230 lines
6.0 KiB
C
230 lines
6.0 KiB
C
/* packet-rudp.c
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* Routines for Reliable UDP Protocol.
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* Copyright 2004, Duncan Sargeant <dunc-ethereal@rcpt.to>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-data.c, README.developer, and various other files.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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* Reliable UDP is a lightweight protocol for providing TCP-like flow
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* control over UDP. Cisco published an PFC a long time ago, and
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* their actual implementation is slightly different, having no
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* checksum field.
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*
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* I've cheated here - RUDP could be used for anything, but I've only
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* seen it used to switched telephony calls, so we just call the Cisco SM
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* dissector from here.
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*
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* Here are some links:
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*
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* http://www.watersprings.org/pub/id/draft-ietf-sigtran-reliable-udp-00.txt
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* http://www.javvin.com/protocolRUDP.html
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* http://www.cisco.com/univercd/cc/td/doc/product/access/sc/rel7/omts/omts_apb.htm#30052
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*/
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#include "config.h"
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#include <epan/packet.h>
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void proto_register_rudp(void);
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void proto_reg_handoff_rudp(void);
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static int proto_rudp = -1;
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static int hf_rudp_flags = -1;
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static int hf_rudp_flags_syn = -1;
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static int hf_rudp_flags_ack = -1;
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static int hf_rudp_flags_eak = -1;
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static int hf_rudp_flags_rst = -1;
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static int hf_rudp_flags_nul = -1;
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static int hf_rudp_flags_chk = -1;
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static int hf_rudp_flags_tcs = -1;
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static int hf_rudp_flags_0 = -1;
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static int hf_rudp_hlen = -1;
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static int hf_rudp_seq = -1;
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static int hf_rudp_ack = -1;
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static int hf_rudp_cksum = -1;
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static gint ett_rudp = -1;
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static gint ett_rudp_flags = -1;
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static dissector_handle_t sm_handle = NULL;
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static int
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dissect_rudp(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree, void* data _U_)
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{
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tvbuff_t * next_tvb;
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proto_tree *rudp_tree;
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proto_item *ti;
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guint8 hlen;
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static int * const flags[] = {
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&hf_rudp_flags_syn,
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&hf_rudp_flags_ack,
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&hf_rudp_flags_eak,
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&hf_rudp_flags_rst,
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&hf_rudp_flags_nul,
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&hf_rudp_flags_chk,
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&hf_rudp_flags_tcs,
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&hf_rudp_flags_0,
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NULL
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};
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hlen = tvb_get_guint8(tvb, 1);
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "RUDP");
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col_clear(pinfo->cinfo, COL_INFO);
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ti = proto_tree_add_item(tree, proto_rudp, tvb, 0, hlen, ENC_NA);
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rudp_tree = proto_item_add_subtree(ti, ett_rudp);
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proto_tree_add_bitmask(rudp_tree, tvb, 0, hf_rudp_flags, ett_rudp_flags, flags, ENC_BIG_ENDIAN);
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proto_tree_add_item(rudp_tree, hf_rudp_hlen, tvb, 1, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(rudp_tree, hf_rudp_seq, tvb, 2, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(rudp_tree, hf_rudp_ack, tvb, 3, 1, ENC_BIG_ENDIAN);
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/* If the header is more than 4 bytes the next 2 bytes are the checksum */
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if (hlen > 4) {
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proto_tree_add_checksum(rudp_tree, tvb, 4, hf_rudp_cksum, -1, NULL, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
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}
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/* If we have even more bytes their meaning is unknown - we have seen this
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* in live captures */
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if (hlen > 6) {
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next_tvb = tvb_new_subset_length(tvb, 6, hlen-6);
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call_data_dissector(next_tvb, pinfo, rudp_tree);
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}
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next_tvb = tvb_new_subset_remaining(tvb, hlen);
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if (tvb_captured_length(next_tvb) && sm_handle)
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call_dissector(sm_handle, next_tvb, pinfo, tree);
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return tvb_captured_length(tvb);
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}
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void
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proto_register_rudp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_rudp_flags,
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{ "RUDP Header flags", "rudp.flags",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_rudp_flags_syn,
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{ "Syn", "rudp.flags.syn",
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FT_BOOLEAN, 8, NULL, 0x80,
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NULL, HFILL }
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},
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{ &hf_rudp_flags_ack,
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{ "Ack", "rudp.flags.ack",
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FT_BOOLEAN, 8, NULL, 0x40,
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NULL, HFILL }
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},
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{ &hf_rudp_flags_eak,
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{ "Eak", "rudp.flags.eak",
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FT_BOOLEAN, 8, NULL, 0x20,
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"Extended Ack", HFILL }
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},
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{ &hf_rudp_flags_rst,
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{ "RST", "rudp.flags.rst",
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FT_BOOLEAN, 8, NULL, 0x10,
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"Reset flag", HFILL }
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},
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{ &hf_rudp_flags_nul,
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{ "NULL", "rudp.flags.nul",
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FT_BOOLEAN, 8, NULL, 0x08,
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"Null flag", HFILL }
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},
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{ &hf_rudp_flags_chk,
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{ "CHK", "rudp.flags.chk",
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FT_BOOLEAN, 8, NULL, 0x04,
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"Checksum is on header or body", HFILL }
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},
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{ &hf_rudp_flags_tcs,
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{ "TCS", "rudp.flags.tcs",
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FT_BOOLEAN, 8, NULL, 0x02,
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"Transfer Connection System", HFILL }
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},
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{ &hf_rudp_flags_0,
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{ "0", "rudp.flags.0",
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FT_BOOLEAN, 8, NULL, 0x01,
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NULL, HFILL }
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},
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{ &hf_rudp_hlen,
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{ "Header Length", "rudp.hlen",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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NULL, HFILL }
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},
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{ &hf_rudp_seq,
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{ "Seq", "rudp.seq",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Sequence Number", HFILL }
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},
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{ &hf_rudp_ack,
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{ "Ack", "rudp.ack",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Acknowledgement Number", HFILL }
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},
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{ &hf_rudp_cksum,
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{ "Checksum", "rudp.cksum",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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NULL, HFILL }
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},
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_rudp,
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&ett_rudp_flags,
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};
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proto_rudp = proto_register_protocol ("Reliable UDP", "RUDP", "rudp");
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proto_register_field_array(proto_rudp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_rudp(void) {
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dissector_handle_t rudp_handle;
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/* Disable rudp by default. The previously hardcoded value of
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* 7000 (used by Cisco) collides with afs and as the draft states:
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* "RUDP doesn't place any restrictions on which UDP port numbers are used.
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* Valid port numbers are ports not defined in RFC 1700."
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*/
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/* FIXME: The proper solution would be to convert this dissector into
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* heuristic dissector, but it isn't complete anyway.
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*/
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rudp_handle = create_dissector_handle(dissect_rudp, proto_rudp);
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dissector_add_for_decode_as_with_preference("udp.port", rudp_handle);
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sm_handle = find_dissector_add_dependency("sm", proto_rudp);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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