/* packet-dsi.c * Routines for dsi packet dissection * Copyright 2001, Randy McEoin * * $Id: packet-dsi.c,v 1.15 2002/04/28 22:10:00 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * Copied from packet-pop.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 #include #ifdef HAVE_SYS_TYPES_H # include #endif #ifdef HAVE_NETINET_IN_H # include #endif #include #include #include "prefs.h" #include "packet-frame.h" #include "packet-afp.h" /* The information in this module (DSI) comes from: AFP 2.1 & 2.2.pdf contained in AppleShare_IP_6.3_SDK available from http://www.apple.com The netatalk source code by Wesley Craig & Adrian Sun * What a Data Stream Interface packet looks like: * 0 32 * |-------------------------------| * |flags |command| requestID | * |-------------------------------| * |error code/enclosed data offset| * |-------------------------------| * |total data length | * |-------------------------------| * |reserved field | * |-------------------------------| */ static int proto_dsi = -1; static int hf_dsi_flags = -1; static int hf_dsi_command = -1; static int hf_dsi_requestid = -1; static int hf_dsi_offset = -1; static int hf_dsi_error = -1; static int hf_dsi_length = -1; static int hf_dsi_reserved = -1; static gint ett_dsi = -1; /* desegmentation of DSI */ static gboolean dsi_desegment = TRUE; static dissector_handle_t data_handle; static dissector_handle_t afp_handle; #define TCP_PORT_DSI 548 #define DSI_BLOCKSIZ 16 /* DSI flags */ #define DSIFL_REQUEST 0x00 #define DSIFL_REPLY 0x01 #define DSIFL_MAX 0x01 /* DSI Commands */ #define DSIFUNC_CLOSE 1 /* DSICloseSession */ #define DSIFUNC_CMD 2 /* DSICommand */ #define DSIFUNC_STAT 3 /* DSIGetStatus */ #define DSIFUNC_OPEN 4 /* DSIOpenSession */ #define DSIFUNC_TICKLE 5 /* DSITickle */ #define DSIFUNC_WRITE 6 /* DSIWrite */ #define DSIFUNC_ATTN 8 /* DSIAttention */ #define DSIFUNC_MAX 8 /* largest command */ static const value_string flag_vals[] = { {DSIFL_REQUEST, "Request" }, {DSIFL_REPLY, "Reply" }, {0, NULL } }; static const value_string func_vals[] = { {DSIFUNC_CLOSE, "CloseSession" }, {DSIFUNC_CMD, "Command" }, {DSIFUNC_STAT, "GetStatus" }, {DSIFUNC_OPEN, "OpenSession" }, {DSIFUNC_TICKLE, "Tickle" }, {DSIFUNC_WRITE, "Write" }, {DSIFUNC_ATTN, "Attention" }, {0, NULL } }; static void dissect_dsi_packet(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_tree *dsi_tree; proto_item *ti; guint8 dsi_flags,dsi_command; guint16 dsi_requestid; gint32 dsi_code; guint32 dsi_length; guint32 dsi_reserved; struct aspinfo aspinfo; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "DSI"); if (check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); dsi_flags = tvb_get_guint8(tvb, 0); dsi_command = tvb_get_guint8(tvb, 1); dsi_requestid = tvb_get_ntohs(tvb, 2); dsi_code = tvb_get_ntohl(tvb, 4); dsi_length = tvb_get_ntohl(tvb, 8); dsi_reserved = tvb_get_ntohl(tvb, 12); if (check_col(pinfo->cinfo, COL_INFO)) { col_add_fstr(pinfo->cinfo, COL_INFO, "%s %s (%u)", val_to_str(dsi_flags, flag_vals, "Unknown flag (0x%02x)"), val_to_str(dsi_command, func_vals, "Unknown function (0x%02x)"), dsi_requestid); } if (tree) { ti = proto_tree_add_item(tree, proto_dsi, tvb, 0, -1, FALSE); dsi_tree = proto_item_add_subtree(ti, ett_dsi); proto_tree_add_uint(dsi_tree, hf_dsi_flags, tvb, 0, 1, dsi_flags); proto_tree_add_uint(dsi_tree, hf_dsi_command, tvb, 1, 1, dsi_command); proto_tree_add_uint(dsi_tree, hf_dsi_requestid, tvb, 2, 2, dsi_requestid); switch (dsi_flags) { case DSIFL_REQUEST: proto_tree_add_int(dsi_tree, hf_dsi_offset, tvb, 4, 4, dsi_code); break; case DSIFL_REPLY: proto_tree_add_int(dsi_tree, hf_dsi_error, tvb, 4, 4, dsi_code); break; } proto_tree_add_uint_format(dsi_tree, hf_dsi_length, tvb, 8, 4, dsi_length, "Length: %u bytes", dsi_length); proto_tree_add_uint(dsi_tree, hf_dsi_reserved, tvb, 12, 4, dsi_reserved); } else dsi_tree = tree; if (dsi_command == DSIFUNC_CMD || dsi_command == DSIFUNC_WRITE) { tvbuff_t *new_tvb; int len = tvb_reported_length_remaining(tvb,DSI_BLOCKSIZ); aspinfo.reply = dsi_flags & 1; aspinfo.command = dsi_command; aspinfo.seq = dsi_requestid; aspinfo.code = dsi_code; pinfo->private_data = &aspinfo; proto_item_set_len(dsi_tree, DSI_BLOCKSIZ); new_tvb = tvb_new_subset(tvb, DSI_BLOCKSIZ,-1,len); call_dissector(afp_handle, new_tvb, pinfo, tree); } else if (tree) { call_dissector(data_handle,tvb_new_subset(tvb, DSI_BLOCKSIZ,-1,tvb_reported_length_remaining(tvb,DSI_BLOCKSIZ)), pinfo, dsi_tree); } } static void dissect_dsi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { volatile int offset = 0; int length_remaining; guint32 plen; int length; tvbuff_t *next_tvb; while (tvb_reported_length_remaining(tvb, offset) != 0) { length_remaining = tvb_length_remaining(tvb, offset); /* * Can we do reassembly? */ if (dsi_desegment && pinfo->can_desegment) { /* * Yes - is the DSI header split across segment * boundaries? */ if (length_remaining < 12) { /* * Yes. Tell the TCP dissector where * the data for this message starts in * the data it handed us, and how many * more bytes we need, and return. */ pinfo->desegment_offset = offset; pinfo->desegment_len = 12 - length_remaining; return; } } /* * Get the length of the DSI packet. */ plen = tvb_get_ntohl(tvb, offset+8); /* * Can we do reassembly? */ if (dsi_desegment && pinfo->can_desegment) { /* * Yes - is the DSI packet split across segment * boundaries? */ if ((guint32)length_remaining < plen + 16) { /* * Yes. Tell the TCP dissector where * the data for this message starts in * the data it handed us, and how many * more bytes we need, and return. */ pinfo->desegment_offset = offset; pinfo->desegment_len = (plen + 16) - length_remaining; return; } } /* * Construct a tvbuff containing the amount of the payload * we have available. Make its reported length the * amount of data in the DSI packet. * * XXX - if reassembly isn't enabled. the subdissector * will throw a BoundsError exception, rather than a * ReportedBoundsError exception. We really want * a tvbuff where the length is "length", the reported * length is "plen + 16", and the "if the snapshot length * were infinite" length is the minimum of the * reported length of the tvbuff handed to us and "plen+16", * with a new type of exception thrown if the offset is * within the reported length but beyond that third length, * with that exception getting the "Unreassembled Packet" * error. */ length = length_remaining; if ((guint32)length > plen + 16) length = plen + 16; next_tvb = tvb_new_subset(tvb, offset, length, plen + 16); /* * Dissect the DSI packet. * * Catch the ReportedBoundsError exception; if this * particular message happens to get a ReportedBoundsError * exception, that doesn't mean that we should stop * dissecting DSI messages within this frame or chunk * of reassembled data. * * If it gets a BoundsError, we can stop, as there's nothing * more to see, so we just re-throw it. */ TRY { dissect_dsi_packet(next_tvb, pinfo, tree); } CATCH(BoundsError) { RETHROW; } CATCH(ReportedBoundsError) { show_reported_bounds_error(tvb, pinfo, tree); } ENDTRY; /* * Skip the DSI header and the payload. */ offset += plen + 16; } } void proto_register_dsi(void) { static hf_register_info hf[] = { { &hf_dsi_flags, { "Flags", "dsi.flags", FT_UINT8, BASE_HEX, VALS(flag_vals), 0x0, "Indicates request or reply.", HFILL }}, { &hf_dsi_command, { "Command", "dsi.command", FT_UINT8, BASE_DEC, VALS(func_vals), 0x0, "Represents a DSI command.", HFILL }}, { &hf_dsi_requestid, { "Request ID", "dsi.requestid", FT_UINT16, BASE_DEC, NULL, 0x0, "Keeps track of which request this is. Replies must match a Request. IDs must be generated in sequential order.", HFILL }}, { &hf_dsi_offset, { "Data offset", "dsi.data_offset", FT_INT32, BASE_DEC, NULL, 0x0, "Data offset", HFILL }}, { &hf_dsi_error, { "Error code", "dsi.error_code", FT_INT32, BASE_DEC, VALS(asp_error_vals), 0x0, "Error code", HFILL }}, { &hf_dsi_length, { "Length", "dsi.length", FT_UINT32, BASE_DEC, NULL, 0x0, "Total length of the data that follows the DSI header.", HFILL }}, { &hf_dsi_reserved, { "Reserved", "dsi.reserved", FT_UINT32, BASE_HEX, NULL, 0x0, "Reserved for future use. Should be set to zero.", HFILL }}, }; static gint *ett[] = { &ett_dsi, }; module_t *dsi_module; proto_dsi = proto_register_protocol("Data Stream Interface", "DSI", "dsi"); proto_register_field_array(proto_dsi, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); dsi_module = prefs_register_protocol(proto_dsi, NULL); prefs_register_bool_preference(dsi_module, "desegment", "Desegment all DSI messages spanning multiple TCP segments", "Whether the DSI dissector should desegment all messages spanning multiple TCP segments", &dsi_desegment); } void proto_reg_handoff_dsi(void) { static dissector_handle_t dsi_handle; dsi_handle = create_dissector_handle(dissect_dsi, proto_dsi); dissector_add("tcp.port", TCP_PORT_DSI, dsi_handle); data_handle = find_dissector("data"); afp_handle = find_dissector("afp"); }