timewait_sock: Create and use getpeer op.

The only thing AF-specific about remembering the timestamp
for a time-wait TCP socket is getting the peer.

Abstract that behind a new timewait_sock_ops vector.

Support for real IPV6 sockets is not filled in yet, but
curiously this makes timewait recycling start to work
for v4-mapped ipv6 sockets.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 8 deletions

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 059082c873cf..3527b51d6159 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -78,6 +78,27 @@ static int tcp_remember_stamp(struct sock *sk)
         return 0;
 }
 
+static int tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
+{
+        struct sock *sk = (struct sock *) tw;
+        struct inet_peer *peer;
+
+        peer = twsk_getpeer(sk);
+        if (peer) {
+                const struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+
+                if ((s32)(peer->tcp_ts - tcptw->tw_ts_recent) <= 0 ||
+                    ((u32)get_seconds() - peer->tcp_ts_stamp > TCP_PAWS_MSL &&
+                     peer->tcp_ts_stamp <= (u32)tcptw->tw_ts_recent_stamp)) {
+                        peer->tcp_ts_stamp = (u32)tcptw->tw_ts_recent_stamp;
+                        peer->tcp_ts       = tcptw->tw_ts_recent;
+                }
+                inet_putpeer(peer);
+                return 1;
+        }
+        return 0;
+}
+
 static __inline__ int tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win)
 {
         if (seq == s_win)
@@ -178,14 +199,9 @@ kill_with_rst:
                         tcptw->tw_ts_recent       = tmp_opt.rcv_tsval;
                 }
 
-                /* I am shamed, but failed to make it more elegant.
-                 * Yes, it is direct reference to IP, which is impossible
-                 * to generalize to IPv6. Taking into account that IPv6
-                 * do not understand recycling in any case, it not
-                 * a big problem in practice. --ANK */
-                if (tw->tw_family == AF_INET &&
-                    tcp_death_row.sysctl_tw_recycle && tcptw->tw_ts_recent_stamp &&
-                    tcp_v4_tw_remember_stamp(tw))
+                if (tcp_death_row.sysctl_tw_recycle &&
+                    tcptw->tw_ts_recent_stamp &&
+                    tcp_tw_remember_stamp(tw))
                         inet_twsk_schedule(tw, &tcp_death_row, tw->tw_timeout,
                                            TCP_TIMEWAIT_LEN);
                 else