summaryrefslogtreecommitdiff
path: root/net/ipv4/tcp_offload.c
AgeCommit message (Collapse)Author
2025-05-01net: use sock_gen_put() when sk_state is TCP_TIME_WAITJibin Zhang
It is possible for a pointer of type struct inet_timewait_sock to be returned from the functions __inet_lookup_established() and __inet6_lookup_established(). This can cause a crash when the returned pointer is of type struct inet_timewait_sock and sock_put() is called on it. The following is a crash call stack that shows sk->sk_wmem_alloc being accessed in sk_free() during the call to sock_put() on a struct inet_timewait_sock pointer. To avoid this issue, use sock_gen_put() instead of sock_put() when sk->sk_state is TCP_TIME_WAIT. mrdump.ko ipanic() + 120 vmlinux notifier_call_chain(nr_to_call=-1, nr_calls=0) + 132 vmlinux atomic_notifier_call_chain(val=0) + 56 vmlinux panic() + 344 vmlinux add_taint() + 164 vmlinux end_report() + 136 vmlinux kasan_report(size=0) + 236 vmlinux report_tag_fault() + 16 vmlinux do_tag_recovery() + 16 vmlinux __do_kernel_fault() + 88 vmlinux do_bad_area() + 28 vmlinux do_tag_check_fault() + 60 vmlinux do_mem_abort() + 80 vmlinux el1_abort() + 56 vmlinux el1h_64_sync_handler() + 124 vmlinux > 0xFFFFFFC080011294() vmlinux __lse_atomic_fetch_add_release(v=0xF2FFFF82A896087C) vmlinux __lse_atomic_fetch_sub_release(v=0xF2FFFF82A896087C) vmlinux arch_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C) + 8 vmlinux raw_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C) + 8 vmlinux atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C) + 8 vmlinux __refcount_sub_and_test(i=1, r=0xF2FFFF82A896087C, oldp=0) + 8 vmlinux __refcount_dec_and_test(r=0xF2FFFF82A896087C, oldp=0) + 8 vmlinux refcount_dec_and_test(r=0xF2FFFF82A896087C) + 8 vmlinux sk_free(sk=0xF2FFFF82A8960700) + 28 vmlinux sock_put() + 48 vmlinux tcp6_check_fraglist_gro() + 236 vmlinux tcp6_gro_receive() + 624 vmlinux ipv6_gro_receive() + 912 vmlinux dev_gro_receive() + 1116 vmlinux napi_gro_receive() + 196 ccmni.ko ccmni_rx_callback() + 208 ccmni.ko ccmni_queue_recv_skb() + 388 ccci_dpmaif.ko dpmaif_rxq_push_thread() + 1088 vmlinux kthread() + 268 vmlinux 0xFFFFFFC08001F30C() Fixes: c9d1d23e5239 ("net: add heuristic for enabling TCP fraglist GRO") Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com> Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Link: https://patch.msgid.link/20250429020412.14163-1-shiming.cheng@mediatek.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-17gro: prevent ACE field corruption & better AccECN handlingIlpo Järvinen
There are important differences in how the CWR field behaves in RFC3168 and AccECN. With AccECN, CWR flag is part of the ACE counter and its changes are important so adjust the flags changed mask accordingly. Also, if CWR is there, set the Accurate ECN GSO flag to avoid corrupting CWR flag somewhere. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17gso: AccECN supportIlpo Järvinen
Handling the CWR flag differs between RFC 3168 ECN and AccECN. With RFC 3168 ECN aware TSO (NETIF_F_TSO_ECN) CWR flag is cleared starting from 2nd segment which is incompatible how AccECN handles the CWR flag. Such super-segments are indicated by SKB_GSO_TCP_ECN. With AccECN, CWR flag (or more accurately, the ACE field that also includes ECE & AE flags) changes only when new packet(s) with CE mark arrives so the flag should not be changed within a super-skb. The new skb/feature flags are necessary to prevent such TSO engines corrupting AccECN ACE counters by clearing the CWR flag (if the CWR handling feature cannot be turned off). If NIC is completely unaware of RFC3168 ECN (doesn't support NETIF_F_TSO_ECN) or its TSO engine can be set to not touch CWR flag despite supporting also NETIF_F_TSO_ECN, TSO could be safely used with AccECN on such NIC. This should be evaluated per NIC basis (not done in this patch series for any NICs). For the cases, where TSO cannot keep its hands off the CWR flag, a GSO fallback is provided by this patch. Signed-off-by: Ilpo Järvinen <ij@kernel.org> Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.14-rc6). Conflicts: net/ethtool/cabletest.c 2bcf4772e45a ("net: ethtool: try to protect all callback with netdev instance lock") 637399bf7e77 ("net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device") No Adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-05net-timestamp: support TCP GSO case for a few missing flagsJason Xing
When I read through the TSO codes, I found out that we probably miss initializing the tx_flags of last seg when TSO is turned off, which means at the following points no more timestamp (for this last one) will be generated. There are three flags to be handled in this patch: 1. SKBTX_HW_TSTAMP 2. SKBTX_BPF 3. SKBTX_SCHED_TSTAMP Note that SKBTX_BPF[1] was added in 6.14.0-rc2 by commit 6b98ec7e882af ("bpf: Add BPF_SOCK_OPS_TSTAMP_SCHED_CB callback") and only belongs to net-next branch material for now. The common issue of the above three flags can be fixed by this single patch. This patch initializes the tx_flags to SKBTX_ANY_TSTAMP like what the UDP GSO does to make the newly segmented last skb inherit the tx_flags so that requested timestamp will be generated in each certain layer, or else that last one has zero value of tx_flags which leads to no timestamp at all. Fixes: 4ed2d765dfacc ("net-timestamp: TCP timestamping") Signed-off-by: Jason Xing <kerneljasonxing@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-03net: gro: convert four dev_net() callsEric Dumazet
tcp4_check_fraglist_gro(), tcp6_check_fraglist_gro(), udp4_gro_lookup_skb() and udp6_gro_lookup_skb() assume RCU is held so that the net structure does not disappear. Use dev_net_rcu() instead of dev_net() to get LOCKDEP support. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250301201424.2046477-5-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-02net: gso: fix tcp fraglist segmentation after pull from frag_listFelix Fietkau
Detect tcp gso fraglist skbs with corrupted geometry (see below) and pass these to skb_segment instead of skb_segment_list, as the first can segment them correctly. Valid SKB_GSO_FRAGLIST skbs - consist of two or more segments - the head_skb holds the protocol headers plus first gso_size - one or more frag_list skbs hold exactly one segment - all but the last must be gso_size Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can modify these skbs, breaking these invariants. In extreme cases they pull all data into skb linear. For TCP, this causes a NULL ptr deref in __tcpv4_gso_segment_list_csum at tcp_hdr(seg->next). Detect invalid geometry due to pull, by checking head_skb size. Don't just drop, as this may blackhole a destination. Convert to be able to pass to regular skb_segment. Approach and description based on a patch by Willem de Bruijn. Link: https://lore.kernel.org/netdev/20240428142913.18666-1-shiming.cheng@mediatek.com/ Link: https://lore.kernel.org/netdev/20240922150450.3873767-1-willemdebruijn.kernel@gmail.com/ Fixes: bee88cd5bd83 ("net: add support for segmenting TCP fraglist GSO packets") Cc: stable@vger.kernel.org Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20240926085315.51524-1-nbd@nbd.name Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-07-30net: drop bad gso csum_start and offset in virtio_net_hdrWillem de Bruijn
Tighten csum_start and csum_offset checks in virtio_net_hdr_to_skb for GSO packets. The function already checks that a checksum requested with VIRTIO_NET_HDR_F_NEEDS_CSUM is in skb linear. But for GSO packets this might not hold for segs after segmentation. Syzkaller demonstrated to reach this warning in skb_checksum_help offset = skb_checksum_start_offset(skb); ret = -EINVAL; if (WARN_ON_ONCE(offset >= skb_headlen(skb))) By injecting a TSO packet: WARNING: CPU: 1 PID: 3539 at net/core/dev.c:3284 skb_checksum_help+0x3d0/0x5b0 ip_do_fragment+0x209/0x1b20 net/ipv4/ip_output.c:774 ip_finish_output_gso net/ipv4/ip_output.c:279 [inline] __ip_finish_output+0x2bd/0x4b0 net/ipv4/ip_output.c:301 iptunnel_xmit+0x50c/0x930 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x2296/0x2c70 net/ipv4/ip_tunnel.c:813 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x759/0xa60 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4850 [inline] netdev_start_xmit include/linux/netdevice.h:4864 [inline] xmit_one net/core/dev.c:3595 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3611 __dev_queue_xmit+0x1b97/0x3c90 net/core/dev.c:4261 packet_snd net/packet/af_packet.c:3073 [inline] The geometry of the bad input packet at tcp_gso_segment: [ 52.003050][ T8403] skb len=12202 headroom=244 headlen=12093 tailroom=0 [ 52.003050][ T8403] mac=(168,24) mac_len=24 net=(192,52) trans=244 [ 52.003050][ T8403] shinfo(txflags=0 nr_frags=1 gso(size=1552 type=3 segs=0)) [ 52.003050][ T8403] csum(0x60000c7 start=199 offset=1536 ip_summed=3 complete_sw=0 valid=0 level=0) Mitigate with stricter input validation. csum_offset: for GSO packets, deduce the correct value from gso_type. This is already done for USO. Extend it to TSO. Let UFO be: udp[46]_ufo_fragment ignores these fields and always computes the checksum in software. csum_start: finding the real offset requires parsing to the transport header. Do not add a parser, use existing segmentation parsing. Thanks to SKB_GSO_DODGY, that also catches bad packets that are hw offloaded. Again test both TSO and USO. Do not test UFO for the above reason, and do not test UDP tunnel offload. GSO packet are almost always CHECKSUM_PARTIAL. USO packets may be CHECKSUM_NONE since commit 10154dbded6d6 ("udp: Allow GSO transmit from devices with no checksum offload"), but then still these fields are initialized correctly in udp4_hwcsum/udp6_hwcsum_outgoing. So no need to test for ip_summed == CHECKSUM_PARTIAL first. This revises an existing fix mentioned in the Fixes tag, which broke small packets with GSO offload, as detected by kselftests. Link: https://syzkaller.appspot.com/bug?extid=e1db31216c789f552871 Link: https://lore.kernel.org/netdev/20240723223109.2196886-1-kuba@kernel.org Fixes: e269d79c7d35 ("net: missing check virtio") Cc: stable@vger.kernel.org Signed-off-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20240729201108.1615114-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-05-13net: gro: move L3 flush checks to tcp_gro_receive and udp_gro_receive_segmentRichard Gobert
{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 <richardbgobert@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20240509190819.2985-3-richardbgobert@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-05-13net: gro: use cb instead of skb->network_headerRichard Gobert
This patch converts references of skb->network_header to napi_gro_cb's network_offset and inner_network_offset. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20240509190819.2985-2-richardbgobert@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-05-06net: add heuristic for enabling TCP fraglist GROFelix Fietkau
When forwarding TCP after GRO, software segmentation is very expensive, especially when the checksum needs to be recalculated. One case where that's currently unavoidable is when routing packets over PPPoE. Performance improves significantly when using fraglist GRO implemented in the same way as for UDP. When NETIF_F_GRO_FRAGLIST is enabled, perform a lookup for an established socket in the same netns as the receiving device. While this may not cover all relevant use cases in multi-netns configurations, it should be good enough for most configurations that need this. Here's a measurement of running 2 TCP streams through a MediaTek MT7622 device (2-core Cortex-A53), which runs NAT with flow offload enabled from one ethernet port to PPPoE on another ethernet port + cake qdisc set to 1Gbps. rx-gro-list off: 630 Mbit/s, CPU 35% idle rx-gro-list on: 770 Mbit/s, CPU 40% idle Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-06net: create tcp_gro_header_pull helper functionFelix Fietkau
Pull the code out of tcp_gro_receive in order to access the tcp header from tcp4/6_gro_receive. Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-06net: create tcp_gro_lookup helper functionFelix Fietkau
This pulls the flow port matching out of tcp_gro_receive, so that it can be reused for the next change, which adds the TCP fraglist GRO heuristic. Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-06net: add code for TCP fraglist GROFelix Fietkau
This implements fraglist GRO similar to how it's handled in UDP, however no functional changes are added yet. The next change adds a heuristic for using fraglist GRO instead of regular GRO. Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-05-06net: add support for segmenting TCP fraglist GSO packetsFelix Fietkau
Preparation for adding TCP fraglist GRO support. It expects packets to be combined in a similar way as UDP fraglist GSO packets. For IPv4 packets, NAT is handled in the same way as UDP fraglist GSO. Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Felix Fietkau <nbd@nbd.name> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-04-06net: skbuff: generalize the skb->decrypted bitJakub Kicinski
The ->decrypted bit can be reused for other crypto protocols. Remove the direct dependency on TLS, add helpers to clean up the ifdefs leaking out everywhere. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-03-07net: move tcpv4_offload and tcpv6_offload to net_hotdataEric Dumazet
These are used in TCP fast paths. Move them into net_hotdata for better cache locality. v2: tcpv6_offload definition depends on CONFIG_INET Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20240306160031.874438-8-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-05tcp: gro: micro optimizations in tcp[4]_gro_complete()Eric Dumazet
In tcp_gro_complete() : Moving the skb->inner_transport_header setting allows the compiler to reuse the previously loaded value of skb->transport_header. Caching skb_shinfo() avoids duplications as well. In tcp4_gro_complete(), doing a single change on skb_shinfo(skb)->gso_type also generates better code. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-03-05net: gro: rename skb_gro_header_hard()Eric Dumazet
skb_gro_header_hard() is renamed to skb_gro_may_pull() to match the convention used by common helpers like pskb_may_pull(). This means the condition is inverted: if (skb_gro_header_hard(skb, hlen)) slow_path(); becomes: if (!skb_gro_may_pull(skb, hlen)) slow_path(); Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2023-06-10net: move gso declarations and functions to their own filesEric Dumazet
Move declarations into include/net/gso.h and code into net/core/gso.c Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Stanislav Fomichev <sdf@google.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. Conflicts: net/sched/sch_taprio.c d636fc5dd692 ("net: sched: add rcu annotations around qdisc->qdisc_sleeping") dced11ef84fb ("net/sched: taprio: don't overwrite "sch" variable in taprio_dump_class_stats()") net/ipv4/sysctl_net_ipv4.c e209fee4118f ("net/ipv4: ping_group_range: allow GID from 2147483648 to 4294967294") ccce324dabfe ("tcp: make the first N SYN RTO backoffs linear") https://lore.kernel.org/all/20230605100816.08d41a7b@canb.auug.org.au/ No adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-06tcp: gso: really support BIG TCPEric Dumazet
We missed that tcp_gso_segment() was assuming skb->len was smaller than 65535 : oldlen = (u16)~skb->len; This part came with commit 0718bcc09b35 ("[NET]: Fix CHECKSUM_HW GSO problems.") This leads to wrong TCP checksum. Adapt the code to accept arbitrary packet length. v2: - use two csum_add() instead of csum_fold() (Alexander Duyck) - Change delta type to __wsum to reduce casts (Alexander Duyck) Fixes: 09f3d1a3a52c ("ipv6/gso: remove temporary HBH/jumbo header") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Link: https://lore.kernel.org/r/20230605161647.3624428-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-05-31net: Make gro complete function to return voidParav Pandit
tcp_gro_complete() function only updates the skb fields related to GRO and it always returns zero. All the 3 drivers which are using it do not check for the return value either. Change it to return void instead which simplifies its callers as error handing becomes unnecessary. Signed-off-by: Parav Pandit <parav@nvidia.com> Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-10-03gro: add support of (hw)gro packets to gro stackCoco Li
Current GRO stack only supports incoming packets containing one frame/MSS. This patch changes GRO to accept packets that are already GRO. HW-GRO (aka RSC for some vendors) is very often limited in presence of interleaved packets. Linux SW GRO stack can complete the job and provide larger GRO packets, thus reducing rate of ACK packets and cpu overhead. This also means BIG TCP can still be used, even if HW-GRO/RSC was able to cook ~64 KB GRO packets. v2: fix logic in tcp_gro_receive() Only support TCP for the moment (Paolo) Co-Developed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Coco Li <lixiaoyan@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-25net: gro: skb_gro_header helper functionRichard Gobert
Introduce a simple helper function to replace a common pattern. When accessing the GRO header, we fetch the pointer from frag0, then test its validity and fetch it from the skb when necessary. This leads to the pattern skb_gro_header_fast -> skb_gro_header_hard -> skb_gro_header_slow recurring many times throughout GRO code. This patch replaces these patterns with a single inlined function call, improving code readability. Signed-off-by: Richard Gobert <richardbgobert@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220823071034.GA56142@debian Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2021-11-16net: move gro definitions to include/net/gro.hEric Dumazet
include/linux/netdevice.h became too big, move gro stuff into include/net/gro.h Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-02net, gro: Set inner transport header offset in tcp/udp GRO hookJakub Sitnicki
GSO expects inner transport header offset to be valid when skb->encapsulation flag is set. GSO uses this value to calculate the length of an individual segment of a GSO packet in skb_gso_transport_seglen(). However, tcp/udp gro_complete callbacks don't update the skb->inner_transport_header when processing an encapsulated TCP/UDP segment. As a result a GRO skb has ->inner_transport_header set to a value carried over from earlier skb processing. This can have mild to tragic consequences. From miscalculating the GSO segment length to triggering a page fault [1], when trying to read TCP/UDP header at an address past the skb->data page. The latter scenario leads to an oops report like so: BUG: unable to handle page fault for address: ffff9fa7ec00d008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 123f201067 P4D 123f201067 PUD 123f209067 PMD 0 Oops: 0000 [#1] SMP NOPTI CPU: 44 PID: 0 Comm: swapper/44 Not tainted 5.4.53-cloudflare-2020.7.21 #1 Hardware name: HYVE EDGE-METAL-GEN10/HS-1811DLite1, BIOS V2.15 02/21/2020 RIP: 0010:skb_gso_transport_seglen+0x44/0xa0 Code: c0 41 83 e0 11 f6 87 81 00 00 00 20 74 30 0f b7 87 aa 00 00 00 0f [...] RSP: 0018:ffffad8640bacbb8 EFLAGS: 00010202 RAX: 000000000000feda RBX: ffff9fcc8d31bc00 RCX: ffff9fa7ec00cffc RDX: ffff9fa7ebffdec0 RSI: 000000000000feda RDI: 0000000000000122 RBP: 00000000000005c4 R08: 0000000000000001 R09: 0000000000000000 R10: ffff9fe588ae3800 R11: ffff9fe011fc92f0 R12: ffff9fcc8d31bc00 R13: ffff9fe0119d4300 R14: 00000000000005c4 R15: ffff9fba57d70900 FS: 0000000000000000(0000) GS:ffff9fe68df00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff9fa7ec00d008 CR3: 0000003e99b1c000 CR4: 0000000000340ee0 Call Trace: <IRQ> skb_gso_validate_network_len+0x11/0x70 __ip_finish_output+0x109/0x1c0 ip_sublist_rcv_finish+0x57/0x70 ip_sublist_rcv+0x2aa/0x2d0 ? ip_rcv_finish_core.constprop.0+0x390/0x390 ip_list_rcv+0x12b/0x14f __netif_receive_skb_list_core+0x2a9/0x2d0 netif_receive_skb_list_internal+0x1b5/0x2e0 napi_complete_done+0x93/0x140 veth_poll+0xc0/0x19f [veth] ? mlx5e_napi_poll+0x221/0x610 [mlx5_core] net_rx_action+0x1f8/0x790 __do_softirq+0xe1/0x2bf irq_exit+0x8e/0xc0 do_IRQ+0x58/0xe0 common_interrupt+0xf/0xf </IRQ> The bug can be observed in a simple setup where we send IP/GRE/IP/TCP packets into a netns over a veth pair. Inside the netns, packets are forwarded to dummy device: trafgen -> [veth A]--[veth B] -forward-> [dummy] For veth B to GRO aggregate packets on receive, it needs to have an XDP program attached (for example, a trivial XDP_PASS). Additionally, for UDP, we need to enable GSO_UDP_L4 feature on the device: ip netns exec A ethtool -K AB rx-udp-gro-forwarding on The last component is an artificial delay to increase the chances of GRO batching happening: ip netns exec A tc qdisc add dev AB root \ netem delay 200us slot 5ms 10ms packets 2 bytes 64k With such a setup in place, the bug can be observed by tracing the skb outer and inner offsets when GSO skb is transmitted from the dummy device: tcp: FUNC DEV SKB_LEN NH TH ENC INH ITH GSO_SIZE GSO_TYPE ip_finish_output dumB 2830 270 290 1 294 254 1383 (tcpv4,gre,) ^^^ udp: FUNC DEV SKB_LEN NH TH ENC INH ITH GSO_SIZE GSO_TYPE ip_finish_output dumB 2818 270 290 1 294 254 1383 (gre,udp_l4,) ^^^ Fix it by updating the inner transport header offset in tcp/udp gro_complete callbacks, similar to how {inet,ipv6}_gro_complete callbacks update the inner network header offset, when skb->encapsulation flag is set. [1] https://lore.kernel.org/netdev/CAKxSbF01cLpZem2GFaUaifh0S-5WYViZemTicAg7FCHOnh6kug@mail.gmail.com/ Fixes: bf296b125b21 ("tcp: Add GRO support") Fixes: f993bc25e519 ("net: core: handle encapsulation offloads when computing segment lengths") Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") Reported-by: Alex Forster <aforster@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-15net: use indirect call wrappers at GRO transport layerPaolo Abeni
This avoids an indirect call in the receive path for TCP and UDP packets. TCP takes precedence on UDP, so that we have a single additional conditional in the common case. When IPV6 is build as module, all gro symbols except UDPv6 are builtin, while the latter belong to the ipv6 module, so we need some special care. v1 -> v2: - adapted to INDIRECT_CALL_ changes v2 -> v3: - fix build issue with CONFIG_IPV6=m Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-16tcp: Don't coalesce decrypted and encrypted SKBsBoris Pismenny
Prevent coalescing of decrypted and encrypted SKBs in GRO and TCP layer. Signed-off-by: Boris Pismenny <borisp@mellanox.com> Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-26net: Convert GRO SKB handling to list_head.David Miller
Manage pending per-NAPI GRO packets via list_head. Return an SKB pointer from the GRO receive handlers. When GRO receive handlers return non-NULL, it means that this SKB needs to be completed at this time and removed from the NAPI queue. Several operations are greatly simplified by this transformation, especially timing out the oldest SKB in the list when gro_count exceeds MAX_GRO_SKBS, and napi_gro_flush() which walks the queue in reverse order. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-11tcp: Do not reload skb pointer after skb_gro_receive().David Miller
This is not necessary. skb_gro_receive() will never change what 'head' points to. In it's original implementation (see commit 71d93b39e52e ("net: Add skb_gro_receive")), it did: ==================== + *head = nskb; + nskb->next = p->next; + p->next = NULL; ==================== This sequence was removed in commit 58025e46ea2d ("net: gro: remove obsolete code from skb_gro_receive()") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Eric Dumazet <edumazet@google.com>
2018-01-22gso: validate gso_type in GSO handlersWillem de Bruijn
Validate gso_type during segmentation as SKB_GSO_DODGY sources may pass packets where the gso_type does not match the contents. Syzkaller was able to enter the SCTP gso handler with a packet of gso_type SKB_GSO_TCPV4. On entry of transport layer gso handlers, verify that the gso_type matches the transport protocol. Fixes: 90017accff61 ("sctp: Add GSO support") Link: http://lkml.kernel.org/r/<001a1137452496ffc305617e5fe0@google.com> Reported-by: syzbot+fee64147a25aecd48055@syzkaller.appspotmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-10tcp: gso: avoid refcount_t warning from tcp_gso_segment()Eric Dumazet
When a GSO skb of truesize O is segmented into 2 new skbs of truesize N1 and N2, we want to transfer socket ownership to the new fresh skbs. In order to avoid expensive atomic operations on a cache line subject to cache bouncing, we replace the sequence : refcount_add(N1, &sk->sk_wmem_alloc); refcount_add(N2, &sk->sk_wmem_alloc); // repeated by number of segments refcount_sub(O, &sk->sk_wmem_alloc); by a single refcount_add(sum_of(N) - O, &sk->sk_wmem_alloc); Problem is : In some pathological cases, sum(N) - O might be a negative number, and syzkaller bot was apparently able to trigger this trace [1] atomic_t was ok with this construct, but we need to take care of the negative delta with refcount_t [1] refcount_t: saturated; leaking memory. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 8404 at lib/refcount.c:77 refcount_add_not_zero+0x198/0x200 lib/refcount.c:77 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 8404 Comm: syz-executor2 Not tainted 4.14.0-rc5-mm1+ #20 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 panic+0x1e4/0x41c kernel/panic.c:183 __warn+0x1c4/0x1e0 kernel/panic.c:546 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:177 do_trap_no_signal arch/x86/kernel/traps.c:211 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:260 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:297 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905 RIP: 0010:refcount_add_not_zero+0x198/0x200 lib/refcount.c:77 RSP: 0018:ffff8801c606e3a0 EFLAGS: 00010282 RAX: 0000000000000026 RBX: 0000000000001401 RCX: 0000000000000000 RDX: 0000000000000026 RSI: ffffc900036fc000 RDI: ffffed0038c0dc68 RBP: ffff8801c606e430 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8801d97f5eba R11: 0000000000000000 R12: ffff8801d5acf73c R13: 1ffff10038c0dc75 R14: 00000000ffffffff R15: 00000000fffff72f refcount_add+0x1b/0x60 lib/refcount.c:101 tcp_gso_segment+0x10d0/0x16b0 net/ipv4/tcp_offload.c:155 tcp4_gso_segment+0xd4/0x310 net/ipv4/tcp_offload.c:51 inet_gso_segment+0x60c/0x11c0 net/ipv4/af_inet.c:1271 skb_mac_gso_segment+0x33f/0x660 net/core/dev.c:2749 __skb_gso_segment+0x35f/0x7f0 net/core/dev.c:2821 skb_gso_segment include/linux/netdevice.h:3971 [inline] validate_xmit_skb+0x4ba/0xb20 net/core/dev.c:3074 __dev_queue_xmit+0xe49/0x2070 net/core/dev.c:3497 dev_queue_xmit+0x17/0x20 net/core/dev.c:3538 neigh_hh_output include/net/neighbour.h:471 [inline] neigh_output include/net/neighbour.h:479 [inline] ip_finish_output2+0xece/0x1460 net/ipv4/ip_output.c:229 ip_finish_output+0x85e/0xd10 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:238 [inline] ip_output+0x1cc/0x860 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:459 [inline] ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 ip_queue_xmit+0x8c6/0x18e0 net/ipv4/ip_output.c:504 tcp_transmit_skb+0x1ab7/0x3840 net/ipv4/tcp_output.c:1137 tcp_write_xmit+0x663/0x4de0 net/ipv4/tcp_output.c:2341 __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2513 tcp_push_pending_frames include/net/tcp.h:1722 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5050 [inline] tcp_rcv_established+0x8c7/0x18a0 net/ipv4/tcp_input.c:5497 tcp_v4_do_rcv+0x2ab/0x7d0 net/ipv4/tcp_ipv4.c:1460 sk_backlog_rcv include/net/sock.h:909 [inline] __release_sock+0x124/0x360 net/core/sock.c:2264 release_sock+0xa4/0x2a0 net/core/sock.c:2776 tcp_sendmsg+0x3a/0x50 net/ipv4/tcp.c:1462 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 sock_sendmsg_nosec net/socket.c:632 [inline] sock_sendmsg+0xca/0x110 net/socket.c:642 ___sys_sendmsg+0x31c/0x890 net/socket.c:2048 __sys_sendmmsg+0x1e6/0x5f0 net/socket.c:2138 Fixes: 14afee4b6092 ("net: convert sock.sk_wmem_alloc from atomic_t to refcount_t") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01net: convert sock.sk_wmem_alloc from atomic_t to refcount_tReshetova, Elena
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-19gso: Support partial splitting at the frag_list pointerSteffen Klassert
Since commit 8a29111c7 ("net: gro: allow to build full sized skb") gro may build buffers with a frag_list. This can hurt forwarding because most NICs can't offload such packets, they need to be segmented in software. This patch splits buffers with a frag_list at the frag_list pointer into buffers that can be TSO offloaded. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Alexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-20gso: Remove arbitrary checks for unsupported GSOTom Herbert
In several gso_segment functions there are checks of gso_type against a seemingly arbitrary list of SKB_GSO_* flags. This seems like an attempt to identify unsupported GSO types, but since the stack is the one that set these GSO types in the first place this seems unnecessary to do. If a combination isn't valid in the first place that stack should not allow setting it. This is a code simplication especially for add new GSO types. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-14GSO: Support partial segmentation offloadAlexander Duyck
This patch adds support for something I am referring to as GSO partial. The basic idea is that we can support a broader range of devices for segmentation if we use fixed outer headers and have the hardware only really deal with segmenting the inner header. The idea behind the naming is due to the fact that everything before csum_start will be fixed headers, and everything after will be the region that is handled by hardware. With the current implementation it allows us to add support for the following GSO types with an inner TSO_MANGLEID or TSO6 offload: NETIF_F_GSO_GRE NETIF_F_GSO_GRE_CSUM NETIF_F_GSO_IPIP NETIF_F_GSO_SIT NETIF_F_UDP_TUNNEL NETIF_F_UDP_TUNNEL_CSUM In the case of hardware that already supports tunneling we may be able to extend this further to support TSO_TCPV4 without TSO_MANGLEID if the hardware can support updating inner IPv4 headers. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-14GRO: Add support for TCP with fixed IPv4 ID field, limit tunnel IP ID valuesAlexander Duyck
This patch does two things. First it allows TCP to aggregate TCP frames with a fixed IPv4 ID field. As a result we should now be able to aggregate flows that were converted from IPv6 to IPv4. In addition this allows us more flexibility for future implementations of segmentation as we may be able to use a fixed IP ID when segmenting the flow. The second thing this does is that it places limitations on the outer IPv4 ID header in the case of tunneled frames. Specifically it forces the IP ID to be incrementing by 1 unless the DF bit is set in the outer IPv4 header. This way we can avoid creating overlapping series of IP IDs that could possibly be fragmented if the frame goes through GRO and is then resegmented via GSO. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-14GSO: Add GSO type for fixed IPv4 IDAlexander Duyck
This patch adds support for TSO using IPv4 headers with a fixed IP ID field. This is meant to allow us to do a lossless GRO in the case of TCP flows that use a fixed IP ID such as those that convert IPv6 header to IPv4 headers. In addition I am adding a feature that for now I am referring to TSO with IP ID mangling. Basically when this flag is enabled the device has the option to either output the flow with incrementing IP IDs or with a fixed IP ID regardless of what the original IP ID ordering was. This is useful in cases where the DF bit is set and we do not care if the original IP ID value is maintained. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-11net: Store checksum result for offloaded GSO checksumsAlexander Duyck
This patch makes it so that we can offload the checksums for a packet up to a certain point and then begin computing the checksums via software. Setting this up is fairly straight forward as all we need to do is reset the values stored in csum and csum_start for the GSO context block. One complication for this is remote checksum offload. In order to allow the inner checksums to be offloaded while computing the outer checksum manually we needed to have some way of indicating that the offload wasn't real. In order to do that I replaced CHECKSUM_PARTIAL with CHECKSUM_UNNECESSARY in the case of us computing checksums for the outer header while skipping computing checksums for the inner headers. We clean up the ip_summed flag and set it to either CHECKSUM_PARTIAL or CHECKSUM_NONE once we hand the packet off to the next lower level. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-11tcp: reserve tcp_skb_mss() to tcp stackEric Dumazet
tcp_gso_segment() and tcp_gro_receive() are not strictly part of TCP stack. They should not assume tcp_skb_mss(skb) is in fact skb_shinfo(skb)->gso_size. This will allow us to change tcp_skb_mss() in following patches. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-02-28tcp: cleanup static functionsEric Dumazet
tcp_fastopen_create_child() is static and should not be exported. tcp4_gso_segment() and tcp6_gso_segment() should be static. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-05net: Remove MPLS GSO feature.Pravin B Shelar
Device can export MPLS GSO support in dev->mpls_features same way it export vlan features in dev->vlan_features. So it is safe to remove NETIF_F_GSO_MPLS redundant flag. Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
2014-11-05udp: Changes to udp_offload to support remote checksum offloadTom Herbert
Add a new GSO type, SKB_GSO_TUNNEL_REMCSUM, which indicates remote checksum offload being done (in this case inner checksum must not be offloaded to the NIC). Added logic in __skb_udp_tunnel_segment to handle remote checksum offload case. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-26net: Remove gso_send_check as an offload callbackTom Herbert
The send_check logic was only interesting in cases of TCP offload and UDP UFO where the checksum needed to be initialized to the pseudo header checksum. Now we've moved that logic into the related gso_segment functions so gso_send_check is no longer needed. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-26tcp: move logic out of tcp_v[64]_gso_send_checkTom Herbert
In tcp_v[46]_gso_send_check the TCP checksum is initialized to the pseudo header checksum using __tcp_v[46]_send_check. We can move this logic into new tcp[46]_gso_segment functions to be done when ip_summed != CHECKSUM_PARTIAL (ip_summed == CHECKSUM_PARTIAL should be the common case, possibly always true when taking GSO path). After this change tcp_v[46]_gso_send_check is no-op. Signed-off-by: Tom Herbert <therbert@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-24tcp: Call skb_gro_checksum_validateTom Herbert
In tcp[64]_gro_receive call skb_gro_checksum_validate to validate TCP checksum in the gro context. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-06net-timestamp: cumulative tcp timestamping fixesWillem de Bruijn
A set of small fixes pointed out just after the merge: - make tcp_tx_timestamp static - make tcp_gso_tstamp static - use before() to compare TCP seqno, instead of cast to u64 - add tstamp to tx_flags in GSO, instead of overwrite tx_flags - record skb_shinfo(skb)->tskey for all timestamps, also HW. - optimization in tcp_tx_timestamp: call sock_tx_timestamp only if a tstamp option is set. Signed-off-by: Willem de Bruijn <willemb@google.com> Fixes: 4ed2d765dfac ("net-timestamp: TCP timestamping") Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05net-timestamp: TCP timestampingWillem de Bruijn
TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
generated by cgit (git 2.34.1) at 2025-07-25 19:31:22 +0000