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soc:2011:pcmattman:journal:week8 [2011/07/16 04:18]
pcmattman day 6 log
soc:2011:pcmattman:journal:week8 [2011/07/16 22:45]
pcmattman day 7 log
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 I still need to implement some way for DHCPv6 to get enough information out of a router solicitation to make an address assignment globally routable, but that won't take too long at all. I think I can even do it without having to change too much of the existing router solicit code. I still need to implement some way for DHCPv6 to get enough information out of a router solicitation to make an address assignment globally routable, but that won't take too long at all. I think I can even do it without having to change too much of the existing router solicit code.
 +
 +**Update (0039 UTC):**
 +
 +I've managed to fix some routing issues in IPv6 and rework router solicitations as needed to allow DHCPv6 to get information about the routers and prefixes available. This means DHCPv6 can now assign a fully routable address, rather than having to assume the address is a /128 or something.
 +
 +This means DHCPv6 is essentially "​complete"​ in the sense that it can be used as a complete alternative to SLAAC. It does not yet have any features related to network booting, nor does it have features that gPXE's DHCPv4 implementation has such as caching.
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 +I just need to merge and rebase the commits related to DHCPv6 and rename and reimplement the "​ipv6"​ command now that this is complete. The complete user-visible IPv6 interface is now essentially complete; the remainder of my project is backend work.
 +
 +==== Day 7 (July 17) ====
 +
 +I **FINALLY** implemented time out handling for router solicitations today, which means gPXE won't hang anymore if a router advertisement daemon isn't available on the network. This let me try out DHCPv6 without any router advertisements - and it worked as expected. It assigned a /128 address, which was not able to be routed.
 +
 +I also fixed some interesting bugs from the past couple of days in the DHCPv6 code and updated the NDP router solicit code a bit to send a source link-local address with router advertisements (which helps the router avoid sending a neighbour solicit). I also managed to find a bug in the NDP code where the layout of "​struct router_advert"​ was incorrect, causing the flags such as OTHERCONF and MANAGED to never be seen. This was fortunately easy to resolve, and now gPXE can ask for only DNS information on a network where router advertisements are used for autoconfiguration (ie, mine! :) ).
 +
 +During my testing I have noticed that there are a few issues with the neighbour solicit/​advertisement code, which I will be looking at soon. The biggest issue so far is that processing of neighbour advertisements makes some rather significant assumptions about the layout of the incoming packet. I'd like to change that to parse the options in the packet and handle each as necessary.
 +
 +I also made some ip6mgmt.c changes today. These basically mean DHCPv6 only gets used in environments where router advertisements are not available, or where router advertisements suggest using a DHCPv6 server for additional configuration. I think this command is well and truly ready to be renamed from "​ipv6"​ to something more like "​ipv6-enable"​ or something, but I'm not sure exactly what to name it.

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