epan/dissectors/packet-usb-printer.c

   1 /* packet-usb-printer.c
   2  *
   3  * Copyright 2020, Martin Kaiser <martin@kaiser.cx>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 /*
  13  * References:
  14  *
  15  * USB printer class specification
  16  * https://www.usb.org/sites/default/files/usbprint11a021811.pdf
  17  *
  18  * IEEE 1284 (parallel peripheral interface for personal computers)
  19  * http://kazus.ru/nuke/modules/Downloads/pub/148/0/IEEE%201284-2000.pdf
  20  */
  21
  22 #include "config.h"
  23 #include <epan/packet.h>
  24 #include <epan/proto.h>
  25 #include "packet-usb.h"
  26 #include <epan/value_string.h>
  27
  28 static dissector_handle_t usb_printer_ctl_handle;
  29
  30 static int proto_usb_printer;
  31
  32 static int hf_usb_printer_req;
  33 static int hf_usb_printer_cfg_idx;
  34 static int hf_usb_printer_intf;
  35 static int hf_usb_printer_alt_set;
  36 static int hf_usb_printer_max_len;
  37 static int hf_usb_printer_dev_id_len;
  38 static int hf_usb_printer_dev_id;
  39
  40 static int ett_usb_printer;
  41
  42 void proto_register_usb_printer(void);
  43 void proto_reg_handoff_usb_printer(void);
  44
  45 #define REQ_GET_DEV_ID    0
  46 #define REQ_GET_PORT_STAT 1
  47 #define REQ_GET_SOFT_RST  2
  48
  49 static const value_string usb_printer_req[] = {
  50     { REQ_GET_DEV_ID,    "GET_DEVICE_ID" },
  51     { REQ_GET_PORT_STAT, "GET_PORT_STATUS" },
  52     { REQ_GET_SOFT_RST,  "SOFT_RESET" },
  53     { 0, NULL }
  54 };
  55
  56 static int dissect_usb_printer_ctl(
  57         tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
  58 {
  59     bool is_request = (pinfo->srcport == NO_ENDPOINT);
  60     urb_info_t *urb = (urb_info_t *)data;
  61     usb_trans_info_t *usb_trans_info;
  62     int offset = 0;
  63     uint8_t bReq;
  64     uint32_t dev_id_len;
  65
  66     if (!urb)
  67         return 0;
  68
  69     usb_trans_info = urb->usb_trans_info;
  70     if (!usb_trans_info)
  71         return 0;
  72
  73     col_set_str(pinfo->cinfo, COL_PROTOCOL, "USBPRINTER");
  74     col_set_str(pinfo->cinfo, COL_INFO,
  75             val_to_str_const(usb_trans_info->setup.request,
  76                 usb_printer_req, "Invalid"));
  77
  78     if (is_request) {
  79         col_append_str(pinfo->cinfo, COL_INFO, " request");
  80
  81         bReq = tvb_get_uint8(tvb, offset);
  82         proto_tree_add_item(tree, hf_usb_printer_req,
  83                 tvb, offset, 1, ENC_LITTLE_ENDIAN);
  84         offset++;
  85
  86         if (bReq == REQ_GET_DEV_ID) {
  87             /* Generally, fields in USB messages are little endian. */
  88             proto_tree_add_item(tree, hf_usb_printer_cfg_idx,
  89                     tvb, offset, 2, ENC_LITTLE_ENDIAN);
  90             offset += 2;
  91             proto_tree_add_item(tree, hf_usb_printer_intf,
  92                     tvb, offset, 2, ENC_LITTLE_ENDIAN);
  93             proto_tree_add_item(tree, hf_usb_printer_alt_set,
  94                     tvb, offset, 2, ENC_LITTLE_ENDIAN);
  95             offset += 2;
  96             proto_tree_add_item(tree, hf_usb_printer_max_len,
  97                     tvb, offset, 2, ENC_LITTLE_ENDIAN);
  98             offset += 2;
  99         }
 100     }
 101     else {
 102         col_append_str(pinfo->cinfo, COL_INFO, " response");
 103
 104         if (usb_trans_info->setup.request == REQ_GET_DEV_ID) {
 105             /*
 106              * A printer's Device ID is defined in IEEE 1284, section 7.6.
 107              * It starts with a 16-bit length field in big endian encoding.
 108              * The length field includes the two bytes for itself. Therefore,
 109              * we can't use an FT_UINT_STRING for the entire Device ID.
 110              * The actual Device ID string consists of ASCII characters.
 111              */
 112             proto_tree_add_item_ret_uint(tree, hf_usb_printer_dev_id_len,
 113                     tvb, offset, 2, ENC_BIG_ENDIAN, &dev_id_len);
 114             offset += 2;
 115             if (dev_id_len > 2) {
 116                 proto_tree_add_item(tree, hf_usb_printer_dev_id,
 117                         tvb, offset, dev_id_len-2, ENC_ASCII);
 118                 offset += dev_id_len-2;
 119             }
 120             /* XXX - expert info for invalid dev_id_len */
 121         }
 122     }
 123
 124     return offset;
 125 }
 126
 127 void proto_register_usb_printer(void)
 128 {
 129     static hf_register_info hf[] = {
 130         { &hf_usb_printer_req,
 131             { "bRequest", "usbprinter.bRequest", FT_UINT8, BASE_HEX,
 132                 VALS(usb_printer_req), 0x0, NULL, HFILL }
 133         },
 134         { &hf_usb_printer_cfg_idx,
 135             { "Config index", "usbprinter.config_index", FT_UINT16, BASE_HEX,
 136                 NULL, 0x0, NULL, HFILL }
 137         },
 138         { &hf_usb_printer_intf,
 139             { "Interface", "usbprinter.interface", FT_UINT16, BASE_HEX,
 140                 NULL, 0xFF00, NULL, HFILL }
 141         },
 142         { &hf_usb_printer_alt_set,
 143             { "Alternate setting", "usbprinter.alt_set", FT_UINT16, BASE_HEX,
 144                 NULL, 0x00FF, NULL, HFILL }
 145         },
 146         { &hf_usb_printer_max_len,
 147             { "Maximum length", "usbprinter.max_len", FT_UINT16, BASE_HEX,
 148                 NULL, 0, NULL, HFILL }
 149         },
 150         { &hf_usb_printer_dev_id_len,
 151             { "Device ID length", "usbprinter.device_id_len", FT_UINT16,
 152                 BASE_HEX, NULL, 0, NULL, HFILL }
 153         },
 154         { &hf_usb_printer_dev_id,
 155             { "Device ID", "usbprinter.device_id", FT_STRING, BASE_NONE,
 156                 NULL, 0, NULL, HFILL }
 157         }
 158     };
 159
 160     static int *ett[] = {
 161         &ett_usb_printer
 162     };
 163
 164     proto_usb_printer = proto_register_protocol("USB Printer", "USBPRINTER", "usbprinter");
 165     proto_register_field_array(proto_usb_printer, hf, array_length(hf));
 166     proto_register_subtree_array(ett, array_length(ett));
 167     usb_printer_ctl_handle = register_dissector("usbprinter",  dissect_usb_printer_ctl, proto_usb_printer);
 168 }
 169
 170 void
 171 proto_reg_handoff_usb_printer(void)
 172 {
 173     dissector_add_uint("usb.control", IF_CLASS_PRINTER, usb_printer_ctl_handle);
 174 }
 175
 176 /*
 177 * Editor modelines - https://www.wireshark.org/tools/modelines.html
 178 *
 179 * Local variables:
 180 * c-basic-offset: 4
 181 * tab-width: 8
 182 * indent-tabs-mode: nil
 183 * End:
 184 *
 185 * ex: set shiftwidth=4 tabstop=8 expandtab:
 186 * :indentSize=4:tabSize=8:noTabs=true:
 187 */