Save some space in struct rib_entry so it is back to 64bytes (on 64bit archs).

Doing this by folding the lock flag into a pointer and providing an accessor
function for the rib pointer. This is an acceptable middle path for this
important structure.
OK benno@ on an earlier version

4 files changed, 48 insertions, 24 deletions

diff --git a/usr.sbin/bgpd/rde.c b/usr.sbin/bgpd/rde.c
index 02762aa8b0c..1c42fe2f557 100644
--- a/usr.sbin/bgpd/rde.c
+++ b/usr.sbin/bgpd/rde.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.c,v 1.358 2017/01/24 04:22:42 benno Exp $ */
+/*	$OpenBSD: rde.c,v 1.359 2017/01/24 23:38:12 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -2870,7 +2870,7 @@ rde_up_dump_upcall(struct rib_entry *re, void *ptr)
 {
 	struct rde_peer		*peer = ptr;
 
-	if (re->rib != &peer->rib->rib)
+	if (re_rib(re) != &peer->rib->rib)
 		fatalx("King Bula: monstrous evil horror.");
 	if (re->active == NULL)
 		return;
diff --git a/usr.sbin/bgpd/rde.h b/usr.sbin/bgpd/rde.h
index 867f6b28370..d2228b6808a 100644
--- a/usr.sbin/bgpd/rde.h
+++ b/usr.sbin/bgpd/rde.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.h,v 1.157 2017/01/23 22:53:52 claudio Exp $ */
+/*	$OpenBSD: rde.h,v 1.158 2017/01/24 23:38:12 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org> and
@@ -22,6 +22,7 @@
 #include <sys/types.h>
 #include <sys/queue.h>
 #include <sys/tree.h>
+#include <stdint.h>
 
 #include "bgpd.h"
 
@@ -280,10 +281,9 @@ struct rib_context {
 struct rib_entry {
 	RB_ENTRY(rib_entry)	 rib_e;
 	struct prefix_head	 prefix_h;
-	struct prefix		*active; /* for fast access */
+	struct prefix		*active;	/* for fast access */
 	struct pt_entry		*prefix;
-	struct rib		*rib;
-	u_int16_t		 flags;
+	struct rib		*__rib;		/* mangled pointer with flags */
 };
 
 struct rib {
@@ -438,6 +438,13 @@ void		 rib_dump_r(struct rib_context *);
 void		 rib_dump_runner(void);
 int		 rib_dump_pending(void);
 
+static inline struct rib *
+re_rib(struct rib_entry *re)
+{
+	return (struct rib *)((intptr_t)re->__rib & ~1);
+}
+
+void		 path_init(u_int32_t);
 void		 path_init(u_int32_t);
 void		 path_shutdown(void);
 int		 path_update(struct rib *, struct rde_peer *,
diff --git a/usr.sbin/bgpd/rde_decide.c b/usr.sbin/bgpd/rde_decide.c
index 5e23b62a560..84d11c55c92 100644
--- a/usr.sbin/bgpd/rde_decide.c
+++ b/usr.sbin/bgpd/rde_decide.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_decide.c,v 1.64 2017/01/24 04:22:42 benno Exp $ */
+/*	$OpenBSD: rde_decide.c,v 1.65 2017/01/24 23:38:12 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -244,7 +244,7 @@ prefix_evaluate(struct prefix *p, struct rib_entry *re)
 {
 	struct prefix	*xp;
 
-	if (re->flags & F_RIB_NOEVALUATE || rde_noevaluate()) {
+	if (re_rib(re)->flags & F_RIB_NOEVALUATE || rde_noevaluate()) {
 		/* decision process is turned off */
 		if (p != NULL)
 			LIST_INSERT_HEAD(&re->prefix_h, p, rib_l);
@@ -288,9 +288,9 @@ prefix_evaluate(struct prefix *p, struct rib_entry *re)
 		 * but remember that xp may be NULL aka ineligible.
 		 * Additional decision may be made by the called functions.
 		 */
-		rde_generate_updates(re->rib->id, xp, re->active);
-		if ((re->flags & F_RIB_NOFIB) == 0)
-			rde_send_kroute(xp, re->active, re->rib->id);
+		rde_generate_updates(re_rib(re)->id, xp, re->active);
+		if ((re_rib(re)->flags & F_RIB_NOFIB) == 0)
+			rde_send_kroute(xp, re->active, re_rib(re)->id);
 
 		re->active = xp;
 		if (xp != NULL)
diff --git a/usr.sbin/bgpd/rde_rib.c b/usr.sbin/bgpd/rde_rib.c
index 7f716a1a2e4..54d3dfde91d 100644
--- a/usr.sbin/bgpd/rde_rib.c
+++ b/usr.sbin/bgpd/rde_rib.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_rib.c,v 1.150 2017/01/24 04:22:42 benno Exp $ */
+/*	$OpenBSD: rde_rib.c,v 1.151 2017/01/24 23:38:12 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -49,6 +49,24 @@ struct rib_entry *rib_restart(struct rib_context *);
 RB_PROTOTYPE(rib_tree, rib_entry, rib_e, rib_compare);
 RB_GENERATE(rib_tree, rib_entry, rib_e, rib_compare);
 
+static inline void
+re_lock(struct rib_entry *re)
+{
+	re->__rib = (struct rib *)((intptr_t)re->__rib | 1);
+}
+
+static inline void
+re_unlock(struct rib_entry *re)
+{
+	re->__rib = (struct rib *)((intptr_t)re->__rib & ~1);
+}
+
+static inline int
+re_is_locked(struct rib_entry *re)
+{
+	return ((intptr_t)re->__rib & 1);
+}
+
 static inline struct rib_tree *
 rib_tree(struct rib *rib)
 {
@@ -121,7 +139,7 @@ rib_free(struct rib_desc *rib)
 		next = LIST_NEXT(ctx, entry);
 		if (ctx->ctx_rib == &rib->rib) {
 			re = ctx->ctx_re;
-			re->flags &= ~F_RIB_ENTRYLOCK;
+			re_unlock(re);
 			LIST_REMOVE(ctx, entry);
 			if (ctx->ctx_done)
 				ctx->ctx_done(ctx->ctx_arg);
@@ -222,8 +240,7 @@ rib_add(struct rib *rib, struct bgpd_addr *prefix, int prefixlen)
 
 	LIST_INIT(&re->prefix_h);
 	re->prefix = pte;
-	re->rib = rib;
-	re->flags = rib->flags;
+	re->__rib = rib;
 
         if (RB_INSERT(rib_tree, rib_tree(rib), re) != NULL) {
 		log_warnx("rib_add: insert failed");
@@ -244,7 +261,7 @@ rib_remove(struct rib_entry *re)
 	if (!rib_empty(re))
 		fatalx("rib_remove: entry not empty");
 
-	if (re->flags & F_RIB_ENTRYLOCK)
+	if (re_is_locked(re))
 		/* entry is locked, don't free it. */
 		return;
 
@@ -252,7 +269,7 @@ rib_remove(struct rib_entry *re)
 	if (pt_empty(re->prefix))
 		pt_remove(re->prefix);
 
-	if (RB_REMOVE(rib_tree, rib_tree(re->rib), re) == NULL)
+	if (RB_REMOVE(rib_tree, rib_tree(re_rib(re)), re) == NULL)
 		log_warnx("rib_remove: remove failed.");
 
 	free(re);
@@ -297,10 +314,10 @@ rib_dump_r(struct rib_context *ctx)
 		    ctx->ctx_aid != re->prefix->aid)
 			continue;
 		if (ctx->ctx_count && i++ >= ctx->ctx_count &&
-		    (re->flags & F_RIB_ENTRYLOCK) == 0) {
+		    re_is_locked(re)) {
 			/* store and lock last element */
 			ctx->ctx_re = re;
-			re->flags |= F_RIB_ENTRYLOCK;
+			re_lock(re);
 			return;
 		}
 		ctx->ctx_upcall(re, ctx->ctx_arg);
@@ -319,7 +336,7 @@ rib_restart(struct rib_context *ctx)
 	struct rib_entry *re;
 
 	re = ctx->ctx_re;
-	re->flags &= ~F_RIB_ENTRYLOCK;
+	re_unlock(re);
 
 	/* find first non empty element */
 	while (re && rib_empty(re))
@@ -548,7 +565,7 @@ path_remove_stale(struct rde_aspath *asp, u_int8_t aid)
 		}
 
 		/* only count Adj-RIB-In */
-		if (p->re->rib == &ribs[0].rib)
+		if (re_rib(p->re) == &ribs[0].rib)
 			rprefixes++;
 
 		prefix_destroy(p);
@@ -905,7 +922,7 @@ prefix_updateall(struct rde_aspath *asp, enum nexthop_state state,
 		/*
 		 * skip non local-RIBs or RIBs that are flagged as noeval.
 		 */
-		if (p->re->rib->flags & F_RIB_NOEVALUATE)
+		if (re_rib(p->re)->flags & F_RIB_NOEVALUATE)
 			continue;
 
 		if (oldstate == state && state == NEXTHOP_REACH) {
@@ -915,9 +932,9 @@ prefix_updateall(struct rde_aspath *asp, enum nexthop_state state,
 			 * or other internal infos. This will not change
 			 * the routing decision so shortcut here.
 			 */
-			if ((p->re->rib->flags & F_RIB_NOFIB) == 0 &&
+			if ((re_rib(p->re)->flags & F_RIB_NOFIB) == 0 &&
 			    p == p->re->active)
-				rde_send_kroute(p, NULL, p->re->rib->id);
+				rde_send_kroute(p, NULL, re_rib(p->re)->id);
 			continue;
 		}