[DCCP]: Fix skb->cb conflicts with IP
authorPatrick McHardy <kaber@trash.net>
Sun, 13 Apr 2008 01:35:41 +0000 (18:35 -0700)
committerDavid S. Miller <davem@davemloft.net>
Sun, 13 Apr 2008 01:35:41 +0000 (18:35 -0700)
commit028b027524b162eef90839a92ba4b8bddf23e06c
tree5c128717f73ff6fb93c361cfae6961267ed52082
parentae1b6a31b1f9ef2c7ba5ef89799f210a9ba6937c
[DCCP]: Fix skb->cb conflicts with IP

dev_queue_xmit() and the other IP output functions expect to get a skb
with clear or properly initialized skb->cb. Unlike TCP and UDP, the
dccp_skb_cb doesn't contain a struct inet_skb_parm at the beginning,
so the DCCP-specific data is interpreted by the IP output functions.
This can cause false negatives for the conditional POST_ROUTING hook
invocation, making the packet bypass the hook.

Add a inet_skb_parm/inet6_skb_parm union to the beginning of
dccp_skb_cb to avoid clashes. Also add a BUILD_BUG_ON to make
sure it fits in the cb.

[ Combined with patch from Gerrit Renker to remove two now unnecessary
  memsets of IPCB(skb)->opt ]

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dccp/dccp.h
net/dccp/ipv4.c
net/dccp/output.c
net/dccp/proto.c