new<\/span>(<\/span>data_len,<\/span> GFP_KERNEL)<\/span>;<\/span>
          \n if<\/span>(<\/span>!<\/span>skb)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"nlmsg_new failed!!!\\\\n"<\/span>)<\/span>;<\/span>
          \n return<\/span> –<\/span>1<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u8c03\u8bd5\u6a21\u5f0f\u4e0b\u6253\u5370\u5f85\u53d1\u9001\u6570\u636e<\/span>
          \n if<\/span>(<\/span>g_debug_level ><\/span> 0<\/span>)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"Data to be send to user space:\\\\n"<\/span>)<\/span>;<\/span>
          \n hex_dump<\/span>(<\/span>(<\/span>void<\/span>*<\/span>)<\/span>data,<\/span> data_len)<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u586b\u5145Netlink\u6d88\u606f\u5934<\/span>
          \n rep =<\/span> __nlmsg_put<\/span>(<\/span>skb,<\/span> g_pid,<\/span> 0<\/span>,<\/span> NLMSG_NOOP,<\/span> data_len,<\/span> 0<\/span>)<\/span>;<\/span>
          \n res =<\/span> nlmsg_data<\/span>(<\/span>rep)<\/span>;<\/span>
          \n memcpy<\/span>(<\/span>res,<\/span> data,<\/span> data_len)<\/span>;<\/span><\/p>\n

          \/\/ \u53d1\u9001\u5355\u64ad\u6d88\u606f\u81f3\u7528\u6237\u7a7a\u95f4<\/span>
          \n netlink_unicast<\/span>(<\/span>g_nl_sk,<\/span> skb,<\/span> g_pid,<\/span> MSG_DONTWAIT)<\/span>;<\/span>
          \n return<\/span> 0<\/span>;<\/span>
          \n}<\/span><\/p>\n

          static<\/span> int<\/span> nl_rcv_msg<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> struct<\/span> nlmsghdr<\/span> *<\/span>nlh)<\/span>
          \n{<\/span>
          \n const<\/span> u8 res_data[<\/span>]<\/span> =<\/span> "Hello, user"<\/span>;<\/span>
          \n size_t<\/span> data_len;<\/span>
          \n u8 *<\/span>buf;<\/span>
          \n struct<\/span> user_data_<\/span> *<\/span>pck;<\/span>
          \n struct<\/span> user_req<\/span> *<\/span>req,<\/span> *<\/span>match =<\/span> NULL<\/span>;<\/span><\/p>\n

          \/\/ \u83b7\u53d6\u53d1\u9001\u65b9\u8fdb\u7a0bID<\/span>
          \n g_pid =<\/span> NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>pid;<\/span>
          \n buf =<\/span> (<\/span>u8*<\/span>)<\/span>NLMSG_DATA<\/span>(<\/span>nlh)<\/span>;<\/span>
          \n data_len =<\/span> nlmsg_len<\/span>(<\/span>nlh)<\/span>;<\/span><\/p>\n

          \/\/ \u6570\u636e\u957f\u5ea6\u6821\u9a8c<\/span>
          \n if<\/span>(<\/span>data_len <<\/span> sizeof<\/span>(<\/span>struct<\/span> user_data_<\/span>)<\/span>)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"Too short data from user space!!!\\\\n"<\/span>)<\/span>;<\/span>
          \n return<\/span> –<\/span>1<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u89e3\u6790\u7528\u6237\u7a7a\u95f4\u6d88\u606f<\/span>
          \n pck =<\/span> (<\/span>struct<\/span> user_data_<\/span> *<\/span>)<\/span>buf;<\/span>
          \n if<\/span>(<\/span>pck-><\/span>magic_num !=<\/span> MAGIC_NUM_RNQ)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"Magic number not matched!!!\\\\n"<\/span>)<\/span>;<\/span>
          \n return<\/span> –<\/span>1<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u8c03\u8bd5\u6a21\u5f0f\u4e0b\u6253\u5370\u7528\u6237\u7a7a\u95f4\u6570\u636e<\/span>
          \n if<\/span>(<\/span>g_debug_level ><\/span> 0<\/span>)<\/span> {<\/span>
          \n printk<\/span>(<\/span>"Data from user space:\\\\n"<\/span>)<\/span>;<\/span>
          \n hex_dump<\/span>(<\/span>buf,<\/span> data_len)<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u5339\u914d\u5bf9\u5e94\u7684\u8bf7\u6c42\u5904\u7406\u51fd\u6570<\/span>
          \n req =<\/span> user_reqs;<\/span>
          \n while<\/span>(<\/span>req-><\/span>op)<\/span> {<\/span>
          \n if<\/span>(<\/span>req-><\/span>op ==<\/span> pck-><\/span>op)<\/span> {<\/span>
          \n match =<\/span> req;<\/span>
          \n break<\/span>;<\/span>
          \n }<\/span>
          \n req++<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u6267\u884c\u5339\u914d\u7684\u5904\u7406\u51fd\u6570<\/span>
          \n if<\/span>(<\/span>match)<\/span> {<\/span>
          \n match-><\/span>handler<\/span>(<\/span>buf,<\/span> data_len)<\/span>;<\/span>
          \n }<\/span><\/p>\n

          \/\/ \u5411\u7528\u6237\u7a7a\u95f4\u56de\u590d\u6d88\u606f<\/span>
          \n nl_send_msg<\/span>(<\/span>res_data,<\/span> sizeof<\/span>(<\/span>res_data)<\/span>)<\/span>;<\/span>
          \n return<\/span> 0<\/span>;<\/span>
          \n}<\/span><\/p>\n

          5 \u5176\u4ed6\u76f8\u5173\u8bf4\u660e<\/h4>\n

          Netlink \u662f Linux \u7279\u6709\u7684\u4e00\u79cd\u4e13\u7528 Socket，\u529f\u80fd\u7c7b\u4f3c\u4e8e BSD \u7cfb\u7edf\u4e2d\u7684 AF_ROUTE，\u4f46\u5177\u5907\u66f4\u4e30\u5bcc\u7684\u529f\u80fd\u3002\u5728 Linux 2.6.14 \u5185\u6838\u7248\u672c\u4e2d，\u5927\u91cf\u5e94\u7528\u901a\u8fc7 Netlink \u5b9e\u73b0\u5e94\u7528\u5c42\u4e0e\u5185\u6838\u5c42\u7684\u901a\u4fe1，\u5178\u578b\u573a\u666f\u5305\u62ec：<\/p>\n

            \n
          • \u8def\u7531\u5b88\u62a4\u8fdb\u7a0b（NETLINK_ROUTE）；<\/li>\n
          • 1-wire \u5b50\u7cfb\u7edf（NETLINK_W1）；<\/li>\n
          • \u7528\u6237\u6001 Socket \u534f\u8bae（NETLINK_USERSOCK）；<\/li>\n
          • \u9632\u706b\u5899（NETLINK_FIREWALL）；<\/li>\n
          • Socket \u76d1\u63a7（NETLINK_INET_DIAG）；<\/li>\n
          • netfilter \u65e5\u5fd7（NETLINK_NFLOG）；<\/li>\n
          • IPsec \u5b89\u5168\u7b56\u7565（NETLINK_XFRM）；<\/li>\n
          • SELinux \u4e8b\u4ef6\u901a\u77e5（NETLINK_SELINUX）；<\/li>\n
          • iSCSI \u5b50\u7cfb\u7edf（NETLINK_ISCSI）；<\/li>\n
          • \u8fdb\u7a0b\u5ba1\u8ba1（NETLINK_AUDIT）；<\/li>\n
          • \u8f6c\u53d1\u4fe1\u606f\u8868\u67e5\u8be2（NETLINK_FIB_LOOKUP）；<\/li>\n
          • Netlink \u8fde\u63a5\u5668（NETLINK_CONNECTOR）；<\/li>\n
          • netfilter \u5b50\u7cfb\u7edf（NETLINK_NETFILTER）；<\/li>\n
          • IPv6 \u9632\u706b\u5899（NETLINK_IP6_FW）；<\/li>\n
          • DECnet \u8def\u7531\u4fe1\u606f（NETLINK_DNRTMSG）；<\/li>\n
          • \u5185\u6838\u4e8b\u4ef6\u5411\u7528\u6237\u6001\u901a\u77e5（NETLINK_KOBJECT_UEVENT）；<\/li>\n
          • \u901a\u7528 Netlink（NETLINK_GENERIC）\u3002<\/li>\n<\/ul>\n

            Netlink \u662f\u5b9e\u73b0\u5185\u6838\u4e0e\u7528\u6237\u5e94\u7528\u95f4\u53cc\u5411\u6570\u636e\u4f20\u8f93\u7684\u9ad8\u6548\u65b9\u5f0f：\u7528\u6237\u6001\u5e94\u7528\u53ef\u901a\u8fc7\u6807\u51c6 Socket API \u8c03\u7528 Netlink \u7684\u529f\u80fd，\u5185\u6838\u6001\u5219\u9700\u901a\u8fc7\u4e13\u7528\u5185\u6838 API \u5b9e\u73b0 Netlink \u901a\u4fe1\u3002<\/p>\n

            \u76f8\u8f83\u4e8e\u7cfb\u7edf\u8c03\u7528\u3001ioctl \u53ca \/proc \u6587\u4ef6\u7cfb\u7edf，Netlink \u5177\u5907\u4ee5\u4e0b\u4f18\u52bf：<\/p>\n

          • \u4f7f\u7528 Netlink \u65f6，\u4ec5\u9700\u5728 include\/linux\/netlink.h \u4e2d\u65b0\u589e Netlink \u534f\u8bae\u5b9a\u4e49（\u5982 #define NETLINK_MYTEST 17），\u5185\u6838\u4e0e\u7528\u6237\u6001\u5e94\u7528\u5373\u53ef\u901a\u8fc7 Socket API \u57fa\u4e8e\u8be5\u534f\u8bae\u5b8c\u6210\u6570\u636e\u4ea4\u6362；\u800c\u65b0\u589e\u7cfb\u7edf\u8c03\u7528\u9700\u4fee\u6539\u5185\u6838\u6e90\u7801\u5e76\u9759\u6001\u7f16\u8bd1，ioctl \u9700\u65b0\u589e\u8bbe\u5907\/\u6587\u4ef6，\/proc \u6587\u4ef6\u7cfb\u7edf\u9700\u65b0\u589e\u6587\u4ef6\/\u76ee\u5f55，\u5747\u4f1a\u589e\u52a0\u5f00\u53d1\u6210\u672c\u6216\u5bfc\u81f4 \/proc \u76ee\u5f55\u7ed3\u6784\u6df7\u4e71；<\/li>\n
          • Netlink \u4e3a\u5f02\u6b65\u901a\u4fe1\u673a\u5236，\u5185\u6838\u4e0e\u7528\u6237\u6001\u5e94\u7528\u95f4\u7684\u6d88\u606f\u5b58\u50a8\u4e8e Socket \u7f13\u5b58\u961f\u5217，\u53d1\u9001\u6d88\u606f\u4ec5\u9700\u5c06\u5176\u5b58\u5165\u63a5\u6536\u8005\u7684 Socket \u63a5\u6536\u961f\u5217，\u65e0\u9700\u7b49\u5f85\u63a5\u6536\u65b9\u786e\u8ba4；\u800c\u7cfb\u7edf\u8c03\u7528\u4e0e ioctl \u4e3a\u540c\u6b65\u901a\u4fe1\u673a\u5236，\u4f20\u8f93\u5927\u5c3a\u5bf8\u6570\u636e\u65f6\u4f1a\u5f71\u54cd\u7cfb\u7edf\u8c03\u5ea6\u7c92\u5ea6；<\/li>\n
          • \u57fa\u4e8e Netlink \u7684\u5185\u6838\u6a21\u5757\u53ef\u52a8\u6001\u52a0\u8f7d，\u5e94\u7528\u5c42\u4e0e\u5185\u6838\u5c42\u65e0\u7f16\u8bd1\u671f\u4f9d\u8d56；\u800c\u65b0\u589e\u7cfb\u7edf\u8c03\u7528\u9700\u9759\u6001\u94fe\u63a5\u81f3\u5185\u6838，\u65e0\u6cd5\u901a\u8fc7\u6a21\u5757\u5b9e\u73b0，\u4e14\u5e94\u7528\u5c42\u7f16\u8bd1\u65f6\u9700\u4f9d\u8d56\u5185\u6838\u5934\u6587\u4ef6；<\/li>\n
          • Netlink \u652f\u6301\u591a\u64ad\u7279\u6027，\u5185\u6838\u6a21\u5757\u6216\u5e94\u7528\u53ef\u5c06\u6d88\u606f\u591a\u64ad\u81f3\u6307\u5b9a Netlink \u7ec4，\u5f52\u5c5e\u8be5\u7ec4\u7684\u6240\u6709\u5185\u6838\u6a21\u5757\/\u5e94\u7528\u5747\u53ef\u63a5\u6536\u6d88\u606f（\u5185\u6838\u4e8b\u4ef6\u5411\u7528\u6237\u6001\u901a\u77e5\u673a\u5236\u5373\u57fa\u4e8e\u6b64\u7279\u6027）；<\/li>\n
          • \u5185\u6838\u53ef\u4e3b\u52a8\u53d1\u8d77 Netlink \u4f1a\u8bdd，\u800c\u7cfb\u7edf\u8c03\u7528\u4e0e ioctl \u4ec5\u80fd\u7531\u7528\u6237\u5e94\u7528\u53d1\u8d77；<\/li>\n
          • Netlink \u57fa\u4e8e\u6807\u51c6 Socket API \u5b9e\u73b0，\u5f00\u53d1\u95e8\u69db\u4f4e；\u800c\u7cfb\u7edf\u8c03\u7528\u4e0e ioctl \u9700\u638c\u63e1\u4e13\u7528\u5f00\u53d1\u89c4\u8303，\u5b66\u4e60\u6210\u672c\u66f4\u9ad8\u3002<\/li>\n

            \u7528\u6237\u6001\u4f7f\u7528 Netlink<\/h4>\n

            \u7528\u6237\u6001\u5e94\u7528\u53ef\u901a\u8fc7\u6807\u51c6 Socket API（socket()\u3001bind()\u3001sendmsg()\u3001recvmsg()\u3001close()）\u4fbf\u6377\u4f7f\u7528 Netlink Socket，\u9700\u5305\u542b\u5934\u6587\u4ef6 linux\/netlink.h \u4e0e sys\/socket.h（Socket \u57fa\u7840\u5934\u6587\u4ef6）\u3002<\/p>\n

            5.1 \u521b\u5efa Netlink Socket<\/h5>\n

            \u8c03\u7528 socket() \u51fd\u6570\u521b\u5efa Netlink Socket，\u539f\u578b\u5982\u4e0b： KaTeX parse error: Expected 'EOF', got '_' at position 16: \\\\text{socket(AF_\u0332NETLINK, SOCK_R\u2026<\/span> \u53c2\u6570\u8bf4\u660e：<\/p>\n

              \n
            • \u7b2c\u4e00\u4e2a\u53c2\u6570：\u5fc5\u987b\u4e3a AF_NETLINK \u6216 PF_NETLINK（Linux \u4e2d\u4e8c\u8005\u7b49\u4ef7），\u6807\u8bc6\u4f7f\u7528 Netlink \u534f\u8bae\u65cf；<\/li>\n
            • \u7b2c\u4e8c\u4e2a\u53c2\u6570：\u5fc5\u987b\u4e3a SOCK_RAW \u6216 SOCK_DGRAM；<\/li>\n
            • \u7b2c\u4e09\u4e2a\u53c2\u6570：\u6307\u5b9a Netlink \u534f\u8bae\u7c7b\u578b（\u5982\u81ea\u5b9a\u4e49\u7684 NETLINK_MYTEST，\u6216\u901a\u7528\u534f\u8bae NETLINK_GENERIC）\u3002<\/li>\n<\/ul>\n

              \u5185\u6838\u9884\u5b9a\u4e49\u7684 Netlink \u534f\u8bae\u7c7b\u578b\u5982\u4e0b：<\/p>\n

              #<\/span>define<\/span> NETLINK_ROUTE<\/span> 0<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_W1<\/span> 1<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_USERSOCK<\/span> 2<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_FIREWALL<\/span> 3<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_INET_DIAG<\/span> 4<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_NFLOG<\/span> 5<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_XFRM<\/span> 6<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_SELINUX<\/span> 7<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_ISCSI<\/span> 8<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_AUDIT<\/span> 9<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_FIB_LOOKUP<\/span> 10<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_CONNECTOR<\/span> 11<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_NETFILTER<\/span> 12<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_IP6_FW<\/span> 13<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_DNRTMSG<\/span> 14<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_KOBJECT_UEVENT<\/span> 15<\/span><\/span><\/span>
              \n#<\/span>define<\/span> NETLINK_GENERIC<\/span> 16<\/span><\/span><\/span><\/p>\n

              \u6bcf\u4e2a Netlink \u534f\u8bae\u7c7b\u578b\u6700\u591a\u652f\u6301 32 \u4e2a\u591a\u64ad\u7ec4，\u6bcf\u4e2a\u591a\u64ad\u7ec4\u7531 1 \u4e2a\u6bd4\u7279\u4f4d\u6807\u8bc6\u3002Netlink \u7684\u591a\u64ad\u7279\u6027\u53ef\u663e\u8457\u964d\u4f4e\u591a\u64ad\u573a\u666f\u4e0b\u7684\u7cfb\u7edf\u8c03\u7528\u6b21\u6570\u3002<\/p>\n

              5.2 \u7ed1\u5b9a Netlink Socket<\/h5>\n

              bind() \u51fd\u6570\u7528\u4e8e\u5c06\u5df2\u6253\u5f00\u7684 Netlink Socket \u4e0e\u672c\u5730 Netlink \u5730\u5740\u7ed1\u5b9a，Netlink Socket \u5730\u5740\u7ed3\u6784\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

              struct<\/span> sockaddr_nl<\/span> {<\/span>
              \n sa_family_t<\/span> nl_family;<\/span>
              \n unsigned<\/span> short<\/span> nl_pad;<\/span>
              \n __u32 nl_pid;<\/span>
              \n __u32 nl_groups;<\/span>
              \n}<\/span>;<\/span><\/p>\n

              \u5b57\u6bb5\u8bf4\u660e：<\/p>\n

                \n
              • nl_family：\u5fc5\u987b\u8bbe\u7f6e\u4e3a AF_NETLINK \u6216 PF_NETLINK；<\/li>\n
              • nl_pad：\u9884\u7559\u5b57\u6bb5，\u9700\u8bbe\u7f6e\u4e3a 0；<\/li>\n
              • nl_pid：\u63a5\u6536\/\u53d1\u9001\u6d88\u606f\u7684\u8fdb\u7a0b ID（\u5185\u6838\u5904\u7406\/\u591a\u64ad\u6d88\u606f\u65f6\u8bbe\u4e3a 0，\u5426\u5219\u8bbe\u4e3a\u8fdb\u7a0b ID；\u591a\u7ebf\u7a0b\u573a\u666f\u4e0b\u53ef\u81ea\u5b9a\u4e49，\u5982 pthread_self() << 16 | getpid()）；<\/li>\n
              • nl_groups：\u591a\u64ad\u7ec4\u6807\u8bc6（\u8bbe\u4e3a 0 \u8868\u793a\u4e0d\u52a0\u5165\u4efb\u4f55\u591a\u64ad\u7ec4）\u3002<\/li>\n<\/ul>\n

                bind() \u51fd\u6570\u8c03\u7528\u793a\u4f8b：<\/p>\n

                bind<\/span>(<\/span>fd,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>nladdr,<\/span> sizeof<\/span>(<\/span>struct<\/span> sockaddr_nl<\/span>)<\/span>)<\/span>;<\/span><\/p>\n

                \u5176\u4e2d，fd \u4e3a socket() \u51fd\u6570\u8fd4\u56de\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26，nladdr \u4e3a struct sockaddr_nl \u7c7b\u578b\u7684\u5730\u5740\u7ed3\u6784\u4f53\u3002<\/p>\n

                5.3 \u53d1\u9001 Netlink \u6d88\u606f<\/h5>\n

                \u5411\u5185\u6838\/\u5176\u4ed6\u7528\u6237\u6001\u5e94\u7528\u53d1\u9001 Netlink \u6d88\u606f\u65f6，\u9700\u6784\u9020\u76ee\u6807 Netlink \u5730\u5740\u3001struct msghdr\u3001struct nlmsghdr \u4e0e struct iovec \u7ed3\u6784\u4f53：<\/p>\n

                5.3.1 \u6d88\u606f\u5934\u4e0e\u5730\u5740\u914d\u7f6e<\/h6>\n

                struct<\/span> msghdr<\/span> msg;<\/span>
                \nmemset<\/span>(<\/span>&<\/span>msg,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>msg)<\/span>)<\/span>;<\/span>
                \nmsg.<\/span>msg_name =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>&<\/span>(<\/span>nladdr)<\/span>;<\/span> \/\/ \u76ee\u6807Netlink\u5730\u5740<\/span>
                \nmsg.<\/span>msg_namelen =<\/span> sizeof<\/span>(<\/span>nladdr)<\/span>;<\/span><\/p>\n

                5.3.2 Netlink \u6d88\u606f\u5934\u914d\u7f6e<\/h6>\n

                struct nlmsghdr \u4e3a Netlink \u6d88\u606f\u5934（\u63a7\u5236\u5757），\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

                struct<\/span> nlmsghdr<\/span> {<\/span>
                \n __u32 nlmsg_len;<\/span> \/\/ \u6d88\u606f\u603b\u957f\u5ea6（\u542b\u6d88\u606f\u5934+\u8f7d\u8377）<\/span>
                \n __u16 nlmsg_type;<\/span> \/\/ \u5e94\u7528\u81ea\u5b9a\u4e49\u6d88\u606f\u7c7b\u578b（\u5185\u6838\u900f\u4f20，\u901a\u5e38\u8bbe\u4e3a0）<\/span>
                \n __u16 nlmsg_flags;<\/span> \/\/ \u6d88\u606f\u6807\u5fd7（\u666e\u901a\u573a\u666f\u8bbe\u4e3a0）<\/span>
                \n __u32 nlmsg_seq;<\/span> \/\/ \u6d88\u606f\u5e8f\u5217\u53f7（\u5e94\u7528\u8ffd\u8e2a\u6d88\u606f\u7528）<\/span>
                \n __u32 nlmsg_pid;<\/span> \/\/ \u6d88\u606f\u53d1\u9001\u8fdb\u7a0bID<\/span>
                \n}<\/span>;<\/span><\/p>\n

                \u6d88\u606f\u6807\u5fd7（nlmsg_flags）\u53ef\u9009\u503c：<\/p>\n

                #<\/span>define<\/span> NLM_F_REQUEST<\/span> 1<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_MULTI<\/span> 2<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_ACK<\/span> 4<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_ECHO<\/span> 8<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_ROOT<\/span> 0x100<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_MATCH<\/span> 0x200<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_ATOMIC<\/span> 0x400<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_DUMP<\/span> (<\/span>NLM_F_ROOT|<\/span>NLM_F_MATCH)<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_REPLACE<\/span> 0x100<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_EXCL<\/span> 0x200<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_CREATE<\/span> 0x400<\/span><\/span><\/span>
                \n#<\/span>define<\/span> NLM_F_APPEND<\/span> 0x800<\/span><\/span><\/span><\/p>\n

                5.3.3 \u6d88\u606f\u8f7d\u8377\u4e0e\u53d1\u9001\u793a\u4f8b<\/h6>\n

                #<\/span>define<\/span> MAX_MSGSIZE<\/span> 1024<\/span><\/span><\/span>
                \nchar<\/span> buffer[<\/span>]<\/span> =<\/span> "An example message"<\/span>;<\/span>
                \nstruct<\/span> nlmsghdr<\/span> *<\/span>nlhdr;<\/span><\/p>\n

                \/\/ \u5206\u914d\u6d88\u606f\u7f13\u51b2\u533a<\/span>
                \nnlhdr =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_MSGSIZE)<\/span>)<\/span>;<\/span>
                \n\/\/ \u586b\u5145\u6d88\u606f\u8f7d\u8377<\/span>
                \nstrcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>nlhdr)<\/span>,<\/span>buffer)<\/span>;<\/span>
                \n\/\/ \u8bbe\u7f6e\u6d88\u606f\u957f\u5ea6<\/span>
                \nnlhdr-><\/span>nlmsg_len =<\/span> NLMSG_LENGTH<\/span>(<\/span>strlen<\/span>(<\/span>buffer)<\/span>)<\/span>;<\/span>
                \n\/\/ \u8bbe\u7f6e\u53d1\u9001\u8fdb\u7a0bID<\/span>
                \nnlhdr-><\/span>nlmsg_pid =<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span>
                \n\/\/ \u6d88\u606f\u6807\u5fd7\u8bbe\u4e3a0<\/span>
                \nnlhdr-><\/span>nlmsg_flags =<\/span> 0<\/span>;<\/span><\/p>\n

                \/\/ \u6784\u9020iovec\u7ed3\u6784\u4f53<\/span>
                \nstruct<\/span> iovec<\/span> iov;<\/span>
                \niov.<\/span>iov_base =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>nlhdr;<\/span>
                \niov.<\/span>iov_len =<\/span> nlhdr-><\/span>nlmsg_len;<\/span>
                \nmsg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
                \nmsg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

                \/\/ \u53d1\u9001\u6d88\u606f<\/span>
                \nsendmsg<\/span>(<\/span>fd,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

                5.4 \u63a5\u6536 Netlink \u6d88\u606f<\/h5>\n

                \u63a5\u6536\u6d88\u606f\u9700\u5148\u5206\u914d\u8db3\u591f\u5927\u7684\u7f13\u51b2\u533a，\u518d\u8c03\u7528 recvmsg() \u51fd\u6570，\u793a\u4f8b\u5982\u4e0b：<\/p>\n

                #<\/span>define<\/span> MAX_NL_MSG_LEN<\/span> 1024<\/span><\/span><\/span>
                \nstruct<\/span> sockaddr_nl<\/span> nladdr;<\/span>
                \nstruct<\/span> msghdr<\/span> msg;<\/span>
                \nstruct<\/span> iovec<\/span> iov;<\/span>
                \nstruct<\/span> nlmsghdr<\/span> *<\/span> nlhdr;<\/span><\/p>\n

                \/\/ \u5206\u914d\u7f13\u51b2\u533a<\/span>
                \nnlhdr =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>MAX_NL_MSG_LEN)<\/span>;<\/span>
                \niov.<\/span>iov_base =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>nlhdr;<\/span>
                \niov.<\/span>iov_len =<\/span> MAX_NL_MSG_LEN;<\/span><\/p>\n

                \/\/ \u521d\u59cb\u5316\u6d88\u606f\u5934<\/span>
                \nmsg.<\/span>msg_name =<\/span> (<\/span>void<\/span> *<\/span>)<\/span>&<\/span>(<\/span>nladdr)<\/span>;<\/span>
                \nmsg.<\/span>msg_namelen =<\/span> sizeof<\/span>(<\/span>nladdr)<\/span>;<\/span>
                \nmsg.<\/span>msg_iov =<\/span> &<\/span>iov;<\/span>
                \nmsg.<\/span>msg_iovlen =<\/span> 1<\/span>;<\/span><\/p>\n

                \/\/ \u63a5\u6536\u6d88\u606f<\/span>
                \nrecvmsg<\/span>(<\/span>fd,<\/span> &<\/span>msg,<\/span> 0<\/span>)<\/span>;<\/span><\/p>\n

                \u63a5\u6536\u5b8c\u6210\u540e：<\/p>\n

                  \n
                • nlhdr \u6307\u5411\u6d88\u606f\u5934；<\/li>\n
                • nladdr \u5b58\u50a8\u6d88\u606f\u7684\u76ee\u6807\u5730\u5740；<\/li>\n
                • NLMSG_DATA(nlhdr) \u5b8f\u8fd4\u56de\u6d88\u606f\u8f7d\u8377\u7684\u9996\u5730\u5740\u3002<\/li>\n<\/ul>\n
                  5.5 Netlink \u6d88\u606f\u5904\u7406\u5b8f<\/h5>\n

                  linux\/netlink.h \u5b9a\u4e49\u4e86\u4ee5\u4e0b\u5e38\u7528\u5b8f，\u7528\u4e8e\u7b80\u5316\u6d88\u606f\u5904\u7406：<\/p>\n

                • \n

                  \u5b57\u8282\u5bf9\u9f50\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_ALIGNTO \\\\ 4<\/span><\/span><\/span>
                  \n#<\/span>define<\/span> \\\\ NLMSG\\\\_ALIGN<\/span>(<\/span>len)<\/span> \\\\ (<\/span> (<\/span>(<\/span>len)<\/span>+<\/span>NLMSG\\\\_ALIGNTO–<\/span>1<\/span>)<\/span> \\\\&<\/span> \\\\sim<\/span>(<\/span>NLMSG\\\\_ALIGNTO–<\/span>1<\/span>)<\/span> )<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u83b7\u53d6\u4e0d\u5c0f\u4e8e len \u4e14\u6ee1\u8db3\u5b57\u8282\u5bf9\u9f50\u7684\u6700\u5c0f\u6570\u503c\u3002<\/p>\n<\/li>\n

                • \n

                  \u6d88\u606f\u957f\u5ea6\u8ba1\u7b97\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_LENGTH<\/span>(<\/span>len)<\/span> \\\\ (<\/span>(<\/span>len)<\/span>+<\/span>NLMSG\\\\_ALIGN<\/span>(<\/span>sizeof<\/span>(<\/span>struct<\/span> \\\\ nlmsghdr)<\/span>)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u8ba1\u7b97\u8f7d\u8377\u957f\u5ea6\u4e3a len \u65f6\u7684\u6d88\u606f\u603b\u957f\u5ea6（\u7528\u4e8e\u5206\u914d\u7f13\u51b2\u533a）\u3002<\/p>\n<\/li>\n

                • \n

                  \u7f13\u51b2\u533a\u7a7a\u95f4\u8ba1\u7b97\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_SPACE<\/span>(<\/span>len)<\/span> \\\\ NLMSG\\\\_ALIGN<\/span>(<\/span>NLMSG\\\\_LENGTH<\/span>(<\/span>len)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u8fd4\u56de\u4e0d\u5c0f\u4e8e NLMSG_LENGTH(len) \u4e14\u5b57\u8282\u5bf9\u9f50\u7684\u6700\u5c0f\u6570\u503c（\u7528\u4e8e\u7f13\u51b2\u533a\u5206\u914d）\u3002<\/p>\n<\/li>\n

                • \n

                  \u8f7d\u8377\u5730\u5740\u83b7\u53d6\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_DATA<\/span>(<\/span>nlh)<\/span> \\\\ (<\/span>(<\/span>void<\/span>*<\/span>)<\/span>(<\/span>(<\/span>(<\/span>char<\/span>*<\/span>)<\/span>nlh)<\/span> +<\/span> NLMSG\\\\_LENGTH<\/span>(<\/span>0<\/span>)<\/span>)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u8fd4\u56de\u6d88\u606f\u8f7d\u8377\u7684\u9996\u5730\u5740\u3002<\/p>\n<\/li>\n

                • \n

                  \u4e0b\u4e00\u6761\u6d88\u606f\u83b7\u53d6\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_NEXT<\/span>(<\/span>nlh,<\/span>len)<\/span> \\\\ (<\/span>(<\/span>len)<\/span> -=<\/span> NLMSG\\\\_ALIGN<\/span>(<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg\\\\_len)<\/span>,<\/span> \\\\\\\\ (<\/span>struct<\/span> \\\\ nlmsghdr*<\/span>)<\/span>(<\/span>(<\/span>(<\/span>char<\/span>*<\/span>)<\/span>(<\/span>nlh)<\/span>)<\/span> +<\/span> NLMSG\\\\_ALIGN<\/span>(<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg\\\\_len)<\/span>)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u83b7\u53d6\u4e0b\u4e00\u6761\u6d88\u606f\u7684\u9996\u5730\u5740，\u5e76\u66f4\u65b0\u5269\u4f59\u6d88\u606f\u957f\u5ea6\u3002<\/p>\n<\/li>\n

                • \n

                  \u6d88\u606f\u5408\u6cd5\u6027\u6821\u9a8c\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_OK<\/span>(<\/span>nlh,<\/span>len)<\/span> \\\\ (<\/span>(<\/span>len)<\/span> >=<\/span> (<\/span>int<\/span>)<\/span>sizeof<\/span>(<\/span>struct<\/span> \\\\ nlmsghdr)<\/span> \\\\&<\/span>\\\\&<\/span> \\\\\\\\ (<\/span>nlh)<\/span>-><\/span>nlmsg\\\\_len >=<\/span> sizeof<\/span>(<\/span>struct<\/span> \\\\ nlmsghdr)<\/span> \\\\&<\/span>\\\\&<\/span> \\\\\\\\ (<\/span>nlh)<\/span>-><\/span>nlmsg\\\\_len <=<\/span> (<\/span>len)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u6821\u9a8c\u6d88\u606f\u957f\u5ea6\u662f\u5426\u5408\u6cd5\u3002<\/p>\n<\/li>\n

                • \n

                  \u8f7d\u8377\u957f\u5ea6\u8ba1\u7b97\u5b8f：<\/p>\n

                  #<\/span>define<\/span> \\\\ NLMSG\\\\_PAYLOAD<\/span>(<\/span>nlh,<\/span>len)<\/span> \\\\ (<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg\\\\_len –<\/span> NLMSG\\\\_SPACE<\/span>(<\/span>(<\/span>len)<\/span>)<\/span>)<\/span><\/span><\/span><\/p>\n

                  \u529f\u80fd：\u8fd4\u56de\u6d88\u606f\u8f7d\u8377\u7684\u5b9e\u9645\u957f\u5ea6\u3002<\/p>\n<\/li>\n

                  5.6 \u5173\u95ed Netlink Socket<\/h5>\n

                  \u8c03\u7528 close(fd) \u51fd\u6570\u5173\u95ed\u5df2\u6253\u5f00\u7684 Netlink Socket \u6587\u4ef6\u63cf\u8ff0\u7b26\u5373\u53ef\u3002<\/p>\n

                  Netlink \u5185\u6838 API<\/h4>\n

                  Netlink \u7684\u5185\u6838\u5b9e\u73b0\u5728 net\/core\/af_netlink.c \u6587\u4ef6\u4e2d，\u5185\u6838\u6a21\u5757\u4f7f\u7528 Netlink \u9700\u5305\u542b linux\/netlink.h \u5934\u6587\u4ef6，\u5e76\u8c03\u7528\u4e13\u7528\u5185\u6838 API\u3002<\/p>\n

                  6.1 \u65b0\u589e Netlink \u534f\u8bae\u7c7b\u578b<\/h5>\n

                  \u5982\u9700\u65b0\u589e\u81ea\u5b9a\u4e49 Netlink \u534f\u8bae\u7c7b\u578b，\u9700\u4fee\u6539 linux\/netlink.h，\u793a\u4f8b\u5982\u4e0b：<\/p>\n

                  #<\/span>define<\/span> \\\\ NETLINK\\\\_MYTEST \\\\ 17<\/span><\/span><\/span><\/p>\n

                  \u4e5f\u53ef\u76f4\u63a5\u4f7f\u7528\u901a\u7528\u534f\u8bae\u7c7b\u578b NETLINK_GENERIC，\u65e0\u9700\u65b0\u589e\u5b9a\u4e49\u3002<\/p>\n

                  6.2 \u521b\u5efa\u5185\u6838 Netlink Socket<\/h5>\n

                  \u8c03\u7528 netlink_kernel_create() \u51fd\u6570\u521b\u5efa\u5185\u6838\u6001 Netlink Socket，\u539f\u578b\u5982\u4e0b： KaTeX parse error: Expected 'EOF', got '_' at position 28: \u2026 sock * netlink_\u0332kernel_create(i\u2026<\/span> \u53c2\u6570\u8bf4\u660e：<\/p>\n

                    \n
                  • unit：Netlink \u534f\u8bae\u7c7b\u578b（\u5982 NETLINK_MYTEST）；<\/li>\n
                  • input：\u6d88\u606f\u5904\u7406\u56de\u8c03\u51fd\u6570（Socket \u63a5\u6536\u6d88\u606f\u65f6\u89e6\u53d1）\u3002<\/li>\n<\/ul>\n
                    6.3 \u6d88\u606f\u5904\u7406\u56de\u8c03\u51fd\u6570<\/h5>\n

                    \u56de\u8c03\u51fd\u6570\u6709\u4e24\u79cd\u5b9e\u73b0\u65b9\u5f0f：<\/p>\n

                    6.3.1 \u76f4\u63a5\u5904\u7406\u6d88\u606f（\u9002\u7528\u4e8e\u77ed\u6d88\u606f）<\/h6>\n

                    void<\/span> input<\/span> (<\/span>struct<\/span> sock<\/span> *<\/span>sk,<\/span> int<\/span> len)<\/span> {<\/span>
                    \n struct<\/span> sk_buff<\/span> *<\/span>skb;<\/span>
                    \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
                    \n u8 *<\/span>data =<\/span> NULL<\/span>;<\/span>
                    \n while<\/span> (<\/span>(<\/span>skb =<\/span> skb_dequeue<\/span>(<\/span>&<\/span>sk-><\/span>receive_queue)<\/span>)<\/span> !=<\/span> NULL<\/span>)<\/span> {<\/span>
                    \n nlh =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>skb-><\/span>data;<\/span>
                    \n data =<\/span> NLMSG_DATA<\/span>(<\/span>nlh)<\/span>;<\/span>
                    \n \/\/ \u5904\u7406\u6d88\u606f\u8f7d\u8377<\/span>
                    \n }<\/span>
                    \n}<\/span><\/p>\n

                    6.3.2 \u5524\u9192\u5185\u6838\u7ebf\u7a0b\u5904\u7406（\u9002\u7528\u4e8e\u957f\u6d88\u606f）<\/h6>\n

                    void<\/span> input<\/span> (<\/span>struct<\/span> sock<\/span> *<\/span>sk,<\/span> int<\/span> len)<\/span> {<\/span>
                    \n \/\/ \u5524\u9192\u7b49\u5f85\u961f\u5217\u4e2d\u7684\u5185\u6838\u7ebf\u7a0b<\/span>
                    \n wake_up_interruptible<\/span>(<\/span>sk-><\/span>sk_sleep)<\/span>;<\/span>
                    \n}<\/span><\/p>\n

                    \u5185\u6838\u7ebf\u7a0b\u53ef\u901a\u8fc7 skb_recv_datagram(nl_sk) \u63a5\u6536\u6d88\u606f（\u65e0\u6d88\u606f\u65f6\u8fdb\u5165\u7761\u7720\u72b6\u6001）\u3002<\/p>\n

                    6.4 \u5185\u6838\u6001\u53d1\u9001\u6d88\u606f<\/h5>\n
                    6.4.1 \u5730\u5740\u914d\u7f6e<\/h6>\n

                    \u901a\u8fc7 NETLINK_CB(skb) \u5b8f\u914d\u7f6e\u6d88\u606f\u5730\u5740（\u6e90\/\u76ee\u6807）：<\/p>\n

                    NETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>pid =<\/span> 0<\/span>;<\/span> \/\/ \u6e90\u5730\u5740（\u5185\u6838\u8bbe\u4e3a0）<\/span>
                    \nNETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>dst_pid =<\/span> 0<\/span>;<\/span> \/\/ \u76ee\u6807\u8fdb\u7a0bID（\u5185\u6838\/\u591a\u64ad\u8bbe\u4e3a0）<\/span>
                    \nNETLINK_CB<\/span>(<\/span>skb)<\/span>.<\/span>dst_group =<\/span> 1<\/span>;<\/span> \/\/ \u76ee\u6807\u591a\u64ad\u7ec4（\u5355\u64ad\u8bbe\u4e3a0）<\/span><\/p>\n

                    6.4.2 \u53d1\u9001\u5355\u64ad\u6d88\u606f<\/h6>\n

                    \u8c03\u7528 netlink_unicast() \u51fd\u6570（\u539f\u578b\u89c1 3.2 \u8282）\u3002<\/p>\n

                    6.4.3 \u53d1\u9001\u5e7f\u64ad\u6d88\u606f<\/h6>\n

                    \u8c03\u7528 netlink_broadcast() \u51fd\u6570（\u539f\u578b\u89c1 3.2 \u8282）\u3002<\/p>\n

                    6.5 \u91ca\u653e\u5185\u6838 Netlink Socket<\/h5>\n

                    \u8c03\u7528 sock_release() \u51fd\u6570\u91ca\u653e Socket，\u793a\u4f8b\u5982\u4e0b： KaTeX parse error: Expected 'EOF', got '_' at position 11: \\\\text{sock_\u0332release(sk->sk_\u2026<\/span> \u5176\u4e2d，sk \u4e3a netlink_kernel_create() \u51fd\u6570\u7684\u8fd4\u56de\u503c\u3002<\/p>\n

                    6.6 \u793a\u4f8b\u7a0b\u5e8f\u8bf4\u660e<\/h5>\n

                    \u914d\u5957\u793a\u4f8b\u7a0b\u5e8f\u5305\u542b：<\/p>\n

                      \n
                    • \u5185\u6838\u6a21\u5757：netlink-exam-kern.c；<\/li>\n
                    • \u7528\u6237\u6001\u7a0b\u5e8f：netlink-exam-user-recv.c（\u63a5\u6536）\u3001netlink-exam-user-send.c（\u53d1\u9001）\u3002<\/li>\n<\/ul>\n

                      \u8fd0\u884c\u6d41\u7a0b：<\/p>\n

                    • \u52a0\u8f7d\u5185\u6838\u6a21\u5757；<\/li>\n
                    • \u7ec8\u7aef 1 \u8fd0\u884c\u63a5\u6536\u7a0b\u5e8f；<\/li>\n
                    • \u7ec8\u7aef 2 \u8fd0\u884c\u53d1\u9001\u7a0b\u5e8f（\u8bfb\u53d6\u6307\u5b9a\u6587\u672c\u6587\u4ef6，\u901a\u8fc7 Netlink \u53d1\u9001\u81f3\u5185\u6838）；<\/li>\n
                    • \u5185\u6838\u6a21\u5757\u63a5\u6536\u6d88\u606f\u540e，\u901a\u8fc7 \/proc\/netlink_exam_buffer \u66b4\u9732\u6570\u636e，\u5e76\u5c06\u6d88\u606f\u56de\u4f20\u7ed9\u63a5\u6536\u7a0b\u5e8f；<\/li>\n
                    • \u63a5\u6536\u7a0b\u5e8f\u6253\u5370\u6d88\u606f\u5185\u5bb9\u81f3\u5c4f\u5e55\u3002<\/li>\n

                      \u603b\u7ed3<\/h4>\n
                    • Netlink \u662f Linux \u7279\u6709\u7684\u57fa\u4e8e Socket \u7684\u53cc\u5411\u5f02\u6b65\u901a\u4fe1\u673a\u5236，\u652f\u6301\u591a\u64ad\u3001\u5185\u6838\u4e3b\u52a8\u53d1\u8d77\u4f1a\u8bdd，\u9002\u914d\u5185\u6838\u6001\u4e0e\u7528\u6237\u6001\u7684\u901a\u4fe1\u9700\u6c42，\u5728 2.6 \u53ca\u4ee5\u4e0a\u5185\u6838\u7248\u672c\u4e2d\u5e7f\u6cdb\u5e94\u7528；<\/li>\n
                    • \u7528\u6237\u6001\u901a\u8fc7\u6807\u51c6 Socket API（socket()\/bind()\/sendmsg()\/recvmsg()）\u4f7f\u7528 Netlink，\u5185\u6838\u6001\u9700\u8c03\u7528\u4e13\u7528 API（netlink_kernel_create()\/netlink_unicast() \u7b49）；<\/li>\n
                    • Netlink \u6d88\u606f\u7531 nlmsghdr \u5934\u548c\u8f7d\u8377\u7ec4\u6210，\u53ef\u901a\u8fc7\u5185\u6838\u9884\u5b9a\u4e49\u5b8f\u7b80\u5316\u6d88\u606f\u957f\u5ea6\u8ba1\u7b97\u3001\u8f7d\u8377\u89e3\u6790\u7b49\u64cd\u4f5c，\u76f8\u8f83\u4e8e\u7cfb\u7edf\u8c03\u7528\u3001ioctl \u7b49\u673a\u5236\u5177\u5907\u5f00\u53d1\u6210\u672c\u4f4e\u3001\u6027\u80fd\u4f18\u3001\u7075\u6d3b\u6027\u9ad8\u7684\u7279\u70b9\u3002<\/li>\n
                      \n

                      Linux \u5185\u6838 netlink \u673a\u5236 – \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u6570\u636e\u4f20\u8f93<\/h2>\n

                      hinewcc \u539f\u521b\u5df2\u4e8e 2024-12-31 09:49:56 \u4fee\u6539<\/p>\n

                      1 \u7b80\u4ecb<\/h3>\n

                      Netlink socket \u662f Linux \u7cfb\u7edf\u7279\u6709\u7684\u5957\u63a5\u5b57\u7c7b\u578b，\u662f\u5b9e\u73b0\u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u8fdb\u7a0b\u95f4\u901a\u4fe1（Inter-Process Communication, IPC）\u7684\u4e13\u7528\u673a\u5236，\u540c\u65f6\u4e5f\u662f\u7f51\u7edc\u5e94\u7528\u7a0b\u5e8f\u4e0e\u5185\u6838\u8fdb\u884c\u4ea4\u4e92\u7684\u4e3b\u6d41\u63a5\u53e3\u3002 Netlink \u4e3a\u5185\u6838\u4e0e\u7528\u6237\u6001\u5e94\u7528\u4e4b\u95f4\u7684\u53cc\u5411\u6570\u636e\u4f20\u8f93\u63d0\u4f9b\u4e86\u9ad8\u6548\u7684\u5b9e\u73b0\u65b9\u5f0f：\u7528\u6237\u6001\u5e94\u7528\u53ef\u901a\u8fc7\u6807\u51c6\u7684 socket API \u8c03\u7528 Netlink \u63d0\u4f9b\u7684\u529f\u80fd，\u800c\u5185\u6838\u6001\u9700\u501f\u52a9\u4e13\u7528\u7684\u5185\u6838 API \u5b8c\u6210 Netlink \u76f8\u5173\u64cd\u4f5c\u3002Netlink \u63a5\u53e3\u5206\u4e3a\u5e94\u7528\u5c42\u63a5\u53e3\u4e0e\u5185\u6838\u63a5\u53e3\u4e24\u7c7b，\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d，\u9700\u4e8e\u5e94\u7528\u7a0b\u5e8f\u4fa7\u5b9e\u73b0\u7b56\u7565\u903b\u8f91，\u5e76\u5728\u5185\u6838\u4fa7\u5b9e\u73b0\u5e95\u5c42\u673a\u5236\u3002<\/p>\n

                      \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u7684\u5e38\u7528\u901a\u4fe1\u65b9\u5f0f\u5305\u542b\u4ee5\u4e0b\u4e09\u7c7b：proc \u6587\u4ef6\u7cfb\u7edf\u3001ioctl \u8c03\u7528\u3001Netlink \u673a\u5236： （1）\/proc \u6587\u4ef6\u7cfb\u7edf – \u5355\u5411\u901a\u4fe1：\u4f5c\u4e3a\u865a\u62df\u6587\u4ef6\u7cfb\u7edf，\u4e3b\u8981\u7528\u4e8e\u7528\u6237\u7a7a\u95f4\u4ece\u5185\u6838\u83b7\u53d6\u4fe1\u606f\u3001\u8f93\u51fa\u6570\u636e； （2）ioctl \u8c03\u7528 – \u5355\u5411\u901a\u4fe1：\u4e0d\u652f\u6301\u5f02\u6b65\u4fe1\u606f\u53d1\u9001，\u4ec5\u7528\u4e8e\u7528\u6237\u7a7a\u95f4\u5411\u5185\u6838\u4f20\u9012\u63a7\u5236\u547d\u4ee4； （3）Netlink \u673a\u5236 – \u53cc\u5411\u901a\u4fe1：\u5185\u6838\u53ef\u4e3b\u52a8\u53d1\u8d77\u6570\u636e\u4f20\u8f93，\u800c\u975e\u4ec5\u54cd\u5e94\u7528\u6237\u7a7a\u95f4\u8bf7\u6c42\u5e76\u8fd4\u56de\u4fe1\u606f\u3002<\/p>\n

                      1.1 netlink \u673a\u5236\u7684\u4f18\u52bf<\/h4>\n
                        \n
                      • \u652f\u6301\u5168\u53cc\u5de5\u3001\u5f02\u6b65\u901a\u4fe1\u6a21\u5f0f；<\/li>\n
                      • \u7528\u6237\u7a7a\u95f4\u53ef\u76f4\u63a5\u4f7f\u7528\u6807\u51c6 socket \u63a5\u53e3\u5b8c\u6210\u901a\u4fe1\u64cd\u4f5c；<\/li>\n
                      • \u5177\u5907\u591a\u64ad\u901a\u4fe1\u80fd\u529b；<\/li>\n
                      • \u5185\u6838\u7aef\u53ef\u5728\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u4e0e\u4e2d\u65ad\u4e0a\u4e0b\u6587\u73af\u5883\u4e2d\u4f7f\u7528\u3002<\/li>\n<\/ul>\n

                        1.2 netlink \u673a\u5236\u7684\u5178\u578b\u5e94\u7528\u573a\u666f<\/h4>\n
                          \n
                        • \u83b7\u53d6\u6216\u4fee\u6539\u7cfb\u7edf\u8def\u7531\u4fe1\u606f；<\/li>\n
                        • \u76d1\u542c TCP \u534f\u8bae\u6570\u636e\u62a5\u6587；<\/li>\n
                        • \u9632\u706b\u5899\u529f\u80fd\u5b9e\u73b0；<\/li>\n
                        • netfilter \u5b50\u7cfb\u7edf\u4ea4\u4e92；<\/li>\n
                        • \u5185\u6838\u4e8b\u4ef6\u5411\u7528\u6237\u6001\u7684\u4e3b\u52a8\u901a\u77e5\u3002<\/li>\n<\/ul>\n

                          2 netlink \u5e38\u7528\u6570\u636e\u7ed3\u6784\u53ca\u51fd\u6570<\/h3>\n

                          2.1 netlink \u5e94\u7528\u5c42\u6570\u636e\u7ed3\u6784\u53ca\u51fd\u6570<\/h4>\n

                          \u5728\u7f51\u7edc\u7f16\u7a0b\u4e2d，\u901a\u5e38\u901a\u8fc7 IP \u5730\u5740 + \u7aef\u53e3\u53f7 \u5b8c\u6210\u5bfb\u5740\u64cd\u4f5c；\u800c netlink \u673a\u5236\u5219\u901a\u8fc7 \u534f\u8bae\u7c7b\u578b + \u8fdb\u7a0b ID \u5b9e\u73b0\u5bfb\u5740，\u5176\u4e2d \u534f\u8bae\u7c7b\u578b \u9700\u5728\u8c03\u7528 socket \u63a5\u53e3 \u65f6\u6307\u5b9a\u3002<\/p>\n

                          2.1.1 \u6d88\u606f\u7ed3\u6784<\/h5>\n

                          netlink \u6d88\u606f\u7531\u6d88\u606f\u5934\u4e0e\u6d88\u606f\u4f53\u4e24\u90e8\u5206\u7ec4\u6210：\u6d88\u606f\u5934\u56fa\u5b9a\u5360\u7528 16 \u5b57\u8282，\u5176\u540e\u7d27\u8ddf\u6d88\u606f\u4f53（\u6709\u6548\u6570\u636e）\u3002<\/p>\n

                          \"img\"<\/p>\n

                            \n
                          • Message Length：\u6d88\u606f\u603b\u957f\u5ea6，\u5305\u542b netlink \u6d88\u606f\u5934\u5728\u5185\u7684\u5168\u90e8\u5b57\u8282\u6570，\u5360\u7528 4 \u5b57\u8282；<\/li>\n
                          • Type：\u6d88\u606f\u7c7b\u578b，\u591a\u7528\u4e8e\u534f\u8bae\u4ea4\u4e92\u6d41\u7a0b，\u5185\u6838\u5b9a\u4e49\u4e86\u82e5\u5e72\u6807\u51c6\u6d88\u606f\u7c7b\u578b，\u4e14\u5df2\u57fa\u4e8e netlink \u5b9e\u73b0\u591a\u79cd\u534f\u8bae，\u6bcf\u79cd\u534f\u8bae\u5bf9\u5e94\u7279\u5b9a\u7684\u7c7b\u578b\u4e0e\u529f\u80fd，\u5360\u7528 2 \u5b57\u8282；<\/li>\n
                          • Flags：\u6d88\u606f\u6807\u5fd7\u4f4d，\u5360\u7528 2 \u5b57\u8282；<\/li>\n
                          • Sequence number：\u5e8f\u5217\u53f7，\u4e3a\u53ef\u9009\u5b57\u6bb5，\u529f\u80fd\u7c7b\u6bd4 TCP \u534f\u8bae\u4e2d\u7684\u62a5\u6587\u5e8f\u53f7，\u5360\u7528 4 \u5b57\u8282；<\/li>\n
                          • PID（port ID）：\u7aef\u53e3\u6807\u8bc6，\u5373\u53d1\u9001\u7aef\u7684\u7aef\u53e3 ID \u53f7，\u5360\u7528 4 \u5b57\u8282\u3002<\/li>\n<\/ul>\n
                            \u6d88\u606f\u5934 nlmsghdr \u7ed3\u6784\u4f53\u5b9a\u4e49：<\/h6>\n

                            struct<\/span> nlmsghdr<\/span> {<\/span>
                            \n __u32 nlmsg_len;<\/span> \/* \u5305\u62ec netlink \u6d88\u606f\u5934\u5728\u5185，\u6574\u4e2a\u6d88\u606f\u7684\u603b\u957f\u5ea6 *\/<\/span>
                            \n __u16 nlmsg_type;<\/span> \/* \u6d88\u606f\u7c7b\u578b *\/<\/span>
                            \n __u16 nlmsg_flags;<\/span> \/* \u6d88\u606f\u6807\u5fd7\u4f4d *\/<\/span>
                            \n __u32 nlmsg_seq;<\/span> \/* \u6d88\u606f\u62a5\u6587\u7684\u5e8f\u5217\u53f7 *\/<\/span>
                            \n __u32 nlmsg_pid;<\/span> \/* \u53d1\u9001\u7aef\u53e3\u7684 ID \u53f7：\u5185\u6838\u4fa7\u8be5\u503c\u4e3a 0，\u7528\u6237\u8fdb\u7a0b\u4fa7\u4e3a\u5176 socket \u7ed1\u5b9a\u7684 ID \u53f7 *\/<\/span>
                            \n}<\/span>;<\/span><\/p>\n

                            2.1.2 netlink \u901a\u4fe1\u5730\u5740 struct sockaddr_nl<\/h5>\n

                            struct sockaddr_nl \u662f netlink \u673a\u5236\u7684\u901a\u4fe1\u5730\u5740\u7ed3\u6784\u4f53，\u529f\u80fd\u7c7b\u6bd4\u666e\u901a socket \u7f16\u7a0b\u4e2d\u7684 struct sockaddr_in \u7ed3\u6784\u4f53：<\/p>\n

                            struct<\/span> sockaddr_nl<\/span> {<\/span>
                            \n __kernel_sa_family_t nl_family;<\/span> \/* \u5730\u5740\u65cf，\u56fa\u5b9a\u4e3a AF_NETLINK *\/<\/span>
                            \n unsigned<\/span> short<\/span> nl_pad;<\/span> \/* \u9884\u7559\u586b\u5145\u5b57\u6bb5，\u6682\u672a\u4f7f\u7528，\u9700\u7f6e\u4e3a 0 *\/<\/span>
                            \n __u32 nl_pid;<\/span> \/* \u7aef\u53e3 ID（\u901a\u4fe1\u7aef\u53e3\u53f7），0 \u8868\u793a\u76ee\u6807\u4e3a\u5185\u6838 *\/<\/span>
                            \n __u32 nl_groups;<\/span> \/* \u591a\u64ad\u7ec4\u63a9\u7801 *\/<\/span>
                            \n}<\/span>;<\/span><\/p>\n

                            nl_groups \u4e3a\u591a\u64ad\u7ec4\u7684\u5730\u5740\u63a9\u7801（\u975e\u591a\u64ad\u7ec4\u7f16\u53f7），\u53ef\u53c2\u8003\u5185\u6838\u6e90\u7801\u6587\u4ef6 net\/netlink\/af_netlink.c \u4e2d\u7684\u5982\u4e0b\u51fd\u6570：<\/p>\n

                            static<\/span> u32 netlink_group_mask<\/span>(<\/span>u32 group)<\/span>
                            \n{<\/span>
                            \n return<\/span> group ?<\/span> 1<\/span> <<<\/span> (<\/span>group –<\/span> 1<\/span>)<\/span> :<\/span> 0<\/span>;<\/span>
                            \n}<\/span><\/p>\n

                            \u5373\u7528\u6237\u7a7a\u95f4\u4ee3\u7801\u4e2d，\u82e5\u9700\u52a0\u5165\u591a\u64ad\u7ec4 1，\u9700\u5c06 nl_groups \u8bbe\u4e3a 1；\u591a\u64ad\u7ec4 2 \u5bf9\u5e94\u7684\u63a9\u7801\u4e3a 2；\u591a\u64ad\u7ec4 3 \u5bf9\u5e94\u7684\u63a9\u7801\u4e3a 4，\u4f9d\u6b64\u7c7b\u63a8\u3002nl_groups \u4e3a 0 \u65f6，\u8868\u793a\u4e0d\u52a0\u5165\u4efb\u4f55\u591a\u64ad\u7ec4\u3002<\/p>\n

                            nl_groups \u591a\u64ad\u7ec4\u63a9\u7801\u4e3a 32 \u4f4d\u6574\u578b，\u6bcf 1 \u4e2a\u6bd4\u7279\u4f4d\u5bf9\u5e94 1 \u4e2a\u591a\u64ad\u7ec4，\u56e0\u6b64\u6bcf\u79cd Netlink \u534f\u8bae\u6700\u591a\u652f\u6301 32 \u4e2a\u591a\u64ad\u7ec4\u3002\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u82e5\u5173\u6ce8\u67d0\u4e00\u591a\u64ad\u7ec4，\u53ef\u52a0\u5165\u8be5\u7ec4；\u5f53\u5185\u6838\u7a7a\u95f4\u8fdb\u7a0b\u5411\u8be5\u7ec4\u53d1\u9001\u591a\u64ad\u6d88\u606f\u65f6，\u6240\u6709\u5df2\u52a0\u5165\u8be5\u7ec4\u7684\u7528\u6237\u8fdb\u7a0b\u5747\u53ef\u63a5\u6536\u6b64\u6d88\u606f\u3002<\/p>\n

                            2.2 netlink \u5185\u6838\u5c42\u6570\u636e\u7ed3\u6784\u53ca\u51fd\u6570<\/h4>\n

                            2.2.1 \u5e38\u7528\u5b8f\u5b9a\u4e49<\/h5>\n

                            netlink \u6d88\u606f\u7c7b\u578b\u53ca\u5e38\u7528\u64cd\u4f5c\u5b8f\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

                            \/******************** netlink \u6d88\u606f\u7c7b\u578b ********************\/<\/span>
                            \n#<\/span>define<\/span> NETLINK_ROUTE<\/span> 0<\/span> <\/span>\/* \u8def\u7531\/\u8bbe\u5907\u94a9\u5b50\u51fd\u6570\u63a5\u53e3 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_UNUSED<\/span> 1<\/span> <\/span>\/* \u672a\u4f7f\u7528\u7f16\u53f7 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_USERSOCK<\/span> 2<\/span> <\/span>\/* \u4e3a\u7528\u6237\u6001 socket \u534f\u8bae\u9884\u7559 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_FIREWALL<\/span> 3<\/span> <\/span>\/* \u672a\u4f7f\u7528\u7f16\u53f7，\u539f\u7528\u4e8e ip_queue \u6a21\u5757 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_SOCK_DIAG<\/span> 4<\/span> <\/span>\/* socket \u76d1\u63a7\u63a5\u53e3 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_NFLOG<\/span> 5<\/span> <\/span>\/* netfilter\/iptables ULOG \u6a21\u5757 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_XFRM<\/span> 6<\/span> <\/span>\/* IPsec \u534f\u8bae\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_SELINUX<\/span> 7<\/span> <\/span>\/* SELinux \u4e8b\u4ef6\u901a\u77e5 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_ISCSI<\/span> 8<\/span> <\/span>\/* Open-iSCSI \u534f\u8bae\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_AUDIT<\/span> 9<\/span> <\/span>\/* \u5ba1\u8ba1\u529f\u80fd\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_FIB_LOOKUP<\/span> 10<\/span> <\/span>\/* FIB \u67e5\u8868\u529f\u80fd\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_CONNECTOR<\/span> 11<\/span> <\/span>\/* \u8fde\u63a5\u5668\u5b50\u7cfb\u7edf\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_NETFILTER<\/span> 12<\/span> <\/span>\/* netfilter \u5b50\u7cfb\u7edf *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_IP6_FW<\/span> 13<\/span> <\/span>\/* IPv6 \u9632\u706b\u5899\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_DNRTMSG<\/span> 14<\/span> <\/span>\/* DECnet \u8def\u7531\u6d88\u606f *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_KOBJECT_UEVENT<\/span> 15<\/span> <\/span>\/* \u5185\u6838\u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u7684\u5bf9\u8c61\u4e8b\u4ef6\u6d88\u606f *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_GENERIC<\/span> 16<\/span> <\/span>\/* \u901a\u7528\u578b netlink \u534f\u8bae *\/<\/span><\/span>
                            \n\/* \u4e3a NETLINK_DM（DM \u4e8b\u4ef6）\u9884\u7559\u7a7a\u95f4 *\/<\/span>
                            \n#<\/span>define<\/span> NETLINK_SCSITRANSPORT<\/span> 18<\/span> <\/span>\/* SCSI \u4f20\u8f93\u5c42\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_ECRYPTFS<\/span> 19<\/span> <\/span>\/* ECRYPTFS \u52a0\u5bc6\u6587\u4ef6\u7cfb\u7edf\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_RDMA<\/span> 20<\/span> <\/span>\/* RDMA \u534f\u8bae\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_CRYPTO<\/span> 21<\/span> <\/span>\/* \u52a0\u5bc6\u5c42\u76f8\u5173 *\/<\/span><\/span>
                            \n#<\/span>define<\/span> NETLINK_INET_DIAG<\/span> NETLINK_SOCK_DIAG <\/span>\/* \u7f51\u7edc\u5957\u63a5\u5b57\u8bca\u65ad *\/<\/span><\/span>
                            \n#<\/span>define<\/span> MAX_LINKS<\/span> 32<\/span> <\/span>\/* \u6700\u5927\u652f\u6301\u7684 netlink \u94fe\u8def\u6570 *\/<\/span><\/span><\/p>\n

                            \/******************** netlink \u5e38\u7528\u5b8f ********************\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_ALIGNTO<\/span> 4U<\/span> <\/span>\/* \u5b57\u8282\u5bf9\u9f50\u57fa\u51c6\u503c *\/<\/span><\/span>
                            \n\/* \u8ba1\u7b97\u4e0d\u5c0f\u4e8e len \u4e14\u6ee1\u8db3\u5b57\u8282\u5bf9\u9f50\u7684\u6700\u5c0f\u6570\u503c *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_ALIGN<\/span>(<\/span>len)<\/span> (<\/span> (<\/span>(<\/span>len)<\/span>+<\/span>NLMSG_ALIGNTO–<\/span>1<\/span>)<\/span> &<\/span> ~<\/span>(<\/span>NLMSG_ALIGNTO–<\/span>1<\/span>)<\/span> )<\/span><\/span><\/span>
                            \n\/* Netlink \u6d88\u606f\u5934\u957f\u5ea6 *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_HDRLEN<\/span> (<\/span>(<\/span>int<\/span>)<\/span> NLMSG_ALIGN<\/span>(<\/span>sizeof<\/span>(<\/span>struct<\/span> nlmsghdr<\/span>)<\/span>)<\/span>)<\/span><\/span><\/span>
                            \n\/* \u8ba1\u7b97\u5305\u542b\u6d88\u606f\u5934\u7684\u6d88\u606f\u603b\u957f\u5ea6（\u6d88\u606f\u4f53\u957f\u5ea6 + \u6d88\u606f\u5934\u957f\u5ea6）*\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_LENGTH<\/span>(<\/span>len)<\/span> (<\/span>(<\/span>len)<\/span> +<\/span> NLMSG_HDRLEN)<\/span><\/span><\/span>
                            \n\/* \u8fd4\u56de\u4e0d\u5c0f\u4e8e NLMSG_LENGTH(len) \u4e14\u6ee1\u8db3\u5b57\u8282\u5bf9\u9f50\u7684\u6700\u5c0f\u6570\u503c *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_SPACE<\/span>(<\/span>len)<\/span> NLMSG_ALIGN<\/span>(<\/span>NLMSG_LENGTH<\/span>(<\/span>len)<\/span>)<\/span><\/span><\/span>
                            \n\/* \u83b7\u53d6\u6d88\u606f\u4f53\u6570\u636e\u90e8\u5206\u7684\u9996\u5730\u5740，\u8bfb\u5199\u6d88\u606f\u6570\u636e\u65f6\u8c03\u7528 *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_DATA<\/span>(<\/span>nlh)<\/span> (<\/span>(<\/span>void<\/span>*<\/span>)<\/span>(<\/span>(<\/span>(<\/span>char<\/span>*<\/span>)<\/span>nlh)<\/span> +<\/span> NLMSG_LENGTH<\/span>(<\/span>0<\/span>)<\/span>)<\/span>)<\/span><\/span><\/span>
                            \n\/* \u83b7\u53d6\u4e0b\u4e00\u4e2a\u6d88\u606f\u7684\u9996\u5730\u5740，\u540c\u65f6\u66f4\u65b0 len \u4e3a\u5269\u4f59\u6d88\u606f\u957f\u5ea6 *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_NEXT<\/span>(<\/span>nlh,<\/span>len)<\/span> (<\/span>(<\/span>len)<\/span> -=<\/span> NLMSG_ALIGN<\/span>(<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg_len)<\/span>,<\/span> <\/span>\\\\<\/span>
                            \n (<\/span>struct<\/span> nlmsghdr<\/span>*<\/span>)<\/span>(<\/span>(<\/span>(<\/span>char<\/span>*<\/span>)<\/span>(<\/span>nlh)<\/span>)<\/span> +<\/span> NLMSG_ALIGN<\/span>(<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg_len)<\/span>)<\/span>)<\/span><\/span><\/span>
                            \n\/* \u5224\u65ad\u6d88\u606f\u957f\u5ea6\u662f\u5426\u5408\u6cd5 *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_OK<\/span>(<\/span>nlh,<\/span>len)<\/span> (<\/span>(<\/span>len)<\/span> >=<\/span> (<\/span>int<\/span>)<\/span>sizeof<\/span>(<\/span>struct<\/span> nlmsghdr<\/span>)<\/span> &&<\/span> <\/span>\\\\<\/span>
                            \n (<\/span>nlh)<\/span>-><\/span>nlmsg_len >=<\/span> sizeof<\/span>(<\/span>struct<\/span> nlmsghdr<\/span>)<\/span> &&<\/span> <\/span>\\\\<\/span>
                            \n (<\/span>nlh)<\/span>-><\/span>nlmsg_len <=<\/span> (<\/span>len)<\/span>)<\/span><\/span><\/span>
                            \n\/* \u8ba1\u7b97\u6d88\u606f\u8f7d\u8377（payload）\u7684\u957f\u5ea6 *\/<\/span>
                            \n#<\/span>define<\/span> NLMSG_PAYLOAD<\/span>(<\/span>nlh,<\/span>len)<\/span> (<\/span>(<\/span>nlh)<\/span>-><\/span>nlmsg_len –<\/span> NLMSG_SPACE<\/span>(<\/span>(<\/span>len)<\/span>)<\/span>)<\/span><\/span><\/span><\/p>\n

                            2.2.2 \u5e38\u7528\u51fd\u6570<\/h5>\n
                            （1）netlink_kernel_create \u51fd\u6570<\/h6>\n

                            \u51fd\u6570\u539f\u578b：<\/p>\n

                            static<\/span> inline<\/span> struct<\/span> sock<\/span> *<\/span>
                            \nnetlink_kernel_create<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> unit,<\/span> struct<\/span> netlink_kernel_cfg<\/span> *<\/span>cfg)<\/span><\/p>\n

                            \u529f\u80fd：\u521b\u5efa\u5185\u6838\u6001 socket，\u7528\u4e8e\u5b9e\u73b0\u4e0e\u7528\u6237\u6001\u7684\u901a\u4fe1\u3002 \u53c2\u6570\u8bf4\u660e：<\/p>\n

                              \n
                            • net：\u6307\u5411\u7f51\u7edc\u547d\u540d\u7a7a\u95f4（namespace）\u7684\u6307\u9488，\u9ed8\u8ba4\u573a\u666f\u4e0b\u4f20\u5165\u5168\u5c40\u53d8\u91cf &init_net（\u65e0\u9700\u989d\u5916\u5b9a\u4e49）；<\/li>\n
                            • unit：netlink \u534f\u8bae\u7c7b\u578b，\u5982 NETLINK_TEST\u3001NETLINK_SELINUX \u7b49；<\/li>\n
                            • cfg：\u5b58\u653e netlink \u5185\u6838\u914d\u7f6e\u53c2\u6570\u7684\u7ed3\u6784\u4f53（\u5b9a\u4e49\u5982\u4e0b）\u3002<\/li>\n<\/ul>\n

                              struct<\/span> netlink_kernel_cfg<\/span> {<\/span>
                              \n unsigned<\/span> int<\/span> groups;<\/span> \/\/ \u8be5\u534f\u8bae\u7c7b\u578b\u652f\u6301\u7684\u6700\u5927\u591a\u64ad\u7ec4\u6570\u91cf，\u82e5\u5c0f\u4e8e 32 \u5219\u9ed8\u8ba4\u6309 32 \u5904\u7406，\u901a\u5e38\u7f6e\u4e3a 0<\/span>
                              \n unsigned<\/span> int<\/span> flags;<\/span> \/\/ \u914d\u7f6e\u6807\u5fd7\u4f4d<\/span>
                              \n void<\/span> (<\/span>*<\/span>input)<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>;<\/span> \/\/ \u6d88\u606f\u63a5\u6536\u56de\u8c03\u51fd\u6570<\/span>
                              \n struct<\/span> mutex<\/span> *<\/span>cb_mutex;<\/span> \/\/ \u56de\u8c03\u51fd\u6570\u4e92\u65a5\u9501<\/span>
                              \n int<\/span> (<\/span>*<\/span>bind)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> group)<\/span>;<\/span> \/\/ \u7ed1\u5b9a\u56de\u8c03\u51fd\u6570<\/span>
                              \n void<\/span> (<\/span>*<\/span>unbind)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> group)<\/span>;<\/span> \/\/ \u89e3\u7ed1\u56de\u8c03\u51fd\u6570<\/span>
                              \n bool<\/span> (<\/span>*<\/span>compare)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> struct<\/span> sock<\/span> *<\/span>sk)<\/span>;<\/span> \/\/ \u6bd4\u8f83\u51fd\u6570<\/span>
                              \n}<\/span>;<\/span><\/p>\n

                              （2）\u5355\u64ad\u51fd\u6570 netlink_unicast()<\/h6>\n

                              \u51fd\u6570\u539f\u578b：<\/p>\n

                              int<\/span> netlink_unicast<\/span>(<\/span>struct<\/span> sock<\/span> *<\/span>ssk,<\/span> struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> __u32 portid,<\/span> int<\/span> nonblock)<\/span><\/p>\n

                              \u529f\u80fd：\u5411\u6307\u5b9a\u7aef\u53e3\u53d1\u9001\u5355\u64ad\u6d88\u606f\u3002 \u53c2\u6570\u8bf4\u660e：<\/p>\n

                                \n
                              • ssk：netlink socket \u6307\u9488（netlink_kernel_create \u51fd\u6570\u7684\u8fd4\u56de\u503c）；<\/li>\n
                              • skb：\u5185\u6838\u5957\u63a5\u5b57\u7f13\u51b2\u533a（sk_buff）\u6307\u9488；<\/li>\n
                              • portid：\u76ee\u6807\u901a\u4fe1\u7aef\u53e3\u53f7（\u63a5\u6536\u6d88\u606f\u7684\u8fdb\u7a0b PID）；<\/li>\n
                              • nonblock：\u975e\u963b\u585e\u6807\u5fd7\u4f4d，1 \u8868\u793a\u65e0\u53ef\u7528\u63a5\u6536\u7f13\u5b58\u65f6\u7acb\u5373\u8fd4\u56de，0 \u8868\u793a\u65e0\u53ef\u7528\u63a5\u6536\u7f13\u5b58\u65f6\u7761\u7720\u7b49\u5f85\u3002<\/li>\n<\/ul>\n
                                （3）\u591a\u64ad\u51fd\u6570 netlink_broadcast()<\/h6>\n

                                \u51fd\u6570\u539f\u578b：<\/p>\n

                                int<\/span> netlink_broadcast<\/span>(<\/span>struct<\/span> sock<\/span> *<\/span>ssk,<\/span> struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> __u32 portid,<\/span>
                                \n __u32 group,<\/span> gfp_t allocation)<\/span><\/p>\n

                                \u529f\u80fd：\u5411\u6307\u5b9a\u591a\u64ad\u7ec4\u53d1\u9001\u591a\u64ad\u6d88\u606f\u3002 \u53c2\u6570\u8bf4\u660e：<\/p>\n

                                  \n
                                • ssk：netlink socket \u6307\u9488（netlink_kernel_create \u51fd\u6570\u7684\u8fd4\u56de\u503c）；<\/li>\n
                                • skb：\u5185\u6838\u5957\u63a5\u5b57\u7f13\u51b2\u533a（sk_buff）\u6307\u9488；<\/li>\n
                                • portid：\u53d1\u9001\u7aef\u7aef\u53e3 ID；<\/li>\n
                                • group：\u76ee\u6807\u591a\u64ad\u7ec4\u63a9\u7801\u7684\u6309\u4f4d\u6216\u7ed3\u679c；<\/li>\n
                                • allocation：\u5185\u6838\u5185\u5b58\u5206\u914d\u65b9\u5f0f\u6807\u8bc6，\u4e2d\u65ad\u4e0a\u4e0b\u6587\u901a\u5e38\u4f7f\u7528 GFP_ATOMIC，\u5176\u4ed6\u573a\u666f\u4f7f\u7528 GFP_KERNEL；\u8be5\u53c2\u6570\u5b58\u5728\u7684\u539f\u56e0\u662f\u8be5 API \u53ef\u80fd\u9700\u8981\u5206\u914d\u7f13\u51b2\u533a\u4ee5\u514b\u9686\u591a\u64ad\u6d88\u606f\u3002<\/li>\n<\/ul>\n

                                  3 \u4ee3\u7801\u5b9e\u4f8b<\/h3>\n

                                  \u4ee5\u4e0b\u4ee3\u7801\u793a\u4f8b\u5206\u522b\u5b9e\u73b0\u7528\u6237\u6001\u4e0e\u5185\u6838\u6001\u7684 netlink \u901a\u4fe1\u903b\u8f91\u3002<\/p>\n

                                  3.1 \u7528\u6237\u6001 netlink \u7a0b\u5e8f<\/h4>\n

                                  3.1.1 netlink \u5e94\u7528\u5c42\u7f16\u7a0b\u57fa\u672c\u6b65\u9aa4<\/h5>\n
                                  （1）\u521b\u5efa\u5957\u63a5\u5b57<\/h6>\n

                                  \u51fd\u6570\u539f\u578b：<\/p>\n

                                  int<\/span> socket<\/span>(<\/span>int<\/span> domain,<\/span> int<\/span> type,<\/span> int<\/span> protocol)<\/span><\/p>\n

                                  \u53c2\u6570\u8bf4\u660e：<\/p>\n

                                    \n
                                  • domain：\u534f\u8bae\u65cf，netlink \u673a\u5236\u4e2d\u56fa\u5b9a\u4e3a AF_NETLINK；<\/li>\n
                                  • type：\u5957\u63a5\u5b57\u7c7b\u578b，netlink \u673a\u5236\u4e2d\u56fa\u5b9a\u4e3a SOCK_RAW；<\/li>\n
                                  • protocol：\u534f\u8bae\u7c7b\u578b，\u53ef\u4f7f\u7528\u5185\u6838\u9884\u5b9a\u4e49\u534f\u8bae\u6216\u81ea\u5b9a\u4e49\u534f\u8bae\u3002<\/li>\n<\/ul>\n

                                    \u81ea\u5b9a\u4e49\u534f\u8bae\u793a\u4f8b：<\/p>\n

                                    #<\/span>define<\/span> NETLINK_TEST<\/span> 23<\/span> <\/span>\/\/ \u81ea\u5b9a\u4e49 netlink \u534f\u8bae\u7c7b\u578b<\/span><\/span>
                                    \n.<\/span>.<\/span>.<\/span>.<\/span>.<\/span>.<\/span>
                                    \nint<\/span> skfd =<\/span> 0<\/span>;<\/span>
                                    \nskfd =<\/span> socket<\/span>(<\/span>AF_NETLINK,<\/span> SOCK_RAW,<\/span> NETLINK_TEST)<\/span>;<\/span><\/p>\n

                                    （2）\u7ed1\u5b9a\u672c\u5730\u5730\u5740\u5230\u5957\u63a5\u5b57<\/h6>\n

                                    \u51fd\u6570\u539f\u578b：<\/p>\n

                                    int<\/span> bind<\/span>(<\/span>int<\/span> sockfd,<\/span> const<\/span> struct<\/span> sockaddr<\/span> *<\/span>addr,<\/span> socklen_t addrlen)<\/span> \/\/ \u5730\u5740\u7ed1\u5b9a<\/span>
                                    \n\/* sockaddr_nl \u662f netlink \u4e13\u7528\u5730\u5740\u7ed3\u6784\u4f53，\u533a\u522b\u4e8e\u7f51\u7edc\u7f16\u7a0b\u7684\u901a\u7528\u5730\u5740\u7ed3\u6784 *\/<\/span>
                                    \nstruct<\/span> sockaddr_nl<\/span> {<\/span>
                                    \n __kernel_sa_family_t nl_family;<\/span> \/\/ \u5730\u5740\u65cf，\u56fa\u5b9a\u4e3a AF_NETLINK<\/span>
                                    \n unsigned<\/span> short<\/span> nl_pad;<\/span> \/\/ \u586b\u5145\u5b57\u6bb5，\u65e0\u9700\u8d4b\u503c<\/span>
                                    \n __u32 nl_pid;<\/span> \/\/ \u4e0e\u5185\u6838\u901a\u4fe1\u7684\u8fdb\u7a0b PID，0 \u8868\u793a\u76ee\u6807\u4e3a\u5185\u6838<\/span>
                                    \n __u32 nl_groups;<\/span> \/\/ \u591a\u64ad\u7ec4\u5730\u5740\u63a9\u7801，netlink \u652f\u6301\u591a\u64ad\u901a\u4fe1<\/span>
                                    \n}<\/span>;<\/span><\/p>\n

                                    \u7ed1\u5b9a\u793a\u4f8b：<\/p>\n

                                    struct<\/span> sockaddr_nl<\/span> nlsrc_addr =<\/span> {<\/span>0<\/span>}<\/span>;<\/span>
                                    \n\/* \u521d\u59cb\u5316\u672c\u5730 socket \u5730\u5740 *\/<\/span>
                                    \nnlsrc_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
                                    \nnlsrc_addr.<\/span>nl_pid =<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span>
                                    \nnlsrc_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span>
                                    \n\/* \u6267\u884c\u5730\u5740\u7ed1\u5b9a *\/<\/span>
                                    \nif<\/span>(<\/span>bind<\/span>(<\/span>skfd,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>nlsrc_addr,<\/span> addr_len)<\/span> !=<\/span> 0<\/span>)<\/span>
                                    \n{<\/span>
                                    \n printf<\/span>(<\/span>"bind addr error\\\\n"<\/span>)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n}<\/span><\/p>\n

                                    （3）\u6784\u9020\u901a\u4fe1\u6d88\u606f<\/h6>\n
                                    （4）\u53d1\u9001\/\u63a5\u6536\u6d88\u606f<\/h6>\n

                                    netlink \u673a\u5236\u63d0\u4f9b\u4e24\u5957\u6536\u53d1\u6d88\u606f\u7684\u63a5\u53e3：sendto\/recvfrom\u3001sendmsg\/recvmsg\u3002\u6838\u5fc3\u63a5\u53e3\u5b9a\u4e49\u5982\u4e0b：<\/p>\n

                                    ssize_t sendto<\/span>(<\/span>int<\/span> sockfd,<\/span> const<\/span> void<\/span> *<\/span>buf,<\/span> size_t len,<\/span> int<\/span> flags,<\/span> const<\/span> struct<\/span> sockaddr<\/span> *<\/span>dest_addr,<\/span> socklen_t addrlen)<\/span>;<\/span>
                                    \nssize_t recvfrom<\/span>(<\/span>int<\/span> sockfd,<\/span> void<\/span> *<\/span>buf,<\/span> size_t len,<\/span> int<\/span> flags,<\/span> struct<\/span> sockaddr<\/span> *<\/span>src_addr,<\/span> socklen_t *<\/span>addrlen)<\/span>;<\/span><\/p>\n

                                    3.1.2 netlink \u7528\u6237\u7a7a\u95f4\u5b8c\u6574\u4ee3\u7801<\/h5>\n

                                    #<\/span>include<\/span> <stdio.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <stdlib.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <sys\/socket.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <string.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span>
                                    \n#<\/span>define<\/span> NETLINK_TEST<\/span> 17<\/span><\/span><\/span>
                                    \n#<\/span>define<\/span> RX_BUF_SIZE<\/span> 100<\/span> <\/span>\/\/ \u63a5\u6536\u7f13\u51b2\u533a\u5927\u5c0f<\/span><\/span>
                                    \n#<\/span>define<\/span> MAX_PLOAD<\/span> 100<\/span> <\/span>\/\/ \u53d1\u9001\u6d88\u606f\u5185\u5b58\u7a7a\u95f4\u5927\u5c0f<\/span><\/span><\/p>\n

                                    \/\/ \u5b9a\u4e49\u63a5\u6536\u5185\u6838\u6d88\u606f\u7684\u7ed3\u6784\u4f53<\/span>
                                    \ntypedef<\/span> struct<\/span>
                                    \n{<\/span>
                                    \n struct<\/span> nlmsghdr<\/span> hdr;<\/span>
                                    \n char<\/span> msg[<\/span>RX_BUF_SIZE]<\/span>;<\/span>
                                    \n}<\/span>RX_KERNEL_MSG;<\/span><\/p>\n

                                    int<\/span> main<\/span>(<\/span>int<\/span> argc,<\/span> char<\/span>*<\/span> argv[<\/span>]<\/span>)<\/span>
                                    \n{<\/span>
                                    \n char<\/span> *<\/span>data =<\/span> "This message is from user's space"<\/span>;<\/span>
                                    \n \/\/ \u521d\u59cb\u5316\u53d8\u91cf<\/span>
                                    \n struct<\/span> sockaddr_nl<\/span> src_addr,<\/span> dest_addr;<\/span> \/\/ netlink \u5730\u5740\u7ed3\u6784\u4f53<\/span>
                                    \n int<\/span> skfd,<\/span> ret,<\/span> rxlen =<\/span> sizeof<\/span>(<\/span>struct<\/span> sockaddr_nl<\/span>)<\/span>;<\/span>
                                    \n struct<\/span> nlmsghdr<\/span> *<\/span>message;<\/span>
                                    \n RX_KERNEL_MSG info;<\/span>
                                    \n char<\/span> *<\/span>retval;<\/span><\/p>\n

                                    \/* 1. \u521b\u5efa NETLINK \u5957\u63a5\u5b57 *\/<\/span>
                                    \n skfd =<\/span> socket<\/span>(<\/span>PF_NETLINK,<\/span> SOCK_RAW,<\/span> NETLINK_TEST)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>skfd <<\/span> 0<\/span>)<\/span>{<\/span>
                                    \n printf<\/span>(<\/span>"can not create a netlink socket\\\\n"<\/span>)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n }<\/span><\/p>\n

                                    \/\/ \u521d\u59cb\u5316 netlink \u6e90\u5730\u5740<\/span>
                                    \n memset<\/span>(<\/span>&<\/span>src_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>src_addr)<\/span>)<\/span>;<\/span>
                                    \n src_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
                                    \n src_addr.<\/span>nl_pid =<\/span> getpid<\/span>(<\/span>)<\/span>;<\/span> \/\/ \u6e90\u7aef\u53e3\u4e3a\u5f53\u524d\u8fdb\u7a0b PID<\/span>
                                    \n src_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span> \/\/ \u4e0d\u52a0\u5165\u4efb\u4f55\u591a\u64ad\u7ec4<\/span><\/p>\n

                                    \/\/ \u7ed1\u5b9a\u5957\u63a5\u5b57\u5230\u6e90\u5730\u5740<\/span>
                                    \n if<\/span>(<\/span>bind<\/span>(<\/span>skfd,<\/span> (<\/span>struct<\/span> sockaddr<\/span> *<\/span>)<\/span>&<\/span>src_addr,<\/span> sizeof<\/span>(<\/span>src_addr)<\/span>)<\/span> !=<\/span> 0<\/span>)<\/span>{<\/span>
                                    \n printf<\/span>(<\/span>"bind() error\\\\n"<\/span>)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n }<\/span><\/p>\n

                                    \/\/ \u521d\u59cb\u5316 netlink \u76ee\u6807\u5730\u5740<\/span>
                                    \n memset<\/span>(<\/span>&<\/span>dest_addr,<\/span> 0<\/span>,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span>
                                    \n dest_addr.<\/span>nl_family =<\/span> AF_NETLINK;<\/span>
                                    \n dest_addr.<\/span>nl_pid =<\/span> 0<\/span>;<\/span> \/\/ \u76ee\u6807\u7aef\u53e3\u4e3a\u5185\u6838（PID = 0）<\/span>
                                    \n dest_addr.<\/span>nl_groups =<\/span> 0<\/span>;<\/span> \/\/ \u591a\u64ad\u7ec4\u63a9\u7801\u7f6e 0<\/span><\/p>\n

                                    \/* 2. \u6784\u9020\u901a\u4fe1\u6d88\u606f *\/<\/span>
                                    \n message =<\/span> (<\/span>struct<\/span> nlmsghdr<\/span> *<\/span>)<\/span>malloc<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>MAX_PLOAD)<\/span>)<\/span>;<\/span>
                                    \n memset<\/span>(<\/span>message,<\/span> '\\\\0'<\/span>,<\/span> sizeof<\/span>(<\/span>struct<\/span> nlmsghdr<\/span>)<\/span>)<\/span>;<\/span>
                                    \n message-><\/span>nlmsg_len =<\/span> NLMSG_SPACE<\/span>(<\/span>strlen<\/span>(<\/span>data)<\/span>)<\/span>;<\/span> \/\/ \u6d88\u606f\u603b\u957f\u5ea6（\u542b\u6d88\u606f\u5934）<\/span>
                                    \n message-><\/span>nlmsg_flags =<\/span> 0<\/span>;<\/span> \/\/ \u6d88\u606f\u6807\u5fd7\u4f4d\u7f6e 0<\/span>
                                    \n message-><\/span>nlmsg_type =<\/span> 0<\/span>;<\/span> \/\/ \u6d88\u606f\u7c7b\u578b\u7f6e 0<\/span>
                                    \n message-><\/span>nlmsg_seq =<\/span> 0<\/span>;<\/span> \/\/ \u6d88\u606f\u5e8f\u5217\u53f7\u7f6e 0<\/span>
                                    \n message-><\/span>nlmsg_pid =<\/span> src_addr.<\/span>nl_pid;<\/span> \/\/ \u6d88\u606f\u4e2d\u643a\u5e26\u6e90\u7aef\u53e3 PID<\/span><\/p>\n

                                    \/\/ \u62f7\u8d1d\u6709\u6548\u6570\u636e\u5230\u6d88\u606f\u4f53<\/span>
                                    \n retval =<\/span> memcpy<\/span>(<\/span>NLMSG_DATA<\/span>(<\/span>message)<\/span>,<\/span> data,<\/span> strlen<\/span>(<\/span>data)<\/span>)<\/span>;<\/span> <\/p>\n

                                    \/* 3. \u53d1\u9001\u6d88\u606f\u5230\u5185\u6838 *\/<\/span>
                                    \n ret =<\/span> sendto<\/span>(<\/span>skfd,<\/span> message,<\/span> message-><\/span>nlmsg_len,<\/span> 0<\/span>,<\/span>(<\/span>struct<\/span> sockaddr<\/span> *<\/span>)<\/span>&<\/span>dest_addr,<\/span> sizeof<\/span>(<\/span>dest_addr)<\/span>)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>!<\/span>ret)<\/span>{<\/span>
                                    \n perror<\/span>(<\/span>"send pid:"<\/span>)<\/span>;<\/span>
                                    \n exit<\/span>(<\/span>–<\/span>1<\/span>)<\/span>;<\/span>
                                    \n }<\/span><\/p>\n

                                    \/* 4. \u63a5\u6536\u5185\u6838\u8fd4\u56de\u7684\u54cd\u5e94\u6d88\u606f *\/<\/span>
                                    \n ret =<\/span> recvfrom<\/span>(<\/span>skfd,<\/span> &<\/span>info,<\/span> sizeof<\/span>(<\/span>RX_KERNEL_MSG)<\/span>,<\/span> 0<\/span>,<\/span> (<\/span>struct<\/span> sockaddr<\/span>*<\/span>)<\/span>&<\/span>dest_addr,<\/span> &<\/span>rxlen)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>!<\/span>ret)<\/span>{<\/span>
                                    \n perror<\/span>(<\/span>"recv form kerner:"<\/span>)<\/span>;<\/span>
                                    \n exit<\/span>(<\/span>–<\/span>1<\/span>)<\/span>;<\/span>
                                    \n }<\/span>
                                    \n printf<\/span>(<\/span>"User Receive ACK from kernel:%s\\\\r\\\\n"<\/span>,<\/span>(<\/span>char<\/span> *<\/span>)<\/span>info.<\/span>msg)<\/span>;<\/span><\/p>\n

                                    \/\/ \u91ca\u653e\u8d44\u6e90\u5e76\u5173\u95ed\u5957\u63a5\u5b57<\/span>
                                    \n close<\/span>(<\/span>skfd)<\/span>;<\/span>
                                    \n free<\/span>(<\/span>(<\/span>void<\/span> *<\/span>)<\/span>message)<\/span>;<\/span>
                                    \n return<\/span> 0<\/span>;<\/span>
                                    \n}<\/span><\/p>\n

                                    3.2 \u5185\u6838\u7a7a\u95f4 netlink \u4ee3\u7801<\/h4>\n

                                    3.2.1 netlink \u5185\u6838\u6001\u7f16\u7a0b\u57fa\u672c\u6b65\u9aa4<\/h5>\n

                                    \u5185\u6838\u4fa7 netlink \u7f16\u7a0b\u63a5\u53e3\u4e0e\u5e94\u7528\u5c42\u903b\u8f91\u76f8\u4f3c，\u6838\u5fc3\u6b65\u9aa4\u5982\u4e0b：<\/p>\n

                                    （1）\u521b\u5efa socket \u5e76\u6ce8\u518c\u56de\u8c03\u51fd\u6570<\/h6>\n

                                    \/\/ netlink \u5185\u6838\u914d\u7f6e\u7ed3\u6784\u4f53<\/span>
                                    \nstruct<\/span> netlink_kernel_cfg<\/span> {<\/span>
                                    \n unsigned<\/span> int<\/span> groups;<\/span>
                                    \n unsigned<\/span> int<\/span> flags;<\/span>
                                    \n void<\/span> (<\/span>*<\/span>input)<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>;<\/span> \/* \u6d88\u606f\u63a5\u6536\u56de\u8c03\u51fd\u6570 *\/<\/span>
                                    \n struct<\/span> mutex<\/span> *<\/span>cb_mutex;<\/span>
                                    \n int<\/span> (<\/span>*<\/span>bind)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> group)<\/span>;<\/span>
                                    \n void<\/span> (<\/span>*<\/span>unbind)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> group)<\/span>;<\/span>
                                    \n bool<\/span> (<\/span>*<\/span>compare)<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> struct<\/span> sock<\/span> *<\/span>sk)<\/span>;<\/span>
                                    \n}<\/span>;<\/span><\/p>\n

                                    \/* \u521b\u5efa\u5185\u6838 netlink socket，\u53c2\u6570 net \u901a\u5e38\u4f20\u5165 &init_net *\/<\/span>
                                    \nstatic<\/span> inline<\/span> struct<\/span> sock<\/span> *<\/span>netlink_kernel_create<\/span>(<\/span>struct<\/span> net<\/span> *<\/span>net,<\/span> int<\/span> unit,<\/span> struct<\/span> netlink_kernel_cfg<\/span> *<\/span>cfg)<\/span>
                                    \n\/* \u91ca\u653e\u5185\u6838 netlink socket *\/<\/span>
                                    \nvoid<\/span> netlink_kernel_release<\/span>(<\/span>struct<\/span> sock<\/span> *<\/span>sk)<\/span>;<\/span><\/p>\n

                                    （2）\u6784\u9020\u901a\u4fe1\u6d88\u606f<\/h6>\n

                                    \/\/ sk_buff \u662f\u5185\u6838\u4e2d netlink \u6d88\u606f\u7684\u8f7d\u4f53，\u4ee5\u4e0b\u4e3a\u5176\u5206\u914d\u3001\u5f15\u7528\u3001\u91ca\u653e\u63a5\u53e3<\/span>
                                    \nstatic<\/span> inline<\/span> struct<\/span> sk_buff<\/span> *<\/span>alloc_skb<\/span>(<\/span>unsigned<\/span> int<\/span> size,<\/span> gfp_t priority)<\/span>
                                    \nstatic<\/span> inline<\/span> struct<\/span> sk_buff<\/span> *<\/span>skb_get<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>
                                    \nvoid<\/span> kfree_skb<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>;<\/span><\/p>\n

                                    \/\/ \u6784\u9020 netlink \u6d88\u606f\u5934\u7684\u63a5\u53e3<\/span>
                                    \nstatic<\/span> inline<\/span> struct<\/span> nlmsghdr<\/span> *<\/span>nlmsg_put<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> u32 portid,<\/span> u32 seq,<\/span> int<\/span> type,<\/span> int<\/span> payload,<\/span> int<\/span> flags)<\/span><\/p>\n

                                    \u5178\u578b\u8c03\u7528\u793a\u4f8b：<\/p>\n

                                    \/\/ NLMSG_SPACE \u8ba1\u7b97\u5305\u542b\u6d88\u606f\u5934\u7684\u6d88\u606f\u603b\u957f\u5ea6<\/span>
                                    \nsize_t size =<\/span> max<\/span>(<\/span>NLMSG_SPACE<\/span>(<\/span>message_size)<\/span>,<\/span> (<\/span>size_t)<\/span>NLMSG_GOODSIZE)<\/span>;<\/span>
                                    \n\/\/ \u5206\u914d sk_buff \u5185\u5b58\u7a7a\u95f4<\/span>
                                    \nstruct<\/span> sk_buff<\/span> *<\/span> log_skb =<\/span> alloc_skb<\/span>(<\/span>size,<\/span> GFP_ATOMIC)<\/span>;<\/span>
                                    \n\/\/ \u6784\u9020\u6d88\u606f\u5934<\/span>
                                    \nstruct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> nlmsg_put<\/span>(<\/span>log_skb,<\/span> \/*pid*\/<\/span>0<\/span>,<\/span> \/*seq*\/<\/span>0<\/span>,<\/span> type,<\/span>
                                    \n message_size,<\/span> 0<\/span>)<\/span>;<\/span>
                                    \n\/\/ \u62f7\u8d1d\u6709\u6548\u6570\u636e\u5230\u6d88\u606f\u4f53<\/span>
                                    \nif<\/span>(<\/span>payload !=<\/span> NULL<\/span>)<\/span> {<\/span>
                                    \n memcpy<\/span>(<\/span>nlmsg_data<\/span>(<\/span>nlh)<\/span>,<\/span> payload,<\/span> size)<\/span>;<\/span>
                                    \n}<\/span><\/p>\n

                                    （3）\u53d1\u9001\/\u63a5\u6536\u6d88\u606f<\/h6>\n

                                    \u5185\u6838\u63d0\u4f9b\u5355\u64ad\u3001\u591a\u64ad\u4e24\u7c7b\u6d88\u606f\u53d1\u9001\u63a5\u53e3，\u53ef\u6839\u636e\u4e1a\u52a1\u573a\u666f\u9009\u62e9：<\/p>\n

                                    int<\/span> netlink_unicast<\/span>(<\/span>struct<\/span> sock<\/span> *<\/span>ssk,<\/span> struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> __u32 portid,<\/span> int<\/span> nonblock)<\/span>;<\/span>
                                    \nint<\/span> netlink_broadcast<\/span>(<\/span>struct<\/span> sock<\/span> *<\/span>ssk,<\/span> struct<\/span> sk_buff<\/span> *<\/span>skb,<\/span> __u32 portid,<\/span> __u32 group,<\/span> gfp_t allocation)<\/span>;<\/span><\/p>\n

                                    3.2.2 netlink \u5185\u6838\u6001\u6a21\u5757\u5b8c\u6574\u4ee3\u7801<\/h5>\n

                                    #<\/span>include<\/span> <linux\/kernel.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <linux\/module.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <linux\/types.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <linux\/sched.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <net\/sock.h><\/span><\/span>
                                    \n#<\/span>include<\/span> <linux\/netlink.h><\/span><\/span><\/p>\n

                                    #<\/span>define<\/span> NETLINK_TEST<\/span> 17<\/span> <\/span>\/\/ \u4e0e\u7528\u6237\u6001\u4e00\u81f4\u7684\u81ea\u5b9a\u4e49\u534f\u8bae\u7c7b\u578b<\/span><\/span><\/p>\n

                                    \/\/ \u5b58\u50a8\u7528\u6237\u8fdb\u7a0b PID \u7684\u7ed3\u6784\u4f53<\/span>
                                    \nstruct<\/span> {<\/span>
                                    \n __u32 pid;<\/span>
                                    \n}<\/span>user_process;<\/span><\/p>\n

                                    static<\/span> struct<\/span> sock<\/span> *<\/span>netlinkfd =<\/span> NULL<\/span>;<\/span> \/\/ netlink socket \u6307\u9488<\/span><\/p>\n

                                    \/* \u5411\u7528\u6237\u7a7a\u95f4\u53d1\u9001\u6d88\u606f\u7684\u51fd\u6570 *\/<\/span>
                                    \nint<\/span> send_to_user<\/span>(<\/span>int<\/span> _pid,<\/span> char<\/span> *<\/span>pbuf,<\/span> uint16_t<\/span> len)<\/span>
                                    \n{<\/span>
                                    \n struct<\/span> sk_buff<\/span> *<\/span>nl_skb;<\/span>
                                    \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh;<\/span>
                                    \n int<\/span> ret;<\/span><\/p>\n

                                    \/* \u5206\u914d sk_buff \u5185\u5b58\u7a7a\u95f4 *\/<\/span>
                                    \n nl_skb =<\/span> nlmsg_new<\/span>(<\/span>len,<\/span> GFP_ATOMIC)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>!<\/span>nl_skb)<\/span>
                                    \n {<\/span>
                                    \n printk<\/span>(<\/span>"netlink alloc failure\\\\n"<\/span>)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n }<\/span><\/p>\n

                                    \/* \u6784\u9020 netlink \u6d88\u606f\u5934 *\/<\/span>
                                    \n nlh =<\/span> nlmsg_put<\/span>(<\/span>nl_skb,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> NETLINK_TEST,<\/span> len,<\/span> 0<\/span>)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>nlh ==<\/span> NULL<\/span>)<\/span>
                                    \n {<\/span>
                                    \n printk<\/span>(<\/span>"nlmsg_put failure \\\\n"<\/span>)<\/span>;<\/span>
                                    \n nlmsg_free<\/span>(<\/span>nl_skb)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n }<\/span><\/p>\n

                                    \/* \u62f7\u8d1d\u6570\u636e\u5230\u6d88\u606f\u4f53 *\/<\/span>
                                    \n memcpy<\/span>(<\/span>nlmsg_data<\/span>(<\/span>nlh)<\/span>,<\/span> pbuf,<\/span> len)<\/span>;<\/span><\/p>\n

                                    \/\/ \u53d1\u9001\u5355\u64ad\u6d88\u606f\u5230\u7528\u6237\u8fdb\u7a0b<\/span>
                                    \n ret =<\/span> netlink_unicast<\/span>(<\/span>netlinkfd,<\/span> nl_skb,<\/span> _pid,<\/span> MSG_DONTWAIT)<\/span>;<\/span>
                                    \n return<\/span> ret;<\/span>
                                    \n}<\/span><\/p>\n

                                    \/* \u6d88\u606f\u63a5\u6536\u56de\u8c03\u51fd\u6570 *\/<\/span>
                                    \nstatic<\/span> void<\/span> netlink_rcv_msg<\/span>(<\/span>struct<\/span> sk_buff<\/span> *<\/span>skb)<\/span>
                                    \n{<\/span>
                                    \n struct<\/span> nlmsghdr<\/span> *<\/span>nlh =<\/span> NULL<\/span>;<\/span>
                                    \n char<\/span> *<\/span>data =<\/span> NULL<\/span>;<\/span>
                                    \n char<\/span> *<\/span>kmsg =<\/span> "hello users!!!"<\/span>;<\/span><\/p>\n

                                    \/\/ \u83b7\u53d6\u6d88\u606f\u5934<\/span>
                                    \n nlh =<\/span> nlmsg_hdr<\/span>(<\/span>skb)<\/span>;<\/span>
                                    \n \/\/ \u6821\u9a8c\u6d88\u606f\u957f\u5ea6\u5408\u6cd5\u6027<\/span>
                                    \n if<\/span>(<\/span>skb-><\/span>len >=<\/span> NLMSG_SPACE<\/span>(<\/span>0<\/span>)<\/span>)<\/span>
                                    \n {<\/span>
                                    \n data =<\/span> NLMSG_DATA<\/span>(<\/span>nlh)<\/span>;<\/span> \/\/ \u63d0\u53d6\u6d88\u606f\u4f53\u6570\u636e<\/span>
                                    \n if<\/span> (<\/span>data)<\/span>
                                    \n {<\/span>
                                    \n \/\/ \u8bb0\u5f55\u53d1\u9001\u7aef\u7528\u6237\u8fdb\u7a0b PID<\/span>
                                    \n user_process.<\/span>pid =<\/span> nlh-><\/span>nlmsg_pid;<\/span>
                                    \n printk<\/span>(<\/span>"kernel recv from user pid %d: %s\\\\n"<\/span>,<\/span> user_process.<\/span>pid,<\/span> data)<\/span>;<\/span>
                                    \n \/\/ \u5411\u7528\u6237\u8fdb\u7a0b\u53d1\u9001\u54cd\u5e94\u6d88\u606f<\/span>
                                    \n send_to_user<\/span>(<\/span>user_process.<\/span>pid,<\/span> kmsg,<\/span> strlen<\/span>(<\/span>kmsg)<\/span>)<\/span>;<\/span>
                                    \n }<\/span>
                                    \n }<\/span> else<\/span> {<\/span>
                                    \n printk<\/span>(<\/span>"%s: error skb, length:%d\\\\n"<\/span>,<\/span> __func__<\/span>,<\/span> skb-><\/span>len)<\/span>;<\/span>
                                    \n }<\/span>
                                    \n}<\/span><\/p>\n

                                    \/\/ \u5b9a\u4e49 netlink \u5185\u6838\u914d\u7f6e<\/span>
                                    \nstruct<\/span> netlink_kernel_cfg<\/span> cfg =<\/span> {<\/span>
                                    \n .<\/span>input =<\/span> netlink_rcv_msg,<\/span> \/* \u6ce8\u518c\u6d88\u606f\u63a5\u6536\u56de\u8c03\u51fd\u6570 *\/<\/span>
                                    \n .<\/span>groups =<\/span> 0<\/span>,<\/span> \/\/ \u591a\u64ad\u7ec4\u6570\u91cf\u7f6e 0<\/span>
                                    \n .<\/span>flags =<\/span> 0<\/span>,<\/span>
                                    \n .<\/span>cb_mutex =<\/span> NULL<\/span>,<\/span>
                                    \n .<\/span>bind =<\/span> NULL<\/span>,<\/span>
                                    \n .<\/span>compare =<\/span> NULL<\/span>,<\/span>
                                    \n}<\/span>;<\/span><\/p>\n

                                    \/\/ \u6a21\u5757\u521d\u59cb\u5316\u51fd\u6570<\/span>
                                    \nint<\/span> __init test_netlink_init<\/span>(<\/span>void<\/span>)<\/span>
                                    \n{<\/span>
                                    \n \/* \u521b\u5efa netlink socket *\/<\/span>
                                    \n netlinkfd =<\/span> (<\/span>struct<\/span> sock<\/span> *<\/span>)<\/span>netlink_kernel_create<\/span>(<\/span>&<\/span>init_net,<\/span> NETLINK_TEST,<\/span> &<\/span>cfg)<\/span>;<\/span>
                                    \n if<\/span>(<\/span>netlinkfd ==<\/span> NULL<\/span>)<\/span>{<\/span>
                                    \n printk<\/span>(<\/span>KERN_ERR "can not create a netlink socket\\\\n"<\/span>)<\/span>;<\/span>
                                    \n return<\/span> –<\/span>1<\/span>;<\/span>
                                    \n }<\/span>
                                    \n return<\/span> 0<\/span>;<\/span>
                                    \n}<\/span><\/p>\n

                                    \/\/ \u6a21\u5757\u9000\u51fa\u51fd\u6570<\/span>
                                    \nvoid<\/span> __exit test_netlink_exit<\/span>(<\/span>void<\/span>)<\/span>
                                    \n{<\/span>
                                    \n if<\/span> (<\/span>netlinkfd)<\/span>{<\/span>
                                    \n netlink_kernel_release<\/span>(<\/span>netlinkfd)<\/span>;<\/span> \/* \u91ca\u653e netlink socket *\/<\/span>
                                    \n netlinkfd =<\/span> NULL<\/span>;<\/span>
                                    \n }<\/span>
                                    \n printk<\/span>(<\/span>KERN_DEBUG "test_netlink_exit!!\\\\n"<\/span>)<\/span>;<\/span>
                                    \n}<\/span><\/p>\n

                                    module_init<\/span>(<\/span>test_netlink_init)<\/span>;<\/span>
                                    \nmodule_exit<\/span>(<\/span>test_netlink_exit)<\/span>;<\/span>
                                    \nMODULE_LICENSE<\/span>(<\/span>"GPL"<\/span>)<\/span>;<\/span>
                                    \nMODULE_AUTHOR<\/span>(<\/span>"donga"<\/span>)<\/span>;<\/span><\/p>\n

                                    3.3 \u6d4b\u8bd5\u7ed3\u679c<\/h4>\n

                                    \u6d4b\u8bd5\u4ee3\u7801\u4e0b\u8f7d\u94fe\u63a5：https:\/\/download.csdn.net\/download\/hinewcc\/89590914<\/p>\n

                                    \u5c06\u5185\u6838\u6001\u4ee3\u7801\u7f16\u8bd1\u4e3a ko \u6a21\u5757，\u7528\u6237\u6001\u4ee3\u7801\u7f16\u8bd1\u4e3a\u53ef\u6267\u884c\u7a0b\u5e8f；\u901a\u8fc7 insmod \u547d\u4ee4\u52a0\u8f7d ko \u6a21\u5757\u540e\u8fd0\u884c\u7528\u6237\u6001\u7a0b\u5e8f：<\/p>\n

                                    $ insmod netlink_test.ko # \u52a0\u8f7d\u5185\u6838\u6a21\u5757<\/span><\/p>\n

                                    $ .\/netlink_app # \u8fd0\u884c\u7528\u6237\u6001\u5e94\u7528\u7a0b\u5e8f<\/span><\/p>\n

                                    \"img\"<\/p>\n

                                    \u5185\u6838\u6001\u53ef\u63a5\u6536\u7528\u6237\u6001\u53d1\u9001\u7684\u6570\u636e，\u5e76\u5411\u7528\u6237\u7a7a\u95f4\u8fd4\u56de \u201chello users!!!\u201d \u54cd\u5e94\u6d88\u606f\u3002<\/p>\n

                                    3.4 netlink \u72b6\u6001\u67e5\u770b\u547d\u4ee4<\/h4>\n

                                    \u901a\u8fc7\u5982\u4e0b\u547d\u4ee4\u53ef\u67e5\u770b\u7cfb\u7edf\u4e2d netlink \u63a5\u53e3\u7684 ID \u53ca\u72b6\u6001：<\/p>\n

                                    $ cat<\/span> \/proc\/net\/netlink<\/p>\n

                                    \"img\"<\/p>\n

                                    \n

                                    \u603b\u7ed3<\/h4>\n
                                  • netlink \u662f Linux \u5185\u6838\u4e0e\u7528\u6237\u7a7a\u95f4\u7684\u53cc\u5411\u901a\u4fe1\u673a\u5236，\u76f8\u6bd4 proc\u3001ioctl \u5177\u5907\u5168\u53cc\u5de5\u3001\u5f02\u6b65\u3001\u591a\u64ad\u7b49\u7279\u6027，\u662f\u7f51\u7edc\u7c7b\u5185\u6838\u4ea4\u4e92\u7684\u4e3b\u6d41\u65b9\u5f0f；<\/li>\n
                                  • netlink \u6d88\u606f\u7531 16 \u5b57\u8282\u56fa\u5b9a\u957f\u5ea6\u7684\u6d88\u606f\u5934（nlmsghdr）\u548c\u53ef\u53d8\u957f\u5ea6\u7684\u6d88\u606f\u4f53\u7ec4\u6210，\u5bfb\u5740\u65b9\u5f0f\u4e3a\u300c\u534f\u8bae\u7c7b\u578b + \u8fdb\u7a0b PID\u300d，\u533a\u522b\u4e8e\u4f20\u7edf\u7f51\u7edc\u7f16\u7a0b\u7684\u300cIP \u5730\u5740 + \u7aef\u53e3\u53f7\u300d；<\/li>\n
                                  • \u5185\u6838\u6001\u9700\u901a\u8fc7 netlink_kernel_create \u521b\u5efa socket \u5e76\u6ce8\u518c\u56de\u8c03\u51fd\u6570，\u7528\u6237\u6001\u53ef\u76f4\u63a5\u4f7f\u7528\u6807\u51c6 socket API，\u6838\u5fc3\u4ea4\u4e92\u63a5\u53e3\u5305\u62ec sendto\/recvfrom（\u5355\u64ad）\u3001netlink_broadcast（\u591a\u64ad）\u7b49\u3002<\/li>\n
                                    \n

                                    via:<\/h2>\n
                                      \n
                                    • \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u901a\u8baf\u4e4b\u3010Netlink \u4e0a\u3011-wjlkoorey258-ChinaUnix\u535a\u5ba2 http:\/\/blog.chinaunix.net\/uid-23069658-id-3400761.html<\/li>\n
                                    • \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u901a\u8baf\u4e4b\u3010Netlink \u4e2d\u3011-wjlkoorey258-ChinaUnix\u535a\u5ba2 http:\/\/blog.chinaunix.net\/uid-23069658-id-3405954.html<\/li>\n
                                    • \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u901a\u8baf\u4e4b\u3010Netlink \u4e0b\u3011-wjlkoorey258-ChinaUnix\u535a\u5ba2 http:\/\/blog.chinaunix.net\/uid-23069658-id-3409786.html<\/li>\n
                                    • linux \u5185\u6838\u4e0e\u7528\u6237\u7a7a\u95f4\u901a\u4fe1\u4e4bnetlink\u4f7f\u7528\u65b9\u6cd5-CSDN\u535a\u5ba2 https:\/\/blog.csdn.net\/HAOMCU\/article\/details\/7371835<\/li>\n
                                    • Linux\u5185\u6838netlink\u673a\u5236 – \u7528\u6237\u7a7a\u95f4\u548c\u5185\u6838\u7a7a\u95f4\u6570\u636e\u4f20\u8f93-CSDN\u535a\u5ba2 https:\/\/blog.csdn.net\/hinewcc\/article\/details\/139156381<\/li>\n
                                    • linux netlink\u901a\u4fe1\u673a\u5236 – zhangwju – \u535a\u5ba2\u56ed 2017 https:\/\/www.cnblogs.com\/wenqiang\/p\/6306727.html<\/li>\n
                                    • Netlink \u624b\u518c \u2014 Linux \u5185\u6838\u6587\u6863 – Linux \u5185\u6838 https:\/\/linuxkernel.org.cn\/doc\/html\/latest\/userspace-api\/netlink\/index.html<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                                      \u6ce8：\u672c\u6587\u4e3a \u201cLinux Netlink \u901a\u4fe1\u673a\u5236\u201d \u76f8\u5173\u5408\u8f91\u3002 \u7565\u4f5c\u91cd\u6392，\u672a\u6574\u7406\u53bb\u91cd\u3002 \u5982\u6709\u5185\u5bb9\u5f02\u5e38，\u8bf7\u770b\u539f\u6587\u3002 \u7528\u6237\u7a7a\u95f4\u4e0e\u5185\u6838\u7a7a\u95f4\u901a\u4fe1\u2014\u2014Netlink（\u4e0a）
                                      \nwjlkoorey258 2012-11-07 22:00:24
                                      \n\u5f15\u8a00
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