tcp_gro_pull_header() is used in GRO fast path, inline it.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251113140358.58242-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Since commit 54a378f43425 ("tcp: add the ability to control
max RTO"), TFO SYN+ACK RTO is capped by the TFO full sk's
inet_csk(sk)->icsk_rto_max.

The value is inherited from the parent listener.

Let's apply the same cap to non-TFO SYN+ACK.

Note that req->rsk_listener is always non-NULL when we call
tcp_reqsk_timeout() in reqsk_timer_handler() or tcp_check_req().

It could be NULL for SYN cookie req, but we do not use
req->timeout then.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-6-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

reqsk_timeout() is always called with @timeout being TCP_RTO_MAX.

Let's remove the arg.

As a prep for the next patch, reqsk_timeout() is moved to tcp.h
and renamed to tcp_reqsk_timeout().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251106003357.273403-5-kuniyu@google.com
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>

Cross-merge networking fixes after downstream PR (net-6.18-rc4).

No conflicts, adjacent changes:

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
  ded9813d17d3 ("net: stmmac: Consider Tx VLAN offload tag length for maxSDU")
  26ab9830beab ("net: stmmac: replace has_xxxx with core_type")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch has no functional change, and prepares the following one.

tcp_rcvbuf_grow() will need to have access to tp->rcvq_space.space
old and new values.

Change mptcp_rcvbuf_grow() in a similar way.

Signed-off-by: Eric Dumazet <edumazet@google.com>
[ Moved 'oldval' declaration to the next patch to avoid warnings at
 build time. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-3-74b43ba4c84c@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Martin KaFai Lau says:

====================
pull-request: bpf-next 2025-10-16

We've added 6 non-merge commits during the last 1 day(s) which contain
a total of 18 files changed, 577 insertions(+), 38 deletions(-).

The main changes are:

1) Bypass the global per-protocol memory accounting either by setting
   a netns sysctl or using bpf_setsockopt in a bpf program,
   from Kuniyuki Iwashima.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  selftests/bpf: Add test for sk->sk_bypass_prot_mem.
  bpf: Introduce SK_BPF_BYPASS_PROT_MEM.
  bpf: Support bpf_setsockopt() for BPF_CGROUP_INET_SOCK_CREATE.
  net: Introduce net.core.bypass_prot_mem sysctl.
  net: Allow opt-out from global protocol memory accounting.
  tcp: Save lock_sock() for memcg in inet_csk_accept().
====================

Link: https://patch.msgid.link/20251016204539.773707-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Make tcp-md5 use the MD5 library API (added in 6.18) instead of the
crypto_ahash API.  This is much simpler and also more efficient:

- The library API just operates on struct md5_ctx.  Just allocate this
  struct on the stack instead of using a pool of pre-allocated
  crypto_ahash and ahash_request objects.

- The library API accepts standard pointers and doesn't require
  scatterlists.  So, for hashing the headers just use an on-stack buffer
  instead of a pool of pre-allocated kmalloc'ed scratch buffers.

- The library API never fails.  Therefore, checking for MD5 hashing
  errors is no longer necessary.  Update tcp_v4_md5_hash_skb(),
  tcp_v6_md5_hash_skb(), tcp_v4_md5_hash_hdr(), tcp_v6_md5_hash_hdr(),
  tcp_md5_hash_key(), tcp_sock_af_ops::calc_md5_hash, and
  tcp_request_sock_ops::calc_md5_hash to return void instead of int.

- The library API provides direct access to the MD5 code, eliminating
  unnecessary overhead such as indirect function calls and scatterlist
  management.  Microbenchmarks of tcp_v4_md5_hash_skb() on x86_64 show a
  speedup from 7518 to 7041 cycles (6% fewer) with skb->len == 1440, or
  from 1020 to 678 cycles (33% fewer) with skb->len == 140.

Since tcp_sigpool_hash_skb_data() can no longer be used, add a function
tcp_md5_hash_skb_data() which is specialized to MD5.  Of course, to the
extent that this duplicates any code, it's well worth it.

To preserve the existing behavior of TCP-MD5 support being disabled when
the kernel is booted with "fips=1", make tcp_md5_do_add() check
fips_enabled itself.  Previously it relied on the error from
crypto_alloc_ahash("md5") being bubbled up.  I don't know for sure that
this is actually needed, but this preserves the existing behavior.

Tested with bidirectional TCP-MD5, both IPv4 and IPv6, between a kernel
that includes this commit and a kernel that doesn't include this commit.

(Side note: please don't use TCP-MD5!  It's cryptographically weak.  But
as long as Linux supports it, it might as well be implemented properly.)

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20251014215836.115616-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Some protocols (e.g., TCP, UDP) implement memory accounting for socket
buffers and charge memory to per-protocol global counters pointed to by
sk->sk_proto->memory_allocated.

Sometimes, system processes do not want that limitation.  For a similar
purpose, there is SO_RESERVE_MEM for sockets under memcg.

Also, by opting out of the per-protocol accounting, sockets under memcg
can avoid paying costs for two orthogonal memory accounting mechanisms.
A microbenchmark result is in the subsequent bpf patch.

Let's allow opt-out from the per-protocol memory accounting if
sk->sk_bypass_prot_mem is true.

sk->sk_bypass_prot_mem and sk->sk_prot are placed in the same cache
line, and sk_has_account() always fetches sk->sk_prot before accessing
sk->sk_bypass_prot_mem, so there is no extra cache miss for this patch.

The following patches will set sk->sk_bypass_prot_mem to true, and
then, the per-protocol memory accounting will be skipped.

Note that this does NOT disable memcg, but rather the per-protocol one.

Another option not to use the hole in struct sock_common is create
sk_prot variants like tcp_prot_bypass, but this would complicate
SOCKMAP logic, tcp_bpf_prots etc.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://patch.msgid.link/20251014235604.3057003-3-kuniyu@google.com

Some applications uses TCP_TX_DELAY socket option after TCP flow
is established.

Some metrics need to be updated, otherwise TCP might take time to
adapt to the new (emulated) RTT.

This patch adjusts tp->srtt_us, tp->rtt_min, icsk_rto
and sk->sk_pacing_rate.

This is best effort, and for instance icsk_rto is reset
without taking backoff into account.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251013145926.833198-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>