lwn.git/net/ipv6/ip6_offload.c, branch docs-6.12

net: gro: initialize network_offset in network layer

2024-05-27T23:46:59+00:00

Syzkaller was able to trigger kernel BUG at net/core/gro.c:424 ! RIP: 0010:gro_pull_from_frag0 net/core/gro.c:424 [inline] RIP: 0010:gro_try_pull_from_frag0 net/core/gro.c:446 [inline] RIP: 0010:dev_gro_receive+0x242f/0x24b0 net/core/gro.c:571 Due to using an incorrect NAPI_GRO_CB(skb)->network_offset. The referenced commit sets this offset to 0 in skb_gro_reset_offset. That matches the expected case in dev_gro_receive: pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive, ipv6_gro_receive, inet_gro_receive, &gro_list->list, skb); But syzkaller injected an skb with protocol ETH_P_TEB into an ip6gre device (by writing the IP6GRE encapsulated version to a TAP device). The result was a first call to eth_gro_receive, and thus an extra ETH_HLEN in network_offset that should not be there. First issue hit is when computing offset from network header in ipv6_gro_pull_exthdrs. Initialize both offsets in the network layer gro_receive. This pairs with all reads in gro_receive, which use skb_gro_receive_network_offset(). Fixes: 186b1ea73ad8 ("net: gro: use cb instead of skb->network_header") Reported-by: syzkaller Signed-off-by: Willem de Bruijn CC: Richard Gobert Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20240523141434.1752483-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski

net: gro: move L3 flush checks to tcp_gro_receive and udp_gro_receive_segment

2024-05-13T21:44:06+00:00

{inet,ipv6}_gro_receive functions perform flush checks (ttl, flags, iph->id, ...) against all packets in a loop. These flush checks are used in all merging UDP and TCP flows. These checks need to be done only once and only against the found p skb, since they only affect flush and not same_flow. This patch leverages correct network header offsets from the cb for both outer and inner network headers - allowing these checks to be done only once, in tcp_gro_receive and udp_gro_receive_segment. As a result, NAPI_GRO_CB(p)->flush is not used at all. In addition, flush_id checks are more declarative and contained in inet_gro_flush, thus removing the need for flush_id in napi_gro_cb. This results in less parsing code for non-loop flush tests for TCP and UDP flows. To make sure results are not within noise range - I've made netfilter drop all TCP packets, and measured CPU performance in GRO (in this case GRO is responsible for about 50% of the CPU utilization). perf top while replaying 64 parallel IP/TCP streams merging in GRO: (gro_receive_network_flush is compiled inline to tcp_gro_receive) net-next: 6.94% [kernel] [k] inet_gro_receive 3.02% [kernel] [k] tcp_gro_receive patch applied: 4.27% [kernel] [k] tcp_gro_receive 4.22% [kernel] [k] inet_gro_receive perf top while replaying 64 parallel IP/IP/TCP streams merging in GRO (same results for any encapsulation, in this case inet_gro_receive is top offender in net-next) net-next: 10.09% [kernel] [k] inet_gro_receive 2.08% [kernel] [k] tcp_gro_receive patch applied: 6.97% [kernel] [k] inet_gro_receive 3.68% [kernel] [k] tcp_gro_receive Signed-off-by: Richard Gobert Reviewed-by: Willem de Bruijn Link: https://lore.kernel.org/r/20240509190819.2985-3-richardbgobert@gmail.com Signed-off-by: Jakub Kicinski

net: gro: use cb instead of skb->network_header

2024-05-13T21:44:06+00:00

This patch converts references of skb->network_header to napi_gro_cb's network_offset and inner_network_offset. Signed-off-by: Richard Gobert Reviewed-by: Willem de Bruijn Link: https://lore.kernel.org/r/20240509190819.2985-2-richardbgobert@gmail.com Signed-off-by: Jakub Kicinski

net: gro: fix udp bad offset in socket lookup by adding {inner_}network_offset to napi_gro_cb

2024-05-02T09:02:48+00:00

Commits a602456 ("udp: Add GRO functions to UDP socket") and 57c67ff ("udp: additional GRO support") introduce incorrect usage of {ip,ipv6}_hdr in the complete phase of gro. The functions always return skb->network_header, which in the case of encapsulated packets at the gro complete phase, is always set to the innermost L3 of the packet. That means that calling {ip,ipv6}_hdr for skbs which completed the GRO receive phase (both in gro_list and *_gro_complete) when parsing an encapsulated packet's _outer_ L3/L4 may return an unexpected value. This incorrect usage leads to a bug in GRO's UDP socket lookup. udp{4,6}_lib_lookup_skb functions use ip_hdr/ipv6_hdr respectively. These *_hdr functions return network_header which will point to the innermost L3, resulting in the wrong offset being used in __udp{4,6}_lib_lookup with encapsulated packets. This patch adds network_offset and inner_network_offset to napi_gro_cb, and makes sure both are set correctly. To fix the issue, network_offsets union is used inside napi_gro_cb, in which both the outer and the inner network offsets are saved. Reproduction example: Endpoint configuration example (fou + local address bind) # ip fou add port 6666 ipproto 4 # ip link add name tun1 type ipip remote 2.2.2.1 local 2.2.2.2 encap fou encap-dport 5555 encap-sport 6666 mode ipip # ip link set tun1 up # ip a add 1.1.1.2/24 dev tun1 Netperf TCP_STREAM result on net-next before patch is applied: net-next main, GRO enabled: $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5 Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 5.28 2.37 net-next main, GRO disabled: $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5 Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 5.01 2745.06 patch applied, GRO enabled: $ netperf -H 1.1.1.2 -t TCP_STREAM -l 5 Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 5.01 2877.38 Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket") Signed-off-by: Richard Gobert Reviewed-by: Eric Dumazet Reviewed-by: Willem de Bruijn Signed-off-by: Paolo Abeni

net: move ip_packet_offload and ipv6_packet_offload to net_hotdata

2024-03-08T05:12:42+00:00

These structures are used in GRO and GSO paths. v2: ipv6_packet_offload definition depends on CONFIG_INET Signed-off-by: Eric Dumazet Acked-by: Soheil Hassas Yeganeh Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20240306160031.874438-7-edumazet@google.com Signed-off-by: Jakub Kicinski

net: gro: parse ipv6 ext headers without frag0 invalidation

2024-01-05T16:11:49+00:00

The existing code always pulls the IPv6 header and sets the transport offset initially. Then optionally again pulls any extension headers in ipv6_gso_pull_exthdrs and sets the transport offset again on return from that call. skb->data is set at the start of the first extension header before calling ipv6_gso_pull_exthdrs, and must disable the frag0 optimization because that function uses pskb_may_pull/pskb_pull instead of skb_gro_ helpers. It sets the GRO offset to the TCP header with skb_gro_pull and sets the transport header. Then returns skb->data to its position before this block. This commit introduces a new helper function - ipv6_gro_pull_exthdrs - which is used in ipv6_gro_receive to pull ipv6 ext headers instead of ipv6_gso_pull_exthdrs. Thus, there is no modification of skb->data, all operations use skb_gro_* helpers, and the frag0 fast path can be taken for IPv6 packets with ext headers. Signed-off-by: Richard Gobert Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/504130f6-b56c-4dcc-882c-97942c59f5b7@gmail.com Signed-off-by: Jakub Kicinski

net: gso: add HBH extension header offload support

2024-01-05T16:11:49+00:00

This commit adds net_offload to IPv6 Hop-by-Hop extension headers (as it is done for routing and dstopts) since it is supported in GSO and GRO. This allows to remove specific HBH conditionals in GSO and GRO when pulling and parsing an incoming packet. Signed-off-by: Richard Gobert Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/d4f8825a-1d55-4b12-9d67-a254dbbfa6ae@gmail.com Signed-off-by: Jakub Kicinski

net: move gso declarations and functions to their own files

2023-06-10T07:11:41+00:00

Move declarations into include/net/gso.h and code into net/core/gso.c Signed-off-by: Eric Dumazet Cc: Stanislav Fomichev Reviewed-by: Simon Horman Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com Signed-off-by: Jakub Kicinski

IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver

2022-12-12T23:41:44+00:00

IPv6/TCP and GRO stacks can build big TCP packets with an added temporary Hop By Hop header. Is GSO is not involved, then the temporary header needs to be removed in the driver. This patch provides a generic helper for drivers that need to modify their headers in place. Tested: Compiled and ran with ethtool -K eth1 tso off Could send Big TCP packets Signed-off-by: Coco Li Link: https://lore.kernel.org/r/20221210041646.3587757-1-lixiaoyan@google.com Signed-off-by: Jakub Kicinski

net-next: skbuff: refactor pskb_pull

2022-09-30T11:31:46+00:00

pskb_may_pull already contains all of the checks performed by pskb_pull. Use pskb_may_pull for validation in pskb_pull, eliminating the duplication and making __pskb_pull obsolete. Replace __pskb_pull with pskb_pull where applicable. Signed-off-by: Richard Gobert Signed-off-by: David S. Miller