bird/nest/proto.c
Ondrej Zajicek d6a836f8d6 Fixes core state machine.
The core state machine was broken - it didn't free resources
in START -> DOWN transition and might freed resources after
UP -> STOP transition before protocol turned down. It leads
to deadlock on olock acquisition when lock was not freed
during previous stop.

The current behavior is that resources, allocated during
DOWN -> * transition, are freed in * -> DOWN transition,
and flushing (scheduled in UP -> *) just counteract
feeding (scheduled in * -> UP). Protocol fell down
when both flushing is done (if needed) and protocol
reports DOWN.

BTW, is thera a reason why neighbour cache item acquired
by protocol is not tracked by resource mechanism?
2008-12-08 12:24:55 +01:00

817 lines
20 KiB
C

/*
* BIRD -- Protocols
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/protocol.h"
#include "lib/resource.h"
#include "lib/lists.h"
#include "lib/event.h"
#include "lib/string.h"
#include "conf/conf.h"
#include "nest/route.h"
#include "nest/iface.h"
#include "nest/cli.h"
#include "filter/filter.h"
static pool *proto_pool;
static list protocol_list;
static list proto_list;
#define WALK_PROTO_LIST(p) do { \
node *nn; \
WALK_LIST(nn, proto_list) { \
struct proto *p = SKIP_BACK(struct proto, glob_node, nn);
#define WALK_PROTO_LIST_END } } while(0)
#define PD(pr, msg, args...) do { if (pr->debug & D_STATES) { log(L_TRACE "%s: " msg, pr->name , ## args); } } while(0)
list active_proto_list;
static list inactive_proto_list;
static list initial_proto_list;
static list flush_proto_list;
static event *proto_flush_event;
static char *p_states[] = { "DOWN", "START", "UP", "STOP" };
static char *c_states[] = { "HUNGRY", "FEEDING", "HAPPY", "FLUSHING" };
static void proto_flush_all(void *);
static void proto_rethink_goal(struct proto *p);
static char *proto_state_name(struct proto *p);
static void
proto_enqueue(list *l, struct proto *p)
{
add_tail(l, &p->n);
p->last_state_change = now;
}
static void
proto_relink(struct proto *p)
{
list *l;
if (p->debug & D_STATES)
{
char *name = proto_state_name(p);
if (name != p->last_state_name_announced)
{
p->last_state_name_announced = name;
PD(p, "State changed to %s", proto_state_name(p));
}
}
else
p->last_state_name_announced = NULL;
rem_node(&p->n);
switch (p->core_state)
{
case FS_HAPPY:
l = &active_proto_list;
break;
case FS_FLUSHING:
l = &flush_proto_list;
break;
default:
l = &inactive_proto_list;
}
proto_enqueue(l, p);
}
/**
* proto_new - create a new protocol instance
* @c: protocol configuration
* @size: size of protocol data structure (each protocol instance is represented by
* a structure starting with generic part [struct &proto] and continued
* with data specific to the protocol)
*
* When a new configuration has been read in, the core code starts
* initializing all the protocol instances configured by calling their
* init() hooks with the corresponding instance configuration. The initialization
* code of the protocol is expected to create a new instance according to the
* configuration by calling this function and then modifying the default settings
* to values wanted by the protocol.
*/
void *
proto_new(struct proto_config *c, unsigned size)
{
struct protocol *pr = c->protocol;
struct proto *p = mb_allocz(proto_pool, size);
p->cf = c;
p->debug = c->debug;
p->name = c->name;
p->preference = c->preference;
p->disabled = c->disabled;
p->proto = pr;
p->table = c->table->table;
p->in_filter = c->in_filter;
p->out_filter = c->out_filter;
p->min_scope = SCOPE_SITE;
p->hash_key = random_u32();
c->proto = p;
return p;
}
static void
proto_init_instance(struct proto *p)
{
/* Here we cannot use p->cf->name since it won't survive reconfiguration */
p->pool = rp_new(proto_pool, p->proto->name);
p->attn = ev_new(p->pool);
p->attn->data = p;
rt_lock_table(p->table);
}
/**
* proto_add_announce_hook - connect protocol to a routing table
* @p: protocol instance
* @t: routing table to connect to
*
* This function creates a connection between the protocol instance @p
* and the routing table @t, making the protocol hear all changes in
* the table.
*
* Unless you want to listen to multiple routing tables (as the Pipe
* protocol does), you needn't to worry about this function since the
* connection to the protocol's primary routing table is initialized
* automatically by the core code.
*/
struct announce_hook *
proto_add_announce_hook(struct proto *p, struct rtable *t)
{
struct announce_hook *h;
if (!p->rt_notify)
return NULL;
DBG("Connecting protocol %s to table %s\n", p->name, t->name);
PD(p, "Connected to table %s", t->name);
h = mb_alloc(p->pool, sizeof(struct announce_hook));
h->table = t;
h->proto = p;
h->next = p->ahooks;
p->ahooks = h;
add_tail(&t->hooks, &h->n);
return h;
}
static void
proto_flush_hooks(struct proto *p)
{
struct announce_hook *h;
for(h=p->ahooks; h; h=h->next)
rem_node(&h->n);
p->ahooks = NULL;
}
/**
* proto_config_new - create a new protocol configuration
* @pr: protocol the configuration will belong to
* @size: size of the structure including generic data
*
* Whenever the configuration file says that a new instance
* of a routing protocol should be created, the parser calls
* proto_config_new() to create a configuration entry for this
* instance (a structure staring with the &proto_config header
* containing all the generic items followed by protocol-specific
* ones). Also, the configuration entry gets added to the list
* of protocol instances kept in the configuration.
*/
void *
proto_config_new(struct protocol *pr, unsigned size)
{
struct proto_config *c = cfg_allocz(size);
add_tail(&new_config->protos, &c->n);
c->global = new_config;
c->protocol = pr;
c->name = pr->name;
c->out_filter = FILTER_REJECT;
c->table = c->global->master_rtc;
c->debug = new_config->proto_default_debug;
return c;
}
/**
* protos_preconfig - pre-configuration processing
* @c: new configuration
*
* This function calls the preconfig() hooks of all routing
* protocols available to prepare them for reading of the new
* configuration.
*/
void
protos_preconfig(struct config *c)
{
struct protocol *p;
init_list(&c->protos);
DBG("Protocol preconfig:");
WALK_LIST(p, protocol_list)
{
DBG(" %s", p->name);
p->name_counter = 0;
if (p->preconfig)
p->preconfig(p, c);
}
DBG("\n");
}
/**
* protos_postconfig - post-configuration processing
* @c: new configuration
*
* This function calls the postconfig() hooks of all protocol
* instances specified in configuration @c.
*/
void
protos_postconfig(struct config *c)
{
struct proto_config *x;
struct protocol *p;
DBG("Protocol postconfig:");
WALK_LIST(x, c->protos)
{
DBG(" %s", x->name);
p = x->protocol;
if (p->postconfig)
p->postconfig(x);
}
DBG("\n");
}
static struct proto *
proto_init(struct proto_config *c)
{
struct protocol *p = c->protocol;
struct proto *q = p->init(c);
q->proto_state = PS_DOWN;
q->core_state = FS_HUNGRY;
proto_enqueue(&initial_proto_list, q);
add_tail(&proto_list, &q->glob_node);
PD(q, "Initializing%s", q->disabled ? " [disabled]" : "");
return q;
}
/**
* protos_commit - commit new protocol configuration
* @new: new configuration
* @old: old configuration or %NULL if it's boot time config
* @force_reconfig: force restart of all protocols (used for example
* when the router ID changes)
*
* Scan differences between @old and @new configuration and adjust all
* protocol instances to conform to the new configuration.
*
* When a protocol exists in the new configuration, but it doesn't in the
* original one, it's immediately started. When a collision with the other
* running protocol would arise, the new protocol will be temporarily stopped
* by the locking mechanism.
*
* When a protocol exists in the old configuration, but it doesn't in the
* new one, it's shut down and deleted after the shutdown completes.
*
* When a protocol exists in both configurations, the core decides whether
* it's possible to reconfigure it dynamically (it checks all the core properties
* of the protocol and if they match, it asks the reconfigure() hook of the
* protocol to see if the protocol is able to switch to the new configuration).
* If it isn't possible, the protocol is shut down and a new instance is started
* with the new configuration after the shutdown is completed.
*/
void
protos_commit(struct config *new, struct config *old, int force_reconfig)
{
struct proto_config *oc, *nc;
struct proto *p, *n;
DBG("protos_commit:\n");
if (old)
{
WALK_LIST(oc, old->protos)
{
struct proto *p = oc->proto;
struct symbol *sym = cf_find_symbol(oc->name);
if (sym && sym->class == SYM_PROTO && !new->shutdown)
{
/* Found match, let's check if we can smoothly switch to new configuration */
nc = sym->def;
if (!force_reconfig
&& nc->protocol == oc->protocol
&& nc->preference == oc->preference
&& nc->disabled == oc->disabled
&& nc->table->table == oc->table->table
&& filter_same(nc->in_filter, oc->in_filter)
&& filter_same(nc->out_filter, oc->out_filter)
&& p->proto_state != PS_DOWN)
{
/* Generic attributes match, try converting them and then ask the protocol */
p->debug = nc->debug;
if (p->proto->reconfigure && p->proto->reconfigure(p, nc))
{
DBG("\t%s: same\n", oc->name);
PD(p, "Reconfigured");
p->cf = nc;
p->name = nc->name;
p->in_filter = nc->in_filter;
p->out_filter = nc->out_filter;
nc->proto = p;
continue;
}
}
/* Unsuccessful, force reconfig */
DBG("\t%s: power cycling\n", oc->name);
PD(p, "Reconfiguration failed, restarting");
p->cf_new = nc;
nc->proto = p;
}
else
{
DBG("\t%s: deleting\n", oc->name);
PD(p, "Unconfigured");
p->cf_new = NULL;
}
p->reconfiguring = 1;
config_add_obstacle(old);
proto_rethink_goal(p);
}
}
WALK_LIST(nc, new->protos)
if (!nc->proto)
{
DBG("\t%s: adding\n", nc->name);
proto_init(nc);
}
DBG("\tdone\n");
DBG("Protocol start\n");
WALK_LIST_DELSAFE(p, n, initial_proto_list)
proto_rethink_goal(p);
}
static void
proto_rethink_goal(struct proto *p)
{
struct protocol *q;
if (p->reconfiguring && p->core_state == FS_HUNGRY && p->proto_state == PS_DOWN)
{
struct proto_config *nc = p->cf_new;
DBG("%s has shut down for reconfiguration\n", p->name);
config_del_obstacle(p->cf->global);
rem_node(&p->n);
rem_node(&p->glob_node);
mb_free(p);
if (!nc)
return;
p = proto_init(nc);
}
/* Determine what state we want to reach */
if (p->disabled || p->reconfiguring)
{
p->core_goal = FS_HUNGRY;
if (p->core_state == FS_HUNGRY && p->proto_state == PS_DOWN)
return;
}
else
{
p->core_goal = FS_HAPPY;
if (p->core_state == FS_HAPPY && p->proto_state == PS_UP)
return;
}
q = p->proto;
if (p->core_goal == FS_HAPPY) /* Going up */
{
if (p->core_state == FS_HUNGRY && p->proto_state == PS_DOWN)
{
DBG("Kicking %s up\n", p->name);
PD(p, "Starting");
proto_init_instance(p);
proto_notify_state(p, (q->start ? q->start(p) : PS_UP));
}
}
else /* Going down */
{
if (p->proto_state == PS_START || p->proto_state == PS_UP)
{
DBG("Kicking %s down\n", p->name);
PD(p, "Shutting down");
proto_notify_state(p, (q->shutdown ? q->shutdown(p) : PS_DOWN));
}
}
}
/**
* protos_dump_all - dump status of all protocols
*
* This function dumps status of all existing protocol instances to the
* debug output. It involves printing of general status information
* such as protocol states, its position on the protocol lists
* and also calling of a dump() hook of the protocol to print
* the internals.
*/
void
protos_dump_all(void)
{
struct proto *p;
debug("Protocols:\n");
WALK_LIST(p, active_proto_list)
{
debug(" protocol %s state %s/%s\n", p->name,
p_states[p->proto_state], c_states[p->core_state]);
if (p->in_filter)
debug("\tInput filter: %s\n", filter_name(p->in_filter));
if (p->out_filter != FILTER_REJECT)
debug("\tOutput filter: %s\n", filter_name(p->out_filter));
if (p->disabled)
debug("\tDISABLED\n");
else if (p->proto->dump)
p->proto->dump(p);
}
WALK_LIST(p, inactive_proto_list)
debug(" inactive %s: state %s/%s\n", p->name, p_states[p->proto_state], c_states[p->core_state]);
WALK_LIST(p, initial_proto_list)
debug(" initial %s\n", p->name);
WALK_LIST(p, flush_proto_list)
debug(" flushing %s\n", p->name);
}
/**
* proto_build - make a single protocol available
* @p: the protocol
*
* After the platform specific initialization code uses protos_build()
* to add all the standard protocols, it should call proto_build() for
* all platform specific protocols to inform the core that they exist.
*/
void
proto_build(struct protocol *p)
{
add_tail(&protocol_list, &p->n);
if (p->attr_class)
{
ASSERT(!attr_class_to_protocol[p->attr_class]);
attr_class_to_protocol[p->attr_class] = p;
}
}
/**
* protos_build - build a protocol list
*
* This function is called during BIRD startup to insert
* all standard protocols to the global protocol list. Insertion
* of platform specific protocols (such as the kernel syncer)
* is in the domain of competence of the platform dependent
* startup code.
*/
void
protos_build(void)
{
init_list(&protocol_list);
init_list(&proto_list);
init_list(&active_proto_list);
init_list(&inactive_proto_list);
init_list(&initial_proto_list);
init_list(&flush_proto_list);
proto_build(&proto_device);
#ifdef CONFIG_RIP
proto_build(&proto_rip);
#endif
#ifdef CONFIG_STATIC
proto_build(&proto_static);
#endif
#ifdef CONFIG_OSPF
proto_build(&proto_ospf);
#endif
#ifdef CONFIG_PIPE
proto_build(&proto_pipe);
#endif
#ifdef CONFIG_BGP
proto_build(&proto_bgp);
#endif
proto_pool = rp_new(&root_pool, "Protocols");
proto_flush_event = ev_new(proto_pool);
proto_flush_event->hook = proto_flush_all;
}
static void
proto_fell_down(struct proto *p)
{
DBG("Protocol %s down\n", p->name);
rt_unlock_table(p->table);
proto_rethink_goal(p);
}
static void
proto_feed_more(void *P)
{
struct proto *p = P;
if (p->core_state != FS_FEEDING)
return;
DBG("Feeding protocol %s continued\n", p->name);
if (rt_feed_baby(p))
{
p->core_state = FS_HAPPY;
proto_relink(p);
DBG("Protocol %s up and running\n", p->name);
}
else
{
p->attn->hook = proto_feed_more;
ev_schedule(p->attn); /* Will continue later... */
}
}
static void
proto_feed(void *P)
{
struct proto *p = P;
if (p->core_state != FS_FEEDING)
return;
DBG("Feeding protocol %s\n", p->name);
proto_add_announce_hook(p, p->table);
if_feed_baby(p);
proto_feed_more(P);
}
static void
proto_schedule_flush(struct proto *p)
{
/* Need to abort feeding */
if (p->core_state == FS_FEEDING)
rt_feed_baby_abort(p);
DBG("%s: Scheduling flush\n", p->name);
p->core_state = FS_FLUSHING;
proto_relink(p);
proto_flush_hooks(p);
ev_schedule(proto_flush_event);
}
static void
proto_schedule_feed(struct proto *p)
{
DBG("%s: Scheduling meal\n", p->name);
p->core_state = FS_FEEDING;
proto_relink(p);
p->attn->hook = proto_feed;
ev_schedule(p->attn);
}
/**
* proto_notify_state - notify core about protocol state change
* @p: protocol the state of which has changed
* @ps: the new status
*
* Whenever a state of a protocol changes due to some event internal
* to the protocol (i.e., not inside a start() or shutdown() hook),
* it should immediately notify the core about the change by calling
* proto_notify_state() which will write the new state to the &proto
* structure and take all the actions necessary to adapt to the new
* state. State change to PS_DOWN immediately frees resources of protocol
* and might execute start callback of protocol; therefore,
* it should be used at tail positions of protocol callbacks.
*/
void
proto_notify_state(struct proto *p, unsigned ps)
{
unsigned ops = p->proto_state;
unsigned cs = p->core_state;
DBG("%s reporting state transition %s/%s -> */%s\n", p->name, c_states[cs], p_states[ops], p_states[ps]);
if (ops == ps)
return;
p->proto_state = ps;
switch (ps)
{
case PS_DOWN:
neigh_prune(); // FIXME convert neighbors to resource?
rfree(p->pool);
p->pool = NULL;
if (cs == FS_HUNGRY) /* Shutdown finished */
{
proto_fell_down(p);
return; /* The protocol might have ceased to exist */
}
/* Otherwise, we have something to flush... */
else if (cs != FS_FLUSHING)
proto_schedule_flush(p);
break;
case PS_START:
ASSERT(ops == PS_DOWN);
ASSERT(cs == FS_HUNGRY);
break;
case PS_UP:
ASSERT(ops == PS_DOWN || ops == PS_START);
ASSERT(cs == FS_HUNGRY);
proto_schedule_feed(p);
break;
case PS_STOP:
if ((cs = FS_FEEDING) || (cs == FS_HAPPY))
proto_schedule_flush(p);
break;
default:
bug("Invalid state transition for %s from %s/%s to */%s", p->name, c_states[cs], p_states[ops], p_states[ps]);
}
}
static void
proto_flush_all(void *unused UNUSED)
{
struct proto *p;
rt_prune_all();
while ((p = HEAD(flush_proto_list))->n.next)
{
DBG("Flushing protocol %s\n", p->name);
p->core_state = FS_HUNGRY;
proto_relink(p);
if (p->proto_state == PS_DOWN)
proto_fell_down(p);
}
}
/*
* CLI Commands
*/
static char *
proto_state_name(struct proto *p)
{
#define P(x,y) ((x << 4) | y)
switch (P(p->proto_state, p->core_state))
{
case P(PS_DOWN, FS_HUNGRY): return "down";
case P(PS_START, FS_HUNGRY): return "start";
case P(PS_UP, FS_HUNGRY):
case P(PS_UP, FS_FEEDING): return "feed";
case P(PS_STOP, FS_HUNGRY): return "stop";
case P(PS_UP, FS_HAPPY): return "up";
case P(PS_STOP, FS_FLUSHING):
case P(PS_DOWN, FS_FLUSHING): return "flush";
default: return "???";
}
#undef P
}
static void
proto_do_show(struct proto *p, int verbose)
{
byte buf[256], reltime[TM_RELTIME_BUFFER_SIZE];
buf[0] = 0;
if (p->proto->get_status)
p->proto->get_status(p, buf);
tm_format_reltime(reltime, p->last_state_change);
cli_msg(-1002, "%-8s %-8s %-8s %-5s %-5s %s",
p->name,
p->proto->name,
p->table->name,
proto_state_name(p),
reltime,
buf);
if (verbose)
{
cli_msg(-1006, "\tPreference: %d", p->preference);
cli_msg(-1006, "\tInput filter: %s", filter_name(p->in_filter));
cli_msg(-1006, "\tOutput filter: %s", filter_name(p->out_filter));
}
}
void
proto_show(struct symbol *s, int verbose)
{
if (s && s->class != SYM_PROTO)
{
cli_msg(9002, "%s is not a protocol", s->name);
return;
}
cli_msg(-2002, "name proto table state since info");
if (s)
proto_do_show(((struct proto_config *)s->def)->proto, verbose);
else
{
WALK_PROTO_LIST(p)
proto_do_show(p, verbose);
WALK_PROTO_LIST_END;
}
cli_msg(0, "");
}
struct proto *
proto_get_named(struct symbol *sym, struct protocol *pr)
{
struct proto *p, *q;
if (sym)
{
if (sym->class != SYM_PROTO)
cf_error("%s: Not a protocol", sym->name);
p = ((struct proto_config *)sym->def)->proto;
if (!p || p->proto != pr)
cf_error("%s: Not a %s protocol", sym->name, pr->name);
}
else
{
p = NULL;
WALK_LIST(q, active_proto_list)
if (q->proto == pr)
{
if (p)
cf_error("There are multiple %s protocols running", pr->name);
p = q;
}
if (!p)
cf_error("There is no %s protocol running", pr->name);
}
return p;
}
void
proto_xxable(char *pattern, int xx)
{
int cnt = 0;
WALK_PROTO_LIST(p)
if (patmatch(pattern, p->name))
{
cnt++;
switch (xx)
{
case 0:
if (p->disabled)
cli_msg(-8, "%s: already disabled", p->name);
else
{
cli_msg(-9, "%s: disabled", p->name);
p->disabled = 1;
}
break;
case 1:
if (!p->disabled)
cli_msg(-10, "%s: already enabled", p->name);
else
{
cli_msg(-11, "%s: enabled", p->name);
p->disabled = 0;
}
break;
case 2:
if (p->disabled)
cli_msg(-8, "%s: already disabled", p->name);
else
{
p->disabled = 1;
proto_rethink_goal(p);
p->disabled = 0;
cli_msg(-12, "%s: restarted", p->name);
}
break;
default:
ASSERT(0);
}
proto_rethink_goal(p);
}
WALK_PROTO_LIST_END;
if (!cnt)
cli_msg(8003, "No protocols match");
else
cli_msg(0, "");
}
void
proto_debug(char *pattern, unsigned int mask)
{
int cnt = 0;
WALK_PROTO_LIST(p)
if (patmatch(pattern, p->name))
{
cnt++;
p->debug = mask;
}
WALK_PROTO_LIST_END;
if (!cnt)
cli_msg(8003, "No protocols match");
else
cli_msg(0, "");
}