diff options
Diffstat (limited to 'plugins/epan/irda/packet-sir.c')
| -rw-r--r-- | plugins/epan/irda/packet-sir.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/plugins/epan/irda/packet-sir.c b/plugins/epan/irda/packet-sir.c new file mode 100644 index 0000000000..54457069e0 --- /dev/null +++ b/plugins/epan/irda/packet-sir.c @@ -0,0 +1,248 @@ +/** Decode IrDA Serial Infrared (SIR) wrapped packets. + * @author Shaun Jackman <sjackman@debian.org> + * @copyright Copyright 2004 Shaun Jackman + * @license GPL + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "config.h" + +#include <epan/packet.h> +#include <epan/expert.h> +#include <epan/crc16-tvb.h> + +/** Serial infrared port. */ +#define TCP_PORT_SIR 6417 /* Not IANA registered */ + + +/** Beginning of frame. */ +#define SIR_BOF 0xc0 + +/** End of frame. */ +#define SIR_EOF 0xc1 + +/** Control escape. */ +#define SIR_CE 0x7d + +/** Escapes this character. */ +#define SIR_ESCAPE(x) ((x)^0x20) + +void proto_reg_handoff_irsir(void); +void proto_register_irsir(void); + +/** Protocol handles. */ +static dissector_handle_t irda_handle; +static dissector_handle_t sir_handle; + +/** Protocol fields. */ +static int proto_sir = -1; +static int ett_sir = -1; +static int hf_sir_bof = -1; +/* static int hf_sir_ce = -1; */ +static int hf_sir_eof = -1; +static int hf_sir_fcs = -1; +static int hf_sir_fcs_status = -1; +static int hf_sir_length = -1; +static int hf_sir_preamble = -1; + +static expert_field ei_sir_fcs = EI_INIT; + +/* Copied and renamed from proto.c because global value_strings don't work for plugins */ +static const value_string plugin_proto_checksum_vals[] = { + { PROTO_CHECKSUM_E_BAD, "Bad" }, + { PROTO_CHECKSUM_E_GOOD, "Good" }, + { PROTO_CHECKSUM_E_UNVERIFIED, "Unverified" }, + { PROTO_CHECKSUM_E_NOT_PRESENT, "Not present" }, + + { 0, NULL } +}; + + +/** Unescapes the data. */ +static tvbuff_t * +unescape_data(tvbuff_t *tvb, packet_info *pinfo) +{ + if (tvb_find_guint8(tvb, 0, -1, SIR_CE) == -1) { + return tvb; + } else { + guint length = tvb_captured_length(tvb); + guint offset; + guint8 *data = (guint8 *)wmem_alloc(pinfo->pool, length); + guint8 *dst = data; + tvbuff_t *next_tvb; + + for (offset = 0; offset < length; ) + { + guint8 c = tvb_get_guint8(tvb, offset++); + if ((c == SIR_CE) && (offset < length)) + c = SIR_ESCAPE(tvb_get_guint8(tvb, offset++)); + *dst++ = c; + } + + next_tvb = tvb_new_child_real_data(tvb, data, (guint) (dst-data), (guint) (dst-data)); + add_new_data_source(pinfo, next_tvb, "Unescaped SIR"); + return next_tvb; + } +} + + +/** Checksums the data. */ +static tvbuff_t * +checksum_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + int len = tvb_reported_length(tvb) - 2; + if (len < 0) + return tvb; + + proto_tree_add_checksum(tree, tvb, len, hf_sir_fcs, hf_sir_fcs_status, &ei_sir_fcs, pinfo, crc16_ccitt_tvb(tvb, len), + ENC_LITTLE_ENDIAN, PROTO_CHECKSUM_VERIFY); + + return tvb_new_subset_length(tvb, 0, len); +} + + +/** Dissects an SIR packet. */ +static int +dissect_sir(tvbuff_t *tvb, packet_info *pinfo, proto_tree *root, void* data _U_) +{ + gint offset = 0; + gint bof_offset; + gint eof_offset; + + while (tvb_reported_length_remaining(tvb, offset) > 0) { + bof_offset = tvb_find_guint8(tvb, offset, -1, SIR_BOF); + eof_offset = (bof_offset == -1) ? -1 : + tvb_find_guint8(tvb, bof_offset, -1, SIR_EOF); + + if (bof_offset == -1 || eof_offset == -1) { + if (pinfo->can_desegment) { + pinfo->desegment_offset = offset; + pinfo->desegment_len = 1; + } + return tvb_captured_length(tvb); + } else { + guint preamble_len = bof_offset - offset; + gint data_offset = bof_offset + 1; + tvbuff_t* next_tvb = tvb_new_subset_length_caplen(tvb, + data_offset, eof_offset - data_offset, -1); + next_tvb = unescape_data(next_tvb, pinfo); + if (root) { + guint data_len = tvb_reported_length(next_tvb) < 2 ? 0 : + tvb_reported_length(next_tvb) - 2; + proto_tree* ti = proto_tree_add_protocol_format(root, + proto_sir, tvb, offset, eof_offset - offset + 1, + "Serial Infrared, Len: %d", data_len); + proto_tree* tree = proto_item_add_subtree(ti, ett_sir); + if (preamble_len > 0) + proto_tree_add_item(tree, hf_sir_preamble, tvb, + offset, preamble_len, ENC_NA); + proto_tree_add_item(tree, hf_sir_bof, tvb, + bof_offset, 1, ENC_BIG_ENDIAN); + proto_tree_add_uint(tree, hf_sir_length, + next_tvb, 0, data_len, data_len); + next_tvb = checksum_data(next_tvb, pinfo, tree); + proto_tree_add_item(tree, hf_sir_eof, tvb, + eof_offset, 1, ENC_BIG_ENDIAN); + } else { + next_tvb = checksum_data(next_tvb, pinfo, NULL); + } + call_dissector(irda_handle, next_tvb, pinfo, root); + } + offset = eof_offset + 1; + } + return tvb_captured_length(tvb); +} + + +/** Registers this dissector with the parent dissector. */ +void +proto_reg_handoff_irsir(void) +{ + dissector_add_uint_with_preference("tcp.port", TCP_PORT_SIR, sir_handle); + + irda_handle = find_dissector("irda"); +} + + +/** Initializes this protocol. */ +void +proto_register_irsir(void) +{ + static gint* ett[] = { &ett_sir }; + + static hf_register_info hf_sir[] = { + { &hf_sir_bof, + { "Beginning of frame", "sir.bof", + FT_UINT8, BASE_HEX, NULL, 0, + NULL, HFILL }}, +#if 0 + { &hf_sir_ce, + { "Command escape", "sir.ce", + FT_UINT8, BASE_HEX, NULL, 0, + NULL, HFILL }}, +#endif + { &hf_sir_eof, + { "End of frame", "sir.eof", + FT_UINT8, BASE_HEX, NULL, 0, + NULL, HFILL }}, + { &hf_sir_fcs, + { "Frame check sequence", "sir.fcs", + FT_UINT16, BASE_HEX, NULL, 0, + NULL, HFILL }}, + { &hf_sir_fcs_status, + { "Frame check sequence Status", "sir.fcs.status", + FT_UINT8, BASE_NONE, VALS(plugin_proto_checksum_vals), 0x0, + NULL, HFILL }}, + { &hf_sir_length, + { "Length", "sir.length", + FT_UINT16, BASE_DEC, NULL, 0, + NULL, HFILL }}, + { &hf_sir_preamble, + { "Preamble", "sir.preamble", + FT_BYTES, BASE_NONE, NULL, 0, + NULL, HFILL }} + }; + + static ei_register_info ei[] = { + { &ei_sir_fcs, { "sir.bad_checksum", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }}, + }; + + expert_module_t* expert_sir; + + proto_sir = proto_register_protocol("Serial Infrared", "SIR", "sir"); + sir_handle = register_dissector("sir", dissect_sir, proto_sir); + proto_register_subtree_array(ett, array_length(ett)); + proto_register_field_array( proto_sir, hf_sir, array_length(hf_sir)); + expert_sir = expert_register_protocol(proto_sir); + expert_register_field_array(expert_sir, ei, array_length(ei)); +} + +/* + * Editor modelines - http://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: + */ |