test_xdp_vlan.sh isn't used by the BPF CI.

Migrate test_xdp_vlan.sh in prog_tests/xdp_vlan.c.
It uses the same BPF programs located in progs/test_xdp_vlan.c and the
same network topology.
Remove test_xdp_vlan*.sh and their Makefile entries.

Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
---
 tools/testing/selftests/bpf/Makefile               |   4 +-
 tools/testing/selftests/bpf/prog_tests/xdp_vlan.c  | 175 ++++++++++++++++
 tools/testing/selftests/bpf/test_xdp_vlan.sh       | 233 ---------------------
 .../selftests/bpf/test_xdp_vlan_mode_generic.sh    |   9 -
 .../selftests/bpf/test_xdp_vlan_mode_native.sh     |   9 -
 5 files changed, 176 insertions(+), 254 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 5dc9c84ed30f6e5a46572a9e428f692a79623469..09c1f731b8280696c729e3c87020ef749fee9dcb 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -103,8 +103,6 @@ TEST_PROGS := test_kmod.sh \
 	test_tunnel.sh \
 	test_lwt_seg6local.sh \
 	test_lirc_mode2.sh \
-	test_xdp_vlan_mode_generic.sh \
-	test_xdp_vlan_mode_native.sh \
 	test_lwt_ip_encap.sh \
 	test_tc_tunnel.sh \
 	test_tc_edt.sh \
@@ -118,7 +116,7 @@ TEST_PROGS := test_kmod.sh \
 
 TEST_PROGS_EXTENDED := \
 	ima_setup.sh verify_sig_setup.sh \
-	test_xdp_vlan.sh test_bpftool.py
+	test_bpftool.py
 
 TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
 	bpf_test_modorder_y.ko
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
new file mode 100644
index 0000000000000000000000000000000000000000..18dd25344de768aa83a162a0c091f28a4e5f505e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Network topology:
+ *  -----------        -----------
+ *  |  NS1    |        |   NS2   |
+ *  | veth0  -|--------|- veth0  |
+ *  -----------        -----------
+ *
+ */
+
+#define _GNU_SOURCE
+#include <net/if.h>
+#include <uapi/linux/if_link.h>
+
+#include "network_helpers.h"
+#include "test_progs.h"
+#include "test_xdp_vlan.skel.h"
+
+
+#define VETH_NAME	"veth0"
+#define NS_MAX_SIZE	32
+#define NS1_NAME	"ns-xdp-vlan-1-"
+#define NS2_NAME	"ns-xdp-vlan-2-"
+#define NS1_IP_ADDR	"100.64.10.1"
+#define NS2_IP_ADDR	"100.64.10.2"
+#define VLAN_ID		4011
+
+static int setup_network(char *ns1, char *ns2)
+{
+	if (!ASSERT_OK(append_tid(ns1, NS_MAX_SIZE), "create ns1 name"))
+		goto fail;
+	if (!ASSERT_OK(append_tid(ns2, NS_MAX_SIZE), "create ns2 name"))
+		goto fail;
+
+	SYS(fail, "ip netns add %s", ns1);
+	SYS(fail, "ip netns add %s", ns2);
+	SYS(fail, "ip -n %s link add %s type veth peer name %s netns %s",
+	    ns1, VETH_NAME, VETH_NAME, ns2);
+
+	/* NOTICE: XDP require VLAN header inside packet payload
+	 *  - Thus, disable VLAN offloading driver features
+	 */
+	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns1, VETH_NAME);
+	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns2, VETH_NAME);
+
+	/* NS1 configuration */
+	SYS(fail, "ip -n %s addr add %s/24 dev %s", ns1, NS1_IP_ADDR, VETH_NAME);
+	SYS(fail, "ip -n %s link set %s up", ns1, VETH_NAME);
+
+	/* NS2 configuration */
+	SYS(fail, "ip -n %s link add link %s name %s.%d type vlan id %d",
+	    ns2, VETH_NAME, VETH_NAME, VLAN_ID, VLAN_ID);
+	SYS(fail, "ip -n %s addr add %s/24 dev %s.%d", ns2, NS2_IP_ADDR, VETH_NAME, VLAN_ID);
+	SYS(fail, "ip -n %s link set %s up", ns2, VETH_NAME);
+	SYS(fail, "ip -n %s link set %s.%d up", ns2, VETH_NAME, VLAN_ID);
+
+	/* At this point ping should fail because VLAN tags are only used by NS2 */
+	return !SYS_NOFAIL("ip netns exec %s ping -W 1 -c1 %s", ns2, NS1_IP_ADDR);
+
+fail:
+	return -1;
+}
+
+static void cleanup_network(const char *ns1, const char *ns2)
+{
+	SYS_NOFAIL("ip netns del %s", ns1);
+	SYS_NOFAIL("ip netns del %s", ns2);
+}
+
+static void xdp_vlan(struct bpf_program *xdp, struct bpf_program *tc, u32 flags)
+{
+	LIBBPF_OPTS(bpf_tc_hook, tc_hook, .attach_point = BPF_TC_EGRESS);
+	LIBBPF_OPTS(bpf_tc_opts, tc_opts, .handle = 1, .priority = 1);
+	char ns1[NS_MAX_SIZE] = NS1_NAME;
+	char ns2[NS_MAX_SIZE] = NS2_NAME;
+	struct nstoken *nstoken = NULL;
+	int interface;
+	int ret;
+
+	if (!ASSERT_OK(setup_network(ns1, ns2), "setup network"))
+		goto cleanup;
+
+	nstoken = open_netns(ns1);
+	if (!ASSERT_OK_PTR(nstoken, "open NS1"))
+		goto cleanup;
+
+	interface = if_nametoindex(VETH_NAME);
+	if (!ASSERT_NEQ(interface, 0, "get interface index"))
+		goto cleanup;
+
+	ret = bpf_xdp_attach(interface, bpf_program__fd(xdp), flags, NULL);
+	if (!ASSERT_OK(ret, "attach xdp_vlan_change"))
+		goto cleanup;
+
+	tc_hook.ifindex = interface;
+	ret = bpf_tc_hook_create(&tc_hook);
+	if (!ASSERT_OK(ret, "bpf_tc_hook_create"))
+		goto detach_xdp;
+
+	/* Now we'll use BPF programs to pop/push the VLAN tags */
+	tc_opts.prog_fd = bpf_program__fd(tc);
+	ret = bpf_tc_attach(&tc_hook, &tc_opts);
+	if (!ASSERT_OK(ret, "bpf_tc_attach"))
+		goto detach_xdp;
+
+	close_netns(nstoken);
+	nstoken = NULL;
+
+	/* Now the namespaces can reach each-other, test with pings */
+	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns1, NS2_IP_ADDR);
+	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns2, NS1_IP_ADDR);
+
+
+detach_tc:
+	bpf_tc_detach(&tc_hook, &tc_opts);
+detach_xdp:
+	bpf_xdp_detach(interface, flags, NULL);
+cleanup:
+	close_netns(nstoken);
+	cleanup_network(ns1, ns2);
+}
+
+/* First test: Remove VLAN by setting VLAN ID 0, using "xdp_vlan_change"
+ * egress use TC to add back VLAN tag 4011
+ */
+void test_xdp_vlan_change(void)
+{
+	struct test_xdp_vlan *skel;
+
+	skel = test_xdp_vlan__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "xdp_vlan__open_and_load"))
+		return;
+
+	if (test__start_subtest("0"))
+		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push, 0);
+
+	if (test__start_subtest("DRV_MODE"))
+		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push,
+			 XDP_FLAGS_DRV_MODE);
+
+	if (test__start_subtest("SKB_MODE"))
+		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push,
+			 XDP_FLAGS_SKB_MODE);
+
+	test_xdp_vlan__destroy(skel);
+}
+
+/* Second test: XDP prog fully remove vlan header
+ *
+ * Catch kernel bug for generic-XDP, that doesn't allow us to
+ * remove a VLAN header, because skb->protocol still contain VLAN
+ * ETH_P_8021Q indication, and this cause overwriting of our changes.
+ */
+void test_xdp_vlan_remove(void)
+{
+	struct test_xdp_vlan *skel;
+
+	skel = test_xdp_vlan__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "xdp_vlan__open_and_load"))
+		return;
+
+	if (test__start_subtest("0"))
+		xdp_vlan(skel->progs.xdp_vlan_remove_outer2, skel->progs.tc_vlan_push, 0);
+
+	if (test__start_subtest("DRV_MODE"))
+		xdp_vlan(skel->progs.xdp_vlan_remove_outer2, skel->progs.tc_vlan_push,
+			 XDP_FLAGS_DRV_MODE);
+
+	if (test__start_subtest("SKB_MODE"))
+		xdp_vlan(skel->progs.xdp_vlan_remove_outer2, skel->progs.tc_vlan_push,
+			 XDP_FLAGS_SKB_MODE);
+
+	test_xdp_vlan__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/test_xdp_vlan.sh b/tools/testing/selftests/bpf/test_xdp_vlan.sh
deleted file mode 100755
index 7f672a040b312952679348721a5a17b8703cfc4b..0000000000000000000000000000000000000000
--- a/tools/testing/selftests/bpf/test_xdp_vlan.sh
+++ /dev/null
@@ -1,233 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-# Author: Jesper Dangaard Brouer <hawk@kernel.org>
-
-# Kselftest framework requirement - SKIP code is 4.
-readonly KSFT_SKIP=4
-readonly NS1="ns1-$(mktemp -u XXXXXX)"
-readonly NS2="ns2-$(mktemp -u XXXXXX)"
-
-# Allow wrapper scripts to name test
-if [ -z "$TESTNAME" ]; then
-    TESTNAME=xdp_vlan
-fi
-
-# Default XDP mode
-XDP_MODE=xdpgeneric
-
-usage() {
-  echo "Testing XDP + TC eBPF VLAN manipulations: $TESTNAME"
-  echo ""
-  echo "Usage: $0 [-vfh]"
-  echo "  -v | --verbose : Verbose"
-  echo "  --flush        : Flush before starting (e.g. after --interactive)"
-  echo "  --interactive  : Keep netns setup running after test-run"
-  echo "  --mode=XXX     : Choose XDP mode (xdp | xdpgeneric | xdpdrv)"
-  echo ""
-}
-
-valid_xdp_mode()
-{
-	local mode=$1
-
-	case "$mode" in
-		xdpgeneric | xdpdrv | xdp)
-			return 0
-			;;
-		*)
-			return 1
-	esac
-}
-
-cleanup()
-{
-	local status=$?
-
-	if [ "$status" = "0" ]; then
-		echo "selftests: $TESTNAME [PASS]";
-	else
-		echo "selftests: $TESTNAME [FAILED]";
-	fi
-
-	if [ -n "$INTERACTIVE" ]; then
-		echo "Namespace setup still active explore with:"
-		echo " ip netns exec ${NS1} bash"
-		echo " ip netns exec ${NS2} bash"
-		exit $status
-	fi
-
-	set +e
-	ip link del veth1 2> /dev/null
-	ip netns del ${NS1} 2> /dev/null
-	ip netns del ${NS2} 2> /dev/null
-}
-
-# Using external program "getopt" to get --long-options
-OPTIONS=$(getopt -o hvfi: \
-    --long verbose,flush,help,interactive,debug,mode: -- "$@")
-if (( $? != 0 )); then
-    usage
-    echo "selftests: $TESTNAME [FAILED] Error calling getopt, unknown option?"
-    exit 2
-fi
-eval set -- "$OPTIONS"
-
-##  --- Parse command line arguments / parameters ---
-while true; do
-	case "$1" in
-	    -v | --verbose)
-		export VERBOSE=yes
-		shift
-		;;
-	    -i | --interactive | --debug )
-		INTERACTIVE=yes
-		shift
-		;;
-	    -f | --flush )
-		cleanup
-		shift
-		;;
-	    --mode )
-		shift
-		XDP_MODE=$1
-		shift
-		;;
-	    -- )
-		shift
-		break
-		;;
-	    -h | --help )
-		usage;
-		echo "selftests: $TESTNAME [SKIP] usage help info requested"
-		exit $KSFT_SKIP
-		;;
-	    * )
-		shift
-		break
-		;;
-	esac
-done
-
-if [ "$EUID" -ne 0 ]; then
-	echo "selftests: $TESTNAME [FAILED] need root privileges"
-	exit 1
-fi
-
-valid_xdp_mode $XDP_MODE
-if [ $? -ne 0 ]; then
-	echo "selftests: $TESTNAME [FAILED] unknown XDP mode ($XDP_MODE)"
-	exit 1
-fi
-
-ip link set dev lo xdpgeneric off 2>/dev/null > /dev/null
-if [ $? -ne 0 ]; then
-	echo "selftests: $TESTNAME [SKIP] need ip xdp support"
-	exit $KSFT_SKIP
-fi
-
-# Interactive mode likely require us to cleanup netns
-if [ -n "$INTERACTIVE" ]; then
-	ip link del veth1 2> /dev/null
-	ip netns del ${NS1} 2> /dev/null
-	ip netns del ${NS2} 2> /dev/null
-fi
-
-# Exit on failure
-set -e
-
-# Some shell-tools dependencies
-which ip > /dev/null
-which tc > /dev/null
-which ethtool > /dev/null
-
-# Make rest of shell verbose, showing comments as doc/info
-if [ -n "$VERBOSE" ]; then
-    set -v
-fi
-
-# Create two namespaces
-ip netns add ${NS1}
-ip netns add ${NS2}
-
-# Run cleanup if failing or on kill
-trap cleanup 0 2 3 6 9
-
-# Create veth pair
-ip link add veth1 type veth peer name veth2
-
-# Move veth1 and veth2 into the respective namespaces
-ip link set veth1 netns ${NS1}
-ip link set veth2 netns ${NS2}
-
-# NOTICE: XDP require VLAN header inside packet payload
-#  - Thus, disable VLAN offloading driver features
-#  - For veth REMEMBER TX side VLAN-offload
-#
-# Disable rx-vlan-offload (mostly needed on ns1)
-ip netns exec ${NS1} ethtool -K veth1 rxvlan off
-ip netns exec ${NS2} ethtool -K veth2 rxvlan off
-#
-# Disable tx-vlan-offload (mostly needed on ns2)
-ip netns exec ${NS2} ethtool -K veth2 txvlan off
-ip netns exec ${NS1} ethtool -K veth1 txvlan off
-
-export IPADDR1=100.64.41.1
-export IPADDR2=100.64.41.2
-
-# In ns1/veth1 add IP-addr on plain net_device
-ip netns exec ${NS1} ip addr add ${IPADDR1}/24 dev veth1
-ip netns exec ${NS1} ip link set veth1 up
-
-# In ns2/veth2 create VLAN device
-export VLAN=4011
-export DEVNS2=veth2
-ip netns exec ${NS2} ip link add link $DEVNS2 name $DEVNS2.$VLAN type vlan id $VLAN
-ip netns exec ${NS2} ip addr add ${IPADDR2}/24 dev $DEVNS2.$VLAN
-ip netns exec ${NS2} ip link set $DEVNS2 up
-ip netns exec ${NS2} ip link set $DEVNS2.$VLAN up
-
-# Bringup lo in netns (to avoids confusing people using --interactive)
-ip netns exec ${NS1} ip link set lo up
-ip netns exec ${NS2} ip link set lo up
-
-# At this point, the hosts cannot reach each-other,
-# because ns2 are using VLAN tags on the packets.
-
-ip netns exec ${NS2} sh -c 'ping -W 1 -c 1 100.64.41.1 || echo "Success: First ping must fail"'
-
-
-# Now we can use the test_xdp_vlan.c program to pop/push these VLAN tags
-# ----------------------------------------------------------------------
-# In ns1: ingress use XDP to remove VLAN tags
-export DEVNS1=veth1
-export BPF_FILE=test_xdp_vlan.bpf.o
-
-# First test: Remove VLAN by setting VLAN ID 0, using "xdp_vlan_change"
-export XDP_PROG=xdp_vlan_change
-ip netns exec ${NS1} ip link set $DEVNS1 $XDP_MODE object $BPF_FILE program $XDP_PROG
-
-# In ns1: egress use TC to add back VLAN tag 4011
-#  (del cmd)
-#  tc qdisc del dev $DEVNS1 clsact 2> /dev/null
-#
-ip netns exec ${NS1} tc qdisc add dev $DEVNS1 clsact
-ip netns exec ${NS1} tc filter add dev $DEVNS1 egress \
-  prio 1 handle 1 bpf da obj $BPF_FILE program tc_vlan_push
-
-# Now the namespaces can reach each-other, test with ping:
-ip netns exec ${NS2} ping -i 0.2 -W 2 -c 2 $IPADDR1
-ip netns exec ${NS1} ping -i 0.2 -W 2 -c 2 $IPADDR2
-
-# Second test: Replace xdp prog, that fully remove vlan header
-#
-# Catch kernel bug for generic-XDP, that does didn't allow us to
-# remove a VLAN header, because skb->protocol still contain VLAN
-# ETH_P_8021Q indication, and this cause overwriting of our changes.
-#
-export XDP_PROG=xdp_vlan_remove_outer2
-ip netns exec ${NS1} ip link set $DEVNS1 $XDP_MODE off
-ip netns exec ${NS1} ip link set $DEVNS1 $XDP_MODE object $BPF_FILE program $XDP_PROG
-
-# Now the namespaces should still be able reach each-other, test with ping:
-ip netns exec ${NS2} ping -i 0.2 -W 2 -c 2 $IPADDR1
-ip netns exec ${NS1} ping -i 0.2 -W 2 -c 2 $IPADDR2
diff --git a/tools/testing/selftests/bpf/test_xdp_vlan_mode_generic.sh b/tools/testing/selftests/bpf/test_xdp_vlan_mode_generic.sh
deleted file mode 100755
index c515326d6d59c64fe225fee82463dd43d5ae004e..0000000000000000000000000000000000000000
--- a/tools/testing/selftests/bpf/test_xdp_vlan_mode_generic.sh
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-
-# Exit on failure
-set -e
-
-# Wrapper script to test generic-XDP
-export TESTNAME=xdp_vlan_mode_generic
-./test_xdp_vlan.sh --mode=xdpgeneric
diff --git a/tools/testing/selftests/bpf/test_xdp_vlan_mode_native.sh b/tools/testing/selftests/bpf/test_xdp_vlan_mode_native.sh
deleted file mode 100755
index 5cf7ce1f16c162f6596cfdd14fc214b86271ad7e..0000000000000000000000000000000000000000
--- a/tools/testing/selftests/bpf/test_xdp_vlan_mode_native.sh
+++ /dev/null
@@ -1,9 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-
-# Exit on failure
-set -e
-
-# Wrapper script to test native-XDP
-export TESTNAME=xdp_vlan_mode_native
-./test_xdp_vlan.sh --mode=xdpdrv

-- 
2.48.1

On 02/21, Bastien Curutchet (eBPF Foundation) wrote:
> test_xdp_vlan.sh isn't used by the BPF CI.
> 
> Migrate test_xdp_vlan.sh in prog_tests/xdp_vlan.c.
> It uses the same BPF programs located in progs/test_xdp_vlan.c and the
> same network topology.
> Remove test_xdp_vlan*.sh and their Makefile entries.
> 
> Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
> ---
>  tools/testing/selftests/bpf/Makefile               |   4 +-
>  tools/testing/selftests/bpf/prog_tests/xdp_vlan.c  | 175 ++++++++++++++++
>  tools/testing/selftests/bpf/test_xdp_vlan.sh       | 233 ---------------------
>  .../selftests/bpf/test_xdp_vlan_mode_generic.sh    |   9 -
>  .../selftests/bpf/test_xdp_vlan_mode_native.sh     |   9 -
>  5 files changed, 176 insertions(+), 254 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 5dc9c84ed30f6e5a46572a9e428f692a79623469..09c1f731b8280696c729e3c87020ef749fee9dcb 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -103,8 +103,6 @@ TEST_PROGS := test_kmod.sh \
>  	test_tunnel.sh \
>  	test_lwt_seg6local.sh \
>  	test_lirc_mode2.sh \
> -	test_xdp_vlan_mode_generic.sh \
> -	test_xdp_vlan_mode_native.sh \
>  	test_lwt_ip_encap.sh \
>  	test_tc_tunnel.sh \
>  	test_tc_edt.sh \
> @@ -118,7 +116,7 @@ TEST_PROGS := test_kmod.sh \
>  
>  TEST_PROGS_EXTENDED := \
>  	ima_setup.sh verify_sig_setup.sh \
> -	test_xdp_vlan.sh test_bpftool.py
> +	test_bpftool.py
>  
>  TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
>  	bpf_test_modorder_y.ko
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..18dd25344de768aa83a162a0c091f28a4e5f505e
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
> @@ -0,0 +1,175 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Network topology:
> + *  -----------        -----------
> + *  |  NS1    |        |   NS2   |
> + *  | veth0  -|--------|- veth0  |
> + *  -----------        -----------
> + *
> + */
> +
> +#define _GNU_SOURCE
> +#include <net/if.h>
> +#include <uapi/linux/if_link.h>
> +
> +#include "network_helpers.h"
> +#include "test_progs.h"
> +#include "test_xdp_vlan.skel.h"
> +
> +
> +#define VETH_NAME	"veth0"
> +#define NS_MAX_SIZE	32
> +#define NS1_NAME	"ns-xdp-vlan-1-"
> +#define NS2_NAME	"ns-xdp-vlan-2-"
> +#define NS1_IP_ADDR	"100.64.10.1"
> +#define NS2_IP_ADDR	"100.64.10.2"
> +#define VLAN_ID		4011
> +
> +static int setup_network(char *ns1, char *ns2)
> +{
> +	if (!ASSERT_OK(append_tid(ns1, NS_MAX_SIZE), "create ns1 name"))
> +		goto fail;
> +	if (!ASSERT_OK(append_tid(ns2, NS_MAX_SIZE), "create ns2 name"))
> +		goto fail;
> +

[..]

> +	SYS(fail, "ip netns add %s", ns1);
> +	SYS(fail, "ip netns add %s", ns2);

Will replacing these with open_netns work? Or we don't setup up enough
state to cooperate with 'ip' tool? (same for cleanup_network if it
works)

> +	SYS(fail, "ip -n %s link add %s type veth peer name %s netns %s",
> +	    ns1, VETH_NAME, VETH_NAME, ns2);
> +
> +	/* NOTICE: XDP require VLAN header inside packet payload
> +	 *  - Thus, disable VLAN offloading driver features
> +	 */
> +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns1, VETH_NAME);
> +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns2, VETH_NAME);
> +
> +	/* NS1 configuration */
> +	SYS(fail, "ip -n %s addr add %s/24 dev %s", ns1, NS1_IP_ADDR, VETH_NAME);
> +	SYS(fail, "ip -n %s link set %s up", ns1, VETH_NAME);
> +
> +	/* NS2 configuration */
> +	SYS(fail, "ip -n %s link add link %s name %s.%d type vlan id %d",
> +	    ns2, VETH_NAME, VETH_NAME, VLAN_ID, VLAN_ID);
> +	SYS(fail, "ip -n %s addr add %s/24 dev %s.%d", ns2, NS2_IP_ADDR, VETH_NAME, VLAN_ID);
> +	SYS(fail, "ip -n %s link set %s up", ns2, VETH_NAME);
> +	SYS(fail, "ip -n %s link set %s.%d up", ns2, VETH_NAME, VLAN_ID);
> +
> +	/* At this point ping should fail because VLAN tags are only used by NS2 */
> +	return !SYS_NOFAIL("ip netns exec %s ping -W 1 -c1 %s", ns2, NS1_IP_ADDR);
> +
> +fail:
> +	return -1;
> +}
> +
> +static void cleanup_network(const char *ns1, const char *ns2)
> +{
> +	SYS_NOFAIL("ip netns del %s", ns1);
> +	SYS_NOFAIL("ip netns del %s", ns2);
> +}
> +
> +static void xdp_vlan(struct bpf_program *xdp, struct bpf_program *tc, u32 flags)
> +{
> +	LIBBPF_OPTS(bpf_tc_hook, tc_hook, .attach_point = BPF_TC_EGRESS);
> +	LIBBPF_OPTS(bpf_tc_opts, tc_opts, .handle = 1, .priority = 1);
> +	char ns1[NS_MAX_SIZE] = NS1_NAME;
> +	char ns2[NS_MAX_SIZE] = NS2_NAME;
> +	struct nstoken *nstoken = NULL;
> +	int interface;
> +	int ret;
> +
> +	if (!ASSERT_OK(setup_network(ns1, ns2), "setup network"))
> +		goto cleanup;
> +
> +	nstoken = open_netns(ns1);
> +	if (!ASSERT_OK_PTR(nstoken, "open NS1"))
> +		goto cleanup;
> +
> +	interface = if_nametoindex(VETH_NAME);
> +	if (!ASSERT_NEQ(interface, 0, "get interface index"))
> +		goto cleanup;
> +
> +	ret = bpf_xdp_attach(interface, bpf_program__fd(xdp), flags, NULL);
> +	if (!ASSERT_OK(ret, "attach xdp_vlan_change"))
> +		goto cleanup;
> +
> +	tc_hook.ifindex = interface;
> +	ret = bpf_tc_hook_create(&tc_hook);
> +	if (!ASSERT_OK(ret, "bpf_tc_hook_create"))
> +		goto detach_xdp;
> +
> +	/* Now we'll use BPF programs to pop/push the VLAN tags */
> +	tc_opts.prog_fd = bpf_program__fd(tc);
> +	ret = bpf_tc_attach(&tc_hook, &tc_opts);
> +	if (!ASSERT_OK(ret, "bpf_tc_attach"))
> +		goto detach_xdp;
> +
> +	close_netns(nstoken);
> +	nstoken = NULL;
> +
> +	/* Now the namespaces can reach each-other, test with pings */
> +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns1, NS2_IP_ADDR);
> +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns2, NS1_IP_ADDR);
> +
> +
> +detach_tc:
> +	bpf_tc_detach(&tc_hook, &tc_opts);
> +detach_xdp:
> +	bpf_xdp_detach(interface, flags, NULL);
> +cleanup:
> +	close_netns(nstoken);
> +	cleanup_network(ns1, ns2);
> +}
> +
> +/* First test: Remove VLAN by setting VLAN ID 0, using "xdp_vlan_change"
> + * egress use TC to add back VLAN tag 4011
> + */
> +void test_xdp_vlan_change(void)
> +{
> +	struct test_xdp_vlan *skel;
> +
> +	skel = test_xdp_vlan__open_and_load();
> +	if (!ASSERT_OK_PTR(skel, "xdp_vlan__open_and_load"))
> +		return;
> +

[..]

> +	if (test__start_subtest("0"))
> +		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push, 0);

Does the original test also test with flags=0? What is the purpose?

Hi Stanislav,

On 2/21/25 5:14 PM, Stanislav Fomichev wrote:
> On 02/21, Bastien Curutchet (eBPF Foundation) wrote:
>> test_xdp_vlan.sh isn't used by the BPF CI.
>>
>> Migrate test_xdp_vlan.sh in prog_tests/xdp_vlan.c.
>> It uses the same BPF programs located in progs/test_xdp_vlan.c and the
>> same network topology.
>> Remove test_xdp_vlan*.sh and their Makefile entries.
>>
>> Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
>> ---
>>   tools/testing/selftests/bpf/Makefile               |   4 +-
>>   tools/testing/selftests/bpf/prog_tests/xdp_vlan.c  | 175 ++++++++++++++++
>>   tools/testing/selftests/bpf/test_xdp_vlan.sh       | 233 ---------------------
>>   .../selftests/bpf/test_xdp_vlan_mode_generic.sh    |   9 -
>>   .../selftests/bpf/test_xdp_vlan_mode_native.sh     |   9 -
>>   5 files changed, 176 insertions(+), 254 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
>> index 5dc9c84ed30f6e5a46572a9e428f692a79623469..09c1f731b8280696c729e3c87020ef749fee9dcb 100644
>> --- a/tools/testing/selftests/bpf/Makefile
>> +++ b/tools/testing/selftests/bpf/Makefile
>> @@ -103,8 +103,6 @@ TEST_PROGS := test_kmod.sh \
>>   	test_tunnel.sh \
>>   	test_lwt_seg6local.sh \
>>   	test_lirc_mode2.sh \
>> -	test_xdp_vlan_mode_generic.sh \
>> -	test_xdp_vlan_mode_native.sh \
>>   	test_lwt_ip_encap.sh \
>>   	test_tc_tunnel.sh \
>>   	test_tc_edt.sh \
>> @@ -118,7 +116,7 @@ TEST_PROGS := test_kmod.sh \
>>   
>>   TEST_PROGS_EXTENDED := \
>>   	ima_setup.sh verify_sig_setup.sh \
>> -	test_xdp_vlan.sh test_bpftool.py
>> +	test_bpftool.py
>>   
>>   TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
>>   	bpf_test_modorder_y.ko
>> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..18dd25344de768aa83a162a0c091f28a4e5f505e
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
>> @@ -0,0 +1,175 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +/*
>> + * Network topology:
>> + *  -----------        -----------
>> + *  |  NS1    |        |   NS2   |
>> + *  | veth0  -|--------|- veth0  |
>> + *  -----------        -----------
>> + *
>> + */
>> +
>> +#define _GNU_SOURCE
>> +#include <net/if.h>
>> +#include <uapi/linux/if_link.h>
>> +
>> +#include "network_helpers.h"
>> +#include "test_progs.h"
>> +#include "test_xdp_vlan.skel.h"
>> +
>> +
>> +#define VETH_NAME	"veth0"
>> +#define NS_MAX_SIZE	32
>> +#define NS1_NAME	"ns-xdp-vlan-1-"
>> +#define NS2_NAME	"ns-xdp-vlan-2-"
>> +#define NS1_IP_ADDR	"100.64.10.1"
>> +#define NS2_IP_ADDR	"100.64.10.2"
>> +#define VLAN_ID		4011
>> +
>> +static int setup_network(char *ns1, char *ns2)
>> +{
>> +	if (!ASSERT_OK(append_tid(ns1, NS_MAX_SIZE), "create ns1 name"))
>> +		goto fail;
>> +	if (!ASSERT_OK(append_tid(ns2, NS_MAX_SIZE), "create ns2 name"))
>> +		goto fail;
>> +
> 
> [..]
> 
>> +	SYS(fail, "ip netns add %s", ns1);
>> +	SYS(fail, "ip netns add %s", ns2);
> 
> Will replacing these with open_netns work? Or we don't setup up enough
> state to cooperate with 'ip' tool? (same for cleanup_network if it
> works)
> 

Yes, it will work. Initially I planned to use it but it isn't very 
convenient in this case because struct netns_obj is defined in 
test_progs.c, not in the header. This means you can't access ns->nsname 
to get the namespace name and as I use append_tid() this name is 
dynamic. So using netns_new / close_netns / netns_free would require 
keeping both the namespace names (for further ip commands / open_netns) 
and the netns_objs objects (for netns_free) whereas here I only keep the 
namespace name.

I can send a V2 using netns_* helpers if you prefer, though. Maybe I can 
also either move the netns_obj definition in test_progs.h or create a 
'get_nsname()' helper ?

>> +	SYS(fail, "ip -n %s link add %s type veth peer name %s netns %s",
>> +	    ns1, VETH_NAME, VETH_NAME, ns2);
>> +
>> +	/* NOTICE: XDP require VLAN header inside packet payload
>> +	 *  - Thus, disable VLAN offloading driver features
>> +	 */
>> +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns1, VETH_NAME);
>> +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns2, VETH_NAME);
>> +
>> +	/* NS1 configuration */
>> +	SYS(fail, "ip -n %s addr add %s/24 dev %s", ns1, NS1_IP_ADDR, VETH_NAME);
>> +	SYS(fail, "ip -n %s link set %s up", ns1, VETH_NAME);
>> +
>> +	/* NS2 configuration */
>> +	SYS(fail, "ip -n %s link add link %s name %s.%d type vlan id %d",
>> +	    ns2, VETH_NAME, VETH_NAME, VLAN_ID, VLAN_ID);
>> +	SYS(fail, "ip -n %s addr add %s/24 dev %s.%d", ns2, NS2_IP_ADDR, VETH_NAME, VLAN_ID);
>> +	SYS(fail, "ip -n %s link set %s up", ns2, VETH_NAME);
>> +	SYS(fail, "ip -n %s link set %s.%d up", ns2, VETH_NAME, VLAN_ID);
>> +
>> +	/* At this point ping should fail because VLAN tags are only used by NS2 */
>> +	return !SYS_NOFAIL("ip netns exec %s ping -W 1 -c1 %s", ns2, NS1_IP_ADDR);
>> +
>> +fail:
>> +	return -1;
>> +}
>> +
>> +static void cleanup_network(const char *ns1, const char *ns2)
>> +{
>> +	SYS_NOFAIL("ip netns del %s", ns1);
>> +	SYS_NOFAIL("ip netns del %s", ns2);
>> +}
>> +
>> +static void xdp_vlan(struct bpf_program *xdp, struct bpf_program *tc, u32 flags)
>> +{
>> +	LIBBPF_OPTS(bpf_tc_hook, tc_hook, .attach_point = BPF_TC_EGRESS);
>> +	LIBBPF_OPTS(bpf_tc_opts, tc_opts, .handle = 1, .priority = 1);
>> +	char ns1[NS_MAX_SIZE] = NS1_NAME;
>> +	char ns2[NS_MAX_SIZE] = NS2_NAME;
>> +	struct nstoken *nstoken = NULL;
>> +	int interface;
>> +	int ret;
>> +
>> +	if (!ASSERT_OK(setup_network(ns1, ns2), "setup network"))
>> +		goto cleanup;
>> +
>> +	nstoken = open_netns(ns1);
>> +	if (!ASSERT_OK_PTR(nstoken, "open NS1"))
>> +		goto cleanup;
>> +
>> +	interface = if_nametoindex(VETH_NAME);
>> +	if (!ASSERT_NEQ(interface, 0, "get interface index"))
>> +		goto cleanup;
>> +
>> +	ret = bpf_xdp_attach(interface, bpf_program__fd(xdp), flags, NULL);
>> +	if (!ASSERT_OK(ret, "attach xdp_vlan_change"))
>> +		goto cleanup;
>> +
>> +	tc_hook.ifindex = interface;
>> +	ret = bpf_tc_hook_create(&tc_hook);
>> +	if (!ASSERT_OK(ret, "bpf_tc_hook_create"))
>> +		goto detach_xdp;
>> +
>> +	/* Now we'll use BPF programs to pop/push the VLAN tags */
>> +	tc_opts.prog_fd = bpf_program__fd(tc);
>> +	ret = bpf_tc_attach(&tc_hook, &tc_opts);
>> +	if (!ASSERT_OK(ret, "bpf_tc_attach"))
>> +		goto detach_xdp;
>> +
>> +	close_netns(nstoken);
>> +	nstoken = NULL;
>> +
>> +	/* Now the namespaces can reach each-other, test with pings */
>> +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns1, NS2_IP_ADDR);
>> +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns2, NS1_IP_ADDR);
>> +
>> +
>> +detach_tc:
>> +	bpf_tc_detach(&tc_hook, &tc_opts);
>> +detach_xdp:
>> +	bpf_xdp_detach(interface, flags, NULL);
>> +cleanup:
>> +	close_netns(nstoken);
>> +	cleanup_network(ns1, ns2);
>> +}
>> +
>> +/* First test: Remove VLAN by setting VLAN ID 0, using "xdp_vlan_change"
>> + * egress use TC to add back VLAN tag 4011
>> + */
>> +void test_xdp_vlan_change(void)
>> +{
>> +	struct test_xdp_vlan *skel;
>> +
>> +	skel = test_xdp_vlan__open_and_load();
>> +	if (!ASSERT_OK_PTR(skel, "xdp_vlan__open_and_load"))
>> +		return;
>> +
> 
> [..]
> 
>> +	if (test__start_subtest("0"))
>> +		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push, 0);
> 
> Does the original test also test with flags=0? What is the purpose?

The original test allows testing the 'xdp', 'xdpgeneric' and 'xdpdrv' 
modes. My understanding is that flags=0 is the 'xdp' equivalent. IIRC, 
there are fallbacks that will set these flags to SKB or DRV mode at some 
point but, since it's allowed by the bpf_xdp_attach API, I thought it 
was worth testing. This way, if the fallbacks stop working at some 
point, we'll be noticed.

Best regards,
Bastien

On 02/24, Bastien Curutchet wrote:
> Hi Stanislav,
> 
> On 2/21/25 5:14 PM, Stanislav Fomichev wrote:
> > On 02/21, Bastien Curutchet (eBPF Foundation) wrote:
> > > test_xdp_vlan.sh isn't used by the BPF CI.
> > > 
> > > Migrate test_xdp_vlan.sh in prog_tests/xdp_vlan.c.
> > > It uses the same BPF programs located in progs/test_xdp_vlan.c and the
> > > same network topology.
> > > Remove test_xdp_vlan*.sh and their Makefile entries.
> > > 
> > > Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
> > > ---
> > >   tools/testing/selftests/bpf/Makefile               |   4 +-
> > >   tools/testing/selftests/bpf/prog_tests/xdp_vlan.c  | 175 ++++++++++++++++
> > >   tools/testing/selftests/bpf/test_xdp_vlan.sh       | 233 ---------------------
> > >   .../selftests/bpf/test_xdp_vlan_mode_generic.sh    |   9 -
> > >   .../selftests/bpf/test_xdp_vlan_mode_native.sh     |   9 -
> > >   5 files changed, 176 insertions(+), 254 deletions(-)
> > > 
> > > diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> > > index 5dc9c84ed30f6e5a46572a9e428f692a79623469..09c1f731b8280696c729e3c87020ef749fee9dcb 100644
> > > --- a/tools/testing/selftests/bpf/Makefile
> > > +++ b/tools/testing/selftests/bpf/Makefile
> > > @@ -103,8 +103,6 @@ TEST_PROGS := test_kmod.sh \
> > >   	test_tunnel.sh \
> > >   	test_lwt_seg6local.sh \
> > >   	test_lirc_mode2.sh \
> > > -	test_xdp_vlan_mode_generic.sh \
> > > -	test_xdp_vlan_mode_native.sh \
> > >   	test_lwt_ip_encap.sh \
> > >   	test_tc_tunnel.sh \
> > >   	test_tc_edt.sh \
> > > @@ -118,7 +116,7 @@ TEST_PROGS := test_kmod.sh \
> > >   TEST_PROGS_EXTENDED := \
> > >   	ima_setup.sh verify_sig_setup.sh \
> > > -	test_xdp_vlan.sh test_bpftool.py
> > > +	test_bpftool.py
> > >   TEST_KMODS := bpf_testmod.ko bpf_test_no_cfi.ko bpf_test_modorder_x.ko \
> > >   	bpf_test_modorder_y.ko
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
> > > new file mode 100644
> > > index 0000000000000000000000000000000000000000..18dd25344de768aa83a162a0c091f28a4e5f505e
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/prog_tests/xdp_vlan.c
> > > @@ -0,0 +1,175 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +
> > > +/*
> > > + * Network topology:
> > > + *  -----------        -----------
> > > + *  |  NS1    |        |   NS2   |
> > > + *  | veth0  -|--------|- veth0  |
> > > + *  -----------        -----------
> > > + *
> > > + */
> > > +
> > > +#define _GNU_SOURCE
> > > +#include <net/if.h>
> > > +#include <uapi/linux/if_link.h>
> > > +
> > > +#include "network_helpers.h"
> > > +#include "test_progs.h"
> > > +#include "test_xdp_vlan.skel.h"
> > > +
> > > +
> > > +#define VETH_NAME	"veth0"
> > > +#define NS_MAX_SIZE	32
> > > +#define NS1_NAME	"ns-xdp-vlan-1-"
> > > +#define NS2_NAME	"ns-xdp-vlan-2-"
> > > +#define NS1_IP_ADDR	"100.64.10.1"
> > > +#define NS2_IP_ADDR	"100.64.10.2"
> > > +#define VLAN_ID		4011
> > > +
> > > +static int setup_network(char *ns1, char *ns2)
> > > +{
> > > +	if (!ASSERT_OK(append_tid(ns1, NS_MAX_SIZE), "create ns1 name"))
> > > +		goto fail;
> > > +	if (!ASSERT_OK(append_tid(ns2, NS_MAX_SIZE), "create ns2 name"))
> > > +		goto fail;
> > > +
> > 
> > [..]
> > 
> > > +	SYS(fail, "ip netns add %s", ns1);
> > > +	SYS(fail, "ip netns add %s", ns2);
> > 
> > Will replacing these with open_netns work? Or we don't setup up enough
> > state to cooperate with 'ip' tool? (same for cleanup_network if it
> > works)
> > 
> 
> Yes, it will work. Initially I planned to use it but it isn't very
> convenient in this case because struct netns_obj is defined in test_progs.c,
> not in the header. This means you can't access ns->nsname to get the
> namespace name and as I use append_tid() this name is dynamic. So using
> netns_new / close_netns / netns_free would require keeping both the
> namespace names (for further ip commands / open_netns) and the netns_objs
> objects (for netns_free) whereas here I only keep the namespace name.
> 
> I can send a V2 using netns_* helpers if you prefer, though. Maybe I can
> also either move the netns_obj definition in test_progs.h or create a
> 'get_nsname()' helper ?

If it's only gonna complicate the matters let's keep as is. I'm mainly
coming from the position of trying to eliminate external calls (SYS()),
but removing two will not move the needle :-)

> > > +	SYS(fail, "ip -n %s link add %s type veth peer name %s netns %s",
> > > +	    ns1, VETH_NAME, VETH_NAME, ns2);
> > > +
> > > +	/* NOTICE: XDP require VLAN header inside packet payload
> > > +	 *  - Thus, disable VLAN offloading driver features
> > > +	 */
> > > +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns1, VETH_NAME);
> > > +	SYS(fail, "ip netns exec %s ethtool -K %s rxvlan off txvlan off", ns2, VETH_NAME);
> > > +
> > > +	/* NS1 configuration */
> > > +	SYS(fail, "ip -n %s addr add %s/24 dev %s", ns1, NS1_IP_ADDR, VETH_NAME);
> > > +	SYS(fail, "ip -n %s link set %s up", ns1, VETH_NAME);
> > > +
> > > +	/* NS2 configuration */
> > > +	SYS(fail, "ip -n %s link add link %s name %s.%d type vlan id %d",
> > > +	    ns2, VETH_NAME, VETH_NAME, VLAN_ID, VLAN_ID);
> > > +	SYS(fail, "ip -n %s addr add %s/24 dev %s.%d", ns2, NS2_IP_ADDR, VETH_NAME, VLAN_ID);
> > > +	SYS(fail, "ip -n %s link set %s up", ns2, VETH_NAME);
> > > +	SYS(fail, "ip -n %s link set %s.%d up", ns2, VETH_NAME, VLAN_ID);
> > > +
> > > +	/* At this point ping should fail because VLAN tags are only used by NS2 */
> > > +	return !SYS_NOFAIL("ip netns exec %s ping -W 1 -c1 %s", ns2, NS1_IP_ADDR);
> > > +
> > > +fail:
> > > +	return -1;
> > > +}
> > > +
> > > +static void cleanup_network(const char *ns1, const char *ns2)
> > > +{
> > > +	SYS_NOFAIL("ip netns del %s", ns1);
> > > +	SYS_NOFAIL("ip netns del %s", ns2);
> > > +}
> > > +
> > > +static void xdp_vlan(struct bpf_program *xdp, struct bpf_program *tc, u32 flags)
> > > +{
> > > +	LIBBPF_OPTS(bpf_tc_hook, tc_hook, .attach_point = BPF_TC_EGRESS);
> > > +	LIBBPF_OPTS(bpf_tc_opts, tc_opts, .handle = 1, .priority = 1);
> > > +	char ns1[NS_MAX_SIZE] = NS1_NAME;
> > > +	char ns2[NS_MAX_SIZE] = NS2_NAME;
> > > +	struct nstoken *nstoken = NULL;
> > > +	int interface;
> > > +	int ret;
> > > +
> > > +	if (!ASSERT_OK(setup_network(ns1, ns2), "setup network"))
> > > +		goto cleanup;
> > > +
> > > +	nstoken = open_netns(ns1);
> > > +	if (!ASSERT_OK_PTR(nstoken, "open NS1"))
> > > +		goto cleanup;
> > > +
> > > +	interface = if_nametoindex(VETH_NAME);
> > > +	if (!ASSERT_NEQ(interface, 0, "get interface index"))
> > > +		goto cleanup;
> > > +
> > > +	ret = bpf_xdp_attach(interface, bpf_program__fd(xdp), flags, NULL);
> > > +	if (!ASSERT_OK(ret, "attach xdp_vlan_change"))
> > > +		goto cleanup;
> > > +
> > > +	tc_hook.ifindex = interface;
> > > +	ret = bpf_tc_hook_create(&tc_hook);
> > > +	if (!ASSERT_OK(ret, "bpf_tc_hook_create"))
> > > +		goto detach_xdp;
> > > +
> > > +	/* Now we'll use BPF programs to pop/push the VLAN tags */
> > > +	tc_opts.prog_fd = bpf_program__fd(tc);
> > > +	ret = bpf_tc_attach(&tc_hook, &tc_opts);
> > > +	if (!ASSERT_OK(ret, "bpf_tc_attach"))
> > > +		goto detach_xdp;
> > > +
> > > +	close_netns(nstoken);
> > > +	nstoken = NULL;
> > > +
> > > +	/* Now the namespaces can reach each-other, test with pings */
> > > +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns1, NS2_IP_ADDR);
> > > +	SYS(detach_tc, "ip netns exec %s ping -i 0.2 -W 2 -c 2 %s > /dev/null", ns2, NS1_IP_ADDR);
> > > +
> > > +
> > > +detach_tc:
> > > +	bpf_tc_detach(&tc_hook, &tc_opts);
> > > +detach_xdp:
> > > +	bpf_xdp_detach(interface, flags, NULL);
> > > +cleanup:
> > > +	close_netns(nstoken);
> > > +	cleanup_network(ns1, ns2);
> > > +}
> > > +
> > > +/* First test: Remove VLAN by setting VLAN ID 0, using "xdp_vlan_change"
> > > + * egress use TC to add back VLAN tag 4011
> > > + */
> > > +void test_xdp_vlan_change(void)
> > > +{
> > > +	struct test_xdp_vlan *skel;
> > > +
> > > +	skel = test_xdp_vlan__open_and_load();
> > > +	if (!ASSERT_OK_PTR(skel, "xdp_vlan__open_and_load"))
> > > +		return;
> > > +
> > 
> > [..]
> > 
> > > +	if (test__start_subtest("0"))
> > > +		xdp_vlan(skel->progs.xdp_vlan_change, skel->progs.tc_vlan_push, 0);
> > 
> > Does the original test also test with flags=0? What is the purpose?
> 
> The original test allows testing the 'xdp', 'xdpgeneric' and 'xdpdrv' modes.
> My understanding is that flags=0 is the 'xdp' equivalent. IIRC, there are
> fallbacks that will set these flags to SKB or DRV mode at some point but,
> since it's allowed by the bpf_xdp_attach API, I thought it was worth
> testing. This way, if the fallbacks stop working at some point, we'll be
> noticed.

Right, it seems like 'xdp' triggers a single 'dev->netdev_ops->ndo_bpf ?
XDP_MODE_DRV : XDP_MODE_SKB' check in dev_xdp_mode. I did miss that the
original test gives you three options, thanks for clarifying!