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Date:   Thu, 14 Oct 2021 23:36:27 +0200
From:   Dmytro Shytyi <dmytro@shytyi.net>
To:     "Erik Kline" <ek@google.com>
Cc:     "Jakub Kicinski" <kuba@kernel.org>,
        "yoshfuji" <yoshfuji@linux-ipv6.org>,
        "kuznet" <kuznet@ms2.inr.ac.ru>,
        "liuhangbin" <liuhangbin@gmail.com>, "davem" <davem@davemloft.net>,
        "netdev" <netdev@vger.kernel.org>,
        "linux-kernel" <linux-kernel@vger.kernel.org>,
        "Jscherpelz" <jscherpelz@google.com>
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Subject: Re: [PATCH net-next V10] net: Variable SLAAC: SLAAC with prefixes
 of arbitrary length in PIO
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 > > This patch solves "Race to the bottom"  problem  in  VSLAAC. 
 >  
 > How exactly does this "solve" the fundamental problem? 
 > 

VSLAAC is replaced by the SLAAC starting from /64 
 
if (pinfo->prefix_len == 64) {
64_bit_addr_gen
} else if (pinfo->prefix_len > 0 && pinfo->prefix_len < 64 &&
              in6_dev->cnf.variable_slaac) {
variable_bit_addr_gen
 } else {
             net_dbg_ratelimited("IPv6: Prefix with unexpected length %d\n",
                                            pinfo->prefix_len);
 }

I meant to say that this is no longer an issue in VSLAAC particular context, considering /128 bits the "bottom".
In this version of the patch, we are not reaching the /128 bit "bottom".

Best regards,
Dmytro SHYTYI.