selftests, bpf: Add test for veth native XDP

Add a test case for veth native XDP. It checks if XDP_PASS, XDP_TX and
XDP_REDIRECT work properly.

$ cd tools/testing/selftests/bpf
$ make \
TEST_CUSTOM_PROGS= \
TEST_GEN_PROGS= \
TEST_GEN_PROGS_EXTENDED= \
TEST_PROGS_EXTENDED= \
TEST_PROGS="test_xdp_veth.sh" \
run_tests
TAP version 13
1..1
# selftests: bpf: test_xdp_veth.sh
# PING 10.1.1.33 (10.1.1.33) 56(84) bytes of data.
# 64 bytes from 10.1.1.33: icmp_seq=1 ttl=64 time=0.073 ms
#
# --- 10.1.1.33 ping statistics ---
# 1 packets transmitted, 1 received, 0% packet loss, time 0ms
# rtt min/avg/max/mdev = 0.073/0.073/0.073/0.000 ms
# selftests: xdp_veth [PASS]
ok 1 selftests: bpf: test_xdp_veth.sh

Signed-off-by: Toshiaki Makita <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/Makefile

···
 	test_libbpf.sh \
 	test_xdp_redirect.sh \
 	test_xdp_meta.sh \
+	test_xdp_veth.sh \
 	test_offload.py \
 	test_sock_addr.sh \
 	test_tunnel.sh \

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

···
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") tx_port = {
+	.type = BPF_MAP_TYPE_DEVMAP,
+	.key_size = sizeof(int),
+	.value_size = sizeof(int),
+	.max_entries = 8,
+};
+
+SEC("redirect_map_0")
+int xdp_redirect_map_0(struct xdp_md *xdp)
+{
+	return bpf_redirect_map(&tx_port, 0, 0);
+}
+
+SEC("redirect_map_1")
+int xdp_redirect_map_1(struct xdp_md *xdp)
+{
+	return bpf_redirect_map(&tx_port, 1, 0);
+}
+
+SEC("redirect_map_2")
+int xdp_redirect_map_2(struct xdp_md *xdp)
+{
+	return bpf_redirect_map(&tx_port, 2, 0);
+}
+
+char _license[] SEC("license") = "GPL";

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

···
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+SEC("tx")
+int xdp_tx(struct xdp_md *xdp)
+{
+	return XDP_TX;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_xdp_veth.sh

···
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Create 3 namespaces with 3 veth peers, and
+# forward packets in-between using native XDP
+#
+#                      XDP_TX
+# NS1(veth11)        NS2(veth22)        NS3(veth33)
+#      |                  |                  |
+#      |                  |                  |
+#   (veth1,            (veth2,            (veth3,
+#   id:111)            id:122)            id:133)
+#     ^ |                ^ |                ^ |
+#     | |  XDP_REDIRECT  | |  XDP_REDIRECT  | |
+#     | ------------------ ------------------ |
+#     -----------------------------------------
+#                    XDP_REDIRECT
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+TESTNAME=xdp_veth
+BPF_FS=$(awk '$3 == "bpf" {print $2; exit}' /proc/mounts)
+BPF_DIR=$BPF_FS/test_$TESTNAME
+
+_cleanup()
+{
+	set +e
+	ip link del veth1 2> /dev/null
+	ip link del veth2 2> /dev/null
+	ip link del veth3 2> /dev/null
+	ip netns del ns1 2> /dev/null
+	ip netns del ns2 2> /dev/null
+	ip netns del ns3 2> /dev/null
+	rm -rf $BPF_DIR 2> /dev/null
+}
+
+cleanup_skip()
+{
+	echo "selftests: $TESTNAME [SKIP]"
+	_cleanup
+
+	exit $ksft_skip
+}
+
+cleanup()
+{
+	if [ "$?" = 0 ]; then
+		echo "selftests: $TESTNAME [PASS]"
+	else
+		echo "selftests: $TESTNAME [FAILED]"
+	fi
+	_cleanup
+}
+
+if [ $(id -u) -ne 0 ]; then
+	echo "selftests: $TESTNAME [SKIP] Need root privileges"
+	exit $ksft_skip
+fi
+
+if ! ip link set dev lo xdp off > /dev/null 2>&1; then
+	echo "selftests: $TESTNAME [SKIP] Could not run test without the ip xdp support"
+	exit $ksft_skip
+fi
+
+if [ -z "$BPF_FS" ]; then
+	echo "selftests: $TESTNAME [SKIP] Could not run test without bpffs mounted"
+	exit $ksft_skip
+fi
+
+if ! bpftool version > /dev/null 2>&1; then
+	echo "selftests: $TESTNAME [SKIP] Could not run test without bpftool"
+	exit $ksft_skip
+fi
+
+set -e
+
+trap cleanup_skip EXIT
+
+ip netns add ns1
+ip netns add ns2
+ip netns add ns3
+
+ip link add veth1 index 111 type veth peer name veth11 netns ns1
+ip link add veth2 index 122 type veth peer name veth22 netns ns2
+ip link add veth3 index 133 type veth peer name veth33 netns ns3
+
+ip link set veth1 up
+ip link set veth2 up
+ip link set veth3 up
+
+ip -n ns1 addr add 10.1.1.11/24 dev veth11
+ip -n ns3 addr add 10.1.1.33/24 dev veth33
+
+ip -n ns1 link set dev veth11 up
+ip -n ns2 link set dev veth22 up
+ip -n ns3 link set dev veth33 up
+
+mkdir $BPF_DIR
+bpftool prog loadall \
+	xdp_redirect_map.o $BPF_DIR/progs type xdp \
+	pinmaps $BPF_DIR/maps
+bpftool map update pinned $BPF_DIR/maps/tx_port key 0 0 0 0 value 122 0 0 0
+bpftool map update pinned $BPF_DIR/maps/tx_port key 1 0 0 0 value 133 0 0 0
+bpftool map update pinned $BPF_DIR/maps/tx_port key 2 0 0 0 value 111 0 0 0
+ip link set dev veth1 xdp pinned $BPF_DIR/progs/redirect_map_0
+ip link set dev veth2 xdp pinned $BPF_DIR/progs/redirect_map_1
+ip link set dev veth3 xdp pinned $BPF_DIR/progs/redirect_map_2
+
+ip -n ns1 link set dev veth11 xdp obj xdp_dummy.o sec xdp_dummy
+ip -n ns2 link set dev veth22 xdp obj xdp_tx.o sec tx
+ip -n ns3 link set dev veth33 xdp obj xdp_dummy.o sec xdp_dummy
+
+trap cleanup EXIT
+
+ip netns exec ns1 ping -c 1 -W 1 10.1.1.33
+
+exit 0