af_packet: don't emit packet on orig fanout group
authorEric Leblond <eric@regit.org>
Thu, 16 Aug 2012 22:02:58 +0000 (22:02 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 2 Oct 2012 17:29:37 +0000 (10:29 -0700)
commit9e296becde8a8da5bcc1a8e22f27bdf9bd8636fe
treebe7a8a0b16cb84b2781b7e210e9749b8236092db
parentd09b3b2b1183848e287bc0b6397f8d05945becc4
af_packet: don't emit packet on orig fanout group

[ Upstream commit c0de08d04215031d68fa13af36f347a6cfa252ca ]

If a packet is emitted on one socket in one group of fanout sockets,
it is transmitted again. It is thus read again on one of the sockets
of the fanout group. This result in a loop for software which
generate packets when receiving one.
This retransmission is not the intended behavior: a fanout group
must behave like a single socket. The packet should not be
transmitted on a socket if it originates from a socket belonging
to the same fanout group.

This patch fixes the issue by changing the transmission check to
take fanout group info account.

Reported-by: Aleksandr Kotov <a1k@mail.ru>
Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
include/linux/netdevice.h
net/core/dev.c
net/packet/af_packet.c