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>

1 files changed, 269 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/xdp_features.c b/tools/testing/selftests/bpf/progs/xdp_features.c
new file mode 100644
index 000000000000..87c247d56f72
--- /dev/null
+++ b/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";