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| author | Yuchung Cheng <ycheng@google.com> | 2017-05-10 17:01:27 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-05-11 21:35:20 -0400 |
| commit | b451e5d24ba6687c6f0e7319c727a709a1846c06 (patch) | |
| tree | 6c608e72316408de39225799630de48ee6d0509c /net | |
| parent | f6ba8d33cfbb46df569972e64dbb5bb7e929bfd9 (diff) | |
| download | linux-stable-b451e5d24ba6687c6f0e7319c727a709a1846c06.tar.gz linux-stable-b451e5d24ba6687c6f0e7319c727a709a1846c06.tar.bz2 linux-stable-b451e5d24ba6687c6f0e7319c727a709a1846c06.zip | |
tcp: avoid fragmenting peculiar skbs in SACK
This patch fixes a bug in splitting an SKB during SACK
processing. Specifically if an skb contains multiple
packets and is only partially sacked in the higher sequences,
tcp_match_sack_to_skb() splits the skb and marks the second fragment
as SACKed.
The current code further attempts rounding up the first fragment
to MSS boundaries. But it misses a boundary condition when the
rounded-up fragment size (pkt_len) is exactly skb size. Spliting
such an skb is pointless and causses a kernel warning and aborts
the SACK processing. This patch universally checks such over-split
before calling tcp_fragment to prevent these unnecessary warnings.
Fixes: adb92db857ee ("tcp: Make SACK code to split only at mss boundaries")
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_input.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 5a3ad09e2786..06e2dbc2b4a2 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1179,13 +1179,14 @@ static int tcp_match_skb_to_sack(struct sock *sk, struct sk_buff *skb, */ if (pkt_len > mss) { unsigned int new_len = (pkt_len / mss) * mss; - if (!in_sack && new_len < pkt_len) { + if (!in_sack && new_len < pkt_len) new_len += mss; - if (new_len >= skb->len) - return 0; - } pkt_len = new_len; } + + if (pkt_len >= skb->len && !in_sack) + return 0; + err = tcp_fragment(sk, skb, pkt_len, mss, GFP_ATOMIC); if (err < 0) return err; |