[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>

6 files changed, 117 insertions, 105 deletions

diff --git a/include/linux/ip.h b/include/linux/ip.h
index 31e7cedd9f84..33e8a19a1a0f 100644
--- a/include/linux/ip.h
+++ b/include/linux/ip.h
@@ -196,6 +196,8 @@ static inline void inet_sk_copy_descendant(struct sock *sk_to,
 #endif
 #endif
 
+extern int inet_sk_rebuild_header(struct sock *sk);
+
 struct iphdr {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
         __u8    ihl:4,
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d95661a3aeeb..0c769adb0463 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -799,8 +799,6 @@ extern void			tcp_parse_options(struct sk_buff *skb,
  *      TCP v4 functions exported for the inet6 API
  */
 
-extern int                      tcp_v4_rebuild_header(struct sock *sk);
-
 extern int                      tcp_v4_build_header(struct sock *sk, 
                                                     struct sk_buff *skb);
 
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 9e83d7773d8f..7137e6420d66 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -951,6 +951,119 @@ void inet_unregister_protosw(struct inet_protosw *p)
         }
 }
 
+/*
+ *      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,
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index c72fc878f06d..dd568b0b7062 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -83,11 +83,6 @@
 #include <linux/netlink.h>
 #include <linux/tcp.h>
 
-/*
- *      Shall we try to damage output packets if routing dev changes?
- */
-
-int sysctl_ip_dynaddr;
 int sysctl_ip_default_ttl = IPDEFTTL;
 
 /* Generate a checksum for an outgoing IP datagram. */
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 4a5daecbd2ac..ae6fad99a9a9 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1832,101 +1832,6 @@ do_time_wait:
         goto discard_it;
 }
 
-static int tcp_v4_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,
-                               IPPROTO_TCP,
-                               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 "tcp_v4_rebuild_header(): shifting inet->"
-                                 "saddr from %d.%d.%d.%d to %d.%d.%d.%d\n",
-                       NIPQUAD(old_saddr),
-                       NIPQUAD(new_saddr));
-        }
-
-        inet->saddr = new_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 tcp_v4_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 = IPPROTO_TCP,
-                                    .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);
-                return 0;
-        }
-
-        /* Routing failed... */
-        sk->sk_route_caps = 0;
-
-        if (!sysctl_ip_dynaddr ||
-            sk->sk_state != TCP_SYN_SENT ||
-            (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
-            (err = tcp_v4_reselect_saddr(sk)) != 0)
-                sk->sk_err_soft = -err;
-
-        return err;
-}
-
 static void v4_addr2sockaddr(struct sock *sk, struct sockaddr * uaddr)
 {
         struct sockaddr_in *sin = (struct sockaddr_in *) uaddr;
@@ -1998,7 +1903,7 @@ int tcp_v4_tw_remember_stamp(struct tcp_tw_bucket *tw)
 struct tcp_func ipv4_specific = {
         .queue_xmit     =       ip_queue_xmit,
         .send_check     =       tcp_v4_send_check,
-        .rebuild_header =       tcp_v4_rebuild_header,
+        .rebuild_header =       inet_sk_rebuild_header,
         .conn_request   =       tcp_v4_conn_request,
         .syn_recv_sock  =       tcp_v4_syn_recv_sock,
         .remember_stamp =       tcp_v4_remember_stamp,
@@ -2630,7 +2535,6 @@ EXPORT_SYMBOL(tcp_unhash);
 EXPORT_SYMBOL(tcp_v4_conn_request);
 EXPORT_SYMBOL(tcp_v4_connect);
 EXPORT_SYMBOL(tcp_v4_do_rcv);
-EXPORT_SYMBOL(tcp_v4_rebuild_header);
 EXPORT_SYMBOL(tcp_v4_remember_stamp);
 EXPORT_SYMBOL(tcp_v4_send_check);
 EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 885e05bd99f6..4e32a8496be3 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1983,7 +1983,7 @@ static struct tcp_func ipv6_specific = {
 static struct tcp_func ipv6_mapped = {
         .queue_xmit     =       ip_queue_xmit,
         .send_check     =       tcp_v4_send_check,
-        .rebuild_header =       tcp_v4_rebuild_header,
+        .rebuild_header =       inet_sk_rebuild_header,
         .conn_request   =       tcp_v6_conn_request,
         .syn_recv_sock  =       tcp_v6_syn_recv_sock,
         .remember_stamp =       tcp_v4_remember_stamp,