[PATCH] fix some parts of "samba-tool dns serverinfo ...."

[Jelmer Vernooij]

On Sun, Nov 09, 2014 at 09:39:20PM +0100, Günter Kukkukk wrote:
> Am 09.11.2014 um 14:01 schrieb Jelmer Vernooij:
> > On Sun, Nov 09, 2014 at 08:12:55AM +0100, Günter Kukkukk wrote:
> >> The attached patch fixes the IPv6 related infos in
> >>    samba-tool dns serverinfo <some-server>
> >>
> >> Due to many missing pieces in the samba code, the IPv6 info can
> >> atm only be queried from MS servers:
> >>
> >> The obviously *wrong* IPv6 display:
> >>   pszServerName               : w08r2.addlz.kukkukk.com
> >>   pszDsContainer              : cn=MicrosoftDNS,cn=System,DC=addlz,DC=kukkukk,DC=com
> >>   aipServerAddrs              : ['00:00:2a2:819:8f40:11e0:a1a2:fff8 (53)', '00:00:fd4d:e013:bb96:a6c:00:00 (53)', '00:00:fd4d:e013:bb96:a6c:a1a2:fff8
> >> (53)', '00:00:fe80:00:00:00:a1a2:fff8 (53)', '192.168.200.81 (53)']
> >>   aipListenAddrs              : ['00:00:fd4d:e013:bb96:a6c:00:00 (53)', '00:00:fe80:00:00:00:a1a2:fff8 (53)', '192.168.200.81 (53)']
> >>   aipForwarders               : ['192.168.200.70 (53)']
> >>
> >> Fixed one:
> >>
> >>   pszServerName               : w08r2.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:e013:bb96:a60c:0000:0000:0000:0051 (53)',
> >> 'fd4d:e013:bb96:a60c:a1a2:fff8:4aa6:3613 (53)', 'fe80:0000:0000:0000:a1a2:fff8:4aa6:3613 (53)', '192.168.200.81 (53)']
> >>   aipListenAddrs              : ['fd4d:e013:bb96:a60c:0000:0000:0000:0051 (53)', 'fe80:0000:0000:0000:a1a2:fff8:4aa6:3613 (53)', '192.168.200.81 (53)']
> >>   aipForwarders               : ['192.168.200.70 (53)']
> >>
> >> There are atm many missing pieces in the samba code regarding
> >>   - IPv4/IPv6 addresses available on the samba host
> >>   - IPv4/IPv6 addresses which samba bound to
> >>   - dynamically enable/disable bound interfaces
> >>   - ...
> >>
> >> The code is all there, but the API looks really strange to me.
> > We should really be using a standard formatting function for IPv6 addresses here.
> > For example, fd4d:e013:bb96:a60c:0000:0000:0000:0051 really should be formatted as 
> > fd4d:e013:bb96:a60c::51.
> > 
> > Cheers,
> > 
> > Jelmer
> > 
> 
> Hi Jelmer,
> 
> i've a question regarding the somewhat special case
> printing an IPv6 address when the available data
> is passed in an array of bytes. (MS-DNSP)
> 
> Afaik the usual python procedure would be like:
> 
> File "tstipv6.py:
> =================
> #!/usr/bin/python
> 
> import os
> import sys
> import socket
> 
> for addr in sys.stdin:
>   addr = addr.rstrip(os.linesep)
> 
>   try:
>     internal = socket.inet_pton(socket.AF_INET6, addr)
>     print socket.inet_ntop(socket.AF_INET6, internal)
> 
>   except socket.error:
>     print "Invalid address " + addr
> 
> ----------------------------------------------
> 
> echo '2001:db8:0:0:0:0:cafe:1111
> 2001:db8::a:1:2:3:4
> 2001:0DB8:AAAA:0000:0000:0000:0000:000C
> 2001:db8::1:0:0:0:4' | tstipv6.py
> 
> results to:
> 2001:db8::cafe:1111
> 2001:db8:0:a:1:2:3:4
> 2001:db8:aaaa::c
> 2001:db8:0:1::4
> 
> ------------------------------------------------
> But this approach cannot easily be used when the IPv6 data is passed
> in as an array of bytes:
>    print socket.inet_ntop(socket.AF_INET6, array_of_bytes)
> or can that data be easily casted or converted?
> 
> The passed in data has the following format
> struct DNS_ADDR {
>         uint8_t MaxSa[32];
>         uint32_t DnsAddrUserDword[8];
> };
> 
> where MaxSa[32] is the array of bytes.
> Offset | data
> 0:     | uint16_t  AddressFamily
> 2:     | uint16_t  PortNumber
> 4:     | uint32_t  IPv4Address
> 8:     | uint8_t   IPv6Address[16]
> ....
> 
> So the IPv6 address starts at MaxSa[8]

So, for starters, our Python bindings here are terrible. We should
actually be presenting them to the user in a way that they are familiar with.
So we should have a AddressFamily field, a portnumber field, an ipv4 address field
(that is a bytestring) and a ipv6 address field (that is also a bytestring).

That said, you can convert the byterray to a bytestring that inet_ntop
will understand by doing something like:

x = "".join([chr(b) for b in MaxSa])[8:]
print scoket.inet_ntop(socket.AF_INET6, x)

Hope this helps,

Jelmer