nest/protocol.h

   1 /*
   2  *      BIRD Internet Routing Daemon -- Protocols
   3  *
   4  *      (c) 1998--2000 Martin Mares <mj@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #ifndef _BIRD_PROTOCOL_H_
  10 #define _BIRD_PROTOCOL_H_
  11
  12 #include "lib/lists.h"
  13 #include "lib/resource.h"
  14 #include "lib/event.h"
  15 #include "sysdep/unix/timer.h"
  16 #include "nest/route.h"
  17 #include "conf/conf.h"
  18
  19 struct iface;
  20 struct ifa;
  21 struct rtable;
  22 struct rte;
  23 struct neighbor;
  24 struct rta;
  25 struct network;
  26 struct proto_config;
  27 struct channel_limit;
  28 struct channel_config;
  29 struct config;
  30 struct proto;
  31 struct channel;
  32 struct ea_list;
  33 struct eattr;
  34 struct symbol;
  35
  36
  37 /*
  38  *      Routing Protocol
  39  */
  40
  41 struct protocol {
  42   node n;
  43   char *name;
  44   char *template;                       /* Template for automatic generation of names */
  45   int name_counter;                     /* Counter for automatic name generation */
  46   int attr_class;                       /* Attribute class known to this protocol */
  47   uint preference;                      /* Default protocol preference */
  48   uint channel_mask;                    /* Mask of accepted channel types (NB_*) */
  49   uint proto_size;                      /* Size of protocol data structure */
  50   uint config_size;                     /* Size of protocol config data structure */
  51
  52   void (*preconfig)(struct protocol *, struct config *);        /* Just before configuring */
  53   void (*postconfig)(struct proto_config *);                    /* After configuring each instance */
  54   struct proto * (*init)(struct proto_config *);                /* Create new instance */
  55   int (*reconfigure)(struct proto *, struct proto_config *);    /* Try to reconfigure instance, returns success */
  56   void (*dump)(struct proto *);                 /* Debugging dump */
  57   void (*dump_attrs)(struct rte *);             /* Dump protocol-dependent attributes */
  58   int (*start)(struct proto *);                 /* Start the instance */
  59   int (*shutdown)(struct proto *);              /* Stop the instance */
  60   void (*cleanup)(struct proto *);              /* Called after shutdown when protocol became hungry/down */
  61   void (*get_status)(struct proto *, byte *buf); /* Get instance status (for `show protocols' command) */
  62   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
  63   int (*get_attr)(struct eattr *, byte *buf, int buflen);       /* ASCIIfy dynamic attribute (returns GA_*) */
  64   void (*show_proto_info)(struct proto *);      /* Show protocol info (for `show protocols all' command) */
  65   void (*copy_config)(struct proto_config *, struct proto_config *);    /* Copy config from given protocol instance */
  66 };
  67
  68 void protos_build(void);
  69 void proto_build(struct protocol *);
  70 void protos_preconfig(struct config *);
  71 void protos_commit(struct config *new, struct config *old, int force_restart, int type);
  72 void protos_dump_all(void);
  73
  74 #define GA_UNKNOWN      0               /* Attribute not recognized */
  75 #define GA_NAME         1               /* Result = name */
  76 #define GA_FULL         2               /* Result = both name and value */
  77
  78 /*
  79  *      Known protocols
  80  */
  81
  82 extern struct protocol
  83   proto_device, proto_radv, proto_rip, proto_static,
  84   proto_ospf, proto_pipe, proto_bgp, proto_bfd;
  85
  86 /*
  87  *      Routing Protocol Instance
  88  */
  89
  90 struct proto_config {
  91   node n;
  92   struct config *global;                /* Global configuration data */
  93   struct protocol *protocol;            /* Protocol */
  94   struct proto *proto;                  /* Instance we've created */
  95   char *name;
  96   char *dsc;
  97   int class;                            /* SYM_PROTO or SYM_TEMPLATE */
  98   u8 net_type;                          /* Protocol network type (NET_*), 0 for undefined */
  99   u8 disabled;                          /* Protocol enabled/disabled by default */
 100   u32 debug, mrtdump;                   /* Debugging bitfields, both use D_* constants */
 101   u32 router_id;                        /* Protocol specific router ID */
 102
 103   list channels;                        /* List of channel configs (struct channel_config) */
 104
 105   /* Check proto_reconfigure() and proto_copy_config() after changing struct proto_config */
 106
 107   /* Protocol-specific data follow... */
 108 };
 109
 110 /* Protocol statistics */
 111 struct proto_stats {
 112   /* Import - from protocol to core */
 113   u32 imp_routes;               /* Number of routes successfully imported to the (adjacent) routing table */
 114   u32 filt_routes;              /* Number of routes rejected in import filter but kept in the routing table */
 115   u32 imp_updates_received;     /* Number of route updates received */
 116   u32 imp_updates_invalid;      /* Number of route updates rejected as invalid */
 117   u32 imp_updates_filtered;     /* Number of route updates rejected by filters */
 118   u32 imp_updates_ignored;      /* Number of route updates rejected as already in route table */
 119   u32 imp_updates_accepted;     /* Number of route updates accepted and imported */
 120   u32 imp_withdraws_received;   /* Number of route withdraws received */
 121   u32 imp_withdraws_invalid;    /* Number of route withdraws rejected as invalid */
 122   u32 imp_withdraws_ignored;    /* Number of route withdraws rejected as already not in route table */
 123   u32 imp_withdraws_accepted;   /* Number of route withdraws accepted and processed */
 124
 125   /* Export - from core to protocol */
 126   u32 exp_routes;               /* Number of routes successfully exported to the protocol */
 127   u32 exp_updates_received;     /* Number of route updates received */
 128   u32 exp_updates_rejected;     /* Number of route updates rejected by protocol */
 129   u32 exp_updates_filtered;     /* Number of route updates rejected by filters */
 130   u32 exp_updates_accepted;     /* Number of route updates accepted and exported */
 131   u32 exp_withdraws_received;   /* Number of route withdraws received */
 132   u32 exp_withdraws_accepted;   /* Number of route withdraws accepted and processed */
 133 };
 134
 135 struct proto {
 136   node n;                               /* Node in global proto_list */
 137   struct protocol *proto;               /* Protocol */
 138   struct proto_config *cf;              /* Configuration data */
 139   struct proto_config *cf_new;          /* Configuration we want to switch to after shutdown (NULL=delete) */
 140   pool *pool;                           /* Pool containing local objects */
 141   event *event;                         /* Protocol event */
 142
 143   list channels;                        /* List of channels to rtables (struct channel) */
 144   struct channel *main_channel;         /* Primary channel */
 145   struct rte_src *main_source;          /* Primary route source */
 146
 147   char *name;                           /* Name of this instance (== cf->name) */
 148   u32 debug;                            /* Debugging flags */
 149   u32 mrtdump;                          /* MRTDump flags */
 150   uint active_channels;                 /* Number of active channels */
 151   byte net_type;                        /* Protocol network type (NET_*), 0 for undefined */
 152   byte disabled;                        /* Manually disabled */
 153   byte proto_state;                     /* Protocol state machine (PS_*, see below) */
 154   byte active;                          /* From PS_START to cleanup after PS_STOP */
 155   byte do_start;                        /* Start actions are scheduled */
 156   byte do_stop;                         /* Stop actions are scheduled */
 157   byte reconfiguring;                   /* We're shutting down due to reconfiguration */
 158   byte gr_recovery;                     /* Protocol should participate in graceful restart recovery */
 159   byte down_sched;                      /* Shutdown is scheduled for later (PDS_*) */
 160   byte down_code;                       /* Reason for shutdown (PDC_* codes) */
 161   u32 hash_key;                         /* Random key used for hashing of neighbors */
 162   bird_clock_t last_state_change;       /* Time of last state transition */
 163   char *last_state_name_announced;      /* Last state name we've announced to the user */
 164
 165   /*
 166    *    General protocol hooks:
 167    *
 168    *       if_notify    Notify protocol about interface state changes.
 169    *       ifa_notify   Notify protocol about interface address changes.
 170    *       rt_notify    Notify protocol about routing table updates.
 171    *       neigh_notify Notify protocol about neighbor cache events.
 172    *       make_tmp_attrs  Construct ea_list from private attrs stored in rte.
 173    *       store_tmp_attrs Store private attrs back to the rte.
 174    *       import_control  Called as the first step of the route importing process.
 175    *                    It can construct a new rte, add private attributes and
 176    *                    decide whether the route shall be imported: 1=yes, -1=no,
 177    *                    0=process it through the import filter set by the user.
 178    *       reload_routes   Request channel to reload all its routes to the core
 179    *                    (using rte_update()). Returns: 0=reload cannot be done,
 180    *                    1= reload is scheduled and will happen (asynchronously).
 181    *       feed_begin   Notify channel about beginning of route feeding.
 182    *       feed_end     Notify channel about finish of route feeding.
 183    */
 184
 185   void (*if_notify)(struct proto *, unsigned flags, struct iface *i);
 186   void (*ifa_notify)(struct proto *, unsigned flags, struct ifa *a);
 187   void (*rt_notify)(struct proto *, struct channel *, struct network *net, struct rte *new, struct rte *old, struct ea_list *attrs);
 188   void (*neigh_notify)(struct neighbor *neigh);
 189   struct ea_list *(*make_tmp_attrs)(struct rte *rt, struct linpool *pool);
 190   void (*store_tmp_attrs)(struct rte *rt, struct ea_list *attrs);
 191   int (*import_control)(struct proto *, struct rte **rt, struct ea_list **attrs, struct linpool *pool);
 192   void (*reload_routes)(struct channel *);
 193   void (*feed_begin)(struct channel *, int initial);
 194   void (*feed_end)(struct channel *);
 195
 196   /*
 197    *    Routing entry hooks (called only for routes belonging to this protocol):
 198    *
 199    *       rte_recalculate Called at the beginning of the best route selection
 200    *       rte_better   Compare two rte's and decide which one is better (1=first, 0=second).
 201    *       rte_same     Compare two rte's and decide whether they are identical (1=yes, 0=no).
 202    *       rte_mergable Compare two rte's and decide whether they could be merged (1=yes, 0=no).
 203    *       rte_insert   Called whenever a rte is inserted to a routing table.
 204    *       rte_remove   Called whenever a rte is removed from the routing table.
 205    */
 206
 207   int (*rte_recalculate)(struct rtable *, struct network *, struct rte *, struct rte *, struct rte *);
 208   int (*rte_better)(struct rte *, struct rte *);
 209   int (*rte_same)(struct rte *, struct rte *);
 210   int (*rte_mergable)(struct rte *, struct rte *);
 211   void (*rte_insert)(struct network *, struct rte *);
 212   void (*rte_remove)(struct network *, struct rte *);
 213
 214   /* Hic sunt protocol-specific data */
 215 };
 216
 217 struct proto_spec {
 218   void *ptr;
 219   int patt;
 220 };
 221
 222
 223 #define PDS_DISABLE             1       /* Proto disable scheduled */
 224 #define PDS_RESTART             2       /* Proto restart scheduled */
 225
 226 #define PDC_CF_REMOVE           0x01    /* Removed in new config */
 227 #define PDC_CF_DISABLE          0x02    /* Disabled in new config */
 228 #define PDC_CF_RESTART          0x03    /* Restart due to reconfiguration */
 229 #define PDC_CMD_DISABLE         0x11    /* Result of disable command */
 230 #define PDC_CMD_RESTART         0x12    /* Result of restart command */
 231 #define PDC_CMD_SHUTDOWN        0x13    /* Result of global shutdown */
 232 #define PDC_RX_LIMIT_HIT        0x21    /* Route receive limit reached */
 233 #define PDC_IN_LIMIT_HIT        0x22    /* Route import limit reached */
 234 #define PDC_OUT_LIMIT_HIT       0x23    /* Route export limit reached */
 235
 236
 237 void *proto_new(struct proto_config *);
 238 void *proto_config_new(struct protocol *, int class);
 239 void proto_copy_config(struct proto_config *dest, struct proto_config *src);
 240
 241 void graceful_restart_recovery(void);
 242 void graceful_restart_init(void);
 243 void graceful_restart_show_status(void);
 244 void channel_graceful_restart_lock(struct channel *c);
 245 void channel_graceful_restart_unlock(struct channel *c);
 246
 247 #define DEFAULT_GR_WAIT 240
 248
 249 void channel_show_limit(struct channel_limit *l, const char *dsc);
 250 void channel_show_info(struct channel *c);
 251
 252 void proto_cmd_show(struct proto *, uint, int);
 253 void proto_cmd_disable(struct proto *, uint, int);
 254 void proto_cmd_enable(struct proto *, uint, int);
 255 void proto_cmd_restart(struct proto *, uint, int);
 256 void proto_cmd_reload(struct proto *, uint, int);
 257 void proto_cmd_debug(struct proto *, uint, int);
 258 void proto_cmd_mrtdump(struct proto *, uint, int);
 259
 260 void proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uint, int), int restricted, uint arg);
 261 struct proto *proto_get_named(struct symbol *, struct protocol *);
 262
 263 #define CMD_RELOAD      0
 264 #define CMD_RELOAD_IN   1
 265 #define CMD_RELOAD_OUT  2
 266
 267 static inline u32
 268 proto_get_router_id(struct proto_config *pc)
 269 {
 270   return pc->router_id ? pc->router_id : pc->global->router_id;
 271 }
 272
 273 /* Moved from route.h to avoid dependency conflicts */
 274 static inline void rte_update(struct proto *p, net *net, rte *new) { rte_update2(p->main_channel, net, new, p->main_source); }
 275
 276 extern list proto_list;
 277
 278 /*
 279  *  Each protocol instance runs two different state machines:
 280  *
 281  *  [P] The protocol machine: (implemented inside protocol)
 282  *
 283  *              DOWN    ---->    START
 284  *                ^                |
 285  *                |                V
 286  *              STOP    <----     UP
 287  *
 288  *      States: DOWN    Protocol is down and it's waiting for the core
 289  *                      requesting protocol start.
 290  *              START   Protocol is waiting for connection with the rest
 291  *                      of the network and it's not willing to accept
 292  *                      packets. When it connects, it goes to UP state.
 293  *              UP      Protocol is up and running. When the network
 294  *                      connection breaks down or the core requests
 295  *                      protocol to be terminated, it goes to STOP state.
 296  *              STOP    Protocol is disconnecting from the network.
 297  *                      After it disconnects, it returns to DOWN state.
 298  *
 299  *      In:     start() Called in DOWN state to request protocol startup.
 300  *                      Returns new state: either UP or START (in this
 301  *                      case, the protocol will notify the core when it
 302  *                      finally comes UP).
 303  *              stop()  Called in START, UP or STOP state to request
 304  *                      protocol shutdown. Returns new state: either
 305  *                      DOWN or STOP (in this case, the protocol will
 306  *                      notify the core when it finally comes DOWN).
 307  *
 308  *      Out:    proto_notify_state() -- called by protocol instance when
 309  *                      it does any state transition not covered by
 310  *                      return values of start() and stop(). This includes
 311  *                      START->UP (delayed protocol startup), UP->STOP
 312  *                      (spontaneous shutdown) and STOP->DOWN (delayed
 313  *                      shutdown).
 314  */
 315
 316 #define PS_DOWN 0
 317 #define PS_START 1
 318 #define PS_UP 2
 319 #define PS_STOP 3
 320
 321 void proto_notify_state(struct proto *p, unsigned state);
 322
 323 /*
 324  *  [F] The feeder machine: (implemented in core routines)
 325  *
 326  *              HUNGRY    ---->   FEEDING
 327  *               ^                   |
 328  *               |                   V
 329  *              FLUSHING  <----   HAPPY
 330  *
 331  *      States: HUNGRY  Protocol either administratively down (i.e.,
 332  *                      disabled by the user) or temporarily down
 333  *                      (i.e., [P] is not UP)
 334  *              FEEDING The protocol came up and we're feeding it
 335  *                      initial routes. [P] is UP.
 336  *              HAPPY   The protocol is up and it's receiving normal
 337  *                      routing updates. [P] is UP.
 338  *              FLUSHING The protocol is down and we're removing its
 339  *                      routes from the table. [P] is STOP or DOWN.
 340  *
 341  *      Normal lifecycle of a protocol looks like:
 342  *
 343  *              HUNGRY/DOWN --> HUNGRY/START --> HUNGRY/UP -->
 344  *              FEEDING/UP --> HAPPY/UP --> FLUSHING/STOP|DOWN -->
 345  *              HUNGRY/STOP|DOWN --> HUNGRY/DOWN
 346  *
 347  *      Sometimes, protocol might switch from HAPPY/UP to FEEDING/UP
 348  *      if it wants to refeed the routes (for example BGP does so
 349  *      as a result of received ROUTE-REFRESH request).
 350  */
 351
 352
 353
 354 /*
 355  *      Debugging flags
 356  */
 357
 358 #define D_STATES 1              /* [core] State transitions */
 359 #define D_ROUTES 2              /* [core] Routes passed by the filters */
 360 #define D_FILTERS 4             /* [core] Routes rejected by the filters */
 361 #define D_IFACES 8              /* [core] Interface events */
 362 #define D_EVENTS 16             /* Protocol events */
 363 #define D_PACKETS 32            /* Packets sent/received */
 364
 365 #ifndef PARSER
 366 #define TRACE(flags, msg, args...) \
 367   do { if (p->p.debug & flags) log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 368 #endif
 369
 370
 371 /*
 372  *      MRTDump flags
 373  */
 374
 375 #define MD_STATES       1               /* Protocol state changes (BGP4MP_MESSAGE_AS4) */
 376 #define MD_MESSAGES     2               /* Protocol packets (BGP4MP_MESSAGE_AS4) */
 377
 378 /*
 379  *      Known unique protocol instances as referenced by config routines
 380  */
 381
 382 extern struct proto_config *cf_dev_proto;
 383
 384
 385 /*
 386  * Protocol limits
 387  */
 388
 389 #define PLD_RX          0       /* Receive limit */
 390 #define PLD_IN          1       /* Import limit */
 391 #define PLD_OUT         2       /* Export limit */
 392 #define PLD_MAX         3
 393
 394 #define PLA_NONE        0       /* No limit */
 395 #define PLA_WARN        1       /* Issue log warning */
 396 #define PLA_BLOCK       2       /* Block new routes */
 397 #define PLA_RESTART     4       /* Force protocol restart */
 398 #define PLA_DISABLE     5       /* Shutdown and disable protocol */
 399
 400 #define PLS_INITIAL     0       /* Initial limit state after protocol start */
 401 #define PLS_ACTIVE      1       /* Limit was hit */
 402 #define PLS_BLOCKED     2       /* Limit is active and blocking new routes */
 403
 404 struct channel_limit {
 405   u32 limit;                    /* Maximum number of prefixes */
 406   u8 action;                    /* Action to take (PLA_*) */
 407   u8 state;                     /* State of limit (PLS_*) */
 408 };
 409
 410 void channel_notify_limit(struct channel *c, struct channel_limit *l, int dir, u32 rt_count);
 411
 412
 413 /*
 414  *      Channels
 415  */
 416
 417 struct channel_class {
 418   uint channel_size;                    /* Size of channel data structure */
 419   uint config_size;                     /* Size of channel config data structure */
 420
 421   struct channel * (*init)(struct channel *, struct channel_config *);  /* Create new instance */
 422   int (*reconfigure)(struct channel *, struct channel_config *);        /* Try to reconfigure instance, returns success */
 423   int (*start)(struct channel *);       /* Start the instance */
 424   int (*shutdown)(struct channel *);    /* Stop the instance */
 425
 426   void (*copy_config)(struct channel_config *, struct channel_config *); /* Copy config from given channel instance */
 427 #if 0
 428   void (*preconfig)(struct protocol *, struct config *);        /* Just before configuring */
 429   void (*postconfig)(struct proto_config *);                    /* After configuring each instance */
 430
 431
 432   void (*dump)(struct proto *);                 /* Debugging dump */
 433   void (*dump_attrs)(struct rte *);             /* Dump protocol-dependent attributes */
 434   void (*cleanup)(struct proto *);              /* Called after shutdown when protocol became hungry/down */
 435   void (*get_status)(struct proto *, byte *buf); /* Get instance status (for `show protocols' command) */
 436   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
 437   int (*get_attr)(struct eattr *, byte *buf, int buflen);       /* ASCIIfy dynamic attribute (returns GA_*) */
 438   void (*show_proto_info)(struct proto *);      /* Show protocol info (for `show protocols all' command) */
 439
 440 #endif
 441 };
 442
 443 struct channel_config {
 444   node n;
 445   const char *name;
 446   const struct channel_class *channel;
 447
 448   struct rtable_config *table;          /* Table we're attached to */
 449   struct filter *in_filter, *out_filter; /* Attached filters */
 450   struct channel_limit rx_limit;        /* Limit for receiving routes from protocol
 451                                            (relevant when in_keep_filtered is active) */
 452   struct channel_limit in_limit;        /* Limit for importing routes from protocol */
 453   struct channel_limit out_limit;       /* Limit for exporting routes to protocol */
 454
 455   u8 net_type;                          /* Routing table network type (NET_*), 0 for undefined */
 456   u8 ra_mode;                           /* Mode of received route advertisements (RA_*) */
 457   u16 preference;                       /* Default route preference */
 458   u8 merge_limit;                       /* Maximal number of nexthops for RA_MERGED */
 459   u8 in_keep_filtered;                  /* Routes rejected in import filter are kept */
 460 };
 461
 462 struct channel {
 463   node n;                               /* Node in proto->channels */
 464   node table_node;                      /* Node in table->channels */
 465
 466   const char *name;                     /* Channel name (may be NULL) */
 467   const struct channel_class *channel;
 468   struct proto *proto;
 469
 470   struct rtable *table;
 471   struct filter *in_filter;             /* Input filter */
 472   struct filter *out_filter;            /* Output filter */
 473   struct channel_limit rx_limit;        /* Receive limit (for in_keep_filtered) */
 474   struct channel_limit in_limit;        /* Input limit */
 475   struct channel_limit out_limit;       /* Output limit */
 476
 477   struct event *feed_event;             /* Event responsible for feeding */
 478   struct fib_iterator feed_fit;         /* Routing table iterator used during feeding */
 479   struct proto_stats stats;             /* Per-channel protocol statistics */
 480
 481   u8 net_type;                          /* Routing table network type (NET_*), 0 for undefined */
 482   u8 ra_mode;                           /* Mode of received route advertisements (RA_*) */
 483   u16 preference;                       /* Default route preference */
 484   u8 merge_limit;                       /* Maximal number of nexthops for RA_MERGED */
 485   u8 in_keep_filtered;                  /* Routes rejected in import filter are kept */
 486   u8 disabled;
 487
 488   u8 channel_state;
 489   u8 export_state;                      /* Route export state (ES_*, see below) */
 490   u8 feed_active;
 491   u8 flush_active;
 492   u8 refeeding;                         /* We are refeeding (valid only if export_state == ES_FEEDING) */
 493   u8 reloadable;                        /* Hook reload_routes() is allowed on the channel */
 494   u8 gr_lock;                           /* Graceful restart mechanism should wait for this channel */
 495   u8 gr_wait;                           /* Route export to channel is postponed until graceful restart */
 496
 497   bird_clock_t last_state_change;       /* Time of last state transition */
 498 };
 499
 500
 501 /*
 502  * Channel states
 503  *
 504  * CS_DOWN - The initial and the final state of a channel. There is no route
 505  * exchange between the protocol and the table. Channel is not counted as
 506  * active. Channel keeps a ptr to the table, but do not lock the table and is
 507  * not linked in the table. Generally, new closed channels are created in
 508  * protocols' init() hooks. The protocol is expected to explicitly activate its
 509  * channels (by calling channel_init() or channel_open()).
 510  *
 511  * CS_START - The channel as a connection between the protocol and the table is
 512  * initialized (counted as active by the protocol, linked in the table and keeps
 513  * the table locked), but there is no current route exchange. There still may be
 514  * routes associated with the channel in the routing table if the channel falls
 515  * to CS_START from CS_UP. Generally, channels are initialized in protocols'
 516  * start() hooks when going to PS_START.
 517  *
 518  * CS_UP - The channel is initialized and the route exchange is allowed. Note
 519  * that even in CS_UP state, route export may still be down (ES_DOWN) by the
 520  * core decision (e.g. waiting for table convergence after graceful restart).
 521  * I.e., the protocol decides to open the channel but the core decides to start
 522  * route export. Route import (caused by rte_update() from the protocol) is not
 523  * restricted by that and is on volition of the protocol. Generally, channels
 524  * are opened in protocols' start() hooks when going to PS_UP.
 525  *
 526  * CS_FLUSHING - The transitional state between initialized channel and closed
 527  * channel. The channel is still initialized, but no route exchange is allowed.
 528  * Instead, the associated table is running flush loop to remove routes imported
 529  * through the channel. After that, the channel changes state to CS_DOWN and
 530  * is detached from the table (the table is unlocked and the channel is unlinked
 531  * from it). Unlike other states, the CS_FLUSHING state is not explicitly
 532  * entered or left by the protocol. A protocol may request to close a channel
 533  * (by calling channel_close()), which causes the channel to change state to
 534  * CS_FLUSHING and later to CS_DOWN. Also note that channels are closed
 535  * automatically by the core when the protocol is going down.
 536  *
 537  * Allowed transitions:
 538  *
 539  * CS_DOWN      -> CS_START / CS_UP
 540  * CS_START     -> CS_UP / CS_FLUSHING
 541  * CS_UP        -> CS_START / CS_FLUSHING
 542  * CS_FLUSHING  -> CS_DOWN (automatic)
 543  */
 544
 545 #define CS_DOWN         0
 546 #define CS_START        1
 547 #define CS_UP           2
 548 #define CS_FLUSHING     3
 549
 550 #define ES_DOWN         0
 551 #define ES_FEEDING      1
 552 #define ES_READY        2
 553
 554
 555 struct channel_config *proto_cf_find_channel(struct proto_config *p, uint net_type);
 556 static inline struct channel_config *proto_cf_main_channel(struct proto_config *pc)
 557 { struct channel_config *cc = HEAD(pc->channels); return NODE_VALID(cc) ? cc : NULL; }
 558
 559 struct channel *proto_find_channel_by_table(struct proto *p, struct rtable *t);
 560 struct channel *proto_add_channel(struct proto *p, struct channel_config *cf);
 561 int proto_configure_channel(struct proto *p, struct channel **c, struct channel_config *cf);
 562
 563 void channel_set_state(struct channel *c, uint state);
 564
 565 /*
 566 static inline void channel_init(struct channel *c) { channel_set_state(c, CS_START); }
 567 static inline void channel_open(struct channel *c) { channel_set_state(c, CS_UP); }
 568 static inline void channel_close(struct channel *c) { channel_set_state(c, CS_FLUSHING); }
 569 */
 570
 571 void channel_request_feeding(struct channel *c);
 572 void *channel_config_new(const struct channel_class *cc, uint net_type, struct proto_config *proto);
 573 int channel_reconfigure(struct channel *c, struct channel_config *cf);
 574
 575
 576 #endif