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Diffstat (limited to 'support/resolv_test.c')
| -rw-r--r-- | support/resolv_test.c | 1202 |
1 files changed, 0 insertions, 1202 deletions
diff --git a/support/resolv_test.c b/support/resolv_test.c deleted file mode 100644 index 050cd7154b..0000000000 --- a/support/resolv_test.c +++ /dev/null @@ -1,1202 +0,0 @@ -/* DNS test framework and libresolv redirection. - Copyright (C) 2016-2017 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 <support/resolv_test.h> - -#include <arpa/inet.h> -#include <errno.h> -#include <fcntl.h> -#include <nss.h> -#include <resolv.h> -#include <search.h> -#include <stdlib.h> -#include <string.h> -#include <support/check.h> -#include <support/namespace.h> -#include <support/support.h> -#include <support/test-driver.h> -#include <support/xsocket.h> -#include <support/xthread.h> -#include <support/xunistd.h> -#include <sys/uio.h> -#include <unistd.h> - -/* Response builder. */ - -enum - { - max_response_length = 65536 - }; - -/* List of pointers to be freed. The hash table implementation - (struct hsearch_data) does not provide a way to deallocate all - objects, so this approach is used to avoid memory leaks. */ -struct to_be_freed -{ - struct to_be_freed *next; - void *ptr; -}; - -struct resolv_response_builder -{ - const unsigned char *query_buffer; - size_t query_length; - - size_t offset; /* Bytes written so far in buffer. */ - ns_sect section; /* Current section in the DNS packet. */ - unsigned int truncate_bytes; /* Bytes to remove at end of response. */ - bool drop; /* Discard generated response. */ - bool close; /* Close TCP client connection. */ - - /* Offset of the two-byte RDATA length field in the currently - written RDATA sub-structure. 0 if no RDATA is being written. */ - size_t current_rdata_offset; - - /* Hash table for locating targets for label compression. */ - struct hsearch_data compression_offsets; - /* List of pointers which need to be freed. Used for domain names - involved in label compression. */ - struct to_be_freed *to_be_freed; - - /* Must be last. Not zeroed for performance reasons. */ - unsigned char buffer[max_response_length]; -}; - -/* Response builder. */ - -/* Add a pointer to the list of pointers to be freed when B is - deallocated. */ -static void -response_push_pointer_to_free (struct resolv_response_builder *b, void *ptr) -{ - if (ptr == NULL) - return; - struct to_be_freed *e = xmalloc (sizeof (*e)); - *e = (struct to_be_freed) {b->to_be_freed, ptr}; - b->to_be_freed = e; -} - -void -resolv_response_init (struct resolv_response_builder *b, - struct resolv_response_flags flags) -{ - if (b->offset > 0) - FAIL_EXIT1 ("response_init: called at offset %zu", b->offset); - if (b->query_length < 12) - FAIL_EXIT1 ("response_init called for a query of size %zu", - b->query_length); - if (flags.rcode > 15) - FAIL_EXIT1 ("response_init: invalid RCODE %u", flags.rcode); - - /* Copy the transaction ID. */ - b->buffer[0] = b->query_buffer[0]; - b->buffer[1] = b->query_buffer[1]; - - /* Initialize the flags. */ - b->buffer[2] = 0x80; /* Mark as response. */ - b->buffer[2] |= b->query_buffer[2] & 0x01; /* Copy the RD bit. */ - if (flags.tc) - b->buffer[2] |= 0x02; - b->buffer[3] = 0x80 | flags.rcode; /* Always set RA. */ - - /* Fill in the initial section count values. */ - b->buffer[4] = flags.qdcount >> 8; - b->buffer[5] = flags.qdcount; - b->buffer[6] = flags.ancount >> 8; - b->buffer[7] = flags.ancount; - b->buffer[8] = flags.nscount >> 8; - b->buffer[9] = flags.nscount; - b->buffer[10] = flags.adcount >> 8; - b->buffer[11] = flags.adcount; - - b->offset = 12; -} - -void -resolv_response_section (struct resolv_response_builder *b, ns_sect section) -{ - if (b->offset == 0) - FAIL_EXIT1 ("resolv_response_section: response_init not called before"); - if (section < b->section) - FAIL_EXIT1 ("resolv_response_section: cannot go back to previous section"); - b->section = section; -} - -/* Add a single byte to B. */ -static inline void -response_add_byte (struct resolv_response_builder *b, unsigned char ch) -{ - if (b->offset == max_response_length) - FAIL_EXIT1 ("DNS response exceeds 64 KiB limit"); - b->buffer[b->offset] = ch; - ++b->offset; -} - -/* Add a 16-bit word VAL to B, in big-endian format. */ -static void -response_add_16 (struct resolv_response_builder *b, uint16_t val) -{ - response_add_byte (b, val >> 8); - response_add_byte (b, val); -} - -/* Increment the pers-section record counter in the packet header. */ -static void -response_count_increment (struct resolv_response_builder *b) -{ - unsigned int offset = b->section; - offset = 4 + 2 * offset; - ++b->buffer[offset + 1]; - if (b->buffer[offset + 1] == 0) - { - /* Carry. */ - ++b->buffer[offset]; - if (b->buffer[offset] == 0) - /* Overflow. */ - FAIL_EXIT1 ("too many records in section"); - } -} - -void -resolv_response_add_question (struct resolv_response_builder *b, - const char *name, uint16_t class, uint16_t type) -{ - if (b->offset == 0) - FAIL_EXIT1 ("resolv_response_add_question: " - "resolv_response_init not called"); - if (b->section != ns_s_qd) - FAIL_EXIT1 ("resolv_response_add_question: " - "must be called in the question section"); - - resolv_response_add_name (b, name); - response_add_16 (b, type); - response_add_16 (b, class); - - response_count_increment (b); -} - -void -resolv_response_add_name (struct resolv_response_builder *b, - const char *const origname) -{ - /* Normalized name. */ - char *name; - /* Normalized name with case preserved. */ - char *name_case; - { - size_t namelen = strlen (origname); - /* Remove trailing dots. FIXME: Handle trailing quoted dots. */ - while (namelen > 0 && origname[namelen - 1] == '.') - --namelen; - name = xmalloc (namelen + 1); - name_case = xmalloc (namelen + 1); - /* Copy and convert to lowercase. FIXME: This needs to normalize - escaping as well. */ - for (size_t i = 0; i < namelen; ++i) - { - char ch = origname[i]; - name_case[i] = ch; - if ('A' <= ch && ch <= 'Z') - ch = ch - 'A' + 'a'; - name[i] = ch; - } - name[namelen] = 0; - name_case[namelen] = 0; - } - char *name_start = name; - char *name_case_start = name_case; - - bool compression = false; - while (*name) - { - /* Search for a previous name we can reference. */ - ENTRY new_entry = - { - .key = name, - .data = (void *) (uintptr_t) b->offset, - }; - - /* If the label can be a compression target because it is at a - reachable offset, add it to the hash table. */ - ACTION action; - if (b->offset < (1 << 12)) - action = ENTER; - else - action = FIND; - - /* Search for known compression offsets in the hash table. */ - ENTRY *e; - if (hsearch_r (new_entry, action, &e, &b->compression_offsets) == 0) - { - if (action == FIND && errno == ESRCH) - /* Fall through. */ - e = NULL; - else - FAIL_EXIT1 ("hsearch_r failure in name compression: %m"); - } - - /* The name is known. Reference the previous location. */ - if (e != NULL && e->data != new_entry.data) - { - size_t old_offset = (uintptr_t) e->data; - response_add_byte (b, 0xC0 | (old_offset >> 8)); - response_add_byte (b, old_offset); - compression = true; - break; - } - - /* The name does not exist yet. Write one label. First, add - room for the label length. */ - size_t buffer_label_offset = b->offset; - response_add_byte (b, 0); - - /* Copy the label. */ - while (true) - { - char ch = *name_case; - if (ch == '\0') - break; - ++name; - ++name_case; - if (ch == '.') - break; - /* FIXME: Handle escaping. */ - response_add_byte (b, ch); - } - - /* Patch in the label length. */ - size_t label_length = b->offset - buffer_label_offset - 1; - if (label_length == 0) - FAIL_EXIT1 ("empty label in name compression: %s", origname); - if (label_length > 63) - FAIL_EXIT1 ("label too long in name compression: %s", origname); - b->buffer[buffer_label_offset] = label_length; - - /* Continue with the tail of the name and the next label. */ - } - - if (compression) - { - /* If we found an immediate match for the name, we have not put - it into the hash table, and can free it immediately. */ - if (name == name_start) - free (name_start); - else - response_push_pointer_to_free (b, name_start); - } - else - { - /* Terminate the sequence of labels. With compression, this is - implicit in the compression reference. */ - response_add_byte (b, 0); - response_push_pointer_to_free (b, name_start); - } - - free (name_case_start); -} - -void -resolv_response_open_record (struct resolv_response_builder *b, - const char *name, - uint16_t class, uint16_t type, uint32_t ttl) -{ - if (b->section == ns_s_qd) - FAIL_EXIT1 ("resolv_response_open_record called in question section"); - if (b->current_rdata_offset != 0) - FAIL_EXIT1 ("resolv_response_open_record called with open record"); - - resolv_response_add_name (b, name); - response_add_16 (b, type); - response_add_16 (b, class); - response_add_16 (b, ttl >> 16); - response_add_16 (b, ttl); - - b->current_rdata_offset = b->offset; - /* Add room for the RDATA length. */ - response_add_16 (b, 0); -} - - -void -resolv_response_close_record (struct resolv_response_builder *b) -{ - size_t rdata_offset = b->current_rdata_offset; - if (rdata_offset == 0) - FAIL_EXIT1 ("response_close_record called without open record"); - size_t rdata_length = b->offset - rdata_offset - 2; - if (rdata_length > 65535) - FAIL_EXIT1 ("RDATA length %zu exceeds limit", rdata_length); - b->buffer[rdata_offset] = rdata_length >> 8; - b->buffer[rdata_offset + 1] = rdata_length; - response_count_increment (b); - b->current_rdata_offset = 0; -} - -void -resolv_response_add_data (struct resolv_response_builder *b, - const void *data, size_t length) -{ - size_t remaining = max_response_length - b->offset; - if (remaining < length) - FAIL_EXIT1 ("resolv_response_add_data: not enough room for %zu bytes", - length); - memcpy (b->buffer + b->offset, data, length); - b->offset += length; -} - -void -resolv_response_drop (struct resolv_response_builder *b) -{ - b->drop = true; -} - -void -resolv_response_close (struct resolv_response_builder *b) -{ - b->close = true; -} - -void -resolv_response_truncate_data (struct resolv_response_builder *b, size_t count) -{ - if (count > 65535) - FAIL_EXIT1 ("resolv_response_truncate_data: argument too large: %zu", - count); - b->truncate_bytes = count; -} - - -size_t -resolv_response_length (const struct resolv_response_builder *b) -{ - return b->offset; -} - -unsigned char * -resolv_response_buffer (const struct resolv_response_builder *b) -{ - unsigned char *result = xmalloc (b->offset); - memcpy (result, b->buffer, b->offset); - return result; -} - -static struct resolv_response_builder * -response_builder_allocate - (const unsigned char *query_buffer, size_t query_length) -{ - struct resolv_response_builder *b = xmalloc (sizeof (*b)); - memset (b, 0, offsetof (struct resolv_response_builder, buffer)); - b->query_buffer = query_buffer; - b->query_length = query_length; - TEST_VERIFY_EXIT (hcreate_r (10000, &b->compression_offsets) != 0); - return b; -} - -static void -response_builder_free (struct resolv_response_builder *b) -{ - struct to_be_freed *current = b->to_be_freed; - while (current != NULL) - { - struct to_be_freed *next = current->next; - free (current->ptr); - free (current); - current = next; - } - hdestroy_r (&b->compression_offsets); - free (b); -} - -/* DNS query processing. */ - -/* Data extracted from the question section of a DNS packet. */ -struct query_info -{ - char qname[MAXDNAME]; - uint16_t qclass; - uint16_t qtype; - struct resolv_edns_info edns; -}; - -/* Update *INFO from the specified DNS packet. */ -static void -parse_query (struct query_info *info, - const unsigned char *buffer, size_t length) -{ - HEADER hd; - _Static_assert (sizeof (hd) == 12, "DNS header size"); - if (length < sizeof (hd)) - FAIL_EXIT1 ("malformed DNS query: too short: %zu bytes", length); - memcpy (&hd, buffer, sizeof (hd)); - - if (ntohs (hd.qdcount) != 1) - FAIL_EXIT1 ("malformed DNS query: wrong question count: %d", - (int) ntohs (hd.qdcount)); - if (ntohs (hd.ancount) != 0) - FAIL_EXIT1 ("malformed DNS query: wrong answer count: %d", - (int) ntohs (hd.ancount)); - if (ntohs (hd.nscount) != 0) - FAIL_EXIT1 ("malformed DNS query: wrong authority count: %d", - (int) ntohs (hd.nscount)); - if (ntohs (hd.arcount) > 1) - FAIL_EXIT1 ("malformed DNS query: wrong additional count: %d", - (int) ntohs (hd.arcount)); - - int ret = dn_expand (buffer, buffer + length, buffer + sizeof (hd), - info->qname, sizeof (info->qname)); - if (ret < 0) - FAIL_EXIT1 ("malformed DNS query: cannot uncompress QNAME"); - - /* Obtain QTYPE and QCLASS. */ - size_t remaining = length - (12 + ret); - struct - { - uint16_t qtype; - uint16_t qclass; - } qtype_qclass; - if (remaining < sizeof (qtype_qclass)) - FAIL_EXIT1 ("malformed DNS query: " - "query lacks QCLASS/QTYPE, QNAME: %s", info->qname); - memcpy (&qtype_qclass, buffer + 12 + ret, sizeof (qtype_qclass)); - info->qclass = ntohs (qtype_qclass.qclass); - info->qtype = ntohs (qtype_qclass.qtype); - - memset (&info->edns, 0, sizeof (info->edns)); - if (ntohs (hd.arcount) > 0) - { - /* Parse EDNS record. */ - struct __attribute__ ((packed, aligned (1))) - { - uint8_t root; - uint16_t rtype; - uint16_t payload; - uint8_t edns_extended_rcode; - uint8_t edns_version; - uint16_t flags; - uint16_t rdatalen; - } rr; - _Static_assert (sizeof (rr) == 11, "EDNS record size"); - - if (remaining < 4 + sizeof (rr)) - FAIL_EXIT1 ("mailformed DNS query: no room for EDNS record"); - memcpy (&rr, buffer + 12 + ret + 4, sizeof (rr)); - if (rr.root != 0) - FAIL_EXIT1 ("malformed DNS query: invalid OPT RNAME: %d\n", rr.root); - if (rr.rtype != htons (41)) - FAIL_EXIT1 ("malformed DNS query: invalid OPT type: %d\n", - ntohs (rr.rtype)); - info->edns.active = true; - info->edns.extended_rcode = rr.edns_extended_rcode; - info->edns.version = rr.edns_version; - info->edns.flags = ntohs (rr.flags); - info->edns.payload_size = ntohs (rr.payload); - } -} - - -/* Main testing framework. */ - -/* Per-server information. One struct is allocated for each test - server. */ -struct resolv_test_server -{ - /* Local address of the server. UDP and TCP use the same port. */ - struct sockaddr_in address; - - /* File descriptor of the UDP server, or -1 if this server is - disabled. */ - int socket_udp; - - /* File descriptor of the TCP server, or -1 if this server is - disabled. */ - int socket_tcp; - - /* Counter of the number of responses processed so far. */ - size_t response_number; - - /* Thread handles for the server threads (if not disabled in the - configuration). */ - pthread_t thread_udp; - pthread_t thread_tcp; -}; - -/* Main struct for keeping track of libresolv redirection and - testing. */ -struct resolv_test -{ - /* After initialization, any access to the struct must be performed - while this lock is acquired. */ - pthread_mutex_t lock; - - /* Data for each test server. */ - struct resolv_test_server servers[resolv_max_test_servers]; - - /* Used if config.single_thread_udp is true. */ - pthread_t thread_udp_single; - - struct resolv_redirect_config config; - bool termination_requested; -}; - -/* Function implementing a server thread. */ -typedef void (*thread_callback) (struct resolv_test *, int server_index); - -/* Storage for thread-specific data, for passing to the - thread_callback function. */ -struct thread_closure -{ - struct resolv_test *obj; /* Current test object. */ - thread_callback callback; /* Function to call. */ - int server_index; /* Index of the implemented server. */ -}; - -/* Wrap response_callback as a function which can be passed to - pthread_create. */ -static void * -thread_callback_wrapper (void *arg) -{ - struct thread_closure *closure = arg; - closure->callback (closure->obj, closure->server_index); - free (closure); - return NULL; -} - -/* Start a server thread for the specified SERVER_INDEX, implemented - by CALLBACK. */ -static pthread_t -start_server_thread (struct resolv_test *obj, int server_index, - thread_callback callback) -{ - struct thread_closure *closure = xmalloc (sizeof (*closure)); - *closure = (struct thread_closure) - { - .obj = obj, - .callback = callback, - .server_index = server_index, - }; - return xpthread_create (NULL, thread_callback_wrapper, closure); -} - -/* Process one UDP query. Return false if a termination requested has - been detected. */ -static bool -server_thread_udp_process_one (struct resolv_test *obj, int server_index) -{ - unsigned char query[512]; - struct sockaddr_storage peer; - socklen_t peerlen = sizeof (peer); - size_t length = xrecvfrom (obj->servers[server_index].socket_udp, - query, sizeof (query), 0, - (struct sockaddr *) &peer, &peerlen); - /* Check for termination. */ - { - bool termination_requested; - xpthread_mutex_lock (&obj->lock); - termination_requested = obj->termination_requested; - xpthread_mutex_unlock (&obj->lock); - if (termination_requested) - return false; - } - - - struct query_info qinfo; - parse_query (&qinfo, query, length); - if (test_verbose > 0) - { - if (test_verbose > 1) - printf ("info: UDP server %d: incoming query:" - " %zd bytes, %s/%u/%u, tnxid=0x%02x%02x\n", - server_index, length, qinfo.qname, qinfo.qclass, qinfo.qtype, - query[0], query[1]); - else - printf ("info: UDP server %d: incoming query:" - " %zd bytes, %s/%u/%u\n", - server_index, length, qinfo.qname, qinfo.qclass, qinfo.qtype); - } - - struct resolv_response_context ctx = - { - .query_buffer = query, - .query_length = length, - .server_index = server_index, - .tcp = false, - .edns = qinfo.edns, - }; - struct resolv_response_builder *b = response_builder_allocate (query, length); - obj->config.response_callback - (&ctx, b, qinfo.qname, qinfo.qclass, qinfo.qtype); - - if (b->drop) - { - if (test_verbose) - printf ("info: UDP server %d: dropping response to %s/%u/%u\n", - server_index, qinfo.qname, qinfo.qclass, qinfo.qtype); - } - else - { - if (test_verbose) - { - if (b->offset >= 12) - printf ("info: UDP server %d: sending response:" - " %zu bytes, RCODE %d (for %s/%u/%u)\n", - server_index, b->offset, b->buffer[3] & 0x0f, - qinfo.qname, qinfo.qclass, qinfo.qtype); - else - printf ("info: UDP server %d: sending response: %zu bytes" - " (for %s/%u/%u)\n", - server_index, b->offset, - qinfo.qname, qinfo.qclass, qinfo.qtype); - if (b->truncate_bytes > 0) - printf ("info: truncated by %u bytes\n", b->truncate_bytes); - } - size_t to_send = b->offset; - if (to_send < b->truncate_bytes) - to_send = 0; - else - to_send -= b->truncate_bytes; - - /* Ignore most errors here because the other end may have closed - the socket. */ - if (sendto (obj->servers[server_index].socket_udp, - b->buffer, to_send, 0, - (struct sockaddr *) &peer, peerlen) < 0) - TEST_VERIFY_EXIT (errno != EBADF); - } - response_builder_free (b); - return true; -} - -/* UDP thread_callback function. Variant for one thread per - server. */ -static void -server_thread_udp (struct resolv_test *obj, int server_index) -{ - while (server_thread_udp_process_one (obj, server_index)) - ; -} - -/* Single-threaded UDP processing function, for the single_thread_udp - case. */ -static void * -server_thread_udp_single (void *closure) -{ - struct resolv_test *obj = closure; - - struct pollfd fds[resolv_max_test_servers]; - for (int server_index = 0; server_index < resolv_max_test_servers; - ++server_index) - if (obj->config.servers[server_index].disable_udp) - fds[server_index] = (struct pollfd) {.fd = -1}; - else - { - fds[server_index] = (struct pollfd) - { - .fd = obj->servers[server_index].socket_udp, - .events = POLLIN - }; - - /* Make the socket non-blocking. */ - int flags = fcntl (obj->servers[server_index].socket_udp, F_GETFL, 0); - if (flags < 0) - FAIL_EXIT1 ("fcntl (F_GETFL): %m"); - flags |= O_NONBLOCK; - if (fcntl (obj->servers[server_index].socket_udp, F_SETFL, flags) < 0) - FAIL_EXIT1 ("fcntl (F_SETFL): %m"); - } - - while (true) - { - xpoll (fds, resolv_max_test_servers, -1); - for (int server_index = 0; server_index < resolv_max_test_servers; - ++server_index) - if (fds[server_index].revents != 0) - { - if (!server_thread_udp_process_one (obj, server_index)) - goto out; - fds[server_index].revents = 0; - } - } - - out: - return NULL; -} - -/* Start the single UDP handler thread (for the single_thread_udp - case). */ -static void -start_server_thread_udp_single (struct resolv_test *obj) -{ - obj->thread_udp_single - = xpthread_create (NULL, server_thread_udp_single, obj); -} - -/* Data describing a TCP client connect. */ -struct tcp_thread_closure -{ - struct resolv_test *obj; - int server_index; - int client_socket; -}; - -/* Read a complete DNS query packet. If EOF_OK, an immediate - end-of-file condition is acceptable. */ -static bool -read_fully (int fd, void *buf, size_t len, bool eof_ok) -{ - const void *const end = buf + len; - while (buf < end) - { - ssize_t ret = read (fd, buf, end - buf); - if (ret == 0) - { - if (!eof_ok) - { - support_record_failure (); - printf ("error: unexpected EOF on TCP connection\n"); - } - return false; - } - else if (ret < 0) - { - if (!eof_ok || errno != ECONNRESET) - { - support_record_failure (); - printf ("error: TCP read: %m\n"); - } - return false; - } - buf += ret; - eof_ok = false; - } - return true; -} - -/* Write an array of iovecs. Terminate the process on failure. */ -static void -writev_fully (int fd, struct iovec *buffers, size_t count) -{ - while (count > 0) - { - /* Skip zero-length write requests. */ - if (buffers->iov_len == 0) - { - ++buffers; - --count; - continue; - } - /* Try to rewrite the remaing buffers. */ - ssize_t ret = writev (fd, buffers, count); - if (ret < 0) - FAIL_EXIT1 ("writev: %m"); - if (ret == 0) - FAIL_EXIT1 ("writev: invalid return value zero"); - /* Find the buffers that were successfully written. */ - while (ret > 0) - { - if (count == 0) - FAIL_EXIT1 ("internal writev consistency failure"); - /* Current buffer was partially written. */ - if (buffers->iov_len > (size_t) ret) - { - buffers->iov_base += ret; - buffers->iov_len -= ret; - ret = 0; - } - else - { - ret -= buffers->iov_len; - buffers->iov_len = 0; - ++buffers; - --count; - } - } - } -} - -/* Thread callback for handling a single established TCP connection to - a client. */ -static void * -server_thread_tcp_client (void *arg) -{ - struct tcp_thread_closure *closure = arg; - - while (true) - { - /* Read packet length. */ - uint16_t query_length; - if (!read_fully (closure->client_socket, - &query_length, sizeof (query_length), true)) - break; - query_length = ntohs (query_length); - - /* Read the packet. */ - unsigned char *query_buffer = xmalloc (query_length); - read_fully (closure->client_socket, query_buffer, query_length, false); - - struct query_info qinfo; - parse_query (&qinfo, query_buffer, query_length); - if (test_verbose > 0) - { - if (test_verbose > 1) - printf ("info: UDP server %d: incoming query:" - " %d bytes, %s/%u/%u, tnxid=0x%02x%02x\n", - closure->server_index, query_length, - qinfo.qname, qinfo.qclass, qinfo.qtype, - query_buffer[0], query_buffer[1]); - else - printf ("info: TCP server %d: incoming query:" - " %u bytes, %s/%u/%u\n", - closure->server_index, query_length, - qinfo.qname, qinfo.qclass, qinfo.qtype); - } - - struct resolv_response_context ctx = - { - .query_buffer = query_buffer, - .query_length = query_length, - .server_index = closure->server_index, - .tcp = true, - .edns = qinfo.edns, - }; - struct resolv_response_builder *b = response_builder_allocate - (query_buffer, query_length); - closure->obj->config.response_callback - (&ctx, b, qinfo.qname, qinfo.qclass, qinfo.qtype); - - if (b->drop) - { - if (test_verbose) - printf ("info: TCP server %d: dropping response to %s/%u/%u\n", - closure->server_index, - qinfo.qname, qinfo.qclass, qinfo.qtype); - } - else - { - if (test_verbose) - printf ("info: TCP server %d: sending response: %zu bytes" - " (for %s/%u/%u)\n", - closure->server_index, b->offset, - qinfo.qname, qinfo.qclass, qinfo.qtype); - uint16_t length = htons (b->offset); - size_t to_send = b->offset; - if (to_send < b->truncate_bytes) - to_send = 0; - else - to_send -= b->truncate_bytes; - struct iovec buffers[2] = - { - {&length, sizeof (length)}, - {b->buffer, to_send} - }; - writev_fully (closure->client_socket, buffers, 2); - } - bool close_flag = b->close; - response_builder_free (b); - free (query_buffer); - if (close_flag) - break; - } - - xclose (closure->client_socket); - free (closure); - return NULL; -} - -/* thread_callback for the TCP case. Accept connections and create a - new thread for each client. */ -static void -server_thread_tcp (struct resolv_test *obj, int server_index) -{ - while (true) - { - /* Get the client conenction. */ - int client_socket = xaccept - (obj->servers[server_index].socket_tcp, NULL, NULL); - - /* Check for termination. */ - xpthread_mutex_lock (&obj->lock); - if (obj->termination_requested) - { - xpthread_mutex_unlock (&obj->lock); - xclose (client_socket); - break; - } - xpthread_mutex_unlock (&obj->lock); - - /* Spawn a new thread for handling this connection. */ - struct tcp_thread_closure *closure = xmalloc (sizeof (*closure)); - *closure = (struct tcp_thread_closure) - { - .obj = obj, - .server_index = server_index, - .client_socket = client_socket, - }; - - pthread_t thr - = xpthread_create (NULL, server_thread_tcp_client, closure); - /* TODO: We should keep track of this thread so that we can - block in resolv_test_end until it has exited. */ - xpthread_detach (thr); - } -} - -/* Create UDP and TCP server sockets. */ -static void -make_server_sockets (struct resolv_test_server *server) -{ - while (true) - { - server->socket_udp = xsocket (AF_INET, SOCK_DGRAM, IPPROTO_UDP); - server->socket_tcp = xsocket (AF_INET, SOCK_STREAM, IPPROTO_TCP); - - /* Pick the address for the UDP socket. */ - server->address = (struct sockaddr_in) - { - .sin_family = AF_INET, - .sin_addr = {.s_addr = htonl (INADDR_LOOPBACK)} - }; - xbind (server->socket_udp, - (struct sockaddr *)&server->address, sizeof (server->address)); - - /* Retrieve the address. */ - socklen_t addrlen = sizeof (server->address); - xgetsockname (server->socket_udp, - (struct sockaddr *)&server->address, &addrlen); - - /* Bind the TCP socket to the same address. */ - { - int on = 1; - xsetsockopt (server->socket_tcp, SOL_SOCKET, SO_REUSEADDR, - &on, sizeof (on)); - } - if (bind (server->socket_tcp, - (struct sockaddr *)&server->address, - sizeof (server->address)) != 0) - { - /* Port collision. The UDP bind succeeded, but the TCP BIND - failed. We assume here that the kernel will pick the - next local UDP address randomly. */ - if (errno == EADDRINUSE) - { - xclose (server->socket_udp); - xclose (server->socket_tcp); - continue; - } - FAIL_EXIT1 ("TCP bind: %m"); - } - xlisten (server->socket_tcp, 5); - break; - } -} - -/* One-time initialization of NSS. */ -static void -resolv_redirect_once (void) -{ - /* Only use nss_dns. */ - __nss_configure_lookup ("hosts", "dns"); - __nss_configure_lookup ("networks", "dns"); - /* Enter a network namespace for isolation and firewall state - cleanup. The tests will still work if these steps fail, but they - may be less reliable. */ - support_become_root (); - support_enter_network_namespace (); -} -pthread_once_t resolv_redirect_once_var = PTHREAD_ONCE_INIT; - -void -resolv_test_init (void) -{ - /* Perform one-time initialization of NSS. */ - xpthread_once (&resolv_redirect_once_var, resolv_redirect_once); -} - -/* Copy the search path from CONFIG.search to the _res object. */ -static void -set_search_path (struct resolv_redirect_config config) -{ - memset (_res.defdname, 0, sizeof (_res.defdname)); - memset (_res.dnsrch, 0, sizeof (_res.dnsrch)); - - char *current = _res.defdname; - char *end = current + sizeof (_res.defdname); - - for (unsigned int i = 0; - i < sizeof (config.search) / sizeof (config.search[0]); ++i) - { - if (config.search[i] == NULL) - continue; - - size_t length = strlen (config.search[i]) + 1; - size_t remaining = end - current; - TEST_VERIFY_EXIT (length <= remaining); - memcpy (current, config.search[i], length); - _res.dnsrch[i] = current; - current += length; - } -} - -struct resolv_test * -resolv_test_start (struct resolv_redirect_config config) -{ - /* Apply configuration defaults. */ - if (config.nscount == 0) - config.nscount = resolv_max_test_servers; - - struct resolv_test *obj = xmalloc (sizeof (*obj)); - *obj = (struct resolv_test) { - .config = config, - .lock = PTHREAD_MUTEX_INITIALIZER, - }; - - resolv_test_init (); - - /* Create all the servers, to reserve the necessary ports. */ - for (int server_index = 0; server_index < config.nscount; ++server_index) - make_server_sockets (obj->servers + server_index); - - /* Start server threads. Disable the server ports, as - requested. */ - for (int server_index = 0; server_index < config.nscount; ++server_index) - { - struct resolv_test_server *server = obj->servers + server_index; - if (config.servers[server_index].disable_udp) - { - xclose (server->socket_udp); - server->socket_udp = -1; - } - else if (!config.single_thread_udp) - server->thread_udp = start_server_thread (obj, server_index, - server_thread_udp); - if (config.servers[server_index].disable_tcp) - { - xclose (server->socket_tcp); - server->socket_tcp = -1; - } - else - server->thread_tcp = start_server_thread (obj, server_index, - server_thread_tcp); - } - if (config.single_thread_udp) - start_server_thread_udp_single (obj); - - int timeout = 1; - - /* Initialize libresolv. */ - TEST_VERIFY_EXIT (res_init () == 0); - - /* Disable IPv6 name server addresses. The code below only - overrides the IPv4 addresses. */ - __res_iclose (&_res, true); - _res._u._ext.nscount = 0; - - /* Redirect queries to the server socket. */ - if (test_verbose) - { - printf ("info: old timeout value: %d\n", _res.retrans); - printf ("info: old retry attempt value: %d\n", _res.retry); - printf ("info: old _res.options: 0x%lx\n", _res.options); - printf ("info: old _res.nscount value: %d\n", _res.nscount); - printf ("info: old _res.ndots value: %d\n", _res.ndots); - } - _res.retrans = timeout; - _res.retry = 4; - _res.nscount = config.nscount; - _res.options = RES_INIT | RES_RECURSE | RES_DEFNAMES | RES_DNSRCH; - _res.ndots = 1; - if (test_verbose) - { - printf ("info: new timeout value: %d\n", _res.retrans); - printf ("info: new retry attempt value: %d\n", _res.retry); - printf ("info: new _res.options: 0x%lx\n", _res.options); - printf ("info: new _res.nscount value: %d\n", _res.nscount); - printf ("info: new _res.ndots value: %d\n", _res.ndots); - } - for (int server_index = 0; server_index < config.nscount; ++server_index) - { - _res.nsaddr_list[server_index] = obj->servers[server_index].address; - if (test_verbose) - { - char buf[256]; - TEST_VERIFY_EXIT - (inet_ntop (AF_INET, &obj->servers[server_index].address.sin_addr, - buf, sizeof (buf)) != NULL); - printf ("info: server %d: %s/%u\n", - server_index, buf, - htons (obj->servers[server_index].address.sin_port)); - } - } - - set_search_path (config); - - return obj; -} - -void -resolv_test_end (struct resolv_test *obj) -{ - res_close (); - - xpthread_mutex_lock (&obj->lock); - obj->termination_requested = true; - xpthread_mutex_unlock (&obj->lock); - - /* Send trigger packets to unblock the server threads. */ - for (int server_index = 0; server_index < obj->config.nscount; - ++server_index) - { - if (!obj->config.servers[server_index].disable_udp) - { - int sock = xsocket (AF_INET, SOCK_DGRAM, IPPROTO_UDP); - xsendto (sock, "", 1, 0, - (struct sockaddr *) &obj->servers[server_index].address, - sizeof (obj->servers[server_index].address)); - xclose (sock); - } - if (!obj->config.servers[server_index].disable_tcp) - { - int sock = xsocket (AF_INET, SOCK_STREAM, IPPROTO_TCP); - xconnect (sock, - (struct sockaddr *) &obj->servers[server_index].address, - sizeof (obj->servers[server_index].address)); - xclose (sock); - } - } - - if (obj->config.single_thread_udp) - xpthread_join (obj->thread_udp_single); - - /* Wait for the server threads to terminate. */ - for (int server_index = 0; server_index < obj->config.nscount; - ++server_index) - { - if (!obj->config.servers[server_index].disable_udp) - { - if (!obj->config.single_thread_udp) - xpthread_join (obj->servers[server_index].thread_udp); - xclose (obj->servers[server_index].socket_udp); - } - if (!obj->config.servers[server_index].disable_tcp) - { - xpthread_join (obj->servers[server_index].thread_tcp); - xclose (obj->servers[server_index].socket_tcp); - } - } - - free (obj); -} |