linux/include/net/netfilter
Pablo Neira Ayuso b8b09dc2bf netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
This patch replaces the timer API by GC worker approach for
expectations, as it already happened in many other subsystems.

Use the existing conntrack GC worker to iterate over the local list of
expectations in the master conntrack to reap expired expectations.
Check IPS_HELPER_BIT to run GC for expectations, set it on for nft_ct
expectation which nevers sets it. Hold the expectation spinlock while
iterating over the master conntrack expectation list to synchronize with
nf_ct_remove_expectations(). This also performs runtime packet path
garbage collection through the expectation insertion and lookup
functions while walking over one of the chains of the global expectation
hashtables. Unconfirmed conntrack entries are skipped since ct->ext can
be reallocated and dying are skipped since those will be gone soon.
Set on IPS_HELPER_BIT if the helper ct extension is added, then the new
GC worker does not need to bump the ct refcount to check if the ct->ext
helper is available.

This removes the extra bump on the refcount for expectation timers, this
allows to remove several nf_ct_expect_put() calls after the unlink,
after this update only refcount remains at 1 while on the expectation
hashes.

This patch implicitly addresses a race with the existing timer API
allowing an expectation to access a stale exp->master pointer which has
been already released when expectation removal loses races with an
expiring timer, ie. timer_del() reporting false.

Add a new NF_CT_EXPECT_DEAD flag to reap this expectation via GC. This
is needed by nf_conntrack_unexpect_related() which is called in error
paths to invalidate newly created expectations that has been added into
the hashes. These expectactions cannot be inmediately released as GC or
nf_ct_remove_expectations() could race to make it. On expectation
insert, the runtime GC reaps stale expectations before checking the
expectation limit set by policy.

Set current timestamp in nf_ct_expect_alloc(), then add the expectation
policy timeout (or custom timeout specified added on top of this) to
specify the expectation lifetime.

Fixes: bffcaad9af ("netfilter: ctnetlink: ensure safe access to master conntrack")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
History 2026-06-21 00:18:27 +02:00
..
ipv4 netfilter: nf_conntrack_pptp: move GRE specific cleanup to GRE tracker 2026-06-05 16:16:44 +02:00
ipv6 netfilter: nf_reject: remove unneeded exports 2025-09-02 15:28:17 +02:00
br_netfilter.h netfilter: remove CONFIG_NETFILTER checks from headers. 2019-09-13 12:47:36 +02:00
nf_bpf_link.h bpf: minimal support for programs hooked into netfilter framework 2023-04-21 11:34:14 -07:00
nf_conntrack.h netfilter: nf_conntrack: don't rely on implicit includes 2026-01-20 16:23:37 +01:00
nf_conntrack_acct.h netfilter: conntrack: Remove unused function declarations 2023-08-08 13:02:00 +02:00
nf_conntrack_act_ct.h net/sched: act_ct: Always fill offloading tuple iifidx 2023-11-08 17:47:08 -08:00
nf_conntrack_bpf.h net: netfilter: move bpf_ct_set_nat_info kfunc in nf_nat_bpf.c 2022-10-03 09:17:32 -07:00
nf_conntrack_bridge.h netfilter: remove CONFIG_NETFILTER checks from headers. 2019-09-13 12:47:36 +02:00
nf_conntrack_core.h netfilter: ctnetlink: ensure safe access to master conntrack 2026-03-26 13:18:32 +01:00
nf_conntrack_count.h netfilter: nf_conncount: increase the connection clean up limit to 64 2026-01-20 16:23:37 +01:00
nf_conntrack_ecache.h netfilter: conntrack: add conntrack event timestamp 2025-01-09 14:42:16 +01:00
nf_conntrack_expect.h netfilter: nf_conntrack_expect: use conntrack GC to reap expectations 2026-06-21 00:18:27 +02:00
nf_conntrack_extend.h netfilter: conntrack: revert ct extension genid infrastructure 2026-06-05 16:16:44 +02:00
nf_conntrack_helper.h netfilter pull request 26-06-14 2026-06-15 14:09:57 -07:00
nf_conntrack_l4proto.h netfilter: conntrack: remove UDP-Lite conntrack support 2026-04-10 12:16:26 +02:00
nf_conntrack_labels.h netfilter: conntrack: switch connlabels to atomic_t 2023-10-24 13:16:30 +02:00
nf_conntrack_seqadj.h netfilter: conntrack: remove extension register api 2022-02-04 06:30:28 +01:00
nf_conntrack_synproxy.h netfilter: conntrack: wrap two inline functions in config checks. 2019-09-13 12:47:10 +02:00
nf_conntrack_timeout.h netfilter: cttimeout: detach dataplane timeout policy and repurpose refcount 2026-06-05 13:11:55 +02:00
nf_conntrack_timestamp.h netfilter: conntrack: remove extension register api 2022-02-04 06:30:28 +01:00
nf_conntrack_tuple.h netfilter: don't include xt and nftables.h in unrelated subsystems 2026-01-20 16:23:37 +01:00
nf_conntrack_zones.h netfilter: conntrack: remove CONFIG_NF_CONNTRACK checks from nf_conntrack_zones.h. 2019-09-13 12:47:41 +02:00
nf_dup_netdev.h netfilter: nf_dup_netdev: add nf_dev_xmit_recursion*() helpers and use them 2026-06-14 13:07:03 +02:00
nf_flow_table.h netfilter: flowtable: fix inline pppoe encapsulation in xmit path 2026-05-01 01:24:01 +02:00
nf_hooks_lwtunnel.h sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
nf_log.h netfilter: load nf_log_syslog on enabling nf_conntrack_log_invalid 2025-07-25 18:35:41 +02:00
nf_nat.h net: move the nat function to nf_nat_ovs for ovs and tc 2022-12-12 10:14:03 +00:00
nf_nat_helper.h netfilter: nat: move repetitive nat port reserve loop to a helper 2022-09-07 16:46:04 +02:00
nf_nat_masquerade.h netfilter: update include directives. 2019-09-13 12:33:06 +02:00
nf_nat_redirect.h netfilter: nft_redir: use struct nf_nat_range2 throughout and deduplicate eval call-backs 2023-03-22 21:48:59 +01:00
nf_queue.h netfilter: nf_queue: pin bridge device while NFQUEUE holds fake dst 2026-06-19 12:19:58 +02:00
nf_reject.h netfilter: conntrack: remove DCCP protocol support 2025-07-03 13:51:39 +02:00
nf_socket.h netfilter: Decrease code duplication regarding transparent socket option 2018-06-03 00:02:01 +02:00
nf_synproxy.h netfilter: remove CONFIG_NETFILTER checks from headers. 2019-09-13 12:47:36 +02:00
nf_tables.h netfilter: nf_tables: fix dst corruption in same register operation 2026-05-22 12:28:46 +02:00
nf_tables_core.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-09-11 17:40:13 -07:00
nf_tables_ipv4.h netfilter: nft_meta: add double-tagged vlan and pppoe support 2026-04-08 07:51:31 +02:00
nf_tables_ipv6.h netfilter: nft_meta: add double-tagged vlan and pppoe support 2026-04-08 07:51:31 +02:00
nf_tables_offload.h netfilter: nf_tables_offload: add nft_flow_action_entry_next() and use it 2026-04-08 07:51:31 +02:00
nf_tproxy.h net: reformat kdoc return statements 2024-12-09 14:44:59 -08:00
nft_fib.h netfilter: nf_tables: remove register tracking infrastructure 2026-02-25 19:36:26 -08:00
nft_meta.h netfilter: nft_meta_bridge: add validate callback for get operations 2026-06-21 00:18:26 +02:00
nft_reject.h netfilter: nf_tables: drop unused 3rd argument from validate callback ops 2024-09-03 10:47:17 +02:00
xt_rateest.h net: sched: Merge Qdisc::bstats and Qdisc::cpu_bstats data types 2021-10-18 12:54:41 +01:00