add dry-run, and use reverse DNS for fixup

Pipfile

@@ -9,6 +9,7 @@ verify_ssl = true
 librouteros = "==3.*"
 progress = "*"
 pyyaml = "*"
+dnspython = "*"
 
 [requires]
 python_version = "3.8"

automonty

@@ -7,6 +7,7 @@ import ssl
 import os
 import yaml
 import re
+import dns.resolver, dns.reversename
 
 # comment format:
 # hostname.example.com [aM flag1 flag2 key1=value1 key2=option3:value3,option4:value4] selector.example.com
@@ -44,6 +45,12 @@ def parse_comment( comment ):
     else:
         return ( None, None, comment )
 
+def reverse_dns( address ):
+    try:
+        return str( dns.resolver.resolve( dns.reversename.from_address( address ), 'PTR' )[ 0 ] )
+    except:
+        return address
+
 def make_comment( selector, rval, hostname ):
     rvalbits = [ "aM" ]
     for ( k, v ) in rval.items():
@@ -105,23 +112,39 @@ def monty_check( config, args, routers ):
                     print( name, ": v6", 'ENABLED' if active else 'disabled', item[ 'interface' ] )
 
 def monty_fixup( config, args, routers ):
+    reverse = {}
+    statics = {}
     for ( name, api ) in routers.items():
         ip_address = api.path( 'ip', 'address' )
         ipv6_address = api.path( 'ipv6', 'address' )
         for item in ip_address:
-            if item[ 'interface' ].startswith( "loop" ):
-                continue
-            if item[ 'address' ] not in config[ 'loopbacks' ]:
-                continue
             ( sel, rval, hst ) = parse_comment( item.get( 'comment', '' ) )
             if sel is None:
                 rval = {}
                 active = not item[ 'disabled' ] and not item[ 'invalid' ]
-                if active:
-                    rval[ 'home' ] = True
-                new_comment = make_comment( hst, rval, hst )
-                print( name, ":", item[ 'interface' ], new_comment )
-                ip_address.update( **{ 'comment': new_comment, '.id': item[ '.id' ] } )
+                if item[ 'address' ] in config[ 'loopbacks' ]:
+                    if active:
+                        rval[ 'home' ] = True
+                else:
+                    rval[ 'static' ] = True
+                    statics[ item[ 'interface' ] ] = True
+                if not hst:
+                    hst = reverse_dns( item[ 'network' ] )
+                    while hst.endswith( "." ):
+                        hst = hst[ :-1 ]
+                if not sel:
+                    if item[ 'interface' ] not in reverse:
+                        rev = reverse_dns( item[ 'network' ] )
+                        while rev.endswith( "." ):
+                            rev = rev[ :-1 ]
+                        reverse[ item[ 'interface' ] ] = rev
+                    sel = rev
+                new_comment = make_comment( sel, rval, hst )
+                if args.dry_run:
+                    print( item[ 'interface' ], item[ 'address' ], '->', new_comment )
+                else:
+                    print( name, ":", item[ 'interface' ], new_comment )
+                    ip_address.update( **{ 'comment': new_comment, '.id': item[ '.id' ] } )
         for item in ipv6_address:
             if item[ 'interface' ].startswith( "loop" ):
                 continue
@@ -131,11 +154,20 @@ def monty_fixup( config, args, routers ):
             if sel is None:
                 rval = {}
                 active = not item[ 'disabled' ] and not item[ 'invalid' ]
-                if active:
+                if statics.get( item[ 'interface' ], False ):
+                    rval[ 'static' ] = True
+                elif active:
                     rval[ 'home' ] = True
-                new_comment = make_comment( hst, rval, hst )
-                print( name, ":", item[ 'interface' ], new_comment )
-                ipv6_address.update( **{ 'comment': new_comment, '.id': item[ '.id' ] } )
+                if not sel:
+                    sel = reverse.get( item[ 'interface' ], "XXX " + item[ 'interface' ] )
+                if not hst:
+                    hst = reverse.get( item[ 'interface' ], "XXX " + item[ 'interface' ] )
+                new_comment = make_comment( sel, rval, hst )
+                if args.dry_run:
+                    print( item[ 'interface' ], item[ 'address' ], '->', new_comment )
+                else:
+                    print( name, ":", item[ 'interface' ], new_comment )
+                    ipv6_address.update( **{ 'comment': new_comment, '.id': item[ '.id' ] } )
 
 def load_configuration():
     try:
@@ -153,6 +185,7 @@ def main():
     subparsers = parser.add_subparsers()
 
     parser.add_argument( '--only', action = 'append' )
+    parser.add_argument( '-n', '--dry-run', action = 'store_true' )
 
     parser_check = subparsers.add_parser( 'check' )
     parser_check.add_argument( 'addr', nargs = "*" )