From b2982f5b324ee910847e28d76652c74576b8ed8e Mon Sep 17 00:00:00 2001
From: Dirk Koopman <djk@tobit.co.uk>
Date: Fri, 3 Mar 2023 14:22:54 +0000
Subject: [PATCH] add user level ping as link check command

---
 Changes             |  4 ++++
 cmd/Commands_en.hlp | 21 +++++++++++++++++++++
 cmd/ping.pl         | 46 ++++++++++++++++++++++++++++++---------------
 3 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/Changes b/Changes
index 9d9e2466..8ee7916f 100644
--- a/Changes
+++ b/Changes
@@ -2,6 +2,10 @@
 1. Fix DXDebug::DXDebug not found errors in rarely used functions. This is 
    also an interaction with differing versions of Mojolicious. Clearly this 
    has never happened to me (sigh).
+2. Allow non-privileged users to use ping (no arguments) and get 'PONG nn' 
+   where nn is an incrementing counter or if there is an argument it will 
+   return 'PONG <argument>' - all in UPPER CASE. See help ping for more
+   details. 
 02Mar23=======================================================================
 1. Fix sh/dx/30 problem. I.e. allow old style version of sh/dx 30.  
 01Mar23=======================================================================
diff --git a/cmd/Commands_en.hlp b/cmd/Commands_en.hlp
index 909c3b7d..63cef603 100644
--- a/cmd/Commands_en.hlp
+++ b/cmd/Commands_en.hlp
@@ -1128,6 +1128,27 @@ PC protocol to connected nodes either for testing or to unstick things.
 You can also use in the same way as a talk command to a connected user but
 without any processing, added of "from <blah> to <blah" or whatever.
  
+=== 0^PING [argument]^User level link check command
+At the user level, this command allows the user to check that they
+are still connected to a functioning node. If the command is
+issued with no arguments it will return string 'PONG 123' where
+'123' is a node global counter starting at 1. This number cannot
+be relied to run consecutively as it is shared by all users.
+
+If an argument is supplied then the return is 'PONG ARGUMENT'. So it
+you are a client program and you need a counter or some other unique
+string to satisfy yourself that you are not being spoofed, then you
+will need to supply the argument and check that reply is what you
+expect:
+
+ping 23 or ping xyzzy
+
+will return
+
+PONG 23 or PONG XYZZY
+
+respectively.
+
 === 1^PING <node call>^Check the link quality between nodes
 This command allows you to send a frame to another cluster node on
 the network and get a return frame.  The time it takes to do this
diff --git a/cmd/ping.pl b/cmd/ping.pl
index 32efda31..89f43a0b 100644
--- a/cmd/ping.pl
+++ b/cmd/ping.pl
@@ -6,27 +6,43 @@
 #
 #
 
-my $self = shift;
-my $line = uc shift;   # only one callsign allowed 
-my ($call) = $line =~ /^\s*(\S+)/;
+my $counter;
 
-# are we permitted?
-return (1, $self->msg('e5')) if $self->priv < 1;
+sub init
+{
+	$counter = 0;
+}
 
-# is there a call?
-return (1, $self->msg('e6')) if !$call;
+sub handle
+{
+	my $self = shift;
+	my $line = uc shift;		# only one callsign allowed 
+	my ($call) = $line =~ /^\s*(\S+)/;
 
-# is it me?
-return (1, $self->msg('pinge1')) if $call eq $main::mycall;
+#	$DB::single = 1;
 
-# can we see it? Is it a node?
-my $noderef = Route::Node::get($call);
+	if ($self->{priv} < 1) {
+		if ($call) {
+			return (1, "PONG $call");
+		}
+		++$counter, return (1, "PONG $counter") 
+	}
 
-return (1, $self->msg('e7', $call)) unless $noderef;
+	# is there a call?
+	return (1, $self->msg('e6')) if !$call;
 
-# ping it
-DXXml::Ping::add($self, $call);
+	# is it me?
+	return (1, $self->msg('pinge1')) if $call eq $main::mycall;
 
-return (1, $self->msg('pingo', $call));
+	# can we see it? Is it a node?
+	my $noderef = Route::Node::get($call);
+
+	return (1, $self->msg('e7', $call)) unless $noderef;
+
+	# ping it
+	DXXml::Ping::add($self, $call);
+
+	return (1, $self->msg('pingo', $call));
+}
 
 
-- 
2.43.0