diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-11-02 22:30:25 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-11-03 08:29:01 +0300 |
| commit | 3b11775033dc87c3d161996c54507b15ba26414a (patch) | |
| tree | 01e52ff98514d77a36116f02f3745b1bce20d519 | |
| parent | 25dd169aea6553aea548197a5d4580bbdeda1c85 (diff) | |
| download | linux-3b11775033dc87c3d161996c54507b15ba26414a.tar.xz | |
tcp: do not mangle skb->cb[] in tcp_make_synack()
Christoph Paasch sent a patch to address the following issue :
tcp_make_synack() is leaving some TCP private info in skb->cb[],
then send the packet by other means than tcp_transmit_skb()
tcp_transmit_skb() makes sure to clear skb->cb[] to not confuse
IPv4/IPV6 stacks, but we have no such cleanup for SYNACK.
tcp_make_synack() should not use tcp_init_nondata_skb() :
tcp_init_nondata_skb() really should be limited to skbs put in write/rtx
queues (the ones that are only sent via tcp_transmit_skb())
This patch fixes the issue and should even save few cpu cycles ;)
Fixes: 971f10eca186 ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_output.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 823003eef3a2..478909f4694d 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3180,13 +3180,8 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, th->source = htons(ireq->ir_num); th->dest = ireq->ir_rmt_port; skb->mark = ireq->ir_mark; - /* Setting of flags are superfluous here for callers (and ECE is - * not even correctly set) - */ - tcp_init_nondata_skb(skb, tcp_rsk(req)->snt_isn, - TCPHDR_SYN | TCPHDR_ACK); - - th->seq = htonl(TCP_SKB_CB(skb)->seq); + skb->ip_summed = CHECKSUM_PARTIAL; + th->seq = htonl(tcp_rsk(req)->snt_isn); /* XXX data is queued and acked as is. No buffer/window check */ th->ack_seq = htonl(tcp_rsk(req)->rcv_nxt); |