selftests/bpf: introduce XDP compliance test tool

Introduce xdp_features tool in order to test XDP features supported by
the NIC and match them against advertised ones.
In order to test supported/advertised XDP features, xdp_features must
run on the Device Under Test (DUT) and on a Tester device.
xdp_features opens a control TCP channel between DUT and Tester devices
to send control commands from Tester to the DUT and a UDP data channel
where the Tester sends UDP 'echo' packets and the DUT is expected to
reply back with the same packet. DUT installs multiple XDP programs on the
NIC to test XDP capabilities and reports back to the Tester some XDP stats.
Currently xdp_features supports the following XDP features:
- XDP_DROP
- XDP_ABORTED
- XDP_PASS
- XDP_TX
- XDP_REDIRECT
- XDP_NDO_XMIT

Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/7c1af8e7e6ef0614cf32fa9e6bdaa2d8d605f859.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/.gitignore

@@ -48,3 +48,4 @@ xskxceiver
 xdp_redirect_multi
 xdp_synproxy
 xdp_hw_metadata
+xdp_features

tools/testing/selftests/bpf/Makefile

@@ -73,7 +73,8 @@ TEST_PROGS := test_kmod.sh \
 	test_bpftool.sh \
 	test_bpftool_metadata.sh \
 	test_doc_build.sh \
-	test_xsk.sh
+	test_xsk.sh \
+	test_xdp_features.sh
 
 TEST_PROGS_EXTENDED := with_addr.sh \
 	with_tunnels.sh ima_setup.sh verify_sig_setup.sh \
@@ -83,7 +84,8 @@ TEST_PROGS_EXTENDED := with_addr.sh \
 TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
 	flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
 	test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
-	xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata
+	xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
+	xdp_features
 
 TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read $(OUTPUT)/sign-file
 TEST_GEN_FILES += liburandom_read.so
@@ -385,6 +387,7 @@ test_subskeleton_lib.skel.h-deps := test_subskeleton_lib2.bpf.o test_subskeleton
 test_usdt.skel.h-deps := test_usdt.bpf.o test_usdt_multispec.bpf.o
 xsk_xdp_progs.skel.h-deps := xsk_xdp_progs.bpf.o
 xdp_hw_metadata.skel.h-deps := xdp_hw_metadata.bpf.o
+xdp_features.skel.h-deps := xdp_features.bpf.o
 
 LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
 
@@ -587,6 +590,10 @@ $(OUTPUT)/xdp_hw_metadata: xdp_hw_metadata.c $(OUTPUT)/network_helpers.o $(OUTPU
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
 
+$(OUTPUT)/xdp_features: xdp_features.c $(OUTPUT)/network_helpers.o $(OUTPUT)/xdp_features.skel.h | $(OUTPUT)
+	$(call msg,BINARY,,$@)
+	$(Q)$(CC) $(CFLAGS) $(filter %.a %.o %.c,$^) $(LDLIBS) -o $@
+
 # Make sure we are able to include and link libbpf against c++.
 $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
 	$(call msg,CXX,,$@)

tools/testing/selftests/bpf/progs/xdp_features.c

@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdbool.h>
+#include <linux/bpf.h>
+#include <linux/netdev.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/udp.h>
+#include <asm-generic/errno-base.h>
+
+#include "xdp_features.h"
+
+#define ipv6_addr_equal(a, b)	((a).s6_addr32[0] == (b).s6_addr32[0] &&	\
+				 (a).s6_addr32[1] == (b).s6_addr32[1] &&	\
+				 (a).s6_addr32[2] == (b).s6_addr32[2] &&	\
+				 (a).s6_addr32[3] == (b).s6_addr32[3])
+
+struct net_device;
+struct bpf_prog;
+
+struct xdp_cpumap_stats {
+	unsigned int redirect;
+	unsigned int pass;
+	unsigned int drop;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, __u32);
+	__type(value, __u32);
+	__uint(max_entries, 1);
+} stats SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, __u32);
+	__type(value, __u32);
+	__uint(max_entries, 1);
+} dut_stats SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CPUMAP);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(struct bpf_cpumap_val));
+	__uint(max_entries, 1);
+} cpu_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_DEVMAP);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(struct bpf_devmap_val));
+	__uint(max_entries, 1);
+} dev_map SEC(".maps");
+
+const volatile struct in6_addr tester_addr;
+const volatile struct in6_addr dut_addr;
+
+static __always_inline int
+xdp_process_echo_packet(struct xdp_md *xdp, bool dut)
+{
+	void *data_end = (void *)(long)xdp->data_end;
+	void *data = (void *)(long)xdp->data;
+	struct ethhdr *eh = data;
+	struct tlv_hdr *tlv;
+	struct udphdr *uh;
+	__be16 port;
+	__u8 *cmd;
+
+	if (eh + 1 > (struct ethhdr *)data_end)
+		return -EINVAL;
+
+	if (eh->h_proto == bpf_htons(ETH_P_IP)) {
+		struct iphdr *ih = (struct iphdr *)(eh + 1);
+		__be32 saddr = dut ? tester_addr.s6_addr32[3]
+				   : dut_addr.s6_addr32[3];
+		__be32 daddr = dut ? dut_addr.s6_addr32[3]
+				   : tester_addr.s6_addr32[3];
+
+		ih = (struct iphdr *)(eh + 1);
+		if (ih + 1 > (struct iphdr *)data_end)
+			return -EINVAL;
+
+		if (saddr != ih->saddr)
+			return -EINVAL;
+
+		if (daddr != ih->daddr)
+			return -EINVAL;
+
+		if (ih->protocol != IPPROTO_UDP)
+			return -EINVAL;
+
+		uh = (struct udphdr *)(ih + 1);
+	} else if (eh->h_proto == bpf_htons(ETH_P_IPV6)) {
+		struct in6_addr saddr = dut ? tester_addr : dut_addr;
+		struct in6_addr daddr = dut ? dut_addr : tester_addr;
+		struct ipv6hdr *ih6 = (struct ipv6hdr *)(eh + 1);
+
+		if (ih6 + 1 > (struct ipv6hdr *)data_end)
+			return -EINVAL;
+
+		if (!ipv6_addr_equal(saddr, ih6->saddr))
+			return -EINVAL;
+
+		if (!ipv6_addr_equal(daddr, ih6->daddr))
+			return -EINVAL;
+
+		if (ih6->nexthdr != IPPROTO_UDP)
+			return -EINVAL;
+
+		uh = (struct udphdr *)(ih6 + 1);
+	} else {
+		return -EINVAL;
+	}
+
+	if (uh + 1 > (struct udphdr *)data_end)
+		return -EINVAL;
+
+	port = dut ? uh->dest : uh->source;
+	if (port != bpf_htons(DUT_ECHO_PORT))
+		return -EINVAL;
+
+	tlv = (struct tlv_hdr *)(uh + 1);
+	if (tlv + 1 > data_end)
+		return -EINVAL;
+
+	return bpf_htons(tlv->type) == CMD_ECHO ? 0 : -EINVAL;
+}
+
+static __always_inline int
+xdp_update_stats(struct xdp_md *xdp, bool tx, bool dut)
+{
+	__u32 *val, key = 0;
+
+	if (xdp_process_echo_packet(xdp, tx))
+		return -EINVAL;
+
+	if (dut)
+		val = bpf_map_lookup_elem(&dut_stats, &key);
+	else
+		val = bpf_map_lookup_elem(&stats, &key);
+
+	if (val)
+		__sync_add_and_fetch(val, 1);
+
+	return 0;
+}
+
+/* Tester */
+
+SEC("xdp")
+int xdp_tester_check_tx(struct xdp_md *xdp)
+{
+	xdp_update_stats(xdp, true, false);
+
+	return XDP_PASS;
+}
+
+SEC("xdp")
+int xdp_tester_check_rx(struct xdp_md *xdp)
+{
+	xdp_update_stats(xdp, false, false);
+
+	return XDP_PASS;
+}
+
+/* DUT */
+
+SEC("xdp")
+int xdp_do_pass(struct xdp_md *xdp)
+{
+	xdp_update_stats(xdp, true, true);
+
+	return XDP_PASS;
+}
+
+SEC("xdp")
+int xdp_do_drop(struct xdp_md *xdp)
+{
+	if (xdp_update_stats(xdp, true, true))
+		return XDP_PASS;
+
+	return XDP_DROP;
+}
+
+SEC("xdp")
+int xdp_do_aborted(struct xdp_md *xdp)
+{
+	if (xdp_process_echo_packet(xdp, true))
+		return XDP_PASS;
+
+	return XDP_ABORTED;
+}
+
+SEC("xdp")
+int xdp_do_tx(struct xdp_md *xdp)
+{
+	void *data = (void *)(long)xdp->data;
+	struct ethhdr *eh = data;
+	__u8 tmp_mac[ETH_ALEN];
+
+	if (xdp_update_stats(xdp, true, true))
+		return XDP_PASS;
+
+	__builtin_memcpy(tmp_mac, eh->h_source, ETH_ALEN);
+	__builtin_memcpy(eh->h_source, eh->h_dest, ETH_ALEN);
+	__builtin_memcpy(eh->h_dest, tmp_mac, ETH_ALEN);
+
+	return XDP_TX;
+}
+
+SEC("xdp")
+int xdp_do_redirect(struct xdp_md *xdp)
+{
+	if (xdp_process_echo_packet(xdp, true))
+		return XDP_PASS;
+
+	return bpf_redirect_map(&cpu_map, 0, 0);
+}
+
+SEC("tp_btf/xdp_exception")
+int BPF_PROG(xdp_exception, const struct net_device *dev,
+	     const struct bpf_prog *xdp, __u32 act)
+{
+	__u32 *val, key = 0;
+
+	val = bpf_map_lookup_elem(&dut_stats, &key);
+	if (val)
+		__sync_add_and_fetch(val, 1);
+
+	return 0;
+}
+
+SEC("tp_btf/xdp_cpumap_kthread")
+int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
+	     unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
+{
+	__u32 *val, key = 0;
+
+	val = bpf_map_lookup_elem(&dut_stats, &key);
+	if (val)
+		__sync_add_and_fetch(val, 1);
+
+	return 0;
+}
+
+SEC("xdp/cpumap")
+int xdp_do_redirect_cpumap(struct xdp_md *xdp)
+{
+	void *data = (void *)(long)xdp->data;
+	struct ethhdr *eh = data;
+	__u8 tmp_mac[ETH_ALEN];
+
+	if (xdp_process_echo_packet(xdp, true))
+		return XDP_PASS;
+
+	__builtin_memcpy(tmp_mac, eh->h_source, ETH_ALEN);
+	__builtin_memcpy(eh->h_source, eh->h_dest, ETH_ALEN);
+	__builtin_memcpy(eh->h_dest, tmp_mac, ETH_ALEN);
+
+	return bpf_redirect_map(&dev_map, 0, 0);
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_xdp_features.sh

@@ -0,0 +1,107 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+readonly NS="ns1-$(mktemp -u XXXXXX)"
+readonly V0_IP4=10.10.0.11
+readonly V1_IP4=10.10.0.1
+readonly V0_IP6=2001:db8::11
+readonly V1_IP6=2001:db8::1
+
+ret=1
+
+setup() {
+	{
+		ip netns add ${NS}
+
+		ip link add v1 type veth peer name v0 netns ${NS}
+
+		ip link set v1 up
+		ip addr add $V1_IP4/24 dev v1
+		ip addr add $V1_IP6/64 nodad dev v1
+		ip -n ${NS} link set dev v0 up
+		ip -n ${NS} addr add $V0_IP4/24 dev v0
+		ip -n ${NS} addr add $V0_IP6/64 nodad dev v0
+
+		# Enable XDP mode and disable checksum offload
+		ethtool -K v1 gro on
+		ethtool -K v1 tx-checksumming off
+		ip netns exec ${NS} ethtool -K v0 gro on
+		ip netns exec ${NS} ethtool -K v0 tx-checksumming off
+	} > /dev/null 2>&1
+}
+
+cleanup() {
+	ip link del v1 2> /dev/null
+	ip netns del ${NS} 2> /dev/null
+	[ "$(pidof xdp_features)" = "" ] || kill $(pidof xdp_features) 2> /dev/null
+}
+
+wait_for_dut_server() {
+	while sleep 1; do
+		ss -tlp | grep -q xdp_features
+		[ $? -eq 0 ] && break
+	done
+}
+
+test_xdp_features() {
+	setup
+
+	## XDP_PASS
+	./xdp_features -f XDP_PASS -D $V1_IP6 -T $V0_IP6 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_PASS \
+					   -D $V1_IP6 -C $V1_IP6 \
+					   -T $V0_IP6 v0
+	[ $? -ne 0 ] && exit
+
+	## XDP_DROP
+	./xdp_features -f XDP_DROP -D ::ffff:$V1_IP4 -T ::ffff:$V0_IP4 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_DROP \
+					   -D ::ffff:$V1_IP4 \
+					   -C ::ffff:$V1_IP4 \
+					   -T ::ffff:$V0_IP4 v0
+	[ $? -ne 0 ] && exit
+
+	## XDP_ABORTED
+	./xdp_features -f XDP_ABORTED -D $V1_IP6 -T $V0_IP6 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_ABORTED \
+					   -D $V1_IP6 -C $V1_IP6 \
+					   -T $V0_IP6 v0
+	[ $? -ne 0 ] && exit
+
+	## XDP_TX
+	./xdp_features -f XDP_TX -D ::ffff:$V1_IP4 -T ::ffff:$V0_IP4 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_TX \
+					   -D ::ffff:$V1_IP4 \
+					   -C ::ffff:$V1_IP4 \
+					   -T ::ffff:$V0_IP4 v0
+	[ $? -ne 0 ] && exit
+
+	## XDP_REDIRECT
+	./xdp_features -f XDP_REDIRECT -D $V1_IP6 -T $V0_IP6 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_REDIRECT \
+					   -D $V1_IP6 -C $V1_IP6 \
+					   -T $V0_IP6 v0
+	[ $? -ne 0 ] && exit
+
+	## XDP_NDO_XMIT
+	./xdp_features -f XDP_NDO_XMIT -D ::ffff:$V1_IP4 -T ::ffff:$V0_IP4 v1 &
+	wait_for_dut_server
+	ip netns exec ${NS} ./xdp_features -t -f XDP_NDO_XMIT \
+					   -D ::ffff:$V1_IP4 \
+					   -C ::ffff:$V1_IP4 \
+					   -T ::ffff:$V0_IP4 v0
+	ret=$?
+	cleanup
+}
+
+set -e
+trap cleanup 2 3 6 9
+
+test_xdp_features
+
+exit $ret

tools/testing/selftests/bpf/xdp_features.c

@@ -0,0 +1,699 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/netdev.h>
+#include <linux/if_link.h>
+#include <signal.h>
+#include <argp.h>
+#include <net/if.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include <pthread.h>
+
+#include <network_helpers.h>
+
+#include "xdp_features.skel.h"
+#include "xdp_features.h"
+
+#define RED(str)	"\033[0;31m" str "\033[0m"
+#define GREEN(str)	"\033[0;32m" str "\033[0m"
+#define YELLOW(str)	"\033[0;33m" str "\033[0m"
+
+static struct env {
+	bool verbosity;
+	int ifindex;
+	bool is_tester;
+	struct {
+		enum netdev_xdp_act drv_feature;
+		enum xdp_action action;
+	} feature;
+	struct sockaddr_storage dut_ctrl_addr;
+	struct sockaddr_storage dut_addr;
+	struct sockaddr_storage tester_addr;
+} env;
+
+#define BUFSIZE		128
+
+void test__fail(void) { /* for network_helpers.c */ }
+
+static int libbpf_print_fn(enum libbpf_print_level level,
+			   const char *format, va_list args)
+{
+	if (level == LIBBPF_DEBUG && !env.verbosity)
+		return 0;
+	return vfprintf(stderr, format, args);
+}
+
+static volatile bool exiting;
+
+static void sig_handler(int sig)
+{
+	exiting = true;
+}
+
+const char *argp_program_version = "xdp-features 0.0";
+const char argp_program_doc[] =
+"XDP features detecion application.\n"
+"\n"
+"XDP features application checks the XDP advertised features match detected ones.\n"
+"\n"
+"USAGE: ./xdp-features [-vt] [-f <xdp-feature>] [-D <dut-data-ip>] [-T <tester-data-ip>] [-C <dut-ctrl-ip>] <iface-name>\n"
+"\n"
+"dut-data-ip, tester-data-ip, dut-ctrl-ip: IPv6 or IPv4-mapped-IPv6 addresses;\n"
+"\n"
+"XDP features\n:"
+"- XDP_PASS\n"
+"- XDP_DROP\n"
+"- XDP_ABORTED\n"
+"- XDP_REDIRECT\n"
+"- XDP_NDO_XMIT\n"
+"- XDP_TX\n";
+
+static const struct argp_option opts[] = {
+	{ "verbose", 'v', NULL, 0, "Verbose debug output" },
+	{ "tester", 't', NULL, 0, "Tester mode" },
+	{ "feature", 'f', "XDP-FEATURE", 0, "XDP feature to test" },
+	{ "dut_data_ip", 'D', "DUT-DATA-IP", 0, "DUT IP data channel" },
+	{ "dut_ctrl_ip", 'C', "DUT-CTRL-IP", 0, "DUT IP control channel" },
+	{ "tester_data_ip", 'T', "TESTER-DATA-IP", 0, "Tester IP data channel" },
+	{},
+};
+
+static int get_xdp_feature(const char *arg)
+{
+	if (!strcmp(arg, "XDP_PASS")) {
+		env.feature.action = XDP_PASS;
+		env.feature.drv_feature = NETDEV_XDP_ACT_BASIC;
+	} else if (!strcmp(arg, "XDP_DROP")) {
+		env.feature.drv_feature = NETDEV_XDP_ACT_BASIC;
+		env.feature.action = XDP_DROP;
+	} else if (!strcmp(arg, "XDP_ABORTED")) {
+		env.feature.drv_feature = NETDEV_XDP_ACT_BASIC;
+		env.feature.action = XDP_ABORTED;
+	} else if (!strcmp(arg, "XDP_TX")) {
+		env.feature.drv_feature = NETDEV_XDP_ACT_BASIC;
+		env.feature.action = XDP_TX;
+	} else if (!strcmp(arg, "XDP_REDIRECT")) {
+		env.feature.drv_feature = NETDEV_XDP_ACT_REDIRECT;
+		env.feature.action = XDP_REDIRECT;
+	} else if (!strcmp(arg, "XDP_NDO_XMIT")) {
+		env.feature.drv_feature = NETDEV_XDP_ACT_NDO_XMIT;
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static char *get_xdp_feature_str(void)
+{
+	switch (env.feature.action) {
+	case XDP_PASS:
+		return YELLOW("XDP_PASS");
+	case XDP_DROP:
+		return YELLOW("XDP_DROP");
+	case XDP_ABORTED:
+		return YELLOW("XDP_ABORTED");
+	case XDP_TX:
+		return YELLOW("XDP_TX");
+	case XDP_REDIRECT:
+		return YELLOW("XDP_REDIRECT");
+	default:
+		break;
+	}
+
+	if (env.feature.drv_feature == NETDEV_XDP_ACT_NDO_XMIT)
+		return YELLOW("XDP_NDO_XMIT");
+
+	return "";
+}
+
+static error_t parse_arg(int key, char *arg, struct argp_state *state)
+{
+	switch (key) {
+	case 'v':
+		env.verbosity = true;
+		break;
+	case 't':
+		env.is_tester = true;
+		break;
+	case 'f':
+		if (get_xdp_feature(arg) < 0) {
+			fprintf(stderr, "Invalid xdp feature: %s\n", arg);
+			argp_usage(state);
+			return ARGP_ERR_UNKNOWN;
+		}
+		break;
+	case 'D':
+		if (make_sockaddr(AF_INET6, arg, DUT_ECHO_PORT,
+				  &env.dut_addr, NULL)) {
+			fprintf(stderr, "Invalid DUT address: %s\n", arg);
+			return ARGP_ERR_UNKNOWN;
+		}
+		break;
+	case 'C':
+		if (make_sockaddr(AF_INET6, arg, DUT_CTRL_PORT,
+				  &env.dut_ctrl_addr, NULL)) {
+			fprintf(stderr, "Invalid DUT CTRL address: %s\n", arg);
+			return ARGP_ERR_UNKNOWN;
+		}
+		break;
+	case 'T':
+		if (make_sockaddr(AF_INET6, arg, 0, &env.tester_addr, NULL)) {
+			fprintf(stderr, "Invalid Tester address: %s\n", arg);
+			return ARGP_ERR_UNKNOWN;
+		}
+		break;
+	case ARGP_KEY_ARG:
+		errno = 0;
+		if (strlen(arg) >= IF_NAMESIZE) {
+			fprintf(stderr, "Invalid device name: %s\n", arg);
+			argp_usage(state);
+			return ARGP_ERR_UNKNOWN;
+		}
+
+		env.ifindex = if_nametoindex(arg);
+		if (!env.ifindex)
+			env.ifindex = strtoul(arg, NULL, 0);
+		if (!env.ifindex) {
+			fprintf(stderr,
+				"Bad interface index or name (%d): %s\n",
+				errno, strerror(errno));
+			argp_usage(state);
+			return ARGP_ERR_UNKNOWN;
+		}
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+
+	return 0;
+}
+
+static const struct argp argp = {
+	.options = opts,
+	.parser = parse_arg,
+	.doc = argp_program_doc,
+};
+
+static void set_env_default(void)
+{
+	env.feature.drv_feature = NETDEV_XDP_ACT_NDO_XMIT;
+	env.feature.action = -EINVAL;
+	env.ifindex = -ENODEV;
+	make_sockaddr(AF_INET6, "::ffff:127.0.0.1", DUT_CTRL_PORT,
+		      &env.dut_ctrl_addr, NULL);
+	make_sockaddr(AF_INET6, "::ffff:127.0.0.1", DUT_ECHO_PORT,
+		      &env.dut_addr, NULL);
+	make_sockaddr(AF_INET6, "::ffff:127.0.0.1", 0, &env.tester_addr, NULL);
+}
+
+static void *dut_echo_thread(void *arg)
+{
+	unsigned char buf[sizeof(struct tlv_hdr)];
+	int sockfd = *(int *)arg;
+
+	while (!exiting) {
+		struct tlv_hdr *tlv = (struct tlv_hdr *)buf;
+		struct sockaddr_storage addr;
+		socklen_t addrlen;
+		size_t n;
+
+		n = recvfrom(sockfd, buf, sizeof(buf), MSG_WAITALL,
+			     (struct sockaddr *)&addr, &addrlen);
+		if (n != ntohs(tlv->len))
+			continue;
+
+		if (ntohs(tlv->type) != CMD_ECHO)
+			continue;
+
+		sendto(sockfd, buf, sizeof(buf), MSG_NOSIGNAL | MSG_CONFIRM,
+		       (struct sockaddr *)&addr, addrlen);
+	}
+
+	pthread_exit((void *)0);
+	close(sockfd);
+
+	return NULL;
+}
+
+static int dut_run_echo_thread(pthread_t *t, int *sockfd)
+{
+	int err;
+
+	sockfd = start_reuseport_server(AF_INET6, SOCK_DGRAM, NULL,
+					DUT_ECHO_PORT, 0, 1);
+	if (!sockfd) {
+		fprintf(stderr, "Failed to create echo socket\n");
+		return -errno;
+	}
+
+	/* start echo channel */
+	err = pthread_create(t, NULL, dut_echo_thread, sockfd);
+	if (err) {
+		fprintf(stderr, "Failed creating dut_echo thread: %s\n",
+			strerror(-err));
+		free_fds(sockfd, 1);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int dut_attach_xdp_prog(struct xdp_features *skel, int flags)
+{
+	enum xdp_action action = env.feature.action;
+	struct bpf_program *prog;
+	unsigned int key = 0;
+	int err, fd = 0;
+
+	if (env.feature.drv_feature == NETDEV_XDP_ACT_NDO_XMIT) {
+		struct bpf_devmap_val entry = {
+			.ifindex = env.ifindex,
+		};
+
+		err = bpf_map__update_elem(skel->maps.dev_map,
+					   &key, sizeof(key),
+					   &entry, sizeof(entry), 0);
+		if (err < 0)
+			return err;
+
+		fd = bpf_program__fd(skel->progs.xdp_do_redirect_cpumap);
+		action = XDP_REDIRECT;
+	}
+
+	switch (action) {
+	case XDP_TX:
+		prog = skel->progs.xdp_do_tx;
+		break;
+	case XDP_DROP:
+		prog = skel->progs.xdp_do_drop;
+		break;
+	case XDP_ABORTED:
+		prog = skel->progs.xdp_do_aborted;
+		break;
+	case XDP_PASS:
+		prog = skel->progs.xdp_do_pass;
+		break;
+	case XDP_REDIRECT: {
+		struct bpf_cpumap_val entry = {
+			.qsize = 2048,
+			.bpf_prog.fd = fd,
+		};
+
+		err = bpf_map__update_elem(skel->maps.cpu_map,
+					   &key, sizeof(key),
+					   &entry, sizeof(entry), 0);
+		if (err < 0)
+			return err;
+
+		prog = skel->progs.xdp_do_redirect;
+		break;
+	}
+	default:
+		return -EINVAL;
+	}
+
+	err = bpf_xdp_attach(env.ifindex, bpf_program__fd(prog), flags, NULL);
+	if (err)
+		fprintf(stderr,
+			"Failed to attach XDP program to ifindex %d\n",
+			env.ifindex);
+	return err;
+}
+
+static int recv_msg(int sockfd, void *buf, size_t bufsize, void *val,
+		    size_t val_size)
+{
+	struct tlv_hdr *tlv = (struct tlv_hdr *)buf;
+	size_t len;
+
+	len = recv(sockfd, buf, bufsize, 0);
+	if (len != ntohs(tlv->len) || len < sizeof(*tlv))
+		return -EINVAL;
+
+	if (val) {
+		len -= sizeof(*tlv);
+		if (len > val_size)
+			return -ENOMEM;
+
+		memcpy(val, tlv->data, len);
+	}
+
+	return 0;
+}
+
+static int dut_run(struct xdp_features *skel)
+{
+	int flags = XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_DRV_MODE;
+	int state, err, *sockfd, ctrl_sockfd, echo_sockfd;
+	struct sockaddr_storage ctrl_addr;
+	pthread_t dut_thread;
+	socklen_t addrlen;
+
+	sockfd = start_reuseport_server(AF_INET6, SOCK_STREAM, NULL,
+					DUT_CTRL_PORT, 0, 1);
+	if (!sockfd) {
+		fprintf(stderr, "Failed to create DUT socket\n");
+		return -errno;
+	}
+
+	ctrl_sockfd = accept(*sockfd, (struct sockaddr *)&ctrl_addr, &addrlen);
+	if (ctrl_sockfd < 0) {
+		fprintf(stderr, "Failed to accept connection on DUT socket\n");
+		free_fds(sockfd, 1);
+		return -errno;
+	}
+
+	/* CTRL loop */
+	while (!exiting) {
+		unsigned char buf[BUFSIZE] = {};
+		struct tlv_hdr *tlv = (struct tlv_hdr *)buf;
+
+		err = recv_msg(ctrl_sockfd, buf, BUFSIZE, NULL, 0);
+		if (err)
+			continue;
+
+		switch (ntohs(tlv->type)) {
+		case CMD_START: {
+			if (state == CMD_START)
+				continue;
+
+			state = CMD_START;
+			/* Load the XDP program on the DUT */
+			err = dut_attach_xdp_prog(skel, flags);
+			if (err)
+				goto out;
+
+			err = dut_run_echo_thread(&dut_thread, &echo_sockfd);
+			if (err < 0)
+				goto out;
+
+			tlv->type = htons(CMD_ACK);
+			tlv->len = htons(sizeof(*tlv));
+			err = send(ctrl_sockfd, buf, sizeof(*tlv), 0);
+			if (err < 0)
+				goto end_thread;
+			break;
+		}
+		case CMD_STOP:
+			if (state != CMD_START)
+				break;
+
+			state = CMD_STOP;
+
+			exiting = true;
+			bpf_xdp_detach(env.ifindex, flags, NULL);
+
+			tlv->type = htons(CMD_ACK);
+			tlv->len = htons(sizeof(*tlv));
+			err = send(ctrl_sockfd, buf, sizeof(*tlv), 0);
+			goto end_thread;
+		case CMD_GET_XDP_CAP: {
+			LIBBPF_OPTS(bpf_xdp_query_opts, opts);
+			unsigned long long val;
+			size_t n;
+
+			err = bpf_xdp_query(env.ifindex, XDP_FLAGS_DRV_MODE,
+					    &opts);
+			if (err) {
+				fprintf(stderr,
+					"Failed to query XDP cap for ifindex %d\n",
+					env.ifindex);
+				goto end_thread;
+			}
+
+			tlv->type = htons(CMD_ACK);
+			n = sizeof(*tlv) + sizeof(opts.feature_flags);
+			tlv->len = htons(n);
+
+			val = htobe64(opts.feature_flags);
+			memcpy(tlv->data, &val, sizeof(val));
+
+			err = send(ctrl_sockfd, buf, n, 0);
+			if (err < 0)
+				goto end_thread;
+			break;
+		}
+		case CMD_GET_STATS: {
+			unsigned int key = 0, val;
+			size_t n;
+
+			err = bpf_map__lookup_elem(skel->maps.dut_stats,
+						   &key, sizeof(key),
+						   &val, sizeof(val), 0);
+			if (err) {
+				fprintf(stderr, "bpf_map_lookup_elem failed\n");
+				goto end_thread;
+			}
+
+			tlv->type = htons(CMD_ACK);
+			n = sizeof(*tlv) + sizeof(val);
+			tlv->len = htons(n);
+
+			val = htonl(val);
+			memcpy(tlv->data, &val, sizeof(val));
+
+			err = send(ctrl_sockfd, buf, n, 0);
+			if (err < 0)
+				goto end_thread;
+			break;
+		}
+		default:
+			break;
+		}
+	}
+
+end_thread:
+	pthread_join(dut_thread, NULL);
+out:
+	bpf_xdp_detach(env.ifindex, flags, NULL);
+	close(ctrl_sockfd);
+	free_fds(sockfd, 1);
+
+	return err;
+}
+
+static bool tester_collect_detected_cap(struct xdp_features *skel,
+					unsigned int dut_stats)
+{
+	unsigned int err, key = 0, val;
+
+	if (!dut_stats)
+		return false;
+
+	err = bpf_map__lookup_elem(skel->maps.stats, &key, sizeof(key),
+				   &val, sizeof(val), 0);
+	if (err) {
+		fprintf(stderr, "bpf_map_lookup_elem failed\n");
+		return false;
+	}
+
+	switch (env.feature.action) {
+	case XDP_PASS:
+	case XDP_TX:
+	case XDP_REDIRECT:
+		return val > 0;
+	case XDP_DROP:
+	case XDP_ABORTED:
+		return val == 0;
+	default:
+		break;
+	}
+
+	if (env.feature.drv_feature == NETDEV_XDP_ACT_NDO_XMIT)
+		return val > 0;
+
+	return false;
+}
+
+static int send_and_recv_msg(int sockfd, enum test_commands cmd, void *val,
+			     size_t val_size)
+{
+	unsigned char buf[BUFSIZE] = {};
+	struct tlv_hdr *tlv = (struct tlv_hdr *)buf;
+	int err;
+
+	tlv->type = htons(cmd);
+	tlv->len = htons(sizeof(*tlv));
+
+	err = send(sockfd, buf, sizeof(*tlv), 0);
+	if (err < 0)
+		return err;
+
+	err = recv_msg(sockfd, buf, BUFSIZE, val, val_size);
+	if (err < 0)
+		return err;
+
+	return ntohs(tlv->type) == CMD_ACK ? 0 : -EINVAL;
+}
+
+static int send_echo_msg(void)
+{
+	unsigned char buf[sizeof(struct tlv_hdr)];
+	struct tlv_hdr *tlv = (struct tlv_hdr *)buf;
+	int sockfd, n;
+
+	sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (sockfd < 0) {
+		fprintf(stderr, "Failed to create echo socket\n");
+		return -errno;
+	}
+
+	tlv->type = htons(CMD_ECHO);
+	tlv->len = htons(sizeof(*tlv));
+
+	n = sendto(sockfd, buf, sizeof(*tlv), MSG_NOSIGNAL | MSG_CONFIRM,
+		   (struct sockaddr *)&env.dut_addr, sizeof(env.dut_addr));
+	close(sockfd);
+
+	return n == ntohs(tlv->len) ? 0 : -EINVAL;
+}
+
+static int tester_run(struct xdp_features *skel)
+{
+	int flags = XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_DRV_MODE;
+	unsigned long long advertised_feature;
+	struct bpf_program *prog;
+	unsigned int stats;
+	int i, err, sockfd;
+	bool detected_cap;
+
+	sockfd = socket(AF_INET6, SOCK_STREAM, 0);
+	if (sockfd < 0) {
+		fprintf(stderr, "Failed to create tester socket\n");
+		return -errno;
+	}
+
+	if (settimeo(sockfd, 1000) < 0)
+		return -EINVAL;
+
+	err = connect(sockfd, (struct sockaddr *)&env.dut_ctrl_addr,
+		      sizeof(env.dut_ctrl_addr));
+	if (err) {
+		fprintf(stderr, "Failed to connect to the DUT\n");
+		return -errno;
+	}
+
+	err = send_and_recv_msg(sockfd, CMD_GET_XDP_CAP, &advertised_feature,
+				sizeof(advertised_feature));
+	if (err < 0) {
+		close(sockfd);
+		return err;
+	}
+
+	advertised_feature = be64toh(advertised_feature);
+
+	if (env.feature.drv_feature == NETDEV_XDP_ACT_NDO_XMIT ||
+	    env.feature.action == XDP_TX)
+		prog = skel->progs.xdp_tester_check_tx;
+	else
+		prog = skel->progs.xdp_tester_check_rx;
+
+	err = bpf_xdp_attach(env.ifindex, bpf_program__fd(prog), flags, NULL);
+	if (err) {
+		fprintf(stderr, "Failed to attach XDP program to ifindex %d\n",
+			env.ifindex);
+		goto out;
+	}
+
+	err = send_and_recv_msg(sockfd, CMD_START, NULL, 0);
+	if (err)
+		goto out;
+
+	for (i = 0; i < 10 && !exiting; i++) {
+		err = send_echo_msg();
+		if (err < 0)
+			goto out;
+
+		sleep(1);
+	}
+
+	err = send_and_recv_msg(sockfd, CMD_GET_STATS, &stats, sizeof(stats));
+	if (err)
+		goto out;
+
+	/* stop the test */
+	err = send_and_recv_msg(sockfd, CMD_STOP, NULL, 0);
+	/* send a new echo message to wake echo thread of the dut */
+	send_echo_msg();
+
+	detected_cap = tester_collect_detected_cap(skel, ntohl(stats));
+
+	fprintf(stdout, "Feature %s: [%s][%s]\n", get_xdp_feature_str(),
+		detected_cap ? GREEN("DETECTED") : RED("NOT DETECTED"),
+		env.feature.drv_feature & advertised_feature ? GREEN("ADVERTISED")
+							     : RED("NOT ADVERTISED"));
+out:
+	bpf_xdp_detach(env.ifindex, flags, NULL);
+	close(sockfd);
+	return err < 0 ? err : 0;
+}
+
+int main(int argc, char **argv)
+{
+	struct xdp_features *skel;
+	int err;
+
+	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
+	libbpf_set_print(libbpf_print_fn);
+
+	signal(SIGINT, sig_handler);
+	signal(SIGTERM, sig_handler);
+
+	set_env_default();
+
+	/* Parse command line arguments */
+	err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
+	if (err)
+		return err;
+
+	if (env.ifindex < 0) {
+		fprintf(stderr, "Invalid ifindex\n");
+		return -ENODEV;
+	}
+
+	/* Load and verify BPF application */
+	skel = xdp_features__open();
+	if (!skel) {
+		fprintf(stderr, "Failed to open and load BPF skeleton\n");
+		return -EINVAL;
+	}
+
+	skel->rodata->tester_addr =
+		((struct sockaddr_in6 *)&env.tester_addr)->sin6_addr;
+	skel->rodata->dut_addr =
+		((struct sockaddr_in6 *)&env.dut_addr)->sin6_addr;
+
+	/* Load & verify BPF programs */
+	err = xdp_features__load(skel);
+	if (err) {
+		fprintf(stderr, "Failed to load and verify BPF skeleton\n");
+		goto cleanup;
+	}
+
+	err = xdp_features__attach(skel);
+	if (err) {
+		fprintf(stderr, "Failed to attach BPF skeleton\n");
+		goto cleanup;
+	}
+
+	if (env.is_tester) {
+		/* Tester */
+		fprintf(stdout, "Starting tester on device %d\n", env.ifindex);
+		err = tester_run(skel);
+	} else {
+		/* DUT */
+		fprintf(stdout, "Starting DUT on device %d\n", env.ifindex);
+		err = dut_run(skel);
+	}
+
+cleanup:
+	xdp_features__destroy(skel);
+
+	return err < 0 ? -err : 0;
+}

tools/testing/selftests/bpf/xdp_features.h

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* test commands */
+enum test_commands {
+	CMD_STOP,		/* CMD */
+	CMD_START,		/* CMD */
+	CMD_ECHO,		/* CMD */
+	CMD_ACK,		/* CMD + data */
+	CMD_GET_XDP_CAP,	/* CMD */
+	CMD_GET_STATS,		/* CMD */
+};
+
+#define DUT_CTRL_PORT	12345
+#define DUT_ECHO_PORT	12346
+
+struct tlv_hdr {
+	__be16 type;
+	__be16 len;
+	__u8 data[];
+};