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 <yjwei@cn.fujitsu.com>
Acked-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index 43bd515..9cbf23c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1392,14 +1392,14 @@
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_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 @@
{
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;