I am observing a problem in the TCP/IP stack when attempting to write data
to a non-blocking TCP/IP stream socket immediately after NetLibSelect
indicates that the socket is writeable (following a connect). In this case
NetLibSend returns with err = netErrSocketNotConnected; If, however, I
introduce a 20-tick delay (via SysTaskDelay(20)) between the NetLibSelect
call that indicated completion of connection-establishment and the first
NetLibSend call, then everything seems to work. I am observing this on both
PalmOS v3.1 and v3.5.
The code snippets are at the end.
Thank you,
Vitaly
void test (void)
{
...
s = PrvTCPSocketOpenNB (&err);
PrvSocketConnect (s, ipAddrNetByteOrder, portNetByteOrder, &err);
netFDZero (&readFDs);
netFDZero (&writeFDs);
netFDZero (&exceptFDs);
netFDSet (netIfP, s, &writeFDs);
result = NetLibSelect (gP->netLibRefNum, netFDSetSize,
NULL, writeFDsP, NULL,
timeout,
&err);
// Check for error
if (result < 0)
{
goto Exit;
}
// Check for timeout
if (result == 0)
{
goto Exit;
}
if (!netFDIsSet(s, &writeFDs))
{
goto Exit; // writeable is not set, therefore no connection
}
// SysTaskDelay(20); // <-- UNCOMMENTING THIS APPEARS TO FIX THE PROBLEM
numSent = NetLibSend (gP->netLibRefNum, socket,
bufP, bufLen, 0 /*flags*/,
NULL /*toAddrP*/, 0
/*toLen*/,
-1 /*timeout*/, &err);
// here we usually end up with netErrSocketNotConnected, unless the
SysTaskDelay(20) call
// above is enabled.
}
// Create a non-blocking socket
static NetSocketRef
PrvTCPSocketOpenNB (Err* errP)
{
NetSocketRef s = -1;
Boolean nonBlockingOn;
*errP = 0;
// Create a TCP/IP socket
s = NetLibSocketOpen (gP->netLibRefNum, netSocketAddrINET,
netSocketTypeStream, 0, -1
/*timeout*/, errP);
if (s < 0)
{
return (s);
}
// Place socket into non-blocking mode
nonBlockingOn = true;
NetLibSocketOptionSet (gP->netLibRefNum, s, netSocketOptLevelSocket,
netSocketOptSockNonBlocking, &nonBlockingOn,
sizeof(nonBlockingOn), -1
/*timeout*/, errP);
return (s);
} // PrvTCPSocketOpenNB
// Connect a non-blocking socket
static Int16
PrvSocketConnect (NetSocketRef socket,
NetIPAddr inet, UInt16 port, Err*
errP)
{
Int16 result;
NetSocketAddrINType addrIN;
*errP = 0;
// Initiate connection
addrIN.family = netSocketAddrINET; // hbo
addrIN.addr = inet; // nbo
addrIN.port = port; // nbo
result = NetLibSocketConnect (gP->netLibRefNum, socket,
(NetSocketAddrType*)&addrIN, sizeof(addrIN),
-1
/*timeout*/, errP);
if (result < 0)
return (result);
} // PrvSocketConnect
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