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: John Hurley <john.hurley@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Hurley 2019-07-07 15:01:56 +01:00 committed by David S. Miller
parent ed246cee09
commit d27cf5c59a
3 changed files with 37 additions and 10 deletions

View File

@ -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);

View File

@ -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
*

View File

@ -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 };
err = skb_mpls_update_lse(skb, lse);
if (err)
return err;
skb->csum = csum_partial((char *)diff, sizeof(diff), skb->csum);
}
stack->label_stack_entry = lse;
flow_key->mpls.top_lse = lse;
return 0;
}