Merge changes from topic 'ASTERISK-24712' into 13

* changes:
  res_xmpp: Use incremental backoff when a read error occurs
  res_xmpp: Try to provide useful errors messages from OpenSSL
  res_xmpp: Correctly check return value of SSL_connect

res/res_xmpp.c

@@ -2623,12 +2623,31 @@ static int xmpp_client_request_tls(struct ast_xmpp_client *client, struct ast_xm
 #endif
 }
 
+#ifdef HAVE_OPENSSL
+static char *openssl_error_string(void)
+{
+	char *buf = NULL, *ret;
+	size_t len;
+	BIO *bio = BIO_new(BIO_s_mem());
+
+	ERR_print_errors(bio);
+	len = BIO_get_mem_data(bio, &buf);
+	ret = ast_calloc(1, len + 1);
+	if (ret) {
+		memcpy(ret, buf, len);
+	}
+	BIO_free(bio);
+	return ret;
+}
+#endif
+
 /*! \brief Internal function called when we receive a response to our TLS initiation request */
 static int xmpp_client_requested_tls(struct ast_xmpp_client *client, struct ast_xmpp_client_config *cfg, int type, iks *node)
 {
 #ifdef HAVE_OPENSSL
 	int sock;
 	long ssl_opts;
+	char *err;
 #endif
 
 	if (!strcmp(iks_name(node), "success")) {
@@ -2664,7 +2683,7 @@ static int xmpp_client_requested_tls(struct ast_xmpp_client *client, struct ast_
 		goto failure;
 	}
 
-	if (!SSL_connect(client->ssl_session)) {
+	if (SSL_connect(client->ssl_session) <= 0) {
 		goto failure;
 	}
 
@@ -2684,7 +2703,10 @@ static int xmpp_client_requested_tls(struct ast_xmpp_client *client, struct ast_
 	return 0;
 
 failure:
-	ast_log(LOG_ERROR, "TLS connection for client '%s' cannot be established. OpenSSL initialization failed.\n", client->name);
+	err = openssl_error_string();
+	ast_log(LOG_ERROR, "TLS connection for client '%s' cannot be established. "
+		"OpenSSL initialization failed: %s\n", client->name, err);
+	ast_free(err);
 	return -1;
 #endif
 }
@@ -3559,6 +3581,7 @@ int ast_xmpp_client_disconnect(struct ast_xmpp_client *client)
 {
 	if ((client->thread != AST_PTHREADT_NULL) && !pthread_equal(pthread_self(), client->thread)) {
 		xmpp_client_change_state(client, XMPP_STATE_DISCONNECTING);
+		pthread_cancel(client->thread);
 		pthread_join(client->thread, NULL);
 		client->thread = AST_PTHREADT_NULL;
 	}
@@ -3738,11 +3761,26 @@ static int xmpp_client_receive(struct ast_xmpp_client *client, unsigned int time
 	return IKS_OK;
 }
 
+static void sleep_with_backoff(unsigned int *sleep_time)
+{
+	/* We're OK with our thread dying here */
+	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
+
+	sleep(*sleep_time);
+	*sleep_time = MIN(60, *sleep_time * 2);
+
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
+}
+
 /*! \brief XMPP client connection thread */
 static void *xmpp_client_thread(void *data)
 {
 	struct ast_xmpp_client *client = data;
 	int res = IKS_NET_RWERR;
+	unsigned int sleep_time = 1;
+
+	/* We only allow cancellation while sleeping */
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
 
 	do {
 		if (client->state == XMPP_STATE_DISCONNECTING) {
@@ -3753,7 +3791,7 @@ static void *xmpp_client_thread(void *data)
 		if (res == IKS_NET_RWERR || client->timeout == 0) {
 			ast_debug(3, "[%s] Connecting\n", client->name);
 			if ((res = xmpp_client_reconnect(client)) != IKS_OK) {
-				sleep(4);
+				sleep_with_backoff(&sleep_time);
 				res = IKS_NET_RWERR;
 			}
 			continue;
@@ -3792,6 +3830,8 @@ static void *xmpp_client_thread(void *data)
 			}
 		} else if (res == IKS_NET_RWERR) {
 			ast_log(LOG_WARNING, "[%s] Socket read error\n", client->name);
+			ast_xmpp_client_disconnect(client);
+			sleep_with_backoff(&sleep_time);
 		} else if (res == IKS_NET_NOSOCK) {
 			ast_log(LOG_WARNING, "[%s] No socket\n", client->name);
 		} else if (res == IKS_NET_NOCONN) {
@@ -3804,6 +3844,8 @@ static void *xmpp_client_thread(void *data)
 			ast_log(LOG_WARNING, "[%s] Dropped?\n", client->name);
 		} else if (res == IKS_NET_UNKNOWN) {
 			ast_debug(5, "[%s] Unknown\n", client->name);
+		} else if (res == IKS_OK) {
+			sleep_time = 1;
 		}
 
 	} while (1);