[PATCH net-next 05/17] netfilter: flowtable: inline pppoe encapsulation in xmit path

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

Push the pppoe header from the flowtable xmit path, inlining is faster
than the original xmit path because it can avoid some locking.

This is based on a patch originally written by wenxu.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_flow_table_ip.c   | 42 ++++++++++++++++++++++++++++++
 net/netfilter/nf_flow_table_path.c |  9 ++-----
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index aef799edca9f..ee6ec63257d1 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -413,6 +413,44 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,
 	return 1;
 }
 
+static int nf_flow_pppoe_push(struct sk_buff *skb, u16 id)
+{
+	int data_len = skb->len + sizeof(__be16);
+	struct ppp_hdr {
+		struct pppoe_hdr hdr;
+		__be16 proto;
+	} *ph;
+	__be16 proto;
+
+	if (skb_cow_head(skb, PPPOE_SES_HLEN))
+		return -1;
+
+	switch (skb->protocol) {
+	case htons(ETH_P_IP):
+		proto = htons(PPP_IP);
+		break;
+	case htons(ETH_P_IPV6):
+		proto = htons(PPP_IPV6);
+		break;
+	default:
+		return -1;
+	}
+
+	__skb_push(skb, PPPOE_SES_HLEN);
+	skb_reset_network_header(skb);
+
+	ph = (struct ppp_hdr *)(skb->data);
+	ph->hdr.ver	= 1;
+	ph->hdr.type	= 1;
+	ph->hdr.code	= 0;
+	ph->hdr.sid	= htons(id);
+	ph->hdr.length	= htons(data_len);
+	ph->proto	= proto;
+	skb->protocol	= htons(ETH_P_PPP_SES);
+
+	return 0;
+}
+
 static int nf_flow_encap_push(struct sk_buff *skb,
 			      struct flow_offload_tuple *tuple)
 {
@@ -426,6 +464,10 @@ static int nf_flow_encap_push(struct sk_buff *skb,
 					  tuple->encap[i].id) < 0)
 				return -1;
 			break;
+		case htons(ETH_P_PPP_SES):
+			if (nf_flow_pppoe_push(skb, tuple->encap[i].id) < 0)
+				return -1;
+			break;
 		}
 	}
 
diff --git a/net/netfilter/nf_flow_table_path.c b/net/netfilter/nf_flow_table_path.c
index 38ebda1afdce..c51e310bb2ab 100644
--- a/net/netfilter/nf_flow_table_path.c
+++ b/net/netfilter/nf_flow_table_path.c
@@ -122,11 +122,8 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 			info->encap[info->num_encaps].id = path->encap.id;
 			info->encap[info->num_encaps].proto = path->encap.proto;
 			info->num_encaps++;
-			if (path->type == DEV_PATH_PPPOE) {
-				if (!info->outdev)
-					info->outdev = path->dev;
+			if (path->type == DEV_PATH_PPPOE)
 				memcpy(info->h_dest, path->encap.h_dest, ETH_ALEN);
-			}
 			break;
 		case DEV_PATH_BRIDGE:
 			if (is_zero_ether_addr(info->h_source))
@@ -161,9 +158,7 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 			break;
 		}
 	}
-	if (!info->outdev)
-		info->outdev = info->indev;
-
+	info->outdev = info->indev;
 	info->hw_outdev = info->indev;
 
 	if (nf_flowtable_hw_offload(flowtable) &&
-- 
2.47.3