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| author | Eric Dumazet <edumazet@google.com> | 2015-06-03 23:49:21 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-06-04 01:04:40 -0700 |
| commit | 12e25e1041d044d4204f2b7c54695e14e8ffb282 (patch) | |
| tree | 9ebfb1b3d4ba5a1c6bca7c66ee2454686e2a25d2 | |
| parent | 37c8e2b069c7ccff3ff6a356f82ed11abab5fb99 (diff) | |
| download | linux-12e25e1041d044d4204f2b7c54695e14e8ffb282.tar.gz linux-12e25e1041d044d4204f2b7c54695e14e8ffb282.tar.bz2 linux-12e25e1041d044d4204f2b7c54695e14e8ffb282.zip | |
tcp: remove redundant checks
tcp_v4_rcv() checks the following before calling tcp_v4_do_rcv():
if (th->doff < sizeof(struct tcphdr) / 4)
goto bad_packet;
if (!pskb_may_pull(skb, th->doff * 4))
goto discard_it;
So following check in tcp_v4_do_rcv() is redundant
and "goto csum_err;" is wrong anyway.
if (skb->len < tcp_hdrlen(skb) || ...)
goto csum_err;
A second check can be removed after no_tcp_socket label for same reason.
Same tests can be removed in tcp_v6_do_rcv()
Note : short tcp frames are not properly accounted in tcpInErrs MIB,
because pskb_may_pull() failure simply drops incoming skb, we might
fix this in a separate patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 4 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index feb875769b8d..3130c42240c8 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1400,7 +1400,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) return 0; } - if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb)) + if (tcp_checksum_complete(skb)) goto csum_err; if (sk->sk_state == TCP_LISTEN) { @@ -1647,7 +1647,7 @@ no_tcp_socket: if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) goto discard_it; - if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) { + if (tcp_checksum_complete(skb)) { csum_error: TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS); bad_packet: diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7be3d858cbf0..b72e1ffc6bb4 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1250,7 +1250,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) return 0; } - if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb)) + if (tcp_checksum_complete(skb)) goto csum_err; if (sk->sk_state == TCP_LISTEN) { @@ -1442,7 +1442,7 @@ no_tcp_socket: tcp_v6_fill_cb(skb, hdr, th); - if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) { + if (tcp_checksum_complete(skb)) { csum_error: TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS); bad_packet: |