ip_tunnel: push generic protocol handling to ip_tunnel module.

Process skb tunnel header before sending packet to protocol handler.
this allows code sharing between gre and ovs gre modules.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_tunnels.h

@@ -155,6 +155,7 @@ static inline void tunnel_ip_select_ident(struct sk_buff *skb,
 				  (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 }
 
+int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto);
 int iptunnel_xmit(struct net *net, struct rtable *rt,
 		  struct sk_buff *skb,
 		  __be32 src, __be32 dst, __u8 proto,

net/ipv4/gre.c

@@ -201,7 +201,8 @@ static int parse_gre_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 				return -EINVAL;
 		}
 	}
-	return 0;
+
+	return iptunnel_pull_header(skb, hdr_len, tpi->proto);
 }
 
 static int gre_cisco_rcv(struct sk_buff *skb)

net/ipv4/ip_tunnel.c

@@ -408,13 +408,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 	const struct iphdr *iph = ip_hdr(skb);
 	int err;
 
-	secpath_reset(skb);
-
-	skb->protocol = tpi->proto;
-
-	skb->mac_header = skb->network_header;
-	__pskb_pull(skb, tunnel->hlen);
-	skb_postpull_rcsum(skb, skb_transport_header(skb), tunnel->hlen);
 #ifdef CONFIG_NET_IPGRE_BROADCAST
 	if (ipv4_is_multicast(iph->daddr)) {
 		/* Looped back packet, drop it! */
@@ -442,23 +435,6 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 		tunnel->i_seqno = ntohl(tpi->seq) + 1;
 	}
 
-	/* Warning: All skb pointers will be invalidated! */
-	if (tunnel->dev->type == ARPHRD_ETHER) {
-		if (!pskb_may_pull(skb, ETH_HLEN)) {
-			tunnel->dev->stats.rx_length_errors++;
-			tunnel->dev->stats.rx_errors++;
-			goto drop;
-		}
-
-		iph = ip_hdr(skb);
-		skb->protocol = eth_type_trans(skb, tunnel->dev);
-		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
-	}
-
-	skb->pkt_type = PACKET_HOST;
-	__skb_tunnel_rx(skb, tunnel->dev);
-
-	skb_reset_network_header(skb);
 	err = IP_ECN_decapsulate(iph, skb);
 	if (unlikely(err)) {
 		if (log_ecn_error)
@@ -477,6 +453,12 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 	tstats->rx_bytes += skb->len;
 	u64_stats_update_end(&tstats->syncp);
 
+	if (tunnel->dev->type == ARPHRD_ETHER) {
+		skb->protocol = eth_type_trans(skb, tunnel->dev);
+		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
+	} else {
+		skb->dev = tunnel->dev;
+	}
 	gro_cells_receive(&tunnel->gro_cells, skb);
 	return 0;
 

net/ipv4/ip_tunnel_core.c

@@ -86,3 +86,37 @@ int iptunnel_xmit(struct net *net, struct rtable *rt,
 	return pkt_len;
 }
 EXPORT_SYMBOL_GPL(iptunnel_xmit);
+
+int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
+{
+	if (unlikely(!pskb_may_pull(skb, hdr_len)))
+		return -ENOMEM;
+
+	skb_pull_rcsum(skb, hdr_len);
+
+	if (inner_proto == htons(ETH_P_TEB)) {
+		struct ethhdr *eh = (struct ethhdr *)skb->data;
+
+		if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
+			return -ENOMEM;
+
+		if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN))
+			skb->protocol = eh->h_proto;
+		else
+			skb->protocol = htons(ETH_P_802_2);
+
+	} else {
+		skb->protocol = inner_proto;
+	}
+
+	nf_reset(skb);
+	secpath_reset(skb);
+	if (!skb->l4_rxhash)
+		skb->rxhash = 0;
+	skb_dst_drop(skb);
+	skb->vlan_tci = 0;
+	skb_set_queue_mapping(skb, 0);
+	skb->pkt_type = PACKET_HOST;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iptunnel_pull_header);

net/ipv4/ipip.c

@@ -188,8 +188,12 @@ static int ipip_rcv(struct sk_buff *skb)
 	struct net *net = dev_net(skb->dev);
 	struct ip_tunnel_net *itn = net_generic(net, ipip_net_id);
 	struct ip_tunnel *tunnel;
-	const struct iphdr *iph = ip_hdr(skb);
+	const struct iphdr *iph;
 
+	if (iptunnel_pull_header(skb, 0, tpi.proto))
+		goto drop;
+
+	iph = ip_hdr(skb);
 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
 			iph->saddr, iph->daddr, 0);
 	if (tunnel) {

net/ipv6/sit.c

@@ -640,9 +640,14 @@ static const struct tnl_ptk_info tpi = {
 
 static int ipip_rcv(struct sk_buff *skb)
 {
-	const struct iphdr *iph = ip_hdr(skb);
+	const struct iphdr *iph;
 	struct ip_tunnel *tunnel;
 
+	if (iptunnel_pull_header(skb, 0, tpi.proto))
+		goto drop;
+
+	iph = ip_hdr(skb);
+
 	tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 				     iph->saddr, iph->daddr);
 	if (tunnel != NULL) {