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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-12-04 08:51:08 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-12-05 23:30:03 (GMT) |
| commit | 4fa48bf3c75069d636fc8830743c929a062e80dc (patch) | |
| tree | 3fe5e488ee6ac1af1b76497a5e6281106a8b2d2e | |
| parent | 7d3113042823344dcc175b0ea00a83d0273c98a4 (diff) | |
| download | linux-4fa48bf3c75069d636fc8830743c929a062e80dc.tar.xz | |
tcp: fix tcp_trim_head()
commit f07d960df3 (tcp: avoid frag allocation for small frames)
breaked assumption in tcp stack that skb is either linear (skb->data_len
== 0), or fully fragged (skb->data_len == skb->len)
tcp_trim_head() made this assumption, we must fix it.
Thanks to Vijay for providing a very detailed explanation.
Reported-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_output.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 50788d6..cf30680 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1093,6 +1093,13 @@ static void __pskb_trim_head(struct sk_buff *skb, int len) { int i, k, eat; + eat = min_t(int, len, skb_headlen(skb)); + if (eat) { + __skb_pull(skb, eat); + len -= eat; + if (!len) + return; + } eat = len; k = 0; for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { @@ -1124,11 +1131,7 @@ int tcp_trim_head(struct sock *sk, struct sk_buff *skb, u32 len) if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) return -ENOMEM; - /* If len == headlen, we avoid __skb_pull to preserve alignment. */ - if (unlikely(len < skb_headlen(skb))) - __skb_pull(skb, len); - else - __pskb_trim_head(skb, len - skb_headlen(skb)); + __pskb_trim_head(skb, len); TCP_SKB_CB(skb)->seq += len; skb->ip_summed = CHECKSUM_PARTIAL; |