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