Merge branch 'Follow-up BPF helper improvements'

Daniel Borkmann says:

====================

This series addresses most of the feedback [0] that was to be followed
up from the last series, that is, UAPI helper comment improvements and
getting rid of the ifindex obj file hacks in the selftest by using a
BPF map instead. The __sk_buff data/data_end pointer work, I'm planning
to do in a later round as well as the mem*() BPF improvements we have
in Cilium for libbpf. Next, the series adds two features, i) a helper
called redirect_peer() to improve latency on netns switch, and ii) to
allow map in map with dynamic inner array map sizes. Selftests for each
are added as well. For details, please check individual patches, thanks!

  [0] https://lore.kernel.org/bpf/cover.1601477936.git.daniel@iogearbox.net/

v5 -> v6:
  - Going with Andrii's suggestion to make the misconfigured verifier
    test more robust, and only probe on -EOPNOTSUPP (Andrii)
v4 -> v5:
  - Replace cnt == -EOPNOTSUPP check with cnt < 0; I've used < 0
    here as I think it's useful to keep the existing cnt == 0 ||
    cnt >= ARRAY_SIZE(insn_buf) for error detection (Andrii)
v3 -> v4:
  - Rename new array map flag to BPF_F_INNER_MAP (Alexei)
v2 -> v3:
  - Remove tab that slipped into uapi helper desc (Jakub)
  - Rework map in map for array to error from map_gen_lookup (Andrii)
v1 -> v2:
  - Fixed selftest comment wrt inner1/inner2 value (Yonghong)
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

6 files changed, 343 insertions, 196 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
index 540fea4c91a5..76ebe4c250f1 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c
@@ -55,10 +55,10 @@ static int kern_sync_rcu(void)
 
 static void test_lookup_update(void)
 {
-	int err, key = 0, val, i;
+	int map1_fd, map2_fd, map3_fd, map4_fd, map5_fd, map1_id, map2_id;
+	int outer_arr_fd, outer_hash_fd, outer_arr_dyn_fd;
 	struct test_btf_map_in_map *skel;
-	int outer_arr_fd, outer_hash_fd;
-	int fd, map1_fd, map2_fd, map1_id, map2_id;
+	int err, key = 0, val, i, fd;
 
 	skel = test_btf_map_in_map__open_and_load();
 	if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n"))
@@ -70,32 +70,45 @@ static void test_lookup_update(void)
 
 	map1_fd = bpf_map__fd(skel->maps.inner_map1);
 	map2_fd = bpf_map__fd(skel->maps.inner_map2);
+	map3_fd = bpf_map__fd(skel->maps.inner_map3);
+	map4_fd = bpf_map__fd(skel->maps.inner_map4);
+	map5_fd = bpf_map__fd(skel->maps.inner_map5);
+	outer_arr_dyn_fd = bpf_map__fd(skel->maps.outer_arr_dyn);
 	outer_arr_fd = bpf_map__fd(skel->maps.outer_arr);
 	outer_hash_fd = bpf_map__fd(skel->maps.outer_hash);
 
-	/* inner1 = input, inner2 = input + 1 */
-	map1_fd = bpf_map__fd(skel->maps.inner_map1);
+	/* inner1 = input, inner2 = input + 1, inner3 = input + 2 */
 	bpf_map_update_elem(outer_arr_fd, &key, &map1_fd, 0);
-	map2_fd = bpf_map__fd(skel->maps.inner_map2);
 	bpf_map_update_elem(outer_hash_fd, &key, &map2_fd, 0);
+	bpf_map_update_elem(outer_arr_dyn_fd, &key, &map3_fd, 0);
 	skel->bss->input = 1;
 	usleep(1);
-
 	bpf_map_lookup_elem(map1_fd, &key, &val);
 	CHECK(val != 1, "inner1", "got %d != exp %d\n", val, 1);
 	bpf_map_lookup_elem(map2_fd, &key, &val);
 	CHECK(val != 2, "inner2", "got %d != exp %d\n", val, 2);
+	bpf_map_lookup_elem(map3_fd, &key, &val);
+	CHECK(val != 3, "inner3", "got %d != exp %d\n", val, 3);
 
-	/* inner1 = input + 1, inner2 = input */
+	/* inner2 = input, inner1 = input + 1, inner4 = input + 2 */
 	bpf_map_update_elem(outer_arr_fd, &key, &map2_fd, 0);
 	bpf_map_update_elem(outer_hash_fd, &key, &map1_fd, 0);
+	bpf_map_update_elem(outer_arr_dyn_fd, &key, &map4_fd, 0);
 	skel->bss->input = 3;
 	usleep(1);
-
 	bpf_map_lookup_elem(map1_fd, &key, &val);
 	CHECK(val != 4, "inner1", "got %d != exp %d\n", val, 4);
 	bpf_map_lookup_elem(map2_fd, &key, &val);
 	CHECK(val != 3, "inner2", "got %d != exp %d\n", val, 3);
+	bpf_map_lookup_elem(map4_fd, &key, &val);
+	CHECK(val != 5, "inner4", "got %d != exp %d\n", val, 5);
+
+	/* inner5 = input + 2 */
+	bpf_map_update_elem(outer_arr_dyn_fd, &key, &map5_fd, 0);
+	skel->bss->input = 5;
+	usleep(1);
+	bpf_map_lookup_elem(map5_fd, &key, &val);
+	CHECK(val != 7, "inner5", "got %d != exp %d\n", val, 7);
 
 	for (i = 0; i < 5; i++) {
 		val = i % 2 ? map1_fd : map2_fd;
@@ -106,7 +119,13 @@ static void test_lookup_update(void)
 		}
 		err = bpf_map_update_elem(outer_arr_fd, &key, &val, 0);
 		if (CHECK_FAIL(err)) {
-			printf("failed to update hash_of_maps on iter #%d\n", i);
+			printf("failed to update array_of_maps on iter #%d\n", i);
+			goto cleanup;
+		}
+		val = i % 2 ? map4_fd : map5_fd;
+		err = bpf_map_update_elem(outer_arr_dyn_fd, &key, &val, 0);
+		if (CHECK_FAIL(err)) {
+			printf("failed to update array_of_maps (dyn) on iter #%d\n", i);
 			goto cleanup;
 		}
 	}
diff --git a/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c b/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c
index 193fe0198b21..c1e0c8c7c55f 100644
--- a/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c
+++ b/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c
@@ -41,6 +41,43 @@ struct outer_arr {
 	.values = { (void *)&inner_map1, 0, (void *)&inner_map2 },
 };
 
+struct inner_map_sz3 {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(map_flags, BPF_F_INNER_MAP);
+	__uint(max_entries, 3);
+	__type(key, int);
+	__type(value, int);
+} inner_map3 SEC(".maps"),
+  inner_map4 SEC(".maps");
+
+struct inner_map_sz4 {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(map_flags, BPF_F_INNER_MAP);
+	__uint(max_entries, 5);
+	__type(key, int);
+	__type(value, int);
+} inner_map5 SEC(".maps");
+
+struct outer_arr_dyn {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__uint(max_entries, 3);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(int));
+	__array(values, struct {
+		__uint(type, BPF_MAP_TYPE_ARRAY);
+		__uint(map_flags, BPF_F_INNER_MAP);
+		__uint(max_entries, 1);
+		__type(key, int);
+		__type(value, int);
+	});
+} outer_arr_dyn SEC(".maps") = {
+	.values = {
+		[0] = (void *)&inner_map3,
+		[1] = (void *)&inner_map4,
+		[2] = (void *)&inner_map5,
+	},
+};
+
 struct outer_hash {
 	__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
 	__uint(max_entries, 5);
@@ -101,6 +138,12 @@ int handle__sys_enter(void *ctx)
 	val = input + 1;
 	bpf_map_update_elem(inner_map, &key, &val, 0);
 
+	inner_map = bpf_map_lookup_elem(&outer_arr_dyn, &key);
+	if (!inner_map)
+		return 1;
+	val = input + 2;
+	bpf_map_update_elem(inner_map, &key, &val, 0);
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/bpf/progs/test_tc_neigh.c b/tools/testing/selftests/bpf/progs/test_tc_neigh.c
index 889a72c3024f..fe182616b112 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_neigh.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_neigh.c
@@ -13,17 +13,10 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
-#ifndef barrier_data
-# define barrier_data(ptr)	asm volatile("": :"r"(ptr) :"memory")
-#endif
-
 #ifndef ctx_ptr
 # define ctx_ptr(field)		(void *)(long)(field)
 #endif
 
-#define dst_to_src_tmp		0xeeddddeeU
-#define src_to_dst_tmp		0xeeffffeeU
-
 #define ip4_src			0xac100164 /* 172.16.1.100 */
 #define ip4_dst			0xac100264 /* 172.16.2.100 */
 
@@ -39,6 +32,18 @@
 				 a.s6_addr32[3] == b.s6_addr32[3])
 #endif
 
+enum {
+	dev_src,
+	dev_dst,
+};
+
+struct bpf_map_def SEC("maps") ifindex_map = {
+	.type		= BPF_MAP_TYPE_ARRAY,
+	.key_size	= sizeof(int),
+	.value_size	= sizeof(int),
+	.max_entries	= 2,
+};
+
 static __always_inline bool is_remote_ep_v4(struct __sk_buff *skb,
 					    __be32 addr)
 {
@@ -73,7 +78,14 @@ static __always_inline bool is_remote_ep_v6(struct __sk_buff *skb,
 	return v6_equal(ip6h->daddr, addr);
 }
 
-SEC("chk_neigh") int tc_chk(struct __sk_buff *skb)
+static __always_inline int get_dev_ifindex(int which)
+{
+	int *ifindex = bpf_map_lookup_elem(&ifindex_map, &which);
+
+	return ifindex ? *ifindex : 0;
+}
+
+SEC("chk_egress") int tc_chk(struct __sk_buff *skb)
 {
 	void *data_end = ctx_ptr(skb->data_end);
 	void *data = ctx_ptr(skb->data);
@@ -87,7 +99,6 @@ SEC("chk_neigh") int tc_chk(struct __sk_buff *skb)
 
 SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
 {
-	int idx = dst_to_src_tmp;
 	__u8 zero[ETH_ALEN * 2];
 	bool redirect = false;
 
@@ -103,19 +114,15 @@ SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
 	if (!redirect)
 		return TC_ACT_OK;
 
-	barrier_data(&idx);
-	idx = bpf_ntohl(idx);
-
 	__builtin_memset(&zero, 0, sizeof(zero));
 	if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
 		return TC_ACT_SHOT;
 
-	return bpf_redirect_neigh(idx, 0);
+	return bpf_redirect_neigh(get_dev_ifindex(dev_src), 0);
 }
 
 SEC("src_ingress") int tc_src(struct __sk_buff *skb)
 {
-	int idx = src_to_dst_tmp;
 	__u8 zero[ETH_ALEN * 2];
 	bool redirect = false;
 
@@ -131,14 +138,11 @@ SEC("src_ingress") int tc_src(struct __sk_buff *skb)
 	if (!redirect)
 		return TC_ACT_OK;
 
-	barrier_data(&idx);
-	idx = bpf_ntohl(idx);
-
 	__builtin_memset(&zero, 0, sizeof(zero));
 	if (bpf_skb_store_bytes(skb, 0, &zero, sizeof(zero), 0) < 0)
 		return TC_ACT_SHOT;
 
-	return bpf_redirect_neigh(idx, 0);
+	return bpf_redirect_neigh(get_dev_ifindex(dev_dst), 0);
 }
 
 char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/test_tc_peer.c b/tools/testing/selftests/bpf/progs/test_tc_peer.c
new file mode 100644
index 000000000000..fc84a7685aa2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_tc_peer.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <linux/bpf.h>
+#include <linux/stddef.h>
+#include <linux/pkt_cls.h>
+
+#include <bpf/bpf_helpers.h>
+
+enum {
+	dev_src,
+	dev_dst,
+};
+
+struct bpf_map_def SEC("maps") ifindex_map = {
+	.type		= BPF_MAP_TYPE_ARRAY,
+	.key_size	= sizeof(int),
+	.value_size	= sizeof(int),
+	.max_entries	= 2,
+};
+
+static __always_inline int get_dev_ifindex(int which)
+{
+	int *ifindex = bpf_map_lookup_elem(&ifindex_map, &which);
+
+	return ifindex ? *ifindex : 0;
+}
+
+SEC("chk_egress") int tc_chk(struct __sk_buff *skb)
+{
+	return TC_ACT_SHOT;
+}
+
+SEC("dst_ingress") int tc_dst(struct __sk_buff *skb)
+{
+	return bpf_redirect_peer(get_dev_ifindex(dev_src), 0);
+}
+
+SEC("src_ingress") int tc_src(struct __sk_buff *skb)
+{
+	return bpf_redirect_peer(get_dev_ifindex(dev_dst), 0);
+}
+
+char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/test_tc_neigh.sh b/tools/testing/selftests/bpf/test_tc_neigh.sh
deleted file mode 100755
index 31d8c3df8b24..000000000000
--- a/tools/testing/selftests/bpf/test_tc_neigh.sh
+++ /dev/null
@@ -1,168 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-#
-# This test sets up 3 netns (src <-> fwd <-> dst). There is no direct veth link
-# between src and dst. The netns fwd has veth links to each src and dst. The
-# client is in src and server in dst. The test installs a TC BPF program to each
-# host facing veth in fwd which calls into bpf_redirect_peer() to perform the
-# neigh addr population and redirect; it also installs a dropper prog on the
-# egress side to drop skbs if neigh addrs were not populated.
-
-if [[ $EUID -ne 0 ]]; then
-	echo "This script must be run as root"
-	echo "FAIL"
-	exit 1
-fi
-
-# check that nc, dd, ping, ping6 and timeout are present
-command -v nc >/dev/null 2>&1 || \
-	{ echo >&2 "nc is not available"; exit 1; }
-command -v dd >/dev/null 2>&1 || \
-	{ echo >&2 "dd is not available"; exit 1; }
-command -v timeout >/dev/null 2>&1 || \
-	{ echo >&2 "timeout is not available"; exit 1; }
-command -v ping >/dev/null 2>&1 || \
-	{ echo >&2 "ping is not available"; exit 1; }
-command -v ping6 >/dev/null 2>&1 || \
-	{ echo >&2 "ping6 is not available"; exit 1; }
-
-readonly GREEN='\033[0;92m'
-readonly RED='\033[0;31m'
-readonly NC='\033[0m' # No Color
-
-readonly PING_ARG="-c 3 -w 10 -q"
-
-readonly TIMEOUT=10
-
-readonly NS_SRC="ns-src-$(mktemp -u XXXXXX)"
-readonly NS_FWD="ns-fwd-$(mktemp -u XXXXXX)"
-readonly NS_DST="ns-dst-$(mktemp -u XXXXXX)"
-
-readonly IP4_SRC="172.16.1.100"
-readonly IP4_DST="172.16.2.100"
-
-readonly IP6_SRC="::1:dead:beef:cafe"
-readonly IP6_DST="::2:dead:beef:cafe"
-
-readonly IP4_SLL="169.254.0.1"
-readonly IP4_DLL="169.254.0.2"
-readonly IP4_NET="169.254.0.0"
-
-cleanup()
-{
-	ip netns del ${NS_SRC}
-	ip netns del ${NS_FWD}
-	ip netns del ${NS_DST}
-}
-
-trap cleanup EXIT
-
-set -e
-
-ip netns add "${NS_SRC}"
-ip netns add "${NS_FWD}"
-ip netns add "${NS_DST}"
-
-ip link add veth_src type veth peer name veth_src_fwd
-ip link add veth_dst type veth peer name veth_dst_fwd
-
-ip link set veth_src netns ${NS_SRC}
-ip link set veth_src_fwd netns ${NS_FWD}
-
-ip link set veth_dst netns ${NS_DST}
-ip link set veth_dst_fwd netns ${NS_FWD}
-
-ip -netns ${NS_SRC} addr add ${IP4_SRC}/32 dev veth_src
-ip -netns ${NS_DST} addr add ${IP4_DST}/32 dev veth_dst
-
-# The fwd netns automatically get a v6 LL address / routes, but also needs v4
-# one in order to start ARP probing. IP4_NET route is added to the endpoints
-# so that the ARP processing will reply.
-
-ip -netns ${NS_FWD} addr add ${IP4_SLL}/32 dev veth_src_fwd
-ip -netns ${NS_FWD} addr add ${IP4_DLL}/32 dev veth_dst_fwd
-
-ip -netns ${NS_SRC} addr add ${IP6_SRC}/128 dev veth_src nodad
-ip -netns ${NS_DST} addr add ${IP6_DST}/128 dev veth_dst nodad
-
-ip -netns ${NS_SRC} link set dev veth_src up
-ip -netns ${NS_FWD} link set dev veth_src_fwd up
-
-ip -netns ${NS_DST} link set dev veth_dst up
-ip -netns ${NS_FWD} link set dev veth_dst_fwd up
-
-ip -netns ${NS_SRC} route add ${IP4_DST}/32 dev veth_src scope global
-ip -netns ${NS_SRC} route add ${IP4_NET}/16 dev veth_src scope global
-ip -netns ${NS_FWD} route add ${IP4_SRC}/32 dev veth_src_fwd scope global
-
-ip -netns ${NS_SRC} route add ${IP6_DST}/128 dev veth_src scope global
-ip -netns ${NS_FWD} route add ${IP6_SRC}/128 dev veth_src_fwd scope global
-
-ip -netns ${NS_DST} route add ${IP4_SRC}/32 dev veth_dst scope global
-ip -netns ${NS_DST} route add ${IP4_NET}/16 dev veth_dst scope global
-ip -netns ${NS_FWD} route add ${IP4_DST}/32 dev veth_dst_fwd scope global
-
-ip -netns ${NS_DST} route add ${IP6_SRC}/128 dev veth_dst scope global
-ip -netns ${NS_FWD} route add ${IP6_DST}/128 dev veth_dst_fwd scope global
-
-fmac_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/address)
-fmac_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/address)
-
-ip -netns ${NS_SRC} neigh add ${IP4_DST} dev veth_src lladdr $fmac_src
-ip -netns ${NS_DST} neigh add ${IP4_SRC} dev veth_dst lladdr $fmac_dst
-
-ip -netns ${NS_SRC} neigh add ${IP6_DST} dev veth_src lladdr $fmac_src
-ip -netns ${NS_DST} neigh add ${IP6_SRC} dev veth_dst lladdr $fmac_dst
-
-veth_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/ifindex | awk '{printf "%08x\n", $1}')
-veth_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/ifindex | awk '{printf "%08x\n", $1}')
-
-xxd -p < test_tc_neigh.o   | sed "s/eeddddee/$veth_src/g" | xxd -r -p > test_tc_neigh.x.o
-xxd -p < test_tc_neigh.x.o | sed "s/eeffffee/$veth_dst/g" | xxd -r -p > test_tc_neigh.y.o
-
-ip netns exec ${NS_FWD} tc qdisc add dev veth_src_fwd clsact
-ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd ingress bpf da obj test_tc_neigh.y.o sec src_ingress
-ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd egress  bpf da obj test_tc_neigh.y.o sec chk_neigh
-
-ip netns exec ${NS_FWD} tc qdisc add dev veth_dst_fwd clsact
-ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd ingress bpf da obj test_tc_neigh.y.o sec dst_ingress
-ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd egress  bpf da obj test_tc_neigh.y.o sec chk_neigh
-
-rm -f test_tc_neigh.x.o test_tc_neigh.y.o
-
-ip netns exec ${NS_DST} bash -c "nc -4 -l -p 9004 &"
-ip netns exec ${NS_DST} bash -c "nc -6 -l -p 9006 &"
-
-set +e
-
-TEST="TCPv4 connectivity test"
-ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP4_DST}/9004"
-if [ $? -ne 0 ]; then
-	echo -e "${TEST}: ${RED}FAIL${NC}"
-	exit 1
-fi
-echo -e "${TEST}: ${GREEN}PASS${NC}"
-
-TEST="TCPv6 connectivity test"
-ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP6_DST}/9006"
-if [ $? -ne 0 ]; then
-	echo -e "${TEST}: ${RED}FAIL${NC}"
-	exit 1
-fi
-echo -e "${TEST}: ${GREEN}PASS${NC}"
-
-TEST="ICMPv4 connectivity test"
-ip netns exec ${NS_SRC} ping  $PING_ARG ${IP4_DST}
-if [ $? -ne 0 ]; then
-	echo -e "${TEST}: ${RED}FAIL${NC}"
-	exit 1
-fi
-echo -e "${TEST}: ${GREEN}PASS${NC}"
-
-TEST="ICMPv6 connectivity test"
-ip netns exec ${NS_SRC} ping6 $PING_ARG ${IP6_DST}
-if [ $? -ne 0 ]; then
-	echo -e "${TEST}: ${RED}FAIL${NC}"
-	exit 1
-fi
-echo -e "${TEST}: ${GREEN}PASS${NC}"
diff --git a/tools/testing/selftests/bpf/test_tc_redirect.sh b/tools/testing/selftests/bpf/test_tc_redirect.sh
new file mode 100755
index 000000000000..6d7482562140
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_tc_redirect.sh
@@ -0,0 +1,204 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# This test sets up 3 netns (src <-> fwd <-> dst). There is no direct veth link
+# between src and dst. The netns fwd has veth links to each src and dst. The
+# client is in src and server in dst. The test installs a TC BPF program to each
+# host facing veth in fwd which calls into i) bpf_redirect_neigh() to perform the
+# neigh addr population and redirect or ii) bpf_redirect_peer() for namespace
+# switch from ingress side; it also installs a checker prog on the egress side
+# to drop unexpected traffic.
+
+if [[ $EUID -ne 0 ]]; then
+	echo "This script must be run as root"
+	echo "FAIL"
+	exit 1
+fi
+
+# check that needed tools are present
+command -v nc >/dev/null 2>&1 || \
+	{ echo >&2 "nc is not available"; exit 1; }
+command -v dd >/dev/null 2>&1 || \
+	{ echo >&2 "dd is not available"; exit 1; }
+command -v timeout >/dev/null 2>&1 || \
+	{ echo >&2 "timeout is not available"; exit 1; }
+command -v ping >/dev/null 2>&1 || \
+	{ echo >&2 "ping is not available"; exit 1; }
+command -v ping6 >/dev/null 2>&1 || \
+	{ echo >&2 "ping6 is not available"; exit 1; }
+command -v perl >/dev/null 2>&1 || \
+	{ echo >&2 "perl is not available"; exit 1; }
+command -v jq >/dev/null 2>&1 || \
+	{ echo >&2 "jq is not available"; exit 1; }
+command -v bpftool >/dev/null 2>&1 || \
+	{ echo >&2 "bpftool is not available"; exit 1; }
+
+readonly GREEN='\033[0;92m'
+readonly RED='\033[0;31m'
+readonly NC='\033[0m' # No Color
+
+readonly PING_ARG="-c 3 -w 10 -q"
+
+readonly TIMEOUT=10
+
+readonly NS_SRC="ns-src-$(mktemp -u XXXXXX)"
+readonly NS_FWD="ns-fwd-$(mktemp -u XXXXXX)"
+readonly NS_DST="ns-dst-$(mktemp -u XXXXXX)"
+
+readonly IP4_SRC="172.16.1.100"
+readonly IP4_DST="172.16.2.100"
+
+readonly IP6_SRC="::1:dead:beef:cafe"
+readonly IP6_DST="::2:dead:beef:cafe"
+
+readonly IP4_SLL="169.254.0.1"
+readonly IP4_DLL="169.254.0.2"
+readonly IP4_NET="169.254.0.0"
+
+netns_cleanup()
+{
+	ip netns del ${NS_SRC}
+	ip netns del ${NS_FWD}
+	ip netns del ${NS_DST}
+}
+
+netns_setup()
+{
+	ip netns add "${NS_SRC}"
+	ip netns add "${NS_FWD}"
+	ip netns add "${NS_DST}"
+
+	ip link add veth_src type veth peer name veth_src_fwd
+	ip link add veth_dst type veth peer name veth_dst_fwd
+
+	ip link set veth_src netns ${NS_SRC}
+	ip link set veth_src_fwd netns ${NS_FWD}
+
+	ip link set veth_dst netns ${NS_DST}
+	ip link set veth_dst_fwd netns ${NS_FWD}
+
+	ip -netns ${NS_SRC} addr add ${IP4_SRC}/32 dev veth_src
+	ip -netns ${NS_DST} addr add ${IP4_DST}/32 dev veth_dst
+
+	# The fwd netns automatically get a v6 LL address / routes, but also
+	# needs v4 one in order to start ARP probing. IP4_NET route is added
+	# to the endpoints so that the ARP processing will reply.
+
+	ip -netns ${NS_FWD} addr add ${IP4_SLL}/32 dev veth_src_fwd
+	ip -netns ${NS_FWD} addr add ${IP4_DLL}/32 dev veth_dst_fwd
+
+	ip -netns ${NS_SRC} addr add ${IP6_SRC}/128 dev veth_src nodad
+	ip -netns ${NS_DST} addr add ${IP6_DST}/128 dev veth_dst nodad
+
+	ip -netns ${NS_SRC} link set dev veth_src up
+	ip -netns ${NS_FWD} link set dev veth_src_fwd up
+
+	ip -netns ${NS_DST} link set dev veth_dst up
+	ip -netns ${NS_FWD} link set dev veth_dst_fwd up
+
+	ip -netns ${NS_SRC} route add ${IP4_DST}/32 dev veth_src scope global
+	ip -netns ${NS_SRC} route add ${IP4_NET}/16 dev veth_src scope global
+	ip -netns ${NS_FWD} route add ${IP4_SRC}/32 dev veth_src_fwd scope global
+
+	ip -netns ${NS_SRC} route add ${IP6_DST}/128 dev veth_src scope global
+	ip -netns ${NS_FWD} route add ${IP6_SRC}/128 dev veth_src_fwd scope global
+
+	ip -netns ${NS_DST} route add ${IP4_SRC}/32 dev veth_dst scope global
+	ip -netns ${NS_DST} route add ${IP4_NET}/16 dev veth_dst scope global
+	ip -netns ${NS_FWD} route add ${IP4_DST}/32 dev veth_dst_fwd scope global
+
+	ip -netns ${NS_DST} route add ${IP6_SRC}/128 dev veth_dst scope global
+	ip -netns ${NS_FWD} route add ${IP6_DST}/128 dev veth_dst_fwd scope global
+
+	fmac_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/address)
+	fmac_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/address)
+
+	ip -netns ${NS_SRC} neigh add ${IP4_DST} dev veth_src lladdr $fmac_src
+	ip -netns ${NS_DST} neigh add ${IP4_SRC} dev veth_dst lladdr $fmac_dst
+
+	ip -netns ${NS_SRC} neigh add ${IP6_DST} dev veth_src lladdr $fmac_src
+	ip -netns ${NS_DST} neigh add ${IP6_SRC} dev veth_dst lladdr $fmac_dst
+}
+
+netns_test_connectivity()
+{
+	set +e
+
+	ip netns exec ${NS_DST} bash -c "nc -4 -l -p 9004 &"
+	ip netns exec ${NS_DST} bash -c "nc -6 -l -p 9006 &"
+
+	TEST="TCPv4 connectivity test"
+	ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP4_DST}/9004"
+	if [ $? -ne 0 ]; then
+		echo -e "${TEST}: ${RED}FAIL${NC}"
+		exit 1
+	fi
+	echo -e "${TEST}: ${GREEN}PASS${NC}"
+
+	TEST="TCPv6 connectivity test"
+	ip netns exec ${NS_SRC} bash -c "timeout ${TIMEOUT} dd if=/dev/zero bs=1000 count=100 > /dev/tcp/${IP6_DST}/9006"
+	if [ $? -ne 0 ]; then
+		echo -e "${TEST}: ${RED}FAIL${NC}"
+		exit 1
+	fi
+	echo -e "${TEST}: ${GREEN}PASS${NC}"
+
+	TEST="ICMPv4 connectivity test"
+	ip netns exec ${NS_SRC} ping  $PING_ARG ${IP4_DST}
+	if [ $? -ne 0 ]; then
+		echo -e "${TEST}: ${RED}FAIL${NC}"
+		exit 1
+	fi
+	echo -e "${TEST}: ${GREEN}PASS${NC}"
+
+	TEST="ICMPv6 connectivity test"
+	ip netns exec ${NS_SRC} ping6 $PING_ARG ${IP6_DST}
+	if [ $? -ne 0 ]; then
+		echo -e "${TEST}: ${RED}FAIL${NC}"
+		exit 1
+	fi
+	echo -e "${TEST}: ${GREEN}PASS${NC}"
+
+	set -e
+}
+
+hex_mem_str()
+{
+	perl -e 'print join(" ", unpack("(H2)8", pack("L", @ARGV)))' $1
+}
+
+netns_setup_bpf()
+{
+	local obj=$1
+
+	ip netns exec ${NS_FWD} tc qdisc add dev veth_src_fwd clsact
+	ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd ingress bpf da obj $obj sec src_ingress
+	ip netns exec ${NS_FWD} tc filter add dev veth_src_fwd egress  bpf da obj $obj sec chk_egress
+
+	ip netns exec ${NS_FWD} tc qdisc add dev veth_dst_fwd clsact
+	ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd ingress bpf da obj $obj sec dst_ingress
+	ip netns exec ${NS_FWD} tc filter add dev veth_dst_fwd egress  bpf da obj $obj sec chk_egress
+
+	veth_src=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_src_fwd/ifindex)
+	veth_dst=$(ip netns exec ${NS_FWD} cat /sys/class/net/veth_dst_fwd/ifindex)
+
+	progs=$(ip netns exec ${NS_FWD} bpftool net --json | jq -r '.[] | .tc | map(.id) | .[]')
+	for prog in $progs; do
+		map=$(bpftool prog show id $prog --json | jq -r '.map_ids | .? | .[]')
+		if [ ! -z "$map" ]; then
+			bpftool map update id $map key hex $(hex_mem_str 0) value hex $(hex_mem_str $veth_src)
+			bpftool map update id $map key hex $(hex_mem_str 1) value hex $(hex_mem_str $veth_dst)
+		fi
+	done
+}
+
+trap netns_cleanup EXIT
+set -e
+
+netns_setup
+netns_setup_bpf test_tc_neigh.o
+netns_test_connectivity
+netns_cleanup
+netns_setup
+netns_setup_bpf test_tc_peer.o
+netns_test_connectivity