text: /*
   * IS-IS Rout(e)ing protocol - isis_adjacency.h
   *                             IS-IS adjacency handling
   *
   * Copyright (C) 2001,2002   Sampo Saaristo
   *                           Tampere University of Technology
   *                           Institute of Communications Engineering
   *
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public Licenseas published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   * 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; see the file COPYING; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #ifndef _ZEBRA_ISIS_ADJACENCY_H
  #define _ZEBRA_ISIS_ADJACENCY_H
  
  #include "isisd/isis_tlvs.h"
  
  DECLARE_MTYPE(ISIS_ADJACENCY_INFO);
  
  enum isis_adj_usage {
  	ISIS_ADJ_NONE,
  	ISIS_ADJ_LEVEL1,
  	ISIS_ADJ_LEVEL2,
  	ISIS_ADJ_LEVEL1AND2
  };
  
  enum isis_system_type {
  	ISIS_SYSTYPE_UNKNOWN,
  	ISIS_SYSTYPE_ES,
  	ISIS_SYSTYPE_IS,
  	ISIS_SYSTYPE_L1_IS,
  	ISIS_SYSTYPE_L2_IS
  };
  
  enum isis_adj_state {
  	ISIS_ADJ_UNKNOWN,
  	ISIS_ADJ_INITIALIZING,
  	ISIS_ADJ_UP,
  	ISIS_ADJ_DOWN
  };
  
  /*
   * we use the following codes to give an indication _why_
   * a specific adjacency is up or down
   */
  enum isis_adj_updown_reason {
  	ISIS_ADJ_REASON_SEENSELF,
  	ISIS_ADJ_REASON_AREA_MISMATCH,
  	ISIS_ADJ_REASON_HOLDTIMER_EXPIRED,
  	ISIS_ADJ_REASON_AUTH_FAILED,
  	ISIS_ADJ_REASON_CHECKSUM_FAILED
  };
  
  #define DIS_RECORDS 8	/* keep the last 8 DIS state changes on record */
  
  struct isis_dis_record {
  	int dis;		/* is our neighbor the DIS ? */
  	time_t last_dis_change; /* timestamp for last dis change */
  };
  
  struct bfd_session;
  struct isis_area;
  
  struct isis_adjacency {
  	uint8_t snpa[ETH_ALEN];		    /* NeighbourSNPAAddress */
  	uint8_t sysid[ISIS_SYS_ID_LEN];     /* neighbourSystemIdentifier */
  	uint8_t lanid[ISIS_SYS_ID_LEN + 1]; /* LAN id on bcast circuits */
  	int dischanges[ISIS_LEVELS];       /* how many DIS changes ? */
  	/* an array of N levels for M records */
  	struct isis_dis_record dis_record[DIS_RECORDS * ISIS_LEVELS];
  	enum isis_adj_state adj_state;    /* adjacencyState */
  	enum isis_adj_usage adj_usage;    /* adjacencyUsage */
  	struct area_addr *area_addresses; /* areaAdressesOfNeighbour */
  	unsigned int area_address_count;
  	struct nlpids nlpids; /* protocols spoken ... */
  	struct in_addr *ipv4_addresses;
  	unsigned int ipv4_address_count;
  	struct in_addr router_address;
  	struct in6_addr *ipv6_addresses;
  	unsigned int ipv6_address_count;
  	struct in6_addr router_address6;
  	uint8_t prio[ISIS_LEVELS];      /* priorityOfNeighbour for DIS */
  	int circuit_t;			/* from hello PDU hdr */
  	int level;			/* level (1 or 2) */
  	enum isis_system_type sys_type; /* neighbourSystemType */
  	uint16_t hold_time;		/* entryRemainingTime */
  	uint32_t last_upd;
  	uint32_t last_flap; /* last time the adj flapped */
  	enum isis_threeway_state threeway_state;
  	uint32_t ext_circuit_id;
  	int flaps;		      /* number of adjacency flaps  */
  	struct thread *t_expire;      /* expire after hold_time  */
  	struct isis_circuit *circuit; /* back pointer */
  	uint16_t *mt_set;      /* Topologies this adjacency is valid for */
  	unsigned int mt_count; /* Number of entries in mt_set */
  	struct bfd_session_params *bfd_session;
  	struct list *adj_sids; /* Segment Routing Adj-SIDs. */
  	uint32_t snmp_idx;
  	struct listnode *snmp_list_node;
  };
  
  struct isis_threeway_adj;
  
  struct isis_adjacency *isis_adj_lookup(const uint8_t *sysid,
  				       struct list *adjdb);
  struct isis_adjacency *isis_adj_lookup_snpa(const uint8_t *ssnpa,
  					    struct list *adjdb);
  struct isis_adjacency *isis_adj_find(const struct isis_area *area, int level,
  				     const uint8_t *sysid);
  struct isis_adjacency *isis_new_adj(const uint8_t *id, const uint8_t *snpa,
  				    int level, struct isis_circuit *circuit);
  void isis_delete_adj(void *adj);
  void isis_adj_process_threeway(struct isis_adjacency *adj,
  			       struct isis_threeway_adj *tw_adj,
  			       enum isis_adj_usage adj_usage);
  DECLARE_HOOK(isis_adj_state_change_hook, (struct isis_adjacency *adj), (adj));
  DECLARE_HOOK(isis_adj_ip_enabled_hook,
  	     (struct isis_adjacency *adj, int family), (adj, family));
  DECLARE_HOOK(isis_adj_ip_disabled_hook,
  	     (struct isis_adjacency *adj, int family), (adj, family));
  void isis_log_adj_change(struct isis_adjacency *adj,
  			 enum isis_adj_state old_state,
  			 enum isis_adj_state new_state, const char *reason);
  void isis_adj_state_change(struct isis_adjacency **adj,
  			   enum isis_adj_state state, const char *reason);
  void isis_adj_print(struct isis_adjacency *adj);
  const char *isis_adj_yang_state(enum isis_adj_state state);
  int isis_adj_expire(struct thread *thread);
  void isis_adj_print_vty(struct isis_adjacency *adj, struct vty *vty,
  			char detail);
  void isis_adj_build_neigh_list(struct list *adjdb, struct list *list);
  void isis_adj_build_up_list(struct list *adjdb, struct list *list);
  int isis_adj_usage2levels(enum isis_adj_usage usage);
  int isis_bfd_startup_timer(struct thread *thread);
  const char *isis_adj_name(const struct isis_adjacency *adj);
  
  #endif /* ISIS_ADJACENCY_H */
  