kernel/linux.git/include/net/neighbour.h, branch v6.12.80

neighbour: add support for NUD_PERMANENT proxy entries

2025-08-20T16:30:37+00:00

[ Upstream commit c7d78566bbd30544a0618a6ffbc97bc0ddac7035 ] As discussesd before in [0] proxy entries (which are more configuration than runtime data) should stay when the link (carrier) goes does down. This is what happens for regular neighbour entries. So lets fix this by: - storing in proxy entries the fact that it was added as NUD_PERMANENT - not removing NUD_PERMANENT proxy entries when the carrier goes down (same as how it's done in neigh_flush_dev() for regular neigh entries) [0]: https://lore.kernel.org/netdev/c584ef7e-6897-01f3-5b80-12b53f7b4bf4@kernel.org/ Signed-off-by: Nicolas Escande Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250617141334.3724863-1-nico.escande@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29+00:00

const qualify the struct ctl_table argument in the proc_handler function signatures. This is a prerequisite to moving the static ctl_table structs into .rodata data which will ensure that proc_handler function pointers cannot be modified. This patch has been generated by the following coccinelle script: ``` virtual patch @r1@ identifier ctl, write, buffer, lenp, ppos; identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)"; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos); @r2@ identifier func, ctl, write, buffer, lenp, ppos; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int write, void *buffer, size_t *lenp, loff_t *ppos) { ... } @r3@ identifier func; @@ int func( - struct ctl_table * + const struct ctl_table * ,int , void *, size_t *, loff_t *); @r4@ identifier func, ctl; @@ int func( - struct ctl_table *ctl + const struct ctl_table *ctl ,int , void *, size_t *, loff_t *); @r5@ identifier func, write, buffer, lenp, ppos; @@ int func( - struct ctl_table * + const struct ctl_table * ,int write, void *buffer, size_t *lenp, loff_t *ppos); ``` * Code formatting was adjusted in xfs_sysctl.c to comply with code conventions. The xfs_stats_clear_proc_handler, xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where adjusted. * The ctl_table argument in proc_watchdog_common was const qualified. This is called from a proc_handler itself and is calling back into another proc_handler, making it necessary to change it as part of the proc_handler migration. Co-developed-by: Thomas Weißschuh Signed-off-by: Thomas Weißschuh Co-developed-by: Joel Granados Signed-off-by: Joel Granados

neighbour: Fix __randomize_layout crash in struct neighbour

2023-11-28T11:18:29+00:00

Previously, one-element and zero-length arrays were treated as true flexible arrays, even though they are actually "fake" flex arrays. The __randomize_layout would leave them untouched at the end of the struct, similarly to proper C99 flex-array members. However, this approach changed with commit 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays"). Now, only C99 flexible-array members will remain untouched at the end of the struct, while one-element and zero-length arrays will be subject to randomization. Fix a `__randomize_layout` crash in `struct neighbour` by transforming zero-length array `primary_key` into a proper C99 flexible-array member. Fixes: 1ee60356c2dc ("gcc-plugins: randstruct: Only warn about true flexible arrays") Closes: https://lore.kernel.org/linux-hardening/20231124102458.GB1503258@e124191.cambridge.arm.com/ Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook Tested-by: Joey Gouly Link: https://lore.kernel.org/r/ZWJoRsJGnCPdJ3+2@work Signed-off-by: Paolo Abeni

neighbour: fix data-races around n->output

2023-10-01T16:14:37+00:00

n->output field can be read locklessly, while a writer might change the pointer concurrently. Add missing annotations to prevent load-store tearing. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Signed-off-by: David S. Miller

neighbour: Remove unused function declaration pneigh_for_each()

2023-08-07T07:53:54+00:00

pneigh_for_each() is never implemented since the beginning of git history. Signed-off-by: Yue Haibing Reviewed-by: David Ahern Signed-off-by: David S. Miller

neighbour: fix unaligned access to pneigh_entry

2023-06-02T04:36:37+00:00

After the blamed commit, the member key is longer 4-byte aligned. On platforms that do not support unaligned access, e.g., MIPS32R2 with unaligned_action set to 1, this will trigger a crash when accessing an IPv6 pneigh_entry, as the key is cast to an in6_addr pointer. Change the type of the key to u32 to make it aligned. Fixes: 62dd93181aaa ("[IPV6] NDISC: Set per-entry is_router flag in Proxy NA.") Signed-off-by: Qingfang DENG Link: https://lore.kernel.org/r/20230601015432.159066-1-dqfext@gmail.com Signed-off-by: Jakub Kicinski

neighbour: switch to standard rcu, instead of rcu_bh

2023-03-22T04:32:18+00:00

rcu_bh is no longer a win, especially for objects freed with standard call_rcu(). Switch neighbour code to no longer disable BH when not necessary. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski

neighbour: annotate lockless accesses to n->nud_state

2023-03-15T07:37:32+00:00

We have many lockless accesses to n->nud_state. Before adding another one in the following patch, add annotations to readers and writers. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Reviewed-by: Martin KaFai Lau Signed-off-by: Jakub Kicinski

neighbour: delete neigh_lookup_nodev as not used

2023-03-10T07:25:26+00:00

neigh_lookup_nodev isn't used in the kernel after removal of DECnet. So let's remove it. Fixes: 1202cdd66531 ("Remove DECnet support from kernel") Signed-off-by: Leon Romanovsky Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://lore.kernel.org/r/eb5656200d7964b2d177a36b77efa3c597d6d72d.1678267343.git.leonro@nvidia.com Signed-off-by: Jakub Kicinski

net: neigh: decrement the family specific qlen

2022-11-18T10:29:50+00:00

Commit 0ff4eb3d5ebb ("neighbour: make proxy_queue.qlen limit per-device") introduced the length counter qlen in struct neigh_parms. There are separate neigh_parms instances for IPv4/ARP and IPv6/ND, and while the family specific qlen is incremented in pneigh_enqueue(), the mentioned commit decrements always the IPv4/ARP specific qlen, regardless of the currently processed family, in pneigh_queue_purge() and neigh_proxy_process(). As a result, with IPv6/ND, the family specific qlen is only incremented (and never decremented) until it exceeds PROXY_QLEN, and then, according to the check in pneigh_enqueue(), neighbor solicitations are not answered anymore. As an example, this is noted when using the subnet-router anycast address to access a Linux router. After a certain amount of time (in the observed case, qlen exceeded PROXY_QLEN after two days), the Linux router stops answering neighbor solicitations for its subnet-router anycast address and effectively becomes unreachable. Another result with IPv6/ND is that the IPv4/ARP specific qlen is decremented more often than incremented. This leads to negative qlen values, as a signed integer has been used for the length counter qlen, and potentially to an integer overflow. Fix this by introducing the helper function neigh_parms_qlen_dec(), which decrements the family specific qlen. Thereby, make use of the existing helper function neigh_get_dev_parms_rcu(), whose definition therefore needs to be placed earlier in neighbour.c. Take the family member from struct neigh_table to determine the currently processed family and appropriately call neigh_parms_qlen_dec() from pneigh_queue_purge() and neigh_proxy_process(). Additionally, use an unsigned integer for the length counter qlen. Fixes: 0ff4eb3d5ebb ("neighbour: make proxy_queue.qlen limit per-device") Signed-off-by: Thomas Zeitlhofer Signed-off-by: David S. Miller