Changeset 304 for trunk

Timestamp:

04/16/12 18:14:44 (13 years ago)

Author:

Kris Deugau

Message:

/trunk

Drop support for /31 sub-octet ranges in in-addr.arpa zone names in
favour of supporting an alternate scheme that uses the netmask as
the number after the dash. (You can't tell 24-31 -> (range) .24/29
apart from 24-31 (mask) -> .24/31 in isolation.)

Consider supporting / in the zone name too; however / is not
generally considered a valid character for domain name parts.

[ log -> ticket fixup: see #26 ]

File:

• trunk/DNSDB.pm (modified) (2 diffs)

trunk/DNSDB.pm

@@ -846 +846 @@
 # Not quite a substitution sub, but placed here as it's basically the inverse of above;
 # given the .arpa zone name, return the CIDR netblock the zone is for.
-# Supports v4 non-octet/non-classful netblocks as per the method outlined in the Cricket Book (2nd Ed p217-218)
+# Supports v4 non-octet/non-classful netblocks as per the method outlined in the Grasshopper Book (2nd Ed p217-218)
 # Does NOT support non-quad v6 netblocks via the same scheme;  it shouldn't ever be necessary.
 # Takes a nominal .arpa zone name, returns a success code and NetAddr::IP, or a fail code and message
@@ -866 +866 @@
 
     # Map result of a range manipulation to a mask length change.  Cheaper than finding the 2-root of $octets[0]+1.
-    my %maskmap = (1 => 1, 3 => 2, 7 => 3, 15 => 4, 31 => 5, 63 => 6, 127 => 7);
+    # Note we will not support /31 blocks, mostly due to issues telling "24-31" -> .24/29 apart from
+    # "24-31" -> .24/31", with a litte bit of "/31 is icky".
+    my %maskmap = (  3 => 2,  7 => 3, 15 => 4, 31 => 5, 63 => 6, 127 => 7,
+                    30 => 2, 29 => 3, 28 => 4, 27 => 5, 26 => 6,  25 => 7
+        );
 
     # Handle "range" blocks, eg, 80-83.168.192.in-addr.arpa (192.168.80.0/22)
     # Need to take the size of the range to offset the basic octet-based mask length,
     # and make sure the first number in the range gets used as the network address for the block
+    # Alternate form:  The second number is actually the real netmask, not the end of the range.
     my $masklen = 0;
-    if ($octs[0] =~ /(\d+)-\d+/) {      # take the range...
-      $masklen -= $maskmap{-(eval $octs[0])};   # find the mask base...
+    if ($octs[0] =~ /(\d+)-(\d+)/) {    # take the range...
+      if (24 < $2 && $2 < 31) {
+        # we have a real netmask
+        $masklen = -$maskmap{$2};
+      } else {
+        # we have a range.  NB:  only real CIDR ranges are supported
+        $masklen -= $maskmap{-(eval $octs[0])}; # find the mask base...
+      }
       $octs[0] = $1;    # set the base octet of the range...
     }
     @octs = reverse @octs;      # We can reverse the octet pieces now that we've extracted and munged any ranges
+
+# arguably we should only allow sub-octet range/mask in-addr.arpa
+# specifications in the least significant octet, but the code is
+# simpler if we deal with sub-octet delegations at any level.
 
     # Now we find the "true" mask with the aid of the "base" calculated above