From 91820da6ae85904d95ed53bf3a83f9ec44a6b80a Mon Sep 17 00:00:00 2001 From: Jiri Benc Date: Thu, 10 Nov 2016 16:28:23 +0100 Subject: [PATCH] openvswitch: add Ethernet push and pop actions 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 Signed-off-by: Simon Horman Signed-off-by: Jiri Benc Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- include/uapi/linux/openvswitch.h | 15 ++++++++++ net/openvswitch/actions.c | 49 ++++++++++++++++++++++++++++++++ net/openvswitch/flow_netlink.c | 18 ++++++++++++ 3 files changed, 82 insertions(+) diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index 59ed3992c760..375d812fea36 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h @@ -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. */ diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 064cbcb7b0c5..514f7bcf7c63 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -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)) { diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c index c3d0cc4321c3..d19044f2b1f4 100644 --- a/net/openvswitch/flow_netlink.c +++ b/net/openvswitch/flow_netlink.c @@ -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; -- 2.30.2