Messages in this thread | | | Subject | Re: Usage of SIOCADDMULTI ? | From | Terje Eggestad <> | Date | 29 Aug 2001 10:18:18 +0200 |
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According to ip(7) you should use setsockopt, the following works for me (PS: I'm running 2.4.3 and I get EPERM as non root and EINVAL as root when running your code.)
#include <net/if.h> #include <netinet/in.h> #include <stdio.h> #include <errno.h> #include <sys/types.h> #include <sys/socket.h> #include <sys/ioctl.h> #include <netdb.h>
#define ASSERT(a, op, b, m...) do { if ( a op b) { \ fprintf(stderr, "ASSERT (" #a " " #op " " #b ") at %s line %d:", __FILE__, __LINE__); \ fprintf(stderr, m);\ fprintf(stderr, "\n"); \ fflush(stderr); exit(-1); }} while(0)
struct ifreq ir; struct ip_mreq mr;
int createmcast() { int s, rc; struct hostent * he; struct sockaddr_in to;
s = socket(AF_INET, SOCK_DGRAM, 0);
ASSERT (s, == , -1, "socket failed errno=%d", errno); mr.imr_interface.s_addr = (in_addr_t) htonl(INADDR_ANY);
to.sin_family = AF_INET; to.sin_port = 0; to.sin_addr.s_addr = htonl(INADDR_ANY); // bind(s, &to, sizeof(struct sockaddr_in));
he = gethostbyname("172.16.0.116"); ASSERT (he, ==, NULL, "gethostbyname if failed %d", h_errno); // memcpy (&mr.imr_interface, &he->h_addr_list[0], sizeof (struct sockaddr_in));
he = gethostbyname("225.0.0.100"); ASSERT (he, ==, NULL, "gethostbyname mc failed %d", h_errno); memcpy (&mr.imr_multiaddr, he->h_addr_list[0], sizeof (struct sockaddr_in)); errno = 0; printf ("%#x %#x\n", mr.imr_multiaddr.s_addr, mr.imr_interface.s_addr); rc = setsockopt (s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mr, sizeof(struct ip_mreq));
ASSERT (rc, <, 0, "setsockopt (.., IPPROTO_IP, IP_ADD_MEMBERSHIP, ..) failed errno=%d", errno); rc = setsockopt (s, IPPROTO_IP, IP_MULTICAST_IF, &mr.imr_interface, sizeof(struct in_addr));
ASSERT (rc, <, 0, "setsockopt (.., IPPROTO_IP, IP_MULTICAST_IF, ..) failed errno=%d", errno);
return s; };
int createudp() { int s, rc; struct sockaddr_in to; s = socket(AF_INET, SOCK_DGRAM, 0);
to.sin_family = AF_INET; to.sin_port = htons(12345); to.sin_addr.s_addr = htonl(INADDR_ANY); rc = bind(s, &to, sizeof(struct sockaddr_in)); ASSERT (rc, ==, -1, "bind failed %d", errno); return s; };
int sendmcast (int s, char * payload, int plen) { int rc; struct sockaddr_in to;
to.sin_family = AF_INET; to.sin_port = htons(12345); memcpy(&to.sin_addr, &mr.imr_multiaddr.s_addr, sizeof(struct in_addr));
if (plen == 0) plen = strlen(payload);
rc = sendto (s, payload, plen , 0, &to, sizeof(struct sockaddr_in));
printf ("sendto returned %d\n", rc); ASSERT (rc, <, 0, "snndto () failed errno=%d", errno);
};
char * getdgram(int s) { struct sockaddr_in from; int rc; static char buffer[1024]; static char addrbuf[100]; socklen_t fromlen;
fromlen = sizeof(struct sockaddr_in); rc = recvfrom(s, buffer, 1024, 0, &from, &fromlen); inet_ntop(AF_INET, &from.sin_addr, addrbuf, 100); printf ("from socket %d, we got a message %s sender %s:%d (%d)\n", s, buffer, addrbuf , ntohs(from.sin_port), fromlen); return buffer; }; main() { int ms, us; int rc;
ms = createmcast(); us = createudp();
sendmcast(us, "heihei", 0);
sleep(3); getdgram(us);
exit(0);
// rc = ioctl (s, SIOCGIFADDR, &ir);
//ASSERT (rc, <, 0, "ioctl failed errno=%d", errno); };
Den 28 Aug 2001 22:56:10 +0200, skrev Peter Enderborg: > Im trying to grab some ethernet multicasts. And the ioctl that should do > that is SIOCADDMULTI. > But I can't get it to work. And I have not found any who use that from > userlevel so > this is my guess who to do it. (I don't work but dont gives any error > message) > > > #include <stdio.h> > #include <sys/ioctl.h> > #include <net/if.h> > #include <arpa/inet.h> > #include <errno.h> > #include <sys/un.h> > > int main() > { > int i,res,sock,from_len; > struct sockaddr_in eb_addr,from_addr; > char databuf[1500]; > struct ifreq req; > > > if((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) > { > printf("%s",strerror(errno)); > exit(1); > } > > eb_addr.sin_family = AF_INET; > /* eb_addr.sin_family = AF_UNSPEC; */ > eb_addr.sin_addr.s_addr = inet_addr("0.0.0.0"); > eb_addr.sin_port = htons(4711); > > for (i = 0; i < 8; ++i) > eb_addr.sin_zero[i] = 0; > if(bind(sock,(struct sockaddr*) &eb_addr, sizeof(struct sockaddr_in)) > == -1) > { > printf("Unable to bind the socket\n"); > exit(1); > } > strcpy(req.ifr_name,"eth0"); > req.ifr_ifru.ifru_addr.sa_data[0] = 0x01; > req.ifr_ifru.ifru_addr.sa_data[1] = 0x80; > req.ifr_ifru.ifru_addr.sa_data[2] = 0xc2; > req.ifr_ifru.ifru_addr.sa_data[3] = 0x00; > req.ifr_ifru.ifru_addr.sa_data[4] = 0x00; > req.ifr_ifru.ifru_addr.sa_data[5] = 0x00; > /* req.ifr_flags = IFF_ALLMULTI; | IFF_PROMISC; */ > res = ioctl(sock,SIOCADDMULTI,&req); > if(res == -1) > { > printf("%s",strerror(errno)); > exit(1); > } > > while (1) > { > printf("enter recvfrom\n"); > res = recvfrom(sock, databuf, sizeof(databuf), 0,(struct > sockaddr*) &from_addr, &from_len); > printf("Received %d bytes\n", res ); > } > return 0; > } > > This on a 2.4.9 kernel on SMP P2. Im trying to grab some 802 bridge > packets and I see them > with tcpdump but that is using a other interface. (BPF or what ever) Any > ideas whats wrong ? > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- _________________________________________________________________________
Terje Eggestad terje.eggestad@scali.no Scali Scalable Linux Systems http://www.scali.com
Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE) P.O.Box 70 Bogerud +47 975 31 574 (MOBILE) N-0621 Oslo fax: +47 22 62 89 51 NORWAY _________________________________________________________________________
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