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wireshark/epan/dissectors/packet-opus.c

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/* packet-opus.c
* Routines for OPUS dissection
* Copyright 2014, Owen Williams williams.owen@gmail.com
*
* 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 "tvbuff.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <ftypes/ftypes.h>
#include <glibconfig.h>
#include <proto.h>
#include <stdint.h>
#define MAX_FRAMES_COUNT 48
void proto_reg_handoff_opus(void);
void proto_register_opus(void);
static range_t *g_dynamic_payload_type_range = NULL;
static dissector_handle_t opus_handle;
/* Initialize the protocol and registered fields */
static int proto_opus = -1;
static int hf_opus_toc_config = -1;
static int hf_opus_toc_s = -1;
static int hf_opus_toc_c = -1;
static int hf_opus_frame = -1;
static int hf_opus_frame_size = -1;
static int hf_opus_frame_count_v = -1;
static int hf_opus_frame_count_p = -1;
static int hf_opus_frame_count_m = -1;
static int hf_opus_padding = -1;
/* Initialize the subtree pointers */
static gint ett_opus = -1;
static expert_field ei_opus_err_r1 = EI_INIT;
static expert_field ei_opus_err_r2 = EI_INIT;
static expert_field ei_opus_err_r3 = EI_INIT;
static expert_field ei_opus_err_r4 = EI_INIT;
static expert_field ei_opus_err_r5 = EI_INIT;
static expert_field ei_opus_err_r6 = EI_INIT;
static expert_field ei_opus_err_r7 = EI_INIT;
/* From RFC6716 chapter 3.1
* The top five bits of the TOC byte, labeled "config", encode one of 32
* possible configurations of operating mode, audio bandwidth, and frame size.
*/
static const value_string opus_codec_toc_config_request_vals[] = {
{0, "NB, SILK-only ptime=10"},
{1, "NB, SILK-only ptime=20"},
{2, "NB, SILK-only ptime=30"},
{3, "NB, SILK-only ptime=40"},
{4, "MB, SILK-only ptime=10"},
{5, "MB, SILK-only ptime=20"},
{6, "MB, SILK-only ptime=30"},
{7, "MB, SILK-only ptime=40"},
{8, "WB, SILK-only ptime=10"},
{9, "WB, SILK-only ptime=20"},
{10, "WB, SILK-only ptime=30"},
{11, "WB, SILK-only ptime=40"},
{12, "SWB, Hybrid ptime=10"},
{13, "SWB, Hybrid ptime=20"},
{14, "FB, Hybrid ptime=10"},
{15, "FB, Hybrid ptime=20"},
{16, "NB, CELT-only ptime=2.5"},
{17, "NB, CELT-only ptime=5"},
{18, "NB, CELT-only ptime=10"},
{19, "NB, CELT-only ptime=20"},
{20, "WB, CELT-only ptime=2.5"},
{21, "WB, CELT-only ptime=5"},
{22, "WB, CELT-only ptime=10"},
{23, "WB, CELT-only ptime=20"},
{24, "SWB, CELT-only ptime=2.5"},
{25, "SWB, CELT-only ptime=5"},
{26, "SWB, CELT-only ptime=10"},
{27, "SWB, CELT-only ptime=20"},
{28, "FB, CELT-only ptime=2.5"},
{29, "FB, CELT-only ptime=5"},
{30, "FB, CELT-only ptime=10"},
{31, "FB, CELT-only ptime=20"},
{0, NULL}};
static value_string_ext opus_codec_toc_config_request_vals_ext
= VALUE_STRING_EXT_INIT(opus_codec_toc_config_request_vals);
static const true_false_string toc_s_bit_vals = {"stereo", "mono"};
static const true_false_string fc_v_bit_vals = {"VBR", "CBR"};
static const true_false_string fc_p_bit_vals = {"Padding", "No Padding"};
static const value_string opus_codec_toc_c_request_vals[]
= {{0, "1 frame in the packet"},
{1, "2 frames in the packet, each with equal compressed size"},
{2, "2 frames in the packet, with different compressed sizes"},
{3, "an arbitrary number of frames in the packet"},
{0, NULL}};
static value_string_ext opus_codec_toc_c_request_vals_ext
= VALUE_STRING_EXT_INIT(opus_codec_toc_c_request_vals);
static int
parse_size_field(const unsigned char *ch, int32_t cn, int16_t *size)
{
if (cn < 1) {
*size = -1;
return -1;
}
else if (ch[0] < 252) {
*size = ch[0];
return 1;
}
else if (cn < 2) {
*size = -1;
return -1;
}
else {
*size = 4 * ch[1] + ch[0];
return 2;
}
}
static int16_t
opus_packet_get_samples_per_frame(const unsigned char *data, int16_t Fs)
{
int audiosize;
if (data[0] & 0x80) {
audiosize = ((data[0] >> 3) & 0x3);
audiosize = (Fs << audiosize) / 400;
}
else if ((data[0] & 0x60) == 0x60) {
audiosize = (data[0] & 0x08) ? Fs / 50 : Fs / 100;
}
else {
audiosize = ((data[0] >> 3) & 0x3);
if (audiosize == 3)
audiosize = Fs * 60 / 1000;
else
audiosize = (Fs << audiosize) / 100;
}
return audiosize;
}
static int
dissect_opus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
int idx;
proto_item *item;
proto_tree *opus_tree;
gint pkt_total = 0, offset = 0;
guint cap_len = 0;
guint8 ch = 0, toc = 0, octet[2] = {0, 0};
int octet_cnt = 0;
int bytes = 0;
int16_t framesize = 0;
struct FRAME_T {
int16_t begin;
int16_t size;
} frames[MAX_FRAMES_COUNT] = {{0}};
int frame_count = 0;
static int *toc_fields[]
= {&hf_opus_toc_config, &hf_opus_toc_s, &hf_opus_toc_c, NULL};
static int *frame_count_fields[]
= {&hf_opus_frame_count_v, &hf_opus_frame_count_p,
&hf_opus_frame_count_m, NULL};
col_set_str(pinfo->cinfo, COL_PROTOCOL, "OPUS");
item = proto_tree_add_item(tree, proto_opus, tvb, 0, -1, ENC_NA);
opus_tree = proto_item_add_subtree(item, ett_opus);
/*
* A ToC entry takes the following format, details defined in section-3.1:
*
* 0 1 2 3 4 5 6 7
* +-+-+-+-+-+-+-+-+
* | config |s| c |
* +-+-+-+-+-+-+-+-+
*/
proto_tree_add_bitmask_list(opus_tree, tvb, offset, 1, toc_fields, ENC_NA);
cap_len = tvb_captured_length(tvb);
pkt_total = tvb_captured_length_remaining(tvb, offset);
if (pkt_total <= 0) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r1);
return cap_len;
}
toc = tvb_get_guint8(tvb, offset++);
switch (toc & 0x3) {
case 0: /* One frame */
frames[0].begin = offset;
frames[0].size = pkt_total - offset;
frame_count = 1;
break;
case 1: /* Two CBR frames */
if ((pkt_total - offset) & 0x1) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r3);
return cap_len;
}
frames[0].begin = offset;
frames[0].size = frames[1].size = (pkt_total - offset) / 2;
frames[1].begin = frames[0].begin + frames[0].size;
frame_count = 2;
break;
case 2: /* Two VBR frames */
if (offset >= pkt_total) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r4);
return cap_len;
}
/* offset < pkt_total */
octet[octet_cnt++] = tvb_get_guint8(tvb, offset);
if (offset + 1 < pkt_total) {
octet[octet_cnt++] = tvb_get_guint8(tvb, offset + 1);
}
bytes = parse_size_field(octet, octet_cnt, &framesize);
if (framesize < 0 || framesize > pkt_total) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r1);
return cap_len;
}
proto_tree_add_item(opus_tree, hf_opus_frame_size, tvb, offset, bytes,
ENC_NA);
offset += bytes;
/* frame[0] has size header, frame[1] is remaining */
frames[0].begin = offset;
frames[0].size = framesize;
frames[1].begin = frames[0].begin + framesize;
frames[1].size = -1;
frame_count = 2;
break;
/* Multiple CBR/VBR frames (from 0 to 120 ms) */
default: /* case 3:*/
if ((pkt_total - offset) < 2) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r6);
return cap_len;
}
proto_tree_add_bitmask_list(opus_tree, tvb, offset, 1,
frame_count_fields, ENC_NA);
/* Number of frames encoded in bits 0 to 5 */
ch = tvb_get_guint8(tvb, offset++);
frame_count = ch & 0x3F;
framesize = opus_packet_get_samples_per_frame(&toc, 48000U);
if (frame_count <= 0
|| framesize * frame_count > 120 * MAX_FRAMES_COUNT) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r5);
return cap_len;
}
/* Padding flag (bit 6) used */
if (ch & 0x40) {
int p;
gint padding_size = 0;
gint padding_begin = offset;
do {
int tmp;
if (offset >= pkt_total) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r7);
return cap_len;
}
p = tvb_get_guint8(tvb, offset++);
tmp = p == 255 ? 254 : p;
padding_size += tmp;
} while (p == 255);
proto_tree_add_item(opus_tree, hf_opus_padding, tvb, padding_begin,
padding_size, ENC_NA);
offset = padding_begin + padding_size;
}
if (offset >= pkt_total) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r7);
return cap_len;
}
/* VBR flag is bit 7 */
if (ch & 0x80) { /* VBR case */
for (idx = 0; idx < frame_count; idx++) {
octet_cnt = 0;
octet[octet_cnt++] = tvb_get_guint8(tvb, offset);
if (offset + 1 < pkt_total) {
octet[octet_cnt++] = tvb_get_guint8(tvb, offset);
}
bytes = parse_size_field(octet, octet_cnt, &frames[idx].size);
if (frames[idx].size < 0
|| frames[idx].size > (pkt_total - offset)) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r1);
return cap_len;
}
proto_tree_add_item(opus_tree, hf_opus_frame_size, tvb, offset,
bytes, ENC_NA);
offset += bytes;
}
for (idx = 0; idx < frame_count; idx++) {
frames[idx].begin = offset;
offset += frames[idx].size;
}
if (offset > pkt_total) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r7);
return cap_len;
}
}
else { /* CBR case */
guint frame_size = (pkt_total - offset) / frame_count;
if (frame_size * frame_count != (guint)(pkt_total - offset)) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r6);
return cap_len;
}
for (idx = 0; idx < frame_count; idx++) {
frames[idx].begin = offset + idx * frame_size;
frames[idx].size = frame_size;
}
}
break;
}
for (idx = 0; idx < frame_count; idx++) {
struct FRAME_T *f = &frames[idx];
/* reject the frame which is larger than 1275. */
if (f->size > 1275) {
expert_add_info(pinfo, opus_tree, &ei_opus_err_r2);
return cap_len;
}
proto_tree_add_item(opus_tree, hf_opus_frame, tvb, f->begin, f->size,
ENC_NA);
}
return cap_len;
}
void
proto_register_opus(void)
{
module_t *opus_module;
expert_module_t* expert_opus;
static hf_register_info hf[] = {
{&hf_opus_toc_config,
{"TOC.config", "opus.TOC.config", FT_UINT8, BASE_DEC | BASE_EXT_STRING,
&opus_codec_toc_config_request_vals_ext, 0xF8, "Opus TOC config",
HFILL}},
{&hf_opus_toc_s,
{"TOC.S bit", "opus.TOC.s", FT_BOOLEAN, SEP_DOT, TFS(&toc_s_bit_vals),
0x04, NULL, HFILL}},
{&hf_opus_toc_c,
{"TOC.C bits", "opus.TOC.c", FT_UINT8, BASE_DEC | BASE_EXT_STRING,
&opus_codec_toc_c_request_vals_ext, 0x03, "Opus TOC code", HFILL}},
{&hf_opus_frame_count_m,
{"Frame Count.m", "opus.FC.m", FT_UINT8, BASE_DEC, NULL, 0x3F,
"Frame Count", HFILL}},
{&hf_opus_frame_count_p,
{"Frame Count.p bit", "opus.FC.p", FT_BOOLEAN, SEP_DOT,
TFS(&fc_p_bit_vals), 0x40, NULL, HFILL}},
{&hf_opus_frame_count_v,
{"Frame Count.v bit", "opus.FC.v", FT_BOOLEAN, SEP_DOT,
TFS(&fc_v_bit_vals), 0x80, NULL, HFILL}},
{&hf_opus_frame_size,
{"Frame Size", "opus.frame_size", FT_BYTES, BASE_NONE, NULL, 0x0, NULL,
HFILL}},
{&hf_opus_frame,
{"Frame Data", "opus.frame_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL,
HFILL}},
{&hf_opus_padding,
{"Padding", "opus.padding", FT_BYTES, BASE_NONE, NULL, 0x0, NULL,
HFILL}},
};
static gint *ett[] = { &ett_opus, };
static ei_register_info ei[] = {
{&ei_opus_err_r1,
{"opus.violate_r1", PI_PROTOCOL, PI_ERROR,
"Error:[R1] Packets are at least one byte.", EXPFILL}},
{&ei_opus_err_r2,
{"opus.violate_r2", PI_MALFORMED, PI_ERROR,
"Error:[R2] No implicit frame length is larger than 1275 bytes.",
EXPFILL}},
{&ei_opus_err_r3,
{"opus.violate_r3", PI_MALFORMED, PI_ERROR,
"Error:[R3] Code 1 packets have an odd total length, N, so that "
"(N-1)/2 is an integer.",
EXPFILL}},
{&ei_opus_err_r4,
{"opus.violate_r4", PI_MALFORMED, PI_ERROR,
"Error:[R4] Code 2 packets have enough bytes after the TOC for a "
"valid frame length, and that length is no larger than the number of"
"bytes remaining in the packet.",
EXPFILL}},
{&ei_opus_err_r5,
{"opus.violate_r5", PI_PROTOCOL, PI_ERROR,
"Error:[R5] Code 3 packets contain at least one frame, but no more "
"than 120 ms of audio total.",
EXPFILL}},
{&ei_opus_err_r6,
{"opus.violate_r6", PI_PROTOCOL, PI_ERROR,
"Error:[R6] The length of a CBR code 3 packet, N, is at least two "
"bytes, the number of bytes added to indicate the padding size plus "
"the trailing padding bytes themselves, P, is no more than N-2, and "
"the frame count, M, satisfies the constraint that (N-2-P) is a "
"non-negative integer multiple of M.",
EXPFILL}},
{&ei_opus_err_r7,
{"opus.violate_r7", PI_PROTOCOL, PI_ERROR,
"Error:[R7] VBR code 3 packets are large enough to contain all the "
"header bytes (TOC byte, frame count byte, any padding length bytes, "
"and any frame length bytes), plus the length of the first M-1 "
"frames, plus any trailing padding bytes.",
EXPFILL}},
};
proto_opus
= proto_register_protocol("Opus Interactive Audio Codec", /* name */
"OPUS", /* short name */
"opus" /* abbrev */
);
proto_register_field_array(proto_opus, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
opus_module = prefs_register_protocol(proto_opus, proto_reg_handoff_opus);
expert_opus = expert_register_protocol(proto_opus);
expert_register_field_array(expert_opus, ei, array_length(ei));
prefs_register_range_preference(opus_module, "dynamic.payload.type",
"OPUS dynamic payload types",
"Dynamic payload types which will be "
"interpreted as OPUS; Values must be in "
"the range 1 - 127",
&g_dynamic_payload_type_range, 127);
opus_handle = register_dissector("opus", dissect_opus, proto_opus);
}
void
proto_reg_handoff_opus(void)
{
static range_t *dynamic_payload_type_range = NULL;
static gboolean opus_prefs_initialized = FALSE;
if (!opus_prefs_initialized) {
dissector_add_string("rtp_dyn_payload_type" , "OPUS", opus_handle);
opus_prefs_initialized = TRUE;
} else {
dissector_delete_uint_range("rtp.pt", dynamic_payload_type_range, opus_handle);
wmem_free(wmem_epan_scope(), dynamic_payload_type_range);
}
dynamic_payload_type_range = range_copy(wmem_epan_scope(), g_dynamic_payload_type_range);
range_remove_value(wmem_epan_scope(), &dynamic_payload_type_range, 0);
dissector_add_uint_range("rtp.pt", dynamic_payload_type_range, opus_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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