bird/conf/conf.c
2016-01-20 16:46:58 +01:00

551 lines
15 KiB
C

/*
* BIRD Internet Routing Daemon -- Configuration File Handling
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Configuration manager
*
* Configuration of BIRD is complex, yet straightforward. There are three
* modules taking care of the configuration: config manager (which takes care
* of storage of the config information and controls switching between configs),
* lexical analyzer and parser.
*
* The configuration manager stores each config as a &config structure
* accompanied by a linear pool from which all information associated
* with the config and pointed to by the &config structure is allocated.
*
* There can exist up to four different configurations at one time: an active
* one (pointed to by @config), configuration we are just switching from
* (@old_config), one queued for the next reconfiguration (@future_config; if
* there is one and the user wants to reconfigure once again, we just free the
* previous queued config and replace it with the new one) and finally a config
* being parsed (@new_config). The stored @old_config is also used for undo
* reconfiguration, which works in a similar way. Reconfiguration could also
* have timeout (using @config_timer) and undo is automatically called if the
* new configuration is not confirmed later. The new config (@new_config) and
* associated linear pool (@cfg_mem) is non-NULL only during parsing.
*
* Loading of new configuration is very simple: just call config_alloc() to get
* a new &config structure, then use config_parse() to parse a configuration
* file and fill all fields of the structure and finally ask the config manager
* to switch to the new config by calling config_commit().
*
* CLI commands are parsed in a very similar way -- there is also a stripped-down
* &config structure associated with them and they are lex-ed and parsed by the
* same functions, only a special fake token is prepended before the command
* text to make the parser recognize only the rules corresponding to CLI commands.
*/
#include <setjmp.h>
#include <stdarg.h>
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/route.h"
#include "nest/protocol.h"
#include "nest/iface.h"
#include "lib/resource.h"
#include "lib/string.h"
#include "lib/event.h"
#include "lib/timer.h"
#include "conf/conf.h"
#include "filter/filter.h"
static jmp_buf conf_jmpbuf;
struct config *config, *new_config;
static struct config *old_config; /* Old configuration */
static struct config *future_config; /* New config held here if recon requested during recon */
static int old_cftype; /* Type of transition old_config -> config (RECONFIG_SOFT/HARD) */
static int future_cftype; /* Type of scheduled transition, may also be RECONFIG_UNDO */
/* Note that when future_cftype is RECONFIG_UNDO, then future_config is NULL,
therefore proper check for future scheduled config checks future_cftype */
static event *config_event; /* Event for finalizing reconfiguration */
static timer *config_timer; /* Timer for scheduled configuration rollback */
/* These are public just for cmd_show_status(), should not be accessed elsewhere */
int shutting_down; /* Shutdown requested, do not accept new config changes */
int configuring; /* Reconfiguration is running */
int undo_available; /* Undo was not requested from last reconfiguration */
/* Note that both shutting_down and undo_available are related to requests, not processing */
/**
* config_alloc - allocate a new configuration
* @name: name of the config
*
* This function creates new &config structure, attaches a resource
* pool and a linear memory pool to it and makes it available for
* further use. Returns a pointer to the structure.
*/
struct config *
config_alloc(byte *name)
{
pool *p = rp_new(&root_pool, "Config");
linpool *l = lp_new(p, 4080);
struct config *c = lp_allocz(l, sizeof(struct config));
/* Duplication of name string in local linear pool */
uint nlen = strlen(name) + 1;
char *ndup = lp_allocu(l, nlen);
memcpy(ndup, name, nlen);
c->mrtdump_file = -1; /* Hack, this should be sysdep-specific */
c->pool = p;
c->mem = l;
c->file_name = ndup;
c->load_time = now;
c->tf_route = c->tf_proto = (struct timeformat){"%T", "%F", 20*3600};
c->tf_base = c->tf_log = (struct timeformat){"%F %T", NULL, 0};
c->gr_wait = DEFAULT_GR_WAIT;
return c;
}
/**
* config_parse - parse a configuration
* @c: configuration
*
* config_parse() reads input by calling a hook function pointed to
* by @cf_read_hook and parses it according to the configuration
* grammar. It also calls all the preconfig and postconfig hooks
* before, resp. after parsing.
*
* Result: 1 if the config has been parsed successfully, 0 if any
* error has occurred (such as anybody calling cf_error()) and
* the @err_msg field has been set to the error message.
*/
int
config_parse(struct config *c)
{
int done = 0;
DBG("Parsing configuration file `%s'\n", c->file_name);
new_config = c;
cfg_mem = c->mem;
if (setjmp(conf_jmpbuf))
goto cleanup;
cf_lex_init(0, c);
sysdep_preconfig(c);
protos_preconfig(c);
rt_preconfig(c);
cf_parse();
protos_postconfig(c);
if (EMPTY_LIST(c->protos))
cf_error("No protocol is specified in the config file");
/* XXXX */
if (!c->router_id)
cf_error("Router ID must be configured manually");
done = 1;
cleanup:
new_config = NULL;
cfg_mem = NULL;
return done;
}
/**
* cli_parse - parse a CLI command
* @c: temporary config structure
*
* cli_parse() is similar to config_parse(), but instead of a configuration,
* it parses a CLI command. See the CLI module for more information.
*/
int
cli_parse(struct config *c)
{
int done = 0;
c->sym_fallback = config->sym_hash;
new_config = c;
cfg_mem = c->mem;
if (setjmp(conf_jmpbuf))
goto cleanup;
cf_lex_init(1, c);
cf_parse();
done = 1;
cleanup:
c->sym_fallback = NULL;
new_config = NULL;
cfg_mem = NULL;
return done;
}
/**
* config_free - free a configuration
* @c: configuration to be freed
*
* This function takes a &config structure and frees all resources
* associated with it.
*/
void
config_free(struct config *c)
{
if (c)
rfree(c->pool);
}
void
config_add_obstacle(struct config *c)
{
DBG("+++ adding obstacle %d\n", c->obstacle_count);
c->obstacle_count++;
}
void
config_del_obstacle(struct config *c)
{
DBG("+++ deleting obstacle %d\n", c->obstacle_count);
c->obstacle_count--;
if (!c->obstacle_count)
ev_schedule(config_event);
}
static int
global_commit(struct config *new, struct config *old)
{
if (!old)
return 0;
if (!ipa_equal(old->listen_bgp_addr, new->listen_bgp_addr) ||
(old->listen_bgp_port != new->listen_bgp_port) ||
(old->listen_bgp_flags != new->listen_bgp_flags))
log(L_WARN "Reconfiguration of BGP listening socket not implemented, please restart BIRD.");
if (!new->router_id)
{
new->router_id = old->router_id;
if (new->router_id_from)
{
u32 id = if_choose_router_id(new->router_id_from, old->router_id);
if (!id)
log(L_WARN "Cannot determine router ID, using old one");
else
new->router_id = id;
}
}
return 0;
}
static int
config_do_commit(struct config *c, int type)
{
if (type == RECONFIG_UNDO)
{
c = old_config;
type = old_cftype;
}
else
config_free(old_config);
old_config = config;
old_cftype = type;
config = c;
configuring = 1;
if (old_config && !config->shutdown)
log(L_INFO "Reconfiguring");
if (old_config)
old_config->obstacle_count++;
DBG("sysdep_commit\n");
int force_restart = sysdep_commit(c, old_config);
DBG("global_commit\n");
force_restart |= global_commit(c, old_config);
DBG("rt_commit\n");
rt_commit(c, old_config);
DBG("protos_commit\n");
protos_commit(c, old_config, force_restart, type);
int obs = 0;
if (old_config)
obs = --old_config->obstacle_count;
DBG("do_commit finished with %d obstacles remaining\n", obs);
return !obs;
}
static void
config_done(void *unused UNUSED)
{
if (config->shutdown)
sysdep_shutdown_done();
configuring = 0;
if (old_config)
log(L_INFO "Reconfigured");
if (future_cftype)
{
int type = future_cftype;
struct config *conf = future_config;
future_cftype = RECONFIG_NONE;
future_config = NULL;
log(L_INFO "Reconfiguring to queued configuration");
if (config_do_commit(conf, type))
config_done(NULL);
}
}
/**
* config_commit - commit a configuration
* @c: new configuration
* @type: type of reconfiguration (RECONFIG_SOFT or RECONFIG_HARD)
* @timeout: timeout for undo (or 0 for no timeout)
*
* When a configuration is parsed and prepared for use, the
* config_commit() function starts the process of reconfiguration.
* It checks whether there is already a reconfiguration in progress
* in which case it just queues the new config for later processing.
* Else it notifies all modules about the new configuration by calling
* their commit() functions which can either accept it immediately
* or call config_add_obstacle() to report that they need some time
* to complete the reconfiguration. After all such obstacles are removed
* using config_del_obstacle(), the old configuration is freed and
* everything runs according to the new one.
*
* When @timeout is nonzero, the undo timer is activated with given
* timeout. The timer is deactivated when config_commit(),
* config_confirm() or config_undo() is called.
*
* Result: %CONF_DONE if the configuration has been accepted immediately,
* %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
* if it's been queued due to another reconfiguration being in progress now
* or %CONF_SHUTDOWN if BIRD is in shutdown mode and no new configurations
* are accepted.
*/
int
config_commit(struct config *c, int type, int timeout)
{
if (shutting_down)
{
config_free(c);
return CONF_SHUTDOWN;
}
undo_available = 1;
if (timeout > 0)
tm_start(config_timer, timeout);
else
tm_stop(config_timer);
if (configuring)
{
if (future_cftype)
{
log(L_INFO "Queueing new configuration, ignoring the one already queued");
config_free(future_config);
}
else
log(L_INFO "Queueing new configuration");
future_cftype = type;
future_config = c;
return CONF_QUEUED;
}
if (config_do_commit(c, type))
{
config_done(NULL);
return CONF_DONE;
}
return CONF_PROGRESS;
}
/**
* config_confirm - confirm a commited configuration
*
* When the undo timer is activated by config_commit() with nonzero timeout,
* this function can be used to deactivate it and therefore confirm
* the current configuration.
*
* Result: %CONF_CONFIRM when the current configuration is confirmed,
* %CONF_NONE when there is nothing to confirm (i.e. undo timer is not active).
*/
int
config_confirm(void)
{
if (config_timer->expires == 0)
return CONF_NOTHING;
tm_stop(config_timer);
return CONF_CONFIRM;
}
/**
* config_undo - undo a configuration
*
* Function config_undo() can be used to change the current
* configuration back to stored %old_config. If no reconfiguration is
* running, this stored configuration is commited in the same way as a
* new configuration in config_commit(). If there is already a
* reconfiguration in progress and no next reconfiguration is
* scheduled, then the undo is scheduled for later processing as
* usual, but if another reconfiguration is already scheduled, then
* such reconfiguration is removed instead (i.e. undo is applied on
* the last commit that scheduled it).
*
* Result: %CONF_DONE if the configuration has been accepted immediately,
* %CONF_PROGRESS if it will take some time to switch to it, %CONF_QUEUED
* if it's been queued due to another reconfiguration being in progress now,
* %CONF_UNQUEUED if a scheduled reconfiguration is removed, %CONF_NOTHING
* if there is no relevant configuration to undo (the previous config request
* was config_undo() too) or %CONF_SHUTDOWN if BIRD is in shutdown mode and
* no new configuration changes are accepted.
*/
int
config_undo(void)
{
if (shutting_down)
return CONF_SHUTDOWN;
if (!undo_available || !old_config)
return CONF_NOTHING;
undo_available = 0;
tm_stop(config_timer);
if (configuring)
{
if (future_cftype)
{
config_free(future_config);
future_config = NULL;
log(L_INFO "Removing queued configuration");
future_cftype = RECONFIG_NONE;
return CONF_UNQUEUED;
}
else
{
log(L_INFO "Queueing undo configuration");
future_cftype = RECONFIG_UNDO;
return CONF_QUEUED;
}
}
if (config_do_commit(NULL, RECONFIG_UNDO))
{
config_done(NULL);
return CONF_DONE;
}
return CONF_PROGRESS;
}
extern void cmd_reconfig_undo_notify(void);
static void
config_timeout(struct timer *t)
{
log(L_INFO "Config timeout expired, starting undo");
cmd_reconfig_undo_notify();
int r = config_undo();
if (r < 0)
log(L_ERR "Undo request failed");
}
void
config_init(void)
{
config_event = ev_new(&root_pool);
config_event->hook = config_done;
config_timer = tm_new(&root_pool);
config_timer->hook = config_timeout;
}
/**
* order_shutdown - order BIRD shutdown
*
* This function initiates shutdown of BIRD. It's accomplished by asking
* for switching to an empty configuration.
*/
void
order_shutdown(void)
{
struct config *c;
if (shutting_down)
return;
log(L_INFO "Shutting down");
c = lp_alloc(config->mem, sizeof(struct config));
memcpy(c, config, sizeof(struct config));
init_list(&c->protos);
init_list(&c->tables);
c->shutdown = 1;
config_commit(c, RECONFIG_HARD, 0);
shutting_down = 1;
}
/**
* cf_error - report a configuration error
* @msg: printf-like format string
*
* cf_error() can be called during execution of config_parse(), that is
* from the parser, a preconfig hook or a postconfig hook, to report an
* error in the configuration.
*/
void
cf_error(char *msg, ...)
{
char buf[1024];
va_list args;
va_start(args, msg);
if (bvsnprintf(buf, sizeof(buf), msg, args) < 0)
strcpy(buf, "<bug: error message too long>");
new_config->err_msg = cfg_strdup(buf);
new_config->err_lino = ifs->lino;
new_config->err_file_name = ifs->file_name;
cf_lex_unwind();
longjmp(conf_jmpbuf, 1);
}
/**
* cfg_strdup - copy a string to config memory
* @c: string to copy
*
* cfg_strdup() creates a new copy of the string in the memory
* pool associated with the configuration being currently parsed.
* It's often used when a string literal occurs in the configuration
* and we want to preserve it for further use.
*/
char *
cfg_strdup(char *c)
{
int l = strlen(c) + 1;
char *z = cfg_allocu(l);
memcpy(z, c, l);
return z;
}
void
cfg_copy_list(list *dest, list *src, unsigned node_size)
{
node *dn, *sn;
init_list(dest);
WALK_LIST(sn, *src)
{
dn = cfg_alloc(node_size);
memcpy(dn, sn, node_size);
add_tail(dest, dn);
}
}