[INET]: Introduce inet_sk_rebuild_header
From tcp_v4_rebuild_header, that already was pretty generic, I only
needed to use sk->sk_protocol instead of the hardcoded IPPROTO_TCP and
establish the requirement that INET transport layer protocols that
want to use this function map TCP_SYN_SENT to its equivalent state.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 9e83d77..7137e64 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -951,6 +951,119 @@
}
}
+/*
+ * Shall we try to damage output packets if routing dev changes?
+ */
+
+int sysctl_ip_dynaddr;
+
+static int inet_sk_reselect_saddr(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ int err;
+ struct rtable *rt;
+ __u32 old_saddr = inet->saddr;
+ __u32 new_saddr;
+ __u32 daddr = inet->daddr;
+
+ if (inet->opt && inet->opt->srr)
+ daddr = inet->opt->faddr;
+
+ /* Query new route. */
+ err = ip_route_connect(&rt, daddr, 0,
+ RT_CONN_FLAGS(sk),
+ sk->sk_bound_dev_if,
+ sk->sk_protocol,
+ inet->sport, inet->dport, sk);
+ if (err)
+ return err;
+
+ sk_setup_caps(sk, &rt->u.dst);
+
+ new_saddr = rt->rt_src;
+
+ if (new_saddr == old_saddr)
+ return 0;
+
+ if (sysctl_ip_dynaddr > 1) {
+ printk(KERN_INFO "%s(): shifting inet->"
+ "saddr from %d.%d.%d.%d to %d.%d.%d.%d\n",
+ __FUNCTION__,
+ NIPQUAD(old_saddr),
+ NIPQUAD(new_saddr));
+ }
+
+ inet->saddr = inet->rcv_saddr = new_saddr;
+
+ /*
+ * XXX The only one ugly spot where we need to
+ * XXX really change the sockets identity after
+ * XXX it has entered the hashes. -DaveM
+ *
+ * Besides that, it does not check for connection
+ * uniqueness. Wait for troubles.
+ */
+ __sk_prot_rehash(sk);
+ return 0;
+}
+
+int inet_sk_rebuild_header(struct sock *sk)
+{
+ struct inet_sock *inet = inet_sk(sk);
+ struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
+ u32 daddr;
+ int err;
+
+ /* Route is OK, nothing to do. */
+ if (rt)
+ return 0;
+
+ /* Reroute. */
+ daddr = inet->daddr;
+ if (inet->opt && inet->opt->srr)
+ daddr = inet->opt->faddr;
+{
+ struct flowi fl = {
+ .oif = sk->sk_bound_dev_if,
+ .nl_u = {
+ .ip4_u = {
+ .daddr = daddr,
+ .saddr = inet->saddr,
+ .tos = RT_CONN_FLAGS(sk),
+ },
+ },
+ .proto = sk->sk_protocol,
+ .uli_u = {
+ .ports = {
+ .sport = inet->sport,
+ .dport = inet->dport,
+ },
+ },
+ };
+
+ err = ip_route_output_flow(&rt, &fl, sk, 0);
+}
+ if (!err)
+ sk_setup_caps(sk, &rt->u.dst);
+ else {
+ /* Routing failed... */
+ sk->sk_route_caps = 0;
+ /*
+ * Other protocols have to map its equivalent state to TCP_SYN_SENT.
+ * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
+ */
+ if (!sysctl_ip_dynaddr ||
+ sk->sk_state != TCP_SYN_SENT ||
+ (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
+ (err = inet_sk_reselect_saddr(sk)) != 0)
+ sk->sk_err_soft = -err;
+ }
+
+ return err;
+}
+
+EXPORT_SYMBOL(inet_sk_rebuild_header);
+
#ifdef CONFIG_IP_MULTICAST
static struct net_protocol igmp_protocol = {
.handler = igmp_rcv,