Prepare the ground for allowing temporary aspath object living on the stack.

To do this path_copy() gets a second argument (dst, src) and a new function
path_prep() is introduced to initialize an aspath object. The current
path_copy() usage is replaced with path_copy(path_get(), asp) which does
the same. Additionally some const where added to the *_copy functions to
make it more obvious which is the source and target. Also the pftable_ref()
and rtlabel_ref() functions return now the id instead of void.
OK sthen@

6 files changed, 62 insertions, 56 deletions

diff --git a/usr.sbin/bgpd/bgpd.h b/usr.sbin/bgpd/bgpd.h
index 17108cbe0f4..01eee6b7498 100644
--- a/usr.sbin/bgpd/bgpd.h
+++ b/usr.sbin/bgpd/bgpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.h,v 1.319 2018/06/25 14:28:33 claudio Exp $ */
+/*	$OpenBSD: bgpd.h,v 1.320 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -1110,11 +1110,11 @@ void		 rib_ref(u_int16_t);
 u_int16_t	 rtlabel_name2id(const char *);
 const char	*rtlabel_id2name(u_int16_t);
 void		 rtlabel_unref(u_int16_t);
-void		 rtlabel_ref(u_int16_t);
+u_int16_t	 rtlabel_ref(u_int16_t);
 u_int16_t	 pftable_name2id(const char *);
 const char	*pftable_id2name(u_int16_t);
 void		 pftable_unref(u_int16_t);
-void		 pftable_ref(u_int16_t);
+u_int16_t	 pftable_ref(u_int16_t);
 
 /* parse.y */
 int		 cmdline_symset(char *);
diff --git a/usr.sbin/bgpd/name2id.c b/usr.sbin/bgpd/name2id.c
index 2af133278f9..a8c77e04287 100644
--- a/usr.sbin/bgpd/name2id.c
+++ b/usr.sbin/bgpd/name2id.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: name2id.c,v 1.9 2009/06/04 04:46:42 claudio Exp $ */
+/*	$OpenBSD: name2id.c,v 1.10 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2004, 2005 Henning Brauer <henning@openbsd.org>
@@ -41,7 +41,7 @@ TAILQ_HEAD(n2id_labels, n2id_label);
 u_int16_t	 _name2id(struct n2id_labels *, const char *);
 const char	*_id2name(struct n2id_labels *, u_int16_t);
 void		 _unref(struct n2id_labels *, u_int16_t);
-void		 _ref(struct n2id_labels *, u_int16_t);
+u_int16_t	 _ref(struct n2id_labels *, u_int16_t);
 
 struct n2id_labels	rt_labels = TAILQ_HEAD_INITIALIZER(rt_labels);
 struct n2id_labels	pftable_labels = TAILQ_HEAD_INITIALIZER(pftable_labels);
@@ -64,10 +64,10 @@ rtlabel_unref(u_int16_t id)
 	_unref(&rt_labels, id);
 }
 
-void
+u_int16_t
 rtlabel_ref(u_int16_t id)
 {
-	_ref(&rt_labels, id);
+	return (_ref(&rt_labels, id));
 }
 
 u_int16_t
@@ -88,10 +88,10 @@ pftable_unref(u_int16_t id)
 	_unref(&pftable_labels, id);
 }
 
-void
+u_int16_t
 pftable_ref(u_int16_t id)
 {
-	_ref(&pftable_labels, id);
+	return (_ref(&pftable_labels, id));
 }
 
 u_int16_t
@@ -180,17 +180,20 @@ _unref(struct n2id_labels *head, u_int16_t id)
 	}
 }
 
-void
+u_int16_t
 _ref(struct n2id_labels *head, u_int16_t id)
 {
 	struct n2id_label	*label;
 
 	if (id == 0)
-		return;
+		return (0);
 
 	TAILQ_FOREACH(label, head, entry)
 		if (label->id == id) {
 			++label->ref;
-			break;
+			return (id);
 		}
+
+	/* id not found, treat like no id  */
+	return (0);
 }
diff --git a/usr.sbin/bgpd/rde.h b/usr.sbin/bgpd/rde.h
index ac8ad3553f7..4e79c174289 100644
--- a/usr.sbin/bgpd/rde.h
+++ b/usr.sbin/bgpd/rde.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.h,v 1.174 2018/06/28 09:54:48 claudio Exp $ */
+/*	$OpenBSD: rde.h,v 1.175 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org> and
@@ -351,7 +351,7 @@ void		 attr_shutdown(void);
 int		 attr_optadd(struct rde_aspath *, u_int8_t, u_int8_t,
 		     void *, u_int16_t);
 struct attr	*attr_optget(const struct rde_aspath *, u_int8_t);
-void		 attr_copy(struct rde_aspath *, struct rde_aspath *);
+void		 attr_copy(struct rde_aspath *, const struct rde_aspath *);
 int		 attr_compare(struct rde_aspath *, struct rde_aspath *);
 void		 attr_freeall(struct rde_aspath *);
 void		 attr_free(struct rde_aspath *, struct attr *);
@@ -473,7 +473,8 @@ void		 path_remove(struct rde_aspath *);
 u_int32_t	 path_remove_stale(struct rde_aspath *, u_int8_t);
 void		 path_destroy(struct rde_aspath *);
 int		 path_empty(struct rde_aspath *);
-struct rde_aspath *path_copy(struct rde_aspath *);
+struct rde_aspath *path_copy(struct rde_aspath *, const struct rde_aspath *);
+struct rde_aspath *path_prep(struct rde_aspath *);
 struct rde_aspath *path_get(void);
 void		 path_put(struct rde_aspath *);
 
diff --git a/usr.sbin/bgpd/rde_attr.c b/usr.sbin/bgpd/rde_attr.c
index f18e2d559a8..424aac1d8a4 100644
--- a/usr.sbin/bgpd/rde_attr.c
+++ b/usr.sbin/bgpd/rde_attr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_attr.c,v 1.101 2018/04/02 19:25:33 claudio Exp $ */
+/*	$OpenBSD: rde_attr.c,v 1.102 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -209,7 +209,7 @@ attr_optget(const struct rde_aspath *asp, u_int8_t type)
 }
 
 void
-attr_copy(struct rde_aspath *t, struct rde_aspath *s)
+attr_copy(struct rde_aspath *t, const struct rde_aspath *s)
 {
 	u_int8_t	l;
 
diff --git a/usr.sbin/bgpd/rde_filter.c b/usr.sbin/bgpd/rde_filter.c
index c7675bda4ed..9ce19c08ae0 100644
--- a/usr.sbin/bgpd/rde_filter.c
+++ b/usr.sbin/bgpd/rde_filter.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_filter.c,v 1.93 2018/06/28 09:54:48 claudio Exp $ */
+/*	$OpenBSD: rde_filter.c,v 1.94 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -305,8 +305,7 @@ rde_apply_set(struct filter_set_head *sh, struct rde_aspath *asp,
 			/* FALLTHROUGH */
 		case ACTION_PFTABLE_ID:
 			pftable_unref(asp->pftableid);
-			asp->pftableid = set->action.id;
-			pftable_ref(asp->pftableid);
+			asp->pftableid = pftable_ref(set->action.id);
 			break;
 		case ACTION_RTLABEL:
 			/* convert the route label to an id for faster access */
@@ -315,8 +314,7 @@ rde_apply_set(struct filter_set_head *sh, struct rde_aspath *asp,
 			/* FALLTHROUGH */
 		case ACTION_RTLABEL_ID:
 			rtlabel_unref(asp->rtlabelid);
-			asp->rtlabelid = set->action.id;
-			rtlabel_ref(asp->rtlabelid);
+			asp->rtlabelid = rtlabel_ref(set->action.id);
 			break;
 		case ACTION_SET_ORIGIN:
 			asp->origin = set->action.origin;
@@ -1023,7 +1021,7 @@ rde_filter(struct filter_head *rules, struct rde_peer *peer,
 			if (asp != NULL && new != NULL) {
 				/* asp may get modified so create a copy */
 				if (*new == NULL) {
-					*new = path_copy(asp);
+					*new = path_copy(path_get(), asp);
 					/* ... and use the copy from now on */
 					asp = *new;
 				}
diff --git a/usr.sbin/bgpd/rde_rib.c b/usr.sbin/bgpd/rde_rib.c
index 6ba15e94998..94cb6287c34 100644
--- a/usr.sbin/bgpd/rde_rib.c
+++ b/usr.sbin/bgpd/rde_rib.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_rib.c,v 1.164 2018/06/28 08:55:56 claudio Exp $ */
+/*	$OpenBSD: rde_rib.c,v 1.165 2018/06/29 11:45:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -420,7 +420,7 @@ path_update(struct rib *rib, struct rde_peer *peer, struct rde_aspath *nasp,
 	 */
 	if ((asp = path_lookup(nasp, peer)) == NULL) {
 		/* Path not available, create and link a new one. */
-		asp = path_copy(nasp);
+		asp = path_copy(path_get(), nasp);
 		path_link(asp, peer);
 	}
 
@@ -638,46 +638,36 @@ path_link(struct rde_aspath *asp, struct rde_peer *peer)
 }
 
 /*
- * copy asp to a new UNLINKED one mainly for filtering
+ * Copy asp to a new UNLINKED aspath.
+ * On dst either path_get() or path_prep() had to be called before.
  */
 struct rde_aspath *
-path_copy(struct rde_aspath *asp)
+path_copy(struct rde_aspath *dst, const struct rde_aspath *src)
 {
-	struct rde_aspath *nasp;
-
-	nasp = path_get();
-	nasp->aspath = asp->aspath;
-	if (nasp->aspath != NULL) {
-		nasp->aspath->refcnt++;
+	dst->aspath = src->aspath;
+	if (dst->aspath != NULL) {
+		dst->aspath->refcnt++;
 		rdemem.aspath_refs++;
 	}
-	nasp->nexthop = nexthop_ref(asp->nexthop);
-	nasp->med = asp->med;
-	nasp->lpref = asp->lpref;
-	nasp->weight = asp->weight;
-	nasp->origin = asp->origin;
-	nasp->rtlabelid = asp->rtlabelid;
-	rtlabel_ref(nasp->rtlabelid);
-	nasp->pftableid = asp->pftableid;
-	pftable_ref(nasp->pftableid);
-
-	nasp->flags = asp->flags & ~(F_ATTR_LINKED | F_ATTR_UPDATE);
-	attr_copy(nasp, asp);
-
-	return (nasp);
+	dst->nexthop = nexthop_ref(src->nexthop);
+	dst->med = src->med;
+	dst->lpref = src->lpref;
+	dst->weight = src->weight;
+	dst->origin = src->origin;
+	dst->rtlabelid = rtlabel_ref(src->rtlabelid);
+	dst->pftableid = pftable_ref(src->pftableid);
+
+	dst->flags = src->flags & ~(F_ATTR_LINKED | F_ATTR_UPDATE);
+	attr_copy(dst, src);
+
+	return (dst);
 }
 
-/* alloc and initialize new entry. May not fail. */
+/* initialize or pepare an aspath for use */
 struct rde_aspath *
-path_get(void)
+path_prep(struct rde_aspath *asp)
 {
-	struct rde_aspath *asp;
-
-	asp = calloc(1, sizeof(*asp));
-	if (asp == NULL)
-		fatal("path_alloc");
-	rdemem.path_cnt++;
-
+	memset(asp, 0, sizeof(*asp));
 	TAILQ_INIT(&asp->prefixes);
 	TAILQ_INIT(&asp->updates);
 	asp->origin = ORIGIN_INCOMPLETE;
@@ -689,6 +679,20 @@ path_get(void)
 	return (asp);
 }
 
+/* alloc and initialize new entry. May not fail. */
+struct rde_aspath *
+path_get(void)
+{
+	struct rde_aspath *asp;
+
+	asp = malloc(sizeof(*asp));
+	if (asp == NULL)
+		fatal("path_get");
+	rdemem.path_cnt++;
+
+	return (path_prep(asp));
+}
+
 /* free an unlinked element */
 void
 path_put(struct rde_aspath *asp)