netdev - Re: [BUG / question] in routing rules, some options (e.g. ipproto, sport) cause rules to be ignored in presence of packet marks

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Date:   Fri, 9 Apr 2021 15:02:41 +0200
From:   Florian Westphal <fw@...len.de>
To:     Michal Soltys <msoltyspl@...dex.pl>
Cc:     Ido Schimmel <idosch@...sch.org>,
        Linux Netdev List <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>
Subject: Re: [BUG / question] in routing rules, some options (e.g. ipproto,
 sport) cause rules to be ignored in presence of packet marks

Michal Soltys <msoltyspl@...dex.pl> wrote:
> On 3/29/21 10:52 PM, Ido Schimmel wrote:
> > 
> > ip_route_me_harder() does not set source / destination port in the
> > flow key, so it explains why fib rules that use them are not hit after
> > mangling the packet. These keys were added in 4.17, but I
> > don't think this use case every worked. You have a different experience?
> > 
> 
> So all the more recent additions to routing rules - src port, dst port, uid
> range and ipproto - are not functioning correctly with the second routing
> check.
>
> Are there plans to eventually fix that ?
> 
> While I just adjusted/rearranged my stuff to not rely on those, it should
> probably be at least documented otherwise (presumably in ip-rule manpage and
> perhaps in `ip rule help` as well).

Fixing this would be better. As Ido implies it should be enough to fully
populate the flow keys in ip(6)_route_me_harder.