+++ /dev/null
-From: Pablo Neira Ayuso <pablo@netfilter.org>
-Date: Wed, 24 Mar 2021 02:30:32 +0100
-Subject: [PATCH] net: resolve forwarding path from virtual netdevice and
- HW destination address
-
-This patch adds dev_fill_forward_path() which resolves the path to reach
-the real netdevice from the IP forwarding side. This function takes as
-input the netdevice and the destination hardware address and it walks
-down the devices calling .ndo_fill_forward_path() for each device until
-the real device is found.
-
-For instance, assuming the following topology:
-
- IP forwarding
- / \
- br0 eth0
- / \
- eth1 eth2
- .
- .
- .
- ethX
- ab:cd:ef:ab:cd:ef
-
-where eth1 and eth2 are bridge ports and eth0 provides WAN connectivity.
-ethX is the interface in another box which is connected to the eth1
-bridge port.
-
-For packets going through IP forwarding to br0 whose destination MAC
-address is ab:cd:ef:ab:cd:ef, dev_fill_forward_path() provides the
-following path:
-
- br0 -> eth1
-
-.ndo_fill_forward_path for br0 looks up at the FDB for the bridge port
-from the destination MAC address to get the bridge port eth1.
-
-This information allows to create a fast path that bypasses the classic
-bridge and IP forwarding paths, so packets go directly from the bridge
-port eth1 to eth0 (wan interface) and vice versa.
-
- fast path
- .------------------------.
- / \
- | IP forwarding |
- | / \ \/
- | br0 eth0
- . / \
- -> eth1 eth2
- .
- .
- .
- ethX
- ab:cd:ef:ab:cd:ef
-
-Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
----
-
---- a/include/linux/netdevice.h
-+++ b/include/linux/netdevice.h
-@@ -850,6 +850,27 @@ typedef u16 (*select_queue_fallback_t)(s
- struct sk_buff *skb,
- struct net_device *sb_dev);
-
-+enum net_device_path_type {
-+ DEV_PATH_ETHERNET = 0,
-+};
-+
-+struct net_device_path {
-+ enum net_device_path_type type;
-+ const struct net_device *dev;
-+};
-+
-+#define NET_DEVICE_PATH_STACK_MAX 5
-+
-+struct net_device_path_stack {
-+ int num_paths;
-+ struct net_device_path path[NET_DEVICE_PATH_STACK_MAX];
-+};
-+
-+struct net_device_path_ctx {
-+ const struct net_device *dev;
-+ const u8 *daddr;
-+};
-+
- enum tc_setup_type {
- TC_SETUP_QDISC_MQPRIO,
- TC_SETUP_CLSU32,
-@@ -1296,6 +1317,8 @@ struct netdev_net_notifier {
- * struct net_device *(*ndo_get_peer_dev)(struct net_device *dev);
- * If a device is paired with a peer device, return the peer instance.
- * The caller must be under RCU read context.
-+ * int (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx, struct net_device_path *path);
-+ * Get the forwarding path to reach the real device from the HW destination address
- */
- struct net_device_ops {
- int (*ndo_init)(struct net_device *dev);
-@@ -1504,6 +1527,8 @@ struct net_device_ops {
- int (*ndo_tunnel_ctl)(struct net_device *dev,
- struct ip_tunnel_parm *p, int cmd);
- struct net_device * (*ndo_get_peer_dev)(struct net_device *dev);
-+ int (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx,
-+ struct net_device_path *path);
- };
-
- /**
-@@ -2851,6 +2876,8 @@ void dev_remove_offload(struct packet_of
-
- int dev_get_iflink(const struct net_device *dev);
- int dev_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb);
-+int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
-+ struct net_device_path_stack *stack);
- struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags,
- unsigned short mask);
- struct net_device *dev_get_by_name(struct net *net, const char *name);
---- a/net/core/dev.c
-+++ b/net/core/dev.c
-@@ -847,6 +847,52 @@ int dev_fill_metadata_dst(struct net_dev
- }
- EXPORT_SYMBOL_GPL(dev_fill_metadata_dst);
-
-+static struct net_device_path *dev_fwd_path(struct net_device_path_stack *stack)
-+{
-+ int k = stack->num_paths++;
-+
-+ if (WARN_ON_ONCE(k >= NET_DEVICE_PATH_STACK_MAX))
-+ return NULL;
-+
-+ return &stack->path[k];
-+}
-+
-+int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
-+ struct net_device_path_stack *stack)
-+{
-+ const struct net_device *last_dev;
-+ struct net_device_path_ctx ctx = {
-+ .dev = dev,
-+ .daddr = daddr,
-+ };
-+ struct net_device_path *path;
-+ int ret = 0;
-+
-+ stack->num_paths = 0;
-+ while (ctx.dev && ctx.dev->netdev_ops->ndo_fill_forward_path) {
-+ last_dev = ctx.dev;
-+ path = dev_fwd_path(stack);
-+ if (!path)
-+ return -1;
-+
-+ memset(path, 0, sizeof(struct net_device_path));
-+ ret = ctx.dev->netdev_ops->ndo_fill_forward_path(&ctx, path);
-+ if (ret < 0)
-+ return -1;
-+
-+ if (WARN_ON_ONCE(last_dev == ctx.dev))
-+ return -1;
-+ }
-+ path = dev_fwd_path(stack);
-+ if (!path)
-+ return -1;
-+ path->type = DEV_PATH_ETHERNET;
-+ path->dev = ctx.dev;
-+
-+ return ret;
-+}
-+EXPORT_SYMBOL_GPL(dev_fill_forward_path);
-+
- /**
- * __dev_get_by_name - find a device by its name
- * @net: the applicable net namespace
projects / openwrt / openwrt.git / blobdiff