General question - here about python/samba/netcmd/dns.py

[Günter Kukkukk]

Hi all,

just a general question, how to proceed when we seem to violate
some MS documentation - probably here a silly case.
Here it's about MS claims "...MUST ignore it"

When using
  samba-tool dns serverinfo w2008r2
i noticed that the displayed IPv6 addresses were wrong - see below.


python/samba/netcmd/dns.py
.....
I already fixed
   - the IPv6 format string ('%x%x:... to '%02x%02x:...')
   - the IPv6 array offsets from MaxSa[4:20] to MaxSa[8:24]
but then started wondering about the port-number (2 bytes) being placed at
   MaxSa[3] <= would be big-endian
but the Address Family (0x0002 or 0x0017) is placed at
   MaxSa[0] <= would be small-endian

Note that both "Address Family" and "Port Number" are 16Bit.

Then i looked at the MS specs in [MS-DNSP].pdf (btw - there is
an updated version from 15th May 2014)

2.2.3.2.2.1 DNS ADDR

"Port Number (2 bytes): Senders MUST set this to zero, and receivers MUST ignore it."



 ------- current fix - but still uses the port number:
def dns_addr_array_string(array):
    ret = []
    if not array:
        return ret
    for i in xrange(array.AddrCount):
        if array.AddrArray[i].MaxSa[0] == 0x02:
            addr = '%d.%d.%d.%d (%d)' % \
                tuple(array.AddrArray[i].MaxSa[4:8] + [array.AddrArray[i].MaxSa[3]])
        elif array.AddrArray[i].MaxSa[0] == 0x17:
            addr = '%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x (%d)' % \
                tuple(array.AddrArray[i].MaxSa[8:24] + [array.AddrArray[i].MaxSa[3]])
        else:
            addr = 'UNKNOWN'
        ret.append(addr)
    return ret
----------------

samba-tool dns serverinfo w2008r2

w2008r2 with IPv6 format string fixed, but with wrong array indices:
------------------
  pszServerName               : w2008r2.addlz.kukkukk.com
  pszDsContainer              : cn=MicrosoftDNS,cn=System,DC=addlz,DC=kukkukk,DC=com
  aipServerAddrs              : ['0000:0000:2a02:8109:8f40:11e0:a1a2:fff8 (53)', '0000:0000:fd4d:bf13:bb76:c903:0000:0000 (53)',
'0000:0000:fd4d:bf13:bb76:c903:a1a2:fff8 (53)', '0000:0000:fe80:0000:0000:0000:a1a2:fff8 (53)', '192.168.200.81 (53)']
  aipListenAddrs              : []
  aipForwarders               : ['192.168.200.70 (53)', '0000:0000:2a02:8109:8f40:107c:020c:29ff (53)']
  dwLogLevel                  : 0

 w2008r2 IPv6 output fixed:
  ----------------
  pszServerName               : w2008r2.addlz.kukkukk.com
  pszDsContainer              : cn=MicrosoftDNS,cn=System,DC=addlz,DC=kukkukk,DC=com
  aipServerAddrs              : ['2a02:8109:8f40:11e0:a1a2:fff8:4aa6:3613 (53)', 'fd4d:bf13:bb76:c903:0000:0000:0000:0051 (53)',
'fd4d:bf13:bb76:c903:a1a2:fff8:4aa6:3613 (53)', 'fe80:0000:0000:0000:a1a2:fff8:4aa6:3613 (53)', '192.168.200.81 (53)']
  aipListenAddrs              : []
  aipForwarders               : ['192.168.200.70 (53)', '2a02:8109:8f40:107c:020c:29ff:fe3b:8649 (53)']
  dwLogLevel                  : 0

  Samba atm only checks for IPv4 interfaces, which also goes wrong - but that has to be another fix:
  --------------
  pszServerName               : LI4771-131.addlz.kukkukk.com
  pszDsContainer              : CN=MicrosoftDNS,DC=DomainDnsZones,DC=addlz,DC=kukkukk,DC=com
  aipServerAddrs              : ['255.255.255.255 (53)', '255.255.255.255 (53)', '255.255.255.255 (53)', '255.255.255.255 (53)']
  aipListenAddrs              : ['255.255.255.255 (53)', '255.255.255.255 (53)', '255.255.255.255 (53)', '255.255.255.255 (53)']
  aipForwarders               : []
  dwLogLevel                  : 0
-----------------------

see also dnsdata.c ---> ip4_array_to_dns_addr_array()
and dnsutils.c
-------------------

So finally now my question:  :-)
Should we remove all references to this port specification - here in python and
also in the C-Code, where it is set?

Thanks, Günter

ps - sorry for the long post

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