1/* BGP flap dampening
2   Copyright (C) 2001 IP Infusion Inc.
3
4This file is part of GNU Zebra.
5
6GNU Zebra is free software; you can redistribute it and/or modify it
7under the terms of the GNU General Public License as published by the
8Free Software Foundation; either version 2, or (at your option) any
9later version.
10
11GNU Zebra is distributed in the hope that it will be useful, but
12WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GNU Zebra; see the file COPYING.  If not, write to the Free
18Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
1902111-1307, USA.  */
20
21/* Structure maintained on a per-route basis. */
22struct bgp_damp_info
23{
24  /* Doubly linked list.  This information must be linked to
25     reuse_list or no_reuse_list.  */
26  struct bgp_damp_info *next;
27  struct bgp_damp_info *prev;
28
29  /* Figure-of-merit.  */
30  int penalty;
31
32  /* Number of flapping.  */
33  int flap;
34
35  /* First flap time  */
36  time_t start_time;
37
38  /* Last time penalty was updated.  */
39  time_t t_updated;
40
41  /* Time of route start to be suppressed.  */
42  time_t suppress_time;
43
44  /* Back reference to bgp_info. */
45  struct bgp_info *binfo;
46
47  /* Back reference to bgp_node. */
48  struct bgp_node *rn;
49
50  /* Current index in the reuse_list. */
51  int index;
52
53  /* Last time message type. */
54  u_char lastrecord;
55#define BGP_RECORD_UPDATE	1
56#define BGP_RECORD_WITHDRAW	2
57
58  afi_t afi;
59  safi_t safi;
60};
61
62/* Specified parameter set configuration. */
63struct bgp_damp_config
64{
65  /* Value over which routes suppressed.  */
66  int suppress_value;
67
68  /* Value below which suppressed routes reused.  */
69  int reuse_limit;
70
71  /* Max time a route can be suppressed.  */
72  int max_suppress_time;
73
74  /* Time during which accumulated penalty reduces by half.  */
75  int half_life;
76
77  /* Non-configurable parameters but fixed at implementation time.
78   * To change this values, init_bgp_damp() should be modified.
79   */
80  int tmax;		  /* Max time previous instability retained */
81  int reuse_list_size;		/* Number of reuse lists */
82  int reuse_index_size;		/* Size of reuse index array */
83
84  /* Non-configurable parameters.  Most of these are calculated from
85   * the configurable parameters above.
86   */
87  unsigned int ceiling;		/* Max value a penalty can attain */
88  int decay_rate_per_tick;	/* Calculated from half-life */
89  int decay_array_size;		/* Calculated using config parameters */
90  double scale_factor;
91  int reuse_scale_factor;
92
93  /* Decay array per-set based. */
94  double *decay_array;
95
96  /* Reuse index array per-set based. */
97  int *reuse_index;
98
99  /* Reuse list array per-set based. */
100  struct bgp_damp_info **reuse_list;
101  int reuse_offset;
102
103  /* All dampening information which is not on reuse list.  */
104  struct bgp_damp_info *no_reuse_list;
105
106  /* Reuse timer thread per-set base. */
107  struct thread* t_reuse;
108};
109
110#define BGP_DAMP_NONE           0
111#define BGP_DAMP_USED		1
112#define BGP_DAMP_SUPPRESSED	2
113
114/* Time granularity for reuse lists */
115#define DELTA_REUSE	          10
116
117/* Time granularity for decay arrays */
118#define DELTA_T 	           5
119
120#define DEFAULT_PENALTY         1000
121
122#define DEFAULT_HALF_LIFE         15
123#define DEFAULT_REUSE 	       	 750
124#define DEFAULT_SUPPRESS 	2000
125
126#define REUSE_LIST_SIZE          256
127#define REUSE_ARRAY_SIZE        1024
128
129int bgp_damp_enable (struct bgp *, afi_t, safi_t, int, int, int, int);
130int bgp_damp_disable (struct bgp *, afi_t, safi_t);
131int bgp_damp_withdraw (struct bgp_info *, struct bgp_node *,
132		       afi_t, safi_t, int);
133int bgp_damp_update (struct bgp_info *, struct bgp_node *, afi_t, safi_t);
134int bgp_damp_scan (struct bgp_info *, afi_t, safi_t);
135void bgp_damp_info_free (struct bgp_damp_info *, int);
136void bgp_damp_info_clean ();
137char * bgp_get_reuse_time (int, char*, size_t);
138int bgp_damp_decay (time_t, int);
139int bgp_config_write_damp (struct vty *);
140void bgp_damp_info_vty (struct vty *, struct bgp_info *);
141char * bgp_damp_reuse_time_vty (struct vty *, struct bgp_info *);
142