Kill custom in_matroute() radix mathing function removing one rte mutex lock.

Initially in_matrote() in_clsroute() in their current state was introduced by
r4105 20 years ago. Instead of deleting inactive routes immediately, we kept them
in route table, setting RTPRF_OURS flag and some expire time. After that, either
GC came or RTPRF_OURS got removed on first-packet. It was a good solution
in that days (and probably another decade after that) to keep TCP metrics.
However, after moving metrics to TCP hostcache in r122922, most of in_rmx
functionality became unused. It might had been used for flushing icmp-originated
routes before rte mutexes/refcounting, but I'm not sure about that.

So it looks like this is nearly impossible to make GC do its work nowadays:

in_rtkill() ignores non-RTPRF_OURS routes.
route can only become RTPRF_OURS after dropping last reference via rtfree()
which calls in_clsroute(), which, it turn, ignores UP and non-RTF_DYNAMIC routes.

Dynamic routes can still be installed via received redirect, but they
have default lifetime (no specific rt_expire) and no one has another trie walker
to call RTFREE() on them.

So, the changelist:
* remove custom rnh_match / rnh_close matching function.
* remove all GC functions
* partially revert r256695 (proto3 is no more used inside kernel,
  it is not possible to use rt_expire from user point of view, proto3 support
  is not complete)
* Finish r241884 (similar to this commit) and remove remaining IPv6 parts

MFC after:	1 month

1 files changed, 0 insertions, 19 deletions

diff --git a/sys/netinet6/in6_rmx.c b/sys/netinet6/in6_rmx.c
index c96db6f..1403647 100644
--- a/sys/netinet6/in6_rmx.c
+++ b/sys/netinet6/in6_rmx.c
@@ -66,7 +66,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
-#include <sys/sysctl.h>
 #include <sys/queue.h>
 #include <sys/socket.h>
 #include <sys/socketvar.h>
@@ -179,24 +178,6 @@ in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
 	return (ret);
 }
 
-SYSCTL_DECL(_net_inet6_ip6);
-
-static VNET_DEFINE(int, rtq_toomany6) = 128;
-	/* 128 cached routes is ``too many'' */
-#define	V_rtq_toomany6			VNET(rtq_toomany6)
-SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache, CTLFLAG_VNET | CTLFLAG_RW,
-    &VNET_NAME(rtq_toomany6) , 0, "");
-
-struct rtqk_arg {
-	struct radix_node_head *rnh;
-	int mode;
-	int updating;
-	int draining;
-	int killed;
-	int found;
-	time_t nextstop;
-};
-
 /*
  * Age old PMTUs.
  */