/* packet-prp.c * Routines for PRP (Parallel Redundancy Protocol; IEC62439 Part 3) dissection * Copyright 2007, Sven Meier * Copyright 2011, Martin Renold * Copyright 2011, Florian Reichert * * 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 PRP_LAN_A 10 #define PRP_LAN_B 11 static const value_string prp_lan_vals[] = { {PRP_LAN_A, "LAN A"}, {PRP_LAN_B, "LAN B"}, {0, NULL} }; /**********************************************************/ /* Initialize the protocol and registered fields */ /**********************************************************/ void proto_register_prp(void); void proto_reg_handoff_prp(void); static int proto_prp = -1; /* Initialize trailer fields */ static int hf_prp_redundancy_control_trailer_sequence_nr = -1; static int hf_prp_redundancy_control_trailer_lan = -1; static int hf_prp_redundancy_control_trailer_size = -1; static int hf_prp_redundancy_control_trailer_suffix = -1; static int hf_prp_redundancy_control_trailer_version = -1; /* Initialize the subtree pointers */ static gint ett_prp_redundancy_control_trailer = -1; /* Post dissectors (such as the trailer dissector for this protocol) * get called for every single frame anyone loads into Wireshark. * Since this protocol is not of general interest we disable this * protocol by default. * * This is done separately from the disabled protocols list mainly so * we can disable it by default. XXX Maybe there's a better way. */ static gboolean prp_enable_dissector = FALSE; /* Code to actually dissect the packets */ static int dissect_prp_redundancy_control_trailer(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void* data _U_) { proto_item *ti; proto_tree *prp_tree; guint i; guint length; guint offset; guint16 lan_id; guint16 lsdu_size; guint16 prp1_suffix; guint trailer_start; guint trailer_length; trailer_start = 0; trailer_length = 0; length = tvb_reported_length(tvb); if(length < 14) return 0; if(ETHERTYPE_VLAN == tvb_get_ntohs(tvb, 12)) /* tagged frame */ { offset = 18; } else /* untagged */ { offset = 14; } if (!tree) return tvb_captured_length(tvb); /* search for PRP-0 trailer */ /* If the frame is > 64 bytes, the PRP-0 trailer is always at the end. */ /* If the frame is <= 64 bytes, the PRP-0 trailer may be anywhere (before the padding) */ for(i=length-4; i>=offset; i--) { lan_id = tvb_get_ntohs(tvb, (i+2)) >> 12; lsdu_size = tvb_get_ntohs(tvb, (i+2)) & 0x0fff; if(lsdu_size == i+4-offset && (lan_id == 0xa || lan_id == 0xb)) { trailer_start = i; trailer_length = 4; break; } if (length > 64) { break; /* don't search, just check the last position */ } } /* check for PRP-1 trailer */ /* PRP-1 trailer is always at the end of the frame, after any padding. */ { lan_id = tvb_get_ntohs(tvb, length-4) >> 12; lsdu_size = tvb_get_ntohs(tvb, length-4) & 0x0fff; prp1_suffix = tvb_get_ntohs(tvb, length-2); if(prp1_suffix == ETHERTYPE_PRP && (lan_id == 0xa || lan_id == 0xb)) { /* We don't check the lsdu_size, we just display whether it's correct. Helpful for testing, because different definitions of the lsdu_size did exist. */ trailer_start = length-6; trailer_length = 6; } } if(trailer_length != 0) { /* create display subtree for the protocol */ ti = proto_tree_add_item(tree, proto_prp, tvb, trailer_start, trailer_length, ENC_NA); prp_tree = proto_item_add_subtree(ti, ett_prp_redundancy_control_trailer); if (trailer_length == 4) { ti = proto_tree_add_string(prp_tree, hf_prp_redundancy_control_trailer_version, tvb, trailer_start, trailer_length, "PRP-0"); } else { ti = proto_tree_add_string(prp_tree, hf_prp_redundancy_control_trailer_version, tvb, trailer_start, trailer_length, "PRP-1"); } PROTO_ITEM_SET_GENERATED(ti); proto_tree_add_item(prp_tree, hf_prp_redundancy_control_trailer_sequence_nr, tvb, trailer_start, 2, ENC_BIG_ENDIAN); proto_tree_add_item(prp_tree, hf_prp_redundancy_control_trailer_lan, tvb, trailer_start+2, 2, ENC_BIG_ENDIAN); if (trailer_length == 4) { /* PRP-0 */ proto_tree_add_item(prp_tree, hf_prp_redundancy_control_trailer_size, tvb, trailer_start+2, 2, ENC_BIG_ENDIAN); } else { /* PRP-1 */ int lsdu_size_correct = length-offset; if (lsdu_size == lsdu_size_correct) { proto_tree_add_uint_format(prp_tree, hf_prp_redundancy_control_trailer_size, tvb, trailer_start+2, 2, lsdu_size, "LSDU size: %d [correct]", lsdu_size); } else { proto_tree_add_uint_format(prp_tree, hf_prp_redundancy_control_trailer_size, tvb, trailer_start+2, 2, lsdu_size, "LSDU size: %d [WRONG, should be %d]", lsdu_size, lsdu_size_correct); } /* suffix */ proto_tree_add_item(prp_tree, hf_prp_redundancy_control_trailer_suffix, tvb, trailer_start+4, 2, ENC_BIG_ENDIAN); } } return tvb_captured_length(tvb); } /* Register the protocol with Wireshark */ void proto_register_prp(void) { static hf_register_info hf[] = { /*trailer*/ { &hf_prp_redundancy_control_trailer_sequence_nr, { "Sequence number", "prp.trailer.prp_sequence_nr", FT_UINT16, BASE_DEC, NULL, 0x00, NULL, HFILL } }, { &hf_prp_redundancy_control_trailer_lan, { "LAN", "prp.trailer.prp_lan", FT_UINT16, BASE_DEC, VALS(prp_lan_vals), 0xf000, NULL, HFILL } }, { &hf_prp_redundancy_control_trailer_size, { "Size", "prp.trailer.prp_size", FT_UINT16, BASE_DEC, NULL, 0x0fff, NULL, HFILL } }, { &hf_prp_redundancy_control_trailer_suffix, { "Suffix", "prp.trailer.prp1_suffix", FT_UINT16, BASE_HEX, NULL, 0x00, NULL, HFILL } }, { &hf_prp_redundancy_control_trailer_version, { "PRP Version", "prp.trailer.version", FT_STRING, BASE_NONE, NULL, 0x00, NULL, HFILL } } }; static gint *ett[] = { &ett_prp_redundancy_control_trailer, }; module_t *prp_module; /* Register the protocol name and description */ proto_prp = proto_register_protocol("Parallel Redundancy Protocol (IEC62439 Part 3)", "PRP", "prp"); prp_module = prefs_register_protocol(proto_prp, proto_reg_handoff_prp); prefs_register_bool_preference(prp_module, "enable", "Enable dissector", "Enable this dissector (default is false)", &prp_enable_dissector); /* Required function calls to register the header fields and subtree used */ proto_register_field_array(proto_prp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_prp(void) { static gboolean prefs_initialized = FALSE; if (!prefs_initialized) { dissector_handle_t prp_redundancy_control_trailer_handle; prp_redundancy_control_trailer_handle = create_dissector_handle(dissect_prp_redundancy_control_trailer, proto_prp); register_postdissector(prp_redundancy_control_trailer_handle); prefs_initialized = TRUE; } proto_set_decoding(proto_prp, prp_enable_dissector); } /* * Editor modelines - http://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: */