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iof-bird-daemon / proto / ospf / rt.h @ 145368f5

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/*
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 *      BIRD -- OSPF
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 *
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 *      (c) 2000--2004 Ondrej Filip <feela@network.cz>
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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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 */
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#ifndef _BIRD_OSPF_RT_H_
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#define _BIRD_OSPF_RT_H_
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#define ORT_UNDEF -1
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#define ORT_ROUTER 1
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#define ORT_NET 0
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typedef struct orta
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{
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  u8 type;                        /* RTS_OSPF_* */
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  u8 nhs_reuse;                        /* Whether nhs nodes can be reused during merging */
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  u32 options;
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  /*
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   * For ORT_ROUTER routes, options field are router-LSA style
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   * options, with V,E,B bits. In OSPFv2, ASBRs from another areas
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   * (that we know from rt-summary-lsa) have just ORTA_ASBR in
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   * options, their real options are unknown.
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   */
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#define ORTA_ASBR OPT_RT_E
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#define ORTA_ABR  OPT_RT_B
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  /*
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   * For ORT_NET routes, the field is almost unused with one
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   * exception: ORTA_PREF for external routes means that the route is
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   * preferred in AS external route selection according to 16.4.1. -
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   * it is intra-area path using non-backbone area. In other words,
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   * the forwarding address (or ASBR if forwarding address is zero) is
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   * intra-area (type == RTS_OSPF) and its area is not a backbone.
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   */
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#define ORTA_PREF 0x80000000
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#define ORTA_NSSA 0x40000000
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#define ORTA_PROP 0x20000000
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  u32 metric1;
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  u32 metric2;
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  u32 tag;
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  u32 rid;                        /* Router ID of real advertising router */
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  struct ospf_area *oa;
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  struct ospf_area *voa;        /* Used when route is replaced in ospf_rt_sum_tr(),
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                                   NULL otherwise */
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  struct mpnh *nhs;                /* Next hops computed during SPF */
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  struct top_hash_entry *en;        /* LSA responsible for this orta */
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}
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orta;
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typedef struct ort
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{
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  /*
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   * We use fn.x0 to mark persistent rt entries, that are needed for summary
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   * LSAs that don't have 'proper' rt entry (area networks + default to stubs)
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   * to keep uid stable (used for LSA ID in OSPFv3 - see fibnode_to_lsaid()).
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   *
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   * We use fn.x1 to note whether the external route was originated
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   * from the route export (in ospf_rt_notify()) or from the NSSA
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   * route translation (in check_nssa_lsa()).
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   *
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   * old_* values are here to represent the last route update. old_rta
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   * is cached (we keep reference), mainly for multipath nexthops.
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   * old_rta == NULL means route wasn not in the last update, in that
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   * case other old_* values are not valid.
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   */
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  struct fib_node fn;
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  orta n;
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  u32 old_metric1, old_metric2, old_tag, old_rid;
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  rta *old_rta;
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}
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ort;
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static inline int rt_is_nssa(ort *nf)
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{ return nf->n.options & ORTA_NSSA; }
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#define EXT_EXPORT 1
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#define EXT_NSSA 2
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/*
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 * Invariants for structs top_hash_entry (nodes of LSA db)
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 * enforced by SPF calculation for final nodes (color == INSPF):
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 * - only router, network and AS-external LSAs
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 * - lsa.age < LSA_MAXAGE
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 * - dist < LSINFINITY (or 2*LSINFINITY for ext-LSAs)
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 * - nhs is non-NULL unless the node is oa->rt (calculating router itself)
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 * - beware, nhs is not valid after SPF calculation
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 *
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 * Invariants for structs orta nodes of fib tables po->rtf, oa->rtr:
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 * - nodes may be invalid (fn.type == 0), in that case other invariants don't hold
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 * - n.metric1 may be at most a small multiple of LSINFINITY,
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 *   therefore sums do not overflow
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 * - n.oa is always non-NULL
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 * - n.nhs is always non-NULL unless it is configured stubnet
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 * - n.en is non-NULL for external routes, NULL for intra/inter area routes.
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 * - oa->rtr does not contain calculating router itself
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 *
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 * There are four types of nexthops in nhs fields:
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 * - gateway nexthops (non-NULL iface, gw != IPA_NONE)
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 * - device nexthops (non-NULL iface, gw == IPA_NONE)
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 * - dummy vlink nexthops (NULL iface, gw == IPA_NONE)
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 * - configured stubnets (nhs is NULL, only RTS_OSPF orta nodes in po->rtf)
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 *
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 * Dummy vlink nexthops and configured stubnets cannot be mixed with
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 * regular ones, nhs field contains either list of gateway+device nodes,
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 * one vlink node, or NULL for configured stubnet.
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 *
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 * Dummy vlink nexthops can appear in both network (rtf) and backbone area router
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 * (rtr) tables for regular and inter-area routes, but only if areano > 1. They are
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 * replaced in ospf_rt_sum_tr() and removed in ospf_rt_abr1(), therefore cannot
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 * appear in ASBR pre-selection and external routes processing.
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 */
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void ospf_rt_spf(struct proto_ospf *po);
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void ospf_rt_initort(struct fib_node *fn);
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#endif /* _BIRD_OSPF_RT_H_ */