Several changes in the initial connection, see details:

* TestProxmark uses pingng
* New command CMD_CAPABILITIES to transmit capabilities from pm3 to host
* Use TestProxmark to retrieve capabilities with that new command
* CloseProxmark if TestProxmark fails
* Hide baudrate for USB and retrieve real baudrate from pm3 for BT

armsrc/appmain.c

@@ -429,6 +429,16 @@ void SendStatus(void) {
     reply_old(CMD_ACK, 1, 0, 0, 0, 0);
 }
 
+void SendCapabilities(void) {
+    capabilities_t capabilities;
+    capabilities.via_fpc = reply_via_fpc;
+    if (reply_via_fpc)
+        capabilities.baudrate = USART_BAUD_RATE;
+    else
+        capabilities.baudrate = 0; // no real baudrate for USB-CDC
+    reply_ng(CMD_CAPABILITIES, PM3_SUCCESS, (uint8_t *)&capabilities, sizeof(capabilities));
+}
+
 // Show some leds in a pattern to identify StandAlone mod is running
 void StandAloneMode(void) {
 
@@ -1439,6 +1449,8 @@ static void PacketReceived(PacketCommandNG *packet) {
         case CMD_STATUS:
             SendStatus();
             break;
+        case CMD_CAPABILITIES:
+            SendCapabilities();
         case CMD_PING:
             if (packet->ng) {
                 reply_ng(CMD_PING, PM3_SUCCESS, packet->data.asBytes, packet->length);

client/comms.c

@@ -20,6 +20,7 @@ static char *serial_port_name = NULL;
 static bool offline;
 
 communication_arg_t conn;
+capabilities_t pm3_capabilities;
 
 static pthread_t USB_communication_thread;
 //static pthread_t FPC_communication_thread;
@@ -567,22 +568,40 @@ bool OpenProxmark(void *port, bool wait_for_port, int timeout, bool flash_mode,
 int TestProxmark(void) {
     clearCommandBuffer();
     PacketResponseNG resp;
-    SendCommandOLD(CMD_PING, 0, 0, 0, NULL, 0);
+    uint16_t len = 32;
+    uint8_t data[len];
+    for (uint16_t i = 0; i < len; i++)
+        data[i] = i & 0xFF;
+    SendCommandNG(CMD_PING, data, len);
 #ifdef USART_SLOW_LINK
     // 10s timeout for slow FPC, e.g. over BT
     // as this is the very first command sent to the pm3
     // that initiates the BT connection
-    if (WaitForResponseTimeout(CMD_ACK, &resp, 10000)) {
+    if (WaitForResponseTimeoutW(CMD_PING, &resp, 10000, false)) {
 #else
-    if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) {
+    if (WaitForResponseTimeoutW(CMD_PING, &resp, 1000, false)) {
 #endif
-        conn.send_via_fpc = resp.oldarg[0] == 1;
-        PrintAndLogEx(INFO, "Communicating with PM3 over %s.", conn.send_via_fpc ? _YELLOW_("FPC") : _YELLOW_("USB-CDC"));
-        if (conn.send_via_fpc)
-            PrintAndLogEx(INFO, "UART Serial baudrate: " _YELLOW_("%u") "\n", conn.uart_speed);
-        return 1;
+
+        bool error = false;
+        if (len)
+            error = memcmp(data, resp.data.asBytes, len) != 0;
+        if (error)
+            return PM3_EIO;
+
+        SendCommandNG(CMD_CAPABILITIES, NULL, 0);
+        if (WaitForResponseTimeoutW(CMD_PING, &resp, 1000, false)) {
+            memcpy(&pm3_capabilities, resp.data.asBytes, resp.length);
+            conn.send_via_fpc = pm3_capabilities.via_fpc;
+            conn.uart_speed = pm3_capabilities.baudrate;
+            PrintAndLogEx(INFO, "Communicating with PM3 over %s", conn.send_via_fpc ? _YELLOW_("FPC UART") : _YELLOW_("USB-CDC"));
+            if (conn.send_via_fpc)
+                PrintAndLogEx(INFO, "UART Serial baudrate: " _YELLOW_("%u") "\n", conn.uart_speed);
+            return PM3_SUCCESS;
+        } else {
+            return PM3_ETIMEOUT;
+        }
     } else {
-        return 0;
+        return PM3_ETIMEOUT;
     }
 }
 

client/comms.h

@@ -47,7 +47,7 @@ typedef struct {
     bool send_with_crc_on_fpc;
     // "Session" flag, to tell via which interface next msgs are sent: USB or FPC USART
     bool send_via_fpc;
-    // To memorise baudrate, we don't want to call get_speed systematically
+    // To memorise baudrate
     uint32_t uart_speed;
 } communication_arg_t;
 

client/proxmark3.c

@@ -468,8 +468,11 @@ int main(int argc, char *argv[]) {
     if (port != NULL)
         pm3_present = OpenProxmark(port, waitCOMPort, 20, false, speed);
 
-    if (pm3_present && (TestProxmark() == 0))
+    if (pm3_present && (TestProxmark() != PM3_SUCCESS)) {
+        PrintAndLogEx(ERR, _RED_("ERROR:") "cannot communicate with the Proxmark\n");
+        CloseProxmark();
         pm3_present = false;
+    }
     if (!pm3_present)
         PrintAndLogEx(INFO, "Running in " _YELLOW_("OFFLINE") "mode. Check \"%s -h\" if it's not what you want.\n", exec_name);
 

include/usb_cmd.h

@@ -136,6 +136,14 @@ typedef struct {
     uint16_t read_gap;
 } t55xx_config;
 
+// TODO add more fields to report all hw & sw capabilities of pm3
+typedef struct {
+    uint32_t baudrate;
+    bool via_fpc;
+} PACKED capabilities_t;
+
+extern capabilities_t pm3_capabilities;
+
 // For the bootloader
 #define CMD_DEVICE_INFO                                                   0x0000
 #define CMD_SETUP_WRITE                                                   0x0001
@@ -156,12 +164,9 @@ typedef struct {
 #define CMD_VERSION                                                       0x0107
 #define CMD_STATUS                                                        0x0108
 #define CMD_PING                                                          0x0109
-
 #define CMD_DOWNLOAD_EML_BIGBUF                                           0x0110
 #define CMD_DOWNLOADED_EML_BIGBUF                                         0x0111
-
-
-
+#define CMD_CAPABILITIES                                                  0x0112
 
 // RDV40, Flash memory operations
 #define CMD_FLASHMEM_READ                                                 0x0120