diff options
Diffstat (limited to 'set_mcast.c')
| -rw-r--r-- | set_mcast.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/set_mcast.c b/set_mcast.c new file mode 100644 index 0000000..aac3d36 --- /dev/null +++ b/set_mcast.c @@ -0,0 +1,160 @@ +/* + Copyright (C) 2006 Renaissance Technologies Corp. + main developer: HP Wei <hp@rentec.com> + + This file collects functions related to setting multicast + for multicaster. They are IPv4 and IPv6 ready. + By default, we use IPv4. + To use IPv6, we need to specify -DIPv6 in Makefile. + The functions in this file are collected from + Richard Stevens' Networking bible: Unix Network programming + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; see the file COPYING. + If not, write to the Free Software Foundation, + 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. +*/ + +#include "main.h" +#include <net/if.h> +#ifdef _SUN +#include <sys/sockio.h> /* define SIOCGIFADDR */ +#else +#include <linux/sockios.h> +#endif + +#define SA struct sockaddr +#define MAXSOCKADDR 128 /* max socket address structure size */ + +int sockfd_to_family(int sockfd) +{ + union { + struct sockaddr sa; + char data[MAXSOCKADDR]; + } un; + socklen_t len; + + len = MAXSOCKADDR; + if (getsockname(sockfd, (SA *) un.data, &len) < 0) + return(-1); + return(un.sa.sa_family); +} + +int mcast_set_if(int sockfd, const char *ifname, u_int ifindex) +{ + switch (sockfd_to_family(sockfd)) { + case AF_INET: { + struct in_addr inaddr; + struct ifreq ifreq; + + if (ifindex > 0) { + if (if_indextoname(ifindex, ifreq.ifr_name) == NULL) { + errno = ENXIO; /* i/f index not found */ + return(-1); + } + goto doioctl; + } else if (ifname != NULL) { + strncpy(ifreq.ifr_name, ifname, IFNAMSIZ); +doioctl: + if (ioctl(sockfd, SIOCGIFADDR, &ifreq) < 0) + return(-1); + memcpy(&inaddr, + &((struct sockaddr_in *) &ifreq.ifr_addr)->sin_addr, + sizeof(struct in_addr)); + } else + inaddr.s_addr = htonl(INADDR_ANY); /* remove prev. set default */ + + return(setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_IF, + &inaddr, sizeof(struct in_addr))); + } + +#ifdef IPV6 + case AF_INET6: { + u_int index; + + if ( (index = ifindex) == 0) { + if (ifname == NULL) { + errno = EINVAL; /* must supply either index or name */ + return(-1); + } + if ( (index = if_nametoindex(ifname)) == 0) { + errno = ENXIO; /* i/f name not found */ + return(-1); + } + } + return(setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_IF, + &index, sizeof(index))); + } +#endif + + default: + errno = EPROTONOSUPPORT; + return(-1); + } +} + +int mcast_set_loop(int sockfd, int onoff) +{ + switch (sockfd_to_family(sockfd)) { + case AF_INET: { + u_char flag; + + flag = onoff; + return(setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_LOOP, + &flag, sizeof(flag))); + } + +#ifdef IPV6 + case AF_INET6: { + u_int flag; + + flag = onoff; + return(setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, + &flag, sizeof(flag))); + } +#endif + + default: + errno = EPROTONOSUPPORT; + return(-1); + } +} +/* end mcast_set_loop */ + +int mcast_set_ttl(int sockfd, int val) +{ + switch (sockfd_to_family(sockfd)) { + case AF_INET: { + u_char ttl; + + ttl = val; + return(setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, + &ttl, sizeof(ttl))); + } + +#ifdef IPV6 + case AF_INET6: { + int hop; + + hop = val; + return(setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, + &hop, sizeof(hop))); + } +#endif + + default: + errno = EPROTONOSUPPORT; + return(-1); + } +} + |