Refactor and rename bgpd_filternexthop() to bgpd_oknexthop()

Simplify the logic and adjust kroute_match() which makes the code
easier to understand.
OK tb@

3 files changed, 17 insertions, 23 deletions

diff --git a/usr.sbin/bgpd/bgpd.c b/usr.sbin/bgpd/bgpd.c
index 600e1f89795..2a2b515fdc6 100644
--- a/usr.sbin/bgpd/bgpd.c
+++ b/usr.sbin/bgpd/bgpd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.c,v 1.251 2022/07/22 17:26:58 claudio Exp $ */
+/*	$OpenBSD: bgpd.c,v 1.252 2022/07/23 10:24:00 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -1115,23 +1115,19 @@ send_network(int type, struct network_config *net, struct filter_set_head *h)
 	return (0);
 }
 
+/*
+ * Return true if a route can be used for nexthop resolution.
+ */
 int
-bgpd_filternexthop(struct kroute_full *kf)
+bgpd_oknexthop(struct kroute_full *kf)
 {
-	/* kernel routes are never filtered */
-	if (kf->flags & F_KERNEL && kf->prefixlen != 0)
-		return (0);
+	if (kf->flags & F_BGPD)
+		return ((cflags & BGPD_FLAG_NEXTHOP_BGP) != 0);
 
-	if (cflags & BGPD_FLAG_NEXTHOP_BGP) {
-		if (kf->flags & F_BGPD)
-			return (0);
-	}
-
-	if (cflags & BGPD_FLAG_NEXTHOP_DEFAULT) {
-		if (kf->prefixlen == 0)
-			return (0);
-	}
+	if (kf->prefixlen == 0)
+		return ((cflags & BGPD_FLAG_NEXTHOP_DEFAULT) != 0);
 
+	/* any other route is fine */
 	return (1);
 }
 
diff --git a/usr.sbin/bgpd/bgpd.h b/usr.sbin/bgpd/bgpd.h
index ef75e651206..ce50f2bc7d9 100644
--- a/usr.sbin/bgpd/bgpd.h
+++ b/usr.sbin/bgpd/bgpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.h,v 1.444 2022/07/22 17:26:58 claudio Exp $ */
+/*	$OpenBSD: bgpd.h,v 1.445 2022/07/23 10:24:01 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -1265,7 +1265,7 @@ void		 send_nexthop_update(struct kroute_nexthop *);
 void		 send_imsg_session(int, pid_t, void *, uint16_t);
 int		 send_network(int, struct network_config *,
 		     struct filter_set_head *);
-int		 bgpd_filternexthop(struct kroute_full *);
+int		 bgpd_oknexthop(struct kroute_full *);
 void		 set_pollfd(struct pollfd *, struct imsgbuf *);
 int		 handle_pollfd(struct pollfd *, struct imsgbuf *);
 
diff --git a/usr.sbin/bgpd/kroute.c b/usr.sbin/bgpd/kroute.c
index d261d4220e0..49a73201822 100644
--- a/usr.sbin/bgpd/kroute.c
+++ b/usr.sbin/bgpd/kroute.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kroute.c,v 1.278 2022/07/22 17:26:58 claudio Exp $ */
+/*	$OpenBSD: kroute.c,v 1.279 2022/07/23 10:24:01 claudio Exp $ */
 
 /*
  * Copyright (c) 2022 Claudio Jeker <claudio@openbsd.org>
@@ -2444,7 +2444,7 @@ knexthop_send_update(struct knexthop *kn)
 }
 
 struct kroute *
-kroute_match(struct ktable *kt, struct bgpd_addr *key, int matchall)
+kroute_match(struct ktable *kt, struct bgpd_addr *key, int matchany)
 {
 	int			 i;
 	struct kroute		*kr;
@@ -2453,8 +2453,7 @@ kroute_match(struct ktable *kt, struct bgpd_addr *key, int matchall)
 	for (i = 32; i >= 0; i--) {
 		applymask(&masked, key, i);
 		if ((kr = kroute_find(kt, &masked, i, RTP_ANY)) != NULL)
-			if (matchall ||
-			    bgpd_filternexthop(kr_tofull(kr)) == 0)
+			if (matchany || bgpd_oknexthop(kr_tofull(kr)))
 				return (kr);
 	}
 
@@ -2462,7 +2461,7 @@ kroute_match(struct ktable *kt, struct bgpd_addr *key, int matchall)
 }
 
 struct kroute6 *
-kroute6_match(struct ktable *kt, struct bgpd_addr *key, int matchall)
+kroute6_match(struct ktable *kt, struct bgpd_addr *key, int matchany)
 {
 	int			 i;
 	struct kroute6		*kr6;
@@ -2471,8 +2470,7 @@ kroute6_match(struct ktable *kt, struct bgpd_addr *key, int matchall)
 	for (i = 128; i >= 0; i--) {
 		applymask(&masked, key, i);
 		if ((kr6 = kroute6_find(kt, &masked, i, RTP_ANY)) != NULL)
-			if (matchall ||
-			    bgpd_filternexthop(kr6_tofull(kr6)) == 0)
+			if (matchany || bgpd_oknexthop(kr6_tofull(kr6)))
 				return (kr6);
 	}