kernel/linux.git/include/net/netns/ipv6.h, branch v6.19.12

ipv6: icmp: Add RFC 5837 support

2025-10-30T01:28:30+00:00

Add the ability to append the incoming IP interface information to ICMPv6 error messages in accordance with RFC 5837 and RFC 4884. This is required for more meaningful traceroute results in unnumbered networks. The feature is disabled by default and controlled via a new sysctl ("net.ipv6.icmp.errors_extension_mask") which accepts a bitmask of ICMP extensions to append to ICMP error messages. Currently, only a single value is supported, but the interface and the implementation should be able to support more extensions, if needed. Clone the skb and copy the relevant data portions before modifying the skb as the caller of icmp6_send() still owns the skb after the function returns. This should be fine since by default ICMP error messages are rate limited to 1000 per second and no more than 1 per second per specific host. Trim or pad the packet to 128 bytes before appending the ICMP extension structure in order to be compatible with legacy applications that assume that the ICMP extension structure always starts at this offset (the minimum length specified by RFC 4884). Since commit 20e1954fe238 ("ipv6: RFC 4884 partial support for SIT/GRE tunnels") it is possible for icmp6_send() to be called with an skb that already contains ICMP extensions. This can happen when we receive an ICMPv4 message with extensions from a tunnel and translate it to an ICMPv6 message towards an IPv6 host in the overlay network. I could not find an RFC that supports this behavior, but it makes sense to not overwrite the original extensions that were appended to the packet. Therefore, avoid appending extensions if the length field in the provided ICMPv6 header is already filled. Export netdev_copy_name() using EXPORT_IPV6_MOD_GPL() to make it available to IPv6 when it is built as a module. Reviewed-by: Petr Machata Reviewed-by: David Ahern Reviewed-by: Willem de Bruijn Signed-off-by: Ido Schimmel Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251027082232.232571-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski

ipv6: Protect fib6_link_table() with spinlock.

2025-04-24T07:29:56+00:00

We will get rid of RTNL from RTM_NEWROUTE and SIOCADDRT. If the request specifies a new table ID, fib6_new_table() is called to create a new routing table. Two concurrent requests could specify the same table ID, so we need a lock to protect net->ipv6.fib_table_hash[h]. Let's add a spinlock to protect the hash bucket linkage. Signed-off-by: Kuniyuki Iwashima Acked-by: Paolo Abeni Link: https://patch.msgid.link/20250418000443.43734-13-kuniyu@amazon.com Signed-off-by: Paolo Abeni

net/ipv6: convert skip_notify_on_dev_down sysctl to u8

2023-06-03T05:55:43+00:00

Save a bit a space, and could help future sysctls to use the same pattern. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Acked-by: Matthieu Baerts Signed-off-by: Jakub Kicinski

net/ipv6: fix bool/int mismatch for skip_notify_on_dev_down

2023-06-03T05:55:43+00:00

skip_notify_on_dev_down ctl table expects this field to be an int (4 bytes), not a bool (1 byte). Because proc_dou8vec_minmax() was added in 5.13, this patch converts skip_notify_on_dev_down to an int. Following patch then converts the field to u8 and use proc_dou8vec_minmax(). Fixes: 7c6bb7d2faaf ("net/ipv6: Add knob to skip DELROUTE message on device down") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Acked-by: Matthieu Baerts Signed-off-by: Jakub Kicinski

ipv6: add icmpv6_error_anycast_as_unicast for ICMPv6

2023-04-21T03:07:50+00:00

ICMPv6 error packets are not sent to the anycast destinations and this prevents things like traceroute from working. So create a setting similar to ECHO when dealing with Anycast sources (icmpv6_echo_ignore_anycast). Signed-off-by: Mahesh Bandewar Reviewed-by: David Ahern Reviewed-by: Maciej Żenczykowski Link: https://lore.kernel.org/r/20230419013238.2691167-1-maheshb@google.com Signed-off-by: Jakub Kicinski

ipv6: make ip6_rt_gc_expire an atomic_t

2022-04-15T21:28:50+00:00

Reads and Writes to ip6_rt_gc_expire always have been racy, as syzbot reported lately [1] There is a possible risk of under-flow, leading to unexpected high value passed to fib6_run_gc(), although I have not observed this in the field. Hosts hitting ip6_dst_gc() very hard are under pretty bad state anyway. [1] BUG: KCSAN: data-race in ip6_dst_gc / ip6_dst_gc read-write to 0xffff888102110744 of 4 bytes by task 13165 on cpu 1: ip6_dst_gc+0x1f3/0x220 net/ipv6/route.c:3311 dst_alloc+0x9b/0x160 net/core/dst.c:86 ip6_dst_alloc net/ipv6/route.c:344 [inline] icmp6_dst_alloc+0xb2/0x360 net/ipv6/route.c:3261 mld_sendpack+0x2b9/0x580 net/ipv6/mcast.c:1807 mld_send_cr net/ipv6/mcast.c:2119 [inline] mld_ifc_work+0x576/0x800 net/ipv6/mcast.c:2651 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289 worker_thread+0x618/0xa70 kernel/workqueue.c:2436 kthread+0x1a9/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 read-write to 0xffff888102110744 of 4 bytes by task 11607 on cpu 0: ip6_dst_gc+0x1f3/0x220 net/ipv6/route.c:3311 dst_alloc+0x9b/0x160 net/core/dst.c:86 ip6_dst_alloc net/ipv6/route.c:344 [inline] icmp6_dst_alloc+0xb2/0x360 net/ipv6/route.c:3261 mld_sendpack+0x2b9/0x580 net/ipv6/mcast.c:1807 mld_send_cr net/ipv6/mcast.c:2119 [inline] mld_ifc_work+0x576/0x800 net/ipv6/mcast.c:2651 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289 worker_thread+0x618/0xa70 kernel/workqueue.c:2436 kthread+0x1a9/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 value changed: 0x00000bb3 -> 0x00000ba9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 11607 Comm: kworker/0:21 Not tainted 5.18.0-rc1-syzkaller-00037-g42e7a03d3bad-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: mld mld_ifc_work Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20220413181333.649424-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski

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

2022-02-17T19:44:20+00:00

No conflicts. Signed-off-by: Jakub Kicinski

ipv6: per-netns exclusive flowlabel checks

2022-02-17T04:37:47+00:00

Ipv6 flowlabels historically require a reservation before use. Optionally in exclusive mode (e.g., user-private). Commit 59c820b2317f ("ipv6: elide flowlabel check if no exclusive leases exist") introduced a fastpath that avoids this check when no exclusive leases exist in the system, and thus any flowlabel use will be granted. That allows skipping the control operation to reserve a flowlabel entirely. Though with a warning if the fast path fails: This is an optimization. Robust applications still have to revert to requesting leases if the fast path fails due to an exclusive lease. Still, this is subtle. Better isolate network namespaces from each other. Flowlabels are per-netns. Also record per-netns whether exclusive leases are in use. Then behavior does not change based on activity in other netns. Changes v2 - wrap in IS_ENABLED(CONFIG_IPV6) to avoid breakage if disabled Fixes: 59c820b2317f ("ipv6: elide flowlabel check if no exclusive leases exist") Link: https://lore.kernel.org/netdev/MWHPR2201MB1072BCCCFCE779E4094837ACD0329@MWHPR2201MB1072.namprd22.prod.outlook.com/ Reported-by: Congyu Liu Signed-off-by: Willem de Bruijn Tested-by: Congyu Liu Link: https://lore.kernel.org/r/20220215160037.1976072-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski

ipv6/addrconf: use one delayed work per netns

2022-02-09T04:41:32+00:00

Next step for using per netns inet6_addr_lst is to have per netns work item to ultimately call addrconf_verify_rtnl() and addrconf_verify() with a new 'struct net*' argument. Everything is still using the global inet6_addr_lst[] table. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski

ipv6/addrconf: allocate a per netns hash table

2022-02-09T04:41:32+00:00

Add a per netns hash table and a dedicated spinlock, first step to get rid of the global inet6_addr_lst[] one. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: Jakub Kicinski