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wireshark/epan/dissectors/packet-mp2t.c
John Thacker 636c797627 MP2T: Only call subdissectors on the last fragment 
When there is more than one TSP in a frame, the fragment at the
end of one TSP and the first fragment in the next have the same
layer number as well as frame number. So use other information
about whether we have the last fragment to avoid calling subdissectors
extra times (which can interfere with retrieving the packet analysis
proto data on the subsequent passes.)
2022-03-01 00:59:21 +00:00

1870 lines
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/* packet-mp2t.c
*
* Routines for RFC 2250 MPEG2 (ISO/IEC 13818-1) Transport Stream dissection
*
* Copyright 2006, Erwin Rol <erwin@erwinrol.com>
* Copyright 2012-2014, Guy Martin <gmsoft@tuxicoman.be>
*
* 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 <wiretap/wtap.h>
#include <epan/rtp_pt.h>
#include <epan/conversation.h>
#include <epan/expert.h>
#include <epan/reassemble.h>
#include <epan/proto_data.h>
#include <epan/exceptions.h>
#include <epan/show_exception.h>
#include "packet-l2tp.h"
#include "packet-mp2t.h"
void proto_register_mp2t(void);
void proto_reg_handoff_mp2t(void);
#define MP2T_PID_DOCSIS 0x1FFE
#define MP2T_PID_NULL 0x1FFF
static dissector_handle_t mp2t_handle;
static dissector_handle_t docsis_handle;
static dissector_handle_t mpeg_pes_handle;
static dissector_handle_t mpeg_sect_handle;
static heur_dissector_list_t heur_subdissector_list;
static int proto_mp2t = -1;
static gint ett_mp2t = -1;
static gint ett_mp2t_header = -1;
static gint ett_mp2t_af = -1;
static gint ett_mp2t_analysis = -1;
static gint ett_stuff = -1;
static int hf_mp2t_header = -1;
static int hf_mp2t_sync_byte = -1;
static int hf_mp2t_tei = -1;
static int hf_mp2t_pusi = -1;
static int hf_mp2t_tp = -1;
static int hf_mp2t_pid = -1;
static int hf_mp2t_tsc = -1;
static int hf_mp2t_afc = -1;
static int hf_mp2t_cc = -1;
/* static int hf_mp2t_analysis_flags = -1; */
static int hf_mp2t_analysis_skips = -1;
static int hf_mp2t_analysis_drops = -1;
#define MP2T_SYNC_BYTE_MASK 0xFF000000
#define MP2T_TEI_MASK 0x00800000
#define MP2T_PUSI_MASK 0x00400000
#define MP2T_TP_MASK 0x00200000
#define MP2T_PID_MASK 0x001FFF00
#define MP2T_TSC_MASK 0x000000C0
#define MP2T_AFC_MASK 0x00000030
#define MP2T_CC_MASK 0x0000000F
#define MP2T_SYNC_BYTE_SHIFT 24
#define MP2T_TEI_SHIFT 23
#define MP2T_PUSI_SHIFT 22
#define MP2T_TP_SHIFT 21
#define MP2T_PID_SHIFT 8
#define MP2T_TSC_SHIFT 6
#define MP2T_AFC_SHIFT 4
#define MP2T_CC_SHIFT 0
static int hf_mp2t_af = -1;
static int hf_mp2t_af_length = -1;
static int hf_mp2t_af_di = -1;
static int hf_mp2t_af_rai = -1;
static int hf_mp2t_af_espi = -1;
static int hf_mp2t_af_pcr_flag = -1;
static int hf_mp2t_af_opcr_flag = -1;
static int hf_mp2t_af_sp_flag = -1;
static int hf_mp2t_af_tpd_flag = -1;
static int hf_mp2t_af_afe_flag = -1;
#define MP2T_AF_DI_MASK 0x80
#define MP2T_AF_RAI_MASK 0x40
#define MP2T_AF_ESPI_MASK 0x20
#define MP2T_AF_PCR_MASK 0x10
#define MP2T_AF_OPCR_MASK 0x08
#define MP2T_AF_SP_MASK 0x04
#define MP2T_AF_TPD_MASK 0x02
#define MP2T_AF_AFE_MASK 0x01
#define MP2T_AF_DI_SHIFT 7
#define MP2T_AF_RAI_SHIFT 6
#define MP2T_AF_ESPI_SHIFT 5
#define MP2T_AF_PCR_SHIFT 4
#define MP2T_AF_OPCR_SHIFT 3
#define MP2T_AF_SP_SHIFT 2
#define MP2T_AF_TPD_SHIFT 1
#define MP2T_AF_AFE_SHIFT 0
static int hf_mp2t_af_pcr = -1;
static int hf_mp2t_af_opcr = -1;
static int hf_mp2t_af_sc = -1;
static int hf_mp2t_af_tpd_length = -1;
static int hf_mp2t_af_tpd = -1;
static int hf_mp2t_af_e_length = -1;
static int hf_mp2t_af_e_ltw_flag = -1;
static int hf_mp2t_af_e_pr_flag = -1;
static int hf_mp2t_af_e_ss_flag = -1;
static int hf_mp2t_af_e_reserved = -1;
#define MP2T_AF_E_LTW_FLAG_MASK 0x80
#define MP2T_AF_E_PR_FLAG_MASK 0x40
#define MP2T_AF_E_SS_FLAG_MASK 0x20
static int hf_mp2t_af_e_reserved_bytes = -1;
static int hf_mp2t_af_stuffing_bytes = -1;
static int hf_mp2t_af_e_ltwv_flag = -1;
static int hf_mp2t_af_e_ltwo = -1;
static int hf_mp2t_af_e_pr_reserved = -1;
static int hf_mp2t_af_e_pr = -1;
static int hf_mp2t_af_e_st = -1;
static int hf_mp2t_af_e_dnau_32_30 = -1;
static int hf_mp2t_af_e_m_1 = -1;
static int hf_mp2t_af_e_dnau_29_15 = -1;
static int hf_mp2t_af_e_m_2 = -1;
static int hf_mp2t_af_e_dnau_14_0 = -1;
static int hf_mp2t_af_e_m_3 = -1;
/* static int hf_mp2t_payload = -1; */
static int hf_mp2t_stuff_bytes = -1;
static int hf_mp2t_pointer = -1;
/* proto data keys. Note that the packet_analysis_data structure is stored
* using the layer number, but since that is at wmem_file_scope() while
* the stream information is at pinfo->pool, they don't actually clash.
*/
#define MP2T_PROTO_DATA_STREAM 1
static const value_string mp2t_sync_byte_vals[] = {
{ MP2T_SYNC_BYTE, "Correct" },
{ 0, NULL }
};
static const value_string mp2t_pid_vals[] = {
{ 0x0000, "Program Association Table" },
{ 0x0001, "Conditional Access Table" },
{ 0x0002, "Transport Stream Description Table" },
{ 0x0003, "Reserved" },
{ 0x0004, "Reserved" },
{ 0x0005, "Reserved" },
{ 0x0006, "Reserved" },
{ 0x0007, "Reserved" },
{ 0x0008, "Reserved" },
{ 0x0009, "Reserved" },
{ 0x000A, "Reserved" },
{ 0x000B, "Reserved" },
{ 0x000C, "Reserved" },
{ 0x000D, "Reserved" },
{ 0x000E, "Reserved" },
{ 0x000F, "Reserved" },
{ 0x0010, "Network Information or Stuffing Table" },
{ 0x0011, "Service Description or Bouquet Association or Stuffing Table" },
{ 0x0012, "Event Information or Stuffing or Content Identifier Table" },
{ 0x0013, "Running Status or Stuffing Table" },
{ 0x0014, "Time and Date or Time Offset or Stuffing Table" },
{ 0x0015, "Network Synchronization" },
{ 0x0016, "Resolution Authority Record Notification Table" },
{ 0x0017, "Reserved For Future Use" },
{ 0x0018, "Reserved For Future Use" },
{ 0x0019, "Reserved For Future Use" },
{ 0x001A, "Reserved For Future Use" },
{ 0x001B, "Reserved For Future Use" },
{ 0x001C, "Inband Signaling" },
{ 0x001D, "Measurement" },
{ 0x001E, "Discontinuity Information Table" },
{ 0x001F, "Selection Information Table" },
{ 0x1FFE, "DOCSIS Data-over-cable well-known PID" },
{ 0x1FFF, "Null packet" },
{ 0, NULL }
};
/* Values below according ETSI ETR 289 */
static const value_string mp2t_tsc_vals[] = {
{ 0, "Not scrambled" },
{ 1, "Reserved" },
{ 2, "Packet scrambled with Even Key" },
{ 3, "Packet scrambled with Odd Key" },
{ 0, NULL }
};
static const value_string mp2t_afc_vals[] = {
{ 0, "Reserved" },
{ 1, "Payload only" },
{ 2, "Adaptation Field only" },
{ 3, "Adaptation Field and Payload" },
{ 0, NULL }
};
static gint ett_msg_fragment = -1;
static gint ett_msg_fragments = -1;
static int hf_msg_fragments = -1;
static int hf_msg_fragment = -1;
static int hf_msg_fragment_overlap = -1;
static int hf_msg_fragment_overlap_conflicts = -1;
static int hf_msg_fragment_multiple_tails = -1;
static int hf_msg_fragment_too_long_fragment = -1;
static int hf_msg_fragment_error = -1;
static int hf_msg_fragment_count = -1;
static int hf_msg_reassembled_in = -1;
static int hf_msg_reassembled_length = -1;
static int hf_msg_ts_packet_reassembled = -1;
static expert_field ei_mp2t_pointer = EI_INIT;
static expert_field ei_mp2t_cc_drop = EI_INIT;
static expert_field ei_mp2t_invalid_afc = EI_INIT;
static const fragment_items mp2t_msg_frag_items = {
/* Fragment subtrees */
&ett_msg_fragment,
&ett_msg_fragments,
/* Fragment fields */
&hf_msg_fragments,
&hf_msg_fragment,
&hf_msg_fragment_overlap,
&hf_msg_fragment_overlap_conflicts,
&hf_msg_fragment_multiple_tails,
&hf_msg_fragment_too_long_fragment,
&hf_msg_fragment_error,
&hf_msg_fragment_count,
/* Reassembled in field */
&hf_msg_reassembled_in,
/* Reassembled length field */
&hf_msg_reassembled_length,
/* Reassembled data field */
NULL,
/* Tag */
"Message fragments"
};
/* Data structure used for detecting CC drops
*
* conversation + direction
* |
* +-> mp2t_analysis_data
* |
* +-> pid_table (RB tree) (key: pid)
* | |
* | +-> pid_analysis_data (per pid)
* | +-> pid_analysis_data
* | +-> pid_analysis_data
* |
* +-> frame_table (RB tree) (key: pinfo->num)
* |
* +-> frame_analysis_data (only created if drop detected)
* |
* +-> ts_table (RB tree)
* |
* +-> ts_analysis_data (per TS subframe)
* +-> ts_analysis_data
* +-> ts_analysis_data
*/
static wmem_map_t *mp2t_stream_hashtable = NULL;
typedef struct {
const conversation_t* conv;
gint dir;
} mp2t_stream_key;
/* Hash functions */
static gint
mp2t_stream_equal(gconstpointer v, gconstpointer w)
{
const mp2t_stream_key *v1 = (const mp2t_stream_key *)v;
const mp2t_stream_key *v2 = (const mp2t_stream_key *)w;
gint result;
result = (v1->conv == v2->conv && v1->dir == v2->dir);
return result;
}
static guint
mp2t_stream_hash(gconstpointer v)
{
const mp2t_stream_key *key = (const mp2t_stream_key *)v;
/* Actually getting multiple streams in opposite directions is
* quite unlikely, so to optimize don't include it in the hash */
guint hash_val = GPOINTER_TO_UINT(key->conv);
return hash_val;
}
typedef struct mp2t_analysis_data {
/* This structure contains a tree containing data for the
* individual pid's, this is only used when packets are
* processed sequentially.
*/
wmem_tree_t *pid_table;
/* When detecting a CC drop, store that information for the
* given frame. This info is needed, when clicking around in
* wireshark, as the pid table data only makes sense during
* sequential processing. The flag pinfo->fd->visited is
* used to tell the difference.
*
*/
wmem_tree_t *frame_table;
/* Total counters per conversation / multicast stream */
guint32 total_skips;
guint32 total_discontinuity;
} mp2t_analysis_data_t;
enum pid_payload_type {
pid_pload_unknown,
pid_pload_docsis,
pid_pload_pes,
pid_pload_sect,
pid_pload_null
};
typedef struct subpacket_analysis_data {
guint32 frag_cur_pos;
guint32 frag_tot_len;
gboolean fragmentation;
guint32 frag_id;
} subpacket_analysis_data_t;
typedef struct packet_analysis_data {
/* Contain information for each MPEG2-TS packet in the current big packet */
wmem_tree_t *subpacket_table;
} packet_analysis_data_t;
/* Analysis TS frame info needed during sequential processing */
typedef struct pid_analysis_data {
guint16 pid;
gint8 cc_prev; /* Previous CC number */
enum pid_payload_type pload_type;
/* Fragments information used for first pass */
gboolean fragmentation;
guint32 frag_cur_pos;
guint32 frag_tot_len;
guint32 frag_id;
} pid_analysis_data_t;
/* Analysis info stored for a TS frame */
typedef struct ts_analysis_data {
guint16 pid;
gint8 cc_prev; /* Previous CC number */
guint8 skips; /* Skips between Ccs max 14 */
} ts_analysis_data_t;
typedef struct frame_analysis_data {
/* As each frame has several pid's, thus need a pid data
* structure per TS frame.
*/
wmem_tree_t *ts_table;
} frame_analysis_data_t;
static mp2t_analysis_data_t *
init_mp2t_conversation_data(void)
{
mp2t_analysis_data_t *mp2t_data;
mp2t_data = wmem_new0(wmem_file_scope(), struct mp2t_analysis_data);
mp2t_data->pid_table = wmem_tree_new(wmem_file_scope());
mp2t_data->frame_table = wmem_tree_new(wmem_file_scope());
mp2t_data->total_skips = 0;
mp2t_data->total_discontinuity = 0;
return mp2t_data;
}
static mp2t_analysis_data_t *
get_mp2t_conversation_data(mp2t_stream_key *key)
{
mp2t_stream_key *new_key;
mp2t_analysis_data_t *mp2t_data;
mp2t_data = (mp2t_analysis_data_t *)wmem_map_lookup(mp2t_stream_hashtable, key);
if (!mp2t_data) {
new_key = wmem_new(wmem_file_scope(), mp2t_stream_key);
*new_key = *key;
mp2t_data = init_mp2t_conversation_data();
wmem_map_insert(mp2t_stream_hashtable, new_key, mp2t_data);
}
return mp2t_data;
}
static frame_analysis_data_t *
init_frame_analysis_data(mp2t_analysis_data_t *mp2t_data, packet_info *pinfo)
{
frame_analysis_data_t *frame_analysis_data_p;
frame_analysis_data_p = wmem_new0(wmem_file_scope(), struct frame_analysis_data);
frame_analysis_data_p->ts_table = wmem_tree_new(wmem_file_scope());
/* Insert into mp2t tree */
wmem_tree_insert32(mp2t_data->frame_table, pinfo->num,
(void *)frame_analysis_data_p);
return frame_analysis_data_p;
}
static frame_analysis_data_t *
get_frame_analysis_data(mp2t_analysis_data_t *mp2t_data, packet_info *pinfo)
{
frame_analysis_data_t *frame_analysis_data_p;
frame_analysis_data_p = (frame_analysis_data_t *)wmem_tree_lookup32(mp2t_data->frame_table, pinfo->num);
return frame_analysis_data_p;
}
static pid_analysis_data_t *
get_pid_analysis(mp2t_analysis_data_t *mp2t_data, guint32 pid)
{
pid_analysis_data_t *pid_data;
pid_data = (pid_analysis_data_t *)wmem_tree_lookup32(mp2t_data->pid_table, pid);
if (!pid_data) {
pid_data = wmem_new0(wmem_file_scope(), struct pid_analysis_data);
pid_data->cc_prev = -1;
pid_data->pid = pid;
pid_data->frag_id = (pid << (32 - 13)) | 0x1;
wmem_tree_insert32(mp2t_data->pid_table, pid, (void *)pid_data);
}
return pid_data;
}
/* Structure to handle packets, spanned across
* multiple MPEG packets
*/
/* Reassembly functions */
typedef struct _mp2t_fragment_key {
guint32 conv_index; /* Just use the unique index */
int dir;
guint32 id;
} mp2t_fragment_key;
static guint
mp2t_fragment_hash(gconstpointer k)
{
const mp2t_fragment_key* key = (const mp2t_fragment_key*) k;
guint hash_val;
hash_val = 0;
/* In most captures there is only one conversation so optimize on
* only using the id for the hash. */
// hash_val += (key->conv_index << 2) + key->dir;
hash_val ^= key->id;
return hash_val;
}
static gint
mp2t_fragment_equal(gconstpointer k1, gconstpointer k2)
{
const mp2t_fragment_key* key1 = (const mp2t_fragment_key*) k1;
const mp2t_fragment_key* key2 = (const mp2t_fragment_key*) k2;
/* Compare the id first since it's the most likely to differ */
return (key1->id == key2->id) &&
(key1->conv_index == key2->conv_index) &&
(key1->dir == key2->dir);
}
/*
* Create a fragment key for permanent use; we are only copying ints,
* so our temporary keys are the same as permanent ones.
*/
static gpointer
mp2t_fragment_persistent_key(const packet_info *pinfo _U_, const guint32 id, const void *data)
{
mp2t_fragment_key *key = g_slice_new(mp2t_fragment_key);
DISSECTOR_ASSERT(data);
mp2t_stream_key *stream = (mp2t_stream_key *)data;
key->conv_index = stream->conv->conv_index;
key->dir = stream->dir;
key->id = id;
return (gpointer)key;
}
static void
mp2t_fragment_free_persistent_key(gpointer ptr)
{
mp2t_fragment_key *key = (mp2t_fragment_key *)ptr;
g_slice_free(mp2t_fragment_key, key);
}
static const reassembly_table_functions
mp2t_reassembly_table_functions = {
mp2t_fragment_hash,
mp2t_fragment_equal,
mp2t_fragment_persistent_key,
mp2t_fragment_persistent_key,
mp2t_fragment_free_persistent_key,
mp2t_fragment_free_persistent_key
};
static reassembly_table mp2t_reassembly_table;
static void
mp2t_dissect_packet(tvbuff_t *tvb, enum pid_payload_type pload_type,
packet_info *pinfo, proto_tree *tree)
{
dissector_handle_t handle = NULL;
switch (pload_type) {
case pid_pload_docsis:
handle = docsis_handle;
break;
case pid_pload_pes:
handle = mpeg_pes_handle;
break;
case pid_pload_sect:
handle = mpeg_sect_handle;
break;
default:
/* Should not happen */
break;
}
if (handle)
call_dissector(handle, tvb, pinfo, tree);
else
call_data_dissector(tvb, pinfo, tree);
}
/* Determine the length of a payload packet. If there aren't enough
* bytes to determine the length, returns -1. This will usually be
* called on the first fragment of a packet, but will be called
* on the second fragment if it returned -1 previously. (Returning
* -1 a second time indicates issues with dropped packets, etc.)
*/
static guint
mp2t_get_packet_length(tvbuff_t *tvb, guint offset, packet_info *pinfo,
guint32 frag_id, enum pid_payload_type pload_type)
{
mp2t_stream_key *stream;
fragment_head *frag;
tvbuff_t *len_tvb = NULL, *frag_tvb = NULL, *data_tvb = NULL;
gint pkt_len = 0;
guint remaining_len;
stream = (mp2t_stream_key *)p_get_proto_data(pinfo->pool, pinfo, proto_mp2t, MP2T_PROTO_DATA_STREAM);
if (pinfo->fd->visited) {
frag = fragment_get_reassembled_id(&mp2t_reassembly_table, pinfo, frag_id);
if (frag) {
len_tvb = frag->tvb_data;
offset = 0;
} else {
/* Not reassembled on the first pass. There are two possibilities:
* 1) An entire packet contained within a TSP, so it never was
* put in the table.
* 2) Dangling fragments at the end of the capture.
*/
frag = fragment_get(&mp2t_reassembly_table, pinfo, frag_id, stream);
if (!frag) {
/* This is the entire packet */
len_tvb = tvb;
} else {
/* Dangling packets at the end that failed to reassemble the
* first time around, so don't bother this time
*/
return -1;
}
}
} else {
frag = fragment_get(&mp2t_reassembly_table, pinfo, frag_id, stream);
if (frag)
frag = frag->next;
if (!frag) { /* First frame */
len_tvb = tvb;
} else {
/* Create a composite tvb out of the two */
frag_tvb = tvb_new_subset_remaining(frag->tvb_data, 0);
len_tvb = tvb_new_composite();
tvb_composite_append(len_tvb, frag_tvb);
data_tvb = tvb_new_subset_remaining(tvb, offset);
tvb_composite_append(len_tvb, data_tvb);
tvb_composite_finalize(len_tvb);
offset = frag->offset;
}
}
/* Get the next packet's size if possible; if not, return -1 */
remaining_len = tvb_reported_length_remaining(len_tvb, offset);
/* Normally the only time we would not enough info to determine the size
* of the encapsulated packet is when the first fragment is at the very end
* of a TSP, but prevent exceptions in the case of dropped and OOO frames.
*/
switch (pload_type) {
case pid_pload_docsis:
if (remaining_len < 4)
return -1;
pkt_len = tvb_get_ntohs(len_tvb, offset + 2) + 6;
break;
case pid_pload_pes:
if (remaining_len < 6)
return -1;
pkt_len = tvb_get_ntohs(len_tvb, offset + 4);
if (pkt_len) /* A size of 0 means size not bounded */
pkt_len += 6;
break;
case pid_pload_sect:
if (remaining_len < 3)
return -1;
pkt_len = (tvb_get_ntohs(len_tvb, offset + 1) & 0xFFF) + 3;
break;
default:
/* Should not happen */
break;
}
return pkt_len;
}
static void
mp2t_fragment_handle(tvbuff_t *tvb, guint offset, packet_info *pinfo,
proto_tree *tree, guint32 frag_id,
guint frag_offset, guint frag_len,
gboolean fragment_last, enum pid_payload_type pload_type)
{
fragment_head *frag_msg;
proto_item *ti;
tvbuff_t *new_tvb;
const char *save_proto;
mp2t_stream_key *stream;
gboolean save_fragmented;
save_fragmented = pinfo->fragmented;
pinfo->fragmented = TRUE;
/* It's possible that a fragment in the same packet set an address already
* (e.g., with MPE), which is why we use the conversation and direction not
* the addresses in the packet_info to reassemble.
*/
stream = (mp2t_stream_key *)p_get_proto_data(pinfo->pool, pinfo, proto_mp2t, MP2T_PROTO_DATA_STREAM);
/* check length; send frame for reassembly */
frag_msg = fragment_add_check(&mp2t_reassembly_table,
tvb, offset, pinfo, frag_id, stream,
frag_offset,
frag_len,
!fragment_last);
/* We only want to call subdissectors on the last fragment.
* processed_reassembled_data checks the frame number and layer number,
* but when there is more than one TSP in a frame, the fragment at the
* end of one TSP and the first fragment of the next have the same layer
* number. So use our own information about whether this is the last
* fragment to avoid calling subdissectors early and often.
*/
if (fragment_last) {
new_tvb = process_reassembled_data(tvb, offset, pinfo,
"Reassembled MP2T",
frag_msg, &mp2t_msg_frag_items,
NULL, tree);
} else {
new_tvb = NULL;
if (frag_msg != NULL) {
ti = proto_tree_add_uint(tree, hf_msg_reassembled_in, tvb, 0, 0, frag_msg->reassembled_in);
proto_item_set_generated(ti);
}
}
if (new_tvb) {
proto_tree_add_item(tree, hf_msg_ts_packet_reassembled, tvb, 0, 0, ENC_NA);
save_proto = pinfo->current_proto;
/*
* Dissect the reassembled packet.
*
* Because there isn't an explicit fragment ID (other than one
* we've made ourselves) if frames were dropped or out of order
* it's quite likely that a subdissector throws an exception.
* However, that doesn't mean we must stop dissecting, since we have
* the pointer to where the next upper level packet begins in the
* TSP begins. (Also, we want to make sure we increment our fragment
* ID and store the packet analysis data, which happens after this
* back in the calling function.)
*/
TRY {
mp2t_dissect_packet(new_tvb, pload_type, pinfo, tree);
}
CATCH_NONFATAL_ERRORS {
show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
pinfo->current_proto = save_proto;
}
ENDTRY;
} else {
col_set_str(pinfo->cinfo, COL_INFO, "[MP2T fragment of a reassembled packet]");
}
pinfo->fragmented = save_fragmented;
}
/*
* Reassembly of various payload types.
*
* DOCSIS MAC frames, PES packets, etc. may begin anywhere within an MPEG-TS
* packet or span multiple MPEG packets.
*
* The payload_unit_start_indicator bit in the MPEG-TS header, and the pointer
* field, are used to reassemble fragmented frames from MPEG-TS packets.
*
* If that bit is set, a higher-level packet begins in this MPEG-TS
* packet, and the MPEG-TS header is followed by a 1-octet pointer field.
* The value of the pointer field indicates at which byte the higher-
* level packet begins. If that bit is not set, the packet begun in
* an earlier MPEG-TS packet continues in this packet, with the data
* in the payload going after the data in the previous MPEG-TS packet
* (there can be more than one continuing packet).
*
* If the pointer field is non-zero, this MPEG-TS packet contains
* the conclusion of one higher-level packet and the beginning of
* the next packet.
*
* As the MPEG-TS packets are of a fixed size, stuff bytes are used
* as padding before the first byte of a higher-level packet as
* necessary.
*
* This diagram is from Data-Over-Cable Service Interface Specifications,
* Downstream RF Interface Specification, CM-SP-DRFI-I16-170111, section 7
* "DOWNSTREAM TRANSMISSION CONVERGENCE SUBLAYER", and shows how the
* higher-level packets are transported over the MPEG Transport Stream:
*
*+--------------------------------------------------------------------------------+
*|MPEG Header | pointer_field | stuff_bytes | Start of Packet #1 |
*|(PUSI = 1) | (= 0) | (0 or more) | (up to 183 bytes) |
*+--------------------------------------------------------------------------------+
*+--------------------------------------------------------------------------------+
*|MPEG Header | Continuation of Packet #1 |
*|(PUSI = 0) | (up to 183 bytes) |
*+--------------------------------------------------------------------------------+
*+---------------------------------------------------------------------------------+
*|MPEG Header | pointer_field |Tail of Packet #1 | stuff_bytes |Start of Packet #2 |
*|(PUSI = 1) | (= M) |(M bytes) | (0 or more) |(N bytes) |
*+---------------------------------------------------------------------------------+
*
* For PES and PSI, see ISO/IEC 13818-1 / ITU-T Rec. H.222.0 (05/2006),
* section 2.4.3.3 "Semantic definition of fields in Transport Stream packet
* layer", which says much the same thing.
*
* When the payload is PES packet data, note that there is no pointer_field;
* if the PUSI is 1 then the TS payload "will commence with the first byte
* of a PES packet" and "one and only one PES packet starts in this Transport
* Stream packet". Furthermore, section 2.4.3.5 "Semantic definition of
* fields in adaptation field" mentions that stuffing in an adaptation field
* is "the only method of stuffing allowed for Transport Stream packets
* carrying PES packets." Thus stuff_bytes is not relevant for MPEG-TS payloads
* carrying PES. (It is possible to have stuffing *inside* the PES packet,
* as seen in section 2.4.3.6 "PES packet" and 2.4.3.7 "Semantic definition
* of fields in PES packet", which is handled in the MPEG PES dissector.)
*
* For MPEG-TS packets carrying PSI (which includes private data sections), an
* alternative stuffing method is allowed. This method involves stuff bytes
* at the end of a MPEG-TS packet after the last section contained within
* (similar to the stuff_bytes that may appear after a continued section
* before the byte referenced by pointer_field). According to Section 2.4.4
* "Program specific information", once a packet stuffing byte 0xFF appears,
* "all bytes until the end of the Transport Stream packet shall also be
* stuffing bytes of value 0xFF." In other words, as section C.3 "The Mapping
* of Sections into Transport Stream Packets" elaborates, while multiple
* entire sections are allowed within a TS packet, "no gaps between sections
* within a Transport Stream packet are allowed by the syntax".
*
* However, this function is permissive in what it accepts to the extent
* possible; it will allow multiple PES packets in the same TS packet and
* stuffing bytes to follow PES packets (at least those that indicate their
* length) and will allow stuffing bytes between complete PSI sections.
*/
static void
mp2t_process_fragmented_payload(tvbuff_t *tvb, gint offset, guint remaining_len, packet_info *pinfo,
proto_tree *tree, proto_tree *header_tree, guint32 pusi_flag,
pid_analysis_data_t *pid_analysis)
{
tvbuff_t *next_tvb;
guint8 pointer = 0;
proto_item *pi;
guint stuff_len = 0;
proto_tree *stuff_tree;
packet_analysis_data_t *pdata = NULL;
subpacket_analysis_data_t *spdata = NULL;
guint32 frag_cur_pos = 0, frag_tot_len = 0;
gboolean fragmentation = FALSE;
guint32 frag_id = 0;
if (pusi_flag && pid_analysis->pload_type == pid_pload_unknown
&& remaining_len > 3) {
/* We should already have identified if it was a DOCSIS packet
* Remaining possibility is PES or SECT */
if (tvb_get_ntoh24(tvb, offset) == 0x000001) {
/* Looks like a PES packet to me ... */
pid_analysis->pload_type = pid_pload_pes;
} else {
/* Most probably a SECT packet */
pid_analysis->pload_type = pid_pload_sect;
}
}
/* Unable to determine the payload type, do nothing */
if (pid_analysis->pload_type == pid_pload_unknown)
return;
/* PES packet don't have pointer fields, others do */
if (pusi_flag && pid_analysis->pload_type != pid_pload_pes) {
pointer = tvb_get_guint8(tvb, offset);
pi = proto_tree_add_item(header_tree, hf_mp2t_pointer, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
remaining_len--;
if (pointer > remaining_len) {
/* Bogus pointer */
expert_add_info_format(pinfo, pi, &ei_mp2t_pointer,
"Pointer value is too large (> remaining data length %u)",
remaining_len);
}
}
if (!pinfo->fd->visited) {
/* Get values from our current PID analysis */
frag_cur_pos = pid_analysis->frag_cur_pos;
frag_tot_len = pid_analysis->frag_tot_len;
fragmentation = pid_analysis->fragmentation;
frag_id = pid_analysis->frag_id;
pdata = (packet_analysis_data_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_mp2t, pinfo->curr_layer_num);
if (!pdata) {
pdata = wmem_new0(wmem_file_scope(), packet_analysis_data_t);
pdata->subpacket_table = wmem_tree_new(wmem_file_scope());
/* Since the subpacket data is indexed by offset in the tvb,
* lacking a fragment id transmitted in the protocol,
* we need a different table for each mp2t layer.
*/
p_add_proto_data(wmem_file_scope(), pinfo, proto_mp2t, pinfo->curr_layer_num, pdata);
} else {
spdata = (subpacket_analysis_data_t *)wmem_tree_lookup32(pdata->subpacket_table, offset);
}
if (!spdata) {
spdata = wmem_new0(wmem_file_scope(), subpacket_analysis_data_t);
/* Save the info into pdata from pid_analysis */
spdata->frag_cur_pos = frag_cur_pos;
spdata->frag_tot_len = frag_tot_len;
spdata->fragmentation = fragmentation;
spdata->frag_id = frag_id;
wmem_tree_insert32(pdata->subpacket_table, offset, (void *)spdata);
}
} else {
/* Get saved values */
pdata = (packet_analysis_data_t *)p_get_proto_data(wmem_file_scope(), pinfo, proto_mp2t, pinfo->curr_layer_num);
if (!pdata) {
/* Occurs for the first packets in the capture which cannot be reassembled */
return;
}
spdata = (subpacket_analysis_data_t *)wmem_tree_lookup32(pdata->subpacket_table, offset);
if (!spdata) {
/* Occurs for the first sub packets in the capture which cannot be reassembled */
return;
}
frag_cur_pos = spdata->frag_cur_pos;
frag_tot_len = spdata->frag_tot_len;
fragmentation = spdata->fragmentation;
frag_id = spdata->frag_id;
}
if (frag_tot_len == (guint)-1) {
/* We couldn't determine the total length of the reassembly from
* the first fragment (too short), so get it now that we have the
* second fragment.
*/
frag_tot_len = mp2t_get_packet_length(tvb, offset, pinfo, frag_id, pid_analysis->pload_type);
if (frag_tot_len == (guint)-1) {
/* We still don't have enough to determine the length; this can
* only happen with dropped or out of order packets. Bail out.
* XXX: This just skips the packet and tries the next one, but
* there are probably better ways to handle it, especially if
* the PUSI flag is set in this packet.
*/
return;
}
}
/* The beginning of a new packet is present */
if (pusi_flag) {
if (pointer > remaining_len) {
/*
* Quit, so we don't use the bogus pointer value;
* that could cause remaining_len to become
* "negative", meaning it becomes a very large
* positive value.
*/
return;
}
/* "pointer" contains the number of bytes until the
* start of the new section
*
* if the new section does not start immediately after the
* pointer field (i.e. pointer>0), the remaining bytes before the
* start of the section are another fragment of the
* current packet
*
* if pointer is 0, a new upper-layer packet starts at the
* beginning of this TS packet
* if we have pending fragments, the last TS packet contained the
* last fragment and at the time we processed it, we couldn't figure
* out that it is the last fragment
* this is the case e.g. for PES packets with a 0 length field
* ("unbounded length")
* to handle this case, we add an empty fragment (pointer==0)
* and reassemble, then we process the current TS packet as
* usual
*/
if (fragmentation) {
mp2t_fragment_handle(tvb, offset, pinfo, tree, frag_id, frag_cur_pos,
pointer, TRUE, pid_analysis->pload_type);
frag_id++;
}
offset += pointer;
remaining_len -= pointer;
fragmentation = FALSE;
frag_cur_pos = 0;
frag_tot_len = 0;
if (!remaining_len) {
/* Shouldn't happen */
goto save_state;
}
while (remaining_len > 0) {
/* Don't let subsequent packets overwrite the Info column */
col_append_str(pinfo->cinfo, COL_INFO, " ");
col_set_fence(pinfo->cinfo, COL_INFO);
/* Skip stuff bytes */
stuff_len = 0;
while ((tvb_get_guint8(tvb, offset + stuff_len) == 0xFF)) {
stuff_len++;
if (stuff_len >= remaining_len) {
remaining_len = 0;
break;
}
}
if (stuff_len) {
stuff_tree = proto_tree_add_subtree_format(tree, tvb, offset, stuff_len, ett_stuff, NULL, "Stuffing");
proto_tree_add_item(stuff_tree, hf_mp2t_stuff_bytes, tvb, offset, stuff_len, ENC_NA);
offset += stuff_len;
if (stuff_len >= remaining_len) {
goto save_state;
}
remaining_len -= stuff_len;
}
/* Get the next packet's size if possible */
frag_tot_len = mp2t_get_packet_length(tvb, offset, pinfo, frag_id, pid_analysis->pload_type);
if (frag_tot_len == (guint)-1 || !frag_tot_len) {
mp2t_fragment_handle(tvb, offset, pinfo, tree, frag_id, 0, remaining_len, FALSE, pid_analysis->pload_type);
fragmentation = TRUE;
/*offset += remaining_len;*/
frag_cur_pos += remaining_len;
goto save_state;
}
/* Check for full packets within this TS frame */
if (frag_tot_len &&
frag_tot_len <= remaining_len) {
next_tvb = tvb_new_subset_length(tvb, offset, frag_tot_len);
mp2t_dissect_packet(next_tvb, pid_analysis->pload_type, pinfo, tree);
remaining_len -= frag_tot_len;
offset += frag_tot_len;
frag_tot_len = 0;
frag_id++;
} else {
break;
}
}
if (remaining_len == 0) {
pid_analysis->frag_cur_pos = 0;
pid_analysis->frag_tot_len = 0;
goto save_state;
}
}
/* There are remaining bytes. Add them to the fragment list */
if (frag_tot_len && frag_cur_pos + remaining_len > frag_tot_len) {
/* The case where PUSI was 0, a continuing SECT ended, and stuff
* bytes follow. */
stuff_len = frag_cur_pos + remaining_len - frag_tot_len;
mp2t_fragment_handle(tvb, offset, pinfo, tree, frag_id, frag_cur_pos, remaining_len - stuff_len, TRUE, pid_analysis->pload_type);
offset += remaining_len - stuff_len;
frag_id++;
fragmentation = FALSE;
frag_cur_pos = 0;
frag_tot_len = 0;
stuff_tree = proto_tree_add_subtree_format(tree, tvb, offset, stuff_len, ett_stuff, NULL, "Stuffing");
proto_tree_add_item(stuff_tree, hf_mp2t_stuff_bytes, tvb, offset, stuff_len, ENC_NA);
} else if ((frag_tot_len && frag_cur_pos + remaining_len == frag_tot_len) || (!frag_tot_len && pusi_flag)) {
mp2t_fragment_handle(tvb, offset, pinfo, tree, frag_id, frag_cur_pos, remaining_len, TRUE, pid_analysis->pload_type);
frag_id++;
fragmentation = FALSE;
frag_cur_pos = 0;
frag_tot_len = 0;
} else {
mp2t_fragment_handle(tvb, offset, pinfo, tree, frag_id, frag_cur_pos, remaining_len, FALSE, pid_analysis->pload_type);
fragmentation = TRUE;
frag_cur_pos += remaining_len;
}
/* XXX: Ideally this would be handled with a TRY...FINALLY or
* similar, with more care taken to keep things consistent even
* with fatal errors in subdissectors.
*/
save_state:
pid_analysis->fragmentation = fragmentation;
pid_analysis->frag_cur_pos = frag_cur_pos;
pid_analysis->frag_tot_len = frag_tot_len;
pid_analysis->frag_id = frag_id;
}
/* Calc the number of skipped CC numbers. Note that this can easy
* overflow, and a value above 7 indicate several network packets
* could be lost.
*/
static guint32
calc_skips(gint32 curr, gint32 prev)
{
int res;
/* Only count the missing TS frames in between prev and curr.
* The "prev" frame CC number seen is confirmed received, it's
* the next frames CC counter which is the first known missing
* TS frame
*/
prev += 1;
/* Calc missing TS frame 'skips' */
res = curr - prev;
/* Handle wrap around */
if (res < 0)
res += 16;
return res;
}
#define KEY(pid, cc) ((pid << 4)|cc)
static guint32
detect_cc_drops(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo,
guint32 pid, gint32 cc_curr, mp2t_analysis_data_t *mp2t_data)
{
gint32 cc_prev = -1;
pid_analysis_data_t *pid_data = NULL;
ts_analysis_data_t *ts_data = NULL;
frame_analysis_data_t *frame_analysis_data_p = NULL;
proto_item *flags_item;
gboolean detected_drop = FALSE;
guint32 skips = 0;
/* The initial sequential processing stage */
if (!pinfo->fd->visited) {
/* This is the sequential processing stage */
pid_data = get_pid_analysis(mp2t_data, pid);
cc_prev = pid_data->cc_prev;
pid_data->cc_prev = cc_curr;
/* Null packet always have a CC value equal 0 */
if (pid == 0x1fff)
return 0;
/* Its allowed that (cc_prev == cc_curr) if adaptation field */
if (cc_prev == cc_curr)
return 0;
/* Have not seen this pid before */
if (cc_prev == -1)
return 0;
/* Detect if CC is not increasing by one all the time */
if (cc_curr != ((cc_prev+1) & MP2T_CC_MASK)) {
detected_drop = TRUE;
skips = calc_skips(cc_curr, cc_prev);
mp2t_data->total_skips += skips;
mp2t_data->total_discontinuity++;
/* TODO: if (skips > 7) signal_loss++; ??? */
}
}
/* Save the info about the dropped packet */
if (detected_drop && !pinfo->fd->visited) {
/* Lookup frame data, contains TS pid data objects */
frame_analysis_data_p = get_frame_analysis_data(mp2t_data, pinfo);
if (!frame_analysis_data_p)
frame_analysis_data_p = init_frame_analysis_data(mp2t_data, pinfo);
/* Create and store a new TS frame pid_data object.
This indicate that we have a drop
*/
ts_data = wmem_new0(wmem_file_scope(), struct ts_analysis_data);
ts_data->cc_prev = cc_prev;
ts_data->pid = pid;
ts_data->skips = skips;
wmem_tree_insert32(frame_analysis_data_p->ts_table, KEY(pid, cc_curr),
(void *)ts_data);
}
/* See if we stored info about drops */
if (pinfo->fd->visited) {
/* Lookup frame data, contains TS pid data objects */
frame_analysis_data_p = get_frame_analysis_data(mp2t_data, pinfo);
if (!frame_analysis_data_p)
return 0; /* No stored frame data -> no drops*/
else {
ts_data = (struct ts_analysis_data *)wmem_tree_lookup32(frame_analysis_data_p->ts_table,
KEY(pid, cc_curr));
if (ts_data) {
if (ts_data->skips > 0) {
detected_drop = TRUE;
cc_prev = ts_data->cc_prev;
skips = ts_data->skips;
}
}
}
}
/* Add info to the proto tree about drops */
if (detected_drop) {
expert_add_info_format(pinfo, tree, &ei_mp2t_cc_drop,
"Detected %d missing TS frames before this (last_cc:%d total skips:%d discontinuity:%d)",
skips, cc_prev,
mp2t_data->total_skips,
mp2t_data->total_discontinuity
);
flags_item = proto_tree_add_uint(tree, hf_mp2t_analysis_skips,
tvb, 0, 0, skips);
proto_item_set_generated(flags_item);
flags_item = proto_tree_add_uint(tree, hf_mp2t_analysis_drops,
tvb, 0, 0, 1);
proto_item_set_generated(flags_item);
}
return skips;
}
static gint
dissect_mp2t_adaptation_field(tvbuff_t *tvb, gint offset, proto_tree *tree)
{
gint af_start_offset;
proto_item *hi;
proto_tree *mp2t_af_tree;
guint8 af_length;
guint8 af_flags;
gint stuffing_len;
af_length = tvb_get_guint8(tvb, offset);
proto_tree_add_item(tree, hf_mp2t_af_length, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
/* fix issues where afc==3 but af_length==0
* Adaptaion field...spec section 2.4.3.5: The value 0 is for inserting a single
* stuffing byte in a Transport Stream packet. When the adaptation_field_control
* value is '11', the value of the adaptation_field_length shall be in the range 0 to 182.
*/
if (af_length == 0)
return offset;
af_start_offset = offset;
hi = proto_tree_add_item( tree, hf_mp2t_af, tvb, offset, af_length, ENC_NA);
mp2t_af_tree = proto_item_add_subtree( hi, ett_mp2t_af );
af_flags = tvb_get_guint8(tvb, offset);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_di, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_rai, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_espi, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_pcr_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_opcr_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_sp_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_tpd_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_afe_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
if (af_flags & MP2T_AF_PCR_MASK) {
guint64 pcr_base;
guint16 pcr_ext;
/* 33 bit PCR base, 6 bit reserved, 9 bit PCR ext */
pcr_base = tvb_get_ntoh48(tvb, offset) >> (48-33);
pcr_ext = (guint16)(tvb_get_ntoh48(tvb, offset) & 0x1FF);
proto_tree_add_uint64(mp2t_af_tree, hf_mp2t_af_pcr, tvb, offset, 6,
pcr_base*300 + pcr_ext);
offset += 6;
}
if (af_flags & MP2T_AF_OPCR_MASK) {
guint64 opcr_base;
guint16 opcr_ext;
/* the same format as PCR above */
opcr_base = tvb_get_ntoh48(tvb, offset) >> (48-33);
opcr_ext = (guint16)(tvb_get_ntoh48(tvb, offset) & 0x1FF);
proto_tree_add_uint64(mp2t_af_tree, hf_mp2t_af_opcr, tvb, offset, 6,
opcr_base*300 + opcr_ext);
offset += 6;
}
if (af_flags & MP2T_AF_SP_MASK) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_sc, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
}
if (af_flags & MP2T_AF_TPD_MASK) {
guint8 tpd_len;
tpd_len = tvb_get_guint8(tvb, offset);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_tpd_length, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_tpd, tvb, offset, tpd_len, ENC_NA);
offset += tpd_len;
}
if (af_flags & MP2T_AF_AFE_MASK) {
guint8 e_len;
guint8 e_flags;
gint e_start_offset = offset;
gint reserved_len = 0;
e_len = tvb_get_guint8(tvb, offset);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_length, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
e_flags = tvb_get_guint8(tvb, offset);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_ltw_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_pr_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_ss_flag, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_reserved, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
if (e_flags & MP2T_AF_E_LTW_FLAG_MASK) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_ltwv_flag, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_ltwo, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
if (e_flags & MP2T_AF_E_PR_FLAG_MASK) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_pr_reserved, tvb, offset, 3, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_pr, tvb, offset, 3, ENC_BIG_ENDIAN);
offset += 3;
}
if (e_flags & MP2T_AF_E_SS_FLAG_MASK) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_st, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_dnau_32_30, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_m_1, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_dnau_29_15, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_m_2, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_dnau_14_0, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_m_3, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
}
reserved_len = (e_len + 1) - (offset - e_start_offset);
if (reserved_len > 0) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_e_reserved_bytes, tvb, offset, reserved_len, ENC_NA);
offset += reserved_len;
}
}
stuffing_len = af_length - (offset - af_start_offset);
if (stuffing_len > 0) {
proto_tree_add_item( mp2t_af_tree, hf_mp2t_af_stuffing_bytes, tvb, offset, stuffing_len, ENC_NA);
offset += stuffing_len;
}
return offset;
}
static void
dissect_tsp(tvbuff_t *tvb, gint offset, packet_info *pinfo,
proto_tree *tree, mp2t_analysis_data_t *mp2t_data)
{
guint32 header;
guint afc;
gint start_offset = offset;
gint payload_len;
pid_analysis_data_t *pid_analysis;
guint32 skips;
guint32 pid;
guint32 cc;
guint32 pusi_flag;
guint32 tsc;
proto_item *ti;
proto_item *hi;
proto_item *item = NULL;
proto_tree *mp2t_tree;
proto_tree *mp2t_header_tree;
proto_tree *mp2t_analysis_tree;
proto_item *afci;
ti = proto_tree_add_item( tree, proto_mp2t, tvb, offset, MP2T_PACKET_SIZE, ENC_NA );
mp2t_tree = proto_item_add_subtree( ti, ett_mp2t );
header = tvb_get_ntohl(tvb, offset);
pusi_flag = (header & 0x00400000);
pid = (header & MP2T_PID_MASK) >> MP2T_PID_SHIFT;
tsc = (header & MP2T_TSC_MASK);
afc = (header & MP2T_AFC_MASK) >> MP2T_AFC_SHIFT;
cc = (header & MP2T_CC_MASK) >> MP2T_CC_SHIFT;
proto_item_append_text(ti, " PID=0x%x CC=%d", pid, cc);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "MPEG TS");
hi = proto_tree_add_item( mp2t_tree, hf_mp2t_header, tvb, offset, 4, ENC_BIG_ENDIAN);
mp2t_header_tree = proto_item_add_subtree( hi, ett_mp2t_header );
proto_tree_add_item( mp2t_header_tree, hf_mp2t_sync_byte, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_tei, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_pusi, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_tp, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_pid, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_tsc, tvb, offset, 4, ENC_BIG_ENDIAN);
afci = proto_tree_add_item( mp2t_header_tree, hf_mp2t_afc, tvb, offset, 4, ENC_BIG_ENDIAN);
proto_tree_add_item( mp2t_header_tree, hf_mp2t_cc, tvb, offset, 4, ENC_BIG_ENDIAN);
pid_analysis = get_pid_analysis(mp2t_data, pid);
if (pid_analysis->pload_type == pid_pload_unknown) {
if (pid == MP2T_PID_NULL) {
pid_analysis->pload_type = pid_pload_null;
} else if (pid == MP2T_PID_DOCSIS) {
pid_analysis->pload_type = pid_pload_docsis;
}
}
if (pid_analysis->pload_type == pid_pload_docsis && (afc != 1)) {
/* DOCSIS packets should not have an adaptation field */
if (afc != 1) {
expert_add_info_format(pinfo, afci, &ei_mp2t_invalid_afc,
"Adaptation Field Control for DOCSIS packets must be 0x01");
}
}
if (pid_analysis->pload_type == pid_pload_null) {
col_set_str(pinfo->cinfo, COL_INFO, "NULL packet");
if (afc != 1) {
expert_add_info_format(pinfo, afci, &ei_mp2t_invalid_afc,
"Adaptation Field Control for NULL packets must be 0x01");
}
/* Nothing more to do */
return;
}
offset += 4;
/* Create a subtree for analysis stuff */
mp2t_analysis_tree = proto_tree_add_subtree_format(mp2t_tree, tvb, offset, 0, ett_mp2t_analysis, &item, "MPEG2 PCR Analysis");
proto_item_set_generated(item);
skips = detect_cc_drops(tvb, mp2t_analysis_tree, pinfo, pid, cc, mp2t_data);
if (skips > 0)
proto_item_append_text(ti, " skips=%d", skips);
if (afc == 2 || afc == 3)
offset = dissect_mp2t_adaptation_field(tvb, offset, mp2t_tree);
if ((offset - start_offset) < MP2T_PACKET_SIZE)
payload_len = MP2T_PACKET_SIZE - (offset - start_offset);
else
payload_len = 0;
if (!payload_len)
return;
if (afc == 2) {
col_set_str(pinfo->cinfo, COL_INFO, "Adaptation field only");
/* The rest of the packet is stuffing bytes */
proto_tree_add_item( mp2t_tree, hf_mp2t_stuff_bytes, tvb, offset, payload_len, ENC_NA);
offset += payload_len;
}
if (!tsc) {
mp2t_process_fragmented_payload(tvb, offset, payload_len, pinfo, tree, mp2t_tree, pusi_flag, pid_analysis);
} else {
/* Payload is scrambled */
col_set_str(pinfo->cinfo, COL_INFO, "Scrambled TS payload");
}
}
static int
dissect_mp2t( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_ )
{
volatile guint offset = 0;
conversation_t *conv;
mp2t_stream_key *stream;
mp2t_analysis_data_t *mp2t_data;
const char *saved_proto;
conv = find_or_create_conversation(pinfo);
stream = wmem_new(pinfo->pool, mp2t_stream_key);
stream->conv = conv;
/* Conversations on UDP, etc. are bidirectional, but in the odd case
* that we have two MP2T streams in the opposite directions, we have to
* separately track their Continuity Counters, manage their fragmentation
* status information, etc.
*/
if (addresses_equal(&pinfo->src, conversation_key_addr1(conv->key_ptr))) {
stream->dir = P2P_DIR_SENT;
} else if (addresses_equal(&pinfo->dst, conversation_key_addr1(conv->key_ptr))) {
stream->dir = P2P_DIR_RECV;
} else {
/* DVB Base Band Frames, or some other endpoint that doesn't set the
* address, presumably unidirectional.
*/
stream->dir = P2P_DIR_SENT;
}
p_add_proto_data(pinfo->pool, pinfo, proto_mp2t, MP2T_PROTO_DATA_STREAM, stream);
for (; tvb_reported_length_remaining(tvb, offset) >= MP2T_PACKET_SIZE; offset += MP2T_PACKET_SIZE) {
/*
* Dissect the TSP.
*
* If it gets an error that means there's no point in
* dissecting any more TSPs, rethrow the exception in
* question.
*
* If it gets any other error, report it and continue, as that
* means that TSP got an error, but that doesn't mean we should
* stop dissecting TSPs within this frame or chunk of reassembled
* data.
*/
saved_proto = pinfo->current_proto;
TRY {
mp2t_data = get_mp2t_conversation_data(stream);
dissect_tsp(tvb, offset, pinfo, tree, mp2t_data);
}
CATCH_NONFATAL_ERRORS {
show_exception(tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
/*
* Restore the saved protocol as well; we do this after
* show_exception(), so that the "Malformed packet" indication
* shows the protocol for which dissection failed.
*/
pinfo->current_proto = saved_proto;
}
ENDTRY;
}
return tvb_captured_length(tvb);
}
static gboolean
heur_dissect_mp2t( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_ )
{
gint length;
guint offset = 0;
length = tvb_reported_length_remaining(tvb, offset);
if (length == 0) {
/* Nothing to check for */
return FALSE;
}
if ((length % MP2T_PACKET_SIZE) != 0) {
/* Not a multiple of the MPEG-2 transport packet size */
return FALSE;
} else {
while (tvb_offset_exists(tvb, offset)) {
if (tvb_get_guint8(tvb, offset) != MP2T_SYNC_BYTE) {
/* No sync byte at the appropriate offset */
return FALSE;
}
offset += MP2T_PACKET_SIZE;
}
}
dissect_mp2t(tvb, pinfo, tree, data);
return TRUE;
}
void
proto_register_mp2t(void)
{
static hf_register_info hf[] = {
{ &hf_mp2t_header, {
"Header", "mp2t.header",
FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_sync_byte, {
"Sync Byte", "mp2t.sync_byte",
FT_UINT32, BASE_HEX, VALS(mp2t_sync_byte_vals), MP2T_SYNC_BYTE_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_tei, {
"Transport Error Indicator", "mp2t.tei",
FT_UINT32, BASE_DEC, NULL, MP2T_TEI_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_pusi, {
"Payload Unit Start Indicator", "mp2t.pusi",
FT_UINT32, BASE_DEC, NULL, MP2T_PUSI_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_tp, {
"Transport Priority", "mp2t.tp",
FT_UINT32, BASE_DEC, NULL, MP2T_TP_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_pid, {
"PID", "mp2t.pid",
FT_UINT32, BASE_HEX, VALS(mp2t_pid_vals), MP2T_PID_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_tsc, {
"Transport Scrambling Control", "mp2t.tsc",
FT_UINT32, BASE_HEX, VALS(mp2t_tsc_vals), MP2T_TSC_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_afc, {
"Adaptation Field Control", "mp2t.afc",
FT_UINT32, BASE_HEX, VALS(mp2t_afc_vals) , MP2T_AFC_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_cc, {
"Continuity Counter", "mp2t.cc",
FT_UINT32, BASE_DEC, NULL, MP2T_CC_MASK, NULL, HFILL
} } ,
#if 0
{ &hf_mp2t_analysis_flags, {
"MPEG2-TS Analysis Flags", "mp2t.analysis.flags",
FT_NONE, BASE_NONE, NULL, 0x0,
"This frame has some of the MPEG2 analysis flags set", HFILL
} } ,
#endif
{ &hf_mp2t_analysis_skips, {
"TS Continuity Counter Skips", "mp2t.analysis.skips",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Missing TS frames according to CC counter values", HFILL
} } ,
{ &hf_mp2t_analysis_drops, {
"Some frames dropped", "mp2t.analysis.drops",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Discontinuity: A number of TS frames were dropped", HFILL
} } ,
{ &hf_mp2t_af, {
"Adaptation Field", "mp2t.af",
FT_NONE, BASE_NONE, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_length, {
"Adaptation Field Length", "mp2t.af.length",
FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL
} } ,
{ &hf_mp2t_af_di, {
"Discontinuity Indicator", "mp2t.af.di",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_DI_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_rai, {
"Random Access Indicator", "mp2t.af.rai",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_RAI_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_espi, {
"Elementary Stream Priority Indicator", "mp2t.af.espi",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_ESPI_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_pcr_flag, {
"PCR Flag", "mp2t.af.pcr_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_PCR_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_opcr_flag, {
"OPCR Flag", "mp2t.af.opcr_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_OPCR_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_sp_flag, {
"Splicing Point Flag", "mp2t.af.sp_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_SP_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_tpd_flag, {
"Transport Private Data Flag", "mp2t.af.tpd_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_TPD_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_afe_flag, {
"Adaptation Field Extension Flag", "mp2t.af.afe_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_AFE_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_pcr, {
"Program Clock Reference", "mp2t.af.pcr",
FT_UINT64, BASE_HEX, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_opcr, {
"Original Program Clock Reference", "mp2t.af.opcr",
FT_UINT64, BASE_HEX, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_sc, {
"Splice Countdown", "mp2t.af.sc",
FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_tpd_length, {
"Transport Private Data Length", "mp2t.af.tpd_length",
FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_tpd, {
"Transport Private Data", "mp2t.af.tpd",
FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_length, {
"Adaptation Field Extension Length", "mp2t.af.e_length",
FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_ltw_flag, {
"LTW Flag", "mp2t.af.e.ltw_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_E_LTW_FLAG_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_pr_flag, {
"Piecewise Rate Flag", "mp2t.af.e.pr_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_E_PR_FLAG_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_ss_flag, {
"Seamless Splice Flag", "mp2t.af.e.ss_flag",
FT_UINT8, BASE_DEC, NULL, MP2T_AF_E_SS_FLAG_MASK, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_reserved, {
"Reserved", "mp2t.af.e.reserved",
FT_UINT8, BASE_DEC, NULL, 0x1F, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_reserved_bytes, {
"Reserved", "mp2t.af.e.reserved_bytes",
FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL
} } ,
{ &hf_mp2t_af_stuffing_bytes, {
"Stuffing", "mp2t.af.stuffing_bytes",
FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_ltwv_flag, {
"LTW Valid Flag", "mp2t.af.e.ltwv_flag",
FT_UINT16, BASE_DEC, NULL, 0x8000, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_ltwo, {
"LTW Offset", "mp2t.af.e.ltwo",
FT_UINT16, BASE_DEC, NULL, 0x7FFF, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_pr_reserved, {
"Reserved", "mp2t.af.e.pr_reserved",
FT_UINT24, BASE_DEC, NULL, 0xC00000, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_pr, {
"Piecewise Rate", "mp2t.af.e.pr",
FT_UINT24, BASE_DEC, NULL, 0x3FFFFF, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_st, {
"Splice Type", "mp2t.af.e.st",
FT_UINT8, BASE_DEC, NULL, 0xF0, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_dnau_32_30, {
"DTS Next AU[32...30]", "mp2t.af.e.dnau_32_30",
FT_UINT8, BASE_DEC, NULL, 0x0E, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_m_1, {
"Marker Bit", "mp2t.af.e.m_1",
FT_UINT8, BASE_DEC, NULL, 0x01, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_dnau_29_15, {
"DTS Next AU[29...15]", "mp2t.af.e.dnau_29_15",
FT_UINT16, BASE_DEC, NULL, 0xFFFE, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_m_2, {
"Marker Bit", "mp2t.af.e.m_2",
FT_UINT16, BASE_DEC, NULL, 0x0001, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_dnau_14_0, {
"DTS Next AU[14...0]", "mp2t.af.e.dnau_14_0",
FT_UINT16, BASE_DEC, NULL, 0xFFFE, NULL, HFILL
} } ,
{ &hf_mp2t_af_e_m_3, {
"Marker Bit", "mp2t.af.e.m_3",
FT_UINT16, BASE_DEC, NULL, 0x0001, NULL, HFILL
} } ,
#if 0
{ &hf_mp2t_payload, {
"Payload", "mp2t.payload",
FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL
} } ,
#endif
{ &hf_mp2t_stuff_bytes, {
"Stuffing", "mp2t.stuff_bytes",
FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL
} },
{ &hf_mp2t_pointer, {
"Pointer", "mp2t.pointer",
FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL
} },
{ &hf_msg_fragments, {
"Message fragments", "mp2t.msg.fragments",
FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment, {
"Message fragment", "mp2t.msg.fragment",
FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_overlap, {
"Message fragment overlap", "mp2t.msg.fragment.overlap",
FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_overlap_conflicts, {
"Message fragment overlapping with conflicting data",
"mp2t.msg.fragment.overlap.conflicts",
FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_multiple_tails, {
"Message has multiple tail fragments",
"mp2t.msg.fragment.multiple_tails",
FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_too_long_fragment, {
"Message fragment too long", "mp2t.msg.fragment.too_long_fragment",
FT_BOOLEAN, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_error, {
"Message defragmentation error", "mp2t.msg.fragment.error",
FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_fragment_count, {
"Message fragment count", "mp2t.msg.fragment.count",
FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_reassembled_in, {
"Reassembled in", "mp2t.msg.reassembled.in",
FT_FRAMENUM, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_reassembled_length, {
"Reassembled MP2T length", "mp2t.msg.reassembled.length",
FT_UINT32, BASE_DEC, NULL, 0x00, NULL, HFILL
} },
{ &hf_msg_ts_packet_reassembled, {
"MPEG TS Packet (reassembled)", "mp2t.ts_packet_reassembled",
FT_NONE, BASE_NONE, NULL, 0x00, NULL, HFILL
} },
};
static gint *ett[] =
{
&ett_mp2t,
&ett_mp2t_header,
&ett_mp2t_af,
&ett_mp2t_analysis,
&ett_stuff,
&ett_msg_fragment,
&ett_msg_fragments
};
static ei_register_info ei[] = {
{ &ei_mp2t_pointer, { "mp2t.pointer_too_large", PI_MALFORMED, PI_ERROR, "Pointer value is too large", EXPFILL }},
{ &ei_mp2t_cc_drop, { "mp2t.cc.drop", PI_SEQUENCE, PI_ERROR, "Detected missing TS frames", EXPFILL }},
{ &ei_mp2t_invalid_afc, { "mp2t.afc.invalid", PI_PROTOCOL, PI_WARN,
"Adaptation Field Control contains an invalid value", EXPFILL }}
};
expert_module_t* expert_mp2t;
proto_mp2t = proto_register_protocol("ISO/IEC 13818-1", "MP2T", "mp2t");
mp2t_handle = register_dissector("mp2t", dissect_mp2t, proto_mp2t);
proto_register_field_array(proto_mp2t, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_mp2t = expert_register_protocol(proto_mp2t);
expert_register_field_array(expert_mp2t, ei, array_length(ei));
heur_subdissector_list = register_heur_dissector_list("mp2t.pid", proto_mp2t);
/* Register init of processing of fragmented DEPI packets */
reassembly_table_register(&mp2t_reassembly_table,
&mp2t_reassembly_table_functions);
mp2t_stream_hashtable = wmem_map_new_autoreset(wmem_epan_scope(), wmem_file_scope(), mp2t_stream_hash, mp2t_stream_equal);
}
void
proto_reg_handoff_mp2t(void)
{
heur_dissector_add("udp", heur_dissect_mp2t, "MP2T over UDP", "mp2t_udp", proto_mp2t, HEURISTIC_ENABLE);
dissector_add_uint("rtp.pt", PT_MP2T, mp2t_handle);
dissector_add_for_decode_as_with_preference("tcp.port", mp2t_handle);
dissector_add_for_decode_as_with_preference("udp.port", mp2t_handle);
heur_dissector_add("usb.bulk", heur_dissect_mp2t, "MP2T USB bulk endpoint", "mp2t_usb_bulk", proto_mp2t, HEURISTIC_ENABLE);
dissector_add_uint("wtap_encap", WTAP_ENCAP_MPEG_2_TS, mp2t_handle);
dissector_add_uint("l2tp.pw_type", L2TPv3_PROTOCOL_DOCSIS_DMPT, mp2t_handle);
dissector_add_string("media_type", "video/mp2t", mp2t_handle);
docsis_handle = find_dissector("docsis");
mpeg_pes_handle = find_dissector("mpeg-pes");
mpeg_sect_handle = find_dissector("mpeg_sect");
}
/*
* 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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