diff options
| author | Dmitry Safonov <dima@arista.com> | 2022-11-23 18:38:57 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-12-02 00:53:05 +0100 |
| commit | 459837b522f7dff3b6681f534d8fff4eca19b7d1 (patch) | |
| tree | 2a802b4f79c2ede2bccadd155af6dfa635a71bc1 /net/ipv4/tcp_output.c | |
| parent | net/tcp: Separate tcp_md5sig_info allocation into tcp_md5sig_info_add() (diff) | |
| download | linux-459837b522f7dff3b6681f534d8fff4eca19b7d1.tar.xz linux-459837b522f7dff3b6681f534d8fff4eca19b7d1.zip | |
net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction
To do that, separate two scenarios:
- where it's the first MD5 key on the system, which means that enabling
of the static key may need to sleep;
- copying of an existing key from a listening socket to the request
socket upon receiving a signed TCP segment, where static key was
already enabled (when the key was added to the listening socket).
Now the life-time of the static branch for TCP-MD5 is until:
- last tcp_md5sig_info is destroyed
- last socket in time-wait state with MD5 key is closed.
Which means that after all sockets with TCP-MD5 keys are gone, the
system gets back the performance of disabled md5-key static branch.
While at here, provide static_key_fast_inc() helper that does ref
counter increment in atomic fashion (without grabbing cpus_read_lock()
on CONFIG_JUMP_LABEL=y). This is needed to add a new user for
a static_key when the caller controls the lifetime of another user.
Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 894410dc9293..71d01cf3c13e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -766,7 +766,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (static_branch_unlikely(&tcp_md5_needed) && + if (static_branch_unlikely(&tcp_md5_needed.key) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { @@ -922,7 +922,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (static_branch_unlikely(&tcp_md5_needed) && + if (static_branch_unlikely(&tcp_md5_needed.key) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { |