bird/proto/ospf/topology.h
Jan Maria Matejka 13c0be19d3 Nest: Removing separate tmpa from route propagation
This is a fundamental change of an original (1999) concept of route
processing inside BIRD. During import/export, there was a temporary
ea_list created which was to be used instead of the another one inside
the route itself.

This led to some confusion, quirks, and strange filter code that handled
extended route attributes. Dropping it now.

The protocol interface has changed in an uniform way -- the
`struct ea_list *attrs` argument has been removed from store_tmp_attrs(),
import_control(), rt_notify() and get_route_info().
2018-05-30 17:08:49 +02:00

221 lines
9.5 KiB
C

/*
* BIRD -- OSPF
*
* (c) 1999--2004 Ondrej Filip <feela@network.cz>
* (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>
* (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 */
btime inst_time; /* Time of installation into DB */
struct ort *nf; /* Reference fibnode for sum and ext LSAs, NULL for otherwise */
struct nexthop *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:add_cand() */
};
/* 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, u32 drid, 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, struct channel *ch, net *n, rte *new, rte *old);
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_ */