openwrt/target/linux
Kevin Darbyshire-Bryant dba5a01358 kernel: netfilter add connmark savedscp support
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
marks.

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 1
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.

e.g.

iptables -A QOS_MARK_eth0 -t mangle -j CONNMARK --savedscp-mark 0xfc000000/0x01000000

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.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
2019-07-25 10:20:59 +01:00
..
apm821xx treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
ar7
ar71xx ar71xx: fix WLAN LED names for Archer C7 2019-07-25 07:48:10 +02:00
arc770
archs38
armvirt
at91
ath25
ath79 ath79: fix indent in 01_leds 2019-07-24 20:36:27 +02:00
bcm53xx
brcm47xx brcm47xx: fix 831-old_gpio_wdt.patch for linux 4.19 2019-07-17 22:59:29 +02:00
brcm63xx
brcm2708 brcm2708: Add Raspberry Pi 4 support 2019-07-14 12:44:14 +02:00
cns3xxx treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
gemini treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
generic kernel: netfilter add connmark savedscp support 2019-07-25 10:20:59 +01:00
imx6 imx6: apalis: add missing jffs2reset to ramfs during sysupgrade 2019-07-17 12:16:29 +02:00
ipq40xx treewide: sysupgrade: get rid of platform_nand_pre_upgrade() 2019-07-22 14:27:37 +02:00
ipq806x treewide: sysupgrade: get rid of platform_nand_pre_upgrade() 2019-07-22 14:27:37 +02:00
ixp4xx treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
kirkwood treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
lantiq treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
layerscape layerscape: sysupgrade: get rid of platform_pre_upgrade() 2019-07-22 14:27:37 +02:00
malta
mediatek treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
mpc85xx treewide: sysupgrade: don't use $ARGV in platform_do_upgrade() 2019-07-17 08:05:38 +02:00
mvebu mvebu: sysupgrade: don't use $ARGV in platform_check_image() 2019-07-17 08:09:41 +02:00
mxs
octeon
octeontx
omap
orion orion: sysupgrade: change platform_check_image() args validation 2019-07-16 13:58:26 +02:00
oxnas
pistachio treewide: sysupgrade: get rid of platform_nand_pre_upgrade() 2019-07-22 14:27:37 +02:00
ramips ramips: enable Newifi D1 SD slot 2019-07-23 13:14:07 +08:00
rb532 treewide: sysupgrade: get rid of platform_nand_pre_upgrade() 2019-07-22 14:27:37 +02:00
samsung
sunxi
tegra tegra: split up DEVICE_TITLE 2019-07-15 19:28:55 +02:00
uml
x86 x86: add modern network modules to Generic target 2019-07-17 12:16:29 +02:00
zynq
Makefile