kernel/linux.git/net/ipv4/inet_hashtables.c, branch linux-7.1.y

net: remove EXPORT_IPV6_MOD() and EXPORT_IPV6_MOD_GPL() macros

2026-03-29T18:21:22+00:00

As IPv6 is built-in only, the macro is always evaluating to an empty one. Remove it completely from the code. Signed-off-by: Fernando Fernandez Mancera Link: https://patch.msgid.link/20260325120928.15848-3-fmancera@suse.de Signed-off-by: Jakub Kicinski

inet: add ip_local_port_step_width sysctl to improve port usage distribution

2026-03-11T01:59:39+00:00

With the current port selection algorithm, ports after a reserved port range or long time used port are used more often than others [1]. This causes an uneven port usage distribution. This combines with cloud environments blocking connections between the application server and the database server if there was a previous connection with the same source port, leading to connectivity problems between applications on cloud environments. The real issue here is that these firewalls cannot cope with standards-compliant port reuse. This is a workaround for such situations and an improvement on the distribution of ports selected. The proposed solution is to implement a variant of RFC 6056 Algorithm 5. The step size is selected randomly on every connect() call ensuring it is a coprime with respect to the size of the range of ports we want to scan. This way, we can ensure that all ports within the range are scanned before returning an error. To enable this algorithm, the user must configure the new sysctl option "net.ipv4.ip_local_port_step_width". In addition, on graphs generated we can observe that the distribution of source ports is more even with the proposed approach. [2] [1] https://0xffsoftware.com/port_graph_current_alg.html [2] https://0xffsoftware.com/port_graph_random_step_alg.html Reviewed-by: Eric Dumazet Signed-off-by: Fernando Fernandez Mancera Link: https://patch.msgid.link/20260309023946.5473-2-fmancera@suse.de Signed-off-by: Jakub Kicinski

tcp: Initialise ehash secrets during connect() and listen().

2026-03-06T02:50:05+00:00

inet_ehashfn() and inet6_ehashfn() initialise random secrets on the first call by net_get_random_once(). While the init part is patched out using static keys, with CONFIG_STACKPROTECTOR_STRONG=y, this causes a compiler to generate a stack canary due to an automatic variable, unsigned long ___flags, in the DO_ONCE() macro being passed to __do_once_start(). With FDO, this is visible in __inet_lookup_established() and __inet6_lookup_established() too. Let's initialise the secrets by get_random_sleepable_once() in the slow paths: inet_hash() for listen(), and inet_hash_connect() and inet6_hash_connect() for connect(). Note that IPv6 listener will initialise both IPv4 & IPv6 secrets in inet_hash() for IPv4-mapped IPv6 address. With the patch, the stack size is reduced by 16 bytes (___flags + a stack canary) and NOPs for the static key go away. Before: __inet6_lookup_established() ... push %rbx sub $0x38,%rsp # stack is 56 bytes mov %edx,%ebx # sport mov %gs:0x299419f(%rip),%rax # load stack canary mov %rax,0x30(%rsp) and store it onto stack mov 0x440(%rdi),%r15 # net->ipv4.tcp_death_row.hashinfo nop 32: mov %r8d,%ebp # hnum shl $0x10,%ebp # hnum << 16 nop 3d: mov 0x70(%rsp),%r14d # sdif or %ebx,%ebp # INET_COMBINED_PORTS(sport, hnum) mov 0x11a8382(%rip),%eax # inet6_ehashfn() ... After: __inet6_lookup_established() ... push %rbx sub $0x28,%rsp # stack is 40 bytes mov 0x60(%rsp),%ebp # sdif mov %r8d,%r14d # hnum shl $0x10,%r14d # hnum << 16 or %edx,%r14d # INET_COMBINED_PORTS(sport, hnum) mov 0x440(%rdi),%rax # net->ipv4.tcp_death_row.hashinfo mov 0x1194f09(%rip),%r10d # inet6_ehashfn() ... Suggested-by: Eric Dumazet Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260303235424.3877267-1-kuniyu@google.com Signed-off-by: Jakub Kicinski

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

2026-03-05T20:11:05+00:00

Cross-merge networking fixes after downstream PR (net-7.0-rc3). No conflicts. Adjacent changes: net/netfilter/nft_set_rbtree.c fb7fb4016300 ("netfilter: nf_tables: clone set on flush only") 3aea466a4399 ("netfilter: nft_set_rbtree: don't disable bh when acquiring tree lock") Signed-off-by: Jakub Kicinski

dccp Remove inet_hashinfo2_init_mod().

2026-03-03T02:50:28+00:00

Commit c92c81df93df ("net: dccp: fix kernel crash on module load") added inet_hashinfo2_init_mod() for DCCP. Commit 22d6c9eebf2e ("net: Unexport shared functions for DCCP.") removed EXPORT_SYMBOL_GPL() it but forgot to remove the function itself. Let's remove inet_hashinfo2_init_mod(). Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260301063756.1581685-1-kuniyu@google.com Signed-off-by: Jakub Kicinski

inet: annotate data-races around isk->inet_num

2026-02-28T01:16:59+00:00

UDP/TCP lookups are using RCU, thus isk->inet_num accesses should use READ_ONCE() and WRITE_ONCE() where needed. Fixes: 3ab5aee7fe84 ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260225203545.1512417-1-edumazet@google.com Signed-off-by: Jakub Kicinski

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

inet: Avoid ehash lookup race in inet_ehash_insert()

2025-10-17T23:08:43+00:00

Since ehash lookups are lockless, if one CPU performs a lookup while another concurrently deletes and inserts (removing reqsk and inserting sk), the lookup may fail to find the socket, an RST may be sent. The call trace map is drawn as follows: CPU 0 CPU 1 ----- ----- inet_ehash_insert() spin_lock() sk_nulls_del_node_init_rcu(osk) __inet_lookup_established() (lookup failed) __sk_nulls_add_node_rcu(sk, list) spin_unlock() As both deletion and insertion operate on the same ehash chain, this patch introduces a new sk_nulls_replace_node_init_rcu() helper functions to implement atomic replacement. Fixes: 5e0724d027f0 ("tcp/dccp: fix hashdance race for passive sessions") Reviewed-by: Kuniyuki Iwashima Reviewed-by: Jiayuan Chen Signed-off-by: Xuanqiang Luo Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251015020236.431822-3-xuanqiang.luo@linux.dev Signed-off-by: Jakub Kicinski

tcp: Update bind bucket state on port release

2025-09-23T08:12:15+00:00

Today, once an inet_bind_bucket enters a state where fastreuse >= 0 or fastreuseport >= 0 after a socket is explicitly bound to a port, it remains in that state until all sockets are removed and the bucket is destroyed. In this state, the bucket is skipped during ephemeral port selection in connect(). For applications using a reduced ephemeral port range (IP_LOCAL_PORT_RANGE socket option), this can cause faster port exhaustion since blocked buckets are excluded from reuse. The reason the bucket state isn't updated on port release is unclear. Possibly a performance trade-off to avoid scanning bucket owners, or just an oversight. Fix it by recalculating the bucket state when a socket releases a port. To limit overhead, each inet_bind2_bucket stores its own (fastreuse, fastreuseport) state. On port release, only the relevant port-addr bucket is scanned, and the overall state is derived from these. Signed-off-by: Jakub Sitnicki Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250917-update-bind-bucket-state-on-unhash-v5-1-57168b661b47@cloudflare.com Signed-off-by: Paolo Abeni