/*********************************************************************
* Function: BOOL UDPProcess(NODE_INFO* remoteNode,
* WORD len)
*
* PreCondition: UDPInit() is already called AND
* UDP segment is ready in MAC buffer
*
* Input: remoteNode - Remote node info
* len - Total length of UDP semgent.
*
* Output: TRUE if this function has completed its task
* FALSE otherwise
*
* Side Effects: None
*
* Overview: None
*
* Note: None
********************************************************************/
BOOL UDPProcess(NODE_INFO *remoteNode, WORD len)
{
UDP_HEADER h;
UDP_SOCKET s;
/*
* Retrieve UDP header.
*/
MACGetArray((BYTE*)&h, sizeof(h));
h.SourcePort = swaps(h.SourcePort);
h.DestinationPort = swaps(h.DestinationPort);
h.Length = swaps(h.Length) - sizeof(UDP_HEADER);;
h.Checksum = swaps(h.Checksum);
s = FindMatchingSocket(&h, remoteNode);
if ( s == INVALID_UDP_SOCKET )
{
/*
* If there is no matching socket, There is no one to handle
* this data. Discard it.
*/
MACDiscardRx();
}
else
{
UDPSocketInfo[s].RxCount = h.Length;
UDPSocketInfo[s].Flags.bFirstRead = TRUE;
}
return TRUE;
}
/*****************************************************************************
Function:
BOOL UDPProcess(NODE_INFO *remoteNode, IP_ADDR *localIP, WORD len)
Summary:
Handles an incoming UDP segment.
Description:
This function handles an incoming UDP segment to determine if it is
acceptable and should be handed to one of the stack applications for
processing.
Precondition:
UDPInit() has been called an a UDP segment is ready in the MAC buffer.
Parameters:
remoteNode - The remote node that sent this segment.
localIP - The destination IP address for this segment.
len - Total length of the UDP segment.
Return Values:
TRUE - A valid packet is waiting and the stack applications should be
called to handle it.
FALSE - The packet was discarded.
***************************************************************************/
BOOL UDPProcess(NODE_INFO *remoteNode, IP_ADDR *localIP, WORD len)
{
UDP_HEADER h;
UDP_SOCKET s;
PSEUDO_HEADER pseudoHeader;
DWORD_VAL checksums;
UDPRxCount = 0;
// Retrieve UDP header.
MACGetArray((BYTE*)&h, sizeof(h));
h.SourcePort = swaps(h.SourcePort);
h.DestinationPort = swaps(h.DestinationPort);
h.Length = swaps(h.Length) - sizeof(UDP_HEADER);
// See if we need to validate the checksum field (0x0000 is disabled)
if(h.Checksum)
{
// Calculate IP pseudoheader checksum.
pseudoHeader.SourceAddress = remoteNode->IPAddr;
pseudoHeader.DestAddress.Val = localIP->Val;
pseudoHeader.Zero = 0x0;
pseudoHeader.Protocol = IP_PROT_UDP;
pseudoHeader.Length = len;
SwapPseudoHeader(pseudoHeader);
checksums.w[0] = ~CalcIPChecksum((BYTE*)&pseudoHeader,
sizeof(pseudoHeader));
// Now calculate UDP packet checksum in NIC RAM -- should match pseudoHeader
IPSetRxBuffer(0);
checksums.w[1] = CalcIPBufferChecksum(len);
if(checksums.w[0] != checksums.w[1])
{
MACDiscardRx();
return FALSE;
}
}
s = FindMatchingSocket(&h, remoteNode, localIP);
if(s == INVALID_UDP_SOCKET)
{
// If there is no matching socket, There is no one to handle
// this data. Discard it.
MACDiscardRx();
return FALSE;
}
else
{
SocketWithRxData = s;
UDPRxCount = h.Length;
Flags.bFirstRead = 1;
Flags.bWasDiscarded = 0;
}
return TRUE;
}
/**
* Performs UDP related tasks. Must continuesly be called.
*
* @preCondition UDPInit() is already called AND <br>
* UDP segment is ready in MAC buffer
*
* @param remoteNode Remote node info
* @param len Total length of UDP semgent
* @param destIP The Destination IP Address of the currently received packet
*
* @return TRUE if this function has completed its task <br>
* FALSE otherwise
*/
BOOL UDPProcess(NODE_INFO *remoteNode, IP_ADDR *destIP, WORD len)
{
UDP_HEADER h;
UDP_SOCKET s;
PSEUDO_HEADER pseudoHeader;
WORD_VAL checksum;
#if defined(UDP_SPEED_OPTIMIZE)
BYTE temp;
#endif
//Retrieve UDP header. The data is read from the current MAC RX Buffer
MACGetArray((BYTE*)&h, sizeof(h));
#if defined(UDP_SPEED_OPTIMIZE)
temp = h.SourcePort.v[0];
h.SourcePort.v[0] = h.SourcePort.v[1];
h.SourcePort.v[1] = temp;
temp = h.DestinationPort.v[0];
h.DestinationPort.v[0] = h.DestinationPort.v[1];
h.DestinationPort.v[1] = temp;
//Will an overflow occur after the subtraction?
if ((BYTE)sizeof(UDP_HEADER) > h.Length.v[1]) {
temp = h.Length.v[0] - 1;
}
else {
temp = h.Length.v[0];
}
h.Length.v[0] = h.Length.v[1] - (BYTE)sizeof(UDP_HEADER);
h.Length.v[1] = temp;
#else
h.SourcePort.Val = swaps(h.SourcePort.Val);
h.DestinationPort.Val = swaps(h.DestinationPort.Val);
h.Length.Val = swaps(h.Length.Val) - sizeof(UDP_HEADER);
#endif
// See if we need to validate the checksum field (0x0000 is disabled)
if(h.Checksum.Val)
{
#if defined(UDP_SPEED_OPTIMIZE)
temp = h.Checksum.v[0];
h.Checksum.v[0] = h.Checksum.v[1];
h.Checksum.v[1] = temp;
#else
h.Checksum.Val = swaps(h.Checksum.Val);
#endif
// Calculate IP pseudoheader checksum.
pseudoHeader.SourceAddress = remoteNode->IPAddr;
pseudoHeader.DestAddress.v[0] = destIP->v[0];
pseudoHeader.DestAddress.v[1] = destIP->v[1];
pseudoHeader.DestAddress.v[2] = destIP->v[2];
pseudoHeader.DestAddress.v[3] = destIP->v[3];
pseudoHeader.Zero = 0x0;
pseudoHeader.Protocol = IP_PROT_UDP;
pseudoHeader.Length = len;
SwapPseudoHeader(pseudoHeader);
checksum.Val = ~CalcIPChecksum((BYTE*)&pseudoHeader,
sizeof(pseudoHeader));
// Set UCP packet checksum = pseudo header checksum in MAC RAM.
IPSetRxBuffer(6);
MACPut(checksum.v[0]);
// In case if the end of the RX buffer is reached and a wraparound is needed, set the next address to prevent writing to the wrong address.
IPSetRxBuffer(7);
MACPut(checksum.v[1]);
IPSetRxBuffer(0); //Set current receive buffer access pointer to first byte of IP data = first byte of TCP header
// Now calculate UDP packet checksum in NIC RAM - including
// pesudo header.
checksum.Val = CalcIPBufferChecksum(len);
if ( checksum.Val != h.Checksum.Val )
{
MACDiscardRx(); //Discard the contents of the current RX buffer
return TRUE;
}
}
s = FindMatchingSocket(&h, remoteNode, destIP);
if ( s == INVALID_UDP_SOCKET )
{
// If there is no matching socket, There is no one to handle
// this data. Discard it.
MACDiscardRx(); //Discard the contents of the current RX buffer
}
else
{
UDPSocketInfo[s].RxCount = h.Length.Val;
UDPSocketInfo[s].Flags.bFirstRead = TRUE;
}
return TRUE;
}
