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rtcp.c
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rtcp.c
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/*! \file rtcp.c
* \author Lorenzo Miniero <[email protected]>
* \copyright GNU General Public License v3
* \brief RTCP processing
* \details Implementation (based on the oRTP structures) of the RTCP
* messages. RTCP messages coming through the gateway are parsed and,
* if needed (according to http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00),
* fixed before they are sent to the peers (e.g., to fix SSRCs that may
* have been changed by the gateway). Methods to generate FIR messages
* and generate/cap REMB messages are provided as well.
*
* \ingroup protocols
* \ref protocols
*/
#include <math.h>
#include <stdlib.h>
#include <sys/time.h>
#include "debug.h"
#include "rtp.h"
#include "rtcp.h"
#include "utils.h"
int janus_rtcp_parse(janus_rtcp_context *ctx, char *packet, int len) {
return janus_rtcp_fix_ssrc(ctx, packet, len, 0, 0, 0);
}
guint32 janus_rtcp_get_sender_ssrc(char *packet, int len) {
if(packet == NULL || len == 0)
return 0;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return 0;
int pno = 0, total = len;
while(rtcp) {
pno++;
switch(rtcp->type) {
case RTCP_SR: {
/* SR, sender report */
janus_rtcp_sr *sr = (janus_rtcp_sr *)rtcp;
return ntohl(sr->ssrc);
}
case RTCP_RR: {
/* RR, receiver report */
janus_rtcp_rr *rr = (janus_rtcp_rr *)rtcp;
return ntohl(rr->ssrc);
}
case RTCP_RTPFB: {
/* RTPFB, Transport layer FB message (rfc4585) */
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
return ntohl(rtcpfb->ssrc);
}
case RTCP_PSFB: {
/* PSFB, Payload-specific FB message (rfc4585) */
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
return ntohl(rtcpfb->ssrc);
}
case RTCP_XR: {
/* XR, extended reports (rfc3611) */
janus_rtcp_xr *xr = (janus_rtcp_xr *)rtcp;
return ntohl(xr->ssrc);
}
default:
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0) {
break;
}
total -= length*4+4;
if(total <= 0) {
break;
}
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return 0;
}
guint32 janus_rtcp_get_receiver_ssrc(char *packet, int len) {
if(packet == NULL || len == 0)
return 0;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return 0;
int pno = 0, total = len;
while(rtcp) {
pno++;
switch(rtcp->type) {
case RTCP_SR: {
/* SR, sender report */
janus_rtcp_sr *sr = (janus_rtcp_sr *)rtcp;
if(sr->header.rc > 0) {
return ntohl(sr->rb[0].ssrc);
}
break;
}
case RTCP_RR: {
/* RR, receiver report */
janus_rtcp_rr *rr = (janus_rtcp_rr *)rtcp;
if(rr->header.rc > 0) {
return ntohl(rr->rb[0].ssrc);
}
break;
}
default:
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0) {
break;
}
total -= length*4+4;
if(total <= 0) {
break;
}
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return 0;
}
/* Helper to handle an incoming SR: triggered by a call to janus_rtcp_fix_ssrc with fixssrc=0 */
static void janus_rtcp_incoming_sr(janus_rtcp_context *ctx, janus_rtcp_sr *sr) {
if(ctx == NULL)
return;
/* Update the context with info on the monotonic time of last SR received */
ctx->lsr_ts = janus_get_monotonic_time();
/* Compute the last SR received as well */
uint64_t ntp = ntohl(sr->si.ntp_ts_msw);
ntp = (ntp << 32) | ntohl(sr->si.ntp_ts_lsw);
ctx->lsr = (ntp >> 16);
}
/* Helper to handle an incoming RR: triggered by a call to janus_rtcp_fix_ssrc with fixssrc=0 */
static void janus_rtcp_incoming_rr(janus_rtcp_context *ctx, janus_rtcp_rr *rr) {
if(ctx == NULL)
return;
/* FIXME Check the Record Blocks */
if(rr->header.rc > 0) {
double jitter = (double)ntohl(rr->rb[0].jitter);
uint32_t fraction = ntohl(rr->rb[0].flcnpl) >> 24;
uint32_t total = ntohl(rr->rb[0].flcnpl) & 0x00FFFFFF;
JANUS_LOG(LOG_HUGE, "jitter=%f, fraction=%"SCNu32", loss=%"SCNu32"\n", jitter, fraction, total);
ctx->lost_remote = total;
ctx->jitter_remote = jitter;
/* FIXME Compute round trip time */
uint32_t lsr = ntohl(rr->rb[0].lsr);
uint32_t dlsr = ntohl(rr->rb[0].delay);
if(lsr == 0) /* Not enough info yet */
return;
struct timeval tv;
gettimeofday(&tv, NULL);
uint32_t s = tv.tv_sec + 2208988800u;
uint32_t u = tv.tv_usec;
uint32_t f = (u << 12) + (u << 8) - ((u * 3650) >> 6);
uint32_t ntp_ts_msw = htonl(s);
uint32_t ntp_ts_lsw = htonl(f);
uint64_t temp = ntohl(ntp_ts_msw);
temp = (temp << 32) | ntohl(ntp_ts_lsw);
uint32_t a = (uint32_t)(temp >> 16);
uint32_t rtt = a - lsr - dlsr;
uint32_t rtt_msw = (rtt & 0xFFFF0000) >> 16;
uint32_t rtt_lsw = (rtt & 0x0000FFFF) << 16;
tv.tv_sec = rtt_msw;
tv.tv_usec = ((rtt_lsw << 6) / 3650) - (rtt_lsw >> 12) - (rtt_lsw >> 8);
ctx->rtt = tv.tv_sec + tv.tv_usec / 1000; /* We need milliseconds */
}
}
int janus_rtcp_fix_ssrc(janus_rtcp_context *ctx, char *packet, int len, int fixssrc, uint32_t newssrcl, uint32_t newssrcr) {
if(packet == NULL || len <= 0)
return -1;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return -2;
int pno = 0, total = len;
JANUS_LOG(LOG_HUGE, " Parsing compound packet (total of %d bytes)\n", total);
while(rtcp) {
pno++;
/* TODO Should we handle any of these packets ourselves, or just relay them? */
switch(rtcp->type) {
case RTCP_SR: {
/* SR, sender report */
JANUS_LOG(LOG_HUGE, " #%d SR (200)\n", pno);
janus_rtcp_sr *sr = (janus_rtcp_sr *)rtcp;
/* If an RTCP context was provided, update it with info on this SR */
janus_rtcp_incoming_sr(ctx, sr);
if(fixssrc && newssrcl) {
sr->ssrc = htonl(newssrcl);
}
if(fixssrc && newssrcr && sr->header.rc > 0) {
sr->rb[0].ssrc = htonl(newssrcr);
}
break;
}
case RTCP_RR: {
/* RR, receiver report */
JANUS_LOG(LOG_HUGE, " #%d RR (201)\n", pno);
janus_rtcp_rr *rr = (janus_rtcp_rr *)rtcp;
/* If an RTCP context was provided, update it with info on this RR */
janus_rtcp_incoming_rr(ctx, rr);
if(fixssrc && newssrcl) {
rr->ssrc = htonl(newssrcl);
}
if(fixssrc && newssrcr && rr->header.rc > 0) {
rr->rb[0].ssrc = htonl(newssrcr);
}
break;
}
case RTCP_SDES: {
/* SDES, source description */
JANUS_LOG(LOG_HUGE, " #%d SDES (202)\n", pno);
janus_rtcp_sdes *sdes = (janus_rtcp_sdes *)rtcp;
//~ JANUS_LOG(LOG_HUGE, " -- SSRC: %u\n", ntohl(sdes->chunk.ssrc));
if(fixssrc && newssrcl) {
sdes->chunk.ssrc = htonl(newssrcl);
}
break;
}
case RTCP_BYE: {
/* BYE, goodbye */
JANUS_LOG(LOG_HUGE, " #%d BYE (203)\n", pno);
janus_rtcp_bye *bye = (janus_rtcp_bye *)rtcp;
//~ JANUS_LOG(LOG_HUGE, " -- SSRC: %u\n", ntohl(bye->ssrc[0]));
if(fixssrc && newssrcl) {
bye->ssrc[0] = htonl(newssrcl);
}
break;
}
case RTCP_APP: {
/* APP, application-defined */
JANUS_LOG(LOG_HUGE, " #%d APP (204)\n", pno);
janus_rtcp_app *app = (janus_rtcp_app *)rtcp;
//~ JANUS_LOG(LOG_HUGE, " -- SSRC: %u\n", ntohl(app->ssrc));
if(fixssrc && newssrcl) {
app->ssrc = htonl(newssrcl);
}
break;
}
case RTCP_FIR: {
/* FIR, rfc2032 */
JANUS_LOG(LOG_HUGE, " #%d FIR (192)\n", pno);
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
if(fixssrc && newssrcr && (ntohs(rtcp->length) >= 20)) {
rtcpfb->media = htonl(newssrcr);
}
if(fixssrc && newssrcr) {
uint32_t *ssrc = (uint32_t *)rtcpfb->fci;
*ssrc = htonl(newssrcr);
}
break;
}
case RTCP_RTPFB: {
/* RTPFB, Transport layer FB message (rfc4585) */
//~ JANUS_LOG(LOG_HUGE, " #%d RTPFB (205)\n", pno);
gint fmt = rtcp->rc;
//~ JANUS_LOG(LOG_HUGE, " -- FMT: %u\n", fmt);
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
//~ JANUS_LOG(LOG_HUGE, " -- SSRC: %u\n", ntohl(rtcpfb->ssrc));
if(fmt == 1) {
JANUS_LOG(LOG_HUGE, " #%d NACK -- RTPFB (205)\n", pno);
if(fixssrc && newssrcr) {
rtcpfb->media = htonl(newssrcr);
}
int nacks = ntohs(rtcp->length)-2; /* Skip SSRCs */
if(nacks > 0) {
JANUS_LOG(LOG_DBG, " Got %d nacks\n", nacks);
janus_rtcp_nack *nack = NULL;
uint16_t pid = 0;
uint16_t blp = 0;
int i=0, j=0;
char bitmask[20];
for(i=0; i< nacks; i++) {
nack = (janus_rtcp_nack *)rtcpfb->fci + i;
pid = ntohs(nack->pid);
blp = ntohs(nack->blp);
memset(bitmask, 0, 20);
for(j=0; j<16; j++) {
bitmask[j] = (blp & ( 1 << j )) >> j ? '1' : '0';
}
bitmask[16] = '\n';
JANUS_LOG(LOG_DBG, "[%d] %"SCNu16" / %s\n", i, pid, bitmask);
}
}
} else if(fmt == 3) { /* rfc5104 */
/* TMMBR: http://tools.ietf.org/html/rfc5104#section-4.2.1.1 */
JANUS_LOG(LOG_HUGE, " #%d TMMBR -- RTPFB (205)\n", pno);
if(fixssrc && newssrcr) {
uint32_t *ssrc = (uint32_t *)rtcpfb->fci;
*ssrc = htonl(newssrcr);
}
} else {
JANUS_LOG(LOG_HUGE, " #%d ??? -- RTPFB (205, fmt=%d)\n", pno, fmt);
}
if(fixssrc && newssrcl) {
rtcpfb->ssrc = htonl(newssrcl);
}
break;
}
case RTCP_PSFB: {
/* PSFB, Payload-specific FB message (rfc4585) */
//~ JANUS_LOG(LOG_HUGE, " #%d PSFB (206)\n", pno);
gint fmt = rtcp->rc;
//~ JANUS_LOG(LOG_HUGE, " -- FMT: %u\n", fmt);
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
//~ JANUS_LOG(LOG_HUGE, " -- SSRC: %u\n", ntohl(rtcpfb->ssrc));
if(fmt == 1) {
JANUS_LOG(LOG_HUGE, " #%d PLI -- PSFB (206)\n", pno);
if(fixssrc && newssrcr) {
rtcpfb->media = htonl(newssrcr);
}
} else if(fmt == 2) {
JANUS_LOG(LOG_HUGE, " #%d SLI -- PSFB (206)\n", pno);
} else if(fmt == 3) {
JANUS_LOG(LOG_HUGE, " #%d RPSI -- PSFB (206)\n", pno);
} else if(fmt == 4) { /* rfc5104 */
/* FIR: http://tools.ietf.org/html/rfc5104#section-4.3.1.1 */
JANUS_LOG(LOG_HUGE, " #%d FIR -- PSFB (206)\n", pno);
if(fixssrc && newssrcr) {
rtcpfb->media = htonl(newssrcr);
}
if(fixssrc && newssrcr) {
uint32_t *ssrc = (uint32_t *)rtcpfb->fci;
*ssrc = htonl(newssrcr);
}
} else if(fmt == 5) { /* rfc5104 */
/* FIR: http://tools.ietf.org/html/rfc5104#section-4.3.2.1 */
JANUS_LOG(LOG_HUGE, " #%d PLI -- TSTR (206)\n", pno);
if(fixssrc && newssrcr) {
uint32_t *ssrc = (uint32_t *)rtcpfb->fci;
*ssrc = htonl(newssrcr);
}
} else if(fmt == 15) {
//~ JANUS_LOG(LOG_HUGE, " -- This is a AFB!\n");
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
if(fixssrc && newssrcr) {
rtcpfb->ssrc = htonl(newssrcr);
rtcpfb->media = 0;
}
janus_rtcp_fb_remb *remb = (janus_rtcp_fb_remb *)rtcpfb->fci;
if(remb->id[0] == 'R' && remb->id[1] == 'E' && remb->id[2] == 'M' && remb->id[3] == 'B') {
JANUS_LOG(LOG_HUGE, " #%d REMB -- PSFB (206)\n", pno);
if(fixssrc && newssrcr) {
remb->ssrc[0] = htonl(newssrcr);
}
/* FIXME From rtcp_utility.cc */
unsigned char *_ptrRTCPData = (unsigned char *)remb;
_ptrRTCPData += 4; // Skip unique identifier and num ssrc
//~ JANUS_LOG(LOG_HUGE, " %02X %02X %02X %02X\n", _ptrRTCPData[0], _ptrRTCPData[1], _ptrRTCPData[2], _ptrRTCPData[3]);
uint8_t numssrc = (_ptrRTCPData[0]);
uint8_t brExp = (_ptrRTCPData[1] >> 2) & 0x3F;
uint32_t brMantissa = (_ptrRTCPData[1] & 0x03) << 16;
brMantissa += (_ptrRTCPData[2] << 8);
brMantissa += (_ptrRTCPData[3]);
uint32_t bitRate = brMantissa << brExp;
JANUS_LOG(LOG_HUGE, " -- -- -- REMB: %u * 2^%u = %"SCNu32" (%d SSRCs, %u)\n",
brMantissa, brExp, bitRate, numssrc, ntohl(remb->ssrc[0]));
} else {
JANUS_LOG(LOG_HUGE, " #%d AFB ?? -- PSFB (206)\n", pno);
}
} else {
JANUS_LOG(LOG_HUGE, " #%d ?? -- PSFB (206, fmt=%d)\n", pno, fmt);
}
if(fixssrc && newssrcl) {
rtcpfb->ssrc = htonl(newssrcl);
}
break;
}
case RTCP_XR: {
/* XR, extended reports (rfc3611) */
janus_rtcp_xr *xr = (janus_rtcp_xr *)rtcp;
if(fixssrc && newssrcl) {
xr->ssrc = htonl(newssrcl);
}
/* TODO Fix report blocks too, once we support them */
break;
}
default:
JANUS_LOG(LOG_ERR, " Unknown RTCP PT %d\n", rtcp->type);
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
JANUS_LOG(LOG_HUGE, " RTCP PT %d, length: %d bytes\n", rtcp->type, length*4+4);
if(length == 0) {
//~ JANUS_LOG(LOG_HUGE, " 0-length, end of compound packet\n");
break;
}
total -= length*4+4;
//~ JANUS_LOG(LOG_HUGE, " Packet has length %d (%d bytes, %d remaining), moving to next one...\n", length, length*4+4, total);
if(total <= 0) {
JANUS_LOG(LOG_HUGE, " End of compound packet\n");
break;
}
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return 0;
}
char *janus_rtcp_filter(char *packet, int len, int *newlen) {
if(packet == NULL || len <= 0 || newlen == NULL)
return NULL;
*newlen = 0;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return NULL;
char *filtered = NULL;
int total = len, length = 0, bytes = 0;
/* Iterate on the compound packets */
gboolean keep = TRUE;
while(rtcp) {
keep = TRUE;
length = ntohs(rtcp->length);
if(length == 0)
break;
bytes = length*4+4;
switch(rtcp->type) {
case RTCP_SR:
case RTCP_RR:
case RTCP_SDES:
/* These are packets we generate ourselves, so remove them */
keep = FALSE;
break;
case RTCP_BYE:
case RTCP_APP:
case RTCP_FIR:
case RTCP_PSFB:
break;
case RTCP_RTPFB:
if(rtcp->rc == 1) {
/* We handle NACKs ourselves as well, remove this too */
keep = FALSE;
break;
}
break;
case RTCP_XR:
/* FIXME We generate RR/SR ourselves, so remove XR */
keep = FALSE;
break;
default:
JANUS_LOG(LOG_ERR, "Unknown RTCP PT %d\n", rtcp->type);
/* FIXME Should we allow this to go through instead? */
keep = FALSE;
break;
}
if(keep) {
/* Keep this packet */
if(filtered == NULL)
filtered = g_malloc0(total);
memcpy(filtered+*newlen, (char *)rtcp, bytes);
*newlen += bytes;
}
total -= bytes;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return filtered;
}
int janus_rtcp_process_incoming_rtp(janus_rtcp_context *ctx, char *packet, int len) {
if(ctx == NULL || packet == NULL || len < 1)
return -1;
/* First of all, let's check if this is G.711: in case we may need to change the timestamp base */
janus_rtp_header *rtp = (janus_rtp_header *)packet;
int pt = rtp->type;
if((pt == 0 || pt == 8) && (ctx->tb == 48000))
ctx->tb = 8000;
/* Now parse this RTP packet header and update the rtcp_context instance */
uint16_t seq_number = ntohs(rtp->seq_number);
if(ctx->base_seq == 0 && ctx->seq_cycle == 0)
ctx->base_seq = seq_number;
if(seq_number < ctx->last_seq_nr) {
if(ctx->last_seq_nr - seq_number < 1000) {
/* FIXME Just a retransmission, not a reset, ignore */
return 0;
}
ctx->seq_cycle++;
}
ctx->last_seq_nr = seq_number;
ctx->received++;
uint32_t rtp_expected = 0x0;
if(ctx->seq_cycle > 0) {
rtp_expected = ctx->seq_cycle;
rtp_expected = rtp_expected << 16;
}
rtp_expected = rtp_expected + 1 + seq_number - ctx->base_seq;
ctx->lost = rtp_expected - ctx->received;
ctx->expected = rtp_expected;
uint64_t arrival = (janus_get_monotonic_time() * ctx->tb) / 1000000;
uint64_t transit = arrival - ntohl(rtp->timestamp);
uint64_t d = abs(transit - ctx->transit);
ctx->transit = transit;
ctx->jitter += (1./16.) * ((double)d - ctx->jitter);
/* RTP packet received: it means we can start sending RR */
ctx->rtp_recvd = 1;
return 0;
}
uint32_t janus_rtcp_context_get_rtt(janus_rtcp_context *ctx) {
return ctx ? ctx->rtt : 0;
}
uint32_t janus_rtcp_context_get_lost_all(janus_rtcp_context *ctx, gboolean remote) {
if(ctx == NULL)
return 0;
return remote ? ctx->lost_remote : ctx->lost;
}
static uint32_t janus_rtcp_context_get_lost(janus_rtcp_context *ctx) {
if(ctx == NULL)
return 0;
uint32_t lost;
if(ctx->lost > 0x7FFFFF) {
lost = 0x7FFFFF;
} else {
lost = ctx->lost;
}
return lost;
}
static uint32_t janus_rtcp_context_get_lost_fraction(janus_rtcp_context *ctx) {
if(ctx == NULL)
return 0;
uint32_t expected_interval = ctx->expected - ctx->expected_prior;
uint32_t received_interval = ctx->received - ctx->received_prior;
int32_t lost_interval = expected_interval - received_interval;
uint32_t fraction;
if(expected_interval == 0 || lost_interval <=0)
fraction = 0;
else
fraction = (lost_interval << 8) / expected_interval;
return fraction << 24;
}
uint32_t janus_rtcp_context_get_jitter(janus_rtcp_context *ctx, gboolean remote) {
if(ctx == NULL || ctx->tb == 0)
return 0;
return (uint32_t) floor((remote ? ctx->jitter_remote : ctx->jitter) * 1000.0 / ctx->tb);
}
int janus_rtcp_report_block(janus_rtcp_context *ctx, janus_report_block *rb) {
if(ctx == NULL || rb == NULL)
return -1;
gint64 now = janus_get_monotonic_time();
rb->jitter = htonl((uint32_t) ctx->jitter);
rb->ehsnr = htonl((((uint32_t) 0x0 + ctx->seq_cycle) << 16) + ctx->last_seq_nr);
uint32_t lost = janus_rtcp_context_get_lost(ctx);
uint32_t fraction = janus_rtcp_context_get_lost_fraction(ctx);
ctx->expected_prior = ctx->expected;
ctx->received_prior = ctx->received;
rb->flcnpl = htonl(lost | fraction);
if(ctx->lsr > 0) {
rb->lsr = htonl(ctx->lsr);
rb->delay = htonl(((now - ctx->lsr_ts) << 16) / 1000000);
} else {
rb->lsr = 0;
rb->delay = 0;
}
ctx->last_sent = now;
return 0;
}
int janus_rtcp_has_bye(char *packet, int len) {
gboolean got_bye = FALSE;
/* Parse RTCP compound packet */
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return FALSE;
int pno = 0, total = len;
while(rtcp) {
pno++;
switch(rtcp->type) {
case RTCP_BYE:
got_bye = TRUE;
break;
default:
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return got_bye ? TRUE : FALSE;
}
int janus_rtcp_has_fir(char *packet, int len) {
gboolean got_fir = FALSE;
/* Parse RTCP compound packet */
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return FALSE;
int pno = 0, total = len;
while(rtcp) {
pno++;
switch(rtcp->type) {
case RTCP_FIR:
got_fir = TRUE;
break;
default:
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return got_fir ? TRUE : FALSE;
}
int janus_rtcp_has_pli(char *packet, int len) {
gboolean got_pli = FALSE;
/* Parse RTCP compound packet */
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return FALSE;
int pno = 0, total = len;
while(rtcp) {
pno++;
switch(rtcp->type) {
case RTCP_PSFB: {
gint fmt = rtcp->rc;
if(fmt == 1)
got_pli = TRUE;
break;
}
default:
break;
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return got_pli ? TRUE : FALSE;
}
GSList *janus_rtcp_get_nacks(char *packet, int len) {
if(packet == NULL || len == 0)
return NULL;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return NULL;
/* FIXME Get list of sequence numbers we should send again */
GSList *list = NULL;
int total = len;
while(rtcp) {
if(rtcp->type == RTCP_RTPFB) {
gint fmt = rtcp->rc;
if(fmt == 1) {
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
int nacks = ntohs(rtcp->length)-2; /* Skip SSRCs */
if(nacks > 0) {
JANUS_LOG(LOG_DBG, " Got %d nacks\n", nacks);
janus_rtcp_nack *nack = NULL;
uint16_t pid = 0;
uint16_t blp = 0;
int i=0, j=0;
char bitmask[20];
for(i=0; i< nacks; i++) {
nack = (janus_rtcp_nack *)rtcpfb->fci + i;
pid = ntohs(nack->pid);
list = g_slist_append(list, GUINT_TO_POINTER(pid));
blp = ntohs(nack->blp);
memset(bitmask, 0, 20);
for(j=0; j<16; j++) {
bitmask[j] = (blp & ( 1 << j )) >> j ? '1' : '0';
if((blp & ( 1 << j )) >> j)
list = g_slist_append(list, GUINT_TO_POINTER(pid+j+1));
}
bitmask[16] = '\n';
JANUS_LOG(LOG_DBG, "[%d] %"SCNu16" / %s\n", i, pid, bitmask);
}
}
}
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return list;
}
int janus_rtcp_remove_nacks(char *packet, int len) {
if(packet == NULL || len == 0)
return len;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return len;
/* Find the NACK message */
char *nacks = NULL;
int total = len, nacks_len = 0;
while(rtcp) {
if(rtcp->type == RTCP_RTPFB) {
gint fmt = rtcp->rc;
if(fmt == 1) {
nacks = (char *)rtcp;
}
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
if(nacks != NULL) {
nacks_len = length*4+4;
break;
}
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
if(nacks != NULL) {
total = len - ((nacks-packet)+nacks_len);
if(total < 0) {
/* FIXME Should never happen, but you never know: do nothing */
return len;
} else if(total == 0) {
/* NACK was the last compound packet, easy enough */
return len-nacks_len;
} else {
/* NACK is between two compound packets, move them around */
int i=0;
for(i=0; i<total; i++)
*(nacks+i) = *(nacks+nacks_len+i);
return len-nacks_len;
}
}
return len;
}
/* Query an existing REMB message */
uint32_t janus_rtcp_get_remb(char *packet, int len) {
if(packet == NULL || len == 0)
return 0;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return 0;
/* Get REMB bitrate, if any */
int total = len;
while(rtcp) {
if(rtcp->type == RTCP_PSFB) {
gint fmt = rtcp->rc;
if(fmt == 15) {
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
janus_rtcp_fb_remb *remb = (janus_rtcp_fb_remb *)rtcpfb->fci;
if(remb->id[0] == 'R' && remb->id[1] == 'E' && remb->id[2] == 'M' && remb->id[3] == 'B') {
/* FIXME From rtcp_utility.cc */
unsigned char *_ptrRTCPData = (unsigned char *)remb;
_ptrRTCPData += 4; /* Skip unique identifier and num ssrc */
//~ JANUS_LOG(LOG_VERB, " %02X %02X %02X %02X\n", _ptrRTCPData[0], _ptrRTCPData[1], _ptrRTCPData[2], _ptrRTCPData[3]);
uint8_t brExp = (_ptrRTCPData[1] >> 2) & 0x3F;
uint32_t brMantissa = (_ptrRTCPData[1] & 0x03) << 16;
brMantissa += (_ptrRTCPData[2] << 8);
brMantissa += (_ptrRTCPData[3]);
uint32_t bitrate = brMantissa << brExp;
JANUS_LOG(LOG_HUGE, "Got REMB bitrate %"SCNu32"\n", bitrate);
return bitrate;
}
}
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return 0;
}
/* Change an existing REMB message */
int janus_rtcp_cap_remb(char *packet, int len, uint32_t bitrate) {
if(packet == NULL || len == 0)
return -1;
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
if(rtcp->version != 2)
return -2;
if(bitrate == 0)
return 0; /* No need to cap */
/* Cap REMB bitrate */
int total = len;
while(rtcp) {
if(rtcp->type == RTCP_PSFB) {
gint fmt = rtcp->rc;
if(fmt == 15) {
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
janus_rtcp_fb_remb *remb = (janus_rtcp_fb_remb *)rtcpfb->fci;
if(remb->id[0] == 'R' && remb->id[1] == 'E' && remb->id[2] == 'M' && remb->id[3] == 'B') {
/* FIXME From rtcp_utility.cc */
unsigned char *_ptrRTCPData = (unsigned char *)remb;
_ptrRTCPData += 4; /* Skip unique identifier and num ssrc */
//~ JANUS_LOG(LOG_VERB, " %02X %02X %02X %02X\n", _ptrRTCPData[0], _ptrRTCPData[1], _ptrRTCPData[2], _ptrRTCPData[3]);
uint8_t brExp = (_ptrRTCPData[1] >> 2) & 0x3F;
uint32_t brMantissa = (_ptrRTCPData[1] & 0x03) << 16;
brMantissa += (_ptrRTCPData[2] << 8);
brMantissa += (_ptrRTCPData[3]);
uint32_t origbitrate = brMantissa << brExp;
if(origbitrate > bitrate) {
JANUS_LOG(LOG_HUGE, "Got REMB bitrate %"SCNu32", need to cap it to %"SCNu32"\n", origbitrate, bitrate);
JANUS_LOG(LOG_HUGE, " >> %u * 2^%u = %"SCNu32"\n", brMantissa, brExp, origbitrate);
/* bitrate --> brexp/brmantissa */
uint8_t b = 0;
uint8_t newbrexp = 0;
uint32_t newbrmantissa = 0;
for(b=0; b<32; b++) {
if(bitrate <= ((uint32_t) 0x3FFFF << b)) {
newbrexp = b;
break;
}
}
if(b > 31)
b = 31;
newbrmantissa = bitrate >> b;
JANUS_LOG(LOG_HUGE, "new brexp: %"SCNu8"\n", newbrexp);
JANUS_LOG(LOG_HUGE, "new brmantissa: %"SCNu32"\n", newbrmantissa);
/* FIXME From rtcp_sender.cc */
_ptrRTCPData[1] = (uint8_t)((newbrexp << 2) + ((newbrmantissa >> 16) & 0x03));
_ptrRTCPData[2] = (uint8_t)(newbrmantissa >> 8);
_ptrRTCPData[3] = (uint8_t)(newbrmantissa);
}
}
}
}
/* Is this a compound packet? */
int length = ntohs(rtcp->length);
if(length == 0)
break;
total -= length*4+4;
if(total <= 0)
break;
rtcp = (janus_rtcp_header *)((uint32_t*)rtcp + length + 1);
}
return 0;
}
/* Generate a new SDES message */
int janus_rtcp_sdes_cname(char *packet, int len, const char *cname, int cnamelen) {
if(packet == NULL || len <= 0 || cname == NULL || cnamelen <= 0)
return -1;
memset(packet, 0, len);
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
/* Set header */
rtcp->version = 2;
rtcp->type = RTCP_SDES;
rtcp->rc = 1;
int plen = 8; /* Header + chunk + item header */
plen += cnamelen+2;
if((cnamelen+2)%4) /* Account for padding */
plen += 4;
if(len < plen) {
JANUS_LOG(LOG_ERR, "Buffer too small for SDES message: %d < %d\n", len, plen);
return -1;
}
rtcp->length = htons((plen/4)-1);
/* Now set SDES stuff */
janus_rtcp_sdes *rtcpsdes = (janus_rtcp_sdes *)rtcp;
rtcpsdes->item.type = 1;
rtcpsdes->item.len = cnamelen;
memcpy(rtcpsdes->item.content, cname, cnamelen);
return plen;
}
/* Generate a new REMB message */
int janus_rtcp_remb(char *packet, int len, uint32_t bitrate) {
/* By default we assume a single SSRC will be set */
return janus_rtcp_remb_ssrcs(packet, len, bitrate, 1);
}
int janus_rtcp_remb_ssrcs(char *packet, int len, uint32_t bitrate, uint8_t numssrc) {
if(packet == NULL || numssrc == 0)
return -1;
int min_len = 20 + numssrc*4;
if(len < min_len)
return -1;
memset(packet, 0, len);
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
/* Set header */
rtcp->version = 2;
rtcp->type = RTCP_PSFB;
rtcp->rc = 15;
rtcp->length = htons((min_len/4)-1);
/* Now set REMB stuff */
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
janus_rtcp_fb_remb *remb = (janus_rtcp_fb_remb *)rtcpfb->fci;
remb->id[0] = 'R';
remb->id[1] = 'E';
remb->id[2] = 'M';
remb->id[3] = 'B';
/* bitrate --> brexp/brmantissa */
uint8_t b = 0;
uint8_t newbrexp = 0;
uint32_t newbrmantissa = 0;
for(b=0; b<32; b++) {
if(bitrate <= ((uint32_t) 0x3FFFF << b)) {
newbrexp = b;
break;
}
}
if(b > 31)
b = 31;
newbrmantissa = bitrate >> b;
/* FIXME From rtcp_sender.cc */
unsigned char *_ptrRTCPData = (unsigned char *)remb;
_ptrRTCPData += 4; /* Skip unique identifier */
_ptrRTCPData[0] = numssrc;
_ptrRTCPData[1] = (uint8_t)((newbrexp << 2) + ((newbrmantissa >> 16) & 0x03));
_ptrRTCPData[2] = (uint8_t)(newbrmantissa >> 8);
_ptrRTCPData[3] = (uint8_t)(newbrmantissa);
JANUS_LOG(LOG_HUGE, "[REMB] bitrate=%"SCNu32" (%d bytes)\n", bitrate, 4*(ntohs(rtcp->length)+1));
return min_len;
}
/* Generate a new FIR message */
int janus_rtcp_fir(char *packet, int len, int *seqnr) {
if(packet == NULL || len != 20 || seqnr == NULL)
return -1;
memset(packet, 0, len);
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
*seqnr = *seqnr + 1;
if(*seqnr < 0 || *seqnr >= 256)
*seqnr = 0; /* Reset sequence number */
/* Set header */
rtcp->version = 2;
rtcp->type = RTCP_PSFB;
rtcp->rc = 4; /* FMT=4 */
rtcp->length = htons((len/4)-1);
/* Now set FIR stuff */
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
janus_rtcp_fb_fir *fir = (janus_rtcp_fb_fir *)rtcpfb->fci;
fir->seqnr = htonl(*seqnr << 24); /* FCI: Sequence number */
JANUS_LOG(LOG_HUGE, "[FIR] seqnr=%d (%d bytes)\n", *seqnr, 4*(ntohs(rtcp->length)+1));
return 20;
}
/* Generate a new legacy FIR message */
int janus_rtcp_fir_legacy(char *packet, int len, int *seqnr) {
/* FIXME Right now, this is identical to the new FIR, with the difference that we use 192 as PT */
if(packet == NULL || len != 20 || seqnr == NULL)
return -1;
memset(packet, 0, len);
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
*seqnr = *seqnr + 1;
if(*seqnr < 0 || *seqnr >= 256)
*seqnr = 0; /* Reset sequence number */
/* Set header */
rtcp->version = 2;
rtcp->type = RTCP_FIR;
rtcp->rc = 4; /* FMT=4 */
rtcp->length = htons((len/4)-1);
/* Now set FIR stuff */
janus_rtcp_fb *rtcpfb = (janus_rtcp_fb *)rtcp;
janus_rtcp_fb_fir *fir = (janus_rtcp_fb_fir *)rtcpfb->fci;
fir->seqnr = htonl(*seqnr << 24); /* FCI: Sequence number */
JANUS_LOG(LOG_HUGE, "[FIR] seqnr=%d (%d bytes)\n", *seqnr, 4*(ntohs(rtcp->length)+1));
return 20;
}
/* Generate a new PLI message */
int janus_rtcp_pli(char *packet, int len) {
if(packet == NULL || len != 12)
return -1;
memset(packet, 0, len);
janus_rtcp_header *rtcp = (janus_rtcp_header *)packet;
/* Set header */
rtcp->version = 2;
rtcp->type = RTCP_PSFB;
rtcp->rc = 1; /* FMT=1 */
rtcp->length = htons((len/4)-1);
return 12;