sunrpc: Improvements for UDP client timeout handling [BZ #20257]

This commit fixes various aspects in the UDP client timeout handling.
Timeouts are now applied in a more consistent fashion.  Discarded UDP
packets no longer prevent the timeout from happening at all.

1 files changed, 188 insertions, 0 deletions

diff --git a/inet/tst-deadline.c b/inet/tst-deadline.c
new file mode 100644
index 0000000000..ed04345c35
--- /dev/null
+++ b/inet/tst-deadline.c
@@ -0,0 +1,188 @@
+/* Tests for computing deadlines for timeouts.
+   Copyright (C) 2017 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 <inet/net-internal.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <support/check.h>
+
+/* Find the maximum value which can be represented in a time_t.  */
+static time_t
+time_t_max (void)
+{
+  _Static_assert (0 > (time_t) -1, "time_t is signed");
+  uintmax_t current = 1;
+  while (true)
+    {
+      uintmax_t next = current * 2;
+      /* This cannot happen because time_t is signed.  */
+      TEST_VERIFY_EXIT (next > current);
+      ++next;
+      if ((time_t) next < 0 || next != (uintmax_t) (time_t) next)
+        /* Value cannot be represented in time_t.  Return the previous
+           value. */
+        return current;
+      current = next;
+    }
+}
+
+static int
+do_test (void)
+{
+  {
+    struct deadline_current_time current_time = __deadline_current_time ();
+    TEST_VERIFY (current_time.current.tv_sec >= 0);
+    current_time = __deadline_current_time ();
+    /* Due to CLOCK_MONOTONIC, either seconds or nanoseconds are
+       greater than zero.  This is also true for the gettimeofday
+       fallback.  */
+    TEST_VERIFY (current_time.current.tv_sec >= 0);
+    TEST_VERIFY (current_time.current.tv_sec > 0
+                 || current_time.current.tv_nsec > 0);
+  }
+
+  /* Check basic computations of deadlines.  */
+  struct deadline_current_time current_time = { { 1, 123456789 } };
+  struct deadline deadline = __deadline_from_timeval
+    (current_time, (struct timeval) { 0, 1 });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 123457789);
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1);
+
+  deadline = __deadline_from_timeval
+    (current_time, ((struct timeval) { 0, 2 }));
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 123458789);
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1);
+
+  deadline = __deadline_from_timeval
+    (current_time, ((struct timeval) { 1, 0 }));
+  TEST_VERIFY (deadline.absolute.tv_sec == 2);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 123456789);
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1000);
+
+  /* Check if timeouts are correctly rounded up to the next
+     millisecond.  */
+  for (int i = 0; i < 999999; ++i)
+    {
+      ++current_time.current.tv_nsec;
+      TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1000);
+    }
+
+  /* A full millisecond has elapsed, so the time to the deadline is
+     now less than 1000.  */
+  ++current_time.current.tv_nsec;
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 999);
+
+  /* Check __deadline_to_ms carry-over.  */
+  current_time = (struct deadline_current_time) { { 9, 123456789 } };
+  deadline = (struct deadline) { { 10, 122456789 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 999);
+  deadline = (struct deadline) { { 10, 122456790 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1000);
+  deadline = (struct deadline) { { 10, 123456788 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1000);
+  deadline = (struct deadline) { { 10, 123456789 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 1000);
+
+  /* Check __deadline_to_ms overflow.  */
+  deadline = (struct deadline) { { INT_MAX - 1, 1 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == INT_MAX);
+
+  /* Check __deadline_to_ms for elapsed deadlines.  */
+  current_time = (struct deadline_current_time) { { 9, 123456789 } };
+  deadline.absolute = current_time.current;
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 0);
+  current_time = (struct deadline_current_time) { { 9, 123456790 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 0);
+  current_time = (struct deadline_current_time) { { 10, 0 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 0);
+  current_time = (struct deadline_current_time) { { 10, 123456788 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 0);
+  current_time = (struct deadline_current_time) { { 10, 123456789 } };
+  TEST_VERIFY (__deadline_to_ms (current_time, deadline) == 0);
+
+  /* Check carry-over in __deadline_from_timeval.  */
+  current_time = (struct deadline_current_time) { { 9, 998000001 } };
+  for (int i = 0; i < 2000; ++i)
+    {
+      deadline = __deadline_from_timeval
+        (current_time, (struct timeval) { 1, i });
+      TEST_VERIFY (deadline.absolute.tv_sec == 10);
+      TEST_VERIFY (deadline.absolute.tv_nsec == 998000001 + i * 1000);
+    }
+  for (int i = 2000; i < 3000; ++i)
+    {
+      deadline = __deadline_from_timeval
+        (current_time, (struct timeval) { 2, i });
+      TEST_VERIFY (deadline.absolute.tv_sec == 12);
+      TEST_VERIFY (deadline.absolute.tv_nsec == 1 + (i - 2000) * 1000);
+    }
+
+  /* Check infinite deadlines.  */
+  deadline = __deadline_from_timeval
+    ((struct deadline_current_time) { { 0, 1000 * 1000 * 1000 - 1000 } },
+     (struct timeval) { time_t_max (), 1 });
+  TEST_VERIFY (__deadline_is_infinite (deadline));
+  deadline = __deadline_from_timeval
+    ((struct deadline_current_time) { { 0, 1000 * 1000 * 1000 - 1001 } },
+     (struct timeval) { time_t_max (), 1 });
+  TEST_VERIFY (!__deadline_is_infinite (deadline));
+  deadline = __deadline_from_timeval
+    ((struct deadline_current_time)
+       { { time_t_max (), 1000 * 1000 * 1000 - 1000 } },
+     (struct timeval) { 0, 1 });
+  TEST_VERIFY (__deadline_is_infinite (deadline));
+  deadline = __deadline_from_timeval
+    ((struct deadline_current_time)
+       { { time_t_max () / 2 + 1, 0 } },
+     (struct timeval) { time_t_max () / 2 + 1, 0 });
+  TEST_VERIFY (__deadline_is_infinite (deadline));
+
+  /* Check __deadline_first behavior.  */
+  deadline = __deadline_first
+    ((struct deadline) { { 1, 2 } },
+     (struct deadline) { { 1, 3 } });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 2);
+  deadline = __deadline_first
+    ((struct deadline) { { 1, 3 } },
+     (struct deadline) { { 1, 2 } });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 2);
+  deadline = __deadline_first
+    ((struct deadline) { { 1, 2 } },
+     (struct deadline) { { 2, 1 } });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 2);
+  deadline = __deadline_first
+    ((struct deadline) { { 1, 2 } },
+     (struct deadline) { { 2, 4 } });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 2);
+  deadline = __deadline_first
+    ((struct deadline) { { 2, 4 } },
+     (struct deadline) { { 1, 2 } });
+  TEST_VERIFY (deadline.absolute.tv_sec == 1);
+  TEST_VERIFY (deadline.absolute.tv_nsec == 2);
+
+  return 0;
+}
+
+#include <support/test-driver.c>