Example #1
0
void test_plain_vanilla_socket ()
{
    // Unauthenticated messages from a vanilla socket shouldn't be received
    struct sockaddr_in ip4addr;
    fd_t s;

    unsigned short int port;
    int rc = sscanf (my_endpoint, "tcp://127.0.0.1:%hu", &port);
    TEST_ASSERT_EQUAL_INT (1, rc);

    ip4addr.sin_family = AF_INET;
    ip4addr.sin_port = htons (port);
#if defined(ZMQ_HAVE_WINDOWS) && (_WIN32_WINNT < 0x0600)
    ip4addr.sin_addr.s_addr = inet_addr ("127.0.0.1");
#else
    inet_pton (AF_INET, "127.0.0.1", &ip4addr.sin_addr);
#endif

    s = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
    rc = connect (s, (struct sockaddr *) &ip4addr, sizeof (ip4addr));
    TEST_ASSERT_GREATER_THAN_INT (-1, rc);
    // send anonymous ZMTP/1.0 greeting
    send (s, "\x01\x00", 2, 0);
    // send sneaky message that shouldn't be received
    send (s, "\x08\x00sneaky\0", 9, 0);
    int timeout = 250;
    zmq_setsockopt (server, ZMQ_RCVTIMEO, &timeout, sizeof (timeout));
    char *buf = s_recv (server);
    if (buf != NULL) {
        printf ("Received unauthenticated message: %s\n", buf);
        TEST_ASSERT_NULL (buf);
    }
    close (s);
}
Example #2
0
static void recv_with_retry (raw_socket fd_, char *buffer_, int bytes_)
{
    int received = 0;
    while (true) {
        int rc = TEST_ASSERT_SUCCESS_RAW_ERRNO (
          recv (fd_, buffer_ + received, bytes_ - received, 0));
        TEST_ASSERT_GREATER_THAN_INT (0, rc);
        received += rc;
        TEST_ASSERT_LESS_OR_EQUAL_INT (bytes_, received);
        if (received == bytes_)
            break;
    }
}
Example #3
0
// This checks for a broken TCP connection (or, in this case a stuck one
// where the peer never responds to PINGS). There should be an accepted event
// then a disconnect event.
static void test_heartbeat_timeout (int server_type_, int mock_ping_)
{
    int rc;
    char my_endpoint[MAX_SOCKET_STRING];

    void *server, *server_mon;
    prep_server_socket (!mock_ping_, 0, &server, &server_mon, my_endpoint,
                        MAX_SOCKET_STRING, server_type_);

    struct sockaddr_in ip4addr;
    raw_socket s;

    ip4addr.sin_family = AF_INET;
    ip4addr.sin_port = htons (atoi (strrchr (my_endpoint, ':') + 1));
#if defined(ZMQ_HAVE_WINDOWS) && (_WIN32_WINNT < 0x0600)
    ip4addr.sin_addr.s_addr = inet_addr ("127.0.0.1");
#else
    inet_pton (AF_INET, "127.0.0.1", &ip4addr.sin_addr);
#endif

    s = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
    rc = TEST_ASSERT_SUCCESS_RAW_ERRNO (
      connect (s, (struct sockaddr *) &ip4addr, sizeof ip4addr));
    TEST_ASSERT_GREATER_THAN_INT (-1, rc);

    // Mock a ZMTP 3 client so we can forcibly time out a connection
    mock_handshake (s, mock_ping_);

    // By now everything should report as connected
    rc = get_monitor_event (server_mon);
    TEST_ASSERT_EQUAL_INT (ZMQ_EVENT_ACCEPTED, rc);

    if (!mock_ping_) {
        // We should have been disconnected
        rc = get_monitor_event (server_mon);
        TEST_ASSERT_EQUAL_INT (ZMQ_EVENT_DISCONNECTED, rc);
    }

    close (s);

    test_context_socket_close (server);
    test_context_socket_close (server_mon);
}
Example #4
0
static void test_stream_to_dealer ()
{
    int rc;
    char my_endpoint[MAX_SOCKET_STRING];

    //  We'll be using this socket in raw mode
    void *stream = test_context_socket (ZMQ_STREAM);

    int zero = 0;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (stream, ZMQ_LINGER, &zero, sizeof (zero)));
    int enabled = 1;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (stream, ZMQ_STREAM_NOTIFY, &enabled, sizeof (enabled)));
    bind_loopback_ipv4 (stream, my_endpoint, sizeof my_endpoint);

    //  We'll be using this socket as the other peer
    void *dealer = test_context_socket (ZMQ_DEALER);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer, ZMQ_LINGER, &zero, sizeof (zero)));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer, my_endpoint));

    //  Send a message on the dealer socket
    send_string_expect_success (dealer, "Hello", 0);

    //  Connecting sends a zero message
    //  First frame is routing id
    zmq_msg_t routing_id;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&routing_id));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&routing_id, stream, 0));
    TEST_ASSERT_TRUE (zmq_msg_more (&routing_id));

    //  Verify the existence of Peer-Address metadata
    char const *peer_address = zmq_msg_gets (&routing_id, "Peer-Address");
    TEST_ASSERT_NOT_NULL (peer_address);
    TEST_ASSERT_EQUAL_STRING ("127.0.0.1", peer_address);

    //  Second frame is zero
    byte buffer[255];
    TEST_ASSERT_EQUAL_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (stream, buffer, 255, 0)));

    //  Verify the existence of Peer-Address metadata
    peer_address = zmq_msg_gets (&routing_id, "Peer-Address");
    TEST_ASSERT_NOT_NULL (peer_address);
    TEST_ASSERT_EQUAL_STRING ("127.0.0.1", peer_address);

    //  Real data follows
    //  First frame is routing id
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&routing_id, stream, 0));
    TEST_ASSERT_TRUE (zmq_msg_more (&routing_id));

    //  Verify the existence of Peer-Address metadata
    peer_address = zmq_msg_gets (&routing_id, "Peer-Address");
    TEST_ASSERT_NOT_NULL (peer_address);
    TEST_ASSERT_EQUAL_STRING ("127.0.0.1", peer_address);

    //  Second frame is greeting signature
    recv_array_expect_success (stream, greeting.signature, 0);

    //  Send our own protocol greeting
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_send (&routing_id, stream, ZMQ_SNDMORE));
    TEST_ASSERT_EQUAL_INT (
      sizeof (greeting), TEST_ASSERT_SUCCESS_ERRNO (
                           zmq_send (stream, &greeting, sizeof (greeting), 0)));

    //  Now we expect the data from the DEALER socket
    //  We want the rest of greeting along with the Ready command
    int bytes_read = 0;
    while (bytes_read < 97) {
        //  First frame is the routing id of the connection (each time)
        TEST_ASSERT_GREATER_THAN_INT (
          0, TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&routing_id, stream, 0)));
        TEST_ASSERT_TRUE (zmq_msg_more (&routing_id));
        //  Second frame contains the next chunk of data
        TEST_ASSERT_SUCCESS_ERRNO (
          rc = zmq_recv (stream, buffer + bytes_read, 255 - bytes_read, 0));
        bytes_read += rc;
    }

    //  First two bytes are major and minor version numbers.
    TEST_ASSERT_EQUAL_INT (3, buffer[0]); //  ZMTP/3.0
    TEST_ASSERT_EQUAL_INT (0, buffer[1]);

    //  Mechanism is "NULL"
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer + 2,
                                  "NULL\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 20);
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer + 54, "\4\51\5READY", 8);
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer + 62, "\13Socket-Type\0\0\0\6DEALER",
                                  22);
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer + 84, "\10Identity\0\0\0\0", 13);

    //  Announce we are ready
    memcpy (buffer, "\4\51\5READY", 8);
    memcpy (buffer + 8, "\13Socket-Type\0\0\0\6ROUTER", 22);
    memcpy (buffer + 30, "\10Identity\0\0\0\0", 13);

    //  Send Ready command
    TEST_ASSERT_GREATER_THAN_INT (0, TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_send (
                                       &routing_id, stream, ZMQ_SNDMORE)));
    TEST_ASSERT_EQUAL_INT (
      43, TEST_ASSERT_SUCCESS_ERRNO (zmq_send (stream, buffer, 43, 0)));

    //  Now we expect the data from the DEALER socket
    //  First frame is, again, the routing id of the connection
    TEST_ASSERT_GREATER_THAN_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&routing_id, stream, 0)));
    TEST_ASSERT_TRUE (zmq_msg_more (&routing_id));

    //  Third frame contains Hello message from DEALER
    TEST_ASSERT_EQUAL_INT (7, TEST_ASSERT_SUCCESS_ERRNO (
                                zmq_recv (stream, buffer, sizeof buffer, 0)));

    //  Then we have a 5-byte message "Hello"
    TEST_ASSERT_EQUAL_INT (0, buffer[0]); //  Flags = 0
    TEST_ASSERT_EQUAL_INT (5, buffer[1]); //  Size = 5
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer + 2, "Hello", 5);

    //  Send "World" back to DEALER
    TEST_ASSERT_GREATER_THAN_INT (0, TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_send (
                                       &routing_id, stream, ZMQ_SNDMORE)));
    byte world[] = {0, 5, 'W', 'o', 'r', 'l', 'd'};
    TEST_ASSERT_EQUAL_INT (
      sizeof (world),
      TEST_ASSERT_SUCCESS_ERRNO (zmq_send (stream, world, sizeof (world), 0)));

    //  Expect response on DEALER socket
    recv_string_expect_success (dealer, "World", 0);

    //  Test large messages over STREAM socket
#define size 64000
    uint8_t msgout[size];
    memset (msgout, 0xAB, size);
    zmq_send (dealer, msgout, size, 0);

    uint8_t msgin[9 + size];
    memset (msgin, 0, 9 + size);
    bytes_read = 0;
    while (bytes_read < 9 + size) {
        //  Get routing id frame
        TEST_ASSERT_GREATER_THAN_INT (
          0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (stream, buffer, 256, 0)));
        //  Get next chunk
        TEST_ASSERT_GREATER_THAN_INT (
          0,
          TEST_ASSERT_SUCCESS_ERRNO (rc = zmq_recv (stream, msgin + bytes_read,
                                                    9 + size - bytes_read, 0)));
        bytes_read += rc;
    }
    for (int byte_nbr = 0; byte_nbr < size; byte_nbr++) {
        TEST_ASSERT_EQUAL_UINT8 (0xAB, msgin[9 + byte_nbr]);
    }
    test_context_socket_close (dealer);
    test_context_socket_close (stream);
}
Example #5
0
static void test_stream_to_stream ()
{
    char my_endpoint[MAX_SOCKET_STRING];
    //  Set-up our context and sockets

    void *server = test_context_socket (ZMQ_STREAM);
    int enabled = 1;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (server, ZMQ_STREAM_NOTIFY, &enabled, sizeof (enabled)));
    bind_loopback_ipv4 (server, my_endpoint, sizeof my_endpoint);

    void *client = test_context_socket (ZMQ_STREAM);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (client, ZMQ_STREAM_NOTIFY, &enabled, sizeof (enabled)));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (client, my_endpoint));
    uint8_t id[256];
    uint8_t buffer[256];

    //  Connecting sends a zero message
    //  Server: First frame is routing id, second frame is zero
    TEST_ASSERT_GREATER_THAN_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (server, id, 256, 0)));
    TEST_ASSERT_EQUAL_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (server, buffer, 256, 0)));
    //  Client: First frame is routing id, second frame is zero
    TEST_ASSERT_GREATER_THAN_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (client, id, 256, 0)));
    TEST_ASSERT_EQUAL_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (client, buffer, 256, 0)));

    //  Sent HTTP request on client socket
    //  Get server routing id
    size_t id_size = sizeof id;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_getsockopt (client, ZMQ_ROUTING_ID, id, &id_size));
    //  First frame is server routing id
    TEST_ASSERT_EQUAL_INT ((int) id_size, TEST_ASSERT_SUCCESS_ERRNO (zmq_send (
                                            client, id, id_size, ZMQ_SNDMORE)));
    //  Second frame is HTTP GET request
    TEST_ASSERT_EQUAL_INT (
      7, TEST_ASSERT_SUCCESS_ERRNO (zmq_send (client, "GET /\n\n", 7, 0)));

    //  Get HTTP request; ID frame and then request
    TEST_ASSERT_GREATER_THAN_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (server, id, 256, 0)));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (server, buffer, 256, 0));
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer, "GET /\n\n", 7);

    //  Send reply back to client
    char http_response[] = "HTTP/1.0 200 OK\r\n"
                           "Content-Type: text/plain\r\n"
                           "\r\n"
                           "Hello, World!";
    TEST_ASSERT_SUCCESS_ERRNO (zmq_send (server, id, id_size, ZMQ_SNDMORE));
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_send (server, http_response, sizeof (http_response), ZMQ_SNDMORE));

    //  Send zero to close connection to client
    TEST_ASSERT_SUCCESS_ERRNO (zmq_send (server, id, id_size, ZMQ_SNDMORE));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_send (server, NULL, 0, ZMQ_SNDMORE));

    //  Get reply at client and check that it's complete
    TEST_ASSERT_GREATER_THAN_INT (
      0, TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (client, id, 256, 0)));
    TEST_ASSERT_EQUAL_INT (
      sizeof http_response,
      TEST_ASSERT_SUCCESS_ERRNO (zmq_recv (client, buffer, 256, 0)));
    TEST_ASSERT_EQUAL_INT8_ARRAY (buffer, http_response,
                                  sizeof (http_response));

    // //  Get disconnection notification
    // FIXME: why does this block? Bug in STREAM disconnect notification?
    // id_size = zmq_recv (client, id, 256, 0);
    // assert (id_size > 0);
    // rc = zmq_recv (client, buffer, 256, 0);
    // assert (rc == 0);

    test_context_socket_close (server);
    test_context_socket_close (client);
}
void test_stream_disconnect ()
{
    size_t len = MAX_SOCKET_STRING;
    char bind_endpoint[MAX_SOCKET_STRING];
    char connect_endpoint[MAX_SOCKET_STRING];
    void *sockets[2];

    sockets[SERVER] = test_context_socket (ZMQ_STREAM);
    int enabled = 1;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
      sockets[SERVER], ZMQ_STREAM_NOTIFY, &enabled, sizeof (enabled)));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (sockets[SERVER], "tcp://0.0.0.0:*"));
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_getsockopt (sockets[SERVER], ZMQ_LAST_ENDPOINT, bind_endpoint, &len));

    //  Apparently Windows can't connect to 0.0.0.0. A better fix would be welcome.
#ifdef ZMQ_HAVE_WINDOWS
    sprintf (connect_endpoint, "tcp://127.0.0.1:%s",
             strrchr (bind_endpoint, ':') + 1);
#else
    strcpy (connect_endpoint, bind_endpoint);
#endif

    sockets[CLIENT] = test_context_socket (ZMQ_STREAM);
    TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (
      sockets[CLIENT], ZMQ_STREAM_NOTIFY, &enabled, sizeof (enabled)));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (sockets[CLIENT], connect_endpoint));

    // wait for connect notification
    // Server: Grab the 1st frame (peer routing id).
    zmq_msg_t peer_frame;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&peer_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&peer_frame, sockets[SERVER], 0));
    TEST_ASSERT_GREATER_THAN_INT (0, zmq_msg_size (&peer_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&peer_frame));
    TEST_ASSERT_TRUE (has_more (sockets[SERVER]));

    // Server: Grab the 2nd frame (actual payload).
    zmq_msg_t data_frame;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&data_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&data_frame, sockets[SERVER], 0));
    TEST_ASSERT_EQUAL_INT (0, zmq_msg_size (&data_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));

    // Client: Grab the 1st frame (peer routing id).
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&peer_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&peer_frame, sockets[CLIENT], 0));
    TEST_ASSERT_GREATER_THAN_INT (0, zmq_msg_size (&peer_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&peer_frame));
    TEST_ASSERT_TRUE (has_more (sockets[CLIENT]));

    // Client: Grab the 2nd frame (actual payload).
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&data_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_recv (&data_frame, sockets[CLIENT], 0));
    TEST_ASSERT_EQUAL_INT (0, zmq_msg_size (&data_frame));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));

    // Send initial message.
    char blob_data[256];
    size_t blob_size = sizeof (blob_data);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_getsockopt (sockets[CLIENT], ZMQ_ROUTING_ID, blob_data, &blob_size));
    TEST_ASSERT_GREATER_THAN (0, blob_size);
    zmq_msg_t msg;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init_size (&msg, blob_size));
    memcpy (zmq_msg_data (&msg), blob_data, blob_size);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_msg_send (&msg, sockets[dialog[0].turn], ZMQ_SNDMORE));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&msg));
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_msg_init_size (&msg, strlen (dialog[0].text)));
    memcpy (zmq_msg_data (&msg), dialog[0].text, strlen (dialog[0].text));
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_msg_send (&msg, sockets[dialog[0].turn], ZMQ_SNDMORE));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&msg));

    // TODO: make sure this loop doesn't loop forever if something is wrong
    //       with the test (or the implementation).

    int step = 0;
    while (step < steps) {
        // Wait until something happens.
        zmq_pollitem_t items[] = {
          {sockets[SERVER], 0, ZMQ_POLLIN, 0},
          {sockets[CLIENT], 0, ZMQ_POLLIN, 0},
        };
        TEST_ASSERT_SUCCESS_ERRNO (zmq_poll (items, 2, 100));

        // Check for data received by the server.
        if (items[SERVER].revents & ZMQ_POLLIN) {
            TEST_ASSERT_EQUAL_INT (CLIENT, dialog[step].turn);

            // Grab the 1st frame (peer routing id).
            zmq_msg_t peer_frame;
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&peer_frame));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_recv (&peer_frame, sockets[SERVER], 0));
            TEST_ASSERT_GREATER_THAN_INT (0, zmq_msg_size (&peer_frame));
            TEST_ASSERT_TRUE (has_more (sockets[SERVER]));

            // Grab the 2nd frame (actual payload).
            zmq_msg_t data_frame;
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&data_frame));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_recv (&data_frame, sockets[SERVER], 0));

            // Make sure payload matches what we expect.
            const char *const data = (const char *) zmq_msg_data (&data_frame);
            const size_t size = zmq_msg_size (&data_frame);
            // 0-length frame is a disconnection notification.  The server
            // should receive it as the last step in the dialogue.
            if (size == 0) {
                ++step;
                TEST_ASSERT_EQUAL_INT (steps, step);
            } else {
                TEST_ASSERT_EQUAL_INT (strlen (dialog[step].text), size);
                TEST_ASSERT_EQUAL_STRING_LEN (dialog[step].text, data, size);

                ++step;

                TEST_ASSERT_LESS_THAN_INT (steps, step);

                // Prepare the response.
                TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));
                TEST_ASSERT_SUCCESS_ERRNO (
                  zmq_msg_init_size (&data_frame, strlen (dialog[step].text)));
                memcpy (zmq_msg_data (&data_frame), dialog[step].text,
                        zmq_msg_size (&data_frame));

                // Send the response.
                TEST_ASSERT_SUCCESS_ERRNO (
                  zmq_msg_send (&peer_frame, sockets[SERVER], ZMQ_SNDMORE));
                TEST_ASSERT_SUCCESS_ERRNO (
                  zmq_msg_send (&data_frame, sockets[SERVER], ZMQ_SNDMORE));
            }

            // Release resources.
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&peer_frame));
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));
        }

        // Check for data received by the client.
        if (items[CLIENT].revents & ZMQ_POLLIN) {
            TEST_ASSERT_EQUAL_INT (SERVER, dialog[step].turn);

            // Grab the 1st frame (peer routing id).
            zmq_msg_t peer_frame;
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&peer_frame));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_recv (&peer_frame, sockets[CLIENT], 0));
            TEST_ASSERT_GREATER_THAN_INT (0, zmq_msg_size (&peer_frame));
            TEST_ASSERT_TRUE (has_more (sockets[CLIENT]));

            // Grab the 2nd frame (actual payload).
            zmq_msg_t data_frame;
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_init (&data_frame));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_recv (&data_frame, sockets[CLIENT], 0));
            TEST_ASSERT_GREATER_THAN_INT (0, zmq_msg_size (&data_frame));

            // Make sure payload matches what we expect.
            const char *const data = (const char *) zmq_msg_data (&data_frame);
            const size_t size = zmq_msg_size (&data_frame);
            TEST_ASSERT_EQUAL_INT (strlen (dialog[step].text), size);
            TEST_ASSERT_EQUAL_STRING_LEN (dialog[step].text, data, size);

            ++step;

            // Prepare the response (next line in the dialog).
            TEST_ASSERT_LESS_THAN_INT (steps, step);
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_init_size (&data_frame, strlen (dialog[step].text)));
            memcpy (zmq_msg_data (&data_frame), dialog[step].text,
                    zmq_msg_size (&data_frame));

            // Send the response.
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_send (&peer_frame, sockets[CLIENT], ZMQ_SNDMORE));
            TEST_ASSERT_SUCCESS_ERRNO (
              zmq_msg_send (&data_frame, sockets[CLIENT], ZMQ_SNDMORE));

            // Release resources.
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&peer_frame));
            TEST_ASSERT_SUCCESS_ERRNO (zmq_msg_close (&data_frame));
        }
    }
    TEST_ASSERT_EQUAL_INT (steps, step);
    test_context_socket_close (sockets[CLIENT]);
    test_context_socket_close (sockets[SERVER]);
}