We need to flush learned external LSAs a bit later than other LSAs (after first feed after end of the graceful restart) to avoid flap of external routes.
233 lines
10 KiB
C
233 lines
10 KiB
C
/*
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* BIRD -- OSPF
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*
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* (c) 1999--2004 Ondrej Filip <feela@network.cz>
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* (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>
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* (c) 2009--2014 CZ.NIC z.s.p.o.
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_OSPF_TOPOLOGY_H_
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#define _BIRD_OSPF_TOPOLOGY_H_
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struct top_hash_entry
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{ /* Index for fast mapping (type,rtrid,LSid)->vertex */
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snode n;
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node cn; /* For adding into list of candidates
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in intra-area routing table calculation */
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struct top_hash_entry *next; /* Next in hash chain */
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struct ospf_lsa_header lsa;
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u16 lsa_type; /* lsa.type processed and converted to common values (LSA_T_*) */
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u16 init_age; /* Initial value for lsa.age during inst_time */
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u32 domain; /* Area ID for area-wide LSAs, Iface ID for link-wide LSAs */
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// struct ospf_area *oa;
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void *lsa_body; /* May be NULL if LSA was flushed but hash entry was kept */
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void *next_lsa_body; /* For postponed LSA origination */
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u16 next_lsa_blen; /* For postponed LSA origination */
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u16 next_lsa_opts; /* For postponed LSA origination */
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btime inst_time; /* Time of installation into DB */
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struct ort *nf; /* Reference fibnode for sum and ext LSAs, NULL for otherwise */
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struct nexthop *nhs; /* Computed nexthops - valid only in ospf_rt_spf() */
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ip_addr lb; /* In OSPFv2, link back address. In OSPFv3, any global address in the area useful for vlinks */
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u32 lb_id; /* Interface ID of link back iface (for bcast or NBMA networks) */
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u32 dist; /* Distance from the root */
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int ret_count; /* Number of retransmission lists referencing the entry */
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u8 gr_dirty; /* Local LSA received during GR, will be removed unless reoriginated */
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u8 color;
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#define OUTSPF 0
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#define CANDIDATE 1
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#define INSPF 2
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u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/
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u8 nhs_reuse; /* Whether nhs nodes can be reused during merging.
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See a note in rt.c:add_cand() */
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};
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/* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */
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#define LSA_BODY_DUMMY ((void *) 1)
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/*
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* LSA entry life cycle
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*
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* LSA entries are created by ospf_originate_lsa() (for locally originated LSAs)
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* or ospf_install_lsa() (for LSAs received from neighbors). A regular (like
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* newly originated) LSA entry has defined lsa_body nad lsa.age < %LSA_MAXAGE.
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* When the LSA is requested to be flushed by ospf_flush_lsa(), the lsa.age is
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* set to %LSA_MAXAGE and flooded. Flush process is finished asynchronously,
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* when (at least) flooding is acknowledged by neighbors. This is detected in
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* ospf_update_lsadb(), then ospf_clear_lsa() is called to free the LSA body but
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* the LSA entry is kept. Such LSA does not formally exist, we keep an empty
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* entry (until regular timeout) to know inst_time and lsa.sn in the case of
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* later reorigination. After the timeout, LSA is removed by ospf_remove_lsa().
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*
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* When LSA origination is requested (by ospf_originate_lsa()). but it is not
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* possible to do that immediately (because of MinLSInterval or because the
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* sequence number is wrapping), The new LSA is scheduled for later origination
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* in next_lsa_* fields of the LSA entry. The later origination is handled by
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* ospf_originate_next_lsa() called from ospf_update_lsadb(). We can see that
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* both real origination and final flush is asynchronous to ospf_originate_lsa()
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* and ospf_flush_lsa().
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*
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* LSA entry therefore could be in three basic states:
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* R - regular (lsa.age < %LSA_MAXAGE, lsa_body != NULL)
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* F - flushing (lsa.age == %LSA_MAXAGE, lsa_body != NULL)
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* E - empty (lsa.age == %LSA_MAXAGE, lsa_body == NULL)
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*
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* And these states are doubled based on whether the next LSA is scheduled
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* (next_lsa_body != NULL, -n suffix) or not (next_lsa_body == NULL). We also
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* use X for a state of non-existentce. We have this basic state graph
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* (transitions from any state to R are omitted for clarity):
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*
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* X --> R ---> F ---> E --> X
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* | \ / | |
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* | \/ | |
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* | /\ | |
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* | / \ | |
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* Rn --> Fn --> En
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*
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* The transitions are:
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*
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* any state -> R - new LSA origination requested and executed
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* R -> Rn, F -> Fn, E -> En - new LSA origination requested and postponed
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* R -> Fn - new LSA origination requested, seqnum wrapping
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* Rn,Fn,En -> R - postponed LSA finally originated
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* R -> R - LSA refresh done
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* R -> Fn - LSA refresh with seqnum wrapping
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* R -> F, Rn -> Fn - LSA age timeout
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* R,Rn,Fn -> F, En -> E - LSA flush requested
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* F -> E, Fn -> En - LSA flush done (acknowledged)
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* E -> X - LSA real age timeout (or immediate for received LSA)
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*
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* The 'origination requested' and 'flush requested' transitions are triggered
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* and done by ospf_originate_lsa() and ospf_flush_lsa(), the rest is handled
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* asynchronously by ospf_update_lsadb().
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*
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* The situation is significantly simpler for non-local (received) LSAs - there
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* is no postponed origination and after flushing is done, LSAs are immediately
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* removed, so it is just X -> R -> F -> X, or X -> F -> X (when MaxAge LSA is
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* received).
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*
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* There are also some special cases related to handling of received unknown
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* self-originated LSAs in ospf_advance_lsa():
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* X -> F - LSA is received and immediately flushed
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* R,Rn -> Fn - LSA with MaxSeqNo received and flushed, current LSA scheduled
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*/
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#define LSA_M_BASIC 0
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#define LSA_M_EXPORT 1
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#define LSA_M_RTCALC 2
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#define LSA_M_EXPORT_STALE 3
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#define LSA_M_RTCALC_STALE 4
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/*
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* LSA entry modes:
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*
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* LSA_M_BASIC - The LSA is explicitly originated using ospf_originate_lsa() and
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* explicitly flushed using ospf_flush_lsa(). When the LSA is changed, the
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* routing table calculation is scheduled. This is also the mode used for LSAs
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* received from neighbors. Example: Router-LSAs, Network-LSAs.
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*
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* LSA_M_EXPORT - The LSA is originated using ospf_originate_lsa() as a
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* consequence of route export to the OSPF instance. It has to be reoriginated
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* during each channel feed, otherwise it is flushed automatically at the end of
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* the feed. May be originated and flushed asynchronously. Also, routing table
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* calculation does not depend on the LSA. Therefore, the routing table
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* calculation is not scheduled when the LSA is changed. Example:
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* AS-external-LSAs for exported routes.
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*
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* LSA_M_RTCALC - The LSA has to be requested using ospf_originate_lsa() during
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* each routing table calculation, otherwise it is flushed automatically at the
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* end of the calculation. The LSA is a result of the calculation and not a
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* source for it. Therefore, the calculation is not scheduled when the LSA is
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* changed. Example: Summary-LSAs.
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*
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* LSA_M_EXPORT_STALE - Temporary state for LSA_M_EXPORT that is not requested
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* during current external route feed.
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*
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* LSA_M_RTCALC_STALE - Temporary state for LSA_M_RTCALC that is not requested
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* during current routing table calculation.
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*
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*
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* Note that we do not schedule the routing table calculation when the age of
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* LSA_M_BASIC LSA is changed to MaxAge because of the sequence number wrapping,
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* As it will be switched back to a regular one ASAP.
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*/
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struct top_graph
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{
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pool *pool; /* Pool we allocate from */
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slab *hash_slab; /* Slab for hash entries */
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struct top_hash_entry **hash_table; /* Hashing (modelled a`la fib) */
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uint ospf2; /* Whether it is for OSPFv2 or OSPFv3 */
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uint hash_size;
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uint hash_order;
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uint hash_mask;
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uint hash_entries;
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uint hash_entries_min, hash_entries_max;
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};
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struct ospf_new_lsa
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{
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u16 type;
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u8 mode;
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u32 dom;
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u32 id;
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u16 opts;
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u16 length;
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struct ospf_iface *ifa;
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struct ort *nf;
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};
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struct top_graph *ospf_top_new(struct ospf_proto *p, pool *pool);
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void ospf_top_free(struct top_graph *f);
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struct top_hash_entry * ospf_install_lsa(struct ospf_proto *p, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
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struct top_hash_entry * ospf_originate_lsa(struct ospf_proto *p, struct ospf_new_lsa *lsa);
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void ospf_advance_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_lsa_header *lsa, u32 type, u32 domain, void *body);
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void ospf_flush_lsa(struct ospf_proto *p, struct top_hash_entry *en);
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void ospf_update_lsadb(struct ospf_proto *p);
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void ospf_feed_begin(struct channel *C, int initial);
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void ospf_feed_end(struct channel *C);
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static inline void ospf_flush2_lsa(struct ospf_proto *p, struct top_hash_entry **en)
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{ if (*en) { ospf_flush_lsa(p, *en); *en = NULL; } }
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void ospf_originate_sum_net_lsa(struct ospf_proto *p, struct ospf_area *oa, ort *nf, int metric);
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void ospf_originate_sum_rt_lsa(struct ospf_proto *p, struct ospf_area *oa, u32 drid, int metric, u32 options);
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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);
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void ospf_originate_gr_lsa(struct ospf_proto *p, struct ospf_iface *ifa);
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void ospf_rt_notify(struct proto *P, struct channel *ch, net *n, rte *new, rte *old);
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void ospf_update_topology(struct ospf_proto *p);
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struct top_hash_entry *ospf_hash_find(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
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struct top_hash_entry *ospf_hash_get(struct top_graph *, u32 domain, u32 lsa, u32 rtr, u32 type);
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void ospf_hash_delete(struct top_graph *, struct top_hash_entry *);
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static inline struct top_hash_entry * ospf_hash_find_entry(struct top_graph *f, struct top_hash_entry *en)
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{ return ospf_hash_find(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
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static inline struct top_hash_entry * ospf_hash_get_entry(struct top_graph *f, struct top_hash_entry *en)
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{ return ospf_hash_get(f, en->domain, en->lsa.id, en->lsa.rt, en->lsa_type); }
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struct top_hash_entry * ospf_hash_find_rt(struct top_graph *f, u32 domain, u32 rtr);
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struct top_hash_entry * ospf_hash_find_rt3_first(struct top_graph *f, u32 domain, u32 rtr);
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struct top_hash_entry * ospf_hash_find_rt3_next(struct top_hash_entry *e);
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struct top_hash_entry * ospf_hash_find_net2(struct top_graph *f, u32 domain, u32 id);
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/* In OSPFv2, id is network IP prefix (lsa.id) while lsa.rt field is unknown
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In OSPFv3, id is lsa.rt of DR while nif is neighbor iface id (lsa.id) */
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static inline struct top_hash_entry *
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ospf_hash_find_net(struct top_graph *f, u32 domain, u32 id, u32 nif)
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{
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return f->ospf2 ?
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ospf_hash_find_net2(f, domain, id) :
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ospf_hash_find(f, domain, nif, id, LSA_T_NET);
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}
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#endif /* _BIRD_OSPF_TOPOLOGY_H_ */
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