From: Alexander Bluhm <alexander.bluhm@gmx.net>
Subject: route cache counter
To: tech@openbsd.org
Date: Mon, 5 Feb 2024 20:33:40 +0100

Hi,

I would like to improve route caching.  For that netstat counter
are useful.  IPv6 cache is still missing, but add counters for both.

ip6s_forward_cache is obsolete and can be reused for route cache.
Reorder ip6s_wrongif to keep consistent output.

ok?

bluhm

Index: sys/net/route.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/route.c,v
diff -u -p -r1.427 route.c
--- sys/net/route.c	31 Jan 2024 14:56:42 -0000	1.427
+++ sys/net/route.c	5 Feb 2024 16:09:20 -0000
@@ -214,9 +214,11 @@ route_cache(struct route *ro, struct in_
 	    ro->ro_tableid == rtableid &&
 	    ro->ro_dst.sa_family == AF_INET &&
 	    satosin(&ro->ro_dst)->sin_addr.s_addr == addr.s_addr) {
+		ipstat_inc(ips_rtcachehit);
 		return;
 	}
 
+	ipstat_inc(ips_rtcachemiss);
 	rtfree(ro->ro_rt);
 	ro->ro_rt = NULL;
 	ro->ro_generation = gen;
Index: sys/netinet/ip_var.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/ip_var.h,v
diff -u -p -r1.111 ip_var.h
--- sys/netinet/ip_var.h	3 Feb 2024 22:50:09 -0000	1.111
+++ sys/netinet/ip_var.h	5 Feb 2024 16:09:20 -0000
@@ -87,6 +87,8 @@ struct	ipstat {
 	u_long	ips_inswcsum;		/* software checksummed on input */
 	u_long	ips_outswcsum;		/* software checksummed on output */
 	u_long	ips_notmember;		/* multicasts for unregistered groups */
+	u_long	ips_rtcachehit;		/* valid route found in cache */
+	u_long	ips_rtcachemiss;	/* route cache with new destination */
 	u_long	ips_wrongif;		/* packet received on wrong interface */
 	u_long	ips_idropped;		/* lost input due to nobufs, etc. */
 };
@@ -133,6 +135,8 @@ enum ipstat_counters {
 	ips_inswcsum,		/* software checksummed on input */
 	ips_outswcsum,		/* software checksummed on output */
 	ips_notmember,		/* multicasts for unregistered groups */
+	ips_rtcachehit,		/* valid route to destination found in cache */
+	ips_rtcachemiss,	/* route cache filled with new destination */
 	ips_wrongif,		/* packet received on wrong interface */
 	ips_idropped,		/* lost input packets due to nobufs, etc. */
 
Index: sys/netinet6/ip6_var.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet6/ip6_var.h,v
diff -u -p -r1.110 ip6_var.h
--- sys/netinet6/ip6_var.h	3 Feb 2024 22:50:09 -0000	1.110
+++ sys/netinet6/ip6_var.h	5 Feb 2024 16:09:20 -0000
@@ -196,8 +196,8 @@ struct	ip6stat {
 	/* number of times that an deprecated address is chosen */
 	u_int64_t ip6s_sources_deprecated[16];
 
-	u_int64_t ip6s_forward_cachehit;
-	u_int64_t ip6s_forward_cachemiss;
+	u_int64_t ip6s_rtcachehit;	/* valid route found in cache */
+	u_int64_t ip6s_rtcachemiss;	/* route cache with new destination */
 	u_int64_t ip6s_wrongif;		/* packet received on wrong interface */
 	u_int64_t ip6s_idropped;	/* lost input due to nobufs, etc. */
 };
@@ -243,8 +243,8 @@ enum ip6stat_counters {
 	ip6s_sources_samescope = ip6s_sources_otherif + 16,
 	ip6s_sources_otherscope = ip6s_sources_samescope + 16,
 	ip6s_sources_deprecated = ip6s_sources_otherscope + 16,
-	ip6s_forward_cachehit = ip6s_sources_deprecated + 16,
-	ip6s_forward_cachemiss,
+	ip6s_rtcachehit = ip6s_sources_deprecated + 16,
+	ip6s_rtcachemiss,
 	ip6s_wrongif,
 	ip6s_idropped,
 
Index: usr.bin/netstat/inet.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/usr.bin/netstat/inet.c,v
diff -u -p -r1.179 inet.c
--- usr.bin/netstat/inet.c	4 Sep 2023 23:00:36 -0000	1.179
+++ usr.bin/netstat/inet.c	5 Feb 2024 16:19:11 -0000
@@ -621,6 +621,8 @@ ip_stats(char *name)
 	p(ips_inswcsum, "\t%lu input datagram%s software-checksummed\n");
 	p(ips_outswcsum, "\t%lu output datagram%s software-checksummed\n");
 	p(ips_notmember, "\t%lu multicast packet%s which we don't join\n");
+	p1(ips_rtcachehit, "\t%lu route cache hit\n");
+	p1(ips_rtcachemiss, "\t%lu route cache miss\n");
 	p(ips_wrongif, "\t%lu packet%s received on wrong interface\n");
 	p(ips_idropped, "\t%lu input packet%s dropped due to no bufs, etc.\n");
 #undef p
Index: usr.bin/netstat/inet6.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/usr.bin/netstat/inet6.c,v
diff -u -p -r1.56 inet6.c
--- usr.bin/netstat/inet6.c	12 Aug 2022 14:49:15 -0000	1.56
+++ usr.bin/netstat/inet6.c	5 Feb 2024 16:02:17 -0000
@@ -371,7 +371,6 @@ ip6_stats(char *name)
 	p(ip6s_cantfrag, "\t%llu datagram%s that can't be fragmented\n");
 	p(ip6s_badscope, "\t%llu packet%s that violated scope rules\n");
 	p(ip6s_notmember, "\t%llu multicast packet%s which we don't join\n");
-	p(ip6s_wrongif, "\t%llu packet%s received on wrong interface\n");
 	for (first = 1, i = 0; i < 256; i++)
 		if (ip6stat.ip6s_nxthist[i] != 0) {
 			if (first) {
@@ -478,9 +477,9 @@ ip6_stats(char *name)
 			PRINT_SCOPESTAT(ip6s_sources_deprecated[i], i);
 		}
 	}
-
-	p1(ip6s_forward_cachehit, "\t%llu forward cache hit\n");
-	p1(ip6s_forward_cachemiss, "\t%llu forward cache miss\n");
+	p1(ip6s_rtcachehit, "\t%llu route cache hit\n");
+	p1(ip6s_rtcachemiss, "\t%llu route cache miss\n");
+	p(ip6s_wrongif, "\t%llu packet%s received on wrong interface\n");
 	p(ip6s_idropped,
 	    "\t%llu input packet%s dropped due to no bufs, etc.\n");
 #undef p