Statistics
| Branch: | Revision:

iof-bird-daemon / proto / ospf / rt.h @ a7a7372a

History | View | Annotate | Download (4.84 KB)

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
  u32 options;
23
  /*
24
   * For ORT_ROUTER routes, options field are router-LSA style
25
   * options, with V,E,B bits. In OSPFv2, ASBRs from another areas
26
   * (that we know from rt-summary-lsa) have just ORTA_ASBR in
27
   * options, their real options are unknown.
28
   */
29
#define ORTA_ASBR OPT_RT_E
30
#define ORTA_ABR  OPT_RT_B
31
  /*
32
   * For ORT_NET routes, there are just several flags for external routes:
33
   *
34
   * ORTA_PREF for external routes means that the route is preferred in AS
35
   * external route selection according to 16.4.1. - it is intra-area path using
36
   * non-backbone area. In other words, the forwarding address (or ASBR if
37
   * forwarding address is zero) is intra-area (type == RTS_OSPF) and its area
38
   * is not a backbone.
39
   *
40
   * ORTA_NSSA means that the entry represents an NSSA route, and ORTA_PROP
41
   * means that the NSSA route has propagate-bit set. These flags are used in
42
   * NSSA translation.
43
   */
44
#define ORTA_PREF 0x80000000
45
#define ORTA_NSSA 0x40000000
46
#define ORTA_PROP 0x20000000
47

    
48
  u32 metric1;
49
  u32 metric2;
50
  u32 tag;
51
  u32 rid;                        /* Router ID of real advertising router */
52
  struct ospf_area *oa;
53
  struct ospf_area *voa;        /* Used when route is replaced in ospf_rt_sum_tr(),
54
                                   NULL otherwise */
55
  struct mpnh *nhs;                /* Next hops computed during SPF */
56
  struct top_hash_entry *en;        /* LSA responsible for this orta */
57
}
58
orta;
59

    
60
typedef struct ort
61
{
62
  /*
63
   * Most OSPF routing table entries are for computed OSPF routes, these have
64
   * defined n.type. There are also few other cases: entries for configured area
65
   * networks (these have area_net field set) and entries for external routes
66
   * exported to OSPF (these have external_rte field set). These entries are
67
   * kept even if they do not contain 'proper' rt entry. That is needed to keep
68
   * allocated stable UID numbers (fn.uid), which are used as LSA IDs in OSPFv3
69
   * (see fibnode_to_lsaid()) for related LSAs (network summary LSAs in the
70
   * first case, external or NSSA LSAs in the second case). Entries for external
71
   * routes also have a second purpose - to prevent NSSA translation of received
72
   * NSSA routes if regular external routes were already originated for the same
73
   * network (see check_nssa_lsa()).
74
   *
75
   * old_* values are here to represent the last route update. old_rta is cached
76
   * (we keep reference), mainly for multipath nexthops.  old_rta == NULL means
77
   * route was not in the last update, in that case other old_* values are not
78
   * valid.
79
   */
80
  struct fib_node fn;
81
  orta n;
82
  u32 old_metric1, old_metric2, old_tag, old_rid;
83
  rta *old_rta;
84
  u8 external_rte;
85
  u8 area_net;
86
}
87
ort;
88

    
89
static inline int rt_is_nssa(ort *nf)
90
{ return nf->n.options & ORTA_NSSA; }
91

    
92

    
93
/*
94
 * Invariants for structs top_hash_entry (nodes of LSA db)
95
 * enforced by SPF calculation for final nodes (color == INSPF):
96
 * - only router, network and AS-external LSAs
97
 * - lsa.age < LSA_MAXAGE
98
 * - dist < LSINFINITY (or 2*LSINFINITY for ext-LSAs)
99
 * - nhs is non-NULL unless the node is oa->rt (calculating router itself)
100
 * - beware, nhs is not valid after SPF calculation
101
 *
102
 * Invariants for structs orta nodes of fib tables po->rtf, oa->rtr:
103
 * - nodes may be invalid (n.type == 0), in that case other invariants don't hold
104
 * - n.metric1 may be at most a small multiple of LSINFINITY,
105
 *   therefore sums do not overflow
106
 * - n.oa is always non-NULL
107
 * - n.nhs is always non-NULL unless it is configured stubnet
108
 * - n.en is non-NULL for external routes, NULL for intra/inter area routes.
109
 * - oa->rtr does not contain calculating router itself
110
 *
111
 * There are four types of nexthops in nhs fields:
112
 * - gateway nexthops (non-NULL iface, gw != IPA_NONE)
113
 * - device nexthops (non-NULL iface, gw == IPA_NONE)
114
 * - dummy vlink nexthops (NULL iface, gw == IPA_NONE)
115
 * - configured stubnets (nhs is NULL, only RTS_OSPF orta nodes in po->rtf)
116
 *
117
 * Dummy vlink nexthops and configured stubnets cannot be mixed with
118
 * regular ones, nhs field contains either list of gateway+device nodes,
119
 * one vlink node, or NULL for configured stubnet.
120
 *
121
 * Dummy vlink nexthops can appear in both network (rtf) and backbone area router
122
 * (rtr) tables for regular and inter-area routes, but only if areano > 1. They are
123
 * replaced in ospf_rt_sum_tr() and removed in ospf_rt_abr1(), therefore cannot
124
 * appear in ASBR pre-selection and external routes processing.
125
 */
126

    
127
void ospf_rt_spf(struct ospf_proto *p);
128
void ospf_rt_initort(struct fib_node *fn);
129

    
130

    
131
#endif /* _BIRD_OSPF_RT_H_ */