1 files changed, 42 insertions, 29 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0b5ab04d3c5a..6728772a943a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -69,6 +69,7 @@
 #include <net/transp_v6.h>
 #include <net/ipv6.h>
 #include <net/inet_common.h>
+#include <net/timewait_sock.h>
 #include <net/xfrm.h>
 
 #include <linux/inet.h>
@@ -118,6 +119,39 @@ static inline __u32 tcp_v4_init_sequence(struct sock *sk, struct sk_buff *skb)
                                           skb->h.th->source);
 }
 
+int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
+{
+        const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
+        struct tcp_sock *tp = tcp_sk(sk);
+
+        /* With PAWS, it is safe from the viewpoint
+           of data integrity. Even without PAWS it is safe provided sequence
+           spaces do not overlap i.e. at data rates <= 80Mbit/sec.
+
+           Actually, the idea is close to VJ's one, only timestamp cache is
+           held not per host, but per port pair and TW bucket is used as state
+           holder.
+
+           If TW bucket has been already destroyed we fall back to VJ's scheme
+           and use initial timestamp retrieved from peer table.
+         */
+        if (tcptw->tw_ts_recent_stamp &&
+            (twp == NULL || (sysctl_tcp_tw_reuse &&
+                             xtime.tv_sec - tcptw->tw_ts_recent_stamp > 1))) {
+                tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
+                if (tp->write_seq == 0)
+                        tp->write_seq = 1;
+                tp->rx_opt.ts_recent       = tcptw->tw_ts_recent;
+                tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
+                sock_hold(sktw);
+                return 1;
+        }
+
+        return 0;
+}
+
+EXPORT_SYMBOL_GPL(tcp_twsk_unique);
+
 /* called with local bh disabled */
 static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
                                       struct inet_timewait_sock **twp)
@@ -142,35 +176,9 @@ static int __tcp_v4_check_established(struct sock *sk, __u16 lport,
                 tw = inet_twsk(sk2);
 
                 if (INET_TW_MATCH(sk2, hash, acookie, saddr, daddr, ports, dif)) {
-                        const struct tcp_timewait_sock *tcptw = tcp_twsk(sk2);
-                        struct tcp_sock *tp = tcp_sk(sk);
-
-                        /* With PAWS, it is safe from the viewpoint
-                           of data integrity. Even without PAWS it
-                           is safe provided sequence spaces do not
-                           overlap i.e. at data rates <= 80Mbit/sec.
-
-                           Actually, the idea is close to VJ's one,
-                           only timestamp cache is held not per host,
-                           but per port pair and TW bucket is used
-                           as state holder.
-
-                           If TW bucket has been already destroyed we
-                           fall back to VJ's scheme and use initial
-                           timestamp retrieved from peer table.
-                         */
-                        if (tcptw->tw_ts_recent_stamp &&
-                            (!twp || (sysctl_tcp_tw_reuse &&
-                                      xtime.tv_sec -
-                                      tcptw->tw_ts_recent_stamp > 1))) {
-                                tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
-                                if (tp->write_seq == 0)
-                                        tp->write_seq = 1;
-                                tp->rx_opt.ts_recent       = tcptw->tw_ts_recent;
-                                tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
-                                sock_hold(sk2);
+                        if (twsk_unique(sk, sk2, twp))
                                 goto unique;
-                        } else
+                        else
                                 goto not_unique;
                 }
         }
@@ -869,6 +877,11 @@ struct request_sock_ops tcp_request_sock_ops = {
         .send_reset     =       tcp_v4_send_reset,
 };
 
+static struct timewait_sock_ops tcp_timewait_sock_ops = {
+        .twsk_obj_size  = sizeof(struct tcp_timewait_sock),
+        .twsk_unique    = tcp_twsk_unique,
+};
+
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 {
         struct inet_request_sock *ireq;
@@ -1979,7 +1992,7 @@ struct proto tcp_prot = {
         .sysctl_rmem            = sysctl_tcp_rmem,
         .max_header             = MAX_TCP_HEADER,
         .obj_size               = sizeof(struct tcp_sock),
-        .twsk_obj_size          = sizeof(struct tcp_timewait_sock),
+        .twsk_prot              = &tcp_timewait_sock_ops,
         .rsk_prot               = &tcp_request_sock_ops,
 };