net: Add routes to the table associated with the device

When a device associated with a VRF is brought up or down routes
should be added to/removed from the table associated with the VRF.
fib_magic defaults to using the main or local tables. Have it use
the table with the device if there is one.

A part of this is directing prefsrc validations to the correct
table as well.
Signed-off-by: NDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/fib_frontend.c

@@ -800,6 +800,7 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
 {
 	struct net *net = dev_net(ifa->ifa_dev->dev);
+	int tb_id = vrf_dev_table_rtnl(ifa->ifa_dev->dev);
 	struct fib_table *tb;
 	struct fib_config cfg = {
 		.fc_protocol = RTPROT_KERNEL,
@@ -814,11 +815,10 @@ static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifad
 		},
 	};
 
-	if (type == RTN_UNICAST)
-		tb = fib_new_table(net, RT_TABLE_MAIN);
-	else
-		tb = fib_new_table(net, RT_TABLE_LOCAL);
+	if (!tb_id)
+		tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
 
+	tb = fib_new_table(net, tb_id);
 	if (!tb)
 		return;
 

net/ipv4/fib_semantics.c

@@ -838,6 +838,23 @@ __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
 	return nh->nh_saddr;
 }
 
+static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
+{
+	if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
+	    fib_prefsrc != cfg->fc_dst) {
+		int tb_id = cfg->fc_table;
+
+		if (tb_id == RT_TABLE_MAIN)
+			tb_id = RT_TABLE_LOCAL;
+
+		if (inet_addr_type_table(cfg->fc_nlinfo.nl_net,
+					 fib_prefsrc, tb_id) != RTN_LOCAL) {
+			return false;
+		}
+	}
+	return true;
+}
+
 struct fib_info *fib_create_info(struct fib_config *cfg)
 {
 	int err;
@@ -1033,12 +1050,8 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 			fi->fib_flags |= RTNH_F_LINKDOWN;
 	}
 
-	if (fi->fib_prefsrc) {
-		if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
-		    fi->fib_prefsrc != cfg->fc_dst)
-			if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
+	if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
 		goto err_inval;
-	}
 
 	change_nexthops(fi) {
 		fib_info_update_nh_saddr(net, nexthop_nh);