queue-6.1/udp-do-not-transition-udp-gro-fraglist-partial-checksums-to-unnecessary.patch

   1 From f0b8c30345565344df2e33a8417a27503589247d Mon Sep 17 00:00:00 2001
   2 From: Antoine Tenart <atenart@kernel.org>
   3 Date: Tue, 26 Mar 2024 12:34:00 +0100
   4 Subject: udp: do not transition UDP GRO fraglist partial checksums to unnecessary
   5
   6 From: Antoine Tenart <atenart@kernel.org>
   7
   8 commit f0b8c30345565344df2e33a8417a27503589247d upstream.
   9
  10 UDP GRO validates checksums and in udp4/6_gro_complete fraglist packets
  11 are converted to CHECKSUM_UNNECESSARY to avoid later checks. However
  12 this is an issue for CHECKSUM_PARTIAL packets as they can be looped in
  13 an egress path and then their partial checksums are not fixed.
  14
  15 Different issues can be observed, from invalid checksum on packets to
  16 traces like:
  17
  18   gen01: hw csum failure
  19   skb len=3008 headroom=160 headlen=1376 tailroom=0
  20   mac=(106,14) net=(120,40) trans=160
  21   shinfo(txflags=0 nr_frags=0 gso(size=0 type=0 segs=0))
  22   csum(0xffff232e ip_summed=2 complete_sw=0 valid=0 level=0)
  23   hash(0x77e3d716 sw=1 l4=1) proto=0x86dd pkttype=0 iif=12
  24   ...
  25
  26 Fix this by only converting CHECKSUM_NONE packets to
  27 CHECKSUM_UNNECESSARY by reusing __skb_incr_checksum_unnecessary. All
  28 other checksum types are kept as-is, including CHECKSUM_COMPLETE as
  29 fraglist packets being segmented back would have their skb->csum valid.
  30
  31 Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
  32 Signed-off-by: Antoine Tenart <atenart@kernel.org>
  33 Reviewed-by: Willem de Bruijn <willemb@google.com>
  34 Signed-off-by: David S. Miller <davem@davemloft.net>
  35 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  36 ---
  37  net/ipv4/udp_offload.c |    8 +-------
  38  net/ipv6/udp_offload.c |    8 +-------
  39  2 files changed, 2 insertions(+), 14 deletions(-)
  40
  41 --- a/net/ipv4/udp_offload.c
  42 +++ b/net/ipv4/udp_offload.c
  43 @@ -710,13 +710,7 @@ INDIRECT_CALLABLE_SCOPE int udp4_gro_com
  44                 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
  45                 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
  46
  47 -               if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
  48 -                       if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
  49 -                               skb->csum_level++;
  50 -               } else {
  51 -                       skb->ip_summed = CHECKSUM_UNNECESSARY;
  52 -                       skb->csum_level = 0;
  53 -               }
  54 +               __skb_incr_checksum_unnecessary(skb);
  55
  56                 return 0;
  57         }
  58 --- a/net/ipv6/udp_offload.c
  59 +++ b/net/ipv6/udp_offload.c
  60 @@ -169,13 +169,7 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_com
  61                 skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
  62                 skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
  63
  64 -               if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
  65 -                       if (skb->csum_level < SKB_MAX_CSUM_LEVEL)
  66 -                               skb->csum_level++;
  67 -               } else {
  68 -                       skb->ip_summed = CHECKSUM_UNNECESSARY;
  69 -                       skb->csum_level = 0;
  70 -               }
  71 +               __skb_incr_checksum_unnecessary(skb);
  72
  73                 return 0;
  74         }