\u5728Linux\u7cfb\u7edf\u4e2d\uff0c\u5982\u679c\u6709\u591a\u5f20\u7f51\u5361\uff0c\u90a3\u4e48\u53ef\u4ee5\u5229\u7528\u8fd9\u4e9b\u7f51\u5361\u6765\u5b9e\u73b0\u5bf9\u7ec4\u64ad\u6570\u636e\u7684\u63a5\u6536\u3002\u7ec4\u64ad\uff08Multicast\uff09\u662f\u6307\u5c06\u6570\u636e\u5305\u540c\u65f6\u4f20\u8f93\u7ed9\u591a\u4e2a\u4e3b\u673a\u7684\u4e00\u79cd\u505a\u6cd5\uff0c\u4e0e\u5e7f\u64ad\uff08Broadcast\uff09\u548c\u5355\u64ad\uff08Unicast\uff09\u4e0d\u540c\u3002<\/p>\n
\u5728\u591a\u7f51\u5361\u73af\u5883\u4e0b\uff0c\u6709\u591a\u79cd\u65b9\u5f0f\u53ef\u4ee5\u5b9e\u73b0\u5bf9\u7ec4\u64ad\u6570\u636e\u7684\u63a5\u6536\u3002\u4e0b\u9762\u6211\u4eec\u5c31\u6765\u8be6\u7ec6\u8bb2\u89e3\u4e00\u4e0b\u3002<\/p>\n
1. \u4f7f\u7528SO_REUSEADDR\u9009\u9879<\/p>\n
\u4f7f\u7528SO_REUSEADDR\u9009\u9879\u53ef\u4ee5\u8ba9\u540c\u4e00\u53f0\u4e3b\u673a\u4e0a\u7684\u591a\u4e2a\u7a0b\u5e8f\u53ef\u4ee5\u540c\u65f6\u7ed1\u5b9a\u5230\u76f8\u540c\u7684\u7ec4\u64ad\u5730\u5740\u548c\u7aef\u53e3\u3002<\/p>\n
\u5177\u4f53\u64cd\u4f5c\u6b65\u9aa4\u5982\u4e0b\uff1a<\/p>\n
\u4e4b\u4e00\u6b65\uff1a\u521b\u5efasocket\u5bf9\u8c61\u3002<\/p>\n
\u201c`c<\/p>\n
sockfd = socket(AF_INET, SOCK_DGRAM, 0);<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e8c\u6b65\uff1a\u8bbe\u7f6eSO_REUSEADDR\u9009\u9879\u3002<\/p>\n
\u201c`c<\/p>\n
int reuse = 1;<\/p>\n
setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *)&reuse, sizeof(int));<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e09\u6b65\uff1a\u7ed1\u5b9a\u7aef\u53e3\u548c\u7ec4\u64ad\u5730\u5740\u3002<\/p>\n
\u201c`c<\/p>\n
struct sockaddr_in groupaddr;<\/p>\n
memset(&groupaddr, 0, sizeof(groupaddr));<\/p>\n
groupaddr.sin_family = AF_INET;<\/p>\n
groupaddr.sin_addr.s_addr = inet_addr(\u201c224.0.0.1\u201d);<\/p>\n
groupaddr.sin_port = htons(8888);<\/p>\n
bind(sockfd, (struct sockaddr*)&groupaddr, sizeof(groupaddr));<\/p>\n
\u201c`<\/p>\n
2. \u4f7f\u7528IP_ADD_MEMBERSHIP\u9009\u9879<\/p>\n
\u4f7f\u7528IP_ADD_MEMBERSHIP\u9009\u9879\u53ef\u4ee5\u8ba9\u5355\u4e2a\u7a0b\u5e8f\u53ef\u4ee5\u540c\u65f6\u52a0\u5165\u591a\u4e2a\u7ec4\u64ad\u5730\u5740\u3002<\/p>\n
\u5177\u4f53\u64cd\u4f5c\u6b65\u9aa4\u5982\u4e0b\uff1a<\/p>\n
\u4e4b\u4e00\u6b65\uff1a\u521b\u5efasocket\u5bf9\u8c61\u3002<\/p>\n
\u201c`c<\/p>\n
sockfd = socket(AF_INET, SOCK_DGRAM, 0);<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e8c\u6b65\uff1a\u8bbe\u7f6eIP_ADD_MEMBERSHIP\u9009\u9879\u3002<\/p>\n
\u201c`c<\/p>\n
struct ip_mreq mreq;<\/p>\n
memset(&mreq, 0, sizeof(mreq));<\/p>\n
mreq.imr_multiaddr.s_addr = inet_addr(\u201c224.0.0.1\u201d);<\/p>\n
mreq.imr_interface.s_addr = inet_addr(\u201c192.168.1.100\u201d);<\/p>\n
setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq, sizeof(mreq));<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e09\u6b65\uff1a\u7ed1\u5b9a\u7aef\u53e3\u548c\u4efb\u610fIP\u5730\u5740\u3002<\/p>\n
\u201c`c<\/p>\n
struct sockaddr_in localaddr;<\/p>\n
memset(&localaddr, 0, sizeof(localaddr));<\/p>\n
localaddr.sin_family = AF_INET;<\/p>\n
localaddr.sin_addr.s_addr = htonl(INADDR_ANY); \/\/\u7ed1\u5b9a\u5230\u4efb\u610fIP\u5730\u5740<\/p>\n
localaddr.sin_port = htons(8888);<\/p>\n
bind(sockfd, (struct sockaddr*)&localaddr, sizeof(localaddr));<\/p>\n
\u201c`<\/p>\n
3. \u4f7f\u7528SO_BINDTODEVICE\u9009\u9879<\/p>\n
\u4f7f\u7528SO_BINDTODEVICE\u9009\u9879\u53ef\u4ee5\u8ba9\u7a0b\u5e8f\u6307\u5b9a\u4f7f\u7528\u54ea\u4e2a\u7f51\u5361\u63a5\u6536\u7ec4\u64ad\u6570\u636e\u3002<\/p>\n
\u5177\u4f53\u64cd\u4f5c\u6b65\u9aa4\u5982\u4e0b\uff1a<\/p>\n
\u4e4b\u4e00\u6b65\uff1a\u521b\u5efasocket\u5bf9\u8c61\u3002<\/p>\n
\u201c`c<\/p>\n
sockfd = socket(AF_INET, SOCK_DGRAM, 0);<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e8c\u6b65\uff1a\u8bbe\u7f6eSO_BINDTODEVICE\u9009\u9879\u3002<\/p>\n
\u201c`c<\/p>\n
setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, \u201ceth0\u201d, strlen(\u201ceth0\u201d) + 1);<\/p>\n
\u201c`<\/p>\n
\u7b2c\u4e09\u6b65\uff1a\u7ed1\u5b9a\u7aef\u53e3\u548c\u7ec4\u64ad\u5730\u5740\u3002<\/p>\n
\u201c`c<\/p>\n
struct sockaddr_in groupaddr;<\/p>\n
memset(&groupaddr, 0, sizeof(groupaddr));<\/p>\n
groupaddr.sin_family = AF_INET;<\/p>\n
groupaddr.sin_addr.s_addr = inet_addr(\u201c224.0.0.1\u201d);<\/p>\n
groupaddr.sin_port = htons(8888);<\/p>\n
bind(sockfd, (struct sockaddr*)&groupaddr, sizeof(groupaddr));<\/p>\n
\u201c`<\/p>\n
\u5728Linux\u4e0b\u591a\u7f51\u5361\u5982\u4f55\u5b9e\u73b0\u7ec4\u64ad\u63a5\u6536\uff0c\u53ef\u4ee5\u91c7\u7528\u4ee5\u4e0a\u4e09\u79cd\u65b9\u5f0f\uff0c\u5177\u4f53\u5e94\u6839\u636e\u5b9e\u9645\u9700\u6c42\u548c\u7f51\u5361\u8bbe\u7f6e\u6765\u9009\u62e9\u76f8\u5e94\u7684\u65b9\u6cd5\u3002SO_REUSEADDR\u9009\u9879\u9002\u5408\u540c\u4e00\u53f0\u4e3b\u673a\u4e0a\u7684\u591a\u4e2a\u7a0b\u5e8f\u5171\u4eab\u7ec4\u64ad\u5730\u5740\u548c\u7aef\u53e3\uff1bIP_ADD_MEMBERSHIP\u9009\u9879\u9002\u5408\u5355\u4e2a\u7a0b\u5e8f\u52a0\u5165\u591a\u4e2a\u7ec4\u64ad\u5730\u5740\uff1bSO_BINDTODEVICE\u9009\u9879\u53ef\u4ee5\u6307\u5b9a\u7a0b\u5e8f\u4f7f\u7528\u54ea\u4e2a\u7f51\u5361\u63a5\u6536\u7ec4\u64ad\u6570\u636e\u3002<\/p>\n
\u76f8\u5173\u95ee\u9898\u62d3\u5c55\u9605\u8bfb\uff1a<\/strong><\/p>\n \u5e94\u7528\u7a0b\u5e8f<\/p>\n \u901a\u8fc7\u547d\u4ee4\u5b57IP_ADD_MEMBERSHIP\u628a\u4e00\u4e2asocket\u52a0\u5165\u5230\u4e00\u4e2a\u591a\u64ad\u7ec4\uff0cIP_ADD_MEMBERSHIP\u662f\u4e00\u4e2aIP\u5c42\u7684\u547d\u4ee4\u5b57\uff0c\u5176\u8c03\u7528\u4f7f\u7528\u7684\u53c2\u6570\u662f<\/p>\n \u7ed3\u6784\u4f53<\/p>\n struct ip_mreq\uff0c\u5176\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n struct ip_mreq<\/p>\n {<\/p>\n struct in_addr imr_multiaddr;<\/p>\n struct in_addr imr_interface;<\/p>\n };<\/p>\n \u8be5\u7ed3\u6784\u4f53\u7684\u4e24\u4e2a\u6210\u5458\u5206\u522b\u7528\u4e8e\u6307\u5b9a\u6240\u52a0\u5165\u7684\u591a\u64ad\u7ec4\u7684\u7ec4<\/p>\n IP\u5730\u5740<\/p>\n \uff0c\u548c\u6240\u8981\u52a0\u5165\u7ec4\u7684\u90a3\u4e2a\u672c\u5730\u63a5\u53e3\u7684IP\u5730\u5740\u3002\u8be5\u547d\u4ee4\u5b57\u6ca1\u6709<\/p>\n \u6e90<\/p>\n \u8fc7\u6ee4\u7684\u529f\u80fd\uff0c\u5b83\u76f8\u5f53\u4e8e\u5b9e\u73b0IGMPv1\u7684\u591a\u64ad\u52a0\u5165\u670d\u52a1\u63a5\u53e3\u3002<\/p>\n ip_setsockopt\u5b9e\u73b0\u4e86\u8be5\u547d\u4ee4\u5b57\uff0c\u5b83\u6865\u77e5\u901a\u8fc7\u8c03\u7528ip_mc_join_group\u628asocket\u52a0\u5165\u5230\u591a\u64ad\u7ec4\u3002<\/p>\n \u8868\u793asocket\u7684\u7ed3\u6784\u4f53struct inet_sock\u6709\u4e00\u4e2a\u6210\u5458mc_list\uff0c\u5b83\u662f\u4e00\u4e2a\u7ed3\u6784\u4f53struct ip_mc_socklist\u7684\u6307\u9488\uff0c\u5b9e\u9645\u4e0a\u4e00\u4e2a\u8be5\u7ed3\u6784\u4f53\u7684<\/p>\n \u94fe\u8868<\/p>\n \uff0c\u8be5\u7ed3\u6784\u4f53\u7684\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n struct ip_mc_socklist<\/p>\n {<\/p>\n struct ip_mc_socklist *next;<\/p>\n struct ip_mreqnmulti;<\/p>\n<\/p>\n unsigned int<\/p>\n sfmode;<\/p>\n struct ip_sf_socklist *sflist;<\/p>\n };<\/p>\n next\u6307\u5411\u94fe\u8868\u7684\u4e0b\u4e00\u4e2a\u8282\u70b9\uff1bmulti\u8868\u793a\u7ec4\u4fe1\u606f\uff0c\u5373\u5728\u54ea\u4e00\u4e2a\u672c\u5730\u63a5\u53e3\u4e0a\uff0c\u52a0\u5165\u5230\u54ea\u4e00\u4e2a\u591a\u64ad\u7ec4\uff1bsfmode\u662f\u8fc7\u6ee4\u6a21\u5f0f\uff0c\u53d6\u503c\u4e3a<\/p>\n MCAST_INCLUDE\u6216MCAST_EXCLUDE\uff0c\u5206\u522b\u8868\u793a\u53ea\u63a5\u6536sflist\u6240\u5217\u51fa\u7684\u90a3\u4e9b\u6e90\u7684\u591a\u64ad\u6570\u636e\u62a5\uff0c\u548c\u4e0d\u63a5\u6536sflist\u6240\u5217\u51fa\u7684\u90a3\u4e9b\u6e90<\/p>\n \u7684\u591a\u64ad\u6570\u636e\u62a5\uff1bsflist\u662f\u6e90\u5217\u8868\uff0c\u7ed3\u6784\u4f53struct ip_sf_socklist\u7684\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n struct ip_sf_socklist<\/p>\n {<\/p>\n unsigned int sl_max;<\/p>\n unsigned int sl_count;<\/p>\n __usl_addr;<\/p>\n<\/p>\n };<\/p>\n sl_addr\u662f\u6e90\u5730\u5740\u5217\u8868\uff0csl_count\u5e94\u8be5\u662f\u6e90\u5730\u5740\u5217\u8868\u4e2d\u6e90\u5730\u5740\u7684\u6570\u91cf\uff0csl_max\u5e94\u8be5\u662f\u5f53\u524dsl_addr\u6570\u7ec4\u7684\u66f4\u5927\u53ef\u5bb9\u7eb3\u91cf(\u4e0d\u786e\u5b9a)\u3002\u5bf9<\/p>\n \u4e8e\u901a\u8fc7\u8c03\u7528IP_ADD_MEMBERSHIP\u52a0\u5165\u7684\u591a\u64ad\u7ec4\uff0c\u5b83\u4f1a\u5728struct inet_sock\u7684mc_list\u7684\u94fe<\/p>\n \u8868\u5934<\/p>\n \u6dfb\u52a0\u6a58\u71c3\u5982\u4e0b\u4e00\u4e2a\u8282\u70b9\uff1a<\/p>\n struct ip_mc_socklist{<\/p>\n .next = \u539f\u6765\u7684\u94fe\u8868\u5934;<\/p>\n .multi = \u6240\u52a0\u5165\u7684\u591a\u64ad\u7ec4\uff0c\u548c\u63a5\u53e3\u4fe1\u606f;<\/p>\n .sfmode = MCAST_EXCLUDE;<\/p>\n .sflist = NULL;\u5373\u4e0d\u6392\u9664\u4efb\u4f55\u6e90\u5730\u5740\uff0c\u4e5f\u5c31\u662f\u4e0d\u5b58\u5728\u6e90\u8fc7\u6ee4\u3002<\/p>\n }<\/p>\n \u53e6\u5916\uff0c\u4e00\u4e2asocket\u6240\u5141\u8bb8\u52a0\u5165\u7684\u591a\u64ad\u7ec4\u7684\u66f4\u5927\u6570\u91cf\u4e5f\u662f\u6709\u9650\u5236\u7684\uff0cmc_list\u4e2d\u8282\u70b9\u7684\u6570\u91cf\u4e0d\u5141\u8bb8\u8d85\u8fc7sysctl_igmp_max_memberships(\u7f3a\u7701\u4e3a20)\u3002<\/p>\n ip_mc_join_group\u8fd8\u9700\u8981\u901a\u8fc7ip_mreq.imr_interface\u7684\u6307\u5b9a\u503c\u627e\u5230\u8981\u52a0\u5165\u591a\u64ad\u7ec4\u7684\u90a3\u4e2a\u63a5\u53e3\uff0c\u5e76\u4e3a\u63a5\u53e3\u8bbe\u7f6e\u72b6\u6001(\u5373\u8be5\u63a5<\/p>\n \u53e3\u8981\u52a0\u5165\u54ea\u4e2a\u591a\u64ad\u7ec4\uff0c\u8fc7\u6ee4\u54ea\u4e9b\u6e90\uff0c\u4e5f\u5c31\u662f\u4e3a\u8be5\u63a5\u53e3\u589e\u52a0\u4e00\u4e2a\u7ec4\uff0c\u5982\u679c\u8981\u589e\u52a0\u7684\u7ec4\u5df2\u5b58\u5728\uff0c\u5219\u589e\u52a0\u8be5\u7ec4\u7684\u5f15\u7528\u8ba1\u6570)\u3002\u4ee3\u8868\u7f51\u7edc\u8bbe\u5907\u63a5\u53e3\u654f\u4f0d\u6d88\u7684\u7ed3\u6784\u4f53struct <\/p>\n in_device\u6709\u4e00\u4e2a\u6210\u5458mc_list\uff0c\u8fd9\u662f\u4e00\u4e2a\u7ed3\u6784\u4f53struct ip_mc_list\u7684\u94fe\u8868\uff0c\u8be5\u7ed3\u6784\u4f53\u7684\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n struct ip_mc_list<\/p>\n {<\/p>\n struct in_device *interface;<\/p>\n unsigned longmultiaddr;<\/p>\n struct ip_sf_list *sources;<\/p>\n struct ip_sf_list *tomb;<\/p>\n unsigned intsfmode;<\/p>\n unsigned longsfcount;<\/p>\n<\/p>\n struct ip_mc_list *next;<\/p>\n struct timer_list timer;<\/p>\n int users;<\/p>\n atomic_trefcnt;<\/p>\n spinlock_tlock;<\/p>\n char tm_running;<\/p>\n char reporter;<\/p>\n char unsolicit_count;<\/p>\n char loaded;<\/p>\n unsigned chargsquery;<\/p>\n unsigned charcrcount;<\/p>\n };<\/p>\n interface\u6307\u5411\u7f51\u7edc\u8bbe\u5907\u63a5\u53e3\uff0cmulticast\u5373\u4e3a\u52a0\u5165\u7684\u7ec4\u7684\u591a\u64ad\u5730\u5740\uff0cusers\u8bb0\u5f55\u5f53\u524d\u6709\u51e0\u4e2asocket\u5728\u8be5\u63a5\u53e3\u4e0a\u52a0\u5165\u4e86\u8be5\u591a\u64ad\u7ec4\u3002<\/p>\n sfcount\u662f\u4e00\u4e2a\u6709\u4e24\u4e2a\u5143\u7d20\u7684\u6570\u7ec4\uff0c\u5206\u522b\u8bb0\u5f55\u5728\u8be5\u63a5\u53e3\u4e0a\u52a0\u5165\u591a\u64ad\u7ec4\u7684socket\u7684\u8fc7\u6ee4\u6a21\u5f0f\u4e3aEXCLUDE\u548cINCLUDE\u7684\u6570\u91cf\uff0csfmode\u4e3a<\/p>\n \u8be5\u63a5\u53e3\u672c\u8eab\u7684\u8fc7\u6ee4\u6a21\u5f0f\u3002sources\u4e3a\u6e90\u5730\u5740\u5217\u8868\uff0c\u8be5\u7ed3\u6784\u4f53\u5177\u4f53\u5185\u5bb9\u7a0d\u540e\u518d\u5206\u6790\u3002timer\u4e3a\u4e3b\u52a8\u62a5\u544a\u5b9a\u65f6\u5668\uff0c\u5f53\u4e00\u4e2a\u63a5\u53e3(\u6ce8\u610f\uff1a\u4e0d\u662fsocket)\u65b0<\/p>\n \u52a0\u5165\u5230\u4e00\u4e2a\u591a\u64ad\u7ec4\uff0c\u9700\u8981\u5411\u591a\u64ad\u8def\u7531\u5668\u53d1\u9001\u4e00\u4e2aigmp\u62a5\u544a\uff0c\u4ee5\u901a\u77e5\u591a\u64ad\u8def\u7531\u5668\u9700\u8981\u5411\u672c\u5730\u7f51\u7edc\u8f6c\u53d1\u8be5\u7ec4\u7684\u6570\u636e\u62a5\u3002tm_running\u662f\u4e00\u4e2a\u6807\u5fd7\uff0c\u5982\u679c<\/p>\n timer\u5f53\u524d\u6b63\u5728\u8fd0\u884c\uff0c\u5219\u7f6e1\uff0c\u5426\u5219\u7f6e0\u3002reporter\u4e5f\u662f\u4e00\u4e2a\u6807\u5fd7\uff0c\u5982\u679c\u5f53\u524d\u6b63\u8981\u5f00\u59cb\u53d1\u9001igmp\u62a5\u544a\uff0c\u5219\u7f6e\u8be5\u6807\u5fd7\u4e3a1\uff0c\u5426\u5219\u4e3a0\u3002<\/p>\n unsolicit_count\u662f\u5f53\u4e00\u4e2a\u63a5\u53e3\u65b0\u52a0\u5165\u5230\u4e00\u4e2a\u591a\u64ad\u7ec4\u65f6\uff0c\u53d1\u9001\u4e3b\u52a8\u62a5\u544a\u7684\u6b21\u6570\uff0c\u503c\u8d4b\u4e3a<\/p>\n IGMP_Unsolicited_Report_Count(\u7f3a\u7701\u503c\u4e3a2)\u3002loaded\u4e5f\u662f\u4e00\u4e2a\u6807\u5fd7\uff0c\u5f53\u8be5\u63a5\u53e3\u4e0a\u7684\u8be5\u591a\u64ad\u7ec4\u88ab\u52a0\u5165\u65f6\uff0c\u9700\u8981\u901a\u77e5\u786c\u4ef6\u8fc7<\/p>\n \u6ee4\u5668\uff0c\u901a\u77e5\u5b8c\u6210\u5373\u7f6e\u8be5\u6807\u5fd7\u4e3a1\uff0c\u5426\u5219\u4e3a0\u3002<\/p>\n \u8be5\u7ed3\u6784\u4f53\u6bd4\u8f83\u590d\u6742\uff0c\u5148\u770b\u901a\u8fc7IP_ADD_MEMBERSHIP\u547d\u4ee4\u5b57\u628a\u4e00\u4e2asocket\u52a0\u5165\u5230\u4e00\u4e2a\u65b0\u7684\u591a\u64ad\u7ec4\uff0c\u4f1a\u4f7fstruct in_device\u7684mc_list\u4e2d\u589e\u52a0\u4e00\u4e2a\u4ec0\u4e48\u6837\u7684\u8282\u70b9\u3002\u4e0b\u9762\u662f\u751f\u6210\u7684\u8282\u70b9\u7684\u60c5\u51b5\uff1a<\/p>\n struct ip_mc_list{<\/p>\n .interface = in_dev;<\/p>\n .multiaddr = \u591a\u64ad\u7ec4\u5730\u5740;<\/p>\n .source = NULL;\/\/\u6e90\u8fc7\u6ee4\u5217\u8868\u4e3a\u7a7a\u3002<\/p>\n .tomb = NULL;<\/p>\n .sfmode = MCAST_EXCLUDE; \/\/EXCLUDE\u6a21\u5f0f\uff0c\u5373\u4e0d\u8fc7\u6ee4\u4efb\u4f55\u6e90\u3002<\/p>\n .sfcount = 1;<\/p>\n<\/p>\n .sfcount = 0;\/\/\u5373\u8be5\u8282\u70b9\u4e0a\u8be5\u591a\u64ad\u7ec4\u6709\u4e00\u4e2asocket\u52a0\u5165\uff0c\u8fc7\u6ee4\u6a21\u5f0f\u4e3aEXCLUDE\u3002<\/p>\n<\/p>\n .users = 1; \/\/\u6709\u4e00\u4e2a\u7528\u6237\u3002<\/p>\n .refcnt = 1; \/\/\u5f15\u7528\u8ba1\u6570\u4e3a1<\/p>\n .tm_running = 0;<\/p>\n .unsolicit_count = 2;<\/p>\n \u2026 \u2026<\/p>\n }<\/p>\n \u65b0\u751f\u6210\u7684\u8282\u70b9\u52a0\u5165\u5230mc_list\u94fe\u8868\u4e2d\u540e\uff0c\u8981\u901a\u77e5\u7f51\u7edc\u8bbe\u5907\u63a5\u53e3\u7684\u786c\u4ef6\uff0c\u4ee5\u4f7f\u5b83\u7684\u8fc7\u6ee4\u673a\u5236\u53ef\u4ee5\u63a5\u6536\u8fdb\u8be5\u591a\u64ad\u7ec4\u7684\u6570\u636e\u62a5\uff0c\u540c\u65f6\u4e5f\u8981\u901a\u77e5\u591a\u64ad\u8def\u7531\u5668\u3002<\/p>\n \u9996\u5148\u8981\u628a\u591a\u64ad\u5730\u5740\u6620\u5c04\u6210<\/p>\n \u4ee5\u592a\u7f51<\/p>\n \u5730\u5740\uff0c\u6620\u5c04\u89c4\u5219\u662f\u628a\u591a\u64adIP\u5730\u5740\u7684\u4f4e23\u4f4d\u653e\u5230\u4ee5\u592a\u7f51\u591a\u64ad\u5730\u5740E(<\/p>\n 16\u8fdb\u5236<\/p>\n )\u7684\u4f4e23\u4f4d\u3002<\/p>\n \u56e0\u4e3a\u4e00\u4e2aIP\u7ec4\u5730\u5740\u670928\u4f4d\u6709\u6548\u4f4d(\u9664\u53bb\u9ad8\u4f4d\u76841110)\uff0c\u6240\u4ee5\u6709\u53ef\u80fd\u51fa\u73b0\u591a\u4e2a\u7ec4\u5730\u5740\u88ab\u6620\u5c04\u6210\u540c\u4e00\u4e2a\u4ee5\u592a\u7f51\u591a\u64ad\u5730\u5740\uff0c\u5177\u4f53\u5b9e\u73b0\u89c1<\/p>\n ip_eth_mc_map\u3002\u7136\u540e\u628a\u8fd9\u4e2amac\u5730\u5740\u52a0\u5230\u786c\u4ef6\u7684\u8fc7\u6ee4\u673a\u5236\u4e2d\u3002<\/p>\n \u5177\u4f53\u7684\u5b9e\u73b0\u5728\u51fd\u6570dev_mc_add\u4e2d\u3002\u4ee3\u8868\u7f51\u7edc\u8bbe\u5907\u63a5\u53e3\u7684\u7ed3\u6784\u4f53struct net_device\u4e5f\u6709\u4e00\u4e2a\u6210\u5458mc_list\uff0c\u5b83\u662f\u4e00\u4e2a\u7ed3\u6784\u4f53struct dev_mc_list\u7684\u94fe\u8868\uff0c\u8be5\u7ed3\u6784\u4f53\u7684\u5b9a\u4e49\u5982\u4e0b\uff1a<\/p>\n struct dev_mc_list<\/p>\n {<\/p>\n struct dev_mc_list *next;<\/p>\n __udmi_addr;<\/p>\n<\/p>\n unsigned char dmi_addrlen;<\/p>\n intdmi_users;<\/p>\n intdmi_gusers;<\/p>\n };<\/p>\n next\u6307\u5411\u94fe\u8868\u4e0b\u4e00\u4e2a\u8282\u70b9\uff0cdmi_addr\u662f\u591a\u64admac\u5730\u5740\uff0cdmi_addrlen\u4e3a\u591a\u64admac\u5730\u5740\u7684\u957f\u5ea6\uff0cdmi_users\u662f\u5728\u8282\u70b9\u88ab\u91cd\u590d\u5230\u52a0<\/p>\n \u5165\u5230\u8bbe\u5907\u4e0a\u7684\u6b21\u6570\uff0cstruct <\/p>\n net_device\u8fd8\u6709\u4e00\u4e2a\u6210\u5458mc_count\uff0c\u7528\u4e8e\u8bb0\u5f55\u94fe\u8868\u4e2d\u8282\u70b9\u7684\u6570\u91cf\u3002dev_mc_add\u521b\u5efa\u4e00\u4e2a\u65b0\u7684struct <\/p>\n dev_mc_list\u8282\u70b9\uff0c\u52a0\u5165\u5230\u94fe\u8868\u4e2d\uff0c\u5e76\u901a\u8fc7\u8c03\u7528\u7f51\u7edc\u8bbe\u5907\u63a5\u53e3\u7684\u6210\u5458\u51fd\u6570set_multicast_list\u6765\u542f\u7528\u8bbe\u5907\u7684\u8fc7\u6ee4\u673a\u5236\u3002<\/p>\n \u6700\u540e\u4e00\u6b65\u53d1\u9001\u4e3b\u52a8\u6210\u5458\u62a5\u544a\uff0c\u8fd9\u91cc\uff0c\u9996\u5148\u5ffd\u7565IGMPv1\u548cIGMPv2\u5b58\u5728\u7684\u60c5\u51b5\u3002\u5982\u679c\u8981\u52a0\u5165\u7684\u591a\u64ad\u7ec4\u662f<\/p>\n IGMP_ALL_HOSTS(224.0.0.1)\uff0c\u5219\u4e0d\u9700\u8981\u53d1\u9001\u6210\u5458\u62a5\u544a\u3002\u5426\u5219\u542f\u7528\u5b9a\u65f6\u5668struct <\/p>\n in_device->mr_ifc_timer(\u63a5\u53e3\u72b6\u6001\u6539\u53d8\u5b9a\u65f6\u5668)\uff0c\u8be5\u5b9a\u65f6\u5668\u5728\u8bbe\u5907\u521d\u59cb\u5316\u7684\u65f6\u5019\u88ab\u5efa\u7acb\uff0c\u5176\u8d85\u65f6\u5904\u7406\u51fd\u6570\u662f<\/p>\n igmp_ifc_timer_expire\uff0c\u5b83\u53d1\u9001\u4e00\u4e2aIGMPv3\u7684\u62a5\u544a\uff0c\u7136\u540e\u518d\u6b21\u542f\u7528\u5b9a\u65f6\u5668\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u4e4b\u4e00\u4e2a\u4e3b\u52a8\u6210\u5458\u62a5\u544a\u7acb\u5373\u53d1\u51fa\uff0c\u7136\u540e\u5728\u4e00\u4e2a0<\/p>\n \u5230IGMP_Unsolicited_Report_Interval(\u7f3a\u7701\u4e3a10\u79d2)\u4e4b\u95f4\u7684\u4e00\u4e2a\u65f6\u95f4\u540e\uff0c\u53d1\u51fa\u7b2c\u4e8c\u4e2a\u4e3b\u52a8\u6210\u5458\u62a5\u544a\uff0c\u8fde\u7eed\u53d1\u51fa<\/p>\n IGMP_Unsolicited_Report_Count(\u7f3a\u7701\u503c\u4e3a2)\u4e2a\u3002<\/p>\n \u6d4b\u8bd5\u73af\u5883\u4e2d\u8981\u52a0\u5165\u7684\u591a\u64ad\u7ec4\u662f224.0.1.1\uff0c\u53d1\u51fa\u7684IGMPv3\u62a5\u544a\u5982\u4e0b\uff1a<\/p>\n \u6570\u636e \u542b\u4e49<\/p>\n \u7b2c3\u7248\u6210\u5458\u5173\u7cfb\u62a5\u544a<\/p>\n bit\u4fdd\u7559\uff0c\u5fc5\u987b\u4e3a0<\/p>\n f8 fc \u6821\u9a8c\u548c<\/p>\n bit\u4fdd\u7559\uff0c\u5fc5\u987b\u4e3a0<\/p>\n \u7ec4\u8bb0\u5f55\u7684\u6570\u91cf\uff0c\u4e3a1<\/p>\n \u4e0b\u9762\u4e3a\u4e00\u6761\u7ec4\u8bb0\u5f55\uff1a<\/p>\n \u7c7b\u578b\u4e3aCHANGE_TO_EXCLUDE_MODE\uff0c\u6539\u53d8\u5230EXCLUDE\u8fc7\u6ee4\u6a21\u5f0f<\/p>\n \u8f85\u52a9\u6570\u636e\u957f\u5ea6<\/p>\n \u6e90\u5730\u5740\u7684\u6570\u91cf<\/p>\n socket\u521b\u5efaUDP\u901a\u4fe1\u63cf\u8ff0\u7b26\u540e\uff0csetsockopt\u52a0\u5165\u591a\u64ad\u7ec4\uff0c\u518dbind\u7ed1\u5b9a\u5230\u8be5\u7f51\u5361\u4e0a<\/p>\n \/\/\u5728\u6307\u5b9a\u7684IP\u548c\u7aef\u53e3\u4e0a\u63a5\u6536\u591a\u64ad\u7ec4\u7684\u62a5\u6587<\/p>\n int recv_msg(char *ip , unsigned short port \uff0c char *mult_ip )<\/p>\n {<\/p>\n \/\/\u5efa\u7acb\u901a\u8baf\u5957\u63a5\u5b57<\/p>\n int fd = socket( PF_INET , SOCK_DGRAM , 0 );<\/p>\n if( -1 == fd )<\/p>\n {<\/p>\n perror(\u201csocket failed\u201d);<\/p>\n return -1;<\/p>\n }<\/p>\n \/\/\u8bbe\u7f6e\u5730\u5740\u91cd\u7528\u548c\u63a5\u6536\u591a\u64ad<\/p>\n {<\/p>\n int reuse \u9646\u88ad= 1 ;<\/p>\n struct ip_mreqn mult_addr = {0};<\/p>\n mult_addr.imr_multiaddr.s_addr = inet_addr( mult_ip );<\/p>\n mult_addr.imr_address.s_addr = inet_addr( ip );<\/p>\n if( -1 == setsockopt( fd , IPPROTO_IP , IP_ADD_MEMBERSHIP ,<\/p>\n &mult_addr , sizeof(mult_addr)))<\/p>\n {<\/p>\n perror(\u201csetsockopt add failed\u201d);<\/p>\n goto _out;<\/p>\n }<\/p>\n if( -1 == setsockopt( fd , SOL_SOCKET, SO_REUSEADDR,<\/p>\n &reuse , sizeof(reuse) ) )<\/p>\n {<\/p>\n perror(\u201csetsockopt reuse failed\u201d);<\/p>\n }<\/p>\n }<\/p>\n \/\/\u7ed1\u5b9a\u5730\u5740\u548c\u7aef\u53e3<\/p>\n {<\/p>\n struct sockaddr_in addr = {0};<\/p>\n addr.sin_family = PF_INET;<\/p>\n addr.sin_port = htons( port );<\/p>\n addr.sin_addr.s_addr = INADDR_ANY;<\/p>\n if( -1 == bind( fd , (struct sockaddr*)&addr ,<\/p>\n sizeof(addr) ) )<\/p>\n {<\/p>\n perror(\u201cbind failed\u201d);<\/p>\n goto _out;<\/p>\n }<\/p>\n }<\/p>\n \/\/\u63a5\u6536\u4fe1\u606f<\/p>\n while(1)<\/p>\n {<\/p>\n char buf = {0};<\/p>\n<\/p>\n int ret = 0 ;<\/p>\n struct sockaddr_in client_addr = {0};<\/p>\n int len = sizeof(client_addr) ;<\/p>\n ret = recvfrom( fd , buf , sizeof(buf), 0 , <\/p>\n (struct sockaddr*)&client_addr ,<\/p>\n &len );<\/p>\n \/\/\u88ab\u4fe1\u53f7\u4e2d\u65ad\u5219\u91cd\u542f<\/p>\n if( (-1 == ret)&&(EINTR ==errno \u6881\u6089\u542f))<\/p>\n {<\/p>\n continue;<\/p>\n }<\/p>\n else if( -1 ==ret )<\/p>\n {<\/p>\n perror(\u201crecvfrom failed\u201d);<\/p>\n goto _out;<\/p>\n }<\/p>\n else if( ret >0 )<\/p>\n {<\/p>\n printf(\u201c%s\\n\u201d , buf );<\/p>\n }<\/p>\n usleep( 100*1000 );<\/p>\n }<\/p>\n _out:<\/p>\n if( fd >= 0)<\/p>\n {<\/p>\n close( fd );<\/p>\n }<\/p>\n return \u6a61\u59820;<\/p>\n }<\/p>\n \u628a\u865a\u62df\u673a\u7684\u7f51\u5361\u8bbe\u7f6e\u6210host only\u624d\u80fd\u5c06\u7ec4\u64ad\u5305\u653e\u884c\u3002<\/p>\n linux \u591a\u7f51\u5361\u7ec4\u64ad\u63a5\u6536\u7684\u4ecb\u7ecd\u5c31\u804a\u5230\u8fd9\u91cc\u5427\uff0c\u611f\u8c22\u4f60\u82b1\u65f6\u95f4\u9605\u8bfb\u672c\u7ad9\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8elinux \u591a\u7f51\u5361\u7ec4\u64ad\u63a5\u6536,Linux\u4e0b\u591a\u7f51\u5361\u5982\u4f55\u5b9e\u73b0\u7ec4\u64ad\u63a5\u6536\uff1f,linux \u600e\u6837\u52a0\u5165\u4e00\u4e2a\u591a\u64ad\u7ec4,linux\u4e0b\u5982\u4f55\u5f00\u542fmulticast\u7684\u4fe1\u606f\u522b\u5fd8\u4e86\u5728\u672c\u7ad9\u8fdb\u884c\u67e5\u627e\u5594\u3002<\/p>\n\n
linux \u600e\u6837\u52a0\u5165\u4e00\u4e2a\u591a\u64ad\u7ec4<\/h3>\n
linux\u4e0b\u5982\u4f55\u5f00\u542fmulticast<\/h3>\n