From 0afe12a4a9471ed1343693338ec6350dc66ba295 Mon Sep 17 00:00:00 2001

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From: Andrea Claudi <aclaudi@redhat.com>

Date: Fri, 29 Jan 2021 00:35:03 +0100

Subject: [PATCH] m_mpls: add mac_push action

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1885770

Upstream Status: unknown commit 02a261b5

commit 02a261b5ba1c8580ac2a35bc6c87faa2ec9f5c96

Author: Guillaume Nault <gnault@redhat.com>

Date:   Mon Oct 19 17:23:08 2020 +0200

    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>

---

 lib/ll_proto.c            |  1 +

 man/man8/tc-mpls.8        | 44 +++++++++++++++++++++++--

 man/man8/tc-vlan.8        |  5 ++-

 tc/m_mpls.c               | 43 ++++++++++++++++--------

 testsuite/tests/tc/mpls.t | 69 +++++++++++++++++++++++++++++++++++++++

 5 files changed, 145 insertions(+), 17 deletions(-)

 create mode 100755 testsuite/tests/tc/mpls.t

diff --git a/lib/ll_proto.c b/lib/ll_proto.c

index 2a0c1cb3..78179311 100644

--- a/lib/ll_proto.c

+++ b/lib/ll_proto.c

@@ -80,6 +80,7 @@ __PF(8021Q,802.1Q)

 __PF(8021AD,802.1ad)

 __PF(MPLS_UC,mpls_uc)

 __PF(MPLS_MC,mpls_mc)

+__PF(TEB,teb)

 { 0x8100, "802.1Q" },

 { 0x88cc, "LLDP" },

diff --git a/man/man8/tc-mpls.8 b/man/man8/tc-mpls.8

index 84ef2ef1..9e563e98 100644

--- a/man/man8/tc-mpls.8

+++ b/man/man8/tc-mpls.8

@@ -17,7 +17,7 @@ mpls - mpls manipulation module

 .ti -8

 .IR PUSH " := "

-.BR push " [ " protocol

+.RB "{ " push " | " mac_push " } [ " protocol

 .IR MPLS_PROTO " ]"

 .RB " [ " tc

 .IR MPLS_TC " ] "

@@ -64,7 +64,14 @@ requires no arguments and simply subtracts 1 from the MPLS header TTL field.

 Decapsulation mode. Requires the protocol of the next header.

 .TP

 .B push

-Encapsulation mode. Requires at least the

+Encapsulation mode. Adds the MPLS header between the MAC and the network

+headers. Requires at least the

+.B label

+option.

+.TP

+.B mac_push

+Encapsulation mode. Adds the MPLS header before the MAC header. Requires at

+least the

 .B label

 option.

 .TP

@@ -152,5 +159,36 @@ ip packets and output to eth1:

 .EE

 .RE

+Here is another example, where incoming Ethernet frames are encapsulated into

+MPLS with label 123 and TTL 64. Then, an outer Ethernet header is added and the

+resulting frame is finally sent on eth1:

+

+.RS

+.EX

+#tc qdisc add dev eth0 ingress

+#tc filter add dev eth0 ingress matchall \\

+	action mpls mac_push label 123 ttl 64 \\

+	action vlan push_eth \\

+		dst_mac 02:00:00:00:00:02 \\

+		src_mac 02:00:00:00:00:01 \\

+	action mirred egress redirect dev eth1

+.EE

+.RE

+

+The following example assumes that incoming MPLS packets with label 123

+transport Ethernet frames. The outer Ethernet and the MPLS headers are

+stripped, then the inner Ethernet frame is sent on eth1:

+

+.RS

+.EX

+#tc qdisc add dev eth0 ingress

+#tc filter add dev eth0 ingress protocol mpls_uc \\

+	flower mpls_label 123 mpls_bos 1 \\

+	action vlan pop_eth \\

+	action mpls pop protocol teb \\

+	action mirred egress redirect dev eth1

+.EE

+.RE

+

 .SH SEE ALSO

-.BR tc (8)

+.BR tc "(8), " tc-mirred "(8), " tc-vlan (8)

diff --git a/man/man8/tc-vlan.8 b/man/man8/tc-vlan.8

index 5c2808b1..264053d3 100644

--- a/man/man8/tc-vlan.8

+++ b/man/man8/tc-vlan.8

@@ -157,5 +157,8 @@ process then restarted for the plain packet:

 .EE

 .RE

+For an example of the

+.BR pop_eth " and " push_eth " modes, see " tc-mpls (8).

+

 .SH SEE ALSO

-.BR tc (8)

+.BR tc "(8), " tc-mpls (8)

diff --git a/tc/m_mpls.c b/tc/m_mpls.c

index 3d5d9b25..cb8019b1 100644

--- a/tc/m_mpls.c

+++ b/tc/m_mpls.c

@@ -17,6 +17,7 @@ static const char * const action_names[] = {

 	[TCA_MPLS_ACT_PUSH] = "push",

 	[TCA_MPLS_ACT_MODIFY] = "modify",

 	[TCA_MPLS_ACT_DEC_TTL] = "dec_ttl",

+	[TCA_MPLS_ACT_MAC_PUSH] = "mac_push",

 };

 static void explain(void)

@@ -25,9 +26,11 @@ static void explain(void)

 		"Usage: mpls pop [ protocol MPLS_PROTO ]\n"

 		"       mpls push [ protocol MPLS_PROTO ] [ label MPLS_LABEL ] [ tc MPLS_TC ]\n"

 		"                 [ ttl MPLS_TTL ] [ bos MPLS_BOS ] [CONTROL]\n"

+		"       mpls mac_push [ protocol MPLS_PROTO ] [ label MPLS_LABEL ] [ tc MPLS_TC ]\n"

+		"                     [ ttl MPLS_TTL ] [ bos MPLS_BOS ] [CONTROL]\n"

 		"       mpls modify [ label MPLS_LABEL ] [ tc MPLS_TC ] [ ttl MPLS_TTL ] [CONTROL]\n"

-		"           for pop MPLS_PROTO is next header of packet - e.g. ip or mpls_uc\n"

-		"           for push MPLS_PROTO is one of mpls_uc or mpls_mc\n"

+		"           for pop, MPLS_PROTO is next header of packet - e.g. ip or mpls_uc\n"

+		"           for push and mac_push, MPLS_PROTO is one of mpls_uc or mpls_mc\n"

 		"               with default: mpls_uc\n"

 		"       CONTROL := reclassify | pipe | drop | continue | pass |\n"

 		"                  goto chain <CHAIN_INDEX>\n");

@@ -41,12 +44,14 @@ static void usage(void)

 static bool can_modify_mpls_fields(unsigned int action)

 {

-	return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_MODIFY;

+	return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_MAC_PUSH ||

+		action == TCA_MPLS_ACT_MODIFY;

 }

-static bool can_modify_ethtype(unsigned int action)

+static bool can_set_ethtype(unsigned int action)

 {

-	return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_POP;

+	return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_MAC_PUSH ||

+		action == TCA_MPLS_ACT_POP;

 }

 static bool is_valid_label(__u32 label)

@@ -94,6 +99,10 @@ static int parse_mpls(struct action_util *a, int *argc_p, char ***argv_p,

 			if (check_double_action(action, *argv))

 				return -1;

 			action = TCA_MPLS_ACT_PUSH;

+		} else if (matches(*argv, "mac_push") == 0) {

+			if (check_double_action(action, *argv))

+				return -1;

+			action = TCA_MPLS_ACT_MAC_PUSH;

 		} else if (matches(*argv, "modify") == 0) {

 			if (check_double_action(action, *argv))

 				return -1;

@@ -104,31 +113,36 @@ static int parse_mpls(struct action_util *a, int *argc_p, char ***argv_p,

 			action = TCA_MPLS_ACT_DEC_TTL;

 		} else if (matches(*argv, "label") == 0) {

 			if (!can_modify_mpls_fields(action))

-				invarg("only valid for push/modify", *argv);

+				invarg("only valid for push, mac_push and modify",

+				       *argv);

 			NEXT_ARG();

 			if (get_u32(&label, *argv, 0) || !is_valid_label(label))

 				invarg("label must be <=0xFFFFF", *argv);

 		} else if (matches(*argv, "tc") == 0) {

 			if (!can_modify_mpls_fields(action))

-				invarg("only valid for push/modify", *argv);

+				invarg("only valid for push, mac_push and modify",

+				       *argv);

 			NEXT_ARG();

 			if (get_u8(&tc, *argv, 0) || (tc & ~0x7))

 				invarg("tc field is 3 bits max", *argv);

 		} else if (matches(*argv, "ttl") == 0) {

 			if (!can_modify_mpls_fields(action))

-				invarg("only valid for push/modify", *argv);

+				invarg("only valid for push, mac_push and modify",

+				       *argv);

 			NEXT_ARG();

 			if (get_u8(&ttl, *argv, 0) || !ttl)

 				invarg("ttl must be >0 and <=255", *argv);

 		} else if (matches(*argv, "bos") == 0) {

 			if (!can_modify_mpls_fields(action))

-				invarg("only valid for push/modify", *argv);

+				invarg("only valid for push, mac_push and modify",

+				       *argv);

 			NEXT_ARG();

 			if (get_u8(&bos, *argv, 0) || (bos & ~0x1))

 				invarg("bos must be 0 or 1", *argv);

 		} else if (matches(*argv, "protocol") == 0) {

-			if (!can_modify_ethtype(action))

-				invarg("only valid for push/pop", *argv);

+			if (!can_set_ethtype(action))

+				invarg("only valid for push, mac_push and pop",

+				       *argv);

 			NEXT_ARG();

 			if (ll_proto_a2n(&proto, *argv))

 				invarg("protocol is invalid", *argv);

@@ -159,10 +173,12 @@ static int parse_mpls(struct action_util *a, int *argc_p, char ***argv_p,

 	if (action == TCA_MPLS_ACT_PUSH && label == 0xffffffff)

 		missarg("label");

-	if (action == TCA_MPLS_ACT_PUSH && proto &&

+	if ((action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_MAC_PUSH) &&

+	    proto &&

 	    proto != htons(ETH_P_MPLS_UC) && proto != htons(ETH_P_MPLS_MC)) {

 		fprintf(stderr,

-			"invalid push protocol \"0x%04x\" - use mpls_(uc|mc)\n",

+			"invalid %spush protocol \"0x%04x\" - use mpls_(uc|mc)\n",

+			action == TCA_MPLS_ACT_MAC_PUSH ? "mac_" : "",

 			ntohs(proto));

 		return -1;

 	}

@@ -223,6 +239,7 @@ static int print_mpls(struct action_util *au, FILE *f, struct rtattr *arg)

 		}

 		break;

 	case TCA_MPLS_ACT_PUSH:

+	case TCA_MPLS_ACT_MAC_PUSH:

 		if (tb[TCA_MPLS_PROTO]) {

 			__u16 proto;

diff --git a/testsuite/tests/tc/mpls.t b/testsuite/tests/tc/mpls.t

new file mode 100755

index 00000000..cb25f361

--- /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"

-- 

2.29.2