[TWSK]: Introduce struct timewait_sock_ops

So that we can share several timewait sockets related functions and
make the timewait mini sockets infrastructure closer to the request
mini sockets one.

Next changesets will take advantage of this, moving more code out of
TCP and DCCP v4 and v6 to common infrastructure.

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

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,
 };