diff mbox series

[net-next,15/15] inet: implement lockless IP_MINTTL

Message ID 20230810103927.1705940-16-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series inet: socket lock and data-races avoidance | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 17 this patch: 17
netdev/cc_maintainers warning 1 maintainers not CCed: dsahern@kernel.org
netdev/build_clang fail Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 17 this patch: 17
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 56 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Aug. 10, 2023, 10:39 a.m. UTC 
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>
---
 net/ipv4/ip_sockglue.c | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index dbb2d2342ebf0c1f1366ee6b6b2158a6118b2659..61b2e7bc7031501ff5a3ebeffc3f90be180fa09e 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -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;