ipv4: Make rt->fl.iif tests lest obscure.

When we test rt->fl.iif against zero, we're seeing if it's
an output or an input route.

Make that explicit with some helper functions.

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

5 files changed, 15 insertions, 15 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 96bc7f9..c6e2aff 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -506,8 +506,8 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 		struct net_device *dev = NULL;
 
 		rcu_read_lock();
-		if (rt->fl.iif &&
-			net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
+		if (rt_is_input_route(rt) &&
+		    net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr)
 			dev = dev_get_by_index_rcu(net, rt->fl.iif);
 
 		if (dev)
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index c8877c6..08d0d81 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -961,7 +961,7 @@ int igmp_rcv(struct sk_buff *skb)
 	case IGMP_HOST_MEMBERSHIP_REPORT:
 	case IGMPV2_HOST_MEMBERSHIP_REPORT:
 		/* Is it our report looped back? */
-		if (skb_rtable(skb)->fl.iif == 0)
+		if (rt_is_output_route(skb_rtable(skb)))
 			break;
 		/* don't rely on MC router hearing unicast reports */
 		if (skb->pkt_type == PACKET_MULTICAST ||
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 70ff77f..cab2057 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -634,7 +634,7 @@ static int ipgre_rcv(struct sk_buff *skb)
 #ifdef CONFIG_NET_IPGRE_BROADCAST
 		if (ipv4_is_multicast(iph->daddr)) {
 			/* Looped back packet, drop it! */
-			if (skb_rtable(skb)->fl.iif == 0)
+			if (rt_is_output_route(skb_rtable(skb)))
 				goto drop;
 			tunnel->dev->stats.multicast++;
 			skb->pkt_type = PACKET_BROADCAST;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 86dd569..ef2b008 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1654,7 +1654,7 @@ static int ip_mr_forward(struct net *net, struct mr_table *mrt,
 	if (mrt->vif_table[vif].dev != skb->dev) {
 		int true_vifi;
 
-		if (skb_rtable(skb)->fl.iif == 0) {
+		if (rt_is_output_route(skb_rtable(skb))) {
 			/* It is our own packet, looped back.
 			 * Very complicated situation...
 			 *
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 5955965..66610ea 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -623,7 +623,7 @@ static inline int rt_fast_clean(struct rtable *rth)
 	/* Kill broadcast/multicast entries very aggresively, if they
 	   collide in hash table with more useful entries */
 	return (rth->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) &&
-		rth->fl.iif && rth->dst.rt_next;
+		rt_is_input_route(rth) && rth->dst.rt_next;
 }
 
 static inline int rt_valuable(struct rtable *rth)
@@ -668,7 +668,7 @@ static inline u32 rt_score(struct rtable *rt)
 	if (rt_valuable(rt))
 		score |= (1<<31);
 
-	if (!rt->fl.iif ||
+	if (rt_is_output_route(rt) ||
 	    !(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL)))
 		score |= (1<<30);
 
@@ -1126,7 +1126,7 @@ restart:
 		 */
 
 		rt->dst.flags |= DST_NOCACHE;
-		if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
+		if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
 			int err = arp_bind_neighbour(&rt->dst);
 			if (err) {
 				if (net_ratelimit())
@@ -1224,7 +1224,7 @@ restart:
 	/* Try to bind route to arp only if it is output
 	   route or unicast forwarding path.
 	 */
-	if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
+	if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
 		int err = arp_bind_neighbour(&rt->dst);
 		if (err) {
 			spin_unlock_bh(rt_hash_lock_addr(hash));
@@ -1406,7 +1406,7 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 				if (rth->fl.fl4_dst != daddr ||
 				    rth->fl.fl4_src != skeys[i] ||
 				    rth->fl.oif != ikeys[k] ||
-				    rth->fl.iif != 0 ||
+				    rt_is_input_route(rth) ||
 				    rt_is_expired(rth) ||
 				    !net_eq(dev_net(rth->dst.dev), net)) {
 					rthp = &rth->dst.rt_next;
@@ -1666,7 +1666,7 @@ unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
 				    rth->rt_dst != daddr ||
 				    rth->rt_src != iph->saddr ||
 				    rth->fl.oif != ikeys[k] ||
-				    rth->fl.iif != 0 ||
+				    rt_is_input_route(rth) ||
 				    dst_metric_locked(&rth->dst, RTAX_MTU) ||
 				    !net_eq(dev_net(rth->dst.dev), net) ||
 				    rt_is_expired(rth))
@@ -1770,7 +1770,7 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt)
 	__be32 src;
 	struct fib_result res;
 
-	if (rt->fl.iif == 0)
+	if (rt_is_output_route(rt))
 		src = rt->rt_src;
 	else {
 		rcu_read_lock();
@@ -2669,7 +2669,7 @@ int __ip_route_output_key(struct net *net, struct rtable **rp,
 		rth = rcu_dereference_bh(rth->dst.rt_next)) {
 		if (rth->fl.fl4_dst == flp->fl4_dst &&
 		    rth->fl.fl4_src == flp->fl4_src &&
-		    rth->fl.iif == 0 &&
+		    rt_is_output_route(rth) &&
 		    rth->fl.oif == flp->oif &&
 		    rth->fl.mark == flp->mark &&
 		    !((rth->fl.fl4_tos ^ flp->fl4_tos) &
@@ -2824,7 +2824,7 @@ static int rt_fill_info(struct net *net,
 	if (rt->dst.tclassid)
 		NLA_PUT_U32(skb, RTA_FLOW, rt->dst.tclassid);
 #endif
-	if (rt->fl.iif)
+	if (rt_is_input_route(rt))
 		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_spec_dst);
 	else if (rt->rt_src != rt->fl.fl4_src)
 		NLA_PUT_BE32(skb, RTA_PREFSRC, rt->rt_src);
@@ -2849,7 +2849,7 @@ static int rt_fill_info(struct net *net,
 		}
 	}
 
-	if (rt->fl.iif) {
+	if (rt_is_input_route(rt)) {
 #ifdef CONFIG_IP_MROUTE
 		__be32 dst = rt->rt_dst;