From: Herbert Xu Date: Thu, 29 Nov 2007 12:07:58 +0000 (+1100) Subject: TCP: Fix TCP header misalignment X-Git-Tag: v2.6.23.10~17 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=593b85eff26bc1c33c54be8632ac181b6cc1b5a4;p=thirdparty%2Fkernel%2Fstable.git TCP: Fix TCP header misalignment [TCP]: Fix TCP header misalignment [ Upstream commit: 21df56c6e2372e09c916111efb6c14c372a5ab2e ] Indeed my previous change to alloc_pskb has made it possible for the TCP header to be misaligned iff the MTU is not a multiple of 4 (and less than a page). So I suspect the optimised IPsec MTU calculation is giving you just such an MTU :) This patch fixes it by changing alloc_pskb to make sure that the size is at least 32-bit aligned. This does not cause the problem fixed by the previous patch because max_header is always 32-bit aligned which means that in the SG/NOTSO case this will be a no-op. I thought about putting this in the callers but all the current callers are from TCP. If and when we get a non-TCP caller we can always create a TCP wrapper for this function and move the alignment over there. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/net/sock.h b/include/net/sock.h index bdd9ebe633928..8a71ab3626122 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1200,6 +1200,9 @@ static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk, { struct sk_buff *skb; + /* The TCP header must be at least 32-bit aligned. */ + size = ALIGN(size, 4); + skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); if (skb) { skb->truesize += mem;