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RTP processing: Modified RTP sequence verification 

The patch changes:
- Removed first_packet_mac_addr staff. It was commented out many years ago...
- Removed delta_timestamp item. Not used.
- Sequence verification takes into account timestamp therefore it is able to detect delayed packets more clearly. As consequence of it, #16330 is solved.
- If packet is delayed, it is not used in calculation of diff/jitter/skew. It just mess output. As consequence of it, #16330 is solved.

I checked output with many RTP streams and looks well. But I have no
sample with wrapped timestamp and I have just a few samples with
missing/reordered packets. Nevertheless all are calculated same way as
before and #16330 is solved too.
This commit is contained in:
Jirka Novak 2021-01-03 08:03:46 +01:00 committed by AndersBroman
parent 85deb99637
commit 7928f81b10
3 changed files with 103 additions and 85 deletions
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182
ui/tap-rtp-analysis.c
View File

@ -156,6 +156,8 @@ get_dyn_pt_clock_rate(const gchar *payload_type_str)
return 0;
}
#define TIMESTAMP_DIFFERENCE(v1,v2) ((gint64)v2-(gint64)v1)
/****************************************************************************/
void
rtppacket_analyse(tap_rtp_stat_t *statinfo,
@ -170,6 +172,7 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
double expected_time;
double absskew;
guint32 clock_rate;
gboolean in_time_sequence;
/* Store the current time */
current_time = nstime_to_msec(&pinfo->rel_ts);
@ -177,9 +180,6 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
/* Is this the first packet we got in this direction? */
if (statinfo->first_packet) {
/* Save the MAC address of the first RTP frame */
if( pinfo->dl_src.type == AT_ETHER){
copy_address(&(statinfo->first_packet_mac_addr), &(pinfo->dl_src));
}
statinfo->start_seq_nr = rtpinfo->info_seq_num;
statinfo->stop_seq_nr = rtpinfo->info_seq_num;
statinfo->seq_num = rtpinfo->info_seq_num;
@ -220,23 +220,10 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
/* Reset flags */
statinfo->flags = 0;
#if 0
/*According to bug https://gitlab.com/wireshark/wireshark/-/issues/11478
* this code causes problems. A better solution is needed if there is need for the functionality */
/* Try to detect duplicated packets due to mirroring/span ports by comparing src MAC addresses.
* Check for duplicates (src mac differs from first_packet_mac_addr) */
*/
if( pinfo->dl_src.type == AT_ETHER){
if(!addresses_equal(&(statinfo->first_packet_mac_addr), &(pinfo->dl_src))){
statinfo->flags |= STAT_FLAG_DUP_PKT;
statinfo->delta = current_time-(statinfo->time);
return;
}
}
#endif
/* When calculating expected rtp packets the seq number can wrap around
* so we have to count the number of cycles
* Variable cycles counts the wraps around in forwarding connection and
* Variable seq_cycles counts the wraps around in forwarding connection and
* under is flag that indicates where we are
*
* XXX How to determine number of cycles with all possible lost, late
@ -248,11 +235,32 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
* where below code won't work correctly - statistic may be wrong then.
*/
/* Check if time sequence of packets is in order. We check whether
* timestamp difference is below 1/2 of timestamp range (hours or days).
* Packets can be in pure sequence or sequence can be wrapped arround
* 0xFFFFFFFF.
*/
if ((statinfo->first_timestamp <= rtpinfo->info_timestamp) &&
TIMESTAMP_DIFFERENCE(statinfo->first_timestamp, rtpinfo->info_timestamp) < 0x80000000) {
// Normal timestamp sequence
in_time_sequence = TRUE;
} else if ((statinfo->first_timestamp > rtpinfo->info_timestamp) &&
(TIMESTAMP_DIFFERENCE(0x00000000,statinfo->first_timestamp) + TIMESTAMP_DIFFERENCE(rtpinfo->info_timestamp, 0xFFFFFFFF)) < 0x80000000) {
// Normal timestamp sequence with wraparound
in_time_sequence = TRUE;
} else {
// New packet is not in sequence (is in past)
in_time_sequence = FALSE;
statinfo->flags |= STAT_FLAG_WRONG_TIMESTAMP;
}
/* So if the current sequence number is less than the start one
* we assume, that there is another cycle running
*/
if ((rtpinfo->info_seq_num < statinfo->start_seq_nr) && (statinfo->under == FALSE)){
statinfo->cycles++;
if ((rtpinfo->info_seq_num < statinfo->start_seq_nr) &&
in_time_sequence &&
(statinfo->under == FALSE)) {
statinfo->seq_cycles++;
statinfo->under = TRUE;
}
/* what if the start seq nr was 0? Then the above condition will never
@ -260,12 +268,15 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
* if one of the packets with seq nr 0 or 65535 would be lost or late
*/
else if ((rtpinfo->info_seq_num == 0) && (statinfo->stop_seq_nr == 65535) &&
(statinfo->under == FALSE)) {
statinfo->cycles++;
in_time_sequence &&
(statinfo->under == FALSE)) {
statinfo->seq_cycles++;
statinfo->under = TRUE;
}
/* the whole round is over, so reset the flag */
else if ((rtpinfo->info_seq_num > statinfo->start_seq_nr) && (statinfo->under != FALSE)) {
else if ((rtpinfo->info_seq_num > statinfo->start_seq_nr) &&
in_time_sequence &&
(statinfo->under != FALSE)) {
statinfo->under = FALSE;
}
@ -276,17 +287,25 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
/* If the current seq number equals the last one or if we are here for
* the first time, then it is ok, we just store the current one as the last one
*/
if ( (statinfo->seq_num+1 == rtpinfo->info_seq_num) || (statinfo->flags & STAT_FLAG_FIRST) )
if ( in_time_sequence &&
( (statinfo->seq_num+1 == rtpinfo->info_seq_num) || (statinfo->flags & STAT_FLAG_FIRST) )
) {
statinfo->seq_num = rtpinfo->info_seq_num;
}
/* If the first one is 65535 we wrap */
else if ( (statinfo->seq_num == 65535) && (rtpinfo->info_seq_num == 0) )
else if ( in_time_sequence &&
( (statinfo->seq_num == 65535) && (rtpinfo->info_seq_num == 0) )
) {
statinfo->seq_num = rtpinfo->info_seq_num;
}
/* Lost packets. If the prev seq is enormously larger than the cur seq
* we assume that instead of being massively late we lost the packet(s)
* that would have indicated the sequence number wrapping. An imprecise
* heuristic at best, but it seems to work well enough.
* https://gitlab.com/wireshark/wireshark/-/issues/5958 */
else if (statinfo->seq_num+1 < rtpinfo->info_seq_num || statinfo->seq_num - rtpinfo->info_seq_num > 0xFF00) {
else if ( in_time_sequence &&
(statinfo->seq_num+1 < rtpinfo->info_seq_num || statinfo->seq_num - rtpinfo->info_seq_num > 0xFF00)
) {
statinfo->seq_num = rtpinfo->info_seq_num;
statinfo->sequence++;
statinfo->flags |= STAT_FLAG_WRONG_SEQ;
@ -336,56 +355,60 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
}
}
/* Handle wraparound ? */
arrivaltime = current_time - statinfo->start_time;
/* diff/jitter/skew calculations are done just for in sequence packets */
if ( in_time_sequence ) {
nominaltime = (double)(guint32_wraparound_diff(rtpinfo->info_timestamp, statinfo->first_timestamp));
/* Handle wraparound ? */
arrivaltime = current_time - statinfo->start_time;
/* Can only analyze defined sampling rates */
if (clock_rate != 0) {
statinfo->clock_rate = clock_rate;
/* Convert from sampling clock to ms */
nominaltime = nominaltime /(clock_rate/1000);
nominaltime = (double)(guint32_wraparound_diff(rtpinfo->info_timestamp, statinfo->first_timestamp));
/* Calculate the current jitter(in ms) */
if (!statinfo->first_packet) {
expected_time = statinfo->time + (nominaltime - statinfo->lastnominaltime);
current_diff = fabs(current_time - expected_time);
current_jitter = (15 * statinfo->jitter + current_diff) / 16;
/* Can only analyze defined sampling rates */
if (clock_rate != 0) {
statinfo->clock_rate = clock_rate;
/* Convert from sampling clock to ms */
nominaltime = nominaltime /(clock_rate/1000);
statinfo->delta = current_time-(statinfo->time);
statinfo->jitter = current_jitter;
statinfo->diff = current_diff;
}
statinfo->lastnominaltime = nominaltime;
/* Calculate skew, i.e. absolute jitter that also catches clock drift
* Skew is positive if TS (nominal) is too fast
*/
statinfo->skew = nominaltime - arrivaltime;
absskew = fabs(statinfo->skew);
if(absskew > fabs(statinfo->max_skew)) {
statinfo->max_skew = statinfo->skew;
}
/* Gather data for calculation of average, minimum and maximum framerate based on timestamp */
#if 0
if (numPackets > 0 && (!hardPayloadType || !alternatePayloadType)) {
/* Skip first packet and possibly alternate payload type packets */
double dt;
dt = nominaltime - statinfo->lastnominaltime;
sumdt += 1.0 * dt;
numdt += (dt != 0 ? 1 : 0);
mindt = (dt < mindt ? dt : mindt);
maxdt = (dt > maxdt ? dt : maxdt);
}
#endif
/* Gather data for calculation of skew least square */
statinfo->sumt += 1.0 * arrivaltime;
statinfo->sumTS += 1.0 * nominaltime;
statinfo->sumt2 += 1.0 * arrivaltime * arrivaltime;
statinfo->sumtTS += 1.0 * arrivaltime * nominaltime;
} else {
if (!statinfo->first_packet) {
statinfo->delta = current_time-(statinfo->time);
/* Calculate the current jitter(in ms) */
if (!statinfo->first_packet) {
expected_time = statinfo->time + (nominaltime - statinfo->lastnominaltime);
current_diff = fabs(current_time - expected_time);
current_jitter = (15 * statinfo->jitter + current_diff) / 16;
statinfo->delta = current_time-(statinfo->time);
statinfo->jitter = current_jitter;
statinfo->diff = current_diff;
}
statinfo->lastnominaltime = nominaltime;
/* Calculate skew, i.e. absolute jitter that also catches clock drift
* Skew is positive if TS (nominal) is too fast
*/
statinfo->skew = nominaltime - arrivaltime;
absskew = fabs(statinfo->skew);
if (absskew > fabs(statinfo->max_skew)) {
statinfo->max_skew = statinfo->skew;
}
/* Gather data for calculation of average, minimum and maximum framerate based on timestamp */
#if 0
if (numPackets > 0 && (!hardPayloadType || !alternatePayloadType)) {
/* Skip first packet and possibly alternate payload type packets */
double dt;
dt = nominaltime - statinfo->lastnominaltime;
sumdt += 1.0 * dt;
numdt += (dt != 0 ? 1 : 0);
mindt = (dt < mindt ? dt : mindt);
maxdt = (dt > maxdt ? dt : maxdt);
}
#endif
/* Gather data for calculation of skew least square */
statinfo->sumt += 1.0 * arrivaltime;
statinfo->sumTS += 1.0 * nominaltime;
statinfo->sumt2 += 1.0 * arrivaltime * arrivaltime;
statinfo->sumtTS += 1.0 * arrivaltime * nominaltime;
} else {
if (!statinfo->first_packet) {
statinfo->delta = current_time-(statinfo->time);
}
}
}
@ -414,19 +437,11 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
if (statinfo->bw_index == BUFF_BW) statinfo->bw_index = 0;
/* Used by GTK code only */
statinfo->delta_timestamp = guint32_wraparound_diff(rtpinfo->info_timestamp, statinfo->timestamp);
/* Is it a packet with the mark bit set? */
if (rtpinfo->info_marker_set) {
statinfo->flags |= STAT_FLAG_MARKER;
}
/* Difference can be negative. We don't expect difference bigger than 31 bits. Difference don't care about wrap around. */
gint32 tsdelta=rtpinfo->info_timestamp - statinfo->timestamp;
if (tsdelta < 0) {
statinfo->flags |= STAT_FLAG_WRONG_TIMESTAMP;
}
/* Is it a regular packet? */
if (!(statinfo->flags & STAT_FLAG_FIRST)
&& !(statinfo->flags & STAT_FLAG_MARKER)
@ -460,7 +475,12 @@ rtppacket_analyse(tap_rtp_stat_t *statinfo,
statinfo->reg_pt = statinfo->pt;
}
statinfo->time = current_time;
if (in_time_sequence) {
/* We remember last time just for in_time sequence packets
* therefore diff calculations are correct for it
*/
statinfo->time = current_time;
}
statinfo->timestamp = rtpinfo->info_timestamp;
statinfo->stop_seq_nr = rtpinfo->info_seq_num;
statinfo->total_nr++;

4
ui/tap-rtp-analysis.h
View File

@ -45,12 +45,10 @@ typedef struct _tap_rtp_stat_t {
/* all of the following fields will be initialized after
* rtppacket_analyse has been called
*/
address first_packet_mac_addr; /**< MAC address of first packet, used to determine duplicates due to mirroring */
guint32 flags; /* see STAT_FLAG-defines below */
guint16 seq_num;
guint32 timestamp;
guint32 first_timestamp;
guint32 delta_timestamp;
double bandwidth;
bw_history_item bw_history[BUFF_BW];
guint16 bw_start_index;
@ -78,7 +76,7 @@ typedef struct _tap_rtp_stat_t {
guint32 total_nr;
guint32 sequence;
gboolean under;
gint cycles;
gint seq_cycles;
guint16 pt;
int reg_pt;
guint32 first_packet_num;

2
ui/tap-rtp-common.c
View File

@ -487,7 +487,7 @@ void rtpstream_info_calculate(const rtpstream_info_t *strinfo, rtpstream_info_ca
calc->packet_count = strinfo->packet_count;
/* packet count, lost packets */
calc->packet_expected = (strinfo->rtp_stats.stop_seq_nr + strinfo->rtp_stats.cycles*65536)
calc->packet_expected = (strinfo->rtp_stats.stop_seq_nr + strinfo->rtp_stats.seq_cycles*0x10000)
- strinfo->rtp_stats.start_seq_nr + 1;
calc->total_nr = strinfo->rtp_stats.total_nr;
calc->lost_num = calc->packet_expected - strinfo->rtp_stats.total_nr;