udp: do not transition UDP GRO fraglist partial checksums to unnecessary

commit f0b8c30345565344df2e33a8417a27503589247d upstream.

UDP GRO validates checksums and in udp4/6_gro_complete fraglist packets
are converted to CHECKSUM_UNNECESSARY to avoid later checks. However
this is an issue for CHECKSUM_PARTIAL packets as they can be looped in
an egress path and then their partial checksums are not fixed.

Different issues can be observed, from invalid checksum on packets to
traces like:

  gen01: hw csum failure
  skb len=3008 headroom=160 headlen=1376 tailroom=0
  mac=(106,14) net=(120,40) trans=160
  shinfo(txflags=0 nr_frags=0 gso(size=0 type=0 segs=0))
  csum(0xffff232e ip_summed=2 complete_sw=0 valid=0 level=0)
  hash(0x77e3d716 sw=1 l4=1) proto=0x86dd pkttype=0 iif=12
  ...

Fix this by only converting CHECKSUM_NONE packets to
CHECKSUM_UNNECESSARY by reusing __skb_incr_checksum_unnecessary. All
other checksum types are kept as-is, including CHECKSUM_COMPLETE as
fraglist packets being segmented back would have their skb->csum valid.

Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index a8f4c369ca1158e8db50ddfc7e28df5dc2ad9f3a..90d1b712a66dd971b9ff686c11d236e5d4a5ff9f 100644 (file)
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -685,13 +685,7 @@ INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
                skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
                skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 
-               if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
-                       if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
-                               skb->csum_level++;
-               } else {
-                       skb->ip_summed = CHECKSUM_UNNECESSARY;
-                       skb->csum_level = 0;
-               }
+               __skb_incr_checksum_unnecessary(skb);
 
                return 0;
        }

diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index b3d9ed96e5ea56bf75b8cc10a28027c961a296e9..28f63c01a595398434ee6f4c2609b0606ef369ff 100644 (file)
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -170,13 +170,7 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
                skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
                skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
 
-               if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
-                       if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
-                               skb->csum_level++;
-               } else {
-                       skb->ip_summed = CHECKSUM_UNNECESSARY;
-                       skb->csum_level = 0;
-               }
+               __skb_incr_checksum_unnecessary(skb);
 
                return 0;
        }