Re: IPv6 ranges

[Xu Weilin <mzweilin () gmail com>]

Yes, it's reasonable to implement IPv6 ranges first. I forgot that we hadn't
implement the basic parsing of IPv6 CIDR before.

Now I should spend some time on learning NSE script.

On Thu, Jun 23, 2011 at 8:16 AM, David Fifield <david () bamsoftware com>wrote:

> Weilin,
>
> I think that we must implement IPv6 ranges before doing multicast host
> discovery. The reason for this is that I think it only makes sense to
> use multicast when dealing with a whole network.
>
> Currently Nmap's model is to parse the command-line host specifications,
> return one host at a time (see TargetGroup::get_next_host), and then
> feed those (4096 at a time) into ping scan. We need to change that, so
> that we can feed an entire block like fe80::/64 into ping scan when
> appropriate, without enumerating 2^64 addresses.
>
> Colin has done the first steps towards this model. Please see the code
> in nbase/nbase_addrset.c. This code can store IPv4 ranges and IPv6
> networks with netmasks, without using very much space. We already use
> this new code for Nmap's --exclude option.
>
> The addrset code does not yet support iteration over members. We need to
> make it do that, but it must be capable of returning entire blocks when
> asked. For example, given the address specifications
>        ::1 fe80::/64 1:2:3::4:5:6 scanmev6.nmap.org/112
> the iteration would return the single host ::1, the network fe80::/64,
> the single host 1:2:3::4:5:6, and the network
> 2600:3c01::f03c:91ff:fe93:cd19/112. The next higher level would see:
>        * ::1 as a localhost address (and not ping it),
>        * fe80::/64 as a local network (and do multicast ping on it),
>        * 1:2:3::4:5:6 as a single IP address (and do unicast ping on it),
> and
>        * 2600:3c01::f03c:91ff:fe93:cd19/112 as a remote network (which it
>          would then further iterate into 256 unicast hosts).
>
> I want to suggest that you first implement these multicast host
> discovery probes in an NSE script. It would look like this:
>        nmap -6 --script=ipv6-multicast --script-args=newtargets
> The ipv6-multicast.nse script would send all the multicast probes we
> know of, and wait for replies. It would then add them to the Nmap
> scanning queue with the target.add function:
>        http://nmap.org/nsedoc/lib/target.html#add
> This way we can make progress on multicast discovery without needing all
> the details of figuring out when to do multicast versus unicast. Who
> knows, maybe NSE is the best way to implement this anyway.
>
> David Fifield



-- 
Regards
Xu Weilin 许伟林
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