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134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/*
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* BIRD Internet Routing Daemon -- Linux Multicasting and Network Includes
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*
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* (c) 1998--1999 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifdef IPV6
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#include <linux/in6.h> /* FIXMEv6: glibc variant? */
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static inline void
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set_inaddr(struct in6_addr *ia, ip_addr a)
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{
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ipa_hton(a);
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memcpy(ia, &a, sizeof(a));
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}
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#else
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static inline void
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set_inaddr(struct in_addr *ia, ip_addr a)
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{
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ipa_hton(a);
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memcpy(&ia->s_addr, &a, sizeof(a));
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}
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/*
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* Multicasting in Linux systems is a real mess. Not only different kernels
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* have different interfaces, but also different libc's export it in different
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* ways. Horrible.
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*/
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static inline char *sysio_mcast_setup(sock *s)
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{
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int zero = 0;
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if (ipa_nonzero(s->daddr))
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{
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if (
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#ifdef IP_DEFAULT_MULTICAST_TTL
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s->ttl != IP_DEFAULT_MULTICAST_TTL &&
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#endif
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setsockopt(s->fd, SOL_IP, IP_MULTICAST_TTL, &s->ttl, sizeof(s->ttl)) < 0)
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return "IP_MULTICAST_TTL";
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if (
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#ifdef IP_DEFAULT_MULTICAST_LOOP
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IP_DEFAULT_MULTICAST_LOOP &&
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#endif
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setsockopt(s->fd, SOL_IP, IP_MULTICAST_LOOP, &zero, sizeof(zero)) < 0)
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return "IP_MULTICAST_LOOP";
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}
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return NULL;
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}
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#ifdef CONFIG_LINUX_MC_MREQN
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/*
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* 2.1 and newer kernels use struct mreqn which passes ifindex, so no
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* problems with unnumbered devices.
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*/
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#ifndef HAVE_STRUCT_IP_MREQN
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/* Several versions of glibc don't define this structure, so we have to do it ourselves */
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struct ip_mreqn
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{
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struct in_addr imr_multiaddr; /* IP multicast address of group */
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struct in_addr imr_address; /* local IP address of interface */
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int imr_ifindex; /* Interface index */
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};
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#endif
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static inline char *sysio_mcast_join(sock *s)
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{
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struct ip_mreqn mreq;
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char *err;
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if (err = sysio_mcast_setup(s))
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return err;
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mreq.imr_ifindex = s->iface->index;
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set_inaddr(&mreq.imr_address, s->iface->addr->ip);
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set_inaddr(&mreq.imr_multiaddr, s->daddr);
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/* This defines where should we send _outgoing_ multicasts */
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if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) < 0)
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return "IP_MULTICAST_IF";
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/* And this one sets interface for _receiving_ multicasts from */
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if (ipa_nonzero(s->saddr) && setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
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return "IP_ADD_MEMBERSHIP";
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return NULL;
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}
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#endif
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#if defined(CONFIG_LINUX_MC_MREQ) || defined(CONFIG_LINUX_MC_MREQ_BIND)
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/*
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* Older kernels support only struct mreq which matches interfaces by their
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* addresses and thus fails on unnumbered devices. On newer 2.0 kernels
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* we can use SO_BINDTODEVICE to circumvent this problem.
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*/
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#include <net/if.h>
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static inline char *sysio_mcast_join(sock *s)
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{
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struct in_addr mreq;
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struct ip_mreq mreq_add;
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char *err;
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if (err = sysio_mcast_setup(s))
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return err;
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set_inaddr(&mreq, s->iface->addr->ip);
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#ifdef CONFIG_LINUX_MC_MREQ_BIND
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{
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struct ifreq ifr;
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strcpy(ifr.ifr_name, s->iface->name);
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if (setsockopt(s->fd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr)) < 0)
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return "SO_BINDTODEVICE";
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mreq_add.imr_interface.s_addr = INADDR_ANY;
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}
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#else
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mreq_add.imr_interface = mreq;
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#endif
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set_inaddr(&mreq_add.imr_multiaddr, s->daddr);
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/* This defines where should we send _outgoing_ multicasts */
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if (setsockopt(s->fd, SOL_IP, IP_MULTICAST_IF, &mreq, sizeof(mreq)) < 0)
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return "IP_MULTICAST_IF";
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/* And this one sets interface for _receiving_ multicasts from */
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if (ipa_nonzero(s->saddr) && setsockopt(s->fd, SOL_IP, IP_ADD_MEMBERSHIP, &mreq_add, sizeof(mreq_add)) < 0)
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return "IP_ADD_MEMBERSHIP";
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return NULL;
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}
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#endif
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#endif
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