selftests/bpf: Move netcnt test under test_progs

Rewrite to skel and ASSERT macros as well while we are at it.

v3:
- replace -f with -A to make it work with busybox ping.
  -A is available on both busybox and iputils, from the man page:
  On networks with low RTT this mode is essentially equivalent to
  flood mode.

v2:
- don't check result of bpf_map__fd (Yonghong Song)
- remove from .gitignore (Andrii Nakryiko)
- move ping_command into network_helpers (Andrii Nakryiko)
- remove assert() (Andrii Nakryiko)

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210804205524.3748709-1-sdf@google.com

tools/testing/selftests/bpf/.gitignore

@@ -23,7 +23,6 @@ test_skb_cgroup_id_user
 test_cgroup_storage
 test_flow_dissector
 flow_dissector_load
-test_netcnt
 test_tcpnotify_user
 test_libbpf
 test_tcp_check_syncookie_user

tools/testing/selftests/bpf/Makefile

@@ -38,7 +38,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
 	test_verifier_log test_dev_cgroup \
 	test_sock test_sockmap get_cgroup_id_user \
 	test_cgroup_storage \
-	test_netcnt test_tcpnotify_user test_sysctl \
+	test_tcpnotify_user test_sysctl \
 	test_progs-no_alu32
 
 # Also test bpf-gcc, if present
@@ -197,7 +197,6 @@ $(OUTPUT)/test_sockmap: cgroup_helpers.c
 $(OUTPUT)/test_tcpnotify_user: cgroup_helpers.c trace_helpers.c
 $(OUTPUT)/get_cgroup_id_user: cgroup_helpers.c
 $(OUTPUT)/test_cgroup_storage: cgroup_helpers.c
-$(OUTPUT)/test_netcnt: cgroup_helpers.c
 $(OUTPUT)/test_sock_fields: cgroup_helpers.c
 $(OUTPUT)/test_sysctl: cgroup_helpers.c
 

tools/testing/selftests/bpf/network_helpers.c

@@ -310,3 +310,15 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
 	}
 	return -1;
 }
+
+char *ping_command(int family)
+{
+	if (family == AF_INET6) {
+		/* On some systems 'ping' doesn't support IPv6, so use ping6 if it is present. */
+		if (!system("which ping6 >/dev/null 2>&1"))
+			return "ping6";
+		else
+			return "ping -6";
+	}
+	return "ping";
+}

tools/testing/selftests/bpf/network_helpers.h

@@ -46,5 +46,6 @@ int fastopen_connect(int server_fd, const char *data, unsigned int data_len,
 		     int timeout_ms);
 int make_sockaddr(int family, const char *addr_str, __u16 port,
 		  struct sockaddr_storage *addr, socklen_t *len);
+char *ping_command(int family);
 
 #endif

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

@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <sys/sysinfo.h>
+#include <test_progs.h>
+#include "network_helpers.h"
+#include "netcnt_prog.skel.h"
+#include "netcnt_common.h"
+
+#define CG_NAME "/netcnt"
+
+void test_netcnt(void)
+{
+	union percpu_net_cnt *percpu_netcnt = NULL;
+	struct bpf_cgroup_storage_key key;
+	int map_fd, percpu_map_fd;
+	struct netcnt_prog *skel;
+	unsigned long packets;
+	union net_cnt netcnt;
+	unsigned long bytes;
+	int cpu, nproc;
+	int cg_fd = -1;
+	char cmd[128];
+
+	skel = netcnt_prog__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "netcnt_prog__open_and_load"))
+		return;
+
+	nproc = get_nprocs_conf();
+	percpu_netcnt = malloc(sizeof(*percpu_netcnt) * nproc);
+	if (!ASSERT_OK_PTR(percpu_netcnt, "malloc(percpu_netcnt)"))
+		goto err;
+
+	cg_fd = test__join_cgroup(CG_NAME);
+	if (!ASSERT_GE(cg_fd, 0, "test__join_cgroup"))
+		goto err;
+
+	skel->links.bpf_nextcnt = bpf_program__attach_cgroup(skel->progs.bpf_nextcnt, cg_fd);
+	if (!ASSERT_OK_PTR(skel->links.bpf_nextcnt,
+			   "attach_cgroup(bpf_nextcnt)"))
+		goto err;
+
+	snprintf(cmd, sizeof(cmd), "%s ::1 -A -c 10000 -q > /dev/null", ping_command(AF_INET6));
+	ASSERT_OK(system(cmd), cmd);
+
+	map_fd = bpf_map__fd(skel->maps.netcnt);
+	if (!ASSERT_OK(bpf_map_get_next_key(map_fd, NULL, &key), "bpf_map_get_next_key"))
+		goto err;
+
+	if (!ASSERT_OK(bpf_map_lookup_elem(map_fd, &key, &netcnt), "bpf_map_lookup_elem(netcnt)"))
+		goto err;
+
+	percpu_map_fd = bpf_map__fd(skel->maps.percpu_netcnt);
+	if (!ASSERT_OK(bpf_map_lookup_elem(percpu_map_fd, &key, &percpu_netcnt[0]),
+		       "bpf_map_lookup_elem(percpu_netcnt)"))
+		goto err;
+
+	/* Some packets can be still in per-cpu cache, but not more than
+	 * MAX_PERCPU_PACKETS.
+	 */
+	packets = netcnt.packets;
+	bytes = netcnt.bytes;
+	for (cpu = 0; cpu < nproc; cpu++) {
+		ASSERT_LE(percpu_netcnt[cpu].packets, MAX_PERCPU_PACKETS, "MAX_PERCPU_PACKETS");
+
+		packets += percpu_netcnt[cpu].packets;
+		bytes += percpu_netcnt[cpu].bytes;
+	}
+
+	/* No packets should be lost */
+	ASSERT_EQ(packets, 10000, "packets");
+
+	/* Let's check that bytes counter matches the number of packets
+	 * multiplied by the size of ipv6 ICMP packet.
+	 */
+	ASSERT_EQ(bytes, packets * 104, "bytes");
+
+err:
+	if (cg_fd != -1)
+		close(cg_fd);
+	free(percpu_netcnt);
+	netcnt_prog__destroy(skel);
+}

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

@@ -390,18 +390,6 @@ static void test_tcp(int family, const char *addr, __u16 port)
 		close(client_fd);
 }
 
-static char *ping_command(int family)
-{
-	if (family == AF_INET6) {
-		/* On some systems 'ping' doesn't support IPv6, so use ping6 if it is present. */
-		if (!system("which ping6 >/dev/null 2>&1"))
-			return "ping6";
-		else
-			return "ping -6";
-	}
-	return "ping";
-}
-
 static int test_ping(int family, const char *addr)
 {
 	SYS("ip netns exec " NS_SRC " %s " PING_ARGS " %s > /dev/null", ping_command(family), addr);