On 21/01/2020 23:31, Harald Jensås wrote: > On Tue, 2020-01-21 at 23:38 +0100, Tore Anderson wrote: >> * Simon Kelley >> >>> I have an alternative suggestion for the syntax of dhcp-host. >>> It's less flexible, but simpler and easier to understand and to >>> explain, >>> and uses existing semantics rather than adding new keywords. >>> >>> The idea is just to add a prefix-length to the address. That allows >>> you >>> to define (eg) 1,2,4,8, or 16 addresses for use by a host simply >>> and >>> easily in a way which makes it difficult to accidentally overlap >>> address >>> ranges, and is fairly obvious to anyone who has done done any IPv6 >>> network configuration. >>> >>> for instance to reserve four addresses for each host we cold do: >>> >>> dhcp-host=00:11:22:33:44:55,[fd12:3456::aa00/62] >>> dhcp-host=00:11:22:33:44:56,[fd12:3456::aa04/62] >>> dhcp-host=00:11:22:33:44:57,[fd12:3456::aa08/62] >>> >>> As a sanity check, if the "host part" of the address isn't zero, >>> >>> ie [fd12:3456::aa01/62] >>> >>> that could be rejected with an error. >> > > I like the idea of using a prefix. I have a new revision of the patch > with this implemented at the bottom of this e-mail. It's far better and > more flexible than the keywords approach I came up with initially, as > it's now possible to mix individual addreses, prefixed ranges and > prefixed wildcard addresses etc. > > # A list of addressses > dhcp-host=52:54:00:3f:5c:c0,[fd12:3456:789a:1::aa02][fd12:3456:789a:1::aa04][fd12:3456:789a:1::aa06],host1 > > # Mixing a prefix and a single address > dhcp-host=52:54:00:3f:5c:c0,[fd12:3456:789a:1::aa04/62][fd12:3456:789a:1::aa00],host1 > > # Prefixed wildcard > dhcp-host=52:54:00:3f:5c:c0,[::aa04/62],host1 > > >> I have done quite a bit of IPv6 networking, but the use of /62 here >> is anything but «fairly obvious» to me. >> >> It would have been much more intuitive to use /126, in my opinion. >> >> Tore >> > > I too found it a bit curios with /62 at first, as I understand it the > interface identifier is always the 64 least significant bit's in IPv6 > ref[1]. > > I think changing the patch to use the full 128 bit's as a mask is > trivial. We may also support both by subtracting 64 from any prefix > larger than 64 in the code? So /126 and /62 yield the same result. > > What does other people think? >
/62 is crazy, I don't know why I even said that. Harald, if you could tweak your patch work with 128-based prefixes, I think we have reached a successful conclusion. Simon. _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss