1 /* DNS test framework and libresolv redirection.
2 Copyright (C) 2016-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
19 #include <support/resolv_test.h>
21 #include <arpa/inet.h>
29 #include <support/check.h>
30 #include <support/namespace.h>
31 #include <support/support.h>
32 #include <support/test-driver.h>
33 #include <support/xsocket.h>
34 #include <support/xthread.h>
35 #include <support/xunistd.h>
39 /* Response builder. */
43 max_response_length = 65536
46 /* Used for locating domain names containing for the purpose of
47 forming compression references. */
48 struct compressed_name
52 unsigned char name[]; /* Without terminating NUL. */
55 static struct compressed_name *
56 allocate_compressed_name (const unsigned char *encoded, unsigned int offset)
58 /* Compute the length of the domain name. */
61 const unsigned char *p;
62 for (p = encoded; *p != '\0';)
64 /* No compression references are allowed. */
65 TEST_VERIFY (*p <= 63);
66 /* Skip over the label. */
70 ++length; /* For the terminating NUL byte. */
72 TEST_VERIFY_EXIT (length <= 255);
74 struct compressed_name *result
75 = xmalloc (offsetof (struct compressed_name, name) + length);
76 result->offset = offset;
77 result->length = length;
78 memcpy (result->name, encoded, length);
82 /* Convert CH to lower case. Only change letters in the ASCII
84 static inline unsigned char
85 ascii_tolower (unsigned char ch)
87 if ('A' <= ch && ch <= 'Z')
88 return ch - 'A' + 'a';
93 /* Compare both names, for use with tsearch. The order is arbitrary,
94 but the comparison is case-insenstive. */
96 compare_compressed_name (const void *left, const void *right)
98 const struct compressed_name *crleft = left;
99 const struct compressed_name *crright = right;
101 if (crleft->length != crright->length)
102 /* The operands are converted to int before the subtraction. */
103 return crleft->length - crright->length;
105 const unsigned char *nameleft = crleft->name;
106 const unsigned char *nameright = crright->name;
110 int lenleft = *nameleft++;
111 int lenright = *nameright++;
113 /* Labels must not e compression references. */
114 TEST_VERIFY (lenleft <= 63);
115 TEST_VERIFY (lenright <= 63);
117 if (lenleft != lenright)
120 /* End of name reached without spotting a difference. */
122 /* Compare the label in a case-insenstive manner. */
123 const unsigned char *endnameleft = nameleft + lenleft;
124 while (nameleft < endnameleft)
127 int r = *nameright++;
130 l = ascii_tolower (l);
131 r = ascii_tolower (r);
139 struct resolv_response_builder
141 const unsigned char *query_buffer;
144 size_t offset; /* Bytes written so far in buffer. */
145 ns_sect section; /* Current section in the DNS packet. */
146 unsigned int truncate_bytes; /* Bytes to remove at end of response. */
147 bool drop; /* Discard generated response. */
148 bool close; /* Close TCP client connection. */
150 /* Offset of the two-byte RDATA length field in the currently
151 written RDATA sub-structure. 0 if no RDATA is being written. */
152 size_t current_rdata_offset;
154 /* tsearch tree for locating targets for label compression. */
155 void *compression_offsets;
157 /* Must be last. Not zeroed for performance reasons. */
158 unsigned char buffer[max_response_length];
161 /* Response builder. */
164 resolv_response_init (struct resolv_response_builder *b,
165 struct resolv_response_flags flags)
168 FAIL_EXIT1 ("response_init: called at offset %zu", b->offset);
169 if (b->query_length < 12)
170 FAIL_EXIT1 ("response_init called for a query of size %zu",
172 if (flags.rcode > 15)
173 FAIL_EXIT1 ("response_init: invalid RCODE %u", flags.rcode);
175 /* Copy the transaction ID. */
176 b->buffer[0] = b->query_buffer[0];
177 b->buffer[1] = b->query_buffer[1];
179 /* Initialize the flags. */
180 b->buffer[2] = 0x80; /* Mark as response. */
181 b->buffer[2] |= b->query_buffer[2] & 0x01; /* Copy the RD bit. */
183 b->buffer[2] |= 0x02;
184 b->buffer[3] = flags.rcode;
186 b->buffer[3] |= 0x80;
188 b->buffer[3] |= 0x20;
190 /* Fill in the initial section count values. */
191 b->buffer[4] = flags.qdcount >> 8;
192 b->buffer[5] = flags.qdcount;
193 b->buffer[6] = flags.ancount >> 8;
194 b->buffer[7] = flags.ancount;
195 b->buffer[8] = flags.nscount >> 8;
196 b->buffer[9] = flags.nscount;
197 b->buffer[10] = flags.adcount >> 8;
198 b->buffer[11] = flags.adcount;
204 resolv_response_section (struct resolv_response_builder *b, ns_sect section)
207 FAIL_EXIT1 ("resolv_response_section: response_init not called before");
208 if (section < b->section)
209 FAIL_EXIT1 ("resolv_response_section: cannot go back to previous section");
210 b->section = section;
213 /* Add a single byte to B. */
215 response_add_byte (struct resolv_response_builder *b, unsigned char ch)
217 if (b->offset == max_response_length)
218 FAIL_EXIT1 ("DNS response exceeds 64 KiB limit");
219 b->buffer[b->offset] = ch;
223 /* Add a 16-bit word VAL to B, in big-endian format. */
225 response_add_16 (struct resolv_response_builder *b, uint16_t val)
227 response_add_byte (b, val >> 8);
228 response_add_byte (b, val);
231 /* Increment the pers-section record counter in the packet header. */
233 response_count_increment (struct resolv_response_builder *b)
235 unsigned int offset = b->section;
236 offset = 4 + 2 * offset;
237 ++b->buffer[offset + 1];
238 if (b->buffer[offset + 1] == 0)
242 if (b->buffer[offset] == 0)
244 FAIL_EXIT1 ("too many records in section");
249 resolv_response_add_question (struct resolv_response_builder *b,
250 const char *name, uint16_t class, uint16_t type)
253 FAIL_EXIT1 ("resolv_response_add_question: "
254 "resolv_response_init not called");
255 if (b->section != ns_s_qd)
256 FAIL_EXIT1 ("resolv_response_add_question: "
257 "must be called in the question section");
259 resolv_response_add_name (b, name);
260 response_add_16 (b, type);
261 response_add_16 (b, class);
263 response_count_increment (b);
267 resolv_response_add_name (struct resolv_response_builder *b,
268 const char *const origname)
270 unsigned char encoded_name[NS_MAXDNAME];
271 if (ns_name_pton (origname, encoded_name, sizeof (encoded_name)) < 0)
272 FAIL_EXIT1 ("ns_name_pton (\"%s\"): %m", origname);
274 /* Copy the encoded name into the output buffer, apply compression
276 for (const unsigned char *name = encoded_name; ;)
280 /* We have reached the end of the name. Add the terminating
282 response_add_byte (b, '\0');
286 /* Set to the compression target if compression is possible. */
287 struct compressed_name *crname_target;
289 /* Compression references can only reach the beginning of the
291 enum { compression_limit = 1 << 12 };
294 /* The trailing part of the name to be looked up in the tree
295 with the compression targets. */
296 struct compressed_name *crname
297 = allocate_compressed_name (name, b->offset);
299 if (b->offset < compression_limit)
301 /* Add the name to the tree, for future compression
303 void **ptr = tsearch (crname, &b->compression_offsets,
304 compare_compressed_name);
306 FAIL_EXIT1 ("tsearch out of memory");
307 crname_target = *ptr;
309 if (crname_target != crname)
310 /* The new name was not actually added to the tree.
314 /* Signal that the tree did not yet contain the name,
315 but keep the allocation because it is now part of the
317 crname_target = NULL;
321 /* This name cannot be reached by a compression reference.
322 No need to add it to the tree for future reference. */
323 void **ptr = tfind (crname, &b->compression_offsets,
324 compare_compressed_name);
326 crname_target = *ptr;
328 crname_target = NULL;
329 TEST_VERIFY (crname_target != crname);
330 /* Not added to the tree. */
335 if (crname_target != NULL)
337 /* The name is known. Reference the previous location. */
338 unsigned int old_offset = crname_target->offset;
339 TEST_VERIFY_EXIT (old_offset < compression_limit);
340 response_add_byte (b, 0xC0 | (old_offset >> 8));
341 response_add_byte (b, old_offset);
346 /* The name is new. Add this label. */
347 unsigned int len = 1 + *name;
348 resolv_response_add_data (b, name, len);
355 resolv_response_open_record (struct resolv_response_builder *b,
357 uint16_t class, uint16_t type, uint32_t ttl)
359 if (b->section == ns_s_qd)
360 FAIL_EXIT1 ("resolv_response_open_record called in question section");
361 if (b->current_rdata_offset != 0)
362 FAIL_EXIT1 ("resolv_response_open_record called with open record");
364 resolv_response_add_name (b, name);
365 response_add_16 (b, type);
366 response_add_16 (b, class);
367 response_add_16 (b, ttl >> 16);
368 response_add_16 (b, ttl);
370 b->current_rdata_offset = b->offset;
371 /* Add room for the RDATA length. */
372 response_add_16 (b, 0);
377 resolv_response_close_record (struct resolv_response_builder *b)
379 size_t rdata_offset = b->current_rdata_offset;
380 if (rdata_offset == 0)
381 FAIL_EXIT1 ("response_close_record called without open record");
382 size_t rdata_length = b->offset - rdata_offset - 2;
383 if (rdata_length > 65535)
384 FAIL_EXIT1 ("RDATA length %zu exceeds limit", rdata_length);
385 b->buffer[rdata_offset] = rdata_length >> 8;
386 b->buffer[rdata_offset + 1] = rdata_length;
387 response_count_increment (b);
388 b->current_rdata_offset = 0;
392 resolv_response_add_data (struct resolv_response_builder *b,
393 const void *data, size_t length)
395 size_t remaining = max_response_length - b->offset;
396 if (remaining < length)
397 FAIL_EXIT1 ("resolv_response_add_data: not enough room for %zu bytes",
399 memcpy (b->buffer + b->offset, data, length);
404 resolv_response_drop (struct resolv_response_builder *b)
410 resolv_response_close (struct resolv_response_builder *b)
416 resolv_response_truncate_data (struct resolv_response_builder *b, size_t count)
419 FAIL_EXIT1 ("resolv_response_truncate_data: argument too large: %zu",
421 b->truncate_bytes = count;
426 resolv_response_length (const struct resolv_response_builder *b)
432 resolv_response_buffer (const struct resolv_response_builder *b)
434 unsigned char *result = xmalloc (b->offset);
435 memcpy (result, b->buffer, b->offset);
439 struct resolv_response_builder *
440 resolv_response_builder_allocate (const unsigned char *query_buffer,
443 struct resolv_response_builder *b = xmalloc (sizeof (*b));
444 memset (b, 0, offsetof (struct resolv_response_builder, buffer));
445 b->query_buffer = query_buffer;
446 b->query_length = query_length;
451 resolv_response_builder_free (struct resolv_response_builder *b)
453 tdestroy (b->compression_offsets, free);
457 /* DNS query processing. */
459 /* Data extracted from the question section of a DNS packet. */
462 char qname[MAXDNAME];
465 struct resolv_edns_info edns;
468 /* Update *INFO from the specified DNS packet. */
470 parse_query (struct query_info *info,
471 const unsigned char *buffer, size_t length)
474 _Static_assert (sizeof (hd) == 12, "DNS header size");
475 if (length < sizeof (hd))
476 FAIL_EXIT1 ("malformed DNS query: too short: %zu bytes", length);
477 memcpy (&hd, buffer, sizeof (hd));
479 if (ntohs (hd.qdcount) != 1)
480 FAIL_EXIT1 ("malformed DNS query: wrong question count: %d",
481 (int) ntohs (hd.qdcount));
482 if (ntohs (hd.ancount) != 0)
483 FAIL_EXIT1 ("malformed DNS query: wrong answer count: %d",
484 (int) ntohs (hd.ancount));
485 if (ntohs (hd.nscount) != 0)
486 FAIL_EXIT1 ("malformed DNS query: wrong authority count: %d",
487 (int) ntohs (hd.nscount));
488 if (ntohs (hd.arcount) > 1)
489 FAIL_EXIT1 ("malformed DNS query: wrong additional count: %d",
490 (int) ntohs (hd.arcount));
492 int ret = dn_expand (buffer, buffer + length, buffer + sizeof (hd),
493 info->qname, sizeof (info->qname));
495 FAIL_EXIT1 ("malformed DNS query: cannot uncompress QNAME");
497 /* Obtain QTYPE and QCLASS. */
498 size_t remaining = length - (12 + ret);
504 if (remaining < sizeof (qtype_qclass))
505 FAIL_EXIT1 ("malformed DNS query: "
506 "query lacks QCLASS/QTYPE, QNAME: %s", info->qname);
507 memcpy (&qtype_qclass, buffer + 12 + ret, sizeof (qtype_qclass));
508 info->qclass = ntohs (qtype_qclass.qclass);
509 info->qtype = ntohs (qtype_qclass.qtype);
511 memset (&info->edns, 0, sizeof (info->edns));
512 if (ntohs (hd.arcount) > 0)
514 /* Parse EDNS record. */
515 struct __attribute__ ((packed, aligned (1)))
520 uint8_t edns_extended_rcode;
521 uint8_t edns_version;
525 _Static_assert (sizeof (rr) == 11, "EDNS record size");
527 if (remaining < 4 + sizeof (rr))
528 FAIL_EXIT1 ("mailformed DNS query: no room for EDNS record");
529 memcpy (&rr, buffer + 12 + ret + 4, sizeof (rr));
531 FAIL_EXIT1 ("malformed DNS query: invalid OPT RNAME: %d\n", rr.root);
532 if (rr.rtype != htons (41))
533 FAIL_EXIT1 ("malformed DNS query: invalid OPT type: %d\n",
535 info->edns.active = true;
536 info->edns.extended_rcode = rr.edns_extended_rcode;
537 info->edns.version = rr.edns_version;
538 info->edns.flags = ntohs (rr.flags);
539 info->edns.payload_size = ntohs (rr.payload);
544 /* Main testing framework. */
546 /* Per-server information. One struct is allocated for each test
548 struct resolv_test_server
550 /* Local address of the server. UDP and TCP use the same port. */
551 struct sockaddr_in address;
553 /* File descriptor of the UDP server, or -1 if this server is
557 /* File descriptor of the TCP server, or -1 if this server is
561 /* Counter of the number of responses processed so far. */
562 size_t response_number;
564 /* Thread handles for the server threads (if not disabled in the
566 pthread_t thread_udp;
567 pthread_t thread_tcp;
570 /* Main struct for keeping track of libresolv redirection and
574 /* After initialization, any access to the struct must be performed
575 while this lock is acquired. */
576 pthread_mutex_t lock;
578 /* Data for each test server. */
579 struct resolv_test_server servers[resolv_max_test_servers];
581 /* Used if config.single_thread_udp is true. */
582 pthread_t thread_udp_single;
584 struct resolv_redirect_config config;
585 bool termination_requested;
588 /* Function implementing a server thread. */
589 typedef void (*thread_callback) (struct resolv_test *, int server_index);
591 /* Storage for thread-specific data, for passing to the
592 thread_callback function. */
593 struct thread_closure
595 struct resolv_test *obj; /* Current test object. */
596 thread_callback callback; /* Function to call. */
597 int server_index; /* Index of the implemented server. */
600 /* Wrap response_callback as a function which can be passed to
603 thread_callback_wrapper (void *arg)
605 struct thread_closure *closure = arg;
606 closure->callback (closure->obj, closure->server_index);
611 /* Start a server thread for the specified SERVER_INDEX, implemented
614 start_server_thread (struct resolv_test *obj, int server_index,
615 thread_callback callback)
617 struct thread_closure *closure = xmalloc (sizeof (*closure));
618 *closure = (struct thread_closure)
621 .callback = callback,
622 .server_index = server_index,
624 return xpthread_create (NULL, thread_callback_wrapper, closure);
627 /* Process one UDP query. Return false if a termination requested has
630 server_thread_udp_process_one (struct resolv_test *obj, int server_index)
632 unsigned char query[512];
633 struct sockaddr_storage peer;
634 socklen_t peerlen = sizeof (peer);
635 size_t length = xrecvfrom (obj->servers[server_index].socket_udp,
636 query, sizeof (query), 0,
637 (struct sockaddr *) &peer, &peerlen);
638 /* Check for termination. */
640 bool termination_requested;
641 xpthread_mutex_lock (&obj->lock);
642 termination_requested = obj->termination_requested;
643 xpthread_mutex_unlock (&obj->lock);
644 if (termination_requested)
649 struct query_info qinfo;
650 parse_query (&qinfo, query, length);
651 if (test_verbose > 0)
653 if (test_verbose > 1)
654 printf ("info: UDP server %d: incoming query:"
655 " %zd bytes, %s/%u/%u, tnxid=0x%02x%02x\n",
656 server_index, length, qinfo.qname, qinfo.qclass, qinfo.qtype,
659 printf ("info: UDP server %d: incoming query:"
660 " %zd bytes, %s/%u/%u\n",
661 server_index, length, qinfo.qname, qinfo.qclass, qinfo.qtype);
664 struct resolv_response_context ctx =
667 .client_address = &peer,
668 .client_address_length = peerlen,
669 .query_buffer = query,
670 .query_length = length,
671 .server_index = server_index,
675 struct resolv_response_builder *b
676 = resolv_response_builder_allocate (query, length);
677 obj->config.response_callback
678 (&ctx, b, qinfo.qname, qinfo.qclass, qinfo.qtype);
683 printf ("info: UDP server %d: dropping response to %s/%u/%u\n",
684 server_index, qinfo.qname, qinfo.qclass, qinfo.qtype);
691 printf ("info: UDP server %d: sending response:"
692 " %zu bytes, RCODE %d (for %s/%u/%u)\n",
693 ctx.server_index, b->offset, b->buffer[3] & 0x0f,
694 qinfo.qname, qinfo.qclass, qinfo.qtype);
696 printf ("info: UDP server %d: sending response: %zu bytes"
698 server_index, b->offset,
699 qinfo.qname, qinfo.qclass, qinfo.qtype);
700 if (b->truncate_bytes > 0)
701 printf ("info: truncated by %u bytes\n", b->truncate_bytes);
703 resolv_response_send_udp (&ctx, b);
705 resolv_response_builder_free (b);
710 resolv_response_send_udp (const struct resolv_response_context *ctx,
711 struct resolv_response_builder *b)
713 TEST_VERIFY_EXIT (!ctx->tcp);
714 size_t to_send = b->offset;
715 if (to_send < b->truncate_bytes)
718 to_send -= b->truncate_bytes;
720 /* Ignore most errors here because the other end may have closed
722 if (sendto (ctx->test->servers[ctx->server_index].socket_udp,
723 b->buffer, to_send, 0,
724 ctx->client_address, ctx->client_address_length) < 0)
725 TEST_VERIFY_EXIT (errno != EBADF);
728 /* UDP thread_callback function. Variant for one thread per
731 server_thread_udp (struct resolv_test *obj, int server_index)
733 while (server_thread_udp_process_one (obj, server_index))
737 /* Single-threaded UDP processing function, for the single_thread_udp
740 server_thread_udp_single (void *closure)
742 struct resolv_test *obj = closure;
744 struct pollfd fds[resolv_max_test_servers];
745 for (int server_index = 0; server_index < resolv_max_test_servers;
747 if (obj->config.servers[server_index].disable_udp)
748 fds[server_index] = (struct pollfd) {.fd = -1};
751 fds[server_index] = (struct pollfd)
753 .fd = obj->servers[server_index].socket_udp,
757 /* Make the socket non-blocking. */
758 int flags = fcntl (obj->servers[server_index].socket_udp, F_GETFL, 0);
760 FAIL_EXIT1 ("fcntl (F_GETFL): %m");
762 if (fcntl (obj->servers[server_index].socket_udp, F_SETFL, flags) < 0)
763 FAIL_EXIT1 ("fcntl (F_SETFL): %m");
768 xpoll (fds, resolv_max_test_servers, -1);
769 for (int server_index = 0; server_index < resolv_max_test_servers;
771 if (fds[server_index].revents != 0)
773 if (!server_thread_udp_process_one (obj, server_index))
775 fds[server_index].revents = 0;
783 /* Start the single UDP handler thread (for the single_thread_udp
786 start_server_thread_udp_single (struct resolv_test *obj)
788 obj->thread_udp_single
789 = xpthread_create (NULL, server_thread_udp_single, obj);
792 /* Data describing a TCP client connect. */
793 struct tcp_thread_closure
795 struct resolv_test *obj;
800 /* Read a complete DNS query packet. If EOF_OK, an immediate
801 end-of-file condition is acceptable. */
803 read_fully (int fd, void *buf, size_t len, bool eof_ok)
805 const void *const end = buf + len;
808 ssize_t ret = read (fd, buf, end - buf);
813 support_record_failure ();
814 printf ("error: unexpected EOF on TCP connection\n");
820 if (!eof_ok || errno != ECONNRESET)
822 support_record_failure ();
823 printf ("error: TCP read: %m\n");
833 /* Write an array of iovecs. Terminate the process on failure. */
835 writev_fully (int fd, struct iovec *buffers, size_t count)
839 /* Skip zero-length write requests. */
840 if (buffers->iov_len == 0)
846 /* Try to rewrite the remaing buffers. */
847 ssize_t ret = writev (fd, buffers, count);
849 FAIL_EXIT1 ("writev: %m");
851 FAIL_EXIT1 ("writev: invalid return value zero");
852 /* Find the buffers that were successfully written. */
856 FAIL_EXIT1 ("internal writev consistency failure");
857 /* Current buffer was partially written. */
858 if (buffers->iov_len > (size_t) ret)
860 buffers->iov_base += ret;
861 buffers->iov_len -= ret;
866 ret -= buffers->iov_len;
867 buffers->iov_len = 0;
875 /* Thread callback for handling a single established TCP connection to
878 server_thread_tcp_client (void *arg)
880 struct tcp_thread_closure *closure = arg;
884 /* Read packet length. */
885 uint16_t query_length;
886 if (!read_fully (closure->client_socket,
887 &query_length, sizeof (query_length), true))
889 query_length = ntohs (query_length);
891 /* Read the packet. */
892 unsigned char *query_buffer = xmalloc (query_length);
893 read_fully (closure->client_socket, query_buffer, query_length, false);
895 struct query_info qinfo;
896 parse_query (&qinfo, query_buffer, query_length);
897 if (test_verbose > 0)
899 if (test_verbose > 1)
900 printf ("info: UDP server %d: incoming query:"
901 " %d bytes, %s/%u/%u, tnxid=0x%02x%02x\n",
902 closure->server_index, query_length,
903 qinfo.qname, qinfo.qclass, qinfo.qtype,
904 query_buffer[0], query_buffer[1]);
906 printf ("info: TCP server %d: incoming query:"
907 " %u bytes, %s/%u/%u\n",
908 closure->server_index, query_length,
909 qinfo.qname, qinfo.qclass, qinfo.qtype);
912 struct resolv_response_context ctx =
914 .test = closure->obj,
915 .query_buffer = query_buffer,
916 .query_length = query_length,
917 .server_index = closure->server_index,
921 struct resolv_response_builder *b
922 = resolv_response_builder_allocate (query_buffer, query_length);
923 closure->obj->config.response_callback
924 (&ctx, b, qinfo.qname, qinfo.qclass, qinfo.qtype);
929 printf ("info: TCP server %d: dropping response to %s/%u/%u\n",
930 closure->server_index,
931 qinfo.qname, qinfo.qclass, qinfo.qtype);
936 printf ("info: TCP server %d: sending response: %zu bytes"
938 closure->server_index, b->offset,
939 qinfo.qname, qinfo.qclass, qinfo.qtype);
940 uint16_t length = htons (b->offset);
941 size_t to_send = b->offset;
942 if (to_send < b->truncate_bytes)
945 to_send -= b->truncate_bytes;
946 struct iovec buffers[2] =
948 {&length, sizeof (length)},
951 writev_fully (closure->client_socket, buffers, 2);
953 bool close_flag = b->close;
954 resolv_response_builder_free (b);
960 xclose (closure->client_socket);
965 /* thread_callback for the TCP case. Accept connections and create a
966 new thread for each client. */
968 server_thread_tcp (struct resolv_test *obj, int server_index)
972 /* Get the client conenction. */
973 int client_socket = xaccept
974 (obj->servers[server_index].socket_tcp, NULL, NULL);
976 /* Check for termination. */
977 xpthread_mutex_lock (&obj->lock);
978 if (obj->termination_requested)
980 xpthread_mutex_unlock (&obj->lock);
981 xclose (client_socket);
984 xpthread_mutex_unlock (&obj->lock);
986 /* Spawn a new thread for handling this connection. */
987 struct tcp_thread_closure *closure = xmalloc (sizeof (*closure));
988 *closure = (struct tcp_thread_closure)
991 .server_index = server_index,
992 .client_socket = client_socket,
996 = xpthread_create (NULL, server_thread_tcp_client, closure);
997 /* TODO: We should keep track of this thread so that we can
998 block in resolv_test_end until it has exited. */
999 xpthread_detach (thr);
1003 /* Create UDP and TCP server sockets. */
1005 make_server_sockets (struct resolv_test_server *server)
1009 server->socket_udp = xsocket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
1010 server->socket_tcp = xsocket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
1012 /* Pick the address for the UDP socket. */
1013 server->address = (struct sockaddr_in)
1015 .sin_family = AF_INET,
1016 .sin_addr = {.s_addr = htonl (INADDR_LOOPBACK)}
1018 xbind (server->socket_udp,
1019 (struct sockaddr *)&server->address, sizeof (server->address));
1021 /* Retrieve the address. */
1022 socklen_t addrlen = sizeof (server->address);
1023 xgetsockname (server->socket_udp,
1024 (struct sockaddr *)&server->address, &addrlen);
1026 /* Bind the TCP socket to the same address. */
1029 xsetsockopt (server->socket_tcp, SOL_SOCKET, SO_REUSEADDR,
1032 if (bind (server->socket_tcp,
1033 (struct sockaddr *)&server->address,
1034 sizeof (server->address)) != 0)
1036 /* Port collision. The UDP bind succeeded, but the TCP BIND
1037 failed. We assume here that the kernel will pick the
1038 next local UDP address randomly. */
1039 if (errno == EADDRINUSE)
1041 xclose (server->socket_udp);
1042 xclose (server->socket_tcp);
1045 FAIL_EXIT1 ("TCP bind: %m");
1047 xlisten (server->socket_tcp, 5);
1052 /* Like make_server_sockets, but the caller supplies the address to
1055 make_server_sockets_for_address (struct resolv_test_server *server,
1056 const struct sockaddr *addr)
1058 server->socket_udp = xsocket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
1059 server->socket_tcp = xsocket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
1061 if (addr->sa_family == AF_INET)
1062 server->address = *(const struct sockaddr_in *) addr;
1064 /* We cannot store the server address in the socket. This should
1065 not matter if disable_redirect is used. */
1066 server->address = (struct sockaddr_in) { .sin_family = 0, };
1068 xbind (server->socket_udp,
1069 (struct sockaddr *)&server->address, sizeof (server->address));
1070 xbind (server->socket_tcp,
1071 (struct sockaddr *)&server->address, sizeof (server->address));
1072 xlisten (server->socket_tcp, 5);
1075 /* One-time initialization of NSS. */
1077 resolv_redirect_once (void)
1079 /* Only use nss_dns. */
1080 __nss_configure_lookup ("hosts", "dns");
1081 __nss_configure_lookup ("networks", "dns");
1082 /* Enter a network namespace for isolation and firewall state
1083 cleanup. The tests will still work if these steps fail, but they
1084 may be less reliable. */
1085 support_become_root ();
1086 support_enter_network_namespace ();
1088 pthread_once_t resolv_redirect_once_var = PTHREAD_ONCE_INIT;
1091 resolv_test_init (void)
1093 /* Perform one-time initialization of NSS. */
1094 xpthread_once (&resolv_redirect_once_var, resolv_redirect_once);
1097 /* Copy the search path from CONFIG.search to the _res object. */
1099 set_search_path (struct resolv_redirect_config config)
1101 memset (_res.defdname, 0, sizeof (_res.defdname));
1102 memset (_res.dnsrch, 0, sizeof (_res.dnsrch));
1104 char *current = _res.defdname;
1105 char *end = current + sizeof (_res.defdname);
1107 for (unsigned int i = 0;
1108 i < sizeof (config.search) / sizeof (config.search[0]); ++i)
1110 if (config.search[i] == NULL)
1113 size_t length = strlen (config.search[i]) + 1;
1114 size_t remaining = end - current;
1115 TEST_VERIFY_EXIT (length <= remaining);
1116 memcpy (current, config.search[i], length);
1117 _res.dnsrch[i] = current;
1122 struct resolv_test *
1123 resolv_test_start (struct resolv_redirect_config config)
1125 /* Apply configuration defaults. */
1126 if (config.nscount == 0)
1127 config.nscount = resolv_max_test_servers;
1129 struct resolv_test *obj = xmalloc (sizeof (*obj));
1130 *obj = (struct resolv_test) {
1132 .lock = PTHREAD_MUTEX_INITIALIZER,
1135 if (!config.disable_redirect)
1136 resolv_test_init ();
1138 /* Create all the servers, to reserve the necessary ports. */
1139 for (int server_index = 0; server_index < config.nscount; ++server_index)
1140 if (config.disable_redirect && config.server_address_overrides != NULL)
1141 make_server_sockets_for_address
1142 (obj->servers + server_index,
1143 config.server_address_overrides[server_index]);
1145 make_server_sockets (obj->servers + server_index);
1147 /* Start server threads. Disable the server ports, as
1149 for (int server_index = 0; server_index < config.nscount; ++server_index)
1151 struct resolv_test_server *server = obj->servers + server_index;
1152 if (config.servers[server_index].disable_udp)
1154 xclose (server->socket_udp);
1155 server->socket_udp = -1;
1157 else if (!config.single_thread_udp)
1158 server->thread_udp = start_server_thread (obj, server_index,
1160 if (config.servers[server_index].disable_tcp)
1162 xclose (server->socket_tcp);
1163 server->socket_tcp = -1;
1166 server->thread_tcp = start_server_thread (obj, server_index,
1169 if (config.single_thread_udp)
1170 start_server_thread_udp_single (obj);
1172 if (config.disable_redirect)
1177 /* Initialize libresolv. */
1178 TEST_VERIFY_EXIT (res_init () == 0);
1180 /* Disable IPv6 name server addresses. The code below only
1181 overrides the IPv4 addresses. */
1182 __res_iclose (&_res, true);
1183 _res._u._ext.nscount = 0;
1185 /* Redirect queries to the server socket. */
1188 printf ("info: old timeout value: %d\n", _res.retrans);
1189 printf ("info: old retry attempt value: %d\n", _res.retry);
1190 printf ("info: old _res.options: 0x%lx\n", _res.options);
1191 printf ("info: old _res.nscount value: %d\n", _res.nscount);
1192 printf ("info: old _res.ndots value: %d\n", _res.ndots);
1194 _res.retrans = timeout;
1196 _res.nscount = config.nscount;
1197 _res.options = RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH;
1201 printf ("info: new timeout value: %d\n", _res.retrans);
1202 printf ("info: new retry attempt value: %d\n", _res.retry);
1203 printf ("info: new _res.options: 0x%lx\n", _res.options);
1204 printf ("info: new _res.nscount value: %d\n", _res.nscount);
1205 printf ("info: new _res.ndots value: %d\n", _res.ndots);
1207 for (int server_index = 0; server_index < config.nscount; ++server_index)
1209 TEST_VERIFY_EXIT (obj->servers[server_index].address.sin_port != 0);
1210 _res.nsaddr_list[server_index] = obj->servers[server_index].address;
1215 (inet_ntop (AF_INET, &obj->servers[server_index].address.sin_addr,
1216 buf, sizeof (buf)) != NULL);
1217 printf ("info: server %d: %s/%u\n",
1219 htons (obj->servers[server_index].address.sin_port));
1223 set_search_path (config);
1229 resolv_test_end (struct resolv_test *obj)
1233 xpthread_mutex_lock (&obj->lock);
1234 obj->termination_requested = true;
1235 xpthread_mutex_unlock (&obj->lock);
1237 /* Send trigger packets to unblock the server threads. */
1238 for (int server_index = 0; server_index < obj->config.nscount;
1241 if (!obj->config.servers[server_index].disable_udp)
1243 int sock = xsocket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
1244 xsendto (sock, "", 1, 0,
1245 (struct sockaddr *) &obj->servers[server_index].address,
1246 sizeof (obj->servers[server_index].address));
1249 if (!obj->config.servers[server_index].disable_tcp)
1251 int sock = xsocket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
1253 (struct sockaddr *) &obj->servers[server_index].address,
1254 sizeof (obj->servers[server_index].address));
1259 if (obj->config.single_thread_udp)
1260 xpthread_join (obj->thread_udp_single);
1262 /* Wait for the server threads to terminate. */
1263 for (int server_index = 0; server_index < obj->config.nscount;
1266 if (!obj->config.servers[server_index].disable_udp)
1268 if (!obj->config.single_thread_udp)
1269 xpthread_join (obj->servers[server_index].thread_udp);
1270 xclose (obj->servers[server_index].socket_udp);
1272 if (!obj->config.servers[server_index].disable_tcp)
1274 xpthread_join (obj->servers[server_index].thread_tcp);
1275 xclose (obj->servers[server_index].socket_tcp);