inet: move inet->freebind to inet->inet_flags

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

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
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,
-				freebind:1,
 				hdrincl:1,
 				mc_loop:1,
 				transparent:1,
@@ -271,6 +270,7 @@ enum {
 
 	INET_FLAGS_RECVERR	= 9,
 	INET_FLAGS_RECVERR_RFC4884 = 10,
+	INET_FLAGS_FREEBIND	= 11,
 };
 
 /* cmsg flags for inet */
@@ -423,7 +423,8 @@ static inline bool inet_can_nonlocal_bind(struct net *net,
 					  struct inet_sock *inet)
 {
 	return READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind) ||
-		inet->freebind || inet->transparent;
+		test_bit(INET_FLAGS_FREEBIND, &inet->inet_flags) ||
+		inet->transparent;
 }
 
 static inline bool inet_addr_valid_or_nonlocal(struct net *net,

include/net/ipv6.h

@@ -937,7 +937,8 @@ static inline bool ipv6_can_nonlocal_bind(struct net *net,
 					  struct inet_sock *inet)
 {
 	return net->ipv6.sysctl.ip_nonlocal_bind ||
-		inet->freebind || inet->transparent;
+		test_bit(INET_FLAGS_FREEBIND, &inet->inet_flags) ||
+		inet->transparent;
 }
 
 /* Sysctl settings for net ipv6.auto_flowlabels */

net/ipv4/inet_diag.c

@@ -184,7 +184,7 @@ int inet_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
 	memset(&inet_sockopt, 0, sizeof(inet_sockopt));
 	inet_sockopt.recverr	= inet_test_bit(RECVERR, sk);
 	inet_sockopt.is_icsk	= inet->is_icsk;
-	inet_sockopt.freebind	= inet->freebind;
+	inet_sockopt.freebind	= inet_test_bit(FREEBIND, sk);
 	inet_sockopt.hdrincl	= inet->hdrincl;
 	inet_sockopt.mc_loop	= inet->mc_loop;
 	inet_sockopt.transparent = inet->transparent;

net/ipv4/ip_sockglue.c

@@ -608,9 +608,7 @@ EXPORT_SYMBOL(ip_sock_set_tos);
 
 void ip_sock_set_freebind(struct sock *sk)
 {
-	lock_sock(sk);
-	inet_sk(sk)->freebind = true;
-	release_sock(sk);
+	inet_set_bit(FREEBIND, sk);
 }
 EXPORT_SYMBOL(ip_sock_set_freebind);
 
@@ -985,6 +983,11 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
 			return -EINVAL;
 		inet_assign_bit(RECVERR_RFC4884, sk, val);
 		return 0;
+	case IP_FREEBIND:
+		if (optlen < 1)
+			return -EINVAL;
+		inet_assign_bit(FREEBIND, sk, val);
+		return 0;
 	}
 
 	err = 0;
@@ -1310,12 +1313,6 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname,
 		inet->mc_all = val;
 		break;
 
-	case IP_FREEBIND:
-		if (optlen < 1)
-			goto e_inval;
-		inet->freebind = !!val;
-		break;
-
 	case IP_IPSEC_POLICY:
 	case IP_XFRM_POLICY:
 		err = -EPERM;
@@ -1578,6 +1575,9 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
 	case IP_RECVERR_RFC4884:
 		val = inet_test_bit(RECVERR_RFC4884, sk);
 		goto copyval;
+	case IP_FREEBIND:
+		val = inet_test_bit(FREEBIND, sk);
+		goto copyval;
 	}
 
 	if (needs_rtnl)
@@ -1737,9 +1737,6 @@ 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_FREEBIND:
-		val = inet->freebind;
-		break;
 	case IP_TRANSPARENT:
 		val = inet->transparent;
 		break;

net/ipv6/ipv6_sockglue.c

@@ -641,7 +641,7 @@ int do_ipv6_setsockopt(struct sock *sk, int level, int optname,
 		if (optlen < sizeof(int))
 			goto e_inval;
 		/* we also don't have a separate freebind bit for IPV6 */
-		inet_sk(sk)->freebind = valbool;
+		inet_assign_bit(FREEBIND, sk, valbool);
 		retv = 0;
 		break;
 
@@ -1334,7 +1334,7 @@ int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
 		break;
 
 	case IPV6_FREEBIND:
-		val = inet_sk(sk)->freebind;
+		val = inet_test_bit(FREEBIND, sk);
 		break;
 
 	case IPV6_RECVORIGDSTADDR:

net/mptcp/sockopt.c

@@ -419,7 +419,8 @@ static int mptcp_setsockopt_v6(struct mptcp_sock *msk, int optname,
 			inet_sk(sk)->transparent = inet_sk(ssk)->transparent;
 			break;
 		case IPV6_FREEBIND:
-			inet_sk(sk)->freebind = inet_sk(ssk)->freebind;
+			inet_assign_bit(FREEBIND, sk,
+					inet_test_bit(FREEBIND, ssk));
 			break;
 		}
 
@@ -704,7 +705,7 @@ static int mptcp_setsockopt_sol_ip_set_transparent(struct mptcp_sock *msk, int o
 
 	switch (optname) {
 	case IP_FREEBIND:
-		issk->freebind = inet_sk(sk)->freebind;
+		inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
 		break;
 	case IP_TRANSPARENT:
 		issk->transparent = inet_sk(sk)->transparent;
@@ -1441,7 +1442,7 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
 	__tcp_sock_set_nodelay(ssk, !!msk->nodelay);
 
 	inet_sk(ssk)->transparent = inet_sk(sk)->transparent;
-	inet_sk(ssk)->freebind = inet_sk(sk)->freebind;
+	inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
 }
 
 static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)

net/sctp/protocol.c

@@ -360,7 +360,7 @@ static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
 	ret = inet_addr_type_table(net, addr->v4.sin_addr.s_addr, tb_id);
 	if (addr->v4.sin_addr.s_addr != htonl(INADDR_ANY) &&
 	   ret != RTN_LOCAL &&
-	   !sp->inet.freebind &&
+	   !inet_test_bit(FREEBIND, sk) &&
 	    !READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind))
 		return 0;