net: Fix RPF to work with policy routing

Policy routing is not looked up by mark on reverse path filtering.
This fixes it.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -210,7 +210,8 @@ extern struct fib_table *fib_get_table(struct net *net, u32 id);
 extern const struct nla_policy rtm_ipv4_policy[];
 extern void		ip_fib_init(void);
 extern int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
-			       struct net_device *dev, __be32 *spec_dst, u32 *itag);
+			       struct net_device *dev, __be32 *spec_dst,
+			       u32 *itag, u32 mark);
 extern void fib_select_default(struct net *net, const struct flowi *flp,
 			       struct fib_result *res);
 

net/ipv4/fib_frontend.c

@@ -229,14 +229,17 @@ unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
  */
 
 int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
-			struct net_device *dev, __be32 *spec_dst, u32 *itag)
+			struct net_device *dev, __be32 *spec_dst,
+			u32 *itag, u32 mark)
 {
 	struct in_device *in_dev;
 	struct flowi fl = { .nl_u = { .ip4_u =
 				      { .daddr = src,
 					.saddr = dst,
 					.tos = tos } },
+			    .mark = mark,
 			    .iif = oif };
+
 	struct fib_result res;
 	int no_addr, rpf;
 	int ret;

net/ipv4/route.c

@@ -1854,7 +1854,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 			goto e_inval;
 		spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
 	} else if (fib_validate_source(saddr, 0, tos, 0,
-					dev, &spec_dst, &itag) < 0)
+					dev, &spec_dst, &itag, 0) < 0)
 		goto e_inval;
 
 	rth = dst_alloc(&ipv4_dst_ops);
@@ -1967,7 +1967,7 @@ static int __mkroute_input(struct sk_buff *skb,
 
 
 	err = fib_validate_source(saddr, daddr, tos, FIB_RES_OIF(*res),
-				  in_dev->dev, &spec_dst, &itag);
+				  in_dev->dev, &spec_dst, &itag, skb->mark);
 	if (err < 0) {
 		ip_handle_martian_source(in_dev->dev, in_dev, skb, daddr,
 					 saddr);
@@ -2141,7 +2141,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		int result;
 		result = fib_validate_source(saddr, daddr, tos,
 					     net->loopback_dev->ifindex,
-					     dev, &spec_dst, &itag);
+					     dev, &spec_dst, &itag, skb->mark);
 		if (result < 0)
 			goto martian_source;
 		if (result)
@@ -2170,7 +2170,7 @@ brd_input:
 		spec_dst = inet_select_addr(dev, 0, RT_SCOPE_LINK);
 	else {
 		err = fib_validate_source(saddr, 0, tos, 0, dev, &spec_dst,
-					  &itag);
+					  &itag, skb->mark);
 		if (err < 0)
 			goto martian_source;
 		if (err)