From c9e3e8b6958e02230079e6817862ea2968509866 Mon Sep 17 00:00:00 2001 From: David L Stevens Date: Tue, 21 Jun 2005 13:58:25 -0700 Subject: [PATCH] [IPV6]: multicast join and misc Here is a simplified version of the patch to fix a bug in IPv6 multicasting. It: 1) adds existence check & EADDRINUSE error for regular joins 2) adds an exception for EADDRINUSE in the source-specific multicast join (where a prior join is ok) 3) adds a missing/needed read_lock on sock_mc_list; would've raced with destroying the socket on interface down without 4) adds a "leave group" in the (INCLUDE, empty) source filter case. This frees unneeded socket buffer memory, but also prevents an inappropriate interaction among the 8 socket options that mess with this. Some would fail as if in the group when you aren't really. Item #4 had a locking bug in the last version of this patch; rather than removing the idev->lock read lock only, I've simplified it to remove all lock state in the path and treat it as a direct "leave group" call for the (INCLUDE,empty) case it covers. Tested on an MP machine. :-) Much thanks to HoerdtMickael who reported the original bug. Signed-off-by: David L Stevens Signed-off-by: David S. Miller --- net/ipv6/ipv6_sockglue.c | 5 +++-- net/ipv6/mcast.c | 21 +++++++++++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 279ab86be66..f3ef4c38d31 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -423,11 +423,12 @@ done: psin6 = (struct sockaddr_in6 *)&greqs.gsr_group; retv = ipv6_sock_mc_join(sk, greqs.gsr_interface, &psin6->sin6_addr); - if (retv) + /* prior join w/ different source is ok */ + if (retv && retv != -EADDRINUSE) break; omode = MCAST_INCLUDE; add = 1; - } else /*IP_DROP_SOURCE_MEMBERSHIP */ { + } else /* MCAST_LEAVE_SOURCE_GROUP */ { omode = MCAST_INCLUDE; add = 0; } diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 393b6e6f50a..c0ca92e8230 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -188,6 +188,16 @@ int ipv6_sock_mc_join(struct sock *sk, int ifindex, struct in6_addr *addr) if (!ipv6_addr_is_multicast(addr)) return -EINVAL; + read_lock_bh(&ipv6_sk_mc_lock); + for (mc_lst=np->ipv6_mc_list; mc_lst; mc_lst=mc_lst->next) { + if ((ifindex == 0 || mc_lst->ifindex == ifindex) && + ipv6_addr_equal(&mc_lst->addr, addr)) { + read_unlock_bh(&ipv6_sk_mc_lock); + return -EADDRINUSE; + } + } + read_unlock_bh(&ipv6_sk_mc_lock); + mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL); if (mc_lst == NULL) @@ -349,6 +359,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk, struct ipv6_pinfo *inet6 = inet6_sk(sk); struct ip6_sf_socklist *psl; int i, j, rv; + int leavegroup = 0; int err; if (pgsr->gsr_group.ss_family != AF_INET6 || @@ -368,6 +379,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk, err = -EADDRNOTAVAIL; + read_lock_bh(&ipv6_sk_mc_lock); for (pmc=inet6->ipv6_mc_list; pmc; pmc=pmc->next) { if (pgsr->gsr_interface && pmc->ifindex != pgsr->gsr_interface) continue; @@ -401,6 +413,12 @@ int ip6_mc_source(int add, int omode, struct sock *sk, if (rv) /* source not found */ goto done; + /* special case - (INCLUDE, empty) == LEAVE_GROUP */ + if (psl->sl_count == 1 && omode == MCAST_INCLUDE) { + leavegroup = 1; + goto done; + } + /* update the interface filter */ ip6_mc_del_src(idev, group, omode, 1, source, 1); @@ -453,9 +471,12 @@ int ip6_mc_source(int add, int omode, struct sock *sk, /* update the interface list */ ip6_mc_add_src(idev, group, omode, 1, source, 1); done: + read_unlock_bh(&ipv6_sk_mc_lock); read_unlock_bh(&idev->lock); in6_dev_put(idev); dev_put(dev); + if (leavegroup) + return ipv6_sock_mc_drop(sk, pgsr->gsr_interface, group); return err; } -- 2.20.1