kernel/linux.git/include/linux/ipv6.h, branch v7.0-rc7

ipv6: move the disable_ipv6_mod knob to core code

2026-03-12T00:53:37+00:00

From: Jakub Kicinski Make sure disable_ipv6_mod itself is not part of the IPv6 module, in case core code wants to refer to it. We will remove support for IPv6=m soon, this change helps make fixes we commit before that less messy. Link: https://patch.msgid.link/20260307-net-nd_tbl_fixes-v4-1-e2677e85628c@suse.com Signed-off-by: Jakub Kicinski

ipv6: add daddr/final storage in struct ipv6_pinfo

2026-02-11T04:57:49+00:00

After commit b409a7f7176b ("ipv6: colocate inet6_cork in inet_cork_full") we have room in ipv6_pinfo to hold daddr/final in case they need to be populated in fl6_update_dst() calls. This will allow stack canary removal in IPv6 tx fast paths. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260206173426.1638518-2-edumazet@google.com Signed-off-by: Jakub Kicinski

net/ipv6: Drop HBH for BIG TCP on TX side

2026-02-07T04:50:12+00:00

BIG TCP IPv6 inserts a hop-by-hop extension header to indicate the real IPv6 payload length when it doesn't fit into the 16-bit field in the IPv6 header itself. While it helps tools parse the packet, it also requires every driver that supports TSO and BIG TCP to remove this 8-byte extension header. It might not sound that bad until we try to apply it to tunneled traffic. Currently, the drivers don't attempt to strip HBH if skb->encapsulation = 1. Moreover, trying to do so would require dissecting different tunnel protocols and making corresponding adjustments on case-by-case basis, which would slow down the fastpath (potentially also requiring adjusting checksums in outer headers). At the same time, BIG TCP IPv4 doesn't insert any extra headers and just calculates the payload length from skb->len, significantly simplifying implementing BIG TCP for tunnels. Stop inserting HBH when building BIG TCP GSO SKBs. Signed-off-by: Alice Mikityanska Acked-by: Paolo Abeni Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260205133925.526371-3-alice.kernel@fastmail.im Signed-off-by: Jakub Kicinski

net/ipv6: Introduce payload_len helpers

2026-02-07T04:50:03+00:00

The next commits will transition away from using the hop-by-hop extension header to encode packet length for BIG TCP. Add wrappers around ip6->payload_len that return the actual value if it's non-zero, and calculate it from skb->len if payload_len is set to zero (and a symmetrical setter). The new helpers are used wherever the surrounding code supports the hop-by-hop jumbo header for BIG TCP IPv6, or the corresponding IPv4 code uses skb_ip_totlen (e.g., in include/net/netfilter/nf_tables_ipv6.h). No behavioral change in this commit. Signed-off-by: Alice Mikityanska Acked-by: Paolo Abeni Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260205133925.526371-2-alice.kernel@fastmail.im Signed-off-by: Jakub Kicinski

ipv6: colocate inet6_cork in inet_cork_full

2026-02-03T01:49:30+00:00

All inet6_cork users also use one inet_cork_full. Reduce number of parameters and increase data locality. This saves ~275 bytes of code on x86_64. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260130210303.3888261-9-edumazet@google.com Signed-off-by: Jakub Kicinski

ipv6: Move ipv6_fl_list from ipv6_pinfo to inet_sock.

2025-10-17T23:06:52+00:00

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

ipv6: reorganise struct ipv6_pinfo

2025-09-18T08:17:09+00:00

Move fields used in tx fast path at the beginning of the structure, and seldom used ones at the end. Note that rxopt is also in the first cache line. Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250916160951.541279-5-edumazet@google.com Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni

ipv6: make ipv6_pinfo.daddr_cache a boolean

2025-09-18T08:17:09+00:00

ipv6_pinfo.daddr_cache is either NULL or &sk->sk_v6_daddr We do not need 8 bytes, a boolean is enough. Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250916160951.541279-3-edumazet@google.com Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni

ipv6: make ipv6_pinfo.saddr_cache a boolean

2025-09-18T08:17:09+00:00

ipv6_pinfo.saddr_cache is either NULL or &np->saddr. We do not need 8 bytes, a boolean is enough. Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250916160951.541279-2-edumazet@google.com Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni

net: use NUMA drop counters for softnet_data.dropped

2025-09-14T18:35:17+00:00

Hosts under DOS attack can suffer from false sharing in enqueue_to_backlog() : atomic_inc(&sd->dropped). This is because sd->dropped can be touched from many cpus, possibly residing on different NUMA nodes. Generalize the sk_drop_counters infrastucture added in commit c51613fa276f ("net: add sk->sk_drop_counters") and use it to replace softnet_data.dropped with NUMA friendly softnet_data.drop_counters. This adds 64 bytes per cpu, maybe more in the future if we increase the number of counters (currently 2) per 'struct numa_drop_counters'. Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250909121942.1202585-1-edumazet@google.com Signed-off-by: Jakub Kicinski