/* * BIRD -- OSPF * * (c) 1999--2004 Ondrej Filip * (c) 2009--2014 Ondrej Zajicek * (c) 2009--2014 CZ.NIC z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ #ifndef _BIRD_OSPF_TOPOLOGY_H_ #define _BIRD_OSPF_TOPOLOGY_H_ struct top_hash_entry { /* Index for fast mapping (type,rtrid,LSid)->vertex */ snode n; node cn; /* For adding into list of candidates in intra-area routing table calculation */ struct top_hash_entry *next; /* Next in hash chain */ struct ospf_lsa_header lsa; u16 lsa_type; /* lsa.type processed and converted to common values (LSA_T_*) */ u16 init_age; /* Initial value for lsa.age during inst_time */ u32 domain; /* Area ID for area-wide LSAs, Iface ID for link-wide LSAs */ // struct ospf_area *oa; void *lsa_body; /* May be NULL if LSA was flushed but hash entry was kept */ void *next_lsa_body; /* For postponed LSA origination */ u16 next_lsa_blen; /* For postponed LSA origination */ u16 next_lsa_opts; /* For postponed LSA origination */ bird_clock_t inst_time; /* Time of installation into DB */ struct ort *nf; /* Reference fibnode for sum and ext LSAs, NULL for otherwise */ struct mpnh *nhs; /* Computed nexthops - valid only in ospf_rt_spf() */ ip_addr lb; /* In OSPFv2, link back address. In OSPFv3, any global address in the area useful for vlinks */ u32 lb_id; /* Interface ID of link back iface (for bcast or NBMA networks) */ u32 dist; /* Distance from the root */ int ret_count; /* Number of retransmission lists referencing the entry */ u8 color; #define OUTSPF 0 #define CANDIDATE 1 #define INSPF 2 u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/ u8 nhs_reuse; /* Whether nhs nodes can be reused during merging. See a note in rt.c:merge_nexthops() */ }; /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */ #define LSA_BODY_DUMMY ((void *) 1) /* * LSA entry life cycle * * LSA entries are created by ospf_originate_lsa() (for locally originated LSAs) * or ospf_install_lsa() (for LSAs received from neighbors). A regular (like * newly originated) LSA entry has defined lsa_body nad lsa.age < %LSA_MAXAGE. * When the LSA is requested to be flushed by ospf_flush_lsa(), the lsa.age is * set to %LSA_MAXAGE and flooded. Flush process is finished asynchronously, * when (at least) flooding is acknowledged by neighbors. This is detected in * ospf_update_lsadb(), then ospf_clear_lsa() is called to free the LSA body but * the LSA entry is kept. Such LSA does not formally exist, we keep an empty * entry (until regular timeout) to know inst_time and lsa.sn in the case of * later reorigination. After the timeout, LSA is removed by ospf_remove_lsa(). * * When LSA origination is requested (by ospf_originate_lsa()). but it is not * possible to do that immediately (because of MinLSInterval or because the * sequence number is wrapping), The new LSA is scheduled for later origination * in next_lsa_* fields of the LSA entry. The later origination is handled by * ospf_originate_next_lsa() called from ospf_update_lsadb(). We can see that * both real origination and final flush is asynchronous to ospf_originate_lsa() * and ospf_flush_lsa(). * * LSA entry therefore could be in three basic states: * R - regular (lsa.age < %LSA_MAXAGE, lsa_body != NULL) * F - flushing (lsa.age == %LSA_MAXAGE, lsa_body != NULL) * E - empty (lsa.age == %LSA_MAXAGE, lsa_body == NULL) * * And these states are doubled based on whether the next LSA is scheduled * (next_lsa_body != NULL, -n suffix) or not (next_lsa_body == NULL). We also * use X for a state of non-existentce. We have this basic state graph * (transitions from any state to R are omitted for clarity): * * X --> R ---> F ---> E --> X * | \ / | | * | \/ | | * | /\ | | * | / \ | | * Rn --> Fn --> En * * The transitions are: * * any state -> R - new LSA origination requested and executed * R -> Rn, F -> Fn, E -> En - new LSA origination requested and postponed * R -> Fn - new LSA origination requested, seqnum wrapping * Rn,Fn,En -> R - postponed LSA finally originated * R -> R - LSA refresh done * R -> Fn - LSA refresh with seqnum wrapping * R -> F, Rn -> Fn - LSA age timeout * R,Rn,Fn -> F, En -> E - LSA flush requested * F -> E, Fn -> En - LSA flush done (acknowledged) * E -> X - LSA real age timeout (or immediate for received LSA) * * The 'origination requested' and 'flush requested' transitions are triggered * and done by ospf_originate_lsa() and ospf_flush_lsa(), the rest is handled * asynchronously by ospf_update_lsadb(). * * The situation is significantly simpler for non-local (received) LSAs - there * is no postponed origination and after flushing is done, LSAs are immediately * removed, so it is just X -> R -> F -> X, or X -> F -> X (when MaxAge LSA is * received). * * There are also some special cases related to handling of received unknown * self-originated LSAs in ospf_advance_lsa(): * X -> F - LSA is received and immediately flushed * R,Rn -> Fn - LSA with MaxSeqNo received and flushed, current LSA scheduled */ #define LSA_M_BASIC 0 #define LSA_M_EXPORT 1 #define LSA_M_RTCALC 2 #define LSA_M_STALE 3 /* * LSA entry modes: * * LSA_M_BASIC - The LSA is explicitly originated using ospf_originate_lsa() and * explicitly flushed using ospf_flush_lsa(). When the LSA is changed, the * routing table calculation is scheduled. This is also the mode used for LSAs * received from neighbors. Example: Router-LSAs, Network-LSAs. * * LSA_M_EXPORT - like LSA_M_BASIC, but the routing table calculation does not * depend on the LSA. Therefore, the calculation is not scheduled when the LSA * is changed. Example: AS-external-LSAs for exported routes. * * LSA_M_RTCALC - The LSA has to be requested using ospf_originate_lsa() during * each routing table calculation, otherwise it is flushed automatically at the * end of the calculation. The LSA is a result of the calculation and not a * source for it. Therefore, the calculation is not scheduled when the LSA is * changed. Example: Summary-LSAs. * * LSA_M_STALE - Temporary state for LSA_M_RTCALC that is not requested during * the current routing table calculation. * * * Note that we do not schedule the routing table calculation when the age of * LSA_M_BASIC LSA is changed to MaxAge because of the sequence number wrapping, * As it will be switched back to a regular one ASAP. */ struct top_graph { pool *pool; /* Pool we allocate from */ slab *hash_slab; /* Slab for hash entries */ struct top_hash_entry **hash_table; /* Hashing (modelled a`la fib) */ uint ospf2; /* Whether it is for OSPFv2 or OSPFv3 */ uint hash_size; uint hash_order; uint hash_mask; uint hash_entries; uint hash_entries_min, hash_entries_max; }; struct ospf_new_lsa { u16 type; u8 mode; u32 dom; u32 id; u16 opts; u16 length; struct ospf_iface *ifa; struct ort *nf; }; struct top_graph *ospf_top_new(struct ospf_proto *p, pool *pool); void ospf_top_free(struct top_graph *f); struct top_hash_entry * ospf_install_lsa(struct ospf_proto *p, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body); struct top_hash_entry * ospf_originate_lsa(struct ospf_proto *p, struct ospf_new_lsa *lsa); void ospf_advance_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body); void ospf_flush_lsa(struct ospf_proto *p, struct top_hash_entry *en); void ospf_update_lsadb(struct ospf_proto *p); static inline void ospf_flush2_lsa(struct ospf_proto *p, struct top_hash_entry **en) { if (*en) { ospf_flush_lsa(p, *en); *en = NULL; } } void ospf_originate_sum_net_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric); void ospf_originate_sum_rt_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric, u32 options); 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); void ospf_rt_notify(struct proto *P, rtable *tbl, net *n, rte *new, rte *old, ea_list *attrs); void ospf_update_topology(struct ospf_proto *p); struct top_hash_entry *ospf_hash_find(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type); struct top_hash_entry *ospf_hash_get(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type); void ospf_hash_delete(struct top_graph *, struct top_hash_entry *); static inline struct top_hash_entry * ospf_hash_find_entry(struct top_graph *f, struct top_hash_entry *en) { return ospf_hash_find(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); } static inline struct top_hash_entry * ospf_hash_get_entry(struct top_graph *f, struct top_hash_entry *en) { return ospf_hash_get(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); } struct top_hash_entry * ospf_hash_find_rt(struct top_graph *f, u32 domain, u32 rtr); struct top_hash_entry * ospf_hash_find_rt3_first(struct top_graph *f, u32 domain, u32 rtr); struct top_hash_entry * ospf_hash_find_rt3_next(struct top_hash_entry *e); struct top_hash_entry * ospf_hash_find_net2(struct top_graph *f, u32 domain, u32 id); /* In OSPFv2, id is network IP prefix (lsa.id) while lsa.rt field is unknown In OSPFv3, id is lsa.rt of DR while nif is neighbor iface id (lsa.id) */ static inline struct top_hash_entry * ospf_hash_find_net(struct top_graph *f, u32 domain, u32 id, u32 nif) { return f->ospf2 ? ospf_hash_find_net2(f, domain, id) : ospf_hash_find(f, domain, nif, id, LSA_T_NET); } #endif /* _BIRD_OSPF_TOPOLOGY_H_ */