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authorFlorian Weimer <fweimer@redhat.com>2017-02-28 15:28:45 +0100
committerFlorian Weimer <fweimer@redhat.com>2017-02-28 15:36:17 +0100
commitcf0bd2f73bd65beab613865bba567d7787836888 (patch)
tree8cde5a2a9547382fac6546c9397aebbb914cb485 /sunrpc/tst-udp-timeout.c
parent37fb019cb02656d0ce0b8d40d56fe8c42f0d1658 (diff)
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.
Diffstat (limited to 'sunrpc/tst-udp-timeout.c')
-rw-r--r--sunrpc/tst-udp-timeout.c402
1 files changed, 402 insertions, 0 deletions
diff --git a/sunrpc/tst-udp-timeout.c b/sunrpc/tst-udp-timeout.c
new file mode 100644
index 0000000000..db9943a03e
--- /dev/null
+++ b/sunrpc/tst-udp-timeout.c
@@ -0,0 +1,402 @@
+/* Test timeout handling in the UDP client.
+ 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 <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, 300 * 1000 });
+ after = get_ticks ();
+ if (test_verbose)
+ printf ("info: test_udp_server: 2.3 second timeout took %f seconds"
+ " (garbage %d)\n",
+ after - before, with_garbage);
+ TEST_VERIFY (2.3 <= 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>