[RFC PATCH] ModemManager: fix USSD reception, network notifications, and network requests

[Dan Williams <dcbw redhat com>]

RFC patch; I'm tired and don't want to look at this anymore so somebody
else double-check the cases for me.  Because the code was sending the
USSD request with a "notify me via unsolicited result code" tag, the
response could come from any port, and in was coming from other ports on
various devices.  But the code expected the response on the main port,
thus it got lost.

So turn the USSD response processing into an unsolicited command handler
instead, which allows us to process the response no matter where it
comes from.  This patch also enables network-initiated USSD
notifications and requests since that's easy to add once the first thing
here is done.

I'm somewhat wary about having to cache the MMCallbackInfo from
user-originated requests, since tracking the lifetime of those is easy
to screw up.  So any double-checking of that would be much appreciated.

---
diff --git a/src/mm-generic-gsm.c b/src/mm-generic-gsm.c
index bc718d1..d814c57 100644
--- a/src/mm-generic-gsm.c
+++ b/src/mm-generic-gsm.c
@@ -120,7 +120,11 @@ typedef struct {
     gboolean loc_enabled;
     gboolean loc_signal;
 
+    gboolean ussd_enabled;
+    MMCallbackInfo *pending_ussd_info;
     MMModemGsmUssdState ussd_state;
+    char *ussd_network_request;
+    char *ussd_network_notification;
 
     /* SMS */
     GHashTable *sms_present;
@@ -174,6 +178,10 @@ static void cmti_received (MMAtSerialPort *port,
                            GMatchInfo *info,
                            gpointer user_data);
 
+static void cusd_received (MMAtSerialPort *port,
+                           GMatchInfo *info,
+                           gpointer user_data);
+
 #define GS_HASH_TAG "get-sms"
 static GValue *simple_string_value (const char *str);
 static GValue *simple_uint_value (guint32 i);
@@ -844,6 +852,10 @@ mm_generic_gsm_grab_port (MMGenericGsm *self,
         mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (port), regex, cmti_received, self, NULL);
         g_regex_unref (regex);
 
+        regex = g_regex_new ("\\r\\n\\+CUSD:\\s*(.*)\\r\\n", G_REGEX_RAW | G_REGEX_OPTIMIZE, 0, NULL);
+        mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (port), regex, cusd_received, self, NULL);
+        g_regex_unref (regex);
+
         if (ptype == MM_PORT_TYPE_PRIMARY) {
             priv->primary = MM_AT_SERIAL_PORT (port);
             if (!priv->data) {
@@ -1412,6 +1424,21 @@ cind_cb (MMAtSerialPort *port,
     }
 }
 
+static void
+cusd_enable_cb (MMAtSerialPort *port,
+                GString *response,
+                GError *error,
+                gpointer user_data)
+{
+    if (error) {
+        mm_warn ("(%s): failed to enable USSD notifications.",
+                 mm_port_get_device (MM_PORT (port)));
+        return;
+    }
+
+    MM_GENERIC_GSM_GET_PRIVATE (user_data)->ussd_enabled = TRUE;
+}
+
 void
 mm_generic_gsm_enable_complete (MMGenericGsm *self,
                                 GError *error,
@@ -1462,6 +1489,9 @@ mm_generic_gsm_enable_complete (MMGenericGsm *self,
         mm_at_serial_port_queue_command (priv->primary, cmd, 3, NULL, NULL);
     g_free (cmd);
 
+    /* Enable USSD notifications */
+    mm_at_serial_port_queue_command (priv->primary, "+CUSD=1", 3, cusd_enable_cb, self);
+
     mm_at_serial_port_queue_command (priv->primary, "+CIND=?", 3, cind_cb, self);
 
     /* Try one more time to get the SIM ID */
@@ -1689,6 +1719,11 @@ disable_flash_done (MMSerialPort *port,
     mm_at_serial_port_queue_command (MM_AT_SERIAL_PORT (port), "+CREG=0", 3, NULL, NULL);
     mm_at_serial_port_queue_command (MM_AT_SERIAL_PORT (port), "+CGREG=0", 3, NULL, NULL);
 
+    if (priv->ussd_enabled) {
+        mm_at_serial_port_queue_command (MM_AT_SERIAL_PORT (port), "+CUSD=0", 3, NULL, NULL);
+        priv->ussd_enabled = FALSE;
+    }
+
     if (priv->cmer_enabled) {
         mm_at_serial_port_queue_command (MM_AT_SERIAL_PORT (port), "+CMER=0", 3, NULL, NULL);
 
@@ -1732,6 +1767,8 @@ disable (MMModem *modem,
 
     mm_generic_gsm_pending_registration_stop (MM_GENERIC_GSM (modem));
 
+    mm_generic_gsm_ussd_cleanup (MM_GENERIC_GSM (modem));
+
     if (priv->poll_id) {
         g_source_remove (priv->poll_id);
         priv->poll_id = 0;
@@ -4676,93 +4713,171 @@ ussd_update_state (MMGenericGsm *self, MMModemGsmUssdState new_state)
     }
 }
 
+void
+mm_generic_gsm_ussd_cleanup (MMGenericGsm *self)
+{
+    MMGenericGsmPrivate *priv = MM_GENERIC_GSM_GET_PRIVATE (self);
+
+    if (priv->pending_ussd_info) {
+        /* And schedule the callback */
+        g_clear_error (&priv->pending_ussd_info->error);
+        priv->pending_ussd_info->error = g_error_new_literal (MM_MODEM_ERROR,
+                                                              MM_MODEM_ERROR_GENERAL,
+                                                              "USSD session terminated without reply.");
+        mm_callback_info_schedule (priv->pending_ussd_info);
+        priv->pending_ussd_info = NULL;
+    }
+
+    ussd_update_state (self, MM_MODEM_GSM_USSD_STATE_IDLE);
+
+    g_free (priv->ussd_network_request);
+    priv->ussd_network_request = NULL;
+    g_object_notify (G_OBJECT (self), MM_MODEM_GSM_USSD_NETWORK_REQUEST);
+
+    g_free (priv->ussd_network_notification);
+    priv->ussd_network_notification = NULL;
+    g_object_notify (G_OBJECT (self), MM_MODEM_GSM_USSD_NETWORK_NOTIFICATION);
+}
+
+static char *
+decode_ussd_response (const char *reply, MMModemCharset cur_charset)
+{
+    char **items, **iter, *p;
+    char *str = NULL;
+    gint encoding = -1;
+
+    /* Look for the first ',' */
+    p = strchr (reply, ',');
+    if (p == NULL)
+        return NULL;
+
+    items = g_strsplit_set (p + 1, " ,", -1);
+    for (iter = items; iter && *iter; iter++) {
+        if (*iter[0] == '\0')
+            continue;
+        if (str == NULL)
+            str = *iter;
+        else if (encoding == -1) {
+            encoding = atoi (*iter);
+            mm_dbg ("USSD data coding scheme %d", encoding);
+            break;  /* All done */
+        }
+    }
+
+    /* Strip quotes */
+    if (str[0] == '"')
+        str++;
+    p = strchr (str, '"');
+    if (p)
+        *p = '\0';
+
+    /* FIXME: actually use the given encoding scheme */
+    return mm_modem_charset_hex_to_utf8 (str, cur_charset);
+}
+
 static void
-ussd_send_done (MMAtSerialPort *port,
-                GString *response,
-                GError *error,
-                gpointer user_data)
+cusd_received (MMAtSerialPort *port,
+               GMatchInfo *info,
+               gpointer user_data)
 {
-    MMCallbackInfo *info = (MMCallbackInfo *) user_data;
-    MMGenericGsmPrivate *priv;
+    MMGenericGsm *self = MM_GENERIC_GSM (user_data);
+    MMGenericGsmPrivate *priv = MM_GENERIC_GSM_GET_PRIVATE (self);
+    GError *error = NULL;
     gint status;
-    gboolean parsed = FALSE;
     MMModemGsmUssdState ussd_state = MM_MODEM_GSM_USSD_STATE_IDLE;
-    const char *str, *start = NULL, *end = NULL;
     char *reply = NULL, *converted;
 
-    /* If the modem has already been removed, return without
-     * scheduling callback */
-    if (mm_callback_info_check_modem_removed (info))
+    reply = g_match_info_fetch (info, 1);
+    if (!reply || !isdigit (*reply)) {
+        mm_warn ("Recieved invalid USSD response: '%s'", reply ? reply : "(none)");
+        g_free (reply);
         return;
-
-    if (error) {
-        info->error = g_error_copy (error);
-        goto done;
     }
 
-    priv = MM_GENERIC_GSM_GET_PRIVATE (info->modem);
-    ussd_state = priv->ussd_state;
-
-    str = mm_strip_tag (response->str, "+CUSD:");
-    if (!str || !isdigit (*str))
-        goto done;
-
-    status = g_ascii_digit_value (*str);
+    status = g_ascii_digit_value (*reply);
     switch (status) {
     case 0: /* no further action required */
-        ussd_state = MM_MODEM_GSM_USSD_STATE_IDLE;
+        converted = decode_ussd_response (reply, priv->cur_charset);
+        if (priv->pending_ussd_info) {
+            /* Response to the user's request */
+            mm_callback_info_set_result (priv->pending_ussd_info, converted, g_free);
+        } else {
+            /* Network-initiated USSD-Notify */
+            g_free (priv->ussd_network_notification);
+            priv->ussd_network_notification = converted;
+            g_object_notify (G_OBJECT (self), MM_MODEM_GSM_USSD_NETWORK_NOTIFICATION);
+        }
         break;
     case 1: /* further action required */
         ussd_state = MM_MODEM_GSM_USSD_STATE_USER_RESPONSE;
+        converted = decode_ussd_response (reply, priv->cur_charset);
+        if (priv->pending_ussd_info) {
+            mm_callback_info_set_result (priv->pending_ussd_info, converted, g_free);
+        } else {
+            /* Network-initiated USSD-Request */
+            g_free (priv->ussd_network_request);
+            priv->ussd_network_request = converted;
+            g_object_notify (G_OBJECT (self), MM_MODEM_GSM_USSD_NETWORK_REQUEST);
+        }
         break;
     case 2:
-        info->error = g_error_new (MM_MODEM_ERROR,
-                                   MM_MODEM_ERROR_GENERAL,
-                                   "USSD terminated by network.");
-        ussd_state = MM_MODEM_GSM_USSD_STATE_IDLE;
+        error = g_error_new_literal (MM_MODEM_ERROR,
+                                     MM_MODEM_ERROR_GENERAL,
+                                     "USSD terminated by network.");
         break;
     case 4:
-        info->error = g_error_new (MM_MODEM_ERROR,
-                                   MM_MODEM_ERROR_GENERAL,
-                                   "Operiation not supported.");
-        ussd_state = MM_MODEM_GSM_USSD_STATE_IDLE;
+        error = g_error_new_literal (MM_MODEM_ERROR,
+                                     MM_MODEM_ERROR_GENERAL,
+                                     "Operation not supported.");
         break;
     default:
-        info->error = g_error_new (MM_MODEM_ERROR,
-                                   MM_MODEM_ERROR_GENERAL,
-                                   "Unknown USSD reply %d", status);
-        ussd_state = MM_MODEM_GSM_USSD_STATE_IDLE;
+        error = g_error_new (MM_MODEM_ERROR,
+                             MM_MODEM_ERROR_GENERAL,
+                             "Unhandled USSD reply %d", status);
         break;
     }
-    if (info->error)
-        goto done;
 
-    /* look for the reply */
-    if ((start = strchr (str, '"')) && (end = strrchr (str, '"')) && (start != end))
-        reply = g_strndup (start + 1, end - start -1);
+    ussd_update_state (self, ussd_state);
 
-    if (reply) {
-        /* look for the reply data coding scheme */
-        if ((start = strrchr (end, ',')) != NULL)
-            mm_dbg ("USSD data coding scheme %d", atoi (start + 1));
-
-        converted = mm_modem_charset_hex_to_utf8 (reply, priv->cur_charset);
-        mm_callback_info_set_result (info, converted, g_free);
-        parsed = TRUE;
-        g_free (reply);
+    if (priv->pending_ussd_info) {
+        if (error)
+            priv->pending_ussd_info->error = g_error_copy (error);
+        mm_callback_info_schedule (priv->pending_ussd_info);
+        priv->pending_ussd_info = NULL;
     }
 
-done:
-    if (!parsed && !info->error) {
-        info->error = g_error_new (MM_MODEM_ERROR,
-                                   MM_MODEM_ERROR_GENERAL,
-                                   "Could not parse USSD reply '%s'",
-                                   response->str);
+    g_clear_error (&error);
+    g_free (reply);
+}
+
+static void
+ussd_send_done (MMAtSerialPort *port,
+                GString *response,
+                GError *error,
+                gpointer user_data)
+{
+    MMCallbackInfo *info = (MMCallbackInfo *) user_data;
+    MMGenericGsmPrivate *priv;
+
+    /* If the modem has already been removed, return without
+     * scheduling callback */
+    if (mm_callback_info_check_modem_removed (info))
+        return;
+
+    priv = MM_GENERIC_GSM_GET_PRIVATE (info->modem);
+
+    if (error) {
+        /* Some immediate error happened when sending the USSD request */
+        info->error = g_error_copy (error);
+        priv->pending_ussd_info = NULL;
+        mm_callback_info_schedule (info);
+
+        ussd_update_state (MM_GENERIC_GSM (info->modem), MM_MODEM_GSM_USSD_STATE_IDLE);
     }
-    mm_callback_info_schedule (info);
 
-    if (info->modem)
-        ussd_update_state (MM_GENERIC_GSM (info->modem), ussd_state);
+    /* Otherwise if no error wait for the response to show up via the 
+     * unsolicited response code.
+     */
 }
 
 static void
@@ -4779,6 +4894,8 @@ ussd_send (MMModemGsmUssd *modem,
     MMAtSerialPort *port;
     gboolean success;
 
+    g_warn_if_fail (priv->pending_ussd_info == NULL);
+
     info = mm_callback_info_string_new (MM_MODEM (modem), callback, user_data);
 
     port = mm_generic_gsm_get_best_at_port (MM_GENERIC_GSM (modem), &info->error);
@@ -4787,6 +4904,9 @@ ussd_send (MMModemGsmUssd *modem,
         return;
     }
 
+    /* Cache the callback info since the response is an unsolicited one */
+    priv->pending_ussd_info = info;
+
     /* encode to cur_charset */
     success = mm_modem_charset_byte_array_append (ussd_command, command, FALSE, priv->cur_charset);
     g_warn_if_fail (success == TRUE);
@@ -5737,10 +5857,10 @@ get_property (GObject *object, guint prop_id,
         g_value_set_string (value, ussd_state_to_string (priv->ussd_state));
         break;
     case MM_GENERIC_GSM_PROP_USSD_NETWORK_REQUEST:
-        g_value_set_string (value, "");
+        g_value_set_string (value, priv->ussd_network_request);
         break;
     case MM_GENERIC_GSM_PROP_USSD_NETWORK_NOTIFICATION:
-        g_value_set_string (value, "");
+        g_value_set_string (value, priv->ussd_network_notification);
         break;
     case MM_GENERIC_GSM_PROP_FLOW_CONTROL_CMD:
         /* By default, try to set XOFF/XON flow control */
@@ -5769,6 +5889,7 @@ finalize (GObject *object)
     MMGenericGsmPrivate *priv = MM_GENERIC_GSM_GET_PRIVATE (object);
 
     mm_generic_gsm_pending_registration_stop (MM_GENERIC_GSM (object));
+    mm_generic_gsm_ussd_cleanup (MM_GENERIC_GSM (object));
 
     if (priv->pin_check_timeout) {
         g_source_remove (priv->pin_check_timeout);
diff --git a/src/mm-generic-gsm.h b/src/mm-generic-gsm.h
index 5afab3c..57b65bf 100644
--- a/src/mm-generic-gsm.h
+++ b/src/mm-generic-gsm.h
@@ -159,6 +159,8 @@ MMModem *mm_generic_gsm_new (const char *device,
 
 void mm_generic_gsm_pending_registration_stop (MMGenericGsm *modem);
 
+void mm_generic_gsm_ussd_cleanup (MMGenericGsm *modem);
+
 gint mm_generic_gsm_get_cid (MMGenericGsm *modem);
 
 void mm_generic_gsm_set_reg_status (MMGenericGsm *modem,