inet: move inet->mc_loop to inet->inet_frags

IP_MULTICAST_LOOP socket option can now be set/read
without locking the socket.

v3: fix build bot error reported in ipvs set_mcast_loop()

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>

Author: edumazet

include/net/inet_sock.h

@@ -231,7 +231,6 @@ struct inet_sock {
 	__u8			mc_ttl;
 	__u8			pmtudisc;
 	__u8			is_icsk:1,
-				mc_loop:1,
 				transparent:1,
 				mc_all:1,
 				nodefrag:1;
@@ -271,6 +270,7 @@ enum {
 	INET_FLAGS_RECVERR_RFC4884 = 10,
 	INET_FLAGS_FREEBIND	= 11,
 	INET_FLAGS_HDRINCL	= 12,
+	INET_FLAGS_MC_LOOP	= 13,
 };
 
 /* cmsg flags for inet */

net/core/sock.c

@@ -767,7 +767,7 @@ bool sk_mc_loop(struct sock *sk)
 		return true;
 	switch (sk->sk_family) {
 	case AF_INET:
-		return inet_sk(sk)->mc_loop;
+		return inet_test_bit(MC_LOOP, sk);
 #if IS_ENABLED(CONFIG_IPV6)
 	case AF_INET6:
 		return inet6_sk(sk)->mc_loop;

net/ipv4/af_inet.c

@@ -356,7 +356,7 @@ static int inet_create(struct net *net, struct socket *sock, int protocol,
 	sk->sk_txrehash = READ_ONCE(net->core.sysctl_txrehash);
 
 	inet->uc_ttl	= -1;
-	inet->mc_loop	= 1;
+	inet_set_bit(MC_LOOP, sk);
 	inet->mc_ttl	= 1;
 	inet->mc_all	= 1;
 	inet->mc_index	= 0;

net/ipv4/inet_diag.c

@@ -186,7 +186,7 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
 	inet_sockopt.is_icsk	= inet->is_icsk;
 	inet_sockopt.freebind	= inet_test_bit(FREEBIND, sk);
 	inet_sockopt.hdrincl	= inet_test_bit(HDRINCL, sk);
-	inet_sockopt.mc_loop	= inet->mc_loop;
+	inet_sockopt.mc_loop	= inet_test_bit(MC_LOOP, sk);
 	inet_sockopt.transparent = inet->transparent;
 	inet_sockopt.mc_all	= inet->mc_all;
 	inet_sockopt.nodefrag	= inet->nodefrag;

net/ipv4/ip_sockglue.c

@@ -993,6 +993,11 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
 			return -ENOPROTOOPT;
 		inet_assign_bit(HDRINCL, sk, val);
 		return 0;
+	case IP_MULTICAST_LOOP:
+		if (optlen < 1)
+			return -EINVAL;
+		inet_assign_bit(MC_LOOP, sk, val);
+		return 0;
 	}
 
 	err = 0;
@@ -1083,11 +1088,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
 			goto e_inval;
 		inet->mc_ttl = val;
 		break;
-	case IP_MULTICAST_LOOP:
-		if (optlen < 1)
-			goto e_inval;
-		inet->mc_loop = !!val;
-		break;
 	case IP_UNICAST_IF:
 	{
 		struct net_device *dev = NULL;
@@ -1579,6 +1579,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
 	case IP_HDRINCL:
 		val = inet_test_bit(HDRINCL, sk);
 		goto copyval;
+	case IP_MULTICAST_LOOP:
+		val = inet_test_bit(MC_LOOP, sk);
+		goto copyval;
 	}
 
 	if (needs_rtnl)
@@ -1653,9 +1656,6 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
 	case IP_MULTICAST_TTL:
 		val = inet->mc_ttl;
 		break;
-	case IP_MULTICAST_LOOP:
-		val = inet->mc_loop;
-		break;
 	case IP_UNICAST_IF:
 		val = (__force int)htonl((__u32) inet->uc_index);
 		break;

net/ipv4/udp_tunnel_core.c

@@ -63,7 +63,7 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
 	struct sock *sk = sock->sk;
 
 	/* Disable multicast loopback */
-	inet_sk(sk)->mc_loop = 0;
+	inet_clear_bit(MC_LOOP, sk);
 
 	/* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
 	inet_inc_convert_csum(sk);

net/ipv6/af_inet6.c

@@ -229,7 +229,7 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol,
 	 */
 	inet->uc_ttl	= -1;
 
-	inet->mc_loop	= 1;
+	inet_set_bit(MC_LOOP, sk);
 	inet->mc_ttl	= 1;
 	inet->mc_index	= 0;
 	RCU_INIT_POINTER(inet->mc_list, NULL);

net/netfilter/ipvs/ip_vs_sync.c

@@ -1297,11 +1297,9 @@ static void set_sock_size(struct sock *sk, int mode, int val)
  */
 static void set_mcast_loop(struct sock *sk, u_char loop)
 {
-	struct inet_sock *inet = inet_sk(sk);
-
 	/* setsockopt(sock, SOL_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); */
 	lock_sock(sk);
-	inet->mc_loop = loop ? 1 : 0;
+	inet_assign_bit(MC_LOOP, sk, loop);
 #ifdef CONFIG_IP_VS_IPV6
 	if (sk->sk_family == AF_INET6) {
 		struct ipv6_pinfo *np = inet6_sk(sk);

net/sctp/socket.c

@@ -9482,7 +9482,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 	newinet->inet_id = get_random_u16();
 
 	newinet->uc_ttl = inet->uc_ttl;
-	newinet->mc_loop = 1;
+	inet_set_bit(MC_LOOP, newsk);
 	newinet->mc_ttl = 1;
 	newinet->mc_index = 0;
 	newinet->mc_list = NULL;