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author | Andrey Ignatov <rdna@fb.com> | 2019-03-23 15:51:00 -0700 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2019-04-12 13:54:59 -0700 |
commit | 7568f4cbbeae687e4c545516275479f50c15a7cc (patch) | |
tree | 6fd06f468a87e79e8c203969d90318b862159649 /tools/testing/selftests/bpf/progs/test_sysctl_prog.c | |
parent | 8549ddc832d6f36be47279d201e95cc8ade6faa9 (diff) | |
download | talos-op-linux-7568f4cbbeae687e4c545516275479f50c15a7cc.tar.gz talos-op-linux-7568f4cbbeae687e4c545516275479f50c15a7cc.zip |
selftests/bpf: C based test for sysctl and strtoX
Add C based test for a few bpf_sysctl_* helpers and bpf_strtoul.
Make sure that sysctl can be identified by name and that multiple
integers can be parsed from sysctl value with bpf_strtoul.
net/ipv4/tcp_mem is chosen as a testing sysctl, it contains 3 unsigned
longs, they all are parsed and compared (val[0] < val[1] < val[2]).
Example of output:
# ./test_sysctl
...
Test case: C prog: deny all writes .. [PASS]
Test case: C prog: deny access by name .. [PASS]
Test case: C prog: read tcp_mem .. [PASS]
Summary: 39 PASSED, 0 FAILED
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_sysctl_prog.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_sysctl_prog.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_sysctl_prog.c b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c new file mode 100644 index 000000000000..a295cad805d7 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook + +#include <stdint.h> +#include <string.h> + +#include <linux/stddef.h> +#include <linux/bpf.h> + +#include "bpf_helpers.h" +#include "bpf_util.h" + +/* Max supported length of a string with unsigned long in base 10 (pow2 - 1). */ +#define MAX_ULONG_STR_LEN 0xF + +/* Max supported length of sysctl value string (pow2). */ +#define MAX_VALUE_STR_LEN 0x40 + +static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx) +{ + char tcp_mem_name[] = "net/ipv4/tcp_mem"; + unsigned char i; + char name[64]; + int ret; + + memset(name, 0, sizeof(name)); + ret = bpf_sysctl_get_name(ctx, name, sizeof(name), 0); + if (ret < 0 || ret != sizeof(tcp_mem_name) - 1) + return 0; + +#pragma clang loop unroll(full) + for (i = 0; i < sizeof(tcp_mem_name); ++i) + if (name[i] != tcp_mem_name[i]) + return 0; + + return 1; +} + +SEC("cgroup/sysctl") +int sysctl_tcp_mem(struct bpf_sysctl *ctx) +{ + unsigned long tcp_mem[3] = {0, 0, 0}; + char value[MAX_VALUE_STR_LEN]; + unsigned char i, off = 0; + int ret; + + if (ctx->write) + return 0; + + if (!is_tcp_mem(ctx)) + return 0; + + ret = bpf_sysctl_get_current_value(ctx, value, MAX_VALUE_STR_LEN); + if (ret < 0 || ret >= MAX_VALUE_STR_LEN) + return 0; + +#pragma clang loop unroll(full) + for (i = 0; i < ARRAY_SIZE(tcp_mem); ++i) { + ret = bpf_strtoul(value + off, MAX_ULONG_STR_LEN, 0, + tcp_mem + i); + if (ret <= 0 || ret > MAX_ULONG_STR_LEN) + return 0; + off += ret & MAX_ULONG_STR_LEN; + } + + + return tcp_mem[0] < tcp_mem[1] && tcp_mem[1] < tcp_mem[2]; +} + +char _license[] SEC("license") = "GPL"; |