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 "nest/route.h"
  16 #include "conf/conf.h"
  17
  18 struct iface;
  19 struct ifa;
  20 struct rtable;
  21 struct rte;
  22 struct neighbor;
  23 struct rta;
  24 struct network;
  25 struct proto_config;
  26 struct channel_limit;
  27 struct channel_config;
  28 struct config;
  29 struct proto;
  30 struct channel;
  31 struct ea_list;
  32 struct eattr;
  33 struct symbol;
  34
  35
  36 /*
  37  *      Routing Protocol
  38  */
  39
  40 struct protocol {
  41   node n;
  42   char *name;
  43   char *template;                       /* Template for automatic generation of names */
  44   int name_counter;                     /* Counter for automatic name generation */
  45   int attr_class;                       /* Attribute class known to this protocol */
  46   uint preference;                      /* Default protocol preference */
  47   uint channel_mask;                    /* Mask of accepted channel types (NB_*) */
  48   uint proto_size;                      /* Size of protocol data structure */
  49   uint config_size;                     /* Size of protocol config data structure */
  50
  51   void (*preconfig)(struct protocol *, struct config *);        /* Just before configuring */
  52   void (*postconfig)(struct proto_config *);                    /* After configuring each instance */
  53   struct proto * (*init)(struct proto_config *);                /* Create new instance */
  54   int (*reconfigure)(struct proto *, struct proto_config *);    /* Try to reconfigure instance, returns success */
  55   void (*dump)(struct proto *);                 /* Debugging dump */
  56   void (*dump_attrs)(struct rte *);             /* Dump protocol-dependent attributes */
  57   int (*start)(struct proto *);                 /* Start the instance */
  58   int (*shutdown)(struct proto *);              /* Stop the instance */
  59   void (*cleanup)(struct proto *);              /* Called after shutdown when protocol became hungry/down */
  60   void (*get_status)(struct proto *, byte *buf); /* Get instance status (for `show protocols' command) */
  61   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
  62   int (*get_attr)(struct eattr *, byte *buf, int buflen);       /* ASCIIfy dynamic attribute (returns GA_*) */
  63   void (*show_proto_info)(struct proto *);      /* Show protocol info (for `show protocols all' command) */
  64   void (*copy_config)(struct proto_config *, struct proto_config *);    /* Copy config from given protocol instance */
  65 };
  66
  67 void protos_build(void);
  68 void proto_build(struct protocol *);
  69 void protos_preconfig(struct config *);
  70 void protos_commit(struct config *new, struct config *old, int force_restart, int type);
  71 void protos_dump_all(void);
  72
  73 #define GA_UNKNOWN      0               /* Attribute not recognized */
  74 #define GA_NAME         1               /* Result = name */
  75 #define GA_FULL         2               /* Result = both name and value */
  76
  77 /*
  78  *      Known protocols
  79  */
  80
  81 extern struct protocol
  82   proto_device, proto_radv, proto_rip, proto_static,
  83   proto_ospf, proto_pipe, proto_bgp, proto_bfd, proto_babel, proto_rpki;
  84
  85 /*
  86  *      Routing Protocol Instance
  87  */
  88
  89 struct proto_config {
  90   node n;
  91   struct config *global;                /* Global configuration data */
  92   struct protocol *protocol;            /* Protocol */
  93   struct proto *proto;                  /* Instance we've created */
  94   char *name;
  95   char *dsc;
  96   int class;                            /* SYM_PROTO or SYM_TEMPLATE */
  97   u8 net_type;                          /* Protocol network type (NET_*), 0 for undefined */
  98   u8 disabled;                          /* Protocol enabled/disabled by default */
  99   u32 debug, mrtdump;                   /* Debugging bitfields, both use D_* constants */
 100   u32 router_id;                        /* Protocol specific router ID */
 101
 102   list channels;                        /* List of channel configs (struct channel_config) */
 103   struct iface *vrf;                    /* Related VRF instance, NULL if global */
 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   struct iface *vrf;                    /* Related VRF instance, NULL if global */
 147
 148   char *name;                           /* Name of this instance (== cf->name) */
 149   u32 debug;                            /* Debugging flags */
 150   u32 mrtdump;                          /* MRTDump flags */
 151   uint active_channels;                 /* Number of active channels */
 152   byte net_type;                        /* Protocol network type (NET_*), 0 for undefined */
 153   byte disabled;                        /* Manually disabled */
 154   byte proto_state;                     /* Protocol state machine (PS_*, see below) */
 155   byte active;                          /* From PS_START to cleanup after PS_STOP */
 156   byte do_start;                        /* Start actions are scheduled */
 157   byte do_stop;                         /* Stop actions are scheduled */
 158   byte reconfiguring;                   /* We're shutting down due to reconfiguration */
 159   byte gr_recovery;                     /* Protocol should participate in graceful restart recovery */
 160   byte down_sched;                      /* Shutdown is scheduled for later (PDS_*) */
 161   byte down_code;                       /* Reason for shutdown (PDC_* codes) */
 162   u32 hash_key;                         /* Random key used for hashing of neighbors */
 163   btime last_state_change;              /* Time of last state transition */
 164   char *last_state_name_announced;      /* Last state name we've announced to the user */
 165   char *message;                        /* State-change message, allocated from proto_pool */
 166
 167   /*
 168    *    General protocol hooks:
 169    *
 170    *       if_notify    Notify protocol about interface state changes.
 171    *       ifa_notify   Notify protocol about interface address changes.
 172    *       rt_notify    Notify protocol about routing table updates.
 173    *       neigh_notify Notify protocol about neighbor cache events.
 174    *       make_tmp_attrs  Construct ea_list from private attrs stored in rte.
 175    *       store_tmp_attrs Store private attrs back to the rte.
 176    *       import_control  Called as the first step of the route importing process.
 177    *                    It can construct a new rte, add private attributes and
 178    *                    decide whether the route shall be imported: 1=yes, -1=no,
 179    *                    0=process it through the import filter set by the user.
 180    *       reload_routes   Request channel to reload all its routes to the core
 181    *                    (using rte_update()). Returns: 0=reload cannot be done,
 182    *                    1= reload is scheduled and will happen (asynchronously).
 183    *       feed_begin   Notify channel about beginning of route feeding.
 184    *       feed_end     Notify channel about finish of route feeding.
 185    */
 186
 187   void (*if_notify)(struct proto *, unsigned flags, struct iface *i);
 188   void (*ifa_notify)(struct proto *, unsigned flags, struct ifa *a);
 189   void (*rt_notify)(struct proto *, struct channel *, struct network *net, struct rte *new, struct rte *old, struct ea_list *attrs);
 190   void (*neigh_notify)(struct neighbor *neigh);
 191   struct ea_list *(*make_tmp_attrs)(struct rte *rt, struct linpool *pool);
 192   void (*store_tmp_attrs)(struct rte *rt, struct ea_list *attrs);
 193   int (*import_control)(struct proto *, struct rte **rt, struct ea_list **attrs, struct linpool *pool);
 194   void (*reload_routes)(struct channel *);
 195   void (*feed_begin)(struct channel *, int initial);
 196   void (*feed_end)(struct channel *);
 197
 198   /*
 199    *    Routing entry hooks (called only for routes belonging to this protocol):
 200    *
 201    *       rte_recalculate Called at the beginning of the best route selection
 202    *       rte_better   Compare two rte's and decide which one is better (1=first, 0=second).
 203    *       rte_same     Compare two rte's and decide whether they are identical (1=yes, 0=no).
 204    *       rte_mergable Compare two rte's and decide whether they could be merged (1=yes, 0=no).
 205    *       rte_insert   Called whenever a rte is inserted to a routing table.
 206    *       rte_remove   Called whenever a rte is removed from the routing table.
 207    */
 208
 209   int (*rte_recalculate)(struct rtable *, struct network *, struct rte *, struct rte *, struct rte *);
 210   int (*rte_better)(struct rte *, struct rte *);
 211   int (*rte_same)(struct rte *, struct rte *);
 212   int (*rte_mergable)(struct rte *, struct rte *);
 213   void (*rte_insert)(struct network *, struct rte *);
 214   void (*rte_remove)(struct network *, struct rte *);
 215
 216   /* Hic sunt protocol-specific data */
 217 };
 218
 219 struct proto_spec {
 220   void *ptr;
 221   int patt;
 222 };
 223
 224
 225 #define PDS_DISABLE             1       /* Proto disable scheduled */
 226 #define PDS_RESTART             2       /* Proto restart scheduled */
 227
 228 #define PDC_CF_REMOVE           0x01    /* Removed in new config */
 229 #define PDC_CF_DISABLE          0x02    /* Disabled in new config */
 230 #define PDC_CF_RESTART          0x03    /* Restart due to reconfiguration */
 231 #define PDC_CMD_DISABLE         0x11    /* Result of disable command */
 232 #define PDC_CMD_RESTART         0x12    /* Result of restart command */
 233 #define PDC_CMD_SHUTDOWN        0x13    /* Result of global shutdown */
 234 #define PDC_RX_LIMIT_HIT        0x21    /* Route receive limit reached */
 235 #define PDC_IN_LIMIT_HIT        0x22    /* Route import limit reached */
 236 #define PDC_OUT_LIMIT_HIT       0x23    /* Route export limit reached */
 237
 238
 239 void *proto_new(struct proto_config *);
 240 void *proto_config_new(struct protocol *, int class);
 241 void proto_copy_config(struct proto_config *dest, struct proto_config *src);
 242 void proto_set_message(struct proto *p, char *msg, int len);
 243
 244 void graceful_restart_recovery(void);
 245 void graceful_restart_init(void);
 246 void graceful_restart_show_status(void);
 247 void channel_graceful_restart_lock(struct channel *c);
 248 void channel_graceful_restart_unlock(struct channel *c);
 249
 250 #define DEFAULT_GR_WAIT 240
 251
 252 void channel_show_limit(struct channel_limit *l, const char *dsc);
 253 void channel_show_info(struct channel *c);
 254
 255 void proto_cmd_show(struct proto *, uintptr_t, int);
 256 void proto_cmd_disable(struct proto *, uintptr_t, int);
 257 void proto_cmd_enable(struct proto *, uintptr_t, int);
 258 void proto_cmd_restart(struct proto *, uintptr_t, int);
 259 void proto_cmd_reload(struct proto *, uintptr_t, int);
 260 void proto_cmd_debug(struct proto *, uintptr_t, int);
 261 void proto_cmd_mrtdump(struct proto *, uintptr_t, int);
 262
 263 void proto_apply_cmd(struct proto_spec ps, void (* cmd)(struct proto *, uintptr_t, int), int restricted, uintptr_t arg);
 264 struct proto *proto_get_named(struct symbol *, struct protocol *);
 265
 266 #define CMD_RELOAD      0
 267 #define CMD_RELOAD_IN   1
 268 #define CMD_RELOAD_OUT  2
 269
 270 static inline u32
 271 proto_get_router_id(struct proto_config *pc)
 272 {
 273   return pc->router_id ? pc->router_id : pc->global->router_id;
 274 }
 275
 276 static inline struct ea_list *
 277 rte_make_tmp_attrs(struct rte *rt, struct linpool *pool)
 278 {
 279   struct ea_list *(*mta)(struct rte *rt, struct linpool *pool);
 280   mta = rt->attrs->src->proto->make_tmp_attrs;
 281   return mta ? mta(rt, pool) : NULL;
 282 }
 283
 284 /* Moved from route.h to avoid dependency conflicts */
 285 static inline void rte_update(struct proto *p, const net_addr *n, rte *new) { rte_update2(p->main_channel, n, new, p->main_source); }
 286
 287 extern pool *proto_pool;
 288 extern list proto_list;
 289
 290 /*
 291  *  Each protocol instance runs two different state machines:
 292  *
 293  *  [P] The protocol machine: (implemented inside protocol)
 294  *
 295  *              DOWN    ---->    START
 296  *                ^                |
 297  *                |                V
 298  *              STOP    <----     UP
 299  *
 300  *      States: DOWN    Protocol is down and it's waiting for the core
 301  *                      requesting protocol start.
 302  *              START   Protocol is waiting for connection with the rest
 303  *                      of the network and it's not willing to accept
 304  *                      packets. When it connects, it goes to UP state.
 305  *              UP      Protocol is up and running. When the network
 306  *                      connection breaks down or the core requests
 307  *                      protocol to be terminated, it goes to STOP state.
 308  *              STOP    Protocol is disconnecting from the network.
 309  *                      After it disconnects, it returns to DOWN state.
 310  *
 311  *      In:     start() Called in DOWN state to request protocol startup.
 312  *                      Returns new state: either UP or START (in this
 313  *                      case, the protocol will notify the core when it
 314  *                      finally comes UP).
 315  *              stop()  Called in START, UP or STOP state to request
 316  *                      protocol shutdown. Returns new state: either
 317  *                      DOWN or STOP (in this case, the protocol will
 318  *                      notify the core when it finally comes DOWN).
 319  *
 320  *      Out:    proto_notify_state() -- called by protocol instance when
 321  *                      it does any state transition not covered by
 322  *                      return values of start() and stop(). This includes
 323  *                      START->UP (delayed protocol startup), UP->STOP
 324  *                      (spontaneous shutdown) and STOP->DOWN (delayed
 325  *                      shutdown).
 326  */
 327
 328 #define PS_DOWN 0
 329 #define PS_START 1
 330 #define PS_UP 2
 331 #define PS_STOP 3
 332
 333 void proto_notify_state(struct proto *p, unsigned state);
 334
 335 /*
 336  *  [F] The feeder machine: (implemented in core routines)
 337  *
 338  *              HUNGRY    ---->   FEEDING
 339  *               ^                   |
 340  *               |                   V
 341  *              FLUSHING  <----   HAPPY
 342  *
 343  *      States: HUNGRY  Protocol either administratively down (i.e.,
 344  *                      disabled by the user) or temporarily down
 345  *                      (i.e., [P] is not UP)
 346  *              FEEDING The protocol came up and we're feeding it
 347  *                      initial routes. [P] is UP.
 348  *              HAPPY   The protocol is up and it's receiving normal
 349  *                      routing updates. [P] is UP.
 350  *              FLUSHING The protocol is down and we're removing its
 351  *                      routes from the table. [P] is STOP or DOWN.
 352  *
 353  *      Normal lifecycle of a protocol looks like:
 354  *
 355  *              HUNGRY/DOWN --> HUNGRY/START --> HUNGRY/UP -->
 356  *              FEEDING/UP --> HAPPY/UP --> FLUSHING/STOP|DOWN -->
 357  *              HUNGRY/STOP|DOWN --> HUNGRY/DOWN
 358  *
 359  *      Sometimes, protocol might switch from HAPPY/UP to FEEDING/UP
 360  *      if it wants to refeed the routes (for example BGP does so
 361  *      as a result of received ROUTE-REFRESH request).
 362  */
 363
 364
 365
 366 /*
 367  *      Debugging flags
 368  */
 369
 370 #define D_STATES 1              /* [core] State transitions */
 371 #define D_ROUTES 2              /* [core] Routes passed by the filters */
 372 #define D_FILTERS 4             /* [core] Routes rejected by the filters */
 373 #define D_IFACES 8              /* [core] Interface events */
 374 #define D_EVENTS 16             /* Protocol events */
 375 #define D_PACKETS 32            /* Packets sent/received */
 376
 377 #ifndef PARSER
 378 #define TRACE(flags, msg, args...) \
 379   do { if (p->p.debug & flags) log(L_TRACE "%s: " msg, p->p.name , ## args ); } while(0)
 380 #endif
 381
 382
 383 /*
 384  *      MRTDump flags
 385  */
 386
 387 #define MD_STATES       1               /* Protocol state changes (BGP4MP_MESSAGE_AS4) */
 388 #define MD_MESSAGES     2               /* Protocol packets (BGP4MP_MESSAGE_AS4) */
 389
 390 /*
 391  *      Known unique protocol instances as referenced by config routines
 392  */
 393
 394 extern struct proto_config *cf_dev_proto;
 395
 396
 397 /*
 398  * Protocol limits
 399  */
 400
 401 #define PLD_RX          0       /* Receive limit */
 402 #define PLD_IN          1       /* Import limit */
 403 #define PLD_OUT         2       /* Export limit */
 404 #define PLD_MAX         3
 405
 406 #define PLA_NONE        0       /* No limit */
 407 #define PLA_WARN        1       /* Issue log warning */
 408 #define PLA_BLOCK       2       /* Block new routes */
 409 #define PLA_RESTART     4       /* Force protocol restart */
 410 #define PLA_DISABLE     5       /* Shutdown and disable protocol */
 411
 412 #define PLS_INITIAL     0       /* Initial limit state after protocol start */
 413 #define PLS_ACTIVE      1       /* Limit was hit */
 414 #define PLS_BLOCKED     2       /* Limit is active and blocking new routes */
 415
 416 struct channel_limit {
 417   u32 limit;                    /* Maximum number of prefixes */
 418   u8 action;                    /* Action to take (PLA_*) */
 419   u8 state;                     /* State of limit (PLS_*) */
 420 };
 421
 422 void channel_notify_limit(struct channel *c, struct channel_limit *l, int dir, u32 rt_count);
 423
 424
 425 /*
 426  *      Channels
 427  */
 428
 429 struct channel_class {
 430   uint channel_size;                    /* Size of channel data structure */
 431   uint config_size;                     /* Size of channel config data structure */
 432
 433   void (*init)(struct channel *, struct channel_config *);      /* Create new instance */
 434   int (*reconfigure)(struct channel *, struct channel_config *);        /* Try to reconfigure instance, returns success */
 435   int (*start)(struct channel *);       /* Start the instance */
 436   void (*shutdown)(struct channel *);   /* Stop the instance */
 437   void (*cleanup)(struct channel *);    /* Channel finished flush */
 438
 439   void (*copy_config)(struct channel_config *, struct channel_config *); /* Copy config from given channel instance */
 440 #if 0
 441   XXXX;
 442   void (*preconfig)(struct protocol *, struct config *);        /* Just before configuring */
 443   void (*postconfig)(struct proto_config *);                    /* After configuring each instance */
 444
 445
 446   void (*dump)(struct proto *);                 /* Debugging dump */
 447   void (*dump_attrs)(struct rte *);             /* Dump protocol-dependent attributes */
 448
 449   void (*get_status)(struct proto *, byte *buf); /* Get instance status (for `show protocols' command) */
 450   void (*get_route_info)(struct rte *, byte *buf, struct ea_list *attrs); /* Get route information (for `show route' command) */
 451   int (*get_attr)(struct eattr *, byte *buf, int buflen);       /* ASCIIfy dynamic attribute (returns GA_*) */
 452   void (*show_proto_info)(struct proto *);      /* Show protocol info (for `show protocols all' command) */
 453
 454 #endif
 455 };
 456
 457 extern struct channel_class channel_bgp;
 458
 459 struct channel_config {
 460   node n;
 461   const char *name;
 462   const struct channel_class *channel;
 463
 464   struct rtable_config *table;          /* Table we're attached to */
 465   struct filter *in_filter, *out_filter; /* Attached filters */
 466   struct channel_limit rx_limit;        /* Limit for receiving routes from protocol
 467                                            (relevant when in_keep_filtered is active) */
 468   struct channel_limit in_limit;        /* Limit for importing routes from protocol */
 469   struct channel_limit out_limit;       /* Limit for exporting routes to protocol */
 470
 471   u8 net_type;                          /* Routing table network type (NET_*), 0 for undefined */
 472   u8 ra_mode;                           /* Mode of received route advertisements (RA_*) */
 473   u16 preference;                       /* Default route preference */
 474   u8 merge_limit;                       /* Maximal number of nexthops for RA_MERGED */
 475   u8 in_keep_filtered;                  /* Routes rejected in import filter are kept */
 476 };
 477
 478 struct channel {
 479   node n;                               /* Node in proto->channels */
 480   node table_node;                      /* Node in table->channels */
 481
 482   const char *name;                     /* Channel name (may be NULL) */
 483   const struct channel_class *channel;
 484   struct proto *proto;
 485
 486   struct rtable *table;
 487   struct filter *in_filter;             /* Input filter */
 488   struct filter *out_filter;            /* Output filter */
 489   struct channel_limit rx_limit;        /* Receive limit (for in_keep_filtered) */
 490   struct channel_limit in_limit;        /* Input limit */
 491   struct channel_limit out_limit;       /* Output limit */
 492
 493   struct event *feed_event;             /* Event responsible for feeding */
 494   struct fib_iterator feed_fit;         /* Routing table iterator used during feeding */
 495   struct proto_stats stats;             /* Per-channel protocol statistics */
 496
 497   u8 net_type;                          /* Routing table network type (NET_*), 0 for undefined */
 498   u8 ra_mode;                           /* Mode of received route advertisements (RA_*) */
 499   u16 preference;                       /* Default route preference */
 500   u8 merge_limit;                       /* Maximal number of nexthops for RA_MERGED */
 501   u8 in_keep_filtered;                  /* Routes rejected in import filter are kept */
 502   u8 disabled;
 503   u8 stale;                             /* Used in reconfiguration */
 504
 505   u8 channel_state;
 506   u8 export_state;                      /* Route export state (ES_*, see below) */
 507   u8 feed_active;
 508   u8 flush_active;
 509   u8 refeeding;                         /* We are refeeding (valid only if export_state == ES_FEEDING) */
 510   u8 reloadable;                        /* Hook reload_routes() is allowed on the channel */
 511   u8 gr_lock;                           /* Graceful restart mechanism should wait for this channel */
 512   u8 gr_wait;                           /* Route export to channel is postponed until graceful restart */
 513
 514   btime last_state_change;              /* Time of last state transition */
 515 };
 516
 517
 518 /*
 519  * Channel states
 520  *
 521  * CS_DOWN - The initial and the final state of a channel. There is no route
 522  * exchange between the protocol and the table. Channel is not counted as
 523  * active. Channel keeps a ptr to the table, but do not lock the table and is
 524  * not linked in the table. Generally, new closed channels are created in
 525  * protocols' init() hooks. The protocol is expected to explicitly activate its
 526  * channels (by calling channel_init() or channel_open()).
 527  *
 528  * CS_START - The channel as a connection between the protocol and the table is
 529  * initialized (counted as active by the protocol, linked in the table and keeps
 530  * the table locked), but there is no current route exchange. There still may be
 531  * routes associated with the channel in the routing table if the channel falls
 532  * to CS_START from CS_UP. Generally, channels are initialized in protocols'
 533  * start() hooks when going to PS_START.
 534  *
 535  * CS_UP - The channel is initialized and the route exchange is allowed. Note
 536  * that even in CS_UP state, route export may still be down (ES_DOWN) by the
 537  * core decision (e.g. waiting for table convergence after graceful restart).
 538  * I.e., the protocol decides to open the channel but the core decides to start
 539  * route export. Route import (caused by rte_update() from the protocol) is not
 540  * restricted by that and is on volition of the protocol. Generally, channels
 541  * are opened in protocols' start() hooks when going to PS_UP.
 542  *
 543  * CS_FLUSHING - The transitional state between initialized channel and closed
 544  * channel. The channel is still initialized, but no route exchange is allowed.
 545  * Instead, the associated table is running flush loop to remove routes imported
 546  * through the channel. After that, the channel changes state to CS_DOWN and
 547  * is detached from the table (the table is unlocked and the channel is unlinked
 548  * from it). Unlike other states, the CS_FLUSHING state is not explicitly
 549  * entered or left by the protocol. A protocol may request to close a channel
 550  * (by calling channel_close()), which causes the channel to change state to
 551  * CS_FLUSHING and later to CS_DOWN. Also note that channels are closed
 552  * automatically by the core when the protocol is going down.
 553  *
 554  * Allowed transitions:
 555  *
 556  * CS_DOWN      -> CS_START / CS_UP
 557  * CS_START     -> CS_UP / CS_FLUSHING
 558  * CS_UP        -> CS_START / CS_FLUSHING
 559  * CS_FLUSHING  -> CS_DOWN (automatic)
 560  */
 561
 562 #define CS_DOWN         0
 563 #define CS_START        1
 564 #define CS_UP           2
 565 #define CS_FLUSHING     3
 566
 567 #define ES_DOWN         0
 568 #define ES_FEEDING      1
 569 #define ES_READY        2
 570
 571
 572 struct channel_config *proto_cf_find_channel(struct proto_config *p, uint net_type);
 573 static inline struct channel_config *proto_cf_main_channel(struct proto_config *pc)
 574 { struct channel_config *cc = HEAD(pc->channels); return NODE_VALID(cc) ? cc : NULL; }
 575
 576 struct channel *proto_find_channel_by_table(struct proto *p, struct rtable *t);
 577 struct channel *proto_find_channel_by_name(struct proto *p, const char *n);
 578 struct channel *proto_add_channel(struct proto *p, struct channel_config *cf);
 579 int proto_configure_channel(struct proto *p, struct channel **c, struct channel_config *cf);
 580
 581 void channel_set_state(struct channel *c, uint state);
 582
 583 static inline void channel_init(struct channel *c) { channel_set_state(c, CS_START); }
 584 static inline void channel_open(struct channel *c) { channel_set_state(c, CS_UP); }
 585 static inline void channel_close(struct channel *c) { channel_set_state(c, CS_FLUSHING); }
 586
 587 void channel_request_feeding(struct channel *c);
 588 void *channel_config_new(const struct channel_class *cc, uint net_type, struct proto_config *proto);
 589 int channel_reconfigure(struct channel *c, struct channel_config *cf);
 590
 591
 592 #endif