From: Pablo Neira Ayuso <firstname.lastname@example.org>
To: Kevin 'ldir' Darbyshire-Bryant <email@example.com>
Cc: "firstname.lastname@example.org" <email@example.com>
Subject: Re: [PATCH 1/1] netfilter: connmark: introduce savedscp
Date: Tue, 9 Apr 2019 00:39:00 +0200 [thread overview]
Message-ID: <20190408223900.jizstw6bhjwt2w63@salvia> (raw)
On Sun, Mar 24, 2019 at 02:23:45PM +0000, Kevin 'ldir' Darbyshire-Bryant wrote:
> savedscp is a method of storing the DSCP of an ip packet into conntrack
> mark. In combination with a suitable tc filter action (conndscp but may
> end up being integrated into connmark) DSCP values are able to be stored
> on egress and restored on ingress across links that otherwise alter or
> bleach DSCP.
> This is useful for qdiscs such as CAKE which are able to shape according
> to policies based on DSCP.
> Ingress classification is traditionally a challenging task since
> iptables rules haven't yet run and tc filter/eBPF programs are pre-NAT
> lookups, hence are unable to see internal IPv4 addresses as used on the
> typical home masquerading gateway.
> The ingress problem is solved by the tc filter, but the tc people didn't
> like the idea of tc setting conntrack mark values, though they are ok
> with reading conntrack values and hence restoring DSCP from conntrack
> x_tables CONNMARK with the new savedscp action solves the problem of
> storing the DSCP to the conntrack mark.
> It accepts 2 parameters. The mark is a 32bit value with usually one
> bit set. This bit is set when savedscp saves the DSCP to the mark.
> This is useful to implement a 'one shot'
> iptables based classification where the 'complicated' iptables rules are
> only run once to classify the connection on initial (egress) packet and
> subsequent packets are all marked/restored with the same DSCP. A mark
> of zero disables the setting of a status bit/s.
> The mask is a 32bit value of at least 6 contiguous bits and represents
> the area where the DSCP will be stored.
> iptables -A QOS_MARK_eth0 -t mangle -j CONNMARK --savedscp-mark 0x01000000/0xfc000000
> Would store the DSCP in the top 6 bits of the 32bit mark field, and use
> the LSB of the top byte as the 'DSCP has been stored' marker.
I'd prefer we explore how to express this in nftables, I think the
main problem here is that we do not support for datatype compatibility
/ casting yet, hence dscp cannot be assign to the mark. But we only
need to update userspace code to achieve this.
next prev parent reply other threads:[~2019-04-08 22:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-24 14:23 [RFC PATCH 0/1] netfilter: xt_connmark: add savedscp-mark action Kevin 'ldir' Darbyshire-Bryant
2019-03-24 14:23 ` [PATCH 1/1] netfilter: connmark: introduce savedscp Kevin 'ldir' Darbyshire-Bryant
2019-04-08 22:39 ` Pablo Neira Ayuso [this message]
2019-04-08 23:16 ` Kevin 'ldir' Darbyshire-Bryant
2019-04-09 14:23 ` [RFC nf-next v2 0/2] xt_connmark: add savedscp-mark action Kevin 'ldir' Darbyshire-Bryant
2019-04-09 14:23 ` [RFC nf-next v2 1/2] netfilter: connmark: introduce savedscp Kevin 'ldir' Darbyshire-Bryant
2019-04-30 12:29 ` Pablo Neira Ayuso
2019-04-30 20:40 ` Kevin 'ldir' Darbyshire-Bryant
2019-04-09 14:23 ` [RFC nf-next 2/2] iptables: connmark - add savedscp option Kevin 'ldir' Darbyshire-Bryant
2019-12-03 16:06 ` [PATCH 0/1] netfilter: connmark: introduce set-dscpmark Kevin Darbyshire-Bryant
2019-12-03 16:06 ` [PATCH 1/1] " Kevin Darbyshire-Bryant
2019-12-09 23:57 ` Kevin 'ldir' Darbyshire-Bryant
2019-12-05 8:56 ` [PATCH 0/1] " Jeremy Sowden
2019-12-05 9:46 ` Kevin 'ldir' Darbyshire-Bryant
2019-12-06 8:54 ` Jeremy Sowden
2019-12-05 10:49 ` Florian Westphal
2019-12-05 22:00 ` Jeremy Sowden
2019-12-09 21:42 ` [RFC PATCH nf-next] netfilter: conntrack: add support for storing DiffServ code-point as CT mark Jeremy Sowden
2019-12-09 21:42 ` [RFC PATCH nftables] Add "ct dscpmark" conntrack statement Jeremy Sowden
2019-12-09 22:47 ` [RFC PATCH nf-next] netfilter: conntrack: add support for storing DiffServ code-point as CT mark Florian Westphal
2019-12-09 23:23 ` Jeremy Sowden
2019-12-10 1:25 ` Florian Westphal
2019-12-10 11:01 ` Jeremy Sowden
2019-12-10 11:32 ` Florian Westphal
2019-12-10 19:52 ` Jeremy Sowden
2019-12-11 13:01 ` [PATCH nf-next v2] netfilter: connmark: introduce set-dscpmark Kevin Darbyshire-Bryant
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