selftests/bpf: Add tcp/udp iterator programs to selftests

Added tcp{4,6} and udp{4,6} bpf programs into test_progs
selftest so that they at least can load successfully.
  $ ./test_progs -n 3
  ...
  #3/7 tcp4:OK
  #3/8 tcp6:OK
  #3/9 udp4:OK
  #3/10 udp6:OK
  ...
  #3 bpf_iter:OK
  Summary: 1/16 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230823.3989372-1-yhs@fb.com

tools/testing/selftests/bpf/prog_tests/bpf_iter.c

@@ -6,6 +6,10 @@
 #include "bpf_iter_bpf_map.skel.h"
 #include "bpf_iter_task.skel.h"
 #include "bpf_iter_task_file.skel.h"
+#include "bpf_iter_tcp4.skel.h"
+#include "bpf_iter_tcp6.skel.h"
+#include "bpf_iter_udp4.skel.h"
+#include "bpf_iter_udp6.skel.h"
 #include "bpf_iter_test_kern1.skel.h"
 #include "bpf_iter_test_kern2.skel.h"
 #include "bpf_iter_test_kern3.skel.h"
@@ -120,6 +124,62 @@ static void test_task_file(void)
 	bpf_iter_task_file__destroy(skel);
 }
 
+static void test_tcp4(void)
+{
+	struct bpf_iter_tcp4 *skel;
+
+	skel = bpf_iter_tcp4__open_and_load();
+	if (CHECK(!skel, "bpf_iter_tcp4__open_and_load",
+		  "skeleton open_and_load failed\n"))
+		return;
+
+	do_dummy_read(skel->progs.dump_tcp4);
+
+	bpf_iter_tcp4__destroy(skel);
+}
+
+static void test_tcp6(void)
+{
+	struct bpf_iter_tcp6 *skel;
+
+	skel = bpf_iter_tcp6__open_and_load();
+	if (CHECK(!skel, "bpf_iter_tcp6__open_and_load",
+		  "skeleton open_and_load failed\n"))
+		return;
+
+	do_dummy_read(skel->progs.dump_tcp6);
+
+	bpf_iter_tcp6__destroy(skel);
+}
+
+static void test_udp4(void)
+{
+	struct bpf_iter_udp4 *skel;
+
+	skel = bpf_iter_udp4__open_and_load();
+	if (CHECK(!skel, "bpf_iter_udp4__open_and_load",
+		  "skeleton open_and_load failed\n"))
+		return;
+
+	do_dummy_read(skel->progs.dump_udp4);
+
+	bpf_iter_udp4__destroy(skel);
+}
+
+static void test_udp6(void)
+{
+	struct bpf_iter_udp6 *skel;
+
+	skel = bpf_iter_udp6__open_and_load();
+	if (CHECK(!skel, "bpf_iter_udp6__open_and_load",
+		  "skeleton open_and_load failed\n"))
+		return;
+
+	do_dummy_read(skel->progs.dump_udp6);
+
+	bpf_iter_udp6__destroy(skel);
+}
+
 /* The expected string is less than 16 bytes */
 static int do_read_with_fd(int iter_fd, const char *expected,
 			   bool read_one_char)
@@ -394,6 +454,14 @@ void test_bpf_iter(void)
 		test_task();
 	if (test__start_subtest("task_file"))
 		test_task_file();
+	if (test__start_subtest("tcp4"))
+		test_tcp4();
+	if (test__start_subtest("tcp6"))
+		test_tcp6();
+	if (test__start_subtest("udp4"))
+		test_udp4();
+	if (test__start_subtest("udp6"))
+		test_udp6();
 	if (test__start_subtest("anon"))
 		test_anon_iter(false);
 	if (test__start_subtest("anon-read-one-char"))