Annotation of embedaddon/bird2/proto/ospf/topology.h, revision 1.1
1.1 ! misho 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: btime inst_time; /* Time of installation into DB */
! 30: struct ort *nf; /* Reference fibnode for sum and ext LSAs, NULL for otherwise */
! 31: struct nexthop *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 gr_dirty; /* Local LSA received during GR, will be removed unless reoriginated */
! 37: u8 color;
! 38: #define OUTSPF 0
! 39: #define CANDIDATE 1
! 40: #define INSPF 2
! 41: u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/
! 42: u8 nhs_reuse; /* Whether nhs nodes can be reused during merging.
! 43: See a note in rt.c:add_cand() */
! 44: };
! 45:
! 46:
! 47: /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */
! 48: #define LSA_BODY_DUMMY ((void *) 1)
! 49:
! 50: /*
! 51: * LSA entry life cycle
! 52: *
! 53: * LSA entries are created by ospf_originate_lsa() (for locally originated LSAs)
! 54: * or ospf_install_lsa() (for LSAs received from neighbors). A regular (like
! 55: * newly originated) LSA entry has defined lsa_body nad lsa.age < %LSA_MAXAGE.
! 56: * When the LSA is requested to be flushed by ospf_flush_lsa(), the lsa.age is
! 57: * set to %LSA_MAXAGE and flooded. Flush process is finished asynchronously,
! 58: * when (at least) flooding is acknowledged by neighbors. This is detected in
! 59: * ospf_update_lsadb(), then ospf_clear_lsa() is called to free the LSA body but
! 60: * the LSA entry is kept. Such LSA does not formally exist, we keep an empty
! 61: * entry (until regular timeout) to know inst_time and lsa.sn in the case of
! 62: * later reorigination. After the timeout, LSA is removed by ospf_remove_lsa().
! 63: *
! 64: * When LSA origination is requested (by ospf_originate_lsa()). but it is not
! 65: * possible to do that immediately (because of MinLSInterval or because the
! 66: * sequence number is wrapping), The new LSA is scheduled for later origination
! 67: * in next_lsa_* fields of the LSA entry. The later origination is handled by
! 68: * ospf_originate_next_lsa() called from ospf_update_lsadb(). We can see that
! 69: * both real origination and final flush is asynchronous to ospf_originate_lsa()
! 70: * and ospf_flush_lsa().
! 71: *
! 72: * LSA entry therefore could be in three basic states:
! 73: * R - regular (lsa.age < %LSA_MAXAGE, lsa_body != NULL)
! 74: * F - flushing (lsa.age == %LSA_MAXAGE, lsa_body != NULL)
! 75: * E - empty (lsa.age == %LSA_MAXAGE, lsa_body == NULL)
! 76: *
! 77: * And these states are doubled based on whether the next LSA is scheduled
! 78: * (next_lsa_body != NULL, -n suffix) or not (next_lsa_body == NULL). We also
! 79: * use X for a state of non-existentce. We have this basic state graph
! 80: * (transitions from any state to R are omitted for clarity):
! 81: *
! 82: * X --> R ---> F ---> E --> X
! 83: * | \ / | |
! 84: * | \/ | |
! 85: * | /\ | |
! 86: * | / \ | |
! 87: * Rn --> Fn --> En
! 88: *
! 89: * The transitions are:
! 90: *
! 91: * any state -> R - new LSA origination requested and executed
! 92: * R -> Rn, F -> Fn, E -> En - new LSA origination requested and postponed
! 93: * R -> Fn - new LSA origination requested, seqnum wrapping
! 94: * Rn,Fn,En -> R - postponed LSA finally originated
! 95: * R -> R - LSA refresh done
! 96: * R -> Fn - LSA refresh with seqnum wrapping
! 97: * R -> F, Rn -> Fn - LSA age timeout
! 98: * R,Rn,Fn -> F, En -> E - LSA flush requested
! 99: * F -> E, Fn -> En - LSA flush done (acknowledged)
! 100: * E -> X - LSA real age timeout (or immediate for received LSA)
! 101: *
! 102: * The 'origination requested' and 'flush requested' transitions are triggered
! 103: * and done by ospf_originate_lsa() and ospf_flush_lsa(), the rest is handled
! 104: * asynchronously by ospf_update_lsadb().
! 105: *
! 106: * The situation is significantly simpler for non-local (received) LSAs - there
! 107: * is no postponed origination and after flushing is done, LSAs are immediately
! 108: * removed, so it is just X -> R -> F -> X, or X -> F -> X (when MaxAge LSA is
! 109: * received).
! 110: *
! 111: * There are also some special cases related to handling of received unknown
! 112: * self-originated LSAs in ospf_advance_lsa():
! 113: * X -> F - LSA is received and immediately flushed
! 114: * R,Rn -> Fn - LSA with MaxSeqNo received and flushed, current LSA scheduled
! 115: */
! 116:
! 117:
! 118: #define LSA_M_BASIC 0
! 119: #define LSA_M_EXPORT 1
! 120: #define LSA_M_RTCALC 2
! 121: #define LSA_M_EXPORT_STALE 3
! 122: #define LSA_M_RTCALC_STALE 4
! 123:
! 124: /*
! 125: * LSA entry modes:
! 126: *
! 127: * LSA_M_BASIC - The LSA is explicitly originated using ospf_originate_lsa() and
! 128: * explicitly flushed using ospf_flush_lsa(). When the LSA is changed, the
! 129: * routing table calculation is scheduled. This is also the mode used for LSAs
! 130: * received from neighbors. Example: Router-LSAs, Network-LSAs.
! 131: *
! 132: * LSA_M_EXPORT - The LSA is originated using ospf_originate_lsa() as a
! 133: * consequence of route export to the OSPF instance. It has to be reoriginated
! 134: * during each channel feed, otherwise it is flushed automatically at the end of
! 135: * the feed. May be originated and flushed asynchronously. Also, routing table
! 136: * calculation does not depend on the LSA. Therefore, the routing table
! 137: * calculation is not scheduled when the LSA is changed. Example:
! 138: * AS-external-LSAs for exported routes.
! 139: *
! 140: * LSA_M_RTCALC - The LSA has to be requested using ospf_originate_lsa() during
! 141: * each routing table calculation, otherwise it is flushed automatically at the
! 142: * end of the calculation. The LSA is a result of the calculation and not a
! 143: * source for it. Therefore, the calculation is not scheduled when the LSA is
! 144: * changed. Example: Summary-LSAs.
! 145: *
! 146: * LSA_M_EXPORT_STALE - Temporary state for LSA_M_EXPORT that is not requested
! 147: * during current external route feed.
! 148: *
! 149: * LSA_M_RTCALC_STALE - Temporary state for LSA_M_RTCALC that is not requested
! 150: * during current routing table calculation.
! 151: *
! 152: *
! 153: * Note that we do not schedule the routing table calculation when the age of
! 154: * LSA_M_BASIC LSA is changed to MaxAge because of the sequence number wrapping,
! 155: * As it will be switched back to a regular one ASAP.
! 156: */
! 157:
! 158:
! 159: struct top_graph
! 160: {
! 161: pool *pool; /* Pool we allocate from */
! 162: slab *hash_slab; /* Slab for hash entries */
! 163: struct top_hash_entry **hash_table; /* Hashing (modelled a`la fib) */
! 164: uint ospf2; /* Whether it is for OSPFv2 or OSPFv3 */
! 165: uint hash_size;
! 166: uint hash_order;
! 167: uint hash_mask;
! 168: uint hash_entries;
! 169: uint hash_entries_min, hash_entries_max;
! 170: };
! 171:
! 172: struct ospf_new_lsa
! 173: {
! 174: u16 type;
! 175: u8 mode;
! 176: u32 dom;
! 177: u32 id;
! 178: u16 opts;
! 179: u16 length;
! 180: struct ospf_iface *ifa;
! 181: struct ort *nf;
! 182: };
! 183:
! 184: struct top_graph *ospf_top_new(struct ospf_proto *p, pool *pool);
! 185: void ospf_top_free(struct top_graph *f);
! 186:
! 187: struct top_hash_entry * ospf_install_lsa(struct ospf_proto *p, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
! 188: struct top_hash_entry * ospf_originate_lsa(struct ospf_proto *p, struct ospf_new_lsa *lsa);
! 189: void ospf_advance_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
! 190: void ospf_flush_lsa(struct ospf_proto *p, struct top_hash_entry *en);
! 191: void ospf_update_lsadb(struct ospf_proto *p);
! 192: void ospf_feed_begin(struct channel *C, int initial);
! 193: void ospf_feed_end(struct channel *C);
! 194:
! 195: static inline void ospf_flush2_lsa(struct ospf_proto *p, struct top_hash_entry **en)
! 196: { if (*en) { ospf_flush_lsa(p, *en); *en = NULL; } }
! 197:
! 198: void ospf_originate_sum_net_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric);
! 199: void ospf_originate_sum_rt_lsa(struct ospf_proto *p, struct ospf_area *oa, u32 drid, int metric, u32 options);
! 200: 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, int dn);
! 201: void ospf_originate_gr_lsa(struct ospf_proto *p, struct ospf_iface *ifa);
! 202:
! 203: void ospf_rt_notify(struct proto *P, struct channel *ch, net *n, rte *new, rte *old);
! 204: void ospf_update_topology(struct ospf_proto *p);
! 205:
! 206: struct top_hash_entry *ospf_hash_find(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
! 207: struct top_hash_entry *ospf_hash_get(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
! 208: void ospf_hash_delete(struct top_graph *, struct top_hash_entry *);
! 209:
! 210: static inline struct top_hash_entry * ospf_hash_find_entry(struct top_graph *f, struct top_hash_entry *en)
! 211: { return ospf_hash_find(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
! 212:
! 213: static inline struct top_hash_entry * ospf_hash_get_entry(struct top_graph *f, struct top_hash_entry *en)
! 214: { return ospf_hash_get(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
! 215:
! 216: struct top_hash_entry * ospf_hash_find_rt(struct top_graph *f, u32 domain, u32 rtr);
! 217: struct top_hash_entry * ospf_hash_find_rt3_first(struct top_graph *f, u32 domain, u32 rtr);
! 218: struct top_hash_entry * ospf_hash_find_rt3_next(struct top_hash_entry *e);
! 219:
! 220: struct top_hash_entry * ospf_hash_find_net2(struct top_graph *f, u32 domain, u32 id);
! 221:
! 222: /* In OSPFv2, id is network IP prefix (lsa.id) while lsa.rt field is unknown
! 223: In OSPFv3, id is lsa.rt of DR while nif is neighbor iface id (lsa.id) */
! 224: static inline struct top_hash_entry *
! 225: ospf_hash_find_net(struct top_graph *f, u32 domain, u32 id, u32 nif)
! 226: {
! 227: return f->ospf2 ?
! 228: ospf_hash_find_net2(f, domain, id) :
! 229: ospf_hash_find(f, domain, nif, id, LSA_T_NET);
! 230: }
! 231:
! 232:
! 233: #endif /* _BIRD_OSPF_TOPOLOGY_H_ */
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