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, future_type;
  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   if (EMPTY_LIST(c->protos))
 118     cf_error("No protocol is specified in the config file");
 119 #ifdef IPV6
 120   if (!c->router_id)
 121     cf_error("Router ID must be configured manually on IPv6 routers");
 122 #endif
 123   return 1;
 124 }
 125
 126 /**
 127  * cli_parse - parse a CLI command
 128  * @c: temporary config structure
 129  *
 130  * cli_parse() is similar to config_parse(), but instead of a configuration,
 131  * it parses a CLI command. See the CLI module for more information.
 132  */
 133 int
 134 cli_parse(struct config *c)
 135 {
 136   new_config = c;
 137   c->sym_fallback = config->sym_hash;
 138   cfg_mem = c->mem;
 139   if (setjmp(conf_jmpbuf))
 140     return 0;
 141   cf_lex_init(1);
 142   cf_parse();
 143   return 1;
 144 }
 145
 146 /**
 147  * config_free - free a configuration
 148  * @c: configuration to be freed
 149  *
 150  * This function takes a &config structure and frees all resources
 151  * associated with it.
 152  */
 153 void
 154 config_free(struct config *c)
 155 {
 156   rfree(c->pool);
 157 }
 158
 159 void
 160 config_add_obstacle(struct config *c)
 161 {
 162   DBG("+++ adding obstacle %d\n", c->obstacle_count);
 163   c->obstacle_count++;
 164 }
 165
 166 void
 167 config_del_obstacle(struct config *c)
 168 {
 169   DBG("+++ deleting obstacle %d\n", c->obstacle_count);
 170   c->obstacle_count--;
 171   if (!c->obstacle_count)
 172     {
 173       ASSERT(config_event);
 174       ev_schedule(config_event);
 175     }
 176 }
 177
 178 static int
 179 global_commit(struct config *new, struct config *old)
 180 {
 181   if (!old)
 182     return 0;
 183
 184   if (!ipa_equal(old->listen_bgp_addr, new->listen_bgp_addr) ||
 185       (old->listen_bgp_port != new->listen_bgp_port) ||
 186       (old->listen_bgp_flags != new->listen_bgp_flags))
 187     log(L_WARN "Reconfiguration of BGP listening socket not implemented, please restart BIRD.");
 188
 189   if (!new->router_id)
 190     new->router_id = old->router_id;
 191   if (new->router_id != old->router_id)
 192     return 1;
 193   return 0;
 194 }
 195
 196 static int
 197 config_do_commit(struct config *c, int type)
 198 {
 199   int force_restart, nobs;
 200
 201   DBG("do_commit\n");
 202   old_config = config;
 203   config = new_config = c;
 204   if (old_config)
 205     old_config->obstacle_count++;
 206
 207   DBG("sysdep_commit\n");
 208   force_restart = sysdep_commit(c, old_config);
 209   DBG("global_commit\n");
 210   force_restart |= global_commit(c, old_config);
 211   DBG("rt_commit\n");
 212   rt_commit(c, old_config);
 213   DBG("protos_commit\n");
 214   protos_commit(c, old_config, force_restart, type);
 215   new_config = NULL;                    /* Just to be sure nobody uses that now */
 216   if (old_config)
 217     nobs = --old_config->obstacle_count;
 218   else
 219     nobs = 0;
 220   DBG("do_commit finished with %d obstacles remaining\n", nobs);
 221   return !nobs;
 222 }
 223
 224 static void
 225 config_done(void *unused UNUSED)
 226 {
 227   struct config *c;
 228
 229   DBG("config_done\n");
 230   for(;;)
 231     {
 232       if (config->shutdown)
 233         sysdep_shutdown_done();
 234       log(L_INFO "Reconfigured");
 235       if (old_config)
 236         {
 237           config_free(old_config);
 238           old_config = NULL;
 239         }
 240       if (!future_config)
 241         break;
 242       c = future_config;
 243       future_config = NULL;
 244       log(L_INFO "Reconfiguring to queued configuration");
 245       if (!config_do_commit(c, future_type))
 246         break;
 247     }
 248 }
 249
 250 /**
 251  * config_commit - commit a configuration
 252  * @c: new configuration
 253  * @type: type of reconfiguration (RECONFIG_SOFT or RECONFIG_HARD)
 254  *
 255  * When a configuration is parsed and prepared for use, the
 256  * config_commit() function starts the process of reconfiguration.
 257  * It checks whether there is already a reconfiguration in progress
 258  * in which case it just queues the new config for later processing.
 259  * Else it notifies all modules about the new configuration by calling
 260  * their commit() functions which can either accept it immediately
 261  * or call config_add_obstacle() to report that they need some time
 262  * to complete the reconfiguration. After all such obstacles are removed
 263  * using config_del_obstacle(), the old configuration is freed and
 264  * everything runs according to the new one.
 265  *
 266  * Result: %CONF_DONE if the configuration has been accepted immediately,
 267  * %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
 268  * if it's been queued due to another reconfiguration being in progress now
 269  * or %CONF_SHUTDOWN if BIRD is in shutdown mode and no new configurations
 270  * are accepted.
 271  */
 272 int
 273 config_commit(struct config *c, int type)
 274 {
 275   if (!config)                          /* First-time configuration */
 276     {
 277       config_do_commit(c, RECONFIG_HARD);
 278       return CONF_DONE;
 279     }
 280   if (old_config)                       /* Reconfiguration already in progress */
 281     {
 282       if (shutting_down == 2)
 283         {
 284           log(L_INFO "New configuration discarded due to shutdown");
 285           config_free(c);
 286           return CONF_SHUTDOWN;
 287         }
 288       if (future_config)
 289         {
 290           log(L_INFO "Queueing new configuration, ignoring the one already queued");
 291           config_free(future_config);
 292         }
 293       else
 294         log(L_INFO "Queued new configuration");
 295       future_config = c;
 296       future_type = type;
 297       return CONF_QUEUED;
 298     }
 299
 300   if (!shutting_down)
 301     log(L_INFO "Reconfiguring");
 302
 303   if (config_do_commit(c, type))
 304     {
 305       config_done(NULL);
 306       return CONF_DONE;
 307     }
 308   if (!config_event)
 309     {
 310       config_event = ev_new(&root_pool);
 311       config_event->hook = config_done;
 312     }
 313   return CONF_PROGRESS;
 314 }
 315
 316 /**
 317  * order_shutdown - order BIRD shutdown
 318  *
 319  * This function initiates shutdown of BIRD. It's accomplished by asking
 320  * for switching to an empty configuration.
 321  */
 322 void
 323 order_shutdown(void)
 324 {
 325   struct config *c;
 326
 327   if (shutting_down)
 328     return;
 329   log(L_INFO "Shutting down");
 330   c = lp_alloc(config->mem, sizeof(struct config));
 331   memcpy(c, config, sizeof(struct config));
 332   init_list(&c->protos);
 333   init_list(&c->tables);
 334   c->shutdown = 1;
 335   shutting_down = 1;
 336   config_commit(c, RECONFIG_HARD);
 337   shutting_down = 2;
 338 }
 339
 340 /**
 341  * cf_error - report a configuration error
 342  * @msg: printf-like format string
 343  *
 344  * cf_error() can be called during execution of config_parse(), that is
 345  * from the parser, a preconfig hook or a postconfig hook, to report an
 346  * error in the configuration.
 347  */
 348 void
 349 cf_error(char *msg, ...)
 350 {
 351   char buf[1024];
 352   va_list args;
 353
 354   va_start(args, msg);
 355   if (bvsnprintf(buf, sizeof(buf), msg, args) < 0)
 356     strcpy(buf, "<bug: error message too long>");
 357   new_config->err_msg = cfg_strdup(buf);
 358   new_config->err_lino = conf_lino;
 359   longjmp(conf_jmpbuf, 1);
 360 }
 361
 362 /**
 363  * cfg_strdup - copy a string to config memory
 364  * @c: string to copy
 365  *
 366  * cfg_strdup() creates a new copy of the string in the memory
 367  * pool associated with the configuration being currently parsed.
 368  * It's often used when a string literal occurs in the configuration
 369  * and we want to preserve it for further use.
 370  */
 371 char *
 372 cfg_strdup(char *c)
 373 {
 374   int l = strlen(c) + 1;
 375   char *z = cfg_allocu(l);
 376   memcpy(z, c, l);
 377   return z;
 378 }