[asterisk-commits] pjsip distributor.c: Fix deadlock with TCP type transports. (asterisk[14])
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Wed Jul 5 15:59:00 CDT 2017
Jenkins2 has submitted this change and it was merged. ( https://gerrit.asterisk.org/5920 )
Change subject: pjsip_distributor.c: Fix deadlock with TCP type transports.
......................................................................
pjsip_distributor.c: Fix deadlock with TCP type transports.
When a SIP message comes in on a transport, pjproject obtains the lock on
the transport and pulls the data out of the socket. Unlike UDP, the TCP
transport does not allow concurrent access. Without concurrency the
transport lock is not released when the transport's message complete
callback is called. The processing continues and eventually Asterisk
starts processing the SIP message. The first thing Asterisk tries to do
is determine the associated dialog of the message to determine the
associated serializer. To get the associated serializer safely requires
us to get the dialog lock.
To send a request or response message for a dialog, pjproject obtains the
dialog lock and then obtains the transport lock. Deadlock can result
because of the opposite order the locks are obtained.
* Fix the deadlock by obtaining the serializer associated with the dialog
another way that doesn't involve obtaining the dialog lock. In this case,
we use an ao2 container to hold the associated endpoint and serializer.
The new locks are held a brief time and won't overlap other existing lock
times.
ASTERISK-27090 #close
Change-Id: I9ed63f4da9649e9db6ed4be29c360968917a89bd
---
M res/res_pjsip/pjsip_distributor.c
1 file changed, 174 insertions(+), 42 deletions(-)
Approvals:
Joshua Colp: Looks good to me, but someone else must approve
George Joseph: Looks good to me, approved
Jenkins2: Approved for Submit
diff --git a/res/res_pjsip/pjsip_distributor.c b/res/res_pjsip/pjsip_distributor.c
index cca26a8..d5a8c84 100644
--- a/res/res_pjsip/pjsip_distributor.c
+++ b/res/res_pjsip/pjsip_distributor.c
@@ -150,62 +150,189 @@
/*! Dialog-specific information the distributor uses */
struct distributor_dialog_data {
+ /*! dialog_associations ao2 container key */
+ pjsip_dialog *dlg;
/*! Serializer to distribute tasks to for this dialog */
struct ast_taskprocessor *serializer;
/*! Endpoint associated with this dialog */
struct ast_sip_endpoint *endpoint;
};
+#define DIALOG_ASSOCIATIONS_BUCKETS 251
+
+static struct ao2_container *dialog_associations;
+
/*!
* \internal
+ * \brief Compute a hash value on an arbitrary buffer.
+ * \since 13.17.0
*
- * \note Call this with the dialog locked
+ * \param[in] pos The buffer to add to the hash
+ * \param[in] len The buffer length to add to the hash
+ * \param[in] hash The hash value to add to
+ *
+ * \details
+ * This version of the function is for when you need to compute a
+ * hash of more than one buffer.
+ *
+ * This famous hash algorithm was written by Dan Bernstein and is
+ * commonly used.
+ *
+ * \sa http://www.cse.yorku.ca/~oz/hash.html
*/
-static struct distributor_dialog_data *distributor_dialog_data_alloc(pjsip_dialog *dlg)
+static int buf_hash_add(const char *pos, size_t len, int hash)
{
- struct distributor_dialog_data *dist;
+ while (len--) {
+ hash = hash * 33 ^ *pos++;
+ }
- dist = PJ_POOL_ZALLOC_T(dlg->pool, struct distributor_dialog_data);
- pjsip_dlg_set_mod_data(dlg, distributor_mod.id, dist);
+ return hash;
+}
- return dist;
+/*!
+ * \internal
+ * \brief Compute a hash value on an arbitrary buffer.
+ * \since 13.17.0
+ *
+ * \param[in] pos The buffer to add to the hash
+ * \param[in] len The buffer length to add to the hash
+ *
+ * \details
+ * This version of the function is for when you need to compute a
+ * hash of more than one buffer.
+ *
+ * This famous hash algorithm was written by Dan Bernstein and is
+ * commonly used.
+ *
+ * \sa http://www.cse.yorku.ca/~oz/hash.html
+ */
+static int buf_hash(const char *pos, size_t len)
+{
+ return buf_hash_add(pos, len, 5381);
+}
+
+static int dialog_associations_hash(const void *obj, int flags)
+{
+ const struct distributor_dialog_data *object;
+ union {
+ const pjsip_dialog *dlg;
+ const char buf[sizeof(pjsip_dialog *)];
+ } key;
+
+ switch (flags & OBJ_SEARCH_MASK) {
+ case OBJ_SEARCH_KEY:
+ key.dlg = obj;
+ break;
+ case OBJ_SEARCH_OBJECT:
+ object = obj;
+ key.dlg = object->dlg;
+ break;
+ default:
+ /* Hash can only work on something with a full key. */
+ ast_assert(0);
+ return 0;
+ }
+ return ast_str_hash_restrict(buf_hash(key.buf, sizeof(key.buf)));
+}
+
+static int dialog_associations_cmp(void *obj, void *arg, int flags)
+{
+ const struct distributor_dialog_data *object_left = obj;
+ const struct distributor_dialog_data *object_right = arg;
+ const pjsip_dialog *right_key = arg;
+ int cmp = 0;
+
+ switch (flags & OBJ_SEARCH_MASK) {
+ case OBJ_SEARCH_OBJECT:
+ right_key = object_right->dlg;
+ /* Fall through */
+ case OBJ_SEARCH_KEY:
+ if (object_left->dlg == right_key) {
+ cmp = CMP_MATCH;
+ }
+ break;
+ case OBJ_SEARCH_PARTIAL_KEY:
+ /* There is no such thing for this container. */
+ ast_assert(0);
+ break;
+ default:
+ cmp = 0;
+ break;
+ }
+ return cmp;
}
void ast_sip_dialog_set_serializer(pjsip_dialog *dlg, struct ast_taskprocessor *serializer)
{
struct distributor_dialog_data *dist;
- SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
- dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+ ao2_wrlock(dialog_associations);
+ dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY | OBJ_NOLOCK);
if (!dist) {
- dist = distributor_dialog_data_alloc(dlg);
+ if (serializer) {
+ dist = ao2_alloc(sizeof(*dist), NULL);
+ if (dist) {
+ dist->dlg = dlg;
+ dist->serializer = serializer;
+ ao2_link_flags(dialog_associations, dist, OBJ_NOLOCK);
+ ao2_ref(dist, -1);
+ }
+ }
+ } else {
+ ao2_lock(dist);
+ dist->serializer = serializer;
+ if (!dist->serializer && !dist->endpoint) {
+ ao2_unlink_flags(dialog_associations, dist, OBJ_NOLOCK);
+ }
+ ao2_unlock(dist);
+ ao2_ref(dist, -1);
}
- dist->serializer = serializer;
+ ao2_unlock(dialog_associations);
}
void ast_sip_dialog_set_endpoint(pjsip_dialog *dlg, struct ast_sip_endpoint *endpoint)
{
struct distributor_dialog_data *dist;
- SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
- dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+ ao2_wrlock(dialog_associations);
+ dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY | OBJ_NOLOCK);
if (!dist) {
- dist = distributor_dialog_data_alloc(dlg);
+ if (endpoint) {
+ dist = ao2_alloc(sizeof(*dist), NULL);
+ if (dist) {
+ dist->dlg = dlg;
+ dist->endpoint = endpoint;
+ ao2_link_flags(dialog_associations, dist, OBJ_NOLOCK);
+ ao2_ref(dist, -1);
+ }
+ }
+ } else {
+ ao2_lock(dist);
+ dist->endpoint = endpoint;
+ if (!dist->serializer && !dist->endpoint) {
+ ao2_unlink_flags(dialog_associations, dist, OBJ_NOLOCK);
+ }
+ ao2_unlock(dist);
+ ao2_ref(dist, -1);
}
- dist->endpoint = endpoint;
+ ao2_unlock(dialog_associations);
}
struct ast_sip_endpoint *ast_sip_dialog_get_endpoint(pjsip_dialog *dlg)
{
struct distributor_dialog_data *dist;
- SCOPED_LOCK(lock, dlg, pjsip_dlg_inc_lock, pjsip_dlg_dec_lock);
+ struct ast_sip_endpoint *endpoint;
- dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
- if (!dist || !dist->endpoint) {
- return NULL;
+ dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY);
+ if (dist) {
+ ao2_lock(dist);
+ endpoint = ao2_bump(dist->endpoint);
+ ao2_unlock(dist);
+ ao2_ref(dist, -1);
+ } else {
+ endpoint = NULL;
}
- ao2_ref(dist->endpoint, +1);
- return dist->endpoint;
+ return endpoint;
}
static pjsip_dialog *find_dialog(pjsip_rx_data *rdata)
@@ -237,7 +364,7 @@
pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_cancel_method) ||
rdata->msg_info.to->tag.slen != 0) {
dlg = pjsip_ua_find_dialog(&rdata->msg_info.cid->id, local_tag,
- remote_tag, PJ_TRUE);
+ remote_tag, PJ_FALSE);
if (dlg) {
return dlg;
}
@@ -275,11 +402,6 @@
pj_mutex_unlock(tsx->mutex);
#endif
- if (!dlg) {
- return NULL;
- }
-
- pjsip_dlg_inc_lock(dlg);
return dlg;
}
@@ -302,16 +424,7 @@
*/
static int pjstr_hash_add(pj_str_t *str, int hash)
{
- size_t len;
- const char *pos;
-
- len = pj_strlen(str);
- pos = pj_strbuf(str);
- while (len--) {
- hash = hash * 33 ^ *pos++;
- }
-
- return hash;
+ return buf_hash_add(pj_strbuf(str), pj_strlen(str), hash);
}
/*!
@@ -350,7 +463,7 @@
/* Compute the hash from the SIP message call-id and remote-tag */
hash = pjstr_hash(&rdata->msg_info.cid->id);
hash = pjstr_hash_add(remote_tag, hash);
- hash = abs(hash);
+ hash = ast_str_hash_restrict(hash);
serializer = ao2_bump(distributor_pool[hash % ARRAY_LEN(distributor_pool)]);
if (serializer) {
@@ -385,17 +498,18 @@
dlg = find_dialog(rdata);
if (dlg) {
- ast_debug(3, "Searching for serializer on dialog %s for %s\n",
+ ast_debug(3, "Searching for serializer associated with dialog %s for %s\n",
dlg->obj_name, pjsip_rx_data_get_info(rdata));
- dist = pjsip_dlg_get_mod_data(dlg, distributor_mod.id);
+ dist = ao2_find(dialog_associations, dlg, OBJ_SEARCH_KEY);
if (dist) {
+ ao2_lock(dist);
serializer = ao2_bump(dist->serializer);
+ ao2_unlock(dist);
if (serializer) {
- ast_debug(3, "Found serializer %s on dialog %s\n",
+ ast_debug(3, "Found serializer %s associated with dialog %s\n",
ast_taskprocessor_name(serializer), dlg->obj_name);
}
}
- pjsip_dlg_dec_lock(dlg);
}
if (serializer) {
@@ -417,6 +531,7 @@
/* We have a BYE or CANCEL request without a serializer. */
pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata,
PJSIP_SC_CALL_TSX_DOES_NOT_EXIST, NULL, NULL, NULL);
+ ao2_cleanup(dist);
return PJ_TRUE;
} else {
if (ast_taskprocessor_alert_get()) {
@@ -431,6 +546,7 @@
*/
ast_debug(3, "Taskprocessor overload alert: Ignoring '%s'.\n",
pjsip_rx_data_get_info(rdata));
+ ao2_cleanup(dist);
return PJ_TRUE;
}
@@ -438,10 +554,17 @@
serializer = ast_sip_get_distributor_serializer(rdata);
}
- pjsip_rx_data_clone(rdata, 0, &clone);
+ if (pjsip_rx_data_clone(rdata, 0, &clone) != PJ_SUCCESS) {
+ ast_taskprocessor_unreference(serializer);
+ ao2_cleanup(dist);
+ return PJ_TRUE;
+ }
if (dist) {
+ ao2_lock(dist);
clone->endpt_info.mod_data[endpoint_mod.id] = ao2_bump(dist->endpoint);
+ ao2_unlock(dist);
+ ao2_cleanup(dist);
}
if (ast_sip_push_task(serializer, distribute, clone)) {
@@ -1078,6 +1201,14 @@
return -1;
}
+ dialog_associations = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_RWLOCK, 0,
+ DIALOG_ASSOCIATIONS_BUCKETS, dialog_associations_hash, NULL,
+ dialog_associations_cmp);
+ if (!dialog_associations) {
+ ast_sip_destroy_distributor();
+ return -1;
+ }
+
if (distributor_pool_setup()) {
ast_sip_destroy_distributor();
return -1;
@@ -1156,5 +1287,6 @@
distributor_pool_shutdown();
+ ao2_cleanup(dialog_associations);
ao2_cleanup(unidentified_requests);
}
--
To view, visit https://gerrit.asterisk.org/5920
To unsubscribe, visit https://gerrit.asterisk.org/settings
Gerrit-Project: asterisk
Gerrit-Branch: 14
Gerrit-MessageType: merged
Gerrit-Change-Id: I9ed63f4da9649e9db6ed4be29c360968917a89bd
Gerrit-Change-Number: 5920
Gerrit-PatchSet: 2
Gerrit-Owner: Richard Mudgett <rmudgett at digium.com>
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Jenkins2
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Richard Mudgett <rmudgett at digium.com>
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