diff options
Diffstat (limited to 'sys/netinet/in_mcast.c')
| -rw-r--r-- | sys/netinet/in_mcast.c | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/sys/netinet/in_mcast.c b/sys/netinet/in_mcast.c index 0f0dc2d..4995800 100644 --- a/sys/netinet/in_mcast.c +++ b/sys/netinet/in_mcast.c @@ -996,8 +996,16 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) /* * Obtain ifp. If no interface address was provided, - * use the interface of the route to the given multicast - * address (usually this is the default route). + * use the interface of the route in the unicast FIB for + * the given multicast destination; usually, this is the + * default route. + * If this lookup fails, attempt to use the first non-loopback + * interface with multicast capability in the system as a + * last resort. The legacy IPv4 ASM API requires that we do + * this in order to allow groups to be joined when the routing + * table has not yet been populated during boot. + * If all of these conditions fail, return EADDRNOTAVAIL, and + * reject the IPv4 multicast join. */ if (mreqs.imr_interface.s_addr != INADDR_ANY) { INADDR_TO_IFP(mreqs.imr_interface, ifp); @@ -1007,16 +1015,23 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) ro.ro_rt = NULL; *(struct sockaddr_in *)&ro.ro_dst = gsa->sin; rtalloc_ign(&ro, RTF_CLONING); - if (ro.ro_rt == NULL) { -#ifdef DIAGNOSTIC - printf("%s: no route to %s\n", __func__, - inet_ntoa(gsa->sin.sin_addr)); -#endif - return (EADDRNOTAVAIL); + if (ro.ro_rt != NULL) { + ifp = ro.ro_rt->rt_ifp; + KASSERT(ifp != NULL, ("%s: null ifp", + __func__)); + RTFREE(ro.ro_rt); + } else { + struct in_ifaddr *ia; + struct ifnet *mfp = NULL; + TAILQ_FOREACH(ia, &in_ifaddrhead, ia_link) { + mfp = ia->ia_ifp; + if (!(mfp->if_flags & IFF_LOOPBACK) && + (mfp->if_flags & IFF_MULTICAST)) { + ifp = mfp; + break; + } + } } - ifp = ro.ro_rt->rt_ifp; - KASSERT(ifp != NULL, ("%s: null ifp", __func__)); - RTFREE(ro.ro_rt); } #ifdef DIAGNOSTIC if (bootverbose) { |
