epan/dissectors/packet-lpd.c

   1 /* packet-lpd.c
   2  * Routines for LPR and LPRng packet disassembly
   3  * Gilbert Ramirez <gram@alumni.rice.edu>
   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 #include "config.h"
  13
  14 #include <epan/packet.h>
  15
  16 void proto_register_lpd(void);
  17 void proto_reg_handoff_lpd(void);
  18
  19 static dissector_handle_t lpd_handle;
  20
  21 #define TCP_PORT_PRINTER                515
  22
  23 static int proto_lpd;
  24 static int hf_lpd_response;
  25 static int hf_lpd_request;
  26 static int hf_lpd_client_code;
  27 static int hf_lpd_printer_option;
  28 static int hf_lpd_response_code;
  29
  30 static int ett_lpd;
  31
  32 enum lpr_type { request, response, unknown };
  33
  34 static int find_printer_string(tvbuff_t *tvb, int offset);
  35
  36 /* This information comes from the LPRng HOWTO, which also describes
  37         RFC 1179. http://www.astart.com/lprng/LPRng-HOWTO.html */
  38 static const value_string lpd_client_code[] = {
  39         { 1, "LPC: start print / jobcmd: abort" },
  40         { 2, "LPR: transfer a printer job / jobcmd: receive control file" },
  41         { 3, "LPQ: print short form of queue status / jobcmd: receive data file" },
  42         { 4, "LPQ: print long form of queue status" },
  43         { 5, "LPRM: remove jobs" },
  44         { 6, "LPRng lpc: do control operation" },
  45         { 7, "LPRng lpr: transfer a block format print job" },
  46         { 8, "LPRng lpc: secure command transfer" },
  47         { 9, "LPRng lpq: verbose status information" },
  48         { 0, NULL }
  49 };
  50 static const value_string lpd_server_code[] = {
  51         { 0, "Success: accepted, proceed" },
  52         { 1, "Queue not accepting jobs" },
  53         { 2, "Queue temporarily full, retry later" },
  54         { 3, "Bad job format, do not retry" },
  55         { 0, NULL }
  56 };
  57
  58 static int
  59 dissect_lpd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
  60 {
  61         proto_tree      *lpd_tree;
  62         proto_item      *ti, *hidden_item;
  63         enum lpr_type   lpr_packet_type;
  64         uint8_t         code;
  65         int             printer_len;
  66
  67         col_set_str(pinfo->cinfo, COL_PROTOCOL, "LPD");
  68         col_clear(pinfo->cinfo, COL_INFO);
  69
  70         /* rfc1179 states that all responses are 1 byte long */
  71         code = tvb_get_uint8(tvb, 0);
  72         if (tvb_reported_length(tvb) == 1) {
  73                 lpr_packet_type = response;
  74         }
  75         else if (code <= 9) {
  76                 lpr_packet_type = request;
  77         }
  78         else {
  79                 lpr_packet_type = unknown;
  80         }
  81
  82         if (lpr_packet_type == request && code !=0) {
  83                 col_add_str(pinfo->cinfo, COL_INFO, val_to_str(code, lpd_client_code, "Unknown client code: %u"));
  84         }
  85         else if (lpr_packet_type == response) {
  86                 col_set_str(pinfo->cinfo, COL_INFO, "LPD response");
  87         }
  88         else {
  89                 col_set_str(pinfo->cinfo, COL_INFO, "LPD continuation");
  90         }
  91
  92                 ti = proto_tree_add_item(tree, proto_lpd, tvb, 0, -1, ENC_NA);
  93                 lpd_tree = proto_item_add_subtree(ti, ett_lpd);
  94
  95                 if (lpr_packet_type == response) {
  96                   hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_response,
  97                                                 tvb, 0, 0, true);
  98                 } else {
  99                   hidden_item = proto_tree_add_boolean(lpd_tree, hf_lpd_request,
 100                                                 tvb, 0, 0, true);
 101                 }
 102                 proto_item_set_hidden(hidden_item);
 103
 104                 if (lpr_packet_type == request) {
 105                         printer_len = find_printer_string(tvb, 1);
 106
 107                         if (code <= 9 && printer_len != -1) {
 108                                 proto_tree_add_uint_format(lpd_tree, hf_lpd_client_code, tvb, 0, 1, code,
 109                                         "%s", val_to_str(code, lpd_client_code, "Unknown client code: %u"));
 110                                 proto_tree_add_item(lpd_tree, hf_lpd_printer_option, tvb, 1, printer_len, ENC_ASCII);
 111                         }
 112                         else {
 113                                 call_data_dissector(tvb, pinfo, lpd_tree);
 114                         }
 115                 }
 116                 else if (lpr_packet_type == response) {
 117                         if (code <= 3) {
 118                                 proto_tree_add_item(lpd_tree, hf_lpd_response_code, tvb, 0, 1, ENC_BIG_ENDIAN);
 119                         }
 120                         else {
 121                                 call_data_dissector(tvb, pinfo, lpd_tree);
 122                         }
 123                 }
 124                 else {
 125                         call_data_dissector(tvb, pinfo, lpd_tree);
 126                 }
 127
 128         return tvb_captured_length(tvb);
 129 }
 130
 131
 132 static int
 133 find_printer_string(tvbuff_t *tvb, int offset)
 134 {
 135         int     i;
 136
 137         /* try to find end of string, either '\n' or '\0' */
 138         i = tvb_find_uint8(tvb, offset, -1, '\0');
 139         if (i == -1)
 140                 i = tvb_find_uint8(tvb, offset, -1, '\n');
 141         if (i == -1)
 142                 return -1;
 143         return i - offset;      /* length of string */
 144 }
 145
 146
 147 void
 148 proto_register_lpd(void)
 149 {
 150         static hf_register_info hf[] = {
 151                 { &hf_lpd_response,
 152                   { "Response",           "lpd.response",
 153                     FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 154                     "true if LPD response", HFILL }},
 155
 156                 { &hf_lpd_request,
 157                   { "Request",            "lpd.request",
 158                     FT_BOOLEAN, BASE_NONE, NULL, 0x0,
 159                     "true if LPD request", HFILL }},
 160
 161                 { &hf_lpd_client_code,
 162                   { "Client code",            "lpd.client_code",
 163                     FT_UINT8, BASE_DEC, VALS(lpd_client_code), 0x0,
 164                     NULL, HFILL }},
 165
 166                 { &hf_lpd_printer_option,
 167                   { "Printer/options",            "lpd.printer_option",
 168                     FT_STRING, BASE_NONE, NULL, 0x0,
 169                     NULL, HFILL }},
 170
 171                 { &hf_lpd_response_code,
 172                   { "Response",            "lpd.response_code",
 173                     FT_UINT8, BASE_DEC, VALS(lpd_server_code), 0x0,
 174                     NULL, HFILL }},
 175         };
 176         static int *ett[] = {
 177                 &ett_lpd,
 178         };
 179
 180         proto_lpd = proto_register_protocol("Line Printer Daemon Protocol", "LPD", "lpd");
 181         lpd_handle = register_dissector("lpd", dissect_lpd, proto_lpd);
 182         proto_register_field_array(proto_lpd, hf, array_length(hf));
 183         proto_register_subtree_array(ett, array_length(ett));
 184 }
 185
 186 void
 187 proto_reg_handoff_lpd(void)
 188 {
 189         dissector_add_uint_with_preference("tcp.port", TCP_PORT_PRINTER, lpd_handle);
 190 }
 191
 192 /*
 193  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 194  *
 195  * Local variables:
 196  * c-basic-offset: 8
 197  * tab-width: 8
 198  * indent-tabs-mode: t
 199  * End:
 200  *
 201  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 202  * :indentSize=8:tabSize=8:noTabs=false:
 203  */