net: Use VRF device index for lookups on RX

On ingress use index of VRF master device for route lookups if real device
is enslaved. Rules are expected to be installed for the VRF device to
direct lookups to a specific table.
Signed-off-by: Shrijeet Mukherjee <shm@cumulusnetworks.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/fib_frontend.c

@@ -45,6 +45,7 @@
 #include <net/ip_fib.h>
 #include <net/rtnetlink.h>
 #include <net/xfrm.h>
+#include <net/vrf.h>
 
 #ifndef CONFIG_IP_MULTIPLE_TABLES
 
@@ -309,6 +310,8 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	bool dev_match;
 
 	fl4.flowi4_oif = 0;
+	fl4.flowi4_iif = vrf_master_ifindex_rcu(dev);
+	if (!fl4.flowi4_iif)
 		fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
 	fl4.daddr = src;
 	fl4.saddr = dst;
@@ -339,6 +342,9 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 		if (nh->nh_dev == dev) {
 			dev_match = true;
 			break;
+		} else if (vrf_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
+			dev_match = true;
+			break;
 		}
 	}
 #else

net/ipv4/route.c

@@ -112,6 +112,7 @@
 #endif
 #include <net/secure_seq.h>
 #include <net/ip_tunnels.h>
+#include <net/vrf.h>
 
 #define RT_FL_TOS(oldflp4) \
 	((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
@@ -1726,7 +1727,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	 *	Now we are ready to route packet.
 	 */
 	fl4.flowi4_oif = 0;
-	fl4.flowi4_iif = dev->ifindex;
+	fl4.flowi4_iif = vrf_master_ifindex_rcu(dev) ? : dev->ifindex;
 	fl4.flowi4_mark = skb->mark;
 	fl4.flowi4_tos = tos;
 	fl4.flowi4_scope = RT_SCOPE_UNIVERSE;