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wireshark/epan/dissectors/packet-cattp.c

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/* packet-cattp.c
* Routines for packet dissection of
* ETSI TS 102 127 v6.13.0 (Release 6 / 2009-0r45)
* Card Application Toolkit - Transport Protocol over UDP
*
* Copyright 2014-2014 by Sebastian Kloeppel <sk [at] nakedape.net>
* Cristina E. Vintila <cristina.vintila [at] gmail.com>
*
* 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>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <epan/in_cksum.h>
#define CATTP_SHORTNAME "CAT-TP"
#define CATTP_HBLEN 18
#define F_SYN 0x80
#define F_ACK 0x40
#define F_EAK 0x20
#define F_RST 0x10
#define F_NUL 0x08
#define F_SEG 0x04
/* bit masks for the first header byte. */
#define M_FLAGS 0xFC /* flags only, no version */
#define M_PDU_SYN 0xB8 /* SYN (ACK, SEG dont care) without version */
#define M_PDU_ACK 0xD0 /* ACK (EAK, SEG, NUL dont care) without version */
#define M_PDU_RST 0xBC /* RST (ACK dont care) without version */
#define M_VERSION 0x03 /* only Version */
#define ICCID_PREFIX 0x98
static int proto_cattp = -1;
static gint ett_cattp = -1;
static gint ett_cattp_id = -1;
static gint ett_cattp_flags = -1;
static gint ett_cattp_eaks = -1;
static int hf_cattp_flags = -1;
/* flag components */
static int hf_cattp_flag_syn = -1;
static int hf_cattp_flag_ack = -1;
static int hf_cattp_flag_eak = -1;
static int hf_cattp_flag_rst = -1;
static int hf_cattp_flag_nul = -1;
static int hf_cattp_flag_seg = -1;
static int hf_cattp_version = -1;
/* structure of flag components */
static int * const cattp_flags[] = {
&hf_cattp_flag_syn,
&hf_cattp_flag_ack,
&hf_cattp_flag_eak,
&hf_cattp_flag_rst,
&hf_cattp_flag_nul,
&hf_cattp_flag_seg,
&hf_cattp_version,
NULL
};
static int hf_cattp_hlen = -1;
static int hf_cattp_srcport = -1;
static int hf_cattp_dstport = -1;
static int hf_cattp_datalen = -1;
static int hf_cattp_seq = -1;
static int hf_cattp_ack = -1;
static int hf_cattp_windowsize = -1;
static int hf_cattp_checksum = -1;
static int hf_cattp_checksum_status = -1;
static int hf_cattp_identification = -1;
static int hf_cattp_iccid = -1;
static int hf_cattp_idlen = -1;
static int hf_cattp_maxpdu = -1;
static int hf_cattp_maxsdu = -1;
static int hf_cattp_rc = -1;
static int hf_cattp_eaklen = -1;
static int hf_cattp_eaks = -1;
static expert_field ei_cattp_checksum = EI_INIT;
/* Preference to control whether to check the CATTP checksum */
static gboolean cattp_check_checksum = TRUE;
/* Reason code mapping */
static const value_string cattp_reset_reason[] = {
{ 0, "Normal Ending" },
{ 1, "Connection set-up failed, illegal parameters" },
{ 2, "Temporarily unable to set up this connection" },
{ 3, "Requested Port not available" },
{ 4, "Unexpected PDU received" },
{ 5, "Maximum retries exceeded" },
{ 6, "Version not supported" },
{ 7, "RFU" },
{ 0, NULL }
};
static const unit_name_string units_pdu = { "PDU", "PDUs" };
/* Forward declartion due to use of heuristic dissection preference. */
void proto_reg_handoff_cattp(void);
void proto_register_cattp(void);
/* Dissection of SYN PDUs */
static guint32
dissect_cattp_synpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *cattp_tree, guint32 offset)
{
proto_item *idi, *id_tree;
guint8 idlen;
proto_tree_add_item(cattp_tree, hf_cattp_maxpdu, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cattp_tree, hf_cattp_maxsdu, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
idlen = tvb_get_guint8(tvb, offset);
idi = proto_tree_add_uint(cattp_tree, hf_cattp_idlen, tvb, offset, 1, idlen);
offset += 1;
col_append_fstr(pinfo->cinfo, COL_INFO, " IdLen=%u ", idlen);
id_tree = proto_item_add_subtree(idi, ett_cattp_id);
if (idlen > 0) {
guint8 first_id_byte;
first_id_byte = tvb_get_guint8(tvb, offset);
proto_tree_add_item(id_tree, hf_cattp_identification, tvb, offset, idlen, ENC_NA);
/* Optional code. Checks whether identification field may be an ICCID.
* It has to be considered to move this logic to another layer / dissector.
* However it is common to send ICCID as Identification for OTA download. */
if (idlen <= 10 && idlen >= 9 && ICCID_PREFIX == first_id_byte) {
wmem_strbuf_t *buf;
int i;
buf = wmem_strbuf_new(wmem_packet_scope(), "");
/* switch nibbles */
for (i = 0; i < idlen; i++) {
guint8 c, n;
c = tvb_get_guint8(tvb, offset + i);
n = ((c & 0xF0) >> 4) + ((c & 0x0F) << 4);
wmem_strbuf_append_printf(buf, "%02X", n);
}
proto_tree_add_string(id_tree, hf_cattp_iccid, tvb, offset,
idlen, wmem_strbuf_get_str(buf));
}
offset += idlen;
}
return offset;
}
/* Dissection of Extended Acknowledgement PDUs */
static guint32
dissect_cattp_eakpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *cattp_tree, guint32 offset, guint8 hlen)
{
proto_item *eaki;
guint8 eak_count;
eak_count = (hlen - offset) >> 1;
eaki = proto_tree_add_uint(cattp_tree, hf_cattp_eaklen, tvb, offset, eak_count * 2, eak_count);
if (eak_count > 0) {
proto_item *eak_tree;
int i;
col_append_fstr(pinfo->cinfo, COL_INFO, " EAKs=%u", eak_count);
eak_tree = proto_item_add_subtree(eaki, ett_cattp_eaks);
for (i = 0; i < eak_count; i++) {
proto_tree_add_item(eak_tree, hf_cattp_eaks, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
}
return offset;
}
/* Dissection of Extended Acknowledgement PDUs */
static guint32
dissect_cattp_rstpdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *cattp_tree, guint32 offset)
{
guint8 rc;
const gchar *rc_str;
rc = tvb_get_guint8(tvb, offset); /* reason code of RST */
rc_str = val_to_str(rc, cattp_reset_reason, "Unknown reason code: 0x%02x");
col_append_fstr(pinfo->cinfo, COL_INFO, " Reason=\"%s\" ", rc_str);
proto_tree_add_item(cattp_tree, hf_cattp_rc, tvb, offset, 1, ENC_BIG_ENDIAN);
return ++offset;
}
/* Dissection of the base header */
static int
dissect_cattp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
const char *pdutype = "[Unknown PDU]";
proto_item *ti, *cattp_tree;
guint32 offset;
vec_t cksum_vec[1];
int header_offset;
guint cksum_data_len;
guint8 flags, first_byte, hlen, ver;
guint16 plen, ackno, seqno, wsize, sport, dport;
col_set_str(pinfo->cinfo, COL_PROTOCOL, CATTP_SHORTNAME);
/* Clear out stuff in the info column */
col_clear(pinfo->cinfo, COL_INFO);
hlen = tvb_get_guint8(tvb, 3); /* lookahead header len. */
offset = 0;
ti = proto_tree_add_protocol_format(tree, proto_cattp, tvb, offset, hlen,
"Card Application Toolkit Transport Protocol");
cattp_tree = proto_item_add_subtree(ti, ett_cattp);
/* render flags tree */
first_byte = tvb_get_guint8(tvb, offset);
flags = first_byte & M_FLAGS; /* discard version from first byte for flags */
ver = first_byte & M_VERSION; /* discard flags for version */
proto_tree_add_bitmask(cattp_tree, tvb, offset, hf_cattp_flags, ett_cattp_flags, cattp_flags, ENC_BIG_ENDIAN);
offset += 3; /* skip RFU and header len */
/* Header length, varies for SYN(identification) and EAKs */
proto_tree_add_uint(cattp_tree, hf_cattp_hlen, tvb, offset, 1, hlen);
offset += 1;
/* Parse cattp source port. */
sport = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_srcport, tvb, offset, 2, sport);
offset += 2;
/* Parse cattp destination port. */
dport = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_dstport, tvb, offset, 2, dport);
offset += 2;
proto_item_append_text(ti, " (v%u, Src Port: %u, Dst Port: %u)", ver, sport, dport);
col_add_fstr(pinfo->cinfo, COL_INFO, "%u > %u ", sport, dport);
/* Parse length of payload. */
plen = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_datalen, tvb, offset, 2, plen);
offset += 2;
/* Parse sequence number. */
seqno = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_seq, tvb, offset, 2, seqno);
offset += 2;
/* Parse acknowledgement number. */
ackno = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_ack, tvb, offset, 2, ackno);
offset += 2;
/* Parse window size. */
wsize = tvb_get_ntohs(tvb, offset);
proto_tree_add_uint(cattp_tree, hf_cattp_windowsize, tvb, offset, 2, wsize);
offset += 2;
if (flags & F_SYN)
pdutype = "[SYN PDU]";
else if (flags & F_ACK)
pdutype = "[ACK PDU]";
else if (flags & F_RST)
pdutype = "[RST PDU]";
col_append_fstr(pinfo->cinfo, COL_INFO, "%s Flags=0x%02X Ack=%u Seq=%u WSize=%u", pdutype, flags, ackno, seqno, wsize);
/* Parse and verify checksum */
header_offset = 0;
cksum_data_len = hlen + plen;
if (!cattp_check_checksum) {
/* We have turned checksum checking off; we do NOT checksum it. */
proto_tree_add_checksum(cattp_tree, tvb, offset, hf_cattp_checksum, hf_cattp_checksum_status, &ei_cattp_checksum,
pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
} else {
/* We haven't turned checksum checking off; checksum it. */
/* Unlike TCP, CATTP does not make use of a pseudo-header for checksum */
SET_CKSUM_VEC_TVB(cksum_vec[0], tvb, header_offset, cksum_data_len);
proto_tree_add_checksum(cattp_tree, tvb, offset, hf_cattp_checksum, hf_cattp_checksum_status, &ei_cattp_checksum,
pinfo, in_cksum(cksum_vec, 1), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
} /* End of checksum code */
offset += 2;
if (flags & F_SYN)
offset = dissect_cattp_synpdu(tvb, pinfo, cattp_tree, offset);
else if (flags & F_EAK)
offset = dissect_cattp_eakpdu(tvb, pinfo, cattp_tree, offset, hlen);
else if (flags & F_RST)
offset = dissect_cattp_rstpdu(tvb, pinfo, cattp_tree, offset);
/* for other PDU types nothing special to be displayed in detail tree. */
if (plen > 0) { /* Call generic data handle if data exists. */
col_append_fstr(pinfo->cinfo, COL_INFO, " DataLen=%u", plen);
tvb = tvb_new_subset_remaining(tvb, offset);
call_data_dissector(tvb, pinfo, tree);
}
return tvb_captured_length(tvb);
}
/* The heuristic dissector function checks if the UDP packet may be a cattp packet */
static gboolean
dissect_cattp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
if (tvb_captured_length(tvb) >= CATTP_HBLEN) { /* check of data is big enough for base header. */
guint8 flags, ver, hlen;
guint16 plen;
hlen = tvb_get_guint8(tvb, 3); /* header len */
plen = tvb_get_ntohs(tvb, 8); /* payload len */
if (hlen+plen != tvb_reported_length(tvb)) /* check if data length is ok. */
return FALSE;
/* ETSI TS 102 127 V15.0.0 and earlier releases say explicitly that
the version bits must be 0. */
ver = tvb_get_guint8(tvb, 0) & M_VERSION;
if (ver != 0)
return FALSE;
flags = tvb_get_guint8(tvb, 0) & M_FLAGS;
if ( (flags & M_PDU_SYN) == F_SYN ||
(flags & M_PDU_RST) == F_RST ||
(flags & M_PDU_ACK) == F_ACK ) { /* check if flag combi is valid */
dissect_cattp(tvb, pinfo, tree, data);
return TRUE;
}
}
return FALSE;
}
/* Function to register the dissector, called by infrastructure. */
void
proto_register_cattp(void)
{
static hf_register_info hf[] = {
{
&hf_cattp_flags,
{
"Flags", "cattp.flags", FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_flag_syn,
{
"Synchronize Flag", "cattp.flags.syn", FT_UINT8, BASE_DEC, NULL, F_SYN,
NULL, HFILL
}
},
{
&hf_cattp_flag_ack,
{
"Acknowledge Flag", "cattp.flags.ack", FT_UINT8, BASE_DEC, NULL, F_ACK,
NULL, HFILL
}
},
{
&hf_cattp_flag_eak,
{
"Extended Acknowledge Flag", "cattp.flags.eak", FT_UINT8, BASE_DEC, NULL, F_EAK,
NULL, HFILL
}
},
{
&hf_cattp_flag_rst,
{
"Reset Flag", "cattp.flags.rst", FT_UINT8, BASE_DEC, NULL, F_RST,
NULL, HFILL
}
},
{
&hf_cattp_flag_nul,
{
"NULL Flag", "cattp.flags.nul", FT_UINT8, BASE_DEC, NULL, F_NUL,
NULL, HFILL
}
},
{
&hf_cattp_flag_seg,
{
"Segmentation Flag", "cattp.flags.seg", FT_UINT8, BASE_DEC, NULL, F_SEG,
NULL, HFILL
}
},
{
&hf_cattp_version,
{
"Version", "cattp.version", FT_UINT8, BASE_HEX, NULL, M_VERSION,
NULL, HFILL
}
},
{
&hf_cattp_hlen,
{
"Header Length", "cattp.hlen", FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_srcport,
{
"Source Port", "cattp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_dstport,
{
"Destination Port", "cattp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_datalen,
{
"Data Length", "cattp.datalen", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_seq,
{
"Sequence Number", "cattp.seq", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_ack,
{
"Acknowledgement Number", "cattp.ack", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_windowsize,
{
"Window Size", "cattp.windowsize", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_checksum,
{
"Checksum", "cattp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_checksum_status,
{
"Checksum Status", "cattp.checksum.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0,
NULL, HFILL
}
},
{
&hf_cattp_identification,
{
"Identification", "cattp.identification", FT_BYTES, BASE_NONE, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_iccid,
{
"ICCID", "cattp.iccid", FT_STRING, BASE_NONE, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_maxpdu,
{
"Maxpdu", "cattp.maxpdu", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_maxsdu,
{
"Maxsdu", "cattp.maxsdu", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_rc,
{
"Reason Code", "cattp.rc", FT_UINT8, BASE_DEC, VALS(cattp_reset_reason), 0x0,
NULL, HFILL
}
},
{
&hf_cattp_idlen,
{
"Identification Length", "cattp.idlen", FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_eaks,
{
"Acknowledgement Number", "cattp.eak", FT_UINT16, BASE_DEC, NULL, 0x0,
NULL, HFILL
}
},
{
&hf_cattp_eaklen,
{
"Extended Acknowledgement Numbers", "cattp.eaks", FT_UINT16, BASE_DEC|BASE_UNIT_STRING, &units_pdu, 0x0,
NULL, HFILL
}
}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_cattp,
&ett_cattp_flags,
&ett_cattp_id,
&ett_cattp_eaks
};
static ei_register_info ei[] = {
{ &ei_cattp_checksum, { "cattp.bad_checksum", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }},
};
module_t *cattp_module;
expert_module_t* expert_cattp;
proto_cattp = proto_register_protocol (
"ETSI Card Application Toolkit Transport Protocol", /* name */
CATTP_SHORTNAME, /* short name */
"cattp" /* abbrev */
);
proto_register_field_array(proto_cattp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_cattp = expert_register_protocol(proto_cattp);
expert_register_field_array(expert_cattp, ei, array_length(ei));
cattp_module = prefs_register_protocol(proto_cattp, NULL);
prefs_register_bool_preference(cattp_module, "checksum",
"Validate checksum of all messages",
"Whether the checksum of all messages should be validated or not",
&cattp_check_checksum);
prefs_register_obsolete_preference(cattp_module, "enable");
}
/* Handoff */
void
proto_reg_handoff_cattp(void)
{
dissector_handle_t cattp_handle;
/* Create dissector handle */
cattp_handle = create_dissector_handle(dissect_cattp, proto_cattp);
heur_dissector_add("udp", dissect_cattp_heur, "CAT-TP over UDP", "cattp_udp", proto_cattp, HEURISTIC_DISABLE);
dissector_add_for_decode_as_with_preference("udp.port", cattp_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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