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openvswitch: add Ethernet push and pop actions

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It's not allowed to push Ethernet header in front of another Ethernet
header.

It's not allowed to pop Ethernet header if there's a vlan tag. This
preserves the invariant that L3 packet never has a vlan tag.

Based on previous versions by Lorand Jakab and Simon Horman.

Signed-off-by: Lorand Jakab <lojakab@cisco.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Benc 2016-11-10 16:28:23 +01:00 committed by David S. Miller
parent 0a6410fbde
commit 91820da6ae
3 changed files with 82 additions and 0 deletions
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15
include/uapi/linux/openvswitch.h
View File

@ -705,6 +705,15 @@ enum ovs_nat_attr {
#define OVS_NAT_ATTR_MAX (__OVS_NAT_ATTR_MAX - 1)
/*
* struct ovs_action_push_eth - %OVS_ACTION_ATTR_PUSH_ETH action argument.
* @addresses: Source and destination MAC addresses.
* @eth_type: Ethernet type
*/
struct ovs_action_push_eth {
struct ovs_key_ethernet addresses;
};
/**
* enum ovs_action_attr - Action types.
*
@ -738,6 +747,10 @@ enum ovs_nat_attr {
* is no MPLS label stack, as determined by ethertype, no action is taken.
* @OVS_ACTION_ATTR_CT: Track the connection. Populate the conntrack-related
* entries in the flow key.
* @OVS_ACTION_ATTR_PUSH_ETH: Push a new outermost Ethernet header onto the
* packet.
* @OVS_ACTION_ATTR_POP_ETH: Pop the outermost Ethernet header off the
* packet.
*
* Only a single header can be set with a single %OVS_ACTION_ATTR_SET. Not all
* fields within a header are modifiable, e.g. the IPv4 protocol and fragment
@ -765,6 +778,8 @@ enum ovs_action_attr {
* bits. */
OVS_ACTION_ATTR_CT, /* Nested OVS_CT_ATTR_* . */
OVS_ACTION_ATTR_TRUNC, /* u32 struct ovs_action_trunc. */
OVS_ACTION_ATTR_PUSH_ETH, /* struct ovs_action_push_eth. */
OVS_ACTION_ATTR_POP_ETH, /* No argument. */
__OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
* from userspace. */

49
net/openvswitch/actions.c
View File

@ -317,6 +317,47 @@ static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *flow_key,
return 0;
}
/* pop_eth does not support VLAN packets as this action is never called
* for them.
*/
static int pop_eth(struct sk_buff *skb, struct sw_flow_key *key)
{
skb_pull_rcsum(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);
/* safe right before invalidate_flow_key */
key->mac_proto = MAC_PROTO_NONE;
invalidate_flow_key(key);
return 0;
}
static int push_eth(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_action_push_eth *ethh)
{
struct ethhdr *hdr;
/* Add the new Ethernet header */
if (skb_cow_head(skb, ETH_HLEN) < 0)
return -ENOMEM;
skb_push(skb, ETH_HLEN);
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);
hdr = eth_hdr(skb);
ether_addr_copy(hdr->h_source, ethh->addresses.eth_src);
ether_addr_copy(hdr->h_dest, ethh->addresses.eth_dst);
hdr->h_proto = skb->protocol;
skb_postpush_rcsum(skb, hdr, ETH_HLEN);
/* safe right before invalidate_flow_key */
key->mac_proto = MAC_PROTO_ETHERNET;
invalidate_flow_key(key);
return 0;
}
static void update_ip_l4_checksum(struct sk_buff *skb, struct iphdr *nh,
__be32 addr, __be32 new_addr)
{
@ -1200,6 +1241,14 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
if (err)
return err == -EINPROGRESS ? 0 : err;
break;
case OVS_ACTION_ATTR_PUSH_ETH:
err = push_eth(skb, key, nla_data(a));
break;
case OVS_ACTION_ATTR_POP_ETH:
err = pop_eth(skb, key);
break;
}
if (unlikely(err)) {

18
net/openvswitch/flow_netlink.c
View File

@ -2383,6 +2383,8 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
[OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash),
[OVS_ACTION_ATTR_CT] = (u32)-1,
[OVS_ACTION_ATTR_TRUNC] = sizeof(struct ovs_action_trunc),
[OVS_ACTION_ATTR_PUSH_ETH] = sizeof(struct ovs_action_push_eth),
[OVS_ACTION_ATTR_POP_ETH] = 0,
};
const struct ovs_action_push_vlan *vlan;
int type = nla_type(a);
@ -2517,6 +2519,22 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
skip_copy = true;
break;
case OVS_ACTION_ATTR_PUSH_ETH:
/* Disallow pushing an Ethernet header if one
* is already present */
if (mac_proto != MAC_PROTO_NONE)
return -EINVAL;
mac_proto = MAC_PROTO_NONE;
break;
case OVS_ACTION_ATTR_POP_ETH:
if (mac_proto != MAC_PROTO_ETHERNET)
return -EINVAL;
if (vlan_tci & htons(VLAN_TAG_PRESENT))
return -EINVAL;
mac_proto = MAC_PROTO_ETHERNET;
break;
default:
OVS_NLERR(log, "Unknown Action type %d", type);
return -EINVAL;