Strange thing on IPv6 multicast program on Windows
- by zhanglistar
I have written an ipv6 multicast program on windows xp sp3.
But a problem bothers me a lot. The sendto function implies no error, but
I can't capture the packet using wireshark. I am sure the filter is right.
Thanks in advance.
And the code is as follows:
#include "stdafx.h"
#include <stdio.h> /* for printf() and fprintf() */
#include <winsock2.h> /* for socket(), connect(), sendto(), and recvfrom() */
#include <ws2tcpip.h> /* for ip_mreq */
#include <stdlib.h> /* for atoi() and exit() */
#include <string.h> /* for memset() */
#include <time.h> /* for timestamps */
#include <pcap.h>
#include <Iphlpapi.h>
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "wpcap.lib")
#pragma comment(lib, "Iphlpapi.lib")
int _tmain(int argc, _TCHAR* argv[])
{
int sfd;
int on, length, iResult;
WSADATA wsaData;
struct addrinfo Hints;
struct addrinfo *multicastAddr, *localAddr;
char buf[46];
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed: %d\n", iResult);
return 1;
}
/* Resolve destination address for multicast datagrams */
memset(&Hints, 0, sizeof (Hints));
Hints.ai_family = AF_INET6;
Hints.ai_socktype = SOCK_DGRAM;
Hints.ai_protocol = IPPROTO_UDP;
Hints.ai_flags = AI_NUMERICHOST;
iResult = getaddrinfo("FF02::1:2", "547", &Hints, &multicastAddr);
if (iResult != 0) {
/* error handling */
printf("socket error: %d\n", WSAGetLastError());
return -1;
}
/* Get a local address with the same family (IPv4 or IPv6) as our multicast group */
Hints.ai_family = multicastAddr->ai_family;
Hints.ai_socktype = SOCK_DGRAM;
Hints.ai_flags = AI_PASSIVE; /* Return an address we can bind to */
if ( getaddrinfo(NULL, "546", &Hints, &localAddr) != 0 )
{
printf("getaddrinfo() failed: %d\n", WSAGetLastError());
exit(-1);
}
// Create sending socket
//sfd = socket (multicastAddr->ai_family, multicastAddr->ai_socktype, multicastAddr->ai_protocol);
sfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);
if (sfd == -1)
{
printf("socket error: %d\n", WSAGetLastError());
return 0;
}
/* Bind to the multicast port */
if ( bind(sfd, localAddr->ai_addr, localAddr->ai_addrlen) != 0 )
{
printf("bind() failed: %d\n", WSAGetLastError());
exit(-1);
}
if (multicastAddr->ai_family == AF_INET6 &&
multicastAddr->ai_addrlen == sizeof(struct sockaddr_in6)) /* IPv6 */
{
on = 1;
if (setsockopt (sfd, IPPROTO_IPV6, IPV6_MULTICAST_IF, (char *)&on, sizeof (on) /*(char *)&interface_addr,
sizeof(interface_addr)*/) == -1)
{
printf("setsockopt error:%d\n", WSAGetLastError());
return -1;
}
if (setsockopt (sfd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, (char *)&on, sizeof (on) /*(char *)&interface_addr,
sizeof(interface_addr)*/) == -1)
{
printf("setsockopt error:%d\n", WSAGetLastError());
return -1;
}
struct ipv6_mreq multicastRequest; /* Multicast address join structure */
/* Specify the multicast group */
memcpy(&multicastRequest.ipv6mr_multiaddr,
&((struct sockaddr_in6*)(multicastAddr->ai_addr))->sin6_addr,
sizeof(struct in6_addr));
/* Accept multicast from any interface */
multicastRequest.ipv6mr_interface = 0;
/* Join the multicast address */
if ( setsockopt(sfd, IPPROTO_IPV6, IPV6_JOIN_GROUP, (char*) &multicastRequest, sizeof(multicastRequest)) != 0 )
{
printf("setsockopt() failed: %d\n", WSAGetLastError());
return -1;
}
on = 1;
if (setsockopt (sfd, IPPROTO_IPV6, IPV6_MULTICAST_IF, (char *)&on, sizeof (on)) == -1)
{
printf("setsockopt error:%d\n", WSAGetLastError());
return 0;
}
}
memset(buf, 0, sizeof(buf));
strcpy(buf, "hello world");
iResult = sendto(sfd, buf, strlen(buf), 0,
(LPSOCKADDR) multicastAddr->ai_addr, multicastAddr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
printf("setsockopt error:%d\n", WSAGetLastError());
return -1;
/* Error handling */
}
return 0;
}
