[FS#4261] [odhcp6c] Add an option to discard stateless advertisements

OpenWrt Bugs openwrt-bugs at lists.openwrt.org
Tue Feb 8 01:50:04 PST 2022


A new Flyspray task has been opened.  Details are below. 

User who did this - viktor-iarmola (viktor-iarmola) 

Attached to Project - OpenWrt/LEDE Project
Summary - [odhcp6c] Add an option to discard stateless advertisements
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - When odhcp6c runs in `unknown` mode (`-N try` as default and `-P x` without `-F`) it tries to determine its actual mode from received advertisements. 

Normally, when there are both stateful (with IA_NA or IA_PD) and stateless (without both IA_NA and IA_PD) advertisements in the network - it works fine because odhcp6c prefers stateful ones and prioritizes them higher. However, some setups in the wild interfere with this scenario via either of:
  * stateful and stateless advertisements come with the same server DUID - in that case if stateless advertisement comes last we will go into stateless mode despite there being stateful advertisements available;
  * stateful advertisements are "late" and `odhcp6c` only receives stateless ones during its first solicit session.

Both of these cases could seemingly be avoided by `-N force` and/or `-F` options, which will force `odhcp6c` to run in "stateful" mode and ignore advertisements not carrying specific option. However, it is currently impossible to express the intention of wishing to accept only advertisements carrying //either// IA_NA or IA_PD or both of them - and ignoring advertisement without both IA_NA and IA_PD.

To solve this a pull request was created to support a new option for `odhcp6c` - `-D` to discard stateless advertisements. 
Please take a look at the github PR with some extra details: https://github.com/openwrt/odhcp6c/pull/69

More information can be found at the following URL:

You are receiving this message because you have requested it from the Flyspray bugtracking system.  If you did not expect this message or don't want to receive mails in future, you can change your notification settings at the URL shown above.

More information about the openwrt-bugs mailing list