[INET]: Generalise tcp_v4_lookup_listener

[acme@toy net-2.6.14]$ grep built-in /tmp/before /tmp/after
/tmp/before: 282560       13122    9312  304994   4a762 net/ipv4/built-in.o
/tmp/after:  282560       13122    9312  304994   4a762 net/ipv4/built-in.o

Will be used in DCCP, not exporting it right now not to get in Adrian
Bunk's exported-but-not-used-on-modules radar 8)

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 82 insertions, 76 deletions

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 6731df2cea67..1c4fa0065a8e 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -16,8 +16,10 @@
 
 #include <linux/interrupt.h>
 #include <linux/ip.h>
+#include <linux/ipv6.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <linux/socket.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
@@ -274,4 +276,38 @@ out:
         if (sk->sk_state == TCP_LISTEN)
                 wake_up(&hashinfo->lhash_wait);
 }
+
+extern struct sock *__inet_lookup_listener(const struct hlist_head *head,
+                                           const u32 daddr,
+                                           const unsigned short hnum,
+                                           const int dif);
+
+/* Optimize the common listener case. */
+static inline struct sock *inet_lookup_listener(struct inet_hashinfo *hashinfo,
+                                                const u32 daddr,
+                                                const unsigned short hnum,
+                                                const int dif)
+{
+        struct sock *sk = NULL;
+        struct hlist_head *head;
+
+        read_lock(&hashinfo->lhash_lock);
+        head = &hashinfo->listening_hash[inet_lhashfn(hnum)];
+        if (!hlist_empty(head)) {
+                const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
+
+                if (inet->num == hnum && !sk->sk_node.next &&
+                    (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
+                    (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
+                    !sk->sk_bound_dev_if)
+                        goto sherry_cache;
+                sk = __inet_lookup_listener(head, daddr, hnum, dif);
+        }
+        if (sk) {
+sherry_cache:
+                sock_hold(sk);
+        }
+        read_unlock(&hashinfo->lhash_lock);
+        return sk;
+}
 #endif /* _INET_HASHTABLES_H */
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 06cbc6f689c5..88fcba05b7d6 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -121,3 +121,44 @@ void inet_listen_wlock(struct inet_hashinfo *hashinfo)
 }
 
 EXPORT_SYMBOL(inet_listen_wlock);
+
+/*
+ * Don't inline this cruft. Here are some nice properties to exploit here. The
+ * BSD API does not allow a listening sock to specify the remote port nor the
+ * remote address for the connection. So always assume those are both
+ * wildcarded during the search since they can never be otherwise.
+ */
+struct sock *__inet_lookup_listener(const struct hlist_head *head, const u32 daddr,
+                                    const unsigned short hnum, const int dif)
+{
+        struct sock *result = NULL, *sk;
+        const struct hlist_node *node;
+        int hiscore = -1;
+
+        sk_for_each(sk, node, head) {
+                const struct inet_sock *inet = inet_sk(sk);
+
+                if (inet->num == hnum && !ipv6_only_sock(sk)) {
+                        const __u32 rcv_saddr = inet->rcv_saddr;
+                        int score = sk->sk_family == PF_INET ? 1 : 0;
+
+                        if (rcv_saddr) {
+                                if (rcv_saddr != daddr)
+                                        continue;
+                                score += 2;
+                        }
+                        if (sk->sk_bound_dev_if) {
+                                if (sk->sk_bound_dev_if != dif)
+                                        continue;
+                                score += 2;
+                        }
+                        if (score == 5)
+                                return sk;
+                        if (score > hiscore) {
+                                hiscore = score;
+                                result  = sk;
+                        }
+                }
+        }
+        return result;
+}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index dca1be67164b..a678709b36f6 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -238,78 +238,6 @@ void tcp_unhash(struct sock *sk)
         inet_unhash(&tcp_hashinfo, sk);
 }
 
-/* Don't inline this cruft.  Here are some nice properties to
- * exploit here.  The BSD API does not allow a listening TCP
- * to specify the remote port nor the remote address for the
- * connection.  So always assume those are both wildcarded
- * during the search since they can never be otherwise.
- */
-static struct sock *__tcp_v4_lookup_listener(struct hlist_head *head,
-                                             const u32 daddr,
-                                             const unsigned short hnum,
-                                             const int dif)
-{
-        struct sock *result = NULL, *sk;
-        struct hlist_node *node;
-        int score, hiscore;
-
-        hiscore=-1;
-        sk_for_each(sk, node, head) {
-                struct inet_sock *inet = inet_sk(sk);
-
-                if (inet->num == hnum && !ipv6_only_sock(sk)) {
-                        __u32 rcv_saddr = inet->rcv_saddr;
-
-                        score = (sk->sk_family == PF_INET ? 1 : 0);
-                        if (rcv_saddr) {
-                                if (rcv_saddr != daddr)
-                                        continue;
-                                score+=2;
-                        }
-                        if (sk->sk_bound_dev_if) {
-                                if (sk->sk_bound_dev_if != dif)
-                                        continue;
-                                score+=2;
-                        }
-                        if (score == 5)
-                                return sk;
-                        if (score > hiscore) {
-                                hiscore = score;
-                                result = sk;
-                        }
-                }
-        }
-        return result;
-}
-
-/* Optimize the common listener case. */
-static inline struct sock *tcp_v4_lookup_listener(const u32 daddr,
-                                                  const unsigned short hnum,
-                                                  const int dif)
-{
-        struct sock *sk = NULL;
-        struct hlist_head *head;
-
-        read_lock(&tcp_hashinfo.lhash_lock);
-        head = &tcp_hashinfo.listening_hash[inet_lhashfn(hnum)];
-        if (!hlist_empty(head)) {
-                struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
-
-                if (inet->num == hnum && !sk->sk_node.next &&
-                    (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
-                    (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
-                    !sk->sk_bound_dev_if)
-                        goto sherry_cache;
-                sk = __tcp_v4_lookup_listener(head, daddr, hnum, dif);
-        }
-        if (sk) {
-sherry_cache:
-                sock_hold(sk);
-        }
-        read_unlock(&tcp_hashinfo.lhash_lock);
-        return sk;
-}
-
 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  *
@@ -358,7 +286,7 @@ static inline struct sock *__tcp_v4_lookup(u32 saddr, u16 sport,
         struct sock *sk = __tcp_v4_lookup_established(saddr, sport,
                                                       daddr, hnum, dif);
 
-        return sk ? : tcp_v4_lookup_listener(daddr, hnum, dif);
+        return sk ? : inet_lookup_listener(&tcp_hashinfo, daddr, hnum, dif);
 }
 
 inline struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr,
@@ -1641,9 +1569,10 @@ do_time_wait:
         switch (tcp_timewait_state_process((struct tcp_tw_bucket *)sk,
                                            skb, th, skb->len)) {
         case TCP_TW_SYN: {
-                struct sock *sk2 = tcp_v4_lookup_listener(skb->nh.iph->daddr,
-                                                          ntohs(th->dest),
-                                                          tcp_v4_iif(skb));
+                struct sock *sk2 = inet_lookup_listener(&tcp_hashinfo,
+                                                        skb->nh.iph->daddr,
+                                                        ntohs(th->dest),
+                                                        tcp_v4_iif(skb));
                 if (sk2) {
                         tcp_tw_deschedule((struct tcp_tw_bucket *)sk);
                         tcp_tw_put((struct tcp_tw_bucket *)sk);