/* packet-mdshdr.c * Routines for dissection of Cisco MDS Switch Internal Header * Copyright 2001, Dinesh G Dutt * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include #include "packet-fc.h" void proto_register_mdshdr(void); void proto_reg_handoff_mdshdr(void); #define MDSHDR_VERSION_OFFSET 0 /* Mdshdr Control bits */ #define MDSHDR_CTL_IDXDIRECT 1 #define MDSHDR_CTL_IGNACLO 2 #define MDSHDR_CTL_DRP 4 /* OFFSETS OF FIELDS */ #define MDSHDR_VER_OFFSET 0 #define MDSHDR_SOF_OFFSET 1 #define MDSHDR_PKTLEN_OFFSET 2 #define MDSHDR_DIDX_OFFSET 5 #define MDSHDR_SIDX_OFFSET 6 #define MDSHDR_VSAN_OFFSET 13 /* Two size definitions are sufficient */ #define MDSHDR_SIZE_BYTE sizeof(char) #define MDSHDR_SIZE_INT16 sizeof(uint16_t) #define MDSHDR_SIZE_INT32 sizeof(uint32_t) /* Other miscellaneous defines; can't rely on sizeof structs */ #define MDSHDR_MAX_VERSION 0 #define MDSHDR_HEADER_SIZE 16 #define MDSHDR_TRAILER_SIZE 6 /* SOF Encodings */ #define MDSHDR_SOFc1 0x1 #define MDSHDR_SOFi1 0x2 #define MDSHDR_SOFn1 0x3 #define MDSHDR_SOFi2 0x4 #define MDSHDR_SOFn2 0x5 #define MDSHDR_SOFi3 0x6 #define MDSHDR_SOFn3 0x7 #define MDSHDR_SOFf 0x8 #define MDSHDR_SOFc4 0x9 #define MDSHDR_SOFi4 0xa #define MDSHDR_SOFn4 0xb /* EOF Encodings */ #define MDSHDR_EOFt 0x1 #define MDSHDR_EOFdt 0x2 #define MDSHDR_EOFa 0x4 #define MDSHDR_EOFn 0x3 #define MDSHDR_EOFdti 0x6 #define MDSHDR_EOFni 0x7 #define MDSHDR_EOFrt 0xa #define MDSHDR_EOFrti 0xe #define MDSHDR_EOF_UNKNOWN 0xb /* Initialize the protocol and registered fields */ static int proto_mdshdr; static int hf_mdshdr_sof; static int hf_mdshdr_pkt_len; static int hf_mdshdr_dstidx; static int hf_mdshdr_srcidx; static int hf_mdshdr_vsan; static int hf_mdshdr_eof; static int hf_mdshdr_no_trailer; static int hf_mdshdr_span; static int hf_mdshdr_fccrc; /* Initialize the subtree pointers */ static int ett_mdshdr; static int ett_mdshdr_hdr; static int ett_mdshdr_trlr; static dissector_handle_t mdshdr_handle; static dissector_handle_t fc_dissector_handle; static bool decode_if_zero_etype; static const value_string sof_vals[] = { {MDSHDR_SOFc1, "SOFc1"}, {MDSHDR_SOFi1, "SOFi1"}, {MDSHDR_SOFn1, "SOFn1"}, {MDSHDR_SOFi2, "SOFi2"}, {MDSHDR_SOFn2, "SOFn2"}, {MDSHDR_SOFi3, "SOFi3"}, {MDSHDR_SOFn3, "SOFn3"}, {MDSHDR_SOFc4, "SOFc4"}, {MDSHDR_SOFi4, "SOFi4"}, {MDSHDR_SOFn4, "SOFn4"}, {MDSHDR_SOFf, "SOFf"}, {0, NULL}, }; static const value_string eof_vals[] = { {MDSHDR_EOFt, "EOFt"}, {MDSHDR_EOFdt, "EOFdt"}, {MDSHDR_EOFa, "EOFa"}, {MDSHDR_EOFn, "EOFn"}, {MDSHDR_EOFdti, "EOFdti"}, {MDSHDR_EOFni, "EOFni"}, {MDSHDR_EOFrt, "EOFrt"}, {MDSHDR_EOFrti, "EOFrti"}, /*{MDSHDR_EOF_UNKNOWN, ""}, intentionally removed*/ {0, NULL}, }; static int dissect_mdshdr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { /* Set up structures needed to add the protocol subtree and manage it */ proto_item *ti_main; proto_item *hidden_item; proto_tree *mdshdr_tree_main, *mdshdr_tree_hdr, *mdshdr_tree_trlr; int offset = 0; unsigned pktlen; tvbuff_t *next_tvb; uint8_t sof, eof; int trailer_start = 0; /*0 means "no trailer found"*/ fc_data_t fc_data; col_set_str(pinfo->cinfo, COL_PROTOCOL, "MDS Header"); col_clear(pinfo->cinfo, COL_INFO); sof = tvb_get_uint8(tvb, offset+MDSHDR_SOF_OFFSET) & 0x0F; pktlen = tvb_get_ntohs(tvb, offset+MDSHDR_PKTLEN_OFFSET) & 0x1FFF; /* The Mdshdr trailer is at the end of the frame */ if ((tvb_captured_length(tvb) >= (MDSHDR_HEADER_SIZE + pktlen)) /* Avoid header/trailer overlap if something wrong */ && (pktlen >= MDSHDR_TRAILER_SIZE)) { trailer_start = MDSHDR_HEADER_SIZE + pktlen - MDSHDR_TRAILER_SIZE; eof = tvb_get_uint8(tvb, trailer_start); tvb_set_reported_length(tvb, MDSHDR_HEADER_SIZE+pktlen); } else { eof = MDSHDR_EOF_UNKNOWN; } fc_data.sof_eof = 0; if ((sof == MDSHDR_SOFi3) || (sof == MDSHDR_SOFi2) || (sof == MDSHDR_SOFi1) || (sof == MDSHDR_SOFi4)) { fc_data.sof_eof = FC_DATA_SOF_FIRST_FRAME; } else if (sof == MDSHDR_SOFf) { fc_data.sof_eof = FC_DATA_SOF_SOFF; } if (eof != MDSHDR_EOFn) { fc_data.sof_eof |= FC_DATA_EOF_LAST_FRAME; } else if (eof != MDSHDR_EOFt) { fc_data.sof_eof |= FC_DATA_EOF_INVALID; } if (tree) { ti_main = proto_tree_add_protocol_format(tree, proto_mdshdr, tvb, 0, MDSHDR_HEADER_SIZE+pktlen, "MDS Header(%s/%s)", val_to_str(sof, sof_vals, "Unknown(%u)"), val_to_str(eof, eof_vals, "Unknown(%u)")); mdshdr_tree_main = proto_item_add_subtree(ti_main, ett_mdshdr); /* Add Header part as subtree first */ mdshdr_tree_hdr = proto_tree_add_subtree(mdshdr_tree_main, tvb, MDSHDR_VER_OFFSET, MDSHDR_HEADER_SIZE, ett_mdshdr_hdr, NULL, "MDS Header"); hidden_item = proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_sof, tvb, MDSHDR_SOF_OFFSET, MDSHDR_SIZE_BYTE, ENC_BIG_ENDIAN); proto_item_set_hidden(hidden_item); proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_pkt_len, tvb, MDSHDR_PKTLEN_OFFSET, MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN); proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_dstidx, tvb, MDSHDR_DIDX_OFFSET, MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN); proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_srcidx, tvb, MDSHDR_SIDX_OFFSET, MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN); proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_vsan, tvb, MDSHDR_VSAN_OFFSET, MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN); hidden_item = proto_tree_add_item(mdshdr_tree_hdr, hf_mdshdr_span, tvb, MDSHDR_VSAN_OFFSET, MDSHDR_SIZE_INT16, ENC_BIG_ENDIAN); proto_item_set_hidden(hidden_item); /* Add Mdshdr Trailer part */ if (tvb_reported_length(tvb) >= MDSHDR_HEADER_SIZE + pktlen && 0 != trailer_start) { mdshdr_tree_trlr = proto_tree_add_subtree(mdshdr_tree_main, tvb, trailer_start, MDSHDR_TRAILER_SIZE, ett_mdshdr_trlr, NULL, "MDS Trailer"); proto_tree_add_item(mdshdr_tree_trlr, hf_mdshdr_eof, tvb, trailer_start, MDSHDR_SIZE_BYTE, ENC_BIG_ENDIAN); proto_tree_add_item(mdshdr_tree_trlr, hf_mdshdr_fccrc, tvb, trailer_start+2, MDSHDR_SIZE_INT32, ENC_BIG_ENDIAN); } else { proto_tree_add_item(mdshdr_tree_main, hf_mdshdr_no_trailer, tvb, 0, 0, ENC_NA); } } if (tvb_reported_length(tvb) >= MDSHDR_HEADER_SIZE + pktlen && 0 != pktlen /*if something wrong*/) { next_tvb = tvb_new_subset_length(tvb, MDSHDR_HEADER_SIZE, pktlen); /* XXX what to do with the rest of this frame? --ArtemTamazov */ } else { next_tvb = tvb_new_subset_remaining(tvb, MDSHDR_HEADER_SIZE); } /* Call the Fibre Channel dissector */ if (fc_dissector_handle) { fc_data.ethertype = ETHERTYPE_FCFT; call_dissector_with_data(fc_dissector_handle, next_tvb, pinfo, tree, &fc_data); } else { call_data_dissector(next_tvb, pinfo, tree); } return tvb_captured_length(tvb); } void proto_register_mdshdr(void) { static hf_register_info hf[] = { { &hf_mdshdr_sof, {"SOF", "mdshdr.sof", FT_UINT8, BASE_DEC, VALS(sof_vals), 0x0, NULL, HFILL}}, { &hf_mdshdr_pkt_len, {"Packet Len", "mdshdr.plen", FT_UINT16, BASE_DEC, NULL, 0x1FFF, NULL, HFILL}}, { &hf_mdshdr_dstidx, {"Dst Index", "mdshdr.dstidx", FT_UINT16, BASE_HEX, NULL, 0x0FFC, NULL, HFILL}}, { &hf_mdshdr_srcidx, {"Src Index", "mdshdr.srcidx", FT_UINT16, BASE_HEX, NULL, 0x03FF, NULL, HFILL}}, { &hf_mdshdr_vsan, {"VSAN", "mdshdr.vsan", FT_UINT16, BASE_DEC, NULL, 0x0FFF, NULL, HFILL}}, { &hf_mdshdr_eof, {"EOF", "mdshdr.eof", FT_UINT8, BASE_DEC, VALS(eof_vals), 0x0, NULL, HFILL}}, { &hf_mdshdr_no_trailer, {"MDS Trailer: Not Found", "mdshdr.no_trailer", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL}}, { &hf_mdshdr_span, {"SPAN Frame", "mdshdr.span", FT_UINT16, BASE_DEC, NULL, 0xF000, NULL, HFILL}}, { &hf_mdshdr_fccrc, {"CRC", "mdshdr.crc", FT_UINT32, BASE_HEX, NULL, 0x0, NULL, HFILL}}, }; /* Setup protocol subtree array */ static int *ett[] = { &ett_mdshdr, &ett_mdshdr_hdr, &ett_mdshdr_trlr }; module_t *mdshdr_module; /* Register the protocol name and description */ proto_mdshdr = proto_register_protocol("MDS Header", "MDS Header", "mdshdr"); proto_register_field_array(proto_mdshdr, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); mdshdr_module = prefs_register_protocol(proto_mdshdr, proto_reg_handoff_mdshdr); prefs_register_bool_preference(mdshdr_module, "decode_if_etype_zero", "Decode as MDS Header if Ethertype == 0", "A frame is considered for decoding as MDSHDR if either " "ethertype is 0xFCFC or zero. Turn this flag off if you " "don't want ethertype zero to be decoded as MDSHDR. " "This might be useful to avoid problems with test frames.", &decode_if_zero_etype); /* Register the dissector */ mdshdr_handle = register_dissector("mdshdr", dissect_mdshdr, proto_mdshdr); } void proto_reg_handoff_mdshdr(void) { static bool registered_for_zero_etype = false; static bool mdshdr_prefs_initialized = false; if (!mdshdr_prefs_initialized) { /* * This is the first time this has been called (i.e., * Wireshark/TShark is starting up), so create a handle for * the MDS Header dissector, register the dissector for * ethertype ETHERTYPE_FCFT, and fetch the data and Fibre * Channel handles. */ dissector_add_uint("ethertype", ETHERTYPE_FCFT, mdshdr_handle); fc_dissector_handle = find_dissector_add_dependency("fc", proto_mdshdr); mdshdr_prefs_initialized = true; } /* * Only register the dissector for ethertype 0 if the preference * is set to do so. */ if (decode_if_zero_etype) { /* * The preference to register for ethertype ETHERTYPE_UNK (0) * is set; if we're not registered for ethertype ETHERTYPE_UNK, * do so. */ if (!registered_for_zero_etype) { dissector_add_uint("ethertype", ETHERTYPE_UNK, mdshdr_handle); registered_for_zero_etype = true; } } else { /* * The preference to register for ethertype ETHERTYPE_UNK (0) * is not set; if we're registered for ethertype ETHERTYPE_UNK, * undo that registration. */ if (registered_for_zero_etype) { dissector_delete_uint("ethertype", ETHERTYPE_UNK, mdshdr_handle); registered_for_zero_etype = false; } } } /* * 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: */