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inet: implement lockless IP_MINTTL

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inet->min_ttl is already read with READ_ONCE().

Implementing IP_MINTTL socket option set/read
without holding the socket lock is easy.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2023-08-16 08:15:47 +00:00 committed by David S. Miller
parent 10f42426e5
commit 12af73269f
1 changed files with 14 additions and 18 deletions
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32
net/ipv4/ip_sockglue.c
View File

@ -1030,6 +1030,17 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
return -EINVAL;
WRITE_ONCE(inet->uc_ttl, val);
return 0;
case IP_MINTTL:
if (optlen < 1)
return -EINVAL;
if (val < 0 || val > 255)
return -EINVAL;
if (val)
static_branch_enable(&ip4_min_ttl);
WRITE_ONCE(inet->min_ttl, val);
return 0;
}
err = 0;
@ -1326,21 +1337,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
err = xfrm_user_policy(sk, optname, optval, optlen);
break;
case IP_MINTTL:
if (optlen < 1)
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.
*/
WRITE_ONCE(inet->min_ttl, val);
break;
case IP_LOCAL_PORT_RANGE:
{
const __u16 lo = val;
@ -1595,6 +1591,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
if (val < 0)
val = READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_default_ttl);
goto copyval;
case IP_MINTTL:
val = READ_ONCE(inet->min_ttl);
goto copyval;
}
if (needs_rtnl)
@ -1731,9 +1730,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
len -= msg.msg_controllen;
return copy_to_sockptr(optlen, &len, sizeof(int));
}
case IP_MINTTL:
val = inet->min_ttl;
break;
case IP_LOCAL_PORT_RANGE:
val = inet->local_port_range.hi << 16 | inet->local_port_range.lo;
break;