Simplify life for routing table implementations by requiring that rtable_walk

callbacks return EAGAIN if they modify the routing table.  While we're here,
simplify life for rtable_walk callers by moving the loop that restarts the
walk on EAGAIN into rtable_walk itself.

Flushing cloned routes on interface state changes becomes a bit more
inefficient, but this can be improved later.

ok mpi@ dlg@

3 files changed, 23 insertions, 17 deletions

diff --git a/sys/net/if_spppsubr.c b/sys/net/if_spppsubr.c
index 0f32d19ced9..d2ad8c5d80d 100644
--- a/sys/net/if_spppsubr.c
+++ b/sys/net/if_spppsubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_spppsubr.c,v 1.151 2016/05/01 14:08:39 sthen Exp $	*/
+/*	$OpenBSD: if_spppsubr.c,v 1.152 2016/05/02 22:15:49 jmatthew Exp $	*/
 /*
  * Synchronous PPP link level subroutines.
  *
@@ -4171,9 +4171,7 @@ sppp_update_gw(struct ifnet *ifp)
 
 	/* update routing table */
 	for (tid = 0; tid <= RT_TABLEID_MAX; tid++) {
-		while (rtable_walk(tid, AF_INET, sppp_update_gw_walker,
-		    ifp) == EAGAIN)
-			;	/* nothing */
+		rtable_walk(tid, AF_INET, sppp_update_gw_walker, ifp);
 	}
 }
 
diff --git a/sys/net/route.c b/sys/net/route.c
index 3517ef5c679..33f9a42a43b 100644
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: route.c,v 1.299 2016/04/27 14:47:27 mpi Exp $	*/
+/*	$OpenBSD: route.c,v 1.300 2016/05/02 22:15:49 jmatthew Exp $	*/
 /*	$NetBSD: route.c,v 1.14 1996/02/13 22:00:46 christos Exp $	*/
 
 /*
@@ -669,6 +669,7 @@ rtflushclone1(struct rtentry *rt, void *arg, u_int id)
 {
 	struct rtentry *parent = arg;
 	struct ifnet *ifp;
+	int error;
 
 	ifp = if_get(rt->rt_ifidx);
 
@@ -680,11 +681,14 @@ rtflushclone1(struct rtentry *rt, void *arg, u_int id)
 	if (ifp == NULL)
 	        return 0;
 
-	if (ISSET(rt->rt_flags, RTF_CLONED) && rtequal(rt->rt_parent, parent))
+	if (ISSET(rt->rt_flags, RTF_CLONED) && rtequal(rt->rt_parent, parent)) {
 	        rtdeletemsg(rt, ifp, id);
+		error = EAGAIN;
+	} else
+		error = 0;
 
 	if_put(ifp);
-	return 0;
+	return error;
 }
 
 void
@@ -1708,9 +1712,7 @@ rt_if_remove(struct ifnet *ifp)
 		if (rtable_l2(tid) != ifp->if_rdomain)
 			continue;
 		for (i = 1; i <= AF_MAX; i++) {
-			while (rtable_walk(tid, i, rt_if_remove_rtdelete,
-				ifp) == EAGAIN)
-					;	/* nothing */
+			rtable_walk(tid, i, rt_if_remove_rtdelete, ifp);
 		}
 	}
 }
@@ -1751,9 +1753,7 @@ rt_if_track(struct ifnet *ifp)
 			if (!rtable_mpath_capable(tid, i))
 				continue;
 
-			while (rtable_walk(tid, i,
-			    rt_if_linkstate_change, ifp) == EAGAIN)
-				;	/* nothing */
+			rtable_walk(tid, i, rt_if_linkstate_change, ifp);
 		}
 	}
 }
@@ -1790,7 +1790,7 @@ rt_if_linkstate_change(struct rtentry *rt, void *arg, u_int id)
 			 */
 			if (rt->rt_flags & RTF_CLONED) {
 				rtdeletemsg(rt, ifp, id);
-				return (0);
+				return (EAGAIN);
 			}
 			/* take route down */
 			rt->rt_flags &= ~RTF_UP;
diff --git a/sys/net/rtable.c b/sys/net/rtable.c
index 2221a492a23..0a3a09e0111 100644
--- a/sys/net/rtable.c
+++ b/sys/net/rtable.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtable.c,v 1.40 2016/04/13 08:04:14 mpi Exp $ */
+/*	$OpenBSD: rtable.c,v 1.41 2016/05/02 22:15:49 jmatthew Exp $ */
 
 /*
  * Copyright (c) 2014-2015 Martin Pieuchot
@@ -459,12 +459,16 @@ rtable_walk(unsigned int rtableid, sa_family_t af,
 {
 	struct radix_node_head	*rnh;
 	int (*f)(struct radix_node *, void *, unsigned int) = (void *)func;
+	int error;
 
 	rnh = rtable_get(rtableid, af);
 	if (rnh == NULL)
 		return (EAFNOSUPPORT);
 
-	return (rn_walktree(rnh, f, arg));
+	while ((error = rn_walktree(rnh, f, arg)) == EAGAIN)
+		;	/* nothing */
+
+	return (error);
 }
 
 #ifndef SMALL_KERNEL
@@ -846,6 +850,7 @@ rtable_walk(unsigned int rtableid, sa_family_t af,
 {
 	struct art_root			*ar;
 	struct rtable_walk_cookie	 rwc;
+	int				 error;
 
 	ar = rtable_get(rtableid, af);
 	if (ar == NULL)
@@ -855,7 +860,10 @@ rtable_walk(unsigned int rtableid, sa_family_t af,
 	rwc.rwc_arg = arg;
 	rwc.rwc_rid = rtableid;
 
-	return (art_walk(ar, rtable_walk_helper, &rwc));
+	while ((error = art_walk(ar, rtable_walk_helper, &rwc)) == EAGAIN)
+		; /* nothing */
+
+	return (error);
 }
 
 #ifndef SMALL_KERNEL