text: /*
   * net/tipc/link.h: Include file for TIPC link code
   *
   * Copyright (c) 1995-2006, 2013-2014, Ericsson AB
   * Copyright (c) 2004-2005, 2010-2011, Wind River Systems
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the names of the copyright holders nor the names of its
   *    contributors may be used to endorse or promote products derived from
   *    this software without specific prior written permission.
   *
   * Alternatively, this software may be distributed under the terms of the
   * GNU General Public License ("GPL") version 2 as published by the Free
   * Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef _TIPC_LINK_H
  #define _TIPC_LINK_H
  
  #include <net/genetlink.h>
  #include "msg.h"
  #include "node.h"
  
  /* TIPC-specific error codes
  */
  #define ELINKCONG EAGAIN	/* link congestion <=> resource unavailable */
  
  /* Out-of-range value for link sequence numbers
   */
  #define INVALID_LINK_SEQ 0x10000
  
  /* Link FSM events:
   */
  enum {
  	LINK_ESTABLISH_EVT       = 0xec1ab1e,
  	LINK_PEER_RESET_EVT      = 0x9eed0e,
  	LINK_FAILURE_EVT         = 0xfa110e,
  	LINK_RESET_EVT           = 0x10ca1d0e,
  	LINK_FAILOVER_BEGIN_EVT  = 0xfa110bee,
  	LINK_FAILOVER_END_EVT    = 0xfa110ede,
  	LINK_SYNCH_BEGIN_EVT     = 0xc1ccbee,
  	LINK_SYNCH_END_EVT       = 0xc1ccede
  };
  
  /* Events returned from link at packet reception or at timeout
   */
  enum {
  	TIPC_LINK_UP_EVT       = 1,
  	TIPC_LINK_DOWN_EVT     = (1 << 1),
  	TIPC_LINK_SND_BC_ACK   = (1 << 2)
  };
  
  /* Starting value for maximum packet size negotiation on unicast links
   * (unless bearer MTU is less)
   */
  #define MAX_PKT_DEFAULT 1500
  
  struct tipc_stats {
  	u32 sent_info;		/* used in counting # sent packets */
  	u32 recv_info;		/* used in counting # recv'd packets */
  	u32 sent_states;
  	u32 recv_states;
  	u32 sent_probes;
  	u32 recv_probes;
  	u32 sent_nacks;
  	u32 recv_nacks;
  	u32 sent_acks;
  	u32 sent_bundled;
  	u32 sent_bundles;
  	u32 recv_bundled;
  	u32 recv_bundles;
  	u32 retransmitted;
  	u32 sent_fragmented;
  	u32 sent_fragments;
  	u32 recv_fragmented;
  	u32 recv_fragments;
  	u32 link_congs;		/* # port sends blocked by congestion */
  	u32 deferred_recv;
  	u32 duplicates;
  	u32 max_queue_sz;	/* send queue size high water mark */
  	u32 accu_queue_sz;	/* used for send queue size profiling */
  	u32 queue_sz_counts;	/* used for send queue size profiling */
  	u32 msg_length_counts;	/* used for message length profiling */
  	u32 msg_lengths_total;	/* used for message length profiling */
  	u32 msg_length_profile[7]; /* used for msg. length profiling */
  };
  
  /**
   * struct tipc_link - TIPC link data structure
   * @addr: network address of link's peer node
   * @name: link name character string
   * @media_addr: media address to use when sending messages over link
   * @timer: link timer
   * @net: pointer to namespace struct
   * @refcnt: reference counter for permanent references (owner node & timer)
   * @peer_session: link session # being used by peer end of link
   * @peer_bearer_id: bearer id used by link's peer endpoint
   * @bearer_id: local bearer id used by link
   * @tolerance: minimum link continuity loss needed to reset link [in ms]
   * @keepalive_intv: link keepalive timer interval
   * @abort_limit: # of unacknowledged continuity probes needed to reset link
   * @state: current state of link FSM
   * @peer_caps: bitmap describing capabilities of peer node
   * @silent_intv_cnt: # of timer intervals without any reception from peer
   * @proto_msg: template for control messages generated by link
   * @pmsg: convenience pointer to "proto_msg" field
   * @priority: current link priority
   * @net_plane: current link network plane ('A' through 'H')
   * @backlog_limit: backlog queue congestion thresholds (indexed by importance)
   * @exp_msg_count: # of tunnelled messages expected during link changeover
   * @reset_rcv_checkpt: seq # of last acknowledged message at time of link reset
   * @mtu: current maximum packet size for this link
   * @advertised_mtu: advertised own mtu when link is being established
   * @transmitq: queue for sent, non-acked messages
   * @backlogq: queue for messages waiting to be sent
   * @snt_nxt: next sequence number to use for outbound messages
   * @last_retransmitted: sequence number of most recently retransmitted message
   * @stale_count: # of identical retransmit requests made by peer
   * @ackers: # of peers that needs to ack each packet before it can be released
   * @acked: # last packet acked by a certain peer. Used for broadcast.
   * @rcv_nxt: next sequence number to expect for inbound messages
   * @deferred_queue: deferred queue saved OOS b'cast message received from node
   * @unacked_window: # of inbound messages rx'd without ack'ing back to peer
   * @inputq: buffer queue for messages to be delivered upwards
   * @namedq: buffer queue for name table messages to be delivered upwards
   * @next_out: ptr to first unsent outbound message in queue
   * @wakeupq: linked list of wakeup msgs waiting for link congestion to abate
   * @long_msg_seq_no: next identifier to use for outbound fragmented messages
   * @reasm_buf: head of partially reassembled inbound message fragments
   * @bc_rcvr: marks that this is a broadcast receiver link
   * @stats: collects statistics regarding link activity
   */
  struct tipc_link {
  	u32 addr;
  	char name[TIPC_MAX_LINK_NAME];
  	struct tipc_media_addr *media_addr;
  	struct net *net;
  
  	/* Management and link supervision data */
  	u32 peer_session;
  	u32 peer_bearer_id;
  	u32 bearer_id;
  	u32 tolerance;
  	unsigned long keepalive_intv;
  	u32 abort_limit;
  	u32 state;
  	u16 peer_caps;
  	bool active;
  	u32 silent_intv_cnt;
  	struct {
  		unchar hdr[INT_H_SIZE];
  		unchar body[TIPC_MAX_IF_NAME];
  	} proto_msg;
  	struct tipc_msg *pmsg;
  	u32 priority;
  	char net_plane;
  
  	/* Failover/synch */
  	u16 drop_point;
  	struct sk_buff *failover_reasm_skb;
  
  	/* Max packet negotiation */
  	u16 mtu;
  	u16 advertised_mtu;
  
  	/* Sending */
  	struct sk_buff_head transmq;
  	struct sk_buff_head backlogq;
  	struct {
  		u16 len;
  		u16 limit;
  	} backlog[5];
  	u16 snd_nxt;
  	u16 last_retransm;
  	u16 window;
  	u32 stale_count;
  
  	/* Reception */
  	u16 rcv_nxt;
  	u32 rcv_unacked;
  	struct sk_buff_head deferdq;
  	struct sk_buff_head *inputq;
  	struct sk_buff_head *namedq;
  
  	/* Congestion handling */
  	struct sk_buff_head wakeupq;
  
  	/* Fragmentation/reassembly */
  	struct sk_buff *reasm_buf;
  
  	/* Broadcast */
  	u16 ackers;
  	u16 acked;
  	struct tipc_link *bc_rcvlink;
  	struct tipc_link *bc_sndlink;
  	int nack_state;
  	bool bc_peer_is_up;
  
  	/* Statistics */
  	struct tipc_stats stats;
  };
  
  bool tipc_link_create(struct net *net, char *if_name, int bearer_id,
  		      int tolerance, char net_plane, u32 mtu, int priority,
  		      int window, u32 session, u32 ownnode, u32 peer,
  		      u16 peer_caps,
  		      struct tipc_link *bc_sndlink,
  		      struct tipc_link *bc_rcvlink,
  		      struct sk_buff_head *inputq,
  		      struct sk_buff_head *namedq,
  		      struct tipc_link **link);
  bool tipc_link_bc_create(struct net *net, u32 ownnode, u32 peer,
  			 int mtu, int window, u16 peer_caps,
  			 struct sk_buff_head *inputq,
  			 struct sk_buff_head *namedq,
  			 struct tipc_link *bc_sndlink,
  			 struct tipc_link **link);
  void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
  			   int mtyp, struct sk_buff_head *xmitq);
  void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
  int tipc_link_fsm_evt(struct tipc_link *l, int evt);
  void tipc_link_reset_fragments(struct tipc_link *l_ptr);
  bool tipc_link_is_up(struct tipc_link *l);
  bool tipc_link_peer_is_down(struct tipc_link *l);
  bool tipc_link_is_reset(struct tipc_link *l);
  bool tipc_link_is_establishing(struct tipc_link *l);
  bool tipc_link_is_synching(struct tipc_link *l);
  bool tipc_link_is_failingover(struct tipc_link *l);
  bool tipc_link_is_blocked(struct tipc_link *l);
  void tipc_link_set_active(struct tipc_link *l, bool active);
  void tipc_link_reset(struct tipc_link *l_ptr);
  int tipc_link_xmit(struct tipc_link *link,	struct sk_buff_head *list,
  		   struct sk_buff_head *xmitq);
  void tipc_link_set_queue_limits(struct tipc_link *l, u32 window);
  
  int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb);
  int tipc_nl_link_get(struct sk_buff *skb, struct genl_info *info);
  int tipc_nl_link_set(struct sk_buff *skb, struct genl_info *info);
  int tipc_nl_link_reset_stats(struct sk_buff *skb, struct genl_info *info);
  int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[]);
  int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq);
  int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
  		  struct sk_buff_head *xmitq);
  int tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
  void tipc_link_add_bc_peer(struct tipc_link *snd_l,
  			   struct tipc_link *uc_l,
  			   struct sk_buff_head *xmitq);
  void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
  			      struct tipc_link *rcv_l,
  			      struct sk_buff_head *xmitq);
  int tipc_link_bc_peers(struct tipc_link *l);
  void tipc_link_set_mtu(struct tipc_link *l, int mtu);
  int tipc_link_mtu(struct tipc_link *l);
  void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
  			  struct sk_buff_head *xmitq);
  void tipc_link_build_bc_sync_msg(struct tipc_link *l,
  				 struct sk_buff_head *xmitq);
  void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr);
  void tipc_link_bc_sync_rcv(struct tipc_link *l,   struct tipc_msg *hdr,
  			   struct sk_buff_head *xmitq);
  int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
  			  struct sk_buff_head *xmitq);
  #endif
  