Introduce tcp_hostcache and remove the tcp specific metrics from

the routing table.  Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.

It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination.  Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.

tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.

It removes significant locking requirements from the tcp stack with
regard to the routing table.

Reviewed by:	sam (mentor), bms
Reviewed by:	-net, -current, core@kame.net (IPv6 parts)
Approved by:	re (scottl)

1 files changed, 8 insertions, 36 deletions

diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
index 5c7f1f2..b3d58e8 100644
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -337,8 +337,7 @@ in6_pcbladdr(inp, nam, plocal_addr6)
 		 * Is it the intended behavior?
 		 */
 		*plocal_addr6 = in6_selectsrc(sin6, inp->in6p_outputopts,
-					      inp->in6p_moptions,
-					      &inp->in6p_route,
+					      inp->in6p_moptions, NULL,
 					      &inp->in6p_laddr, &error);
 		if (*plocal_addr6 == 0) {
 			if (error == 0)
@@ -351,10 +350,6 @@ in6_pcbladdr(inp, nam, plocal_addr6)
 		 * and exit to caller, that will do the lookup.
 		 */
 	}
-
-	if (inp->in6p_route.ro_rt)
-		ifp = inp->in6p_route.ro_rt->rt_ifp;
-
 	return (0);
 }
 
@@ -447,8 +442,6 @@ in6_pcbdetach(inp)
 
  	ip6_freepcbopts(inp->in6p_outputopts);
  	ip6_freemoptions(inp->in6p_moptions);
-	if (inp->in6p_route.ro_rt)
-		RTFREE(inp->in6p_route.ro_rt);
 	/* Check and free IPv4 related resources in case of mapped addr */
 	if (inp->inp_options)
 		(void)m_free(inp->inp_options);
@@ -830,26 +823,10 @@ void
 in6_losing(in6p)
 	struct inpcb *in6p;
 {
-	struct rtentry *rt;
-	struct rt_addrinfo info;
-
-	if ((rt = in6p->in6p_route.ro_rt) != NULL) {
-		RT_LOCK(rt);
-		in6p->in6p_route.ro_rt = NULL;
-		bzero((caddr_t)&info, sizeof(info));
-		info.rti_flags = rt->rt_flags;
-		info.rti_info[RTAX_DST] = rt_key(rt);
-		info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
-		info.rti_info[RTAX_NETMASK] = rt_mask(rt);
-		rt_missmsg(RTM_LOSING, &info, rt->rt_flags, 0);
-		if (rt->rt_flags & RTF_DYNAMIC)
-			rtexpunge(rt);
-		RTFREE_LOCKED(rt);
-		/*
-		 * A new route can be allocated
-		 * the next time output is attempted.
-		 */
-	}
+	/*
+	 * We don't store route pointers in the routing table anymore
+	 */
+	return;
 }
 
 /*
@@ -861,14 +838,9 @@ in6_rtchange(inp, errno)
 	struct inpcb *inp;
 	int errno;
 {
-	if (inp->in6p_route.ro_rt) {
-		RTFREE(inp->in6p_route.ro_rt);
-		inp->in6p_route.ro_rt = 0;
-		/*
-		 * A new route can be allocated the next time
-		 * output is attempted.
-		 */
-	}
+	/*
+	 * We don't store route pointers in the routing table anymore
+	 */
 	return inp;
 }