[PATCH net-next 3/9] net: 8021q: resolve forwarding path for vlan devices

[Pablo Neira Ayuso]

Add .ndo_fill_forward_path for vlan devices.

For instance, assuming the following topology:

                   IP forwarding
                  /             \
            eth0.100             eth0
            |
            eth0
            .
            .
            .
           ethX
     ab:cd:ef:ab:cd:ef

For packets in the IP forwarding going to eth0.100 whose destination MAC
address is ab:cd:ef:ab:cd:ef, dev_fill_forward_path() provides the
following path:

            eth0.100 -> eth0

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 include/linux/netdevice.h |  7 +++++++
 net/8021q/vlan_dev.c      | 15 +++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index b77960621c27..6a3370fafe4b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -835,11 +835,18 @@ typedef u16 (*select_queue_fallback_t)(struct net_device 
*dev,
 
 enum net_device_path_type {
        DEV_PATH_ETHERNET = 0,
+       DEV_PATH_VLAN,
 };
 
 struct net_device_path {
        enum net_device_path_type       type;
        const struct net_device         *dev;
+       union {
+               struct {
+                       __be16          id;
+                       __be16          proto;
+               } vlan;
+       };
 };
 
 #define NET_DEVICE_PATH_STACK_MAX      5
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index ec8408d1638f..f06a507557f9 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -767,6 +767,20 @@ static int vlan_dev_get_iflink(const struct net_device 
*dev)
        return real_dev->ifindex;
 }
 
+static int vlan_dev_fill_forward_path(struct net_device_path_ctx *ctx,
+                                     struct net_device_path *path)
+{
+       struct vlan_dev_priv *vlan = vlan_dev_priv(ctx->dev);
+
+       path->type = DEV_PATH_VLAN;
+       path->vlan.id = vlan->vlan_id;
+       path->vlan.proto = vlan->vlan_proto;
+       path->dev = ctx->dev;
+       ctx->dev = vlan->real_dev;
+
+       return 0;
+}
+
 static const struct ethtool_ops vlan_ethtool_ops = {
        .get_link_ksettings     = vlan_ethtool_get_link_ksettings,
        .get_drvinfo            = vlan_ethtool_get_drvinfo,
@@ -805,6 +819,7 @@ static const struct net_device_ops vlan_netdev_ops = {
 #endif
        .ndo_fix_features       = vlan_dev_fix_features,
        .ndo_get_iflink         = vlan_dev_get_iflink,
+       .ndo_fill_forward_path  = vlan_dev_fill_forward_path,
 };
 
 static void vlan_dev_free(struct net_device *dev)
-- 
2.20.1