dhcpcd-discuss

Hi

On 29/04/2018 21:04, stephane@xxxxxxxxxxxxx wrote:
> Hello all.
>
> In order to make my dhcp6 requests work, I have to make a specific
> request where 80 % of options are useless, but it's what it takes to
> get my ISP's routers to let them through.
>
> I particularly have to have options sol_max_rt, inf_max_rt, then 94,
> 95 and 96 (which are S64 map-e, map-t and 4over6).
>
> I wonder how I can make those three last options.
>
> Notice also that I am ok, if need be, to be tester. (I just have no
> clue about how to program a dhcp client, ipv4 or 6).

I just looked up rfc7598 for option 94 and it went woosh over my head.
My understanding is that the DHCP client just requests these options in 
the ORO. dhcpcd can then decode the contents for option use via a hook 
script.

Attached is a patch to allow this.
You should be able to add this to dhcpcd.conf

# SOL_MAX and INF_MAX should already be requested by default
option dhcp6_sol_max_rt, dhcp6_inf_max_rt
# Request 94, 95 and 96
option dhcp6_s46_cont_mape, dhcp6_s46_cont_mapt, dhcp6_s46_cont_lw

You should then see the options appear as variables for use in 
dhcpcd-run-hooks(8). However, I have no means of testing this. dhcpcd 
cannot fully decode option 92 due to the options appearing AFTER a 
variable length part. I have no interest in even attempting to fix this 
as you've not noted it as a requirement.

Let me know how it works out for you!

Roy

diff --git a/src/dhcpcd-definitions.conf b/src/dhcpcd-definitions.conf
index f8117d27..625f8607 100644
--- a/src/dhcpcd-definitions.conf
+++ b/src/dhcpcd-definitions.conf
@@ -579,6 +579,37 @@ define6 80	ip6address		link_address
 define6 82	request uint32		sol_max_rt
 define6	83	request uint32		inf_max_rt
 
+# DHCPv6 Softwire Address and Port-Mapped Clients
+define6	89	embed			s46_rule
+embed		binflags=0000000F	flags
+embed		byte			ea_len
+embed		byte			prefix4_len
+embed		ipaddress		ipv4_prefix
+embed		ip6address		ipv6_prefix
+define6	90	ip6address		s64_br
+define6	91	embed			s46_dmr
+embed		byte			prefix_len
+embed		binhex			prefix
+define6	92	embed			s46_v4v6bind
+embed		ipaddress		ipv4_address
+embed		byte			ipv6_prefix_len
+embed		binhex			ipv6_prefix_and_options
+# Cannot decode options after variable length address ...
+#encap	93	option
+define6	93	embed			s46_portparams
+embed		byte			offset
+embed		byte			psid_len
+embed		uint16			psid
+define6	94	embed			s46_cont_mape
+encap	89	option
+encap	90	option
+define6	95	embed			s46_cont_mapt
+encap	89	option
+encap	91	option
+define6	96	embed			s46_cont_lw
+encap	90	option
+encap	92	option
+
 # DHCPv6 Address Selection Policy
 # Currently not supported