kernel: connmark set-dscpmark follow upstreamimg attempt

I'm having another attempt at trying to getting the 'store dscp into
conntrack connmark' functionality into upstream kernel, since the
restore function (act_ctinfo) has been accepted.

The syntax has changed from 'savedscp' to 'set-dscpmark' since that
conforms more closely with existing functionality.

4.14 backport is more of a hack since the structure versioning
mechanism isn't in place.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
This commit is contained in:
Kevin Darbyshire-Bryant 2019-12-03 14:00:05 +00:00
parent e481df07fa
commit a1cfe0dcbb
3 changed files with 266 additions and 160 deletions

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@ -1,100 +0,0 @@
From 5a4d7714faa28c03e85d696fba82716fbda5c432 Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Date: Sat, 23 Mar 2019 09:29:49 +0000
Subject: [PATCH] netfilter: connmark: introduce savedscp
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>
---
include/uapi/linux/netfilter/xt_connmark.h | 3 ++-
net/netfilter/xt_connmark.c | 21 ++++++++++++++++++++-
2 files changed, 22 insertions(+), 2 deletions(-)
--- a/include/uapi/linux/netfilter/xt_connmark.h
+++ b/include/uapi/linux/netfilter/xt_connmark.h
@@ -16,7 +16,8 @@
enum {
XT_CONNMARK_SET = 0,
XT_CONNMARK_SAVE,
- XT_CONNMARK_RESTORE
+ XT_CONNMARK_RESTORE,
+ XT_CONNMARK_SAVEDSCP
};
struct xt_connmark_tginfo1 {
--- a/net/netfilter/xt_connmark.c
+++ b/net/netfilter/xt_connmark.c
@@ -42,6 +42,7 @@ connmark_tg(struct sk_buff *skb, const s
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u_int32_t newmark;
+ u_int8_t dscp, maskshift;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
@@ -57,7 +58,25 @@ connmark_tg(struct sk_buff *skb, const s
break;
case XT_CONNMARK_SAVE:
newmark = (ct->mark & ~info->ctmask) ^
- (skb->mark & info->nfmask);
+ (skb->mark & info->nfmask);
+ if (ct->mark != newmark) {
+ ct->mark = newmark;
+ nf_conntrack_event_cache(IPCT_MARK, ct);
+ }
+ break;
+ case XT_CONNMARK_SAVEDSCP:
+ if (skb->protocol == htons(ETH_P_IP))
+ dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
+ else /* protocol doesn't have diffserv */
+ break;
+
+ /* nfmask contains the mask shift value */
+ maskshift = info->nfmask & 0x1f;
+ newmark = (ct->mark & ~info->ctmark) |
+ (info->ctmask | (dscp << maskshift));
+
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, ct);

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@ -1,12 +1,12 @@
From f171924dcf1d0b31fb7bd1cff113d7a1f7f05ec2 Mon Sep 17 00:00:00 2001
From f1627abea333781d3e2a61bac4c7fd4502395741 Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Date: Sat, 23 Mar 2019 09:29:49 +0000
Subject: [PATCH] netfilter: connmark: introduce savedscp
Subject: [PATCH] netfilter: connmark: introduce set-dscpmark
savedscp is a method of storing the DSCP of an ip packet into conntrack
mark. In combination with a suitable tc filter action (act_ctinfo) DSCP
values are able to be stored in the mark on egress and restored on
ingress across links that otherwise alter or bleach DSCP.
set-dscpmark is a method of storing the DSCP of an ip packet into
conntrack mark. In combination with a suitable tc filter action
(act_ctinfo) DSCP values are able to be stored in the mark 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.
@ -16,12 +16,12 @@ 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.
x_tables CONNMARK savedscp action solves the problem of storing the DSCP
to the conntrack mark in a way suitable for the new act_ctinfo tc action
to restore.
x_tables CONNMARK set-dscpmark target solves the problem of storing the
DSCP to the conntrack mark in a way suitable for the new act_ctinfo tc
action to restore.
The savedsp option accepts 2 parameters, a 32bit 'dscpmask' and a 32bit
'statemask'. The dscp mask must be a minimum of 6 contiguous bits and
The set-dscpmark option accepts 2 parameters, a 32bit 'dscpmask' and a
32bit 'statemask'. The dscp mask must be 6 contiguous bits and
represents the area where the DSCP will be stored in the connmark. The
state mask is a minimum 1 bit length mask that must not overlap with the
dscpmask. It represents a flag which is set when the DSCP has been
@ -33,7 +33,7 @@ mask of zero disables the setting of a status bit/s.
example syntax with a suitably modified iptables user space application:
iptables -A QOS_MARK_eth0 -t mangle -j CONNMARK --savedscp-mark 0xfc000000/0x01000000
iptables -A QOS_MARK_eth0 -t mangle -j CONNMARK --set-dscpmark 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.
@ -55,7 +55,7 @@ an identically configured tc action to restore looks like:
tc filter show dev eth0 ingress
filter parent ffff: protocol all pref 10 u32 chain 0
filter parent ffff: protocol all pref 10 u32 chain 0 fh 800: ht divisor 1
filter parent ffff: protocol all pref 10 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1 not_in_hw
filter parent ffff: protocol all pref 10 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1: not_in_hw
match 00000000/00000000 at 0
action order 1: ctinfo zone 0 pipe
index 2 ref 1 bind 1 dscp 0xfc000000/0x1000000
@ -77,37 +77,29 @@ filter parent ffff: protocol all pref 10 u32 chain 0 fh 800::800 order 2048 key
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
---
include/uapi/linux/netfilter/xt_connmark.h | 3 ++-
net/netfilter/xt_connmark.c | 17 +++++++++++++++++
2 files changed, 19 insertions(+), 1 deletion(-)
net/netfilter/xt_connmark.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
--- a/include/uapi/linux/netfilter/xt_connmark.h
+++ b/include/uapi/linux/netfilter/xt_connmark.h
@@ -16,7 +16,8 @@
enum {
XT_CONNMARK_SET = 0,
XT_CONNMARK_SAVE,
- XT_CONNMARK_RESTORE
+ XT_CONNMARK_RESTORE,
+ XT_CONNMARK_SAVEDSCP
};
enum {
diff --git a/net/netfilter/xt_connmark.c b/net/netfilter/xt_connmark.c
index ec377cc6a369..823d925b3aaf 100644
--- a/net/netfilter/xt_connmark.c
+++ b/net/netfilter/xt_connmark.c
@@ -42,6 +42,7 @@ connmark_tg_shift(struct sk_buff *skb, c
u_int32_t new_targetmark;
@@ -42,6 +42,7 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u_int32_t newmark;
+ u_int8_t dscp;
+ u_int8_t dscp, maskshift;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
@@ -74,6 +75,21 @@ connmark_tg_shift(struct sk_buff *skb, c
nf_conntrack_event_cache(IPCT_MARK, ct);
}
break;
+ case XT_CONNMARK_SAVEDSCP:
@@ -49,7 +50,21 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
switch (info->mode) {
case XT_CONNMARK_SET:
- newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
+ if (info->nfmask & 0x80000000) {
+ newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
+ } else {
+ if (skb->protocol == htons(ETH_P_IP))
+ dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
+ else if (skb->protocol == htons(ETH_P_IPV6))
@ -115,21 +107,23 @@ Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+ else /* protocol doesn't have diffserv */
+ break;
+
+ /* nfmask contains the mask shift value */
+ maskshift = info->nfmask & 0x1f;
+ newmark = (ct->mark & ~info->ctmark) |
+ (info->ctmask | (dscp << info->shift_bits));
+ if (ct->mark != newmark) {
+ ct->mark = newmark;
+ nf_conntrack_event_cache(IPCT_MARK, ct);
+ (info->ctmask | (dscp << maskshift));
+ }
+ break;
case XT_CONNMARK_RESTORE:
new_targetmark = (ct->mark & info->ctmask);
if (info->shift_dir == D_SHIFT_RIGHT)
@@ -86,6 +102,7 @@ connmark_tg_shift(struct sk_buff *skb, c
skb->mark = newmark;
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, ct);
@@ -57,7 +72,7 @@ connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
break;
}
+out:
return XT_CONTINUE;
}
case XT_CONNMARK_SAVE:
newmark = (ct->mark & ~info->ctmask) ^
- (skb->mark & info->nfmask);
+ (skb->mark & info->nfmask);
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, ct);
--
2.21.0 (Apple Git-122.2)

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@ -0,0 +1,212 @@
From eda40b8c8c82e0f2789d6bc8bf63846dce2e8f32 Mon Sep 17 00:00:00 2001
From: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Date: Sat, 23 Mar 2019 09:29:49 +0000
Subject: [PATCH] netfilter: connmark: introduce set-dscpmark
set-dscpmark is a method of storing the DSCP of an ip packet into
conntrack mark. In combination with a suitable tc filter action
(act_ctinfo) DSCP values are able to be stored in the mark 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.
x_tables CONNMARK set-dscpmark target solves the problem of storing the
DSCP to the conntrack mark in a way suitable for the new act_ctinfo tc
action to restore.
The set-dscpmark option accepts 2 parameters, a 32bit 'dscpmask' and a
32bit 'statemask'. The dscp mask must be 6 contiguous bits and
represents the area where the DSCP will be stored in the connmark. The
state mask is a minimum 1 bit length mask that must not overlap with the
dscpmask. It represents a flag which is set when the DSCP has been
stored in the conntrack 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 state
mask of zero disables the setting of a status bit/s.
example syntax with a suitably modified iptables user space application:
iptables -A QOS_MARK_eth0 -t mangle -j CONNMARK --set-dscpmark 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.
|----0xFC----conntrack mark----000000---|
| Bits 31-26 | bit 25 | bit24 |~~~ Bit 0|
| DSCP | unused | flag |unused |
|-----------------------0x01---000000---|
^ ^
| |
---| Conditional flag
| set this when dscp
|-ip diffserv-| stored in mark
| 6 bits |
|-------------|
an identically configured tc action to restore looks like:
tc filter show dev eth0 ingress
filter parent ffff: protocol all pref 10 u32 chain 0
filter parent ffff: protocol all pref 10 u32 chain 0 fh 800: ht divisor 1
filter parent ffff: protocol all pref 10 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1: not_in_hw
match 00000000/00000000 at 0
action order 1: ctinfo zone 0 pipe
index 2 ref 1 bind 1 dscp 0xfc000000/0x1000000
action order 2: mirred (Egress Redirect to device ifb4eth0) stolen
index 1 ref 1 bind 1
|----0xFC----conntrack mark----000000---|
| Bits 31-26 | bit 25 | bit24 |~~~ Bit 0|
| DSCP | unused | flag |unused |
|-----------------------0x01---000000---|
| |
| |
---| Conditional flag
v only restore if set
|-ip diffserv-|
| 6 bits |
|-------------|
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
---
include/uapi/linux/netfilter/xt_connmark.h | 10 ++++
net/netfilter/xt_connmark.c | 55 ++++++++++++++++++----
2 files changed, 57 insertions(+), 8 deletions(-)
--- a/include/uapi/linux/netfilter/xt_connmark.h
+++ b/include/uapi/linux/netfilter/xt_connmark.h
@@ -20,6 +20,11 @@ enum {
};
enum {
+ XT_CONNMARK_VALUE = BIT(0),
+ XT_CONNMARK_DSCP = BIT(1)
+};
+
+enum {
D_SHIFT_LEFT = 0,
D_SHIFT_RIGHT,
};
@@ -34,6 +39,11 @@ struct xt_connmark_tginfo2 {
__u8 shift_dir, shift_bits, mode;
};
+struct xt_connmark_tginfo3 {
+ __u32 ctmark, ctmask, nfmask;
+ __u8 shift_dir, shift_bits, mode, func;
+};
+
struct xt_connmark_mtinfo1 {
__u32 mark, mask;
__u8 invert;
--- a/net/netfilter/xt_connmark.c
+++ b/net/netfilter/xt_connmark.c
@@ -36,12 +36,13 @@ MODULE_ALIAS("ipt_connmark");
MODULE_ALIAS("ip6t_connmark");
static unsigned int
-connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info)
+connmark_tg_shift(struct sk_buff *skb, const struct xt_connmark_tginfo3 *info)
{
enum ip_conntrack_info ctinfo;
u_int32_t new_targetmark;
struct nf_conn *ct;
u_int32_t newmark;
+ u_int8_t dscp;
ct = nf_ct_get(skb, &ctinfo);
if (ct == NULL)
@@ -49,12 +50,24 @@ connmark_tg_shift(struct sk_buff *skb, c
switch (info->mode) {
case XT_CONNMARK_SET:
- newmark = (ct->mark & ~info->ctmask) ^ info->ctmark;
- if (info->shift_dir == D_SHIFT_RIGHT)
- newmark >>= info->shift_bits;
- else
- newmark <<= info->shift_bits;
+ newmark = ct->mark;
+ if (info->func & XT_CONNMARK_VALUE) {
+ newmark = (newmark & ~info->ctmask) ^ info->ctmark;
+ if (info->shift_dir == D_SHIFT_RIGHT)
+ newmark >>= info->shift_bits;
+ else
+ newmark <<= info->shift_bits;
+ } else if (info->func & XT_CONNMARK_DSCP) {
+ if (skb->protocol == htons(ETH_P_IP))
+ dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
+ else /* protocol doesn't have diffserv */
+ break;
+ newmark = (newmark & ~info->ctmark) |
+ (info->ctmask | (dscp << info->shift_bits));
+ }
if (ct->mark != newmark) {
ct->mark = newmark;
nf_conntrack_event_cache(IPCT_MARK, ct);
@@ -93,20 +106,36 @@ static unsigned int
connmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_connmark_tginfo1 *info = par->targinfo;
- const struct xt_connmark_tginfo2 info2 = {
+ const struct xt_connmark_tginfo3 info3 = {
.ctmark = info->ctmark,
.ctmask = info->ctmask,
.nfmask = info->nfmask,
.mode = info->mode,
+ .func = XT_CONNMARK_VALUE
};
- return connmark_tg_shift(skb, &info2);
+ return connmark_tg_shift(skb, &info3);
}
static unsigned int
connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_connmark_tginfo2 *info = par->targinfo;
+ const struct xt_connmark_tginfo3 info3 = {
+ .ctmark = info->ctmark,
+ .ctmask = info->ctmask,
+ .nfmask = info->nfmask,
+ .mode = info->mode,
+ .func = XT_CONNMARK_VALUE
+ };
+
+ return connmark_tg_shift(skb, &info3);
+}
+
+static unsigned int
+connmark_tg_v3(struct sk_buff *skb, const struct xt_action_param *par)
+{
+ const struct xt_connmark_tginfo3 *info = par->targinfo;
return connmark_tg_shift(skb, info);
}
@@ -177,6 +206,16 @@ static struct xt_target connmark_tg_reg[
.targetsize = sizeof(struct xt_connmark_tginfo2),
.destroy = connmark_tg_destroy,
.me = THIS_MODULE,
+ },
+ {
+ .name = "CONNMARK",
+ .revision = 3,
+ .family = NFPROTO_UNSPEC,
+ .checkentry = connmark_tg_check,
+ .target = connmark_tg_v3,
+ .targetsize = sizeof(struct xt_connmark_tginfo3),
+ .destroy = connmark_tg_destroy,
+ .me = THIS_MODULE,
}
};