[PATCH v2 bpf-next 14/14] samples/bpf: extend test_cgrp2_attach2 test to use cgroup storage

Roman Gushchin
2018-07-05T20:55:14Z

The test_cgrp2_attach test covers bpf cgroup attachment code well,
so let's re-use it for testing allocation/releasing of cgroup storage.

The extension is pretty straightforward: the bpf program will use
the cgroup storage to save the number of transmitted bytes.

Expected output:
$ ./test_cgrp2_attach2
Attached DROP prog. This ping in cgroup /foo should fail...
ping: sendmsg: Operation not permitted
Attached DROP prog. This ping in cgroup /foo/bar should fail...
ping: sendmsg: Operation not permitted
Attached PASS prog. This ping in cgroup /foo/bar should pass...
Detached PASS from /foo/bar while DROP is attached to /foo.
This ping in cgroup /foo/bar should fail...
ping: sendmsg: Operation not permitted
Attached PASS from /foo/bar and detached DROP from /foo.
This ping in cgroup /foo/bar should pass...
### override:PASS
### multi:PASS

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
samples/bpf/test_cgrp2_attach2.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/samples/bpf/test_cgrp2_attach2.c b/samples/bpf/test_cgrp2_attach2.c
index b453e6a161be..180f9d813bca 100644
--- a/samples/bpf/test_cgrp2_attach2.c
+++ b/samples/bpf/test_cgrp2_attach2.c
@@ -8,7 +8,8 @@
* information. The number of invocations of the program, which maps
* to the number of packets received, is stored to key 0. Key 1 is
* incremented on each iteration by the number of bytes stored in
- * the skb.
+ * the skb. The program also stores the number of received bytes
+ * in the cgroup storage.
*
* - Attaches the new program to a cgroup using BPF_PROG_ATTACH
*
@@ -21,12 +22,15 @@
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
+#include <sys/resource.h>
+#include <sys/time.h>
#include <unistd.h>

#include <linux/bpf.h>
#include <bpf/bpf.h>

#include "bpf_insn.h"
+#include "bpf_rlimit.h"
#include "cgroup_helpers.h"

#define FOO "/foo"
@@ -205,6 +209,8 @@ static int map_fd = -1;

static int prog_load_cnt(int verdict, int val)
{
+ int cgroup_storage_fd;
+
if (map_fd < 0)
map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 8, 1, 0);
if (map_fd < 0) {
@@ -212,6 +218,13 @@ static int prog_load_cnt(int verdict, int val)
return -1;
}

+ cgroup_storage_fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_STORAGE,
+ sizeof(struct bpf_cgroup_storage_key), 8, 0, 0);
+ if (cgroup_storage_fd < 0) {
+ printf("failed to create map '%s'\n", strerror(errno));
+ return -1;
+ }
+
struct bpf_insn prog[] = {
BPF_MOV32_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
@@ -222,6 +235,11 @@ static int prog_load_cnt(int verdict, int val)
BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_1, val), /* r1 = 1 */
BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
+ BPF_LD_MAP_FD(BPF_REG_1, cgroup_storage_fd),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_local_storage),
+ BPF_MOV64_IMM(BPF_REG_1, val),
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_W, BPF_REG_0, BPF_REG_1, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, verdict), /* r0 = verdict */
BPF_EXIT_INSN(),
};
@@ -237,6 +255,7 @@ static int prog_load_cnt(int verdict, int val)
printf("Output from verifier:\n%s\n-------\n", bpf_log_buf);
return 0;
}
+ close(cgroup_storage_fd);
return ret;
}

--
2.14.4