Commit d4bcef3f authored by Toshiaki Makita's avatar Toshiaki Makita Committed by David S. Miller
Browse files

net: Fix vlan_get_protocol for stacked vlan 



vlan_get_protocol() could not get network protocol if a skb has a 802.1ad
vlan tag or multiple vlans, which caused incorrect checksum calculation
in several drivers.

Fix vlan_get_protocol() to retrieve network protocol instead of incorrect
vlan protocol.

As the logic is the same as skb_network_protocol(), create a common helper
function __vlan_get_protocol() and call it from existing functions.

Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cfbf654e

include/linux/if_vlan.h

+46 −14
Original line number Diff line number Diff line
@@ -472,27 +472,59 @@ static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci) 
/**

 * vlan_get_protocol - get protocol EtherType.

 * @skb: skbuff to query

 * @type: first vlan protocol

 * @depth: buffer to store length of eth and vlan tags in bytes

 *

 * Returns the EtherType of the packet, regardless of whether it is

 * vlan encapsulated (normal or hardware accelerated) or not.

 */

static inline __be16 vlan_get_protocol(const struct sk_buff *skb)

static inline __be16 __vlan_get_protocol(struct sk_buff *skb, __be16 type,

					 int *depth)

{

	__be16 protocol = 0;

	unsigned int vlan_depth = skb->mac_len;



	if (vlan_tx_tag_present(skb) ||

	     skb->protocol != cpu_to_be16(ETH_P_8021Q))

		protocol = skb->protocol;

	else {

		__be16 proto, *protop;

		protop = skb_header_pointer(skb, offsetof(struct vlan_ethhdr,

						h_vlan_encapsulated_proto),

						sizeof(proto), &proto);

		if (likely(protop))

			protocol = *protop;

	/* if type is 802.1Q/AD then the header should already be

	 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at

	 * ETH_HLEN otherwise

	 */

	if (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {

		if (vlan_depth) {

			if (WARN_ON(vlan_depth < VLAN_HLEN))

				return 0;

			vlan_depth -= VLAN_HLEN;

		} else {

			vlan_depth = ETH_HLEN;

		}

		do {

			struct vlan_hdr *vh;



			if (unlikely(!pskb_may_pull(skb,

						    vlan_depth + VLAN_HLEN)))

				return 0;



			vh = (struct vlan_hdr *)(skb->data + vlan_depth);

			type = vh->h_vlan_encapsulated_proto;

			vlan_depth += VLAN_HLEN;

		} while (type == htons(ETH_P_8021Q) ||

			 type == htons(ETH_P_8021AD));

	}



	if (depth)

		*depth = vlan_depth;



	return type;

}



	return protocol;

/**

 * vlan_get_protocol - get protocol EtherType.

 * @skb: skbuff to query

 *

 * Returns the EtherType of the packet, regardless of whether it is

 * vlan encapsulated (normal or hardware accelerated) or not.

 */

static inline __be16 vlan_get_protocol(struct sk_buff *skb)

{

	return __vlan_get_protocol(skb, skb->protocol, NULL);

}



static inline void vlan_set_encap_proto(struct sk_buff *skb,

net/core/dev.c

+1 −30
Original line number Diff line number Diff line
@@ -2352,7 +2352,6 @@ EXPORT_SYMBOL(skb_checksum_help); 


__be16 skb_network_protocol(struct sk_buff *skb, int *depth)

{

	unsigned int vlan_depth = skb->mac_len;

	__be16 type = skb->protocol;



	/* Tunnel gso handlers can set protocol to ethernet. */
@@ -2366,35 +2365,7 @@ __be16 skb_network_protocol(struct sk_buff *skb, int *depth) 
		type = eth->h_proto;

	}



	/* if skb->protocol is 802.1Q/AD then the header should already be

	 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at

	 * ETH_HLEN otherwise

	 */

	if (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {

		if (vlan_depth) {

			if (WARN_ON(vlan_depth < VLAN_HLEN))

				return 0;

			vlan_depth -= VLAN_HLEN;

		} else {

			vlan_depth = ETH_HLEN;

		}

		do {

			struct vlan_hdr *vh;



			if (unlikely(!pskb_may_pull(skb,

						    vlan_depth + VLAN_HLEN)))

				return 0;



			vh = (struct vlan_hdr *)(skb->data + vlan_depth);

			type = vh->h_vlan_encapsulated_proto;

			vlan_depth += VLAN_HLEN;

		} while (type == htons(ETH_P_8021Q) ||

			 type == htons(ETH_P_8021AD));

	}



	*depth = vlan_depth;



	return type;

	return __vlan_get_protocol(skb, type, depth);

}



/**

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