1: /*
2: * BIRD Internet Routing Daemon -- Configuration File Handling
3: *
4: * (c) 1998--2000 Martin Mares <mj@ucw.cz>
5: *
6: * Can be freely distributed and used under the terms of the GNU GPL.
7: */
8:
9: /**
10: * DOC: Configuration manager
11: *
12: * Configuration of BIRD is complex, yet straightforward. There are three
13: * modules taking care of the configuration: config manager (which takes care
14: * of storage of the config information and controls switching between configs),
15: * lexical analyzer and parser.
16: *
17: * The configuration manager stores each config as a &config structure
18: * accompanied by a linear pool from which all information associated
19: * with the config and pointed to by the &config structure is allocated.
20: *
21: * There can exist up to four different configurations at one time: an active
22: * one (pointed to by @config), configuration we are just switching from
23: * (@old_config), one queued for the next reconfiguration (@future_config; if
24: * there is one and the user wants to reconfigure once again, we just free the
25: * previous queued config and replace it with the new one) and finally a config
26: * being parsed (@new_config). The stored @old_config is also used for undo
27: * reconfiguration, which works in a similar way. Reconfiguration could also
28: * have timeout (using @config_timer) and undo is automatically called if the
29: * new configuration is not confirmed later. The new config (@new_config) and
30: * associated linear pool (@cfg_mem) is non-NULL only during parsing.
31: *
32: * Loading of new configuration is very simple: just call config_alloc() to get
33: * a new &config structure, then use config_parse() to parse a configuration
34: * file and fill all fields of the structure and finally ask the config manager
35: * to switch to the new config by calling config_commit().
36: *
37: * CLI commands are parsed in a very similar way -- there is also a stripped-down
38: * &config structure associated with them and they are lex-ed and parsed by the
39: * same functions, only a special fake token is prepended before the command
40: * text to make the parser recognize only the rules corresponding to CLI commands.
41: */
42:
43: #include <setjmp.h>
44: #include <stdarg.h>
45:
46: #undef LOCAL_DEBUG
47:
48: #include "nest/bird.h"
49: #include "nest/route.h"
50: #include "nest/protocol.h"
51: #include "nest/iface.h"
52: #include "lib/resource.h"
53: #include "lib/string.h"
54: #include "lib/event.h"
55: #include "lib/timer.h"
56: #include "conf/conf.h"
57: #include "filter/filter.h"
58:
59: static jmp_buf conf_jmpbuf;
60:
61: struct config *config, *new_config;
62:
63: static struct config *old_config; /* Old configuration */
64: static struct config *future_config; /* New config held here if recon requested during recon */
65: static int old_cftype; /* Type of transition old_config -> config (RECONFIG_SOFT/HARD) */
66: static int future_cftype; /* Type of scheduled transition, may also be RECONFIG_UNDO */
67: /* Note that when future_cftype is RECONFIG_UNDO, then future_config is NULL,
68: therefore proper check for future scheduled config checks future_cftype */
69:
70: static event *config_event; /* Event for finalizing reconfiguration */
71: static timer *config_timer; /* Timer for scheduled configuration rollback */
72:
73: /* These are public just for cmd_show_status(), should not be accessed elsewhere */
74: int shutting_down; /* Shutdown requested, do not accept new config changes */
75: int configuring; /* Reconfiguration is running */
76: int undo_available; /* Undo was not requested from last reconfiguration */
77: /* Note that both shutting_down and undo_available are related to requests, not processing */
78:
79: /**
80: * config_alloc - allocate a new configuration
81: * @name: name of the config
82: *
83: * This function creates new &config structure, attaches a resource
84: * pool and a linear memory pool to it and makes it available for
85: * further use. Returns a pointer to the structure.
86: */
87: struct config *
88: config_alloc(const byte *name)
89: {
90: pool *p = rp_new(&root_pool, "Config");
91: linpool *l = lp_new(p, 4080);
92: struct config *c = lp_allocz(l, sizeof(struct config));
93:
94: /* Duplication of name string in local linear pool */
95: uint nlen = strlen(name) + 1;
96: char *ndup = lp_allocu(l, nlen);
97: memcpy(ndup, name, nlen);
98:
99: c->mrtdump_file = -1; /* Hack, this should be sysdep-specific */
100: c->pool = p;
101: c->mem = l;
102: c->file_name = ndup;
103: c->load_time = now;
104: c->tf_route = c->tf_proto = (struct timeformat){"%T", "%F", 20*3600};
105: c->tf_base = c->tf_log = (struct timeformat){"%F %T", NULL, 0};
106: c->gr_wait = DEFAULT_GR_WAIT;
107:
108: return c;
109: }
110:
111: /**
112: * config_parse - parse a configuration
113: * @c: configuration
114: *
115: * config_parse() reads input by calling a hook function pointed to
116: * by @cf_read_hook and parses it according to the configuration
117: * grammar. It also calls all the preconfig and postconfig hooks
118: * before, resp. after parsing.
119: *
120: * Result: 1 if the config has been parsed successfully, 0 if any
121: * error has occurred (such as anybody calling cf_error()) and
122: * the @err_msg field has been set to the error message.
123: */
124: int
125: config_parse(struct config *c)
126: {
127: int done = 0;
128: DBG("Parsing configuration file `%s'\n", c->file_name);
129: new_config = c;
130: cfg_mem = c->mem;
131: if (setjmp(conf_jmpbuf))
132: goto cleanup;
133:
134: cf_lex_init(0, c);
135: sysdep_preconfig(c);
136: protos_preconfig(c);
137: rt_preconfig(c);
138: roa_preconfig(c);
139: cf_parse();
140: protos_postconfig(c);
141: if (EMPTY_LIST(c->protos))
142: cf_error("No protocol is specified in the config file");
143: #ifdef IPV6
144: if (!c->router_id)
145: cf_error("Router ID must be configured manually on IPv6 routers");
146: #endif
147: done = 1;
148:
149: cleanup:
150: new_config = NULL;
151: cfg_mem = NULL;
152: return done;
153: }
154:
155: /**
156: * cli_parse - parse a CLI command
157: * @c: temporary config structure
158: *
159: * cli_parse() is similar to config_parse(), but instead of a configuration,
160: * it parses a CLI command. See the CLI module for more information.
161: */
162: int
163: cli_parse(struct config *c)
164: {
165: int done = 0;
166: c->sym_fallback = config->sym_hash;
167: new_config = c;
168: cfg_mem = c->mem;
169: if (setjmp(conf_jmpbuf))
170: goto cleanup;
171:
172: cf_lex_init(1, c);
173: cf_parse();
174: done = 1;
175:
176: cleanup:
177: c->sym_fallback = NULL;
178: new_config = NULL;
179: cfg_mem = NULL;
180: return done;
181: }
182:
183: /**
184: * config_free - free a configuration
185: * @c: configuration to be freed
186: *
187: * This function takes a &config structure and frees all resources
188: * associated with it.
189: */
190: void
191: config_free(struct config *c)
192: {
193: if (c)
194: rfree(c->pool);
195: }
196:
197: void
198: config_add_obstacle(struct config *c)
199: {
200: DBG("+++ adding obstacle %d\n", c->obstacle_count);
201: c->obstacle_count++;
202: }
203:
204: void
205: config_del_obstacle(struct config *c)
206: {
207: DBG("+++ deleting obstacle %d\n", c->obstacle_count);
208: c->obstacle_count--;
209: if (!c->obstacle_count)
210: ev_schedule(config_event);
211: }
212:
213: static int
214: global_commit(struct config *new, struct config *old)
215: {
216: if (!old)
217: return 0;
218:
219: if (!ipa_equal(old->listen_bgp_addr, new->listen_bgp_addr) ||
220: (old->listen_bgp_port != new->listen_bgp_port) ||
221: (old->listen_bgp_flags != new->listen_bgp_flags))
222: log(L_WARN "Reconfiguration of BGP listening socket not implemented, please restart BIRD.");
223:
224: if (!new->router_id)
225: {
226: new->router_id = old->router_id;
227:
228: if (new->router_id_from)
229: {
230: u32 id = if_choose_router_id(new->router_id_from, old->router_id);
231: if (!id)
232: log(L_WARN "Cannot determine router ID, using old one");
233: else
234: new->router_id = id;
235: }
236: }
237:
238: return 0;
239: }
240:
241: static int
242: config_do_commit(struct config *c, int type)
243: {
244: if (type == RECONFIG_UNDO)
245: {
246: c = old_config;
247: type = old_cftype;
248: }
249: else
250: config_free(old_config);
251:
252: old_config = config;
253: old_cftype = type;
254: config = c;
255:
256: configuring = 1;
257: if (old_config && !config->shutdown)
258: log(L_INFO "Reconfiguring");
259:
260: if (old_config)
261: old_config->obstacle_count++;
262:
263: DBG("sysdep_commit\n");
264: int force_restart = sysdep_commit(c, old_config);
265: DBG("global_commit\n");
266: force_restart |= global_commit(c, old_config);
267: DBG("rt_commit\n");
268: rt_commit(c, old_config);
269: roa_commit(c, old_config);
270: DBG("protos_commit\n");
271: protos_commit(c, old_config, force_restart, type);
272:
273: int obs = 0;
274: if (old_config)
275: obs = --old_config->obstacle_count;
276:
277: DBG("do_commit finished with %d obstacles remaining\n", obs);
278: return !obs;
279: }
280:
281: static void
282: config_done(void *unused UNUSED)
283: {
284: if (config->shutdown)
285: sysdep_shutdown_done();
286:
287: configuring = 0;
288: if (old_config)
289: log(L_INFO "Reconfigured");
290:
291: if (future_cftype)
292: {
293: int type = future_cftype;
294: struct config *conf = future_config;
295: future_cftype = RECONFIG_NONE;
296: future_config = NULL;
297:
298: log(L_INFO "Reconfiguring to queued configuration");
299: if (config_do_commit(conf, type))
300: config_done(NULL);
301: }
302: }
303:
304: /**
305: * config_commit - commit a configuration
306: * @c: new configuration
307: * @type: type of reconfiguration (RECONFIG_SOFT or RECONFIG_HARD)
308: * @timeout: timeout for undo (or 0 for no timeout)
309: *
310: * When a configuration is parsed and prepared for use, the
311: * config_commit() function starts the process of reconfiguration.
312: * It checks whether there is already a reconfiguration in progress
313: * in which case it just queues the new config for later processing.
314: * Else it notifies all modules about the new configuration by calling
315: * their commit() functions which can either accept it immediately
316: * or call config_add_obstacle() to report that they need some time
317: * to complete the reconfiguration. After all such obstacles are removed
318: * using config_del_obstacle(), the old configuration is freed and
319: * everything runs according to the new one.
320: *
321: * When @timeout is nonzero, the undo timer is activated with given
322: * timeout. The timer is deactivated when config_commit(),
323: * config_confirm() or config_undo() is called.
324: *
325: * Result: %CONF_DONE if the configuration has been accepted immediately,
326: * %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
327: * if it's been queued due to another reconfiguration being in progress now
328: * or %CONF_SHUTDOWN if BIRD is in shutdown mode and no new configurations
329: * are accepted.
330: */
331: int
332: config_commit(struct config *c, int type, int timeout)
333: {
334: if (shutting_down)
335: {
336: config_free(c);
337: return CONF_SHUTDOWN;
338: }
339:
340: undo_available = 1;
341: if (timeout > 0)
342: tm_start(config_timer, timeout);
343: else
344: tm_stop(config_timer);
345:
346: if (configuring)
347: {
348: if (future_cftype)
349: {
350: log(L_INFO "Queueing new configuration, ignoring the one already queued");
351: config_free(future_config);
352: }
353: else
354: log(L_INFO "Queueing new configuration");
355:
356: future_cftype = type;
357: future_config = c;
358: return CONF_QUEUED;
359: }
360:
361: if (config_do_commit(c, type))
362: {
363: config_done(NULL);
364: return CONF_DONE;
365: }
366: return CONF_PROGRESS;
367: }
368:
369: /**
370: * config_confirm - confirm a commited configuration
371: *
372: * When the undo timer is activated by config_commit() with nonzero timeout,
373: * this function can be used to deactivate it and therefore confirm
374: * the current configuration.
375: *
376: * Result: %CONF_CONFIRM when the current configuration is confirmed,
377: * %CONF_NONE when there is nothing to confirm (i.e. undo timer is not active).
378: */
379: int
380: config_confirm(void)
381: {
382: if (config_timer->expires == 0)
383: return CONF_NOTHING;
384:
385: tm_stop(config_timer);
386:
387: return CONF_CONFIRM;
388: }
389:
390: /**
391: * config_undo - undo a configuration
392: *
393: * Function config_undo() can be used to change the current
394: * configuration back to stored %old_config. If no reconfiguration is
395: * running, this stored configuration is commited in the same way as a
396: * new configuration in config_commit(). If there is already a
397: * reconfiguration in progress and no next reconfiguration is
398: * scheduled, then the undo is scheduled for later processing as
399: * usual, but if another reconfiguration is already scheduled, then
400: * such reconfiguration is removed instead (i.e. undo is applied on
401: * the last commit that scheduled it).
402: *
403: * Result: %CONF_DONE if the configuration has been accepted immediately,
404: * %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
405: * if it's been queued due to another reconfiguration being in progress now,
406: * %CONF_UNQUEUED if a scheduled reconfiguration is removed, %CONF_NOTHING
407: * if there is no relevant configuration to undo (the previous config request
408: * was config_undo() too) or %CONF_SHUTDOWN if BIRD is in shutdown mode and
409: * no new configuration changes are accepted.
410: */
411: int
412: config_undo(void)
413: {
414: if (shutting_down)
415: return CONF_SHUTDOWN;
416:
417: if (!undo_available || !old_config)
418: return CONF_NOTHING;
419:
420: undo_available = 0;
421: tm_stop(config_timer);
422:
423: if (configuring)
424: {
425: if (future_cftype)
426: {
427: config_free(future_config);
428: future_config = NULL;
429:
430: log(L_INFO "Removing queued configuration");
431: future_cftype = RECONFIG_NONE;
432: return CONF_UNQUEUED;
433: }
434: else
435: {
436: log(L_INFO "Queueing undo configuration");
437: future_cftype = RECONFIG_UNDO;
438: return CONF_QUEUED;
439: }
440: }
441:
442: if (config_do_commit(NULL, RECONFIG_UNDO))
443: {
444: config_done(NULL);
445: return CONF_DONE;
446: }
447: return CONF_PROGRESS;
448: }
449:
450: extern void cmd_reconfig_undo_notify(void);
451:
452: static void
453: config_timeout(struct timer *t UNUSED)
454: {
455: log(L_INFO "Config timeout expired, starting undo");
456: cmd_reconfig_undo_notify();
457:
458: int r = config_undo();
459: if (r < 0)
460: log(L_ERR "Undo request failed");
461: }
462:
463: void
464: config_init(void)
465: {
466: config_event = ev_new(&root_pool);
467: config_event->hook = config_done;
468:
469: config_timer = tm_new(&root_pool);
470: config_timer->hook = config_timeout;
471: }
472:
473: /**
474: * order_shutdown - order BIRD shutdown
475: *
476: * This function initiates shutdown of BIRD. It's accomplished by asking
477: * for switching to an empty configuration.
478: */
479: void
480: order_shutdown(void)
481: {
482: struct config *c;
483:
484: if (shutting_down)
485: return;
486:
487: log(L_INFO "Shutting down");
488: c = lp_alloc(config->mem, sizeof(struct config));
489: memcpy(c, config, sizeof(struct config));
490: init_list(&c->protos);
491: init_list(&c->tables);
492: c->shutdown = 1;
493:
494: config_commit(c, RECONFIG_HARD, 0);
495: shutting_down = 1;
496: }
497:
498: /**
499: * cf_error - report a configuration error
500: * @msg: printf-like format string
501: *
502: * cf_error() can be called during execution of config_parse(), that is
503: * from the parser, a preconfig hook or a postconfig hook, to report an
504: * error in the configuration.
505: */
506: void
507: cf_error(char *msg, ...)
508: {
509: char buf[1024];
510: va_list args;
511:
512: va_start(args, msg);
513: if (bvsnprintf(buf, sizeof(buf), msg, args) < 0)
514: strcpy(buf, "<bug: error message too long>");
515: va_end(args);
516: new_config->err_msg = cfg_strdup(buf);
517: new_config->err_lino = ifs->lino;
518: new_config->err_file_name = ifs->file_name;
519: cf_lex_unwind();
520: longjmp(conf_jmpbuf, 1);
521: }
522:
523: /**
524: * cfg_strdup - copy a string to config memory
525: * @c: string to copy
526: *
527: * cfg_strdup() creates a new copy of the string in the memory
528: * pool associated with the configuration being currently parsed.
529: * It's often used when a string literal occurs in the configuration
530: * and we want to preserve it for further use.
531: */
532: char *
533: cfg_strdup(const char *c)
534: {
535: int l = strlen(c) + 1;
536: char *z = cfg_allocu(l);
537: memcpy(z, c, l);
538: return z;
539: }
540:
541:
542: void
543: cfg_copy_list(list *dest, list *src, unsigned node_size)
544: {
545: node *dn, *sn;
546:
547: init_list(dest);
548: WALK_LIST(sn, *src)
549: {
550: dn = cfg_alloc(node_size);
551: memcpy(dn, sn, node_size);
552: add_tail(dest, dn);
553: }
554: }
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