ofp-util: Work on decoding OF1.1 flow_mods.

[openvswitch] / datapath / tunnel.h

/*
 * 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
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * 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
#define TNL_T_PROTO_CAPWAP      1

/* 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. */
#define TNL_F_PUBLIC (TNL_F_CSUM | TNL_F_TOS_INHERIT | TNL_F_TTL_INHERIT | \
                      TNL_F_DF_INHERIT | TNL_F_DF_DEFAULT | TNL_F_PMTUD | \
                      TNL_F_HDR_CACHE | TNL_F_IPSEC)

/**
 * 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;
#ifdef CONFIG_NET_NS
        struct net *net;
#endif
        __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 *);
};

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
/*
 * On these kernels we have a fast mechanism to tell if the ARP cache for a
 * particular destination has changed.
 */
#define HAVE_HH_SEQ
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
/*
 * On these kernels we have a fast mechanism to tell if the routing table
 * has changed.
 */
#define HAVE_RT_GENID
#endif
#if !defined(HAVE_HH_SEQ) || !defined(HAVE_RT_GENID)
/* If we can't detect all system changes directly we need to use a timeout. */
#define NEED_CACHE_TIMEOUT
#endif
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;
#endif

#ifdef NEED_CACHE_TIMEOUT
        /*
         * 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;
#endif

        /*
         * 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. */

#ifdef NEED_CACHE_TIMEOUT
        /*
         * 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;
#endif
};

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 */