kernel/linux.git/Documentation/networking, branch v6.18.21

ipv6: Move ipv6_fl_list from ipv6_pinfo to inet_sock.

2026-03-04T12:20:44+00:00

[ Upstream commit 1c17f4373d4db1e1f0ebd3ddcd8e7a642927a826 ] In {tcp6,udp6,raw6}_sock, struct ipv6_pinfo is always placed at the beginning of a new cache line because 1. __alignof__(struct tcp_sock) is 64 due to ____cacheline_aligned of __cacheline_group_begin(tcp_sock_write_tx) 2. __alignof__(struct udp_sock) is 64 due to ____cacheline_aligned of struct numa_drop_counters 3. in raw6_sock, struct numa_drop_counters is placed before struct ipv6_pinfo . struct ipv6_pinfo is 136 bytes, but the last cache line is only used by ipv6_fl_list: $ pahole -C ipv6_pinfo vmlinux struct ipv6_pinfo { ... /* --- cacheline 2 boundary (128 bytes) --- */ struct ipv6_fl_socklist * ipv6_fl_list; /* 128 8 */ /* size: 136, cachelines: 3, members: 23 */ Let's move ipv6_fl_list from struct ipv6_pinfo to struct inet_sock to save a full cache line for {tcp6,udp6,raw6}_sock. Now, struct ipv6_pinfo is 128 bytes, and {tcp6,udp6,raw6}_sock have 64 bytes less, while {tcp,udp,raw}_sock retain the same size. Before: # grep -E "^(RAW|UDP[^L\-]|TCP)" /proc/slabinfo | awk '{print $1, "\t", $4}' RAWv6 1408 UDPv6 1472 TCPv6 2560 RAW 1152 UDP 1280 TCP 2368 After: # grep -E "^(RAW|UDP[^L\-]|TCP)" /proc/slabinfo | awk '{print $1, "\t", $4}' RAWv6 1344 UDPv6 1408 TCPv6 2496 RAW 1152 UDP 1280 TCP 2368 Also, ipv6_fl_list and inet_flags (SNDFLOW bit) are placed in the same cache line. $ pahole -C inet_sock vmlinux ... /* --- cacheline 11 boundary (704 bytes) was 56 bytes ago --- */ struct ipv6_pinfo * pinet6; /* 760 8 */ /* --- cacheline 12 boundary (768 bytes) --- */ struct ipv6_fl_socklist * ipv6_fl_list; /* 768 8 */ unsigned long inet_flags; /* 776 8 */ Doc churn is due to the insufficient Type column (only 1 space short). Suggested-by: Eric Dumazet Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20251014224210.2964778-1-kuniyu@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 858d2a4f67ff ("tcp: fix potential race in tcp_v6_syn_recv_sock()") Signed-off-by: Sasha Levin

ipv6: icmp: remove obsolete code in icmpv6_xrlim_allow()

2026-02-26T22:59:40+00:00

[ Upstream commit 0201eedb69b24a6be9b7c1716287a89c4dde2320 ] Following part was needed before the blamed commit, because inet_getpeer_v6() second argument was the prefix. /* Give more bandwidth to wider prefixes. */ if (rt->rt6i_dst.plen < 128) tmo >>= ((128 - rt->rt6i_dst.plen)>>5); Now inet_getpeer_v6() retrieves hosts, we need to remove @tmo adjustement or wider prefixes likes /24 allow 8x more ICMP to be sent for a given ratelimit. As we had this issue for a while, this patch changes net.ipv6.icmp.ratelimit default value from 1000ms to 100ms to avoid potential regressions. Also add a READ_ONCE() when reading net->ipv6.sysctl.icmpv6_time. Fixes: fd0273d7939f ("ipv6: Remove external dependency on rt6i_dst and rt6i_src") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Cc: Martin KaFai Lau Link: https://patch.msgid.link/20260216142832.3834174-4-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

Documentation: netconsole: Remove obsolete contact people

2025-10-30T00:40:19+00:00

Breno Leitao has been listed in MAINTAINERS as netconsole maintainer since 7c938e438c56db ("MAINTAINERS: make Breno the netconsole maintainer"), but the documentation says otherwise that bug reports should be sent to original netconsole authors. Remove obsolate contact info. Signed-off-by: Bagas Sanjaya Reviewed-by: Randy Dunlap Tested-by: Randy Dunlap Link: https://patch.msgid.link/20251028132027.48102-1-bagasdotme@gmail.com Signed-off-by: Jakub Kicinski

Documentation: networking: ax25: update the mailing list info.

2025-10-22T00:41:57+00:00

Update the mailing list subscription information for the linux-hams mailing list. Signed-off-by: Randy Dunlap Reviewed-by: Simon Horman Link: https://patch.msgid.link/20251020052716.3136773-1-rdunlap@infradead.org Signed-off-by: Jakub Kicinski

Documentation: net: net_failover: Separate cloud-ifupdown-helper and reattach-vf.sh code blocks marker

2025-10-17T23:28:29+00:00

cloud-ifupdown-helper patch and reattach-vf.sh script are rendered in htmldocs output as normal paragraphs instead of literal code blocks due to missing separator from respective code block marker. Add it. Signed-off-by: Bagas Sanjaya Reviewed-by: Simon Horman Link: https://patch.msgid.link/20251016093936.29442-2-bagasdotme@gmail.com Signed-off-by: Jakub Kicinski

net: rmnet: Fix checksum offload header v5 and aggregation packet formatting

2025-10-16T22:50:52+00:00

Packet format for checksum offload header v5 and aggregation, and header type table for the former, are shown in normal paragraphs instead. Use appropriate markup. Signed-off-by: Bagas Sanjaya Reviewed-by: Simon Horman Link: https://patch.msgid.link/20251015092540.32282-2-bagasdotme@gmail.com Signed-off-by: Jakub Kicinski

Merge tag 'linux-can-fixes-for-6.18-20251014' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

2025-10-16T00:56:20+00:00

Marc Kleine-Budde says: ==================== pull-request: can 2025-10-14 The first 2 paches are by Celeste Liu and target the gS_usb driver. The first patch remove the limitation to 3 CAN interface per USB device. The second patch adds the missing population of net_device->dev_port. The next 4 patches are by me and fix the m_can driver. They add a missing pm_runtime_disable(), fix the CAN state transition back to Error Active and fix the state after ifup and suspend/resume. Another patch by me targets the m_can driver, too and replaces Dong Aisheng's old email address. The next 2 patches are by Vincent Mailhol and update the CAN networking Documentation. Tetsuo Handa contributes the last patch that add missing cleanup calls in the NETDEV_UNREGISTER notification handler. * tag 'linux-can-fixes-for-6.18-20251014' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can: can: j1939: add missing calls in NETDEV_UNREGISTER notification handler can: add Transmitter Delay Compensation (TDC) documentation can: remove false statement about 1:1 mapping between DLC and length can: m_can: replace Dong Aisheng's old email address can: m_can: fix CAN state in system PM can: m_can: m_can_chip_config(): bring up interface in correct state can: m_can: m_can_handle_state_errors(): fix CAN state transition to Error Active can: m_can: m_can_plat_remove(): add missing pm_runtime_disable() can: gs_usb: gs_make_candev(): populate net_device->dev_port can: gs_usb: increase max interface to U8_MAX ==================== Link: https://patch.msgid.link/20251014122140.990472-1-mkl@pengutronix.de Signed-off-by: Jakub Kicinski

can: add Transmitter Delay Compensation (TDC) documentation

2025-10-13T19:26:01+00:00

Back in 2021, support for CAN TDC was added to the kernel in series [1] and in iproute2 in series [2]. However, the documentation was never updated. Add a new sub-section under CAN-FD driver support to document how to configure the TDC using the "ip tool". [1] add the netlink interface for CAN-FD Transmitter Delay Compensation (TDC) Link: https://lore.kernel.org/all/20210918095637.20108-1-mailhol.vincent@wanadoo.fr/ [2] iplink_can: cleaning, fixes and adding TDC support Link: https://lore.kernel.org/all/20211103164428.692722-1-mailhol.vincent@wanadoo.fr/ Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20251013-can-fd-doc-v2-2-5d53bdc8f2ad@kernel.org Signed-off-by: Marc Kleine-Budde

can: remove false statement about 1:1 mapping between DLC and length

2025-10-13T19:26:01+00:00

The CAN-FD section of can.rst still states that there is a 1:1 mapping between the Classical CAN DLC and its length. This is only true for the DLC values up to 8. Beyond that point, the length remains at 8. For reference, the mapping between the CAN DLC and the length is given in below table [1]: DLC value CBFF and CEFF FBFF and FEFF [decimal] [byte] [byte] ---------------------------------------------- 0 0 0 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 9 8 12 10 8 16 11 8 20 12 8 24 13 8 32 14 8 48 15 8 64 Remove the erroneous statement. Instead just state that the length of a Classical CAN frame ranges from 0 to 8. [1] ISO 11898-1:2024, Table 5 -- DLC: coding of the four LSB Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20251013-can-fd-doc-v2-1-5d53bdc8f2ad@kernel.org Signed-off-by: Marc Kleine-Budde

doc: fix seg6_flowlabel path

2025-10-12T21:51:37+00:00

This sysctl is not per interface; it's global per netns. Fixes: 292ecd9f5a94 ("doc: move seg6_flowlabel to seg6-sysctl.rst") Reported-by: Philippe Guibert Signed-off-by: Nicolas Dichtel Reviewed-by: Simon Horman Signed-off-by: David S. Miller