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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: 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 15:01:54 +01:00 committed by David S. Miller
parent af144a9834
commit 8822e270d6
3 changed files with 69 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/skbuff.h
View File

@ -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);

64
net/core/skbuff.c
View File

@ -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
*

31
net/openvswitch/actions.c
View File

@ -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;
int err;
/* 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);
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;