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Commit d27cf5c5 authored by John Hurley's avatar John Hurley Committed by David S. Miller
Browse files

net: core: add MPLS update core helper and use in OvS 



Open vSwitch allows the updating of an existing MPLS header on a packet.
In preparation for supporting similar functionality in TC, move this to a
common skb helper function.

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 ed246cee

include/linux/skbuff.h

+1 −0
Original line number Diff line number Diff line
@@ -3449,6 +3449,7 @@ 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);

int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse);

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

			     gfp_t gfp);

net/core/skbuff.c

+33 −0
Original line number Diff line number Diff line
@@ -5531,6 +5531,39 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto) 
}

EXPORT_SYMBOL_GPL(skb_mpls_pop);



/**

 * skb_mpls_update_lse() - modify outermost MPLS header and update csum

 *

 * @skb: buffer

 * @mpls_lse: new MPLS label stack entry to update to

 *

 * Expects skb->data at mac header.

 *

 * Returns 0 on success, -errno otherwise.

 */

int skb_mpls_update_lse(struct sk_buff *skb, __be32 mpls_lse)

{

	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;



	if (skb->ip_summed == CHECKSUM_COMPLETE) {

		__be32 diff[] = { ~mpls_hdr(skb)->label_stack_entry, mpls_lse };



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

	}



	mpls_hdr(skb)->label_stack_entry = mpls_lse;



	return 0;

}

EXPORT_SYMBOL_GPL(skb_mpls_update_lse);



/**

 * alloc_skb_with_frags - allocate skb with page frags

 *

net/openvswitch/actions.c

+3 −10
Original line number Diff line number Diff line
@@ -193,19 +193,12 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key, 
	__be32 lse;

	int err;



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

	if (unlikely(err))

		return err;



	stack = mpls_hdr(skb);

	lse = OVS_MASKED(stack->label_stack_entry, *mpls_lse, *mask);

	if (skb->ip_summed == CHECKSUM_COMPLETE) {

		__be32 diff[] = { ~(stack->label_stack_entry), lse };



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

	}

	err = skb_mpls_update_lse(skb, lse);

	if (err)

		return err;



	stack->label_stack_entry = lse;

	flow_key->mpls.top_lse = lse;

	return 0;

}