m_vlan: add pop_eth and push_eth actions

Add support for the new TCA_VLAN_ACT_POP_ETH and TCA_VLAN_ACT_PUSH_ETH
actions (kernel commit 19fbcb36a39e ("net/sched: act_vlan:
Add {POP,PUSH}_ETH actions"). These action let TC remove or add the
Ethernet at the head of a frame.

Drop an Ethernet header:
 # tc filter add dev ethX matchall action vlan pop_eth

Push an Ethernet header (the original frame must have no MAC header):
 # tc filter add dev ethX matchall action vlan \
       push_eth dst_mac 0a:00:00:00:00:02 src_mac 0a:00:00:00:00:01

Also add a test suite for m_vlan, which covers these new actions and
the pre-existing ones.

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

man/man8/tc-vlan.8

@@ -5,8 +5,8 @@ vlan - vlan manipulation module
 .SH SYNOPSIS
 .in +8
 .ti -8
-.BR tc " ... " "action vlan" " { " pop " |"
+.BR tc " ... " "action vlan" " { " pop " | " pop_eth " |"
-.IR PUSH " | " MODIFY " } [ " CONTROL " ]"
+.IR PUSH " | " MODIFY " | " PUSH_ETH " } [ " CONTROL " ]"
 
 .ti -8
 .IR PUSH " := "
@@ -24,6 +24,11 @@ vlan - vlan manipulation module
 .IR VLANPRIO " ] "
 .BI id " VLANID"
 
+.ti -8
+.IR PUSH_ETH " := "
+.B push_eth
+.BI dst_mac " LLADDR " src_mac " LLADDR "
+
 .ti -8
 .IR CONTROL " := { "
 .BR reclassify " | " pipe " | " drop " | " continue " | " pass " | " goto " " chain " " CHAIN_INDEX " }"
@@ -43,6 +48,20 @@ modes require at least a
 and allow to optionally choose the
 .I VLANPROTO
 to use.
+
+The
+.B vlan
+action can also be used to add or remove the base Ethernet header. The
+.B pop_eth
+mode, which takes no argument, is used to remove the base Ethernet header. All
+existing VLANs must have been previously dropped. The opposite operation,
+adding a base Ethernet header, is done with the
+.B push_eth
+mode. In that case, the packet must have no MAC header (stacking MAC headers is
+not permitted). This mode is mostly useful when a previous action has
+encapsulated the whole original frame behind a network header and one needs
+to prepend an Ethernet header before forwarding the resulting packet.
+
 .SH OPTIONS
 .TP
 .B pop
@@ -58,6 +77,16 @@ Replace mode. Existing 802.1Q tag is replaced. Requires at least
 .B id
 option.
 .TP
+.B pop_eth
+Ethernet header decapsulation mode. Only works on a plain Ethernet header:
+VLANs, if any, must be removed first.
+.TP
+.B push_eth
+Ethernet header encapsulation mode. The Ethertype is automatically set
+using the network header type. Chaining Ethernet headers is not allowed: the
+packet must have no MAC header when using this mode. Requires the
+.BR "dst_mac " and " src_mac " options.
+.TP
 .BI id " VLANID"
 Specify the VLAN ID to encapsulate into.
 .I VLANID
@@ -73,6 +102,12 @@ Choose the VLAN protocol to use. At the time of writing, the kernel accepts only
 .BI priority " VLANPRIO"
 Choose the VLAN priority to use. Decimal number in range of 0-7.
 .TP
+.BI dst_mac " LLADDR"
+Choose the destination MAC address to use.
+.TP
+.BI src_mac " LLADDR"
+Choose the source MAC address to use.
+.TP
 .I CONTROL
 How to continue after executing this action.
 .RS

tc/m_vlan.c

@@ -23,6 +23,8 @@ static const char * const action_names[] = {
 	[TCA_VLAN_ACT_POP] = "pop",
 	[TCA_VLAN_ACT_PUSH] = "push",
 	[TCA_VLAN_ACT_MODIFY] = "modify",
+	[TCA_VLAN_ACT_POP_ETH] = "pop_eth",
+	[TCA_VLAN_ACT_PUSH_ETH] = "push_eth",
 };
 
 static void explain(void)
@@ -31,6 +33,8 @@ static void explain(void)
 		"Usage: vlan pop\n"
 		"       vlan push [ protocol VLANPROTO ] id VLANID [ priority VLANPRIO ] [CONTROL]\n"
 		"       vlan modify [ protocol VLANPROTO ] id VLANID [ priority VLANPRIO ] [CONTROL]\n"
+		"       vlan pop_eth [CONTROL]\n"
+		"       vlan push_eth dst_mac LLADDR src_mac LLADDR [CONTROL]\n"
 		"       VLANPROTO is one of 802.1Q or 802.1AD\n"
 		"            with default: 802.1Q\n"
 		"       CONTROL := reclassify | pipe | drop | continue | pass |\n"
@@ -63,6 +67,10 @@ static int parse_vlan(struct action_util *a, int *argc_p, char ***argv_p,
 	char **argv = *argv_p;
 	struct rtattr *tail;
 	int action = 0;
+	char dst_mac[ETH_ALEN] = {};
+	int dst_mac_set = 0;
+	char src_mac[ETH_ALEN] = {};
+	int src_mac_set = 0;
 	__u16 id;
 	int id_set = 0;
 	__u16 proto;
@@ -95,6 +103,18 @@ static int parse_vlan(struct action_util *a, int *argc_p, char ***argv_p,
 				return -1;
 			}
 			action = TCA_VLAN_ACT_MODIFY;
+		} else if (matches(*argv, "pop_eth") == 0) {
+			if (action) {
+				unexpected(*argv);
+				return -1;
+			}
+			action = TCA_VLAN_ACT_POP_ETH;
+		} else if (matches(*argv, "push_eth") == 0) {
+			if (action) {
+				unexpected(*argv);
+				return -1;
+			}
+			action = TCA_VLAN_ACT_PUSH_ETH;
 		} else if (matches(*argv, "id") == 0) {
 			if (!has_push_attribs(action))
 				invarg("only valid for push/modify", *argv);
@@ -119,6 +139,22 @@ static int parse_vlan(struct action_util *a, int *argc_p, char ***argv_p,
 			if (get_u8(&prio, *argv, 0) || (prio & ~0x7))
 				invarg("prio is invalid", *argv);
 			prio_set = 1;
+		} else if (matches(*argv, "dst_mac") == 0) {
+			if (action != TCA_VLAN_ACT_PUSH_ETH)
+				invarg("only valid for push_eth", *argv);
+
+			NEXT_ARG();
+			if (ll_addr_a2n(dst_mac, sizeof(dst_mac), *argv) < 0)
+				invarg("dst_mac is invalid", *argv);
+			dst_mac_set = 1;
+		} else if (matches(*argv, "src_mac") == 0) {
+			if (action != TCA_VLAN_ACT_PUSH_ETH)
+				invarg("only valid for push_eth", *argv);
+
+			NEXT_ARG();
+			if (ll_addr_a2n(src_mac, sizeof(src_mac), *argv) < 0)
+				invarg("src_mac is invalid", *argv);
+			src_mac_set = 1;
 		} else if (matches(*argv, "help") == 0) {
 			usage();
 		} else {
@@ -150,6 +186,20 @@ static int parse_vlan(struct action_util *a, int *argc_p, char ***argv_p,
 		return -1;
 	}
 
+	if (action == TCA_VLAN_ACT_PUSH_ETH) {
+		if (!dst_mac_set) {
+			fprintf(stderr, "dst_mac needs to be set for %s\n",
+				action_names[action]);
+			explain();
+			return -1;
+		} else if (!src_mac_set) {
+			fprintf(stderr, "src_mac needs to be set for %s\n",
+				action_names[action]);
+			explain();
+			return -1;
+		}
+	}
+
 	parm.v_action = action;
 	tail = addattr_nest(n, MAX_MSG, tca_id);
 	addattr_l(n, MAX_MSG, TCA_VLAN_PARMS, &parm, sizeof(parm));
@@ -167,6 +217,12 @@ static int parse_vlan(struct action_util *a, int *argc_p, char ***argv_p,
 	}
 	if (prio_set)
 		addattr8(n, MAX_MSG, TCA_VLAN_PUSH_VLAN_PRIORITY, prio);
+	if (dst_mac_set)
+		addattr_l(n, MAX_MSG, TCA_VLAN_PUSH_ETH_DST, dst_mac,
+			  sizeof(dst_mac));
+	if (src_mac_set)
+		addattr_l(n, MAX_MSG, TCA_VLAN_PUSH_ETH_SRC, src_mac,
+			  sizeof(src_mac));
 
 	addattr_nest_end(n, tail);
 
@@ -216,6 +272,19 @@ static int print_vlan(struct action_util *au, FILE *f, struct rtattr *arg)
 			print_uint(PRINT_ANY, "priority", " priority %u", val);
 		}
 		break;
+	case TCA_VLAN_ACT_PUSH_ETH:
+		if (tb[TCA_VLAN_PUSH_ETH_DST] &&
+		    RTA_PAYLOAD(tb[TCA_VLAN_PUSH_ETH_DST]) == ETH_ALEN) {
+			ll_addr_n2a(RTA_DATA(tb[TCA_VLAN_PUSH_ETH_DST]),
+				    ETH_ALEN, 0, b1, sizeof(b1));
+			print_string(PRINT_ANY, "dst_mac", " dst_mac %s", b1);
+		}
+		if (tb[TCA_VLAN_PUSH_ETH_SRC &&
+		       RTA_PAYLOAD(tb[TCA_VLAN_PUSH_ETH_SRC]) == ETH_ALEN]) {
+			ll_addr_n2a(RTA_DATA(tb[TCA_VLAN_PUSH_ETH_SRC]),
+				    ETH_ALEN, 0, b1, sizeof(b1));
+			print_string(PRINT_ANY, "src_mac", " src_mac %s", b1);
+		}
 	}
 	print_action_control(f, " ", parm->action, "");
 

testsuite/tests/tc/vlan.t

@@ -0,0 +1,86 @@
+#!/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 vlan action pop" \
+	filter add dev $DEV ingress matchall action vlan pop
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "pop"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action push (default parameters)" \
+	filter add dev $DEV ingress matchall action vlan push id 5
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "push"
+test_on "id 5"
+test_on "protocol 802.1Q"
+test_on "priority 0"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action push (explicit parameters)" \
+	filter add dev $DEV ingress matchall            \
+	action vlan push id 5 protocol 802.1ad priority 2
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "push"
+test_on "id 5"
+test_on "protocol 802.1ad"
+test_on "priority 2"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action modify (default parameters)" \
+	filter add dev $DEV ingress matchall action vlan modify id 5
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "modify"
+test_on "id 5"
+test_on "protocol 802.1Q"
+test_on "priority 0"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action modify (explicit parameters)" \
+	filter add dev $DEV ingress matchall              \
+	action vlan modify id 5 protocol 802.1ad priority 2
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "modify"
+test_on "id 5"
+test_on "protocol 802.1ad"
+test_on "priority 2"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action pop_eth" \
+	filter add dev $DEV ingress matchall action vlan pop_eth
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "pop_eth"
+test_on "pipe"
+
+reset_qdisc
+ts_tc "$0" "Add vlan action push_eth"                  \
+	filter add dev $DEV ingress matchall           \
+	action vlan push_eth dst_mac 02:00:00:00:00:02 \
+	src_mac 02:00:00:00:00:01
+ts_tc "$0" "Show ingress filters" filter show dev $DEV ingress
+test_on "vlan"
+test_on "push_eth"
+test_on "dst_mac 02:00:00:00:00:02"
+test_on "src_mac 02:00:00:00:00:01"
+test_on "pipe"