[PATCH nf-next,v1 2/4] net: pass net_device_path_ctx struct to dev_fill_forward_path()

[Pablo Neira Ayuso <pablo@netfilter.org>]

Generalize dev_fill_forward_path() so it can be used by the bridge
family to retrieve the bridge vlan filtering information from the
bridge port when discovering the bridge flowtable path.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v1: A different approach compared to Eric Woudstra's proposal to
    add another function to the net core for the bridge case.
    I am leaning towards making a simple generalization and keep
    the bridge vlan filtering path discovery special case under
    the flowtable at this stage.

 include/linux/netdevice.h          |  2 +-
 net/core/dev.c                     | 18 +++++++-----------
 net/netfilter/nf_flow_table_path.c | 12 +++++++++++-
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 07bf265d0295..41cd092b032c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3420,7 +3420,7 @@ 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_forward_path(const struct net_device *dev, const u8 *daddr,
+int dev_fill_forward_path(struct net_device_path_ctx *ctx,
 			  struct net_device_path_stack *stack);
 struct net_device *dev_get_by_name(struct net *net, const char *name);
 struct net_device *dev_get_by_name_rcu(struct net *net, const char *name);
diff --git a/net/core/dev.c b/net/core/dev.c
index 4b3d5cfdf6e0..9a065c286d92 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -750,41 +750,37 @@ 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,
+int dev_fill_forward_path(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;
 }
diff --git a/net/netfilter/nf_flow_table_path.c b/net/netfilter/nf_flow_table_path.c
index 98c03b487f52..007e9781902a 100644
--- a/net/netfilter/nf_flow_table_path.c
+++ b/net/netfilter/nf_flow_table_path.c
@@ -42,6 +42,14 @@ static bool nft_is_valid_ether_device(const struct net_device *dev)
 	return true;
 }
 
+static void nft_dev_fill_forward_path_init(struct net_device_path_ctx *ctx,
+					   const struct net_device *dev, const u8 *daddr)
+{
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->dev	= dev;
+	memcpy(ctx->daddr, daddr, sizeof(ctx->daddr));
+}
+
 static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
 				     const struct dst_entry *dst_cache,
 				     const struct nf_conn *ct,
@@ -50,6 +58,7 @@ static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
 {
 	const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
 	struct net_device *dev = dst_cache->dev;
+	struct net_device_path_ctx ctx;
 	struct neighbour *n;
 	u8 nud_state;
 
@@ -71,8 +80,9 @@ static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
 	if (!(nud_state & NUD_VALID))
 		return -1;
 
+	nft_dev_fill_forward_path_init(&ctx, dev, ha);
 out:
-	return dev_fill_forward_path(dev, ha, stack);
+	return dev_fill_forward_path(&ctx, stack);
 }
 
 struct nft_forward_info {
-- 
2.47.3