Re: [PATCH 2/4] lwip: clean up IPv6 address handling in init_ifs and inquire_device

From: Samuel Thibault <[email protected]>
To: "Joan Lledó"<[email protected]>
Cc: <[email protected]>, <[email protected]>, <[email protected]>, "Joan Lledó"<[email protected]>
Date: Sat, 27 Jun 2026 23:15:01 +0100
Subject: Re: [PATCH 2/4] lwip: clean up IPv6 address handling in init_ifs and inquire_device
 >  
 > >     - and set prefix_len based on whether the 
 > >       address is static (64) or autoconf (128) instead of always 64. 
 >  
 > ? 
 >  
 > Even autoconf addresses usually do have a non-128 prefix len, to be able 
 > to reach neighbours. 

I agree with Samuel. Please don't do this.

Router Advertisements advertise a Prefix from which an address *may* be derived based on length (64) and flags (make an autoconf address).

DHCPv6 addresses are always /128 because they are not directly tied to a Prefix.

It is impossible to infer a Prefix Length from any address.

Roy