mirror of
https://github.com/riba2534/TCP-IP-NetworkNote.git
synced 2026-02-02 17:48:55 +08:00
55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <arpa/inet.h>
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#include <sys/socket.h>
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#define BUF_SIZE 30
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void error_handling(char *message);
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int main(int argc, char *argv[])
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{
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int recv_sock;
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int str_len;
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char buf[BUF_SIZE];
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struct sockaddr_in adr;
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struct ip_mreq join_adr;
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if (argc != 3)
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{
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printf("Usage : %s <GroupIP> <PORT>\n", argv[0]);
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exit(1);
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}
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recv_sock = socket(PF_INET, SOCK_DGRAM, 0);
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memset(&adr, 0, sizeof(adr));
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adr.sin_family = AF_INET;
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adr.sin_addr.s_addr = htonl(INADDR_ANY);
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adr.sin_port = htons(atoi(argv[2]));
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if (bind(recv_sock, (struct sockaddr *)&adr, sizeof(adr)) == -1)
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error_handling("bind() error");
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//初始化结构体
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join_adr.imr_multiaddr.s_addr = inet_addr(argv[1]); //多播组地址
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join_adr.imr_interface.s_addr = htonl(INADDR_ANY); //待加入的IP地址
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//利用套接字选项 IP_ADD_MEMBERSHIP 加入多播组，完成了接受指定的多播组数据的所有准备
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setsockopt(recv_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *)&join_adr, sizeof(join_adr));
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while (1)
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{
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//通过 recvfrom 函数接受多播数据。如果不需要知道传输数据的主机地址信息，可以向recvfrom函数的第5 6参数分贝传入 NULL 0
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str_len = recvfrom(recv_sock, buf, BUF_SIZE - 1, 0, NULL, 0);
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if (str_len < 0)
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break;
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buf[str_len] = 0;
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fputs(buf, stdout);
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}
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close(recv_sock);
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return 0;
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}
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void error_handling(char *message)
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{
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fputs(message, stderr);
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fputc('\n', stderr);
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exit(1);
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} |