\/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/
\n #content_views .toc,
\n \/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/
\n #content_views.markdown_views > p:empty:has(+ .toc),
\n #content_views.markdown_views > .toc + p:empty,
\n \/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/
\n #content_views.htmledit_views #main-toc,
\n #content_views.htmledit_views #hr-toc,
\n #content_views.htmledit_views p[id*=\\”-toc\\”] {
\n display: none !important;
\n }
\n \/* \u76ee\u5f55\u53bb\u6389\u540e\uff0c\u7d27\u8ddf\u7684\u9996\u4e2a\u6807\u9898\u4e0d\u518d\u591a\u51fa\u4e00\u5757\u4e0a\u8fb9\u8ddd *\/
\n #content_views.markdown_views > .toc + h1,
\n #content_views.markdown_views > .toc + h2,
\n #content_views.markdown_views > .toc + h3,
\n #content_views.markdown_views > .toc + h4,
\n #content_views.markdown_views > .toc + p:empty + h1,
\n #content_views.markdown_views > .toc + p:empty + h2,
\n #content_views.markdown_views > .toc + p:empty + h3,
\n #content_views.markdown_views > .toc + p:empty + h4 {
\n margin-top: 0 !important;
\n }<\/p>\n
\u672c\u6587\u4eceUDP Socket\u7684\u57fa\u7840\u51fa\u53d1，\u4e00\u8def\u5f80\u4e0b\u8d70\u3002<\/p>\n
\u5148\u628asocket\u3001sockaddr_in\u8fd9\u4e9b\u6700\u57fa\u7840\u7684\u6982\u5ff5\u8bb2\u6e05\u695a，\u518d\u628a\u5b57\u8282\u5e8f\u3001recvfrom\/sendto\u8fd9\u5bf9\u6536\u53d1\u642d\u6863\u9010\u4e00\u62c6\u5f00\u3002\u63a5\u7740\u770b\u670d\u52a1\u7aef\u600e\u4e48bind，\u5ba2\u6237\u7aef\u4e3a\u4ec0\u4e48\u662f\u9690\u5f0fbind，INADDR_ANY\u53c8\u5230\u5e95\u610f\u5473\u7740\u4ec0\u4e48\u3002\u6700\u540e，\u628aIP\u5730\u5740\u8f6c\u6362\u548c\u7ebf\u7a0b\u5b89\u5168\u7684API\u4e00\u5e76\u6536\u5c3e\u3002<\/p>\n
\u76ee\u5f55<\/p>\n
\u4e00\u3001UDP\u5957\u63a5\u5b57\u7f16\u7a0b\u57fa\u7840：\u4ece\u521b\u5efa\u5957\u63a5\u5b57\u5230\u63a5\u6536\u6570\u636e<\/p>\n
1.1 Socket\u7f16\u7a0b\u57fa\u7840\u4e0e\u5e38\u7528\u5934\u6587\u4ef6<\/p>\n
1.2 \u521b\u5efa\u5957\u63a5\u5b57：socket\u51fd\u6570\u8be6\u89e3<\/p>\n
1.2.1 \u53c2\u6570\u89e3\u6790\u4e0e\u5e38\u7528\u5e38\u91cf<\/p>\n
1.2.2 \u8fd4\u56de\u503c\u4e0eLinux\u201c\u4e00\u5207\u7686\u6587\u4ef6\u201d\u7684\u8bbe\u8ba1\u601d\u60f3<\/p>\n
1.3 IPv4\u5730\u5740\u7ed3\u6784：sockaddr_in\u8be6\u89e3<\/p>\n
1.3.1 sockaddr_in\u7684\u7ed3\u6784\u6210\u5458\u4e0e\u542b\u4e49<\/p>\n
1.4 IP\u5730\u5740\u8f6c\u6362\u4e0e\u5b57\u8282\u5e8f\u5904\u7406<\/p>\n
1.4.1 \u70b9\u5206\u5341\u8fdb\u5236\u5730\u5740\u4e0e\u7f51\u7edc\u5b57\u8282\u5e8f\u7684\u8f6c\u6362<\/p>\n
1.5 \u63a5\u6536\u6570\u636e：recvfrom\u51fd\u6570\u8be6\u89e3<\/p>\n
1.5.1 \u53c2\u6570\u542b\u4e49\u4e0e\u8fd4\u56de\u503c<\/p>\n
\u4e8c\u3001UDP\u5ba2\u6237\u7aef\u4e0e\u670d\u52a1\u5668：\u4ece\u521d\u59cb\u5316\u5230\u6570\u636e\u6536\u53d1<\/p>\n
2.1 \u670d\u52a1\u5668\u521d\u59cb\u5316：\u5730\u5740\u914d\u7f6e\u4e0e\u7aef\u53e3\u7ed1\u5b9a<\/p>\n
2.1.1 \u7ed3\u6784\u4f53\u6e05\u96f6：bzero\u4e0eexplicit_bzero<\/p>\n
2.1.2 \u586b\u5145sockaddr_in\u4e0e\u7f51\u7edc\u5b57\u8282\u5e8f\u8f6c\u6362<\/p>\n
2.1.3 \u7ed1\u5b9a\u672c\u5730\u5730\u5740：bind\u7cfb\u7edf\u8c03\u7528<\/p>\n
2.2 UDP\u6570\u636e\u6536\u53d1\u673a\u5236：\u4ece\u63a5\u6536\u5230\u54cd\u5e94<\/p>\n
2.2.1 \u6570\u636e\u63a5\u6536：recvfrom\u4e0e\u963b\u585eI\/O<\/p>\n
2.2.2 \u6570\u636e\u53d1\u9001：sendto\u51fd\u6570<\/p>\n
2.3 \u5ba2\u6237\u7aef\u901a\u4fe1：\u670d\u52a1\u5668\u5730\u5740\u4e0e\u7aef\u53e3\u5206\u914d<\/p>\n
2.3.1 \u670d\u52a1\u5668\u5730\u5740\u7684\u786c\u7f16\u7801\u4e0e\u914d\u7f6e\u6587\u4ef6\u7ba1\u7406<\/p>\n
2.3.2 \u5ba2\u6237\u7aef\u7684\u9690\u5f0f\u7ed1\u5b9a：\u7aef\u53e3\u7531\u8c01\u5206\u914d<\/p>\n
\u4e09\u3001\u6df1\u5165\u7406\u89e3bind：\u5ba2\u6237\u7aef\u7b56\u7565\u4e0e\u670d\u52a1\u7aef\u9700\u6c42<\/p>\n
3.1 UDP\u5ba2\u6237\u7aef\u662f\u5426\u9700\u8981\u663e\u5f0f\u8c03\u7528bind<\/p>\n
3.2 \u4e3a\u4ec0\u4e48UDP\u670d\u52a1\u7aef\u901a\u5e38\u9700\u8981\u663e\u5f0f\u7ed1\u5b9a\u7aef\u53e3<\/p>\n
\u56db\u3001UDP\u670d\u52a1\u5668\u8fdb\u9636：\u5730\u5740\u7ed1\u5b9a\u3001\u4e1a\u52a1\u89e3\u8026\u4e0e\u8f6c\u6362\u63a5\u53e3<\/p>\n
4.1 \u670d\u52a1\u5668\u5730\u5740\u7ed1\u5b9a\u4e2d\u7684\u5e38\u89c1\u95ee\u9898\u4e0eINADDR_ANY\u539f\u7406<\/p>\n
4.1.1 \u5e38\u89c1\u7684\u5730\u5740\u7ed1\u5b9a\u8bef\u533a<\/p>\n
4.1.2 \u4f7f\u7528INADDR_ANY：\u76d1\u542c\u672c\u673a\u7684\u591a\u4e2aIPv4\u5730\u5740<\/p>\n
4.2 \u8f6f\u4ef6\u5206\u5c42\u8bbe\u8ba1：\u5b9e\u73b0UDP\u901a\u4fe1\u4e0e\u4e1a\u52a1\u903b\u8f91\u89e3\u8026<\/p>\n
4.2.1 \u4f7f\u7528\u56de\u8c03\u51fd\u6570\u5904\u7406\u4e1a\u52a1\u903b\u8f91<\/p>\n
4.2.2 \u56de\u8c03\u51fd\u6570\u6a21\u5f0f\u5b9e\u73b0<\/p>\n
4.3 IP\u5730\u5740\u8f6c\u6362\u51fd\u6570\u7684\u6f14\u8fdb\u4e0e\u7ebf\u7a0b\u5b89\u5168\u6027<\/p>\n
4.3.1 \u65e7\u7248\u5730\u5740\u8f6c\u6362API\u53ca\u5176\u5c40\u9650<\/p>\n
4.3.2 \u73b0\u4ee3\u5730\u5740\u8f6c\u6362API：inet_pton\u4e0einet_ntop<\/p>\n
\u4e94\u3001\u5b8c\u6574\u6e90\u7801\u4e0e\u8fd0\u884c\u6d4b\u8bd5<\/p>\n
5.1 InetAddr.hpp：IP\u5730\u5740\u5c01\u88c5\u7c7b<\/p>\n
5.2 UdpServer.hpp：UDP\u670d\u52a1\u5668\u7c7b<\/p>\n
5.3 UdpServer.cc：\u670d\u52a1\u7aef\u4e3b\u7a0b\u5e8f<\/p>\n
5.4 UdpClient.cc：\u5ba2\u6237\u7aef\u4e3b\u7a0b\u5e8f<\/p>\n
5.5 Makefile：\u9879\u76ee\u7f16\u8bd1\u89c4\u5219<\/p>\n
5.6 \u7f16\u8bd1\u8fd0\u884c\u4e0e\u901a\u4fe1\u6d4b\u8bd5<\/p>\n
\u7f51\u7edc\u7f16\u7a0b\u7684\u6838\u5fc3，\u5c31\u662f\u501f\u52a9\u64cd\u4f5c\u7cfb\u7edf\u63d0\u4f9b\u7684\u5957\u63a5\u5b57（Socket）\u63a5\u53e3，\u8ba9\u8fdb\u7a0b\u4e4b\u95f4\u3001\u4e3b\u673a\u4e4b\u95f4\u80fd\u591f\u4ea4\u6362\u6570\u636e\u3002\u4f20\u8f93\u5c42\u534f\u8bae\u91cc，UDP（\u7528\u6237\u6570\u636e\u62a5\u534f\u8bae）\u662f\u4e2a\u65e0\u8fde\u63a5\u3001\u4e0d\u53ef\u9760\u3001\u9762\u5411\u6570\u636e\u62a5\u7684\u534f\u8bae\u3002<\/p>\n
\u5728Linux\u7f51\u7edc\u7f16\u7a0b\u4e2d，\u641e\u5957\u63a5\u5b57\u5f00\u53d1\u901a\u5e38\u7ed5\u4e0d\u5f00\u8fd9\u56db\u4e2a\u57fa\u7840\u5934\u6587\u4ef6：<\/p>\n
#include <sys\/types.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h> <\/p>\n
\u7f51\u7edc\u901a\u4fe1\u7684\u7b2c\u4e00\u6b65，\u662f\u521b\u5efa\u5957\u63a5\u5b57\u3002Linux\u91cc\u9760socket()\u8fd9\u4e2a\u7cfb\u7edf\u8c03\u7528\u6765\u641e\u5b9a：<\/p>\n
int socket(int domain, int type, int protocol); <\/p>\n
domain（\u534f\u8bae\u65cf\/\u5730\u5740\u65cf）：\u6307\u5b9a\u901a\u4fe1\u7684\u9886\u57df，\u8bf4\u767d\u4e86\u5c31\u662f\u51b3\u5b9a\u8fd9\u6b21\u662f\u672c\u5730\u8fdb\u7a0b\u95f4\u901a\u4fe1，\u8fd8\u662f\u8d70\u7f51\u7edc\u901a\u4fe1\u3002<\/p>\n
type（\u5957\u63a5\u5b57\u7c7b\u578b）：\u6307\u5b9a\u901a\u4fe1\u7684\u6570\u636e\u4f20\u8f93\u670d\u52a1\u7c7b\u578b\u3002<\/p>\n
protocol（\u534f\u8bae\u7c7b\u578b）：\u901a\u5e38\u586b0\u3002\u7cfb\u7edf\u4f1a\u6839\u636edomain\u548ctype\u81ea\u52a8\u63a8\u5bfc\u51fa\u9ed8\u8ba4\u534f\u8bae，\u6bd4\u5982AF_INET\u914dSOCK_DGRAM，\u9ed8\u8ba4\u5c31\u662fUDP\u534f\u8bae\u3002<\/p>\n
\u5957\u63a5\u5b57\u5728Linux\u91cc\u88ab\u62bd\u8c61\u6210\u4e00\u4e2a\u6587\u4ef6\u63cf\u8ff0\u7b26，\u8fd9\u6070\u6070\u4f53\u73b0\u4e86\u201c\u4e00\u5207\u7686\u6587\u4ef6\u201d\u7684\u8bbe\u8ba1\u54f2\u5b66\u3002\u7f51\u7edc\u8bbe\u5907\u7684\u8bfb\u5199，\u548c\u666e\u901a\u6587\u4ef6\u7684\u8bfb\u5199，\u5728\u5185\u6838\u5c42\u9762\u6709\u7740\u9ad8\u5ea6\u7edf\u4e00\u7684\u64cd\u4f5c\u63a5\u53e3\u3002<\/p>\n
\u6253\u54ea\u513f\u8bfb\u3001\u5f80\u54ea\u513f\u5199，\u5e95\u5c42\u90fd\u662f\u540c\u4e00\u5957\u4e1c\u897f\u3002\u5957\u63a5\u5b57\u62ab\u7740\u7f51\u7edc\u7684\u5916\u8863，\u9aa8\u5b50\u91cc\u8fd8\u662f\u4e2a\u6587\u4ef6\u3002<\/p>\n
\u4e3a\u4e86\u517c\u5bb9\u4e94\u82b1\u516b\u95e8\u7684\u534f\u8bae\u65cf\u5730\u5740\u683c\u5f0f，Linux\u8bbe\u8ba1\u4e86\u4e00\u4e2a\u901a\u7528\u7ed3\u6784\u4f53struct sockaddr\u3002\u4f46\u771f\u5230\u4e86IPv4\u7f51\u7edc\u901a\u4fe1\u7684\u5b9e\u6218\u91cc，\u7528\u7684\u5374\u662f\u4e13\u95e8\u7684struct sockaddr_in\u3002<\/p>\n
struct sockaddr_in\u7684\u5185\u90e8\u7ec4\u7ec7，\u957f\u8fd9\u6837：<\/p>\n
struct sockaddr_in {
\n __SOCKADDR_COMMON (sin_); \/* 16 \u4f4d\u5730\u5740\u7c7b\u578b \/ \u534f\u8bae\u5bb6\u65cf，\u5982 AF_INET *\/
\n in_port_t sin_port; \/* 16 \u4f4d\u7aef\u53e3\u53f7（\u7f51\u7edc\u5b57\u8282\u5e8f） *\/
\n struct in_addr sin_addr; \/* 32 \u4f4d IP \u5730\u5740（\u7f51\u7edc\u5b57\u8282\u5e8f） *\/
\n unsigned char sin_zero[8]; \/* \u586b\u5145\u9879，\u7528\u4e8e\u4e0e struct sockaddr \u4fdd\u6301\u5927\u5c0f\u4e00\u81f4 *\/
\n}; <\/p>\n
\u7ed3\u6784\u4f53\u6210\u5458\u9010\u4e2a\u62c6：<\/p>\n
\u5730\u5740\u7c7b\u578b（sin_family）：\u901a\u8fc7\u5185\u6838\u5b8f__SOCKADDR_COMMON(sin_)\u5c55\u5f00\u540e，\u5c31\u662fsa_family_t sin_family，\u7528\u6765\u6307\u5b9a\u534f\u8bae\u65cf，\u6bd4\u5982AF_INET\u3002\u90a3\u4e2a##\u662fC\u8bed\u8a00\u9884\u5904\u7406\u5668\u7684\u8fd0\u7b97\u7b26，\u4e13\u95e8\u8d1f\u8d23\u628a\u7b26\u53f7\u62fc\u63a5\u5408\u5e76\u3002<\/p>\n
\u7aef\u53e3\u53f7（sin_port）：16\u4f4d\u65e0\u7b26\u53f7\u6574\u6570，\u8868\u793a\u901a\u4fe1\u8fdb\u7a0b\u7684\u7aef\u53e3\u53f7\u3002\u6ce8\u610f，\u5b83\u5f97\u662f\u7f51\u7edc\u5b57\u8282\u5e8f\u3002<\/p>\n
IP \u5730\u5740（sin_addr）：\u5185\u90e8\u88c5\u7740\u4e00\u4e2a32\u4f4d\u65e0\u7b26\u53f7\u6574\u6570，\u8868\u793aIPv4\u5730\u5740\u3002\u540c\u6837，\u7f51\u7edc\u5b57\u8282\u5e8f\u3002<\/p>\n
\u586b\u5145\u7269（sin_zero）：8\u4e2a\u5b57\u8282\u7684\u586b\u5145\u3002\u4e3a\u4ec0\u4e48\u8981\u5b83？\u4e3a\u4e86\u8ba9\u6574\u4e2astruct sockaddr_in\u7684\u5927\u5c0f，\u8ddf\u901a\u7528\u7684struct sockaddr\u4e25\u4e1d\u5408\u7f1d\u5730\u5bf9\u4e0a，sockaddr\u90a3\u8fb9\u662f14\u5b57\u8282\u5730\u5740\u6570\u636e\u52a02\u5b57\u8282\u7c7b\u578b，\u6b63\u597d16\u5b57\u8282\u3002\u5927\u5c0f\u4e00\u81f4，\u4e24\u8005\u624d\u80fd\u5b89\u5168\u5730\u4e92\u76f8\u5f3a\u8f6c\u3002<\/p>\n
\u5728\u8ba1\u7b97\u673a\u5185\u90e8\u548c\u7f51\u7edc\u4f20\u8f93\u91cc，IP\u5730\u5740\u7684\u8868\u793a\u5f62\u5f0f\u5b8c\u5168\u662f\u4e24\u7801\u4e8b\u3002\u7528\u6237\u4e60\u60ef\u70b9\u5206\u5341\u8fdb\u5236\u5b57\u7b26\u4e32，\u6bd4\u5982"192.168.1.1"；\u53ef\u7f51\u7edc\u5e95\u5c42\u4f20\u8f93\u548c\u7ed3\u6784\u4f53\u5b58\u50a8，\u8981\u7684\u662f32\u4f4d\u65e0\u7b26\u53f7\u6574\u6570（uint32_t），\u800c\u4e14\u5fc5\u987b\u5b88\u7f51\u7edc\u5b57\u8282\u5e8f\u7684\u89c4\u77e9，\u4e5f\u5c31\u662f\u5927\u7aef\u3002<\/p>\n
IP\u5b57\u7b26\u4e32\u8f6c4\u5b57\u8282\u7f51\u7edc\u5b57\u8282\u5e8f：\u7528inet_addr\u8fd9\u4e2aAPI，\u4e00\u6b65\u5230\u4f4d，\u628a\u70b9\u5206\u5341\u8fdb\u5236\u5b57\u7b26\u4e32\u53d8\u6210\u7f51\u7edc\u5b57\u8282\u5e8f\u768432\u4f4d\u6574\u6570：<\/p>\n
in_addr_t inet_addr(const char *cp); <\/p>\n
\u8f6c\u6362\u539f\u7406，\u62c6\u5f00\u770b\u4e09\u6b65：<\/p>\n
\u7b2c\u4e00\u6b65，\u628a\u5b57\u7b26\u4e32"192.168.1.1"\u6309 . \u5207\u5f00，\u5206\u6210\u56db\u4e2a\u6574\u578b\u90e8\u5206：192\u3001168\u30011\u30011\u3002<\/p>\n
\u7b2c\u4e8c\u6b65，\u6bcf\u4e2a\u90e8\u5206\u5360\u4e00\u4e2a\u5b57\u8282（char），\u56db\u5757\u62fc\u8d77\u6765，\u7ec4\u6210\u4e00\u4e2a32\u4f4d\u6574\u6570\u3002<\/p>\n
\u7b2c\u4e09\u6b65，\u6309\u7f51\u7edc\u4f20\u8f93\u534f\u8bae\u7684\u8981\u6c42，\u628a\u6570\u503c\u8c03\u6574\u6210\u7f51\u7edc\u5b57\u8282\u5e8f，\u4e5f\u5c31\u662f\u5927\u7aef\u5e8f\u3002<\/p>\n
\u53cd\u5411\u8f6c\u6362\u7684\u539f\u7406：<\/p>\n
\u53cd\u8fc7\u6765，\u8981\u628a\u6536\u5230\u768432\u4f4d\u7f51\u7edc\u5b57\u8282\u5e8fIP\u53d8\u56de\u53ef\u8bfb\u5b57\u7b26\u4e32，\u601d\u8def\u4e5f\u4e0d\u590d\u6742，\u7528\u6307\u9488\u5f3a\u8f6c，\u628a\u56db\u4e2a\u5b57\u8282\u4e00\u4e2a\u4e2a\u53d6\u51fa\u6765，\u518d\u6309\u70b9\u5206\u5341\u8fdb\u5236\u7684\u683c\u5f0f\u62fc\u56de\u53bb\u3002<\/p>\n
\u4e00\u4e2a\u5b57\u7b26\u4e32，\u4e00\u4e2a\u6574\u6570，\u4e2d\u95f4\u9694\u7740\u4e00\u9053\u5b57\u8282\u5e8f\u7684\u8f6c\u6362\u3002\u6765\u6765\u56de\u56de，\u7f51\u7edc\u901a\u4fe1\u7684\u5730\u5740\u8bc6\u522b，\u5c31\u9760\u8fd9\u5957\u8f6c\u6362\u5728\u4e24\u7aef\u5bf9\u9f50\u3002<\/p>\n
\u7f51\u7edc\u670d\u52a1\u5668\u901a\u5e38\u5f977\u00d724\u5c0f\u65f6\u8fde\u8f74\u8f6c，\u6240\u4ee5UDP\u670d\u52a1\u5668\u7684\u6838\u5fc3\u903b\u8f91，\u5f80\u5f80\u5c31\u662f\u4e00\u4e2a\u6b7b\u5faa\u73af，\u4e0d\u505c\u5730\u76d1\u542c\u3001\u6536\u5305\u3001\u5904\u7406\u3002\u53ea\u8981\u670d\u52a1\u4e0d\u505c，\u8fd9\u4e2a\u5708\u5c31\u4e00\u76f4\u8f6c\u3002<\/p>\n
Linux\u7ed9\u65e0\u8fde\u63a5\u7684\u6570\u636e\u5305\u63a5\u6536，\u51c6\u5907\u4e86\u4e00\u4e2a\u4e13\u95e8\u7684\u51fd\u6570：recvfrom\u3002<\/p>\n
ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags,
\n struct sockaddr *src_addr, socklen_t *addrlen); <\/p>\n
\u8fd4\u56de\u503c：\u6210\u529f\u65f6，\u8fd4\u56de\u5b9e\u9645\u63a5\u6536\u5230\u7684\u6570\u636e\u5b57\u8282\u6570；\u5982\u679c\u8fde\u63a5\u5173\u95ed\u6216\u51fa\u9519，\u8fd4\u56de-1，\u5e76\u8bbe\u7f6eerrno\u3002<\/p>\n
recvfrom\u4e00\u6536，\u6570\u636e\u5230\u624b，\u53d1\u9001\u65b9\u7684\u5730\u5740\u4e5f\u987a\u5e26\u63e3\u515c\u91cc\u4e86\u3002UDP\u670d\u52a1\u5668\u9760\u5b83，\u624d\u80fd\u5728\u6536\u5230\u6d88\u606f\u4e4b\u540e，\u77e5\u9053\u8be5\u7ed9\u8c01\u56de\u8bdd\u3002<\/p>\n
\u4e0a\u6587\u6211\u4eec\u628aUDP\u5957\u63a5\u5b57\u7684\u57fa\u7840\u6982\u5ff5\u3001\u5957\u63a5\u5b57\u521b\u5efa\u548c\u6570\u636e\u7ed3\u6784\u634b\u4e86\u4e00\u904d\u3002\u63a5\u4e0b\u6765，\u5c31\u6b63\u5f0f\u8fdb\u5165UDP\u670d\u52a1\u5668\u7684\u521d\u59cb\u5316\u7ed1\u5b9a（bind）\u3001\u6570\u636e\u6536\u53d1（recvfrom \u4e0e sendto），\u4ee5\u53ca\u5ba2\u6237\u7aef\u8bf7\u6c42\u673a\u5236\u80cc\u540e\u7684\u5e95\u5c42\u903b\u8f91\u3002<\/p>\n
\u8981\u521b\u5efa\u4e00\u4e2aUDP\u670d\u52a1\u5668，\u7b2c\u4e00\u6b65\u5c31\u662f\u5b8c\u6210\u5957\u63a5\u5b57\u521d\u59cb\u5316，\u7136\u540e\u628a\u7279\u5b9a\u7684IP\u548c\u7aef\u53e3\u4fe1\u606f\u7ed1\u5b9a（Bind）\u5230\u5185\u6838\u91cc\u3002\u5730\u5740\u4e0d\u7ed1\u4e0a，\u5ba2\u6237\u7aef\u5c31\u627e\u4e0d\u5230\u4f60\u3002<\/p>\n
\u5728\u586b\u5145struct sockaddr_in\u4e4b\u524d，\u901a\u5e38\u5f97\u5148\u628a\u7ed3\u6784\u4f53\u5360\u7528\u7684\u5185\u5b58\u6e05\u96f6，\u514d\u5f97\u6b8b\u7559\u7684\u810f\u6570\u636e\u6df7\u8fdb\u53bb，\u628a\u901a\u4fe1\u6405\u4e71\u3002Linux\u73af\u5883\u4e0b，\u53ef\u4ee5\u7528\u4e0b\u9762\u8fd9\u4e24\u4e2a\u51fd\u6570：<\/p>\n
#include <strings.h><\/p>\n
void bzero(void *s, size_t n);
\nvoid explicit_bzero(void *s, size_t n); <\/p>\n
\u670d\u52a1\u5668\u521d\u59cb\u5316\u9636\u6bb5，\u5148\u628a\u5957\u63a5\u5b57\u5730\u5740\u7ed3\u6784\u4f53\u6e05\u96f6：<\/p>\n
struct sockaddr_in local;
\nbzero(&local, sizeof(local)); <\/p>\n
\u5f53\u7136，\u7528memset\u6765\u8bbe\u7f6e\u4e5f\u4e00\u6837，\u6548\u679c\u5b8c\u5168\u76f8\u540c\u3002<\/p>\n
\u670d\u52a1\u5668\u7aef\u5f97\u660e\u786e\u544a\u8bc9\u5185\u6838\u4e09\u4ef6\u4e8b：\u76d1\u542c\u54ea\u4e2a\u534f\u8bae\u65cf\u3001\u7528\u54ea\u4e2a\u7aef\u53e3\u53f7\u3001\u7ed1\u54ea\u4e2aIP\u5730\u5740\u3002\u53ef\u4e3b\u673a\u548c\u7f51\u7edc\u7684\u5b57\u8282\u5e8f\u672a\u5fc5\u4e00\u81f4，\u5927\u7aef\u5c0f\u7aef，\u5404\u8bf4\u5404\u8bdd\u3002\u6240\u4ee5，\u4e3b\u673a\u6570\u636e\u5fc5\u987b\u5148\u8f6c\u6210\u7f51\u7edc\u5b57\u8282\u5e8f（\u5927\u7aef），\u624d\u80fd\u51fa\u95e8\u3002<\/p>\n
\u7aef\u53e3\u53f7\u8f6c\u6362：\u7528htons(port)，\u628a\u4e3b\u673a\u5b57\u8282\u5e8f\u768416\u4f4d\u6574\u6570\u8f6c\u6210\u7f51\u7edc\u5b57\u8282\u5e8f\u3002<\/p>\n<\/li>\n
IP \u5730\u5740\u8f6c\u6362：\u7528inet_addr(ip_str.c_str())，\u628a\u70b9\u5206\u5341\u8fdb\u5236\u5b57\u7b26\u4e32\u8f6c\u6210\u7f51\u7edc\u5b57\u8282\u5e8f\u768432\u4f4d\u6574\u6570\u3002<\/p>\n<\/li>\n<\/ul>\n
local.sin_family = AF_INET;
\nlocal.sin_port = htons(_port);
\nlocal.sin_addr.s_addr = inet_addr(_ip.c_str()); <\/p>\n
\u4e09\u884c\u586b\u5b8c，\u5730\u5740\u7ed3\u6784\u4f53\u7684\u201c\u7075\u9b42\u201d\u5c31\u9f50\u4e86\u3002\u534f\u8bae\u65cf\u3001\u7aef\u53e3\u3001IP，\u5404\u5c31\u5404\u4f4d\u3002<\/p>\n
\u5730\u5740\u7ed3\u6784\u4f53\u586b\u597d\u4e86，\u8fd8\u5f97\u628a\u5b83\u8ddf\u5957\u63a5\u5b57\u7ed1\u5728\u4e00\u8d77\u3002\u8fd9\u4e00\u6b65，\u9760bind()\u7cfb\u7edf\u8c03\u7528：<\/p>\n
int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen); <\/p>\n
\u5b83\u505a\u7684\u4e8b\u60c5\u5f88\u76f4\u63a5：\u628a\u521b\u5efa\u597d\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26_sockfd，\u8ddf\u672c\u5730\u7f51\u7edc\u5730\u5740（IP + \u7aef\u53e3）\u5f3a\u5173\u8054\u8d77\u6765\u3002\u4ece\u6b64，\u8fd9\u4e2a\u5957\u63a5\u5b57\u5c31\u8ba4\u51c6\u4e86\u8fd9\u4e2a\u5730\u5740\u3002<\/p>\n
\u4ee3\u7801\u5b9e\u73b0\u4e0e\u6821\u9a8c\u903b\u8f91：<\/p>\n
int n = bind(_sockfd, (struct sockaddr*)&local, sizeof(local));
\nif (n < 0) {
\n LOG(LogLevel::FATAL) << "bind error";
\n exit(2);
\n} <\/p>\n
\u6ce8\u610f\u4e00\u4e2a\u7ec6\u8282：bind\u7684\u7b2c\u4e8c\u4e2a\u53c2\u6570，\u8981\u6c42\u662f\u901a\u7528\u5957\u63a5\u5b57\u6307\u9488\u7c7b\u578bstruct sockaddr*\u3002\u6240\u4ee5，\u4f20\u5165struct sockaddr_in\u7ed3\u6784\u4f53\u5730\u5740\u65f6，\u5f97\u505a\u4e00\u6b21\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u3002<\/p>\n
\u8fd9\u5176\u5b9e\u5c31\u662fC\u8bed\u8a00\u7248\u7684\u201c\u6307\u9488\u591a\u6001\u201d，\u5b50\u7c7b\u578b\u6307\u9488\u8f6c\u6210\u7236\u7c7b\u578b\u6307\u9488，\u51fd\u6570\u62ff\u5230\u901a\u7528\u5916\u58f3\u540e，\u6839\u636e\u5185\u90e8\u7684sin_family\u5b57\u6bb5，\u518d\u51b3\u5b9a\u6309\u54ea\u5957\u89c4\u5219\u89e3\u8bfb\u3002\u4f20\u7684\u65f6\u5019\u662fsockaddr_in，\u7528\u7684\u65f6\u5019\u8fd8\u662fsockaddr_in，\u4e2d\u95f4\u90a3\u5c42sockaddr*\u53ea\u662f\u4e2a\u901a\u7528\u5165\u53e3\u3002<\/p>\n
UDP\u5957\u63a5\u5b57\u6587\u4ef6\u63cf\u8ff0\u7b26sockfd，\u65e2\u80fd\u8bfb，\u4e5f\u80fd\u5199\u3002\u8bfb，\u5c31\u662f\u6536\u6570\u636e；\u5199，\u5c31\u662f\u53d1\u6570\u636e\u3002\u8fd9\u4e00\u8bfb\u4e00\u5199，\u5c31\u51b3\u5b9a\u4e86UDP\u901a\u4fe1\u662f\u5168\u53cc\u5de5（Full-Duplex）\u7684\u3002<\/p>\n
\u670d\u52a1\u7aef7\u00d724\u5c0f\u65f6\u8fde\u8f74\u8f6c，\u6b7b\u5faa\u73af\u91cc\u4e0d\u505c\u6b47，\u9760\u7684\u5c31\u662frecvfrom\u6293\u53d6\u5ba2\u6237\u7aef\u53d1\u6765\u7684\u6570\u636e\u3002<\/p>\n
ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags,
\n struct sockaddr *src_addr, socklen_t *addrlen); <\/p>\n
\u963b\u585eIO\u7684\u884c\u4e3a\u7279\u5f81：\u5f53flags\u8bbe\u4e3a0\u65f6，recvfrom\u5c31\u662f\u963b\u585e\u5f0fIO（Blocking IO）\u3002\u5ba2\u6237\u7aef\u6ca1\u53d1\u6570\u636e？\u90a3\u670d\u52a1\u7aef\u8fdb\u7a0b\u5c31\u5728\u8fd9\u513f\u6302\u7740，\u4e00\u76f4\u7b49\u3002\u8ddfC\u8bed\u8a00\u91ccscanf\u7b49\u952e\u76d8\u8f93\u5165\u7684\u611f\u89c9\u4e00\u6a21\u4e00\u6837，\u6ca1\u8f93\u5165，\u5b83\u5c31\u4e0d\u5f80\u4e0b\u8d70\u3002\u76f4\u5230\u7f51\u7edc\u7f13\u51b2\u533a\u91cc\u6765\u4e86\u6570\u636e，\u5b83\u624d\u9192\u8fc7\u6765\u3002<\/p>\n
\u591a\u5bf9\u4e00\u901a\u4fe1：\u600e\u4e48\u77e5\u9053\u6570\u636e\u662f\u8c01\u53d1\u7684？<\/p>\n
\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668，\u901a\u5e38\u662f\u591a\u5bf9\u4e00\u7684\u5173\u7cfb\u3002\u4e00\u4e2a\u670d\u52a1\u5668，\u5bf9\u5e94\u4e00\u5806\u5ba2\u6237\u7aef\u3002\u670d\u52a1\u5668\u5904\u7406\u6570\u636e\u65f6，\u4e0d\u5149\u8981\u62ff\u5230\u5ba2\u6237\u7aef\u53d1\u6765\u7684\u201c\u6587\u672c\u6570\u636e\u201d（\u5b58\u5728buf\u91cc），\u8fd8\u5f97\u641e\u6e05\u695a，\u8fd9\u6570\u636e\u662f\u8c01\u53d1\u7684？\u5ba2\u6237\u7aef\u7684IP\u548c\u7aef\u53e3，\u4e00\u4e2a\u90fd\u4e0d\u80fd\u5c11\u3002<\/p>\n
\u670d\u52a1\u5668\u8981\u7ed9\u5ba2\u6237\u7aef\u56de\u6d88\u606f，\u6216\u8005\u5ba2\u6237\u7aef\u8981\u7ed9\u670d\u52a1\u5668\u53d1\u6570\u636e，\u90fd\u7528sendto\u8fd9\u4e2a\u7cfb\u7edf\u8c03\u7528：<\/p>\n
ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
\n const struct sockaddr *dest_addr, socklen_t addrlen); <\/p>\n
\u53c2\u6570\u8be6\u89e3<\/p>\n
\u8fd4\u56de\u503c<\/p>\n
\u6210\u529f\u65f6，\u8fd4\u56de\u5b9e\u9645\u53d1\u9001\u7684\u5b57\u8282\u6570；\u51fa\u9519\u65f6，\u8fd4\u56de-1，\u5e76\u8bbe\u7f6eerrno\u3002<\/p>\n
\u4e0d\u8fc7\u6709\u4e00\u70b9\u5f97\u8bf4\u6e05\u695a：UDP\u662f\u65e0\u8fde\u63a5\u7684\u3002sendto\u6210\u529f\u8c03\u7528，\u53ea\u610f\u5473\u7740\u6570\u636e\u88ab\u4ea4\u7ed9\u4e86\u64cd\u4f5c\u7cfb\u7edf\u7684\u7f51\u7edc\u6808\u53bb\u53d1\u9001，\u5e76\u4e0d\u4fdd\u8bc1\u5bf9\u7aef\u4e00\u5b9a\u80fd\u6536\u5230\u3002\u53d1\u51fa\u53bb，\u5c31\u7b97\u4ea4\u5dee\u4e86\u3002\u81f3\u4e8e\u8def\u4e0a\u4f1a\u4e0d\u4f1a\u4e22，\u80fd\u4e0d\u80fd\u5230，UDP\u672c\u8eab\u4e0d\u95fb\u4e0d\u95ee\u3002<\/p>\n
\u5ba2\u6237\u7aef\u8981\u8bbf\u95eeUDP\u670d\u52a1\u7aef，\u9996\u5148\u5f97\u62ff\u5230\u670d\u52a1\u7aef\u7684IP\u5730\u5740\u548c\u7aef\u53e3\u53f7\u3002\u8fd9\u662f\u6572\u95e8\u7816，\u6ca1\u6709\u5b83，\u8fde\u95e8\u90fd\u627e\u4e0d\u5230\u3002<\/p>\n
\u5ba2\u6237\u7aef\u600e\u4e48\u77e5\u9053\u670d\u52a1\u7aef\u7684IP\u548c\u7aef\u53e3？<\/p>\n
\u5b9e\u9645\u5f00\u53d1\u4e2d，\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u7aef\u7a0b\u5e8f\u901a\u5e38\u51fa\u81ea\u540c\u4e00\u5bb6\u516c\u53f8，\u6216\u8005\u540c\u4e00\u4e2a\u5f00\u53d1\u56e2\u961f\u3002\u670d\u52a1\u7aef\u7684IP\u5730\u5740\u548c\u9ed8\u8ba4\u7aef\u53e3\u53f7，\u4e00\u822c\u4f1a\u76f4\u63a5\u786c\u7f16\u7801\u5728\u5ba2\u6237\u7aef\u4ee3\u7801\u91cc；\u4e5f\u53ef\u4ee5\u901a\u8fc7\u57df\u540d\u89e3\u6790（DNS），\u6216\u8005\u4ece\u914d\u7f6e\u6587\u4ef6\u91cc\u52a8\u6001\u52a0\u8f7d\u3002\u600e\u4e48\u65b9\u4fbf\u600e\u4e48\u6765，\u5173\u952e\u662f\u628a\u5730\u5740\u5148\u5b9a\u4e0b\u6765\u3002<\/p>\n
\u670d\u52a1\u7aef\u5fc5\u987b\u663e\u5f0f\u8c03\u7528bind()，\u628a\u56fa\u5b9a\u7aef\u53e3\u7ed1\u6b7b，\u4e0d\u7136\u5ba2\u6237\u7aef\u627e\u4e0d\u5230\u5b83\u3002\u53ef\u5ba2\u6237\u7aef\u4e0d\u4e00\u6837，\u901a\u5e38\u4e0d\u9700\u8981\u663e\u5f0fbind()\u3002<\/p>\n
\u539f\u56e0\u6709\u4e24\u70b9：<\/p>\n
\u7b2c\u4e00，\u5982\u679c\u5ba2\u6237\u7aef\u663e\u5f0f\u7ed1\u5b9a\u56fa\u5b9a\u7aef\u53e3，\u5f88\u53ef\u80fd\u8ddf\u7528\u6237\u673a\u5668\u4e0a\u5176\u4ed6\u6b63\u5728\u8fd0\u884c\u7684\u7a0b\u5e8f\u649e\u7aef\u53e3，\u5bfc\u81f4\u5ba2\u6237\u7aef\u542f\u52a8\u5931\u8d25\u3002\u7528\u6237\u673a\u5668\u4e0a\u8dd1\u7740\u4ec0\u4e48，\u8c01\u4e5f\u8bf4\u4e0d\u51c6，\u786c\u7ed1\u4e00\u4e2a\u7aef\u53e3，\u7b49\u4e8e\u7ed9\u81ea\u5df1\u57cb\u96f7\u3002<\/p>\n
\u7b2c\u4e8c，\u5ba2\u6237\u7aef\u5728\u7b2c\u4e00\u6b21\u8c03\u7528sendto()\u53d1\u9001\u6570\u636e\u5305\u65f6，\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u4f1a\u81ea\u52a8\u3001\u968f\u673a\u5730\u7ed9\u5b83\u5206\u914d\u4e00\u4e2a\u552f\u4e00\u7684\u7a7a\u95f2\u7aef\u53e3\u53f7，\u987a\u5e26\u5b8c\u6210\u9690\u5f0f\u7ed1\u5b9a\u3002\u4e0d\u7528\u5ba2\u6237\u7aef\u64cd\u5fc3，\u5185\u6838\u5168\u5305\u4e86\u3002<\/p>\n
\u6240\u4ee5，\u670d\u52a1\u7aef\u7ed1\u5b9a\u662f\u4e3a\u4e86\u201c\u88ab\u627e\u5230\u201d，\u5ba2\u6237\u7aef\u4e0d\u7ed1\u5b9a\u662f\u4e3a\u4e86\u201c\u4e0d\u649e\u8f66\u201d\u3002\u4e00\u4e2a\u6c42\u7a33，\u4e00\u4e2a\u6c42\u6d3b\u3002<\/p>\n
\u524d\u6587\u628a UDP \u7684\u57fa\u7840 API \u548c\u6838\u5fc3\u901a\u4fe1\u6d41\u7a0b\u8bb2\u5b8c\u4e86\u3002\u63a5\u4e0b\u6765，\u6709\u51e0\u4e2a\u5173\u4e8e\u5957\u63a5\u5b57\u7ed1\u5b9a\u7684\u7ecf\u5178\u7591\u95ee，\u5f97\u597d\u597d\u63b0\u626f\u63b0\u626f：\u5ba2\u6237\u7aef\u5230\u5e95\u9700\u4e0d\u9700\u8981 bind？\u4e3a\u4ec0\u4e48\u5ba2\u6237\u7aef\u4e0d\u80fd\u663e\u5f0f bind？\u670d\u52a1\u5668\u53c8\u4e3a\u4ec0\u4e48\u5fc5\u987b\u663e\u5f0f bind？<\/p>\n
\u7ed3\u8bba\u5148\u8bf4：\u5ba2\u6237\u7aef\u9700\u8981bind，\u4f46\u7edd\u5bf9\u4e0d\u9700\u8981\u201c\u663e\u5f0f（\u624b\u52a8）bind\u201d\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u9700\u8981bind？<\/p>\n
\u4efb\u4f55\u7f51\u7edc\u901a\u4fe1，\u5728\u4f20\u8f93\u5c42\u90fd\u5f97\u660e\u786e\u6807\u8bc6\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u3002IP\u5730\u5740\u8d1f\u8d23\u5728\u7f51\u7edc\u4e2d\u5b9a\u4f4d\u4e3b\u673a，\u7aef\u53e3\u53f7\u8d1f\u8d23\u5728\u4e3b\u673a\u4e0a\u552f\u4e00\u6807\u8bc6\u4e00\u4e2a\u901a\u4fe1\u8fdb\u7a0b\u3002\u5ba2\u6237\u7aef\u53d1\u6570\u636e\u5305\u7684\u65f6\u5019，\u5fc5\u987b\u5e26\u4e0a\u201c\u6e90IP + \u6e90\u7aef\u53e3\u201d，\u4e0d\u7136\u670d\u52a1\u5668\u5904\u7406\u5b8c\u8bf7\u6c42，\u538b\u6839\u4e0d\u77e5\u9053\u5f80\u54ea\u513f\u56de\u8bdd\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u7531\u64cd\u4f5c\u7cfb\u7edf\u9690\u5f0f\u5b8c\u6210？<\/p>\n
\u8fd9\u91cc\u9762\u6709\u4e24\u5c42\u8003\u8651\u3002<\/p>\n
\u7b2c\u4e00，\u64cd\u4f5c\u7cfb\u7edf\u4e0d\u4fe1\u4efb\u7528\u6237\u3002 \u5982\u679c\u5141\u8bb8\u5ba2\u6237\u7aef\u4ee3\u7801\u663e\u5f0f\u5199\u6b7b\u7aef\u53e3\u53f7，\u64cd\u4f5c\u7cfb\u7edf\u6ca1\u6cd5\u4fdd\u8bc1\u8fd9\u4e2a\u7aef\u53e3\u5728\u7528\u6237\u673a\u5668\u4e0a\u6ca1\u88ab\u522b\u7684\u7a0b\u5e8f\u5360\u7740\u3002\u7aef\u53e3\u51b2\u7a81\u4e00\u65e6\u53d1\u751f，\u4e00\u4e2a\u7aef\u53e3\u53ea\u80fd\u88ab\u4e00\u4e2a\u8fdb\u7a0bbind，\u5ba2\u6237\u7aef\u7a0b\u5e8f\u5f53\u573a\u542f\u52a8\u5931\u8d25\u3002\u7528\u6237\u673a\u5668\u4e0a\u8dd1\u7740\u4ec0\u4e48，\u8c01\u4e5f\u8bf4\u4e0d\u51c6，\u786c\u7ed1\u4e00\u4e2a\u7aef\u53e3，\u7b49\u4e8e\u7ed9\u81ea\u5df1\u57cb\u96f7\u3002<\/p>\n
\u7b2c\u4e8c，\u968f\u673a\u7aef\u53e3\u673a\u5236\u66f4\u7701\u5fc3\u3002 \u5ba2\u6237\u7aef\u7b2c\u4e00\u6b21\u8c03\u7528sendto()\u53d1\u6d88\u606f\u65f6，\u5185\u6838\u4f1a\u81ea\u52a8\u83b7\u53d6\u672c\u673aIP，\u518d\u4ece\u5f53\u524d\u7a7a\u95f2\u7684\u52a8\u6001\u7aef\u53e3\u6c60\u91cc，\u968f\u673a\u6311\u4e00\u4e2a\u6ca1\u88ab\u5360\u7528\u7684\u7aef\u53e3，\u5206\u914d\u7ed9\u8fd9\u4e2a\u5957\u63a5\u5b57，\u987a\u624b\u5b8c\u6210bind\u64cd\u4f5c\u3002<\/p>\n
\u7aef\u53e3\u503c\u5bf9\u5ba2\u6237\u7aef\u6765\u8bf4，\u65e0\u5173\u7d27\u8981\u3002 \u5177\u4f53\u5360\u54ea\u4e2a\u7aef\u53e3\u4e0d\u91cd\u8981，\u53ea\u8981\u5728\u8fd9\u6b21\u901a\u4fe1\u8fc7\u7a0b\u4e2d，\u8fd9\u4e2a\u7aef\u53e3\u662f\u552f\u4e00\u7684\u5c31\u884c\u3002\u5ba2\u6237\u7aef\u5728\u4e4e\u7684\u662f\u201c\u80fd\u53d1\u51fa\u53bb\u3001\u80fd\u6536\u56de\u6765\u201d，\u7aef\u53e3\u53f7\u662f\u51e0，\u65e0\u6240\u8c13\u3002<\/p>\n
\u8ddf\u5ba2\u6237\u7aef\u6b63\u597d\u76f8\u53cd，\u670d\u52a1\u5668\u7aef\u5fc5\u987b\u663e\u5f0f\u8c03\u7528bind()，\u6307\u5b9a\u56fa\u5b9a\u4e14\u4f17\u6240\u5468\u77e5\u7684IP\u548c\u7aef\u53e3\u53f7\u3002<\/p>\n
\u670d\u52a1\u5668\u7684\u5bf9\u5916\u670d\u52a1\u5c5e\u6027\u3002 \u670d\u52a1\u5668\u662f\u4e3a\u4e0d\u7279\u5b9a\u7684\u4f17\u591a\u5ba2\u6237\u7aef\u63d0\u4f9b\u670d\u52a1\u7684\u3002\u5ba2\u6237\u7aef\u60f3\u4e3b\u52a8\u53d1\u8d77\u8bf7\u6c42，\u524d\u63d0\u662f，\u5b83\u5f97\u5728\u53d1\u9001\u4e4b\u524d，\u5c31\u77e5\u9053\u670d\u52a1\u5668\u7684IP\u548c\u7aef\u53e3\u53f7\u3002\u5730\u5740\u4e0d\u660e\u786e，\u5ba2\u6237\u7aef\u8fde\u95e8\u90fd\u627e\u4e0d\u5230\u3002<\/p>\n
\u4f17\u6240\u5468\u77e5，\u4e14\u4e0d\u53ef\u8f7b\u6613\u6539\u53d8\u3002 \u670d\u52a1\u5668\u7684IP\u5730\u5740\u548c\u7aef\u53e3\u53f7，\u5fc5\u987b\u662f\u56fa\u5b9a\u7684\u3002HTTP\u768480\u3001HTTPS\u7684443，\u90fd\u662f\u4f17\u6240\u5468\u77e5\u7684\u56fa\u5b9a\u670d\u52a1\u7aef\u53e3\u3002\u81ea\u5b9a\u4e49\u670d\u52a1\u4e5f\u4e00\u6837，\u7aef\u53e3\u4e00\u65e6\u5b9a\u4e0b\u6765，\u5c31\u4e0d\u80fd\u968f\u4fbf\u6539\u3002<\/p>\n
\u8981\u662f\u670d\u52a1\u5668\u6bcf\u6b21\u91cd\u542f，\u90fd\u7531\u64cd\u4f5c\u7cfb\u7edf\u968f\u673a\u5206\u914d\u7aef\u53e3，\u5ba2\u6237\u7aef\u5c31\u5f7b\u5e95\u61f5\u4e86，\u5b83\u4e0d\u77e5\u9053\u670d\u52a1\u5668\u8dd1\u5230\u54ea\u4e2a\u7aef\u53e3\u4e0a\u53bb\u4e86，\u8fde\u63a5\u6839\u672c\u5efa\u4e0d\u8d77\u6765\u3002<\/p>\n
\u540e\u679c\u5f88\u4e25\u91cd\u3002 \u5982\u679c\u670d\u52a1\u5668\u968f\u610f\u53d8\u66f4\u7aef\u53e3，\u6216\u8005\u538b\u6839\u6ca1\u505a\u663e\u5f0f bind，\u77ed\u65f6\u95f4\u5185，\u6240\u6709\u4f9d\u8d56\u8fd9\u4e2a\u7aef\u53e3\u7684\u5ba2\u6237\u7aef\u90fd\u4f1a\u6389\u7ebf，\u670d\u52a1\u76f4\u63a5\u4e2d\u65ad\u3002<\/p>\n
\u4e00\u4e2a\u7ed1\u5b9a，\u4e24\u79cd\u547d\u8fd0\u3002\u5ba2\u6237\u7aef\u6c42\u6d3b，\u670d\u52a1\u7aef\u6c42\u7a33\u3002\u6838\u5fc3\u5c31\u4e00\u53e5\u8bdd：\u670d\u52a1\u7aef\u8981\u201c\u88ab\u627e\u5230\u201d，\u5ba2\u6237\u7aef\u8981\u201c\u4e0d\u649e\u8f66\u201d\u3002<\/p>\n
\u5b9e\u9645\u5f00\u53d1\u91cc，\u670d\u52a1\u5668\u7aef\u7684IP\u7ed1\u5b9a\u7b56\u7565\u85cf\u7740\u4e0d\u5c11\u5751\u3002\u63a5\u4e0b\u6765\u6211\u4eec\u6df1\u5165\u5206\u6790\u4e91\u670d\u52a1\u5668\u73af\u5883\u4e0b\u7684IP\u7ed1\u5b9a\u7ea6\u675f\u3001INADDR_ANY\u7684\u5e95\u5c42\u903b\u8f91\u3001\u5e94\u7528\u5c42\u8f6f\u4ef6\u7684\u5206\u5c42\u8bbe\u8ba1，\u4ee5\u53ca\u5730\u5740\u8f6c\u6362\u51fd\u6570\u7684\u7ebf\u7a0b\u5b89\u5168\u6f14\u8fdb\u3002<\/p>\n
\u5b9e\u9645\u90e8\u7f72UDP\u670d\u52a1\u5668\u65f6，\u76f4\u63a5\u6307\u5b9a\u5177\u4f53\u7684IP\u5730\u5740，\u4e0d\u7ba1\u662f\u516c\u7f51IP\u8fd8\u662f\u67d0\u4e2a\u5177\u4f53\u7684\u5185\u7f51IP，\u5f80\u5f80\u4f1a\u649e\u4e0a\u5404\u79cd\u7ed1\u5b9a\u9519\u8bef\u6216\u8005\u8bbf\u95ee\u9650\u5236\u3002<\/p>\n
\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2502 \u4e91\u670d\u52a1\u5668 (\u4e3b\u673a) \u2502
\n \u2502 \u2502
\n [\u5ba2\u6237\u7aef\u8bbf\u95ee] \u2500\u2500\u2500> \u2502 \u7f51\u53611: \u672c\u5730\u73af\u56de 127.0.0.1 \u2502
\n \u2502 \u7f51\u53612: \u5185\u7f51 IP (\u79c1\u7f51) \u2502
\n \u2502 (\u516c\u7f51 IP \u6302\u8f7d\u5728\u5916\u90e8\u7f51\u5173) \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
\n \u2502
\n \u63a8\u8350\u4f7f\u7528 INADDR_ANY (0.0.0.0)
\n \u76d1\u542c\u53d1\u9001\u5230\u672c\u673a\u6240\u6709\u7f51\u5361\u7684\u6570\u636e <\/p>\n
\u76f4\u63a5bind\u516c\u7f51IP\u2014\u2014\u5931\u8d25\u3002<\/p>\n
\u5728\u4e91\u5382\u5546（\u963f\u91cc\u4e91\u3001\u817e\u8baf\u4e91\u8fd9\u4e9b）\u63d0\u4f9b\u7684\u4e91\u670d\u52a1\u5668\u4e0a，\u7269\u7406\u7f51\u5361\u6216\u865a\u62df\u7f51\u5361\u4e0a\u914d\u7f6e\u7684，\u901a\u5e38\u662f\u5185\u7f51 IP（\u79c1\u7f51IP）\u3002\u516c\u7f51IP\u662f\u901a\u8fc7NAT（\u7f51\u7edc\u5730\u5740\u8f6c\u6362）\u6620\u5c04\u5230\u4e91\u670d\u52a1\u5668\u4e0a\u7684，\u5b83\u5e76\u6ca1\u6709\u76f4\u63a5\u914d\u7f6e\u5230\u4e91\u670d\u52a1\u5668\u7684\u672c\u5730\u7f51\u5361\u8bbe\u5907\u4e0a\u3002\u6240\u4ee5，\u5728\u4ee3\u7801\u91cc\u663e\u5f0fbind\u516c\u7f51IP，\u7cfb\u7edf\u4f1a\u76f4\u63a5\u62a5\u9519，\u7529\u4f60\u4e00\u53e5bind error\u3002<\/p>\n
bind 127.0.0.1\u6216\u7279\u5b9a\u5185\u7f51IP\u2014\u2014\u5c40\u9650\u6027\u592a\u5927\u3002<\/p>\n
\u5982\u679cbind\u4e86127.0.0.1（\u672c\u5730\u73af\u56de\u5730\u5740），\u6570\u636e\u5305\u53ea\u80fd\u5728\u64cd\u4f5c\u7cfb\u7edf\u5185\u90e8\u8f6c\u5708，\u4ec5\u5141\u8bb8\u540c\u4e00\u53f0\u673a\u5668\u4e0a\u7684\u5ba2\u6237\u7aef\u8bbf\u95ee\u3002\u5916\u754c\u8de8\u7f51\u7edc，\u6839\u672c\u8fdb\u4e0d\u6765\u3002<\/p>\n
\u5982\u679cbind\u4e86\u5177\u4f53\u7684\u5185\u7f51IP，\u90a3\u5ba2\u6237\u7aef\u7528127.0.0.1\u53d1\u6570\u636e，\u6536\u4e0d\u5230；\u53cd\u8fc7\u6765\u4e5f\u4e00\u6837\u3002\u663e\u5f0f\u7ed1\u5b9a\u67d0\u4e2a\u7279\u5b9a\u5730\u5740\u4e4b\u540e，\u5ba2\u6237\u7aef\u5c31\u5fc5\u987b\u4e14\u53ea\u80fd\u901a\u8fc7\u8fd9\u4e2a\u5730\u5740\u624d\u80fd\u6210\u529f\u8bbf\u95ee\u3002\u4e00\u6761\u8def\u8d70\u5230\u9ed1，\u522b\u7684\u95e8\u90fd\u5173\u4e86\u3002<\/p>\n
\u8981\u89e3\u51b3\u4e0a\u9762\u8fd9\u4e9b\u9ebb\u70e6，\u670d\u52a1\u5668\u521d\u59cb\u5316sockaddr_in\u7ed3\u6784\u4f53\u7684\u65f6\u5019，\u5c31\u522b\u7ed1\u5b9a\u5177\u4f53\u7684\u9759\u6001IP\u5730\u5740\u4e86，\u6539\u7528INADDR_ANY：<\/p>\n
\/\/ \u5728\u5b8f\u5b9a\u4e49\u4e2d，INADDR_ANY \u5373\u4e3a 0x00000000（\u5168 0 \u5730\u5740）
\n#define INADDR_ANY ((in_addr_t) 0x00000000)<\/p>\n
\/\/ \u670d\u52a1\u5668\u7aef\u521d\u59cb\u5316\u4ee3\u7801：
\nlocal.sin_addr.s_addr = INADDR_ANY; \/\/ \u81ea\u52a8\u8f6c\u6362\u4e3a\u7f51\u7edc\u5b57\u8282\u5e8f\u7684\u5168 0 <\/p>\n
INADDR_ANY \u7684\u4f18\u52bf\u4e0e\u5e95\u5c42\u539f\u7406：<\/p>\n
\u591a\u7f51\u5361\u76d1\u542c\u3002\u4e00\u53f0\u670d\u52a1\u5668\u53ef\u80fd\u6302\u8f7d\u591a\u5757\u7269\u7406\u7f51\u5361\u6216\u865a\u62df\u7f51\u5361，\u6bd4\u5982\u62e5\u6709\u5185\u7f51IP\u3001\u73af\u56de\u5730\u5740IP\u7b49\u3002\u6307\u5b9aINADDR_ANY\u4e4b\u540e，\u64cd\u4f5c\u7cfb\u7edf\u5185\u6838\u4f1a\u76d1\u542c\u6240\u6709\u5230\u8fbe\u8fd9\u53f0\u4e3b\u673a\u3001\u4e14\u76ee\u6807\u7aef\u53e3\u5339\u914d\u7684UDP\u6570\u636e\u5305，\u4e0d\u7ba1\u5b83\u662f\u4ece\u54ea\u5757\u7f51\u5361\u8fdb\u6765\u7684\u3002<\/p>\n
\u8de8\u7f51\u7edc\u8bbf\u95ee\u901a\u7545\u3002\u65e0\u8bba\u662f\u901a\u8fc7\u5185\u7f51IP\u3001\u516c\u7f51IP\u7684NAT\u6620\u5c04，\u8fd8\u662f\u901a\u8fc7\u672c\u5730\u73af\u56de\u5730\u5740127.0.0.1\u8bbf\u95ee\u8fd9\u4e2a\u7aef\u53e3，\u670d\u52a1\u5668\u90fd\u80fd\u6b63\u5e38\u63a5\u6536\u5e76\u54cd\u5e94\u3002\u6765\u8005\u4e0d\u62d2，\u6761\u6761\u5927\u8def\u901a\u7f57\u9a6c\u3002<\/p>\n
\u5199\u9ad8\u53ef\u9760\u7684\u670d\u52a1\u5668\u7a0b\u5e8f，\u7f51\u7edc\u901a\u4fe1\u903b\u8f91（\u6536\u53d1\u6570\u636e）\u548c\u4e0a\u5c42\u4e1a\u52a1\u5904\u7406（\u8ba1\u7b97\u3001\u6570\u636e\u5e93\u4ea4\u4e92\u7b49）\u5e94\u8be5\u89e3\u8026（Decoupling）\u3002<\/p>\n
\u670d\u52a1\u5668\u7684\u6838\u5fc3\u5de5\u4f5c\u5faa\u73af，\u5206\u4e09\u6b65：<\/p>\n
\u63a5\u6536\u6570\u636e：\u901a\u8fc7recvfrom\u83b7\u53d6\u5ba2\u6237\u7aef\u6570\u636e\u5305，\u4ee5\u53ca\u5ba2\u6237\u7aef\u7684sockaddr_in\u5730\u5740（\u5bf9\u7aef\u4fe1\u606f）\u3002<\/p>\n<\/li>\n
\u4e1a\u52a1\u5904\u7406：\u628a\u63a5\u6536\u5230\u7684\u539f\u59cb\u6570\u636e，\u4f20\u7ed9\u4e0a\u5c42\u56de\u8c03\u51fd\u6570\u6216\u8005\u4e1a\u52a1\u903b\u8f91\u6a21\u5757\u53bb\u5904\u7406\u3002<\/p>\n<\/li>\n
\u54cd\u5e94\u53d1\u9001：\u901a\u8fc7sendto，\u628a\u4e0a\u5c42\u5904\u7406\u5b8c\u6bd5\u7684\u7ed3\u679c\u53d1\u56de\u7ed9\u5ba2\u6237\u7aef\u3002<\/p>\n<\/li>\n
UDP\u670d\u52a1\u5668\u5728\u7c7b\u5b9a\u4e49\u91cc\u7ef4\u62a4\u4e00\u4e2a\u51fd\u6570\u5bf9\u8c61，\u6bd4\u5982std::function<std::string(const std::string&)>，\u628a\u6570\u636e\u5904\u7406\u7684\u5177\u4f53\u903b\u8f91\u4ea4\u7ed9\u5916\u90e8\u4e0a\u5c42\u4f20\u5165：<\/p>\n
#include <functional>
\n#include <string><\/p>\n
\/\/ \u5b9a\u4e49\u4e1a\u52a1\u5904\u7406\u51fd\u6570\u7c7b\u578b
\nusing func_t = std::function<std::string(const std::string&)>;<\/p>\n
class UdpServer {
\npublic:
\n UdpServer(uint16_t port, func_t func)
\n : _port(port), _func(func), _isrunning(false) {}<\/p>\n
void Start() {
\n _isrunning = true;
\n char buffer[1024];<\/p>\n
while (_isrunning) {
\n struct sockaddr_in peer;
\n socklen_t len = sizeof(peer);<\/p>\n
\/\/ 1. \u63a5\u6536\u6d88\u606f
\n ssize_t s = recvfrom(_sockfd, buffer, sizeof(buffer) – 1, 0,
\n (struct sockaddr*)&peer, &len);
\n if (s > 0) {
\n buffer[s] = 0; \/\/ \u624b\u52a8\u8865\u5145\u5b57\u7b26\u4e32\u7ed3\u5c3e\u7b26
\n std::string request = buffer;<\/p>\n
\/\/ 2. \u8f6f\u4ef6\u5206\u5c42：\u4ea4\u7ed9\u4e0a\u5c42\u4e1a\u52a1\u56de\u8c03\u5904\u7406
\n std::string response = _func(request);<\/p>\n
\/\/ 3. \u53d1\u9001\u54cd\u5e94\u7ed3\u679c\u7ed9\u5ba2\u6237\u7aef
\n sendto(_sockfd, response.c_str(), response.size(), 0,
\n (struct sockaddr*)&peer, len);
\n }
\n }
\n }<\/p>\n
private:
\n int _sockfd;
\n uint16_t _port;
\n bool _isrunning;
\n func_t _func; \/\/ \u4e0a\u5c42\u56de\u8c03\u51fd\u6570
\n}; <\/p>\n
\u5904\u7406IP\u5730\u5740\u7684\u5b57\u7b26\u4e32\u683c\u5f0f（\u70b9\u5206\u5341\u8fdb\u5236，\u5982"192.168.1.1"）\u548c\u7f51\u7edc\u5b57\u8282\u5e8f\u4e8c\u8fdb\u5236\u6574\u6570（in_addr_t）\u4e4b\u95f4\u7684\u8f6c\u6362\u65f6，Linux C API\u7ecf\u5386\u4e86\u4e00\u8f6e\u4ece\u4f20\u7edf\u65e7API\u5230\u73b0\u4ee3\u5316POSIX API\u7684\u6f14\u8fdb\u3002<\/p>\n
[\u5b57\u7b26\u4e32 IP "192.168.1.1"] \u00a0\u2500\u2500inet_pton \/ inet_addr\u2500\u2500> \u00a0[\u7f51\u7edc\u5b57\u8282\u5e8f 32 \u4f4d\u6574\u6570] [\u5b57\u7b26\u4e32 IP "192.168.1.1"] \u00a0<\u2500\u2500inet_ntop \/ inet_ntoa\u2500\u2500 \u00a0[\u7f51\u7edc\u5b57\u8282\u5e8f 32 \u4f4d\u6574\u6570]<\/p>\n
\u2460inet_addr<\/p>\n
\u529f\u80fd：\u628a\u70b9\u5206\u5341\u8fdb\u5236\u5b57\u7b26\u4e32\u8f6c\u6210in_addr_t\u3002<\/p>\n<\/li>\n
\u5c40\u9650：\u53ea\u8ba4IPv4；\u78b0\u4e0a\u5e7f\u64ad\u5730\u5740255.255.255.255，\u5b83\u8fd4\u56de-1（\u5373INADDR_NONE），\u8fd9\u5c31\u6709\u4e86\u6b67\u4e49\u2014\u2014\u5230\u5e95\u662f\u5730\u5740\u65e0\u6548，\u8fd8\u662f\u771f\u5c31\u662f\u4e2a\u5e7f\u64ad\u5730\u5740？\u5206\u4e0d\u6e05，\u9519\u8bef\u5904\u7406\u4e5f\u96be\u505a\u3002<\/p>\n<\/li>\n<\/ul>\n
\u2461 inet_ntoa\u4e0e\u7ebf\u7a0b\u5b89\u5168\u9690\u60a3<\/p>\n
\u529f\u80fd：\u628a4\u5b57\u8282\u7f51\u7edc\u5b57\u8282\u5e8fIP\u8f6c\u6210\u70b9\u5206\u5341\u8fdb\u5236\u5b57\u7b26\u4e32\u3002<\/p>\n<\/li>\n
\u81f4\u547d\u7f3a\u9677（\u7ebf\u7a0b\u4e0d\u5b89\u5168）：inet_ntoa\u5185\u90e8\u7528\u4e86\u4e00\u4e2a\u9759\u6001\u5c40\u90e8\u7f13\u51b2\u533a（static buffer）\u6765\u5b58\u8f6c\u6362\u540e\u7684\u5b57\u7b26\u4e32\u3002\u591a\u7ebf\u7a0b\u5e76\u53d1\u73af\u5883\u4e0b，\u5982\u679c\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8c03inet_ntoa，\u540e\u9762\u7684\u7ebf\u7a0b\u4f1a\u628a\u524d\u9762\u7ebf\u7a0b\u7f13\u5b58\u5728\u9759\u6001\u533a\u91cc\u7684IP\u5b57\u7b26\u4e32\u8986\u76d6\u6389，\u5f15\u53d1\u4e25\u91cd\u7684\u5e76\u53d1\u6570\u636e\u7ade\u4e89\u3002<\/p>\n<\/li>\n<\/ul>\n
\u73b0\u4ee3\u7f51\u7edc\u7f16\u7a0b，\u63a8\u8350\u7528inet_pton（Presentation to Network）\u548cinet_ntop（Network to Presentation）\u3002<\/p>\n
API\u63a5\u53e3\u58f0\u660e：<\/p>\n
#include <arpa\/inet.h><\/p>\n
\/\/ \u5b57\u7b26\u4e32 IP -> \u4e8c\u8fdb\u5236\u7f51\u7edc\u5b57\u8282\u5e8f IP
\nint inet_pton(int af, const char *src, void *dst);<\/p>\n
\/\/ \u4e8c\u8fdb\u5236\u7f51\u7edc\u5b57\u8282\u5e8f IP -> \u5b57\u7b26\u4e32 IP
\nconst char *inet_ntop(int af, const void *src, char *dst, socklen_t size); <\/p>\n
\u4e24\u5927\u6838\u5fc3\u4f18\u52bf：<\/p>\n
\u652f\u6301\u534f\u8bae\u65cf：\u7b2c\u4e00\u4e2a\u53c2\u6570af\u53ef\u4ee5\u663e\u5f0f\u6307\u5b9aAF_INET（IPv4）\u6216AF_INET6（IPv6），\u6269\u5c55\u6027\u62c9\u6ee1\u3002<\/p>\n<\/li>\n
\u7edd\u5bf9\u7ebf\u7a0b\u5b89\u5168：inet_ntop\u8981\u6c42\u8c03\u7528\u8005\u663e\u5f0f\u4f20\u5165\u4e00\u4e2a\u7531\u8c03\u7528\u65b9\u7ef4\u62a4\u7684\u5185\u5b58\u7f13\u51b2\u533a\u6307\u9488（\u6bd4\u5982\u6808\u4e0a\u5206\u914d\u7684char ipbuffer[64]）\u3002\u5b83\u4e0d\u4f9d\u8d56\u5185\u90e8\u9759\u6001\u7f13\u51b2\u533a，\u6bcf\u4e2a\u7ebf\u7a0b\u5728\u81ea\u5df1\u7684\u6808\u5e27\u7a7a\u95f4\u91cc\u64cd\u4f5c，\u7ebf\u7a0b\u5b89\u5168\u9690\u60a3\u4ece\u6839\u4e0a\u88ab\u6d88\u9664\u3002<\/p>\n<\/li>\n<\/ul>\n
\u5c01\u88c5\u73b0\u4ee3 IP \u5730\u5740\u8f6c\u6362\u7c7b\u793a\u4f8b：<\/p>\n
#include <arpa\/inet.h>
\n#include <string>
\n#include <cstring><\/p>\n
class InetAddr {
\npublic:
\n \/\/ \u4ece sockaddr_in \u7ed3\u6784\u63d0\u53d6 IP \u548c\u7aef\u53e3
\n InetAddr(const struct sockaddr_in &addr) : _addr(addr) {
\n _port = ntohs(_addr.sin_port);<\/p>\n
\/\/ \u663e\u5f0f\u5728\u6808\u4e0a\u521b\u5efa\u7f13\u51b2\u533a，\u4f7f\u7528\u7ebf\u7a0b\u5b89\u5168\u7684 inet_ntop
\n char ipbuffer[64];
\n inet_ntop(AF_INET, &_addr.sin_addr, ipbuffer, sizeof(ipbuffer));
\n _ip = ipbuffer;
\n }<\/p>\n
\/\/ \u4ece IP \u548c Port \u6784\u5efa sockaddr_in \u7ed3\u6784
\n InetAddr(const std::string &ip, uint16_t port) : _ip(ip), _port(port) {
\n memset(&_addr, 0, sizeof(_addr));
\n _addr.sin_family = AF_INET;
\n _addr.sin_port = htons(_port);<\/p>\n
\/\/ \u4f7f\u7528\u7ebf\u7a0b\u5b89\u5168\u7684 inet_pton
\n inet_pton(AF_INET, _ip.c_str(), &_addr.sin_addr);
\n }<\/p>\n
std::string Ip() const { return _ip; }
\n uint16_t Port() const { return _port; }
\n struct sockaddr_in GetAddr() const { return _addr; }<\/p>\n
private:
\n struct sockaddr_in _addr;
\n std::string _ip;
\n uint16_t _port;
\n}; <\/p>\n
\u7528inet_pton\u548cinet_ntop\u642d\u914d\u6808\u7f13\u51b2\u533a\u6216\u8005\u5c01\u88c5\u7c7b，\u65e2\u5b8c\u7f8e\u652f\u6301IPv4\/IPv6\u6269\u5c55，\u53c8\u80fd\u786e\u4fdd\u591a\u7ebf\u7a0b\u9ad8\u5e76\u53d1\u5e94\u7528\u4e0b\u7684\u7edd\u5bf9\u5b89\u5168\u3002\u65e7API\u90a3\u70b9\u5751，\u5230\u6b64\u5c31\u7b97\u5f7b\u5e95\u7ed5\u8fc7\u53bb\u4e86\u3002<\/p>\n
\u4e0b\u9762\u628a\u6574\u5957UDP\u670d\u52a1\u5668\u4e0e\u5ba2\u6237\u7aef\u7684\u5b8c\u6574\u4ee3\u7801\u6574\u7406\u51fa\u6765，\u5305\u542bIP\u5730\u5740\u5c01\u88c5\u7c7b\u3001UDP\u670d\u52a1\u5668\u7c7b\u3001\u670d\u52a1\u7aef\u4e3b\u7a0b\u5e8f\u3001\u5ba2\u6237\u7aef\u4e3b\u7a0b\u5e8f，\u4ee5\u53caMakefile\u3002\u4ee3\u7801\u53ef\u76f4\u63a5\u7f16\u8bd1\u8fd0\u884c\u3002<\/p>\n
#pragma once<\/p>\n
#include <arpa\/inet.h>
\n#include <string>
\n#include <cstring>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h><\/p>\n
namespace NetModule
\n{
\n class InetAddr
\n {
\n public:
\n \/\/ \u4ece sockaddr_in \u7ed3\u6784\u63d0\u53d6 IP \u548c\u7aef\u53e3（\u7528\u4e8e\u670d\u52a1\u7aef\u63a5\u6536\u5ba2\u6237\u7aef\u5730\u5740）
\n InetAddr(const struct sockaddr_in &addr)
\n : _addr(addr)
\n {
\n _port = ntohs(_addr.sin_port);<\/p>\n
\/\/ \u663e\u5f0f\u5728\u6808\u4e0a\u521b\u5efa\u7f13\u51b2\u533a，\u4f7f\u7528\u7ebf\u7a0b\u5b89\u5168\u7684 inet_ntop
\n char ipbuffer[64];
\n inet_ntop(AF_INET, &_addr.sin_addr, ipbuffer, sizeof(ipbuffer));
\n _ip = ipbuffer;
\n }<\/p>\n
\/\/ \u4ece IP \u548c Port \u6784\u5efa sockaddr_in \u7ed3\u6784（\u7528\u4e8e\u5ba2\u6237\u7aef\u6307\u5b9a\u670d\u52a1\u7aef\u5730\u5740）
\n InetAddr(const std::string &ip, uint16_t port)
\n : _ip(ip), _port(port)
\n {
\n memset(&_addr, 0, sizeof(_addr));
\n _addr.sin_family = AF_INET;
\n _addr.sin_port = htons(_port);<\/p>\n
\/\/ \u4f7f\u7528\u7ebf\u7a0b\u5b89\u5168\u7684 inet_pton
\n inet_pton(AF_INET, _ip.c_str(), &_addr.sin_addr);
\n }<\/p>\n
std::string Ip() const { return _ip; }
\n uint16_t Port() const { return _port; }
\n struct sockaddr_in GetAddr() const { return _addr; }<\/p>\n
~InetAddr() {}<\/p>\n
private:
\n struct sockaddr_in _addr;
\n std::string _ip;
\n uint16_t _port;
\n };
\n} <\/p>\n
#pragma once<\/p>\n
#include <iostream>
\n#include <string>
\n#include <functional>
\n#include <cstring>
\n#include <cstdlib>
\n#include <unistd.h>
\n#include <sys\/types.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h><\/p>\n
#include "InetAddr.hpp"<\/p>\n
namespace NetModule
\n{
\n \/\/ \u4e1a\u52a1\u5904\u7406\u51fd\u6570\u7c7b\u578b：\u8f93\u5165\u8bf7\u6c42\u5b57\u7b26\u4e32，\u8fd4\u56de\u54cd\u5e94\u5b57\u7b26\u4e32
\n using func_t = std::function<std::string(const std::string &)>;<\/p>\n
const uint16_t DEFAULT_PORT = 8080;
\n const int BACKLOG = 10;<\/p>\n
class UdpServer
\n {
\n public:
\n UdpServer(uint16_t port = DEFAULT_PORT, func_t func = nullptr)
\n : _port(port), _func(func), _isrunning(false), _sockfd(-1)
\n {
\n }<\/p>\n
\/\/ \u521d\u59cb\u5316：\u521b\u5efa\u5957\u63a5\u5b57 + \u7ed1\u5b9a\u5730\u5740
\n void Init()
\n {
\n \/\/ 1. \u521b\u5efa UDP \u5957\u63a5\u5b57
\n _sockfd = socket(AF_INET, SOCK_DGRAM, 0);
\n if (_sockfd < 0)
\n {
\n std::cerr << "socket error" << std::endl;
\n exit(1);
\n }
\n std::cout << "socket create success, sockfd: " << _sockfd << std::endl;<\/p>\n
\/\/ 2. \u586b\u5145\u672c\u5730\u5730\u5740\u7ed3\u6784\u4f53
\n struct sockaddr_in local;
\n memset(&local, 0, sizeof(local));
\n local.sin_family = AF_INET;
\n local.sin_port = htons(_port);
\n local.sin_addr.s_addr = INADDR_ANY; \/\/ \u76d1\u542c\u6240\u6709\u7f51\u5361<\/p>\n
\/\/ 3. \u7ed1\u5b9a\u5730\u5740
\n int n = bind(_sockfd, (struct sockaddr *)&local, sizeof(local));
\n if (n < 0)
\n {
\n std::cerr << "bind error" << std::endl;
\n exit(2);
\n }
\n std::cout << "bind success, port: " << _port << std::endl;
\n }<\/p>\n
\/\/ \u542f\u52a8\u670d\u52a1\u5668：\u6b7b\u5faa\u73af\u63a5\u6536 + \u5904\u7406 + \u54cd\u5e94
\n void Start()
\n {
\n _isrunning = true;
\n char buffer[1024];<\/p>\n
while (_isrunning)
\n {
\n struct sockaddr_in peer;
\n socklen_t len = sizeof(peer);<\/p>\n
\/\/ 1. \u63a5\u6536\u6d88\u606f
\n ssize_t s = recvfrom(_sockfd, buffer, sizeof(buffer) – 1, 0,
\n (struct sockaddr *)&peer, &len);
\n if (s < 0)
\n {
\n std::cerr << "recvfrom error" << std::endl;
\n continue;
\n }<\/p>\n
buffer[s] = 0; \/\/ \u624b\u52a8\u8865\u5145\u5b57\u7b26\u4e32\u7ed3\u5c3e\u7b26
\n std::string request = buffer;<\/p>\n
\/\/ \u6784\u9020\u5bf9\u7aef\u5730\u5740\u5bf9\u8c61，\u65b9\u4fbf\u6253\u5370\u548c\u540e\u7eed\u4f7f\u7528
\n InetAddr peerAddr(peer);
\n std::cout << "[" << peerAddr.Ip() << ":" << peerAddr.Port() << "]# "
\n << request << std::endl;<\/p>\n
\/\/ 2. \u8f6f\u4ef6\u5206\u5c42：\u4ea4\u7ed9\u4e0a\u5c42\u4e1a\u52a1\u56de\u8c03\u5904\u7406
\n std::string response;
\n if (_func)
\n {
\n response = _func(request);
\n }
\n else
\n {
\n response = "Server received: " + request;
\n }<\/p>\n
\/\/ 3. \u53d1\u9001\u54cd\u5e94\u7ed3\u679c\u7ed9\u5ba2\u6237\u7aef
\n sendto(_sockfd, response.c_str(), response.size(), 0,
\n (struct sockaddr *)&peer, len);
\n }
\n }<\/p>\n
~UdpServer()
\n {
\n if (_sockfd >= 0)
\n {
\n close(_sockfd);
\n }
\n }<\/p>\n
private:
\n int _sockfd;
\n uint16_t _port;
\n bool _isrunning;
\n func_t _func; \/\/ \u4e0a\u5c42\u56de\u8c03\u51fd\u6570
\n };
\n} <\/p>\n
#include "UdpServer.hpp"
\n#include <memory><\/p>\n
\/\/ \u4e1a\u52a1\u5904\u7406\u56de\u8c03：\u628a\u6536\u5230\u7684\u5b57\u7b26\u4e32\u8f6c\u6210\u5927\u5199\u518d\u8fd4\u56de
\nstd::string Handler(const std::string &request)
\n{
\n std::string response = request;
\n for (auto &ch : response)
\n {
\n if (ch >= 'a' && ch <= 'z')
\n {
\n ch -= 32;
\n }
\n }
\n return response;
\n}<\/p>\n
\/\/ \u7528\u6cd5：.\/udp_server [\u7aef\u53e3\u53f7]
\nint main(int argc, char *argv[])
\n{
\n uint16_t port = NetModule::DEFAULT_PORT;<\/p>\n
if (argc == 2)
\n {
\n port = static_cast<uint16_t>(std::stoi(argv[1]));
\n }<\/p>\n
std::unique_ptr<NetModule::UdpServer> server =
\n std::make_unique<NetModule::UdpServer>(port, Handler);<\/p>\n
server->Init();
\n server->Start();<\/p>\n
return 0;
\n} <\/p>\n
#include <iostream>
\n#include <string>
\n#include <cstring>
\n#include <cstdlib>
\n#include <unistd.h>
\n#include <sys\/types.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h><\/p>\n
\/\/ \u7528\u6cd5：.\/udp_client [\u670d\u52a1\u7aefIP] [\u670d\u52a1\u7aef\u7aef\u53e3]
\nint main(int argc, char *argv[])
\n{
\n if (argc != 3)
\n {
\n std::cerr << "Usage: " << argv[0] << " server_ip server_port" << std::endl;
\n return 1;
\n }<\/p>\n
std::string server_ip = argv[1];
\n uint16_t server_port = static_cast<uint16_t>(std::stoi(argv[2]));<\/p>\n
\/\/ 1. \u521b\u5efa UDP \u5957\u63a5\u5b57（\u5ba2\u6237\u7aef\u4e0d\u9700\u8981\u663e\u5f0f bind，\u7531\u5185\u6838\u9690\u5f0f\u5b8c\u6210）
\n int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
\n if (sockfd < 0)
\n {
\n std::cerr << "socket error" << std::endl;
\n return 2;
\n }<\/p>\n
\/\/ 2. \u586b\u5145\u670d\u52a1\u7aef\u5730\u5740\u7ed3\u6784\u4f53
\n struct sockaddr_in server;
\n memset(&server, 0, sizeof(server));
\n server.sin_family = AF_INET;
\n server.sin_port = htons(server_port);
\n inet_pton(AF_INET, server_ip.c_str(), &server.sin_addr);<\/p>\n
\/\/ 3. \u5faa\u73af\u53d1\u9001 + \u63a5\u6536
\n while (true)
\n {
\n std::string line;
\n std::cout << "Please Enter# ";
\n std::getline(std::cin, line);<\/p>\n
if (line == "quit" || line == "exit")
\n {
\n break;
\n }<\/p>\n
\/\/ \u53d1\u9001\u6570\u636e\u7ed9\u670d\u52a1\u7aef
\n sendto(sockfd, line.c_str(), line.size(), 0,
\n (struct sockaddr *)&server, sizeof(server));<\/p>\n
\/\/ \u63a5\u6536\u670d\u52a1\u7aef\u54cd\u5e94
\n char buffer[1024];
\n struct sockaddr_in peer;
\n socklen_t len = sizeof(peer);<\/p>\n
ssize_t s = recvfrom(sockfd, buffer, sizeof(buffer) – 1, 0,
\n (struct sockaddr *)&peer, &len);
\n if (s > 0)
\n {
\n buffer[s] = 0;
\n std::cout << "Server Response# " << buffer << std::endl;
\n }
\n }<\/p>\n
close(sockfd);
\n return 0;
\n} <\/p>\n
.PHONY: all
\nall: udp_server udp_client<\/p>\n
udp_server: UdpServer.cc UdpServer.hpp InetAddr.hpp
\ng++ -o $@ $< -std=c++17<\/p>\n
udp_client: UdpClient.cc
\ng++ -o $@ $< -std=c++17<\/p>\n
.PHONY: clean
\nclean:
\nrm -f udp_server udp_client <\/p>\n
\u7f16\u8bd1：<\/p>\n
make <\/p>\n
\u5148\u542f\u52a8\u670d\u52a1\u7aef（\u9ed8\u8ba4\u7aef\u53e38080）：<\/p>\n
.\/udp_server <\/p>\n
\u6216\u8005\u6307\u5b9a\u7aef\u53e3：<\/p>\n
.\/udp_server 9090 <\/p>\n
\u518d\u542f\u52a8\u5ba2\u6237\u7aef，\u6307\u5b9a\u670d\u52a1\u7aefIP\u548c\u7aef\u53e3：<\/p>\n
.\/udp_client 127.0.0.1 8080 <\/p>\n
\u5ba2\u6237\u7aef\u8f93\u5165\u5185\u5bb9，\u670d\u52a1\u7aef\u4f1a\u6536\u5230\u5e76\u6253\u5370\u51fa\u6765，\u540c\u65f6\u628a\u5b57\u7b26\u4e32\u8f6c\u6210\u5927\u5199\u8fd4\u56de\u7ed9\u5ba2\u6237\u7aef\u3002\u8f93\u5165quit\u6216exit\u9000\u51fa\u5ba2\u6237\u7aef\u3002<\/p>\n
\u5982\u679c\u8fd9\u7bc7\u6587\u7ae0\u5bf9\u4f60\u6709\u5e2e\u52a9，\u522b\u5fd8\u4e86\u70b9\u8d5e\u3001\u6536\u85cf\u3001\u5173\u6ce8\u4e09\u8fde\u652f\u6301\u3002\u4f60\u7684\u6bcf\u4e00\u6b21\u53cd\u9988，\u90fd\u662f\u6211\u7ee7\u7eed\u786c\u6838\u8f93\u51fa\u7684\u6700\u5927\u52a8\u529b\u3002\u6211\u4eec\u4e0b\u7bc7\u89c1\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
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