/*
 * Copyright (c) 2007-2014 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 DATAPATH_H
#define DATAPATH_H 1

#include <asm/page.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/u64_stats_sync.h>

#include "flow.h"
#include "flow_table.h"
#include "vport.h"

#define DP_MAX_PORTS           USHRT_MAX
#define DP_VPORT_HASH_BUCKETS  1024

#define SAMPLE_ACTION_DEPTH 3

/**
 * struct dp_stats_percpu - per-cpu packet processing statistics for a given
 * datapath.
 * @n_hit: Number of received packets for which a matching flow was found in
 * the flow table.
 * @n_miss: Number of received packets that had no matching flow in the flow
 * table.  The sum of @n_hit and @n_miss is the number of packets that have
 * been received by the datapath.
 * @n_lost: Number of received packets that had no matching flow in the flow
 * table that could not be sent to userspace (normally due to an overflow in
 * one of the datapath's queues).
 * @n_mask_hit: Number of masks looked up for flow match.
 *   @n_mask_hit / (@n_hit + @n_missed)  will be the average masks looked
 *   up per packet.
 */
struct dp_stats_percpu {
        u64 n_hit;
        u64 n_missed;
        u64 n_lost;
        u64 n_mask_hit;
        struct u64_stats_sync syncp;
};

/**
 * struct datapath - datapath for flow-based packet switching
 * @rcu: RCU callback head for deferred destruction.
 * @list_node: Element in global 'dps' list.
 * @table: flow table.
 * @ports: Hash table for ports.  %OVSP_LOCAL port always exists.  Protected by
 * ovs_mutex and RCU.
 * @stats_percpu: Per-CPU datapath statistics.
 * @net: Reference to net namespace.
 *
 * Context: See the comment on locking at the top of datapath.c for additional
 * locking information.
 */
struct datapath {
        struct rcu_head rcu;
        struct list_head list_node;

        /* Flow table. */
        struct flow_table table;

        /* Switch ports. */
        struct hlist_head *ports;

        /* Stats. */
        struct dp_stats_percpu __percpu *stats_percpu;

        /* Network namespace ref. */
        possible_net_t net;

        u32 user_features;
};

/**
 * struct ovs_skb_cb - OVS data in skb CB
 * @egress_tun_key: Tunnel information about this packet on egress path.
 * NULL if the packet is not being tunneled.
 * @input_vport: The original vport packet came in on. This value is cached
 * when a packet is received by OVS.
 */
struct ovs_skb_cb {
        struct ovs_tunnel_info  *egress_tun_info;
        struct vport            *input_vport;
};
#define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)

/**
 * struct dp_upcall - metadata to include with a packet to send to userspace
 * @cmd: One of %OVS_PACKET_CMD_*.
 * @userdata: If nonnull, its variable-length value is passed to userspace as
 * %OVS_PACKET_ATTR_USERDATA.
 * @portid: Netlink portid to which packet should be sent.  If @portid is 0
 * then no packet is sent and the packet is accounted in the datapath's @n_lost
 * counter.
 * @egress_tun_info: If nonnull, becomes %OVS_PACKET_ATTR_EGRESS_TUN_KEY.
 */
struct dp_upcall_info {
        const struct ovs_tunnel_info *egress_tun_info;
        const struct nlattr *userdata;
        const struct nlattr *actions;
        int actions_len;
        u32 portid;
        u8 cmd;
};

/**
 * struct ovs_net - Per net-namespace data for ovs.
 * @dps: List of datapaths to enable dumping them all out.
 * Protected by genl_mutex.
 */
struct ovs_net {
        struct list_head dps;
        struct work_struct dp_notify_work;
        struct vport_net vport_net;
};

extern int ovs_net_id;
void ovs_lock(void);
void ovs_unlock(void);

#ifdef CONFIG_LOCKDEP
int lockdep_ovsl_is_held(void);
#else
#define lockdep_ovsl_is_held()  1
#endif

#define ASSERT_OVSL()           WARN_ON(!lockdep_ovsl_is_held())
#define ovsl_dereference(p)                                     \
        rcu_dereference_protected(p, lockdep_ovsl_is_held())
#define rcu_dereference_ovsl(p)                                 \
        rcu_dereference_check(p, lockdep_ovsl_is_held())

static inline struct net *ovs_dp_get_net(const struct datapath *dp)
{
        return read_pnet(&dp->net);
}

static inline void ovs_dp_set_net(struct datapath *dp, struct net *net)
{
        write_pnet(&dp->net, net);
}

struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no);

static inline struct vport *ovs_vport_rcu(const struct datapath *dp, int port_no)
{
        WARN_ON_ONCE(!rcu_read_lock_held());
        return ovs_lookup_vport(dp, port_no);
}

static inline struct vport *ovs_vport_ovsl_rcu(const struct datapath *dp, int port_no)
{
        WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
        return ovs_lookup_vport(dp, port_no);
}

static inline struct vport *ovs_vport_ovsl(const struct datapath *dp, int port_no)
{
        ASSERT_OVSL();
        return ovs_lookup_vport(dp, port_no);
}

extern struct notifier_block ovs_dp_device_notifier;
extern struct genl_family dp_vport_genl_family;

void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key);
void ovs_dp_detach_port(struct vport *);
int ovs_dp_upcall(struct datapath *, struct sk_buff *,
                  const struct sw_flow_key *, const struct dp_upcall_info *);

const char *ovs_dp_name(const struct datapath *dp);
struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq,
                                         u8 cmd);

int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
                        const struct sw_flow_actions *, struct sw_flow_key *);

void ovs_dp_notify_wq(struct work_struct *work);

int action_fifos_init(void);
void action_fifos_exit(void);

#define OVS_NLERR(logging_allowed, fmt, ...)                    \
do {                                                            \
        if (logging_allowed && net_ratelimit())                 \
                pr_info("netlink: " fmt "\n", ##__VA_ARGS__);   \
} while (0)
#endif /* datapath.h */