1 | /**
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2 | * @file
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3 | * DNS - host name to IP address resolver.
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4 | *
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5 | * @defgroup dns DNS
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6 | * @ingroup callbackstyle_api
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7 | *
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8 | * Implements a DNS host name to IP address resolver.
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9 | *
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10 | * The lwIP DNS resolver functions are used to lookup a host name and
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11 | * map it to a numerical IP address. It maintains a list of resolved
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12 | * hostnames that can be queried with the dns_lookup() function.
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13 | * New hostnames can be resolved using the dns_query() function.
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14 | *
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15 | * The lwIP version of the resolver also adds a non-blocking version of
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16 | * gethostbyname() that will work with a raw API application. This function
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17 | * checks for an IP address string first and converts it if it is valid.
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18 | * gethostbyname() then does a dns_lookup() to see if the name is
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19 | * already in the table. If so, the IP is returned. If not, a query is
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20 | * issued and the function returns with a ERR_INPROGRESS status. The app
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21 | * using the dns client must then go into a waiting state.
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22 | *
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23 | * Once a hostname has been resolved (or found to be non-existent),
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24 | * the resolver code calls a specified callback function (which
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25 | * must be implemented by the module that uses the resolver).
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26 | *
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27 | * Multicast DNS queries are supported for names ending on ".local".
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28 | * However, only "One-Shot Multicast DNS Queries" are supported (RFC 6762
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29 | * chapter 5.1), this is not a fully compliant implementation of continuous
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30 | * mDNS querying!
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31 | *
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32 | * All functions must be called from TCPIP thread.
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33 | *
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34 | * @see DNS_MAX_SERVERS
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35 | * @see LWIP_DHCP_MAX_DNS_SERVERS
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36 | * @see @ref netconn_common for thread-safe access.
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37 | */
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38 |
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39 | /*
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40 | * Port to lwIP from uIP
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41 | * by Jim Pettinato April 2007
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42 | *
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43 | * security fixes and more by Simon Goldschmidt
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44 | *
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45 | * uIP version Copyright (c) 2002-2003, Adam Dunkels.
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46 | * All rights reserved.
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47 | *
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48 | * Redistribution and use in source and binary forms, with or without
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49 | * modification, are permitted provided that the following conditions
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50 | * are met:
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51 | * 1. Redistributions of source code must retain the above copyright
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52 | * notice, this list of conditions and the following disclaimer.
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53 | * 2. Redistributions in binary form must reproduce the above copyright
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54 | * notice, this list of conditions and the following disclaimer in the
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55 | * documentation and/or other materials provided with the distribution.
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56 | * 3. The name of the author may not be used to endorse or promote
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57 | * products derived from this software without specific prior
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58 | * written permission.
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59 | *
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60 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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61 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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62 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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63 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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64 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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65 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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66 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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67 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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68 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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69 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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70 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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71 | */
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72 |
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73 | /*-----------------------------------------------------------------------------
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74 | * RFC 1035 - Domain names - implementation and specification
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75 | * RFC 2181 - Clarifications to the DNS Specification
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76 | *----------------------------------------------------------------------------*/
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77 |
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78 | /** @todo: define good default values (rfc compliance) */
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79 | /** @todo: improve answer parsing, more checkings... */
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80 | /** @todo: check RFC1035 - 7.3. Processing responses */
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81 | /** @todo: one-shot mDNS: dual-stack fallback to another IP version */
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82 |
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83 | /*-----------------------------------------------------------------------------
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84 | * Includes
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85 | *----------------------------------------------------------------------------*/
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86 |
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87 | #include "lwip/opt.h"
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88 |
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89 | #if LWIP_DNS /* don't build if not configured for use in lwipopts.h */
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90 |
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91 | #include "lwip/def.h"
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92 | #include "lwip/udp.h"
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93 | #include "lwip/mem.h"
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94 | #include "lwip/memp.h"
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95 | #include "lwip/dns.h"
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96 | #include "lwip/prot/dns.h"
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97 |
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98 | #include <string.h>
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99 |
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100 | /** Random generator function to create random TXIDs and source ports for queries */
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101 | #ifndef DNS_RAND_TXID
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102 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_XID) != 0)
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103 | #define DNS_RAND_TXID LWIP_RAND
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104 | #else
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105 | static u16_t dns_txid;
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106 | #define DNS_RAND_TXID() (++dns_txid)
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107 | #endif
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108 | #endif
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109 |
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110 | /** Limits the source port to be >= 1024 by default */
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111 | #ifndef DNS_PORT_ALLOWED
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112 | #define DNS_PORT_ALLOWED(port) ((port) >= 1024)
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113 | #endif
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114 |
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115 | /** DNS resource record max. TTL (one week as default) */
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116 | #ifndef DNS_MAX_TTL
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117 | #define DNS_MAX_TTL 604800
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118 | #elif DNS_MAX_TTL > 0x7FFFFFFF
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119 | #error DNS_MAX_TTL must be a positive 32-bit value
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120 | #endif
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121 |
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122 | #if DNS_TABLE_SIZE > 255
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123 | #error DNS_TABLE_SIZE must fit into an u8_t
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124 | #endif
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125 | #if DNS_MAX_SERVERS > 255
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126 | #error DNS_MAX_SERVERS must fit into an u8_t
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127 | #endif
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128 |
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129 | /* The number of parallel requests (i.e. calls to dns_gethostbyname
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130 | * that cannot be answered from the DNS table.
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131 | * This is set to the table size by default.
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132 | */
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133 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
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134 | #ifndef DNS_MAX_REQUESTS
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135 | #define DNS_MAX_REQUESTS DNS_TABLE_SIZE
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136 | #else
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137 | #if DNS_MAX_REQUESTS > 255
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138 | #error DNS_MAX_REQUESTS must fit into an u8_t
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139 | #endif
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140 | #endif
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141 | #else
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142 | /* In this configuration, both arrays have to have the same size and are used
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143 | * like one entry (used/free) */
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144 | #define DNS_MAX_REQUESTS DNS_TABLE_SIZE
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145 | #endif
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146 |
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147 | /* The number of UDP source ports used in parallel */
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148 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
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149 | #ifndef DNS_MAX_SOURCE_PORTS
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150 | #define DNS_MAX_SOURCE_PORTS DNS_MAX_REQUESTS
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151 | #else
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152 | #if DNS_MAX_SOURCE_PORTS > 255
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153 | #error DNS_MAX_SOURCE_PORTS must fit into an u8_t
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154 | #endif
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155 | #endif
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156 | #else
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157 | #ifdef DNS_MAX_SOURCE_PORTS
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158 | #undef DNS_MAX_SOURCE_PORTS
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159 | #endif
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160 | #define DNS_MAX_SOURCE_PORTS 1
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161 | #endif
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162 |
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163 | #if LWIP_IPV4 && LWIP_IPV6
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164 | #define LWIP_DNS_ADDRTYPE_IS_IPV6(t) (((t) == LWIP_DNS_ADDRTYPE_IPV6_IPV4) || ((t) == LWIP_DNS_ADDRTYPE_IPV6))
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165 | #define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) (IP_IS_V6_VAL(ip) ? LWIP_DNS_ADDRTYPE_IS_IPV6(t) : (!LWIP_DNS_ADDRTYPE_IS_IPV6(t)))
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166 | #define LWIP_DNS_ADDRTYPE_ARG(x) , x
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167 | #define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) x
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168 | #define LWIP_DNS_SET_ADDRTYPE(x, y) do { x = y; } while(0)
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169 | #else
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170 | #if LWIP_IPV6
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171 | #define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 1
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172 | #else
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173 | #define LWIP_DNS_ADDRTYPE_IS_IPV6(t) 0
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174 | #endif
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175 | #define LWIP_DNS_ADDRTYPE_MATCH_IP(t, ip) 1
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176 | #define LWIP_DNS_ADDRTYPE_ARG(x)
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177 | #define LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(x) 0
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178 | #define LWIP_DNS_SET_ADDRTYPE(x, y)
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179 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
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180 |
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181 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
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182 | #define LWIP_DNS_ISMDNS_ARG(x) , x
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183 | #else
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184 | #define LWIP_DNS_ISMDNS_ARG(x)
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185 | #endif
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186 |
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187 | /** DNS query message structure.
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188 | No packing needed: only used locally on the stack. */
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189 | struct dns_query {
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190 | /* DNS query record starts with either a domain name or a pointer
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191 | to a name already present somewhere in the packet. */
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192 | u16_t type;
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193 | u16_t cls;
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194 | };
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195 | #define SIZEOF_DNS_QUERY 4
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196 |
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197 | /** DNS answer message structure.
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198 | No packing needed: only used locally on the stack. */
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199 | struct dns_answer {
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200 | /* DNS answer record starts with either a domain name or a pointer
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201 | to a name already present somewhere in the packet. */
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202 | u16_t type;
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203 | u16_t cls;
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204 | u32_t ttl;
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205 | u16_t len;
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206 | };
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207 | #define SIZEOF_DNS_ANSWER 10
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208 | /* maximum allowed size for the struct due to non-packed */
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209 | #define SIZEOF_DNS_ANSWER_ASSERT 12
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210 |
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211 | /* DNS table entry states */
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212 | typedef enum {
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213 | DNS_STATE_UNUSED = 0,
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214 | DNS_STATE_NEW = 1,
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215 | DNS_STATE_ASKING = 2,
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216 | DNS_STATE_DONE = 3
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217 | } dns_state_enum_t;
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218 |
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219 | /** DNS table entry */
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220 | struct dns_table_entry {
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221 | u32_t ttl;
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222 | ip_addr_t ipaddr;
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223 | u16_t txid;
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224 | u8_t state;
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225 | u8_t server_idx;
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226 | u8_t tmr;
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227 | u8_t retries;
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228 | u8_t seqno;
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229 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
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230 | u8_t pcb_idx;
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231 | #endif
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232 | char name[DNS_MAX_NAME_LENGTH];
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233 | #if LWIP_IPV4 && LWIP_IPV6
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234 | u8_t reqaddrtype;
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235 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
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236 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
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237 | u8_t is_mdns;
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238 | #endif
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239 | };
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240 |
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241 | /** DNS request table entry: used when dns_gehostbyname cannot answer the
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242 | * request from the DNS table */
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243 | struct dns_req_entry {
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244 | /* pointer to callback on DNS query done */
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245 | dns_found_callback found;
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246 | /* argument passed to the callback function */
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247 | void *arg;
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248 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
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249 | u8_t dns_table_idx;
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250 | #endif
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251 | #if LWIP_IPV4 && LWIP_IPV6
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252 | u8_t reqaddrtype;
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253 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
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254 | };
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255 |
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256 | #if DNS_LOCAL_HOSTLIST
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257 |
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258 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
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259 | /** Local host-list. For hostnames in this list, no
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260 | * external name resolution is performed */
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261 | static struct local_hostlist_entry *local_hostlist_dynamic;
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262 | #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
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263 |
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264 | /** Defining this allows the local_hostlist_static to be placed in a different
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265 | * linker section (e.g. FLASH) */
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266 | #ifndef DNS_LOCAL_HOSTLIST_STORAGE_PRE
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267 | #define DNS_LOCAL_HOSTLIST_STORAGE_PRE static
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268 | #endif /* DNS_LOCAL_HOSTLIST_STORAGE_PRE */
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269 | /** Defining this allows the local_hostlist_static to be placed in a different
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270 | * linker section (e.g. FLASH) */
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271 | #ifndef DNS_LOCAL_HOSTLIST_STORAGE_POST
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272 | #define DNS_LOCAL_HOSTLIST_STORAGE_POST
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273 | #endif /* DNS_LOCAL_HOSTLIST_STORAGE_POST */
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274 | DNS_LOCAL_HOSTLIST_STORAGE_PRE struct local_hostlist_entry local_hostlist_static[]
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275 | DNS_LOCAL_HOSTLIST_STORAGE_POST = DNS_LOCAL_HOSTLIST_INIT;
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276 |
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277 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
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278 |
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279 | static void dns_init_local(void);
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280 | static err_t dns_lookup_local(const char *hostname, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype));
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281 | #endif /* DNS_LOCAL_HOSTLIST */
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282 |
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283 |
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284 | /* forward declarations */
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285 | static void dns_recv(void *s, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port);
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286 | static void dns_check_entries(void);
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287 | static void dns_call_found(u8_t idx, ip_addr_t *addr);
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288 |
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289 | /*-----------------------------------------------------------------------------
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290 | * Globals
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291 | *----------------------------------------------------------------------------*/
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292 |
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293 | /* DNS variables */
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294 | static struct udp_pcb *dns_pcbs[DNS_MAX_SOURCE_PORTS];
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295 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
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296 | static u8_t dns_last_pcb_idx;
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297 | #endif
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298 | static u8_t dns_seqno;
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299 | static struct dns_table_entry dns_table[DNS_TABLE_SIZE];
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300 | static struct dns_req_entry dns_requests[DNS_MAX_REQUESTS];
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301 | static ip_addr_t dns_servers[DNS_MAX_SERVERS];
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302 |
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303 | #if LWIP_IPV4
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304 | const ip_addr_t dns_mquery_v4group = DNS_MQUERY_IPV4_GROUP_INIT;
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305 | #endif /* LWIP_IPV4 */
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306 | #if LWIP_IPV6
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307 | const ip_addr_t dns_mquery_v6group = DNS_MQUERY_IPV6_GROUP_INIT;
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308 | #endif /* LWIP_IPV6 */
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309 |
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310 | /**
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311 | * Initialize the resolver: set up the UDP pcb and configure the default server
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312 | * (if DNS_SERVER_ADDRESS is set).
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313 | */
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314 | void
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315 | dns_init(void)
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316 | {
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317 | #ifdef DNS_SERVER_ADDRESS
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318 | /* initialize default DNS server address */
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319 | ip_addr_t dnsserver;
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320 | DNS_SERVER_ADDRESS(&dnsserver);
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321 | dns_setserver(0, &dnsserver);
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322 | #endif /* DNS_SERVER_ADDRESS */
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323 |
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324 | LWIP_ASSERT("sanity check SIZEOF_DNS_QUERY",
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325 | sizeof(struct dns_query) == SIZEOF_DNS_QUERY);
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326 | LWIP_ASSERT("sanity check SIZEOF_DNS_ANSWER",
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327 | sizeof(struct dns_answer) <= SIZEOF_DNS_ANSWER_ASSERT);
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328 |
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329 | LWIP_DEBUGF(DNS_DEBUG, ("dns_init: initializing\n"));
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330 |
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331 | /* if dns client not yet initialized... */
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332 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0)
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333 | if (dns_pcbs[0] == NULL) {
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334 | dns_pcbs[0] = udp_new_ip_type(IPADDR_TYPE_ANY);
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335 | LWIP_ASSERT("dns_pcbs[0] != NULL", dns_pcbs[0] != NULL);
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336 |
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337 | /* initialize DNS table not needed (initialized to zero since it is a
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338 | * global variable) */
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339 | LWIP_ASSERT("For implicit initialization to work, DNS_STATE_UNUSED needs to be 0",
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340 | DNS_STATE_UNUSED == 0);
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341 |
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342 | /* initialize DNS client */
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343 | udp_bind(dns_pcbs[0], IP_ANY_TYPE, 0);
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344 | udp_recv(dns_pcbs[0], dns_recv, NULL);
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345 | }
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346 | #endif
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347 |
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348 | #if DNS_LOCAL_HOSTLIST
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349 | dns_init_local();
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350 | #endif
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351 | }
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352 |
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353 | /**
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354 | * @ingroup dns
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355 | * Initialize one of the DNS servers.
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356 | *
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357 | * @param numdns the index of the DNS server to set must be < DNS_MAX_SERVERS
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358 | * @param dnsserver IP address of the DNS server to set
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359 | */
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360 | void
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361 | dns_setserver(u8_t numdns, const ip_addr_t *dnsserver)
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362 | {
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363 | if (numdns < DNS_MAX_SERVERS) {
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364 | if (dnsserver != NULL) {
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365 | dns_servers[numdns] = (*dnsserver);
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366 | } else {
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367 | dns_servers[numdns] = *IP_ADDR_ANY;
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368 | }
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369 | }
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370 | }
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371 |
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372 | /**
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373 | * @ingroup dns
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374 | * Obtain one of the currently configured DNS server.
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375 | *
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376 | * @param numdns the index of the DNS server
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377 | * @return IP address of the indexed DNS server or "ip_addr_any" if the DNS
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378 | * server has not been configured.
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379 | */
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380 | const ip_addr_t *
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381 | dns_getserver(u8_t numdns)
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382 | {
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383 | if (numdns < DNS_MAX_SERVERS) {
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384 | return &dns_servers[numdns];
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385 | } else {
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386 | return IP_ADDR_ANY;
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387 | }
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388 | }
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389 |
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390 | /**
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391 | * The DNS resolver client timer - handle retries and timeouts and should
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392 | * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
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393 | */
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394 | void
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395 | dns_tmr(void)
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396 | {
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397 | LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
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398 | dns_check_entries();
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399 | }
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400 |
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401 | #if DNS_LOCAL_HOSTLIST
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402 | static void
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403 | dns_init_local(void)
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404 | {
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405 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT)
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406 | size_t i;
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407 | struct local_hostlist_entry *entry;
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408 | /* Dynamic: copy entries from DNS_LOCAL_HOSTLIST_INIT to list */
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409 | struct local_hostlist_entry local_hostlist_init[] = DNS_LOCAL_HOSTLIST_INIT;
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410 | size_t namelen;
|
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411 | for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_init); i++) {
|
---|
412 | struct local_hostlist_entry *init_entry = &local_hostlist_init[i];
|
---|
413 | LWIP_ASSERT("invalid host name (NULL)", init_entry->name != NULL);
|
---|
414 | namelen = strlen(init_entry->name);
|
---|
415 | LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
|
---|
416 | entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
|
---|
417 | LWIP_ASSERT("mem-error in dns_init_local", entry != NULL);
|
---|
418 | if (entry != NULL) {
|
---|
419 | char *entry_name = (char *)entry + sizeof(struct local_hostlist_entry);
|
---|
420 | MEMCPY(entry_name, init_entry->name, namelen);
|
---|
421 | entry_name[namelen] = 0;
|
---|
422 | entry->name = entry_name;
|
---|
423 | entry->addr = init_entry->addr;
|
---|
424 | entry->next = local_hostlist_dynamic;
|
---|
425 | local_hostlist_dynamic = entry;
|
---|
426 | }
|
---|
427 | }
|
---|
428 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC && defined(DNS_LOCAL_HOSTLIST_INIT) */
|
---|
429 | }
|
---|
430 |
|
---|
431 | /**
|
---|
432 | * @ingroup dns
|
---|
433 | * Iterate the local host-list for a hostname.
|
---|
434 | *
|
---|
435 | * @param iterator_fn a function that is called for every entry in the local host-list
|
---|
436 | * @param iterator_arg 3rd argument passed to iterator_fn
|
---|
437 | * @return the number of entries in the local host-list
|
---|
438 | */
|
---|
439 | size_t
|
---|
440 | dns_local_iterate(dns_found_callback iterator_fn, void *iterator_arg)
|
---|
441 | {
|
---|
442 | size_t i;
|
---|
443 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
|
---|
444 | struct local_hostlist_entry *entry = local_hostlist_dynamic;
|
---|
445 | i = 0;
|
---|
446 | while (entry != NULL) {
|
---|
447 | if (iterator_fn != NULL) {
|
---|
448 | iterator_fn(entry->name, &entry->addr, iterator_arg);
|
---|
449 | }
|
---|
450 | i++;
|
---|
451 | entry = entry->next;
|
---|
452 | }
|
---|
453 | #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
|
---|
454 | for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_static); i++) {
|
---|
455 | if (iterator_fn != NULL) {
|
---|
456 | iterator_fn(local_hostlist_static[i].name, &local_hostlist_static[i].addr, iterator_arg);
|
---|
457 | }
|
---|
458 | }
|
---|
459 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
|
---|
460 | return i;
|
---|
461 | }
|
---|
462 |
|
---|
463 | /**
|
---|
464 | * @ingroup dns
|
---|
465 | * Scans the local host-list for a hostname.
|
---|
466 | *
|
---|
467 | * @param hostname Hostname to look for in the local host-list
|
---|
468 | * @param addr the first IP address for the hostname in the local host-list or
|
---|
469 | * IPADDR_NONE if not found.
|
---|
470 | * @param dns_addrtype - LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 (ATTENTION: no fallback here!)
|
---|
471 | * - LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 (ATTENTION: no fallback here!)
|
---|
472 | * - LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only
|
---|
473 | * - LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only
|
---|
474 | * @return ERR_OK if found, ERR_ARG if not found
|
---|
475 | */
|
---|
476 | err_t
|
---|
477 | dns_local_lookup(const char *hostname, ip_addr_t *addr, u8_t dns_addrtype)
|
---|
478 | {
|
---|
479 | LWIP_UNUSED_ARG(dns_addrtype);
|
---|
480 | return dns_lookup_local(hostname, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype));
|
---|
481 | }
|
---|
482 |
|
---|
483 | /* Internal implementation for dns_local_lookup and dns_lookup */
|
---|
484 | static err_t
|
---|
485 | dns_lookup_local(const char *hostname, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype))
|
---|
486 | {
|
---|
487 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
|
---|
488 | struct local_hostlist_entry *entry = local_hostlist_dynamic;
|
---|
489 | while (entry != NULL) {
|
---|
490 | if ((lwip_stricmp(entry->name, hostname) == 0) &&
|
---|
491 | LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, entry->addr)) {
|
---|
492 | if (addr) {
|
---|
493 | ip_addr_copy(*addr, entry->addr);
|
---|
494 | }
|
---|
495 | return ERR_OK;
|
---|
496 | }
|
---|
497 | entry = entry->next;
|
---|
498 | }
|
---|
499 | #else /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
|
---|
500 | size_t i;
|
---|
501 | for (i = 0; i < LWIP_ARRAYSIZE(local_hostlist_static); i++) {
|
---|
502 | if ((lwip_stricmp(local_hostlist_static[i].name, hostname) == 0) &&
|
---|
503 | LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, local_hostlist_static[i].addr)) {
|
---|
504 | if (addr) {
|
---|
505 | ip_addr_copy(*addr, local_hostlist_static[i].addr);
|
---|
506 | }
|
---|
507 | return ERR_OK;
|
---|
508 | }
|
---|
509 | }
|
---|
510 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
|
---|
511 | return ERR_ARG;
|
---|
512 | }
|
---|
513 |
|
---|
514 | #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
|
---|
515 | /**
|
---|
516 | * @ingroup dns
|
---|
517 | * Remove all entries from the local host-list for a specific hostname
|
---|
518 | * and/or IP address
|
---|
519 | *
|
---|
520 | * @param hostname hostname for which entries shall be removed from the local
|
---|
521 | * host-list
|
---|
522 | * @param addr address for which entries shall be removed from the local host-list
|
---|
523 | * @return the number of removed entries
|
---|
524 | */
|
---|
525 | int
|
---|
526 | dns_local_removehost(const char *hostname, const ip_addr_t *addr)
|
---|
527 | {
|
---|
528 | int removed = 0;
|
---|
529 | struct local_hostlist_entry *entry = local_hostlist_dynamic;
|
---|
530 | struct local_hostlist_entry *last_entry = NULL;
|
---|
531 | while (entry != NULL) {
|
---|
532 | if (((hostname == NULL) || !lwip_stricmp(entry->name, hostname)) &&
|
---|
533 | ((addr == NULL) || ip_addr_cmp(&entry->addr, addr))) {
|
---|
534 | struct local_hostlist_entry *free_entry;
|
---|
535 | if (last_entry != NULL) {
|
---|
536 | last_entry->next = entry->next;
|
---|
537 | } else {
|
---|
538 | local_hostlist_dynamic = entry->next;
|
---|
539 | }
|
---|
540 | free_entry = entry;
|
---|
541 | entry = entry->next;
|
---|
542 | memp_free(MEMP_LOCALHOSTLIST, free_entry);
|
---|
543 | removed++;
|
---|
544 | } else {
|
---|
545 | last_entry = entry;
|
---|
546 | entry = entry->next;
|
---|
547 | }
|
---|
548 | }
|
---|
549 | return removed;
|
---|
550 | }
|
---|
551 |
|
---|
552 | /**
|
---|
553 | * @ingroup dns
|
---|
554 | * Add a hostname/IP address pair to the local host-list.
|
---|
555 | * Duplicates are not checked.
|
---|
556 | *
|
---|
557 | * @param hostname hostname of the new entry
|
---|
558 | * @param addr IP address of the new entry
|
---|
559 | * @return ERR_OK if succeeded or ERR_MEM on memory error
|
---|
560 | */
|
---|
561 | err_t
|
---|
562 | dns_local_addhost(const char *hostname, const ip_addr_t *addr)
|
---|
563 | {
|
---|
564 | struct local_hostlist_entry *entry;
|
---|
565 | size_t namelen;
|
---|
566 | char *entry_name;
|
---|
567 | LWIP_ASSERT("invalid host name (NULL)", hostname != NULL);
|
---|
568 | namelen = strlen(hostname);
|
---|
569 | LWIP_ASSERT("namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN", namelen <= DNS_LOCAL_HOSTLIST_MAX_NAMELEN);
|
---|
570 | entry = (struct local_hostlist_entry *)memp_malloc(MEMP_LOCALHOSTLIST);
|
---|
571 | if (entry == NULL) {
|
---|
572 | return ERR_MEM;
|
---|
573 | }
|
---|
574 | entry_name = (char *)entry + sizeof(struct local_hostlist_entry);
|
---|
575 | MEMCPY(entry_name, hostname, namelen);
|
---|
576 | entry_name[namelen] = 0;
|
---|
577 | entry->name = entry_name;
|
---|
578 | ip_addr_copy(entry->addr, *addr);
|
---|
579 | entry->next = local_hostlist_dynamic;
|
---|
580 | local_hostlist_dynamic = entry;
|
---|
581 | return ERR_OK;
|
---|
582 | }
|
---|
583 | #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC*/
|
---|
584 | #endif /* DNS_LOCAL_HOSTLIST */
|
---|
585 |
|
---|
586 | /**
|
---|
587 | * @ingroup dns
|
---|
588 | * Look up a hostname in the array of known hostnames.
|
---|
589 | *
|
---|
590 | * @note This function only looks in the internal array of known
|
---|
591 | * hostnames, it does not send out a query for the hostname if none
|
---|
592 | * was found. The function dns_enqueue() can be used to send a query
|
---|
593 | * for a hostname.
|
---|
594 | *
|
---|
595 | * @param name the hostname to look up
|
---|
596 | * @param addr the hostname's IP address, as u32_t (instead of ip_addr_t to
|
---|
597 | * better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
|
---|
598 | * was not found in the cached dns_table.
|
---|
599 | * @return ERR_OK if found, ERR_ARG if not found
|
---|
600 | */
|
---|
601 | static err_t
|
---|
602 | dns_lookup(const char *name, ip_addr_t *addr LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype))
|
---|
603 | {
|
---|
604 | u8_t i;
|
---|
605 | #if DNS_LOCAL_HOSTLIST
|
---|
606 | if (dns_lookup_local(name, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) {
|
---|
607 | return ERR_OK;
|
---|
608 | }
|
---|
609 | #endif /* DNS_LOCAL_HOSTLIST */
|
---|
610 | #ifdef DNS_LOOKUP_LOCAL_EXTERN
|
---|
611 | if (DNS_LOOKUP_LOCAL_EXTERN(name, addr, LWIP_DNS_ADDRTYPE_ARG_OR_ZERO(dns_addrtype)) == ERR_OK) {
|
---|
612 | return ERR_OK;
|
---|
613 | }
|
---|
614 | #endif /* DNS_LOOKUP_LOCAL_EXTERN */
|
---|
615 |
|
---|
616 | /* Walk through name list, return entry if found. If not, return NULL. */
|
---|
617 | for (i = 0; i < DNS_TABLE_SIZE; ++i) {
|
---|
618 | if ((dns_table[i].state == DNS_STATE_DONE) &&
|
---|
619 | (lwip_strnicmp(name, dns_table[i].name, sizeof(dns_table[i].name)) == 0) &&
|
---|
620 | LWIP_DNS_ADDRTYPE_MATCH_IP(dns_addrtype, dns_table[i].ipaddr)) {
|
---|
621 | LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
|
---|
622 | ip_addr_debug_print_val(DNS_DEBUG, dns_table[i].ipaddr);
|
---|
623 | LWIP_DEBUGF(DNS_DEBUG, ("\n"));
|
---|
624 | if (addr) {
|
---|
625 | ip_addr_copy(*addr, dns_table[i].ipaddr);
|
---|
626 | }
|
---|
627 | return ERR_OK;
|
---|
628 | }
|
---|
629 | }
|
---|
630 |
|
---|
631 | return ERR_ARG;
|
---|
632 | }
|
---|
633 |
|
---|
634 | /**
|
---|
635 | * Compare the "dotted" name "query" with the encoded name "response"
|
---|
636 | * to make sure an answer from the DNS server matches the current dns_table
|
---|
637 | * entry (otherwise, answers might arrive late for hostname not on the list
|
---|
638 | * any more).
|
---|
639 | *
|
---|
640 | * For now, this function compares case-insensitive to cope with all kinds of
|
---|
641 | * servers. This also means that "dns 0x20 bit encoding" must be checked
|
---|
642 | * externally, if we want to implement it.
|
---|
643 | * Currently, the request is sent exactly as passed in by he user request.
|
---|
644 | *
|
---|
645 | * @param query hostname (not encoded) from the dns_table
|
---|
646 | * @param p pbuf containing the encoded hostname in the DNS response
|
---|
647 | * @param start_offset offset into p where the name starts
|
---|
648 | * @return 0xFFFF: names differ, other: names equal -> offset behind name
|
---|
649 | */
|
---|
650 | static u16_t
|
---|
651 | dns_compare_name(const char *query, struct pbuf *p, u16_t start_offset)
|
---|
652 | {
|
---|
653 | int n;
|
---|
654 | u16_t response_offset = start_offset;
|
---|
655 |
|
---|
656 | do {
|
---|
657 | n = pbuf_try_get_at(p, response_offset);
|
---|
658 | if ((n < 0) || (response_offset == 0xFFFF)) {
|
---|
659 | /* error or overflow */
|
---|
660 | return 0xFFFF;
|
---|
661 | }
|
---|
662 | response_offset++;
|
---|
663 | /** @see RFC 1035 - 4.1.4. Message compression */
|
---|
664 | if ((n & 0xc0) == 0xc0) {
|
---|
665 | /* Compressed name: cannot be equal since we don't send them */
|
---|
666 | return 0xFFFF;
|
---|
667 | } else {
|
---|
668 | /* Not compressed name */
|
---|
669 | while (n > 0) {
|
---|
670 | int c = pbuf_try_get_at(p, response_offset);
|
---|
671 | if (c < 0) {
|
---|
672 | return 0xFFFF;
|
---|
673 | }
|
---|
674 | if (lwip_tolower((*query)) != lwip_tolower((u8_t)c)) {
|
---|
675 | return 0xFFFF;
|
---|
676 | }
|
---|
677 | if (response_offset == 0xFFFF) {
|
---|
678 | /* would overflow */
|
---|
679 | return 0xFFFF;
|
---|
680 | }
|
---|
681 | response_offset++;
|
---|
682 | ++query;
|
---|
683 | --n;
|
---|
684 | }
|
---|
685 | ++query;
|
---|
686 | }
|
---|
687 | n = pbuf_try_get_at(p, response_offset);
|
---|
688 | if (n < 0) {
|
---|
689 | return 0xFFFF;
|
---|
690 | }
|
---|
691 | } while (n != 0);
|
---|
692 |
|
---|
693 | if (response_offset == 0xFFFF) {
|
---|
694 | /* would overflow */
|
---|
695 | return 0xFFFF;
|
---|
696 | }
|
---|
697 | return (u16_t)(response_offset + 1);
|
---|
698 | }
|
---|
699 |
|
---|
700 | /**
|
---|
701 | * Walk through a compact encoded DNS name and return the end of the name.
|
---|
702 | *
|
---|
703 | * @param p pbuf containing the name
|
---|
704 | * @param query_idx start index into p pointing to encoded DNS name in the DNS server response
|
---|
705 | * @return index to end of the name
|
---|
706 | */
|
---|
707 | static u16_t
|
---|
708 | dns_skip_name(struct pbuf *p, u16_t query_idx)
|
---|
709 | {
|
---|
710 | int n;
|
---|
711 | u16_t offset = query_idx;
|
---|
712 |
|
---|
713 | do {
|
---|
714 | n = pbuf_try_get_at(p, offset++);
|
---|
715 | if ((n < 0) || (offset == 0)) {
|
---|
716 | return 0xFFFF;
|
---|
717 | }
|
---|
718 | /** @see RFC 1035 - 4.1.4. Message compression */
|
---|
719 | if ((n & 0xc0) == 0xc0) {
|
---|
720 | /* Compressed name: since we only want to skip it (not check it), stop here */
|
---|
721 | break;
|
---|
722 | } else {
|
---|
723 | /* Not compressed name */
|
---|
724 | if (offset + n >= p->tot_len) {
|
---|
725 | return 0xFFFF;
|
---|
726 | }
|
---|
727 | offset = (u16_t)(offset + n);
|
---|
728 | }
|
---|
729 | n = pbuf_try_get_at(p, offset);
|
---|
730 | if (n < 0) {
|
---|
731 | return 0xFFFF;
|
---|
732 | }
|
---|
733 | } while (n != 0);
|
---|
734 |
|
---|
735 | if (offset == 0xFFFF) {
|
---|
736 | return 0xFFFF;
|
---|
737 | }
|
---|
738 | return (u16_t)(offset + 1);
|
---|
739 | }
|
---|
740 |
|
---|
741 | /**
|
---|
742 | * Send a DNS query packet.
|
---|
743 | *
|
---|
744 | * @param idx the DNS table entry index for which to send a request
|
---|
745 | * @return ERR_OK if packet is sent; an err_t indicating the problem otherwise
|
---|
746 | */
|
---|
747 | static err_t
|
---|
748 | dns_send(u8_t idx)
|
---|
749 | {
|
---|
750 | err_t err;
|
---|
751 | struct dns_hdr hdr;
|
---|
752 | struct dns_query qry;
|
---|
753 | struct pbuf *p;
|
---|
754 | u16_t query_idx, copy_len;
|
---|
755 | const char *hostname, *hostname_part;
|
---|
756 | u8_t n;
|
---|
757 | u8_t pcb_idx;
|
---|
758 | struct dns_table_entry *entry = &dns_table[idx];
|
---|
759 |
|
---|
760 | LWIP_DEBUGF(DNS_DEBUG, ("dns_send: dns_servers[%"U16_F"] \"%s\": request\n",
|
---|
761 | (u16_t)(entry->server_idx), entry->name));
|
---|
762 | LWIP_ASSERT("dns server out of array", entry->server_idx < DNS_MAX_SERVERS);
|
---|
763 | if (ip_addr_isany_val(dns_servers[entry->server_idx])
|
---|
764 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
765 | && !entry->is_mdns
|
---|
766 | #endif
|
---|
767 | ) {
|
---|
768 | /* DNS server not valid anymore, e.g. PPP netif has been shut down */
|
---|
769 | /* call specified callback function if provided */
|
---|
770 | dns_call_found(idx, NULL);
|
---|
771 | /* flush this entry */
|
---|
772 | entry->state = DNS_STATE_UNUSED;
|
---|
773 | return ERR_OK;
|
---|
774 | }
|
---|
775 |
|
---|
776 | /* if here, we have either a new query or a retry on a previous query to process */
|
---|
777 | p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(SIZEOF_DNS_HDR + strlen(entry->name) + 2 +
|
---|
778 | SIZEOF_DNS_QUERY), PBUF_RAM);
|
---|
779 | if (p != NULL) {
|
---|
780 | const ip_addr_t *dst;
|
---|
781 | u16_t dst_port;
|
---|
782 | /* fill dns header */
|
---|
783 | memset(&hdr, 0, SIZEOF_DNS_HDR);
|
---|
784 | hdr.id = lwip_htons(entry->txid);
|
---|
785 | hdr.flags1 = DNS_FLAG1_RD;
|
---|
786 | hdr.numquestions = PP_HTONS(1);
|
---|
787 | pbuf_take(p, &hdr, SIZEOF_DNS_HDR);
|
---|
788 | hostname = entry->name;
|
---|
789 | --hostname;
|
---|
790 |
|
---|
791 | /* convert hostname into suitable query format. */
|
---|
792 | query_idx = SIZEOF_DNS_HDR;
|
---|
793 | do {
|
---|
794 | ++hostname;
|
---|
795 | hostname_part = hostname;
|
---|
796 | for (n = 0; *hostname != '.' && *hostname != 0; ++hostname) {
|
---|
797 | ++n;
|
---|
798 | }
|
---|
799 | copy_len = (u16_t)(hostname - hostname_part);
|
---|
800 | if (query_idx + n + 1 > 0xFFFF) {
|
---|
801 | /* u16_t overflow */
|
---|
802 | goto overflow_return;
|
---|
803 | }
|
---|
804 | pbuf_put_at(p, query_idx, n);
|
---|
805 | pbuf_take_at(p, hostname_part, copy_len, (u16_t)(query_idx + 1));
|
---|
806 | query_idx = (u16_t)(query_idx + n + 1);
|
---|
807 | } while (*hostname != 0);
|
---|
808 | pbuf_put_at(p, query_idx, 0);
|
---|
809 | query_idx++;
|
---|
810 |
|
---|
811 | /* fill dns query */
|
---|
812 | if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) {
|
---|
813 | qry.type = PP_HTONS(DNS_RRTYPE_AAAA);
|
---|
814 | } else {
|
---|
815 | qry.type = PP_HTONS(DNS_RRTYPE_A);
|
---|
816 | }
|
---|
817 | qry.cls = PP_HTONS(DNS_RRCLASS_IN);
|
---|
818 | pbuf_take_at(p, &qry, SIZEOF_DNS_QUERY, query_idx);
|
---|
819 |
|
---|
820 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
|
---|
821 | pcb_idx = entry->pcb_idx;
|
---|
822 | #else
|
---|
823 | pcb_idx = 0;
|
---|
824 | #endif
|
---|
825 | /* send dns packet */
|
---|
826 | LWIP_DEBUGF(DNS_DEBUG, ("sending DNS request ID %d for name \"%s\" to server %d\r\n",
|
---|
827 | entry->txid, entry->name, entry->server_idx));
|
---|
828 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
829 | if (entry->is_mdns) {
|
---|
830 | dst_port = DNS_MQUERY_PORT;
|
---|
831 | #if LWIP_IPV6
|
---|
832 | if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype)) {
|
---|
833 | dst = &dns_mquery_v6group;
|
---|
834 | }
|
---|
835 | #endif
|
---|
836 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
837 | else
|
---|
838 | #endif
|
---|
839 | #if LWIP_IPV4
|
---|
840 | {
|
---|
841 | dst = &dns_mquery_v4group;
|
---|
842 | }
|
---|
843 | #endif
|
---|
844 | } else
|
---|
845 | #endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */
|
---|
846 | {
|
---|
847 | dst_port = DNS_SERVER_PORT;
|
---|
848 | dst = &dns_servers[entry->server_idx];
|
---|
849 | }
|
---|
850 | err = udp_sendto(dns_pcbs[pcb_idx], p, dst, dst_port);
|
---|
851 |
|
---|
852 | /* free pbuf */
|
---|
853 | pbuf_free(p);
|
---|
854 | } else {
|
---|
855 | err = ERR_MEM;
|
---|
856 | }
|
---|
857 |
|
---|
858 | return err;
|
---|
859 | overflow_return:
|
---|
860 | pbuf_free(p);
|
---|
861 | return ERR_VAL;
|
---|
862 | }
|
---|
863 |
|
---|
864 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
|
---|
865 | static struct udp_pcb *
|
---|
866 | dns_alloc_random_port(void)
|
---|
867 | {
|
---|
868 | err_t err;
|
---|
869 | struct udp_pcb *pcb;
|
---|
870 |
|
---|
871 | pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
|
---|
872 | if (pcb == NULL) {
|
---|
873 | /* out of memory, have to reuse an existing pcb */
|
---|
874 | return NULL;
|
---|
875 | }
|
---|
876 | do {
|
---|
877 | u16_t port = (u16_t)DNS_RAND_TXID();
|
---|
878 | if (DNS_PORT_ALLOWED(port)) {
|
---|
879 | err = udp_bind(pcb, IP_ANY_TYPE, port);
|
---|
880 | } else {
|
---|
881 | /* this port is not allowed, try again */
|
---|
882 | err = ERR_USE;
|
---|
883 | }
|
---|
884 | } while (err == ERR_USE);
|
---|
885 | if (err != ERR_OK) {
|
---|
886 | udp_remove(pcb);
|
---|
887 | return NULL;
|
---|
888 | }
|
---|
889 | udp_recv(pcb, dns_recv, NULL);
|
---|
890 | return pcb;
|
---|
891 | }
|
---|
892 |
|
---|
893 | /**
|
---|
894 | * dns_alloc_pcb() - allocates a new pcb (or reuses an existing one) to be used
|
---|
895 | * for sending a request
|
---|
896 | *
|
---|
897 | * @return an index into dns_pcbs
|
---|
898 | */
|
---|
899 | static u8_t
|
---|
900 | dns_alloc_pcb(void)
|
---|
901 | {
|
---|
902 | u8_t i;
|
---|
903 | u8_t idx;
|
---|
904 |
|
---|
905 | for (i = 0; i < DNS_MAX_SOURCE_PORTS; i++) {
|
---|
906 | if (dns_pcbs[i] == NULL) {
|
---|
907 | break;
|
---|
908 | }
|
---|
909 | }
|
---|
910 | if (i < DNS_MAX_SOURCE_PORTS) {
|
---|
911 | dns_pcbs[i] = dns_alloc_random_port();
|
---|
912 | if (dns_pcbs[i] != NULL) {
|
---|
913 | /* succeeded */
|
---|
914 | dns_last_pcb_idx = i;
|
---|
915 | return i;
|
---|
916 | }
|
---|
917 | }
|
---|
918 | /* if we come here, creating a new UDP pcb failed, so we have to use
|
---|
919 | an already existing one (so overflow is no issue) */
|
---|
920 | for (i = 0, idx = (u8_t)(dns_last_pcb_idx + 1); i < DNS_MAX_SOURCE_PORTS; i++, idx++) {
|
---|
921 | if (idx >= DNS_MAX_SOURCE_PORTS) {
|
---|
922 | idx = 0;
|
---|
923 | }
|
---|
924 | if (dns_pcbs[idx] != NULL) {
|
---|
925 | dns_last_pcb_idx = idx;
|
---|
926 | return idx;
|
---|
927 | }
|
---|
928 | }
|
---|
929 | return DNS_MAX_SOURCE_PORTS;
|
---|
930 | }
|
---|
931 | #endif /* ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0) */
|
---|
932 |
|
---|
933 | /**
|
---|
934 | * dns_call_found() - call the found callback and check if there are duplicate
|
---|
935 | * entries for the given hostname. If there are any, their found callback will
|
---|
936 | * be called and they will be removed.
|
---|
937 | *
|
---|
938 | * @param idx dns table index of the entry that is resolved or removed
|
---|
939 | * @param addr IP address for the hostname (or NULL on error or memory shortage)
|
---|
940 | */
|
---|
941 | static void
|
---|
942 | dns_call_found(u8_t idx, ip_addr_t *addr)
|
---|
943 | {
|
---|
944 | #if ((LWIP_DNS_SECURE & (LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING | LWIP_DNS_SECURE_RAND_SRC_PORT)) != 0)
|
---|
945 | u8_t i;
|
---|
946 | #endif
|
---|
947 |
|
---|
948 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
949 | if (addr != NULL) {
|
---|
950 | /* check that address type matches the request and adapt the table entry */
|
---|
951 | if (IP_IS_V6_VAL(*addr)) {
|
---|
952 | LWIP_ASSERT("invalid response", LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype));
|
---|
953 | dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6;
|
---|
954 | } else {
|
---|
955 | LWIP_ASSERT("invalid response", !LWIP_DNS_ADDRTYPE_IS_IPV6(dns_table[idx].reqaddrtype));
|
---|
956 | dns_table[idx].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4;
|
---|
957 | }
|
---|
958 | }
|
---|
959 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
960 |
|
---|
961 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
|
---|
962 | for (i = 0; i < DNS_MAX_REQUESTS; i++) {
|
---|
963 | if (dns_requests[i].found && (dns_requests[i].dns_table_idx == idx)) {
|
---|
964 | (*dns_requests[i].found)(dns_table[idx].name, addr, dns_requests[i].arg);
|
---|
965 | /* flush this entry */
|
---|
966 | dns_requests[i].found = NULL;
|
---|
967 | }
|
---|
968 | }
|
---|
969 | #else
|
---|
970 | if (dns_requests[idx].found) {
|
---|
971 | (*dns_requests[idx].found)(dns_table[idx].name, addr, dns_requests[idx].arg);
|
---|
972 | }
|
---|
973 | dns_requests[idx].found = NULL;
|
---|
974 | #endif
|
---|
975 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
|
---|
976 | /* close the pcb used unless other request are using it */
|
---|
977 | for (i = 0; i < DNS_MAX_REQUESTS; i++) {
|
---|
978 | if (i == idx) {
|
---|
979 | continue; /* only check other requests */
|
---|
980 | }
|
---|
981 | if (dns_table[i].state == DNS_STATE_ASKING) {
|
---|
982 | if (dns_table[i].pcb_idx == dns_table[idx].pcb_idx) {
|
---|
983 | /* another request is still using the same pcb */
|
---|
984 | dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS;
|
---|
985 | break;
|
---|
986 | }
|
---|
987 | }
|
---|
988 | }
|
---|
989 | if (dns_table[idx].pcb_idx < DNS_MAX_SOURCE_PORTS) {
|
---|
990 | /* if we come here, the pcb is not used any more and can be removed */
|
---|
991 | udp_remove(dns_pcbs[dns_table[idx].pcb_idx]);
|
---|
992 | dns_pcbs[dns_table[idx].pcb_idx] = NULL;
|
---|
993 | dns_table[idx].pcb_idx = DNS_MAX_SOURCE_PORTS;
|
---|
994 | }
|
---|
995 | #endif
|
---|
996 | }
|
---|
997 |
|
---|
998 | /* Create a query transmission ID that is unique for all outstanding queries */
|
---|
999 | static u16_t
|
---|
1000 | dns_create_txid(void)
|
---|
1001 | {
|
---|
1002 | u16_t txid;
|
---|
1003 | u8_t i;
|
---|
1004 |
|
---|
1005 | again:
|
---|
1006 | txid = (u16_t)DNS_RAND_TXID();
|
---|
1007 |
|
---|
1008 | /* check whether the ID is unique */
|
---|
1009 | for (i = 0; i < DNS_TABLE_SIZE; i++) {
|
---|
1010 | if ((dns_table[i].state == DNS_STATE_ASKING) &&
|
---|
1011 | (dns_table[i].txid == txid)) {
|
---|
1012 | /* ID already used by another pending query */
|
---|
1013 | goto again;
|
---|
1014 | }
|
---|
1015 | }
|
---|
1016 |
|
---|
1017 | return txid;
|
---|
1018 | }
|
---|
1019 |
|
---|
1020 | /**
|
---|
1021 | * Check whether there are other backup DNS servers available to try
|
---|
1022 | */
|
---|
1023 | static u8_t
|
---|
1024 | dns_backupserver_available(struct dns_table_entry *pentry)
|
---|
1025 | {
|
---|
1026 | u8_t ret = 0;
|
---|
1027 |
|
---|
1028 | if (pentry) {
|
---|
1029 | if ((pentry->server_idx + 1 < DNS_MAX_SERVERS) && !ip_addr_isany_val(dns_servers[pentry->server_idx + 1])) {
|
---|
1030 | ret = 1;
|
---|
1031 | }
|
---|
1032 | }
|
---|
1033 |
|
---|
1034 | return ret;
|
---|
1035 | }
|
---|
1036 |
|
---|
1037 | /**
|
---|
1038 | * dns_check_entry() - see if entry has not yet been queried and, if so, sends out a query.
|
---|
1039 | * Check an entry in the dns_table:
|
---|
1040 | * - send out query for new entries
|
---|
1041 | * - retry old pending entries on timeout (also with different servers)
|
---|
1042 | * - remove completed entries from the table if their TTL has expired
|
---|
1043 | *
|
---|
1044 | * @param i index of the dns_table entry to check
|
---|
1045 | */
|
---|
1046 | static void
|
---|
1047 | dns_check_entry(u8_t i)
|
---|
1048 | {
|
---|
1049 | err_t err;
|
---|
1050 | struct dns_table_entry *entry = &dns_table[i];
|
---|
1051 |
|
---|
1052 | LWIP_ASSERT("array index out of bounds", i < DNS_TABLE_SIZE);
|
---|
1053 |
|
---|
1054 | switch (entry->state) {
|
---|
1055 | case DNS_STATE_NEW:
|
---|
1056 | /* initialize new entry */
|
---|
1057 | entry->txid = dns_create_txid();
|
---|
1058 | entry->state = DNS_STATE_ASKING;
|
---|
1059 | entry->server_idx = 0;
|
---|
1060 | entry->tmr = 1;
|
---|
1061 | entry->retries = 0;
|
---|
1062 |
|
---|
1063 | /* send DNS packet for this entry */
|
---|
1064 | err = dns_send(i);
|
---|
1065 | if (err != ERR_OK) {
|
---|
1066 | LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
|
---|
1067 | ("dns_send returned error: %s\n", lwip_strerr(err)));
|
---|
1068 | }
|
---|
1069 | break;
|
---|
1070 | case DNS_STATE_ASKING:
|
---|
1071 | if (--entry->tmr == 0) {
|
---|
1072 | if (++entry->retries == DNS_MAX_RETRIES) {
|
---|
1073 | if (dns_backupserver_available(entry)
|
---|
1074 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
1075 | && !entry->is_mdns
|
---|
1076 | #endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */
|
---|
1077 | ) {
|
---|
1078 | /* change of server */
|
---|
1079 | entry->server_idx++;
|
---|
1080 | entry->tmr = 1;
|
---|
1081 | entry->retries = 0;
|
---|
1082 | } else {
|
---|
1083 | LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": timeout\n", entry->name));
|
---|
1084 | /* call specified callback function if provided */
|
---|
1085 | dns_call_found(i, NULL);
|
---|
1086 | /* flush this entry */
|
---|
1087 | entry->state = DNS_STATE_UNUSED;
|
---|
1088 | break;
|
---|
1089 | }
|
---|
1090 | } else {
|
---|
1091 | /* wait longer for the next retry */
|
---|
1092 | entry->tmr = entry->retries;
|
---|
1093 | }
|
---|
1094 |
|
---|
1095 | /* send DNS packet for this entry */
|
---|
1096 | err = dns_send(i);
|
---|
1097 | if (err != ERR_OK) {
|
---|
1098 | LWIP_DEBUGF(DNS_DEBUG | LWIP_DBG_LEVEL_WARNING,
|
---|
1099 | ("dns_send returned error: %s\n", lwip_strerr(err)));
|
---|
1100 | }
|
---|
1101 | }
|
---|
1102 | break;
|
---|
1103 | case DNS_STATE_DONE:
|
---|
1104 | /* if the time to live is nul */
|
---|
1105 | if ((entry->ttl == 0) || (--entry->ttl == 0)) {
|
---|
1106 | LWIP_DEBUGF(DNS_DEBUG, ("dns_check_entry: \"%s\": flush\n", entry->name));
|
---|
1107 | /* flush this entry, there cannot be any related pending entries in this state */
|
---|
1108 | entry->state = DNS_STATE_UNUSED;
|
---|
1109 | }
|
---|
1110 | break;
|
---|
1111 | case DNS_STATE_UNUSED:
|
---|
1112 | /* nothing to do */
|
---|
1113 | break;
|
---|
1114 | default:
|
---|
1115 | LWIP_ASSERT("unknown dns_table entry state:", 0);
|
---|
1116 | break;
|
---|
1117 | }
|
---|
1118 | }
|
---|
1119 |
|
---|
1120 | /**
|
---|
1121 | * Call dns_check_entry for each entry in dns_table - check all entries.
|
---|
1122 | */
|
---|
1123 | static void
|
---|
1124 | dns_check_entries(void)
|
---|
1125 | {
|
---|
1126 | u8_t i;
|
---|
1127 |
|
---|
1128 | for (i = 0; i < DNS_TABLE_SIZE; ++i) {
|
---|
1129 | dns_check_entry(i);
|
---|
1130 | }
|
---|
1131 | }
|
---|
1132 |
|
---|
1133 | /**
|
---|
1134 | * Save TTL and call dns_call_found for correct response.
|
---|
1135 | */
|
---|
1136 | static void
|
---|
1137 | dns_correct_response(u8_t idx, u32_t ttl)
|
---|
1138 | {
|
---|
1139 | struct dns_table_entry *entry = &dns_table[idx];
|
---|
1140 |
|
---|
1141 | entry->state = DNS_STATE_DONE;
|
---|
1142 |
|
---|
1143 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response = ", entry->name));
|
---|
1144 | ip_addr_debug_print_val(DNS_DEBUG, entry->ipaddr);
|
---|
1145 | LWIP_DEBUGF(DNS_DEBUG, ("\n"));
|
---|
1146 |
|
---|
1147 | /* read the answer resource record's TTL, and maximize it if needed */
|
---|
1148 | entry->ttl = ttl;
|
---|
1149 | if (entry->ttl > DNS_MAX_TTL) {
|
---|
1150 | entry->ttl = DNS_MAX_TTL;
|
---|
1151 | }
|
---|
1152 | dns_call_found(idx, &entry->ipaddr);
|
---|
1153 |
|
---|
1154 | if (entry->ttl == 0) {
|
---|
1155 | /* RFC 883, page 29: "Zero values are
|
---|
1156 | interpreted to mean that the RR can only be used for the
|
---|
1157 | transaction in progress, and should not be cached."
|
---|
1158 | -> flush this entry now */
|
---|
1159 | /* entry reused during callback? */
|
---|
1160 | if (entry->state == DNS_STATE_DONE) {
|
---|
1161 | entry->state = DNS_STATE_UNUSED;
|
---|
1162 | }
|
---|
1163 | }
|
---|
1164 | }
|
---|
1165 |
|
---|
1166 | /**
|
---|
1167 | * Receive input function for DNS response packets arriving for the dns UDP pcb.
|
---|
1168 | */
|
---|
1169 | static void
|
---|
1170 | dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
|
---|
1171 | {
|
---|
1172 | u8_t i;
|
---|
1173 | u16_t txid;
|
---|
1174 | u16_t res_idx;
|
---|
1175 | struct dns_hdr hdr;
|
---|
1176 | struct dns_answer ans;
|
---|
1177 | struct dns_query qry;
|
---|
1178 | u16_t nquestions, nanswers;
|
---|
1179 |
|
---|
1180 | LWIP_UNUSED_ARG(arg);
|
---|
1181 | LWIP_UNUSED_ARG(pcb);
|
---|
1182 | LWIP_UNUSED_ARG(port);
|
---|
1183 |
|
---|
1184 | /* is the dns message big enough ? */
|
---|
1185 | if (p->tot_len < (SIZEOF_DNS_HDR + SIZEOF_DNS_QUERY)) {
|
---|
1186 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: pbuf too small\n"));
|
---|
1187 | /* free pbuf and return */
|
---|
1188 | goto ignore_packet;
|
---|
1189 | }
|
---|
1190 |
|
---|
1191 | /* copy dns payload inside static buffer for processing */
|
---|
1192 | if (pbuf_copy_partial(p, &hdr, SIZEOF_DNS_HDR, 0) == SIZEOF_DNS_HDR) {
|
---|
1193 | /* Match the ID in the DNS header with the name table. */
|
---|
1194 | txid = lwip_htons(hdr.id);
|
---|
1195 | for (i = 0; i < DNS_TABLE_SIZE; i++) {
|
---|
1196 | struct dns_table_entry *entry = &dns_table[i];
|
---|
1197 | if ((entry->state == DNS_STATE_ASKING) &&
|
---|
1198 | (entry->txid == txid)) {
|
---|
1199 |
|
---|
1200 | /* We only care about the question(s) and the answers. The authrr
|
---|
1201 | and the extrarr are simply discarded. */
|
---|
1202 | nquestions = lwip_htons(hdr.numquestions);
|
---|
1203 | nanswers = lwip_htons(hdr.numanswers);
|
---|
1204 |
|
---|
1205 | /* Check for correct response. */
|
---|
1206 | if ((hdr.flags1 & DNS_FLAG1_RESPONSE) == 0) {
|
---|
1207 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": not a response\n", entry->name));
|
---|
1208 | goto ignore_packet; /* ignore this packet */
|
---|
1209 | }
|
---|
1210 | if (nquestions != 1) {
|
---|
1211 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
|
---|
1212 | goto ignore_packet; /* ignore this packet */
|
---|
1213 | }
|
---|
1214 |
|
---|
1215 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
1216 | if (!entry->is_mdns)
|
---|
1217 | #endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */
|
---|
1218 | {
|
---|
1219 | /* Check whether response comes from the same network address to which the
|
---|
1220 | question was sent. (RFC 5452) */
|
---|
1221 | if (!ip_addr_cmp(addr, &dns_servers[entry->server_idx])) {
|
---|
1222 | goto ignore_packet; /* ignore this packet */
|
---|
1223 | }
|
---|
1224 | }
|
---|
1225 |
|
---|
1226 | /* Check if the name in the "question" part match with the name in the entry and
|
---|
1227 | skip it if equal. */
|
---|
1228 | res_idx = dns_compare_name(entry->name, p, SIZEOF_DNS_HDR);
|
---|
1229 | if (res_idx == 0xFFFF) {
|
---|
1230 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
|
---|
1231 | goto ignore_packet; /* ignore this packet */
|
---|
1232 | }
|
---|
1233 |
|
---|
1234 | /* check if "question" part matches the request */
|
---|
1235 | if (pbuf_copy_partial(p, &qry, SIZEOF_DNS_QUERY, res_idx) != SIZEOF_DNS_QUERY) {
|
---|
1236 | goto ignore_packet; /* ignore this packet */
|
---|
1237 | }
|
---|
1238 | if ((qry.cls != PP_HTONS(DNS_RRCLASS_IN)) ||
|
---|
1239 | (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_AAAA))) ||
|
---|
1240 | (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype) && (qry.type != PP_HTONS(DNS_RRTYPE_A)))) {
|
---|
1241 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": response not match to query\n", entry->name));
|
---|
1242 | goto ignore_packet; /* ignore this packet */
|
---|
1243 | }
|
---|
1244 | /* skip the rest of the "question" part */
|
---|
1245 | if (res_idx + SIZEOF_DNS_QUERY > 0xFFFF) {
|
---|
1246 | goto ignore_packet;
|
---|
1247 | }
|
---|
1248 | res_idx = (u16_t)(res_idx + SIZEOF_DNS_QUERY);
|
---|
1249 |
|
---|
1250 | /* Check for error. If so, call callback to inform. */
|
---|
1251 | if (hdr.flags2 & DNS_FLAG2_ERR_MASK) {
|
---|
1252 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in flags\n", entry->name));
|
---|
1253 |
|
---|
1254 | /* if there is another backup DNS server to try
|
---|
1255 | * then don't stop the DNS request
|
---|
1256 | */
|
---|
1257 | if (dns_backupserver_available(entry)) {
|
---|
1258 | /* avoid retrying the same server */
|
---|
1259 | entry->retries = DNS_MAX_RETRIES-1;
|
---|
1260 | entry->tmr = 1;
|
---|
1261 |
|
---|
1262 | /* contact next available server for this entry */
|
---|
1263 | dns_check_entry(i);
|
---|
1264 |
|
---|
1265 | goto ignore_packet;
|
---|
1266 | }
|
---|
1267 | } else {
|
---|
1268 | while ((nanswers > 0) && (res_idx < p->tot_len)) {
|
---|
1269 | /* skip answer resource record's host name */
|
---|
1270 | res_idx = dns_skip_name(p, res_idx);
|
---|
1271 | if (res_idx == 0xFFFF) {
|
---|
1272 | goto ignore_packet; /* ignore this packet */
|
---|
1273 | }
|
---|
1274 |
|
---|
1275 | /* Check for IP address type and Internet class. Others are discarded. */
|
---|
1276 | if (pbuf_copy_partial(p, &ans, SIZEOF_DNS_ANSWER, res_idx) != SIZEOF_DNS_ANSWER) {
|
---|
1277 | goto ignore_packet; /* ignore this packet */
|
---|
1278 | }
|
---|
1279 | if (res_idx + SIZEOF_DNS_ANSWER > 0xFFFF) {
|
---|
1280 | goto ignore_packet;
|
---|
1281 | }
|
---|
1282 | res_idx = (u16_t)(res_idx + SIZEOF_DNS_ANSWER);
|
---|
1283 |
|
---|
1284 | if (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) {
|
---|
1285 | #if LWIP_IPV4
|
---|
1286 | if ((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.len == PP_HTONS(sizeof(ip4_addr_t)))) {
|
---|
1287 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1288 | if (!LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype))
|
---|
1289 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1290 | {
|
---|
1291 | ip4_addr_t ip4addr;
|
---|
1292 | /* read the IP address after answer resource record's header */
|
---|
1293 | if (pbuf_copy_partial(p, &ip4addr, sizeof(ip4_addr_t), res_idx) != sizeof(ip4_addr_t)) {
|
---|
1294 | goto ignore_packet; /* ignore this packet */
|
---|
1295 | }
|
---|
1296 | ip_addr_copy_from_ip4(dns_table[i].ipaddr, ip4addr);
|
---|
1297 | pbuf_free(p);
|
---|
1298 | /* handle correct response */
|
---|
1299 | dns_correct_response(i, lwip_ntohl(ans.ttl));
|
---|
1300 | return;
|
---|
1301 | }
|
---|
1302 | }
|
---|
1303 | #endif /* LWIP_IPV4 */
|
---|
1304 | #if LWIP_IPV6
|
---|
1305 | if ((ans.type == PP_HTONS(DNS_RRTYPE_AAAA)) && (ans.len == PP_HTONS(sizeof(ip6_addr_p_t)))) {
|
---|
1306 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1307 | if (LWIP_DNS_ADDRTYPE_IS_IPV6(entry->reqaddrtype))
|
---|
1308 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1309 | {
|
---|
1310 | ip6_addr_p_t ip6addr;
|
---|
1311 | /* read the IP address after answer resource record's header */
|
---|
1312 | if (pbuf_copy_partial(p, &ip6addr, sizeof(ip6_addr_p_t), res_idx) != sizeof(ip6_addr_p_t)) {
|
---|
1313 | goto ignore_packet; /* ignore this packet */
|
---|
1314 | }
|
---|
1315 | /* @todo: scope ip6addr? Might be required for link-local addresses at least? */
|
---|
1316 | ip_addr_copy_from_ip6_packed(dns_table[i].ipaddr, ip6addr);
|
---|
1317 | pbuf_free(p);
|
---|
1318 | /* handle correct response */
|
---|
1319 | dns_correct_response(i, lwip_ntohl(ans.ttl));
|
---|
1320 | return;
|
---|
1321 | }
|
---|
1322 | }
|
---|
1323 | #endif /* LWIP_IPV6 */
|
---|
1324 | }
|
---|
1325 | /* skip this answer */
|
---|
1326 | if ((int)(res_idx + lwip_htons(ans.len)) > 0xFFFF) {
|
---|
1327 | goto ignore_packet; /* ignore this packet */
|
---|
1328 | }
|
---|
1329 | res_idx = (u16_t)(res_idx + lwip_htons(ans.len));
|
---|
1330 | --nanswers;
|
---|
1331 | }
|
---|
1332 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1333 | if ((entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) ||
|
---|
1334 | (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) {
|
---|
1335 | if (entry->reqaddrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) {
|
---|
1336 | /* IPv4 failed, try IPv6 */
|
---|
1337 | dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV6;
|
---|
1338 | } else {
|
---|
1339 | /* IPv6 failed, try IPv4 */
|
---|
1340 | dns_table[i].reqaddrtype = LWIP_DNS_ADDRTYPE_IPV4;
|
---|
1341 | }
|
---|
1342 | pbuf_free(p);
|
---|
1343 | dns_table[i].state = DNS_STATE_NEW;
|
---|
1344 | dns_check_entry(i);
|
---|
1345 | return;
|
---|
1346 | }
|
---|
1347 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1348 | LWIP_DEBUGF(DNS_DEBUG, ("dns_recv: \"%s\": error in response\n", entry->name));
|
---|
1349 | }
|
---|
1350 | /* call callback to indicate error, clean up memory and return */
|
---|
1351 | pbuf_free(p);
|
---|
1352 | dns_call_found(i, NULL);
|
---|
1353 | dns_table[i].state = DNS_STATE_UNUSED;
|
---|
1354 | return;
|
---|
1355 | }
|
---|
1356 | }
|
---|
1357 | }
|
---|
1358 |
|
---|
1359 | ignore_packet:
|
---|
1360 | /* deallocate memory and return */
|
---|
1361 | pbuf_free(p);
|
---|
1362 | return;
|
---|
1363 | }
|
---|
1364 |
|
---|
1365 | /**
|
---|
1366 | * Queues a new hostname to resolve and sends out a DNS query for that hostname
|
---|
1367 | *
|
---|
1368 | * @param name the hostname that is to be queried
|
---|
1369 | * @param hostnamelen length of the hostname
|
---|
1370 | * @param found a callback function to be called on success, failure or timeout
|
---|
1371 | * @param callback_arg argument to pass to the callback function
|
---|
1372 | * @return err_t return code.
|
---|
1373 | */
|
---|
1374 | static err_t
|
---|
1375 | dns_enqueue(const char *name, size_t hostnamelen, dns_found_callback found,
|
---|
1376 | void *callback_arg LWIP_DNS_ADDRTYPE_ARG(u8_t dns_addrtype) LWIP_DNS_ISMDNS_ARG(u8_t is_mdns))
|
---|
1377 | {
|
---|
1378 | u8_t i;
|
---|
1379 | u8_t lseq, lseqi;
|
---|
1380 | struct dns_table_entry *entry = NULL;
|
---|
1381 | size_t namelen;
|
---|
1382 | struct dns_req_entry *req;
|
---|
1383 |
|
---|
1384 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
|
---|
1385 | u8_t r;
|
---|
1386 | /* check for duplicate entries */
|
---|
1387 | for (i = 0; i < DNS_TABLE_SIZE; i++) {
|
---|
1388 | if ((dns_table[i].state == DNS_STATE_ASKING) &&
|
---|
1389 | (lwip_strnicmp(name, dns_table[i].name, sizeof(dns_table[i].name)) == 0)) {
|
---|
1390 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1391 | if (dns_table[i].reqaddrtype != dns_addrtype) {
|
---|
1392 | /* requested address types don't match
|
---|
1393 | this can lead to 2 concurrent requests, but mixing the address types
|
---|
1394 | for the same host should not be that common */
|
---|
1395 | continue;
|
---|
1396 | }
|
---|
1397 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1398 | /* this is a duplicate entry, find a free request entry */
|
---|
1399 | for (r = 0; r < DNS_MAX_REQUESTS; r++) {
|
---|
1400 | if (dns_requests[r].found == 0) {
|
---|
1401 | dns_requests[r].found = found;
|
---|
1402 | dns_requests[r].arg = callback_arg;
|
---|
1403 | dns_requests[r].dns_table_idx = i;
|
---|
1404 | LWIP_DNS_SET_ADDRTYPE(dns_requests[r].reqaddrtype, dns_addrtype);
|
---|
1405 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": duplicate request\n", name));
|
---|
1406 | return ERR_INPROGRESS;
|
---|
1407 | }
|
---|
1408 | }
|
---|
1409 | }
|
---|
1410 | }
|
---|
1411 | /* no duplicate entries found */
|
---|
1412 | #endif
|
---|
1413 |
|
---|
1414 | /* search an unused entry, or the oldest one */
|
---|
1415 | lseq = 0;
|
---|
1416 | lseqi = DNS_TABLE_SIZE;
|
---|
1417 | for (i = 0; i < DNS_TABLE_SIZE; ++i) {
|
---|
1418 | entry = &dns_table[i];
|
---|
1419 | /* is it an unused entry ? */
|
---|
1420 | if (entry->state == DNS_STATE_UNUSED) {
|
---|
1421 | break;
|
---|
1422 | }
|
---|
1423 | /* check if this is the oldest completed entry */
|
---|
1424 | if (entry->state == DNS_STATE_DONE) {
|
---|
1425 | u8_t age = (u8_t)(dns_seqno - entry->seqno);
|
---|
1426 | if (age > lseq) {
|
---|
1427 | lseq = age;
|
---|
1428 | lseqi = i;
|
---|
1429 | }
|
---|
1430 | }
|
---|
1431 | }
|
---|
1432 |
|
---|
1433 | /* if we don't have found an unused entry, use the oldest completed one */
|
---|
1434 | if (i == DNS_TABLE_SIZE) {
|
---|
1435 | if ((lseqi >= DNS_TABLE_SIZE) || (dns_table[lseqi].state != DNS_STATE_DONE)) {
|
---|
1436 | /* no entry can be used now, table is full */
|
---|
1437 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS entries table is full\n", name));
|
---|
1438 | return ERR_MEM;
|
---|
1439 | } else {
|
---|
1440 | /* use the oldest completed one */
|
---|
1441 | i = lseqi;
|
---|
1442 | entry = &dns_table[i];
|
---|
1443 | }
|
---|
1444 | }
|
---|
1445 |
|
---|
1446 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_NO_MULTIPLE_OUTSTANDING) != 0)
|
---|
1447 | /* find a free request entry */
|
---|
1448 | req = NULL;
|
---|
1449 | for (r = 0; r < DNS_MAX_REQUESTS; r++) {
|
---|
1450 | if (dns_requests[r].found == NULL) {
|
---|
1451 | req = &dns_requests[r];
|
---|
1452 | break;
|
---|
1453 | }
|
---|
1454 | }
|
---|
1455 | if (req == NULL) {
|
---|
1456 | /* no request entry can be used now, table is full */
|
---|
1457 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": DNS request entries table is full\n", name));
|
---|
1458 | return ERR_MEM;
|
---|
1459 | }
|
---|
1460 | req->dns_table_idx = i;
|
---|
1461 | #else
|
---|
1462 | /* in this configuration, the entry index is the same as the request index */
|
---|
1463 | req = &dns_requests[i];
|
---|
1464 | #endif
|
---|
1465 |
|
---|
1466 | /* use this entry */
|
---|
1467 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS entry %"U16_F"\n", name, (u16_t)(i)));
|
---|
1468 |
|
---|
1469 | /* fill the entry */
|
---|
1470 | entry->state = DNS_STATE_NEW;
|
---|
1471 | entry->seqno = dns_seqno;
|
---|
1472 | LWIP_DNS_SET_ADDRTYPE(entry->reqaddrtype, dns_addrtype);
|
---|
1473 | LWIP_DNS_SET_ADDRTYPE(req->reqaddrtype, dns_addrtype);
|
---|
1474 | req->found = found;
|
---|
1475 | req->arg = callback_arg;
|
---|
1476 | namelen = LWIP_MIN(hostnamelen, DNS_MAX_NAME_LENGTH - 1);
|
---|
1477 | MEMCPY(entry->name, name, namelen);
|
---|
1478 | entry->name[namelen] = 0;
|
---|
1479 |
|
---|
1480 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) != 0)
|
---|
1481 | entry->pcb_idx = dns_alloc_pcb();
|
---|
1482 | if (entry->pcb_idx >= DNS_MAX_SOURCE_PORTS) {
|
---|
1483 | /* failed to get a UDP pcb */
|
---|
1484 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": failed to allocate a pcb\n", name));
|
---|
1485 | entry->state = DNS_STATE_UNUSED;
|
---|
1486 | req->found = NULL;
|
---|
1487 | return ERR_MEM;
|
---|
1488 | }
|
---|
1489 | LWIP_DEBUGF(DNS_DEBUG, ("dns_enqueue: \"%s\": use DNS pcb %"U16_F"\n", name, (u16_t)(entry->pcb_idx)));
|
---|
1490 | #endif
|
---|
1491 |
|
---|
1492 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
1493 | entry->is_mdns = is_mdns;
|
---|
1494 | #endif
|
---|
1495 |
|
---|
1496 | dns_seqno++;
|
---|
1497 |
|
---|
1498 | /* force to send query without waiting timer */
|
---|
1499 | dns_check_entry(i);
|
---|
1500 |
|
---|
1501 | /* dns query is enqueued */
|
---|
1502 | return ERR_INPROGRESS;
|
---|
1503 | }
|
---|
1504 |
|
---|
1505 | /**
|
---|
1506 | * @ingroup dns
|
---|
1507 | * Resolve a hostname (string) into an IP address.
|
---|
1508 | * NON-BLOCKING callback version for use with raw API!!!
|
---|
1509 | *
|
---|
1510 | * Returns immediately with one of err_t return codes:
|
---|
1511 | * - ERR_OK if hostname is a valid IP address string or the host
|
---|
1512 | * name is already in the local names table.
|
---|
1513 | * - ERR_INPROGRESS enqueue a request to be sent to the DNS server
|
---|
1514 | * for resolution if no errors are present.
|
---|
1515 | * - ERR_ARG: dns client not initialized or invalid hostname
|
---|
1516 | *
|
---|
1517 | * @param hostname the hostname that is to be queried
|
---|
1518 | * @param addr pointer to a ip_addr_t where to store the address if it is already
|
---|
1519 | * cached in the dns_table (only valid if ERR_OK is returned!)
|
---|
1520 | * @param found a callback function to be called on success, failure or timeout (only if
|
---|
1521 | * ERR_INPROGRESS is returned!)
|
---|
1522 | * @param callback_arg argument to pass to the callback function
|
---|
1523 | * @return a err_t return code.
|
---|
1524 | */
|
---|
1525 | err_t
|
---|
1526 | dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
|
---|
1527 | void *callback_arg)
|
---|
1528 | {
|
---|
1529 | return dns_gethostbyname_addrtype(hostname, addr, found, callback_arg, LWIP_DNS_ADDRTYPE_DEFAULT);
|
---|
1530 | }
|
---|
1531 |
|
---|
1532 | /**
|
---|
1533 | * @ingroup dns
|
---|
1534 | * Like dns_gethostbyname, but returned address type can be controlled:
|
---|
1535 | * @param hostname the hostname that is to be queried
|
---|
1536 | * @param addr pointer to a ip_addr_t where to store the address if it is already
|
---|
1537 | * cached in the dns_table (only valid if ERR_OK is returned!)
|
---|
1538 | * @param found a callback function to be called on success, failure or timeout (only if
|
---|
1539 | * ERR_INPROGRESS is returned!)
|
---|
1540 | * @param callback_arg argument to pass to the callback function
|
---|
1541 | * @param dns_addrtype - LWIP_DNS_ADDRTYPE_IPV4_IPV6: try to resolve IPv4 first, try IPv6 if IPv4 fails only
|
---|
1542 | * - LWIP_DNS_ADDRTYPE_IPV6_IPV4: try to resolve IPv6 first, try IPv4 if IPv6 fails only
|
---|
1543 | * - LWIP_DNS_ADDRTYPE_IPV4: try to resolve IPv4 only
|
---|
1544 | * - LWIP_DNS_ADDRTYPE_IPV6: try to resolve IPv6 only
|
---|
1545 | */
|
---|
1546 | err_t
|
---|
1547 | dns_gethostbyname_addrtype(const char *hostname, ip_addr_t *addr, dns_found_callback found,
|
---|
1548 | void *callback_arg, u8_t dns_addrtype)
|
---|
1549 | {
|
---|
1550 | size_t hostnamelen;
|
---|
1551 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
1552 | u8_t is_mdns;
|
---|
1553 | #endif
|
---|
1554 | /* not initialized or no valid server yet, or invalid addr pointer
|
---|
1555 | * or invalid hostname or invalid hostname length */
|
---|
1556 | if ((addr == NULL) ||
|
---|
1557 | (!hostname) || (!hostname[0])) {
|
---|
1558 | return ERR_ARG;
|
---|
1559 | }
|
---|
1560 | #if ((LWIP_DNS_SECURE & LWIP_DNS_SECURE_RAND_SRC_PORT) == 0)
|
---|
1561 | if (dns_pcbs[0] == NULL) {
|
---|
1562 | return ERR_ARG;
|
---|
1563 | }
|
---|
1564 | #endif
|
---|
1565 | hostnamelen = strlen(hostname);
|
---|
1566 | if (hostnamelen >= DNS_MAX_NAME_LENGTH) {
|
---|
1567 | LWIP_DEBUGF(DNS_DEBUG, ("dns_gethostbyname: name too long to resolve"));
|
---|
1568 | return ERR_ARG;
|
---|
1569 | }
|
---|
1570 |
|
---|
1571 |
|
---|
1572 | #if LWIP_HAVE_LOOPIF
|
---|
1573 | if (strcmp(hostname, "localhost") == 0) {
|
---|
1574 | ip_addr_set_loopback(LWIP_DNS_ADDRTYPE_IS_IPV6(dns_addrtype), addr);
|
---|
1575 | return ERR_OK;
|
---|
1576 | }
|
---|
1577 | #endif /* LWIP_HAVE_LOOPIF */
|
---|
1578 |
|
---|
1579 | /* host name already in octet notation? set ip addr and return ERR_OK */
|
---|
1580 | if (ipaddr_aton(hostname, addr)) {
|
---|
1581 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1582 | if ((IP_IS_V6(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV4)) ||
|
---|
1583 | (IP_IS_V4(addr) && (dns_addrtype != LWIP_DNS_ADDRTYPE_IPV6)))
|
---|
1584 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1585 | {
|
---|
1586 | return ERR_OK;
|
---|
1587 | }
|
---|
1588 | }
|
---|
1589 | /* already have this address cached? */
|
---|
1590 | if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)) == ERR_OK) {
|
---|
1591 | return ERR_OK;
|
---|
1592 | }
|
---|
1593 | #if LWIP_IPV4 && LWIP_IPV6
|
---|
1594 | if ((dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) || (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV6_IPV4)) {
|
---|
1595 | /* fallback to 2nd IP type and try again to lookup */
|
---|
1596 | u8_t fallback;
|
---|
1597 | if (dns_addrtype == LWIP_DNS_ADDRTYPE_IPV4_IPV6) {
|
---|
1598 | fallback = LWIP_DNS_ADDRTYPE_IPV6;
|
---|
1599 | } else {
|
---|
1600 | fallback = LWIP_DNS_ADDRTYPE_IPV4;
|
---|
1601 | }
|
---|
1602 | if (dns_lookup(hostname, addr LWIP_DNS_ADDRTYPE_ARG(fallback)) == ERR_OK) {
|
---|
1603 | return ERR_OK;
|
---|
1604 | }
|
---|
1605 | }
|
---|
1606 | #else /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1607 | LWIP_UNUSED_ARG(dns_addrtype);
|
---|
1608 | #endif /* LWIP_IPV4 && LWIP_IPV6 */
|
---|
1609 |
|
---|
1610 | #if LWIP_DNS_SUPPORT_MDNS_QUERIES
|
---|
1611 | if (strstr(hostname, ".local") == &hostname[hostnamelen] - 6) {
|
---|
1612 | is_mdns = 1;
|
---|
1613 | } else {
|
---|
1614 | is_mdns = 0;
|
---|
1615 | }
|
---|
1616 |
|
---|
1617 | if (!is_mdns)
|
---|
1618 | #endif /* LWIP_DNS_SUPPORT_MDNS_QUERIES */
|
---|
1619 | {
|
---|
1620 | /* prevent calling found callback if no server is set, return error instead */
|
---|
1621 | if (ip_addr_isany_val(dns_servers[0])) {
|
---|
1622 | return ERR_VAL;
|
---|
1623 | }
|
---|
1624 | }
|
---|
1625 |
|
---|
1626 | /* queue query with specified callback */
|
---|
1627 | return dns_enqueue(hostname, hostnamelen, found, callback_arg LWIP_DNS_ADDRTYPE_ARG(dns_addrtype)
|
---|
1628 | LWIP_DNS_ISMDNS_ARG(is_mdns));
|
---|
1629 | }
|
---|
1630 |
|
---|
1631 | #endif /* LWIP_DNS */
|
---|