1 /* Test that garbage packets do not affect timeout handling.
2    Copyright (C) 2017-2022 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; if not, see
17    <https://www.gnu.org/licenses/>.  */
18 
19 #include <netinet/in.h>
20 #include <rpc/clnt.h>
21 #include <rpc/svc.h>
22 #include <stdbool.h>
23 #include <support/check.h>
24 #include <support/namespace.h>
25 #include <support/xsocket.h>
26 #include <support/xthread.h>
27 #include <sys/socket.h>
28 #include <unistd.h>
29 
30 /* Descriptor for the server UDP socket.  */
31 static int server_fd;
32 
33 static void *
garbage_sender_thread(void * unused)34 garbage_sender_thread (void *unused)
35 {
36   while (true)
37     {
38       struct sockaddr_storage sa;
39       socklen_t salen = sizeof (sa);
40       char buf[1];
41       if (recvfrom (server_fd, buf, sizeof (buf), 0,
42                     (struct sockaddr *) &sa, &salen) < 0)
43         FAIL_EXIT1 ("recvfrom: %m");
44 
45       /* Send garbage packets indefinitely.  */
46       buf[0] = 0;
47       while (true)
48         {
49           /* sendto can fail if the client closed the socket.  */
50           if (sendto (server_fd, buf, sizeof (buf), 0,
51                       (struct sockaddr *) &sa, salen) < 0)
52             break;
53 
54           /* Wait a bit, to avoid burning too many CPU cycles in a
55              tight loop.  The wait period must be much shorter than
56              the client timeouts configured below.  */
57           usleep (50 * 1000);
58         }
59     }
60 }
61 
62 static int
do_test(void)63 do_test (void)
64 {
65   support_become_root ();
66   support_enter_network_namespace ();
67 
68   server_fd = xsocket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
69   struct sockaddr_in server_address =
70     {
71       .sin_family = AF_INET,
72       .sin_addr.s_addr = htonl (INADDR_LOOPBACK),
73     };
74   xbind (server_fd,
75          (struct sockaddr *) &server_address, sizeof (server_address));
76   {
77     socklen_t sinlen = sizeof (server_address);
78     xgetsockname (server_fd, (struct sockaddr *) &server_address, &sinlen);
79     TEST_VERIFY (sizeof (server_address) == sinlen);
80   }
81 
82   /* Garbage packet source.  */
83   xpthread_detach (xpthread_create (NULL, garbage_sender_thread, NULL));
84 
85   /* Test client.  Use an arbitrary timeout of one second, which is
86      much longer than the garbage packet interval, but still
87      reasonably short, so that the test completes quickly.  */
88   int client_fd = RPC_ANYSOCK;
89   CLIENT *clnt = clntudp_create (&server_address,
90                                  1, 2, /* Arbitrary RPC endpoint numbers.  */
91                                  (struct timeval) { 1, 0 },
92                                  &client_fd);
93   if (clnt == NULL)
94     FAIL_EXIT1 ("clntudp_create: %m");
95 
96   TEST_VERIFY (clnt_call (clnt, 3, /* Arbitrary RPC procedure number.  */
97                           (xdrproc_t) xdr_void, NULL,
98                           (xdrproc_t) xdr_void, NULL,
99                           ((struct timeval) { 1, 0 })));
100 
101   return 0;
102 }
103 
104 #include <support/test-driver.c>
105