1/*
2 * IS-IS Rout(e)ing protocol - isis_csm.c
3 *                             IS-IS circuit state machine
4 * Copyright (C) 2001,2002    Sampo Saaristo
5 *                            Tampere University of Technology
6 *                            Institute of Communications Engineering
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public Licenseas published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16 * more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
21 */
22
23#include <zebra.h>
24
25#include "log.h"
26#include "memory.h"
27#include "if.h"
28#include "linklist.h"
29#include "command.h"
30#include "thread.h"
31#include "hash.h"
32#include "prefix.h"
33#include "stream.h"
34
35#include "isisd/dict.h"
36#include "isisd/include-netbsd/iso.h"
37#include "isisd/isis_constants.h"
38#include "isisd/isis_common.h"
39#include "isisd/isis_flags.h"
40#include "isisd/isis_circuit.h"
41#include "isisd/isis_tlv.h"
42#include "isisd/isis_lsp.h"
43#include "isisd/isis_pdu.h"
44#include "isisd/isis_network.h"
45#include "isisd/isis_misc.h"
46#include "isisd/isis_constants.h"
47#include "isisd/isis_adjacency.h"
48#include "isisd/isis_dr.h"
49#include "isisd/isisd.h"
50#include "isisd/isis_csm.h"
51#include "isisd/isis_events.h"
52
53extern struct isis *isis;
54
55static const char *csm_statestr[] = {
56  "C_STATE_NA",
57  "C_STATE_INIT",
58  "C_STATE_CONF",
59  "C_STATE_UP"
60};
61
62#define STATE2STR(S) csm_statestr[S]
63
64static const char *csm_eventstr[] = {
65  "NO_STATE",
66  "ISIS_ENABLE",
67  "IF_UP_FROM_Z",
68  "ISIS_DISABLE",
69  "IF_DOWN_FROM_Z",
70};
71
72#define EVENT2STR(E) csm_eventstr[E]
73
74struct isis_circuit *
75isis_csm_state_change (int event, struct isis_circuit *circuit, void *arg)
76{
77  int old_state;
78
79  old_state = circuit ? circuit->state : C_STATE_NA;
80  if (isis->debugs & DEBUG_EVENTS)
81    zlog_debug ("CSM_EVENT: %s", EVENT2STR (event));
82
83  switch (old_state)
84    {
85    case C_STATE_NA:
86      if (circuit)
87	zlog_warn ("Non-null circuit while state C_STATE_NA");
88      assert (circuit == NULL);
89      switch (event)
90	{
91	case ISIS_ENABLE:
92	  circuit = isis_circuit_new ();
93	  isis_circuit_configure (circuit, (struct isis_area *) arg);
94	  circuit->state = C_STATE_CONF;
95	  break;
96	case IF_UP_FROM_Z:
97	  circuit = isis_circuit_new ();
98	  isis_circuit_if_add (circuit, (struct interface *) arg);
99	  listnode_add (isis->init_circ_list, circuit);
100	  circuit->state = C_STATE_INIT;
101	  break;
102	case ISIS_DISABLE:
103	  zlog_warn ("circuit already disabled");
104	  break;
105	case IF_DOWN_FROM_Z:
106	  zlog_warn ("circuit already disconnected");
107	  break;
108	}
109      break;
110    case C_STATE_INIT:
111      assert (circuit);
112      switch (event)
113	{
114	case ISIS_ENABLE:
115	  isis_circuit_configure (circuit, (struct isis_area *) arg);
116	  if (isis_circuit_up (circuit) != ISIS_OK)
117	    {
118	      isis_circuit_deconfigure (circuit, (struct isis_area *) arg);
119	      break;
120	    }
121	  circuit->state = C_STATE_UP;
122	  isis_event_circuit_state_change (circuit, circuit->area, 1);
123	  listnode_delete (isis->init_circ_list, circuit);
124	  break;
125	case IF_UP_FROM_Z:
126          assert (circuit);
127	  zlog_warn ("circuit already connected");
128	  break;
129	case ISIS_DISABLE:
130	  zlog_warn ("circuit already disabled");
131	  break;
132	case IF_DOWN_FROM_Z:
133	  isis_circuit_if_del (circuit, (struct interface *) arg);
134	  listnode_delete (isis->init_circ_list, circuit);
135	  isis_circuit_del (circuit);
136	  circuit = NULL;
137	  break;
138	}
139      break;
140    case C_STATE_CONF:
141      assert (circuit);
142      switch (event)
143	{
144	case ISIS_ENABLE:
145	  zlog_warn ("circuit already enabled");
146	  break;
147	case IF_UP_FROM_Z:
148	  isis_circuit_if_add (circuit, (struct interface *) arg);
149	  if (isis_circuit_up (circuit) != ISIS_OK)
150            {
151              isis_circuit_if_del (circuit, (struct interface *) arg);
152	      break;
153            }
154	  circuit->state = C_STATE_UP;
155	  isis_event_circuit_state_change (circuit, circuit->area, 1);
156	  break;
157	case ISIS_DISABLE:
158	  isis_circuit_deconfigure (circuit, (struct isis_area *) arg);
159	  isis_circuit_del (circuit);
160	  circuit = NULL;
161	  break;
162	case IF_DOWN_FROM_Z:
163	  zlog_warn ("circuit already disconnected");
164	  break;
165	}
166      break;
167    case C_STATE_UP:
168      assert (circuit);
169      switch (event)
170	{
171	case ISIS_ENABLE:
172	  zlog_warn ("circuit already configured");
173	  break;
174	case IF_UP_FROM_Z:
175	  zlog_warn ("circuit already connected");
176	  break;
177	case ISIS_DISABLE:
178	  isis_circuit_down (circuit);
179	  isis_circuit_deconfigure (circuit, (struct isis_area *) arg);
180	  circuit->state = C_STATE_INIT;
181	  isis_event_circuit_state_change (circuit,
182                                           (struct isis_area *)arg, 0);
183	  listnode_add (isis->init_circ_list, circuit);
184	  break;
185	case IF_DOWN_FROM_Z:
186	  isis_circuit_down (circuit);
187          isis_circuit_if_del (circuit, (struct interface *) arg);
188	  circuit->state = C_STATE_CONF;
189	  isis_event_circuit_state_change (circuit, circuit->area, 0);
190	  break;
191	}
192      break;
193
194    default:
195      zlog_warn ("Invalid circuit state %d", old_state);
196    }
197
198  if (isis->debugs & DEBUG_EVENTS)
199    zlog_debug ("CSM_STATE_CHANGE: %s -> %s ", STATE2STR (old_state),
200		circuit ? STATE2STR (circuit->state) : STATE2STR (C_STATE_NA));
201
202  return circuit;
203}
204