From d2748e1952c282ce82e93daaeb2f25bb10ce46ab Mon Sep 17 00:00:00 2001
From: Dylan Van Assche <me@dylanvanassche.be>
Date: Sat, 16 Apr 2022 20:29:54 +0200
Subject: [PATCH 25/26] bluetooth: support ATD$number;

Start a call when HF sends 'ATD$number;'
This AT command is only available when ModemManager is present.
Number is filtered for any invalid characters, if an invalid character
is found, the call is aborted and an error is returned.
---
 src/modules/bluetooth/backend-native.c | 57 ++++++++++++++++++++++++++
 src/modules/bluetooth/bluez5-util.h    |  1 +
 2 files changed, 58 insertions(+)

diff --git a/src/modules/bluetooth/backend-native.c b/src/modules/bluetooth/backend-native.c
index d502cff78..b6991ae13 100644
--- a/src/modules/bluetooth/backend-native.c
+++ b/src/modules/bluetooth/backend-native.c
@@ -44,6 +44,9 @@
 #include "upower.h"
 #include "modemmanager.h"
 
+#define MAX_NUMBER_LENGTH 30
+#define STR_VALUE(x) STR(x)
+#define STR(x) #x
 #define RING_WAIT_TIME ((pa_usec_t) (3 * PA_USEC_PER_SEC))
 #define MANDATORY_CALL_INDICATORS \
         "(\"call\",(0-1))," \
@@ -935,6 +938,60 @@ static bool hfp_rfcomm_handle(int fd, pa_bluetooth_transport *t, const char *buf
             rfcomm_write_error(discovery->native_backend, fd, CMEE_OPERATION_NOT_ALLOWED);
         }
 
+	/* AT response will be reported through PA_BLUETOOTH_HOST_OPERATION_{SUCCEED, FAILED} hook */
+        return false;
+    } else if (strstr(buf, "ATD")) {
+        int k, j;
+        char number[MAX_NUMBER_LENGTH];
+        char number_filtered[MAX_NUMBER_LENGTH];
+
+        /* ATD$number; is only possible if ModemManager is availble */
+        if (!discovery->native_backend->modemmanager || !pa_modemmanager_has_modem(discovery->native_backend->modemmanager)) {
+            pa_log_debug("ModemManager backend unavailable, cannot create call with ATD$number;");
+            rfcomm_write_error(discovery->native_backend, fd, CMEE_NO_CONNECTION_TO_PHONE);
+            return false;
+        } else if (!pa_modemmanager_has_service(discovery->native_backend->modemmanager)) {
+            pa_log_debug("No network service, cannot create call with ATD$number;");
+            rfcomm_write_error(discovery->native_backend, fd, CMEE_NO_NETWORK_SERVICE);
+            return false;
+        }
+
+	/* Try to parse number from ATD command */
+        if (sscanf(buf, "ATD%" STR_VALUE(MAX_NUMBER_LENGTH) "s;", number) != 1) {
+            pa_log_debug("Cannot parse ATD$number: \"%s\"", buf);
+            rfcomm_write_error(discovery->native_backend, fd, CMEE_AG_FAILURE);
+            return false;
+        }
+
+        /* 
+         * Filter extracted number from invalid characters
+         * Allowed characters: 0-9, *, #, +, A-C
+         */
+        k=0;
+        memset(number_filtered, '\0', sizeof(char) * MAX_NUMBER_LENGTH);
+        for (j=0; j < MAX_NUMBER_LENGTH; j++) {
+            if ((number[j] >= '0' && number[j] <= '9')
+               || (number[j] == '*')
+               || (number[j] == '#')
+               || (number[j] == '+')
+               || (number[j] >= 'A' && number[j] <= 'C')) {
+                number_filtered[k] = number[j];
+                k++;
+            }
+            /* ATD commands ends with ';'. */
+            else if (number[j] == ';')
+                break;
+            /* Send error for invalid characters */
+            else {
+                pa_log_warn("Call creation canceled, invalid character found in dial string: %c", number[j]);
+                rfcomm_write_error(discovery->native_backend, fd, CMEE_INVALID_CHARACTERS_DIAL_STRING);
+                return false;
+            }
+        }
+
+        /* Create call for filtered number */
+        pa_modemmanager_start_call(discovery->native_backend->modemmanager, number_filtered); 
+
 	/* AT response will be reported through PA_BLUETOOTH_HOST_OPERATION_{SUCCEED, FAILED} hook */
         return false;
     } 
diff --git a/src/modules/bluetooth/bluez5-util.h b/src/modules/bluetooth/bluez5-util.h
index 4802cca69..ccbe6ba78 100644
--- a/src/modules/bluetooth/bluez5-util.h
+++ b/src/modules/bluetooth/bluez5-util.h
@@ -218,6 +218,7 @@ typedef enum pa_bluetooth_cmee {
     CMEE_OPERATION_NOT_ALLOWED = 3,
     CMEE_OPERATION_NOT_SUPPORTED = 4,
     CMEE_INVALID_CHARACTERS_TEXT_STRING = 25,
+    CMEE_INVALID_CHARACTERS_DIAL_STRING = 27,
     CMEE_NO_NETWORK_SERVICE = 30
 } pa_bluetooth_cmee_t;
 
-- 
2.35.1