You are here: Appendices > Appendix W Moab Resource Manager Language Interface Overview > Moab RM Language Socket Protocol Description

W.3 Moab RM Language Socket Protocol Description

Moab RM language is formerly known as WIKI. The Moab scheduler uses a simple protocol for socket connections to the user client and the resource manager as described below:

Attribute	Description
<SIZE>	8 character decimal ASCII representation of the size of the packet following '<SIZE><CHAR>' Leading zeroes must be used to pad this value to 8 characters if necessary.
<CHAR>	A single ASCII character
<CKSUM>	A 16 character hexadecimal ASCII DES-based checksum calculated using the algorithm below* and <SEED> selected and kept secret by the site admins. The checksum is performed on the line from TS= to the end of the message including <DATA>.
<WS>	a series of white space characters consisting of either tabs and/or space characters.
<TIMESTAMP>	ASCII representation of epoch time
<AUTH>	Identifier of user requesting service (i.e., USERNAME)
<DT>	Data to be sent

An example header follows:

00001057 CK=cdf6d7a7ad45026f TS=922401962 AUTH=sched DT=<DATA>

where <DATA> is replaced by actual message data.

W.3.1 Checksum Algorithm ('C' version)

#define MAX_CKSUM_ITERATION 4

int GetChecksum(
 char *Buf,
 int BufSize,
 char *Checksum,
 char *CSKey) /* Note: pass in secret key */
 {
 unsigned int crc;
 unsigned int lword;
 unsigned int irword;
 int index;
 unsigned int Seed;
 Seed = (unsigned int)strtoul(CSKey,NULL,0);
 crc = 0;
 for (index = 0;index < BufSize;index++)
 {
 crc = (unsigned int)DoCRC((unsigned short)crc,Buf[index]);
 }
 lword = crc;
 irword = Seed;
 PSDES(&lword,&irword);
 sprintf(Checksum,"%08x%08x",
 lword,
 irword);
 return(SUCCESS);
 }


unsigned short DoCRC(
 unsigned short crc,
 unsigned char onech)
 {
 int index;
 unsigned int ans;
 ans = (crc ^ onech << 8);
 for (index = 0;index < 8;index++)
 {
 if (ans & 0x8000)
 ans = (ans <<= 1) ^ 4129;
 else
 ans <<= 1;
 }
 return((unsigned short)ans);
 }


int PSDES(
 unsigned int *lword,
 unsigned int *irword)
 {
 int index;
 unsigned int ia;
 unsigned int ib;
 unsigned int iswap;
 unsigned int itmph;
 unsigned int itmpl;
 static unsigned int c1[MAX_CKSUM_ITERATION] = {
 0xcba4e531, 0x537158eb, 0x145cdc3c, 0x0d3fdeb2 };
 static unsigned int c2[MAX_CKSUM_ITERATION] = {
 0x12be4590, 0xab54ce58, 0x6954c7a6, 0x15a2ca46 };
 itmph = 0;
 itmpl = 0;
 for (index = 0;index < MAX_CKSUM_ITERATION;index++)
 {
 iswap = *irword;
 ia = iswap ^ c1[index];
 itmpl = ia & 0xffff;
 itmph = ia >> 16;
 ib = (itmpl * itmpl) + ~(itmph*itmph);
 ia = (ib >> 16) | ((ib & 0xffff) << 16);
 *irword = (*lword) ^ ((ia ^ c2[index]) + (itmpl * itmph));
 *lword = iswap;
 }
 return(SUCCESS);
 }

W.3.2 Header Creation (PERL code)

(taken from PNNL's QBank client code)

################################################################################
#
# subroutine wiki($COMMAND)
#
# Sends command to Moab server and returns the parsed result and status
#
################################################################################
sub wiki
{
 my($COMMAND,$REQUEST,$result);
 my($sockaddr,$hostname);
 my($name,$aliases,$proto,$port,$type,$len,$thisaddr);
 my($thisport,$thatport,$response,$result);
 $COMMAND = shift;
 #
 # Establish socket connection
 #
 $sockaddr = 'S n a4 x8';
 chop ($hostname = `hostname`);
 ($name,$aliases,$proto)=getprotobyname('tcp');
 ($name,$aliases,$type,$len,$thisaddr)=gethostbyname($hostname);
 ($name,$aliases,$type,$len,$thataddr)=gethostbyname($BANKHOST);
 $thisport=pack($sockaddr, &AF_INET,0,$thisaddr);
 $thatport=pack($sockaddr, &AF_INET,$BANKPORT,$thataddr);
 socket(S, &PF_INET,&SOCK_STREAM,$proto) || die "cannot create socket\n";
 bind(S,$thisport) || die "cannot bind socket\n";
 connect(S,$thatport) || die "cannot connect socket\n";
 select(S); $| = 1; # Turn on autoflushing
 select(stdout); $| = 1; # Select STDOUT as default output
 #
 # Build and send command
 #
 $REQUEST="COMMAND=$COMMAND AUTH=$AUTH";
 chomp($CHECKSUM = `$QSUM "$REQUEST"`);
 $REQUEST .= " CHECKSUM=$CHECKSUM";
 my $command=pack "a8 a1 A*",sprintf("%08d",length($REQUEST))," ",$REQUEST;
 print S "$command"; # Send Command to server
 @REPLY=();
 while () { push(@REPLY,$_); } # Listen for Reply
 $STATUS=grep(/STATUSCODE=(\d*)/&&$1,@REPLY); # STATUSCODE stored in $STATUS
 grep(s/.*RESULT=//,@REPLY); # Parse out the RESULT
 return @REPLY;
}

W.3.3 Header Processing (PERL code)

sysread(NS,$length,8); # Read length string
sysread(NS,$delimiter,1); # Read delimiter byte
$DEBUG && print STDERR "length=[$length]\tdelimiter=[$delimiter]\n";
while($length) {
 $DEBUG && print STDERR "Awaiting $length bytes -- ".`date`;
 $length-=sysread(NS,$request,$length); # Read request
 sleep 1;
 }
%REQUEST=();
chomp($request);
foreach (@REQUEST=&shellwords($request)) # Parse arguments into array
 {
 ($key,$value)=split(/=/,$_);
 $REQUEST{$key}=$value unless defined $REQUEST{$key};
 }
$request =~ s/\s+CHECKSUM=.*//; # Strip off the checksum
print STDERR "REQUEST=$request\n";
chomp($checksum=`$QSUM "$request"`);
$me=$REQUEST{AUTH};
$command=$REQUEST{COMMAND};
if (!grep($command eq $_,@VALIDCMDS))
 { $REPLY = "STATUSCODE=0 RESULT=$command is not a valid command\n";}
elsif ($checksum ne $REQUEST{CHECKSUM})
 { $REPLY = "STATUSCODE=0 RESULT=Invalid Checksum\n";}
else
 { $REPLY = do $command(@REQUEST); }
$len=sprintf("%08d",length($REPLY)-1);
$delim=' ';
$DEBUG && print STDERR "REPLY=${len}${delim}$REPLY\n";
$buf="$len"."$delim"."$REPLY";
syswrite(NS,$buf,length($buf));
close NS;