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SubjectRe: [RFC PATCH v1 1/3] test/vsock: rework message bound test
On Mon, Nov 21, 2022 at 04:49:23PM +0000, Arseniy Krasnov wrote:
>On 21.11.2022 17:46, Stefano Garzarella wrote:
>> On Tue, Nov 15, 2022 at 08:50:36PM +0000, Arseniy Krasnov wrote:
>>> This updates message bound test making it more complex. Instead of
>>> sending 1 bytes messages with one MSG_EOR bit, it sends messages of
>>> random length(one half of messages are smaller than page size, second
>>> half are bigger) with random number of MSG_EOR bits set. Receiver
>>> also don't know total number of messages.
>>>
>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>>> ---
>>> tools/testing/vsock/control.c    |  34 +++++++++
>>> tools/testing/vsock/control.h    |   2 +
>>> tools/testing/vsock/util.c       |  13 ++++
>>> tools/testing/vsock/util.h       |   1 +
>>> tools/testing/vsock/vsock_test.c | 115 +++++++++++++++++++++++++++----
>>> 5 files changed, 152 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/tools/testing/vsock/control.c b/tools/testing/vsock/control.c
>>> index 4874872fc5a3..bed1649bdf3d 100644
>>> --- a/tools/testing/vsock/control.c
>>> +++ b/tools/testing/vsock/control.c
>>> @@ -141,6 +141,40 @@ void control_writeln(const char *str)
>>>     timeout_end();
>>> }
>>>
>>> +void control_writeulong(unsigned long value)
>>> +{
>>> +    char str[32];
>>> +
>>> +    if (snprintf(str, sizeof(str), "%lu", value) >= sizeof(str)) {
>>> +        perror("snprintf");
>>> +        exit(EXIT_FAILURE);
>>> +    }
>>> +
>>> +    control_writeln(str);
>>> +}
>>> +
>>> +unsigned long control_readulong(bool *ok)
>>> +{
>>> +    unsigned long value;
>>> +    char *str;
>>> +
>>> +    if (ok)
>>> +        *ok = false;
>>> +
>>> +    str = control_readln();
>>> +
>>> +    if (str == NULL)
>>
>> checkpatch suggests to use !str
>>
>>> +        return 0;
>>
>> Maybe we can just call exit(EXIT_FAILURE) here and remove the `ok`
>> parameter, since I'm not sure we can recover from this error.
>>
>>> +
>>> +    value = strtoul(str, NULL, 10);
>>> +    free(str);
>>> +
>>> +    if (ok)
>>> +        *ok = true;
>>> +
>>> +    return value;
>>> +}
>>> +
>>> /* Return the next line from the control socket (without the trailing newline).
>>>  *
>>>  * The program terminates if a timeout occurs.
>>> diff --git a/tools/testing/vsock/control.h b/tools/testing/vsock/control.h
>>> index 51814b4f9ac1..cdd922dfea68 100644
>>> --- a/tools/testing/vsock/control.h
>>> +++ b/tools/testing/vsock/control.h
>>> @@ -9,7 +9,9 @@ void control_init(const char *control_host, const char *control_port,
>>> void control_cleanup(void);
>>> void control_writeln(const char *str);
>>> char *control_readln(void);
>>> +unsigned long control_readulong(bool *ok);
>>> void control_expectln(const char *str);
>>> bool control_cmpln(char *line, const char *str, bool fail);
>>> +void control_writeulong(unsigned long value);
>>>
>>> #endif /* CONTROL_H */
>>> diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
>>> index 2acbb7703c6a..351903836774 100644
>>> --- a/tools/testing/vsock/util.c
>>> +++ b/tools/testing/vsock/util.c
>>> @@ -395,3 +395,16 @@ void skip_test(struct test_case *test_cases, size_t test_cases_len,
>>>
>>>     test_cases[test_id].skip = true;
>>> }
>>> +
>>> +unsigned long djb2(const void *data, size_t len)
>>
>> I would add hash_ as a prefix (or suffix).
>>
>>> +{
>>> +    unsigned long hash = 5381;
>>> +    int i = 0;
>>> +
>>> +    while (i < len) {
>>> +        hash = ((hash << 5) + hash) + ((unsigned char *)data)[i];
>>> +        i++;
>>> +    }
>>> +
>>> +    return hash;
>>> +}
>>> diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
>>> index a3375ad2fb7f..988cc69a4642 100644
>>> --- a/tools/testing/vsock/util.h
>>> +++ b/tools/testing/vsock/util.h
>>> @@ -49,4 +49,5 @@ void run_tests(const struct test_case *test_cases,
>>> void list_tests(const struct test_case *test_cases);
>>> void skip_test(struct test_case *test_cases, size_t test_cases_len,
>>>            const char *test_id_str);
>>> +unsigned long djb2(const void *data, size_t len);
>>> #endif /* UTIL_H */
>>> diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>>> index bb6d691cb30d..107c11165887 100644
>>> --- a/tools/testing/vsock/vsock_test.c
>>> +++ b/tools/testing/vsock/vsock_test.c
>>> @@ -284,10 +284,14 @@ static void test_stream_msg_peek_server(const struct test_opts *opts)
>>>     close(fd);
>>> }
>>>
>>> -#define MESSAGES_CNT 7
>>> -#define MSG_EOR_IDX (MESSAGES_CNT / 2)
>>> +#define SOCK_BUF_SIZE (2 * 1024 * 1024)
>>> +#define MAX_MSG_SIZE (32 * 1024)
>>> +
>>> static void test_seqpacket_msg_bounds_client(const struct test_opts *opts)
>>> {
>>> +    unsigned long curr_hash;
>>> +    int page_size;
>>> +    int msg_count;
>>>     int fd;
>>>
>>>     fd = vsock_seqpacket_connect(opts->peer_cid, 1234);
>>> @@ -296,18 +300,69 @@ static void test_seqpacket_msg_bounds_client(const struct test_opts *opts)
>>>         exit(EXIT_FAILURE);
>>>     }
>>>
>>> -    /* Send several messages, one with MSG_EOR flag */
>>> -    for (int i = 0; i < MESSAGES_CNT; i++)
>>> -        send_byte(fd, 1, (i == MSG_EOR_IDX) ? MSG_EOR : 0);
>>> +    /* Wait, until receiver sets buffer size. */
>>> +    control_expectln("SRVREADY");
>>> +
>>> +    curr_hash = 0;
>>> +    page_size = getpagesize();
>>> +    msg_count = SOCK_BUF_SIZE / MAX_MSG_SIZE;
>>> +
>>> +    for (int i = 0; i < msg_count; i++) {
>>> +        ssize_t send_size;
>>> +        size_t buf_size;
>>> +        int flags;
>>> +        void *buf;
>>> +
>>> +        /* Use "small" buffers and "big" buffers. */
>>> +        if (i & 1)
>>> +            buf_size = page_size +
>>> +                    (rand() % (MAX_MSG_SIZE - page_size));
>>> +        else
>>> +            buf_size = 1 + (rand() % page_size);
>>> +
>>> +        buf = malloc(buf_size);
>>> +
>>> +        if (!buf) {
>>> +            perror("malloc");
>>> +            exit(EXIT_FAILURE);
>>> +        }
>>> +
>>> +        /* Set at least one MSG_EOR + some random. */
>>> +        if (i == (msg_count / 2) || (rand() & 1)) {
>>> +            flags = MSG_EOR;
>>> +            curr_hash++;
>>> +        } else {
>>> +            flags = 0;
>>> +        }
>>> +
>>> +        send_size = send(fd, buf, buf_size, flags);
>>> +
>>> +        if (send_size < 0) {
>>> +            perror("send");
>>> +            exit(EXIT_FAILURE);
>>> +        }
>>> +
>>> +        if (send_size != buf_size) {
>>> +            fprintf(stderr, "Invalid send size\n");
>>> +            exit(EXIT_FAILURE);
>>> +        }
>>> +
>>> +        curr_hash += send_size;
>>> +        curr_hash = djb2(&curr_hash, sizeof(curr_hash));
>>> +    }
>>>
>>>     control_writeln("SENDDONE");
>>> +    control_writeulong(curr_hash);
>>
>> Why do we need to hash the size?
>>
>> Maybe we can send it without making the hash, anyway even if it wraps,
>> it should wrap the same way in both the server and the client.
>> (Or maybe we can use uin32_t or uint64_t to make sure both were
>> using 4 or 8 bytes)
>Hello, thanks for review. I think if we will use sum of message size(IIUC), in most
>paranoic case it won't guarantee message bounds control: single 4 bytes message
>could be read as 4 x 1 byte message(IIUC of course). Idea of hashing is simple:
>every iteration we do current_hash = hash(previous_hash + size of current message);
>I think this is more reliable and protects from case described above.

Okay, now I understand what it is for and agree that using hash is
better.
Please add a comment to explain it.

>
>All other comments - ack.

Thanks,
Stefano

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