/* Test timeout handling in the UDP client.

   Copyright (C) 2017-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <netinet/in.h>

#include <rpc/clnt.h>

#include <rpc/svc.h>

#include <stdbool.h>

#include <string.h>

#include <support/check.h>

#include <support/namespace.h>

#include <support/test-driver.h>

#include <support/xsocket.h>

#include <support/xunistd.h>

#include <sys/socket.h>

#include <time.h>

#include <unistd.h>

/* Test data serialization and deserialization.   */

struct test_query

{

  uint32_t a;

  uint32_t b;

  uint32_t timeout_ms;

  uint32_t wait_for_seq;

  uint32_t garbage_packets;

};

static bool_t

xdr_test_query (XDR *xdrs, void *data, ...)

{

  struct test_query *p = data;

  return xdr_uint32_t (xdrs, &p->a)

    && xdr_uint32_t (xdrs, &p->b)

    && xdr_uint32_t (xdrs, &p->timeout_ms)

    && xdr_uint32_t (xdrs, &p->wait_for_seq)

    && xdr_uint32_t (xdrs, &p->garbage_packets);

}

struct test_response

{

  uint32_t seq;

  uint32_t sum;

};

static bool_t

xdr_test_response (XDR *xdrs, void *data, ...)

{

  struct test_response *p = data;

  return xdr_uint32_t (xdrs, &p->seq)

    && xdr_uint32_t (xdrs, &p->sum);

}

/* Implementation of the test server.  */

enum

  {

    /* RPC parameters, chosen at random.  */

    PROGNUM = 15717,

    VERSNUM = 13689,

    /* Main RPC operation.  */

    PROC_ADD = 1,

    /* Reset the sequence number.  */

    PROC_RESET_SEQ,

    /* Request process termination.  */

    PROC_EXIT,

    /* Special exit status to mark successful processing.  */

    EXIT_MARKER = 55,

  };

static void

server_dispatch (struct svc_req *request, SVCXPRT *transport)

{

  /* Query sequence number.  */

  static uint32_t seq = 0;

  ++seq;

  if (test_verbose)

    printf ("info: server_dispatch seq=%u rq_proc=%lu\n",

            seq, request->rq_proc);

  switch (request->rq_proc)

    {

    case PROC_ADD:

      {

        struct test_query query;

        memset (&query, 0xc0, sizeof (query));

        TEST_VERIFY_EXIT

          (svc_getargs (transport, xdr_test_query,

                        (void *) &query));

        if (test_verbose)

          printf ("  a=%u b=%u timeout_ms=%u wait_for_seq=%u"

                  " garbage_packets=%u\n",

                  query.a, query.b, query.timeout_ms, query.wait_for_seq,

                  query.garbage_packets);

        if (seq < query.wait_for_seq)

          {

            /* No response at this point.  */

            if (test_verbose)

              printf ("  skipped response\n");

            break;

          }

        if (query.garbage_packets > 0)

          {

            int per_packet_timeout;

            if (query.timeout_ms > 0)

              per_packet_timeout

                = query.timeout_ms * 1000 / query.garbage_packets;

            else

              per_packet_timeout = 0;

            char buf[20];

            memset (&buf, 0xc0, sizeof (buf));

            for (int i = 0; i < query.garbage_packets; ++i)

              {

                /* 13 is relatively prime to 20 = sizeof (buf) + 1, so

                   the len variable will cover the entire interval

                   [0, 20] if query.garbage_packets is sufficiently

                   large.  */

                size_t len = (i * 13 + 1) % (sizeof (buf) + 1);

                TEST_VERIFY (sendto (transport->xp_sock,

                                     buf, len, MSG_NOSIGNAL,

                                     (struct sockaddr *) &transport->xp_raddr,

                                     transport->xp_addrlen) == len);

                if (per_packet_timeout > 0)

                  usleep (per_packet_timeout);

              }

          }

        else if (query.timeout_ms > 0)

          usleep (query.timeout_ms * 1000);

        struct test_response response =

          {

            .seq = seq,

            .sum = query.a + query.b,

          };

        TEST_VERIFY (svc_sendreply (transport, xdr_test_response,

                                    (void *) &response));

      }

      break;

    case PROC_RESET_SEQ:

      seq = 0;

      TEST_VERIFY (svc_sendreply (transport, (xdrproc_t) xdr_void, NULL));

      break;

    case PROC_EXIT:

      TEST_VERIFY (svc_sendreply (transport, (xdrproc_t) xdr_void, NULL));

      _exit (EXIT_MARKER);

      break;

    default:

      FAIL_EXIT1 ("invalid rq_proc value: %lu", request->rq_proc);

      break;

    }

}

/* Implementation of the test client.  */

static struct test_response

test_call (CLIENT *clnt, int proc, struct test_query query,

           struct timeval timeout)

{

  if (test_verbose)

    printf ("info: test_call proc=%d timeout=%lu.%06lu\n",

            proc, (unsigned long) timeout.tv_sec,

            (unsigned long) timeout.tv_usec);

  struct test_response response;

  TEST_VERIFY_EXIT (clnt_call (clnt, proc,

                               xdr_test_query, (void *) &query,

                               xdr_test_response, (void *) &response,

                               timeout)

                    == RPC_SUCCESS);

  return response;

}

static void

test_call_timeout (CLIENT *clnt, int proc, struct test_query query,

                   struct timeval timeout)

{

  struct test_response response;

  TEST_VERIFY (clnt_call (clnt, proc,

                          xdr_test_query, (void *) &query,

                          xdr_test_response, (void *) &response,

                          timeout)

               == RPC_TIMEDOUT);

}

/* Complete one regular RPC call to drain the server socket

   buffer.  Resets the sequence number.  */

static void

test_call_flush (CLIENT *clnt)

{

  /* This needs a longer timeout to flush out all pending requests.

     The choice of 5 seconds is larger than the per-response timeouts

     requested via the timeout_ms field.  */

  if (test_verbose)

    printf ("info: flushing pending queries\n");

  TEST_VERIFY_EXIT (clnt_call (clnt, PROC_RESET_SEQ,

                               (xdrproc_t) xdr_void, NULL,

                               (xdrproc_t) xdr_void, NULL,

                               ((struct timeval) { 5, 0 }))

                    == RPC_SUCCESS);

}

/* Return the number seconds since an arbitrary point in time.  */

static double

get_ticks (void)

{

  {

    struct timespec ts;

    if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0)

      return ts.tv_sec + ts.tv_nsec * 1e-9;

  }

  {

    struct timeval tv;

    TEST_VERIFY_EXIT (gettimeofday (&tv, NULL) == 0);

    return tv.tv_sec + tv.tv_usec * 1e-6;

  }

}

static void

test_udp_server (int port)

{

  struct sockaddr_in sin =

    {

      .sin_family = AF_INET,

      .sin_addr.s_addr = htonl (INADDR_LOOPBACK),

      .sin_port = htons (port)

    };

  int sock = RPC_ANYSOCK;

  /* The client uses a 1.5 second timeout for retries.  The timeouts

     are arbitrary, but chosen so that there is a substantial gap

     between them, but the total time spent waiting is not too

     large.  */

  CLIENT *clnt = clntudp_create (&sin, PROGNUM, VERSNUM,

                                 (struct timeval) { 1, 500 * 1000 },

                                 &sock);

  TEST_VERIFY_EXIT (clnt != NULL);

  /* Basic call/response test.  */

  struct test_response response = test_call

    (clnt, PROC_ADD,

     (struct test_query) { .a = 17, .b = 4 },

     (struct timeval) { 3, 0 });

  TEST_VERIFY (response.sum == 21);

  TEST_VERIFY (response.seq == 1);

  /* Check that garbage packets do not interfere with timeout

     processing.  */

  double before = get_ticks ();

  response = test_call

    (clnt, PROC_ADD,

     (struct test_query) {

       .a = 19, .b = 4, .timeout_ms = 500, .garbage_packets = 21,

     },

     (struct timeval) { 3, 0 });

  TEST_VERIFY (response.sum == 23);

  TEST_VERIFY (response.seq == 2);

  double after = get_ticks ();

  if (test_verbose)

    printf ("info: 21 garbage packets took %f seconds\n", after - before);

  /* Expected timeout is 0.5 seconds.  Add some slack in case process

     scheduling delays processing the query or response, but do not

     accept a retry (which would happen at 1.5 seconds).  */

  TEST_VERIFY (0.5 <= after - before);

  TEST_VERIFY (after - before < 1.2);

  test_call_flush (clnt);

  /* Check that missing a response introduces a 1.5 second timeout, as

     requested when calling clntudp_create.  */

  before = get_ticks ();

  response = test_call

    (clnt, PROC_ADD,

     (struct test_query) { .a = 170, .b = 40, .wait_for_seq = 2 },

     (struct timeval) { 3, 0 });

  TEST_VERIFY (response.sum == 210);

  TEST_VERIFY (response.seq == 2);

  after = get_ticks ();

  if (test_verbose)

    printf ("info: skipping one response took %f seconds\n",

            after - before);

  /* Expected timeout is 1.5 seconds.  Do not accept a second retry

     (which would happen at 3 seconds).  */

  TEST_VERIFY (1.5 <= after - before);

  TEST_VERIFY (after - before < 2.9);

  test_call_flush (clnt);

  /* Check that the overall timeout wins against the per-query

     timeout.  */

  before = get_ticks ();

  test_call_timeout

    (clnt, PROC_ADD,

     (struct test_query) { .a = 170, .b = 41, .wait_for_seq = 2 },

     (struct timeval) { 0, 750 * 1000 });

  after = get_ticks ();

  if (test_verbose)

    printf ("info: 0.75 second timeout took %f seconds\n",

            after - before);

  TEST_VERIFY (0.75 <= after - before);

  TEST_VERIFY (after - before < 1.4);

  test_call_flush (clnt);

  for (int with_garbage = 0; with_garbage < 2; ++with_garbage)

    {

      /* Check that no response at all causes the client to bail out.  */

      before = get_ticks ();

      test_call_timeout

        (clnt, PROC_ADD,

         (struct test_query) {

           .a = 170, .b = 40, .timeout_ms = 1200,

           .garbage_packets = with_garbage * 21

         },

         (struct timeval) { 0, 750 * 1000 });

      after = get_ticks ();

      if (test_verbose)

        printf ("info: test_udp_server: 0.75 second timeout took %f seconds"

                " (garbage %d)\n",

                after - before, with_garbage);

      TEST_VERIFY (0.75 <= after - before);

      TEST_VERIFY (after - before < 1.4);

      test_call_flush (clnt);

      /* As above, but check the total timeout.  */

      before = get_ticks ();

      test_call_timeout

        (clnt, PROC_ADD,

         (struct test_query) {

           .a = 170, .b = 40, .timeout_ms = 3000,

           .garbage_packets = with_garbage * 30

         },

         (struct timeval) { 2, 500 * 1000 });

      after = get_ticks ();

      if (test_verbose)

        printf ("info: test_udp_server: 2.5 second timeout took %f seconds"

                " (garbage %d)\n",

                after - before, with_garbage);

      TEST_VERIFY (2.5 <= after - before);

      TEST_VERIFY (after - before < 3.0);

      test_call_flush (clnt);

    }

  TEST_VERIFY_EXIT (clnt_call (clnt, PROC_EXIT,

                               (xdrproc_t) xdr_void, NULL,

                               (xdrproc_t) xdr_void, NULL,

                               ((struct timeval) { 5, 0 }))

                    == RPC_SUCCESS);

  clnt_destroy (clnt);

}

static int

do_test (void)

{

  support_become_root ();

  support_enter_network_namespace ();

  SVCXPRT *transport = svcudp_create (RPC_ANYSOCK);

  TEST_VERIFY_EXIT (transport != NULL);

  TEST_VERIFY (svc_register (transport, PROGNUM, VERSNUM, server_dispatch, 0));

  pid_t pid = xfork ();

  if (pid == 0)

    {

      svc_run ();

      FAIL_EXIT1 ("supposed to be unreachable");

    }

  test_udp_server (transport->xp_port);

  int status;

  xwaitpid (pid, &status, 0);

  TEST_VERIFY (WIFEXITED (status) && WEXITSTATUS (status) == EXIT_MARKER);

  SVC_DESTROY (transport);

  return 0;

}

/* The minimum run time is around 17 seconds.  */

#define TIMEOUT 25

#include <support/test-driver.c>