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* Copyright (c) 2007-2012 Nicira, Inc.
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA
#ifndef TUNNEL_H
#define TUNNEL_H 1
#include <linux/version.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include "flow.h"
#include "openvswitch/tunnel.h"
#include "vport.h"
* The absolute minimum fragment size. Note that there are many other
* definitions of the minimum MTU.
#define IP_MIN_MTU 68
* One of these goes in struct tnl_ops and in tnl_find_port().
* These values are in the same namespace as other TNL_T_* values, so
* only the least significant 10 bits are available to define protocol
* identifiers.
#define TNL_T_PROTO_GRE 0
/* These flags are only needed when calling tnl_find_port(). */
#define TNL_T_KEY_EXACT (1 << 10)
#define TNL_T_KEY_MATCH (1 << 11)
/* Private flags not exposed to userspace in this form. */
#define TNL_F_IN_KEY_MATCH (1 << 16) /* Store the key in tun_id to
* match in flow table. */
#define TNL_F_OUT_KEY_ACTION (1 << 17) /* Get the key from a SET_TUNNEL
* action. */
/* All public tunnel flags. */
* struct port_lookup_key - Tunnel port key, used as hash table key.
* @in_key: Key to match on input, 0 for wildcard.
* @net: Network namespace of the port.
* @saddr: IPv4 source address to match, 0 to accept any source address.
* @daddr: IPv4 destination of tunnel.
* @tunnel_type: Set of TNL_T_* flags that define lookup.
struct port_lookup_key {
__be64 in_key;
struct net *net;
__be32 saddr;
__be32 daddr;
u32 tunnel_type;
#define PORT_KEY_LEN (offsetof(struct port_lookup_key, tunnel_type) + \
FIELD_SIZEOF(struct port_lookup_key, tunnel_type))
static inline struct net *port_key_get_net(const struct port_lookup_key *key)
return read_pnet(&key->net);
static inline void port_key_set_net(struct port_lookup_key *key, struct net *net)
write_pnet(&key->net, net);
* struct tnl_mutable_config - modifiable configuration for a tunnel.
* @key: Used as key for tunnel port. Configured via OVS_TUNNEL_ATTR_*
* attributes.
* @rcu: RCU callback head for deferred destruction.
* @seq: Sequence number for distinguishing configuration versions.
* @tunnel_hlen: Tunnel header length.
* @eth_addr: Source address for packets generated by tunnel itself
* (e.g. ICMP fragmentation needed messages).
* @out_key: Key to use on output, 0 if this tunnel has no fixed output key.
* @flags: TNL_F_* flags.
* @tos: IPv4 TOS value to use for tunnel, 0 if no fixed TOS.
* @ttl: IPv4 TTL value to use for tunnel, 0 if no fixed TTL.
struct tnl_mutable_config {
struct port_lookup_key key;
struct rcu_head rcu;
unsigned seq;
unsigned tunnel_hlen;
unsigned char eth_addr[ETH_ALEN];
/* Configured via OVS_TUNNEL_ATTR_* attributes. */
__be64 out_key;
u32 flags;
u8 tos;
u8 ttl;
/* Multicast configuration. */
int mlink;
struct tnl_ops {
u32 tunnel_type; /* Put the TNL_T_PROTO_* type in here. */
u8 ipproto; /* The IP protocol for the tunnel. */
* Returns the length of the tunnel header that will be added in
* build_header() (i.e. excludes the IP header). Returns a negative
* error code if the configuration is invalid.
int (*hdr_len)(const struct tnl_mutable_config *);
* Builds the static portion of the tunnel header, which is stored in
* the header cache. In general the performance of this function is
* not too important as we try to only call it when building the cache
* so it is preferable to shift as much work as possible here. However,
* in some circumstances caching is disabled and this function will be
* called for every packet, so try not to make it too slow.
void (*build_header)(const struct vport *,
const struct tnl_mutable_config *, void *header);
* Updates the cached header of a packet to match the actual packet
* data. Typical things that might need to be updated are length,
* checksum, etc. The IP header will have already been updated and this
* is the final step before transmission. Returns a linked list of
* completed SKBs (multiple packets may be generated in the event
* of fragmentation).
struct sk_buff *(*update_header)(const struct vport *,
const struct tnl_mutable_config *,
struct dst_entry *, struct sk_buff *);
* On these kernels we have a fast mechanism to tell if the ARP cache for a
* particular destination has changed.
#define HAVE_HH_SEQ
* On these kernels we have a fast mechanism to tell if the routing table
* has changed.
#if !defined(HAVE_HH_SEQ) || !defined(HAVE_RT_GENID)
/* If we can't detect all system changes directly we need to use a timeout. */
struct tnl_cache {
struct rcu_head rcu;
int len; /* Length of data to be memcpy'd from cache. */
int hh_len; /* Hardware hdr length, cached from hh_cache. */
/* Sequence number of mutable->seq from which this cache was
* generated. */
unsigned mutable_seq;
#ifdef HAVE_HH_SEQ
* The sequence number from the seqlock protecting the hardware header
* cache (in the ARP cache). Since every write increments the counter
* this gives us an easy way to tell if it has changed.
unsigned hh_seq;
* If we don't have direct mechanisms to detect all important changes in
* the system fall back to an expiration time. This expiration time
* can be relatively short since at high rates there will be millions of
* packets per second, so we'll still get plenty of benefit from the
* cache. Note that if something changes we may blackhole packets
* until the expiration time (depending on what changed and the kernel
* version we may be able to detect the change sooner). Expiration is
* expressed as a time in jiffies.
unsigned long expiration;
* The routing table entry that is the result of looking up the tunnel
* endpoints. It also contains a sequence number (called a generation
* ID) that can be compared to a global sequence to tell if the routing
* table has changed (and therefore there is a potential that this
* cached route has been invalidated).
struct rtable *rt;
* If the output device for tunnel traffic is an OVS internal device,
* the flow of that datapath. Since all tunnel traffic will have the
* same headers this allows us to cache the flow lookup. NULL if the
* output device is not OVS or if there is no flow installed.
struct sw_flow *flow;
/* The cached header follows after padding for alignment. */
struct tnl_vport {
struct rcu_head rcu;
struct hlist_node hash_node;
char name[IFNAMSIZ];
const struct tnl_ops *tnl_ops;
struct tnl_mutable_config __rcu *mutable;
* ID of last fragment sent (for tunnel protocols with direct support
* fragmentation). If the protocol relies on IP fragmentation then
* this is not needed.
atomic_t frag_id;
spinlock_t cache_lock;
struct tnl_cache __rcu *cache; /* Protected by RCU/cache_lock. */
* If we must rely on expiration time to invalidate the cache, this is
* the interval. It is randomized within a range (defined by
* MAX_CACHE_EXP in tunnel.c) to avoid synchronized expirations caused
* by creation of a large number of tunnels at a one time.
unsigned long cache_exp_interval;
struct vport *ovs_tnl_create(const struct vport_parms *, const struct vport_ops *,
const struct tnl_ops *);
void ovs_tnl_destroy(struct vport *);
int ovs_tnl_set_options(struct vport *, struct nlattr *);
int ovs_tnl_get_options(const struct vport *, struct sk_buff *);
int ovs_tnl_set_addr(struct vport *vport, const unsigned char *addr);
const char *ovs_tnl_get_name(const struct vport *vport);
const unsigned char *ovs_tnl_get_addr(const struct vport *vport);
int ovs_tnl_send(struct vport *vport, struct sk_buff *skb);
void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb, u8 tos);
struct vport *ovs_tnl_find_port(struct net *net, __be32 saddr, __be32 daddr,
__be64 key, int tunnel_type,
const struct tnl_mutable_config **mutable);
bool ovs_tnl_frag_needed(struct vport *vport,
const struct tnl_mutable_config *mutable,
struct sk_buff *skb, unsigned int mtu, __be64 flow_key);
void ovs_tnl_free_linked_skbs(struct sk_buff *skb);
int ovs_tnl_init(void);
void ovs_tnl_exit(void);
static inline struct tnl_vport *tnl_vport_priv(const struct vport *vport)
return vport_priv(vport);
#endif /* tunnel.h */
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