he.net: Add support for Hurricane Electric provider

The implementation is based on the existing
dyndns2 protocol with a few differences:
- The IPv4 and IPv6 addresses must be updated in
  separate calls. This is different from most of
  the other providers where both IPv4 and IPv6
  addresses can be updated in a single call. Thus
  the existing dyndns2 protocol implementation
  cannot be reused for dns.he.net.
- Multiple hosts are not supported by the provider.

See: https://dns.he.net/docs.html

ChangeLog.md

@@ -47,6 +47,8 @@ repository history](https://github.com/ddclient/ddclient/commits/master).
     [#676](https://github.com/ddclient/ddclient/pull/676)
   * `emailonly`: New `protocol` option that simply emails you when your IP
     address changes.  [#654](https://github.com/ddclient/ddclient/pull/654)
+  * `he.net`: Added support for updating Hurricane Electric records.
+    [#682](https://github.com/ddclient/ddclient/pull/682)
 
 ### Bug fixes
 
@@ -150,7 +152,7 @@ Refer to [v3.11 release plan discussions](https://github.com/ddclient/ddclient/i
 
   * Added support for domaindiscount24.com
   * Added support for njal.la
- 
+
 ## 2022-05-15 v3.10.0_2
 
 ### Bug fixes

README.md

@@ -33,6 +33,7 @@ Dynamic DNS services currently supported include:
 * [Gandi](https://gandi.net)
 * [GoDaddy](https://www.godaddy.com)
 * [Google](https://domains.google)
+* [Hurricane Electric](https://dns.he.net)
 * [Infomaniak](https://faq.infomaniak.com/2376)
 * [Loopia](https://www.loopia.se)
 * [Mythic Beasts](https://www.mythic-beasts.com/support/api/dnsv2/dynamic-dns)

ddclient.conf.in

@@ -222,6 +222,13 @@ ssl=yes					# use ssl-support.  Works with
 # password=my-auto-generated-password
 # my.domain.tld, otherhost.domain.tld
 
+##
+## Hurricane Electric (dns.he.net)
+##
+# protocol=he.net,                      \
+# password=my-genereated-password       \
+# myhost.example.com
+
 ##
 ## Duckdns (http://www.duckdns.org/)
 ##

ddclient.in

@@ -915,6 +915,17 @@ our %protocols = (
             'server'       => setv(T_FQDNP, 0, 0, 'domains.google.com', undef),
         },
     },
+    'he.net' => {
+        'updateable' => undef,
+        'update' => \&nic_henet_update,
+        'examples' => \&nic_henet_examples,
+        'variables' => {
+            %{$variables{'protocol-common-defaults'}},
+            'login' => undef,
+            'min-interval' => setv(T_DELAY, 0, 0, interval('5m'), 0),
+            'server' => setv(T_FQDNP, 0, 0, 'dyn.dns.he.net', undef),
+        },
+    },
     'hetzner' => {
         'force_update' => undef,
         'update'     => \&nic_hetzner_update,
@@ -5862,6 +5873,84 @@ sub nic_googledomains_update {
     }
 }
 
+######################################################################
+## nic_henet_examples
+##
+## written by Indrajit Raychaudhuri
+##
+######################################################################
+sub nic_henet_examples {
+    return <<"EoEXAMPLE";
+o 'he.net'
+
+The 'he.net' protocol is used by DNS service offered by dns.he.net.
+
+Configuration variables applicable to the 'he.net' protocol are:
+  protocol=he.net              ##
+  password=service-password    ## the password provided by the admin interface
+  fully.qualified.host         ## the host registered with the service.
+
+Example ${program}.conf file entries:
+  ## single host update
+  protocol=he.net,                                             \\
+  password=my-genereated-password                              \\
+  myhost.example.com
+EoEXAMPLE
+}
+
+######################################################################
+## nic_henet_update
+######################################################################
+sub nic_henet_update {
+    debug("\nnic_henet_update -------------------");
+
+    my %errors = (
+       'badauth' => 'Bad authorization (username or password)',
+       'badsys' => 'The system parameter given was not valid',
+       'nohost' => 'The hostname specified does not exist in the database',
+       'abuse' => 'The hostname specified is blocked for abuse',
+       'nochg' => 'No update required; unnecessary attempts to change to the current address are considered abusive',
+    );
+
+    for my $h (@_) {
+        # The IPv4 and IPv6 addresses must be updated in separate API call.
+        for my $ipv ('4', '6') {
+            my $ip = delete($config{$h}{"wantipv$ipv"}) or next;
+            info("Setting IPv%s address to %s for %s", $ipv, $ip, $h);
+            verbose("UPDATE:", "updating %s", $h);
+            my $reply = geturl(
+                proxy => opt('proxy'),
+                url => "https://$config{$h}{'server'}/nic/update?hostname=$h&myip=$ip",
+                login => $h,
+                password => $config{$h}{'password'},
+            ) // '';
+            if ($reply eq '') {
+                failed("updating %s: Could not connect to %s.", $h, $config{$h}{'server'});
+                next;
+            }
+            next if !header_ok($h, $reply);
+            # dyn.dns.he.net can return 200 OK even if there is an error (e.g., bad authentication,
+            # updates too frequent) so the body of the response must also be checked.
+            (my $body = $reply) =~ s/^.*?\n\n//s;
+            my ($line) = split(/\n/, $body, 2);
+            my ($status, $returnedip) = split(/ /, lc($line));
+            $status = 'good' if $status eq 'nochg';
+            $config{$h}{"status-ipv$ipv"} = $status;
+            if ($status ne 'good') {
+                if (exists($errors{$status})) {
+                    failed("updating %s: %s: %s", $h, $status, $errors{$status});
+                } else {
+                    failed("updating %s: unexpected status: %s", $h, $line);
+                }
+                next;
+            }
+            success("updating %s: %s: IPv%s address set to %s", $h, $status, $ipv, $returnedip);
+            $config{$h}{"ipv$ipv"} = $returnedip;
+            $config{$h}{'mtime'} = $now;
+        }
+    }
+}
+
 ######################################################################
 ## nic_mythicdyn_examples
 ##