bool
MembershipBookkeeping::removeSource(uint32 ssrc)
{
bool found = false;
SyncSourceLink* old = NULL,
* s = sourceLinks[ HASH(ssrc) ];
while ( s != NULL ){
if ( s->getSource()->getID() == ssrc ) {
// we found it
if ( old )
old->setNextCollis(s->getNextCollis());
if ( s->getPrev() )
s->getPrev()->setNext(s->getNext());
if ( s->getNext() )
s->getNext()->setPrev(s->getPrev());
decreaseMembersCount();
if ( s->getSource()->isSender() )
decreaseSendersCount();
delete s;
found = true;
break;
} else if ( s->getSource()->getID() > ssrc ) {
// it wasn't here
break;
} else {
// keep on searching
old = s;
s = s->getNextCollis();
}
}
return found;
}
// Gets or creates the source and its link structure.
MembershipBookkeeping::SyncSourceLink*
MembershipBookkeeping::getSourceBySSRC(uint32 ssrc, bool& created)
{
uint32 hashing = HASH(ssrc);
SyncSourceLink* result = sourceLinks[hashing];
SyncSourceLink* prev = NULL;
created = false;
if ( NULL == result ) {
result = sourceLinks[hashing] =
new SyncSourceLink(this,new SyncSource(ssrc));
created = true;
} else {
while ( NULL != result ) {
if ( ssrc == result->getSource()->getID() ) {
// we found it!
break;
} else if ( ssrc > result->getSource()->getID() ) {
// keep on searching
prev = result;
result = result->getNextCollis();
} else {
// ( ssrc < result->getSource()->getID() )
// it isn't recorded here -> create it.
SyncSourceLink* newlink =
new SyncSourceLink(this,new SyncSource(ssrc));
if ( NULL != prev )
prev->setNextCollis(newlink);
else
sourceLinks[hashing] = newlink;
newlink->setNextCollis(result);
result = newlink;
created = true;
break;
}
}
if ( NULL == result ) {
// insert at the end of the collision list
result =
new SyncSourceLink(this,new SyncSource(ssrc));
created = true;
prev->setNextCollis(result);
}
}
if ( created ) {
if ( first )
last->setNext(result);
else
first = result;
last = result;
increaseMembersCount();
}
return result;
}
bool
MembershipBookkeeping::isRegistered(uint32 ssrc)
{
bool result = false;
SyncSourceLink* sl = sourceLinks[ HASH(ssrc) ];
while ( sl != NULL ) {
if ( ssrc == sl->getSource()->getID() ) {
result = true;
break;
} else if ( ssrc < sl->getSource()->getID() ) {
break;
} else {
// keep on searching
sl = sl->getNextCollis();
}
}
return result;
}
size_t
ZrtpQueue::rtpDataPacket(unsigned char* buffer, int32 rtn, InetHostAddress network_address, tpport_t transport_port)
{
// Special handling of padding to take care of encrypted content.
// In case of SRTP the padding length field is also encrypted, thus
// it gives a wrong length. Check and clear padding bit before
// creating the RTPPacket. Will be set and re-computed after a possible
// SRTP decryption.
uint8 padSet = (*buffer & 0x20);
if (padSet) {
*buffer = *buffer & ~0x20; // clear padding bit
}
// build a packet. It will link itself to its source
IncomingRTPPkt* packet =
new IncomingRTPPkt(buffer,rtn);
// Generic header validity check.
if ( !packet->isHeaderValid() ) {
delete packet;
return 0;
}
// Look for a CryptoContext for this packet's SSRC
CryptoContext* pcc = getInQueueCryptoContext(packet->getSSRC());
// If no crypto context is available for this SSRC but we are already in
// Secure state then create a CryptoContext for this SSRC.
// Assumption: every SSRC stream sent via this connection is secured
// _and_ uses the same crypto parameters.
if (pcc == NULL) {
pcc = getInQueueCryptoContext(0);
if (pcc != NULL) {
pcc = pcc->newCryptoContextForSSRC(packet->getSSRC(), 0, 0L);
if (pcc != NULL) {
pcc->deriveSrtpKeys(0);
setInQueueCryptoContext(pcc);
}
}
}
// If no crypto context: then either ZRTP is off or in early state
// If crypto context is available then unprotect data here. If an error
// occurs report the error and discard the packet.
if (pcc != NULL) {
int32 ret;
if ((ret = packet->unprotect(pcc)) < 0) {
if (!onSRTPPacketError(*packet, ret)) {
delete packet;
return 0;
}
}
if (started && zrtpEngine->inState(WaitConfAck)) {
zrtpEngine->conf2AckSecure();
}
}
// virtual for profile-specific validation and processing.
if (!onRTPPacketRecv(*packet) ) {
delete packet;
return 0;
}
if (padSet) {
packet->reComputePayLength(true);
}
// get time of arrival
struct timeval recvtime;
gettimeofday(&recvtime,NULL);
bool source_created;
SyncSourceLink* sourceLink =
getSourceBySSRC(packet->getSSRC(),source_created);
SyncSource* s = sourceLink->getSource();
if ( source_created ) {
// Set data transport address.
setDataTransportPort(*s,transport_port);
// Network address is assumed to be the same as the control one
setNetworkAddress(*s,network_address);
sourceLink->initStats();
// First packet arrival time.
sourceLink->setInitialDataTime(recvtime);
sourceLink->setProbation(getMinValidPacketSequence());
if ( sourceLink->getHello() )
onNewSyncSource(*s);
}
else if ( 0 == s->getDataTransportPort() ) {
// Test if RTCP packets had been received but this is the
// first data packet from this source.
setDataTransportPort(*s,transport_port);
}
// Before inserting in the queue,
// 1) check for collisions and loops. If the packet cannot be
// assigned to a source, it will be rejected.
// 2) check the source is a sufficiently well known source
// TODO: also check CSRC identifiers.
if (checkSSRCInIncomingRTPPkt(*sourceLink, source_created,
network_address, transport_port) &&
recordReception(*sourceLink,*packet,recvtime) ) {
// now the packet link is linked in the queues
IncomingRTPPktLink* packetLink = new IncomingRTPPktLink(packet, sourceLink, recvtime,
packet->getTimestamp() - sourceLink->getInitialDataTimestamp(),
NULL,NULL,NULL,NULL);
insertRecvPacket(packetLink);
} else {
// must be discarded due to collision or loop or
// invalid source
delete packet;
return 0;
}
// Start the ZRTP engine after we got a at least one RTP packet and
// sent some as well or we are in multi-stream mode.
if (!started && enableZrtp) {
startZrtp();
}
return rtn;
}
