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chan_sip.c: Fix registration timeout and expire deadlock potential.

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This patch is part of a series to resolve deadlocks in chan_sip.c.

Stopping a scheduled event can result in a deadlock if the scheduled event
is running when you try to stop the event.  If you hold a lock needed by
the scheduled event while trying to stop the scheduled event then a
deadlock can happen.  The general strategy for resolving the deadlock
potential is to push the actual starting and stopping of the scheduled
events off onto the scheduler/do_monitor() thread by scheduling an
immediate one shot scheduled event.  Some restructuring may be needed
because the code may assume that the start/stop of the scheduled events is
immediate.

ASTERISK-25023

Change-Id: I2e40de89efc8ae6e8850771d089ca44bc604b508
This commit is contained in:
Richard Mudgett
2016-03-10 17:01:12 -06:00
parent 32bd7a64f9
commit 5f6627a8a4
2 changed files with 185 additions and 63 deletions
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245
channels/chan_sip.c
View File

@@ -1372,7 +1372,6 @@ static void ast_sip_ouraddrfor(const struct ast_sockaddr *them, struct ast_socka
static void sip_registry_destroy(void *reg);
static int sip_register(const char *value, int lineno);
static const char *regstate2str(enum sipregistrystate regstate) attribute_const;
static int sip_reregister(const void *data);
static int __sip_do_register(struct sip_registry *r);
static int sip_reg_timeout(const void *data);
static void sip_send_all_registers(void);
@@ -6504,8 +6503,6 @@ static void sip_registry_destroy(void *obj)
reg->call = dialog_unref(reg->call, "unref reg->call");
/* reg->call = sip_destroy(reg->call); */
}
AST_SCHED_DEL(sched, reg->expire);
AST_SCHED_DEL(sched, reg->timeout);
ast_string_field_free_memory(reg);
}
@@ -15469,7 +15466,7 @@ static const struct _map_x_s regstatestrings[] = {
{ REG_STATE_AUTHSENT, "Auth. Sent"},
{ REG_STATE_REGISTERED, "Registered"},
{ REG_STATE_REJECTED, "Rejected"},
{ REG_STATE_TIMEOUT, "Timeout"},
{ REG_STATE_TIMEOUT, "Registered"},/* Hidden state. We are renewing registration. */
{ REG_STATE_NOAUTH, "No Authentication"},
{ -1, NULL } /* terminator */
};
@@ -15485,22 +15482,22 @@ static void sip_publish_registry(const char *username, const char *domain, const
ast_system_publish_registry("SIP", username, domain, status, NULL);
}
/*! \brief Update registration with SIP Proxy.
/*!
* \brief Update registration with SIP Proxy.
*
* \details
* Called from the scheduler when the previous registration expires,
* so we don't have to cancel the pending event.
* We assume the reference so the sip_registry is valid, since it
* is stored in the scheduled event anyways.
*
* \note Run by the sched thread.
*/
static int sip_reregister(const void *data)
{
/* if we are here, we know that we need to reregister. */
struct sip_registry *r = (struct sip_registry *) data;
/* if we couldn't get a reference to the registry object, punt */
if (!r) {
return 0;
}
if (r->call && r->call->do_history) {
append_history(r->call, "RegistryRenew", "Account: %s@%s", r->username, r->hostname);
}
@@ -15512,8 +15509,25 @@ static int sip_reregister(const void *data)
r->expire = -1;
r->expiry = r->configured_expiry;
switch (r->regstate) {
case REG_STATE_UNREGISTERED:
case REG_STATE_REGSENT:
case REG_STATE_AUTHSENT:
break;
case REG_STATE_REJECTED:
case REG_STATE_NOAUTH:
case REG_STATE_FAILED:
/* Restarting registration as unregistered */
r->regstate = REG_STATE_UNREGISTERED;
break;
case REG_STATE_TIMEOUT:
case REG_STATE_REGISTERED:
/* Registration needs to be renewed. */
r->regstate = REG_STATE_TIMEOUT;
break;
}
__sip_do_register(r);
ao2_t_ref(r, -1, "unref the re-register scheduled event");
ao2_t_ref(r, -1, "Scheduled reregister timeout complete");
return 0;
}
@@ -15528,21 +15542,83 @@ static int __sip_do_register(struct sip_registry *r)
return res;
}
/*! \brief Registration timeout, register again
struct reregister_data {
struct sip_registry *reg;
int ms;
};
/* Run by the sched thread. */
static int __start_reregister_timeout(const void *data)
{
struct reregister_data *sched_data = (void *) data;
struct sip_registry *reg = sched_data->reg;
int ms = sched_data->ms;
ast_free(sched_data);
AST_SCHED_DEL_UNREF(sched, reg->expire,
ao2_t_ref(reg, -1, "Stop scheduled reregister timeout"));
ao2_t_ref(reg, +1, "Schedule reregister timeout");
reg->expire = ast_sched_add(sched, ms, sip_reregister, reg);
if (reg->expire < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule reregister timeout");
}
ao2_t_ref(reg, -1, "Start reregister timeout action");
return 0;
}
static void start_reregister_timeout(struct sip_registry *reg, int ms)
{
struct reregister_data *sched_data;
sched_data = ast_malloc(sizeof(*sched_data));
if (!sched_data) {
/* Uh Oh. Expect bad behavior. */
return;
}
sched_data->reg = reg;
sched_data->ms = ms;
ao2_t_ref(reg, +1, "Start reregister timeout action");
if (ast_sched_add(sched, 0, __start_reregister_timeout, sched_data) < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule start reregister timeout action");
ast_free(sched_data);
}
}
/*!
* \brief Registration request timeout, register again
*
* \details
* Registered as a timeout handler during transmit_register(),
* to retransmit the packet if a reply does not come back.
* This is called by the scheduler so the event is not pending anymore when
*
* \note This is called by the scheduler so the event is not pending anymore when
* we are called.
*
* \note Run by the sched thread.
*/
static int sip_reg_timeout(const void *data)
{
/* if we are here, our registration timed out, so we'll just do it over */
struct sip_registry *r = (struct sip_registry *)data; /* the ref count should have been bumped when the sched item was added */
struct sip_pvt *p;
/* if we couldn't get a reference to the registry object, punt */
if (!r) {
switch (r->regstate) {
case REG_STATE_UNREGISTERED:
case REG_STATE_REGSENT:
case REG_STATE_AUTHSENT:
case REG_STATE_TIMEOUT:
break;
default:
/*
* Registration completed because we got a request response
* and we couldn't stop the scheduled entry in time.
*/
r->timeout = -1;
ao2_t_ref(r, -1, "Scheduled register timeout completed early");
return 0;
}
@@ -15584,10 +15660,60 @@ static int sip_reg_timeout(const void *data)
ast_log(LOG_NOTICE, " -- Registration for '%s@%s' timed out, trying again (Attempt #%d)\n", r->username, r->hostname, r->regattempts);
}
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
ao2_t_ref(r, -1, "unreffing registry_unref r");
ao2_t_ref(r, -1, "Scheduled register timeout complete");
return 0;
}
/* Run by the sched thread. */
static int __stop_register_timeout(const void *data)
{
struct sip_registry *reg = (struct sip_registry *) data;
AST_SCHED_DEL_UNREF(sched, reg->timeout,
ao2_t_ref(reg, -1, "Stop scheduled register timeout"));
ao2_t_ref(reg, -1, "Stop register timeout action");
return 0;
}
static void stop_register_timeout(struct sip_registry *reg)
{
ao2_t_ref(reg, +1, "Stop register timeout action");
if (ast_sched_add(sched, 0, __stop_register_timeout, reg) < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule stop register timeout action");
}
}
/* Run by the sched thread. */
static int __start_register_timeout(const void *data)
{
struct sip_registry *reg = (struct sip_registry *) data;
AST_SCHED_DEL_UNREF(sched, reg->timeout,
ao2_t_ref(reg, -1, "Stop scheduled register timeout"));
ao2_t_ref(reg, +1, "Schedule register timeout");
reg->timeout = ast_sched_add(sched, global_reg_timeout * 1000, sip_reg_timeout, reg);
if (reg->timeout < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule register timeout");
}
ast_debug(1, "Scheduled a registration timeout for %s id #%d \n",
reg->hostname, reg->timeout);
ao2_t_ref(reg, -1, "Start register timeout action");
return 0;
}
static void start_register_timeout(struct sip_registry *reg)
{
ao2_t_ref(reg, +1, "Start register timeout action");
if (ast_sched_add(sched, 0, __start_register_timeout, reg) < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule start register timeout action");
}
}
static const char *sip_sanitized_host(const char *host)
{
struct ast_sockaddr addr = { { 0, 0, }, };
@@ -15701,16 +15827,9 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
* probably DNS. We need to reschedule a registration try */
dialog_unlink_all(p);
p = dialog_unref(p, "unref dialog after unlink_all");
if (r->timeout > -1) {
AST_SCHED_REPLACE_UNREF(r->timeout, sched, global_reg_timeout * 1000, sip_reg_timeout, r,
ao2_t_ref(_data, -1, "del for REPLACE of registry ptr"),
ao2_t_ref(r, -1, "object ptr dec when SCHED_REPLACE add failed"),
ao2_t_ref(r, +1, "add for REPLACE registry ptr"));
ast_log(LOG_WARNING, "Still have a registration timeout for %s@%s (create_addr() error), %d\n", r->username, r->hostname, r->timeout);
} else {
r->timeout = ast_sched_add(sched, global_reg_timeout * 1000, sip_reg_timeout, ao2_t_bump(r, "add for REPLACE registry ptr"));
ast_log(LOG_WARNING, "Probably a DNS error for registration to %s@%s, trying REGISTER again (after %d seconds)\n", r->username, r->hostname, global_reg_timeout);
}
ast_log(LOG_WARNING, "Probably a DNS error for registration to %s@%s, trying REGISTER again (after %d seconds)\n",
r->username, r->hostname, global_reg_timeout);
start_register_timeout(r);
r->regattempts++;
return 0;
}
@@ -15773,14 +15892,7 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
/* set up a timeout */
if (auth == NULL) {
if (r->timeout > -1) {
ast_log(LOG_WARNING, "Still have a registration timeout, #%d - deleting it\n", r->timeout);
}
AST_SCHED_REPLACE_UNREF(r->timeout, sched, global_reg_timeout * 1000, sip_reg_timeout, r,
ao2_t_ref(_data, -1, "reg ptr unrefed from del in SCHED_REPLACE"),
ao2_t_ref(r, -1, "reg ptr unrefed from add failure in SCHED_REPLACE"),
ao2_t_ref(r, +1, "reg ptr reffed from add in SCHED_REPLACE"));
ast_debug(1, "Scheduled a registration timeout for %s id #%d \n", r->hostname, r->timeout);
start_register_timeout(r);
}
snprintf(from, sizeof(from), "<sip:%s@%s>;tag=%s", r->username, S_OR(r->regdomain, sip_sanitized_host(p->tohost)), p->tag);
@@ -24047,8 +24159,8 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
break;
}
ast_log(LOG_WARNING, "Forbidden - wrong password on authentication for REGISTER for '%s' to '%s'\n", p->registry->username, p->registry->hostname);
AST_SCHED_DEL_UNREF(sched, r->timeout, ao2_t_ref(r, -1, "reg ptr unref from handle_response_register 403"));
r->regstate = REG_STATE_NOAUTH;
stop_register_timeout(r);
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
pvt_set_needdestroy(p, "received 403 response");
break;
@@ -24058,8 +24170,8 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
if (r->call)
r->call = dialog_unref(r->call, "unsetting registry->call pointer-- case 404");
r->regstate = REG_STATE_REJECTED;
stop_register_timeout(r);
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
AST_SCHED_DEL_UNREF(sched, r->timeout, ao2_t_ref(r, -1, "reg ptr unref from handle_response_register 404"));
break;
case 407: /* Proxy auth */
if (p->authtries == MAX_AUTHTRIES || do_register_auth(p, req, resp)) {
@@ -24078,7 +24190,6 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
case 423: /* Interval too brief */
r->expiry = atoi(sip_get_header(req, "Min-Expires"));
ast_log(LOG_WARNING, "Got 423 Interval too brief for service %s@%s, minimum is %d seconds\n", p->registry->username, p->registry->hostname, r->expiry);
AST_SCHED_DEL_UNREF(sched, r->timeout, ao2_t_ref(r, -1, "reg ptr unref from handle_response_register 423"));
if (r->call) {
r->call = dialog_unref(r->call, "unsetting registry->call pointer-- case 423");
pvt_set_needdestroy(p, "received 423 response");
@@ -24087,6 +24198,7 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
ast_log(LOG_WARNING, "Required expiration time from %s@%s is too high, giving up\n", p->registry->username, p->registry->hostname);
r->expiry = r->configured_expiry;
r->regstate = REG_STATE_REJECTED;
stop_register_timeout(r);
} else {
r->regstate = REG_STATE_UNREGISTERED;
transmit_register(r, SIP_REGISTER, NULL, NULL);
@@ -24102,8 +24214,8 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
if (r->call)
r->call = dialog_unref(r->call, "unsetting registry->call pointer-- case 4xx");
r->regstate = REG_STATE_REJECTED;
stop_register_timeout(r);
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
AST_SCHED_DEL_UNREF(sched, r->timeout, ao2_t_ref(r, -1, "reg ptr unref from handle_response_register 479"));
break;
case 200: /* 200 OK */
if (!r) {
@@ -24112,15 +24224,15 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
return 0;
}
r->regstate = REG_STATE_REGISTERED;
r->regtime = ast_tvnow(); /* Reset time of last successful registration */
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
r->regattempts = 0;
ast_debug(1, "Registration successful\n");
if (r->timeout > -1) {
ast_debug(1, "Cancelling timeout %d\n", r->timeout);
}
AST_SCHED_DEL_UNREF(sched, r->timeout, ao2_t_ref(r, -1, "reg ptr unref from handle_response_register 200"));
r->regstate = REG_STATE_REGISTERED;
stop_register_timeout(r);
r->regtime = ast_tvnow(); /* Reset time of last successful registration */
sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
r->regattempts = 0;
if (r->call)
r->call = dialog_unref(r->call, "unsetting registry->call pointer-- case 200");
ao2_t_replace(p->registry, NULL, "unref registry entry p->registry");
@@ -24174,10 +24286,7 @@ static int handle_response_register(struct sip_pvt *p, int resp, const char *res
r->refresh= (int) expires_ms / 1000;
/* Schedule re-registration before we expire */
AST_SCHED_REPLACE_UNREF(r->expire, sched, expires_ms, sip_reregister, r,
ao2_t_ref(_data, -1, "unref in REPLACE del fail"),
ao2_t_ref(r, -1, "unref in REPLACE add fail"),
ao2_t_ref(r, +1, "The Addition side of REPLACE"));
start_reregister_timeout(r, expires_ms);
}
return 1;
}
@@ -31606,9 +31715,11 @@ static void display_nat_warning(const char *cat, int reason, struct ast_flags *f
}
}
static int cleanup_registration(void *obj, void *arg, int flags)
/* Run by the sched thread. */
static int __cleanup_registration(const void *data)
{
struct sip_registry *reg = obj;
struct sip_registry *reg = (struct sip_registry *) data;
ao2_lock(reg);
if (reg->call) {
@@ -31617,12 +31728,12 @@ static int cleanup_registration(void *obj, void *arg, int flags)
dialog_unlink_all(reg->call);
reg->call = dialog_unref(reg->call, "remove iterator->call from registry traversal");
}
if (reg->expire > -1) {
AST_SCHED_DEL_UNREF(sched, reg->expire, ao2_t_ref(reg, -1, "reg ptr unref from reload config"));
}
if (reg->timeout > -1) {
AST_SCHED_DEL_UNREF(sched, reg->timeout, ao2_t_ref(reg, -1, "reg ptr unref from reload config"));
}
AST_SCHED_DEL_UNREF(sched, reg->expire,
ao2_t_ref(reg, -1, "Stop scheduled reregister timeout"));
AST_SCHED_DEL_UNREF(sched, reg->timeout,
ao2_t_ref(reg, -1, "Stop scheduled register timeout"));
if (reg->dnsmgr) {
ast_dnsmgr_release(reg->dnsmgr);
reg->dnsmgr = NULL;
@@ -31630,6 +31741,21 @@ static int cleanup_registration(void *obj, void *arg, int flags)
}
ao2_unlock(reg);
ao2_t_ref(reg, -1, "cleanup_registration action");
return 0;
}
static int cleanup_registration(void *obj, void *arg, int flags)
{
struct sip_registry *reg = obj;
ao2_t_ref(reg, +1, "cleanup_registration action");
if (ast_sched_add(sched, 0, __cleanup_registration, reg) < 0) {
/* Uh Oh. Expect bad behavior. */
ao2_t_ref(reg, -1, "Failed to schedule cleanup_registration action");
}
return CMP_MATCH;
}
@@ -33423,10 +33549,7 @@ static void sip_send_all_registers(void)
while ((iterator = ao2_t_iterator_next(&iter, "sip_send_all_registers iter"))) {
ao2_lock(iterator);
ms += regspacing;
AST_SCHED_REPLACE_UNREF(iterator->expire, sched, ms, sip_reregister, iterator,
ao2_t_ref(_data, -1, "REPLACE sched del decs the refcount"),
ao2_t_ref(iterator, -1, "REPLACE sched add failure decs the refcount"),
ao2_t_ref(iterator, +1, "REPLACE sched add incs the refcount"));
start_reregister_timeout(iterator, ms);
ao2_unlock(iterator);
ao2_t_ref(iterator, -1, "sip_send_all_registers iter");
}

3
channels/sip/include/sip.h
View File

@@ -547,8 +547,7 @@ enum sipregistrystate {
* recover (not sure how correctly).
*/
REG_STATE_TIMEOUT, /*!< Registration timed out
* \note XXX unused */
REG_STATE_TIMEOUT, /*!< Registration about to expire, renewing registration */
REG_STATE_NOAUTH, /*!< We have no accepted credentials
* \note fatal - no chance to proceed */