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| author | Eric Dumazet <edumazet@google.com> | 2021-10-25 09:48:24 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-10-25 18:02:14 -0700 |
| commit | 020e71a3cf7f50c0f2c54cf2444067b76fe6d785 (patch) | |
| tree | 34f7f3b49927f2807a6a72bd488328484a728e00 /net/ipv4/ip_sockglue.c | |
| parent | 14834c4f4eb3c8c0af40f6203dbf09d232044d9d (diff) | |
| download | linux-020e71a3cf7f50c0f2c54cf2444067b76fe6d785.tar.gz linux-020e71a3cf7f50c0f2c54cf2444067b76fe6d785.tar.bz2 linux-020e71a3cf7f50c0f2c54cf2444067b76fe6d785.zip | |
ipv4: guard IP_MINTTL with a static key
RFC 5082 IP_MINTTL option is rarely used on hosts.
Add a static key to remove from TCP fast path useless code,
and potential cache line miss to fetch inet_sk(sk)->min_ttl
Note that once ip4_min_ttl static key has been enabled,
it stays enabled until next boot.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/ip_sockglue.c')
| -rw-r--r-- | net/ipv4/ip_sockglue.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index d5487c858067..38d29b175ca6 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -886,6 +886,8 @@ static int compat_ip_mcast_join_leave(struct sock *sk, int optname, return ip_mc_leave_group(sk, &mreq); } +DEFINE_STATIC_KEY_FALSE(ip4_min_ttl); + static int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, unsigned int optlen) { @@ -1352,6 +1354,10 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname, goto e_inval; if (val < 0 || val > 255) goto e_inval; + + if (val) + static_branch_enable(&ip4_min_ttl); + /* tcp_v4_err() and tcp_v4_rcv() might read min_ttl * while we are changint it. */ |