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4848 lines
130 KiB
4848 lines
130 KiB
/* Copyright 2006-2007 Niels Provos
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* Copyright 2007-2012 Nick Mathewson and Niels Provos
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Based on software by Adam Langly. Adam's original message:
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*
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* Async DNS Library
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* Adam Langley <agl@imperialviolet.org>
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* http://www.imperialviolet.org/eventdns.html
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* Public Domain code
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*
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* This software is Public Domain. To view a copy of the public domain dedication,
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* visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
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* Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
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*
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* I ask and expect, but do not require, that all derivative works contain an
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* attribution similar to:
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* Parts developed by Adam Langley <agl@imperialviolet.org>
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*
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* You may wish to replace the word "Parts" with something else depending on
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* the amount of original code.
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*
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* (Derivative works does not include programs which link against, run or include
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* the source verbatim in their source distributions)
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*
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* Version: 0.1b
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*/
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#include "event2/event-config.h"
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#include "evconfig-private.h"
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#include <sys/types.h>
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#ifndef _FORTIFY_SOURCE
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#define _FORTIFY_SOURCE 3
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#endif
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#include <string.h>
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#include <fcntl.h>
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#ifdef EVENT__HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#ifdef EVENT__HAVE_STDINT_H
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#include <stdint.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#ifdef EVENT__HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <limits.h>
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#include <sys/stat.h>
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#include <stdio.h>
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#include <stdarg.h>
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#ifdef _WIN32
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#include <winsock2.h>
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#include <winerror.h>
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#include <ws2tcpip.h>
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#ifndef _WIN32_IE
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#define _WIN32_IE 0x400
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#endif
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#include <shlobj.h>
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#endif
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#include "event2/dns.h"
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#include "event2/dns_struct.h"
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#include "event2/dns_compat.h"
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#include "event2/util.h"
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#include "event2/event.h"
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#include "event2/event_struct.h"
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#include "event2/thread.h"
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#include "defer-internal.h"
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#include "log-internal.h"
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#include "mm-internal.h"
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#include "strlcpy-internal.h"
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#include "ipv6-internal.h"
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#include "util-internal.h"
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#include "evthread-internal.h"
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#ifdef _WIN32
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#include <ctype.h>
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#include <winsock2.h>
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#include <windows.h>
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#include <iphlpapi.h>
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#include <io.h>
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#else
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#endif
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#ifdef EVENT__HAVE_NETINET_IN6_H
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#include <netinet/in6.h>
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#endif
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#define EVDNS_LOG_DEBUG EVENT_LOG_DEBUG
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#define EVDNS_LOG_WARN EVENT_LOG_WARN
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#define EVDNS_LOG_MSG EVENT_LOG_MSG
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#ifndef HOST_NAME_MAX
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#define HOST_NAME_MAX 255
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#endif
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#include <stdio.h>
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#undef MIN
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#define MIN(a,b) ((a)<(b)?(a):(b))
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#define ASSERT_VALID_REQUEST(req) \
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EVUTIL_ASSERT((req)->handle && (req)->handle->current_req == (req))
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#define u64 ev_uint64_t
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#define u32 ev_uint32_t
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#define u16 ev_uint16_t
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#define u8 ev_uint8_t
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/* maximum number of addresses from a single packet */
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/* that we bother recording */
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#define MAX_V4_ADDRS 32
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#define MAX_V6_ADDRS 32
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#define TYPE_A EVDNS_TYPE_A
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#define TYPE_CNAME 5
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#define TYPE_PTR EVDNS_TYPE_PTR
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#define TYPE_SOA EVDNS_TYPE_SOA
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#define TYPE_AAAA EVDNS_TYPE_AAAA
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#define CLASS_INET EVDNS_CLASS_INET
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/* Persistent handle. We keep this separate from 'struct request' since we
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* need some object to last for as long as an evdns_request is outstanding so
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* that it can be canceled, whereas a search request can lead to multiple
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* 'struct request' instances being created over its lifetime. */
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struct evdns_request {
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struct request *current_req;
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struct evdns_base *base;
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int pending_cb; /* Waiting for its callback to be invoked; not
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* owned by event base any more. */
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/* elements used by the searching code */
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int search_index;
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struct search_state *search_state;
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char *search_origname; /* needs to be free()ed */
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int search_flags;
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};
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struct request {
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u8 *request; /* the dns packet data */
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u8 request_type; /* TYPE_PTR or TYPE_A or TYPE_AAAA */
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unsigned int request_len;
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int reissue_count;
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int tx_count; /* the number of times that this packet has been sent */
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void *user_pointer; /* the pointer given to us for this request */
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evdns_callback_type user_callback;
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struct nameserver *ns; /* the server which we last sent it */
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/* these objects are kept in a circular list */
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/* XXX We could turn this into a CIRCLEQ. */
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struct request *next, *prev;
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struct event timeout_event;
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u16 trans_id; /* the transaction id */
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unsigned request_appended :1; /* true if the request pointer is data which follows this struct */
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unsigned transmit_me :1; /* needs to be transmitted */
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/* XXXX This is a horrible hack. */
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char **put_cname_in_ptr; /* store the cname here if we get one. */
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struct evdns_base *base;
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struct evdns_request *handle;
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};
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struct reply {
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unsigned int type;
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unsigned int have_answer : 1;
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union {
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struct {
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u32 addrcount;
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u32 addresses[MAX_V4_ADDRS];
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} a;
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struct {
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u32 addrcount;
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struct in6_addr addresses[MAX_V6_ADDRS];
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} aaaa;
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struct {
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char name[HOST_NAME_MAX];
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} ptr;
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} data;
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};
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struct nameserver {
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evutil_socket_t socket; /* a connected UDP socket */
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struct sockaddr_storage address;
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ev_socklen_t addrlen;
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int failed_times; /* number of times which we have given this server a chance */
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int timedout; /* number of times in a row a request has timed out */
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struct event event;
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/* these objects are kept in a circular list */
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struct nameserver *next, *prev;
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struct event timeout_event; /* used to keep the timeout for */
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/* when we next probe this server. */
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/* Valid if state == 0 */
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/* Outstanding probe request for this nameserver, if any */
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struct evdns_request *probe_request;
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char state; /* zero if we think that this server is down */
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char choked; /* true if we have an EAGAIN from this server's socket */
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char write_waiting; /* true if we are waiting for EV_WRITE events */
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struct evdns_base *base;
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/* Number of currently inflight requests: used
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* to track when we should add/del the event. */
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int requests_inflight;
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};
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/* Represents a local port where we're listening for DNS requests. Right now, */
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/* only UDP is supported. */
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struct evdns_server_port {
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evutil_socket_t socket; /* socket we use to read queries and write replies. */
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int refcnt; /* reference count. */
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char choked; /* Are we currently blocked from writing? */
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char closing; /* Are we trying to close this port, pending writes? */
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evdns_request_callback_fn_type user_callback; /* Fn to handle requests */
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void *user_data; /* Opaque pointer passed to user_callback */
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struct event event; /* Read/write event */
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/* circular list of replies that we want to write. */
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struct server_request *pending_replies;
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struct event_base *event_base;
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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void *lock;
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#endif
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};
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/* Represents part of a reply being built. (That is, a single RR.) */
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struct server_reply_item {
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struct server_reply_item *next; /* next item in sequence. */
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char *name; /* name part of the RR */
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u16 type; /* The RR type */
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u16 class; /* The RR class (usually CLASS_INET) */
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u32 ttl; /* The RR TTL */
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char is_name; /* True iff data is a label */
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u16 datalen; /* Length of data; -1 if data is a label */
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void *data; /* The contents of the RR */
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};
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/* Represents a request that we've received as a DNS server, and holds */
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/* the components of the reply as we're constructing it. */
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struct server_request {
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/* Pointers to the next and previous entries on the list of replies */
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/* that we're waiting to write. Only set if we have tried to respond */
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/* and gotten EAGAIN. */
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struct server_request *next_pending;
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struct server_request *prev_pending;
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u16 trans_id; /* Transaction id. */
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struct evdns_server_port *port; /* Which port received this request on? */
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struct sockaddr_storage addr; /* Where to send the response */
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ev_socklen_t addrlen; /* length of addr */
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int n_answer; /* how many answer RRs have been set? */
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int n_authority; /* how many authority RRs have been set? */
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int n_additional; /* how many additional RRs have been set? */
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struct server_reply_item *answer; /* linked list of answer RRs */
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struct server_reply_item *authority; /* linked list of authority RRs */
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struct server_reply_item *additional; /* linked list of additional RRs */
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/* Constructed response. Only set once we're ready to send a reply. */
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/* Once this is set, the RR fields are cleared, and no more should be set. */
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char *response;
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size_t response_len;
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/* Caller-visible fields: flags, questions. */
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struct evdns_server_request base;
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};
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struct evdns_base {
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/* An array of n_req_heads circular lists for inflight requests.
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* Each inflight request req is in req_heads[req->trans_id % n_req_heads].
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*/
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struct request **req_heads;
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/* A circular list of requests that we're waiting to send, but haven't
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* sent yet because there are too many requests inflight */
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struct request *req_waiting_head;
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/* A circular list of nameservers. */
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struct nameserver *server_head;
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int n_req_heads;
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struct event_base *event_base;
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/* The number of good nameservers that we have */
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int global_good_nameservers;
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/* inflight requests are contained in the req_head list */
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/* and are actually going out across the network */
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int global_requests_inflight;
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/* requests which aren't inflight are in the waiting list */
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/* and are counted here */
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int global_requests_waiting;
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int global_max_requests_inflight;
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struct timeval global_timeout; /* 5 seconds by default */
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int global_max_reissues; /* a reissue occurs when we get some errors from the server */
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int global_max_retransmits; /* number of times we'll retransmit a request which timed out */
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/* number of timeouts in a row before we consider this server to be down */
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int global_max_nameserver_timeout;
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/* true iff we will use the 0x20 hack to prevent poisoning attacks. */
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int global_randomize_case;
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/* The first time that a nameserver fails, how long do we wait before
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* probing to see if it has returned? */
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struct timeval global_nameserver_probe_initial_timeout;
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/** Port to bind to for outgoing DNS packets. */
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struct sockaddr_storage global_outgoing_address;
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/** ev_socklen_t for global_outgoing_address. 0 if it isn't set. */
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ev_socklen_t global_outgoing_addrlen;
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struct timeval global_getaddrinfo_allow_skew;
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int so_rcvbuf;
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int so_sndbuf;
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int getaddrinfo_ipv4_timeouts;
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int getaddrinfo_ipv6_timeouts;
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int getaddrinfo_ipv4_answered;
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int getaddrinfo_ipv6_answered;
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struct search_state *global_search_state;
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TAILQ_HEAD(hosts_list, hosts_entry) hostsdb;
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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void *lock;
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#endif
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int disable_when_inactive;
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};
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struct hosts_entry {
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TAILQ_ENTRY(hosts_entry) next;
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union {
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struct sockaddr sa;
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struct sockaddr_in sin;
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struct sockaddr_in6 sin6;
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} addr;
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int addrlen;
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char hostname[1];
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};
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static struct evdns_base *current_base = NULL;
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struct evdns_base *
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evdns_get_global_base(void)
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{
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return current_base;
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}
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|
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/* Given a pointer to an evdns_server_request, get the corresponding */
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/* server_request. */
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#define TO_SERVER_REQUEST(base_ptr) \
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((struct server_request*) \
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(((char*)(base_ptr) - evutil_offsetof(struct server_request, base))))
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#define REQ_HEAD(base, id) ((base)->req_heads[id % (base)->n_req_heads])
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static struct nameserver *nameserver_pick(struct evdns_base *base);
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static void evdns_request_insert(struct request *req, struct request **head);
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static void evdns_request_remove(struct request *req, struct request **head);
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static void nameserver_ready_callback(evutil_socket_t fd, short events, void *arg);
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static int evdns_transmit(struct evdns_base *base);
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static int evdns_request_transmit(struct request *req);
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static void nameserver_send_probe(struct nameserver *const ns);
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static void search_request_finished(struct evdns_request *const);
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static int search_try_next(struct evdns_request *const req);
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static struct request *search_request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg);
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static void evdns_requests_pump_waiting_queue(struct evdns_base *base);
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static u16 transaction_id_pick(struct evdns_base *base);
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static struct request *request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *name, int flags, evdns_callback_type callback, void *ptr);
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static void request_submit(struct request *const req);
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|
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static int server_request_free(struct server_request *req);
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static void server_request_free_answers(struct server_request *req);
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static void server_port_free(struct evdns_server_port *port);
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static void server_port_ready_callback(evutil_socket_t fd, short events, void *arg);
|
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static int evdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename);
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static int evdns_base_set_option_impl(struct evdns_base *base,
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const char *option, const char *val, int flags);
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static void evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests);
|
|
static void evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg);
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|
|
|
static int strtoint(const char *const str);
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|
|
|
#ifdef EVENT__DISABLE_THREAD_SUPPORT
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|
#define EVDNS_LOCK(base) EVUTIL_NIL_STMT_
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|
#define EVDNS_UNLOCK(base) EVUTIL_NIL_STMT_
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#define ASSERT_LOCKED(base) EVUTIL_NIL_STMT_
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|
#else
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|
#define EVDNS_LOCK(base) \
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EVLOCK_LOCK((base)->lock, 0)
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|
#define EVDNS_UNLOCK(base) \
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EVLOCK_UNLOCK((base)->lock, 0)
|
|
#define ASSERT_LOCKED(base) \
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EVLOCK_ASSERT_LOCKED((base)->lock)
|
|
#endif
|
|
|
|
static evdns_debug_log_fn_type evdns_log_fn = NULL;
|
|
|
|
void
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|
evdns_set_log_fn(evdns_debug_log_fn_type fn)
|
|
{
|
|
evdns_log_fn = fn;
|
|
}
|
|
|
|
#ifdef __GNUC__
|
|
#define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
|
|
#else
|
|
#define EVDNS_LOG_CHECK
|
|
#endif
|
|
|
|
static void evdns_log_(int severity, const char *fmt, ...) EVDNS_LOG_CHECK;
|
|
static void
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|
evdns_log_(int severity, const char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
va_start(args,fmt);
|
|
if (evdns_log_fn) {
|
|
char buf[512];
|
|
int is_warn = (severity == EVDNS_LOG_WARN);
|
|
evutil_vsnprintf(buf, sizeof(buf), fmt, args);
|
|
evdns_log_fn(is_warn, buf);
|
|
} else {
|
|
event_logv_(severity, NULL, fmt, args);
|
|
}
|
|
va_end(args);
|
|
}
|
|
|
|
#define log evdns_log_
|
|
|
|
/* This walks the list of inflight requests to find the */
|
|
/* one with a matching transaction id. Returns NULL on */
|
|
/* failure */
|
|
static struct request *
|
|
request_find_from_trans_id(struct evdns_base *base, u16 trans_id) {
|
|
struct request *req = REQ_HEAD(base, trans_id);
|
|
struct request *const started_at = req;
|
|
|
|
ASSERT_LOCKED(base);
|
|
|
|
if (req) {
|
|
do {
|
|
if (req->trans_id == trans_id) return req;
|
|
req = req->next;
|
|
} while (req != started_at);
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* a libevent callback function which is called when a nameserver */
|
|
/* has gone down and we want to test if it has came back to life yet */
|
|
static void
|
|
nameserver_prod_callback(evutil_socket_t fd, short events, void *arg) {
|
|
struct nameserver *const ns = (struct nameserver *) arg;
|
|
(void)fd;
|
|
(void)events;
|
|
|
|
EVDNS_LOCK(ns->base);
|
|
nameserver_send_probe(ns);
|
|
EVDNS_UNLOCK(ns->base);
|
|
}
|
|
|
|
/* a libevent callback which is called when a nameserver probe (to see if */
|
|
/* it has come back to life) times out. We increment the count of failed_times */
|
|
/* and wait longer to send the next probe packet. */
|
|
static void
|
|
nameserver_probe_failed(struct nameserver *const ns) {
|
|
struct timeval timeout;
|
|
int i;
|
|
|
|
ASSERT_LOCKED(ns->base);
|
|
(void) evtimer_del(&ns->timeout_event);
|
|
if (ns->state == 1) {
|
|
/* This can happen if the nameserver acts in a way which makes us mark */
|
|
/* it as bad and then starts sending good replies. */
|
|
return;
|
|
}
|
|
|
|
#define MAX_PROBE_TIMEOUT 3600
|
|
#define TIMEOUT_BACKOFF_FACTOR 3
|
|
|
|
memcpy(&timeout, &ns->base->global_nameserver_probe_initial_timeout,
|
|
sizeof(struct timeval));
|
|
for (i=ns->failed_times; i > 0 && timeout.tv_sec < MAX_PROBE_TIMEOUT; --i) {
|
|
timeout.tv_sec *= TIMEOUT_BACKOFF_FACTOR;
|
|
timeout.tv_usec *= TIMEOUT_BACKOFF_FACTOR;
|
|
if (timeout.tv_usec > 1000000) {
|
|
timeout.tv_sec += timeout.tv_usec / 1000000;
|
|
timeout.tv_usec %= 1000000;
|
|
}
|
|
}
|
|
if (timeout.tv_sec > MAX_PROBE_TIMEOUT) {
|
|
timeout.tv_sec = MAX_PROBE_TIMEOUT;
|
|
timeout.tv_usec = 0;
|
|
}
|
|
|
|
ns->failed_times++;
|
|
|
|
if (evtimer_add(&ns->timeout_event, &timeout) < 0) {
|
|
char addrbuf[128];
|
|
log(EVDNS_LOG_WARN,
|
|
"Error from libevent when adding timer event for %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
}
|
|
}
|
|
|
|
static void
|
|
request_swap_ns(struct request *req, struct nameserver *ns) {
|
|
if (ns && req->ns != ns) {
|
|
EVUTIL_ASSERT(req->ns->requests_inflight > 0);
|
|
req->ns->requests_inflight--;
|
|
ns->requests_inflight++;
|
|
|
|
req->ns = ns;
|
|
}
|
|
}
|
|
|
|
/* called when a nameserver has been deemed to have failed. For example, too */
|
|
/* many packets have timed out etc */
|
|
static void
|
|
nameserver_failed(struct nameserver *const ns, const char *msg) {
|
|
struct request *req, *started_at;
|
|
struct evdns_base *base = ns->base;
|
|
int i;
|
|
char addrbuf[128];
|
|
|
|
ASSERT_LOCKED(base);
|
|
/* if this nameserver has already been marked as failed */
|
|
/* then don't do anything */
|
|
if (!ns->state) return;
|
|
|
|
log(EVDNS_LOG_MSG, "Nameserver %s has failed: %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)),
|
|
msg);
|
|
|
|
base->global_good_nameservers--;
|
|
EVUTIL_ASSERT(base->global_good_nameservers >= 0);
|
|
if (base->global_good_nameservers == 0) {
|
|
log(EVDNS_LOG_MSG, "All nameservers have failed");
|
|
}
|
|
|
|
ns->state = 0;
|
|
ns->failed_times = 1;
|
|
|
|
if (evtimer_add(&ns->timeout_event,
|
|
&base->global_nameserver_probe_initial_timeout) < 0) {
|
|
log(EVDNS_LOG_WARN,
|
|
"Error from libevent when adding timer event for %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
/* ???? Do more? */
|
|
}
|
|
|
|
/* walk the list of inflight requests to see if any can be reassigned to */
|
|
/* a different server. Requests in the waiting queue don't have a */
|
|
/* nameserver assigned yet */
|
|
|
|
/* if we don't have *any* good nameservers then there's no point */
|
|
/* trying to reassign requests to one */
|
|
if (!base->global_good_nameservers) return;
|
|
|
|
for (i = 0; i < base->n_req_heads; ++i) {
|
|
req = started_at = base->req_heads[i];
|
|
if (req) {
|
|
do {
|
|
if (req->tx_count == 0 && req->ns == ns) {
|
|
/* still waiting to go out, can be moved */
|
|
/* to another server */
|
|
request_swap_ns(req, nameserver_pick(base));
|
|
}
|
|
req = req->next;
|
|
} while (req != started_at);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
nameserver_up(struct nameserver *const ns)
|
|
{
|
|
char addrbuf[128];
|
|
ASSERT_LOCKED(ns->base);
|
|
if (ns->state) return;
|
|
log(EVDNS_LOG_MSG, "Nameserver %s is back up",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
evtimer_del(&ns->timeout_event);
|
|
if (ns->probe_request) {
|
|
evdns_cancel_request(ns->base, ns->probe_request);
|
|
ns->probe_request = NULL;
|
|
}
|
|
ns->state = 1;
|
|
ns->failed_times = 0;
|
|
ns->timedout = 0;
|
|
ns->base->global_good_nameservers++;
|
|
}
|
|
|
|
static void
|
|
request_trans_id_set(struct request *const req, const u16 trans_id) {
|
|
req->trans_id = trans_id;
|
|
*((u16 *) req->request) = htons(trans_id);
|
|
}
|
|
|
|
/* Called to remove a request from a list and dealloc it. */
|
|
/* head is a pointer to the head of the list it should be */
|
|
/* removed from or NULL if the request isn't in a list. */
|
|
/* when free_handle is one, free the handle as well. */
|
|
static void
|
|
request_finished(struct request *const req, struct request **head, int free_handle) {
|
|
struct evdns_base *base = req->base;
|
|
int was_inflight = (head != &base->req_waiting_head);
|
|
EVDNS_LOCK(base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
|
|
if (head)
|
|
evdns_request_remove(req, head);
|
|
|
|
log(EVDNS_LOG_DEBUG, "Removing timeout for request %p", req);
|
|
if (was_inflight) {
|
|
evtimer_del(&req->timeout_event);
|
|
base->global_requests_inflight--;
|
|
req->ns->requests_inflight--;
|
|
} else {
|
|
base->global_requests_waiting--;
|
|
}
|
|
/* it was initialized during request_new / evtimer_assign */
|
|
event_debug_unassign(&req->timeout_event);
|
|
|
|
if (req->ns &&
|
|
req->ns->requests_inflight == 0 &&
|
|
req->base->disable_when_inactive) {
|
|
event_del(&req->ns->event);
|
|
evtimer_del(&req->ns->timeout_event);
|
|
}
|
|
|
|
if (!req->request_appended) {
|
|
/* need to free the request data on it's own */
|
|
mm_free(req->request);
|
|
} else {
|
|
/* the request data is appended onto the header */
|
|
/* so everything gets free()ed when we: */
|
|
}
|
|
|
|
if (req->handle) {
|
|
EVUTIL_ASSERT(req->handle->current_req == req);
|
|
|
|
if (free_handle) {
|
|
search_request_finished(req->handle);
|
|
req->handle->current_req = NULL;
|
|
if (! req->handle->pending_cb) {
|
|
/* If we're planning to run the callback,
|
|
* don't free the handle until later. */
|
|
mm_free(req->handle);
|
|
}
|
|
req->handle = NULL; /* If we have a bug, let's crash
|
|
* early */
|
|
} else {
|
|
req->handle->current_req = NULL;
|
|
}
|
|
}
|
|
|
|
mm_free(req);
|
|
|
|
evdns_requests_pump_waiting_queue(base);
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
|
|
/* This is called when a server returns a funny error code. */
|
|
/* We try the request again with another server. */
|
|
/* */
|
|
/* return: */
|
|
/* 0 ok */
|
|
/* 1 failed/reissue is pointless */
|
|
static int
|
|
request_reissue(struct request *req) {
|
|
const struct nameserver *const last_ns = req->ns;
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
/* the last nameserver should have been marked as failing */
|
|
/* by the caller of this function, therefore pick will try */
|
|
/* not to return it */
|
|
request_swap_ns(req, nameserver_pick(req->base));
|
|
if (req->ns == last_ns) {
|
|
/* ... but pick did return it */
|
|
/* not a lot of point in trying again with the */
|
|
/* same server */
|
|
return 1;
|
|
}
|
|
|
|
req->reissue_count++;
|
|
req->tx_count = 0;
|
|
req->transmit_me = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* this function looks for space on the inflight queue and promotes */
|
|
/* requests from the waiting queue if it can. */
|
|
/* */
|
|
/* TODO: */
|
|
/* add return code, see at nameserver_pick() and other functions. */
|
|
static void
|
|
evdns_requests_pump_waiting_queue(struct evdns_base *base) {
|
|
ASSERT_LOCKED(base);
|
|
while (base->global_requests_inflight < base->global_max_requests_inflight &&
|
|
base->global_requests_waiting) {
|
|
struct request *req;
|
|
|
|
EVUTIL_ASSERT(base->req_waiting_head);
|
|
req = base->req_waiting_head;
|
|
|
|
req->ns = nameserver_pick(base);
|
|
if (!req->ns)
|
|
return;
|
|
|
|
/* move a request from the waiting queue to the inflight queue */
|
|
req->ns->requests_inflight++;
|
|
|
|
evdns_request_remove(req, &base->req_waiting_head);
|
|
|
|
base->global_requests_waiting--;
|
|
base->global_requests_inflight++;
|
|
|
|
request_trans_id_set(req, transaction_id_pick(base));
|
|
|
|
evdns_request_insert(req, &REQ_HEAD(base, req->trans_id));
|
|
evdns_request_transmit(req);
|
|
evdns_transmit(base);
|
|
}
|
|
}
|
|
|
|
/* TODO(nickm) document */
|
|
struct deferred_reply_callback {
|
|
struct event_callback deferred;
|
|
struct evdns_request *handle;
|
|
u8 request_type;
|
|
u8 have_reply;
|
|
u32 ttl;
|
|
u32 err;
|
|
evdns_callback_type user_callback;
|
|
struct reply reply;
|
|
};
|
|
|
|
static void
|
|
reply_run_callback(struct event_callback *d, void *user_pointer)
|
|
{
|
|
struct deferred_reply_callback *cb =
|
|
EVUTIL_UPCAST(d, struct deferred_reply_callback, deferred);
|
|
|
|
switch (cb->request_type) {
|
|
case TYPE_A:
|
|
if (cb->have_reply)
|
|
cb->user_callback(DNS_ERR_NONE, DNS_IPv4_A,
|
|
cb->reply.data.a.addrcount, cb->ttl,
|
|
cb->reply.data.a.addresses,
|
|
user_pointer);
|
|
else
|
|
cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer);
|
|
break;
|
|
case TYPE_PTR:
|
|
if (cb->have_reply) {
|
|
char *name = cb->reply.data.ptr.name;
|
|
cb->user_callback(DNS_ERR_NONE, DNS_PTR, 1, cb->ttl,
|
|
&name, user_pointer);
|
|
} else {
|
|
cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer);
|
|
}
|
|
break;
|
|
case TYPE_AAAA:
|
|
if (cb->have_reply)
|
|
cb->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
|
|
cb->reply.data.aaaa.addrcount, cb->ttl,
|
|
cb->reply.data.aaaa.addresses,
|
|
user_pointer);
|
|
else
|
|
cb->user_callback(cb->err, 0, 0, cb->ttl, NULL, user_pointer);
|
|
break;
|
|
default:
|
|
EVUTIL_ASSERT(0);
|
|
}
|
|
|
|
if (cb->handle && cb->handle->pending_cb) {
|
|
mm_free(cb->handle);
|
|
}
|
|
|
|
mm_free(cb);
|
|
}
|
|
|
|
static void
|
|
reply_schedule_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply)
|
|
{
|
|
struct deferred_reply_callback *d = mm_calloc(1, sizeof(*d));
|
|
|
|
if (!d) {
|
|
event_warn("%s: Couldn't allocate space for deferred callback.",
|
|
__func__);
|
|
return;
|
|
}
|
|
|
|
ASSERT_LOCKED(req->base);
|
|
|
|
d->request_type = req->request_type;
|
|
d->user_callback = req->user_callback;
|
|
d->ttl = ttl;
|
|
d->err = err;
|
|
if (reply) {
|
|
d->have_reply = 1;
|
|
memcpy(&d->reply, reply, sizeof(struct reply));
|
|
}
|
|
|
|
if (req->handle) {
|
|
req->handle->pending_cb = 1;
|
|
d->handle = req->handle;
|
|
}
|
|
|
|
event_deferred_cb_init_(
|
|
&d->deferred,
|
|
event_get_priority(&req->timeout_event),
|
|
reply_run_callback,
|
|
req->user_pointer);
|
|
event_deferred_cb_schedule_(
|
|
req->base->event_base,
|
|
&d->deferred);
|
|
}
|
|
|
|
|
|
#define _QR_MASK 0x8000U
|
|
#define _OP_MASK 0x7800U
|
|
#define _AA_MASK 0x0400U
|
|
#define _TC_MASK 0x0200U
|
|
#define _RD_MASK 0x0100U
|
|
#define _RA_MASK 0x0080U
|
|
#define _Z_MASK 0x0040U
|
|
#define _AD_MASK 0x0020U
|
|
#define _CD_MASK 0x0010U
|
|
#define _RCODE_MASK 0x000fU
|
|
#define _Z_MASK_DEPRECATED 0x0070U
|
|
|
|
/* this processes a parsed reply packet */
|
|
static void
|
|
reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) {
|
|
int error;
|
|
char addrbuf[128];
|
|
static const int error_codes[] = {
|
|
DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST,
|
|
DNS_ERR_NOTIMPL, DNS_ERR_REFUSED
|
|
};
|
|
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
|
|
if (flags & (_RCODE_MASK | _TC_MASK) || !reply || !reply->have_answer) {
|
|
/* there was an error */
|
|
if (flags & _TC_MASK) {
|
|
error = DNS_ERR_TRUNCATED;
|
|
} else if (flags & _RCODE_MASK) {
|
|
u16 error_code = (flags & _RCODE_MASK) - 1;
|
|
if (error_code > 4) {
|
|
error = DNS_ERR_UNKNOWN;
|
|
} else {
|
|
error = error_codes[error_code];
|
|
}
|
|
} else if (reply && !reply->have_answer) {
|
|
error = DNS_ERR_NODATA;
|
|
} else {
|
|
error = DNS_ERR_UNKNOWN;
|
|
}
|
|
|
|
switch (error) {
|
|
case DNS_ERR_NOTIMPL:
|
|
case DNS_ERR_REFUSED:
|
|
/* we regard these errors as marking a bad nameserver */
|
|
if (req->reissue_count < req->base->global_max_reissues) {
|
|
char msg[64];
|
|
evutil_snprintf(msg, sizeof(msg), "Bad response %d (%s)",
|
|
error, evdns_err_to_string(error));
|
|
nameserver_failed(req->ns, msg);
|
|
if (!request_reissue(req)) return;
|
|
}
|
|
break;
|
|
case DNS_ERR_SERVERFAILED:
|
|
/* rcode 2 (servfailed) sometimes means "we
|
|
* are broken" and sometimes (with some binds)
|
|
* means "that request was very confusing."
|
|
* Treat this as a timeout, not a failure.
|
|
*/
|
|
log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver"
|
|
"at %s; will allow the request to time out.",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&req->ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
/* Call the timeout function */
|
|
evdns_request_timeout_callback(0, 0, req);
|
|
return;
|
|
default:
|
|
/* we got a good reply from the nameserver: it is up. */
|
|
if (req->handle == req->ns->probe_request) {
|
|
/* Avoid double-free */
|
|
req->ns->probe_request = NULL;
|
|
}
|
|
|
|
nameserver_up(req->ns);
|
|
}
|
|
|
|
if (req->handle->search_state &&
|
|
req->request_type != TYPE_PTR) {
|
|
/* if we have a list of domains to search in,
|
|
* try the next one */
|
|
if (!search_try_next(req->handle)) {
|
|
/* a new request was issued so this
|
|
* request is finished and */
|
|
/* the user callback will be made when
|
|
* that request (or a */
|
|
/* child of it) finishes. */
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* all else failed. Pass the failure up */
|
|
reply_schedule_callback(req, ttl, error, NULL);
|
|
request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
|
|
} else {
|
|
/* all ok, tell the user */
|
|
reply_schedule_callback(req, ttl, 0, reply);
|
|
if (req->handle == req->ns->probe_request)
|
|
req->ns->probe_request = NULL; /* Avoid double-free */
|
|
nameserver_up(req->ns);
|
|
request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
|
|
}
|
|
}
|
|
|
|
static int
|
|
name_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) {
|
|
int name_end = -1;
|
|
int j = *idx;
|
|
int ptr_count = 0;
|
|
#define GET32(x) do { if (j + 4 > length) goto err; memcpy(&t32_, packet + j, 4); j += 4; x = ntohl(t32_); } while (0)
|
|
#define GET16(x) do { if (j + 2 > length) goto err; memcpy(&t_, packet + j, 2); j += 2; x = ntohs(t_); } while (0)
|
|
#define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while (0)
|
|
|
|
char *cp = name_out;
|
|
const char *const end = name_out + name_out_len;
|
|
|
|
/* Normally, names are a series of length prefixed strings terminated */
|
|
/* with a length of 0 (the lengths are u8's < 63). */
|
|
/* However, the length can start with a pair of 1 bits and that */
|
|
/* means that the next 14 bits are a pointer within the current */
|
|
/* packet. */
|
|
|
|
for (;;) {
|
|
u8 label_len;
|
|
GET8(label_len);
|
|
if (!label_len) break;
|
|
if (label_len & 0xc0) {
|
|
u8 ptr_low;
|
|
GET8(ptr_low);
|
|
if (name_end < 0) name_end = j;
|
|
j = (((int)label_len & 0x3f) << 8) + ptr_low;
|
|
/* Make sure that the target offset is in-bounds. */
|
|
if (j < 0 || j >= length) return -1;
|
|
/* If we've jumped more times than there are characters in the
|
|
* message, we must have a loop. */
|
|
if (++ptr_count > length) return -1;
|
|
continue;
|
|
}
|
|
if (label_len > 63) return -1;
|
|
if (cp != name_out) {
|
|
if (cp + 1 >= end) return -1;
|
|
*cp++ = '.';
|
|
}
|
|
if (cp + label_len >= end) return -1;
|
|
if (j + label_len > length) return -1;
|
|
memcpy(cp, packet + j, label_len);
|
|
cp += label_len;
|
|
j += label_len;
|
|
}
|
|
if (cp >= end) return -1;
|
|
*cp = '\0';
|
|
if (name_end < 0)
|
|
*idx = j;
|
|
else
|
|
*idx = name_end;
|
|
return 0;
|
|
err:
|
|
return -1;
|
|
}
|
|
|
|
/* parses a raw request from a nameserver */
|
|
static int
|
|
reply_parse(struct evdns_base *base, u8 *packet, int length) {
|
|
int j = 0, k = 0; /* index into packet */
|
|
u16 t_; /* used by the macros */
|
|
u32 t32_; /* used by the macros */
|
|
char tmp_name[256], cmp_name[256]; /* used by the macros */
|
|
int name_matches = 0;
|
|
|
|
u16 trans_id, questions, answers, authority, additional, datalength;
|
|
u16 flags = 0;
|
|
u32 ttl, ttl_r = 0xffffffff;
|
|
struct reply reply;
|
|
struct request *req = NULL;
|
|
unsigned int i;
|
|
|
|
ASSERT_LOCKED(base);
|
|
|
|
GET16(trans_id);
|
|
GET16(flags);
|
|
GET16(questions);
|
|
GET16(answers);
|
|
GET16(authority);
|
|
GET16(additional);
|
|
(void) authority; /* suppress "unused variable" warnings. */
|
|
(void) additional; /* suppress "unused variable" warnings. */
|
|
|
|
req = request_find_from_trans_id(base, trans_id);
|
|
if (!req) return -1;
|
|
EVUTIL_ASSERT(req->base == base);
|
|
|
|
memset(&reply, 0, sizeof(reply));
|
|
|
|
/* If it's not an answer, it doesn't correspond to any request. */
|
|
if (!(flags & _QR_MASK)) return -1; /* must be an answer */
|
|
if ((flags & (_RCODE_MASK|_TC_MASK)) && (flags & (_RCODE_MASK|_TC_MASK)) != DNS_ERR_NOTEXIST) {
|
|
/* there was an error and it's not NXDOMAIN */
|
|
goto err;
|
|
}
|
|
/* if (!answers) return; */ /* must have an answer of some form */
|
|
|
|
/* This macro skips a name in the DNS reply. */
|
|
#define SKIP_NAME \
|
|
do { tmp_name[0] = '\0'; \
|
|
if (name_parse(packet, length, &j, tmp_name, \
|
|
sizeof(tmp_name))<0) \
|
|
goto err; \
|
|
} while (0)
|
|
|
|
reply.type = req->request_type;
|
|
|
|
/* skip over each question in the reply */
|
|
for (i = 0; i < questions; ++i) {
|
|
/* the question looks like
|
|
* <label:name><u16:type><u16:class>
|
|
*/
|
|
tmp_name[0] = '\0';
|
|
cmp_name[0] = '\0';
|
|
k = j;
|
|
if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name)) < 0)
|
|
goto err;
|
|
if (name_parse(req->request, req->request_len, &k,
|
|
cmp_name, sizeof(cmp_name))<0)
|
|
goto err;
|
|
if (!base->global_randomize_case) {
|
|
if (strcmp(tmp_name, cmp_name) == 0)
|
|
name_matches = 1;
|
|
} else {
|
|
if (evutil_ascii_strcasecmp(tmp_name, cmp_name) == 0)
|
|
name_matches = 1;
|
|
}
|
|
|
|
j += 4;
|
|
if (j > length)
|
|
goto err;
|
|
}
|
|
|
|
if (!name_matches)
|
|
goto err;
|
|
|
|
/* now we have the answer section which looks like
|
|
* <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
|
|
*/
|
|
|
|
for (i = 0; i < answers; ++i) {
|
|
u16 type, class;
|
|
|
|
SKIP_NAME;
|
|
GET16(type);
|
|
GET16(class);
|
|
GET32(ttl);
|
|
GET16(datalength);
|
|
|
|
if (type == TYPE_A && class == CLASS_INET) {
|
|
int addrcount, addrtocopy;
|
|
if (req->request_type != TYPE_A) {
|
|
j += datalength; continue;
|
|
}
|
|
if ((datalength & 3) != 0) /* not an even number of As. */
|
|
goto err;
|
|
addrcount = datalength >> 2;
|
|
addrtocopy = MIN(MAX_V4_ADDRS - reply.data.a.addrcount, (unsigned)addrcount);
|
|
|
|
ttl_r = MIN(ttl_r, ttl);
|
|
/* we only bother with the first four addresses. */
|
|
if (j + 4*addrtocopy > length) goto err;
|
|
memcpy(&reply.data.a.addresses[reply.data.a.addrcount],
|
|
packet + j, 4*addrtocopy);
|
|
j += 4*addrtocopy;
|
|
reply.data.a.addrcount += addrtocopy;
|
|
reply.have_answer = 1;
|
|
if (reply.data.a.addrcount == MAX_V4_ADDRS) break;
|
|
} else if (type == TYPE_PTR && class == CLASS_INET) {
|
|
if (req->request_type != TYPE_PTR) {
|
|
j += datalength; continue;
|
|
}
|
|
if (name_parse(packet, length, &j, reply.data.ptr.name,
|
|
sizeof(reply.data.ptr.name))<0)
|
|
goto err;
|
|
ttl_r = MIN(ttl_r, ttl);
|
|
reply.have_answer = 1;
|
|
break;
|
|
} else if (type == TYPE_CNAME) {
|
|
char cname[HOST_NAME_MAX];
|
|
if (!req->put_cname_in_ptr || *req->put_cname_in_ptr) {
|
|
j += datalength; continue;
|
|
}
|
|
if (name_parse(packet, length, &j, cname,
|
|
sizeof(cname))<0)
|
|
goto err;
|
|
*req->put_cname_in_ptr = mm_strdup(cname);
|
|
} else if (type == TYPE_AAAA && class == CLASS_INET) {
|
|
int addrcount, addrtocopy;
|
|
if (req->request_type != TYPE_AAAA) {
|
|
j += datalength; continue;
|
|
}
|
|
if ((datalength & 15) != 0) /* not an even number of AAAAs. */
|
|
goto err;
|
|
addrcount = datalength >> 4; /* each address is 16 bytes long */
|
|
addrtocopy = MIN(MAX_V6_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
|
|
ttl_r = MIN(ttl_r, ttl);
|
|
|
|
/* we only bother with the first four addresses. */
|
|
if (j + 16*addrtocopy > length) goto err;
|
|
memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
|
|
packet + j, 16*addrtocopy);
|
|
reply.data.aaaa.addrcount += addrtocopy;
|
|
j += 16*addrtocopy;
|
|
reply.have_answer = 1;
|
|
if (reply.data.aaaa.addrcount == MAX_V6_ADDRS) break;
|
|
} else {
|
|
/* skip over any other type of resource */
|
|
j += datalength;
|
|
}
|
|
}
|
|
|
|
if (!reply.have_answer) {
|
|
for (i = 0; i < authority; ++i) {
|
|
u16 type, class;
|
|
SKIP_NAME;
|
|
GET16(type);
|
|
GET16(class);
|
|
GET32(ttl);
|
|
GET16(datalength);
|
|
if (type == TYPE_SOA && class == CLASS_INET) {
|
|
u32 serial, refresh, retry, expire, minimum;
|
|
SKIP_NAME;
|
|
SKIP_NAME;
|
|
GET32(serial);
|
|
GET32(refresh);
|
|
GET32(retry);
|
|
GET32(expire);
|
|
GET32(minimum);
|
|
(void)expire;
|
|
(void)retry;
|
|
(void)refresh;
|
|
(void)serial;
|
|
ttl_r = MIN(ttl_r, ttl);
|
|
ttl_r = MIN(ttl_r, minimum);
|
|
} else {
|
|
/* skip over any other type of resource */
|
|
j += datalength;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ttl_r == 0xffffffff)
|
|
ttl_r = 0;
|
|
|
|
reply_handle(req, flags, ttl_r, &reply);
|
|
return 0;
|
|
err:
|
|
if (req)
|
|
reply_handle(req, flags, 0, NULL);
|
|
return -1;
|
|
}
|
|
|
|
/* Parse a raw request (packet,length) sent to a nameserver port (port) from */
|
|
/* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
|
|
/* callback. */
|
|
static int
|
|
request_parse(u8 *packet, int length, struct evdns_server_port *port, struct sockaddr *addr, ev_socklen_t addrlen)
|
|
{
|
|
int j = 0; /* index into packet */
|
|
u16 t_; /* used by the macros */
|
|
char tmp_name[256]; /* used by the macros */
|
|
|
|
int i;
|
|
u16 trans_id, flags, questions, answers, authority, additional;
|
|
struct server_request *server_req = NULL;
|
|
|
|
ASSERT_LOCKED(port);
|
|
|
|
/* Get the header fields */
|
|
GET16(trans_id);
|
|
GET16(flags);
|
|
GET16(questions);
|
|
GET16(answers);
|
|
GET16(authority);
|
|
GET16(additional);
|
|
(void)answers;
|
|
(void)additional;
|
|
(void)authority;
|
|
|
|
if (flags & _QR_MASK) return -1; /* Must not be an answer. */
|
|
flags &= (_RD_MASK|_CD_MASK); /* Only RD and CD get preserved. */
|
|
|
|
server_req = mm_malloc(sizeof(struct server_request));
|
|
if (server_req == NULL) return -1;
|
|
memset(server_req, 0, sizeof(struct server_request));
|
|
|
|
server_req->trans_id = trans_id;
|
|
memcpy(&server_req->addr, addr, addrlen);
|
|
server_req->addrlen = addrlen;
|
|
|
|
server_req->base.flags = flags;
|
|
server_req->base.nquestions = 0;
|
|
server_req->base.questions = mm_calloc(sizeof(struct evdns_server_question *), questions);
|
|
if (server_req->base.questions == NULL)
|
|
goto err;
|
|
|
|
for (i = 0; i < questions; ++i) {
|
|
u16 type, class;
|
|
struct evdns_server_question *q;
|
|
int namelen;
|
|
if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)
|
|
goto err;
|
|
GET16(type);
|
|
GET16(class);
|
|
namelen = (int)strlen(tmp_name);
|
|
q = mm_malloc(sizeof(struct evdns_server_question) + namelen);
|
|
if (!q)
|
|
goto err;
|
|
q->type = type;
|
|
q->dns_question_class = class;
|
|
memcpy(q->name, tmp_name, namelen+1);
|
|
server_req->base.questions[server_req->base.nquestions++] = q;
|
|
}
|
|
|
|
/* Ignore answers, authority, and additional. */
|
|
|
|
server_req->port = port;
|
|
port->refcnt++;
|
|
|
|
/* Only standard queries are supported. */
|
|
if (flags & _OP_MASK) {
|
|
evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL);
|
|
return -1;
|
|
}
|
|
|
|
port->user_callback(&(server_req->base), port->user_data);
|
|
|
|
return 0;
|
|
err:
|
|
if (server_req->base.questions) {
|
|
for (i = 0; i < server_req->base.nquestions; ++i)
|
|
mm_free(server_req->base.questions[i]);
|
|
mm_free(server_req->base.questions);
|
|
}
|
|
mm_free(server_req);
|
|
return -1;
|
|
|
|
#undef SKIP_NAME
|
|
#undef GET32
|
|
#undef GET16
|
|
#undef GET8
|
|
}
|
|
|
|
|
|
void
|
|
evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void))
|
|
{
|
|
}
|
|
|
|
void
|
|
evdns_set_random_bytes_fn(void (*fn)(char *, size_t))
|
|
{
|
|
}
|
|
|
|
/* Try to choose a strong transaction id which isn't already in flight */
|
|
static u16
|
|
transaction_id_pick(struct evdns_base *base) {
|
|
ASSERT_LOCKED(base);
|
|
for (;;) {
|
|
u16 trans_id;
|
|
evutil_secure_rng_get_bytes(&trans_id, sizeof(trans_id));
|
|
|
|
if (trans_id == 0xffff) continue;
|
|
/* now check to see if that id is already inflight */
|
|
if (request_find_from_trans_id(base, trans_id) == NULL)
|
|
return trans_id;
|
|
}
|
|
}
|
|
|
|
/* choose a namesever to use. This function will try to ignore */
|
|
/* nameservers which we think are down and load balance across the rest */
|
|
/* by updating the server_head global each time. */
|
|
static struct nameserver *
|
|
nameserver_pick(struct evdns_base *base) {
|
|
struct nameserver *started_at = base->server_head, *picked;
|
|
ASSERT_LOCKED(base);
|
|
if (!base->server_head) return NULL;
|
|
|
|
/* if we don't have any good nameservers then there's no */
|
|
/* point in trying to find one. */
|
|
if (!base->global_good_nameservers) {
|
|
base->server_head = base->server_head->next;
|
|
return base->server_head;
|
|
}
|
|
|
|
/* remember that nameservers are in a circular list */
|
|
for (;;) {
|
|
if (base->server_head->state) {
|
|
/* we think this server is currently good */
|
|
picked = base->server_head;
|
|
base->server_head = base->server_head->next;
|
|
return picked;
|
|
}
|
|
|
|
base->server_head = base->server_head->next;
|
|
if (base->server_head == started_at) {
|
|
/* all the nameservers seem to be down */
|
|
/* so we just return this one and hope for the */
|
|
/* best */
|
|
EVUTIL_ASSERT(base->global_good_nameservers == 0);
|
|
picked = base->server_head;
|
|
base->server_head = base->server_head->next;
|
|
return picked;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* this is called when a namesever socket is ready for reading */
|
|
static void
|
|
nameserver_read(struct nameserver *ns) {
|
|
struct sockaddr_storage ss;
|
|
ev_socklen_t addrlen = sizeof(ss);
|
|
u8 packet[1500];
|
|
char addrbuf[128];
|
|
ASSERT_LOCKED(ns->base);
|
|
|
|
for (;;) {
|
|
const int r = recvfrom(ns->socket, (void*)packet,
|
|
sizeof(packet), 0,
|
|
(struct sockaddr*)&ss, &addrlen);
|
|
if (r < 0) {
|
|
int err = evutil_socket_geterror(ns->socket);
|
|
if (EVUTIL_ERR_RW_RETRIABLE(err))
|
|
return;
|
|
nameserver_failed(ns,
|
|
evutil_socket_error_to_string(err));
|
|
return;
|
|
}
|
|
if (evutil_sockaddr_cmp((struct sockaddr*)&ss,
|
|
(struct sockaddr*)&ns->address, 0)) {
|
|
log(EVDNS_LOG_WARN, "Address mismatch on received "
|
|
"DNS packet. Apparent source was %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ss,
|
|
addrbuf, sizeof(addrbuf)));
|
|
return;
|
|
}
|
|
|
|
ns->timedout = 0;
|
|
reply_parse(ns->base, packet, r);
|
|
}
|
|
}
|
|
|
|
/* Read a packet from a DNS client on a server port s, parse it, and */
|
|
/* act accordingly. */
|
|
static void
|
|
server_port_read(struct evdns_server_port *s) {
|
|
u8 packet[1500];
|
|
struct sockaddr_storage addr;
|
|
ev_socklen_t addrlen;
|
|
int r;
|
|
ASSERT_LOCKED(s);
|
|
|
|
for (;;) {
|
|
addrlen = sizeof(struct sockaddr_storage);
|
|
r = recvfrom(s->socket, (void*)packet, sizeof(packet), 0,
|
|
(struct sockaddr*) &addr, &addrlen);
|
|
if (r < 0) {
|
|
int err = evutil_socket_geterror(s->socket);
|
|
if (EVUTIL_ERR_RW_RETRIABLE(err))
|
|
return;
|
|
log(EVDNS_LOG_WARN,
|
|
"Error %s (%d) while reading request.",
|
|
evutil_socket_error_to_string(err), err);
|
|
return;
|
|
}
|
|
request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
|
|
}
|
|
}
|
|
|
|
/* Try to write all pending replies on a given DNS server port. */
|
|
static void
|
|
server_port_flush(struct evdns_server_port *port)
|
|
{
|
|
struct server_request *req = port->pending_replies;
|
|
ASSERT_LOCKED(port);
|
|
while (req) {
|
|
int r = sendto(port->socket, req->response, (int)req->response_len, 0,
|
|
(struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen);
|
|
if (r < 0) {
|
|
int err = evutil_socket_geterror(port->socket);
|
|
if (EVUTIL_ERR_RW_RETRIABLE(err))
|
|
return;
|
|
log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", evutil_socket_error_to_string(err), err);
|
|
}
|
|
if (server_request_free(req)) {
|
|
/* we released the last reference to req->port. */
|
|
return;
|
|
} else {
|
|
EVUTIL_ASSERT(req != port->pending_replies);
|
|
req = port->pending_replies;
|
|
}
|
|
}
|
|
|
|
/* We have no more pending requests; stop listening for 'writeable' events. */
|
|
(void) event_del(&port->event);
|
|
event_assign(&port->event, port->event_base,
|
|
port->socket, EV_READ | EV_PERSIST,
|
|
server_port_ready_callback, port);
|
|
|
|
if (event_add(&port->event, NULL) < 0) {
|
|
log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server.");
|
|
/* ???? Do more? */
|
|
}
|
|
}
|
|
|
|
/* set if we are waiting for the ability to write to this server. */
|
|
/* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
|
|
/* we stop these events. */
|
|
static void
|
|
nameserver_write_waiting(struct nameserver *ns, char waiting) {
|
|
ASSERT_LOCKED(ns->base);
|
|
if (ns->write_waiting == waiting) return;
|
|
|
|
ns->write_waiting = waiting;
|
|
(void) event_del(&ns->event);
|
|
event_assign(&ns->event, ns->base->event_base,
|
|
ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST,
|
|
nameserver_ready_callback, ns);
|
|
if (event_add(&ns->event, NULL) < 0) {
|
|
char addrbuf[128];
|
|
log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
/* ???? Do more? */
|
|
}
|
|
}
|
|
|
|
/* a callback function. Called by libevent when the kernel says that */
|
|
/* a nameserver socket is ready for writing or reading */
|
|
static void
|
|
nameserver_ready_callback(evutil_socket_t fd, short events, void *arg) {
|
|
struct nameserver *ns = (struct nameserver *) arg;
|
|
(void)fd;
|
|
|
|
EVDNS_LOCK(ns->base);
|
|
if (events & EV_WRITE) {
|
|
ns->choked = 0;
|
|
if (!evdns_transmit(ns->base)) {
|
|
nameserver_write_waiting(ns, 0);
|
|
}
|
|
}
|
|
if (events & EV_READ) {
|
|
nameserver_read(ns);
|
|
}
|
|
EVDNS_UNLOCK(ns->base);
|
|
}
|
|
|
|
/* a callback function. Called by libevent when the kernel says that */
|
|
/* a server socket is ready for writing or reading. */
|
|
static void
|
|
server_port_ready_callback(evutil_socket_t fd, short events, void *arg) {
|
|
struct evdns_server_port *port = (struct evdns_server_port *) arg;
|
|
(void) fd;
|
|
|
|
EVDNS_LOCK(port);
|
|
if (events & EV_WRITE) {
|
|
port->choked = 0;
|
|
server_port_flush(port);
|
|
}
|
|
if (events & EV_READ) {
|
|
server_port_read(port);
|
|
}
|
|
EVDNS_UNLOCK(port);
|
|
}
|
|
|
|
/* This is an inefficient representation; only use it via the dnslabel_table_*
|
|
* functions, so that is can be safely replaced with something smarter later. */
|
|
#define MAX_LABELS 128
|
|
/* Structures used to implement name compression */
|
|
struct dnslabel_entry { char *v; off_t pos; };
|
|
struct dnslabel_table {
|
|
int n_labels; /* number of current entries */
|
|
/* map from name to position in message */
|
|
struct dnslabel_entry labels[MAX_LABELS];
|
|
};
|
|
|
|
/* Initialize dnslabel_table. */
|
|
static void
|
|
dnslabel_table_init(struct dnslabel_table *table)
|
|
{
|
|
table->n_labels = 0;
|
|
}
|
|
|
|
/* Free all storage held by table, but not the table itself. */
|
|
static void
|
|
dnslabel_clear(struct dnslabel_table *table)
|
|
{
|
|
int i;
|
|
for (i = 0; i < table->n_labels; ++i)
|
|
mm_free(table->labels[i].v);
|
|
table->n_labels = 0;
|
|
}
|
|
|
|
/* return the position of the label in the current message, or -1 if the label */
|
|
/* hasn't been used yet. */
|
|
static int
|
|
dnslabel_table_get_pos(const struct dnslabel_table *table, const char *label)
|
|
{
|
|
int i;
|
|
for (i = 0; i < table->n_labels; ++i) {
|
|
if (!strcmp(label, table->labels[i].v))
|
|
return table->labels[i].pos;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/* remember that we've used the label at position pos */
|
|
static int
|
|
dnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos)
|
|
{
|
|
char *v;
|
|
int p;
|
|
if (table->n_labels == MAX_LABELS)
|
|
return (-1);
|
|
v = mm_strdup(label);
|
|
if (v == NULL)
|
|
return (-1);
|
|
p = table->n_labels++;
|
|
table->labels[p].v = v;
|
|
table->labels[p].pos = pos;
|
|
|
|
return (0);
|
|
}
|
|
|
|
/* Converts a string to a length-prefixed set of DNS labels, starting */
|
|
/* at buf[j]. name and buf must not overlap. name_len should be the length */
|
|
/* of name. table is optional, and is used for compression. */
|
|
/* */
|
|
/* Input: abc.def */
|
|
/* Output: <3>abc<3>def<0> */
|
|
/* */
|
|
/* Returns the first index after the encoded name, or negative on error. */
|
|
/* -1 label was > 63 bytes */
|
|
/* -2 name too long to fit in buffer. */
|
|
/* */
|
|
static off_t
|
|
dnsname_to_labels(u8 *const buf, size_t buf_len, off_t j,
|
|
const char *name, const size_t name_len,
|
|
struct dnslabel_table *table) {
|
|
const char *end = name + name_len;
|
|
int ref = 0;
|
|
u16 t_;
|
|
|
|
#define APPEND16(x) do { \
|
|
if (j + 2 > (off_t)buf_len) \
|
|
goto overflow; \
|
|
t_ = htons(x); \
|
|
memcpy(buf + j, &t_, 2); \
|
|
j += 2; \
|
|
} while (0)
|
|
#define APPEND32(x) do { \
|
|
if (j + 4 > (off_t)buf_len) \
|
|
goto overflow; \
|
|
t32_ = htonl(x); \
|
|
memcpy(buf + j, &t32_, 4); \
|
|
j += 4; \
|
|
} while (0)
|
|
|
|
if (name_len > 255) return -2;
|
|
|
|
for (;;) {
|
|
const char *const start = name;
|
|
if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) {
|
|
APPEND16(ref | 0xc000);
|
|
return j;
|
|
}
|
|
name = strchr(name, '.');
|
|
if (!name) {
|
|
const size_t label_len = end - start;
|
|
if (label_len > 63) return -1;
|
|
if ((size_t)(j+label_len+1) > buf_len) return -2;
|
|
if (table) dnslabel_table_add(table, start, j);
|
|
buf[j++] = (ev_uint8_t)label_len;
|
|
|
|
memcpy(buf + j, start, label_len);
|
|
j += (int) label_len;
|
|
break;
|
|
} else {
|
|
/* append length of the label. */
|
|
const size_t label_len = name - start;
|
|
if (label_len > 63) return -1;
|
|
if ((size_t)(j+label_len+1) > buf_len) return -2;
|
|
if (table) dnslabel_table_add(table, start, j);
|
|
buf[j++] = (ev_uint8_t)label_len;
|
|
|
|
memcpy(buf + j, start, label_len);
|
|
j += (int) label_len;
|
|
/* hop over the '.' */
|
|
name++;
|
|
}
|
|
}
|
|
|
|
/* the labels must be terminated by a 0. */
|
|
/* It's possible that the name ended in a . */
|
|
/* in which case the zero is already there */
|
|
if (!j || buf[j-1]) buf[j++] = 0;
|
|
return j;
|
|
overflow:
|
|
return (-2);
|
|
}
|
|
|
|
/* Finds the length of a dns request for a DNS name of the given */
|
|
/* length. The actual request may be smaller than the value returned */
|
|
/* here */
|
|
static size_t
|
|
evdns_request_len(const size_t name_len) {
|
|
return 96 + /* length of the DNS standard header */
|
|
name_len + 2 +
|
|
4; /* space for the resource type */
|
|
}
|
|
|
|
/* build a dns request packet into buf. buf should be at least as long */
|
|
/* as evdns_request_len told you it should be. */
|
|
/* */
|
|
/* Returns the amount of space used. Negative on error. */
|
|
static int
|
|
evdns_request_data_build(const char *const name, const size_t name_len,
|
|
const u16 trans_id, const u16 type, const u16 class,
|
|
u8 *const buf, size_t buf_len) {
|
|
off_t j = 0; /* current offset into buf */
|
|
u16 t_; /* used by the macros */
|
|
|
|
APPEND16(trans_id);
|
|
APPEND16(0x0100); /* standard query, recusion needed */
|
|
APPEND16(1); /* one question */
|
|
APPEND16(0); /* no answers */
|
|
APPEND16(0); /* no authority */
|
|
APPEND16(0); /* no additional */
|
|
|
|
j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL);
|
|
if (j < 0) {
|
|
return (int)j;
|
|
}
|
|
|
|
APPEND16(type);
|
|
APPEND16(class);
|
|
|
|
return (int)j;
|
|
overflow:
|
|
return (-1);
|
|
}
|
|
|
|
/* exported function */
|
|
struct evdns_server_port *
|
|
evdns_add_server_port_with_base(struct event_base *base, evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data)
|
|
{
|
|
struct evdns_server_port *port;
|
|
if (flags)
|
|
return NULL; /* flags not yet implemented */
|
|
if (!(port = mm_malloc(sizeof(struct evdns_server_port))))
|
|
return NULL;
|
|
memset(port, 0, sizeof(struct evdns_server_port));
|
|
|
|
|
|
port->socket = socket;
|
|
port->refcnt = 1;
|
|
port->choked = 0;
|
|
port->closing = 0;
|
|
port->user_callback = cb;
|
|
port->user_data = user_data;
|
|
port->pending_replies = NULL;
|
|
port->event_base = base;
|
|
|
|
event_assign(&port->event, port->event_base,
|
|
port->socket, EV_READ | EV_PERSIST,
|
|
server_port_ready_callback, port);
|
|
if (event_add(&port->event, NULL) < 0) {
|
|
mm_free(port);
|
|
return NULL;
|
|
}
|
|
EVTHREAD_ALLOC_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
|
|
return port;
|
|
}
|
|
|
|
struct evdns_server_port *
|
|
evdns_add_server_port(evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data)
|
|
{
|
|
return evdns_add_server_port_with_base(NULL, socket, flags, cb, user_data);
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_close_server_port(struct evdns_server_port *port)
|
|
{
|
|
EVDNS_LOCK(port);
|
|
if (--port->refcnt == 0) {
|
|
EVDNS_UNLOCK(port);
|
|
server_port_free(port);
|
|
} else {
|
|
port->closing = 1;
|
|
EVDNS_UNLOCK(port);
|
|
}
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_add_reply(struct evdns_server_request *req_, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data)
|
|
{
|
|
struct server_request *req = TO_SERVER_REQUEST(req_);
|
|
struct server_reply_item **itemp, *item;
|
|
int *countp;
|
|
int result = -1;
|
|
|
|
EVDNS_LOCK(req->port);
|
|
if (req->response) /* have we already answered? */
|
|
goto done;
|
|
|
|
switch (section) {
|
|
case EVDNS_ANSWER_SECTION:
|
|
itemp = &req->answer;
|
|
countp = &req->n_answer;
|
|
break;
|
|
case EVDNS_AUTHORITY_SECTION:
|
|
itemp = &req->authority;
|
|
countp = &req->n_authority;
|
|
break;
|
|
case EVDNS_ADDITIONAL_SECTION:
|
|
itemp = &req->additional;
|
|
countp = &req->n_additional;
|
|
break;
|
|
default:
|
|
goto done;
|
|
}
|
|
while (*itemp) {
|
|
itemp = &((*itemp)->next);
|
|
}
|
|
item = mm_malloc(sizeof(struct server_reply_item));
|
|
if (!item)
|
|
goto done;
|
|
item->next = NULL;
|
|
if (!(item->name = mm_strdup(name))) {
|
|
mm_free(item);
|
|
goto done;
|
|
}
|
|
item->type = type;
|
|
item->dns_question_class = class;
|
|
item->ttl = ttl;
|
|
item->is_name = is_name != 0;
|
|
item->datalen = 0;
|
|
item->data = NULL;
|
|
if (data) {
|
|
if (item->is_name) {
|
|
if (!(item->data = mm_strdup(data))) {
|
|
mm_free(item->name);
|
|
mm_free(item);
|
|
goto done;
|
|
}
|
|
item->datalen = (u16)-1;
|
|
} else {
|
|
if (!(item->data = mm_malloc(datalen))) {
|
|
mm_free(item->name);
|
|
mm_free(item);
|
|
goto done;
|
|
}
|
|
item->datalen = datalen;
|
|
memcpy(item->data, data, datalen);
|
|
}
|
|
}
|
|
|
|
*itemp = item;
|
|
++(*countp);
|
|
result = 0;
|
|
done:
|
|
EVDNS_UNLOCK(req->port);
|
|
return result;
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
|
|
{
|
|
return evdns_server_request_add_reply(
|
|
req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET,
|
|
ttl, n*4, 0, addrs);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
|
|
{
|
|
return evdns_server_request_add_reply(
|
|
req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET,
|
|
ttl, n*16, 0, addrs);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl)
|
|
{
|
|
u32 a;
|
|
char buf[32];
|
|
if (in && inaddr_name)
|
|
return -1;
|
|
else if (!in && !inaddr_name)
|
|
return -1;
|
|
if (in) {
|
|
a = ntohl(in->s_addr);
|
|
evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
|
|
(int)(u8)((a )&0xff),
|
|
(int)(u8)((a>>8 )&0xff),
|
|
(int)(u8)((a>>16)&0xff),
|
|
(int)(u8)((a>>24)&0xff));
|
|
inaddr_name = buf;
|
|
}
|
|
return evdns_server_request_add_reply(
|
|
req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET,
|
|
ttl, -1, 1, hostname);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl)
|
|
{
|
|
return evdns_server_request_add_reply(
|
|
req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET,
|
|
ttl, -1, 1, cname);
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_server_request_set_flags(struct evdns_server_request *exreq, int flags)
|
|
{
|
|
struct server_request *req = TO_SERVER_REQUEST(exreq);
|
|
req->base.flags &= ~(EVDNS_FLAGS_AA|EVDNS_FLAGS_RD);
|
|
req->base.flags |= flags;
|
|
}
|
|
|
|
static int
|
|
evdns_server_request_format_response(struct server_request *req, int err)
|
|
{
|
|
unsigned char buf[1500];
|
|
size_t buf_len = sizeof(buf);
|
|
off_t j = 0, r;
|
|
u16 t_;
|
|
u32 t32_;
|
|
int i;
|
|
u16 flags;
|
|
struct dnslabel_table table;
|
|
|
|
if (err < 0 || err > 15) return -1;
|
|
|
|
/* Set response bit and error code; copy OPCODE and RD fields from
|
|
* question; copy RA and AA if set by caller. */
|
|
flags = req->base.flags;
|
|
flags |= (_QR_MASK | err);
|
|
|
|
dnslabel_table_init(&table);
|
|
APPEND16(req->trans_id);
|
|
APPEND16(flags);
|
|
APPEND16(req->base.nquestions);
|
|
APPEND16(req->n_answer);
|
|
APPEND16(req->n_authority);
|
|
APPEND16(req->n_additional);
|
|
|
|
/* Add questions. */
|
|
for (i=0; i < req->base.nquestions; ++i) {
|
|
const char *s = req->base.questions[i]->name;
|
|
j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table);
|
|
if (j < 0) {
|
|
dnslabel_clear(&table);
|
|
return (int) j;
|
|
}
|
|
APPEND16(req->base.questions[i]->type);
|
|
APPEND16(req->base.questions[i]->dns_question_class);
|
|
}
|
|
|
|
/* Add answer, authority, and additional sections. */
|
|
for (i=0; i<3; ++i) {
|
|
struct server_reply_item *item;
|
|
if (i==0)
|
|
item = req->answer;
|
|
else if (i==1)
|
|
item = req->authority;
|
|
else
|
|
item = req->additional;
|
|
while (item) {
|
|
r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table);
|
|
if (r < 0)
|
|
goto overflow;
|
|
j = r;
|
|
|
|
APPEND16(item->type);
|
|
APPEND16(item->dns_question_class);
|
|
APPEND32(item->ttl);
|
|
if (item->is_name) {
|
|
off_t len_idx = j, name_start;
|
|
j += 2;
|
|
name_start = j;
|
|
r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table);
|
|
if (r < 0)
|
|
goto overflow;
|
|
j = r;
|
|
t_ = htons( (short) (j-name_start) );
|
|
memcpy(buf+len_idx, &t_, 2);
|
|
} else {
|
|
APPEND16(item->datalen);
|
|
if (j+item->datalen > (off_t)buf_len)
|
|
goto overflow;
|
|
memcpy(buf+j, item->data, item->datalen);
|
|
j += item->datalen;
|
|
}
|
|
item = item->next;
|
|
}
|
|
}
|
|
|
|
if (j > 512) {
|
|
overflow:
|
|
j = 512;
|
|
buf[2] |= 0x02; /* set the truncated bit. */
|
|
}
|
|
|
|
req->response_len = j;
|
|
|
|
if (!(req->response = mm_malloc(req->response_len))) {
|
|
server_request_free_answers(req);
|
|
dnslabel_clear(&table);
|
|
return (-1);
|
|
}
|
|
memcpy(req->response, buf, req->response_len);
|
|
server_request_free_answers(req);
|
|
dnslabel_clear(&table);
|
|
return (0);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_respond(struct evdns_server_request *req_, int err)
|
|
{
|
|
struct server_request *req = TO_SERVER_REQUEST(req_);
|
|
struct evdns_server_port *port = req->port;
|
|
int r = -1;
|
|
|
|
EVDNS_LOCK(port);
|
|
if (!req->response) {
|
|
if ((r = evdns_server_request_format_response(req, err))<0)
|
|
goto done;
|
|
}
|
|
|
|
r = sendto(port->socket, req->response, (int)req->response_len, 0,
|
|
(struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen);
|
|
if (r<0) {
|
|
int sock_err = evutil_socket_geterror(port->socket);
|
|
if (EVUTIL_ERR_RW_RETRIABLE(sock_err))
|
|
goto done;
|
|
|
|
if (port->pending_replies) {
|
|
req->prev_pending = port->pending_replies->prev_pending;
|
|
req->next_pending = port->pending_replies;
|
|
req->prev_pending->next_pending =
|
|
req->next_pending->prev_pending = req;
|
|
} else {
|
|
req->prev_pending = req->next_pending = req;
|
|
port->pending_replies = req;
|
|
port->choked = 1;
|
|
|
|
(void) event_del(&port->event);
|
|
event_assign(&port->event, port->event_base, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port);
|
|
|
|
if (event_add(&port->event, NULL) < 0) {
|
|
log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server");
|
|
}
|
|
|
|
}
|
|
|
|
r = 1;
|
|
goto done;
|
|
}
|
|
if (server_request_free(req)) {
|
|
r = 0;
|
|
goto done;
|
|
}
|
|
|
|
if (port->pending_replies)
|
|
server_port_flush(port);
|
|
|
|
r = 0;
|
|
done:
|
|
EVDNS_UNLOCK(port);
|
|
return r;
|
|
}
|
|
|
|
/* Free all storage held by RRs in req. */
|
|
static void
|
|
server_request_free_answers(struct server_request *req)
|
|
{
|
|
struct server_reply_item *victim, *next, **list;
|
|
int i;
|
|
for (i = 0; i < 3; ++i) {
|
|
if (i==0)
|
|
list = &req->answer;
|
|
else if (i==1)
|
|
list = &req->authority;
|
|
else
|
|
list = &req->additional;
|
|
|
|
victim = *list;
|
|
while (victim) {
|
|
next = victim->next;
|
|
mm_free(victim->name);
|
|
if (victim->data)
|
|
mm_free(victim->data);
|
|
mm_free(victim);
|
|
victim = next;
|
|
}
|
|
*list = NULL;
|
|
}
|
|
}
|
|
|
|
/* Free all storage held by req, and remove links to it. */
|
|
/* return true iff we just wound up freeing the server_port. */
|
|
static int
|
|
server_request_free(struct server_request *req)
|
|
{
|
|
int i, rc=1, lock=0;
|
|
if (req->base.questions) {
|
|
for (i = 0; i < req->base.nquestions; ++i)
|
|
mm_free(req->base.questions[i]);
|
|
mm_free(req->base.questions);
|
|
}
|
|
|
|
if (req->port) {
|
|
EVDNS_LOCK(req->port);
|
|
lock=1;
|
|
if (req->port->pending_replies == req) {
|
|
if (req->next_pending && req->next_pending != req)
|
|
req->port->pending_replies = req->next_pending;
|
|
else
|
|
req->port->pending_replies = NULL;
|
|
}
|
|
rc = --req->port->refcnt;
|
|
}
|
|
|
|
if (req->response) {
|
|
mm_free(req->response);
|
|
}
|
|
|
|
server_request_free_answers(req);
|
|
|
|
if (req->next_pending && req->next_pending != req) {
|
|
req->next_pending->prev_pending = req->prev_pending;
|
|
req->prev_pending->next_pending = req->next_pending;
|
|
}
|
|
|
|
if (rc == 0) {
|
|
EVDNS_UNLOCK(req->port); /* ????? nickm */
|
|
server_port_free(req->port);
|
|
mm_free(req);
|
|
return (1);
|
|
}
|
|
if (lock)
|
|
EVDNS_UNLOCK(req->port);
|
|
mm_free(req);
|
|
return (0);
|
|
}
|
|
|
|
/* Free all storage held by an evdns_server_port. Only called when */
|
|
static void
|
|
server_port_free(struct evdns_server_port *port)
|
|
{
|
|
EVUTIL_ASSERT(port);
|
|
EVUTIL_ASSERT(!port->refcnt);
|
|
EVUTIL_ASSERT(!port->pending_replies);
|
|
if (port->socket > 0) {
|
|
evutil_closesocket(port->socket);
|
|
port->socket = -1;
|
|
}
|
|
(void) event_del(&port->event);
|
|
event_debug_unassign(&port->event);
|
|
EVTHREAD_FREE_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
|
|
mm_free(port);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_drop(struct evdns_server_request *req_)
|
|
{
|
|
struct server_request *req = TO_SERVER_REQUEST(req_);
|
|
server_request_free(req);
|
|
return 0;
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_server_request_get_requesting_addr(struct evdns_server_request *req_, struct sockaddr *sa, int addr_len)
|
|
{
|
|
struct server_request *req = TO_SERVER_REQUEST(req_);
|
|
if (addr_len < (int)req->addrlen)
|
|
return -1;
|
|
memcpy(sa, &(req->addr), req->addrlen);
|
|
return req->addrlen;
|
|
}
|
|
|
|
#undef APPEND16
|
|
#undef APPEND32
|
|
|
|
/* this is a libevent callback function which is called when a request */
|
|
/* has timed out. */
|
|
static void
|
|
evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg) {
|
|
struct request *const req = (struct request *) arg;
|
|
struct evdns_base *base = req->base;
|
|
|
|
(void) fd;
|
|
(void) events;
|
|
|
|
log(EVDNS_LOG_DEBUG, "Request %p timed out", arg);
|
|
EVDNS_LOCK(base);
|
|
|
|
if (req->tx_count >= req->base->global_max_retransmits) {
|
|
struct nameserver *ns = req->ns;
|
|
/* this request has failed */
|
|
log(EVDNS_LOG_DEBUG, "Giving up on request %p; tx_count==%d",
|
|
arg, req->tx_count);
|
|
reply_schedule_callback(req, 0, DNS_ERR_TIMEOUT, NULL);
|
|
|
|
request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
|
|
nameserver_failed(ns, "request timed out.");
|
|
} else {
|
|
/* retransmit it */
|
|
log(EVDNS_LOG_DEBUG, "Retransmitting request %p; tx_count==%d",
|
|
arg, req->tx_count);
|
|
(void) evtimer_del(&req->timeout_event);
|
|
request_swap_ns(req, nameserver_pick(base));
|
|
evdns_request_transmit(req);
|
|
|
|
req->ns->timedout++;
|
|
if (req->ns->timedout > req->base->global_max_nameserver_timeout) {
|
|
req->ns->timedout = 0;
|
|
nameserver_failed(req->ns, "request timed out.");
|
|
}
|
|
}
|
|
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
|
|
/* try to send a request to a given server. */
|
|
/* */
|
|
/* return: */
|
|
/* 0 ok */
|
|
/* 1 temporary failure */
|
|
/* 2 other failure */
|
|
static int
|
|
evdns_request_transmit_to(struct request *req, struct nameserver *server) {
|
|
int r;
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
|
|
if (server->requests_inflight == 1 &&
|
|
req->base->disable_when_inactive &&
|
|
event_add(&server->event, NULL) < 0) {
|
|
return 1;
|
|
}
|
|
|
|
r = sendto(server->socket, (void*)req->request, req->request_len, 0,
|
|
(struct sockaddr *)&server->address, server->addrlen);
|
|
if (r < 0) {
|
|
int err = evutil_socket_geterror(server->socket);
|
|
if (EVUTIL_ERR_RW_RETRIABLE(err))
|
|
return 1;
|
|
nameserver_failed(req->ns, evutil_socket_error_to_string(err));
|
|
return 2;
|
|
} else if (r != (int)req->request_len) {
|
|
return 1; /* short write */
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* try to send a request, updating the fields of the request */
|
|
/* as needed */
|
|
/* */
|
|
/* return: */
|
|
/* 0 ok */
|
|
/* 1 failed */
|
|
static int
|
|
evdns_request_transmit(struct request *req) {
|
|
int retcode = 0, r;
|
|
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
/* if we fail to send this packet then this flag marks it */
|
|
/* for evdns_transmit */
|
|
req->transmit_me = 1;
|
|
EVUTIL_ASSERT(req->trans_id != 0xffff);
|
|
|
|
if (!req->ns)
|
|
{
|
|
/* unable to transmit request if no nameservers */
|
|
return 1;
|
|
}
|
|
|
|
if (req->ns->choked) {
|
|
/* don't bother trying to write to a socket */
|
|
/* which we have had EAGAIN from */
|
|
return 1;
|
|
}
|
|
|
|
r = evdns_request_transmit_to(req, req->ns);
|
|
switch (r) {
|
|
case 1:
|
|
/* temp failure */
|
|
req->ns->choked = 1;
|
|
nameserver_write_waiting(req->ns, 1);
|
|
return 1;
|
|
case 2:
|
|
/* failed to transmit the request entirely. we can fallthrough since
|
|
* we'll set a timeout, which will time out, and make us retransmit the
|
|
* request anyway. */
|
|
retcode = 1;
|
|
EVUTIL_FALLTHROUGH;
|
|
default:
|
|
/* all ok */
|
|
log(EVDNS_LOG_DEBUG,
|
|
"Setting timeout for request %p, sent to nameserver %p", req, req->ns);
|
|
if (evtimer_add(&req->timeout_event, &req->base->global_timeout) < 0) {
|
|
log(EVDNS_LOG_WARN,
|
|
"Error from libevent when adding timer for request %p",
|
|
req);
|
|
/* ???? Do more? */
|
|
}
|
|
req->tx_count++;
|
|
req->transmit_me = 0;
|
|
return retcode;
|
|
}
|
|
}
|
|
|
|
static void
|
|
nameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) {
|
|
struct nameserver *const ns = (struct nameserver *) arg;
|
|
(void) type;
|
|
(void) count;
|
|
(void) ttl;
|
|
(void) addresses;
|
|
|
|
if (result == DNS_ERR_CANCEL) {
|
|
/* We canceled this request because the nameserver came up
|
|
* for some other reason. Do not change our opinion about
|
|
* the nameserver. */
|
|
return;
|
|
}
|
|
|
|
EVDNS_LOCK(ns->base);
|
|
ns->probe_request = NULL;
|
|
if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) {
|
|
/* this is a good reply */
|
|
nameserver_up(ns);
|
|
} else {
|
|
nameserver_probe_failed(ns);
|
|
}
|
|
EVDNS_UNLOCK(ns->base);
|
|
}
|
|
|
|
static void
|
|
nameserver_send_probe(struct nameserver *const ns) {
|
|
struct evdns_request *handle;
|
|
struct request *req;
|
|
char addrbuf[128];
|
|
/* here we need to send a probe to a given nameserver */
|
|
/* in the hope that it is up now. */
|
|
|
|
ASSERT_LOCKED(ns->base);
|
|
log(EVDNS_LOG_DEBUG, "Sending probe to %s",
|
|
evutil_format_sockaddr_port_(
|
|
(struct sockaddr *)&ns->address,
|
|
addrbuf, sizeof(addrbuf)));
|
|
handle = mm_calloc(1, sizeof(*handle));
|
|
if (!handle) return;
|
|
req = request_new(ns->base, handle, TYPE_A, "google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns);
|
|
if (!req) {
|
|
mm_free(handle);
|
|
return;
|
|
}
|
|
ns->probe_request = handle;
|
|
/* we force this into the inflight queue no matter what */
|
|
request_trans_id_set(req, transaction_id_pick(ns->base));
|
|
req->ns = ns;
|
|
request_submit(req);
|
|
}
|
|
|
|
/* returns: */
|
|
/* 0 didn't try to transmit anything */
|
|
/* 1 tried to transmit something */
|
|
static int
|
|
evdns_transmit(struct evdns_base *base) {
|
|
char did_try_to_transmit = 0;
|
|
int i;
|
|
|
|
ASSERT_LOCKED(base);
|
|
for (i = 0; i < base->n_req_heads; ++i) {
|
|
if (base->req_heads[i]) {
|
|
struct request *const started_at = base->req_heads[i], *req = started_at;
|
|
/* first transmit all the requests which are currently waiting */
|
|
do {
|
|
if (req->transmit_me) {
|
|
did_try_to_transmit = 1;
|
|
evdns_request_transmit(req);
|
|
}
|
|
|
|
req = req->next;
|
|
} while (req != started_at);
|
|
}
|
|
}
|
|
|
|
return did_try_to_transmit;
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_count_nameservers(struct evdns_base *base)
|
|
{
|
|
const struct nameserver *server;
|
|
int n = 0;
|
|
|
|
EVDNS_LOCK(base);
|
|
server = base->server_head;
|
|
if (!server)
|
|
goto done;
|
|
do {
|
|
++n;
|
|
server = server->next;
|
|
} while (server != base->server_head);
|
|
done:
|
|
EVDNS_UNLOCK(base);
|
|
return n;
|
|
}
|
|
|
|
int
|
|
evdns_count_nameservers(void)
|
|
{
|
|
return evdns_base_count_nameservers(current_base);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_clear_nameservers_and_suspend(struct evdns_base *base)
|
|
{
|
|
struct nameserver *server, *started_at;
|
|
int i;
|
|
|
|
EVDNS_LOCK(base);
|
|
server = base->server_head;
|
|
started_at = base->server_head;
|
|
if (!server) {
|
|
EVDNS_UNLOCK(base);
|
|
return 0;
|
|
}
|
|
while (1) {
|
|
struct nameserver *next = server->next;
|
|
(void) event_del(&server->event);
|
|
if (evtimer_initialized(&server->timeout_event))
|
|
(void) evtimer_del(&server->timeout_event);
|
|
if (server->probe_request) {
|
|
evdns_cancel_request(server->base, server->probe_request);
|
|
server->probe_request = NULL;
|
|
}
|
|
if (server->socket >= 0)
|
|
evutil_closesocket(server->socket);
|
|
mm_free(server);
|
|
if (next == started_at)
|
|
break;
|
|
server = next;
|
|
}
|
|
base->server_head = NULL;
|
|
base->global_good_nameservers = 0;
|
|
|
|
for (i = 0; i < base->n_req_heads; ++i) {
|
|
struct request *req, *req_started_at;
|
|
req = req_started_at = base->req_heads[i];
|
|
while (req) {
|
|
struct request *next = req->next;
|
|
req->tx_count = req->reissue_count = 0;
|
|
req->ns = NULL;
|
|
/* ???? What to do about searches? */
|
|
(void) evtimer_del(&req->timeout_event);
|
|
req->trans_id = 0;
|
|
req->transmit_me = 0;
|
|
|
|
base->global_requests_waiting++;
|
|
evdns_request_insert(req, &base->req_waiting_head);
|
|
/* We want to insert these suspended elements at the front of
|
|
* the waiting queue, since they were pending before any of
|
|
* the waiting entries were added. This is a circular list,
|
|
* so we can just shift the start back by one.*/
|
|
base->req_waiting_head = base->req_waiting_head->prev;
|
|
|
|
if (next == req_started_at)
|
|
break;
|
|
req = next;
|
|
}
|
|
base->req_heads[i] = NULL;
|
|
}
|
|
|
|
base->global_requests_inflight = 0;
|
|
|
|
EVDNS_UNLOCK(base);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
evdns_clear_nameservers_and_suspend(void)
|
|
{
|
|
return evdns_base_clear_nameservers_and_suspend(current_base);
|
|
}
|
|
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_resume(struct evdns_base *base)
|
|
{
|
|
EVDNS_LOCK(base);
|
|
evdns_requests_pump_waiting_queue(base);
|
|
EVDNS_UNLOCK(base);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
evdns_resume(void)
|
|
{
|
|
return evdns_base_resume(current_base);
|
|
}
|
|
|
|
static int
|
|
evdns_nameserver_add_impl_(struct evdns_base *base, const struct sockaddr *address, int addrlen) {
|
|
/* first check to see if we already have this nameserver */
|
|
|
|
const struct nameserver *server = base->server_head, *const started_at = base->server_head;
|
|
struct nameserver *ns;
|
|
int err = 0;
|
|
char addrbuf[128];
|
|
|
|
ASSERT_LOCKED(base);
|
|
if (server) {
|
|
do {
|
|
if (!evutil_sockaddr_cmp((struct sockaddr*)&server->address, address, 1)) return 3;
|
|
server = server->next;
|
|
} while (server != started_at);
|
|
}
|
|
if (addrlen > (int)sizeof(ns->address)) {
|
|
log(EVDNS_LOG_DEBUG, "Addrlen %d too long.", (int)addrlen);
|
|
return 2;
|
|
}
|
|
|
|
ns = (struct nameserver *) mm_malloc(sizeof(struct nameserver));
|
|
if (!ns) return -1;
|
|
|
|
memset(ns, 0, sizeof(struct nameserver));
|
|
ns->base = base;
|
|
|
|
evtimer_assign(&ns->timeout_event, ns->base->event_base, nameserver_prod_callback, ns);
|
|
|
|
ns->socket = evutil_socket_(address->sa_family,
|
|
SOCK_DGRAM|EVUTIL_SOCK_NONBLOCK|EVUTIL_SOCK_CLOEXEC, 0);
|
|
if (ns->socket < 0) { err = 1; goto out1; }
|
|
|
|
if (base->global_outgoing_addrlen &&
|
|
!evutil_sockaddr_is_loopback_(address)) {
|
|
if (bind(ns->socket,
|
|
(struct sockaddr*)&base->global_outgoing_address,
|
|
base->global_outgoing_addrlen) < 0) {
|
|
log(EVDNS_LOG_WARN,"Couldn't bind to outgoing address");
|
|
err = 2;
|
|
goto out2;
|
|
}
|
|
}
|
|
|
|
if (base->so_rcvbuf) {
|
|
if (setsockopt(ns->socket, SOL_SOCKET, SO_RCVBUF,
|
|
(void *)&base->so_rcvbuf, sizeof(base->so_rcvbuf))) {
|
|
log(EVDNS_LOG_WARN, "Couldn't set SO_RCVBUF to %i", base->so_rcvbuf);
|
|
err = -SO_RCVBUF;
|
|
goto out2;
|
|
}
|
|
}
|
|
if (base->so_sndbuf) {
|
|
if (setsockopt(ns->socket, SOL_SOCKET, SO_SNDBUF,
|
|
(void *)&base->so_sndbuf, sizeof(base->so_sndbuf))) {
|
|
log(EVDNS_LOG_WARN, "Couldn't set SO_SNDBUF to %i", base->so_sndbuf);
|
|
err = -SO_SNDBUF;
|
|
goto out2;
|
|
}
|
|
}
|
|
|
|
memcpy(&ns->address, address, addrlen);
|
|
ns->addrlen = addrlen;
|
|
ns->state = 1;
|
|
event_assign(&ns->event, ns->base->event_base, ns->socket,
|
|
EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
|
|
if (!base->disable_when_inactive && event_add(&ns->event, NULL) < 0) {
|
|
err = 2;
|
|
goto out2;
|
|
}
|
|
|
|
log(EVDNS_LOG_DEBUG, "Added nameserver %s as %p",
|
|
evutil_format_sockaddr_port_(address, addrbuf, sizeof(addrbuf)), ns);
|
|
|
|
/* insert this nameserver into the list of them */
|
|
if (!base->server_head) {
|
|
ns->next = ns->prev = ns;
|
|
base->server_head = ns;
|
|
} else {
|
|
ns->next = base->server_head->next;
|
|
ns->prev = base->server_head;
|
|
base->server_head->next = ns;
|
|
ns->next->prev = ns;
|
|
}
|
|
|
|
base->global_good_nameservers++;
|
|
|
|
return 0;
|
|
|
|
out2:
|
|
evutil_closesocket(ns->socket);
|
|
out1:
|
|
event_debug_unassign(&ns->event);
|
|
mm_free(ns);
|
|
log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d",
|
|
evutil_format_sockaddr_port_(address, addrbuf, sizeof(addrbuf)), err);
|
|
return err;
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_nameserver_add(struct evdns_base *base, unsigned long int address)
|
|
{
|
|
struct sockaddr_in sin;
|
|
int res;
|
|
memset(&sin, 0, sizeof(sin));
|
|
sin.sin_addr.s_addr = address;
|
|
sin.sin_port = htons(53);
|
|
sin.sin_family = AF_INET;
|
|
EVDNS_LOCK(base);
|
|
res = evdns_nameserver_add_impl_(base, (struct sockaddr*)&sin, sizeof(sin));
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
int
|
|
evdns_nameserver_add(unsigned long int address) {
|
|
if (!current_base)
|
|
current_base = evdns_base_new(NULL, 0);
|
|
return evdns_base_nameserver_add(current_base, address);
|
|
}
|
|
|
|
static void
|
|
sockaddr_setport(struct sockaddr *sa, ev_uint16_t port)
|
|
{
|
|
if (sa->sa_family == AF_INET) {
|
|
((struct sockaddr_in *)sa)->sin_port = htons(port);
|
|
} else if (sa->sa_family == AF_INET6) {
|
|
((struct sockaddr_in6 *)sa)->sin6_port = htons(port);
|
|
}
|
|
}
|
|
|
|
static ev_uint16_t
|
|
sockaddr_getport(struct sockaddr *sa)
|
|
{
|
|
if (sa->sa_family == AF_INET) {
|
|
return ntohs(((struct sockaddr_in *)sa)->sin_port);
|
|
} else if (sa->sa_family == AF_INET6) {
|
|
return ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_nameserver_ip_add(struct evdns_base *base, const char *ip_as_string) {
|
|
struct sockaddr_storage ss;
|
|
struct sockaddr *sa;
|
|
int len = sizeof(ss);
|
|
int res;
|
|
if (evutil_parse_sockaddr_port(ip_as_string, (struct sockaddr *)&ss,
|
|
&len)) {
|
|
log(EVDNS_LOG_WARN, "Unable to parse nameserver address %s",
|
|
ip_as_string);
|
|
return 4;
|
|
}
|
|
sa = (struct sockaddr *) &ss;
|
|
if (sockaddr_getport(sa) == 0)
|
|
sockaddr_setport(sa, 53);
|
|
|
|
EVDNS_LOCK(base);
|
|
res = evdns_nameserver_add_impl_(base, sa, len);
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
int
|
|
evdns_nameserver_ip_add(const char *ip_as_string) {
|
|
if (!current_base)
|
|
current_base = evdns_base_new(NULL, 0);
|
|
return evdns_base_nameserver_ip_add(current_base, ip_as_string);
|
|
}
|
|
|
|
int
|
|
evdns_base_nameserver_sockaddr_add(struct evdns_base *base,
|
|
const struct sockaddr *sa, ev_socklen_t len, unsigned flags)
|
|
{
|
|
int res;
|
|
EVUTIL_ASSERT(base);
|
|
EVDNS_LOCK(base);
|
|
res = evdns_nameserver_add_impl_(base, sa, len);
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
int
|
|
evdns_base_get_nameserver_addr(struct evdns_base *base, int idx,
|
|
struct sockaddr *sa, ev_socklen_t len)
|
|
{
|
|
int result = -1;
|
|
int i;
|
|
struct nameserver *server;
|
|
EVDNS_LOCK(base);
|
|
server = base->server_head;
|
|
for (i = 0; i < idx && server; ++i, server = server->next) {
|
|
if (server->next == base->server_head)
|
|
goto done;
|
|
}
|
|
if (! server)
|
|
goto done;
|
|
|
|
if (server->addrlen > len) {
|
|
result = (int) server->addrlen;
|
|
goto done;
|
|
}
|
|
|
|
memcpy(sa, &server->address, server->addrlen);
|
|
result = (int) server->addrlen;
|
|
done:
|
|
EVDNS_UNLOCK(base);
|
|
return result;
|
|
}
|
|
|
|
/* remove from the queue */
|
|
static void
|
|
evdns_request_remove(struct request *req, struct request **head)
|
|
{
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
|
|
#if 0
|
|
{
|
|
struct request *ptr;
|
|
int found = 0;
|
|
EVUTIL_ASSERT(*head != NULL);
|
|
|
|
ptr = *head;
|
|
do {
|
|
if (ptr == req) {
|
|
found = 1;
|
|
break;
|
|
}
|
|
ptr = ptr->next;
|
|
} while (ptr != *head);
|
|
EVUTIL_ASSERT(found);
|
|
|
|
EVUTIL_ASSERT(req->next);
|
|
}
|
|
#endif
|
|
|
|
if (req->next == req) {
|
|
/* only item in the list */
|
|
*head = NULL;
|
|
} else {
|
|
req->next->prev = req->prev;
|
|
req->prev->next = req->next;
|
|
if (*head == req) *head = req->next;
|
|
}
|
|
req->next = req->prev = NULL;
|
|
}
|
|
|
|
/* insert into the tail of the queue */
|
|
static void
|
|
evdns_request_insert(struct request *req, struct request **head) {
|
|
ASSERT_LOCKED(req->base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
if (!*head) {
|
|
*head = req;
|
|
req->next = req->prev = req;
|
|
return;
|
|
}
|
|
|
|
req->prev = (*head)->prev;
|
|
req->prev->next = req;
|
|
req->next = *head;
|
|
(*head)->prev = req;
|
|
}
|
|
|
|
static int
|
|
string_num_dots(const char *s) {
|
|
int count = 0;
|
|
while ((s = strchr(s, '.'))) {
|
|
s++;
|
|
count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static struct request *
|
|
request_new(struct evdns_base *base, struct evdns_request *handle, int type,
|
|
const char *name, int flags, evdns_callback_type callback,
|
|
void *user_ptr) {
|
|
|
|
const char issuing_now =
|
|
(base->global_requests_inflight < base->global_max_requests_inflight) ? 1 : 0;
|
|
|
|
const size_t name_len = strlen(name);
|
|
const size_t request_max_len = evdns_request_len(name_len);
|
|
const u16 trans_id = issuing_now ? transaction_id_pick(base) : 0xffff;
|
|
/* the request data is alloced in a single block with the header */
|
|
struct request *const req =
|
|
mm_malloc(sizeof(struct request) + request_max_len);
|
|
int rlen;
|
|
char namebuf[256];
|
|
(void) flags;
|
|
|
|
ASSERT_LOCKED(base);
|
|
|
|
if (!req) return NULL;
|
|
|
|
if (name_len >= sizeof(namebuf)) {
|
|
mm_free(req);
|
|
return NULL;
|
|
}
|
|
|
|
memset(req, 0, sizeof(struct request));
|
|
req->base = base;
|
|
|
|
evtimer_assign(&req->timeout_event, req->base->event_base, evdns_request_timeout_callback, req);
|
|
|
|
if (base->global_randomize_case) {
|
|
unsigned i;
|
|
char randbits[(sizeof(namebuf)+7)/8];
|
|
strlcpy(namebuf, name, sizeof(namebuf));
|
|
evutil_secure_rng_get_bytes(randbits, (name_len+7)/8);
|
|
for (i = 0; i < name_len; ++i) {
|
|
if (EVUTIL_ISALPHA_(namebuf[i])) {
|
|
if ((randbits[i >> 3] & (1<<(i & 7))))
|
|
namebuf[i] |= 0x20;
|
|
else
|
|
namebuf[i] &= ~0x20;
|
|
}
|
|
}
|
|
name = namebuf;
|
|
}
|
|
|
|
/* request data lives just after the header */
|
|
req->request = ((u8 *) req) + sizeof(struct request);
|
|
/* denotes that the request data shouldn't be free()ed */
|
|
req->request_appended = 1;
|
|
rlen = evdns_request_data_build(name, name_len, trans_id,
|
|
type, CLASS_INET, req->request, request_max_len);
|
|
if (rlen < 0)
|
|
goto err1;
|
|
|
|
req->request_len = rlen;
|
|
req->trans_id = trans_id;
|
|
req->tx_count = 0;
|
|
req->request_type = type;
|
|
req->user_pointer = user_ptr;
|
|
req->user_callback = callback;
|
|
req->ns = issuing_now ? nameserver_pick(base) : NULL;
|
|
req->next = req->prev = NULL;
|
|
req->handle = handle;
|
|
if (handle) {
|
|
handle->current_req = req;
|
|
handle->base = base;
|
|
}
|
|
|
|
return req;
|
|
err1:
|
|
mm_free(req);
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
request_submit(struct request *const req) {
|
|
struct evdns_base *base = req->base;
|
|
ASSERT_LOCKED(base);
|
|
ASSERT_VALID_REQUEST(req);
|
|
if (req->ns) {
|
|
/* if it has a nameserver assigned then this is going */
|
|
/* straight into the inflight queue */
|
|
evdns_request_insert(req, &REQ_HEAD(base, req->trans_id));
|
|
|
|
base->global_requests_inflight++;
|
|
req->ns->requests_inflight++;
|
|
|
|
evdns_request_transmit(req);
|
|
} else {
|
|
evdns_request_insert(req, &base->req_waiting_head);
|
|
base->global_requests_waiting++;
|
|
}
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_cancel_request(struct evdns_base *base, struct evdns_request *handle)
|
|
{
|
|
struct request *req;
|
|
|
|
if (!handle->current_req)
|
|
return;
|
|
|
|
if (!base) {
|
|
/* This redundancy is silly; can we fix it? (Not for 2.0) XXXX */
|
|
base = handle->base;
|
|
if (!base)
|
|
base = handle->current_req->base;
|
|
}
|
|
|
|
EVDNS_LOCK(base);
|
|
if (handle->pending_cb) {
|
|
EVDNS_UNLOCK(base);
|
|
return;
|
|
}
|
|
|
|
req = handle->current_req;
|
|
ASSERT_VALID_REQUEST(req);
|
|
|
|
reply_schedule_callback(req, 0, DNS_ERR_CANCEL, NULL);
|
|
if (req->ns) {
|
|
/* remove from inflight queue */
|
|
request_finished(req, &REQ_HEAD(base, req->trans_id), 1);
|
|
} else {
|
|
/* remove from global_waiting head */
|
|
request_finished(req, &base->req_waiting_head, 1);
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
|
|
/* exported function */
|
|
struct evdns_request *
|
|
evdns_base_resolve_ipv4(struct evdns_base *base, const char *name, int flags,
|
|
evdns_callback_type callback, void *ptr) {
|
|
struct evdns_request *handle;
|
|
struct request *req;
|
|
log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
|
|
handle = mm_calloc(1, sizeof(*handle));
|
|
if (handle == NULL)
|
|
return NULL;
|
|
EVDNS_LOCK(base);
|
|
if (flags & DNS_QUERY_NO_SEARCH) {
|
|
req =
|
|
request_new(base, handle, TYPE_A, name, flags,
|
|
callback, ptr);
|
|
if (req)
|
|
request_submit(req);
|
|
} else {
|
|
search_request_new(base, handle, TYPE_A, name, flags,
|
|
callback, ptr);
|
|
}
|
|
if (handle->current_req == NULL) {
|
|
mm_free(handle);
|
|
handle = NULL;
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
return handle;
|
|
}
|
|
|
|
int evdns_resolve_ipv4(const char *name, int flags,
|
|
evdns_callback_type callback, void *ptr)
|
|
{
|
|
return evdns_base_resolve_ipv4(current_base, name, flags, callback, ptr)
|
|
? 0 : -1;
|
|
}
|
|
|
|
|
|
/* exported function */
|
|
struct evdns_request *
|
|
evdns_base_resolve_ipv6(struct evdns_base *base,
|
|
const char *name, int flags,
|
|
evdns_callback_type callback, void *ptr)
|
|
{
|
|
struct evdns_request *handle;
|
|
struct request *req;
|
|
log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
|
|
handle = mm_calloc(1, sizeof(*handle));
|
|
if (handle == NULL)
|
|
return NULL;
|
|
EVDNS_LOCK(base);
|
|
if (flags & DNS_QUERY_NO_SEARCH) {
|
|
req = request_new(base, handle, TYPE_AAAA, name, flags,
|
|
callback, ptr);
|
|
if (req)
|
|
request_submit(req);
|
|
} else {
|
|
search_request_new(base, handle, TYPE_AAAA, name, flags,
|
|
callback, ptr);
|
|
}
|
|
if (handle->current_req == NULL) {
|
|
mm_free(handle);
|
|
handle = NULL;
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
return handle;
|
|
}
|
|
|
|
int evdns_resolve_ipv6(const char *name, int flags,
|
|
evdns_callback_type callback, void *ptr) {
|
|
return evdns_base_resolve_ipv6(current_base, name, flags, callback, ptr)
|
|
? 0 : -1;
|
|
}
|
|
|
|
struct evdns_request *
|
|
evdns_base_resolve_reverse(struct evdns_base *base, const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
|
char buf[32];
|
|
struct evdns_request *handle;
|
|
struct request *req;
|
|
u32 a;
|
|
EVUTIL_ASSERT(in);
|
|
a = ntohl(in->s_addr);
|
|
evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
|
|
(int)(u8)((a )&0xff),
|
|
(int)(u8)((a>>8 )&0xff),
|
|
(int)(u8)((a>>16)&0xff),
|
|
(int)(u8)((a>>24)&0xff));
|
|
handle = mm_calloc(1, sizeof(*handle));
|
|
if (handle == NULL)
|
|
return NULL;
|
|
log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
|
|
EVDNS_LOCK(base);
|
|
req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr);
|
|
if (req)
|
|
request_submit(req);
|
|
if (handle->current_req == NULL) {
|
|
mm_free(handle);
|
|
handle = NULL;
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
return (handle);
|
|
}
|
|
|
|
int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
|
return evdns_base_resolve_reverse(current_base, in, flags, callback, ptr)
|
|
? 0 : -1;
|
|
}
|
|
|
|
struct evdns_request *
|
|
evdns_base_resolve_reverse_ipv6(struct evdns_base *base, const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
|
/* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
|
|
char buf[73];
|
|
char *cp;
|
|
struct evdns_request *handle;
|
|
struct request *req;
|
|
int i;
|
|
EVUTIL_ASSERT(in);
|
|
cp = buf;
|
|
for (i=15; i >= 0; --i) {
|
|
u8 byte = in->s6_addr[i];
|
|
*cp++ = "0123456789abcdef"[byte & 0x0f];
|
|
*cp++ = '.';
|
|
*cp++ = "0123456789abcdef"[byte >> 4];
|
|
*cp++ = '.';
|
|
}
|
|
EVUTIL_ASSERT(cp + strlen("ip6.arpa") < buf+sizeof(buf));
|
|
memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1);
|
|
handle = mm_calloc(1, sizeof(*handle));
|
|
if (handle == NULL)
|
|
return NULL;
|
|
log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
|
|
EVDNS_LOCK(base);
|
|
req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr);
|
|
if (req)
|
|
request_submit(req);
|
|
if (handle->current_req == NULL) {
|
|
mm_free(handle);
|
|
handle = NULL;
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
return (handle);
|
|
}
|
|
|
|
int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
|
|
return evdns_base_resolve_reverse_ipv6(current_base, in, flags, callback, ptr)
|
|
? 0 : -1;
|
|
}
|
|
|
|
/* ================================================================= */
|
|
/* Search support */
|
|
/* */
|
|
/* the libc resolver has support for searching a number of domains */
|
|
/* to find a name. If nothing else then it takes the single domain */
|
|
/* from the gethostname() call. */
|
|
/* */
|
|
/* It can also be configured via the domain and search options in a */
|
|
/* resolv.conf. */
|
|
/* */
|
|
/* The ndots option controls how many dots it takes for the resolver */
|
|
/* to decide that a name is non-local and so try a raw lookup first. */
|
|
|
|
struct search_domain {
|
|
int len;
|
|
struct search_domain *next;
|
|
/* the text string is appended to this structure */
|
|
};
|
|
|
|
struct search_state {
|
|
int refcount;
|
|
int ndots;
|
|
int num_domains;
|
|
struct search_domain *head;
|
|
};
|
|
|
|
static void
|
|
search_state_decref(struct search_state *const state) {
|
|
if (!state) return;
|
|
state->refcount--;
|
|
if (!state->refcount) {
|
|
struct search_domain *next, *dom;
|
|
for (dom = state->head; dom; dom = next) {
|
|
next = dom->next;
|
|
mm_free(dom);
|
|
}
|
|
mm_free(state);
|
|
}
|
|
}
|
|
|
|
static struct search_state *
|
|
search_state_new(void) {
|
|
struct search_state *state = (struct search_state *) mm_malloc(sizeof(struct search_state));
|
|
if (!state) return NULL;
|
|
memset(state, 0, sizeof(struct search_state));
|
|
state->refcount = 1;
|
|
state->ndots = 1;
|
|
|
|
return state;
|
|
}
|
|
|
|
static void
|
|
search_postfix_clear(struct evdns_base *base) {
|
|
search_state_decref(base->global_search_state);
|
|
|
|
base->global_search_state = search_state_new();
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_base_search_clear(struct evdns_base *base)
|
|
{
|
|
EVDNS_LOCK(base);
|
|
search_postfix_clear(base);
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
|
|
void
|
|
evdns_search_clear(void) {
|
|
evdns_base_search_clear(current_base);
|
|
}
|
|
|
|
static void
|
|
search_postfix_add(struct evdns_base *base, const char *domain) {
|
|
size_t domain_len;
|
|
struct search_domain *sdomain;
|
|
while (domain[0] == '.') domain++;
|
|
domain_len = strlen(domain);
|
|
|
|
ASSERT_LOCKED(base);
|
|
if (!base->global_search_state) base->global_search_state = search_state_new();
|
|
if (!base->global_search_state) return;
|
|
base->global_search_state->num_domains++;
|
|
|
|
sdomain = (struct search_domain *) mm_malloc(sizeof(struct search_domain) + domain_len);
|
|
if (!sdomain) return;
|
|
memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len);
|
|
sdomain->next = base->global_search_state->head;
|
|
sdomain->len = (int) domain_len;
|
|
|
|
base->global_search_state->head = sdomain;
|
|
}
|
|
|
|
/* reverse the order of members in the postfix list. This is needed because, */
|
|
/* when parsing resolv.conf we push elements in the wrong order */
|
|
static void
|
|
search_reverse(struct evdns_base *base) {
|
|
struct search_domain *cur, *prev = NULL, *next;
|
|
ASSERT_LOCKED(base);
|
|
cur = base->global_search_state->head;
|
|
while (cur) {
|
|
next = cur->next;
|
|
cur->next = prev;
|
|
prev = cur;
|
|
cur = next;
|
|
}
|
|
|
|
base->global_search_state->head = prev;
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_base_search_add(struct evdns_base *base, const char *domain) {
|
|
EVDNS_LOCK(base);
|
|
search_postfix_add(base, domain);
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
void
|
|
evdns_search_add(const char *domain) {
|
|
evdns_base_search_add(current_base, domain);
|
|
}
|
|
|
|
/* exported function */
|
|
void
|
|
evdns_base_search_ndots_set(struct evdns_base *base, const int ndots) {
|
|
EVDNS_LOCK(base);
|
|
if (!base->global_search_state) base->global_search_state = search_state_new();
|
|
if (base->global_search_state)
|
|
base->global_search_state->ndots = ndots;
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
void
|
|
evdns_search_ndots_set(const int ndots) {
|
|
evdns_base_search_ndots_set(current_base, ndots);
|
|
}
|
|
|
|
static void
|
|
search_set_from_hostname(struct evdns_base *base) {
|
|
char hostname[HOST_NAME_MAX + 1], *domainname;
|
|
|
|
ASSERT_LOCKED(base);
|
|
search_postfix_clear(base);
|
|
if (gethostname(hostname, sizeof(hostname))) return;
|
|
domainname = strchr(hostname, '.');
|
|
if (!domainname) return;
|
|
search_postfix_add(base, domainname);
|
|
}
|
|
|
|
/* warning: returns malloced string */
|
|
static char *
|
|
search_make_new(const struct search_state *const state, int n, const char *const base_name) {
|
|
const size_t base_len = strlen(base_name);
|
|
char need_to_append_dot;
|
|
struct search_domain *dom;
|
|
|
|
if (!base_len) return NULL;
|
|
need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1;
|
|
|
|
for (dom = state->head; dom; dom = dom->next) {
|
|
if (!n--) {
|
|
/* this is the postfix we want */
|
|
/* the actual postfix string is kept at the end of the structure */
|
|
const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain);
|
|
const int postfix_len = dom->len;
|
|
char *const newname = (char *) mm_malloc(base_len + need_to_append_dot + postfix_len + 1);
|
|
if (!newname) return NULL;
|
|
memcpy(newname, base_name, base_len);
|
|
if (need_to_append_dot) newname[base_len] = '.';
|
|
memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len);
|
|
newname[base_len + need_to_append_dot + postfix_len] = 0;
|
|
return newname;
|
|
}
|
|
}
|
|
|
|
/* we ran off the end of the list and still didn't find the requested string */
|
|
EVUTIL_ASSERT(0);
|
|
return NULL; /* unreachable; stops warnings in some compilers. */
|
|
}
|
|
|
|
static struct request *
|
|
search_request_new(struct evdns_base *base, struct evdns_request *handle,
|
|
int type, const char *const name, int flags,
|
|
evdns_callback_type user_callback, void *user_arg) {
|
|
ASSERT_LOCKED(base);
|
|
EVUTIL_ASSERT(type == TYPE_A || type == TYPE_AAAA);
|
|
EVUTIL_ASSERT(handle->current_req == NULL);
|
|
if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) &&
|
|
base->global_search_state &&
|
|
base->global_search_state->num_domains) {
|
|
/* we have some domains to search */
|
|
struct request *req;
|
|
if (string_num_dots(name) >= base->global_search_state->ndots) {
|
|
req = request_new(base, handle, type, name, flags, user_callback, user_arg);
|
|
if (!req) return NULL;
|
|
handle->search_index = -1;
|
|
} else {
|
|
char *const new_name = search_make_new(base->global_search_state, 0, name);
|
|
if (!new_name) return NULL;
|
|
req = request_new(base, handle, type, new_name, flags, user_callback, user_arg);
|
|
mm_free(new_name);
|
|
if (!req) return NULL;
|
|
handle->search_index = 0;
|
|
}
|
|
EVUTIL_ASSERT(handle->search_origname == NULL);
|
|
handle->search_origname = mm_strdup(name);
|
|
if (handle->search_origname == NULL) {
|
|
/* XXX Should we dealloc req? If yes, how? */
|
|
if (req)
|
|
mm_free(req);
|
|
return NULL;
|
|
}
|
|
handle->search_state = base->global_search_state;
|
|
handle->search_flags = flags;
|
|
base->global_search_state->refcount++;
|
|
request_submit(req);
|
|
return req;
|
|
} else {
|
|
struct request *const req = request_new(base, handle, type, name, flags, user_callback, user_arg);
|
|
if (!req) return NULL;
|
|
request_submit(req);
|
|
return req;
|
|
}
|
|
}
|
|
|
|
/* this is called when a request has failed to find a name. We need to check */
|
|
/* if it is part of a search and, if so, try the next name in the list */
|
|
/* returns: */
|
|
/* 0 another request has been submitted */
|
|
/* 1 no more requests needed */
|
|
static int
|
|
search_try_next(struct evdns_request *const handle) {
|
|
struct request *req = handle->current_req;
|
|
struct evdns_base *base = req->base;
|
|
struct request *newreq;
|
|
ASSERT_LOCKED(base);
|
|
if (handle->search_state) {
|
|
/* it is part of a search */
|
|
char *new_name;
|
|
handle->search_index++;
|
|
if (handle->search_index >= handle->search_state->num_domains) {
|
|
/* no more postfixes to try, however we may need to try */
|
|
/* this name without a postfix */
|
|
if (string_num_dots(handle->search_origname) < handle->search_state->ndots) {
|
|
/* yep, we need to try it raw */
|
|
newreq = request_new(base, NULL, req->request_type, handle->search_origname, handle->search_flags, req->user_callback, req->user_pointer);
|
|
log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", handle->search_origname);
|
|
if (newreq) {
|
|
search_request_finished(handle);
|
|
goto submit_next;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
new_name = search_make_new(handle->search_state, handle->search_index, handle->search_origname);
|
|
if (!new_name) return 1;
|
|
log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, handle->search_index);
|
|
newreq = request_new(base, NULL, req->request_type, new_name, handle->search_flags, req->user_callback, req->user_pointer);
|
|
mm_free(new_name);
|
|
if (!newreq) return 1;
|
|
goto submit_next;
|
|
}
|
|
return 1;
|
|
|
|
submit_next:
|
|
request_finished(req, &REQ_HEAD(req->base, req->trans_id), 0);
|
|
handle->current_req = newreq;
|
|
newreq->handle = handle;
|
|
request_submit(newreq);
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
search_request_finished(struct evdns_request *const handle) {
|
|
ASSERT_LOCKED(handle->current_req->base);
|
|
if (handle->search_state) {
|
|
search_state_decref(handle->search_state);
|
|
handle->search_state = NULL;
|
|
}
|
|
if (handle->search_origname) {
|
|
mm_free(handle->search_origname);
|
|
handle->search_origname = NULL;
|
|
}
|
|
}
|
|
|
|
/* ================================================================= */
|
|
/* Parsing resolv.conf files */
|
|
|
|
static void
|
|
evdns_resolv_set_defaults(struct evdns_base *base, int flags) {
|
|
int add_default = flags & DNS_OPTION_NAMESERVERS;
|
|
if (flags & DNS_OPTION_NAMESERVERS_NO_DEFAULT)
|
|
add_default = 0;
|
|
|
|
/* if the file isn't found then we assume a local resolver */
|
|
ASSERT_LOCKED(base);
|
|
if (flags & DNS_OPTION_SEARCH)
|
|
search_set_from_hostname(base);
|
|
if (add_default)
|
|
evdns_base_nameserver_ip_add(base, "127.0.0.1");
|
|
}
|
|
|
|
#ifndef EVENT__HAVE_STRTOK_R
|
|
static char *
|
|
strtok_r(char *s, const char *delim, char **state) {
|
|
char *cp, *start;
|
|
start = cp = s ? s : *state;
|
|
if (!cp)
|
|
return NULL;
|
|
while (*cp && !strchr(delim, *cp))
|
|
++cp;
|
|
if (!*cp) {
|
|
if (cp == start)
|
|
return NULL;
|
|
*state = NULL;
|
|
return start;
|
|
} else {
|
|
*cp++ = '\0';
|
|
*state = cp;
|
|
return start;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* helper version of atoi which returns -1 on error */
|
|
static int
|
|
strtoint(const char *const str)
|
|
{
|
|
char *endptr;
|
|
const int r = strtol(str, &endptr, 10);
|
|
if (*endptr) return -1;
|
|
return r;
|
|
}
|
|
|
|
/* Parse a number of seconds into a timeval; return -1 on error. */
|
|
static int
|
|
evdns_strtotimeval(const char *const str, struct timeval *out)
|
|
{
|
|
double d;
|
|
char *endptr;
|
|
d = strtod(str, &endptr);
|
|
if (*endptr) return -1;
|
|
if (d < 0) return -1;
|
|
out->tv_sec = (int) d;
|
|
out->tv_usec = (int) ((d - (int) d)*1000000);
|
|
if (out->tv_sec == 0 && out->tv_usec < 1000) /* less than 1 msec */
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
/* helper version of atoi that returns -1 on error and clips to bounds. */
|
|
static int
|
|
strtoint_clipped(const char *const str, int min, int max)
|
|
{
|
|
int r = strtoint(str);
|
|
if (r == -1)
|
|
return r;
|
|
else if (r<min)
|
|
return min;
|
|
else if (r>max)
|
|
return max;
|
|
else
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
evdns_base_set_max_requests_inflight(struct evdns_base *base, int maxinflight)
|
|
{
|
|
int old_n_heads = base->n_req_heads, n_heads;
|
|
struct request **old_heads = base->req_heads, **new_heads, *req;
|
|
int i;
|
|
|
|
ASSERT_LOCKED(base);
|
|
if (maxinflight < 1)
|
|
maxinflight = 1;
|
|
n_heads = (maxinflight+4) / 5;
|
|
EVUTIL_ASSERT(n_heads > 0);
|
|
new_heads = mm_calloc(n_heads, sizeof(struct request*));
|
|
if (!new_heads)
|
|
return (-1);
|
|
if (old_heads) {
|
|
for (i = 0; i < old_n_heads; ++i) {
|
|
while (old_heads[i]) {
|
|
req = old_heads[i];
|
|
evdns_request_remove(req, &old_heads[i]);
|
|
evdns_request_insert(req, &new_heads[req->trans_id % n_heads]);
|
|
}
|
|
}
|
|
mm_free(old_heads);
|
|
}
|
|
base->req_heads = new_heads;
|
|
base->n_req_heads = n_heads;
|
|
base->global_max_requests_inflight = maxinflight;
|
|
return (0);
|
|
}
|
|
|
|
/* exported function */
|
|
int
|
|
evdns_base_set_option(struct evdns_base *base,
|
|
const char *option, const char *val)
|
|
{
|
|
int res;
|
|
EVDNS_LOCK(base);
|
|
res = evdns_base_set_option_impl(base, option, val, DNS_OPTIONS_ALL);
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
static inline int
|
|
str_matches_option(const char *s1, const char *optionname)
|
|
{
|
|
/* Option names are given as "option:" We accept either 'option' in
|
|
* s1, or 'option:randomjunk'. The latter form is to implement the
|
|
* resolv.conf parser. */
|
|
size_t optlen = strlen(optionname);
|
|
size_t slen = strlen(s1);
|
|
if (slen == optlen || slen == optlen - 1)
|
|
return !strncmp(s1, optionname, slen);
|
|
else if (slen > optlen)
|
|
return !strncmp(s1, optionname, optlen);
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
evdns_base_set_option_impl(struct evdns_base *base,
|
|
const char *option, const char *val, int flags)
|
|
{
|
|
ASSERT_LOCKED(base);
|
|
if (str_matches_option(option, "ndots:")) {
|
|
const int ndots = strtoint(val);
|
|
if (ndots == -1) return -1;
|
|
if (!(flags & DNS_OPTION_SEARCH)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
|
|
if (!base->global_search_state) base->global_search_state = search_state_new();
|
|
if (!base->global_search_state) return -1;
|
|
base->global_search_state->ndots = ndots;
|
|
} else if (str_matches_option(option, "timeout:")) {
|
|
struct timeval tv;
|
|
if (evdns_strtotimeval(val, &tv) == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting timeout to %s", val);
|
|
memcpy(&base->global_timeout, &tv, sizeof(struct timeval));
|
|
} else if (str_matches_option(option, "getaddrinfo-allow-skew:")) {
|
|
struct timeval tv;
|
|
if (evdns_strtotimeval(val, &tv) == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting getaddrinfo-allow-skew to %s",
|
|
val);
|
|
memcpy(&base->global_getaddrinfo_allow_skew, &tv,
|
|
sizeof(struct timeval));
|
|
} else if (str_matches_option(option, "max-timeouts:")) {
|
|
const int maxtimeout = strtoint_clipped(val, 1, 255);
|
|
if (maxtimeout == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
|
|
maxtimeout);
|
|
base->global_max_nameserver_timeout = maxtimeout;
|
|
} else if (str_matches_option(option, "max-inflight:")) {
|
|
const int maxinflight = strtoint_clipped(val, 1, 65000);
|
|
if (maxinflight == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
|
|
maxinflight);
|
|
evdns_base_set_max_requests_inflight(base, maxinflight);
|
|
} else if (str_matches_option(option, "attempts:")) {
|
|
int retries = strtoint(val);
|
|
if (retries == -1) return -1;
|
|
if (retries > 255) retries = 255;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
|
|
base->global_max_retransmits = retries;
|
|
} else if (str_matches_option(option, "randomize-case:")) {
|
|
int randcase = strtoint(val);
|
|
if (randcase == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
base->global_randomize_case = randcase;
|
|
} else if (str_matches_option(option, "bind-to:")) {
|
|
/* XXX This only applies to successive nameservers, not
|
|
* to already-configured ones. We might want to fix that. */
|
|
int len = sizeof(base->global_outgoing_address);
|
|
if (!(flags & DNS_OPTION_NAMESERVERS)) return 0;
|
|
if (evutil_parse_sockaddr_port(val,
|
|
(struct sockaddr*)&base->global_outgoing_address, &len))
|
|
return -1;
|
|
base->global_outgoing_addrlen = len;
|
|
} else if (str_matches_option(option, "initial-probe-timeout:")) {
|
|
struct timeval tv;
|
|
if (evdns_strtotimeval(val, &tv) == -1) return -1;
|
|
if (tv.tv_sec > 3600)
|
|
tv.tv_sec = 3600;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting initial probe timeout to %s",
|
|
val);
|
|
memcpy(&base->global_nameserver_probe_initial_timeout, &tv,
|
|
sizeof(tv));
|
|
} else if (str_matches_option(option, "so-rcvbuf:")) {
|
|
int buf = strtoint(val);
|
|
if (buf == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting SO_RCVBUF to %s", val);
|
|
base->so_rcvbuf = buf;
|
|
} else if (str_matches_option(option, "so-sndbuf:")) {
|
|
int buf = strtoint(val);
|
|
if (buf == -1) return -1;
|
|
if (!(flags & DNS_OPTION_MISC)) return 0;
|
|
log(EVDNS_LOG_DEBUG, "Setting SO_SNDBUF to %s", val);
|
|
base->so_sndbuf = buf;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
evdns_set_option(const char *option, const char *val, int flags)
|
|
{
|
|
if (!current_base)
|
|
current_base = evdns_base_new(NULL, 0);
|
|
return evdns_base_set_option(current_base, option, val);
|
|
}
|
|
|
|
static void
|
|
resolv_conf_parse_line(struct evdns_base *base, char *const start, int flags) {
|
|
char *strtok_state;
|
|
static const char *const delims = " \t";
|
|
#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
|
|
|
|
|
|
char *const first_token = strtok_r(start, delims, &strtok_state);
|
|
ASSERT_LOCKED(base);
|
|
if (!first_token) return;
|
|
|
|
if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
|
|
const char *const nameserver = NEXT_TOKEN;
|
|
|
|
if (nameserver)
|
|
evdns_base_nameserver_ip_add(base, nameserver);
|
|
} else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) {
|
|
const char *const domain = NEXT_TOKEN;
|
|
if (domain) {
|
|
search_postfix_clear(base);
|
|
search_postfix_add(base, domain);
|
|
}
|
|
} else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) {
|
|
const char *domain;
|
|
search_postfix_clear(base);
|
|
|
|
while ((domain = NEXT_TOKEN)) {
|
|
search_postfix_add(base, domain);
|
|
}
|
|
search_reverse(base);
|
|
} else if (!strcmp(first_token, "options")) {
|
|
const char *option;
|
|
while ((option = NEXT_TOKEN)) {
|
|
const char *val = strchr(option, ':');
|
|
evdns_base_set_option_impl(base, option, val ? val+1 : "", flags);
|
|
}
|
|
}
|
|
#undef NEXT_TOKEN
|
|
}
|
|
|
|
/* exported function */
|
|
/* returns: */
|
|
/* 0 no errors */
|
|
/* 1 failed to open file */
|
|
/* 2 failed to stat file */
|
|
/* 3 file too large */
|
|
/* 4 out of memory */
|
|
/* 5 short read from file */
|
|
int
|
|
evdns_base_resolv_conf_parse(struct evdns_base *base, int flags, const char *const filename) {
|
|
int res;
|
|
EVDNS_LOCK(base);
|
|
res = evdns_base_resolv_conf_parse_impl(base, flags, filename);
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
static char *
|
|
evdns_get_default_hosts_filename(void)
|
|
{
|
|
#ifdef _WIN32
|
|
/* Windows is a little coy about where it puts its configuration
|
|
* files. Sure, they're _usually_ in C:\windows\system32, but
|
|
* there's no reason in principle they couldn't be in
|
|
* W:\hoboken chicken emergency\
|
|
*/
|
|
char path[MAX_PATH+1];
|
|
static const char hostfile[] = "\\drivers\\etc\\hosts";
|
|
char *path_out;
|
|
size_t len_out;
|
|
|
|
if (! SHGetSpecialFolderPathA(NULL, path, CSIDL_SYSTEM, 0))
|
|
return NULL;
|
|
len_out = strlen(path)+strlen(hostfile)+1;
|
|
path_out = mm_malloc(len_out);
|
|
evutil_snprintf(path_out, len_out, "%s%s", path, hostfile);
|
|
return path_out;
|
|
#else
|
|
return mm_strdup("/etc/hosts");
|
|
#endif
|
|
}
|
|
|
|
static int
|
|
evdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename) {
|
|
size_t n;
|
|
char *resolv;
|
|
char *start;
|
|
int err = 0;
|
|
int add_default;
|
|
|
|
log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename);
|
|
|
|
add_default = flags & DNS_OPTION_NAMESERVERS;
|
|
if (flags & DNS_OPTION_NAMESERVERS_NO_DEFAULT)
|
|
add_default = 0;
|
|
|
|
if (flags & DNS_OPTION_HOSTSFILE) {
|
|
char *fname = evdns_get_default_hosts_filename();
|
|
evdns_base_load_hosts(base, fname);
|
|
if (fname)
|
|
mm_free(fname);
|
|
}
|
|
|
|
if (!filename) {
|
|
evdns_resolv_set_defaults(base, flags);
|
|
return 1;
|
|
}
|
|
|
|
if ((err = evutil_read_file_(filename, &resolv, &n, 0)) < 0) {
|
|
if (err == -1) {
|
|
/* No file. */
|
|
evdns_resolv_set_defaults(base, flags);
|
|
return 1;
|
|
} else {
|
|
return 2;
|
|
}
|
|
}
|
|
|
|
start = resolv;
|
|
for (;;) {
|
|
char *const newline = strchr(start, '\n');
|
|
if (!newline) {
|
|
resolv_conf_parse_line(base, start, flags);
|
|
break;
|
|
} else {
|
|
*newline = 0;
|
|
resolv_conf_parse_line(base, start, flags);
|
|
start = newline + 1;
|
|
}
|
|
}
|
|
|
|
if (!base->server_head && add_default) {
|
|
/* no nameservers were configured. */
|
|
evdns_base_nameserver_ip_add(base, "127.0.0.1");
|
|
err = 6;
|
|
}
|
|
if (flags & DNS_OPTION_SEARCH && (!base->global_search_state || base->global_search_state->num_domains == 0)) {
|
|
search_set_from_hostname(base);
|
|
}
|
|
|
|
mm_free(resolv);
|
|
return err;
|
|
}
|
|
|
|
int
|
|
evdns_resolv_conf_parse(int flags, const char *const filename) {
|
|
if (!current_base)
|
|
current_base = evdns_base_new(NULL, 0);
|
|
return evdns_base_resolv_conf_parse(current_base, flags, filename);
|
|
}
|
|
|
|
|
|
#ifdef _WIN32
|
|
/* Add multiple nameservers from a space-or-comma-separated list. */
|
|
static int
|
|
evdns_nameserver_ip_add_line(struct evdns_base *base, const char *ips) {
|
|
const char *addr;
|
|
char *buf;
|
|
int r;
|
|
ASSERT_LOCKED(base);
|
|
while (*ips) {
|
|
while (isspace(*ips) || *ips == ',' || *ips == '\t')
|
|
++ips;
|
|
addr = ips;
|
|
while (isdigit(*ips) || *ips == '.' || *ips == ':' ||
|
|
*ips=='[' || *ips==']')
|
|
++ips;
|
|
buf = mm_malloc(ips-addr+1);
|
|
if (!buf) return 4;
|
|
memcpy(buf, addr, ips-addr);
|
|
buf[ips-addr] = '\0';
|
|
r = evdns_base_nameserver_ip_add(base, buf);
|
|
mm_free(buf);
|
|
if (r) return r;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
typedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*);
|
|
|
|
/* Use the windows GetNetworkParams interface in iphlpapi.dll to */
|
|
/* figure out what our nameservers are. */
|
|
static int
|
|
load_nameservers_with_getnetworkparams(struct evdns_base *base)
|
|
{
|
|
/* Based on MSDN examples and inspection of c-ares code. */
|
|
FIXED_INFO *fixed;
|
|
HMODULE handle = 0;
|
|
ULONG size = sizeof(FIXED_INFO);
|
|
void *buf = NULL;
|
|
int status = 0, r, added_any;
|
|
IP_ADDR_STRING *ns;
|
|
GetNetworkParams_fn_t fn;
|
|
|
|
ASSERT_LOCKED(base);
|
|
if (!(handle = evutil_load_windows_system_library_(
|
|
TEXT("iphlpapi.dll")))) {
|
|
log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll");
|
|
status = -1;
|
|
goto done;
|
|
}
|
|
if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, "GetNetworkParams"))) {
|
|
log(EVDNS_LOG_WARN, "Could not get address of function.");
|
|
status = -1;
|
|
goto done;
|
|
}
|
|
|
|
buf = mm_malloc(size);
|
|
if (!buf) { status = 4; goto done; }
|
|
fixed = buf;
|
|
r = fn(fixed, &size);
|
|
if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) {
|
|
status = -1;
|
|
goto done;
|
|
}
|
|
if (r != ERROR_SUCCESS) {
|
|
mm_free(buf);
|
|
buf = mm_malloc(size);
|
|
if (!buf) { status = 4; goto done; }
|
|
fixed = buf;
|
|
r = fn(fixed, &size);
|
|
if (r != ERROR_SUCCESS) {
|
|
log(EVDNS_LOG_DEBUG, "fn() failed.");
|
|
status = -1;
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
EVUTIL_ASSERT(fixed);
|
|
added_any = 0;
|
|
ns = &(fixed->DnsServerList);
|
|
while (ns) {
|
|
r = evdns_nameserver_ip_add_line(base, ns->IpAddress.String);
|
|
if (r) {
|
|
log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list,error: %d",
|
|
(ns->IpAddress.String),(int)GetLastError());
|
|
status = r;
|
|
} else {
|
|
++added_any;
|
|
log(EVDNS_LOG_DEBUG,"Successfully added %s as nameserver",ns->IpAddress.String);
|
|
}
|
|
|
|
ns = ns->Next;
|
|
}
|
|
|
|
if (!added_any) {
|
|
log(EVDNS_LOG_DEBUG, "No nameservers added.");
|
|
if (status == 0)
|
|
status = -1;
|
|
} else {
|
|
status = 0;
|
|
}
|
|
|
|
done:
|
|
if (buf)
|
|
mm_free(buf);
|
|
if (handle)
|
|
FreeLibrary(handle);
|
|
return status;
|
|
}
|
|
|
|
static int
|
|
config_nameserver_from_reg_key(struct evdns_base *base, HKEY key, const TCHAR *subkey)
|
|
{
|
|
char *buf;
|
|
DWORD bufsz = 0, type = 0;
|
|
int status = 0;
|
|
|
|
ASSERT_LOCKED(base);
|
|
if (RegQueryValueEx(key, subkey, 0, &type, NULL, &bufsz)
|
|
!= ERROR_MORE_DATA)
|
|
return -1;
|
|
if (!(buf = mm_malloc(bufsz)))
|
|
return -1;
|
|
|
|
if (RegQueryValueEx(key, subkey, 0, &type, (LPBYTE)buf, &bufsz)
|
|
== ERROR_SUCCESS && bufsz > 1) {
|
|
status = evdns_nameserver_ip_add_line(base,buf);
|
|
}
|
|
|
|
mm_free(buf);
|
|
return status;
|
|
}
|
|
|
|
#define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\")
|
|
#define WIN_NS_9X_KEY SERVICES_KEY TEXT("VxD\\MSTCP")
|
|
#define WIN_NS_NT_KEY SERVICES_KEY TEXT("Tcpip\\Parameters")
|
|
|
|
static int
|
|
load_nameservers_from_registry(struct evdns_base *base)
|
|
{
|
|
int found = 0;
|
|
int r;
|
|
#define TRY(k, name) \
|
|
if (!found && config_nameserver_from_reg_key(base,k,TEXT(name)) == 0) { \
|
|
log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
|
|
found = 1; \
|
|
} else if (!found) { \
|
|
log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
|
|
#k,#name); \
|
|
}
|
|
|
|
ASSERT_LOCKED(base);
|
|
|
|
if (((int)GetVersion()) > 0) { /* NT */
|
|
HKEY nt_key = 0, interfaces_key = 0;
|
|
|
|
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
|
|
KEY_READ, &nt_key) != ERROR_SUCCESS) {
|
|
log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError());
|
|
return -1;
|
|
}
|
|
r = RegOpenKeyEx(nt_key, TEXT("Interfaces"), 0,
|
|
KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS,
|
|
&interfaces_key);
|
|
if (r != ERROR_SUCCESS) {
|
|
log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError());
|
|
return -1;
|
|
}
|
|
TRY(nt_key, "NameServer");
|
|
TRY(nt_key, "DhcpNameServer");
|
|
TRY(interfaces_key, "NameServer");
|
|
TRY(interfaces_key, "DhcpNameServer");
|
|
RegCloseKey(interfaces_key);
|
|
RegCloseKey(nt_key);
|
|
} else {
|
|
HKEY win_key = 0;
|
|
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0,
|
|
KEY_READ, &win_key) != ERROR_SUCCESS) {
|
|
log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError());
|
|
return -1;
|
|
}
|
|
TRY(win_key, "NameServer");
|
|
RegCloseKey(win_key);
|
|
}
|
|
|
|
if (found == 0) {
|
|
log(EVDNS_LOG_WARN,"Didn't find any nameservers.");
|
|
}
|
|
|
|
return found ? 0 : -1;
|
|
#undef TRY
|
|
}
|
|
|
|
int
|
|
evdns_base_config_windows_nameservers(struct evdns_base *base)
|
|
{
|
|
int r;
|
|
char *fname;
|
|
if (base == NULL)
|
|
base = current_base;
|
|
if (base == NULL)
|
|
return -1;
|
|
EVDNS_LOCK(base);
|
|
fname = evdns_get_default_hosts_filename();
|
|
log(EVDNS_LOG_DEBUG, "Loading hosts entries from %s", fname);
|
|
evdns_base_load_hosts(base, fname);
|
|
if (fname)
|
|
mm_free(fname);
|
|
|
|
if (load_nameservers_with_getnetworkparams(base) == 0) {
|
|
EVDNS_UNLOCK(base);
|
|
return 0;
|
|
}
|
|
r = load_nameservers_from_registry(base);
|
|
|
|
EVDNS_UNLOCK(base);
|
|
return r;
|
|
}
|
|
|
|
int
|
|
evdns_config_windows_nameservers(void)
|
|
{
|
|
if (!current_base) {
|
|
current_base = evdns_base_new(NULL, 1);
|
|
return current_base == NULL ? -1 : 0;
|
|
} else {
|
|
return evdns_base_config_windows_nameservers(current_base);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
struct evdns_base *
|
|
evdns_base_new(struct event_base *event_base, int flags)
|
|
{
|
|
struct evdns_base *base;
|
|
|
|
if (evutil_secure_rng_init() < 0) {
|
|
log(EVDNS_LOG_WARN, "Unable to seed random number generator; "
|
|
"DNS can't run.");
|
|
return NULL;
|
|
}
|
|
|
|
/* Give the evutil library a hook into its evdns-enabled
|
|
* functionality. We can't just call evdns_getaddrinfo directly or
|
|
* else libevent-core will depend on libevent-extras. */
|
|
evutil_set_evdns_getaddrinfo_fn_(evdns_getaddrinfo);
|
|
evutil_set_evdns_getaddrinfo_cancel_fn_(evdns_getaddrinfo_cancel);
|
|
|
|
base = mm_malloc(sizeof(struct evdns_base));
|
|
if (base == NULL)
|
|
return (NULL);
|
|
memset(base, 0, sizeof(struct evdns_base));
|
|
base->req_waiting_head = NULL;
|
|
|
|
EVTHREAD_ALLOC_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
|
|
EVDNS_LOCK(base);
|
|
|
|
/* Set max requests inflight and allocate req_heads. */
|
|
base->req_heads = NULL;
|
|
|
|
evdns_base_set_max_requests_inflight(base, 64);
|
|
|
|
base->server_head = NULL;
|
|
base->event_base = event_base;
|
|
base->global_good_nameservers = base->global_requests_inflight =
|
|
base->global_requests_waiting = 0;
|
|
|
|
base->global_timeout.tv_sec = 5;
|
|
base->global_timeout.tv_usec = 0;
|
|
base->global_max_reissues = 1;
|
|
base->global_max_retransmits = 3;
|
|
base->global_max_nameserver_timeout = 3;
|
|
base->global_search_state = NULL;
|
|
base->global_randomize_case = 1;
|
|
base->global_getaddrinfo_allow_skew.tv_sec = 3;
|
|
base->global_getaddrinfo_allow_skew.tv_usec = 0;
|
|
base->global_nameserver_probe_initial_timeout.tv_sec = 10;
|
|
base->global_nameserver_probe_initial_timeout.tv_usec = 0;
|
|
|
|
TAILQ_INIT(&base->hostsdb);
|
|
|
|
#define EVDNS_BASE_ALL_FLAGS ( \
|
|
EVDNS_BASE_INITIALIZE_NAMESERVERS | \
|
|
EVDNS_BASE_DISABLE_WHEN_INACTIVE | \
|
|
EVDNS_BASE_NAMESERVERS_NO_DEFAULT | \
|
|
0)
|
|
|
|
if (flags & ~EVDNS_BASE_ALL_FLAGS) {
|
|
flags = EVDNS_BASE_INITIALIZE_NAMESERVERS;
|
|
log(EVDNS_LOG_WARN,
|
|
"Unrecognized flag passed to evdns_base_new(). Assuming "
|
|
"you meant EVDNS_BASE_INITIALIZE_NAMESERVERS.");
|
|
}
|
|
#undef EVDNS_BASE_ALL_FLAGS
|
|
|
|
if (flags & EVDNS_BASE_INITIALIZE_NAMESERVERS) {
|
|
int r;
|
|
int opts = DNS_OPTIONS_ALL;
|
|
if (flags & EVDNS_BASE_NAMESERVERS_NO_DEFAULT) {
|
|
opts |= DNS_OPTION_NAMESERVERS_NO_DEFAULT;
|
|
}
|
|
|
|
#ifdef _WIN32
|
|
r = evdns_base_config_windows_nameservers(base);
|
|
#else
|
|
r = evdns_base_resolv_conf_parse(base, opts, "/etc/resolv.conf");
|
|
#endif
|
|
if (r) {
|
|
evdns_base_free_and_unlock(base, 0);
|
|
return NULL;
|
|
}
|
|
}
|
|
if (flags & EVDNS_BASE_DISABLE_WHEN_INACTIVE) {
|
|
base->disable_when_inactive = 1;
|
|
}
|
|
|
|
EVDNS_UNLOCK(base);
|
|
return base;
|
|
}
|
|
|
|
int
|
|
evdns_init(void)
|
|
{
|
|
struct evdns_base *base = evdns_base_new(NULL, 1);
|
|
if (base) {
|
|
current_base = base;
|
|
return 0;
|
|
} else {
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
const char *
|
|
evdns_err_to_string(int err)
|
|
{
|
|
switch (err) {
|
|
case DNS_ERR_NONE: return "no error";
|
|
case DNS_ERR_FORMAT: return "misformatted query";
|
|
case DNS_ERR_SERVERFAILED: return "server failed";
|
|
case DNS_ERR_NOTEXIST: return "name does not exist";
|
|
case DNS_ERR_NOTIMPL: return "query not implemented";
|
|
case DNS_ERR_REFUSED: return "refused";
|
|
|
|
case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed";
|
|
case DNS_ERR_UNKNOWN: return "unknown";
|
|
case DNS_ERR_TIMEOUT: return "request timed out";
|
|
case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
|
|
case DNS_ERR_CANCEL: return "dns request canceled";
|
|
case DNS_ERR_NODATA: return "no records in the reply";
|
|
default: return "[Unknown error code]";
|
|
}
|
|
}
|
|
|
|
static void
|
|
evdns_nameserver_free(struct nameserver *server)
|
|
{
|
|
if (server->socket >= 0)
|
|
evutil_closesocket(server->socket);
|
|
(void) event_del(&server->event);
|
|
event_debug_unassign(&server->event);
|
|
if (server->state == 0)
|
|
(void) event_del(&server->timeout_event);
|
|
if (server->probe_request) {
|
|
evdns_cancel_request(server->base, server->probe_request);
|
|
server->probe_request = NULL;
|
|
}
|
|
event_debug_unassign(&server->timeout_event);
|
|
mm_free(server);
|
|
}
|
|
|
|
static void
|
|
evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests)
|
|
{
|
|
struct nameserver *server, *server_next;
|
|
struct search_domain *dom, *dom_next;
|
|
int i;
|
|
|
|
/* Requires that we hold the lock. */
|
|
|
|
/* TODO(nickm) we might need to refcount here. */
|
|
|
|
while (base->req_waiting_head) {
|
|
if (fail_requests)
|
|
reply_schedule_callback(base->req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL);
|
|
request_finished(base->req_waiting_head, &base->req_waiting_head, 1);
|
|
}
|
|
for (i = 0; i < base->n_req_heads; ++i) {
|
|
while (base->req_heads[i]) {
|
|
if (fail_requests)
|
|
reply_schedule_callback(base->req_heads[i], 0, DNS_ERR_SHUTDOWN, NULL);
|
|
request_finished(base->req_heads[i], &REQ_HEAD(base, base->req_heads[i]->trans_id), 1);
|
|
}
|
|
}
|
|
base->global_requests_inflight = base->global_requests_waiting = 0;
|
|
|
|
for (server = base->server_head; server; server = server_next) {
|
|
server_next = server->next;
|
|
/** already done something before */
|
|
server->probe_request = NULL;
|
|
evdns_nameserver_free(server);
|
|
if (server_next == base->server_head)
|
|
break;
|
|
}
|
|
base->server_head = NULL;
|
|
base->global_good_nameservers = 0;
|
|
|
|
if (base->global_search_state) {
|
|
for (dom = base->global_search_state->head; dom; dom = dom_next) {
|
|
dom_next = dom->next;
|
|
mm_free(dom);
|
|
}
|
|
mm_free(base->global_search_state);
|
|
base->global_search_state = NULL;
|
|
}
|
|
|
|
{
|
|
struct hosts_entry *victim;
|
|
while ((victim = TAILQ_FIRST(&base->hostsdb))) {
|
|
TAILQ_REMOVE(&base->hostsdb, victim, next);
|
|
mm_free(victim);
|
|
}
|
|
}
|
|
|
|
mm_free(base->req_heads);
|
|
|
|
EVDNS_UNLOCK(base);
|
|
EVTHREAD_FREE_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
|
|
|
|
mm_free(base);
|
|
}
|
|
|
|
void
|
|
evdns_base_free(struct evdns_base *base, int fail_requests)
|
|
{
|
|
EVDNS_LOCK(base);
|
|
evdns_base_free_and_unlock(base, fail_requests);
|
|
}
|
|
|
|
void
|
|
evdns_base_clear_host_addresses(struct evdns_base *base)
|
|
{
|
|
struct hosts_entry *victim;
|
|
EVDNS_LOCK(base);
|
|
while ((victim = TAILQ_FIRST(&base->hostsdb))) {
|
|
TAILQ_REMOVE(&base->hostsdb, victim, next);
|
|
mm_free(victim);
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
}
|
|
|
|
void
|
|
evdns_shutdown(int fail_requests)
|
|
{
|
|
if (current_base) {
|
|
struct evdns_base *b = current_base;
|
|
current_base = NULL;
|
|
evdns_base_free(b, fail_requests);
|
|
}
|
|
evdns_log_fn = NULL;
|
|
}
|
|
|
|
static int
|
|
evdns_base_parse_hosts_line(struct evdns_base *base, char *line)
|
|
{
|
|
char *strtok_state;
|
|
static const char *const delims = " \t";
|
|
char *const addr = strtok_r(line, delims, &strtok_state);
|
|
char *hostname, *hash;
|
|
struct sockaddr_storage ss;
|
|
int socklen = sizeof(ss);
|
|
ASSERT_LOCKED(base);
|
|
|
|
#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
|
|
|
|
if (!addr || *addr == '#')
|
|
return 0;
|
|
|
|
memset(&ss, 0, sizeof(ss));
|
|
if (evutil_parse_sockaddr_port(addr, (struct sockaddr*)&ss, &socklen)<0)
|
|
return -1;
|
|
if (socklen > (int)sizeof(struct sockaddr_in6))
|
|
return -1;
|
|
|
|
if (sockaddr_getport((struct sockaddr*)&ss))
|
|
return -1;
|
|
|
|
while ((hostname = NEXT_TOKEN)) {
|
|
struct hosts_entry *he;
|
|
size_t namelen;
|
|
if ((hash = strchr(hostname, '#'))) {
|
|
if (hash == hostname)
|
|
return 0;
|
|
*hash = '\0';
|
|
}
|
|
|
|
namelen = strlen(hostname);
|
|
|
|
he = mm_calloc(1, sizeof(struct hosts_entry)+namelen);
|
|
if (!he)
|
|
return -1;
|
|
EVUTIL_ASSERT(socklen <= (int)sizeof(he->addr));
|
|
memcpy(&he->addr, &ss, socklen);
|
|
memcpy(he->hostname, hostname, namelen+1);
|
|
he->addrlen = socklen;
|
|
|
|
TAILQ_INSERT_TAIL(&base->hostsdb, he, next);
|
|
|
|
if (hash)
|
|
return 0;
|
|
}
|
|
|
|
return 0;
|
|
#undef NEXT_TOKEN
|
|
}
|
|
|
|
static int
|
|
evdns_base_load_hosts_impl(struct evdns_base *base, const char *hosts_fname)
|
|
{
|
|
char *str=NULL, *cp, *eol;
|
|
size_t len;
|
|
int err=0;
|
|
|
|
ASSERT_LOCKED(base);
|
|
|
|
if (hosts_fname == NULL ||
|
|
(err = evutil_read_file_(hosts_fname, &str, &len, 0)) < 0) {
|
|
char tmp[64];
|
|
strlcpy(tmp, "127.0.0.1 localhost", sizeof(tmp));
|
|
evdns_base_parse_hosts_line(base, tmp);
|
|
strlcpy(tmp, "::1 localhost", sizeof(tmp));
|
|
evdns_base_parse_hosts_line(base, tmp);
|
|
return err ? -1 : 0;
|
|
}
|
|
|
|
/* This will break early if there is a NUL in the hosts file.
|
|
* Probably not a problem.*/
|
|
cp = str;
|
|
for (;;) {
|
|
eol = strchr(cp, '\n');
|
|
|
|
if (eol) {
|
|
*eol = '\0';
|
|
evdns_base_parse_hosts_line(base, cp);
|
|
cp = eol+1;
|
|
} else {
|
|
evdns_base_parse_hosts_line(base, cp);
|
|
break;
|
|
}
|
|
}
|
|
|
|
mm_free(str);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
evdns_base_load_hosts(struct evdns_base *base, const char *hosts_fname)
|
|
{
|
|
int res;
|
|
if (!base)
|
|
base = current_base;
|
|
EVDNS_LOCK(base);
|
|
res = evdns_base_load_hosts_impl(base, hosts_fname);
|
|
EVDNS_UNLOCK(base);
|
|
return res;
|
|
}
|
|
|
|
/* A single request for a getaddrinfo, either v4 or v6. */
|
|
struct getaddrinfo_subrequest {
|
|
struct evdns_request *r;
|
|
ev_uint32_t type;
|
|
};
|
|
|
|
/* State data used to implement an in-progress getaddrinfo. */
|
|
struct evdns_getaddrinfo_request {
|
|
struct evdns_base *evdns_base;
|
|
/* Copy of the modified 'hints' data that we'll use to build
|
|
* answers. */
|
|
struct evutil_addrinfo hints;
|
|
/* The callback to invoke when we're done */
|
|
evdns_getaddrinfo_cb user_cb;
|
|
/* User-supplied data to give to the callback. */
|
|
void *user_data;
|
|
/* The port to use when building sockaddrs. */
|
|
ev_uint16_t port;
|
|
/* The sub_request for an A record (if any) */
|
|
struct getaddrinfo_subrequest ipv4_request;
|
|
/* The sub_request for an AAAA record (if any) */
|
|
struct getaddrinfo_subrequest ipv6_request;
|
|
|
|
/* The cname result that we were told (if any) */
|
|
char *cname_result;
|
|
|
|
/* If we have one request answered and one request still inflight,
|
|
* then this field holds the answer from the first request... */
|
|
struct evutil_addrinfo *pending_result;
|
|
/* And this event is a timeout that will tell us to cancel the second
|
|
* request if it's taking a long time. */
|
|
struct event timeout;
|
|
|
|
/* And this field holds the error code from the first request... */
|
|
int pending_error;
|
|
/* If this is set, the user canceled this request. */
|
|
unsigned user_canceled : 1;
|
|
/* If this is set, the user can no longer cancel this request; we're
|
|
* just waiting for the free. */
|
|
unsigned request_done : 1;
|
|
};
|
|
|
|
/* Convert an evdns errors to the equivalent getaddrinfo error. */
|
|
static int
|
|
evdns_err_to_getaddrinfo_err(int e1)
|
|
{
|
|
/* XXX Do this better! */
|
|
if (e1 == DNS_ERR_NONE)
|
|
return 0;
|
|
else if (e1 == DNS_ERR_NOTEXIST)
|
|
return EVUTIL_EAI_NONAME;
|
|
else
|
|
return EVUTIL_EAI_FAIL;
|
|
}
|
|
|
|
/* Return the more informative of two getaddrinfo errors. */
|
|
static int
|
|
getaddrinfo_merge_err(int e1, int e2)
|
|
{
|
|
/* XXXX be cleverer here. */
|
|
if (e1 == 0)
|
|
return e2;
|
|
else
|
|
return e1;
|
|
}
|
|
|
|
static void
|
|
free_getaddrinfo_request(struct evdns_getaddrinfo_request *data)
|
|
{
|
|
/* DO NOT CALL this if either of the requests is pending. Only once
|
|
* both callbacks have been invoked is it safe to free the request */
|
|
if (data->pending_result)
|
|
evutil_freeaddrinfo(data->pending_result);
|
|
if (data->cname_result)
|
|
mm_free(data->cname_result);
|
|
event_del(&data->timeout);
|
|
mm_free(data);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
add_cname_to_reply(struct evdns_getaddrinfo_request *data,
|
|
struct evutil_addrinfo *ai)
|
|
{
|
|
if (data->cname_result && ai) {
|
|
ai->ai_canonname = data->cname_result;
|
|
data->cname_result = NULL;
|
|
}
|
|
}
|
|
|
|
/* Callback: invoked when one request in a mixed-format A/AAAA getaddrinfo
|
|
* request has finished, but the other one took too long to answer. Pass
|
|
* along the answer we got, and cancel the other request.
|
|
*/
|
|
static void
|
|
evdns_getaddrinfo_timeout_cb(evutil_socket_t fd, short what, void *ptr)
|
|
{
|
|
int v4_timedout = 0, v6_timedout = 0;
|
|
struct evdns_getaddrinfo_request *data = ptr;
|
|
|
|
/* Cancel any pending requests, and note which one */
|
|
if (data->ipv4_request.r) {
|
|
/* XXXX This does nothing if the request's callback is already
|
|
* running (pending_cb is set). */
|
|
evdns_cancel_request(NULL, data->ipv4_request.r);
|
|
v4_timedout = 1;
|
|
EVDNS_LOCK(data->evdns_base);
|
|
++data->evdns_base->getaddrinfo_ipv4_timeouts;
|
|
EVDNS_UNLOCK(data->evdns_base);
|
|
}
|
|
if (data->ipv6_request.r) {
|
|
/* XXXX This does nothing if the request's callback is already
|
|
* running (pending_cb is set). */
|
|
evdns_cancel_request(NULL, data->ipv6_request.r);
|
|
v6_timedout = 1;
|
|
EVDNS_LOCK(data->evdns_base);
|
|
++data->evdns_base->getaddrinfo_ipv6_timeouts;
|
|
EVDNS_UNLOCK(data->evdns_base);
|
|
}
|
|
|
|
/* We only use this timeout callback when we have an answer for
|
|
* one address. */
|
|
EVUTIL_ASSERT(!v4_timedout || !v6_timedout);
|
|
|
|
/* Report the outcome of the other request that didn't time out. */
|
|
if (data->pending_result) {
|
|
add_cname_to_reply(data, data->pending_result);
|
|
data->user_cb(0, data->pending_result, data->user_data);
|
|
data->pending_result = NULL;
|
|
} else {
|
|
int e = data->pending_error;
|
|
if (!e)
|
|
e = EVUTIL_EAI_AGAIN;
|
|
data->user_cb(e, NULL, data->user_data);
|
|
}
|
|
|
|
data->user_cb = NULL; /* prevent double-call if evdns callbacks are
|
|
* in-progress. XXXX It would be better if this
|
|
* weren't necessary. */
|
|
|
|
if (!v4_timedout && !v6_timedout) {
|
|
/* should be impossible? XXXX */
|
|
free_getaddrinfo_request(data);
|
|
}
|
|
}
|
|
|
|
static int
|
|
evdns_getaddrinfo_set_timeout(struct evdns_base *evdns_base,
|
|
struct evdns_getaddrinfo_request *data)
|
|
{
|
|
return event_add(&data->timeout, &evdns_base->global_getaddrinfo_allow_skew);
|
|
}
|
|
|
|
static inline int
|
|
evdns_result_is_answer(int result)
|
|
{
|
|
return (result != DNS_ERR_NOTIMPL && result != DNS_ERR_REFUSED &&
|
|
result != DNS_ERR_SERVERFAILED && result != DNS_ERR_CANCEL);
|
|
}
|
|
|
|
static void
|
|
evdns_getaddrinfo_gotresolve(int result, char type, int count,
|
|
int ttl, void *addresses, void *arg)
|
|
{
|
|
int i;
|
|
struct getaddrinfo_subrequest *req = arg;
|
|
struct getaddrinfo_subrequest *other_req;
|
|
struct evdns_getaddrinfo_request *data;
|
|
|
|
struct evutil_addrinfo *res;
|
|
|
|
struct sockaddr_in sin;
|
|
struct sockaddr_in6 sin6;
|
|
struct sockaddr *sa;
|
|
int socklen, addrlen;
|
|
void *addrp;
|
|
int err;
|
|
int user_canceled;
|
|
|
|
EVUTIL_ASSERT(req->type == DNS_IPv4_A || req->type == DNS_IPv6_AAAA);
|
|
if (req->type == DNS_IPv4_A) {
|
|
data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv4_request);
|
|
other_req = &data->ipv6_request;
|
|
} else {
|
|
data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv6_request);
|
|
other_req = &data->ipv4_request;
|
|
}
|
|
|
|
/** Called from evdns_base_free() with @fail_requests == 1 */
|
|
if (result != DNS_ERR_SHUTDOWN) {
|
|
EVDNS_LOCK(data->evdns_base);
|
|
if (evdns_result_is_answer(result)) {
|
|
if (req->type == DNS_IPv4_A)
|
|
++data->evdns_base->getaddrinfo_ipv4_answered;
|
|
else
|
|
++data->evdns_base->getaddrinfo_ipv6_answered;
|
|
}
|
|
user_canceled = data->user_canceled;
|
|
if (other_req->r == NULL)
|
|
data->request_done = 1;
|
|
EVDNS_UNLOCK(data->evdns_base);
|
|
} else {
|
|
data->evdns_base = NULL;
|
|
user_canceled = data->user_canceled;
|
|
}
|
|
|
|
req->r = NULL;
|
|
|
|
if (result == DNS_ERR_CANCEL && ! user_canceled) {
|
|
/* Internal cancel request from timeout or internal error.
|
|
* we already answered the user. */
|
|
if (other_req->r == NULL)
|
|
free_getaddrinfo_request(data);
|
|
return;
|
|
}
|
|
|
|
if (data->user_cb == NULL) {
|
|
/* We already answered. XXXX This shouldn't be needed; see
|
|
* comments in evdns_getaddrinfo_timeout_cb */
|
|
free_getaddrinfo_request(data);
|
|
return;
|
|
}
|
|
|
|
if (result == DNS_ERR_NONE) {
|
|
if (count == 0)
|
|
err = EVUTIL_EAI_NODATA;
|
|
else
|
|
err = 0;
|
|
} else {
|
|
err = evdns_err_to_getaddrinfo_err(result);
|
|
}
|
|
|
|
if (err) {
|
|
/* Looks like we got an error. */
|
|
if (other_req->r) {
|
|
/* The other request is still working; maybe it will
|
|
* succeed. */
|
|
/* XXXX handle failure from set_timeout */
|
|
if (result != DNS_ERR_SHUTDOWN) {
|
|
evdns_getaddrinfo_set_timeout(data->evdns_base, data);
|
|
}
|
|
data->pending_error = err;
|
|
return;
|
|
}
|
|
|
|
if (user_canceled) {
|
|
data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data);
|
|
} else if (data->pending_result) {
|
|
/* If we have an answer waiting, and we weren't
|
|
* canceled, ignore this error. */
|
|
add_cname_to_reply(data, data->pending_result);
|
|
data->user_cb(0, data->pending_result, data->user_data);
|
|
data->pending_result = NULL;
|
|
} else {
|
|
if (data->pending_error)
|
|
err = getaddrinfo_merge_err(err,
|
|
data->pending_error);
|
|
data->user_cb(err, NULL, data->user_data);
|
|
}
|
|
free_getaddrinfo_request(data);
|
|
return;
|
|
} else if (user_canceled) {
|
|
if (other_req->r) {
|
|
/* The other request is still working; let it hit this
|
|
* callback with EVUTIL_EAI_CANCEL callback and report
|
|
* the failure. */
|
|
return;
|
|
}
|
|
data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data);
|
|
free_getaddrinfo_request(data);
|
|
return;
|
|
}
|
|
|
|
/* Looks like we got some answers. We should turn them into addrinfos
|
|
* and then either queue those or return them all. */
|
|
EVUTIL_ASSERT(type == DNS_IPv4_A || type == DNS_IPv6_AAAA);
|
|
|
|
if (type == DNS_IPv4_A) {
|
|
memset(&sin, 0, sizeof(sin));
|
|
sin.sin_family = AF_INET;
|
|
sin.sin_port = htons(data->port);
|
|
|
|
sa = (struct sockaddr *)&sin;
|
|
socklen = sizeof(sin);
|
|
addrlen = 4;
|
|
addrp = &sin.sin_addr.s_addr;
|
|
} else {
|
|
memset(&sin6, 0, sizeof(sin6));
|
|
sin6.sin6_family = AF_INET6;
|
|
sin6.sin6_port = htons(data->port);
|
|
|
|
sa = (struct sockaddr *)&sin6;
|
|
socklen = sizeof(sin6);
|
|
addrlen = 16;
|
|
addrp = &sin6.sin6_addr.s6_addr;
|
|
}
|
|
|
|
res = NULL;
|
|
for (i=0; i < count; ++i) {
|
|
struct evutil_addrinfo *ai;
|
|
memcpy(addrp, ((char*)addresses)+i*addrlen, addrlen);
|
|
ai = evutil_new_addrinfo_(sa, socklen, &data->hints);
|
|
if (!ai) {
|
|
if (other_req->r) {
|
|
evdns_cancel_request(NULL, other_req->r);
|
|
}
|
|
data->user_cb(EVUTIL_EAI_MEMORY, NULL, data->user_data);
|
|
if (res)
|
|
evutil_freeaddrinfo(res);
|
|
|
|
if (other_req->r == NULL)
|
|
free_getaddrinfo_request(data);
|
|
return;
|
|
}
|
|
res = evutil_addrinfo_append_(res, ai);
|
|
}
|
|
|
|
if (other_req->r) {
|
|
/* The other request is still in progress; wait for it */
|
|
/* XXXX handle failure from set_timeout */
|
|
evdns_getaddrinfo_set_timeout(data->evdns_base, data);
|
|
data->pending_result = res;
|
|
return;
|
|
} else {
|
|
/* The other request is done or never started; append its
|
|
* results (if any) and return them. */
|
|
if (data->pending_result) {
|
|
if (req->type == DNS_IPv4_A)
|
|
res = evutil_addrinfo_append_(res,
|
|
data->pending_result);
|
|
else
|
|
res = evutil_addrinfo_append_(
|
|
data->pending_result, res);
|
|
data->pending_result = NULL;
|
|
}
|
|
|
|
/* Call the user callback. */
|
|
add_cname_to_reply(data, res);
|
|
data->user_cb(0, res, data->user_data);
|
|
|
|
/* Free data. */
|
|
free_getaddrinfo_request(data);
|
|
}
|
|
}
|
|
|
|
static struct hosts_entry *
|
|
find_hosts_entry(struct evdns_base *base, const char *hostname,
|
|
struct hosts_entry *find_after)
|
|
{
|
|
struct hosts_entry *e;
|
|
|
|
if (find_after)
|
|
e = TAILQ_NEXT(find_after, next);
|
|
else
|
|
e = TAILQ_FIRST(&base->hostsdb);
|
|
|
|
for (; e; e = TAILQ_NEXT(e, next)) {
|
|
if (!evutil_ascii_strcasecmp(e->hostname, hostname))
|
|
return e;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static int
|
|
evdns_getaddrinfo_fromhosts(struct evdns_base *base,
|
|
const char *nodename, struct evutil_addrinfo *hints, ev_uint16_t port,
|
|
struct evutil_addrinfo **res)
|
|
{
|
|
int n_found = 0;
|
|
struct hosts_entry *e;
|
|
struct evutil_addrinfo *ai=NULL;
|
|
int f = hints->ai_family;
|
|
|
|
EVDNS_LOCK(base);
|
|
for (e = find_hosts_entry(base, nodename, NULL); e;
|
|
e = find_hosts_entry(base, nodename, e)) {
|
|
struct evutil_addrinfo *ai_new;
|
|
++n_found;
|
|
if ((e->addr.sa.sa_family == AF_INET && f == PF_INET6) ||
|
|
(e->addr.sa.sa_family == AF_INET6 && f == PF_INET))
|
|
continue;
|
|
ai_new = evutil_new_addrinfo_(&e->addr.sa, e->addrlen, hints);
|
|
if (!ai_new) {
|
|
n_found = 0;
|
|
goto out;
|
|
}
|
|
sockaddr_setport(ai_new->ai_addr, port);
|
|
ai = evutil_addrinfo_append_(ai, ai_new);
|
|
}
|
|
EVDNS_UNLOCK(base);
|
|
out:
|
|
if (n_found) {
|
|
/* Note that we return an empty answer if we found entries for
|
|
* this hostname but none were of the right address type. */
|
|
*res = ai;
|
|
return 0;
|
|
} else {
|
|
if (ai)
|
|
evutil_freeaddrinfo(ai);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
struct evdns_getaddrinfo_request *
|
|
evdns_getaddrinfo(struct evdns_base *dns_base,
|
|
const char *nodename, const char *servname,
|
|
const struct evutil_addrinfo *hints_in,
|
|
evdns_getaddrinfo_cb cb, void *arg)
|
|
{
|
|
struct evdns_getaddrinfo_request *data;
|
|
struct evutil_addrinfo hints;
|
|
struct evutil_addrinfo *res = NULL;
|
|
int err;
|
|
int port = 0;
|
|
int want_cname = 0;
|
|
int started = 0;
|
|
|
|
if (!dns_base) {
|
|
dns_base = current_base;
|
|
if (!dns_base) {
|
|
log(EVDNS_LOG_WARN,
|
|
"Call to getaddrinfo_async with no "
|
|
"evdns_base configured.");
|
|
cb(EVUTIL_EAI_FAIL, NULL, arg); /* ??? better error? */
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
/* If we _must_ answer this immediately, do so. */
|
|
if ((hints_in && (hints_in->ai_flags & EVUTIL_AI_NUMERICHOST))) {
|
|
res = NULL;
|
|
err = evutil_getaddrinfo(nodename, servname, hints_in, &res);
|
|
cb(err, res, arg);
|
|
return NULL;
|
|
}
|
|
|
|
if (hints_in) {
|
|
memcpy(&hints, hints_in, sizeof(hints));
|
|
} else {
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = PF_UNSPEC;
|
|
}
|
|
|
|
evutil_adjust_hints_for_addrconfig_(&hints);
|
|
|
|
/* Now try to see if we _can_ answer immediately. */
|
|
/* (It would be nice to do this by calling getaddrinfo directly, with
|
|
* AI_NUMERICHOST, on plaforms that have it, but we can't: there isn't
|
|
* a reliable way to distinguish the "that wasn't a numeric host!" case
|
|
* from any other EAI_NONAME cases.) */
|
|
err = evutil_getaddrinfo_common_(nodename, servname, &hints, &res, &port);
|
|
if (err != EVUTIL_EAI_NEED_RESOLVE) {
|
|
cb(err, res, arg);
|
|
return NULL;
|
|
}
|
|
|
|
/* If there is an entry in the hosts file, we should give it now. */
|
|
if (!evdns_getaddrinfo_fromhosts(dns_base, nodename, &hints, port, &res)) {
|
|
cb(0, res, arg);
|
|
return NULL;
|
|
}
|
|
|
|
/* Okay, things are serious now. We're going to need to actually
|
|
* launch a request.
|
|
*/
|
|
data = mm_calloc(1,sizeof(struct evdns_getaddrinfo_request));
|
|
if (!data) {
|
|
cb(EVUTIL_EAI_MEMORY, NULL, arg);
|
|
return NULL;
|
|
}
|
|
|
|
memcpy(&data->hints, &hints, sizeof(data->hints));
|
|
data->port = (ev_uint16_t)port;
|
|
data->ipv4_request.type = DNS_IPv4_A;
|
|
data->ipv6_request.type = DNS_IPv6_AAAA;
|
|
data->user_cb = cb;
|
|
data->user_data = arg;
|
|
data->evdns_base = dns_base;
|
|
|
|
want_cname = (hints.ai_flags & EVUTIL_AI_CANONNAME);
|
|
|
|
/* If we are asked for a PF_UNSPEC address, we launch two requests in
|
|
* parallel: one for an A address and one for an AAAA address. We
|
|
* can't send just one request, since many servers only answer one
|
|
* question per DNS request.
|
|
*
|
|
* Once we have the answer to one request, we allow for a short
|
|
* timeout before we report it, to see if the other one arrives. If
|
|
* they both show up in time, then we report both the answers.
|
|
*
|
|
* If too many addresses of one type time out or fail, we should stop
|
|
* launching those requests. (XXX we don't do that yet.)
|
|
*/
|
|
|
|
EVDNS_LOCK(dns_base);
|
|
|
|
if (hints.ai_family != PF_INET6) {
|
|
log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv4 as %p",
|
|
nodename, &data->ipv4_request);
|
|
|
|
data->ipv4_request.r = evdns_base_resolve_ipv4(dns_base,
|
|
nodename, 0, evdns_getaddrinfo_gotresolve,
|
|
&data->ipv4_request);
|
|
if (want_cname && data->ipv4_request.r)
|
|
data->ipv4_request.r->current_req->put_cname_in_ptr =
|
|
&data->cname_result;
|
|
}
|
|
if (hints.ai_family != PF_INET) {
|
|
log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv6 as %p",
|
|
nodename, &data->ipv6_request);
|
|
|
|
data->ipv6_request.r = evdns_base_resolve_ipv6(dns_base,
|
|
nodename, 0, evdns_getaddrinfo_gotresolve,
|
|
&data->ipv6_request);
|
|
if (want_cname && data->ipv6_request.r)
|
|
data->ipv6_request.r->current_req->put_cname_in_ptr =
|
|
&data->cname_result;
|
|
}
|
|
|
|
evtimer_assign(&data->timeout, dns_base->event_base,
|
|
evdns_getaddrinfo_timeout_cb, data);
|
|
|
|
started = (data->ipv4_request.r || data->ipv6_request.r);
|
|
|
|
EVDNS_UNLOCK(dns_base);
|
|
|
|
if (started) {
|
|
return data;
|
|
} else {
|
|
mm_free(data);
|
|
cb(EVUTIL_EAI_FAIL, NULL, arg);
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
void
|
|
evdns_getaddrinfo_cancel(struct evdns_getaddrinfo_request *data)
|
|
{
|
|
EVDNS_LOCK(data->evdns_base);
|
|
if (data->request_done) {
|
|
EVDNS_UNLOCK(data->evdns_base);
|
|
return;
|
|
}
|
|
event_del(&data->timeout);
|
|
data->user_canceled = 1;
|
|
if (data->ipv4_request.r)
|
|
evdns_cancel_request(data->evdns_base, data->ipv4_request.r);
|
|
if (data->ipv6_request.r)
|
|
evdns_cancel_request(data->evdns_base, data->ipv6_request.r);
|
|
EVDNS_UNLOCK(data->evdns_base);
|
|
}
|