Initial commit for em4x70 support.

Initially I only have an em4x70 variant used for car transponders.
Also known as the ID48.

client/src/cmdlfem4x70.c

@@ -0,0 +1,151 @@
+//-----------------------------------------------------------------------------
+// Copyright (C) 2020 sirloins
+//
+// 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.
+//-----------------------------------------------------------------------------
+// Low frequency EM4x70 commands
+//-----------------------------------------------------------------------------
+
+#include "cmdlfem4x70.h"
+#include <ctype.h>
+#include "cmdparser.h"    // command_t
+#include "fileutils.h"
+#include "comms.h"
+#include "commonutil.h"
+#include "em4x70.h"
+
+
+static int CmdHelp(const char *Cmd);
+
+
+static int usage_lf_em4x70_info(void) {
+    PrintAndLogEx(NORMAL, "Read all information of EM4x70. Tag must be on antenna.");
+    PrintAndLogEx(NORMAL, "");
+    PrintAndLogEx(NORMAL, "Usage:  lf em 4x70_info [h] [v] [p <pwd>]");
+    PrintAndLogEx(NORMAL, "Options:");
+    PrintAndLogEx(NORMAL, "       h         - this help");
+    PrintAndLogEx(NORMAL, "       p         - use even parity for commands");
+    PrintAndLogEx(NORMAL, "Examples:");
+    PrintAndLogEx(NORMAL, _YELLOW_("      lf em 4x70_info"));
+    PrintAndLogEx(NORMAL, _YELLOW_("      lf em 4x70_info p"));
+    PrintAndLogEx(NORMAL, "");
+    return PM3_SUCCESS;
+}
+
+static void print_info_result(uint8_t *data) {
+
+    PrintAndLogEx(NORMAL, "");
+    PrintAndLogEx(INFO, "--- " _CYAN_("Tag Information") " ---------------------------");
+    PrintAndLogEx(INFO, "-------------------------------------------------------------");
+
+    // data section
+    PrintAndLogEx(NORMAL, "");
+    PrintAndLogEx(INFO, _YELLOW_("EM4x70 data:"));
+    
+    for(int i=1; i <= 32; i+=2) {
+        PrintAndLogEx(NORMAL, "%02X %02X", data[32-i], data[32-i-1]);
+    }
+    PrintAndLogEx(NORMAL, "Tag ID: %02X %02X %02X %02X", data[7], data[6], data[5], data[4]);
+    PrintAndLogEx(NORMAL, "Lockbit 0: %d", (data[3] & 0x40) ? 1:0);
+    PrintAndLogEx(NORMAL, "Lockbit 1: %d", (data[3] & 0x80) ? 1:0);
+    PrintAndLogEx(NORMAL, "");
+
+}
+
+int em4x70_info(void) {
+    
+    em4x70_data_t edata = {
+        .parity = false // TODO: try both? or default to true
+    };
+
+    clearCommandBuffer();
+    SendCommandNG(CMD_LF_EM4X70_INFO, (uint8_t *)&edata, sizeof(edata));
+    
+    PacketResponseNG resp;
+    if (!WaitForResponseTimeout(CMD_LF_EM4X70_INFO, &resp, TIMEOUT)) {
+        PrintAndLogEx(WARNING, "(em4x70) timeout while waiting for reply.");
+        return PM3_ETIMEOUT;
+    }
+
+    if (resp.status) {
+        print_info_result(resp.data.asBytes);
+        return PM3_SUCCESS;
+    }
+
+    return PM3_ESOFT;
+}
+
+//quick test for EM4x70 tag
+bool detect_4x70_block(void) {
+
+    return em4x70_info() == PM3_SUCCESS;
+}
+
+int CmdEM4x70Info(const char *Cmd) {
+
+    // envoke reading of a EM4x70 tag which has to be on the antenna because
+    // decoding is done by the device (not on client side)
+
+    bool errors = false;
+    uint8_t cmdp = 0;
+
+    em4x70_data_t etd = {0};
+
+    while (param_getchar(Cmd, cmdp) != 0x00 && !errors) {
+        switch (tolower(param_getchar(Cmd, cmdp))) {
+
+            case 'h':
+                return usage_lf_em4x70_info();
+            
+            case 'p':
+                etd.parity = true;
+                cmdp +=1;
+                break;
+
+            default:
+                PrintAndLogEx(WARNING, "  Unknown parameter '%c'", param_getchar(Cmd, cmdp));
+                errors = true;
+                break;
+        }
+    }
+
+    // validation
+    if (errors)
+        return usage_lf_em4x70_info();
+
+    clearCommandBuffer();
+    SendCommandNG(CMD_LF_EM4X70_INFO, (uint8_t *)&etd, sizeof(etd));
+
+    PacketResponseNG resp;
+    if (!WaitForResponseTimeout(CMD_LF_EM4X70_INFO, &resp, TIMEOUT)) {
+        PrintAndLogEx(WARNING, "timeout while waiting for reply.");
+        return PM3_ETIMEOUT;
+    }
+
+    if (resp.status) {
+        print_info_result(resp.data.asBytes);
+        return PM3_SUCCESS;
+    }
+
+    PrintAndLogEx(FAILED, "reading tag " _RED_("failed"));
+    return PM3_ESOFT;
+}
+
+static command_t CommandTable[] = {
+    {"help",   CmdHelp,         AlwaysAvailable, "This help"},
+    {"info",   CmdEM4x70Info,   IfPm3EM4x70,     "tag information EM4x70"},
+    {NULL, NULL, NULL, NULL}
+};
+
+static int CmdHelp(const char *Cmd) {
+    (void)Cmd; // Cmd is not used so far
+    CmdsHelp(CommandTable);
+    return PM3_SUCCESS;
+}
+
+int CmdLFEM4X70(const char *Cmd) {
+    clearCommandBuffer();
+    return CmdsParse(CommandTable, Cmd);
+}