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/*
* BIRD -- OSPF
*
* (c) 2000--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_RT_H_
#define _BIRD_OSPF_RT_H_
#define ORT_NET 0
#define ORT_ROUTER 1
typedef struct orta
{
u8 type; /* RTS_OSPF_* */
u8 nhs_reuse; /* Whether nhs nodes can be reused during merging.
See a note in rt.c:add_cand() */
u32 options;
/*
* For ORT_ROUTER routes, options field are router-LSA style
* options, with V,E,B bits. In OSPFv2, ASBRs from another areas
* (that we know from rt-summary-lsa) have just ORTA_ASBR in
* options, their real options are unknown.
*/
#define ORTA_ASBR OPT_RT_E
#define ORTA_ABR OPT_RT_B
/*
* For ORT_NET routes, there are just several flags for external routes:
*
* ORTA_PREF for external routes means that the route is preferred in AS
* external route selection according to 16.4.1. - it is intra-area path using
* non-backbone area. In other words, the forwarding address (or ASBR if
* forwarding address is zero) is intra-area (type == RTS_OSPF) and its area
* is not a backbone.
*
* ORTA_NSSA means that the entry represents an NSSA route, and ORTA_PROP
* means that the NSSA route has propagate-bit set. These flags are used in
* NSSA translation.
*/
#define ORTA_PREF 0x80000000
#define ORTA_NSSA 0x40000000
#define ORTA_PROP 0x20000000
u32 metric1;
u32 metric2;
u32 tag;
u32 rid; /* Router ID of real advertising router */
struct ospf_area *oa;
struct ospf_area *voa; /* Used when route is replaced in ospf_rt_sum_tr(),
NULL otherwise */
struct nexthop *nhs; /* Next hops computed during SPF */
struct top_hash_entry *en; /* LSA responsible for this orta */
}
orta;
typedef struct ort
{
/*
* Most OSPF routing table entries are for computed OSPF routes, these have
* defined n.type. There are also few other cases: entries for configured area
* networks (these have area_net field set) and entries for external routes
* exported to OSPF (these have external_rte field set). These entries are
* kept even if they do not contain 'proper' rt entry. That is needed to keep
* allocated stable UID numbers (fn.uid), which are used as LSA IDs in OSPFv3
* (see fibnode_to_lsaid()) for related LSAs (network summary LSAs in the
* first case, external or NSSA LSAs in the second case). Entries for external
* routes also have a second purpose - to prevent NSSA translation of received
* NSSA routes if regular external routes were already originated for the same
* network (see check_nssa_lsa()).
*
* old_* values are here to represent the last route update. old_rta is cached
* (we keep reference), mainly for multipath nexthops. old_rta == NULL means
* route was not in the last update, in that case other old_* values are not
* valid.
*/
orta n;
u32 old_metric1, old_metric2, old_tag, old_rid;
rta *old_rta;
u32 lsa_id;
u8 external_rte;
u8 area_net;
struct fib_node fn;
}
ort;
static inline int rt_is_nssa(ort *nf)
{ return nf->n.options & ORTA_NSSA; }
/*
* Invariants for structs top_hash_entry (nodes of LSA db)
* enforced by SPF calculation for final nodes (color == INSPF):
* - only router, network and AS-external LSAs
* - lsa.age < LSA_MAXAGE
* - dist < LSINFINITY (or 2*LSINFINITY for ext-LSAs)
* - nhs is non-NULL unless the node is oa->rt (calculating router itself)
* - beware, nhs is not valid after SPF calculation
*
* Invariants for structs orta nodes of fib tables po->rtf, oa->rtr:
* - nodes may be invalid (n.type == 0), in that case other invariants don't hold
* - n.metric1 may be at most a small multiple of LSINFINITY,
* therefore sums do not overflow
* - n.oa is always non-NULL
* - n.nhs is always non-NULL unless it is configured stubnet
* - n.en is non-NULL for external routes, NULL for intra/inter area routes.
* - oa->rtr does not contain calculating router itself
*
* There are four types of nexthops in nhs fields:
* - gateway nexthops (non-NULL iface, gw != IPA_NONE)
* - device nexthops (non-NULL iface, gw == IPA_NONE)
* - dummy vlink nexthops (NULL iface, gw == IPA_NONE)
* - configured stubnets (nhs is NULL, only RTS_OSPF orta nodes in po->rtf)
*
* Dummy vlink nexthops and configured stubnets cannot be mixed with
* regular ones, nhs field contains either list of gateway+device nodes,
* one vlink node, or NULL for configured stubnet.
*
* Dummy vlink nexthops can appear in both network (rtf) and backbone area router
* (rtr) tables for regular and inter-area routes, but only if areano > 1. They are
* replaced in ospf_rt_sum_tr() and removed in ospf_rt_abr1(), therefore cannot
* appear in ASBR pre-selection and external routes processing.
*/
void ospf_rt_spf(struct ospf_proto *p);
void ospf_rt_initort(struct fib_node *fn);
#endif /* _BIRD_OSPF_RT_H_ */
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