Annotation of embedaddon/bird2/proto/ospf/topology.h, revision 1.1.1.1
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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