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>

diff --git a/include/net/ip.h b/include/net/ip.h
index 0707fb9551aa4c1011c88969a42cd4482450d035..a68f838a132c522df397b9398f8f2d64646008c0 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -143,6 +143,8 @@ static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 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;

diff --git a/net/ipv4/datagram.c b/net/ipv4/datagram.c
index 424fafbc8cb02c49fb2dd3551f3583290f2fc330..b28e863fe0a7143b199bee51cfdf242c125f31cf 100644 (file)
--- a/net/ipv4/datagram.c
+++ b/net/ipv4/datagram.c
@@ -85,3 +85,28 @@ out:
        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);

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 8f3d05424a3e8f2f318c36bf007fd17724533997..6f9c07268cf6d433379898421e978d74fa49952f 100644 (file)
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -738,6 +738,7 @@ struct proto ping_prot = {
        .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,

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 73d1e4df4bf630f176f385b96639b4e803469458..6f08991409c3ad9d3620357d04d1f59005f7e2fa 100644 (file)
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -894,6 +894,7 @@ struct proto raw_prot = {
        .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),

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 79c8dbe59b5474bdc3e23ba8adc227e1bee016a4..1f4d405eafba746d2b8085132a740b17a6658c80 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1952,6 +1952,7 @@ struct proto udp_prot = {
        .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,