The branch main has been updated by glebius: URL: https://cgit.FreeBSD.org/src/commit/?id=be7bdb1cf0b0f665bcd57c03fde41bd6c01d8ead
commit be7bdb1cf0b0f665bcd57c03fde41bd6c01d8ead Author: Gleb Smirnoff <[email protected]> AuthorDate: 2025-10-15 18:54:57 +0000 Commit: Gleb Smirnoff <[email protected]> CommitDate: 2025-10-15 18:54:57 +0000 netinet: do route lookup when asked to join multicast group on ifindex 0 The code to do the route lookup was already there, but was used only for the legacy IP_ADD_MEMBERSHIP when called without index. Do same lookup for IP_ADD_MEMBERSHIP with index and what is more important for MCAST_JOIN_GROUP, if the supplied index is 0. This is a neat feature and Linux does that, so this should make a few applications easier portable to FreeBSD. Differential Revision: https://reviews.freebsd.org/D52918 --- sys/netinet/in_mcast.c | 113 ++++++++++++++-------------------- tests/sys/netinet/multicast-receive.c | 16 +++-- tests/sys/netinet/multicast.sh | 47 ++++++++++++++ 3 files changed, 104 insertions(+), 72 deletions(-) diff --git a/sys/netinet/in_mcast.c b/sys/netinet/in_mcast.c index f5b20c49ffd2..ba112afbf002 100644 --- a/sys/netinet/in_mcast.c +++ b/sys/netinet/in_mcast.c @@ -159,9 +159,6 @@ static struct ip_moptions * static int inp_get_source_filters(struct inpcb *, struct sockopt *); static int inp_join_group(struct inpcb *, struct sockopt *); static int inp_leave_group(struct inpcb *, struct sockopt *); -static struct ifnet * - inp_lookup_mcast_ifp(const struct inpcb *, - const struct sockaddr_in *, const struct in_addr); static int inp_block_unblock_source(struct inpcb *, struct sockopt *); static int inp_set_multicast_if(struct inpcb *, struct sockopt *); static int inp_set_source_filters(struct inpcb *, struct sockopt *); @@ -1832,69 +1829,55 @@ inp_getmoptions(struct inpcb *inp, struct sockopt *sopt) } /* - * Look up the ifnet to use for a multicast group membership, - * given the IPv4 address of an interface, and the IPv4 group address. - * - * This routine exists to support legacy multicast applications - * which do not understand that multicast memberships are scoped to - * specific physical links in the networking stack, or which need - * to join link-scope groups before IPv4 addresses are configured. - * - * Use this socket's current FIB number for any required FIB lookup. - * If ina is INADDR_ANY, look up the group address in the unicast FIB, - * and use its ifp; usually, this points to the default next-hop. - * - * If the FIB 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. - * - * Returns NULL if no ifp could be found, otherwise return referenced ifp. + * Look up the ifnet to join a multicast group membership via legacy + * IP_ADD_MEMBERSHIP or via more modern MCAST_JOIN_GROUP. * - * FUTURE: Implement IPv4 source-address selection. + * If the interface index was specified explicitly, just use it. If the + * address was specified (legacy), try to find matching interface. Else + * (index == 0 && no address) do a route lookup. If that fails for a modern + * MCAST_JOIN_GROUP return failure, for legacy IP_ADD_MEMBERSHIP find first + * multicast capable interface. */ static struct ifnet * -inp_lookup_mcast_ifp(const struct inpcb *inp, - const struct sockaddr_in *gsin, const struct in_addr ina) +inp_lookup_mcast_ifp(const struct inpcb *inp, const struct in_addr maddr, +const struct in_addr *ina, const u_int index) { struct ifnet *ifp; struct nhop_object *nh; NET_EPOCH_ASSERT(); - KASSERT(inp != NULL, ("%s: inp must not be NULL", __func__)); - KASSERT(gsin->sin_family == AF_INET, ("%s: not AF_INET", __func__)); - KASSERT(IN_MULTICAST(ntohl(gsin->sin_addr.s_addr)), - ("%s: not multicast", __func__)); - ifp = NULL; - if (!in_nullhost(ina)) { - INADDR_TO_IFP(ina, ifp); + if (index != 0) + return (ifnet_byindex_ref(index)); + + if (ina != NULL && !in_nullhost(*ina)) { + INADDR_TO_IFP(*ina, ifp); if (ifp != NULL) if_ref(ifp); - } else { - nh = fib4_lookup(inp->inp_inc.inc_fibnum, gsin->sin_addr, 0, NHR_NONE, 0); - if (nh != NULL) { - ifp = nh->nh_ifp; - if_ref(ifp); - } else { - struct in_ifaddr *ia; - struct ifnet *mifp; - - mifp = NULL; - CK_STAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) { - mifp = ia->ia_ifp; - if (!(mifp->if_flags & IFF_LOOPBACK) && - (mifp->if_flags & IFF_MULTICAST)) { - ifp = mifp; - if_ref(ifp); - break; - } + return (ifp); + } + + nh = fib4_lookup(inp->inp_inc.inc_fibnum, maddr, 0, NHR_NONE, 0); + if (nh != NULL) { + ifp = nh->nh_ifp; + if_ref(ifp); + return (ifp); + } + + if (ina != NULL) { + struct in_ifaddr *ia; + + CK_STAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) { + if (!(ia->ia_ifp->if_flags & IFF_LOOPBACK) && + (ia->ia_ifp->if_flags & IFF_MULTICAST)) { + ifp = ia->ia_ifp; + if_ref(ifp); + return (ifp); } } } - return (ifp); + return (NULL); } /* @@ -1926,13 +1909,13 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) switch (sopt->sopt_name) { case IP_ADD_MEMBERSHIP: { struct ip_mreqn mreqn; + bool mreq; - if (sopt->sopt_valsize == sizeof(struct ip_mreqn)) - error = sooptcopyin(sopt, &mreqn, - sizeof(struct ip_mreqn), sizeof(struct ip_mreqn)); - else - error = sooptcopyin(sopt, &mreqn, - sizeof(struct ip_mreq), sizeof(struct ip_mreq)); + mreq = (sopt->sopt_valsize != sizeof(struct ip_mreqn)); + + error = sooptcopyin(sopt, &mreqn, + mreq ? sizeof(struct ip_mreq) : sizeof(struct ip_mreqn), + mreq ? sizeof(struct ip_mreq) : sizeof(struct ip_mreqn)); if (error) return (error); @@ -1943,12 +1926,9 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) return (EINVAL); NET_EPOCH_ENTER(et); - if (sopt->sopt_valsize == sizeof(struct ip_mreqn) && - mreqn.imr_ifindex != 0) - ifp = ifnet_byindex_ref(mreqn.imr_ifindex); - else - ifp = inp_lookup_mcast_ifp(inp, &gsa->sin, - mreqn.imr_address); + ifp = inp_lookup_mcast_ifp(inp, mreqn.imr_multiaddr, + mreq ? &mreqn.imr_address : NULL, + mreq ? 0 : mreqn.imr_ifindex); NET_EPOCH_EXIT(et); break; } @@ -1971,8 +1951,8 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) ssa->sin.sin_addr = mreqs.imr_sourceaddr; NET_EPOCH_ENTER(et); - ifp = inp_lookup_mcast_ifp(inp, &gsa->sin, - mreqs.imr_interface); + ifp = inp_lookup_mcast_ifp(inp, mreqs.imr_multiaddr, + &mreqs.imr_interface, 0); NET_EPOCH_EXIT(et); CTR3(KTR_IGMPV3, "%s: imr_interface = 0x%08x, ifp = %p", __func__, ntohl(mreqs.imr_interface.s_addr), ifp); @@ -2013,7 +1993,8 @@ inp_join_group(struct inpcb *inp, struct sockopt *sopt) return (EINVAL); NET_EPOCH_ENTER(et); - ifp = ifnet_byindex_ref(gsr.gsr_interface); + ifp = inp_lookup_mcast_ifp(inp, gsa->sin.sin_addr, NULL, + gsr.gsr_interface); NET_EPOCH_EXIT(et); if (ifp == NULL) return (EADDRNOTAVAIL); diff --git a/tests/sys/netinet/multicast-receive.c b/tests/sys/netinet/multicast-receive.c index 81d0f10f5cfe..62fc68200dd6 100644 --- a/tests/sys/netinet/multicast-receive.c +++ b/tests/sys/netinet/multicast-receive.c @@ -36,6 +36,7 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <sysexits.h> #include <limits.h> #include <err.h> @@ -93,8 +94,9 @@ usage: .imr_multiaddr = maddr, .imr_interface = ifaddr, }; - assert(setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, - sizeof(mreq)) == 0); + if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, + sizeof(mreq)) != 0) + err(EX_OSERR, "setsockopt"); } else if (strcmp(argv[1], "ip_mreqn") == 0) { /* * ip_mreqn shall be used with index, but for testing @@ -105,8 +107,9 @@ usage: .imr_address = index ? (struct in_addr){ 0 } : ifaddr, .imr_ifindex = index ? ifindex : 0, }; - assert(setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreqn, - sizeof(mreqn)) == 0); + if (setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreqn, + sizeof(mreqn)) != 0) + err(EX_OSERR, "setsockopt"); } else if (strcmp(argv[1], "group_req") == 0) { if (!index) errx(1, "group_req expects index"); @@ -116,8 +119,9 @@ usage: gsa->sin_family = AF_INET; gsa->sin_len = sizeof(struct sockaddr_in); gsa->sin_addr = maddr; - assert(setsockopt(s, IPPROTO_IP, MCAST_JOIN_GROUP, &greq, - sizeof(greq)) == 0); + if (setsockopt(s, IPPROTO_IP, MCAST_JOIN_GROUP, &greq, + sizeof(greq)) != 0) + err(EX_OSERR, "setsockopt"); } else goto usage; diff --git a/tests/sys/netinet/multicast.sh b/tests/sys/netinet/multicast.sh index 273970d0f7ea..34094ff08705 100755 --- a/tests/sys/netinet/multicast.sh +++ b/tests/sys/netinet/multicast.sh @@ -79,6 +79,27 @@ IP_ADD_MEMBERSHIP_ip_mreq_body() 0.0.0.0 6676 233.252.0.1 6676 192.0.3.1 hello atf_check -s exit:0 sh -c "wait $pid; exit $?" atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out + + # join group on the first multicast capable interface (epair1a) + multicast_join ip_mreq 0.0.0.0 + atf_check -s exit:0 -o empty \ + jexec mjail1 $(atf_get_srcdir)/multicast-send \ + 0.0.0.0 6676 233.252.0.1 6676 192.0.2.1 hello + atf_check -s exit:0 sh -c "wait $pid; exit $?" + atf_check -s exit:0 -o inline:"192.0.2.1:6676 hello\n" cat out + + # Set up the receiving jail so that first multicast capable interface + # is epair1a and default route points into epair2a. This will allow us + # to exercise both branches of inp_lookup_mcast_ifp(). + jexec mjail2 route add default 192.0.3.254 + + # join group on the interface determined by the route lookup + multicast_join ip_mreq 0.0.0.0 + atf_check -s exit:0 -o empty \ + jexec mjail1 $(atf_get_srcdir)/multicast-send \ + 0.0.0.0 6676 233.252.0.1 6676 192.0.3.1 hello + atf_check -s exit:0 sh -c "wait $pid; exit $?" + atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out } IP_ADD_MEMBERSHIP_ip_mreq_cleanup() { @@ -111,6 +132,19 @@ IP_ADD_MEMBERSHIP_ip_mreqn_body() 0.0.0.0 6676 233.252.0.1 6676 ${epair2}a hello atf_check -s exit:0 sh -c "wait $pid; exit $?" atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out + + # try to join group on the interface determined by the route lookup + atf_check -s exit:71 -e inline:"multicast-receive: setsockopt: Can't assign requested address\n" \ + jexec mjail2 $(atf_get_srcdir)/multicast-receive \ + ip_mreqn 233.252.0.1 6676 0 + # add route and try again + jexec mjail2 route add default 192.0.3.254 + multicast_join ip_mreqn 0 + atf_check -s exit:0 -o empty \ + jexec mjail1 $(atf_get_srcdir)/multicast-send \ + 0.0.0.0 6676 233.252.0.1 6676 192.0.3.1 hello + atf_check -s exit:0 sh -c "wait $pid; exit $?" + atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out } IP_ADD_MEMBERSHIP_ip_mreqn_cleanup() { @@ -143,6 +177,19 @@ MCAST_JOIN_GROUP_body() 0.0.0.0 6676 233.252.0.1 6676 ${epair2}a hello atf_check -s exit:0 sh -c "wait $pid; exit $?" atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out + + # try to join group on the interface determined by the route lookup + atf_check -s exit:71 -e inline:"multicast-receive: setsockopt: Can't assign requested address\n" \ + jexec mjail2 $(atf_get_srcdir)/multicast-receive \ + group_req 233.252.0.1 6676 0 + # add route and try again + jexec mjail2 route add default 192.0.3.254 + multicast_join group_req 0 + atf_check -s exit:0 -o empty \ + jexec mjail1 $(atf_get_srcdir)/multicast-send \ + 0.0.0.0 6676 233.252.0.1 6676 192.0.3.1 hello + atf_check -s exit:0 sh -c "wait $pid; exit $?" + atf_check -s exit:0 -o inline:"192.0.3.1:6676 hello\n" cat out } MCAST_JOIN_GROUP_cleanup() {
