1 files changed, 31 insertions, 22 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 517300d587a7..7dcce724c78b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -635,6 +635,7 @@ static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnh
 
 	if (fnhe->fnhe_gw) {
 		rt->rt_flags |= RTCF_REDIRECTED;
+		rt->rt_uses_gateway = 1;
 		rt->rt_gw_family = AF_INET;
 		rt->rt_gw4 = fnhe->fnhe_gw;
 	}
@@ -1313,7 +1314,7 @@ static unsigned int ipv4_mtu(const struct dst_entry *dst)
 	mtu = READ_ONCE(dst->dev->mtu);
 
 	if (unlikely(ip_mtu_locked(dst))) {
-		if (rt->rt_gw_family && mtu > 576)
+		if (rt->rt_uses_gateway && mtu > 576)
 			mtu = 576;
 	}
 
@@ -1569,6 +1570,7 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 		struct fib_nh_common *nhc = FIB_RES_NHC(*res);
 
 		if (nhc->nhc_gw_family && nhc->nhc_scope == RT_SCOPE_LINK) {
+			rt->rt_uses_gateway = 1;
 			rt->rt_gw_family = nhc->nhc_gw_family;
 			/* only INET and INET6 are supported */
 			if (likely(nhc->nhc_gw_family == AF_INET))
@@ -1634,6 +1636,7 @@ struct rtable *rt_dst_alloc(struct net_device *dev,
 		rt->rt_iif = 0;
 		rt->rt_pmtu = 0;
 		rt->rt_mtu_locked = 0;
+		rt->rt_uses_gateway = 0;
 		rt->rt_gw_family = 0;
 		rt->rt_gw4 = 0;
 		INIT_LIST_HEAD(&rt->rt_uncached);
@@ -2694,6 +2697,7 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
 		rt->rt_genid = rt_genid_ipv4(net);
 		rt->rt_flags = ort->rt_flags;
 		rt->rt_type = ort->rt_type;
+		rt->rt_uses_gateway = ort->rt_uses_gateway;
 		rt->rt_gw_family = ort->rt_gw_family;
 		if (rt->rt_gw_family == AF_INET)
 			rt->rt_gw4 = ort->rt_gw4;
@@ -2728,7 +2732,8 @@ EXPORT_SYMBOL_GPL(ip_route_output_flow);
 /* called with rcu_read_lock held */
 static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
 			struct rtable *rt, u32 table_id, struct flowi4 *fl4,
-			struct sk_buff *skb, u32 portid, u32 seq)
+			struct sk_buff *skb, u32 portid, u32 seq,
+			unsigned int flags)
 {
 	struct rtmsg *r;
 	struct nlmsghdr *nlh;
@@ -2736,7 +2741,7 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
 	u32 error;
 	u32 metrics[RTAX_MAX];
 
-	nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), 0);
+	nlh = nlmsg_put(skb, portid, seq, RTM_NEWROUTE, sizeof(*r), flags);
 	if (!nlh)
 		return -EMSGSIZE;
 
@@ -2777,21 +2782,23 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src,
 		if (nla_put_in_addr(skb, RTA_PREFSRC, fl4->saddr))
 			goto nla_put_failure;
 	}
-	if (rt->rt_gw_family == AF_INET &&
-	    nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
-		goto nla_put_failure;
-	} else if (rt->rt_gw_family == AF_INET6) {
-		int alen = sizeof(struct in6_addr);
-		struct nlattr *nla;
-		struct rtvia *via;
-
-		nla = nla_reserve(skb, RTA_VIA, alen + 2);
-		if (!nla)
+	if (rt->rt_uses_gateway) {
+		if (rt->rt_gw_family == AF_INET &&
+		    nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4)) {
 			goto nla_put_failure;
-
-		via = nla_data(nla);
-		via->rtvia_family = AF_INET6;
-		memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
+		} else if (rt->rt_gw_family == AF_INET6) {
+			int alen = sizeof(struct in6_addr);
+			struct nlattr *nla;
+			struct rtvia *via;
+
+			nla = nla_reserve(skb, RTA_VIA, alen + 2);
+			if (!nla)
+				goto nla_put_failure;
+
+			via = nla_data(nla);
+			via->rtvia_family = AF_INET6;
+			memcpy(via->rtvia_addr, &rt->rt_gw6, alen);
+		}
 	}
 
 	expires = rt->dst.expires;
@@ -2860,7 +2867,7 @@ nla_put_failure:
 static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
 			    struct netlink_callback *cb, u32 table_id,
 			    struct fnhe_hash_bucket *bucket, int genid,
-			    int *fa_index, int fa_start)
+			    int *fa_index, int fa_start, unsigned int flags)
 {
 	int i;
 
@@ -2891,7 +2898,7 @@ static int fnhe_dump_bucket(struct net *net, struct sk_buff *skb,
 			err = rt_fill_info(net, fnhe->fnhe_daddr, 0, rt,
 					   table_id, NULL, skb,
 					   NETLINK_CB(cb->skb).portid,
-					   cb->nlh->nlmsg_seq);
+					   cb->nlh->nlmsg_seq, flags);
 			if (err)
 				return err;
 next:
@@ -2904,7 +2911,7 @@ next:
 
 int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
 		       u32 table_id, struct fib_info *fi,
-		       int *fa_index, int fa_start)
+		       int *fa_index, int fa_start, unsigned int flags)
 {
 	struct net *net = sock_net(cb->skb->sk);
 	int nhsel, genid = fnhe_genid(net);
@@ -2922,7 +2929,8 @@ int fib_dump_info_fnhe(struct sk_buff *skb, struct netlink_callback *cb,
 		err = 0;
 		if (bucket)
 			err = fnhe_dump_bucket(net, skb, cb, table_id, bucket,
-					       genid, fa_index, fa_start);
+					       genid, fa_index, fa_start,
+					       flags);
 		rcu_read_unlock();
 		if (err)
 			return err;
@@ -3183,7 +3191,8 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 				    fl4.flowi4_tos, res.fi, 0);
 	} else {
 		err = rt_fill_info(net, dst, src, rt, table_id, &fl4, skb,
-				   NETLINK_CB(in_skb).portid, nlh->nlmsg_seq);
+				   NETLINK_CB(in_skb).portid,
+				   nlh->nlmsg_seq, 0);
 	}
 	if (err < 0)
 		goto errout_rcu;