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bird 1.6.3

    1: /*
    2:  *      BIRD -- OSPF
    3:  *
    4:  *      (c) 2000--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_RT_H_
   12: #define _BIRD_OSPF_RT_H_
   13: 
   14: 
   15: #define ORT_NET 0
   16: #define ORT_ROUTER 1
   17: 
   18: typedef struct orta
   19: {
   20:   u8 type;			/* RTS_OSPF_* */
   21:   u8 nhs_reuse;			/* Whether nhs nodes can be reused during merging.
   22: 				   See a note in rt.c:add_cand() */
   23:   u32 options;
   24:   /*
   25:    * For ORT_ROUTER routes, options field are router-LSA style
   26:    * options, with V,E,B bits. In OSPFv2, ASBRs from another areas
   27:    * (that we know from rt-summary-lsa) have just ORTA_ASBR in
   28:    * options, their real options are unknown.
   29:    */
   30: #define ORTA_ASBR OPT_RT_E
   31: #define ORTA_ABR  OPT_RT_B
   32:   /*
   33:    * For ORT_NET routes, there are just several flags for external routes:
   34:    *
   35:    * ORTA_PREF for external routes means that the route is preferred in AS
   36:    * external route selection according to 16.4.1. - it is intra-area path using
   37:    * non-backbone area. In other words, the forwarding address (or ASBR if
   38:    * forwarding address is zero) is intra-area (type == RTS_OSPF) and its area
   39:    * is not a backbone.
   40:    *
   41:    * ORTA_NSSA means that the entry represents an NSSA route, and ORTA_PROP
   42:    * means that the NSSA route has propagate-bit set. These flags are used in
   43:    * NSSA translation.
   44:    */
   45: #define ORTA_PREF 0x80000000
   46: #define ORTA_NSSA 0x40000000
   47: #define ORTA_PROP 0x20000000
   48: 
   49:   u32 metric1;
   50:   u32 metric2;
   51:   u32 tag;
   52:   u32 rid;			/* Router ID of real advertising router */
   53:   struct ospf_area *oa;
   54:   struct ospf_area *voa;	/* Used when route is replaced in ospf_rt_sum_tr(),
   55: 				   NULL otherwise */
   56:   struct mpnh *nhs;		/* Next hops computed during SPF */
   57:   struct top_hash_entry *en;	/* LSA responsible for this orta */
   58: }
   59: orta;
   60: 
   61: typedef struct ort
   62: {
   63:   /*
   64:    * Most OSPF routing table entries are for computed OSPF routes, these have
   65:    * defined n.type. There are also few other cases: entries for configured area
   66:    * networks (these have area_net field set) and entries for external routes
   67:    * exported to OSPF (these have external_rte field set). These entries are
   68:    * kept even if they do not contain 'proper' rt entry. That is needed to keep
   69:    * allocated stable UID numbers (fn.uid), which are used as LSA IDs in OSPFv3
   70:    * (see fibnode_to_lsaid()) for related LSAs (network summary LSAs in the
   71:    * first case, external or NSSA LSAs in the second case). Entries for external
   72:    * routes also have a second purpose - to prevent NSSA translation of received
   73:    * NSSA routes if regular external routes were already originated for the same
   74:    * network (see check_nssa_lsa()).
   75:    *
   76:    * old_* values are here to represent the last route update. old_rta is cached
   77:    * (we keep reference), mainly for multipath nexthops.  old_rta == NULL means
   78:    * route was not in the last update, in that case other old_* values are not
   79:    * valid.
   80:    */
   81:   struct fib_node fn;
   82:   orta n;
   83:   u32 old_metric1, old_metric2, old_tag, old_rid;
   84:   rta *old_rta;
   85:   u8 external_rte;
   86:   u8 area_net;
   87:   u8 keep;
   88: }
   89: ort;
   90: 
   91: static inline int rt_is_nssa(ort *nf)
   92: { return nf->n.options & ORTA_NSSA; }
   93: 
   94: 
   95: /*
   96:  * Invariants for structs top_hash_entry (nodes of LSA db)
   97:  * enforced by SPF calculation for final nodes (color == INSPF):
   98:  * - only router, network and AS-external LSAs
   99:  * - lsa.age < LSA_MAXAGE
  100:  * - dist < LSINFINITY (or 2*LSINFINITY for ext-LSAs)
  101:  * - nhs is non-NULL unless the node is oa->rt (calculating router itself)
  102:  * - beware, nhs is not valid after SPF calculation
  103:  *
  104:  * Invariants for structs orta nodes of fib tables po->rtf, oa->rtr:
  105:  * - nodes may be invalid (n.type == 0), in that case other invariants don't hold
  106:  * - n.metric1 may be at most a small multiple of LSINFINITY,
  107:  *   therefore sums do not overflow
  108:  * - n.oa is always non-NULL
  109:  * - n.nhs is always non-NULL unless it is configured stubnet
  110:  * - n.en is non-NULL for external routes, NULL for intra/inter area routes.
  111:  * - oa->rtr does not contain calculating router itself
  112:  *
  113:  * There are four types of nexthops in nhs fields:
  114:  * - gateway nexthops (non-NULL iface, gw != IPA_NONE)
  115:  * - device nexthops (non-NULL iface, gw == IPA_NONE)
  116:  * - dummy vlink nexthops (NULL iface, gw == IPA_NONE)
  117:  * - configured stubnets (nhs is NULL, only RTS_OSPF orta nodes in po->rtf)
  118:  *
  119:  * Dummy vlink nexthops and configured stubnets cannot be mixed with
  120:  * regular ones, nhs field contains either list of gateway+device nodes,
  121:  * one vlink node, or NULL for configured stubnet.
  122:  *
  123:  * Dummy vlink nexthops can appear in both network (rtf) and backbone area router
  124:  * (rtr) tables for regular and inter-area routes, but only if areano > 1. They are
  125:  * replaced in ospf_rt_sum_tr() and removed in ospf_rt_abr1(), therefore cannot
  126:  * appear in ASBR pre-selection and external routes processing.
  127:  */
  128: 
  129: void ospf_rt_spf(struct ospf_proto *p);
  130: void ospf_rt_initort(struct fib_node *fn);
  131: 
  132: 
  133: #endif /* _BIRD_OSPF_RT_H_ */