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Commit 8822e270 authored by John Hurley's avatar John Hurley Committed by David S. Miller
Browse files

net: core: move push MPLS functionality from OvS to core helper 



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

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 af144a98

include/linux/skbuff.h

+1 −0
Original line number Diff line number Diff line
@@ -3447,6 +3447,7 @@ int skb_ensure_writable(struct sk_buff *skb, int write_len); 
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);

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

			     gfp_t gfp);

net/core/skbuff.c

+64 −0
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ 
#include <net/checksum.h>

#include <net/ip6_checksum.h>

#include <net/xfrm.h>

#include <net/mpls.h>



#include <linux/uaccess.h>

#include <trace/events/skb.h>
@@ -5425,6 +5426,69 @@ int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci) 
}

EXPORT_SYMBOL(skb_vlan_push);



/* Update the ethertype of hdr and the skb csum value if required. */

static void skb_mod_eth_type(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;

}



/**

 * skb_mpls_push() - push a new MPLS header after the mac header

 *

 * @skb: buffer

 * @mpls_lse: MPLS label stack entry to push

 * @mpls_proto: ethertype of the new MPLS header (expects 0x8847 or 0x8848)

 *

 * Expects skb->data at mac header.

 *

 * Returns 0 on success, -errno otherwise.

 */

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

{

	struct mpls_shim_hdr *lse;

	int err;



	if (unlikely(!eth_p_mpls(mpls_proto)))

		return -EINVAL;



	/* Networking stack does not allow simultaneous Tunnel and MPLS GSO. */

	if (skb->encapsulation)

		return -EINVAL;



	err = skb_cow_head(skb, MPLS_HLEN);

	if (unlikely(err))

		return err;



	if (!skb->inner_protocol) {

		skb_set_inner_network_header(skb, skb->mac_len);

		skb_set_inner_protocol(skb, skb->protocol);

	}



	skb_push(skb, MPLS_HLEN);

	memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),

		skb->mac_len);

	skb_reset_mac_header(skb);

	skb_set_network_header(skb, skb->mac_len);



	lse = mpls_hdr(skb);

	lse->label_stack_entry = mpls_lse;

	skb_postpush_rcsum(skb, lse, MPLS_HLEN);



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

		skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto);

	skb->protocol = mpls_proto;



	return 0;

}

EXPORT_SYMBOL_GPL(skb_mpls_push);



/**

 * alloc_skb_with_frags - allocate skb with page frags

 *

net/openvswitch/actions.c

+4 −27
Original line number Diff line number Diff line
@@ -175,34 +175,11 @@ static void update_ethertype(struct sk_buff *skb, struct ethhdr *hdr, 
static int push_mpls(struct sk_buff *skb, struct sw_flow_key *key,

		     const struct ovs_action_push_mpls *mpls)

{

	struct mpls_shim_hdr *new_mpls_lse;



	/* Networking stack do not allow simultaneous Tunnel and MPLS GSO. */

	if (skb->encapsulation)

		return -ENOTSUPP;



	if (skb_cow_head(skb, MPLS_HLEN) < 0)

		return -ENOMEM;



	if (!skb->inner_protocol) {

		skb_set_inner_network_header(skb, skb->mac_len);

		skb_set_inner_protocol(skb, skb->protocol);

	}



	skb_push(skb, MPLS_HLEN);

	memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),

		skb->mac_len);

	skb_reset_mac_header(skb);

	skb_set_network_header(skb, skb->mac_len);



	new_mpls_lse = mpls_hdr(skb);

	new_mpls_lse->label_stack_entry = mpls->mpls_lse;



	skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);

	int err;



	if (ovs_key_mac_proto(key) == MAC_PROTO_ETHERNET)

		update_ethertype(skb, eth_hdr(skb), mpls->mpls_ethertype);

	skb->protocol = mpls->mpls_ethertype;

	err = skb_mpls_push(skb, mpls->mpls_lse, mpls->mpls_ethertype);

	if (err)

		return err;



	invalidate_flow_key(key);

	return 0;