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authorDavid L Stevens <dlstevens@us.ibm.com>2005-06-22 00:58:25 +0400
committerDavid S. Miller <davem@davemloft.net>2005-06-22 00:58:25 +0400
commitc9e3e8b6958e02230079e6817862ea2968509866 (patch)
tree296b30b9e208d37b1cdfa6d40ad785abb1487bd9 /net
parent0d51aa80a9b1db43920c0770c3bb842dd823c005 (diff)
downloadlinux-c9e3e8b6958e02230079e6817862ea2968509866.tar.xz
[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 <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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/ipv6_sockglue.c5
-rw-r--r--net/ipv6/mcast.c21
2 files changed, 24 insertions, 2 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 279ab86be662..f3ef4c38d315 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 393b6e6f50a9..c0ca92e8230b 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;
}