BACKPORT: net: ipv6: Fix processing of RAs in presence of VRF

commit 830218c1add1da16519b71909e5cf21522b7d062 upstream.

rt6_add_route_info and rt6_add_dflt_router were updated to pull the FIB
table from the device index, but the corresponding rt6_get_route_info
and rt6_get_dflt_router functions were not leading to the failure to
process RA's:

    ICMPv6: RA: ndisc_router_discovery failed to add default route

Fix the 'get' functions by using the table id associated with the
device when applicable.

Backported to 4.4 after
6dd69fdc001f7e "net: ipv6: autoconf routes into per-device tables"
which caused the conflicts due to which this had initially been reverted.

Resolved conflicts:
- Signatures and call sites already use `struct net_device`
  instead of `struct net` and `ifindex`
- The flag and the cleanup code using it are no longer required as
  `fib6_clean_all` is used to iterate over all tables.
- `l3mdev_fib_table_by_index` replaced by `l3mdev_fib_table`
  (prior incompletely resolved merge conflict)
- Use `RT6_TABLE_DFLT` instead of `RT6_TABLE_MAIN` in
  `rt6_get_dflt_router` (similar prior conflict as above)

Fixes: ca254490c8dfd ("net: Add VRF support to IPv6 stack")
Fixes: 6dd69fdc001f7 ("net: ipv6: autoconf routes into per-device tables")

Change-Id: I9b95895f840c89dc989986d4c12f5d4cc077e047

1 files changed, 5 insertions, 5 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index fd58f7feec8a..decb94219a70 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2310,12 +2310,12 @@ static struct rt6_info *rt6_get_route_info(struct net_device *dev,
 					   const struct in6_addr *prefix, int prefixlen,
 					   const struct in6_addr *gwaddr)
 {
+	u32 tb_id = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_INFO);
 	struct fib6_node *fn;
 	struct rt6_info *rt = NULL;
 	struct fib6_table *table;
 
-	table = fib6_get_table(dev_net(dev),
-			       addrconf_rt_table(dev, RT6_TABLE_INFO));
+	table = fib6_get_table(dev_net(dev), tb_id);
 	if (!table)
 		return NULL;
 
@@ -2354,7 +2354,7 @@ static struct rt6_info *rt6_add_route_info(struct net_device *dev,
 		.fc_nlinfo.nl_net = dev_net(dev),
 	};
 
-	cfg.fc_table = l3mdev_fib_table_by_index(dev_net(dev), dev->ifindex) ? : addrconf_rt_table(dev, RT6_TABLE_INFO);
+	cfg.fc_table = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_INFO);
 	cfg.fc_dst = *prefix;
 	cfg.fc_gateway = *gwaddr;
 
@@ -2370,11 +2370,11 @@ static struct rt6_info *rt6_add_route_info(struct net_device *dev,
 
 struct rt6_info *rt6_get_dflt_router(const struct in6_addr *addr, struct net_device *dev)
 {
+	u32 tb_id = l3mdev_fib_table(dev) ? : addrconf_rt_table(dev, RT6_TABLE_DFLT);
 	struct rt6_info *rt;
 	struct fib6_table *table;
 
-	table = fib6_get_table(dev_net(dev),
-			       addrconf_rt_table(dev, RT6_TABLE_MAIN));
+	table = fib6_get_table(dev_net(dev), tb_id);
 	if (!table)
 		return NULL;