[PATCH bpf-next v4 4/4] selftests/bpf: convert test_skb_cgroup_id_user to test_progs

Alexis Lothoré (eBPF Foundation)
2024-08-13T12:45:22Z

test_skb_cgroup_id_user allows testing skb cgroup id retrieval at different
levels, but is not integrated in test_progs, so it is not run
automatically in CI. The test overlaps a bit with
cgroup_skb_sk_lookup_kern, which is integrated in test_progs and test
extensively skb cgroup helpers, but there is still one major difference
between the two tests which justifies the conversion:
cgroup_skb_sk_lookup_kern deals with a BPF_PROG_TYPE_CGROUP_SKB (attached
on a cgroup), while test_skb_cgroup_id_user deals with a
BPF_PROG_TYPE_SCHED_CLS (attached on a qdisc)

Convert test_skb_cgroup_id_user into test_progs framework in order to run
it automatically in CI. The main differences with the original test are the
following:
- rename the test to make it shorter and more straightforward regarding
tested feature
- the wrapping shell script has been dropped since every setup step is now
handled in the main C test file
- the test has been renamed for a shorter name and reflecting the tested
API
- add dedicated assert log per level to ease test failure debugging
- use global variables instead of maps to access bpf prog data

Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v3:
- close leaking socket
- close leaking cgroup file descriptor
- run test in dedicated network namespace

Changes in v2:
- use global variables instead of maps

The new test has been tested in a qemu environment:

./test_progs -a cgroup_ancestor
44 cgroup_ancestor:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
---
tools/testing/selftests/bpf/.gitignore | 1 -
tools/testing/selftests/bpf/Makefile | 3 +-
.../selftests/bpf/prog_tests/cgroup_ancestor.c | 169 +++++++++++++++++++
.../testing/selftests/bpf/progs/cgroup_ancestor.c | 12 +-
tools/testing/selftests/bpf/test_skb_cgroup_id.sh | 67 --------
.../selftests/bpf/test_skb_cgroup_id_user.c | 183 ---------------------
6 files changed, 172 insertions(+), 263 deletions(-)

diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index fd7ae37024e2..99ffea1fa5c6 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -19,7 +19,6 @@ test_sock
urandom_read
test_sockmap
test_lirc_mode2_user
-test_skb_cgroup_id_user
test_flow_dissector
flow_dissector_load
test_tcpnotify_user
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 29d689610ba2..b1259922d0aa 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -137,7 +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 \
@@ -290,7 +290,6 @@ 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)
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_ancestor.c b/tools/testing/selftests/bpf/prog_tests/cgroup_ancestor.c
new file mode 100644
index 000000000000..2965595cb166
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_ancestor.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "test_progs.h"
+#include "network_helpers.h"
+#include "cgroup_helpers.h"
+#include "cgroup_ancestor.skel.h"
+
+#define VETH_PREFIX "test_cgid_"
+#define VETH_1 VETH_PREFIX "1"
+#define VETH_2 VETH_PREFIX "2"
+#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 "ff02::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),
+ .sin6_scope_id = if_nametoindex(VETH_1) };
+ 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;
+
+ n = sendto(sock, buf, sizeof(buf), 0, (const struct sockaddr *)&addr,
+ sizeof(addr));
+ ASSERT_EQ(n, sizeof(buf), "send data");
+ close(sock);
+
+ return n == sizeof(buf) ? 0 : n;
+}
+
+static int wait_local_ip(void)
+{
+ char *ping_cmd = ping_command(AF_INET6);
+ int i, err;
+
+ for (i = 0; i < WAIT_AUTO_IP_MAX_ATTEMPT; i++) {
+ err = SYS_NOFAIL("%s -c 1 -W 1 %s%%%s", ping_cmd, DST_ADDR,
+ VETH_1);
+ if (!err)
+ break;
+ }
+
+ return err;
+}
+
+static int setup_network(struct test_data *t)
+{
+ int ret;
+
+ 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 add dev %s type veth peer name %s",
+ VETH_1, VETH_2);
+ SYS(close_ns, "ip link set %s up", VETH_1);
+ SYS(close_ns, "ip link set %s up", VETH_2);
+
+ ret = wait_local_ip();
+ if (!ASSERT_EQ(ret, 0, "wait local ip"))
+ goto cleanup_interfaces;
+
+ 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(VETH_1);
+ if (!ASSERT_NEQ(t->qdisc.ifindex, 0, "if_nametoindex"))
+ goto cleanup_interfaces;
+ if (!ASSERT_OK(bpf_tc_hook_create(&t->qdisc), "qdisc add"))
+ goto cleanup_interfaces;
+
+ 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);
+cleanup_interfaces:
+ SYS_NOFAIL("ip link del %s", VETH_1);
+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);
+ /* Deleting first interface will also delete peer interface */
+ SYS_NOFAIL("ip link del %s", VETH_1);
+ 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;
+
+ 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);
+}
diff --git a/tools/testing/selftests/bpf/progs/cgroup_ancestor.c b/tools/testing/selftests/bpf/progs/cgroup_ancestor.c
index 4879645f5827..23c2e63e77a2 100644
--- a/tools/testing/selftests/bpf/progs/cgroup_ancestor.c
+++ b/tools/testing/selftests/bpf/progs/cgroup_ancestor.c
@@ -10,22 +10,14 @@

#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];

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("tc")
diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id.sh b/tools/testing/selftests/bpf/test_skb_cgroup_id.sh
deleted file mode 100755
index d7dad49175c2..000000000000
--- a/tools/testing/selftests/bpf/test_skb_cgroup_id.sh
+++ /dev/null
@@ -1,67 +0,0 @@
-#!/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 ${TEST_IF} clsact
- mkdir -p /sys/fs/bpf/${BPF_PROG_PIN}
- bpftool prog loadall ${BPF_PROG_OBJ} /sys/fs/bpf/${BPF_PROG_PIN} type tc
- tc filter add dev ${TEST_IF} egress bpf da object-pinned \
- /sys/fs/bpf/${BPF_PROG_PIN}/${BPF_PROG_NAME}
-
- BPF_PROG_ID=$(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 ${TEST_IF_PEER} 2>/dev/null || :
- rm -rf /sys/fs/bpf/${BPF_PROG_PIN}
-}
-
-main()
-{
- trap cleanup EXIT 2 3 6 15
- setup
- ${PROG} ${TEST_IF} ${BPF_PROG_ID}
-}
-
-DIR=$(dirname $0)
-TEST_IF="test_cgid_1"
-TEST_IF_PEER="test_cgid_2"
-MAX_PING_TRIES=5
-BPF_PROG_PIN="cgroup_ancestor"
-BPF_PROG_OBJ="${DIR}/${BPF_PROG_PIN}.bpf.o"
-BPF_PROG_NAME="log_cgroup_id"
-BPF_PROG_ID=0
-PROG="${DIR}/test_skb_cgroup_id_user"
-type ping6 >/dev/null 2>&1 && PING6="ping6" || PING6="ping -6"
-
-main
diff --git a/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c b/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c
deleted file mode 100644
index ed518d075d1d..000000000000
--- a/tools/testing/selftests/bpf/test_skb_cgroup_id_user.c
+++ /dev/null
@@ -1,183 +0,0 @@
-// 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;
-}

--
2.46.0