ipv4: Prepare rtable for IPv6 gateway

To allow the gateway to be either an IPv4 or IPv6 address, remove
rt_uses_gateway from rtable and replace with rt_gw_family. If
rt_gw_family is set it implies rt_uses_gateway. Rename rt_gateway
to rt_gw4 to represent the IPv4 version.

Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 43 insertions, 36 deletions

diff --git a/net/atm/clip.c b/net/atm/clip.c
index d795b9c5aea4..b9e67e589a7b 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -345,8 +345,8 @@ static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
 		return NETDEV_TX_OK;
 	}
 	rt = (struct rtable *) dst;
-	if (rt->rt_gateway)
-		daddr = &rt->rt_gateway;
+	if (rt->rt_gw_family == AF_INET)
+		daddr = &rt->rt_gw4;
 	else
 		daddr = &ip_hdr(skb)->daddr;
 	n = dst_neigh_lookup(dst, daddr);
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 6ea523d71947..a175e3e7ae97 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -564,7 +564,7 @@ struct dst_entry *inet_csk_route_req(const struct sock *sk,
 	rt = ip_route_output_flow(net, fl4, sk);
 	if (IS_ERR(rt))
 		goto no_route;
-	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
+	if (opt && opt->opt.is_strictroute && rt->rt_gw_family)
 		goto route_err;
 	rcu_read_unlock();
 	return &rt->dst;
@@ -602,7 +602,7 @@ struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 	rt = ip_route_output_flow(net, fl4, sk);
 	if (IS_ERR(rt))
 		goto no_route;
-	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
+	if (opt && opt->opt.is_strictroute && rt->rt_gw_family)
 		goto route_err;
 	return &rt->dst;
 
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
index 00ec819f949b..06f6f280b9ff 100644
--- a/net/ipv4/ip_forward.c
+++ b/net/ipv4/ip_forward.c
@@ -123,7 +123,7 @@ int ip_forward(struct sk_buff *skb)
 
 	rt = skb_rtable(skb);
 
-	if (opt->is_strictroute && rt->rt_uses_gateway)
+	if (opt->is_strictroute && rt->rt_gw_family)
 		goto sr_failed;
 
 	IPCB(skb)->flags |= IPSKB_FORWARDED;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 10b35328cfbc..a2bd4a6d9e6b 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -472,7 +472,7 @@ int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
 	skb_dst_set_noref(skb, &rt->dst);
 
 packet_routed:
-	if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
+	if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_gw_family)
 		goto no_route;
 
 	/* OK, we know where to send it, allocate and build IP header. */
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index e7338e421796..b77b4950d0c7 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -434,14 +434,13 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 					   struct sk_buff *skb,
 					   const void *daddr)
 {
+	const struct rtable *rt = container_of(dst, struct rtable, dst);
 	struct net_device *dev = dst->dev;
 	const __be32 *pkey = daddr;
-	const struct rtable *rt;
 	struct neighbour *n;
 
-	rt = (const struct rtable *) dst;
-	if (rt->rt_gateway)
-		pkey = (const __be32 *) &rt->rt_gateway;
+	if (rt->rt_gw_family == AF_INET)
+		pkey = (const __be32 *) &rt->rt_gw4;
 	else if (skb)
 		pkey = &ip_hdr(skb)->daddr;
 
@@ -453,13 +452,12 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
 
 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 {
+	const struct rtable *rt = container_of(dst, struct rtable, dst);
 	struct net_device *dev = dst->dev;
 	const __be32 *pkey = daddr;
-	const struct rtable *rt;
 
-	rt = (const struct rtable *)dst;
-	if (rt->rt_gateway)
-		pkey = (const __be32 *)&rt->rt_gateway;
+	if (rt->rt_gw_family == AF_INET)
+		pkey = (const __be32 *)&rt->rt_gw4;
 	else if (!daddr ||
 		 (rt->rt_flags &
 		  (RTCF_MULTICAST | RTCF_BROADCAST | RTCF_LOCAL)))
@@ -629,8 +627,8 @@ 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_gateway = fnhe->fnhe_gw;
-		rt->rt_uses_gateway = 1;
+		rt->rt_gw_family = AF_INET;
+		rt->rt_gw4 = fnhe->fnhe_gw;
 	}
 }
 
@@ -747,7 +745,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
 		return;
 	}
 
-	if (rt->rt_gateway != old_gw)
+	if (rt->rt_gw_family != AF_INET || rt->rt_gw4 != old_gw)
 		return;
 
 	in_dev = __in_dev_get_rcu(dev);
@@ -1282,7 +1280,7 @@ 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_uses_gateway && mtu > 576)
+		if (rt->rt_gw_family && mtu > 576)
 			mtu = 576;
 	}
 
@@ -1410,8 +1408,10 @@ static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
 			orig = NULL;
 		}
 		fill_route_from_fnhe(rt, fnhe);
-		if (!rt->rt_gateway)
-			rt->rt_gateway = daddr;
+		if (!rt->rt_gw4) {
+			rt->rt_gw4 = daddr;
+			rt->rt_gw_family = AF_INET;
+		}
 
 		if (do_cache) {
 			dst_hold(&rt->dst);
@@ -1538,8 +1538,8 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 		struct fib_nh *nh = container_of(nhc, struct fib_nh, nh_common);
 
 		if (nh->fib_nh_gw4 && nh->fib_nh_scope == RT_SCOPE_LINK) {
-			rt->rt_gateway = nh->fib_nh_gw4;
-			rt->rt_uses_gateway = 1;
+			rt->rt_gw4 = nh->fib_nh_gw4;
+			rt->rt_gw_family = AF_INET;
 		}
 		ip_dst_init_metrics(&rt->dst, fi->fib_metrics);
 
@@ -1557,8 +1557,10 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 			 * However, if we are unsuccessful at storing this
 			 * route into the cache we really need to set it.
 			 */
-			if (!rt->rt_gateway)
-				rt->rt_gateway = daddr;
+			if (!rt->rt_gw4) {
+				rt->rt_gw_family = AF_INET;
+				rt->rt_gw4 = daddr;
+			}
 			rt_add_uncached_list(rt);
 		}
 	} else
@@ -1591,8 +1593,8 @@ struct rtable *rt_dst_alloc(struct net_device *dev,
 		rt->rt_iif = 0;
 		rt->rt_pmtu = 0;
 		rt->rt_mtu_locked = 0;
-		rt->rt_gateway = 0;
-		rt->rt_uses_gateway = 0;
+		rt->rt_gw_family = 0;
+		rt->rt_gw4 = 0;
 		INIT_LIST_HEAD(&rt->rt_uncached);
 
 		rt->dst.output = ip_output;
@@ -2595,8 +2597,9 @@ 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_gateway = ort->rt_gateway;
-		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;
 
 		INIT_LIST_HEAD(&rt->rt_uncached);
 	}
@@ -2675,8 +2678,8 @@ 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_uses_gateway &&
-	    nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gateway))
+	if (rt->rt_gw_family == AF_INET &&
+	    nla_put_in_addr(skb, RTA_GATEWAY, rt->rt_gw4))
 		goto nla_put_failure;
 
 	expires = rt->dst.expires;
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index d73a6d6652f6..ee53a91526e5 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -97,8 +97,9 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
 					      RTCF_LOCAL);
 	xdst->u.rt.rt_type = rt->rt_type;
-	xdst->u.rt.rt_gateway = rt->rt_gateway;
-	xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
+	xdst->u.rt.rt_gw_family = rt->rt_gw_family;
+	if (rt->rt_gw_family == AF_INET)
+		xdst->u.rt.rt_gw4 = rt->rt_gw4;
 	xdst->u.rt.rt_pmtu = rt->rt_pmtu;
 	xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
 	INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index f3a8557494d6..1f61b4e53686 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -137,10 +137,13 @@ static int mpls_xmit(struct sk_buff *skb)
 
 	mpls_stats_inc_outucastpkts(out_dev, skb);
 
-	if (rt)
-		err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
-				 skb);
-	else if (rt6) {
+	if (rt) {
+		if (rt->rt_gw_family == AF_INET)
+			err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gw4,
+					 skb);
+		else
+			err = -EAFNOSUPPORT;
+	} else if (rt6) {
 		if (ipv6_addr_v4mapped(&rt6->rt6i_gateway)) {
 			/* 6PE (RFC 4798) */
 			err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt6->rt6i_gateway.s6_addr32[3],