netdev - Re: [RFC PATCH v1 3/3] test/vsock: skbuff merging test

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Date:   Mon, 20 Mar 2023 21:12:48 +0300
From:   Arseniy Krasnov <avkrasnov@...rdevices.ru>
To:     Stefano Garzarella <sgarzare@...hat.com>
CC:     Stefan Hajnoczi <stefanha@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Bobby Eshleman <bobby.eshleman@...edance.com>,
        <kvm@...r.kernel.org>, <virtualization@...ts.linux-foundation.org>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <kernel@...rdevices.ru>, <oxffffaa@...il.com>
Subject: Re: [RFC PATCH v1 3/3] test/vsock: skbuff merging test



On 20.03.2023 18:31, Stefano Garzarella wrote:
> On Sun, Mar 19, 2023 at 09:53:54PM +0300, Arseniy Krasnov wrote:
>> This adds test which checks case when data of newly received skbuff is
>> appended to the last skbuff in the socket's queue.
>>
>> This test is actual only for virtio transport.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>> ---
>> tools/testing/vsock/vsock_test.c | 81 ++++++++++++++++++++++++++++++++
>> 1 file changed, 81 insertions(+)
>>
>> diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
>> index 3de10dbb50f5..00216c52d8b6 100644
>> --- a/tools/testing/vsock/vsock_test.c
>> +++ b/tools/testing/vsock/vsock_test.c
>> @@ -968,6 +968,82 @@ static void test_seqpacket_inv_buf_server(const struct test_opts *opts)
>>     test_inv_buf_server(opts, false);
>> }
>>
>> +static void test_stream_virtio_skb_merge_client(const struct test_opts *opts)
>> +{
>> +    ssize_t res;
>> +    int fd;
>> +
>> +    fd = vsock_stream_connect(opts->peer_cid, 1234);
>> +    if (fd < 0) {
>> +        perror("connect");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
> 
> Please use a macro for "HELLO" or a variabile, e.g.
> 
>         char *buf;
>         ...
> 
>         buf = "HELLO";
>         res = send(fd, buf, strlen(buf), 0);
>         ...
> 
>> +    res = send(fd, "HELLO", strlen("HELLO"), 0);
>> +    if (res != strlen("HELLO")) {
>> +        fprintf(stderr, "unexpected send(2) result %zi\n", res);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_writeln("SEND0");
>> +    /* Peer reads part of first packet. */
>> +    control_expectln("REPLY0");
>> +
>> +    /* Send second skbuff, it will be merged. */
>> +    res = send(fd, "WORLD", strlen("WORLD"), 0);
> 
> Ditto.
> 
>> +    if (res != strlen("WORLD")) {
>> +        fprintf(stderr, "unexpected send(2) result %zi\n", res);
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_writeln("SEND1");
>> +    /* Peer reads merged skbuff packet. */
>> +    control_expectln("REPLY1");
>> +
>> +    close(fd);
>> +}
>> +
>> +static void test_stream_virtio_skb_merge_server(const struct test_opts *opts)
>> +{
>> +    unsigned char buf[64];
>> +    ssize_t res;
>> +    int fd;
>> +
>> +    fd = vsock_stream_accept(VMADDR_CID_ANY, 1234, NULL);
>> +    if (fd < 0) {
>> +        perror("accept");
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_expectln("SEND0");
>> +
>> +    /* Read skbuff partially. */
>> +    res = recv(fd, buf, 2, 0);
>> +    if (res != 2) {
>> +        fprintf(stderr, "expected recv(2) failure, got %zi\n", res);
> 
> We don't expect a failure, so please update the error message and make
> it easy to figure out which recv() is failing. For example by saying
> how many bytes you expected and how many you received.
> 
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    control_writeln("REPLY0");
>> +    control_expectln("SEND1");
>> +
>> +
>> +    res = recv(fd, buf, sizeof(buf), 0);
> 
> Perhaps a comment here to explain why we expect only 8 bytes.
> 
>> +    if (res != 8) {
>> +        fprintf(stderr, "expected recv(2) failure, got %zi\n", res);
> 
> Ditto.
> 
>> +        exit(EXIT_FAILURE);
>> +    }
>> +
>> +    res = recv(fd, buf, sizeof(buf), MSG_DONTWAIT);
>> +    if (res != -1) {
>> +        fprintf(stderr, "expected recv(2) success, got %zi\n", res);
> 
> It's the other way around, isn't it?
> Here you expect it to fail instead it is not failing.
> 
>> +        exit(EXIT_FAILURE);
>> +    }
> 
> Moving the pointer correctly, I would also check that there is
> HELLOWORLD in the buffer.
> 
> Thanks for adding tests in this suite!
> Stefano

Thanks for review, i didn't pay any attention on this test, because it is
just bug reproducer. But if we are going to add it, of course i'll clean
it's code.

Thanks, Arseniy

> 
>> +
>> +    control_writeln("REPLY1");
>> +
>> +    close(fd);
>> +}
>> +
>> static struct test_case test_cases[] = {
>>     {
>>         .name = "SOCK_STREAM connection reset",
>> @@ -1038,6 +1114,11 @@ static struct test_case test_cases[] = {
>>         .run_client = test_seqpacket_inv_buf_client,
>>         .run_server = test_seqpacket_inv_buf_server,
>>     },
>> +    {
>> +        .name = "SOCK_STREAM virtio skb merge",
>> +        .run_client = test_stream_virtio_skb_merge_client,
>> +        .run_server = test_stream_virtio_skb_merge_server,
>> +    },
>>     {},
>> };
>>
>> -- 
>> 2.25.1
>>
>