/* packet-fr.c * Routines for Frame Relay dissection * * Copyright 2001, Paul Ionescu * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later * * References: * * https://web.archive.org/web/20150510093619/http://www.protocols.com/pbook/frame.htm * https://www.broadband-forum.org/wp-content/uploads/2018/12/FRF.3.2.pdf * ITU Recommendations Q.922 and Q.933 * RFC-1490 * RFC-2427 * Cisco encapsulation * https://web.archive.org/web/20030422173700/https://www.trillium.com/assets/legacyframe/white_paper/8771019.pdf */ #include "config.h" #include #include #include #include #include #include #include #include "packet-llc.h" #include "packet-chdlc.h" #include "packet-juniper.h" #include "packet-sflow.h" #include "packet-l2tp.h" #include #include #include void proto_register_fr(void); void proto_reg_handoff_fr(void); /* * Bits in the address field. */ #define FRELAY_EA 0x01 /* Address field extension bit */ #define FRELAY_UPPER_DLCI 0xFC /* Upper DLCI */ #define FRELAY_CR 0x02 /* Command/response bit in first octet */ #define FRELAY_SECOND_DLCI 0xF0 /* DLCI bits in FECN/BECN/DE octet */ #define FRELAY_FECN 0x08 /* Forward Explicit Congestion Notification */ #define FRELAY_BECN 0x04 /* Backward Explicit Congestion Notification */ #define FRELAY_DE 0x02 /* Discard Eligibility */ #define FRELAY_THIRD_DLCI 0xFE /* DLCI bits in third octet, if any */ #define FRELAY_LOWER_DLCI 0xFC /* Lower DLCI */ #define FRELAY_DC 0x02 /* DLCI or DL-CORE control indicator in last octet */ #define FROM_DCE 0x80 /* for direction setting */ static int proto_fr; static int ett_fr; static int ett_fr_address; static int ett_fr_control; static int hf_fr_ea; static int hf_fr_upper_dlci; static int hf_fr_cr; static int hf_fr_second_dlci; static int hf_fr_fecn; static int hf_fr_becn; static int hf_fr_de; static int hf_fr_third_dlci; static int hf_fr_dlcore_control; static int hf_fr_lower_dlci; static int hf_fr_dc; static int hf_fr_dlci; static int hf_fr_control; static int hf_fr_n_r; static int hf_fr_n_s; static int hf_fr_p; static int hf_fr_p_ext; static int hf_fr_f; static int hf_fr_f_ext; static int hf_fr_s_ftype; static int hf_fr_u_modifier_cmd; static int hf_fr_u_modifier_resp; static int hf_fr_ftype_i; static int hf_fr_ftype_s_u; static int hf_fr_ftype_s_u_ext; static int hf_fr_nlpid; static int hf_fr_oui; static int hf_fr_pid; static int hf_fr_snaptype; static int hf_fr_chdlctype; static int hf_fr_first_addr_octet; static int hf_fr_second_addr_octet; static int hf_fr_third_addr_octet; static expert_field ei_fr_bogus_address; static expert_field ei_fr_frame_relay_lapf; static expert_field ei_fr_frame_relay_xid; static dissector_handle_t eth_withfcs_handle; static dissector_handle_t gprs_ns_handle; static dissector_handle_t lapb_handle; static dissector_handle_t data_handle; static dissector_handle_t fr_handle; static capture_dissector_handle_t chdlc_cap_handle; static capture_dissector_handle_t eth_cap_handle; static dissector_table_t chdlc_subdissector_table; static dissector_table_t osinl_incl_subdissector_table; static dissector_table_t ethertype_subdissector_table; /* * Encapsulation type. * XXX - this should be per-DLCI as well. */ #define FRF_3_2 0 /* FRF 3.2 or Cisco HDLC */ #define GPRS_NS 1 /* GPRS Network Services (3GPP TS 08.16) */ #define RAW_ETHER 2 /* Raw Ethernet */ #define LAPB 3 /* T.617a-1994 Annex G encapsuation of LAPB */ static int fr_encap = FRF_3_2; static const true_false_string ctrl_string = { "DLCI Address", "Control" }; static const true_false_string ea_string = { "Last Octet", "More Follows" }; /* * This isn't the same as "nlpid_vals[]"; 0x08 is Q.933, not Q.931, * and 0x09 is LMI, not Q.2931, and we assume that it's an initial * protocol identifier, so 0x01 is T.70, not X.29. */ static const value_string fr_nlpid_vals[] = { { NLPID_NULL, "NULL" }, { NLPID_IPI_T_70, "T.70" }, /* XXX - IPI, or SPI? */ { NLPID_X_633, "X.633" }, { NLPID_Q_931, "Q.933" }, { NLPID_LMI, "LMI" }, { NLPID_Q_2119, "Q.2119" }, { NLPID_SNAP, "SNAP" }, { NLPID_ISO8473_CLNP, "CLNP" }, { NLPID_ISO9542_ESIS, "ESIS" }, { NLPID_ISO10589_ISIS, "ISIS" }, { NLPID_ISO10747_IDRP, "IDRP" }, { NLPID_ISO9542X25_ESIS, "ESIS (X.25)" }, { NLPID_ISO10030, "ISO 10030" }, { NLPID_ISO11577, "ISO 11577" }, { NLPID_COMPRESSED, "Data compression protocol" }, { NLPID_IP, "IP" }, { NLPID_IP6, "IPv6" }, { NLPID_PPP, "PPP" }, { 0, NULL }, }; static dissector_table_t fr_subdissector_table; static dissector_table_t fr_osinl_subdissector_table; static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, proto_item *ti, proto_tree *fr_tree, uint8_t fr_ctrl); static void dissect_lapf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree); static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree); /* Used only for U frames */ static const xdlc_cf_items fr_cf_items = { NULL, NULL, &hf_fr_p, &hf_fr_f, NULL, &hf_fr_u_modifier_cmd, &hf_fr_u_modifier_resp, NULL, &hf_fr_ftype_s_u }; /* Used only for I and S frames */ static const xdlc_cf_items fr_cf_items_ext = { &hf_fr_n_r, &hf_fr_n_s, &hf_fr_p_ext, &hf_fr_f_ext, &hf_fr_s_ftype, NULL, NULL, &hf_fr_ftype_i, &hf_fr_ftype_s_u_ext }; static bool capture_fr(const unsigned char *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header) { uint8_t fr_octet; uint32_t addr; uint8_t fr_ctrl; uint8_t fr_nlpid; /* * OK, fetch the address field - keep going until we get an EA bit. */ if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_octet = pd[offset]; if (fr_octet & FRELAY_EA) { /* * Bogus! There should be at least 2 octets. * XXX - is this FRF.12 frame relay fragmentation? If so, can * we handle that? */ return false; } /* * The first octet contains the upper 6 bits of the DLCI, as well * as the C/R bit. */ addr = (fr_octet & FRELAY_UPPER_DLCI) >> 2; offset++; /* * The second octet contains 4 more bits of DLCI, as well as FECN, * BECN, and DE. */ if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_octet = pd[offset]; addr = (addr << 4) | ((fr_octet & FRELAY_SECOND_DLCI) >> 4); offset++; if (!(fr_octet & FRELAY_EA)) { /* * We have 3 or more address octets. * * The third octet contains 7 more bits of DLCI if EA isn't set, * and lower DLCI or DL-CORE control plus the DLCI or DL-CORE * control indicator flag if EA is set. */ if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_octet = pd[offset]; if (!(fr_octet & FRELAY_EA)) { /* * 7 more bits of DLCI. */ addr = (addr << 7) | ((fr_octet & FRELAY_THIRD_DLCI) >> 1); offset++; if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_octet = pd[offset]; while (!(fr_octet & FRELAY_EA)) { /* * Bogus! More than 4 octets of address. */ offset++; if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_octet = pd[offset]; } } /* * Last octet - contains lower DLCI or DL-CORE control, DLCI or * DL-CORE control indicator flag. */ if (fr_octet & FRELAY_DC) { /* * DL-CORE. */ } else { /* * Last 6 bits of DLCI. */ addr = (addr << 6) | ((fr_octet & FRELAY_LOWER_DLCI) >> 2); } } switch (fr_encap) { case FRF_3_2: if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_ctrl = pd[offset]; if (fr_ctrl == XDLC_U) { offset++; /* * XXX - treat DLCI 0 specially? On DLCI 0, an NLPID of 0x08 * means Q.933, but on other circuits it could be the "for * protocols which do not have an NLPID assigned or do not * have a SNAP encapsulation" stuff from RFC 2427. */ if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_nlpid = pd[offset]; if (fr_nlpid == 0) { offset++; if (!BYTES_ARE_IN_FRAME(offset, len, 1)) return false; fr_nlpid = pd[offset]; } offset++; return try_capture_dissector("fr.nlpid", fr_nlpid, pd, offset, len, cpinfo, pseudo_header); } else { if (addr == 0) { /* * This must be some sort of LAPF on DLCI 0 for SVC * because DLCI 0 is reserved for LMI and SVC signaling * encapsulated in LAPF, and LMI is transmitted in * unnumbered information (03), so this must be LAPF * (guessing). * * XXX - but what is it? Is Q.933 carried inside UI * frames or other types of frames or both? */ return false; } if (fr_ctrl == (XDLC_U|XDLC_XID)) { /* * XID. */ return false; } /* * If the data does not start with unnumbered information (03) and * the DLCI# is not 0, then there may be Cisco Frame Relay encapsulation. */ return call_capture_dissector(chdlc_cap_handle, pd, offset, len, cpinfo, pseudo_header); } break; case GPRS_NS: return false; case RAW_ETHER: if (addr != 0) return call_capture_dissector(eth_cap_handle, pd, offset, len, cpinfo, pseudo_header); return false; } return false; } static void dissect_fr_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, bool has_direction, bool decode_address ) { int offset = 0; proto_item *ti = NULL; proto_tree *fr_tree = NULL; proto_tree *octet_tree = NULL; uint8_t fr_octet; bool is_response = false; uint32_t addr = 0; bool encap_is_frf_3_2; uint8_t fr_ctrl; uint16_t fr_type; int nlpid_offset; uint8_t fr_nlpid; int control; dissector_handle_t sub_dissector; tvbuff_t *next_tvb; col_set_str(pinfo->cinfo, COL_PROTOCOL, "FR"); col_clear(pinfo->cinfo, COL_INFO); if (has_direction) { if (pinfo->pseudo_header->dte_dce.flags & FROM_DCE) { col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE"); col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE"); } else { col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE"); col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE"); } } if (tree) { ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, -1, "Frame Relay"); fr_tree = proto_item_add_subtree(ti, ett_fr); } if (decode_address) { /* * OK, fetch the address field - keep going until we get an EA bit. */ fr_octet = tvb_get_uint8(tvb, offset); if (fr_octet & FRELAY_EA) { /* * Bogus! There should be at least 2 octets. * XXX - is this FRF.12 frame relay fragmentation? If so, we * should dissect it as such, if possible. */ addr = 0; proto_tree_add_expert_format(fr_tree, pinfo, &ei_fr_bogus_address, tvb, offset, 1, "Bogus 1-octet address field"); offset++; } else { static int * const first_address_bits[] = {&hf_fr_upper_dlci, &hf_fr_cr, &hf_fr_ea, NULL}; static int * const second_address_bits[] = {&hf_fr_second_dlci, &hf_fr_fecn, &hf_fr_becn, &hf_fr_de, &hf_fr_ea, NULL}; static int * const third_address_bits[] = {&hf_fr_third_dlci, &hf_fr_ea, NULL}; /* * The first octet contains the upper 6 bits of the DLCI, as well * as the C/R bit. */ addr = (fr_octet & FRELAY_UPPER_DLCI) >> 2; is_response = (fr_octet & FRELAY_CR); proto_tree_add_bitmask(fr_tree, tvb, offset, hf_fr_first_addr_octet, ett_fr_address, first_address_bits, ENC_NA); offset++; /* * The second octet contains 4 more bits of DLCI, as well as FECN, * BECN, and DE. */ fr_octet = tvb_get_uint8(tvb, offset); addr = (addr << 4) | ((fr_octet & FRELAY_SECOND_DLCI) >> 4); proto_tree_add_bitmask(fr_tree, tvb, offset, hf_fr_second_addr_octet, ett_fr_address, second_address_bits, ENC_NA); offset++; if (!(fr_octet & FRELAY_EA)) { /* * We have 3 or more address octets. * * The third octet contains 7 more bits of DLCI if EA isn't set, * and lower DLCI or DL-CORE control plus the DLCI or DL-CORE * control indicator flag if EA is set. */ fr_octet = tvb_get_uint8(tvb, offset); if (!(fr_octet & FRELAY_EA)) { /* * 7 more bits of DLCI. */ addr = (addr << 7) | ((fr_octet & FRELAY_THIRD_DLCI) >> 1); proto_tree_add_bitmask(fr_tree, tvb, offset, hf_fr_third_addr_octet, ett_fr_address, third_address_bits, ENC_NA); offset++; fr_octet = tvb_get_uint8(tvb, offset); while (!(fr_octet & FRELAY_EA)) { /* * Bogus! More than 4 octets of address. */ proto_tree_add_expert_format(fr_tree, pinfo, &ei_fr_bogus_address, tvb, offset, 1, "Bogus extra address octet"); offset++; fr_octet = tvb_get_uint8(tvb, offset); } } octet_tree = proto_tree_add_subtree_format(fr_tree, tvb, offset, 1, ett_fr_address, NULL, "Final address octet: 0x%02x", fr_octet); /* * Last octet - contains lower DLCI or DL-CORE control, DLCI or * DL-CORE control indicator flag. */ if (fr_octet & FRELAY_DC) { /* * DL-CORE. */ proto_tree_add_uint(octet_tree, hf_fr_dlcore_control, tvb, offset, 1, fr_octet); } else { /* * Last 6 bits of DLCI. */ addr = (addr << 6) | ((fr_octet & FRELAY_LOWER_DLCI) >> 2); proto_tree_add_uint(octet_tree, hf_fr_lower_dlci, tvb, offset, 1, fr_octet); } proto_tree_add_boolean(octet_tree, hf_fr_dc, tvb, offset, 1, fr_octet); proto_tree_add_boolean(octet_tree, hf_fr_ea, tvb, offset, 1, fr_octet); offset++; } } if (tree) { /* Put the full DLCI into the protocol tree. */ proto_tree_add_uint(fr_tree, hf_fr_dlci, tvb, 0, offset, addr); } conversation_set_elements_by_id(pinfo, CONVERSATION_DLCI, addr); col_add_fstr(pinfo->cinfo, COL_INFO, "DLCI %u", addr); } switch (fr_encap) { case FRF_3_2: encap_is_frf_3_2 = false; fr_ctrl = tvb_get_uint8(tvb, offset); if (fr_ctrl == XDLC_U) { /* * It looks like an RFC 2427-encapsulation frame, with the * default UI control field. */ encap_is_frf_3_2 = true; } else { if (addr == 0) { /* * This must be some sort of LAPF on DLCI 0 for SVC * because DLCI 0 is reserved for LMI and SVC signaling * encapsulated in LAPF, and LMI is transmitted in * unnumbered information (03), so this must be LAPF * (guessing). * * XXX - but what is it? Is Q.933 carried inside UI * frames or other types of frames or both? */ dissect_xdlc_control(tvb, offset, pinfo, fr_tree, hf_fr_control, ett_fr_control, &fr_cf_items, &fr_cf_items_ext, NULL, NULL, is_response, true, true); dissect_lapf(tvb_new_subset_remaining(tvb,offset),pinfo,tree); return; } if (fr_ctrl == (XDLC_U|XDLC_XID)) { /* * It looks like an RFC 2427-encapsulation frame, with the * a UI control field and an XID command. */ dissect_xdlc_control(tvb, offset, pinfo, fr_tree, hf_fr_control, ett_fr_control, &fr_cf_items, &fr_cf_items_ext, NULL, NULL, is_response, true, true); dissect_fr_xid(tvb_new_subset_remaining(tvb,offset),pinfo,tree); return; } /* * If the data does not start with unnumbered information (03) and * the DLCI# is not 0, then there may be Cisco Frame Relay encapsulation. * See if, were we to treat the two octets after the DLCI as a Cisco * HDLC type, we have a dissector for it. */ if (tvb_bytes_exist(tvb, offset, 2)) { fr_type = tvb_get_ntohs(tvb, offset); sub_dissector = dissector_get_uint_handle(chdlc_subdissector_table, fr_type); if (sub_dissector != NULL) { /* We have a dissector, so assume it's Cisco encapsulation. */ if (ti != NULL) { /* Include the Cisco HDLC type in the top-level protocol tree item. */ proto_item_set_end(ti, tvb, offset+2); } chdlctype(sub_dissector, fr_type, tvb, offset+2, pinfo, tree, fr_tree, hf_fr_chdlctype); return; } /* * We don't have a dissector; this might be an RFC 2427-encapsulated * See if we have a dissector for the putative NLPID. */ nlpid_offset = offset; control = tvb_get_uint8(tvb, nlpid_offset); if (control == 0) { /* Presumably a padding octet; the NLPID would be in the next octet. */ nlpid_offset++; control = tvb_get_uint8(tvb, nlpid_offset); } switch (control & 0x03) { case XDLC_S: /* * Supervisory frame. * We assume we're in extended mode, with 2-octet supervisory * control fields. */ nlpid_offset += 2; break; case XDLC_U: /* * Unnumbered frame. * * XXX - one octet or 2 in extended mode? */ nlpid_offset++; break; default: /* * Information frame. * We assume we're in extended mode, with 2-octet supervisory * control fields. */ nlpid_offset += 2; break; } if (tvb_bytes_exist(tvb, nlpid_offset, 1)) { fr_nlpid = tvb_get_uint8(tvb, nlpid_offset); sub_dissector = dissector_get_uint_handle(fr_osinl_subdissector_table, fr_nlpid); if (sub_dissector != NULL) encap_is_frf_3_2 = true; else { sub_dissector = dissector_get_uint_handle(osinl_incl_subdissector_table, fr_nlpid); if (sub_dissector != NULL) encap_is_frf_3_2 = true; else { if (fr_nlpid == NLPID_SNAP) encap_is_frf_3_2 = true; else { sub_dissector = dissector_get_uint_handle(fr_subdissector_table, fr_nlpid); if (sub_dissector != NULL) encap_is_frf_3_2 = true; } } } } } } if (encap_is_frf_3_2) { /* * We appear to have an NLPID for this dissector, so dissect * it as RFC 2427. */ control = dissect_xdlc_control(tvb, offset, pinfo, fr_tree, hf_fr_control, ett_fr_control, &fr_cf_items, &fr_cf_items_ext, NULL, NULL, is_response, true, true); offset += XDLC_CONTROL_LEN(control, true); /* * XXX - treat DLCI 0 specially? On DLCI 0, an NLPID of 0x08 * means Q.933, but on other circuits it could be the "for * protocols which do not have an NLPID assigned or do not * have a SNAP encapsulation" stuff from RFC 2427. */ dissect_fr_nlpid(tvb, offset, pinfo, tree, ti, fr_tree, fr_ctrl); } else { /* * See if it looks like raw Ethernet. */ uint16_t type_length; if (tvb_bytes_exist(tvb, offset + 12, 2) && ((type_length = tvb_get_ntohs(tvb, offset + 12)) <= IEEE_802_3_MAX_LEN || dissector_get_uint_handle(ethertype_subdissector_table, type_length) != NULL)) { /* It looks like a length or is a known Ethertype; dissect as raw Etheret */ next_tvb = tvb_new_subset_remaining(tvb, offset); call_dissector(eth_withfcs_handle, next_tvb, pinfo, tree); return; } else { /* It doesn't - just dissect it as data. */ next_tvb = tvb_new_subset_remaining(tvb, offset); call_data_dissector(next_tvb, pinfo, tree); } } break; case GPRS_NS: if (addr == 0) { fr_ctrl = tvb_get_uint8(tvb, offset); control = dissect_xdlc_control(tvb, offset, pinfo, fr_tree, hf_fr_control, ett_fr_control, &fr_cf_items, &fr_cf_items_ext, NULL, NULL, is_response, true, true); offset += XDLC_CONTROL_LEN(control, true); dissect_fr_nlpid(tvb, offset, pinfo, tree, ti, fr_tree, fr_ctrl); } else { next_tvb = tvb_new_subset_remaining(tvb, offset); call_dissector(gprs_ns_handle, next_tvb, pinfo, tree); } break; case RAW_ETHER: next_tvb = tvb_new_subset_remaining(tvb, offset); if (addr != 0) call_dissector(eth_withfcs_handle, next_tvb, pinfo, tree); else dissect_lapf(next_tvb, pinfo, tree); break; case LAPB: next_tvb = tvb_new_subset_remaining(tvb, offset); if (addr != 0) call_dissector(lapb_handle, next_tvb, pinfo, tree); else dissect_lapf(next_tvb, pinfo, tree); break; } } static int dissect_fr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { dissect_fr_common(tvb, pinfo, tree, false, true ); return tvb_captured_length(tvb); } static int dissect_fr_phdr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { dissect_fr_common(tvb, pinfo, tree, true, true ); return tvb_captured_length(tvb); } static int dissect_fr_stripped_address(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { dissect_fr_common(tvb, pinfo, tree, true, false ); return tvb_captured_length(tvb); } static int dissect_fr_uncompressed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_item *ti; proto_tree *fr_tree; col_set_str(pinfo->cinfo, COL_PROTOCOL, "FR"); col_clear(pinfo->cinfo, COL_INFO); ti = proto_tree_add_protocol_format(tree, proto_fr, tvb, 0, -1, "Frame Relay"); fr_tree = proto_item_add_subtree(ti, ett_fr); dissect_fr_nlpid(tvb, 0, pinfo, tree, ti, fr_tree, XDLC_U); return tvb_captured_length(tvb); } static void dissect_fr_nlpid(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, proto_item *ti, proto_tree *fr_tree, uint8_t fr_ctrl) { uint8_t fr_nlpid; tvbuff_t *next_tvb; /* * Tentatively set the Frame Relay item not to include the NLPID, * as OSI network layer protocols consider it to be part of * the OSI PDU. */ proto_item_set_end(ti, tvb, offset); fr_nlpid = tvb_get_uint8 (tvb,offset); if (fr_nlpid == 0) { proto_tree_add_uint_format(fr_tree, hf_fr_nlpid, tvb, offset, 1, fr_nlpid, "Padding"); offset++; if (ti != NULL) { /* Include the padding in the top-level protocol tree item. */ proto_item_set_end(ti, tvb, offset); } fr_nlpid=tvb_get_uint8( tvb,offset); } /* * OSI network layer protocols consider the NLPID to be part * of the frame, so we'll pass it as part of the payload and, * if the protocol is one of those, add it as a hidden item here. * We check both the generic OSI NLPID dissector table and * the Frame Relay OSI NLPID dissector table - the latter is for * NLPID's such as 0x08, which is Q.933 in Frame Relay but * other protocols (e.g., Q.931) on other network layers. * * "OSI network layer protocols" includes Q.933. * * We check the Frame Relay table first, so that protocols for which * the NLPID means something different on Frame Relay, i.e. Q.933 vs. * Q.931, are handled appropriately for Frame Relay. * * XXX - note that an NLPID of 0x08 for Q.933 could either be a * Q.933 signaling message or a message for a protocol * identified by a 2-octet layer 2 protocol type and a * 2-octet layer 3 protocol type, those protocol type * octets having the values from octets 6, 6a, 7, and 7a * of a Q.931 low layer compatibility information element * (section 4.5.19 of Q.931; Q.933 says they have the values * from a Q.933 low layer compatibility information element, * but Q.933 low layer compatibility information elements * don't have protocol values in them). * * Assuming that, as Q.933 seems to imply, that Q.933 messages * look just like Q.931 messages except where it explicitly * says they differ, then the octet after the NLPID would, * in a Q.933 message, have its upper 4 bits zero (that's * the length of the call reference value, in Q.931, and * is limited to 15 or fewer octets). As appears to be the case, * octet 6 of a Q.931 low layer compatibility element has the * 0x40 bit set, so you can distinguish between a Q.933 * message and an encapsulated packet by checking whether * the upper 4 bits of the octet after the NLPID are zero. * * Either that, or it's Q.933 iff the DLCI is 0. */ next_tvb = tvb_new_subset_remaining(tvb,offset); if (dissector_try_uint(fr_osinl_subdissector_table, fr_nlpid, next_tvb, pinfo, tree) || dissector_try_uint(osinl_incl_subdissector_table, fr_nlpid, next_tvb, pinfo, tree)) { /* * Yes, we got a match. Add the NLPID as a hidden item, * so you can, at least, filter on it. */ if (tree) { proto_item *hidden_item; hidden_item = proto_tree_add_uint(fr_tree, hf_fr_nlpid, tvb, offset, 1, fr_nlpid ); proto_item_set_hidden(hidden_item); } return; } /* * All other protocols don't. * * XXX - what about Cisco/Gang-of-Four LMI? Is the 0x09 considered * to be part of the LMI PDU? */ if (tree) proto_tree_add_uint(fr_tree, hf_fr_nlpid, tvb, offset, 1, fr_nlpid ); offset++; switch (fr_nlpid) { case NLPID_SNAP: if (ti != NULL) { /* Include the NLPID and SNAP header in the top-level protocol tree item. */ proto_item_set_end(ti, tvb, offset+5); } dissect_snap(tvb, offset, pinfo, tree, fr_tree, fr_ctrl, hf_fr_oui, hf_fr_snaptype, hf_fr_pid, 0); return; default: if (ti != NULL) { /* Include the NLPID in the top-level protocol tree item. */ proto_item_set_end(ti, tvb, offset); } next_tvb = tvb_new_subset_remaining(tvb,offset); if (!dissector_try_uint(fr_subdissector_table,fr_nlpid, next_tvb, pinfo, tree)) call_dissector(data_handle,next_tvb, pinfo, tree); break; } } static void dissect_lapf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_tree_add_expert(tree, pinfo, &ei_fr_frame_relay_lapf, tvb, 0, 0); call_dissector(data_handle,tvb_new_subset_remaining(tvb,0),pinfo,tree); } static void dissect_fr_xid(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_tree_add_expert(tree, pinfo, &ei_fr_frame_relay_xid, tvb, 0, 0); call_dissector(data_handle,tvb_new_subset_remaining(tvb,0),pinfo,tree); } /* Register the protocol with Wireshark */ void proto_register_fr(void) { static hf_register_info hf[] = { { &hf_fr_ea, { "EA", "fr.ea", FT_BOOLEAN, 8, TFS(&ea_string), FRELAY_EA, "Extended Address", HFILL }}, { &hf_fr_upper_dlci, { "Upper DLCI", "fr.upper_dlci", FT_UINT8, BASE_HEX, NULL, FRELAY_UPPER_DLCI, "Upper bits of DLCI", HFILL }}, { &hf_fr_cr, { "CR", "fr.cr", FT_BOOLEAN, 8, TFS(&tfs_command_response), FRELAY_CR, "Command/Response", HFILL }}, { &hf_fr_second_dlci, { "Second DLCI", "fr.second_dlci", FT_UINT8, BASE_HEX, NULL, FRELAY_SECOND_DLCI, "Bits below upper bits of DLCI", HFILL }}, { &hf_fr_fecn, { "FECN", "fr.fecn", FT_BOOLEAN, 8, NULL, FRELAY_FECN, "Forward Explicit Congestion Notification", HFILL }}, { &hf_fr_becn, { "BECN", "fr.becn", FT_BOOLEAN, 8, NULL, FRELAY_BECN, "Backward Explicit Congestion Notification", HFILL }}, { &hf_fr_de, { "DE", "fr.de", FT_BOOLEAN, 8, NULL, FRELAY_DE, "Discard Eligibility", HFILL }}, { &hf_fr_third_dlci, { "Third DLCI", "fr.third_dlci", FT_UINT8, BASE_HEX, NULL, FRELAY_THIRD_DLCI, "Additional bits of DLCI", HFILL }}, { &hf_fr_dlcore_control, { "DL-CORE Control", "fr.dlcore_control", FT_UINT8, BASE_HEX, NULL, FRELAY_LOWER_DLCI, "DL-Core control bits", HFILL }}, { &hf_fr_lower_dlci, { "Lower DLCI", "fr.lower_dlci", FT_UINT8, BASE_HEX, NULL, FRELAY_LOWER_DLCI, "Lower bits of DLCI", HFILL }}, { &hf_fr_dc, { "DC", "fr.dc", FT_BOOLEAN, 8, TFS(&ctrl_string), FRELAY_DC, "Address/Control", HFILL }}, { &hf_fr_dlci, { "DLCI", "fr.dlci", FT_UINT32, BASE_DEC, NULL, 0x0, "Data-Link Connection Identifier", HFILL }}, { &hf_fr_control, { "Control Field", "fr.control", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_fr_n_r, { "N(R)", "fr.control.n_r", FT_UINT16, BASE_DEC, NULL, XDLC_N_R_EXT_MASK, NULL, HFILL }}, { &hf_fr_n_s, { "N(S)", "fr.control.n_s", FT_UINT16, BASE_DEC, NULL, XDLC_N_S_EXT_MASK, NULL, HFILL }}, { &hf_fr_p, { "Poll", "fr.control.p", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_fr_p_ext, { "Poll", "fr.control.p", FT_BOOLEAN, 16, TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }}, { &hf_fr_f, { "Final", "fr.control.f", FT_BOOLEAN, 8, TFS(&tfs_set_notset), XDLC_P_F, NULL, HFILL }}, { &hf_fr_f_ext, { "Final", "fr.control.f", FT_BOOLEAN, 16, TFS(&tfs_set_notset), XDLC_P_F_EXT, NULL, HFILL }}, { &hf_fr_s_ftype, { "Supervisory frame type", "fr.control.s_ftype", FT_UINT16, BASE_HEX, VALS(stype_vals), XDLC_S_FTYPE_MASK, NULL, HFILL }}, { &hf_fr_u_modifier_cmd, { "Command", "fr.control.u_modifier_cmd", FT_UINT8, BASE_HEX, VALS(modifier_vals_cmd), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_fr_u_modifier_resp, { "Response", "fr.control.u_modifier_resp", FT_UINT8, BASE_HEX, VALS(modifier_vals_resp), XDLC_U_MODIFIER_MASK, NULL, HFILL }}, { &hf_fr_ftype_i, { "Frame type", "fr.control.ftype", FT_UINT16, BASE_HEX, VALS(ftype_vals), XDLC_I_MASK, NULL, HFILL }}, { &hf_fr_ftype_s_u, { "Frame type", "fr.control.ftype", FT_UINT8, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }}, { &hf_fr_ftype_s_u_ext, { "Frame type", "fr.control.ftype", FT_UINT16, BASE_HEX, VALS(ftype_vals), XDLC_S_U_MASK, NULL, HFILL }}, { &hf_fr_nlpid, { "NLPID", "fr.nlpid", FT_UINT8, BASE_HEX, VALS(fr_nlpid_vals), 0x0, "Frame Relay Encapsulated Protocol NLPID", HFILL }}, { &hf_fr_oui, { "Organization Code", "fr.snap.oui", FT_UINT24, BASE_OUI, NULL, 0x0, NULL, HFILL }}, { &hf_fr_pid, { "Protocol ID", "fr.snap.pid", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_fr_snaptype, { "Type", "fr.snaptype", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, "Frame Relay SNAP Encapsulated Protocol", HFILL }}, { &hf_fr_chdlctype, { "Type", "fr.chdlctype", FT_UINT16, BASE_HEX, VALS(chdlc_vals), 0x0, "Frame Relay Cisco HDLC Encapsulated Protocol", HFILL }}, { &hf_fr_first_addr_octet, { "First address octet", "fr.first_addr_octet", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_fr_second_addr_octet, { "Second address octet", "fr.second_addr_octet", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_fr_third_addr_octet, { "Third address octet", "fr.third_addr_octet", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, }; /* Setup protocol subtree array */ static int *ett[] = { &ett_fr, &ett_fr_address, &ett_fr_control, }; static ei_register_info ei[] = { { &ei_fr_bogus_address, { "fr.bogus_address", PI_PROTOCOL, PI_WARN, "Bogus address", EXPFILL }}, { &ei_fr_frame_relay_lapf, { "fr.frame_relay.lapf", PI_UNDECODED, PI_WARN, "Frame relay lapf not yet implemented", EXPFILL }}, { &ei_fr_frame_relay_xid, { "fr.frame_relay.xid", PI_UNDECODED, PI_WARN, "Frame relay xid not yet implemented", EXPFILL }}, }; static const enum_val_t fr_encap_options[] = { { "frf-3.2", "FRF 3.2/Cisco HDLC", FRF_3_2 }, { "gprs-ns", "GPRS Network Service", GPRS_NS }, { "ethernet", "Raw Ethernet", RAW_ETHER }, { "lapb", "LAPB (T1.617a-1994 Annex G)", LAPB }, { NULL, NULL, 0 }, }; module_t *frencap_module; expert_module_t* expert_fr; proto_fr = proto_register_protocol("Frame Relay", "FR", "fr"); proto_register_field_array(proto_fr, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_fr = expert_register_protocol(proto_fr); expert_register_field_array(expert_fr, ei, array_length(ei)); fr_subdissector_table = register_dissector_table("fr.nlpid", "Frame Relay NLPID", proto_fr, FT_UINT8, BASE_HEX); fr_osinl_subdissector_table = register_dissector_table("fr.osinl", "Frame Relay OSI NLPID", proto_fr, FT_UINT8, BASE_HEX); register_dissector("fr_uncompressed", dissect_fr_uncompressed, proto_fr); fr_handle = register_dissector("fr", dissect_fr, proto_fr); register_dissector("fr_stripped_address", dissect_fr_stripped_address, proto_fr); frencap_module = prefs_register_protocol(proto_fr, NULL); /* * XXX - this should really be per-circuit - I've seen at least one * capture where different DLCIs have different encapsulations - but * we don't yet have any support for per-circuit encapsulations. * * Even with that, though, we might want a default encapsulation, * so that people dealing with GPRS can make gprs-ns the default. */ prefs_register_enum_preference(frencap_module, "encap", "Encapsulation", "Encapsulation", &fr_encap, fr_encap_options, false); register_capture_dissector_table("fr.nlpid", "Frame Relay NLPID"); } void proto_reg_handoff_fr(void) { dissector_handle_t fr_phdr_handle; capture_dissector_handle_t fr_cap_handle; dissector_add_uint("gre.proto", ETHERTYPE_RAW_FR, fr_handle); dissector_add_uint("wtap_encap", WTAP_ENCAP_FRELAY, fr_handle); dissector_add_uint("juniper.proto", JUNIPER_PROTO_FRELAY, fr_handle); dissector_add_uint("sflow_245.header_protocol", SFLOW_245_HEADER_FRAME_RELAY, fr_handle); dissector_add_uint("atm.aal5.type", TRAF_FR, fr_handle); dissector_add_uint("l2tp.pw_type", L2TPv3_PW_FR, fr_handle); dissector_add_uint("sll.hatype", ARPHRD_FRAD, fr_handle); fr_phdr_handle = create_dissector_handle(dissect_fr_phdr, proto_fr); dissector_add_uint("wtap_encap", WTAP_ENCAP_FRELAY_WITH_PHDR, fr_phdr_handle); fr_cap_handle = create_capture_dissector_handle(capture_fr, proto_fr); capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_FRELAY, fr_cap_handle); capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_FRELAY_WITH_PHDR, fr_cap_handle); eth_withfcs_handle = find_dissector_add_dependency("eth_withfcs", proto_fr); gprs_ns_handle = find_dissector_add_dependency("gprs_ns", proto_fr); lapb_handle = find_dissector_add_dependency("lapb", proto_fr); data_handle = find_dissector_add_dependency("data", proto_fr); chdlc_subdissector_table = find_dissector_table("chdlc.protocol"); osinl_incl_subdissector_table = find_dissector_table("osinl.incl"); ethertype_subdissector_table = find_dissector_table("ethertype"); chdlc_cap_handle = find_capture_dissector("chdlc"); eth_cap_handle = find_capture_dissector("eth"); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local Variables: * c-basic-offset: 2 * tab-width: 8 * indent-tabs-mode: nil * End: * * ex: set shiftwidth=2 tabstop=8 expandtab: * :indentSize=2:tabSize=8:noTabs=true: */