Automatic Position Reporting System

aprs.ir3ip.net: the APRS server

Do you know that ir3ip is a APRS server?
Now there are several port available to the hamradio users, to exchange APRS traffic.
The main ports are:

10153

Transmit only APRS data of swiss, italian and slovenian stations.

10152

Transmit all world-wide APRS traffic

10151

Transmit all world-wide APRS traffic, and at the connection it also transmit the last 30 minutes of data

If you have installed APRSD server, and you are interested about knowing an easy way to filter data, just take a look at the following Tcl script:

#! /usr/bin/tclsh
#aprslocal: Tcl script which filter data read from APRSD daemon
#Called by xinetd superdaemon (file /etc/xinetd.d/aprslocal)
#service aprslocal
#{
#        socket_type             = stream
#        wait                    = no
#        user                    = nobody
#        server                  = /usr/local/bin/aprslocal
#        log_on_success          += USERID
#        log_on_failure          += USERID
#}
# Written by Paolo Subiaco iw3grx@ir3ip.net http://www.ir3ip.net/iw3grx
#

set sd [socket 44.134.177.204 10152]
fconfigure stdin  -blocking 0 ; #nonblocking stdin
for {set i 0} {$i<10} {incr i} {
        if {[gets stdin linein]>0} {
                puts $sd "$linein\r"
                flush $sd
        }
        if {[gets $sd line]>0} {
                puts "$line\r"
        }
}
while {[gets $sd line]>=0} {
  if {[regexp {^I|:I[0-Z]+|^T7|:T7|^HB9|:HB9|^S5[0-9]|:S5[0-9]|^OE[0-9]|:OE[0-9]|^9A[0-9]|:9A[0-9]} "$line"]} {
                puts "$line\r"
        }
        if {[gets stdin linein]>0} {
                puts $sd "$linein\r"
                flush $sd
        }
}

Do you think there will be several buffer overflows?
If you think so, please help me improving the script security! :-)

SuperVozelj telemetry transmission on APRS network

The small Perl script below permit to extract temperature information from svstat data file which may be transmitted on the APRS network as weather stations do.

The script may be called from the crontab:
59 * * * * /path/to/aprstelem.pl

Here is the perl script:

#! /usr/bin/perl
# Small script which read SuperVozelj temperature from svstat data, and send
# the telemetric information on APRS internet server aprsd
use Socket;
$aprsServer = "ir3ip.ampr.org";
$port = 1315;
$datapath="/home/iw3grx/svstat/dat/";
#$datapath="/home/iw3grx/projects/svstat/dat/";


($d1, $d2, $d3, $d4, $rawserver) = gethostbyname($aprsServer);
$serveraddr = pack("Sna4x8",2,$port,$rawserver);
$prototype = getprotobyname('udp');
socket(SOCKET,2,SOCK_DGRAM,$prototype) || die("No Socket\n");

$nodenum=0;
$callsign[$nodenum]="ir3cv";            # callsign in lowercase (as data filename)
$coord[$nodenum]="4603.50N/01218.10E_"; # Latitude/Longitude; '_' specify the WX symbol
$channel[$nodenum]=3;                   # Number of AD channel (from 1 to 11)
$qth[$nodenum]="Col Visentin";                                  # Node location
$altitude[$nodenum]=1760;                                                               # Node altitude (in metres)
$nodenum++;
$callsign[$nodenum]="ir3csm";
$coord[$nodenum]="4554.10N/01205.00E_";
$channel[$nodenum]=4;
$qth[$nodenum]="Col San Martino";
$altitude[$nodenum]=156;
$nodenum++;
$callsign[$nodenum]="ir3mco";
$coord[$nodenum]="4548.43N/01132.38E_";
$channel[$nodenum]=3;
$qth[$nodenum]="Monte Corno";
$altitude[$nodenum]=1350;
$nodenum++;
$callsign[$nodenum]="ir3fon";
$coord[$nodenum]="4606.30N/01307.10E_";
$channel[$nodenum]=3;
$qth[$nodenum]="Savalons";
$altitude[$nodenum]=105;
$nodenum++;


($sec,$min,$hour,$mday,$mon,$year,$wday,$yday)=gmtime();
$now=time();

for ($i=0; $i<$nodenum; $i++) {
  $filename=$datapath.$callsign[$i].".dat";
  if (!open($fd,$filename)) {
    # Error opening data file
    printf(stderr "Data file %s does not exist or is not readable!\n",$filename);
    next;
  }
  # must be improved (read in the file header): $size=48
  $size=48;
  seek($fd,-1*$size,2);
  if (read($fd,$buffer,4)!=4) {
    # Error reading the first 4 bytes (timestamp)
    printf(stderr "Error reading timestamp from data file %s!\n",$filename);
    close($fd);
    next;
  }
        $time=unpack("I",$buffer);
  if (abs($now-$time) > 9000) {
    printf(stderr "Temperature from %s node is too old (%d seconds)\n",$callsign[$i],($now-$time));
    close($fd);
    next;
  }
  if ($channel[$i]>1) {
    seek($fd,4*($channel[$i]-1),1);
  }
  if (read($fd,$buffer,4)!=4) {
    # Error reading temperature value
    printf(stderr "Error reading temperature value from data file %s!\n",$filename);
    close($fd);
    next;
  }
        $temp=unpack("f",$buffer);
  $message=sprintf("%s>APWX,WIDE:@%02d%02d%02dz%s.../...g...t%03d\0",
    uc($callsign[$i]),$mday,$hour,$min,$coord[$i],int($temp*1.8+32));
  send(SOCKET,$message,0,$serveraddr);
  $message=sprintf("%s>APWX,WIDE:@%02d%02d%02dz%s/A=%06d SuperVozelj node %s, %dm asl\0",
                uc($callsign[$i]),$mday,$hour,$min,$coord[$i],$altitude[$i]/0.305,$qth[$i],$altitude[$i]);
        send(SOCKET,$message,0,$serveraddr);
        close($fd);
}