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wireshark/epan/dissectors/packet-rudp.c
Guy Harris e1d9a226a2 Fix the type of arrays of pointers to hf_ values for bitfield routines. 
The static arrays are supposed to be arrays of const pointers to int,
not arrays of non-const pointers to const int.

Fixing that means some bugs (scribbling on what's *supposed* to be a
const array) will be caught (see packet-ieee80211-radiotap.c for
examples, the first of which inspired this change and the second of
which was discovered while testing compiles with this change), and
removes the need for some annoying casts.

Also make some of those arrays static while we're at it.

Update documentation and dissector-generator tools.

Change-Id: I789da5fc60aadc15797cefecfd9a9fbe9a130ccc
Reviewed-on: https://code.wireshark.org/review/37517
Petri-Dish: Guy Harris <gharris@sonic.net>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
2020-06-19 11:32:26 +00:00

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