[NET]: Fix CHECKSUM_HW GSO problems.
Fix checksum problems in the GSO code path for CHECKSUM_HW packets.
The ipv4 TCP pseudo header checksum has to be adjusted for GSO
segmented packets.
The adjustment is needed because the length field in the pseudo-header
changes. However, because we have the inequality oldlen > newlen, we
know that delta = (u16)~oldlen + newlen is still a 16-bit quantity.
This also means that htonl(delta) + th->check still fits in 32 bits.
Therefore we don't have to use csum_add on this operations.
This is based on a patch by Michael Chan <mchan@broadcom.com>.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0e029c4..c04176b 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2166,7 +2166,7 @@
if (!pskb_may_pull(skb, thlen))
goto out;
- oldlen = ~htonl(skb->len);
+ oldlen = (u16)~skb->len;
__skb_pull(skb, thlen);
segs = skb_segment(skb, sg);
@@ -2174,7 +2174,7 @@
goto out;
len = skb_shinfo(skb)->gso_size;
- delta = csum_add(oldlen, htonl(thlen + len));
+ delta = htonl(oldlen + (thlen + len));
skb = segs;
th = skb->h.th;
@@ -2183,10 +2183,10 @@
do {
th->fin = th->psh = 0;
- if (skb->ip_summed == CHECKSUM_NONE) {
- th->check = csum_fold(csum_partial(
- skb->h.raw, thlen, csum_add(skb->csum, delta)));
- }
+ th->check = ~csum_fold(th->check + delta);
+ if (skb->ip_summed != CHECKSUM_HW)
+ th->check = csum_fold(csum_partial(skb->h.raw, thlen,
+ skb->csum));
seq += len;
skb = skb->next;
@@ -2196,11 +2196,11 @@
th->cwr = 0;
} while (skb->next);
- if (skb->ip_summed == CHECKSUM_NONE) {
- delta = csum_add(oldlen, htonl(skb->tail - skb->h.raw));
- th->check = csum_fold(csum_partial(
- skb->h.raw, thlen, csum_add(skb->csum, delta)));
- }
+ delta = htonl(oldlen + (skb->tail - skb->h.raw) + skb->data_len);
+ th->check = ~csum_fold(th->check + delta);
+ if (skb->ip_summed != CHECKSUM_HW)
+ th->check = csum_fold(csum_partial(skb->h.raw, thlen,
+ skb->csum));
out:
return segs;