selftests/bpf: add simple BPF_PROG_TEST_RUN examples for flow dissector

Use existing pkt_v4 and pkt_v6 to make sure flow_keys are what we want.

Also, add new bpf_flow_load routine (and flow_dissector_load.h header)
that loads bpf_flow.o program and does all required setup.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/Makefile

@@ -148,6 +148,9 @@ $(OUTPUT)/test_xdp_noinline.o: CLANG_FLAGS += -fno-inline
 $(OUTPUT)/test_queue_map.o: test_queue_stack_map.h
 $(OUTPUT)/test_stack_map.o: test_queue_stack_map.h
 
+$(OUTPUT)/flow_dissector_load.o: flow_dissector_load.h
+$(OUTPUT)/test_progs.o: flow_dissector_load.h
+
 BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris)
 BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF)
 BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')

tools/testing/selftests/bpf/flow_dissector_load.c

@@ -12,6 +12,7 @@
 #include <bpf/libbpf.h>
 
 #include "bpf_rlimit.h"
+#include "flow_dissector_load.h"
 
 const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector";
 const char *cfg_map_name = "jmp_table";
@@ -21,46 +22,13 @@ char *cfg_path_name;
 
 static void load_and_attach_program(void)
 {
-	struct bpf_program *prog, *main_prog;
-	struct bpf_map *prog_array;
-	int i, fd, prog_fd, ret;
+	int prog_fd, ret;
 	struct bpf_object *obj;
-	int prog_array_fd;
 
-	ret = bpf_prog_load(cfg_path_name, BPF_PROG_TYPE_FLOW_DISSECTOR, &obj,
-			    &prog_fd);
+	ret = bpf_flow_load(&obj, cfg_path_name, cfg_section_name,
+			    cfg_map_name, &prog_fd);
 	if (ret)
-		error(1, 0, "bpf_prog_load %s", cfg_path_name);
-
-	main_prog = bpf_object__find_program_by_title(obj, cfg_section_name);
-	if (!main_prog)
-		error(1, 0, "bpf_object__find_program_by_title %s",
-		      cfg_section_name);
-
-	prog_fd = bpf_program__fd(main_prog);
-	if (prog_fd < 0)
-		error(1, 0, "bpf_program__fd");
-
-	prog_array = bpf_object__find_map_by_name(obj, cfg_map_name);
-	if (!prog_array)
-		error(1, 0, "bpf_object__find_map_by_name %s", cfg_map_name);
-
-	prog_array_fd = bpf_map__fd(prog_array);
-	if (prog_array_fd < 0)
-		error(1, 0, "bpf_map__fd %s", cfg_map_name);
-
-	i = 0;
-	bpf_object__for_each_program(prog, obj) {
-		fd = bpf_program__fd(prog);
-		if (fd < 0)
-			error(1, 0, "bpf_program__fd");
-
-		if (fd != prog_fd) {
-			printf("%d: %s\n", i, bpf_program__title(prog, false));
-			bpf_map_update_elem(prog_array_fd, &i, &fd, BPF_ANY);
-			++i;
-		}
-	}
+		error(1, 0, "bpf_flow_load %s", cfg_path_name);
 
 	ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0);
 	if (ret)
@@ -69,7 +37,6 @@ static void load_and_attach_program(void)
 	ret = bpf_object__pin(obj, cfg_pin_path);
 	if (ret)
 		error(1, 0, "bpf_object__pin %s", cfg_pin_path);
-
 }
 
 static void detach_program(void)

tools/testing/selftests/bpf/flow_dissector_load.h

+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+#ifndef FLOW_DISSECTOR_LOAD
+#define FLOW_DISSECTOR_LOAD
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+static inline int bpf_flow_load(struct bpf_object **obj,
+				const char *path,
+				const char *section_name,
+				const char *map_name,
+				int *prog_fd)
+{
+	struct bpf_program *prog, *main_prog;
+	struct bpf_map *prog_array;
+	int prog_array_fd;
+	int ret, fd, i;
+
+	ret = bpf_prog_load(path, BPF_PROG_TYPE_FLOW_DISSECTOR, obj,
+			    prog_fd);
+	if (ret)
+		return ret;
+
+	main_prog = bpf_object__find_program_by_title(*obj, section_name);
+	if (!main_prog)
+		return ret;
+
+	*prog_fd = bpf_program__fd(main_prog);
+	if (*prog_fd < 0)
+		return ret;
+
+	prog_array = bpf_object__find_map_by_name(*obj, map_name);
+	if (!prog_array)
+		return ret;
+
+	prog_array_fd = bpf_map__fd(prog_array);
+	if (prog_array_fd < 0)
+		return ret;
+
+	i = 0;
+	bpf_object__for_each_program(prog, *obj) {
+		fd = bpf_program__fd(prog);
+		if (fd < 0)
+			return fd;
+
+		if (fd != *prog_fd) {
+			bpf_map_update_elem(prog_array_fd, &i, &fd, BPF_ANY);
+			++i;
+		}
+	}
+
+	return 0;
+}
+
+#endif /* FLOW_DISSECTOR_LOAD */

tools/testing/selftests/bpf/test_progs.c

@@ -39,6 +39,7 @@ typedef __u16 __sum16;
 #include "bpf_endian.h"
 #include "bpf_rlimit.h"
 #include "trace_helpers.h"
+#include "flow_dissector_load.h"
 
 static int error_cnt, pass_cnt;
 static bool jit_enabled;
@@ -53,9 +54,10 @@ static struct {
 } __packed pkt_v4 = {
 	.eth.h_proto = __bpf_constant_htons(ETH_P_IP),
 	.iph.ihl = 5,
-	.iph.protocol = 6,
+	.iph.protocol = IPPROTO_TCP,
 	.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
 	.tcp.urg_ptr = 123,
+	.tcp.doff = 5,
 };
 
 /* ipv6 test vector */
@@ -65,9 +67,10 @@ static struct {
 	struct tcphdr tcp;
 } __packed pkt_v6 = {
 	.eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
-	.iph.nexthdr = 6,
+	.iph.nexthdr = IPPROTO_TCP,
 	.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
 	.tcp.urg_ptr = 123,
+	.tcp.doff = 5,
 };
 
 #define _CHECK(condition, tag, duration, format...) ({			\
@@ -1882,6 +1885,76 @@ static void test_queue_stack_map(int type)
 	bpf_object__close(obj);
 }
 
+#define CHECK_FLOW_KEYS(desc, got, expected)				\
+	CHECK(memcmp(&got, &expected, sizeof(got)) != 0,		\
+	      desc,							\
+	      "nhoff=%u/%u "						\
+	      "thoff=%u/%u "						\
+	      "addr_proto=0x%x/0x%x "					\
+	      "is_frag=%u/%u "						\
+	      "is_first_frag=%u/%u "					\
+	      "is_encap=%u/%u "						\
+	      "n_proto=0x%x/0x%x "					\
+	      "sport=%u/%u "						\
+	      "dport=%u/%u\n",						\
+	      got.nhoff, expected.nhoff,				\
+	      got.thoff, expected.thoff,				\
+	      got.addr_proto, expected.addr_proto,			\
+	      got.is_frag, expected.is_frag,				\
+	      got.is_first_frag, expected.is_first_frag,		\
+	      got.is_encap, expected.is_encap,				\
+	      got.n_proto, expected.n_proto,				\
+	      got.sport, expected.sport,				\
+	      got.dport, expected.dport)
+
+static struct bpf_flow_keys pkt_v4_flow_keys = {
+	.nhoff = 0,
+	.thoff = sizeof(struct iphdr),
+	.addr_proto = ETH_P_IP,
+	.ip_proto = IPPROTO_TCP,
+	.n_proto = bpf_htons(ETH_P_IP),
+};
+
+static struct bpf_flow_keys pkt_v6_flow_keys = {
+	.nhoff = 0,
+	.thoff = sizeof(struct ipv6hdr),
+	.addr_proto = ETH_P_IPV6,
+	.ip_proto = IPPROTO_TCP,
+	.n_proto = bpf_htons(ETH_P_IPV6),
+};
+
+static void test_flow_dissector(void)
+{
+	struct bpf_flow_keys flow_keys;
+	struct bpf_object *obj;
+	__u32 duration, retval;
+	int err, prog_fd;
+	__u32 size;
+
+	err = bpf_flow_load(&obj, "./bpf_flow.o", "flow_dissector",
+			    "jmp_table", &prog_fd);
+	if (err) {
+		error_cnt++;
+		return;
+	}
+
+	err = bpf_prog_test_run(prog_fd, 10, &pkt_v4, sizeof(pkt_v4),
+				&flow_keys, &size, &retval, &duration);
+	CHECK(size != sizeof(flow_keys) || err || retval != 1, "ipv4",
+	      "err %d errno %d retval %d duration %d size %u/%lu\n",
+	      err, errno, retval, duration, size, sizeof(flow_keys));
+	CHECK_FLOW_KEYS("ipv4_flow_keys", flow_keys, pkt_v4_flow_keys);
+
+	err = bpf_prog_test_run(prog_fd, 10, &pkt_v6, sizeof(pkt_v6),
+				&flow_keys, &size, &retval, &duration);
+	CHECK(size != sizeof(flow_keys) || err || retval != 1, "ipv6",
+	      "err %d errno %d retval %d duration %d size %u/%lu\n",
+	      err, errno, retval, duration, size, sizeof(flow_keys));
+	CHECK_FLOW_KEYS("ipv6_flow_keys", flow_keys, pkt_v6_flow_keys);
+
+	bpf_object__close(obj);
+}
+
 int main(void)
 {
 	srand(time(NULL));
@@ -1909,6 +1982,7 @@ int main(void)
 	test_reference_tracking();
 	test_queue_stack_map(QUEUE);
 	test_queue_stack_map(STACK);
+	test_flow_dissector();
 
 	printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
 	return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;