/* * BIRD -- OSPF * * (c) 2000--2004 Ondrej Filip * (c) 2009--2014 Ondrej Zajicek * (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 mpnh *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_ */