Merge branch 'newroute-creation-flags'

Guillaume Nault says:

====================
ip: fix creation flags reported in RTM_NEWROUTE events

Netlink messages sent to user-space upon RTM_NEWROUTE events have their
nlmsg_flags field inconsistently set. While the NLM_F_REPLACE and
NLM_F_APPEND bits are correctly handled, NLM_F_CREATE and NLM_F_EXCL
are always 0.

This series sets the NLM_F_CREATE and NLM_F_EXCL bits when applicable,
for IPv4 and IPv6.

Since IPv6 ignores the NLM_F_APPEND flags in requests, this flag isn't
reported in RTM_NEWROUTE IPv6 events. This keeps IPv6 internal
consistency (same flag semantic for user requests and kernel events) at
the cost of bringing different flag interpretation for IPv4 and IPv6.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_trie.c

@@ -1081,7 +1081,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct fib_alias *fa, *new_fa;
 	struct key_vector *l, *tp;
-	unsigned int nlflags = 0;
+	u16 nlflags = NLM_F_EXCL;
 	struct fib_info *fi;
 	u8 plen = cfg->fc_dst_len;
 	u8 slen = KEYLENGTH - plen;
@@ -1126,6 +1126,8 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 		if (cfg->fc_nlflags & NLM_F_EXCL)
 			goto out;
 
+		nlflags &= ~NLM_F_EXCL;
+
 		/* We have 2 goals:
 		 * 1. Find exact match for type, scope, fib_info to avoid
 		 * duplicate routes
@@ -1151,6 +1153,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 			struct fib_info *fi_drop;
 			u8 state;
 
+			nlflags |= NLM_F_REPLACE;
 			fa = fa_first;
 			if (fa_match) {
 				if (fa == fa_match)
@@ -1191,7 +1194,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 			if (state & FA_S_ACCESSED)
 				rt_cache_flush(cfg->fc_nlinfo.nl_net);
 			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
-				tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);
+				tb->tb_id, &cfg->fc_nlinfo, nlflags);
 
 			goto succeeded;
 		}
@@ -1203,7 +1206,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 			goto out;
 
 		if (cfg->fc_nlflags & NLM_F_APPEND)
-			nlflags = NLM_F_APPEND;
+			nlflags |= NLM_F_APPEND;
 		else
 			fa = fa_first;
 	}
@@ -1211,6 +1214,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 	if (!(cfg->fc_nlflags & NLM_F_CREATE))
 		goto out;
 
+	nlflags |= NLM_F_CREATE;
 	err = -ENOBUFS;
 	new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
 	if (!new_fa)

net/ipv6/ip6_fib.c

@@ -743,6 +743,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 		   (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;
 
 	ins = &fn->leaf;
@@ -759,6 +760,8 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
 			if (info->nlh &&
 			    (info->nlh->nlmsg_flags & NLM_F_EXCL))
 				return -EEXIST;
+
+			nlflags &= ~NLM_F_EXCL;
 			if (replace) {
 				if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
 					found++;
@@ -856,6 +859,7 @@ next_iter:
 			pr_warn("NLM_F_CREATE should be set when creating new route\n");
 
 add:
+		nlflags |= NLM_F_CREATE;
 		err = fib6_commit_metrics(&rt->dst, mxc);
 		if (err)
 			return err;
@@ -864,7 +868,7 @@ add:
 		*ins = rt;
 		rt->rt6i_node = fn;
 		atomic_inc(&rt->rt6i_ref);
-		inet6_rt_notify(RTM_NEWROUTE, rt, info, 0);
+		inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
 		info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
 
 		if (!(fn->fn_flags & RTN_RTINFO)) {