boolean RF22ReliableDatagram::sendtoWait(uint8_t* buf, uint8_t len, uint8_t address)
{
// Assemble the message
uint8_t thisSequenceNumber = ++_lastSequenceNumber;
Timer t;
uint8_t retries = 0;
while (retries++ <= _retries)
{
setHeaderId(thisSequenceNumber);
setHeaderFlags(0);
sendto(buf, len, address);
waitPacketSent(3000);
// Never wait for ACKS to broadcasts:
if (address == RF22_BROADCAST_ADDRESS)
return true;
if (retries > 1)
_retransmissions++;
t.start();
unsigned long thisSendTime = t.read_ms(); // Timeout does not include original transmit time
// Compute a new timeout, random between _timeout and _timeout*2
// This is to prevent collisions on every retransmit
// if 2 nodes try to transmit at the same time
uint16_t timeout = _timeout + (_timeout * (rand() % 100) / 100);
while (t.read_ms() < (thisSendTime + timeout))
{
if (available()) {
clearRxBuf(); // Not using recv, so clear it ourselves
uint8_t from = headerFrom();
uint8_t to = headerTo();
uint8_t id = headerId();
uint8_t flags = headerFlags();
// Now have a message: is it our ACK?
if ( from == address
&& to == _thisAddress
&& (flags & RF22_FLAGS_ACK)
&& (id == thisSequenceNumber))
{
// Its the ACK we are waiting for
return true;
}
else if ( !(flags & RF22_FLAGS_ACK)
&& (id == _seenIds[from]))
{
// This is a request we have already received. ACK it again
acknowledge(id, from);
}
// Else discard it
}
// Not the one we are waiting for, maybe keep waiting until timeout exhausted
}
// Timeout exhausted, maybe retry
}
return false;
}
boolean RF22Datagram::recvfrom(uint8_t* buf, uint8_t* len, uint8_t* from, uint8_t* to, uint8_t* id, uint8_t* flags)
{
if (from) *from = headerFrom();
if (to) *to = headerTo();
if (id) *id = headerId();
if (flags) *flags = headerFlags();
return recv(buf, len);
}
bool RHDatagram::recvfrom(uint8_t* buf, uint8_t* len, uint8_t* from, uint8_t* to, uint8_t* id, uint8_t* flags)
{
if (_driver.recv(buf, len))
{
if (from) *from = headerFrom();
if (to) *to = headerTo();
if (id) *id = headerId();
if (flags) *flags = headerFlags();
return true;
}
return false;
}
