Socket多播收包的问题

redice

这样一段多播发送接收的代码，看起来没有问题，发送方的包可以抓到，但是接收方没有任何反应，请教一下高人问题出在哪里，gcc版本4.4.0, Fedora 11

Server启动以后用netstat没看到port 12345

Listener:

1. Listener Program
   
2. 
   
3. /*
   
4. * listener.c -- joins a multicast group and echoes all data it receives from
   
5. *                the group to its stdout...
   
6. *
   
7. * Antony Courtney,        25/11/94
   
8. * Modified by: Frédéric Bastien (25/03/04)
   
9. * to compile without warning and work correctly
   
10. */
    
11. 
    
12. #include <sys/types.h>
    
13. #include <sys/socket.h>
    
14. #include <netinet/in.h>
    
15. #include <arpa/inet.h>
    
16. #include <time.h>
    
17. #include <string.h>
    
18. #include <stdio.h>
    
19. 
    
20. 
    
21. #define HELLO_PORT 12345
    
22. #define HELLO_GROUP "225.0.0.37"
    
23. #define MSGBUFSIZE 256
    
24. 
    
25. main(int argc, char *argv[])
    
26. {
    
27.      struct sockaddr_in addr;
    
28.      int fd, nbytes,addrlen;
    
29.      struct ip_mreq mreq;
    
30.      char msgbuf[MSGBUFSIZE];
    
31. 
    
32.      u_int yes=1;            /*** MODIFICATION TO ORIGINAL */
    
33. 
    
34.      /* create what looks like an ordinary UDP socket */
    
35.      if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
    
36.           perror("socket");
    
37.           exit(1);
    
38.      }
    
39. 
    
40. 
    
41. /**** MODIFICATION TO ORIGINAL */
    
42.     /* allow multiple sockets to use the same PORT number */
    
43.     if (setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(yes)) < 0) {
    
44.        perror("Reusing ADDR failed");
    
45.        exit(1);
    
46.        }
    
47. /*** END OF MODIFICATION TO ORIGINAL */
    
48. 
    
49.      /* set up destination address */
    
50.      memset(&addr,0,sizeof(addr));
    
51.      addr.sin_family=AF_INET;
    
52.      addr.sin_addr.s_addr=htonl(INADDR_ANY); /* N.B.: differs from sender */
    
53.      addr.sin_port=htons(HELLO_PORT);
    
54.      
    
55.      /* bind to receive address */
    
56.      if (bind(fd,(struct sockaddr *) &addr,sizeof(addr)) < 0) {
    
57.           perror("bind");
    
58.           exit(1);
    
59.      }
    
60.      
    
61.      /* use setsockopt() to request that the kernel join a multicast group */
    
62.      mreq.imr_multiaddr.s_addr=inet_addr(HELLO_GROUP);
    
63.      mreq.imr_interface.s_addr=htonl(INADDR_ANY);
    
64.      if (setsockopt(fd,IPPROTO_IP,IP_ADD_MEMBERSHIP,&mreq,sizeof(mreq)) < 0) {
    
65.           perror("setsockopt");
    
66.           exit(1);
    
67.      }
    
68. 
    
69.      /* now just enter a read-print loop */
    
70.      while (1) {
    
71.           addrlen=sizeof(addr);
    
72.           if ((nbytes=recvfrom(fd,msgbuf,MSGBUFSIZE,0,
    
73.                                (struct sockaddr *) &addr,&addrlen)) < 0) {
    
74.                perror("recvfrom");
    
75.                exit(1);
    
76.           }
    
77.           puts(msgbuf);
    
78.      }
    
79. }
    

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Sender:

1. Sender Program
   
2. 
   
3. /*
   
4. * sender.c -- multicasts "hello, world!" to a multicast group once a second
   
5. *
   
6. * Antony Courtney,        25/11/94
   
7. */
   
8. 
   
9. #include <sys/types.h>
   
10. #include <sys/socket.h>
    
11. #include <netinet/in.h>
    
12. #include <arpa/inet.h>
    
13. #include <time.h>
    
14. #include <string.h>
    
15. #include <stdio.h>
    
16. 
    
17. 
    
18. #define HELLO_PORT 12345
    
19. #define HELLO_GROUP "225.0.0.37"
    
20. 
    
21. main(int argc, char *argv[])
    
22. {
    
23.      struct sockaddr_in addr;
    
24.      int fd, cnt;
    
25.      struct ip_mreq mreq;
    
26.      char *message="Hello, World!";
    
27. 
    
28.      /* create what looks like an ordinary UDP socket */
    
29.      if ((fd=socket(AF_INET,SOCK_DGRAM,0)) < 0) {
    
30.           perror("socket");
    
31.           exit(1);
    
32.      }
    
33. 
    
34.      /* set up destination address */
    
35.      memset(&addr,0,sizeof(addr));
    
36.      addr.sin_family=AF_INET;
    
37.      addr.sin_addr.s_addr=inet_addr(HELLO_GROUP);
    
38.      addr.sin_port=htons(HELLO_PORT);
    
39.      
    
40.      /* now just sendto() our destination! */
    
41.      while (1) {
    
42.           if (sendto(fd,message,sizeof(message),0,(struct sockaddr *) &addr,
    
43.                      sizeof(addr)) < 0) {
    
44.                perror("sendto");
    
45.                exit(1);
    
46.           }
    
47.           sleep(1);
    
48.      }
    
49. }
    

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谢谢了先

redice

问题解决了，fedora11主机iptables的问题，刷掉filter规则就可以了，暂时结贴，谢谢