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[IPV6]: multicast join and misc

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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 <hoerdt@clarinet.u-strasbg.fr> who
reported the original bug.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David L Stevens
2005-06-21 13:58:25 -07:00
committed by David S. Miller
parent 0d51aa80a9
commit c9e3e8b695
2 changed files with 24 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
net/ipv6/ipv6_sockglue.c
View File

@@ -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;
}