Steffen Klassert says:
====================
pull request (net): ipsec 2026-01-14
1) Fix inner mode lookup in tunnel mode GSO segmentation.
The protocol was taken from the wrong field.
2) Set ipv4 no_pmtu_disc flag only on output SAs. The
insertation of input SAs can fail if no_pmtu_disc
is set.
Please pull or let me know if there are problems.
ipsec-2026-01-14
* tag 'ipsec-2026-01-14' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: set ipv4 no_pmtu_disc flag only on output sa when direction is set
xfrm: Fix inner mode lookup in tunnel mode GSO segmentation
====================
Link: https://patch.msgid.link/20260114121817.1106134-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Analog to commit db5b4e39c4 ("ip6_gre: make ip6gre_header() robust")
Over the years, syzbot found many ways to crash the kernel
in ipgre_header() [1].
This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ipgre device.
[1]
skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0
kernel BUG at net/core/skbuff.c:213 !
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: mld mld_ifc_work
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
Call Trace:
<TASK>
skb_under_panic net/core/skbuff.c:223 [inline]
skb_push+0xc3/0xe0 net/core/skbuff.c:2641
ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897
dev_hard_header include/linux/netdevice.h:3436 [inline]
neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Fixes: c544193214 ("GRE: Refactor GRE tunneling code.")
Reported-by: syzbot+7c134e1c3aa3283790b9@syzkaller.appspotmail.com
Closes: https://www.spinics.net/lists/netdev/msg1147302.html
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260108190214.1667040-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
NULL pointer dereference fix.
msg_get_inq is an input field from caller to callee. Don't set it in
the callee, as the caller may not clear it on struct reuse.
This is a kernel-internal variant of msghdr only, and the only user
does reinitialize the field. So this is not critical for that reason.
But it is more robust to avoid the write, and slightly simpler code.
And it fixes a bug, see below.
Callers set msg_get_inq to request the input queue length to be
returned in msg_inq. This is equivalent to but independent from the
SO_INQ request to return that same info as a cmsg (tp->recvmsg_inq).
To reduce branching in the hot path the second also sets the msg_inq.
That is WAI.
This is a fix to commit 4d1442979e ("af_unix: don't post cmsg for
SO_INQ unless explicitly asked for"), which fixed the inverse.
Also avoid NULL pointer dereference in unix_stream_read_generic if
state->msg is NULL and msg->msg_get_inq is written. A NULL state->msg
can happen when splicing as of commit 2b514574f7 ("net: af_unix:
implement splice for stream af_unix sockets").
Also collapse two branches using a bitwise or.
Cc: stable@vger.kernel.org
Fixes: 4d1442979e ("af_unix: don't post cmsg for SO_INQ unless explicitly asked for")
Link: https://lore.kernel.org/netdev/willemdebruijn.kernel.24d8030f7a3de@gmail.com/
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260106150626.3944363-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Jakub added a warning in nf_conntrack_cleanup_net_list() to make debugging
leaked skbs/conntrack references more obvious.
syzbot reports this as triggering, and I can also reproduce this via
ip_defrag.sh selftest:
conntrack cleanup blocked for 60s
WARNING: net/netfilter/nf_conntrack_core.c:2512
[..]
conntrack clenups gets stuck because there are skbs with still hold nf_conn
references via their frag_list.
net.core.skb_defer_max=0 makes the hang disappear.
Eric Dumazet points out that skb_release_head_state() doesn't follow the
fraglist.
ip_defrag.sh can only reproduce this problem since
commit 6471658dc6 ("udp: use skb_attempt_defer_free()"), but AFAICS this
problem could happen with TCP as well if pmtu discovery is off.
The relevant problem path for udp is:
1. netns emits fragmented packets
2. nf_defrag_v6_hook reassembles them (in output hook)
3. reassembled skb is tracked (skb owns nf_conn reference)
4. ip6_output refragments
5. refragmented packets also own nf_conn reference (ip6_fragment
calls ip6_copy_metadata())
6. on input path, nf_defrag_v6_hook skips defragmentation: the
fragments already have skb->nf_conn attached
7. skbs are reassembled via ipv6_frag_rcv()
8. skb_consume_udp -> skb_attempt_defer_free() -> skb ends up
in pcpu freelist, but still has nf_conn reference.
Possible solutions:
1 let defrag engine drop nf_conn entry, OR
2 export kick_defer_list_purge() and call it from the conntrack
netns exit callback, OR
3 add skb_has_frag_list() check to skb_attempt_defer_free()
2 & 3 also solve ip_defrag.sh hang but share same drawback:
Such reassembled skbs, queued to socket, can prevent conntrack module
removal until userspace has consumed the packet. While both tcp and udp
stack do call nf_reset_ct() before placing skb on socket queue, that
function doesn't iterate frag_list skbs.
Therefore drop nf_conn entries when they are placed in defrag queue.
Keep the nf_conn entry of the first (offset 0) skb so that reassembled
skb retains nf_conn entry for sake of TX path.
Note that fixes tag is incorrect; it points to the commit introducing the
'ip_defrag.sh reproducible problem': no need to backport this patch to
every stable kernel.
Reported-by: syzbot+4393c47753b7808dac7d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/693b0fa7.050a0220.4004e.040d.GAE@google.com/
Fixes: 6471658dc6 ("udp: use skb_attempt_defer_free()")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260102140030.32367-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When the ping program uses an IPPROTO_ICMP socket to send ICMP_ECHO
messages, ICMP_MIB_OUTMSGS is counted twice.
ping_v4_sendmsg
ping_v4_push_pending_frames
ip_push_pending_frames
ip_finish_skb
__ip_make_skb
icmp_out_count(net, icmp_type); // first count
icmp_out_count(sock_net(sk), user_icmph.type); // second count
However, when the ping program uses an IPPROTO_RAW socket,
ICMP_MIB_OUTMSGS is counted correctly only once.
Therefore, the first count should be removed.
Fixes: c319b4d76b ("net: ipv4: add IPPROTO_ICMP socket kind")
Signed-off-by: yuan.gao <yuan.gao@ucloud.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20251224063145.3615282-1-yuan.gao@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Preference of nexthop with source address broke ECMP for packets with
source addresses which are not in the broadcast domain, but rather added
to loopback/dummy interfaces. Original behaviour was to balance over
nexthops while now it uses the latest nexthop from the group. To fix the
issue introduce next hop scoring system where next hops with source
address equal to requested will always have higher priority.
For the case with 198.51.100.1/32 assigned to dummy0 and routed using
192.0.2.0/24 and 203.0.113.0/24 networks:
2: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
link/ether d6:54:8a:ff:78:f5 brd ff:ff:ff:ff:ff:ff
inet 198.51.100.1/32 scope global dummy0
valid_lft forever preferred_lft forever
7: veth1@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 06:ed:98:87:6d:8a brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 192.0.2.2/24 scope global veth1
valid_lft forever preferred_lft forever
inet6 fe80::4ed:98ff:fe87:6d8a/64 scope link proto kernel_ll
valid_lft forever preferred_lft forever
9: veth3@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether ae:75:23:38:a0:d2 brd ff:ff:ff:ff:ff:ff link-netnsid 0
inet 203.0.113.2/24 scope global veth3
valid_lft forever preferred_lft forever
inet6 fe80::ac75:23ff:fe38:a0d2/64 scope link proto kernel_ll
valid_lft forever preferred_lft forever
~ ip ro list:
default
nexthop via 192.0.2.1 dev veth1 weight 1
nexthop via 203.0.113.1 dev veth3 weight 1
192.0.2.0/24 dev veth1 proto kernel scope link src 192.0.2.2
203.0.113.0/24 dev veth3 proto kernel scope link src 203.0.113.2
before:
for i in {1..255} ; do ip ro get 10.0.0.$i; done | grep veth | awk ' {print $(NF-2)}' | sort | uniq -c:
255 veth3
after:
for i in {1..255} ; do ip ro get 10.0.0.$i; done | grep veth | awk ' {print $(NF-2)}' | sort | uniq -c:
122 veth1
133 veth3
Fixes: 32607a332c ("ipv4: prefer multipath nexthop that matches source address")
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20251221192639.3911901-1-vadim.fedorenko@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
When a nexthop object is deleted, it is marked as dead and then
fib_table_flush() is called to flush all the routes that are using the
dead nexthop.
The current logic in fib_table_flush() is to only flush error routes
(e.g., blackhole) when it is called as part of network namespace
dismantle (i.e., with flush_all=true). Therefore, error routes are not
flushed when their nexthop object is deleted:
# ip link add name dummy1 up type dummy
# ip nexthop add id 1 dev dummy1
# ip route add 198.51.100.1/32 nhid 1
# ip route add blackhole 198.51.100.2/32 nhid 1
# ip nexthop del id 1
# ip route show
blackhole 198.51.100.2 nhid 1 dev dummy1
As such, they keep holding a reference on the nexthop object which in
turn holds a reference on the nexthop device, resulting in a reference
count leak:
# ip link del dev dummy1
[ 70.516258] unregister_netdevice: waiting for dummy1 to become free. Usage count = 2
Fix by flushing error routes when their nexthop is marked as dead.
IPv6 does not suffer from this problem.
Fixes: 493ced1ac4 ("ipv4: Allow routes to use nexthop objects")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Closes: https://lore.kernel.org/netdev/d943f806-4da6-4970-ac28-b9373b0e63ac@I-love.SAKURA.ne.jp/
Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20251221144829.197694-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The struct ip_tunnel_info has a flexible array member named
options that is protected by a counted_by(options_len)
attribute.
The compiler will use this information to enforce runtime bounds
checking deployed by FORTIFY_SOURCE string helpers.
As laid out in the GCC documentation, the counter must be
initialized before the first reference to the flexible array
member.
After scanning through the files that use struct ip_tunnel_info
and also refer to options or options_len, it appears the normal
case is to use the ip_tunnel_info_opts_set() helper.
Said helper would initialize options_len properly before copying
data into options, however in the GRE ERSPAN code a partial
update is done, preventing the use of the helper function.
Before this change the handling of ERSPAN traffic in GRE tunnels
would cause a kernel panic when the kernel is compiled with
GCC 15+ and having FORTIFY_SOURCE configured:
memcpy: detected buffer overflow: 4 byte write of buffer size 0
Call Trace:
<IRQ>
__fortify_panic+0xd/0xf
erspan_rcv.cold+0x68/0x83
? ip_route_input_slow+0x816/0x9d0
gre_rcv+0x1b2/0x1c0
gre_rcv+0x8e/0x100
? raw_v4_input+0x2a0/0x2b0
ip_protocol_deliver_rcu+0x1ea/0x210
ip_local_deliver_finish+0x86/0x110
ip_local_deliver+0x65/0x110
? ip_rcv_finish_core+0xd6/0x360
ip_rcv+0x186/0x1a0
Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-counted_005fby-variable-attribute
Reported-at: https://launchpad.net/bugs/2129580
Fixes: bb5e62f2d5 ("net: Add options as a flexible array to struct ip_tunnel_info")
Signed-off-by: Frode Nordahl <fnordahl@ubuntu.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251213101338.4693-1-fnordahl@ubuntu.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
We have been seeing occasional deadlocks on pernet_ops_rwsem since
September in NIPA. The stuck task was usually modprobe (often loading
a driver like ipvlan), trying to take the lock as a Writer.
lockdep does not track readers for rwsems so the read wasn't obvious
from the reports.
On closer inspection the Reader holding the lock was conntrack looping
forever in nf_conntrack_cleanup_net_list(). Based on past experience
with occasional NIPA crashes I looked thru the tests which run before
the crash and noticed that the crash follows ip_defrag.sh. An immediate
red flag. Scouring thru (de)fragmentation queues reveals skbs sitting
around, holding conntrack references.
The problem is that since conntrack depends on nf_defrag_ipv6,
nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its
netns exit hooks run _after_ conntrack's netns exit hook.
Flush all fragment queue SKBs during fqdir_pre_exit() to release
conntrack references before conntrack cleanup runs. Also flush
the queues in timer expiry handlers when they discover fqdir->dead
is set, in case packet sneaks in while we're running the pre_exit
flush.
The commit under Fixes is not exactly the culprit, but I think
previously the timer firing would eventually unblock the spinning
conntrack.
Fixes: d5dd88794a ("inet: fix various use-after-free in defrags units")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251207010942.1672972-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In ip_frag_reinit() we want to move the frag timeout timer into
the future. If the timer fires in the meantime we inadvertently
scheduled it again, and since the timer assumes a ref on frag_queue
we need to acquire one to balance things out.
This is technically racy, we should have acquired the reference
_before_ we touch the timer, it may fire again before we take the ref.
Avoid this entire dance by using mod_timer_pending() which only modifies
the timer if its pending (and which exists since Linux v2.6.30)
Note that this was the only place we ever took a ref on frag_queue
since Eric's conversion to RCU. So we could potentially replace
the whole refcnt field with an atomic flag and a bit more RCU.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251207010942.1672972-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 61fafbee6c ("xfrm: Determine inner GSO type from packet inner
protocol") attempted to fix GSO segmentation by reading the inner
protocol from XFRM_MODE_SKB_CB(skb)->protocol. This was incorrect
because the field holds the inner L4 protocol (TCP/UDP) instead of the
required tunnel protocol. Also, the memory location (shared by
XFRM_SKB_CB(skb) which could be overwritten by xfrm_replay_overflow())
is prone to corruption. This combination caused the kernel to select
the wrong inner mode and get the wrong address family.
The correct value is in xfrm_offload(skb)->proto, which is set from
the outer tunnel header's protocol field by esp[4|6]_gso_encap(). It
is initialized by xfrm[4|6]_tunnel_encap_add() to either IPPROTO_IPIP
or IPPROTO_IPV6, using xfrm_af2proto() and correctly reflects the
inner packet's address family.
Fixes: 61fafbee6c ("xfrm: Determine inner GSO type from packet inner protocol")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
strncpy() is deprecated [1] for NUL-terminated destination buffers
because it does not guarantee NUL termination. Replace it with strscpy()
to ensure the destination buffer is always NUL-terminated and to avoid
any additional NUL padding.
Although the identifier buffer has 252 usable bytes, strncpy() copied
only up to 251 bytes to the zero-initialized buffer, relying on the last
byte to act as an implicit NUL terminator. Switching to strscpy() avoids
this implicit behavior and does not use magic numbers.
The source string is also NUL-terminated and satisfies the
__must_be_cstr() requirement of strscpy().
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://patch.msgid.link/20251126220804.102160-2-thorsten.blum@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pablo Neira Ayuso says:
====================
Netfilter updates for net-next
The following batch contains Netfilter updates for net-next:
0) Add sanity check for maximum encapsulations in bridge vlan,
reported by the new AI robot.
1) Move the flowtable path discovery code to its own file, the
nft_flow_offload.c mixes the nf_tables evaluation with the path
discovery logic, just split this in two for clarity.
2) Consolidate flowtable xmit path by using dev_queue_xmit() and the
real device behind the layer 2 vlan/pppoe device. This allows to
inline encapsulation. After this update, hw_ifidx can be removed
since both ifidx and hw_ifidx now point to the same device.
3) Support for IPIP encapsulation in the flowtable, extend selftest
to cover for this new layer 3 offload, from Lorenzo Bianconi.
4) Push down the skb into the conncount API to fix duplicates in the
conncount list for packets with non-confirmed conntrack entries,
this is due to an optimization introduced in d265929930
("netfilter: nf_conncount: reduce unnecessary GC").
From Fernando Fernandez Mancera.
5) In conncount, disable BH when performing garbage collection
to consolidate existing behaviour in the conncount API, also
from Fernando.
6) A matching packet with a confirmed conntrack invokes GC if
conncount reaches the limit in an attempt to release slots.
This allows the existing extensions to be used for real conntrack
counting, not just limiting new connections, from Fernando.
7) Support for updating ct count objects in nf_tables, from Fernando.
8) Extend nft_flowtables.sh selftest to send IPv6 TCP traffic,
from Lorenzo Bianconi.
9) Fixes for UAPI kernel-doc documentation, from Randy Dunlap.
* tag 'nf-next-25-11-28' of git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
netfilter: nf_tables: improve UAPI kernel-doc comments
netfilter: ip6t_srh: fix UAPI kernel-doc comments format
selftests: netfilter: nft_flowtable.sh: Add the capability to send IPv6 TCP traffic
netfilter: nft_connlimit: add support to object update operation
netfilter: nft_connlimit: update the count if add was skipped
netfilter: nf_conncount: make nf_conncount_gc_list() to disable BH
netfilter: nf_conncount: rework API to use sk_buff directly
selftests: netfilter: nft_flowtable.sh: Add IPIP flowtable selftest
netfilter: flowtable: Add IPIP tx sw acceleration
netfilter: flowtable: Add IPIP rx sw acceleration
netfilter: flowtable: use tuple address to calculate next hop
netfilter: flowtable: remove hw_ifidx
netfilter: flowtable: inline pppoe encapsulation in xmit path
netfilter: flowtable: inline vlan encapsulation in xmit path
netfilter: flowtable: consolidate xmit path
netfilter: flowtable: move path discovery infrastructure to its own file
netfilter: flowtable: check for maximum number of encapsulations in bridge vlan
====================
Link: https://patch.msgid.link/20251128002345.29378-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert all the legacy code directly accessing the pp fields in net_iov
to access them through @desc in net_iov.
Signed-off-by: Byungchul Park <byungchul@sk.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Introduce sw acceleration for rx path of IPIP tunnels relying on the
netfilter flowtable infrastructure. Subsequent patches will add sw
acceleration for IPIP tunnels tx path.
This series introduces basic infrastructure to accelerate other tunnel
types (e.g. IP6IP6).
IPIP rx sw acceleration can be tested running the following scenario where
the traffic is forwarded between two NICs (eth0 and eth1) and an IPIP
tunnel is used to access a remote site (using eth1 as the underlay device):
ETH0 -- TUN0 <==> ETH1 -- [IP network] -- TUN1 (192.168.100.2)
$ip addr show
6: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:00:22:33:11:55 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.2/24 scope global eth0
valid_lft forever preferred_lft forever
7: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 00:11:22:33:11:55 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.1/24 scope global eth1
valid_lft forever preferred_lft forever
8: tun0@NONE: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000
link/ipip 192.168.1.1 peer 192.168.1.2
inet 192.168.100.1/24 scope global tun0
valid_lft forever preferred_lft forever
$ip route show
default via 192.168.100.2 dev tun0
192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.2
192.168.1.0/24 dev eth1 proto kernel scope link src 192.168.1.1
192.168.100.0/24 dev tun0 proto kernel scope link src 192.168.100.1
$nft list ruleset
table inet filter {
flowtable ft {
hook ingress priority filter
devices = { eth0, eth1 }
}
chain forward {
type filter hook forward priority filter; policy accept;
meta l4proto { tcp, udp } flow add @ft
}
}
Reproducing the scenario described above using veths I got the following
results:
- TCP stream received from the IPIP tunnel:
- net-next: (baseline) ~ 71Gbps
- net-next + IPIP flowtbale support: ~101Gbps
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
sk->sk_timer has been used for TCP keepalives.
Keepalive timers are not in fast path, we want to use sk->sk_timer
storage for retransmit timers, for better cache locality.
Create icsk->icsk_keepalive_timer and change keepalive
code to no longer use sk->sk_timer.
Added space is reclaimed in the following patch.
This includes changes to MPTCP, which was also using sk_timer.
Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer
for inet_sk_diag_fill() sake.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.18-rc7).
No conflicts, adjacent changes:
tools/testing/selftests/net/af_unix/Makefile
e1bb28bf13 ("selftest: af_unix: Add test for SO_PEEK_OFF.")
45a1cd8346 ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Steffen Klassert says:
====================
pull request (net): ipsec 2025-11-18
1) Misc fixes for xfrm_state creation/modification/deletion.
Patchset from Sabrina Dubroca.
2) Fix inner packet family determination for xfrm offloads.
From Jianbo Liu.
3) Don't push locally generated packets directly to L2 tunnel
mode offloading, they still need processing from the standard
xfrm path. From Jianbo Liu.
4) Fix memory leaks in xfrm_add_acquire for policy offloads and policy
security contexts. From Zilin Guan.
* tag 'ipsec-2025-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: fix memory leak in xfrm_add_acquire()
xfrm: Prevent locally generated packets from direct output in tunnel mode
xfrm: Determine inner GSO type from packet inner protocol
xfrm: Check inner packet family directly from skb_dst
xfrm: check all hash buckets for leftover states during netns deletion
xfrm: set err and extack on failure to create pcpu SA
xfrm: call xfrm_dev_state_delete when xfrm_state_migrate fails to add the state
xfrm: make state as DEAD before final put when migrate fails
xfrm: also call xfrm_state_delete_tunnel at destroy time for states that were never added
xfrm: drop SA reference in xfrm_state_update if dir doesn't match
====================
Link: https://patch.msgid.link/20251118085344.2199815-1-steffen.klassert@secunet.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net.ipv4.tcp_comp_sack_slack_ns current default value is too high.
When a flow has many drops (1 % or more), and small RTT, adding 100 usec
before sending SACK stalls the sender relying on getting SACK
fast enough to keep the pipe busy.
Decrease the default to 10 usec.
This is orthogonal to Congestion Control heuristics to determine
if drops are caused by congestion or not.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251114135141.3810964-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.18-rc6).
No conflicts, adjacent changes in:
drivers/net/phy/micrel.c
96a9178a29 ("net: phy: micrel: lan8814 fix reset of the QSGMII interface")
61b7ade9ba ("net: phy: micrel: Add support for non PTP SKUs for lan8814")
and a trivial one in tools/testing/selftests/drivers/net/Makefile.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The sit driver's packet transmission path calls: sit_tunnel_xmit() ->
update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called
to delete entries exceeding FNHE_RECLAIM_DEPTH+random.
The race window is between fnhe_remove_oldest() selecting fnheX for
deletion and the subsequent kfree_rcu(). During this time, the
concurrent path's __mkroute_output() -> find_exception() can fetch the
soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a
new dst using a dst_hold(). When the original fnheX is freed via RCU,
the dst reference remains permanently leaked.
CPU 0 CPU 1
__mkroute_output()
find_exception() [fnheX]
update_or_create_fnhe()
fnhe_remove_oldest() [fnheX]
rt_bind_exception() [bind dst]
RCU callback [fnheX freed, dst leak]
This issue manifests as a device reference count leak and a warning in
dmesg when unregistering the net device:
unregister_netdevice: waiting for sitX to become free. Usage count = N
Ido Schimmel provided the simple test validation method [1].
The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes().
Since rt_bind_exception() checks this field, setting it to zero prevents
the stale fnhe from being reused and bound to a new dst just before it
is freed.
[1]
ip netns add ns1
ip -n ns1 link set dev lo up
ip -n ns1 address add 192.0.2.1/32 dev lo
ip -n ns1 link add name dummy1 up type dummy
ip -n ns1 route add 192.0.2.2/32 dev dummy1
ip -n ns1 link add name gretap1 up arp off type gretap \
local 192.0.2.1 remote 192.0.2.2
ip -n ns1 route add 198.51.0.0/16 dev gretap1
taskset -c 0 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
taskset -c 2 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
sleep 10
ip netns pids ns1 | xargs kill
ip netns del ns1
Cc: stable@vger.kernel.org
Fixes: 67d6d681e1 ("ipv4: make exception cache less predictible")
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251111064328.24440-1-nashuiliang@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The introduction of IPPROTO_SMC enables eBPF programs to determine
whether to use SMC based on the context of socket creation, such as
network namespaces, PID and comm name, etc.
As a subsequent enhancement, to introduce a new generic hook that
allows decisions on whether to use SMC or not at runtime, including
but not limited to local/remote IP address or ports.
User can write their own implememtion via bpf_struct_ops now to choose
whether to use SMC or not before TCP 3rd handshake to be comleted.
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20251107035632.115950-3-alibuda@linux.alibaba.com
TCP SACK compression has been added in 2018 in commit
5d9f4262b7 ("tcp: add SACK compression").
It is working great for WAN flows (with large RTT).
Wifi in particular gets a significant boost _when_ ACK are suppressed.
Add a new sysctl so that we can tune the very conservative 5 % value
that has been used so far in this formula, so that small RTT flows
can benefit from this feature.
delay = min ( 5 % of RTT, 1 ms)
This patch adds new tcp_comp_sack_rtt_percent sysctl
to ease experiments and tuning.
Given that we cap the delay to 1ms (tcp_comp_sack_delay_ns sysctl),
set the default value to 33 %.
Quoting Neal Cardwell ( https://lore.kernel.org/netdev/CADVnQymZ1tFnEA1Q=vtECs0=Db7zHQ8=+WCQtnhHFVbEOzjVnQ@mail.gmail.com/ )
The rationale for 33% is basically to try to facilitate pipelining,
where there are always at least 3 ACKs and 3 GSO/TSO skbs per SRTT, so
that the path can maintain a budget for 3 full-sized GSO/TSO skbs "in
flight" at all times:
+ 1 skb in the qdisc waiting to be sent by the NIC next
+ 1 skb being sent by the NIC (being serialized by the NIC out onto the wire)
+ 1 skb being received and aggregated by the receiver machine's
aggregation mechanism (some combination of LRO, GRO, and sack
compression)
Note that this is basically the same magic number (3) and the same
rationales as:
(a) tcp_tso_should_defer() ensuring that we defer sending data for no
longer than cwnd/tcp_tso_win_divisor (where tcp_tso_win_divisor = 3),
and
(b) bbr_quantization_budget() ensuring that cwnd is at least 3 GSO/TSO
skbs to maintain pipelining and full throughput at low RTTs
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251106115236.3450026-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 5903123f66 ("tcp: Use BPF timeout setting for SYN ACK
RTO") introduced req->timeout and initialised it in 3 places:
1. reqsk_alloc() sets 0
2. inet_reqsk_alloc() sets TCP_TIMEOUT_INIT
3. tcp_conn_request() sets tcp_timeout_init()
1. has been always redundant as 2. overwrites it immediately.
2. was necessary for TFO SYN+ACK but is no longer needed after
commit 8ea731d4c2 ("tcp: Make SYN ACK RTO tunable by BPF
programs with TFO").
3. was moved to reqsk_queue_hash_req() in the previous patch.
Now, we always initialise req->timeout just before scheduling
the SYN+ACK timer:
* For non-TFO SYN+ACK : reqsk_queue_hash_req()
* For TFO SYN+ACK : tcp_fastopen_create_child()
Let's remove the redundant initialisation of req->timeout in
reqsk_alloc() and inet_reqsk_alloc().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Revert struct sockaddr from flexible array to fixed 14-byte "sa_data",
to solve over 36,000 -Wflex-array-member-not-at-end warnings, since
struct sockaddr is embedded within many network structs.
With socket/proto sockaddr-based internal APIs switched to use struct
sockaddr_unsized, there should be no more uses of struct sockaddr that
depend on reading beyond the end of struct sockaddr::sa_data that might
trigger bounds checking.
Comparing an x86_64 "allyesconfig" vmlinux build before and after this
patch showed no new "ud1" instructions from CONFIG_UBSAN_BOUNDS nor any
new "field-spanning" memcpy CONFIG_FORTIFY_SOURCE instrumentations.
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-8-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert struct proto pre_connect(), connect(), bind(), and bind_add()
callback function prototypes from struct sockaddr to struct sockaddr_unsized.
This does not change per-implementation use of sockaddr for passing around
an arbitrarily sized sockaddr struct. Those will be addressed in future
patches.
Additionally removes the no longer referenced struct sockaddr from
include/net/inet_common.h.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Update all struct proto_ops connect() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Update all struct proto_ops bind() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The GSO segmentation functions for ESP tunnel mode
(xfrm4_tunnel_gso_segment and xfrm6_tunnel_gso_segment) were
determining the inner packet's L2 protocol type by checking the static
x->inner_mode.family field from the xfrm state.
This is unreliable. In tunnel mode, the state's actual inner family
could be defined by x->inner_mode.family or by
x->inner_mode_iaf.family. Checking only the former can lead to a
mismatch with the actual packet being processed, causing GSO to create
segments with the wrong L2 header type.
This patch fixes the bug by deriving the inner mode directly from the
packet's inner protocol stored in XFRM_MODE_SKB_CB(skb)->protocol.
Instead of replicating the code, this patch modifies the
xfrm_ip2inner_mode helper function. It now correctly returns
&x->inner_mode if the selector family (x->sel.family) is already
specified, thereby handling both specific and AF_UNSPEC cases
appropriately.
With this change, ESP GSO can use xfrm_ip2inner_mode to get the
correct inner mode. It doesn't affect existing callers, as the updated
logic now mirrors the checks they were already performing externally.
Fixes: 26dbd66eab ("esp: choose the correct inner protocol for GSO on inter address family tunnels")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Add the ability to append the incoming IP interface information to
ICMPv4 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.ipv4.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 __icmp_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).
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251027082232.232571-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Function udp_v4_early_demux() was already declared in 'include/net/udp.h',
no need to keep the extern in 'ip_input.c', which may produce the
following checkpatch warning:
WARNING: externs should be avoided in .c files
#45: FILE: net/ipv4/ip_input.c:322:
+enum skb_drop_reason udp_v4_early_demux(struct sk_buff *skb);
Replace it by including 'net/udp.h'. Do the same for tcp_v4_early_demux().
Signed-off-by: Wang Liang <wangliang74@huawei.com>
Link: https://patch.msgid.link/20251025092637.1020960-1-wangliang74@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
