Once again syncing after too long an absence

[p5sagit/p5-mst-13.2.git] / lib / Net / Ping.pm

diff --git a/lib/Net/Ping.pm b/lib/Net/Ping.pm
index 40da9f3..a2846fe 100644 (file)
--- a/lib/Net/Ping.pm
+++ b/lib/Net/Ping.pm
@@ -269,13 +269,13 @@ sub checksum
         );
 
     $len_msg = length($msg);
-    $num_short = $len_msg / 2;
+    $num_short = int($len_msg / 2);
     $chk = 0;
     foreach $short (unpack("S$num_short", $msg))
     {
         $chk += $short;
     }                                           # Add the odd byte in
-    $chk += unpack("C", substr($msg, $len_msg - 1, 1)) if $len_msg % 2;
+    $chk += (unpack("C", substr($msg, $len_msg - 1, 1)) << 8) if $len_msg % 2;
     $chk = ($chk >> 16) + ($chk & 0xffff);      # Fold high into low
     return(~(($chk >> 16) + $chk) & 0xffff);    # Again and complement
 }
@@ -369,16 +369,17 @@ sub ping_udp
         elsif ($nfound)         # A packet is waiting
         {
             $from_msg = "";
-            $from_saddr = recv($self->{"fh"}, $from_msg, 1500, $flags);
-            ($from_port, $from_ip) = sockaddr_in($from_saddr);
-            if (($from_ip eq $ip) &&        # Does the packet check out?
-                ($from_port == $self->{"port_num"}) &&
-                ($from_msg eq $msg))
-            {
-                $ret = 1;       # It's a winner
-                $done = 1;
-            }
-        }
+            $from_saddr = recv($self->{"fh"}, $from_msg, 1500, $flags)
+               or last; # For example an unreachable host will make recv() fail.
+           ($from_port, $from_ip) = sockaddr_in($from_saddr);
+           if (($from_ip eq $ip) &&        # Does the packet check out?
+               ($from_port == $self->{"port_num"}) &&
+               ($from_msg eq $msg))
+           {
+               $ret = 1;       # It's a winner
+               $done = 1;
+           }
+       }
         else                    # Oops, timed out
         {
             $done = 1;
@@ -459,6 +460,11 @@ received from the remote host and the received packet contains the
 same data as the packet that was sent, the remote host is considered
 reachable.  This protocol does not require any special privileges.
 
+It should be borne in mind that, for both tcp and udp ping, a host
+will be reported as unreachable if it is not running the
+appropriate echo service.  For Unix-like systems see L<inetd(8)> for
+more information.
+
 If the "icmp" protocol is specified, the ping() method sends an icmp
 echo message to the remote host, which is what the UNIX ping program
 does.  If the echoed message is received from the remote host and