Hi Tomek,
On Wed, Jul 13, 2016 at 11:20 AM, Tomek Mrugalski < [email protected]> wrote: > Hi! > > Long time user, first time trying to extend the code and would like to > ask for a bit of guidance. I'm trying to extend DHCPv6 (packet-dhcpv6.c) > dissector to support RFC7598. Couple options in that RFC uses new option > format that stores IPv6 prefix as two fields: > > 1. prefix-len (1 octet, specifies length in bits) > 2. prefix (minimum number of octets necessary to store the most > significant bits) > > The prefix field can be of any length between 1 and 16. > > This is the recommended way for new options (see RFC7227, Section 5.3), > so we will see more of this formatting in the future. > > For specific example, see S46 DMR option here: > https://tools.ietf.org/html/rfc7598#section-4.3 > > How can I parse and display this in wireshark? > I'd like to display it as human readable prefix, e.g. 2001:db8::/32. I > could create a separate 16 bytes long buffer, then copy first > (prefix-len) bytes and pad them with zeros, but I don't know how to > > Do you have look icmpv6.c dissector ? if i remember there is the same case for add prefix (like /XX), you can use proto_item_append_text(ti, "/%u", prefix_len); for example > So far I came up with the following code: http://pastebin.com/wsFPF4Kp > (see lines 1987 to 1999). It sorta works, but displays prefix len as > separate field and part of the prefix as hex. Although that matches > on-wire format, that's not really user friendly way. > > I've made the traffic capture available in case it is useful: > http://git.kea.isc.org/~tomek/lw4over6/dhcpv6-lw4over6-rfc7598.pcapng > See packet 6 or 8. > Can you push directly on Gerrit ( https://code.wireshark.org/review (you can set WIP on commit log), it is more easy for review and try... and push also the pcap on BugTracker ( https://bugs.wireshark.org ) > > Not sure if it changes anything, but I'm more than willing to contribute > the code once it's functional. Finally, there's a bunch > of DHCPv6 options that were published, but are not supported yet. Do you > prefer to get them all in one patch or should I split them up into > separate patches? > If it is options from the same RFC, you can push only a patch with all options. Cheers, > > Thanks in advance, > Tomek > > ___________________________________________________________________________ > Sent via: Wireshark-dev mailing list <[email protected]> > Archives: https://www.wireshark.org/lists/wireshark-dev > Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev > mailto:[email protected] > ?subject=unsubscribe >
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