path: root/net/l3mdev
diff options
authorDavid Ahern <dsa@cumulusnetworks.com>2016-02-24 11:47:02 -0800
committerDavid S. Miller <davem@davemloft.net>2016-02-26 14:22:26 -0500
commit3f2fb9a834cb1fcddbae22deca7fde136944dc89 (patch)
treee1c9a118cd24d84d3b53d0ad959b5d0eda0c570d /net/l3mdev
parent8d3f2806f8fbd9b222b3504580b5eaa9ba2964b8 (diff)
net: l3mdev: address selection should only consider devices in L3 domain
David Lamparter noted a use case where the source address selection fails to pick an address from a VRF interface - unnumbered interfaces. Relevant commands from his script: ip addr add dev lo ip link set lo up ip link add name vrf0 type vrf table 101 ip rule add oif vrf0 table 101 ip rule add iif vrf0 table 101 ip link set vrf0 up ip addr add dev vrf0 ip link add name dummy2 type dummy ip link set dummy2 master vrf0 up --> note dummy2 has no address - unnumbered device ip route add dev dummy2 table 101 ip neigh add dev dummy2 lladdr 02:00:00:00:00:02 tcpdump -ni dummy2 & And using ping instead of his socat example: $ ping -I vrf0 -c1 ping: Warning: source address might be selected on device other than vrf0. PING ( from vrf0: 56(84) bytes of data. >From tcpdump: 12:57:29.449128 IP > ICMP echo request, id 2491, seq 1, length 64 Note the source address is from lo and is not a VRF local address. With this patch: $ ping -I vrf0 -c1 PING ( from vrf0: 56(84) bytes of data. >From tcpdump: 12:59:25.096426 IP > ICMP echo request, id 2113, seq 1, length 64 Now the source address comes from vrf0. The ipv4 function for selecting source address takes a const argument. Removing the const requires touching a lot of places, so instead l3mdev_master_ifindex_rcu is changed to take a const argument and then do the typecast to non-const as required by netdev_master_upper_dev_get_rcu. This is similar to what l3mdev_fib_table_rcu does. IPv6 for unnumbered interfaces appears to be selecting the addresses properly. Cc: David Lamparter <david@opensourcerouting.org> Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/l3mdev')
1 files changed, 9 insertions, 2 deletions
diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c
index 8e5ead366e7f..e925037fa0df 100644
--- a/net/l3mdev/l3mdev.c
+++ b/net/l3mdev/l3mdev.c
@@ -17,7 +17,7 @@
* @dev: targeted interface
-int l3mdev_master_ifindex_rcu(struct net_device *dev)
+int l3mdev_master_ifindex_rcu(const struct net_device *dev)
int ifindex = 0;
@@ -28,8 +28,15 @@ int l3mdev_master_ifindex_rcu(struct net_device *dev)
ifindex = dev->ifindex;
} else if (netif_is_l3_slave(dev)) {
struct net_device *master;
+ struct net_device *_dev = (struct net_device *)dev;
- master = netdev_master_upper_dev_get_rcu(dev);
+ /* netdev_master_upper_dev_get_rcu calls
+ * list_first_or_null_rcu to walk the upper dev list.
+ * list_first_or_null_rcu does not handle a const arg. We aren't
+ * making changes, just want the master device from that list so
+ * typecast to remove the const
+ */
+ master = netdev_master_upper_dev_get_rcu(_dev);
if (master)
ifindex = master->ifindex;