1 files changed, 71 insertions, 86 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index d1dc6017f5a6..f9132a6de917 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -934,19 +934,19 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 {
 	struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
 				    lockdep_is_held(&rt->fib6_table->tb6_lock));
-	struct fib6_info *iter = NULL;
+	struct fib6_info *iter = NULL, *match = NULL;
 	struct fib6_info __rcu **ins;
-	struct fib6_info __rcu **fallback_ins = NULL;
 	int replace = (info->nlh &&
 		       (info->nlh->nlmsg_flags & NLM_F_REPLACE));
+	int append = (info->nlh &&
+		       (info->nlh->nlmsg_flags & NLM_F_APPEND));
 	int add = (!info->nlh ||
 		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
 	int found = 0;
-	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
 	u16 nlflags = NLM_F_EXCL;
 	int err;
 
-	if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
+	if (append)
 		nlflags |= NLM_F_APPEND;
 
 	ins = &fn->leaf;
@@ -968,13 +968,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 
 			nlflags &= ~NLM_F_EXCL;
 			if (replace) {
-				if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
-					found++;
-					break;
-				}
-				if (rt_can_ecmp)
-					fallback_ins = fallback_ins ?: ins;
-				goto next_iter;
+				found++;
+				break;
 			}
 
 			if (rt6_duplicate_nexthop(iter, rt)) {
@@ -989,86 +984,67 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
 				fib6_metric_set(iter, RTAX_MTU, rt->fib6_pmtu);
 				return -EEXIST;
 			}
-			/* If we have the same destination and the same metric,
-			 * but not the same gateway, then the route we try to
-			 * add is sibling to this route, increment our counter
-			 * of siblings, and later we will add our route to the
-			 * list.
-			 * Only static routes (which don't have flag
-			 * RTF_EXPIRES) are used for ECMPv6.
-			 *
-			 * To avoid long list, we only had siblings if the
-			 * route have a gateway.
-			 */
-			if (rt_can_ecmp &&
-			    rt6_qualify_for_ecmp(iter))
-				rt->fib6_nsiblings++;
+
+			/* first route that matches */
+			if (!match)
+				match = iter;
 		}
 
 		if (iter->fib6_metric > rt->fib6_metric)
 			break;
 
-next_iter:
 		ins = &iter->fib6_next;
 	}
 
-	if (fallback_ins && !found) {
-		/* No ECMP-able route found, replace first non-ECMP one */
-		ins = fallback_ins;
-		iter = rcu_dereference_protected(*ins,
-				    lockdep_is_held(&rt->fib6_table->tb6_lock));
-		found++;
-	}
-
 	/* Reset round-robin state, if necessary */
 	if (ins == &fn->leaf)
 		fn->rr_ptr = NULL;
 
 	/* Link this route to others same route. */
-	if (rt->fib6_nsiblings) {
-		unsigned int fib6_nsiblings;
+	if (append && match) {
 		struct fib6_info *sibling, *temp_sibling;
 
-		/* Find the first route that have the same metric */
-		sibling = leaf;
-		while (sibling) {
-			if (sibling->fib6_metric == rt->fib6_metric &&
-			    rt6_qualify_for_ecmp(sibling)) {
-				list_add_tail(&rt->fib6_siblings,
-					      &sibling->fib6_siblings);
-				break;
-			}
-			sibling = rcu_dereference_protected(sibling->fib6_next,
-				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+		if (rt->fib6_flags & RTF_REJECT) {
+			NL_SET_ERR_MSG(extack,
+				       "Can not append a REJECT route");
+			return -EINVAL;
+		} else if (match->fib6_flags & RTF_REJECT) {
+			NL_SET_ERR_MSG(extack,
+				       "Can not append to a REJECT route");
+			return -EINVAL;
 		}
+		rt->fib6_nsiblings = match->fib6_nsiblings;
+		list_add_tail(&rt->fib6_siblings, &match->fib6_siblings);
+		match->fib6_nsiblings++;
+
 		/* For each sibling in the list, increment the counter of
 		 * siblings. BUG() if counters does not match, list of siblings
 		 * is broken!
 		 */
-		fib6_nsiblings = 0;
 		list_for_each_entry_safe(sibling, temp_sibling,
-					 &rt->fib6_siblings, fib6_siblings) {
+					 &match->fib6_siblings, fib6_siblings) {
 			sibling->fib6_nsiblings++;
-			BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
-			fib6_nsiblings++;
+			BUG_ON(sibling->fib6_nsiblings != match->fib6_nsiblings);
 		}
-		BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
-		rt6_multipath_rebalance(temp_sibling);
+
+		rt6_multipath_rebalance(match);
 	}
 
 	/*
 	 *	insert node
 	 */
 	if (!replace) {
+		enum fib_event_type event;
+
 		if (!add)
 			pr_warn("NLM_F_CREATE should be set when creating new route\n");
 
 add:
 		nlflags |= NLM_F_CREATE;
 
-		err = call_fib6_entry_notifiers(info->nl_net,
-						FIB_EVENT_ENTRY_ADD,
-						rt, extack);
+		event = append ? FIB_EVENT_ENTRY_APPEND : FIB_EVENT_ENTRY_ADD;
+		err = call_fib6_entry_notifiers(info->nl_net, event, rt,
+						extack);
 		if (err)
 			return err;
 
@@ -1086,7 +1062,7 @@ add:
 		}
 
 	} else {
-		int nsiblings;
+		struct fib6_info *tmp;
 
 		if (!found) {
 			if (add)
@@ -1101,48 +1077,57 @@ add:
 		if (err)
 			return err;
 
+		/* if route being replaced has siblings, set tmp to
+		 * last one, otherwise tmp is current route. this is
+		 * used to set fib6_next for new route
+		 */
+		if (iter->fib6_nsiblings)
+			tmp = list_last_entry(&iter->fib6_siblings,
+					      struct fib6_info,
+					      fib6_siblings);
+		else
+			tmp = iter;
+
+		/* insert new route */
 		atomic_inc(&rt->fib6_ref);
 		rcu_assign_pointer(rt->fib6_node, fn);
-		rt->fib6_next = iter->fib6_next;
+		rt->fib6_next = tmp->fib6_next;
 		rcu_assign_pointer(*ins, rt);
+
 		if (!info->skip_notify)
 			inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
 		if (!(fn->fn_flags & RTN_RTINFO)) {
 			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
 			fn->fn_flags |= RTN_RTINFO;
 		}
-		nsiblings = iter->fib6_nsiblings;
-		iter->fib6_node = NULL;
-		fib6_purge_rt(iter, fn, info->nl_net);
-		if (rcu_access_pointer(fn->rr_ptr) == iter)
-			fn->rr_ptr = NULL;
-		fib6_info_release(iter);
 
-		if (nsiblings) {
+		/* delete old route */
+		rt = iter;
+
+		if (rt->fib6_nsiblings) {
+			struct fib6_info *tmp;
+
 			/* Replacing an ECMP route, remove all siblings */
-			ins = &rt->fib6_next;
-			iter = rcu_dereference_protected(*ins,
-				    lockdep_is_held(&rt->fib6_table->tb6_lock));
-			while (iter) {
-				if (iter->fib6_metric > rt->fib6_metric)
-					break;
-				if (rt6_qualify_for_ecmp(iter)) {
-					*ins = iter->fib6_next;
-					iter->fib6_node = NULL;
-					fib6_purge_rt(iter, fn, info->nl_net);
-					if (rcu_access_pointer(fn->rr_ptr) == iter)
-						fn->rr_ptr = NULL;
-					fib6_info_release(iter);
-					nsiblings--;
-					info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
-				} else {
-					ins = &iter->fib6_next;
-				}
-				iter = rcu_dereference_protected(*ins,
-					lockdep_is_held(&rt->fib6_table->tb6_lock));
+			list_for_each_entry_safe(iter, tmp, &rt->fib6_siblings,
+						 fib6_siblings) {
+				iter->fib6_node = NULL;
+				fib6_purge_rt(iter, fn, info->nl_net);
+				if (rcu_access_pointer(fn->rr_ptr) == iter)
+					fn->rr_ptr = NULL;
+				fib6_info_release(iter);
+
+				rt->fib6_nsiblings--;
+				info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
 			}
-			WARN_ON(nsiblings != 0);
 		}
+
+		WARN_ON(rt->fib6_nsiblings != 0);
+
+		rt->fib6_node = NULL;
+		fib6_purge_rt(rt, fn, info->nl_net);
+		if (rcu_access_pointer(fn->rr_ptr) == rt)
+			fn->rr_ptr = NULL;
+		fib6_info_release(rt);
 	}
 
 	return 0;