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bird 1.6.3

    1: /*
    2:  *	BIRD -- OSPF
    3:  *
    4:  *	(c) 1999--2004 Ondrej Filip <feela@network.cz>
    5:  *	(c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>
    6:  *	(c) 2009--2014 CZ.NIC z.s.p.o.
    7:  *
    8:  *	Can be freely distributed and used under the terms of the GNU GPL.
    9:  */
   10: 
   11: #ifndef _BIRD_OSPF_TOPOLOGY_H_
   12: #define _BIRD_OSPF_TOPOLOGY_H_
   13: 
   14: struct top_hash_entry
   15: {				/* Index for fast mapping (type,rtrid,LSid)->vertex */
   16:   snode n;
   17:   node cn;			/* For adding into list of candidates
   18: 				   in intra-area routing table calculation */
   19:   struct top_hash_entry *next;	/* Next in hash chain */
   20:   struct ospf_lsa_header lsa;
   21:   u16 lsa_type;			/* lsa.type processed and converted to common values (LSA_T_*) */
   22:   u16 init_age;			/* Initial value for lsa.age during inst_time */
   23:   u32 domain;			/* Area ID for area-wide LSAs, Iface ID for link-wide LSAs */
   24:   //  struct ospf_area *oa;
   25:   void *lsa_body;		/* May be NULL if LSA was flushed but hash entry was kept */
   26:   void *next_lsa_body;		/* For postponed LSA origination */
   27:   u16 next_lsa_blen;		/* For postponed LSA origination */
   28:   u16 next_lsa_opts;		/* For postponed LSA origination */
   29:   bird_clock_t inst_time;	/* Time of installation into DB */
   30:   struct ort *nf;		/* Reference fibnode for sum and ext LSAs, NULL for otherwise */
   31:   struct mpnh *nhs;		/* Computed nexthops - valid only in ospf_rt_spf() */
   32:   ip_addr lb;			/* In OSPFv2, link back address. In OSPFv3, any global address in the area useful for vlinks */
   33:   u32 lb_id;			/* Interface ID of link back iface (for bcast or NBMA networks) */
   34:   u32 dist;			/* Distance from the root */
   35:   int ret_count;		/* Number of retransmission lists referencing the entry */
   36:   u8 color;
   37: #define OUTSPF 0
   38: #define CANDIDATE 1
   39: #define INSPF 2
   40:   u8 mode;			/* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/
   41:   u8 nhs_reuse;			/* Whether nhs nodes can be reused during merging.
   42: 				   See a note in rt.c:add_cand() */
   43: };
   44: 
   45: 
   46: /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */
   47: #define LSA_BODY_DUMMY ((void *) 1)
   48: 
   49: /*
   50:  * LSA entry life cycle
   51:  *
   52:  * LSA entries are created by ospf_originate_lsa() (for locally originated LSAs)
   53:  * or ospf_install_lsa() (for LSAs received from neighbors). A regular (like
   54:  * newly originated) LSA entry has defined lsa_body nad lsa.age < %LSA_MAXAGE.
   55:  * When the LSA is requested to be flushed by ospf_flush_lsa(), the lsa.age is
   56:  * set to %LSA_MAXAGE and flooded. Flush process is finished asynchronously,
   57:  * when (at least) flooding is acknowledged by neighbors. This is detected in
   58:  * ospf_update_lsadb(), then ospf_clear_lsa() is called to free the LSA body but
   59:  * the LSA entry is kept. Such LSA does not formally exist, we keep an empty
   60:  * entry (until regular timeout) to know inst_time and lsa.sn in the case of
   61:  * later reorigination. After the timeout, LSA is removed by ospf_remove_lsa().
   62:  *
   63:  * When LSA origination is requested (by ospf_originate_lsa()). but it is not
   64:  * possible to do that immediately (because of MinLSInterval or because the
   65:  * sequence number is wrapping), The new LSA is scheduled for later origination
   66:  * in next_lsa_* fields of the LSA entry. The later origination is handled by
   67:  * ospf_originate_next_lsa() called from ospf_update_lsadb(). We can see that
   68:  * both real origination and final flush is asynchronous to ospf_originate_lsa()
   69:  * and ospf_flush_lsa().
   70:  *
   71:  * LSA entry therefore could be in three basic states:
   72:  * R - regular (lsa.age < %LSA_MAXAGE, lsa_body != NULL)
   73:  * F - flushing (lsa.age == %LSA_MAXAGE, lsa_body != NULL)
   74:  * E - empty (lsa.age == %LSA_MAXAGE, lsa_body == NULL)
   75:  *
   76:  * And these states are doubled based on whether the next LSA is scheduled
   77:  * (next_lsa_body != NULL, -n suffix) or not (next_lsa_body == NULL). We also
   78:  * use X for a state of non-existentce. We have this basic state graph
   79:  * (transitions from any state to R are omitted for clarity):
   80:  *
   81:  *  X --> R ---> F ---> E --> X
   82:  *        | \  / |      |
   83:  *        |  \/  |      |
   84:  *        |  /\  |      |
   85:  *        | /  \ |      |
   86:  *        Rn --> Fn --> En
   87:  *
   88:  * The transitions are:
   89:  *
   90:  * any state -> R		- new LSA origination requested and executed
   91:  * R -> Rn, F -> Fn, E -> En	- new LSA origination requested and postponed
   92:  * R -> Fn			- new LSA origination requested, seqnum wrapping
   93:  * Rn,Fn,En -> R		- postponed LSA finally originated
   94:  * R -> R			- LSA refresh done
   95:  * R -> Fn			- LSA refresh with seqnum wrapping
   96:  * R -> F, Rn -> Fn		- LSA age timeout
   97:  * R,Rn,Fn -> F, En -> E	- LSA flush requested
   98:  * F -> E, Fn -> En		- LSA flush done (acknowledged)
   99:  * E -> X			- LSA real age timeout (or immediate for received LSA)
  100:  *
  101:  * The 'origination requested' and 'flush requested' transitions are triggered
  102:  * and done by ospf_originate_lsa() and ospf_flush_lsa(), the rest is handled
  103:  * asynchronously by ospf_update_lsadb().
  104:  *
  105:  * The situation is significantly simpler for non-local (received) LSAs - there
  106:  * is no postponed origination and after flushing is done, LSAs are immediately
  107:  * removed, so it is just X -> R -> F -> X, or X -> F -> X (when MaxAge LSA is
  108:  * received).
  109:  *
  110:  * There are also some special cases related to handling of received unknown
  111:  * self-originated LSAs in ospf_advance_lsa():
  112:  * X -> F		- LSA is received and immediately flushed
  113:  * R,Rn -> Fn		- LSA with MaxSeqNo received and flushed, current LSA scheduled
  114:  */
  115: 
  116: 
  117: #define LSA_M_BASIC	0
  118: #define LSA_M_EXPORT	1
  119: #define LSA_M_RTCALC	2
  120: #define LSA_M_STALE	3
  121: 
  122: /*
  123:  * LSA entry modes:
  124:  *
  125:  * LSA_M_BASIC - The LSA is explicitly originated using ospf_originate_lsa() and
  126:  * explicitly flushed using ospf_flush_lsa(). When the LSA is changed, the
  127:  * routing table calculation is scheduled. This is also the mode used for LSAs
  128:  * received from neighbors. Example: Router-LSAs, Network-LSAs.
  129:  *
  130:  * LSA_M_EXPORT - like LSA_M_BASIC, but the routing table calculation does not
  131:  * depend on the LSA. Therefore, the calculation is not scheduled when the LSA
  132:  * is changed. Example: AS-external-LSAs for exported routes.
  133:  *
  134:  * LSA_M_RTCALC - The LSA has to be requested using ospf_originate_lsa() during
  135:  * each routing table calculation, otherwise it is flushed automatically at the
  136:  * end of the calculation. The LSA is a result of the calculation and not a
  137:  * source for it. Therefore, the calculation is not scheduled when the LSA is
  138:  * changed. Example: Summary-LSAs.
  139:  *
  140:  * LSA_M_STALE - Temporary state for LSA_M_RTCALC that is not requested during
  141:  * the current routing table calculation.
  142:  *
  143:  *
  144:  * Note that we do not schedule the routing table calculation when the age of
  145:  * LSA_M_BASIC LSA is changed to MaxAge because of the sequence number wrapping,
  146:  * As it will be switched back to a regular one ASAP.
  147:  */
  148: 
  149: 
  150: struct top_graph
  151: {
  152:   pool *pool;			/* Pool we allocate from */
  153:   slab *hash_slab;		/* Slab for hash entries */
  154:   struct top_hash_entry **hash_table;	/* Hashing (modelled a`la fib) */
  155:   uint ospf2;			/* Whether it is for OSPFv2 or OSPFv3 */
  156:   uint hash_size;
  157:   uint hash_order;
  158:   uint hash_mask;
  159:   uint hash_entries;
  160:   uint hash_entries_min, hash_entries_max;
  161: };
  162: 
  163: struct ospf_new_lsa
  164: {
  165:   u16 type;
  166:   u8  mode;
  167:   u32 dom;
  168:   u32 id;
  169:   u16 opts;
  170:   u16 length;
  171:   struct ospf_iface *ifa;
  172:   struct ort *nf;
  173: };
  174: 
  175: struct top_graph *ospf_top_new(struct ospf_proto *p, pool *pool);
  176: void ospf_top_free(struct top_graph *f);
  177: 
  178: struct top_hash_entry * ospf_install_lsa(struct ospf_proto *p, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
  179: struct top_hash_entry * ospf_originate_lsa(struct ospf_proto *p, struct ospf_new_lsa *lsa);
  180: void ospf_advance_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
  181: void ospf_flush_lsa(struct ospf_proto *p, struct top_hash_entry *en);
  182: void ospf_update_lsadb(struct ospf_proto *p);
  183: 
  184: static inline void ospf_flush2_lsa(struct ospf_proto *p, struct top_hash_entry **en)
  185: { if (*en) { ospf_flush_lsa(p, *en); *en = NULL; } }
  186: 
  187: void ospf_originate_sum_net_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric);
  188: void ospf_originate_sum_rt_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric, u32 options);
  189: void ospf_originate_ext_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, u8 mode, u32 metric, u32 ebit, ip_addr fwaddr, u32 tag, int pbit);
  190: 
  191: void ospf_rt_notify(struct proto *P, rtable *tbl, net *n, rte *new, rte *old, ea_list *attrs);
  192: void ospf_update_topology(struct ospf_proto *p);
  193: 
  194: struct top_hash_entry *ospf_hash_find(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
  195: struct top_hash_entry *ospf_hash_get(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
  196: void ospf_hash_delete(struct top_graph *, struct top_hash_entry *);
  197: 
  198: static inline struct top_hash_entry * ospf_hash_find_entry(struct top_graph *f, struct top_hash_entry *en)
  199: { return ospf_hash_find(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
  200: 
  201: static inline struct top_hash_entry * ospf_hash_get_entry(struct top_graph *f, struct top_hash_entry *en)
  202: { return ospf_hash_get(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
  203: 
  204: struct top_hash_entry * ospf_hash_find_rt(struct top_graph *f, u32 domain, u32 rtr);
  205: struct top_hash_entry * ospf_hash_find_rt3_first(struct top_graph *f, u32 domain, u32 rtr);
  206: struct top_hash_entry * ospf_hash_find_rt3_next(struct top_hash_entry *e);
  207: 
  208: struct top_hash_entry * ospf_hash_find_net2(struct top_graph *f, u32 domain, u32 id);
  209: 
  210: /* In OSPFv2, id is network IP prefix (lsa.id) while lsa.rt field is unknown
  211:    In OSPFv3, id is lsa.rt of DR while nif is neighbor iface id (lsa.id) */
  212: static inline struct top_hash_entry *
  213: ospf_hash_find_net(struct top_graph *f, u32 domain, u32 id, u32 nif)
  214: {
  215:   return f->ospf2 ?
  216:     ospf_hash_find_net2(f, domain, id) :
  217:     ospf_hash_find(f, domain, nif, id, LSA_T_NET);
  218: }
  219: 
  220: 
  221: #endif /* _BIRD_OSPF_TOPOLOGY_H_ */