Re: [PATCH] net-ipv6: changes to ->tclass (via IPV6_TCLASS) should sk_dst_reset()

On Tue, 23 Nov 2021 14:32:08 -0800 Maciej Żenczykowski wrote:

From: Maciej Żenczykowski <redacted>

This is to match ipv4 behaviour, see __ip_sock_set_tos()
implementation.

Technically for ipv6 this might not be required because normally we
do not allow tclass to influence routing, yet the cli tooling does
support it:

lpk11:~# ip -6 rule add pref 5 tos 45 lookup 5
lpk11:~# ip -6 rule
5:      from all tos 0x45 lookup 5

and in general dscp/tclass based routing does make sense.

We already have cases where dscp can affect vlan priority and/or
transmit queue (especially on wifi).

So let's just make things match.  Easier to reason about and no harm.

Cc: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Maciej Żenczykowski <redacted>

Please send related patches as a series. There are dependencies here
which prevent the build bot from doing its job (plus it's less work 
for me since I apply by series :)).