[Dnsmasq-discuss] RFC: allowing arbitrarily long options

[Simon Kelley]

I'm in favour, in theory at least, of removing arbitrary limits.
Experience has shown that no matter how big, someone, somewhere, will
always find them. The code originally used a fixed buffer which happened
to be unused at that point, to reduce the memory footprint. Whilst
dnsmasq is still intended to be "small", small is a relative thing, and
absolutely, rather bigger than it was 15 years ago, so allocating a big
enough buffer is fine.

In this case, though, as you hint, it's likely that shell limits will
also be a problem. Even eliminating that by using configuration files,
you still have very long lines, which is ugly.

Can't we solve this problem by allowing repeated interface names, so

--bridge-interface=eth1,alias-1,alias-2

becomes identical to

--bridge-interface=eth1,alias-1
--bridge-interface=eth1,alias-2

the patch to implement that is probably smaller than your offering.


Maybe we should do both?


Cheers,

Simon.








On 07/01/18 14:25, Neil Jerram wrote:
> Calico [1] with OpenStack
> (https://docs.projectcalico.org/v2.6/getting-started/openstack/) uses
> dnsmasq with a very long --bridge-interface option:
> 
> --bridge-interface=<context-if-name>,<alias-if-name>,<alias-if-name>,...,
> 
> where each occurrence of ",<alias-if-name>" occupies 15 characters, and
> there can in principle be as many <alias-if-name>s as you can have VMs
> on a single OpenStack compute host.  Currently an option arg is limited
> in dnsmasq to 1025 chars overall, which only allows for 67
> <alias-if-name>s, which is not necessarily enough, on a powerful compute
> host.
> 
> So I wonder what folk would think about reallocating as necessary to
> allow an option arg to be arbitrarily long?  (Or at least, as long as
> getopt and the containing shell will allow.)  For reference I've
> attached a patch that I think would implement that - but I haven't yet
> been able to test it at all, so please don't merge it yet!
> 
> Thanks in advance for your thoughts!
>       Neil
> 
> 
> 
> _______________________________________________
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss at lists.thekelleys.org.uk
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
> 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/attachments/20180113/da504342/attachment.sig>