m_mpls: add mac_push action

Add support for the new TCA_MPLS_ACT_MAC_PUSH action (kernel commit
a45294af9e96 ("net/sched: act_mpls: Add action to push MPLS LSE before
Ethernet header")). This action let TC push an MPLS header before the
MAC header of a frame.

Example (encapsulate all outgoing frames with label 20, then add an
outer Ethernet header):
 # tc filter add dev ethX matchall \
       action mpls mac_push label 20 ttl 64 \
       action vlan push_eth dst_mac 0a:00:00:00:00:02 \
                            src_mac 0a:00:00:00:00:01

This patch also adds an alias for ETH_P_TEB, since it is useful when
decapsulating MPLS packets that contain an Ethernet frame.

With MAC_PUSH, there's no previous Ethertype to modify. However, the
"protocol" option is still needed, because the kernel uses it to set
skb->protocol. So rename can_modify_ethtype() to can_set_ethtype().

Also add a test suite for m_mpls, which covers the new action and the
pre-existing ones.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David Ahern <dsahern@gmail.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/testsuite/tests/tc/mpls.t b/testsuite/tests/tc/mpls.t
new file mode 100755
index 000000000..cb25f3619
--- /dev/null
+++ b/testsuite/tests/tc/mpls.t
@@ -0,0 +1,69 @@
+#!/bin/sh
+
+. lib/generic.sh
+
+DEV="$(rand_dev)"
+ts_ip "$0" "Add $DEV dummy interface" link add dev $DEV up type dummy
+ts_tc "$0" "Add ingress qdisc" qdisc add dev $DEV ingress
+
+reset_qdisc()
+{
+	ts_tc "$0" "Remove ingress qdisc" qdisc del dev $DEV ingress
+	ts_tc "$0" "Add ingress qdisc" qdisc add dev $DEV ingress
+}
+
+ts_tc "$0" "Add mpls action pop"                              \
+	filter add dev $DEV ingress protocol mpls_uc matchall \
+	action mpls pop protocol ip
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "mpls"
+test_on "pop protocol ip pipe"
+
+reset_qdisc
+ts_tc "$0" "Add mpls action push"                        \
+	filter add dev $DEV ingress protocol ip matchall \
+	action mpls push protocol mpls_uc label 20 tc 3 bos 1 ttl 64
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "mpls"
+test_on "push"
+test_on "protocol mpls_uc"
+test_on "label 20"
+test_on "tc 3"
+test_on "bos 1"
+test_on "ttl 64"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add mpls action mac_push"        \
+	filter add dev $DEV ingress matchall \
+	action mpls mac_push protocol mpls_uc label 20 tc 3 bos 1 ttl 64
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "mpls"
+test_on "mac_push"
+test_on "protocol mpls_uc"
+test_on "label 20"
+test_on "tc 3"
+test_on "bos 1"
+test_on "ttl 64"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add mpls action modify"                           \
+	filter add dev $DEV ingress protocol mpls_uc matchall \
+	action mpls modify label 20 tc 3 ttl 64
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "mpls"
+test_on "modify"
+test_on "label 20"
+test_on "tc 3"
+test_on "ttl 64"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add mpls action dec_ttl"                          \
+	filter add dev $DEV ingress protocol mpls_uc matchall \
+	action mpls dec_ttl
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "mpls"
+test_on "dec_ttl"
+test_on "pipe"