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[35.194.87.55]) by smtp.gmail.com with ESMTPSA id bk31-20020a05620a1a1f00b00789ea49fd22sm13440qkb.49.2024.03.22.10.29.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Mar 2024 10:29:40 -0700 (PDT) Date: Fri, 22 Mar 2024 13:29:40 -0400 From: Willem de Bruijn To: Antoine Tenart , davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com Cc: Antoine Tenart , steffen.klassert@secunet.com, willemdebruijn.kernel@gmail.com, netdev@vger.kernel.org Message-ID: <65fdc00454e16_2bd0fb2948c@willemb.c.googlers.com.notmuch> In-Reply-To: <20240322114624.160306-4-atenart@kernel.org> References: <20240322114624.160306-1-atenart@kernel.org> <20240322114624.160306-4-atenart@kernel.org> Subject: Re: [PATCH net v3 3/4] udp: do not transition UDP GRO fraglist partial checksums to unnecessary Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Antoine Tenart wrote: > 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. > > Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") > Signed-off-by: Antoine Tenart Sorry to have yet more questions, but Should fraglist UDP GRO and non-fraglist (udp_gro_complete_segment) have the same checksumming behavior? Second, this leaves CHECKSUM_COMPLETE as is. Is that intentional? I don't immediately see where GSO skb->csum would be updated. I can take a closer look too, but did not want to delay feedback. > --- > net/ipv4/udp_offload.c | 8 +------- > net/ipv6/udp_offload.c | 8 +------- > 2 files changed, 2 insertions(+), 14 deletions(-) > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 3bb69464930b..548476d78237 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -722,13 +722,7 @@ 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 312bcaeea96f..bbd347de00b4 100644 > --- a/net/ipv6/udp_offload.c > +++ b/net/ipv6/udp_offload.c > @@ -174,13 +174,7 @@ 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; > } > -- > 2.44.0 >