]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - client/comms.c
Comms refactor (prerequisite of libproxmark work) (#371)
[proxmark3-svn] / client / comms.c
diff --git a/client/comms.c b/client/comms.c
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+//-----------------------------------------------------------------------------
+// Copyright (C) 2009 Michael Gernoth <michael at gernoth.net>
+// Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Code for communicating with the proxmark3 hardware.
+//-----------------------------------------------------------------------------
+
+#include <pthread.h>
+
+#include "comms.h"
+#include "uart.h"
+#include "ui.h"
+#include "common.h"
+#include "data.h"
+#include "util_posix.h"
+
+// Declare globals.
+
+// Serial port that we are communicating with the PM3 on.
+static serial_port* port;
+
+// If TRUE, then there is no active connection to the PM3, and we will drop commands sent.
+static bool offline;
+
+// Transmit buffer.
+// TODO: Use locks and execute this on the main thread, rather than the receiver
+// thread.  Running on the main thread means we need to be careful in the
+// flasher, as it means SendCommand is no longer async, and can't be used as a
+// buffer for a pending command when the connection is re-established.
+static UsbCommand txcmd;
+static bool txcmd_pending;
+
+// Used by UsbReceiveCommand as a ring buffer for messages that are yet to be
+// processed by a command handler (WaitForResponse{,Timeout})
+static UsbCommand cmdBuffer[CMD_BUFFER_SIZE];
+
+// Points to the next empty position to write to
+static int cmd_head = 0;
+
+// Points to the position of the last unread command
+static int cmd_tail = 0;
+
+// to lock cmdBuffer operations from different threads
+static pthread_mutex_t cmdBufferMutex = PTHREAD_MUTEX_INITIALIZER;
+
+// These wrappers are required because it is not possible to access a static
+// global variable outside of the context of a single file.
+
+void SetSerialPort(serial_port* new_port) {
+       port = new_port;
+}
+
+serial_port* GetSerialPort() {
+       return port;
+}
+
+void SetOffline(bool new_offline) {
+       offline = new_offline;
+}
+
+bool IsOffline() {
+       return offline;
+}
+
+void SendCommand(UsbCommand *c) {
+       #ifdef COMMS_DEBUG
+       printf("Sending %04x cmd\n", c->cmd);
+       #endif
+
+       if (offline) {
+      PrintAndLog("Sending bytes to proxmark failed - offline");
+      return;
+    }
+  /**
+       The while-loop below causes hangups at times, when the pm3 unit is unresponsive
+       or disconnected. The main console thread is alive, but comm thread just spins here.
+       Not good.../holiman
+       **/
+       while(txcmd_pending);
+       txcmd = *c;
+       txcmd_pending = true;
+}
+
+/**
+ * @brief This method should be called when sending a new command to the pm3. In case any old
+ *  responses from previous commands are stored in the buffer, a call to this method should clear them.
+ *  A better method could have been to have explicit command-ACKS, so we can know which ACK goes to which
+ *  operation. Right now we'll just have to live with this.
+ */
+void clearCommandBuffer()
+{
+       //This is a very simple operation
+       pthread_mutex_lock(&cmdBufferMutex);
+       cmd_tail = cmd_head;
+       pthread_mutex_unlock(&cmdBufferMutex);
+}
+
+/**
+ * @brief storeCommand stores a USB command in a circular buffer
+ * @param UC
+ */
+void storeCommand(UsbCommand *command)
+{
+       pthread_mutex_lock(&cmdBufferMutex);
+       if( (cmd_head+1) % CMD_BUFFER_SIZE == cmd_tail)
+       {
+               // If these two are equal, we're about to overwrite in the
+               // circular buffer.
+               PrintAndLog("WARNING: Command buffer about to overwrite command! This needs to be fixed!");
+       }
+
+       // Store the command at the 'head' location
+       UsbCommand* destination = &cmdBuffer[cmd_head];
+       memcpy(destination, command, sizeof(UsbCommand));
+
+       cmd_head = (cmd_head +1) % CMD_BUFFER_SIZE; //increment head and wrap
+       pthread_mutex_unlock(&cmdBufferMutex);
+}
+
+
+/**
+ * @brief getCommand gets a command from an internal circular buffer.
+ * @param response location to write command
+ * @return 1 if response was returned, 0 if nothing has been received
+ */
+int getCommand(UsbCommand* response)
+{
+       pthread_mutex_lock(&cmdBufferMutex);
+       //If head == tail, there's nothing to read, or if we just got initialized
+       if (cmd_head == cmd_tail){
+               pthread_mutex_unlock(&cmdBufferMutex);
+               return 0;
+       }
+
+       //Pick out the next unread command
+       UsbCommand* last_unread = &cmdBuffer[cmd_tail];
+       memcpy(response, last_unread, sizeof(UsbCommand));
+       //Increment tail - this is a circular buffer, so modulo buffer size
+       cmd_tail = (cmd_tail + 1) % CMD_BUFFER_SIZE;
+
+       pthread_mutex_unlock(&cmdBufferMutex);
+       return 1;
+}
+
+//-----------------------------------------------------------------------------
+// Entry point into our code: called whenever we received a packet over USB
+// that we weren't necessarily expecting, for example a debug print.
+//-----------------------------------------------------------------------------
+void UsbCommandReceived(UsbCommand *UC)
+{
+       switch(UC->cmd) {
+
+       // First check if we are handling a debug message
+       case CMD_DEBUG_PRINT_STRING: {
+               char s[USB_CMD_DATA_SIZE+1];
+               memset(s, 0x00, sizeof(s));
+               size_t len = MIN(UC->arg[0],USB_CMD_DATA_SIZE);
+               memcpy(s,UC->d.asBytes,len);
+               PrintAndLog("#db# %s", s);
+               return;
+       }
+
+       case CMD_DEBUG_PRINT_INTEGERS: {
+               PrintAndLog("#db# %08x, %08x, %08x       \r\n", UC->arg[0], UC->arg[1], UC->arg[2]);
+               return;
+       }
+
+       case CMD_DOWNLOADED_RAW_ADC_SAMPLES_125K: {
+               // FIXME: This does unsanitised copies into memory when we don't know
+               // the size of the buffer.
+               if (sample_buf) {
+                       memcpy(sample_buf+(UC->arg[0]),UC->d.asBytes,UC->arg[1]);
+               }
+               return;
+       }
+
+       default: {
+               storeCommand(UC);
+               return;
+       }
+       }
+}
+
+// Gets a single command from a proxmark3 device. This should never be used
+// with the full client.
+//
+// @param conn A receiver_arg structure.
+// @param command A buffer to store the received command.
+bool ReceiveCommand(receiver_arg* conn, UsbCommand* command) {
+       // Local recieve buffer
+       size_t rxlen;
+       byte_t rx[sizeof(UsbCommand)];
+       byte_t* prx = rx;
+
+       while (conn->run) {
+               rxlen = 0;
+               if (uart_receive(port, prx, sizeof(UsbCommand) - (prx-rx), &rxlen) && rxlen) {
+                       prx += rxlen;
+                       if (prx-rx < sizeof(UsbCommand)) {
+                               // Keep reading until we have a completed response.
+                               continue;
+                       }
+
+                       // We have a completed response.
+                       memcpy(command, rx, sizeof(UsbCommand));
+                       return true;
+               }
+
+               if (prx == rx) {
+                       // We got no complete command while waiting, give up control
+                       return false;
+               }
+       }
+
+       // did not get a complete command before being cancelled.
+       return false;
+}
+
+// Worker thread for processing incoming events from the PM3
+void *uart_receiver(void *targ) {
+       receiver_arg *conn = (receiver_arg*)targ;
+       UsbCommand rx;
+
+       while (conn->run) {
+               #ifdef COMMS_DEBUG
+               printf("uart_receiver: get lock\n");
+               #endif
+               // Lock up receives, in case they try to take it away from us.
+               pthread_mutex_lock(&conn->recv_lock);
+               #ifdef COMMS_DEBUG
+               printf("uart_receiver: lock acquired\n");
+               #endif
+
+               if (port == NULL) {
+                       #ifdef COMMS_DEBUG
+                       printf("uart_receiver: port disappeared\n");
+                       #endif
+                       // Our port disappeared, stall. This code path matters for the flasher,
+                       // where it is fiddling with the serial port under us.
+                       pthread_mutex_unlock(&conn->recv_lock);
+                       msleep(10);
+                       continue;
+               }
+
+               bool got_command = ReceiveCommand(conn, &rx);
+               #ifdef COMMS_DEBUG
+               printf("uart_receiver: got command\n");
+               #endif
+               pthread_mutex_unlock(&conn->recv_lock);
+
+               if (got_command) {
+                       UsbCommandReceived(&rx);
+               }
+
+               // We aren't normally trying to transmit in the flasher when the port would
+               // be reset, so we can just keep going at this point.
+               if (txcmd_pending) {
+                       if (!uart_send(port, (byte_t*) &txcmd, sizeof(UsbCommand))) {
+                               PrintAndLog("Sending bytes to proxmark failed");
+                       }
+                       txcmd_pending = false;
+               }
+       }
+
+       pthread_exit(NULL);
+       return NULL;
+}
+
+/**
+ * Waits for a certain response type. This method waits for a maximum of
+ * ms_timeout milliseconds for a specified response command.
+ *@brief WaitForResponseTimeout
+ * @param cmd command to wait for, or CMD_ANY to take any command.
+ * @param response struct to copy received command into.
+ * @param ms_timeout
+ * @param show_warning
+ * @return true if command was returned, otherwise false
+ */
+bool WaitForResponseTimeoutW(uint64_t cmd, UsbCommand* response, size_t ms_timeout, bool show_warning) {
+       UsbCommand resp;
+
+       #ifdef COMMS_DEBUG
+       printf("Waiting for %04x cmd\n", cmd);
+       #endif
+       
+       if (response == NULL) {
+               response = &resp;
+       }
+
+       uint64_t start_time = msclock();
+
+       // Wait until the command is received
+       for (;;) {
+               while(getCommand(response)) {
+                       if (cmd == CMD_ANY || response->cmd == cmd) {
+                               return true;
+                       }
+               }
+               
+               if (msclock() - start_time > ms_timeout) {
+                       // We timed out.
+                       break;
+               }
+               
+               if (msclock() - start_time > 2000 && show_warning) {
+                       // 2 seconds elapsed (but this doesn't mean the timeout was exceeded)
+                       PrintAndLog("Waiting for a response from the proxmark...");
+                       PrintAndLog("Don't forget to cancel its operation first by pressing on the button");
+                       break;
+               }
+       }
+       return false;
+}
+
+bool WaitForResponseTimeout(uint64_t cmd, UsbCommand* response, size_t ms_timeout) {
+       return WaitForResponseTimeoutW(cmd, response, ms_timeout, true);
+}
+
+bool WaitForResponse(uint64_t cmd, UsbCommand* response) {
+       return WaitForResponseTimeout(cmd, response, -1);
+}
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