int DatagramSocket::read(DatagramPacket &pkt)
{
int numbytes;
sockaddr_in addr;
socklen_t addr_len=sizeof(addr);
if ((numbytes=recvfrom(*((socket_t*)m_sock), (char *)pkt.getBuffer().getData(), pkt.getBuffer().getLength(), 0,
(sockaddr *)&addr, &addr_len)) == -1)
{
Error_send("Unable to receive packet from UDP socket\n");
}
pkt.setPort(addr.sin_port);
pkt.setAddress(InetAddress(inet_ntoa(addr.sin_addr)));
pkt.setLength(numbytes);
return numbytes;
}
//==============================================================================
// PlainDatagramSocketImpl::receive
//
//==============================================================================
void PlainDatagramSocketImpl::receive(DatagramPacket& p)
{
testSocketIsValid();
sockaddr_in remoteAddr;
cel_socklen_t addrLen;
sockaddr* pRemoteAddr = reinterpret_cast<struct sockaddr*>(&remoteAddr);
int recvLength;
//
// The following code is placed within a while() block to attempt to unify
// the behaviour on multiple platforms. If this datagram socket has been
// used to send a dataram packet, an ICMP response may be received to
// indicate that the send request was unsuccessful. This behaviour is not
// always helpful and is not guaranteed to occur (but seems to on Windows).
// There is a far greater liklihood of this behaviour occurring on all platforms
// when the socket has been connected to a particular host. For this reason,
// connect errors are ignored unless the socket has been connected.
//
while(true)
{
// simulate SO_TIMEOUT
if(m_nTimeoutMS && !NetUtils::SelectSocket(m_rpSocketDescriptor.get(), m_nTimeoutMS,true,false))
{
static const String err(QC_T("receive timed out"));
throw SocketTimeoutException(err);
}
int flags = 0;
addrLen = sizeof(remoteAddr);
recvLength = recvfrom(m_rpSocketDescriptor->getFD(),
(char*) p.getData(),
p.getLength(),
flags,
pRemoteAddr,
&addrLen);
if(recvLength < 0)
{
const int errorNum = NetUtils::GetLastSocketError();
// Failure of recvfrom may be cause by the buffer length being smaller
// than the message (in which case we silently ignore it, and set the
// received length equal to the buffer length supplied), or due to
// some other serious problem which will result in a SocketException
//
if(errorNum == QC_EMSGSIZE)
{
recvLength = p.getLength();
break;
}
else if(!isConnected() && (errorNum == QC_ECONNRESET || errorNum == QC_ECONNABORTED || errorNum == QC_EHOSTUNREACH))
{
// See detailed comment above
continue;
}
else
{
static const String err(QC_T("error calling recvfrom "));
String errMsg = err + NetUtils::GetSocketErrorString(errorNum);
throw SocketException(errMsg);
}
}
else
{
break;
}
}
//
// Note: this test should migrate to the InetAddress class
//
if(addrLen != sizeof(sockaddr_in))
{
static const String err(QC_T("recvfrom() returned invalid address size"));
throw SocketException(err);
}
//
// Update the DatagramPacket with the address/length info
//
p.setPort(ntohs(remoteAddr.sin_port));
p.setAddress(InetAddress::FromNetworkAddress(pRemoteAddr, addrLen).get());
p.setLength(recvLength);
if(Tracer::IsEnabled())
{
Tracer::TraceBytes(Tracer::Net, Tracer::Low, QC_T("Datagram rcvd:"), p.getData(), recvLength);
}
}