datapath: Fix pop_vlan().

Following patch fixes bug in pop_vlan code by updating ethernet
header len.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>

3 files changed, 46 insertions, 7 deletions

diff --git a/datapath/actions.c b/datapath/actions.c
index b430090c..70fe153a 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -50,8 +50,7 @@ static int make_writable(struct sk_buff *skb, int write_len)
 /* remove VLAN header from packet and update csum accrodingly. */
 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 {
-	struct ethhdr *eh;
-	struct vlan_ethhdr *veth;
+	struct vlan_hdr *vhdr;
 	int err;
 
 	err = make_writable(skb, VLAN_ETH_HLEN);
@@ -62,15 +61,15 @@ static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 		skb->csum = csum_sub(skb->csum, csum_partial(skb->data
 					+ ETH_HLEN, VLAN_HLEN, 0));
 
-	veth = (struct vlan_ethhdr *) skb->data;
-	*current_tci = veth->h_vlan_TCI;
+	vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
+	*current_tci = vhdr->h_vlan_TCI;
 
 	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
+	__skb_pull(skb, VLAN_HLEN);
 
-	eh = (struct ethhdr *)__skb_pull(skb, VLAN_HLEN);
-
-	skb->protocol = eh->h_proto;
+	vlan_set_encap_proto(skb, vhdr);
 	skb->mac_header += VLAN_HLEN;
+	skb_reset_mac_len(skb);
 
 	return 0;
 }
diff --git a/datapath/linux/compat/include/linux/if_vlan.h b/datapath/linux/compat/include/linux/if_vlan.h
index f4184074..326abb27 100644
--- a/datapath/linux/compat/include/linux/if_vlan.h
+++ b/datapath/linux/compat/include/linux/if_vlan.h
@@ -54,4 +54,38 @@ static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
 #define VLAN_TAG_PRESENT	VLAN_CFI_MASK
 #endif
 
+/* This function is not exported from kernel. OVS Upstreaming patch will
+ * fix that. */
+static inline void vlan_set_encap_proto(struct sk_buff *skb, struct vlan_hdr *vhdr)
+{
+	__be16 proto;
+	unsigned char *rawp;
+
+	/*
+	 * Was a VLAN packet, grab the encapsulated protocol, which the layer
+	 * three protocols care about.
+	 */
+
+	proto = vhdr->h_vlan_encapsulated_proto;
+	if (ntohs(proto) >= 1536) {
+		skb->protocol = proto;
+		return;
+	}
+
+	rawp = skb->data;
+	if (*(unsigned short *) rawp == 0xFFFF)
+		/*
+		 * This is a magic hack to spot IPX packets. Older Novell
+		 * breaks the protocol design and runs IPX over 802.3 without
+		 * an 802.2 LLC layer. We look for FFFF which isn't a used
+		 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
+		 * but does for the rest.
+		 */
+		skb->protocol = htons(ETH_P_802_3);
+	else
+		/*
+		 * Real 802.2 LLC
+		 */
+		skb->protocol = htons(ETH_P_802_2);
+}
 #endif	/* linux/if_vlan.h wrapper */
diff --git a/datapath/linux/compat/include/linux/skbuff.h b/datapath/linux/compat/include/linux/skbuff.h
index 456d7446..311bfdbc 100644
--- a/datapath/linux/compat/include/linux/skbuff.h
+++ b/datapath/linux/compat/include/linux/skbuff.h
@@ -239,4 +239,10 @@ static inline struct page *skb_frag_page(const skb_frag_t *frag)
 }
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,0,0)
+static inline void skb_reset_mac_len(struct sk_buff *skb)
+{
+	skb->mac_len = skb->network_header - skb->mac_header;
+}
+#endif
 #endif