[NET]: Detect hardware rx checksum faults correctly
Here is the patch that introduces the generic skb_checksum_complete
which also checks for hardware RX checksum faults. If that happens,
it'll call netdev_rx_csum_fault which currently prints out a stack
trace with the device name. In future it can turn off RX checksum.
I've converted every spot under net/ that does RX checksum checks to
use skb_checksum_complete or __skb_checksum_complete with the
exceptions of:
* Those places where checksums are done bit by bit. These will call
netdev_rx_csum_fault directly.
* The following have not been completely checked/converted:
ipmr
ip_vs
netfilter
dccp
This patch is based on patches and suggestions from Stephen Hemminger
and David S. Miller.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 634dabb..ac1fcf5 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1110,24 +1110,18 @@
static int tcp_v4_checksum_init(struct sk_buff *skb)
{
if (skb->ip_summed == CHECKSUM_HW) {
- skb->ip_summed = CHECKSUM_UNNECESSARY;
if (!tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
- skb->nh.iph->daddr, skb->csum))
+ skb->nh.iph->daddr, skb->csum)) {
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
return 0;
-
- LIMIT_NETDEBUG(KERN_DEBUG "hw tcp v4 csum failed\n");
- skb->ip_summed = CHECKSUM_NONE;
+ }
}
+
+ skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr, skb->nh.iph->daddr,
+ skb->len, IPPROTO_TCP, 0);
+
if (skb->len <= 76) {
- if (tcp_v4_check(skb->h.th, skb->len, skb->nh.iph->saddr,
- skb->nh.iph->daddr,
- skb_checksum(skb, 0, skb->len, 0)))
- return -1;
- skb->ip_summed = CHECKSUM_UNNECESSARY;
- } else {
- skb->csum = ~tcp_v4_check(skb->h.th, skb->len,
- skb->nh.iph->saddr,
- skb->nh.iph->daddr, 0);
+ return __skb_checksum_complete(skb);
}
return 0;
}
@@ -1219,7 +1213,7 @@
* provided case of th->doff==0 is elimineted.
* So, we defer the checks. */
if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
- tcp_v4_checksum_init(skb) < 0))
+ tcp_v4_checksum_init(skb)))
goto bad_packet;
th = skb->h.th;