net: erspan: refactor existing erspan code

The patch refactors the existing erspan implementation in order
to support erspan version 2, which has additional metadata.  So, in
stead of having one 'struct erspanhdr' holding erspan version 1,
breaks it into 'struct erspan_base_hdr' and 'struct erspan_metadata'.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 10 deletions

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index d828821d88d7..3e37402147f3 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -256,34 +256,41 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 {
 	struct net *net = dev_net(skb->dev);
 	struct metadata_dst *tun_dst = NULL;
+	struct erspan_base_hdr *ershdr;
+	struct erspan_metadata *pkt_md;
 	struct ip_tunnel_net *itn;
 	struct ip_tunnel *tunnel;
-	struct erspanhdr *ershdr;
 	const struct iphdr *iph;
-	__be32 index;
+	int ver;
 	int len;
 
 	itn = net_generic(net, erspan_net_id);
 	len = gre_hdr_len + sizeof(*ershdr);
 
+	/* Check based hdr len */
 	if (unlikely(!pskb_may_pull(skb, len)))
 		return -ENOMEM;
 
 	iph = ip_hdr(skb);
-	ershdr = (struct erspanhdr *)(skb->data + gre_hdr_len);
+	ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
+	ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
 
 	/* The original GRE header does not have key field,
 	 * Use ERSPAN 10-bit session ID as key.
 	 */
 	tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
-	index = ershdr->md.index;
+	pkt_md = (struct erspan_metadata *)(ershdr + 1);
 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
 				  tpi->flags | TUNNEL_KEY,
 				  iph->saddr, iph->daddr, tpi->key);
 
 	if (tunnel) {
+		len = gre_hdr_len + erspan_hdr_len(ver);
+		if (unlikely(!pskb_may_pull(skb, len)))
+			return -ENOMEM;
+
 		if (__iptunnel_pull_header(skb,
-					   gre_hdr_len + sizeof(*ershdr),
+					   len,
 					   htons(ETH_P_TEB),
 					   false, false) < 0)
 			goto drop;
@@ -307,12 +314,12 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 			if (!md)
 				return PACKET_REJECT;
 
-			md->index = index;
+			memcpy(md, pkt_md, sizeof(*md));
 			info = &tun_dst->u.tun_info;
 			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 			info->options_len = sizeof(*md);
 		} else {
-			tunnel->index = ntohl(index);
+			tunnel->index = ntohl(pkt_md->u.index);
 		}
 
 		skb_reset_mac_header(skb);
@@ -571,7 +578,7 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 	key = &tun_info->key;
 
 	/* ERSPAN has fixed 8 byte GRE header */
-	tunnel_hlen = 8 + sizeof(struct erspanhdr);
+	tunnel_hlen = 8 + sizeof(struct erspan_base_hdr) + ERSPAN_V1_MDSIZE;
 
 	rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
 	if (!rt)
@@ -590,7 +597,7 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 		goto err_free_rt;
 
 	erspan_build_header(skb, tunnel_id_to_key32(key->tun_id),
-			    ntohl(md->index), truncate, true);
+			    ntohl(md->u.index), truncate, true);
 
 	gre_build_header(skb, 8, TUNNEL_SEQ,
 			 htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));
@@ -1238,7 +1245,7 @@ static int erspan_tunnel_init(struct net_device *dev)
 	tunnel->tun_hlen = 8;
 	tunnel->parms.iph.protocol = IPPROTO_GRE;
 	tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
-		       sizeof(struct erspanhdr);
+		       sizeof(struct erspan_base_hdr) + ERSPAN_V1_MDSIZE;
 	t_hlen = tunnel->hlen + sizeof(struct iphdr);
 
 	dev->needed_headroom = LL_MAX_HEADER + t_hlen + 4;