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Fix more deadlocks in chan_iax2 that were introduced by making frame handling

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and scheduling multi-threaded.  Unfortunately, we have to do some expensive
deadlock avoidance when queueing frames on to the ast_channel owner of the IAX2
pvt struct.  This was already handled for regular frames, but ast_queue_hangup
and ast_queue_control were still used directly.  Making these changes introduced
even more places where the IAX2 pvt struct can disappear in the context of a
function holding its lock due to calling a function that has to unlock/lock it
to avoid deadlocks.  I went through and fixed all of these places to account for
this possibility.
(issue #10362, patch by me)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@79756 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Russell Bryant
2007-08-16 21:29:24 +00:00
parent 6ec280adfc
commit 0dbd8e04af
1 changed files with 164 additions and 12 deletions
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176
channels/chan_iax2.c
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@@ -1344,7 +1344,7 @@ static void iax2_frame_free(struct iax_frame *fr)
/*!
* \brief Queue a frame to a call's owning asterisk channel
*
* \note This function assumes that iaxsl[callno] is locked when called.
* \pre This function assumes that iaxsl[callno] is locked when called.
*
* \note IMPORTANT NOTE!!! Any time this function is used, even if iaxs[callno]
* was valid before calling it, it may no longer be valid after calling it.
@@ -1353,7 +1353,6 @@ static void iax2_frame_free(struct iax_frame *fr)
*/
static int iax2_queue_frame(int callno, struct ast_frame *f)
{
/* Assumes lock for callno is already held... */
for (;;) {
if (iaxs[callno] && iaxs[callno]->owner) {
if (ast_mutex_trylock(&iaxs[callno]->owner->lock)) {
@@ -1372,6 +1371,72 @@ static int iax2_queue_frame(int callno, struct ast_frame *f)
return 0;
}
/*!
* \brief Queue a hangup frame on the ast_channel owner
*
* This function queues a hangup frame on the owner of the IAX2 pvt struct that
* is active for the given call number.
*
* \pre Assumes lock for callno is already held.
*
* \note IMPORTANT NOTE!!! Any time this function is used, even if iaxs[callno]
* was valid before calling it, it may no longer be valid after calling it.
* This function may unlock and lock the mutex associated with this callno,
* meaning that another thread may grab it and destroy the call.
*/
static int iax2_queue_hangup(int callno)
{
for (;;) {
if (iaxs[callno] && iaxs[callno]->owner) {
if (ast_mutex_trylock(&iaxs[callno]->owner->lock)) {
/* Avoid deadlock by pausing and trying again */
ast_mutex_unlock(&iaxsl[callno]);
usleep(1);
ast_mutex_lock(&iaxsl[callno]);
} else {
ast_queue_hangup(iaxs[callno]->owner);
ast_mutex_unlock(&iaxs[callno]->owner->lock);
break;
}
} else
break;
}
return 0;
}
/*!
* \brief Queue a control frame on the ast_channel owner
*
* This function queues a control frame on the owner of the IAX2 pvt struct that
* is active for the given call number.
*
* \pre Assumes lock for callno is already held.
*
* \note IMPORTANT NOTE!!! Any time this function is used, even if iaxs[callno]
* was valid before calling it, it may no longer be valid after calling it.
* This function may unlock and lock the mutex associated with this callno,
* meaning that another thread may grab it and destroy the call.
*/
static int iax2_queue_control_data(int callno,
enum ast_control_frame_type control, const void *data, size_t datalen)
{
for (;;) {
if (iaxs[callno] && iaxs[callno]->owner) {
if (ast_mutex_trylock(&iaxs[callno]->owner->lock)) {
/* Avoid deadlock by pausing and trying again */
ast_mutex_unlock(&iaxsl[callno]);
usleep(1);
ast_mutex_lock(&iaxsl[callno]);
} else {
ast_queue_control_data(iaxs[callno]->owner, control, data, datalen);
ast_mutex_unlock(&iaxs[callno]->owner->lock);
break;
}
} else
break;
}
return 0;
}
static void destroy_firmware(struct iax_firmware *cur)
{
/* Close firmware */
@@ -1774,6 +1839,10 @@ static void iax2_destroy_helper(struct chan_iax2_pvt *pvt)
pvt->jbid = -1;
}
/*!
* \note Since this function calls iax2_queue_hangup(), the pvt struct
* for the given call number may disappear during its execution.
*/
static int iax2_predestroy(int callno)
{
struct ast_channel *c;
@@ -1787,9 +1856,8 @@ static int iax2_predestroy(int callno)
}
c = pvt->owner;
if (c) {
c->_softhangup |= AST_SOFTHANGUP_DEV;
c->tech_pvt = NULL;
ast_queue_hangup(c);
iax2_queue_hangup(callno);
pvt->owner = NULL;
ast_module_unref(ast_module_info->self);
}
@@ -1829,7 +1897,8 @@ retry:
if (owner) {
/* If there's an owner, prod it to give up */
owner->_softhangup |= AST_SOFTHANGUP_DEV;
/* It is ok to use ast_queue_hangup() here instead of iax2_queue_hangup()
* because we already hold the owner channel lock. */
ast_queue_hangup(owner);
}
@@ -3031,12 +3100,17 @@ static int iax2_hangup(struct ast_channel *c)
alreadygone = ast_test_flag(iaxs[callno], IAX_ALREADYGONE);
/* Send the hangup unless we have had a transmission error or are already gone */
iax_ie_append_byte(&ied, IAX_IE_CAUSECODE, (unsigned char)c->hangupcause);
if (!iaxs[callno]->error && !alreadygone)
if (!iaxs[callno]->error && !alreadygone) {
send_command_final(iaxs[callno], AST_FRAME_IAX, IAX_COMMAND_HANGUP, 0, ied.buf, ied.pos, -1);
if (!iaxs[callno]) {
ast_mutex_unlock(&iaxsl[callno]);
return 0;
}
}
/* Explicitly predestroy it */
iax2_predestroy(callno);
/* If we were already gone to begin with, destroy us now */
if (alreadygone) {
if (alreadygone && iaxs[callno]) {
ast_log(LOG_DEBUG, "Really destroying %s now...\n", c->name);
iax2_destroy(callno);
}
@@ -4642,10 +4716,18 @@ static int send_command_locked(unsigned short callno, char type, int command, un
return res;
}
/*!
* \note Since this function calls iax2_predestroy() -> iax2_queue_hangup(),
* the pvt struct for the given call number may disappear during its
* execution.
*/
static int send_command_final(struct chan_iax2_pvt *i, char type, int command, unsigned int ts, const unsigned char *data, int datalen, int seqno)
{
int call_num = i->callno;
/* It is assumed that the callno has already been locked */
iax2_predestroy(i->callno);
if (!iaxs[call_num])
return -1;
return __send_command(i, type, command, ts, data, datalen, seqno, 0, 0, 1);
}
@@ -4902,12 +4984,19 @@ static void merge_encryption(struct chan_iax2_pvt *p, unsigned int enc)
}
}
static int authenticate_request(struct chan_iax2_pvt *p)
/*!
* \pre iaxsl[call_num] is locked
*
* \note Since this function calls send_command_final(), the pvt struct for the given
* call number may disappear while executing this function.
*/
static int authenticate_request(int call_num)
{
struct iax2_user *user = NULL;
struct iax_ie_data ied;
int res = -1, authreq_restrict = 0;
char challenge[10];
struct chan_iax2_pvt *p = iaxs[call_num];
memset(&ied, 0, sizeof(ied));
@@ -5682,6 +5771,12 @@ static void reg_source_db(struct iax2_peer *p)
}
}
/*!
* \pre iaxsl[callno] is locked
*
* \note Since this function calls send_command_final(), the pvt struct for
* the given call number may disappear while executing this function.
*/
static int update_registry(struct sockaddr_in *sin, int callno, char *devtype, int fd, unsigned short refresh)
{
/* Called from IAX thread only, with proper iaxsl lock */
@@ -6991,9 +7086,13 @@ retryowner:
if (ies.musiconhold) {
if (iaxs[fr->callno]->owner && ast_bridged_channel(iaxs[fr->callno]->owner)) {
const char *mohsuggest = iaxs[fr->callno]->mohsuggest;
ast_queue_control_data(iaxs[fr->callno]->owner, AST_CONTROL_HOLD,
iax2_queue_control_data(fr->callno, AST_CONTROL_HOLD,
S_OR(mohsuggest, NULL),
!ast_strlen_zero(mohsuggest) ? strlen(mohsuggest) + 1 : 0);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
}
}
}
@@ -7010,8 +7109,13 @@ retryowner:
}
ast_clear_flag(iaxs[fr->callno], IAX_QUELCH);
if (iaxs[fr->callno]->owner && ast_bridged_channel(iaxs[fr->callno]->owner))
ast_queue_control(iaxs[fr->callno]->owner, AST_CONTROL_UNHOLD);
if (iaxs[fr->callno]->owner && ast_bridged_channel(iaxs[fr->callno]->owner)) {
iax2_queue_control_data(fr->callno, AST_CONTROL_UNHOLD, NULL, 0);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
}
}
break;
case IAX_COMMAND_TXACC:
@@ -7083,6 +7187,10 @@ retryowner:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "No such context/extension");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_NO_ROUTE_DESTINATION);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
if (authdebug)
ast_log(LOG_NOTICE, "Rejected connect attempt from %s, request '%s@%s' does not exist\n", ast_inet_ntoa(sin.sin_addr), iaxs[fr->callno]->exten, iaxs[fr->callno]->context);
} else {
@@ -7126,6 +7234,10 @@ retryowner:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "Unable to negotiate codec");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_BEARERCAPABILITY_NOTAVAIL);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
if (authdebug) {
if(ast_test_flag(iaxs[fr->callno], IAX_CODEC_NOCAP))
ast_log(LOG_NOTICE, "Rejected connect attempt from %s, requested 0x%x incompatible with our capability 0x%x.\n", ast_inet_ntoa(sin.sin_addr), iaxs[fr->callno]->peerformat, iaxs[fr->callno]->capability);
@@ -7167,6 +7279,10 @@ retryowner:
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_BEARERCAPABILITY_NOTAVAIL);
ast_log(LOG_ERROR, "No best format in 0x%x???\n", iaxs[fr->callno]->peercapability & iaxs[fr->callno]->capability);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
if (authdebug)
ast_log(LOG_NOTICE, "Rejected connect attempt from %s, requested/capability 0x%x/0x%x incompatible with our capability 0x%x.\n", ast_inet_ntoa(sin.sin_addr), iaxs[fr->callno]->peerformat, iaxs[fr->callno]->peercapability, iaxs[fr->callno]->capability);
ast_set_flag(iaxs[fr->callno], IAX_ALREADYGONE);
@@ -7216,8 +7332,12 @@ retryowner:
merge_encryption(iaxs[fr->callno],ies.encmethods);
else
iaxs[fr->callno]->encmethods = 0;
if (!authenticate_request(iaxs[fr->callno]))
if (!authenticate_request(fr->callno) && iaxs[fr->callno])
ast_set_flag(&iaxs[fr->callno]->state, IAX_STATE_AUTHENTICATED);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
break;
case IAX_COMMAND_DPREQ:
/* Request status in the dialplan */
@@ -7308,6 +7428,10 @@ retryowner:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "Unable to negotiate codec");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_BEARERCAPABILITY_NOTAVAIL);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
if (authdebug)
ast_log(LOG_NOTICE, "Rejected call to %s, format 0x%x incompatible with our capability 0x%x.\n", ast_inet_ntoa(sin.sin_addr), iaxs[fr->callno]->peerformat, iaxs[fr->callno]->capability);
} else {
@@ -7350,6 +7474,10 @@ retryowner2:
case IAX_COMMAND_POKE:
/* Send back a pong packet with the original timestamp */
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_PONG, fr->ts, NULL, 0, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
break;
case IAX_COMMAND_PING:
{
@@ -7470,6 +7598,10 @@ retryowner2:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "No such context/extension");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_NO_ROUTE_DESTINATION);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
} else {
/* Select an appropriate format */
if(ast_test_flag(iaxs[fr->callno], IAX_CODEC_NOPREFS)) {
@@ -7516,6 +7648,10 @@ retryowner2:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "Unable to negotiate codec");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_BEARERCAPABILITY_NOTAVAIL);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
} else {
/* Pick one... */
if(ast_test_flag(iaxs[fr->callno], IAX_CODEC_NOCAP)) {
@@ -7556,6 +7692,10 @@ retryowner2:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "Unable to negotiate codec");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_BEARERCAPABILITY_NOTAVAIL);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
}
}
}
@@ -7608,6 +7748,10 @@ retryowner2:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "No such context/extension");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_NO_ROUTE_DESTINATION);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
} else {
ast_set_flag(&iaxs[fr->callno]->state, IAX_STATE_STARTED);
if (option_verbose > 2)
@@ -7702,6 +7846,10 @@ retryowner2:
iax_ie_append_str(&ied0, IAX_IE_CAUSE, "No authority found");
iax_ie_append_byte(&ied0, IAX_IE_CAUSECODE, AST_CAUSE_FACILITY_NOT_SUBSCRIBED);
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_REJECT, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
}
break;
case IAX_COMMAND_TXREJ:
@@ -7812,6 +7960,10 @@ retryowner2:
send_command_final(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_FWDATA, 0, ied0.buf, ied0.pos, -1);
else
send_command(iaxs[fr->callno], AST_FRAME_IAX, IAX_COMMAND_FWDATA, 0, ied0.buf, ied0.pos, -1);
if (!iaxs[fr->callno]) {
ast_mutex_unlock(&iaxsl[fr->callno]);
return 1;
}
break;
default:
ast_log(LOG_DEBUG, "Unknown IAX command %d on %d/%d\n", f.subclass, fr->callno, iaxs[fr->callno]->peercallno);