/*
   * 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 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 sync;
  };
  
  /**
   * 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;
  
  #ifdef CONFIG_NET_NS
  	/* Network namespace ref. */
  	struct net *net;
  #endif
  
  	u32 user_features;
  };
  
  /**
   * struct ovs_skb_cb - OVS data in skb CB
   * @flow: The flow associated with this packet.  May be %NULL if no flow.
   * @pkt_key: The flow information extracted from the packet.  Must be nonnull.
   * @tun_key: Key for the tunnel that encapsulated this packet. NULL if the
   * packet is not being tunneled.
   */
  struct ovs_skb_cb {
  	struct sw_flow		*flow;
  	struct sw_flow_key	*pkt_key;
  	struct ovs_key_ipv4_tunnel  *tun_key;
  };
  #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_*.
   * @key: Becomes %OVS_PACKET_ATTR_KEY.  Must be nonnull.
   * @userdata: If nonnull, its variable-length value is passed to userspace as
   * %OVS_PACKET_ATTR_USERDATA.
   * @pid: Netlink PID to which packet should be sent.  If @pid is 0 then no
   * packet is sent and the packet is accounted in the datapath's @n_lost
   * counter.
   */
  struct dp_upcall_info {
  	u8 cmd;
  	const struct sw_flow_key *key;
  	const struct nlattr *userdata;
  	u32 portid;
  };
  
  /**
   * 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(unlikely(!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(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_received_packet(struct vport *, struct sk_buff *);
  void ovs_dp_detach_port(struct vport *);
  int ovs_dp_upcall(struct datapath *, struct sk_buff *,
  		  const struct dp_upcall_info *);
  
  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);
  void ovs_dp_notify_wq(struct work_struct *work);
  
  #define OVS_NLERR(fmt, ...) \
  	pr_info_once("netlink: " fmt, ##__VA_ARGS__)
  
  #endif /* datapath.h */