On Friday 02 July 2004 04:25 am, Gaurav Mengi wrote:
> Hi Annada,
> I was waiting for some pointers from ur side...
>
> As u have mentioned I had already done that......
>
> I'll be glad If u can send me the code(snapshot) of N/w Programming using
> UDP Sockets which works successfully on the device...........especially
> the snapshot of that code where ur receiving the message
In case it helps. Here is what I've used. Ignore the DNS cache stuff.
This gives a random receive port. From my server I reply to whatever port
the packet indicates.
I noticed that in your code you don't NetLibSocketConnect(). This may not
be required with UDP, but I wouldn't be surprised if PalmOS gets messed up
without it.
Int16 connectsockudp(char *host, char *service, UInt16 refnum, Int32 timeout)
{
NetSocketRef sock;
Int16 one;
Int16 i1;
NetSocketAddrINType saddr;
NetHostInfoPtr phe;
NetHostInfoBufType AppHostInfo;
Boolean nameresolved=false;
UInt32 hosthash;
one = 1;
MemSet((char *) &saddr, sizeof(saddr), 0);
saddr.family = netSocketAddrINET;
saddr.port = NetHToNS(StrAToI(service));
if ((sock = NetLibSocketOpen(refnum, netSocketAddrINET,
netSocketTypeDatagram, 0, timeout, &errno)) < 0) {
return 0;
}
/* see if we can use our DNS cache */
if (!FtrGet(MainAppID, FTR_HOSTHASH, &hosthash) &&
(rotating_hash(host, StrLen(host)) == hosthash) &&
!FtrGet(MainAppID, FTR_HOSTIP, (UInt32 *)&saddr.addr)) {
nameresolved = true;
}
/*
* Map host name to IP address, allowing for dotted decimal.
* I try to assimilate the name first to see if it is just
* a dotted IP. If not, then I use the DNS to resolve.
*
* Also it tries to retrieve a cached IP from a feature.
*/
if (!nameresolved ||
((saddr.addr = NetLibAddrAToIN(refnum, host)) == -1)) {
if ((phe = NetLibGetHostByName(refnum, host, &AppHostInfo,
timeout, &errno)) != 0) {
/*
* Sometimes the first address in the list is zero. This
* makes me have to search through them to find the first
* non-zero address.
*/
for (i1=0; i1 < netDNSMaxAddresses; i1++) {
if (phe->addrListP[i1] != NULL) {
if (*phe->addrListP[i1] != '\0') {
MemMove((char *) &saddr.addr,
(char *) phe->addrListP[i1], phe->addrLen);
nameresolved = true;
break;
}
}
}
}
if (!nameresolved) {
NetLibSocketClose(refnum, sock, timeout, &errno);
return 0;
} else {
/*
* Cache the IP to make future lookups quicker. Note that
* I store a hash of the hostname only to validate the need for
* an uncached DNS lookup later.
*/
FtrSet(MainAppID, FTR_HOSTHASH, rotating_hash(host,
StrLen(host)));
FtrSet(MainAppID, FTR_HOSTIP, (UInt32)saddr.addr);
}
}
if (NetLibSocketConnect(refnum, sock, (NetSocketAddrType *) &saddr,
sizeof(saddr), timeout, &errno) != 0) {
NetLibSocketClose(refnum, sock, timeout, &errno);
return 0;
}
/* set to non-blocking */
NetLibSocketOptionSet(refnum, sock, netSocketOptLevelSocket,
netSocketOptSockNonBlocking, &one, sizeof(one), timeout, &errno);
/* turn off Nagle */
NetLibSocketOptionSet(refnum, sock, netSocketOptLevelTCP,
netSocketOptTCPNoDelay, &one, sizeof(one), timeout, &errno);
/*
* This usually fails in the emulator. It's needed to have PalmOS
* assign a non-zero source port.
*/
MemSet((char *) &saddr, sizeof(saddr), 0);
NetLibSocketBind(refnum, sock, (NetSocketAddrType *) &saddr,
sizeof(saddr), timeout, &errno);
return sock;
}
An example of receiving a UDP packet:
NetFDSetType rfds, wfds;
unsigned char buf[32];
netFDZero(&rfds);
netFDZero(&wfds);
netFDSet(sysFileDescStdIn, &rfds);
netFDSet(udpsock, &rfds);
rv = NetLibSelect(appref, netFDSetSize, &rfds, &wfds, NULL, tp,
&err);
if ((rv > 0) && netFDIsSet(udpsock, &rfds) &&
((bytes = NetLibReceive(appref, udpsock, buf,
sizeof(buf), 0, 0, 0, 1, &err)) == 16) &&
(buf[0] == 0xa5) && (buf[1] == 0x5a)) {
ispacket = true;
/* success */
if (buf[6] == 1) ismail = true; /* now we'll do a full POP */
break;
}
--
/* Chris Faherty <[EMAIL PROTECTED]> */
--
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