bridge: fix igmpv3 / mldv2 report parsing
bridge: fix igmpv3 / mldv2 report parsing

With the newly introduced helper functions the skb pulling is hidden in
the checksumming function - and undone before returning to the caller.

The IGMPv3 and MLDv2 report parsing functions in the bridge still
assumed that the skb is pointing to the beginning of the IGMP/MLD
message while it is now kept at the beginning of the IPv4/6 header,
breaking the message parsing and creating packet loss.

Fixing this by taking the offset between IP and IGMP/MLD header into
account, too.

Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code")
Reported-by: Tobias Powalowski <12e798294e1aa5ad03ec94aa630e84d7b2b8a082@googlemail.com>
Tested-by: Tobias Powalowski <12e798294e1aa5ad03ec94aa630e84d7b2b8a082@googlemail.com>
Signed-off-by: Linus Lüssing <1dd561f221e05f08425aa0351cbf66864fb4804d@c0d3.blue>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs