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wireshark/epan/dissectors/packet-cesoeth.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

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/* packet-cesoeth.c
* Dissection of Circuit Emulation Service over Ethernet (MEF 8)
* www.mef.net
*
* Copyright 2018, AimValley B.V.
* Jaap Keuter <jkeuter@aimvalley.nl>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <epan/etypes.h>
#include <epan/dissectors/packet-rtp.h>
void proto_register_cesoeth(void);
void proto_reg_handoff_cesoeth(void);
static int proto_cesoeth = -1;
static int hf_cesoeth_pw_ecid = -1;
static int hf_cesoeth_pw_res = -1;
static int hf_cesoeth_cw = -1;
static int hf_cesoeth_cw_reserved1 = -1;
static int hf_cesoeth_cw_l = -1;
static int hf_cesoeth_cw_r = -1;
static int hf_cesoeth_cw_l0_m = -1;
static int hf_cesoeth_cw_l1_m = -1;
static int hf_cesoeth_cw_frg = -1;
static int hf_cesoeth_cw_len = -1;
static int hf_cesoeth_cw_seq = -1;
static int hf_cesoeth_padding = -1;
static gint ett_cesoeth = -1;
static gint ett_cesoeth_cw = -1;
static expert_field ei_cesoeth_reserved = EI_INIT;
static expert_field ei_cesoeth_length = EI_INIT;
static int* const cesoeth_l0_cw[] =
{
&hf_cesoeth_cw_reserved1,
&hf_cesoeth_cw_l,
&hf_cesoeth_cw_r,
&hf_cesoeth_cw_l0_m,
&hf_cesoeth_cw_frg,
&hf_cesoeth_cw_len,
&hf_cesoeth_cw_seq,
NULL
};
static int* const cesoeth_l1_cw[] =
{
&hf_cesoeth_cw_reserved1,
&hf_cesoeth_cw_l,
&hf_cesoeth_cw_r,
&hf_cesoeth_cw_l1_m,
&hf_cesoeth_cw_frg,
&hf_cesoeth_cw_len,
&hf_cesoeth_cw_seq,
NULL
};
static const value_string frg_names[] =
{
{ 0, "No fragmentation" },
{ 1, "First fragment" },
{ 2, "Last fragment" },
{ 3, "Intermediate fragment" },
{ 0, NULL }
};
static const value_string l0_m_names[] =
{
{ 0, "No local TDM defect" },
{ 1, "Reserved" },
{ 2, "RDI on TDM input" },
{ 3, "Non-TDM data" },
{ 0, NULL }
};
static const value_string l1_m_names[] =
{
{ 0, "TDM defect" },
{ 1, "Reserved" },
{ 2, "Reserved" },
{ 3, "Reserved" },
{ 0, NULL }
};
/* Preferences */
static gboolean has_rtp_header = FALSE;
static gboolean heuristic_rtp_header = TRUE;
static int
dissect_cesoeth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
proto_tree *cesoeth_tree;
proto_item *cesoeth_ti;
proto_item *bitmask_ti;
int offset = 0;
guint32 ecid, reserved;
gboolean l_bit, r_bit;
guint8 m_bits, frg;
gint cw_len, padding_len, tail_len, payload_len;
guint16 sn;
tvbuff_t *next_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CESoETH");
col_clear(pinfo->cinfo, COL_INFO);
cesoeth_ti = proto_tree_add_item(tree, proto_cesoeth, tvb, 0, -1, ENC_NA);
cesoeth_tree = proto_item_add_subtree(cesoeth_ti, ett_cesoeth);
proto_tree_add_item_ret_uint(cesoeth_tree, hf_cesoeth_pw_ecid, tvb, offset, 4, ENC_BIG_ENDIAN, &ecid);
col_append_fstr(pinfo->cinfo, COL_INFO, "ECID: 0x%05x", ecid);
bitmask_ti = proto_tree_add_item_ret_uint(cesoeth_tree, hf_cesoeth_pw_res, tvb, offset, 4, ENC_BIG_ENDIAN, &reserved);
if (reserved != 0x102)
expert_add_info_format(pinfo, bitmask_ti, &ei_cesoeth_reserved, "Reserved field must be 0x102");
offset += 4;
/*
* CES header control word
*
* bits name description
* 31-28 reserved set to 0
* 27 L-bit set to 1 to indicate local TDM failure
* 26 R-bit set to 1 to indicate remote loss of frame
* 25-24 M-bits modifier bits
* 23-22 FRG bits fragmentation bits
* 21-16 length length (0 if no padding applied)
* 15-0 sequence sequence number
*/
l_bit = (tvb_get_guint8(tvb, offset) & 0x08) ? TRUE : FALSE;
r_bit = (tvb_get_guint8(tvb, offset) & 0x04) ? TRUE : FALSE;
m_bits = (tvb_get_guint8(tvb, offset) & 0x03);
frg = tvb_get_bits8(tvb, 40, 2);
cw_len = tvb_get_bits8(tvb, 42, 6);
sn = tvb_get_ntohs(tvb, offset + 2);
col_append_fstr(pinfo->cinfo, COL_INFO, ", SN: %u", sn);
if (l_bit)
{
bitmask_ti = proto_tree_add_bitmask(cesoeth_tree, tvb, offset, hf_cesoeth_cw, ett_cesoeth_cw, cesoeth_l1_cw, ENC_NA);
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "%s", val_to_str_const(m_bits, l1_m_names, "Unknown"));
} else {
bitmask_ti = proto_tree_add_bitmask(cesoeth_tree, tvb, offset, hf_cesoeth_cw, ett_cesoeth_cw, cesoeth_l0_cw, ENC_NA);
if (m_bits)
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "%s", val_to_str_const(m_bits, l0_m_names, "Unknown"));
}
if (cw_len >= 42)
{
/*
* Now we have to go spelunking in the bitmask tree for the length item
* in order to add an expert item to it.
*/
proto_tree *bm_tree = proto_item_get_subtree(bitmask_ti);
if (bm_tree) {
proto_item *pi;
for (pi = tree->first_child; pi; pi = pi->next)
{
field_info *fi;
fi = PITEM_FINFO(pi);
if (fi && (fi->hfinfo->id == hf_cesoeth_cw_len))
break;
}
expert_add_info_format(pinfo, pi, &ei_cesoeth_length, "Length can not be 42 or larger");
}
cw_len = 0; /* Put a stop to this madness */
}
if (r_bit)
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL, "Remote loss of frame");
if (frg)
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "%s", val_to_str_const(frg, frg_names, "Unknown"));
offset += 4;
/*
* When L is set the TDM payload MAY be missing.
* But also when snap value is used on capture.
* Will the optional RTP header be there when the TDM payload is missing? I guess so.
* Length includes the size of the CW (being 4), the optional RTP header (being 12) and
* the TDM payload, as long as it doesn't exceed 42 octets. Length > 0 indicates padding,
* which must NOT be passed to the RTP dissector, it's not RTP padding.
*/
padding_len = (cw_len > 0) ? (42 - cw_len) : 0;
tail_len = tvb_reported_length_remaining(tvb, offset);
payload_len = tail_len - padding_len;
if (payload_len > 0)
{
next_tvb = tvb_new_subset_length(tvb, offset, payload_len);
if ((has_rtp_header) ||
((heuristic_rtp_header) &&
/* Check for RTP version 2, the other fields must be zero */
(tvb_get_guint8(tvb, offset) == 0x80) &&
/* Check the marker is zero. Unfortnately PT is not always from the dynamic range */
((tvb_get_guint8(tvb, offset + 1) & 0x80) == 0) &&
/* The sequence numbers from cw and RTP header must match */
(tvb_get_ntohs(tvb, offset + 2) == sn)))
{
struct _rtp_info rtp_info;
gint rtp_header_len = dissect_rtp_shim_header(tvb, offset, pinfo, cesoeth_tree, &rtp_info);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CESoETH (w RTP)");
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "RTP PT: %u, SSRC: 0x%X, Seq: %u, Time=%u",
rtp_info.info_payload_type,
rtp_info.info_sync_src,
rtp_info.info_seq_num,
rtp_info.info_timestamp
);
next_tvb = tvb_new_subset_length(tvb, offset + rtp_header_len, payload_len - rtp_header_len);
}
call_data_dissector(next_tvb, pinfo, tree);
offset += payload_len;
}
if (padding_len > 0)
{
proto_tree_add_item(cesoeth_tree, hf_cesoeth_padding, tvb, offset, padding_len, ENC_NA);
offset += padding_len;
}
return offset;
}
void
proto_register_cesoeth(void)
{
static hf_register_info hf[] = {
{ &hf_cesoeth_pw_ecid,
{ "ECID", "cesoeth.ecid", FT_UINT32, BASE_HEX,
NULL, 0xFFFFF000, NULL, HFILL }},
{ &hf_cesoeth_pw_res,
{ "Reserved", "cesoeth.res", FT_UINT32, BASE_HEX,
NULL, 0x00000FFF, "Reserved (0x102)", HFILL }},
{ &hf_cesoeth_cw,
{ "Control word", "cesoeth.cw", FT_UINT32, BASE_HEX,
NULL, 0x0, NULL, HFILL }},
{ &hf_cesoeth_cw_reserved1,
{ "Reserved", "cesoeth.cw.reserved", FT_UINT32, BASE_HEX,
NULL, 0xF0000000, NULL, HFILL }},
{ &hf_cesoeth_cw_l,
{ "L-bit", "cesoeth.cw.l", FT_BOOLEAN, 32,
NULL, 0x08000000, "Local TDM failure", HFILL }},
{ &hf_cesoeth_cw_r,
{ "R-bit", "cesoeth.cw.r", FT_BOOLEAN, 32,
NULL, 0x04000000, "Remote Loss of Frames indication", HFILL }},
{ &hf_cesoeth_cw_l0_m,
{ "M-bits", "cesoeth.cw.m", FT_UINT32, BASE_HEX,
VALS(l0_m_names), 0x03000000, "Modifier bits", HFILL }},
{ &hf_cesoeth_cw_l1_m,
{ "M-bits", "cesoeth.cw.m", FT_UINT32, BASE_HEX,
VALS(l1_m_names), 0x03000000, "Modifier bits", HFILL }},
{ &hf_cesoeth_cw_frg,
{ "Frg", "cesoeth.cw.frg", FT_UINT32, BASE_HEX,
VALS(frg_names), 0x00C00000, "Fragmentation bits", HFILL }},
{ &hf_cesoeth_cw_len,
{ "Len", "cesoeth.cw.len", FT_UINT32, BASE_DEC,
NULL, 0x003F0000, "Length", HFILL }},
{ &hf_cesoeth_cw_seq,
{ "SN", "cesoeth.cw.sn", FT_UINT32, BASE_DEC,
NULL, 0x0000FFFF, "Sequence number", HFILL }},
{ &hf_cesoeth_padding,
{ "Padding", "cesoeth.padding", FT_BYTES, BASE_NONE,
NULL, 0x0, NULL, HFILL }}
};
static gint *ett[] = {
&ett_cesoeth,
&ett_cesoeth_cw
};
static ei_register_info ei[] = {
{ &ei_cesoeth_reserved,
{ "cesoeth.reserved", PI_PROTOCOL, PI_WARN,
"Reserved field", EXPFILL }},
{ &ei_cesoeth_length,
{ "cesoeth.length", PI_PROTOCOL, PI_WARN,
"Length field", EXPFILL }}
};
module_t *cesoeth_module;
expert_module_t* expert_cesoeth;
proto_cesoeth = proto_register_protocol("Circuit Emulation Service over Ethernet", "CESoETH", "cesoeth");
proto_register_field_array(proto_cesoeth, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_cesoeth = expert_register_protocol(proto_cesoeth);
expert_register_field_array(expert_cesoeth, ei, array_length(ei));
cesoeth_module = prefs_register_protocol(proto_cesoeth, NULL);
prefs_register_bool_preference(cesoeth_module, "rtp_header", "RTP header in CES payload",
"Whether or not the RTP header is present in the CES payload.", &has_rtp_header);
prefs_register_bool_preference(cesoeth_module, "rtp_header_heuristic", "Try to find RTP header in CES payload",
"Heuristically determine if an RTP header is present in the CES payload.", &heuristic_rtp_header);
}
void
proto_reg_handoff_cesoeth(void)
{
dissector_handle_t cesoeth_handle;
cesoeth_handle = create_dissector_handle(dissect_cesoeth, proto_cesoeth);
dissector_add_uint("ethertype", ETHERTYPE_CESOETH, cesoeth_handle);
}
/*
* 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:
*/
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