/* packet-lpd.c

 * Routines for LPR and LPRng packet disassembly

 * Gilbert Ramirez <gram@alumni.rice.edu>

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include <epan/packet.h>

void proto_register_lpd(void);

void proto_reg_handoff_lpd(void);

static dissector_handle_t lpd_handle;

#define TCP_PORT_PRINTER    515

static int proto_lpd;

static int hf_lpd_response;

static int hf_lpd_request;

static int hf_lpd_client_code;

static int hf_lpd_printer_option;

static int hf_lpd_response_code;

static int ett_lpd;

enum lpr_type { request, response, unknown };

static int find_printer_string(tvbuff_t *tvb, int offset);

/* This information comes from the LPRng HOWTO, which also describes

  RFC 1179. http://www.astart.com/lprng/LPRng-HOWTO.html */

static const value_string lpd_client_code[] = {

  { 1, "LPC: start print / jobcmd: abort" },

  { 2, "LPR: transfer a printer job / jobcmd: receive control file" },

  { 3, "LPQ: print short form of queue status / jobcmd: receive data file" },

  { 4, "LPQ: print long form of queue status" },

  { 5, "LPRM: remove jobs" },

  { 6, "LPRng lpc: do control operation" },

  { 7, "LPRng lpr: transfer a block format print job" },

  { 8, "LPRng lpc: secure command transfer" },

  { 9, "LPRng lpq: verbose status information" },

  { 0, NULL }

};

static const value_string lpd_server_code[] = {

  { 0, "Success: accepted, proceed" },

  { 1, "Queue not accepting jobs" },

  { 2, "Queue temporarily full, retry later" },

  { 3, "Bad job format, do not retry" },

  { 0, NULL }

};

static int

dissect_lpd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

  proto_tree  *lpd_tree;

  proto_item  *ti, *hidden_item;

  enum lpr_type lpr_packet_type;

  uint8_t   code;

  int   printer_len;

  col_set_str(pinfo->cinfo, COL_PROTOCOL, "LPD");

  col_clear(pinfo->cinfo, COL_INFO);

  /* rfc1179 states that all responses are 1 byte long */

  code = tvb_get_uint8(tvb, 0);

  if (tvb_reported_length(tvb) == 1) {

    lpr_packet_type = response;

  }

  else if (code <= 9) {

    lpr_packet_type = request;

  }

  else {

    lpr_packet_type = unknown;

  }

  if (lpr_packet_type == request && code !=0) {

    col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pinfo->pool, code, lpd_client_code, "Unknown client code: %u"));

  }

  else if (lpr_packet_type == response) {

    col_set_str(pinfo->cinfo, COL_INFO, "LPD response");

  }

  else {

    col_set_str(pinfo->cinfo, COL_INFO, "LPD continuation");

  }

    ti = proto_tree_add_item(tree, proto_lpd, tvb, 0, -1, ENC_NA);

    lpd_tree = proto_item_add_subtree(ti, ett_lpd);

    if (lpr_packet_type == response) {

      hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_response,

            tvb, 0, 0, true);

    } else {

      hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_request,

            tvb, 0, 0, true);

    }

    proto_item_set_hidden(hidden_item);

    if (lpr_packet_type == request) {

      printer_len = find_printer_string(tvb, 1);

      if (code <= 9 && printer_len != -1) {

        proto_tree_add_uint_format(lpd_tree, hf_lpd_client_code, tvb, 0, 1, code,

          "%s", val_to_str(pinfo->pool, code, lpd_client_code, "Unknown client code: %u"));

        proto_tree_add_item(lpd_tree, hf_lpd_printer_option, tvb, 1, printer_len, ENC_ASCII);

      }

      else {

        call_data_dissector(tvb, pinfo, lpd_tree);

      }

    }

    else if (lpr_packet_type == response) {

      if (code <= 3) {

        proto_tree_add_item(lpd_tree, hf_lpd_response_code, tvb, 0, 1, ENC_BIG_ENDIAN);

      }

      else {

        call_data_dissector(tvb, pinfo, lpd_tree);

      }

    }

    else {

      call_data_dissector(tvb, pinfo, lpd_tree);

    }

  return tvb_captured_length(tvb);

}

static int

find_printer_string(tvbuff_t *tvb, int offset)

{

  int i;

  /* try to find end of string, either '\n' or '\0' */

  i = tvb_find_uint8(tvb, offset, -1, '\0');

  if (i == -1)

    i = tvb_find_uint8(tvb, offset, -1, '\n');

  if (i == -1)

    return -1;

  return i - offset; /* length of string */

}

void

proto_register_lpd(void)

{

  static hf_register_info hf[] = {

    { &hf_lpd_response,

      { "Response",           "lpd.response",

        FT_BOOLEAN, BASE_NONE, NULL, 0x0,

        "true if LPD response", HFILL }},

    { &hf_lpd_request,

      { "Request",            "lpd.request",

        FT_BOOLEAN, BASE_NONE, NULL, 0x0,

        "true if LPD request", HFILL }},

    { &hf_lpd_client_code,

      { "Client code",            "lpd.client_code",

        FT_UINT8, BASE_DEC, VALS(lpd_client_code), 0x0,

        NULL, HFILL }},

    { &hf_lpd_printer_option,

      { "Printer/options",            "lpd.printer_option",

        FT_STRING, BASE_NONE, NULL, 0x0,

        NULL, HFILL }},

    { &hf_lpd_response_code,

      { "Response",            "lpd.response_code",

        FT_UINT8, BASE_DEC, VALS(lpd_server_code), 0x0,

        NULL, HFILL }},

  };

  static int *ett[] = {

    &ett_lpd,

  };

  proto_lpd = proto_register_protocol("Line Printer Daemon Protocol", "LPD", "lpd");

  lpd_handle = register_dissector("lpd", dissect_lpd, proto_lpd);

  proto_register_field_array(proto_lpd, hf, array_length(hf));

  proto_register_subtree_array(ett, array_length(ett));

}

void

proto_reg_handoff_lpd(void)

{

  dissector_add_uint_with_preference("tcp.port", TCP_PORT_PRINTER, lpd_handle);

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local variables:

 * c-basic-offset: 8

 * tab-width: 8

 * indent-tabs-mode: t

 * End:

 *

 * vi: set shiftwidth=8 tabstop=8 noexpandtab:

 * :indentSize=8:tabSize=8:noTabs=false:

 */