Merge branch 'selftests/bpf: convert three other cgroup tests to test_progs'

Alexis Lothoré (eBPF Foundation) says:

====================
Hello,
this series brings a new set of test converted to the test_progs framework.
Since the tests are quite small, I chose to group three tests conversion in
the same series, but feel free to let me know if I should keep one series
per test. The series focuses on cgroup testing and converts the following
tests:
- get_cgroup_id_user
- cgroup_storage
- test_skb_cgroup_id_user

Changes in v4:
- Fix test after netns addition by making sure loopack interface is up
- Link to v3: https://lore.kernel.org/r/20240812-convert_cgroup_tests-v3-0-47ac6ce4e88b@bootlin.com

Changes in v3:
- Fixed multiple leaks on cgroup file descriptors and sockets
- Used dedicated network namespaces for tests involving network
- Link to v2: https://lore.kernel.org/r/20240806-convert_cgroup_tests-v2-0-180c57e5b710@bootlin.com

Changes in v2:
- Use global variables instead of maps when possible
- Collect review tags from Alan
- Link to v1: https://lore.kernel.org/r/20240731-convert_cgroup_tests-v1-0-14cbc51b6947@bootlin.com
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

tools/testing/selftests/bpf/.gitignore

@@ -19,9 +19,6 @@ test_sock
 urandom_read
 test_sockmap
 test_lirc_mode2_user
-get_cgroup_id_user
-test_skb_cgroup_id_user
-test_cgroup_storage
 test_flow_dissector
 flow_dissector_load
 test_tcpnotify_user

tools/testing/selftests/bpf/Makefile

@@ -67,8 +67,7 @@ endif
 
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
-	test_sock test_sockmap get_cgroup_id_user \
-	test_cgroup_storage \
+	test_sock test_sockmap \
 	test_tcpnotify_user test_sysctl \
 	test_progs-no_alu32
 TEST_INST_SUBDIRS := no_alu32
@@ -138,7 +137,7 @@ TEST_PROGS_EXTENDED := with_addr.sh \
 	test_xdp_vlan.sh test_bpftool.py
 
 # Compile but not part of 'make run_tests'
-TEST_GEN_PROGS_EXTENDED = test_skb_cgroup_id_user \
+TEST_GEN_PROGS_EXTENDED = \
 	flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
 	test_lirc_mode2_user xdping test_cpp runqslower bench bpf_testmod.ko \
 	xskxceiver xdp_redirect_multi xdp_synproxy veristat xdp_hw_metadata \
@@ -291,12 +290,9 @@ JSON_WRITER		:= $(OUTPUT)/json_writer.o
 CAP_HELPERS	:= $(OUTPUT)/cap_helpers.o
 NETWORK_HELPERS := $(OUTPUT)/network_helpers.o
 
-$(OUTPUT)/test_skb_cgroup_id_user: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sock: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sockmap: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_tcpnotify_user: $(CGROUP_HELPERS) $(TESTING_HELPERS) $(TRACE_HELPERS)
-$(OUTPUT)/get_cgroup_id_user: $(CGROUP_HELPERS) $(TESTING_HELPERS)
-$(OUTPUT)/test_cgroup_storage: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sock_fields: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sysctl: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_tag: $(TESTING_HELPERS)

tools/testing/selftests/bpf/get_cgroup_id_user.c

-// SPDX-License-Identifier: GPL-2.0
-// Copyright (c) 2018 Facebook
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <syscall.h>
-#include <unistd.h>
-#include <linux/perf_event.h>
-#include <sys/ioctl.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-
-#include <linux/bpf.h>
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "cgroup_helpers.h"
-#include "testing_helpers.h"
-
-#define CHECK(condition, tag, format...) ({		\
-	int __ret = !!(condition);			\
-	if (__ret) {					\
-		printf("%s:FAIL:%s ", __func__, tag);	\
-		printf(format);				\
-	} else {					\
-		printf("%s:PASS:%s\n", __func__, tag);	\
-	}						\
-	__ret;						\
-})
-
-static int bpf_find_map(const char *test, struct bpf_object *obj,
-			const char *name)
-{
-	struct bpf_map *map;
-
-	map = bpf_object__find_map_by_name(obj, name);
-	if (!map)
-		return -1;
-	return bpf_map__fd(map);
-}
-
-#define TEST_CGROUP "/test-bpf-get-cgroup-id/"
-
-int main(int argc, char **argv)
-{
-	const char *probe_name = "syscalls/sys_enter_nanosleep";
-	const char *file = "get_cgroup_id_kern.bpf.o";
-	int err, bytes, efd, prog_fd, pmu_fd;
-	int cgroup_fd, cgidmap_fd, pidmap_fd;
-	struct perf_event_attr attr = {};
-	struct bpf_object *obj;
-	__u64 kcgid = 0, ucgid;
-	__u32 key = 0, pid;
-	int exit_code = 1;
-	char buf[256];
-	const struct timespec req = {
-		.tv_sec = 1,
-		.tv_nsec = 0,
-	};
-
-	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
-	if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno))
-		return 1;
-
-	/* Use libbpf 1.0 API mode */
-	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
-	err = bpf_prog_test_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
-	if (CHECK(err, "bpf_prog_test_load", "err %d errno %d\n", err, errno))
-		goto cleanup_cgroup_env;
-
-	cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids");
-	if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
-		  cgidmap_fd, errno))
-		goto close_prog;
-
-	pidmap_fd = bpf_find_map(__func__, obj, "pidmap");
-	if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n",
-		  pidmap_fd, errno))
-		goto close_prog;
-
-	pid = getpid();
-	bpf_map_update_elem(pidmap_fd, &key, &pid, 0);
-
-	if (access("/sys/kernel/tracing/trace", F_OK) == 0) {
-		snprintf(buf, sizeof(buf),
-			 "/sys/kernel/tracing/events/%s/id", probe_name);
-	} else {
-		snprintf(buf, sizeof(buf),
-			 "/sys/kernel/debug/tracing/events/%s/id", probe_name);
-	}
-	efd = open(buf, O_RDONLY, 0);
-	if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
-		goto close_prog;
-	bytes = read(efd, buf, sizeof(buf));
-	close(efd);
-	if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read",
-		  "bytes %d errno %d\n", bytes, errno))
-		goto close_prog;
-
-	attr.config = strtol(buf, NULL, 0);
-	attr.type = PERF_TYPE_TRACEPOINT;
-	attr.sample_type = PERF_SAMPLE_RAW;
-	attr.sample_period = 1;
-	attr.wakeup_events = 1;
-
-	/* attach to this pid so the all bpf invocations will be in the
-	 * cgroup associated with this pid.
-	 */
-	pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
-	if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd,
-		  errno))
-		goto close_prog;
-
-	err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
-	if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err,
-		  errno))
-		goto close_pmu;
-
-	err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
-	if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err,
-		  errno))
-		goto close_pmu;
-
-	/* trigger some syscalls */
-	syscall(__NR_nanosleep, &req, NULL);
-
-	err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid);
-	if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno))
-		goto close_pmu;
-
-	ucgid = get_cgroup_id(TEST_CGROUP);
-	if (CHECK(kcgid != ucgid, "compare_cgroup_id",
-		  "kern cgid %llx user cgid %llx", kcgid, ucgid))
-		goto close_pmu;
-
-	exit_code = 0;
-	printf("%s:PASS\n", argv[0]);
-
-close_pmu:
-	close(pmu_fd);
-close_prog:
-	bpf_object__close(obj);
-cleanup_cgroup_env:
-	cleanup_cgroup_environment();
-	return exit_code;
-}

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

+// SPDX-License-Identifier: GPL-2.0
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "cgroup_helpers.h"
+#include "cgroup_ancestor.skel.h"
+
+#define CGROUP_PATH "/skb_cgroup_test"
+#define TEST_NS "cgroup_ancestor_ns"
+#define NUM_CGROUP_LEVELS 4
+#define WAIT_AUTO_IP_MAX_ATTEMPT 10
+#define DST_ADDR "::1"
+#define DST_PORT 1234
+#define MAX_ASSERT_NAME 32
+
+struct test_data {
+	struct cgroup_ancestor *skel;
+	struct bpf_tc_hook qdisc;
+	struct bpf_tc_opts tc_attach;
+	struct nstoken *ns;
+};
+
+static int send_datagram(void)
+{
+	unsigned char buf[] = "some random test data";
+	struct sockaddr_in6 addr = { .sin6_family = AF_INET6,
+				     .sin6_port = htons(DST_PORT), };
+	int sock, n;
+
+	if (!ASSERT_EQ(inet_pton(AF_INET6, DST_ADDR, &addr.sin6_addr), 1,
+		       "inet_pton"))
+		return -1;
+
+	sock = socket(AF_INET6, SOCK_DGRAM, 0);
+	if (!ASSERT_OK_FD(sock, "create socket"))
+		return sock;
+
+	if (!ASSERT_OK(connect(sock, &addr, sizeof(addr)), "connect")) {
+		close(sock);
+		return -1;
+	}
+
+	n = sendto(sock, buf, sizeof(buf), 0, (const struct sockaddr *)&addr,
+		   sizeof(addr));
+	close(sock);
+	return ASSERT_EQ(n, sizeof(buf), "send data") ? 0 : -1;
+}
+
+static int setup_network(struct test_data *t)
+{
+	SYS(fail, "ip netns add %s", TEST_NS);
+	t->ns = open_netns(TEST_NS);
+	if (!ASSERT_OK_PTR(t->ns, "open netns"))
+		goto cleanup_ns;
+
+	SYS(close_ns, "ip link set lo up");
+
+	memset(&t->qdisc, 0, sizeof(t->qdisc));
+	t->qdisc.sz = sizeof(t->qdisc);
+	t->qdisc.attach_point = BPF_TC_EGRESS;
+	t->qdisc.ifindex = if_nametoindex("lo");
+	if (!ASSERT_NEQ(t->qdisc.ifindex, 0, "if_nametoindex"))
+		goto close_ns;
+	if (!ASSERT_OK(bpf_tc_hook_create(&t->qdisc), "qdisc add"))
+		goto close_ns;
+
+	memset(&t->tc_attach, 0, sizeof(t->tc_attach));
+	t->tc_attach.sz = sizeof(t->tc_attach);
+	t->tc_attach.prog_fd = bpf_program__fd(t->skel->progs.log_cgroup_id);
+	if (!ASSERT_OK(bpf_tc_attach(&t->qdisc, &t->tc_attach), "filter add"))
+		goto cleanup_qdisc;
+
+	return 0;
+
+cleanup_qdisc:
+	bpf_tc_hook_destroy(&t->qdisc);
+close_ns:
+	close_netns(t->ns);
+cleanup_ns:
+	SYS_NOFAIL("ip netns del %s", TEST_NS);
+fail:
+	return 1;
+}
+
+static void cleanup_network(struct test_data *t)
+{
+	bpf_tc_detach(&t->qdisc, &t->tc_attach);
+	bpf_tc_hook_destroy(&t->qdisc);
+	close_netns(t->ns);
+	SYS_NOFAIL("ip netns del %s", TEST_NS);
+}
+
+static void check_ancestors_ids(struct test_data *t)
+{
+	__u64 expected_ids[NUM_CGROUP_LEVELS];
+	char assert_name[MAX_ASSERT_NAME];
+	__u32 level;
+
+	expected_ids[0] = get_cgroup_id("/.."); /* root cgroup */
+	expected_ids[1] = get_cgroup_id("");
+	expected_ids[2] = get_cgroup_id(CGROUP_PATH);
+	expected_ids[3] = 0; /* non-existent cgroup */
+
+	for (level = 0; level < NUM_CGROUP_LEVELS; level++) {
+		snprintf(assert_name, MAX_ASSERT_NAME,
+			 "ancestor id at level %d", level);
+		ASSERT_EQ(t->skel->bss->cgroup_ids[level], expected_ids[level],
+			  assert_name);
+	}
+}
+
+void test_cgroup_ancestor(void)
+{
+	struct test_data t;
+	int cgroup_fd;
+
+	t.skel = cgroup_ancestor__open_and_load();
+	if (!ASSERT_OK_PTR(t.skel, "open and load"))
+		return;
+
+	t.skel->bss->dport = htons(DST_PORT);
+	cgroup_fd = cgroup_setup_and_join(CGROUP_PATH);
+	if (cgroup_fd < 0)
+		goto cleanup_progs;
+
+	if (setup_network(&t))
+		goto cleanup_cgroups;
+
+	if (send_datagram())
+		goto cleanup_network;
+
+	check_ancestors_ids(&t);
+
+cleanup_network:
+	cleanup_network(&t);
+cleanup_cgroups:
+	close(cgroup_fd);
+	cleanup_cgroup_environment();
+cleanup_progs:
+	cgroup_ancestor__destroy(t.skel);
+}

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

+// SPDX-License-Identifier: GPL-2.0
+
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include "test_progs.h"
+#include "cgroup_helpers.h"
+#include "get_cgroup_id_kern.skel.h"
+
+#define TEST_CGROUP "/test-bpf-get-cgroup-id/"
+
+void test_cgroup_get_current_cgroup_id(void)
+{
+	struct get_cgroup_id_kern *skel;
+	const struct timespec req = {
+		.tv_sec = 0,
+		.tv_nsec = 1,
+	};
+	int cgroup_fd;
+	__u64 ucgid;
+
+	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+	if (!ASSERT_OK_FD(cgroup_fd, "cgroup switch"))
+		return;
+
+	skel = get_cgroup_id_kern__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "load program"))
+		goto cleanup_cgroup;
+
+	if (!ASSERT_OK(get_cgroup_id_kern__attach(skel), "attach bpf program"))
+		goto cleanup_progs;
+
+	skel->bss->expected_pid = getpid();
+	/* trigger the syscall on which is attached the tested prog */
+	if (!ASSERT_OK(syscall(__NR_nanosleep, &req, NULL), "nanosleep"))
+		goto cleanup_progs;
+
+	ucgid = get_cgroup_id(TEST_CGROUP);
+
+	ASSERT_EQ(skel->bss->cg_id, ucgid, "compare cgroup ids");
+
+cleanup_progs:
+	get_cgroup_id_kern__destroy(skel);
+cleanup_cgroup:
+	close(cgroup_fd);
+	cleanup_cgroup_environment();
+}

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

+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include "cgroup_helpers.h"
+#include "network_helpers.h"
+#include "cgroup_storage.skel.h"
+
+#define TEST_CGROUP "/test-bpf-cgroup-storage-buf/"
+#define TEST_NS "cgroup_storage_ns"
+#define PING_CMD "ping localhost -c 1 -W 1 -q"
+
+static int setup_network(struct nstoken **token)
+{
+	SYS(fail, "ip netns add %s", TEST_NS);
+	*token = open_netns(TEST_NS);
+	if (!ASSERT_OK_PTR(*token, "open netns"))
+		goto cleanup_ns;
+	SYS(cleanup_ns, "ip link set lo up");
+
+	return 0;
+
+cleanup_ns:
+	SYS_NOFAIL("ip netns del %s", TEST_NS);
+fail:
+	return -1;
+}
+
+static void cleanup_network(struct nstoken *ns)
+{
+	close_netns(ns);
+	SYS_NOFAIL("ip netns del %s", TEST_NS);
+}
+
+void test_cgroup_storage(void)
+{
+	struct bpf_cgroup_storage_key key;
+	struct cgroup_storage *skel;
+	struct nstoken *ns = NULL;
+	unsigned long long value;
+	int cgroup_fd;
+	int err;
+
+	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+	if (!ASSERT_OK_FD(cgroup_fd, "create cgroup"))
+		return;
+
+	if (!ASSERT_OK(setup_network(&ns), "setup network"))
+		goto cleanup_cgroup;
+
+	skel = cgroup_storage__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "load program"))
+		goto cleanup_network;
+
+	skel->links.bpf_prog =
+		bpf_program__attach_cgroup(skel->progs.bpf_prog, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.bpf_prog, "attach program"))
+		goto cleanup_progs;
+
+	/* Check that one out of every two packets is dropped */
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_OK(err, "first ping");
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_NEQ(err, 0, "second ping");
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_OK(err, "third ping");
+
+	err = bpf_map__get_next_key(skel->maps.cgroup_storage, NULL, &key,
+				    sizeof(key));
+	if (!ASSERT_OK(err, "get first key"))
+		goto cleanup_progs;
+	err = bpf_map__lookup_elem(skel->maps.cgroup_storage, &key, sizeof(key),
+				   &value, sizeof(value), 0);
+	if (!ASSERT_OK(err, "first packet count read"))
+		goto cleanup_progs;
+
+	/* Add one to the packet counter, check again packet filtering */
+	value++;
+	err = bpf_map__update_elem(skel->maps.cgroup_storage, &key, sizeof(key),
+				   &value, sizeof(value), 0);
+	if (!ASSERT_OK(err, "increment packet counter"))
+		goto cleanup_progs;
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_OK(err, "fourth ping");
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_NEQ(err, 0, "fifth ping");
+	err = SYS_NOFAIL(PING_CMD);
+	ASSERT_OK(err, "sixth ping");
+
+cleanup_progs:
+	cgroup_storage__destroy(skel);
+cleanup_network:
+	cleanup_network(ns);
+cleanup_cgroup:
+	close(cgroup_fd);
+	cleanup_cgroup_environment();
+}

tools/testing/selftests/bpf/progs/test_skb_cgroup_id_kern.c → tools/testing/selftests/bpf/progs/cgroup_ancestor.c

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2018 Facebook
 
-#include <linux/bpf.h>
-#include <linux/pkt_cls.h>
-
-#include <string.h>
-
+#include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
+#include <bpf/bpf_core_read.h>
+#include "bpf_tracing_net.h"
 #define NUM_CGROUP_LEVELS	4
 
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__type(key, __u32);
-	__type(value, __u64);
-	__uint(max_entries, NUM_CGROUP_LEVELS);
-} cgroup_ids SEC(".maps");
+__u64 cgroup_ids[NUM_CGROUP_LEVELS];
+__u16 dport;
 
 static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level)
 {
-	__u64 id;
-
 	/* [1] &level passed to external function that may change it, it's
 	 *     incompatible with loop unroll.
 	 */
-	id = bpf_skb_ancestor_cgroup_id(skb, level);
-	bpf_map_update_elem(&cgroup_ids, &level, &id, 0);
+	cgroup_ids[level] = bpf_skb_ancestor_cgroup_id(skb, level);
 }
 
-SEC("cgroup_id_logger")
+SEC("tc")
 int log_cgroup_id(struct __sk_buff *skb)
 {
-	/* Loop unroll can't be used here due to [1]. Unrolling manually.
-	 * Number of calls should be in sync with NUM_CGROUP_LEVELS.
-	 */
-	log_nth_level(skb, 0);
-	log_nth_level(skb, 1);
-	log_nth_level(skb, 2);
-	log_nth_level(skb, 3);
+	struct sock *sk = (void *)skb->sk;
+
+	if (!sk)
+		return TC_ACT_OK;
+
+	sk = bpf_core_cast(sk, struct sock);
+	if (sk->sk_protocol == IPPROTO_UDP && sk->sk_dport == dport) {
+		log_nth_level(skb, 0);
+		log_nth_level(skb, 1);
+		log_nth_level(skb, 2);
+		log_nth_level(skb, 3);
+	}
 
 	return TC_ACT_OK;
 }

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

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGROUP_STORAGE);
+	__type(key, struct bpf_cgroup_storage_key);
+	__type(value, __u64);
+} cgroup_storage SEC(".maps");
+
+SEC("cgroup_skb/egress")
+int bpf_prog(struct __sk_buff *skb)
+{
+	__u64 *counter;
+
+	counter = bpf_get_local_storage(&cgroup_storage, 0);
+	__sync_fetch_and_add(counter, 1);
+
+	/* Drop one out of every two packets */
+	return (*counter & 1);
+}
+
+char _license[] SEC("license") = "GPL";

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

@@ -4,34 +4,16 @@
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__uint(max_entries, 1);
-	__type(key, __u32);
-	__type(value, __u64);
-} cg_ids SEC(".maps");
-
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__uint(max_entries, 1);
-	__type(key, __u32);
-	__type(value, __u32);
-} pidmap SEC(".maps");
+__u64 cg_id;
+__u64 expected_pid;
 
 SEC("tracepoint/syscalls/sys_enter_nanosleep")
 int trace(void *ctx)
 {
 	__u32 pid = bpf_get_current_pid_tgid();
-	__u32 key = 0, *expected_pid;
-	__u64 *val;
-
-	expected_pid = bpf_map_lookup_elem(&pidmap, &key);
-	if (!expected_pid || *expected_pid != pid)
-		return 0;
 
-	val = bpf_map_lookup_elem(&cg_ids, &key);
-	if (val)
-		*val = bpf_get_current_cgroup_id();
+	if (expected_pid == pid)
+		cg_id = bpf_get_current_cgroup_id();
 
 	return 0;
 }

tools/testing/selftests/bpf/test_cgroup_storage.c

-// SPDX-License-Identifier: GPL-2.0
-#include <assert.h>
-#include <bpf/bpf.h>
-#include <linux/filter.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/sysinfo.h>
-
-#include "bpf_util.h"
-#include "cgroup_helpers.h"
-#include "testing_helpers.h"
-
-char bpf_log_buf[BPF_LOG_BUF_SIZE];
-
-#define TEST_CGROUP "/test-bpf-cgroup-storage-buf/"
-
-int main(int argc, char **argv)
-{
-	struct bpf_insn prog[] = {
-		BPF_LD_MAP_FD(BPF_REG_1, 0), /* percpu map fd */
-		BPF_MOV64_IMM(BPF_REG_2, 0), /* flags, not used */
-		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
-			     BPF_FUNC_get_local_storage),
-		BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0),
-		BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 0x1),
-		BPF_STX_MEM(BPF_DW, BPF_REG_0, BPF_REG_3, 0),
-
-		BPF_LD_MAP_FD(BPF_REG_1, 0), /* map fd */
-		BPF_MOV64_IMM(BPF_REG_2, 0), /* flags, not used */
-		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
-			     BPF_FUNC_get_local_storage),
-		BPF_MOV64_IMM(BPF_REG_1, 1),
-		BPF_ATOMIC_OP(BPF_DW, BPF_ADD, BPF_REG_0, BPF_REG_1, 0),
-		BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0),
-		BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0x1),
-		BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
-		BPF_EXIT_INSN(),
-	};
-	size_t insns_cnt = ARRAY_SIZE(prog);
-	int error = EXIT_FAILURE;
-	int map_fd, percpu_map_fd, prog_fd, cgroup_fd;
-	struct bpf_cgroup_storage_key key;
-	unsigned long long value;
-	unsigned long long *percpu_value;
-	int cpu, nproc;
-
-	nproc = bpf_num_possible_cpus();
-	percpu_value = malloc(sizeof(*percpu_value) * nproc);
-	if (!percpu_value) {
-		printf("Not enough memory for per-cpu area (%d cpus)\n", nproc);
-		goto err;
-	}
-
-	/* Use libbpf 1.0 API mode */
-	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
-	map_fd = bpf_map_create(BPF_MAP_TYPE_CGROUP_STORAGE, NULL, sizeof(key),
-				sizeof(value), 0, NULL);
-	if (map_fd < 0) {
-		printf("Failed to create map: %s\n", strerror(errno));
-		goto out;
-	}
-
-	percpu_map_fd = bpf_map_create(BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, NULL,
-				       sizeof(key), sizeof(value), 0, NULL);
-	if (percpu_map_fd < 0) {
-		printf("Failed to create map: %s\n", strerror(errno));
-		goto out;
-	}
-
-	prog[0].imm = percpu_map_fd;
-	prog[7].imm = map_fd;
-	prog_fd = bpf_test_load_program(BPF_PROG_TYPE_CGROUP_SKB,
-				   prog, insns_cnt, "GPL", 0,
-				   bpf_log_buf, BPF_LOG_BUF_SIZE);
-	if (prog_fd < 0) {
-		printf("Failed to load bpf program: %s\n", bpf_log_buf);
-		goto out;
-	}
-
-	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
-
-	/* Attach the bpf program */
-	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_INET_EGRESS, 0)) {
-		printf("Failed to attach bpf program\n");
-		goto err;
-	}
-
-	if (bpf_map_get_next_key(map_fd, NULL, &key)) {
-		printf("Failed to get the first key in cgroup storage\n");
-		goto err;
-	}
-
-	if (bpf_map_lookup_elem(map_fd, &key, &value)) {
-		printf("Failed to lookup cgroup storage 0\n");
-		goto err;
-	}
-
-	for (cpu = 0; cpu < nproc; cpu++)
-		percpu_value[cpu] = 1000;
-
-	if (bpf_map_update_elem(percpu_map_fd, &key, percpu_value, 0)) {
-		printf("Failed to update the data in the cgroup storage\n");
-		goto err;
-	}
-
-	/* Every second packet should be dropped */
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null") == 0);
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null"));
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null") == 0);
-
-	/* Check the counter in the cgroup local storage */
-	if (bpf_map_lookup_elem(map_fd, &key, &value)) {
-		printf("Failed to lookup cgroup storage\n");
-		goto err;
-	}
-
-	if (value != 3) {
-		printf("Unexpected data in the cgroup storage: %llu\n", value);
-		goto err;
-	}
-
-	/* Bump the counter in the cgroup local storage */
-	value++;
-	if (bpf_map_update_elem(map_fd, &key, &value, 0)) {
-		printf("Failed to update the data in the cgroup storage\n");
-		goto err;
-	}
-
-	/* Every second packet should be dropped */
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null") == 0);
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null"));
-	assert(system("ping localhost -c 1 -W 1 -q > /dev/null") == 0);
-
-	/* Check the final value of the counter in the cgroup local storage */
-	if (bpf_map_lookup_elem(map_fd, &key, &value)) {
-		printf("Failed to lookup the cgroup storage\n");
-		goto err;
-	}
-
-	if (value != 7) {
-		printf("Unexpected data in the cgroup storage: %llu\n", value);
-		goto err;
-	}
-
-	/* Check the final value of the counter in the percpu local storage */
-
-	for (cpu = 0; cpu < nproc; cpu++)
-		percpu_value[cpu] = 0;
-
-	if (bpf_map_lookup_elem(percpu_map_fd, &key, percpu_value)) {
-		printf("Failed to lookup the per-cpu cgroup storage\n");
-		goto err;
-	}
-
-	value = 0;
-	for (cpu = 0; cpu < nproc; cpu++)
-		value += percpu_value[cpu];
-
-	if (value != nproc * 1000 + 6) {
-		printf("Unexpected data in the per-cpu cgroup storage\n");
-		goto err;
-	}
-
-	error = 0;
-	printf("test_cgroup_storage:PASS\n");
-
-err:
-	cleanup_cgroup_environment();
-	free(percpu_value);
-
-out:
-	return error;
-}

tools/testing/selftests/bpf/test_skb_cgroup_id.sh

-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-# Copyright (c) 2018 Facebook
-
-set -eu
-
-wait_for_ip()
-{
-	local _i
-	echo -n "Wait for testing link-local IP to become available "
-	for _i in $(seq ${MAX_PING_TRIES}); do
-		echo -n "."
-		if $PING6 -c 1 -W 1 ff02::1%${TEST_IF} >/dev/null 2>&1; then
-			echo " OK"
-			return
-		fi
-		sleep 1
-	done
-	echo 1>&2 "ERROR: Timeout waiting for test IP to become available."
-	exit 1
-}
-
-setup()
-{
-	# Create testing interfaces not to interfere with current environment.
-	ip link add dev ${TEST_IF} type veth peer name ${TEST_IF_PEER}
-	ip link set ${TEST_IF} up
-	ip link set ${TEST_IF_PEER} up
-
-	wait_for_ip
-
-	tc qdisc add dev ${TEST_IF} clsact
-	tc filter add dev ${TEST_IF} egress bpf obj ${BPF_PROG_OBJ} \
-		sec ${BPF_PROG_SECTION} da
-
-	BPF_PROG_ID=$(tc filter show dev ${TEST_IF} egress | \
-			awk '/ id / {sub(/.* id /, "", $0); print($1)}')
-}
-
-cleanup()
-{
-	ip link del ${TEST_IF} 2>/dev/null || :
-	ip link del ${TEST_IF_PEER} 2>/dev/null || :
-}
-
-main()
-{
-	trap cleanup EXIT 2 3 6 15
-	setup
-	${PROG} ${TEST_IF} ${BPF_PROG_ID}
-}
-
-DIR=$(dirname $0)
-TEST_IF="test_cgid_1"
-TEST_IF_PEER="test_cgid_2"
-MAX_PING_TRIES=5
-BPF_PROG_OBJ="${DIR}/test_skb_cgroup_id_kern.bpf.o"
-BPF_PROG_SECTION="cgroup_id_logger"
-BPF_PROG_ID=0
-PROG="${DIR}/test_skb_cgroup_id_user"
-type ping6 >/dev/null 2>&1 && PING6="ping6" || PING6="ping -6"
-
-main

tools/testing/selftests/bpf/test_skb_cgroup_id_user.c

-// SPDX-License-Identifier: GPL-2.0
-// Copyright (c) 2018 Facebook
-
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <arpa/inet.h>
-#include <net/if.h>
-#include <netinet/in.h>
-#include <sys/socket.h>
-#include <sys/types.h>
-
-
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "cgroup_helpers.h"
-
-#define CGROUP_PATH		"/skb_cgroup_test"
-#define NUM_CGROUP_LEVELS	4
-
-/* RFC 4291, Section 2.7.1 */
-#define LINKLOCAL_MULTICAST	"ff02::1"
-
-static int mk_dst_addr(const char *ip, const char *iface,
-		       struct sockaddr_in6 *dst)
-{
-	memset(dst, 0, sizeof(*dst));
-
-	dst->sin6_family = AF_INET6;
-	dst->sin6_port = htons(1025);
-
-	if (inet_pton(AF_INET6, ip, &dst->sin6_addr) != 1) {
-		log_err("Invalid IPv6: %s", ip);
-		return -1;
-	}
-
-	dst->sin6_scope_id = if_nametoindex(iface);
-	if (!dst->sin6_scope_id) {
-		log_err("Failed to get index of iface: %s", iface);
-		return -1;
-	}
-
-	return 0;
-}
-
-static int send_packet(const char *iface)
-{
-	struct sockaddr_in6 dst;
-	char msg[] = "msg";
-	int err = 0;
-	int fd = -1;
-
-	if (mk_dst_addr(LINKLOCAL_MULTICAST, iface, &dst))
-		goto err;
-
-	fd = socket(AF_INET6, SOCK_DGRAM, 0);
-	if (fd == -1) {
-		log_err("Failed to create UDP socket");
-		goto err;
-	}
-
-	if (sendto(fd, &msg, sizeof(msg), 0, (const struct sockaddr *)&dst,
-		   sizeof(dst)) == -1) {
-		log_err("Failed to send datagram");
-		goto err;
-	}
-
-	goto out;
-err:
-	err = -1;
-out:
-	if (fd >= 0)
-		close(fd);
-	return err;
-}
-
-int get_map_fd_by_prog_id(int prog_id)
-{
-	struct bpf_prog_info info = {};
-	__u32 info_len = sizeof(info);
-	__u32 map_ids[1];
-	int prog_fd = -1;
-	int map_fd = -1;
-
-	prog_fd = bpf_prog_get_fd_by_id(prog_id);
-	if (prog_fd < 0) {
-		log_err("Failed to get fd by prog id %d", prog_id);
-		goto err;
-	}
-
-	info.nr_map_ids = 1;
-	info.map_ids = (__u64) (unsigned long) map_ids;
-
-	if (bpf_prog_get_info_by_fd(prog_fd, &info, &info_len)) {
-		log_err("Failed to get info by prog fd %d", prog_fd);
-		goto err;
-	}
-
-	if (!info.nr_map_ids) {
-		log_err("No maps found for prog fd %d", prog_fd);
-		goto err;
-	}
-
-	map_fd = bpf_map_get_fd_by_id(map_ids[0]);
-	if (map_fd < 0)
-		log_err("Failed to get fd by map id %d", map_ids[0]);
-err:
-	if (prog_fd >= 0)
-		close(prog_fd);
-	return map_fd;
-}
-
-int check_ancestor_cgroup_ids(int prog_id)
-{
-	__u64 actual_ids[NUM_CGROUP_LEVELS], expected_ids[NUM_CGROUP_LEVELS];
-	__u32 level;
-	int err = 0;
-	int map_fd;
-
-	expected_ids[0] = get_cgroup_id("/..");	/* root cgroup */
-	expected_ids[1] = get_cgroup_id("");
-	expected_ids[2] = get_cgroup_id(CGROUP_PATH);
-	expected_ids[3] = 0; /* non-existent cgroup */
-
-	map_fd = get_map_fd_by_prog_id(prog_id);
-	if (map_fd < 0)
-		goto err;
-
-	for (level = 0; level < NUM_CGROUP_LEVELS; ++level) {
-		if (bpf_map_lookup_elem(map_fd, &level, &actual_ids[level])) {
-			log_err("Failed to lookup key %d", level);
-			goto err;
-		}
-		if (actual_ids[level] != expected_ids[level]) {
-			log_err("%llx (actual) != %llx (expected), level: %u\n",
-				actual_ids[level], expected_ids[level], level);
-			goto err;
-		}
-	}
-
-	goto out;
-err:
-	err = -1;
-out:
-	if (map_fd >= 0)
-		close(map_fd);
-	return err;
-}
-
-int main(int argc, char **argv)
-{
-	int cgfd = -1;
-	int err = 0;
-
-	if (argc < 3) {
-		fprintf(stderr, "Usage: %s iface prog_id\n", argv[0]);
-		exit(EXIT_FAILURE);
-	}
-
-	/* Use libbpf 1.0 API mode */
-	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
-	cgfd = cgroup_setup_and_join(CGROUP_PATH);
-	if (cgfd < 0)
-		goto err;
-
-	if (send_packet(argv[1]))
-		goto err;
-
-	if (check_ancestor_cgroup_ids(atoi(argv[2])))
-		goto err;
-
-	goto out;
-err:
-	err = -1;
-out:
-	close(cgfd);
-	cleanup_cgroup_environment();
-	printf("[%s]\n", err ? "FAIL" : "PASS");
-	return err;
-}