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/*
* BIRD Internet Routing Daemon -- Linux Multicasting and Network Includes
*
* (c) 1998--1999 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifdef IPV6
#include <linux/in6.h> /* FIXMEv6: glibc variant? */
#else
/*
* Multicasting in Linux systems is a real mess. Not only different kernels
* have different interfaces, but also different libc's export it in different
* ways. Horrible.
*/
static inline char *sysio_mcast_setup(sock *s)
{
int zero = 0;
if (ipa_nonzero(s->daddr))
{
if (
#ifdef IP_DEFAULT_MULTICAST_TTL
s->ttl != IP_DEFAULT_MULTICAST_TTL &&
#endif
setsockopt(s->fd, SOL_IP, IP_MULTICAST_TTL, &s->ttl, sizeof(s->ttl)) < 0)
return "IP_MULTICAST_TTL";
if (
#ifdef IP_DEFAULT_MULTICAST_LOOP
IP_DEFAULT_MULTICAST_LOOP &&
#endif
setsockopt(s->fd, SOL_IP, IP_MULTICAST_LOOP, &zero, sizeof(zero)) < 0)
return "IP_MULTICAST_LOOP";
}
return NULL;
}
#ifdef CONFIG_LINUX_MC_MREQN
/*
* 2.1 and newer kernels use struct mreqn which passes ifindex, so no
* problems with unnumbered devices.
*/
#ifndef HAVE_STRUCT_IP_MREQN
/* Several versions of glibc don't define this structure, so we have to do it ourselves */
struct ip_mreqn
{
struct in_addr imr_multiaddr; /* IP multicast address of group */
struct in_addr imr_address; /* local IP address of interface */
int imr_ifindex; /* Interface index */
};
#endif
static inline char *sysio_mcast_join(sock *s)
{
struct ip_mreqn mreq;
char *err;
if (err = sysio_mcast_setup(s))
return err;
mreq.imr_ifindex = s->iface->index;
set_inaddr(&mreq.imr_address, s->iface->addr->ip);
set_inaddr(&mreq.imr_multiaddr, s->daddr);
/* This defines where should we send _outgoing_ multicasts */
if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) < 0)
return "IP_MULTICAST_IF";
/* And this one sets interface for _receiving_ multicasts from */
if (ipa_nonzero(s->saddr) && setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
return "IP_ADD_MEMBERSHIP";
return NULL;
}
#endif
#if defined(CONFIG_LINUX_MC_MREQ) || defined(CONFIG_LINUX_MC_MREQ_BIND)
/*
* Older kernels support only struct mreq which matches interfaces by their
* addresses and thus fails on unnumbered devices. On newer 2.0 kernels
* we can use SO_BINDTODEVICE to circumvent this problem.
*/
#include <net/if.h>
static inline char *sysio_mcast_join(sock *s)
{
struct in_addr mreq;
struct ip_mreq mreq_add;
char *err;
if (err = sysio_mcast_setup(s))
return err;
set_inaddr(&mreq, s->iface->addr->ip);
#ifdef CONFIG_LINUX_MC_MREQ_BIND
{
struct ifreq ifr;
strcpy(ifr.ifr_name, s->iface->name);
if (setsockopt(s->fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
return "SO_BINDTODEVICE";
mreq_add.imr_interface.s_addr = INADDR_ANY;
}
#else
mreq_add.imr_interface = mreq;
#endif
set_inaddr(&mreq_add.imr_multiaddr, s->daddr);
/* This defines where should we send _outgoing_ multicasts */
if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) < 0)
return "IP_MULTICAST_IF";
/* And this one sets interface for _receiving_ multicasts from */
if (ipa_nonzero(s->saddr) && setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq_add, sizeof(mreq_add)) < 0)
return "IP_ADD_MEMBERSHIP";
return NULL;
}
#endif
#endif
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