[Bridge] [PATCH 2/2] bridge: Use IPv6 link-local address for multicast listener queries

[Bridge] [PATCH 2/2] bridge: Use IPv6 link-local address for multicast listener queries

[Satya Narayana]

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Hello,

I am using 2.6.39.4 kernel for MLD snooping, in net/bridge/br_multicast.c
file,

we observed the check for tranoisent flag in the group address.

 That mean with out this flag set the group address will be droped.

 My doubt is why MLD is restricted with T (transient) flag, we can't use
with out T flag multicast group address.

 Looking forward for you replay, Thank you in advance.


Regards,

Satya

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Re: [Bridge] [PATCH 2/2] bridge: Use IPv6 link-local address for multicast listener queries

[David Miller]

From: Linus Lüssing <linus.luessing@web.de>
Date: Thu, 17 Feb 2011 19:17:52 +0100

> Currently the bridge multicast snooping feature periodically issues
> IPv6 general multicast listener queries to sense the absence of a
> listener.
> 
> For this, it uses :: as its source address - however RFC 2710 requires:
> "To be valid, the Query message MUST come from a link-local IPv6 Source
> Address". Current Linux kernel versions seem to follow this requirement
> and ignore our bogus MLD queries.
> 
> With this commit a link local address from the bridge interface is being
> used to issue the MLD query, resulting in other Linux devices which are
> multicast listeners in the network to respond with a MLD response (which
> was not the case before).
> 
> Signed-off-by: Linus Lüssing <linus.luessing@web.de>

Applied.

[Bridge] [PATCH 2/2] bridge: Use IPv6 link-local address for multicast listener queries

[Linus Lüssing]

Currently the bridge multicast snooping feature periodically issues
IPv6 general multicast listener queries to sense the absence of a
listener.

For this, it uses :: as its source address - however RFC 2710 requires:
"To be valid, the Query message MUST come from a link-local IPv6 Source
Address". Current Linux kernel versions seem to follow this requirement
and ignore our bogus MLD queries.

With this commit a link local address from the bridge interface is being
used to issue the MLD query, resulting in other Linux devices which are
multicast listeners in the network to respond with a MLD response (which
was not the case before).

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
 net/bridge/br_multicast.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index f904a2e..2d88861 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -446,7 +446,8 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 	ip6h->payload_len = htons(8 + sizeof(*mldq));
 	ip6h->nexthdr = IPPROTO_HOPOPTS;
 	ip6h->hop_limit = 1;
-	ipv6_addr_set(&ip6h->saddr, 0, 0, 0, 0);
+	ipv6_dev_get_saddr(dev_net(br->dev), br->dev, &ip6h->daddr, 0,
+			   &ip6h->saddr);
 	ipv6_addr_set(&ip6h->daddr, htonl(0xff020000), 0, 0, htonl(1));
 	ipv6_eth_mc_map(&ip6h->daddr, eth->h_dest);
 
-- 
1.7.2.3