[IPV4]: multicast API "join" issues

1) Changes IP_ADD_SOURCE_MEMBERSHIP and MCAST_JOIN_SOURCE_GROUP to ignore
   EADDRINUSE errors on a "courtesy join" -- prior membership or not
   is ok for these.

2) Adds "leave group" equivalence of (INCLUDE, empty) filters in the 
   delta-based API. Without this, mixing delta-based API calls that
   end in an (INCLUDE, empty) filter would not allow a subsequent
   regular IP_ADD_MEMBERSHIP. It also frees socket buffer memory that
   isn't needed for both the multicast group record and source filter.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index f8b172f89811..fc7c481d0d79 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -677,11 +677,11 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
                                 mreq.imr_address.s_addr = mreqs.imr_interface;
                                 mreq.imr_ifindex = 0;
                                 err = ip_mc_join_group(sk, &mreq);
-                                if (err)
+                                if (err && err != -EADDRINUSE)
                                         break;
                                 omode = MCAST_INCLUDE;
                                 add = 1;
-                        } else /*IP_DROP_SOURCE_MEMBERSHIP */ {
+                        } else /* IP_DROP_SOURCE_MEMBERSHIP */ {
                                 omode = MCAST_INCLUDE;
                                 add = 0;
                         }
@@ -754,7 +754,7 @@ int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
                                 mreq.imr_address.s_addr = 0;
                                 mreq.imr_ifindex = greqs.gsr_interface;
                                 err = ip_mc_join_group(sk, &mreq);
-                                if (err)
+                                if (err && err != -EADDRINUSE)
                                         break;
                                 greqs.gsr_interface = mreq.imr_ifindex;
                                 omode = MCAST_INCLUDE;