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Diffstat (limited to 'epan/dissectors/packet-cattp.c')
-rw-r--r-- | epan/dissectors/packet-cattp.c | 606 |
1 files changed, 606 insertions, 0 deletions
diff --git a/epan/dissectors/packet-cattp.c b/epan/dissectors/packet-cattp.c new file mode 100644 index 0000000000..4b4aebf74b --- /dev/null +++ b/epan/dissectors/packet-cattp.c @@ -0,0 +1,606 @@ +/* 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 + * + * 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/prefs.h> +#include <epan/packet.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 dissector_handle_t cattp_handle; + +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 const int *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_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 dissector_handle_t data_handle; + +/* Preference to control whether to check the CATTP checksum */ +static gboolean cattp_check_checksum = TRUE; + +/* Preference to control whether to heuristically detect CATTP packets */ +static gboolean cattp_enable_heuristic_dissection = 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 } +}; + +/* Forward declartion due to use of heuristic dissection preference. */ +void proto_reg_handoff_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++; + + 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_format_value(cattp_tree, hf_cattp_eaklen, tvb, offset, eak_count * 2, + eak_count, "%u PDUs", 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 void +dissect_cattp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + const char* pdutype = "[Unknown PDU]"; + proto_item *ti, *cattp_tree; + guint32 offset; + gushort computed_chksum; + vec_t cksum_vec[1]; + int header_offset; + guint cksum_data_len; + guint8 flags, first_byte, hlen, ver; + guint16 plen, chksum, 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; + chksum = tvb_get_ntohs(tvb,offset); + if (!cattp_check_checksum) { + /* We have turned checksum checking off; we do NOT checksum it. */ + proto_tree_add_uint_format_value(cattp_tree, hf_cattp_checksum, tvb, offset, 2, + chksum,"0x%X [validation disabled]", chksum); + } 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); + computed_chksum = in_cksum(cksum_vec, 1); + + if (computed_chksum == 0) { + /* Checksum is valid */ + proto_tree_add_uint_format_value(cattp_tree, hf_cattp_checksum, tvb, offset, 2, + chksum,"0x%X [validated]", chksum); + } else { + /* Checksum is invalid. Let's compute the expected checksum, based on the data we have */ + proto_tree_add_uint_format_value(cattp_tree, hf_cattp_checksum, tvb, offset, 2, chksum, + "0x%X [incorrect, correct: 0x%X]", chksum, + in_cksum_shouldbe(chksum,computed_chksum)); + } + } /* 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_dissector(data_handle,tvb, pinfo, tree); + } +} + +/* 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 _U_) +{ + if (tvb_captured_length(tvb) >= CATTP_HBLEN) { /* check of data is big enough for base header. */ + guint8 flags, 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; + + 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); + return TRUE; + } + } + return FALSE; +} + +/* Function to register the dissector, called by plugin 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_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, NULL, 0x0, + NULL, HFILL + } + } + }; + + /* Setup protocol subtree array */ + static gint *ett[] = { + &ett_cattp, + &ett_cattp_flags, + &ett_cattp_id, + &ett_cattp_eaks + }; + + module_t *cattp_module; + + 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)); + + cattp_module = prefs_register_protocol(proto_cattp, proto_reg_handoff_cattp); + 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_bool_preference(cattp_module, "enable", + "Enable " CATTP_SHORTNAME " heuristic dissection", + "Enable " CATTP_SHORTNAME " heuristic dissection (default is enabled)", + &cattp_enable_heuristic_dissection); +} + +/* Handoff */ +void +proto_reg_handoff_cattp(void) +{ + static gboolean initialized = FALSE; + + if (!initialized) { + /* Create dissector handle */ + cattp_handle = create_dissector_handle(dissect_cattp, proto_cattp); + + /* find data handle */ + data_handle = find_dissector("data"); + + heur_dissector_add("udp",dissect_cattp_heur,proto_cattp); + dissector_add_for_decode_as("udp.port", cattp_handle); + initialized = TRUE; + } + + heur_dissector_set_enabled("udp",dissect_cattp_heur,proto_cattp, + cattp_enable_heuristic_dissection); +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 4 + * tab-width: 4 + * indent-tabs-mode: t + * End: + * + * vi: set shiftwidth=4 tabstop=4 expandtab: + * :indentSize=4:tabSize=4:noTabs=true: + */ |