kernel.git/include/linux/tcp.h, branch linux-6.14.y

tcp: be less liberal in TSEcr received while in SYN_RECV state

2025-05-29T09:13:05Z

[ Upstream commit 3ba075278c11cdb19e2dbb80362042f1b0c08f74 ] Yong-Hao Zou mentioned that linux was not strict as other OS in 3WHS, for flows using TCP TS option (RFC 7323) As hinted by an old comment in tcp_check_req(), we can check the TSEcr value in the incoming packet corresponds to one of the SYNACK TSval values we have sent. In this patch, I record the oldest and most recent values that SYNACK packets have used. Send a challenge ACK if we receive a TSEcr outside of this range, and increase a new SNMP counter. nstat -az | grep TSEcrRejected TcpExtTSEcrRejected 0 0.0 Due to TCP fastopen implementation, do not apply yet these checks for fastopen flows. v2: No longer use req->num_timeout, but treq->snt_tsval_first to detect when first SYNACK is prepared. This means we make sure to not send an initial zero TSval. Make sure MPTCP and TCP selftests are passing. Change MIB name to TcpExtTSEcrRejected v1: https://lore.kernel.org/netdev/CADVnQykD8i4ArpSZaPKaoNxLJ2if2ts9m4As+=Jvdkrgx1qMHw@mail.gmail.com/T/ Reported-by: Yong-Hao Zou Signed-off-by: Eric Dumazet Reviewed-by: Matthieu Baerts (NGI0) Reviewed-by: Neal Cardwell Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250225171048.3105061-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: tcp: replace the document for "lsndtime" in tcp_sock

2024-11-05T02:10:56Z

Commit d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") moved the fields around and misplaced the documentation for "lsndtime". So, let's replace it in the proper place. Signed-off-by: Menglong Dong Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241104070041.64302-1-dongml2@chinatelecom.cn Signed-off-by: Jakub Kicinski

tcp: more struct tcp_sock adjustments

2024-04-08T10:49:02Z

tp->recvmsg_inq is used from tcp recvmsg() thus should be in tcp_sock_read_rx group. tp->tcp_clock_cache and tp->tcp_mstamp are written both in rx and tx paths, thus are better placed in tcp_sock_write_txrx group. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp: align tcp_sock_write_rx group

2024-03-05T04:46:18Z

Stephen Rothwell and kernel test robot reported that some arches (parisc, hexagon) and/or compilers would not like blamed commit. Lets make sure tcp_sock_write_rx group does not start with a hole. While we are at it, correct tcp_sock_write_tx CACHELINE_ASSERT_GROUP_SIZE() since after the blamed commit, we went to 105 bytes. Fixes: 99123622050f ("tcp: remove some holes in struct tcp_sock") Reported-by: Stephen Rothwell Reported-by: kernel test robot Link: https://lore.kernel.org/netdev/20240301121108.5d39e4f9@canb.auug.org.au/ Closes: https://lore.kernel.org/oe-kbuild-all/202403011451.csPYOS3C-lkp@intel.com/ Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Tested-by: Simon Horman # build-tested Link: https://lore.kernel.org/r/20240301171945.2958176-1-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: remove some holes in struct tcp_sock

2024-02-29T04:21:24Z

By moving some fields around, this patch shrinks holes size from 56 to 32, saving 24 bytes on 64bit arches. After the patch pahole gives the following for 'struct tcp_sock': /* size: 2304, cachelines: 36, members: 162 */ /* sum members: 2234, holes: 6, sum holes: 32 */ /* sum bitfield members: 34 bits, bit holes: 5, sum bit holes: 14 bits */ /* padding: 32 */ /* paddings: 3, sum paddings: 10 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 12 */ Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240227192721.3558982-1-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: move tp->tcp_usec_ts to tcp_sock_read_txrx group

2024-02-12T09:51:26Z

tp->tcp_usec_ts is a read mostly field, used in rx and tx fast paths. Fixes: d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") Signed-off-by: Eric Dumazet Cc: Coco Li Cc: Wei Wang Reviewed-by: Simon Horman Signed-off-by: David S. Miller

tcp: move tp->scaling_ratio to tcp_sock_read_txrx group

2024-02-12T09:51:26Z

tp->scaling_ratio is a read mostly field, used in rx and tx fast paths. Fixes: d5fed5addb2b ("tcp: reorganize tcp_sock fast path variables") Signed-off-by: Eric Dumazet Cc: Coco Li Cc: Wei Wang Reviewed-by: Simon Horman Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2023-12-08T01:53:17Z

Cross-merge networking fixes after downstream PR. Conflicts: drivers/net/ethernet/stmicro/stmmac/dwmac5.c drivers/net/ethernet/stmicro/stmmac/dwmac5.h drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c drivers/net/ethernet/stmicro/stmmac/hwif.h 37e4b8df27bc ("net: stmmac: fix FPE events losing") c3f3b97238f6 ("net: stmmac: Refactor EST implementation") https://lore.kernel.org/all/20231206110306.01e91114@canb.auug.org.au/ Adjacent changes: net/ipv4/tcp_ao.c 9396c4ee93f9 ("net/tcp: Don't store TCP-AO maclen on reqsk") 7b0f570f879a ("tcp: Move TCP-AO bits from cookie_v[46]_check() to tcp_ao_syncookie().") Signed-off-by: Jakub Kicinski

net/tcp: Don't store TCP-AO maclen on reqsk

2023-12-06T11:36:56Z

This extra check doesn't work for a handshake when SYN segment has (current_key.maclen != rnext_key.maclen). It could be amended to preserve rnext_key.maclen instead of current_key.maclen, but that requires a lookup on listen socket. Originally, this extra maclen check was introduced just because it was cheap. Drop it and convert tcp_request_sock::maclen into boolean tcp_request_sock::used_tcp_ao. Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Signed-off-by: Dmitry Safonov Reviewed-by: Eric Dumazet Signed-off-by: Paolo Abeni

tcp: reorganize tcp_sock fast path variables

2023-12-06T04:16:05Z

The variables are organized according in the following way: - TX read-mostly hotpath cache lines - TXRX read-mostly hotpath cache lines - RX read-mostly hotpath cache lines - TX read-write hotpath cache line - TXRX read-write hotpath cache line - RX read-write hotpath cache line Fastpath cachelines end after rcvq_space. Cache line boundaries are enforced only between read-mostly and read-write. That is, if read-mostly tx cachelines bleed into read-mostly txrx cachelines, we do not care. We care about the boundaries between read and write cachelines because we want to prevent false sharing. Fast path variables span cache lines before change: 12 Fast path variables span cache lines after change: 8 Suggested-by: Eric Dumazet Reviewed-by: Wei Wang Signed-off-by: Coco Li Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20231204201232.520025-3-lixiaoyan@google.com Signed-off-by: Jakub Kicinski