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Commit ed246cee authored by John Hurley's avatar John Hurley Committed by David S. Miller
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net: core: move pop MPLS functionality from OvS to core helper 



Open vSwitch provides code to pop an MPLS header to a packet. In
preparation for supporting this in TC, move the pop code to an skb helper
that can be reused.

Remove the, now unused, update_ethertype static function from OvS.

Signed-off-by: default avatarJohn Hurley <john.hurley@netronome.com>
Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarSimon Horman <simon.horman@netronome.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8822e270

include/linux/skbuff.h

+1 −0
Original line number Diff line number Diff line
@@ -3448,6 +3448,7 @@ int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci); 
int skb_vlan_pop(struct sk_buff *skb);

int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);

int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto);

int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto);

struct sk_buff *pskb_extract(struct sk_buff *skb, int off, int to_copy,

			     gfp_t gfp);

net/core/skbuff.c

+42 −0
Original line number Diff line number Diff line
@@ -5489,6 +5489,48 @@ int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto) 
}

EXPORT_SYMBOL_GPL(skb_mpls_push);



/**

 * skb_mpls_pop() - pop the outermost MPLS header

 *

 * @skb: buffer

 * @next_proto: ethertype of header after popped MPLS header

 *

 * Expects skb->data at mac header.

 *

 * Returns 0 on success, -errno otherwise.

 */

int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)

{

	int err;



	if (unlikely(!eth_p_mpls(skb->protocol)))

		return -EINVAL;



	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);

	if (unlikely(err))

		return err;



	skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);

	memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),

		skb->mac_len);



	__skb_pull(skb, MPLS_HLEN);

	skb_reset_mac_header(skb);

	skb_set_network_header(skb, skb->mac_len);



	if (skb->dev && skb->dev->type == ARPHRD_ETHER) {

		struct ethhdr *hdr;



		/* use mpls_hdr() to get ethertype to account for VLANs. */

		hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);

		skb_mod_eth_type(skb, hdr, next_proto);

	}

	skb->protocol = next_proto;



	return 0;

}

EXPORT_SYMBOL_GPL(skb_mpls_pop);



/**

 * alloc_skb_with_frags - allocate skb with page frags

 *

net/openvswitch/actions.c

+2 −35
Original line number Diff line number Diff line
@@ -160,18 +160,6 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, 
			      struct sw_flow_key *key,

			      const struct nlattr *attr, int len);



static void update_ethertype(struct sk_buff *skb, struct ethhdr *hdr,

			     __be16 ethertype)

{

	if (skb->ip_summed == CHECKSUM_COMPLETE) {

		__be16 diff[] = { ~(hdr->h_proto), ethertype };



		skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);

	}



	hdr->h_proto = ethertype;

}



static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,

		     const struct ovs_action_push_mpls *mpls)

{
@@ -190,31 +178,10 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key, 
{

	int err;



	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);

	if (unlikely(err))

	err = skb_mpls_pop(skb, ethertype);

	if (err)

		return err;



	skb_postpull_rcsum(skb, mpls_hdr(skb), MPLS_HLEN);



	memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),

		skb->mac_len);



	__skb_pull(skb, MPLS_HLEN);

	skb_reset_mac_header(skb);

	skb_set_network_header(skb, skb->mac_len);



	if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET) {

		struct ethhdr *hdr;



		/* mpls_hdr() is used to locate the ethertype field correctly in the

		 * presence of VLAN tags.

		 */

		hdr = (struct ethhdr *)((void *)mpls_hdr(skb) - ETH_HLEN);

		update_ethertype(skb, hdr, ethertype);

	}

	if (eth_p_mpls(skb->protocol))

		skb->protocol = ethertype;



	invalidate_flow_key(key);

	return 0;

}