Subject: [PATCH RFC v1 net-next 06/12] net: core: dev: Add dev_fill_bridge_path()

From: Eric Woudstra <[email-masked]>
Date: Sun, 13 Oct 2024 20:55:02 +0200

New function dev_fill_bridge_path(), similar to dev_fill_forward_path().
It handles starting from a bridge port instead of the bridge master.
The structures ctx and nft_forward_info need to be already filled in with
the (vlan) encaps.

Signed-off-by: Eric Woudstra <[email-masked]>
---
 include/linux/netdevice.h |  2 +
 net/core/dev.c            | 77 ++++++++++++++++++++++++++++++++-------
 2 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e87b5e488325..9d80f650345e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3069,6 +3069,8 @@ void dev_remove_offload(struct packet_offload *po);
 
 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_bridge_path(struct net_device_path_ctx *ctx,
+			 struct net_device_path_stack *stack);
 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,
diff --git a/net/core/dev.c b/net/core/dev.c
index cd479f5f22f6..49959c4904fc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -713,44 +713,95 @@ static struct net_device_path *dev_fwd_path(struct net_device_path_stack *stack)
 	return &stack->path[k];
 }
 
-int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
-			  struct net_device_path_stack *stack)
+static int dev_fill_forward_path_common(struct net_device_path_ctx *ctx,
+					struct net_device_path_stack *stack)
 {
 	const struct net_device *last_dev;
-	struct net_device_path_ctx ctx = {
-		.dev	= dev,
-	};
 	struct net_device_path *path;
 	int ret = 0;
 
-	memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
-	stack->num_paths = 0;
-	while (ctx.dev && ctx.dev->netdev_ops->ndo_fill_forward_path) {
-		last_dev = ctx.dev;
+	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);
+		ret = ctx->dev->netdev_ops->ndo_fill_forward_path(ctx, path);
 		if (ret < 0)
 			return -1;
 
-		if (WARN_ON_ONCE(last_dev == ctx.dev))
+		if (WARN_ON_ONCE(last_dev == ctx->dev))
 			return -1;
 	}
 
-	if (!ctx.dev)
+	if (!ctx->dev)
 		return ret;
 
 	path = dev_fwd_path(stack);
 	if (!path)
 		return -1;
 	path->type = DEV_PATH_ETHERNET;
-	path->dev = ctx.dev;
+	path->dev = ctx->dev;
+
+	return ret;
+}
+
+int dev_fill_bridge_path(struct net_device_path_ctx *ctx,
+			 struct net_device_path_stack *stack)
+{
+	const struct net_device *last_dev, *br_dev;
+	struct net_device_path *path;
+	int ret = 0;
+
+	stack->num_paths = 0;
+
+	if (!ctx->dev || !netif_is_bridge_port(ctx->dev))
+		return -1;
+
+	br_dev = netdev_master_upper_dev_get_rcu((struct net_device *)ctx->dev);
+	if (!br_dev || !br_dev->netdev_ops->ndo_fill_forward_path)
+		return -1;
+
+	last_dev = ctx->dev;
+	path = dev_fwd_path(stack);
+	if (!path)
+		return -1;
+
+	memset(path, 0, sizeof(struct net_device_path));
+	ret = br_dev->netdev_ops->ndo_fill_forward_path(ctx, path);
+	if (ret < 0)
+		return -1;
+
+	if (!ctx->dev || WARN_ON_ONCE(last_dev == ctx->dev))
+		return -1;
+
+	if (!netif_is_bridge_master(ctx->dev))
+		return dev_fill_forward_path_common(ctx, stack);
+
+	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_bridge_path);
+
+int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
+			  struct net_device_path_stack *stack)
+{
+	struct net_device_path_ctx ctx = {
+		.dev	= dev,
+	};
+
+	memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
+
+	stack->num_paths = 0;
+
+	return dev_fill_forward_path_common(&ctx, stack);
+}
 EXPORT_SYMBOL_GPL(dev_fill_forward_path);
 
 /**
-- 
2.45.2