ipv4: Add a socket release callback for datagram sockets

This implements a socket release callback function to check if the socket cached route got invalid during the time we owned the socket. The function is used from udp, raw and ping sockets. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>

ipv4: Add a socket release callback for datagram sockets
This implements a socket release callback function to check if the socket cached route got invalid during the time we owned the socket. The function is used from udp, raw and ping sockets. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Steffen Klassert · David S. Miller · Eric Lee · Eric Lee · Eric Lee · Eric Lee
1 parent 9cb3a50c5f
Showing 5 changed files with 30 additions and 0 deletions Side-by-side Diff
include/net/ip.h
net/ipv4/datagram.c
net/ipv4/ping.c
net/ipv4/raw.c
net/ipv4/udp.c
@@ -143,6 +143,8 @@
 extern int		ip4_datagram_connect(struct sock *sk, 
 					     struct sockaddr *uaddr, int addr_len);
  
+extern void ip4_datagram_release_cb(struct sock *sk);
+
 struct ip_reply_arg {
 	struct kvec iov[1];   
 	int	    flags;
@@ -85,4 +85,29 @@
 	return err;
 }
 EXPORT_SYMBOL(ip4_datagram_connect);
+
+void ip4_datagram_release_cb(struct sock *sk)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct ip_options_rcu *inet_opt;
+	__be32 daddr = inet->inet_daddr;
+	struct flowi4 fl4;
+	struct rtable *rt;
+
+	if (! __sk_dst_get(sk) || __sk_dst_check(sk, 0))
+		return;
+
+	rcu_read_lock();
+	inet_opt = rcu_dereference(inet->inet_opt);
+	if (inet_opt && inet_opt->opt.srr)
+		daddr = inet_opt->opt.faddr;
+	rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
+				   inet->inet_saddr, inet->inet_dport,
+				   inet->inet_sport, sk->sk_protocol,
+				   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
+	if (!IS_ERR(rt))
+		__sk_dst_set(sk, &rt->dst);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);
@@ -738,6 +738,7 @@
 	.recvmsg =	ping_recvmsg,
 	.bind =		ping_bind,
 	.backlog_rcv =	ping_queue_rcv_skb,
+	.release_cb =	ip4_datagram_release_cb,
 	.hash =		ping_v4_hash,
 	.unhash =	ping_v4_unhash,
 	.get_port =	ping_v4_get_port,
@@ -894,6 +894,7 @@
 	.recvmsg	   = raw_recvmsg,
 	.bind		   = raw_bind,
 	.backlog_rcv	   = raw_rcv_skb,
+	.release_cb	   = ip4_datagram_release_cb,
 	.hash		   = raw_hash_sk,
 	.unhash		   = raw_unhash_sk,
 	.obj_size	   = sizeof(struct raw_sock),
@@ -1952,6 +1952,7 @@
 	.recvmsg	   = udp_recvmsg,
 	.sendpage	   = udp_sendpage,
 	.backlog_rcv	   = __udp_queue_rcv_skb,
+	.release_cb	   = ip4_datagram_release_cb,
 	.hash		   = udp_lib_hash,
 	.unhash		   = udp_lib_unhash,
 	.rehash		   = udp_v4_rehash,
...	...	@@ -143,6 +143,8 @@
143	143	extern int ip4_datagram_connect(struct sock *sk,
144	144	struct sockaddr *uaddr, int addr_len);
145	145
	146	+extern void ip4_datagram_release_cb(struct sock *sk);
	147	+
146	148	struct ip_reply_arg {
147	149	struct kvec iov[1];
148	150	int flags;
...	...	@@ -85,4 +85,29 @@
85	85	return err;
86	86	}
87	87	EXPORT_SYMBOL(ip4_datagram_connect);
	88	+
	89	+void ip4_datagram_release_cb(struct sock *sk)
	90	+{
	91	+ const struct inet_sock *inet = inet_sk(sk);
	92	+ const struct ip_options_rcu *inet_opt;
	93	+ __be32 daddr = inet->inet_daddr;
	94	+ struct flowi4 fl4;
	95	+ struct rtable *rt;
	96	+
	97	+ if (! __sk_dst_get(sk) \|\| __sk_dst_check(sk, 0))
	98	+ return;
	99	+
	100	+ rcu_read_lock();
	101	+ inet_opt = rcu_dereference(inet->inet_opt);
	102	+ if (inet_opt && inet_opt->opt.srr)
	103	+ daddr = inet_opt->opt.faddr;
	104	+ rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
	105	+ inet->inet_saddr, inet->inet_dport,
	106	+ inet->inet_sport, sk->sk_protocol,
	107	+ RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
	108	+ if (!IS_ERR(rt))
	109	+ __sk_dst_set(sk, &rt->dst);
	110	+ rcu_read_unlock();
	111	+}
	112	+EXPORT_SYMBOL_GPL(ip4_datagram_release_cb);
...	...	@@ -738,6 +738,7 @@
738	738	.recvmsg = ping_recvmsg,
739	739	.bind = ping_bind,
740	740	.backlog_rcv = ping_queue_rcv_skb,
	741	+ .release_cb = ip4_datagram_release_cb,
741	742	.hash = ping_v4_hash,
742	743	.unhash = ping_v4_unhash,
743	744	.get_port = ping_v4_get_port,
...	...	@@ -894,6 +894,7 @@
894	894	.recvmsg = raw_recvmsg,
895	895	.bind = raw_bind,
896	896	.backlog_rcv = raw_rcv_skb,
	897	+ .release_cb = ip4_datagram_release_cb,
897	898	.hash = raw_hash_sk,
898	899	.unhash = raw_unhash_sk,
899	900	.obj_size = sizeof(struct raw_sock),
...	...	@@ -1952,6 +1952,7 @@
1952	1952	.recvmsg = udp_recvmsg,
1953	1953	.sendpage = udp_sendpage,
1954	1954	.backlog_rcv = __udp_queue_rcv_skb,
	1955	+ .release_cb = ip4_datagram_release_cb,
1955	1956	.hash = udp_lib_hash,
1956	1957	.unhash = udp_lib_unhash,
1957	1958	.rehash = udp_v4_rehash,