145368f547
Fixes cases where the same network or external route are propagated by several OSPF routes and some other corner cases in next hop construction and ECMP. Allows to specify whether external routes should be merged. Thanks to Peter Christensen for the original patch.
122 lines
4.2 KiB
C
122 lines
4.2 KiB
C
/*
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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_ */
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