/* 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 * Cristina E. Vintila * * Wireshark - Network traffic analyzer * By Gerald Combs * 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 #include #include #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 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; /* 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 } }; /* 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_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 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; 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_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, 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, 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_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_obsolete_preference(cattp_module, "enable"); } /* Handoff */ void proto_reg_handoff_cattp(void) { static gboolean initialized = FALSE; if (!initialized) { 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_ENABLE); dissector_add_for_decode_as("udp.port", cattp_handle); initialized = TRUE; } } /* * 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: */