/* packet-tftp.c * Routines for tftp packet dissection * * Richard Sharpe * Craig Newell * RFC2347 TFTP Option Extension * * $Id: packet-tftp.c,v 1.24 2001/02/09 06:08:11 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * Copied from packet-bootp.c * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #ifdef HAVE_SYS_TYPES_H # include #endif #ifdef HAVE_NETINET_IN_H # include #endif #include #include "packet.h" #include "conversation.h" static int proto_tftp = -1; static int hf_tftp_opcode = -1; static int hf_tftp_source_file = -1; static int hf_tftp_destination_file = -1; static int hf_tftp_transfer_type = -1; static int hf_tftp_blocknum = -1; static int hf_tftp_error_code = -1; static int hf_tftp_error_string = -1; static gint ett_tftp = -1; #define UDP_PORT_TFTP 69 #define TFTP_RRQ 1 #define TFTP_WRQ 2 #define TFTP_DATA 3 #define TFTP_ACK 4 #define TFTP_ERROR 5 #define TFTP_OACK 6 static const value_string tftp_opcode_vals[] = { { TFTP_RRQ, "Read Request" }, { TFTP_WRQ, "Write Request" }, { TFTP_DATA, "Data Packet" }, { TFTP_ACK, "Acknowledgement" }, { TFTP_ERROR, "Error Code" }, { TFTP_OACK, "Option Acknowledgement" }, { 0, NULL } }; static const value_string tftp_error_code_vals[] = { { 0, "Not defined" }, { 1, "File not found" }, { 2, "Access violation" }, { 3, "Disk full or allocation exceeded" }, { 4, "Illegal TFTP Operation" }, { 5, "Unknown transfer ID" }, { 6, "File already exists" }, { 7, "No such user" }, { 0, NULL } }; static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree); static void dissect_tftp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_tree *tftp_tree; proto_item *ti; conversation_t *conversation; gint offset = 0; guint16 opcode; u_int i1; CHECK_DISPLAY_AS_DATA(proto_tftp, tvb, pinfo, tree); pinfo->current_proto = "TFTP"; /* * The first TFTP packet goes to the TFTP port; the second one * comes from some *other* port, but goes back to the same * IP address and port as the ones from which the first packet * came; all subsequent packets go between those two IP addresses * and ports. * * If this packet went to the TFTP port, we check to see if * there's already a conversation with the source IP address * and port of this packet, the destination IP address of this * packet, and any destination UDP port. If not, we create * one, with a wildcard UDP port, and give it the TFTP dissector * as a dissector. */ if (pinfo->destport == UDP_PORT_TFTP) { conversation = find_conversation(&pinfo->src, &pinfo->dst, PT_UDP, pinfo->srcport, 0, NO_DST_PORT); if (conversation == NULL) { conversation = conversation_new(&pinfo->src, &pinfo->dst, PT_UDP, pinfo->srcport, 0, NULL, NO_DST_PORT); conversation_set_dissector(conversation, dissect_tftp); } } if (check_col(pinfo->fd, COL_PROTOCOL)) col_set_str(pinfo->fd, COL_PROTOCOL, "TFTP"); opcode = tvb_get_ntohs(tvb, offset); if (check_col(pinfo->fd, COL_INFO)) { col_add_fstr(pinfo->fd, COL_INFO, "TFTP %s", val_to_str(opcode, tftp_opcode_vals, "Unknown (0x%04x)")); } if (tree) { ti = proto_tree_add_item(tree, proto_tftp, tvb, offset, tvb_length_remaining(tvb, offset), FALSE); tftp_tree = proto_item_add_subtree(ti, ett_tftp); proto_tree_add_uint(tftp_tree, hf_tftp_opcode, tvb, offset, 2, opcode); offset += 2; switch (opcode) { case TFTP_RRQ: i1 = tvb_strsize(tvb, offset); proto_tree_add_item(tftp_tree, hf_tftp_source_file, tvb, offset, i1, FALSE); offset += i1; i1 = tvb_strsize(tvb, offset); ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type, tvb, offset, i1, FALSE); offset += i1; tftp_dissect_options(tvb, offset, tftp_tree); break; case TFTP_WRQ: i1 = tvb_strsize(tvb, offset); proto_tree_add_item(tftp_tree, hf_tftp_destination_file, tvb, offset, i1, FALSE); offset += i1; i1 = tvb_strsize(tvb, offset); ti = proto_tree_add_item(tftp_tree, hf_tftp_transfer_type, tvb, offset, i1, FALSE); offset += i1; tftp_dissect_options(tvb, offset, tftp_tree); break; case TFTP_DATA: proto_tree_add_item(tftp_tree, hf_tftp_blocknum, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_text(tftp_tree, tvb, offset, tvb_length_remaining(tvb, offset), "Data (%d bytes)", tvb_length_remaining(tvb, offset)); break; case TFTP_ACK: proto_tree_add_item(tftp_tree, hf_tftp_blocknum, tvb, offset, 2, FALSE); break; case TFTP_ERROR: proto_tree_add_item(tftp_tree, hf_tftp_error_code, tvb, offset, 2, FALSE); offset += 2; i1 = tvb_strsize(tvb, offset); proto_tree_add_item(tftp_tree, hf_tftp_error_string, tvb, offset, i1, FALSE); break; case TFTP_OACK: tftp_dissect_options(tvb, offset, tftp_tree); break; default: proto_tree_add_text(tftp_tree, tvb, offset, tvb_length_remaining(tvb, offset), "Data (%d bytes)", tvb_length_remaining(tvb, offset)); break; } } } static void tftp_dissect_options(tvbuff_t *tvb, int offset, proto_tree *tree) { int option_len, value_len; int value_offset; while (tvb_offset_exists(tvb, offset)) { option_len = tvb_strsize(tvb, offset); /* length of option */ value_offset = offset + option_len; value_len = tvb_strsize(tvb, value_offset); /* length of value */ proto_tree_add_text(tree, tvb, offset, option_len+value_len, "Option: %s = %s", tvb_get_ptr(tvb, offset, option_len), tvb_get_ptr(tvb, value_offset, value_len)); offset += option_len + value_len; } } void proto_register_tftp(void) { static hf_register_info hf[] = { { &hf_tftp_opcode, { "Opcode", "tftp.opcode", FT_UINT16, BASE_DEC, VALS(tftp_opcode_vals), 0x0, "TFTP message type" }}, { &hf_tftp_source_file, { "Source File", "tftp.source_file", FT_STRINGZ, BASE_DEC, NULL, 0x0, "TFTP source file name" }}, { &hf_tftp_destination_file, { "DESTINATION File", "tftp.destination_file", FT_STRINGZ, BASE_DEC, NULL, 0x0, "TFTP source file name" }}, { &hf_tftp_transfer_type, { "Type", "tftp.type", FT_STRINGZ, BASE_DEC, NULL, 0x0, "TFTP transfer type" }}, { &hf_tftp_blocknum, { "Block", "tftp.block", FT_UINT16, BASE_DEC, NULL, 0x0, "Block number" }}, { &hf_tftp_error_code, { "Error code", "tftp.error.code", FT_UINT16, BASE_DEC, VALS(tftp_error_code_vals), 0x0, "Error code in case of TFTP error message" }}, { &hf_tftp_error_string, { "Error message", "tftp.error.message", FT_STRINGZ, BASE_DEC, NULL, 0x0, "Error string in case of TFTP error message" }} }; static gint *ett[] = { &ett_tftp, }; proto_tftp = proto_register_protocol("Trivial File Transfer Protocol", "TFTP", "tftp"); proto_register_field_array(proto_tftp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_tftp(void) { dissector_add("udp.port", UDP_PORT_TFTP, dissect_tftp, proto_tftp); }