conf/conf.c

   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;
  24  * if it's non-%NULL and the user wants to reconfigure once again, we just
  25  * free the previous queued config and replace it with the new one) and
  26  * finally a config being parsed (@new_config).
  27  *
  28  * Loading of new configuration is very simple: just call config_alloc()
  29  * to get a new &config structure, then use config_parse() to parse a
  30  * configuration file and fill all fields of the structure
  31  * and finally ask the config manager to switch to the new
  32  * config by calling config_commit().
  33  *
  34  * CLI commands are parsed in a very similar way -- there is also a stripped-down
  35  * &config structure associated with them and they are lex-ed and parsed by the
  36  * same functions, only a special fake token is prepended before the command
  37  * text to make the parser recognize only the rules corresponding to CLI commands.
  38  */
  39
  40 #include <setjmp.h>
  41 #include <stdarg.h>
  42
  43 #undef LOCAL_DEBUG
  44
  45 #include "nest/bird.h"
  46 #include "nest/route.h"
  47 #include "nest/protocol.h"
  48 #include "nest/iface.h"
  49 #include "lib/resource.h"
  50 #include "lib/string.h"
  51 #include "lib/event.h"
  52 #include "lib/timer.h"
  53 #include "conf/conf.h"
  54 #include "filter/filter.h"
  55
  56 static jmp_buf conf_jmpbuf;
  57
  58 struct config *config, *new_config, *old_config, *future_config;
  59 static event *config_event;
  60 int shutting_down;
  61 bird_clock_t boot_time;
  62
  63 /**
  64  * config_alloc - allocate a new configuration
  65  * @name: name of the config
  66  *
  67  * This function creates new &config structure, attaches a resource
  68  * pool and a linear memory pool to it and makes it available for
  69  * further use. Returns a pointer to the structure.
  70  */
  71 struct config *
  72 config_alloc(byte *name)
  73 {
  74   pool *p = rp_new(&root_pool, "Config");
  75   linpool *l = lp_new(p, 4080);
  76   struct config *c = lp_allocz(l, sizeof(struct config));
  77
  78   c->mrtdump_file = -1; /* Hack, this should be sysdep-specific */
  79   c->pool = p;
  80   cfg_mem = c->mem = l;
  81   c->file_name = cfg_strdup(name);
  82   c->load_time = now;
  83   c->tf_base.fmt1 = c->tf_log.fmt1 = "%d-%m-%Y %T";
  84
  85   if (!boot_time)
  86     boot_time = now;
  87   return c;
  88 }
  89
  90 /**
  91  * config_parse - parse a configuration
  92  * @c: configuration
  93  *
  94  * config_parse() reads input by calling a hook function pointed to
  95  * by @cf_read_hook and parses it according to the configuration
  96  * grammar. It also calls all the preconfig and postconfig hooks
  97  * before, resp. after parsing.
  98  *
  99  * Result: 1 if the config has been parsed successfully, 0 if any
 100  * error has occurred (such as anybody calling cf_error()) and
 101  * the @err_msg field has been set to the error message.
 102  */
 103 int
 104 config_parse(struct config *c)
 105 {
 106   DBG("Parsing configuration file `%s'\n", c->file_name);
 107   new_config = c;
 108   cfg_mem = c->mem;
 109   if (setjmp(conf_jmpbuf))
 110     return 0;
 111   cf_lex_init(0);
 112   sysdep_preconfig(c);
 113   protos_preconfig(c);
 114   rt_preconfig(c);
 115   cf_parse();
 116   protos_postconfig(c);
 117 #ifdef IPV6
 118   if (!c->router_id)
 119     cf_error("Router ID must be configured manually on IPv6 routers");
 120 #endif
 121   return 1;
 122 }
 123
 124 /**
 125  * cli_parse - parse a CLI command
 126  * @c: temporary config structure
 127  *
 128  * cli_parse() is similar to config_parse(), but instead of a configuration,
 129  * it parses a CLI command. See the CLI module for more information.
 130  */
 131 int
 132 cli_parse(struct config *c)
 133 {
 134   new_config = c;
 135   c->sym_fallback = config->sym_hash;
 136   cfg_mem = c->mem;
 137   if (setjmp(conf_jmpbuf))
 138     return 0;
 139   cf_lex_init(1);
 140   cf_parse();
 141   return 1;
 142 }
 143
 144 /**
 145  * config_free - free a configuration
 146  * @c: configuration to be freed
 147  *
 148  * This function takes a &config structure and frees all resources
 149  * associated with it.
 150  */
 151 void
 152 config_free(struct config *c)
 153 {
 154   rfree(c->pool);
 155 }
 156
 157 void
 158 config_add_obstacle(struct config *c)
 159 {
 160   DBG("+++ adding obstacle %d\n", c->obstacle_count);
 161   c->obstacle_count++;
 162 }
 163
 164 void
 165 config_del_obstacle(struct config *c)
 166 {
 167   DBG("+++ deleting obstacle %d\n", c->obstacle_count);
 168   c->obstacle_count--;
 169   if (!c->obstacle_count)
 170     {
 171       ASSERT(config_event);
 172       ev_schedule(config_event);
 173     }
 174 }
 175
 176 static int
 177 global_commit(struct config *new, struct config *old)
 178 {
 179   if (!old)
 180     return 0;
 181
 182   if (!ipa_equal(old->listen_bgp_addr, new->listen_bgp_addr) ||
 183       (old->listen_bgp_port != new->listen_bgp_port) ||
 184       (old->listen_bgp_flags != new->listen_bgp_flags))
 185     log(L_WARN "Reconfiguration of BGP listening socket not implemented, please restart BIRD.");
 186
 187   if (!new->router_id)
 188     new->router_id = old->router_id;
 189   if (new->router_id != old->router_id)
 190     return 1;
 191   return 0;
 192 }
 193
 194 static int
 195 config_do_commit(struct config *c, int type)
 196 {
 197   int force_restart, nobs;
 198
 199   DBG("do_commit\n");
 200   old_config = config;
 201   config = new_config = c;
 202   if (old_config)
 203     old_config->obstacle_count++;
 204   DBG("sysdep_commit\n");
 205   force_restart = sysdep_commit(c, old_config);
 206   DBG("global_commit\n");
 207   force_restart |= global_commit(c, old_config);
 208   DBG("rt_commit\n");
 209   rt_commit(c, old_config);
 210   DBG("protos_commit\n");
 211   protos_commit(c, old_config, force_restart, type);
 212   new_config = NULL;                    /* Just to be sure nobody uses that now */
 213   if (old_config)
 214     nobs = --old_config->obstacle_count;
 215   else
 216     nobs = 0;
 217   DBG("do_commit finished with %d obstacles remaining\n", nobs);
 218   return !nobs;
 219 }
 220
 221 static void
 222 config_done(void *unused UNUSED)
 223 {
 224   struct config *c;
 225
 226   DBG("config_done\n");
 227   for(;;)
 228     {
 229       if (config->shutdown)
 230         sysdep_shutdown_done();
 231       log(L_INFO "Reconfigured");
 232       if (old_config)
 233         {
 234           config_free(old_config);
 235           old_config = NULL;
 236         }
 237       if (!future_config)
 238         break;
 239       c = future_config;
 240       future_config = NULL;
 241       log(L_INFO "Switching to queued configuration...");
 242       if (!config_do_commit(c, RECONFIG_HARD))
 243         break;
 244     }
 245 }
 246
 247 /**
 248  * config_commit - commit a configuration
 249  * @c: new configuration
 250  * @type: type of reconfiguration (RECONFIG_SOFT or RECONFIG_HARD)
 251  *
 252  * When a configuration is parsed and prepared for use, the
 253  * config_commit() function starts the process of reconfiguration.
 254  * It checks whether there is already a reconfiguration in progress
 255  * in which case it just queues the new config for later processing.
 256  * Else it notifies all modules about the new configuration by calling
 257  * their commit() functions which can either accept it immediately
 258  * or call config_add_obstacle() to report that they need some time
 259  * to complete the reconfiguration. After all such obstacles are removed
 260  * using config_del_obstacle(), the old configuration is freed and
 261  * everything runs according to the new one.
 262  *
 263  * Result: %CONF_DONE if the configuration has been accepted immediately,
 264  * %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
 265  * if it's been queued due to another reconfiguration being in progress now
 266  * or %CONF_SHUTDOWN if BIRD is in shutdown mode and no new configurations
 267  * are accepted.
 268  */
 269 int
 270 config_commit(struct config *c, int type)
 271 {
 272   if (!config)                          /* First-time configuration */
 273     {
 274       config_do_commit(c, RECONFIG_HARD);
 275       return CONF_DONE;
 276     }
 277   if (old_config)                       /* Reconfiguration already in progress */
 278     {
 279       if (shutting_down == 2)
 280         {
 281           log(L_INFO "New configuration discarded due to shutdown");
 282           config_free(c);
 283           return CONF_SHUTDOWN;
 284         }
 285       if (future_config)
 286         {
 287           log(L_INFO "Queueing new configuration, ignoring the one already queued");
 288           config_free(future_config);
 289         }
 290       else
 291         log(L_INFO "Queued new configuration");
 292       future_config = c;
 293       return CONF_QUEUED;
 294     }
 295   if (config_do_commit(c, type))
 296     {
 297       config_done(NULL);
 298       return CONF_DONE;
 299     }
 300   if (!config_event)
 301     {
 302       config_event = ev_new(&root_pool);
 303       config_event->hook = config_done;
 304     }
 305   return CONF_PROGRESS;
 306 }
 307
 308 /**
 309  * order_shutdown - order BIRD shutdown
 310  *
 311  * This function initiates shutdown of BIRD. It's accomplished by asking
 312  * for switching to an empty configuration.
 313  */
 314 void
 315 order_shutdown(void)
 316 {
 317   struct config *c;
 318
 319   if (shutting_down)
 320     return;
 321   log(L_INFO "Shutting down");
 322   c = lp_alloc(config->mem, sizeof(struct config));
 323   memcpy(c, config, sizeof(struct config));
 324   init_list(&c->protos);
 325   init_list(&c->tables);
 326   c->shutdown = 1;
 327   shutting_down = 1;
 328   config_commit(c, RECONFIG_HARD);
 329   shutting_down = 2;
 330 }
 331
 332 /**
 333  * cf_error - report a configuration error
 334  * @msg: printf-like format string
 335  *
 336  * cf_error() can be called during execution of config_parse(), that is
 337  * from the parser, a preconfig hook or a postconfig hook, to report an
 338  * error in the configuration.
 339  */
 340 void
 341 cf_error(char *msg, ...)
 342 {
 343   char buf[1024];
 344   va_list args;
 345
 346   va_start(args, msg);
 347   if (bvsnprintf(buf, sizeof(buf), msg, args) < 0)
 348     strcpy(buf, "<bug: error message too long>");
 349   new_config->err_msg = cfg_strdup(buf);
 350   new_config->err_lino = conf_lino;
 351   longjmp(conf_jmpbuf, 1);
 352 }
 353
 354 /**
 355  * cfg_strdup - copy a string to config memory
 356  * @c: string to copy
 357  *
 358  * cfg_strdup() creates a new copy of the string in the memory
 359  * pool associated with the configuration being currently parsed.
 360  * It's often used when a string literal occurs in the configuration
 361  * and we want to preserve it for further use.
 362  */
 363 char *
 364 cfg_strdup(char *c)
 365 {
 366   int l = strlen(c) + 1;
 367   char *z = cfg_allocu(l);
 368   memcpy(z, c, l);
 369   return z;
 370 }