[337] | 1 | /***************************************************************************
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| 2 | * _ _ ____ _
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| 3 | * Project ___| | | | _ \| |
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| 4 | * / __| | | | |_) | |
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| 5 | * | (__| |_| | _ <| |___
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| 6 | * \___|\___/|_| \_\_____|
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| 7 | *
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| 8 | * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
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| 9 | *
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| 10 | * This software is licensed as described in the file COPYING, which
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| 11 | * you should have received as part of this distribution. The terms
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| 12 | * are also available at https://curl.haxx.se/docs/copyright.html.
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| 13 | *
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| 14 | * You may opt to use, copy, modify, merge, publish, distribute and/or sell
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| 15 | * copies of the Software, and permit persons to whom the Software is
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| 16 | * furnished to do so, under the terms of the COPYING file.
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| 17 | *
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| 18 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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| 19 | * KIND, either express or implied.
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| 20 | *
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| 21 | ***************************************************************************/
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| 22 |
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| 23 | #include "curl_setup.h"
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| 24 |
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| 25 | #ifdef HAVE_NETINET_IN_H
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| 26 | #include <netinet/in.h>
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| 27 | #endif
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| 28 | #ifdef HAVE_NETDB_H
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| 29 | #include <netdb.h>
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| 30 | #endif
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| 31 | #ifdef HAVE_ARPA_INET_H
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| 32 | #include <arpa/inet.h>
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| 33 | #endif
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| 34 | #ifdef __VMS
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| 35 | #include <in.h>
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| 36 | #include <inet.h>
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| 37 | #endif
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| 38 |
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| 39 | #ifdef HAVE_SETJMP_H
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| 40 | #include <setjmp.h>
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| 41 | #endif
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| 42 | #ifdef HAVE_SIGNAL_H
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| 43 | #include <signal.h>
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| 44 | #endif
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| 45 |
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| 46 | #ifdef HAVE_PROCESS_H
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| 47 | #include <process.h>
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| 48 | #endif
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| 49 |
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| 50 | #include "urldata.h"
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| 51 | #include "sendf.h"
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| 52 | #include "hostip.h"
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| 53 | #include "hash.h"
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| 54 | #include "share.h"
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| 55 | #include "strerror.h"
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| 56 | #include "url.h"
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| 57 | #include "inet_ntop.h"
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| 58 | #include "warnless.h"
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| 59 | /* The last 3 #include files should be in this order */
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| 60 | #include "curl_printf.h"
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| 61 | #include "curl_memory.h"
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| 62 | #include "memdebug.h"
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| 63 |
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| 64 | #if defined(CURLRES_SYNCH) && \
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| 65 | defined(HAVE_ALARM) && defined(SIGALRM) && defined(HAVE_SIGSETJMP)
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| 66 | /* alarm-based timeouts can only be used with all the dependencies satisfied */
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| 67 | #define USE_ALARM_TIMEOUT
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| 68 | #endif
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| 69 |
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| 70 | /*
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| 71 | * hostip.c explained
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| 72 | * ==================
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| 73 | *
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| 74 | * The main COMPILE-TIME DEFINES to keep in mind when reading the host*.c
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| 75 | * source file are these:
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| 76 | *
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| 77 | * CURLRES_IPV6 - this host has getaddrinfo() and family, and thus we use
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| 78 | * that. The host may not be able to resolve IPv6, but we don't really have to
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| 79 | * take that into account. Hosts that aren't IPv6-enabled have CURLRES_IPV4
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| 80 | * defined.
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| 81 | *
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| 82 | * CURLRES_ARES - is defined if libcurl is built to use c-ares for
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| 83 | * asynchronous name resolves. This can be Windows or *nix.
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| 84 | *
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| 85 | * CURLRES_THREADED - is defined if libcurl is built to run under (native)
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| 86 | * Windows, and then the name resolve will be done in a new thread, and the
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| 87 | * supported API will be the same as for ares-builds.
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| 88 | *
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| 89 | * If any of the two previous are defined, CURLRES_ASYNCH is defined too. If
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| 90 | * libcurl is not built to use an asynchronous resolver, CURLRES_SYNCH is
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| 91 | * defined.
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| 92 | *
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| 93 | * The host*.c sources files are split up like this:
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| 94 | *
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| 95 | * hostip.c - method-independent resolver functions and utility functions
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| 96 | * hostasyn.c - functions for asynchronous name resolves
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| 97 | * hostsyn.c - functions for synchronous name resolves
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| 98 | * hostip4.c - IPv4 specific functions
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| 99 | * hostip6.c - IPv6 specific functions
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| 100 | *
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| 101 | * The two asynchronous name resolver backends are implemented in:
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| 102 | * asyn-ares.c - functions for ares-using name resolves
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| 103 | * asyn-thread.c - functions for threaded name resolves
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| 104 |
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| 105 | * The hostip.h is the united header file for all this. It defines the
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| 106 | * CURLRES_* defines based on the config*.h and curl_setup.h defines.
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| 107 | */
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| 108 |
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| 109 | /* These two symbols are for the global DNS cache */
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| 110 | static struct curl_hash hostname_cache;
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| 111 | static int host_cache_initialized;
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| 112 |
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| 113 | static void freednsentry(void *freethis);
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| 114 |
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| 115 | /*
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| 116 | * Curl_global_host_cache_init() initializes and sets up a global DNS cache.
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| 117 | * Global DNS cache is general badness. Do not use. This will be removed in
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| 118 | * a future version. Use the share interface instead!
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| 119 | *
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| 120 | * Returns a struct curl_hash pointer on success, NULL on failure.
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| 121 | */
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| 122 | struct curl_hash *Curl_global_host_cache_init(void)
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| 123 | {
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| 124 | int rc = 0;
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| 125 | if(!host_cache_initialized) {
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| 126 | rc = Curl_hash_init(&hostname_cache, 7, Curl_hash_str,
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| 127 | Curl_str_key_compare, freednsentry);
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| 128 | if(!rc)
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| 129 | host_cache_initialized = 1;
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| 130 | }
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| 131 | return rc?NULL:&hostname_cache;
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| 132 | }
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| 133 |
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| 134 | /*
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| 135 | * Destroy and cleanup the global DNS cache
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| 136 | */
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| 137 | void Curl_global_host_cache_dtor(void)
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| 138 | {
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| 139 | if(host_cache_initialized) {
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| 140 | Curl_hash_destroy(&hostname_cache);
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| 141 | host_cache_initialized = 0;
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| 142 | }
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| 143 | }
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| 144 |
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| 145 | /*
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| 146 | * Return # of addresses in a Curl_addrinfo struct
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| 147 | */
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| 148 | int Curl_num_addresses(const Curl_addrinfo *addr)
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| 149 | {
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| 150 | int i = 0;
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| 151 | while(addr) {
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| 152 | addr = addr->ai_next;
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| 153 | i++;
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| 154 | }
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| 155 | return i;
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| 156 | }
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| 157 |
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| 158 | /*
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| 159 | * Curl_printable_address() returns a printable version of the 1st address
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| 160 | * given in the 'ai' argument. The result will be stored in the buf that is
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| 161 | * bufsize bytes big.
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| 162 | *
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| 163 | * If the conversion fails, it returns NULL.
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| 164 | */
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| 165 | const char *
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| 166 | Curl_printable_address(const Curl_addrinfo *ai, char *buf, size_t bufsize)
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| 167 | {
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| 168 | const struct sockaddr_in *sa4;
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| 169 | const struct in_addr *ipaddr4;
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| 170 | #ifdef ENABLE_IPV6
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| 171 | const struct sockaddr_in6 *sa6;
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| 172 | const struct in6_addr *ipaddr6;
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| 173 | #endif
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| 174 |
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| 175 | switch(ai->ai_family) {
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| 176 | case AF_INET:
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| 177 | sa4 = (const void *)ai->ai_addr;
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| 178 | ipaddr4 = &sa4->sin_addr;
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| 179 | return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr4, buf,
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| 180 | bufsize);
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| 181 | #ifdef ENABLE_IPV6
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| 182 | case AF_INET6:
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| 183 | sa6 = (const void *)ai->ai_addr;
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| 184 | ipaddr6 = &sa6->sin6_addr;
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| 185 | return Curl_inet_ntop(ai->ai_family, (const void *)ipaddr6, buf,
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| 186 | bufsize);
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| 187 | #endif
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| 188 | default:
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| 189 | break;
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| 190 | }
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| 191 | return NULL;
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| 192 | }
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| 193 |
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| 194 | /*
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| 195 | * Return a hostcache id string for the provided host + port, to be used by
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| 196 | * the DNS caching.
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| 197 | */
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| 198 | static char *
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| 199 | create_hostcache_id(const char *name, int port)
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| 200 | {
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| 201 | /* create and return the new allocated entry */
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| 202 | char *id = aprintf("%s:%d", name, port);
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| 203 | char *ptr = id;
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| 204 | if(ptr) {
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| 205 | /* lower case the name part */
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| 206 | while(*ptr && (*ptr != ':')) {
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| 207 | *ptr = (char)TOLOWER(*ptr);
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| 208 | ptr++;
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| 209 | }
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| 210 | }
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| 211 | return id;
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| 212 | }
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| 213 |
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| 214 | struct hostcache_prune_data {
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| 215 | long cache_timeout;
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| 216 | time_t now;
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| 217 | };
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| 218 |
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| 219 | /*
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| 220 | * This function is set as a callback to be called for every entry in the DNS
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| 221 | * cache when we want to prune old unused entries.
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| 222 | *
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| 223 | * Returning non-zero means remove the entry, return 0 to keep it in the
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| 224 | * cache.
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| 225 | */
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| 226 | static int
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| 227 | hostcache_timestamp_remove(void *datap, void *hc)
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| 228 | {
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| 229 | struct hostcache_prune_data *data =
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| 230 | (struct hostcache_prune_data *) datap;
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| 231 | struct Curl_dns_entry *c = (struct Curl_dns_entry *) hc;
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| 232 |
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| 233 | return (0 != c->timestamp)
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| 234 | && (data->now - c->timestamp >= data->cache_timeout);
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| 235 | }
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| 236 |
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| 237 | /*
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| 238 | * Prune the DNS cache. This assumes that a lock has already been taken.
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| 239 | */
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| 240 | static void
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| 241 | hostcache_prune(struct curl_hash *hostcache, long cache_timeout, time_t now)
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| 242 | {
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| 243 | struct hostcache_prune_data user;
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| 244 |
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| 245 | user.cache_timeout = cache_timeout;
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| 246 | user.now = now;
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| 247 |
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| 248 | Curl_hash_clean_with_criterium(hostcache,
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| 249 | (void *) &user,
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| 250 | hostcache_timestamp_remove);
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| 251 | }
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| 252 |
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| 253 | /*
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| 254 | * Library-wide function for pruning the DNS cache. This function takes and
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| 255 | * returns the appropriate locks.
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| 256 | */
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| 257 | void Curl_hostcache_prune(struct Curl_easy *data)
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| 258 | {
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| 259 | time_t now;
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| 260 |
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| 261 | if((data->set.dns_cache_timeout == -1) || !data->dns.hostcache)
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| 262 | /* cache forever means never prune, and NULL hostcache means
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| 263 | we can't do it */
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| 264 | return;
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| 265 |
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| 266 | if(data->share)
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| 267 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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| 268 |
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| 269 | time(&now);
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| 270 |
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| 271 | /* Remove outdated and unused entries from the hostcache */
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| 272 | hostcache_prune(data->dns.hostcache,
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| 273 | data->set.dns_cache_timeout,
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| 274 | now);
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| 275 |
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| 276 | if(data->share)
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| 277 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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| 278 | }
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| 279 |
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| 280 | #ifdef HAVE_SIGSETJMP
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| 281 | /* Beware this is a global and unique instance. This is used to store the
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| 282 | return address that we can jump back to from inside a signal handler. This
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| 283 | is not thread-safe stuff. */
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| 284 | sigjmp_buf curl_jmpenv;
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| 285 | #endif
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| 286 |
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| 287 | /* lookup address, returns entry if found and not stale */
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| 288 | static struct Curl_dns_entry *
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| 289 | fetch_addr(struct connectdata *conn,
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| 290 | const char *hostname,
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| 291 | int port)
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| 292 | {
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| 293 | char *entry_id = NULL;
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| 294 | struct Curl_dns_entry *dns = NULL;
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| 295 | size_t entry_len;
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| 296 | struct Curl_easy *data = conn->data;
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| 297 |
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| 298 | /* Create an entry id, based upon the hostname and port */
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| 299 | entry_id = create_hostcache_id(hostname, port);
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| 300 | /* If we can't create the entry id, fail */
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| 301 | if(!entry_id)
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| 302 | return dns;
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| 303 |
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| 304 | entry_len = strlen(entry_id);
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| 305 |
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| 306 | /* See if its already in our dns cache */
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| 307 | dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len + 1);
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| 308 |
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| 309 | if(dns && (data->set.dns_cache_timeout != -1)) {
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| 310 | /* See whether the returned entry is stale. Done before we release lock */
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| 311 | struct hostcache_prune_data user;
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| 312 |
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| 313 | time(&user.now);
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| 314 | user.cache_timeout = data->set.dns_cache_timeout;
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| 315 |
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| 316 | if(hostcache_timestamp_remove(&user, dns)) {
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| 317 | infof(data, "Hostname in DNS cache was stale, zapped\n");
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| 318 | dns = NULL; /* the memory deallocation is being handled by the hash */
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| 319 | Curl_hash_delete(data->dns.hostcache, entry_id, entry_len + 1);
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| 320 | }
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| 321 | }
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| 322 |
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| 323 | /* free the allocated entry_id again */
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| 324 | free(entry_id);
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| 325 |
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| 326 | return dns;
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| 327 | }
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| 328 |
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| 329 | /*
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| 330 | * Curl_fetch_addr() fetches a 'Curl_dns_entry' already in the DNS cache.
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| 331 | *
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| 332 | * Curl_resolv() checks initially and multi_runsingle() checks each time
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| 333 | * it discovers the handle in the state WAITRESOLVE whether the hostname
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| 334 | * has already been resolved and the address has already been stored in
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| 335 | * the DNS cache. This short circuits waiting for a lot of pending
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| 336 | * lookups for the same hostname requested by different handles.
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| 337 | *
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| 338 | * Returns the Curl_dns_entry entry pointer or NULL if not in the cache.
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| 339 | *
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| 340 | * The returned data *MUST* be "unlocked" with Curl_resolv_unlock() after
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| 341 | * use, or we'll leak memory!
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| 342 | */
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| 343 | struct Curl_dns_entry *
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| 344 | Curl_fetch_addr(struct connectdata *conn,
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| 345 | const char *hostname,
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| 346 | int port)
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| 347 | {
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| 348 | struct Curl_easy *data = conn->data;
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| 349 | struct Curl_dns_entry *dns = NULL;
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| 350 |
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| 351 | if(data->share)
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| 352 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
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| 353 |
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| 354 | dns = fetch_addr(conn, hostname, port);
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| 355 |
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| 356 | if(dns)
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| 357 | dns->inuse++; /* we use it! */
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| 358 |
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| 359 | if(data->share)
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| 360 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
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| 361 |
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| 362 | return dns;
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| 363 | }
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| 364 |
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| 365 | /*
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| 366 | * Curl_cache_addr() stores a 'Curl_addrinfo' struct in the DNS cache.
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| 367 | *
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| 368 | * When calling Curl_resolv() has resulted in a response with a returned
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| 369 | * address, we call this function to store the information in the dns
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| 370 | * cache etc
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| 371 | *
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| 372 | * Returns the Curl_dns_entry entry pointer or NULL if the storage failed.
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| 373 | */
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| 374 | struct Curl_dns_entry *
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| 375 | Curl_cache_addr(struct Curl_easy *data,
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| 376 | Curl_addrinfo *addr,
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| 377 | const char *hostname,
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| 378 | int port)
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| 379 | {
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| 380 | char *entry_id;
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| 381 | size_t entry_len;
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| 382 | struct Curl_dns_entry *dns;
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| 383 | struct Curl_dns_entry *dns2;
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| 384 |
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| 385 | /* Create an entry id, based upon the hostname and port */
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| 386 | entry_id = create_hostcache_id(hostname, port);
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| 387 | /* If we can't create the entry id, fail */
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| 388 | if(!entry_id)
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| 389 | return NULL;
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| 390 | entry_len = strlen(entry_id);
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| 391 |
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| 392 | /* Create a new cache entry */
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| 393 | dns = calloc(1, sizeof(struct Curl_dns_entry));
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| 394 | if(!dns) {
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| 395 | free(entry_id);
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| 396 | return NULL;
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| 397 | }
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| 398 |
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| 399 | dns->inuse = 1; /* the cache has the first reference */
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| 400 | dns->addr = addr; /* this is the address(es) */
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| 401 | time(&dns->timestamp);
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| 402 | if(dns->timestamp == 0)
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| 403 | dns->timestamp = 1; /* zero indicates CURLOPT_RESOLVE entry */
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| 404 |
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| 405 | /* Store the resolved data in our DNS cache. */
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| 406 | dns2 = Curl_hash_add(data->dns.hostcache, entry_id, entry_len + 1,
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| 407 | (void *)dns);
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| 408 | if(!dns2) {
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| 409 | free(dns);
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| 410 | free(entry_id);
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| 411 | return NULL;
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| 412 | }
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| 413 |
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| 414 | dns = dns2;
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| 415 | dns->inuse++; /* mark entry as in-use */
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| 416 |
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| 417 | /* free the allocated entry_id */
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| 418 | free(entry_id);
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| 419 |
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| 420 | return dns;
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| 421 | }
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| 422 |
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| 423 | /*
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| 424 | * Curl_resolv() is the main name resolve function within libcurl. It resolves
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| 425 | * a name and returns a pointer to the entry in the 'entry' argument (if one
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| 426 | * is provided). This function might return immediately if we're using asynch
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| 427 | * resolves. See the return codes.
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| 428 | *
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| 429 | * The cache entry we return will get its 'inuse' counter increased when this
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| 430 | * function is used. You MUST call Curl_resolv_unlock() later (when you're
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| 431 | * done using this struct) to decrease the counter again.
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| 432 | *
|
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| 433 | * In debug mode, we specifically test for an interface name "LocalHost"
|
---|
| 434 | * and resolve "localhost" instead as a means to permit test cases
|
---|
| 435 | * to connect to a local test server with any host name.
|
---|
| 436 | *
|
---|
| 437 | * Return codes:
|
---|
| 438 | *
|
---|
| 439 | * CURLRESOLV_ERROR (-1) = error, no pointer
|
---|
| 440 | * CURLRESOLV_RESOLVED (0) = OK, pointer provided
|
---|
| 441 | * CURLRESOLV_PENDING (1) = waiting for response, no pointer
|
---|
| 442 | */
|
---|
| 443 |
|
---|
| 444 | int Curl_resolv(struct connectdata *conn,
|
---|
| 445 | const char *hostname,
|
---|
| 446 | int port,
|
---|
| 447 | struct Curl_dns_entry **entry)
|
---|
| 448 | {
|
---|
| 449 | struct Curl_dns_entry *dns = NULL;
|
---|
| 450 | struct Curl_easy *data = conn->data;
|
---|
| 451 | CURLcode result;
|
---|
| 452 | int rc = CURLRESOLV_ERROR; /* default to failure */
|
---|
| 453 |
|
---|
| 454 | *entry = NULL;
|
---|
| 455 |
|
---|
| 456 | if(data->share)
|
---|
| 457 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 458 |
|
---|
| 459 | dns = fetch_addr(conn, hostname, port);
|
---|
| 460 |
|
---|
| 461 | if(dns) {
|
---|
| 462 | infof(data, "Hostname %s was found in DNS cache\n", hostname);
|
---|
| 463 | dns->inuse++; /* we use it! */
|
---|
| 464 | rc = CURLRESOLV_RESOLVED;
|
---|
| 465 | }
|
---|
| 466 |
|
---|
| 467 | if(data->share)
|
---|
| 468 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 469 |
|
---|
| 470 | if(!dns) {
|
---|
| 471 | /* The entry was not in the cache. Resolve it to IP address */
|
---|
| 472 |
|
---|
| 473 | Curl_addrinfo *addr;
|
---|
| 474 | int respwait;
|
---|
| 475 |
|
---|
| 476 | /* Check what IP specifics the app has requested and if we can provide it.
|
---|
| 477 | * If not, bail out. */
|
---|
| 478 | if(!Curl_ipvalid(conn))
|
---|
| 479 | return CURLRESOLV_ERROR;
|
---|
| 480 |
|
---|
| 481 | /* If Curl_getaddrinfo() returns NULL, 'respwait' might be set to a
|
---|
| 482 | non-zero value indicating that we need to wait for the response to the
|
---|
| 483 | resolve call */
|
---|
| 484 | addr = Curl_getaddrinfo(conn,
|
---|
| 485 | #ifdef DEBUGBUILD
|
---|
| 486 | (data->set.str[STRING_DEVICE]
|
---|
| 487 | && !strcmp(data->set.str[STRING_DEVICE],
|
---|
| 488 | "LocalHost"))?"localhost":
|
---|
| 489 | #endif
|
---|
| 490 | hostname, port, &respwait);
|
---|
| 491 |
|
---|
| 492 | if(!addr) {
|
---|
| 493 | if(respwait) {
|
---|
| 494 | /* the response to our resolve call will come asynchronously at
|
---|
| 495 | a later time, good or bad */
|
---|
| 496 | /* First, check that we haven't received the info by now */
|
---|
| 497 | result = Curl_resolver_is_resolved(conn, &dns);
|
---|
| 498 | if(result) /* error detected */
|
---|
| 499 | return CURLRESOLV_ERROR;
|
---|
| 500 | if(dns)
|
---|
| 501 | rc = CURLRESOLV_RESOLVED; /* pointer provided */
|
---|
| 502 | else
|
---|
| 503 | rc = CURLRESOLV_PENDING; /* no info yet */
|
---|
| 504 | }
|
---|
| 505 | }
|
---|
| 506 | else {
|
---|
| 507 | if(data->share)
|
---|
| 508 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 509 |
|
---|
| 510 | /* we got a response, store it in the cache */
|
---|
| 511 | dns = Curl_cache_addr(data, addr, hostname, port);
|
---|
| 512 |
|
---|
| 513 | if(data->share)
|
---|
| 514 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 515 |
|
---|
| 516 | if(!dns)
|
---|
| 517 | /* returned failure, bail out nicely */
|
---|
| 518 | Curl_freeaddrinfo(addr);
|
---|
| 519 | else
|
---|
| 520 | rc = CURLRESOLV_RESOLVED;
|
---|
| 521 | }
|
---|
| 522 | }
|
---|
| 523 |
|
---|
| 524 | *entry = dns;
|
---|
| 525 |
|
---|
| 526 | return rc;
|
---|
| 527 | }
|
---|
| 528 |
|
---|
| 529 | #ifdef USE_ALARM_TIMEOUT
|
---|
| 530 | /*
|
---|
| 531 | * This signal handler jumps back into the main libcurl code and continues
|
---|
| 532 | * execution. This effectively causes the remainder of the application to run
|
---|
| 533 | * within a signal handler which is nonportable and could lead to problems.
|
---|
| 534 | */
|
---|
| 535 | static
|
---|
| 536 | RETSIGTYPE alarmfunc(int sig)
|
---|
| 537 | {
|
---|
| 538 | /* this is for "-ansi -Wall -pedantic" to stop complaining! (rabe) */
|
---|
| 539 | (void)sig;
|
---|
| 540 | siglongjmp(curl_jmpenv, 1);
|
---|
| 541 | }
|
---|
| 542 | #endif /* USE_ALARM_TIMEOUT */
|
---|
| 543 |
|
---|
| 544 | /*
|
---|
| 545 | * Curl_resolv_timeout() is the same as Curl_resolv() but specifies a
|
---|
| 546 | * timeout. This function might return immediately if we're using asynch
|
---|
| 547 | * resolves. See the return codes.
|
---|
| 548 | *
|
---|
| 549 | * The cache entry we return will get its 'inuse' counter increased when this
|
---|
| 550 | * function is used. You MUST call Curl_resolv_unlock() later (when you're
|
---|
| 551 | * done using this struct) to decrease the counter again.
|
---|
| 552 | *
|
---|
| 553 | * If built with a synchronous resolver and use of signals is not
|
---|
| 554 | * disabled by the application, then a nonzero timeout will cause a
|
---|
| 555 | * timeout after the specified number of milliseconds. Otherwise, timeout
|
---|
| 556 | * is ignored.
|
---|
| 557 | *
|
---|
| 558 | * Return codes:
|
---|
| 559 | *
|
---|
| 560 | * CURLRESOLV_TIMEDOUT(-2) = warning, time too short or previous alarm expired
|
---|
| 561 | * CURLRESOLV_ERROR (-1) = error, no pointer
|
---|
| 562 | * CURLRESOLV_RESOLVED (0) = OK, pointer provided
|
---|
| 563 | * CURLRESOLV_PENDING (1) = waiting for response, no pointer
|
---|
| 564 | */
|
---|
| 565 |
|
---|
| 566 | int Curl_resolv_timeout(struct connectdata *conn,
|
---|
| 567 | const char *hostname,
|
---|
| 568 | int port,
|
---|
| 569 | struct Curl_dns_entry **entry,
|
---|
| 570 | time_t timeoutms)
|
---|
| 571 | {
|
---|
| 572 | #ifdef USE_ALARM_TIMEOUT
|
---|
| 573 | #ifdef HAVE_SIGACTION
|
---|
| 574 | struct sigaction keep_sigact; /* store the old struct here */
|
---|
| 575 | volatile bool keep_copysig = FALSE; /* whether old sigact has been saved */
|
---|
| 576 | struct sigaction sigact;
|
---|
| 577 | #else
|
---|
| 578 | #ifdef HAVE_SIGNAL
|
---|
| 579 | void (*keep_sigact)(int); /* store the old handler here */
|
---|
| 580 | #endif /* HAVE_SIGNAL */
|
---|
| 581 | #endif /* HAVE_SIGACTION */
|
---|
| 582 | volatile long timeout;
|
---|
| 583 | volatile unsigned int prev_alarm = 0;
|
---|
| 584 | struct Curl_easy *data = conn->data;
|
---|
| 585 | #endif /* USE_ALARM_TIMEOUT */
|
---|
| 586 | int rc;
|
---|
| 587 |
|
---|
| 588 | *entry = NULL;
|
---|
| 589 |
|
---|
| 590 | if(timeoutms < 0)
|
---|
| 591 | /* got an already expired timeout */
|
---|
| 592 | return CURLRESOLV_TIMEDOUT;
|
---|
| 593 |
|
---|
| 594 | #ifdef USE_ALARM_TIMEOUT
|
---|
| 595 | if(data->set.no_signal)
|
---|
| 596 | /* Ignore the timeout when signals are disabled */
|
---|
| 597 | timeout = 0;
|
---|
| 598 | else
|
---|
| 599 | timeout = (timeoutms > LONG_MAX) ? LONG_MAX : (long)timeoutms;
|
---|
| 600 |
|
---|
| 601 | if(!timeout)
|
---|
| 602 | /* USE_ALARM_TIMEOUT defined, but no timeout actually requested */
|
---|
| 603 | return Curl_resolv(conn, hostname, port, entry);
|
---|
| 604 |
|
---|
| 605 | if(timeout < 1000) {
|
---|
| 606 | /* The alarm() function only provides integer second resolution, so if
|
---|
| 607 | we want to wait less than one second we must bail out already now. */
|
---|
| 608 | failf(data,
|
---|
| 609 | "remaining timeout of %ld too small to resolve via SIGALRM method",
|
---|
| 610 | timeout);
|
---|
| 611 | return CURLRESOLV_TIMEDOUT;
|
---|
| 612 | }
|
---|
| 613 | /* This allows us to time-out from the name resolver, as the timeout
|
---|
| 614 | will generate a signal and we will siglongjmp() from that here.
|
---|
| 615 | This technique has problems (see alarmfunc).
|
---|
| 616 | This should be the last thing we do before calling Curl_resolv(),
|
---|
| 617 | as otherwise we'd have to worry about variables that get modified
|
---|
| 618 | before we invoke Curl_resolv() (and thus use "volatile"). */
|
---|
| 619 | if(sigsetjmp(curl_jmpenv, 1)) {
|
---|
| 620 | /* this is coming from a siglongjmp() after an alarm signal */
|
---|
| 621 | failf(data, "name lookup timed out");
|
---|
| 622 | rc = CURLRESOLV_ERROR;
|
---|
| 623 | goto clean_up;
|
---|
| 624 | }
|
---|
| 625 | else {
|
---|
| 626 | /*************************************************************
|
---|
| 627 | * Set signal handler to catch SIGALRM
|
---|
| 628 | * Store the old value to be able to set it back later!
|
---|
| 629 | *************************************************************/
|
---|
| 630 | #ifdef HAVE_SIGACTION
|
---|
| 631 | sigaction(SIGALRM, NULL, &sigact);
|
---|
| 632 | keep_sigact = sigact;
|
---|
| 633 | keep_copysig = TRUE; /* yes, we have a copy */
|
---|
| 634 | sigact.sa_handler = alarmfunc;
|
---|
| 635 | #ifdef SA_RESTART
|
---|
| 636 | /* HPUX doesn't have SA_RESTART but defaults to that behaviour! */
|
---|
| 637 | sigact.sa_flags &= ~SA_RESTART;
|
---|
| 638 | #endif
|
---|
| 639 | /* now set the new struct */
|
---|
| 640 | sigaction(SIGALRM, &sigact, NULL);
|
---|
| 641 | #else /* HAVE_SIGACTION */
|
---|
| 642 | /* no sigaction(), revert to the much lamer signal() */
|
---|
| 643 | #ifdef HAVE_SIGNAL
|
---|
| 644 | keep_sigact = signal(SIGALRM, alarmfunc);
|
---|
| 645 | #endif
|
---|
| 646 | #endif /* HAVE_SIGACTION */
|
---|
| 647 |
|
---|
| 648 | /* alarm() makes a signal get sent when the timeout fires off, and that
|
---|
| 649 | will abort system calls */
|
---|
| 650 | prev_alarm = alarm(curlx_sltoui(timeout/1000L));
|
---|
| 651 | }
|
---|
| 652 |
|
---|
| 653 | #else
|
---|
| 654 | #ifndef CURLRES_ASYNCH
|
---|
| 655 | if(timeoutms)
|
---|
| 656 | infof(conn->data, "timeout on name lookup is not supported\n");
|
---|
| 657 | #else
|
---|
| 658 | (void)timeoutms; /* timeoutms not used with an async resolver */
|
---|
| 659 | #endif
|
---|
| 660 | #endif /* USE_ALARM_TIMEOUT */
|
---|
| 661 |
|
---|
| 662 | /* Perform the actual name resolution. This might be interrupted by an
|
---|
| 663 | * alarm if it takes too long.
|
---|
| 664 | */
|
---|
| 665 | rc = Curl_resolv(conn, hostname, port, entry);
|
---|
| 666 |
|
---|
| 667 | #ifdef USE_ALARM_TIMEOUT
|
---|
| 668 | clean_up:
|
---|
| 669 |
|
---|
| 670 | if(!prev_alarm)
|
---|
| 671 | /* deactivate a possibly active alarm before uninstalling the handler */
|
---|
| 672 | alarm(0);
|
---|
| 673 |
|
---|
| 674 | #ifdef HAVE_SIGACTION
|
---|
| 675 | if(keep_copysig) {
|
---|
| 676 | /* we got a struct as it looked before, now put that one back nice
|
---|
| 677 | and clean */
|
---|
| 678 | sigaction(SIGALRM, &keep_sigact, NULL); /* put it back */
|
---|
| 679 | }
|
---|
| 680 | #else
|
---|
| 681 | #ifdef HAVE_SIGNAL
|
---|
| 682 | /* restore the previous SIGALRM handler */
|
---|
| 683 | signal(SIGALRM, keep_sigact);
|
---|
| 684 | #endif
|
---|
| 685 | #endif /* HAVE_SIGACTION */
|
---|
| 686 |
|
---|
| 687 | /* switch back the alarm() to either zero or to what it was before minus
|
---|
| 688 | the time we spent until now! */
|
---|
| 689 | if(prev_alarm) {
|
---|
| 690 | /* there was an alarm() set before us, now put it back */
|
---|
| 691 | timediff_t elapsed_secs = Curl_timediff(Curl_now(),
|
---|
| 692 | conn->created) / 1000;
|
---|
| 693 |
|
---|
| 694 | /* the alarm period is counted in even number of seconds */
|
---|
| 695 | unsigned long alarm_set = prev_alarm - elapsed_secs;
|
---|
| 696 |
|
---|
| 697 | if(!alarm_set ||
|
---|
| 698 | ((alarm_set >= 0x80000000) && (prev_alarm < 0x80000000)) ) {
|
---|
| 699 | /* if the alarm time-left reached zero or turned "negative" (counted
|
---|
| 700 | with unsigned values), we should fire off a SIGALRM here, but we
|
---|
| 701 | won't, and zero would be to switch it off so we never set it to
|
---|
| 702 | less than 1! */
|
---|
| 703 | alarm(1);
|
---|
| 704 | rc = CURLRESOLV_TIMEDOUT;
|
---|
| 705 | failf(data, "Previous alarm fired off!");
|
---|
| 706 | }
|
---|
| 707 | else
|
---|
| 708 | alarm((unsigned int)alarm_set);
|
---|
| 709 | }
|
---|
| 710 | #endif /* USE_ALARM_TIMEOUT */
|
---|
| 711 |
|
---|
| 712 | return rc;
|
---|
| 713 | }
|
---|
| 714 |
|
---|
| 715 | /*
|
---|
| 716 | * Curl_resolv_unlock() unlocks the given cached DNS entry. When this has been
|
---|
| 717 | * made, the struct may be destroyed due to pruning. It is important that only
|
---|
| 718 | * one unlock is made for each Curl_resolv() call.
|
---|
| 719 | *
|
---|
| 720 | * May be called with 'data' == NULL for global cache.
|
---|
| 721 | */
|
---|
| 722 | void Curl_resolv_unlock(struct Curl_easy *data, struct Curl_dns_entry *dns)
|
---|
| 723 | {
|
---|
| 724 | if(data && data->share)
|
---|
| 725 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 726 |
|
---|
| 727 | freednsentry(dns);
|
---|
| 728 |
|
---|
| 729 | if(data && data->share)
|
---|
| 730 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 731 | }
|
---|
| 732 |
|
---|
| 733 | /*
|
---|
| 734 | * File-internal: release cache dns entry reference, free if inuse drops to 0
|
---|
| 735 | */
|
---|
| 736 | static void freednsentry(void *freethis)
|
---|
| 737 | {
|
---|
| 738 | struct Curl_dns_entry *dns = (struct Curl_dns_entry *) freethis;
|
---|
| 739 | DEBUGASSERT(dns && (dns->inuse>0));
|
---|
| 740 |
|
---|
| 741 | dns->inuse--;
|
---|
| 742 | if(dns->inuse == 0) {
|
---|
| 743 | Curl_freeaddrinfo(dns->addr);
|
---|
| 744 | free(dns);
|
---|
| 745 | }
|
---|
| 746 | }
|
---|
| 747 |
|
---|
| 748 | /*
|
---|
| 749 | * Curl_mk_dnscache() inits a new DNS cache and returns success/failure.
|
---|
| 750 | */
|
---|
| 751 | int Curl_mk_dnscache(struct curl_hash *hash)
|
---|
| 752 | {
|
---|
| 753 | return Curl_hash_init(hash, 7, Curl_hash_str, Curl_str_key_compare,
|
---|
| 754 | freednsentry);
|
---|
| 755 | }
|
---|
| 756 |
|
---|
| 757 | /*
|
---|
| 758 | * Curl_hostcache_clean()
|
---|
| 759 | *
|
---|
| 760 | * This _can_ be called with 'data' == NULL but then of course no locking
|
---|
| 761 | * can be done!
|
---|
| 762 | */
|
---|
| 763 |
|
---|
| 764 | void Curl_hostcache_clean(struct Curl_easy *data,
|
---|
| 765 | struct curl_hash *hash)
|
---|
| 766 | {
|
---|
| 767 | if(data && data->share)
|
---|
| 768 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 769 |
|
---|
| 770 | Curl_hash_clean(hash);
|
---|
| 771 |
|
---|
| 772 | if(data && data->share)
|
---|
| 773 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 774 | }
|
---|
| 775 |
|
---|
| 776 |
|
---|
| 777 | CURLcode Curl_loadhostpairs(struct Curl_easy *data)
|
---|
| 778 | {
|
---|
| 779 | struct curl_slist *hostp;
|
---|
| 780 | char hostname[256];
|
---|
| 781 | int port;
|
---|
| 782 |
|
---|
| 783 | for(hostp = data->change.resolve; hostp; hostp = hostp->next) {
|
---|
| 784 | if(!hostp->data)
|
---|
| 785 | continue;
|
---|
| 786 | if(hostp->data[0] == '-') {
|
---|
| 787 | char *entry_id;
|
---|
| 788 | size_t entry_len;
|
---|
| 789 |
|
---|
| 790 | if(2 != sscanf(hostp->data + 1, "%255[^:]:%d", hostname, &port)) {
|
---|
| 791 | infof(data, "Couldn't parse CURLOPT_RESOLVE removal entry '%s'!\n",
|
---|
| 792 | hostp->data);
|
---|
| 793 | continue;
|
---|
| 794 | }
|
---|
| 795 |
|
---|
| 796 | /* Create an entry id, based upon the hostname and port */
|
---|
| 797 | entry_id = create_hostcache_id(hostname, port);
|
---|
| 798 | /* If we can't create the entry id, fail */
|
---|
| 799 | if(!entry_id) {
|
---|
| 800 | return CURLE_OUT_OF_MEMORY;
|
---|
| 801 | }
|
---|
| 802 |
|
---|
| 803 | entry_len = strlen(entry_id);
|
---|
| 804 |
|
---|
| 805 | if(data->share)
|
---|
| 806 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 807 |
|
---|
| 808 | /* delete entry, ignore if it didn't exist */
|
---|
| 809 | Curl_hash_delete(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
| 810 |
|
---|
| 811 | if(data->share)
|
---|
| 812 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 813 |
|
---|
| 814 | /* free the allocated entry_id again */
|
---|
| 815 | free(entry_id);
|
---|
| 816 | }
|
---|
| 817 | else {
|
---|
| 818 | struct Curl_dns_entry *dns;
|
---|
| 819 | Curl_addrinfo *addr;
|
---|
| 820 | char *entry_id;
|
---|
| 821 | size_t entry_len;
|
---|
| 822 | char buffer[256];
|
---|
| 823 | char *address = &buffer[0];
|
---|
| 824 |
|
---|
| 825 | if(3 != sscanf(hostp->data, "%255[^:]:%d:%255s", hostname, &port,
|
---|
| 826 | address)) {
|
---|
| 827 | infof(data, "Couldn't parse CURLOPT_RESOLVE entry '%s'!\n",
|
---|
| 828 | hostp->data);
|
---|
| 829 | continue;
|
---|
| 830 | }
|
---|
| 831 |
|
---|
| 832 | /* allow IP(v6) address within [brackets] */
|
---|
| 833 | if(address[0] == '[') {
|
---|
| 834 | size_t alen = strlen(address);
|
---|
| 835 | if(address[alen-1] != ']')
|
---|
| 836 | /* it needs to also end with ] to be valid */
|
---|
| 837 | continue;
|
---|
| 838 | address[alen-1] = 0; /* zero terminate there */
|
---|
| 839 | address++; /* pass the open bracket */
|
---|
| 840 | }
|
---|
| 841 |
|
---|
| 842 | addr = Curl_str2addr(address, port);
|
---|
| 843 | if(!addr) {
|
---|
| 844 | infof(data, "Address in '%s' found illegal!\n", hostp->data);
|
---|
| 845 | continue;
|
---|
| 846 | }
|
---|
| 847 |
|
---|
| 848 | /* Create an entry id, based upon the hostname and port */
|
---|
| 849 | entry_id = create_hostcache_id(hostname, port);
|
---|
| 850 | /* If we can't create the entry id, fail */
|
---|
| 851 | if(!entry_id) {
|
---|
| 852 | Curl_freeaddrinfo(addr);
|
---|
| 853 | return CURLE_OUT_OF_MEMORY;
|
---|
| 854 | }
|
---|
| 855 |
|
---|
| 856 | entry_len = strlen(entry_id);
|
---|
| 857 |
|
---|
| 858 | if(data->share)
|
---|
| 859 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
| 860 |
|
---|
| 861 | /* See if its already in our dns cache */
|
---|
| 862 | dns = Curl_hash_pick(data->dns.hostcache, entry_id, entry_len + 1);
|
---|
| 863 |
|
---|
| 864 | /* free the allocated entry_id again */
|
---|
| 865 | free(entry_id);
|
---|
| 866 |
|
---|
| 867 | if(!dns) {
|
---|
| 868 | /* if not in the cache already, put this host in the cache */
|
---|
| 869 | dns = Curl_cache_addr(data, addr, hostname, port);
|
---|
| 870 | if(dns) {
|
---|
| 871 | dns->timestamp = 0; /* mark as added by CURLOPT_RESOLVE */
|
---|
| 872 | /* release the returned reference; the cache itself will keep the
|
---|
| 873 | * entry alive: */
|
---|
| 874 | dns->inuse--;
|
---|
| 875 | }
|
---|
| 876 | }
|
---|
| 877 | else
|
---|
| 878 | /* this is a duplicate, free it again */
|
---|
| 879 | Curl_freeaddrinfo(addr);
|
---|
| 880 |
|
---|
| 881 | if(data->share)
|
---|
| 882 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
| 883 |
|
---|
| 884 | if(!dns) {
|
---|
| 885 | Curl_freeaddrinfo(addr);
|
---|
| 886 | return CURLE_OUT_OF_MEMORY;
|
---|
| 887 | }
|
---|
| 888 | infof(data, "Added %s:%d:%s to DNS cache\n",
|
---|
| 889 | hostname, port, address);
|
---|
| 890 | }
|
---|
| 891 | }
|
---|
| 892 | data->change.resolve = NULL; /* dealt with now */
|
---|
| 893 |
|
---|
| 894 | return CURLE_OK;
|
---|
| 895 | }
|
---|