From 912d398d28b4359c2fb1f3763f1ce4f86de8350e Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Wed, 6 Apr 2011 18:40:12 +0000 Subject: [PATCH] net: fix skb_add_data_nocache() to calc csum correctly commit c6e1a0d12ca7b4f22c58e55a16beacfb7d3d8462 broken the calc (net: Allow no-cache copy from user on transmit) of checksum, which may cause some tcp packets be dropped because incorrect checksum. ssh does not work under today's net-next-2.6 tree. Signed-off-by: Wei Yongjun Acked-by: Tom Herbert Signed-off-by: David S. Miller --- include/net/sock.h | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 43bd515e92f..9cbf23c815f 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1392,14 +1392,14 @@ static inline void sk_nocaps_add(struct sock *sk, int flags) static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb, char __user *from, char *to, - int copy) + int copy, int offset) { if (skb->ip_summed == CHECKSUM_NONE) { int err = 0; __wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err); if (err) return err; - skb->csum = csum_block_add(skb->csum, csum, skb->len); + skb->csum = csum_block_add(skb->csum, csum, offset); } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) { if (!access_ok(VERIFY_READ, from, copy) || __copy_from_user_nocache(to, from, copy)) @@ -1413,11 +1413,12 @@ static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb, static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb, char __user *from, int copy) { - int err; + int err, offset = skb->len; - err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy), copy); + err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy), + copy, offset); if (err) - __skb_trim(skb, skb->len); + __skb_trim(skb, offset); return err; } @@ -1429,8 +1430,8 @@ static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from, { int err; - err = skb_do_copy_data_nocache(sk, skb, from, - page_address(page) + off, copy); + err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off, + copy, skb->len); if (err) return err;