Capture Razer Orbweaver HID traffic

libhidapicap.c

/*
 * License: WTFPL
 * Markus Törnqvist <mjt@nysv.org>
 *
 * Influenced heavily by http://www.linuxquestions.org/questions/programming-9/read-from-a-usb-barcode-scanner-that-simulates-a-keyboard-495358/
 * and the hidapi README example
 */

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "hidapi/hidapi.h"

// Orbweaver
#define VENDOR_ID  0x1532
#define PRODUCT_ID 0x0113

// Kinesis
//#define VENDOR_ID  0x05f3
//#define PRODUCT_ID 0x0007

#define TIMEOUT_MS 30
#define PACKET_LEN 3

#define L_CTRL  1
#define L_SHIFT 2
#define L_ALT   4

#define CLEAN_AND_RETURN(x) {hid_free_enumeration(x); return NULL;}

// from /usr/src/linux/drivers/usb/input/usbkbd.c
static char usb_kbd_scancode[256] = {
     0,  0,  0,  0, 30, 48, 46, 32, 18, 33, 34, 35, 23, 36, 37, 38,
    50, 49, 24, 25, 16, 19, 31, 20, 22, 47, 17, 45, 21, 44,  2,  3,
     4,  5,  6,  7,  8,  9, 10, 11, 28,  1, 14, 15, 57, 12, 13, 26,
    27, 43, 43, 39, 40, 41, 51, 52, 53, 58, 59, 60, 61, 62, 63, 64,
    65, 66, 67, 68, 87, 88, 99, 70,119,110,102,104,111,107,109,106,
   105,108,103, 69, 98, 55, 74, 78, 96, 79, 80, 81, 75, 76, 77, 71,
    72, 73, 82, 83, 86,127,116,117,183,184,185,186,187,188,189,190,
   191,192,193,194,134,138,130,132,128,129,131,137,133,135,136,113,
   115,114,  0,  0,  0,121,  0, 89, 93,124, 92, 94, 95,  0,  0,  0,
   122,123, 90, 91, 85,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    29, 42, 56,125, 97, 54,100,126,164,166,165,163,161,115,114,113,
   150,158,159,128,136,177,178,176,142,152,173,140
};

char scancodelist(int scancode) {
  char ret = NULL;

  switch (usb_kbd_scancode[scancode]) {
      case 0x02: ret ='1'; break;
      case 0x03: ret ='2'; break;
      case 0x04: ret ='3'; break;
      case 0x05: ret ='4'; break;
      case 0x06: ret ='5'; break;
      case 0x07: ret ='6'; break;
      case 0x08: ret ='7'; break;
      case 0x09: ret ='8'; break;
      case 0x0a: ret ='9'; break;
      case 0x0b: ret ='0'; break;
      case 0x0f: ret ='T'; break; // TAB
      case 0x1e: ret ='a'; break;
      case 0x30: ret ='b'; break;
      case 0x2e: ret ='c'; break;
      case 0x20: ret ='d'; break;
      case 0x12: ret ='e'; break;
      case 0x21: ret ='f'; break;
      case 0x22: ret ='g'; break;
      case 0x23: ret ='h'; break;
      case 0x17: ret ='i'; break;
      case 0x24: ret ='j'; break;
      case 0x25: ret ='k'; break;
      case 0x26: ret ='l'; break;
      case 0x29: ret ='X'; break; // backtick, to remap
      case 0x32: ret ='m'; break;
      case 0x31: ret ='n'; break;
      case 0x3a: ret ='C'; break; // capslock, could be l-ctrl
      case 0x18: ret ='o'; break;
      case 0x19: ret ='p'; break;
      case 0x10: ret ='q'; break;
      case 0x13: ret ='r'; break;
      case 0x1f: ret ='s'; break;
      case 0x14: ret ='t'; break;
      case 0x16: ret ='u'; break;
      case 0x2f: ret ='v'; break;
      case 0x11: ret ='w'; break;
      case 0x2d: ret ='x'; break;
      case 0x15: ret ='y'; break;
      case 0x2c: ret ='z'; break;
      case 0x0c: ret ='-'; break;
      default: break;
  }
  
  return ret;
}

hid_device* get_hid() {
    hid_device *hid = NULL;

    struct hid_device_info *devs;
    struct hid_device_info *cur_dev = NULL;

    devs = hid_enumerate(0x0, 0x0);

    cur_dev = devs;
    do {
        if (cur_dev->vendor_id == VENDOR_ID && cur_dev->product_id == PRODUCT_ID) {
            printf("Found!\n");
            printf("0x%x, 0x%x, %ls\n", cur_dev->vendor_id, cur_dev->product_id, cur_dev->serial_number);
            break;
        }
    } while ((cur_dev = cur_dev->next));

    if (!cur_dev) {
        printf("Warning, returning NULL device\n");
        CLEAN_AND_RETURN(devs);
    }

    hid = hid_open(cur_dev->vendor_id, cur_dev->product_id, cur_dev->serial_number);
    if (hid == NULL) {
        perror("Open failed :( errno");
        CLEAN_AND_RETURN(devs);
    }

    hid_free_enumeration(devs);

    return hid;
}

char* read_hid(hid_device *hid) {
    int read_retval;
    unsigned char data[PACKET_LEN];
    int modifier;
    int scancode;
    int code;

    memset(data, 0, PACKET_LEN);

    while (1) {
        read_retval = hid_read_timeout(hid, data, PACKET_LEN, TIMEOUT_MS);
        modifier = (int) data[0]; // No idea what data[1] is :/
        scancode = (int) data[2];

        if (modifier) {
            // Do not allow slapping down two of these, only one bit set
            if ((modifier & (modifier - 1))) continue;

            /* FIXME: this does not make sense
            if (modifier & L_CTRL) {
                scancode = 29; // Index 29 resolves to ,
            } else if (modifier & L_SHIFT) {
                scancode = 6;  // Index 6 resolves to ,
            } else if (modifier & L_ALT) {
                scancode = 27; // Index 27 resolves to -
            }
            */
        }

        /* printf("read_retval %d\n", read_retval); */
        /* printf("data |%s|\n", data); */
        /* printf("m data[0] |%d|\n", modifier); */
        /* printf("  data[1] |%d|\n", (int) data[1]); */
        /* printf("s data[2] |%d|\n", scancode); */
        code = scancodelist(scancode);
        if (code) {
            printf("code %c\n", code);
            if (code == 'q') break;
        }

        if (read_retval == 0) {
            /* printf("Skipped a read?"); */
        } else if (read_retval == -1) {
            perror("hid_read returned -1");
            break;
        }
    }
    return NULL;
}

int main(int argc, char *argv[]) {
    hid_device *hid = get_hid();
    if (!hid) {
        printf("No matching device found\n");
        return ENODEV;
    }

    read_hid(hid);

    hid_close(hid);

    return 0;
}