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) 2018 - 2019, 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 | #include "urldata.h"
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26 | #include "curl_addrinfo.h"
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27 | #include "doh.h"
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28 |
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29 | #include "sendf.h"
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30 | #include "multiif.h"
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31 | #include "url.h"
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32 | #include "share.h"
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33 | #include "curl_base64.h"
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34 | #include "connect.h"
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35 | #include "strdup.h"
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36 | /* The last 3 #include files should be in this order */
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37 | #include "curl_printf.h"
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38 | #include "curl_memory.h"
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39 | #include "memdebug.h"
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40 |
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41 | #define DNS_CLASS_IN 0x01
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42 | #define DOH_MAX_RESPONSE_SIZE 3000 /* bytes */
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43 |
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44 | #ifndef CURL_DISABLE_VERBOSE_STRINGS
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45 | static const char * const errors[]={
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46 | "",
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47 | "Bad label",
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48 | "Out of range",
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49 | "Label loop",
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50 | "Too small",
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51 | "Out of memory",
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52 | "RDATA length",
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53 | "Malformat",
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54 | "Bad RCODE",
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55 | "Unexpected TYPE",
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56 | "Unexpected CLASS",
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57 | "No content",
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58 | "Bad ID"
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59 | };
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60 |
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61 | static const char *doh_strerror(DOHcode code)
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62 | {
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63 | if((code >= DOH_OK) && (code <= DOH_DNS_BAD_ID))
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64 | return errors[code];
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65 | return "bad error code";
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66 | }
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67 | #endif
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68 |
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69 | #ifdef DEBUGBUILD
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70 | #define UNITTEST
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71 | #else
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72 | #define UNITTEST static
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73 | #endif
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74 |
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75 | UNITTEST DOHcode doh_encode(const char *host,
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76 | DNStype dnstype,
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77 | unsigned char *dnsp, /* buffer */
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78 | size_t len, /* buffer size */
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79 | size_t *olen) /* output length */
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80 | {
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81 | size_t hostlen = strlen(host);
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82 | unsigned char *orig = dnsp;
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83 | const char *hostp = host;
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84 |
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85 | if(len < (12 + hostlen + 4))
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86 | return DOH_TOO_SMALL_BUFFER;
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87 |
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88 | *dnsp++ = 0; /* 16 bit id */
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89 | *dnsp++ = 0;
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90 | *dnsp++ = 0x01; /* |QR| Opcode |AA|TC|RD| Set the RD bit */
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91 | *dnsp++ = '\0'; /* |RA| Z | RCODE | */
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92 | *dnsp++ = '\0';
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93 | *dnsp++ = 1; /* QDCOUNT (number of entries in the question section) */
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94 | *dnsp++ = '\0';
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95 | *dnsp++ = '\0'; /* ANCOUNT */
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96 | *dnsp++ = '\0';
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97 | *dnsp++ = '\0'; /* NSCOUNT */
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98 | *dnsp++ = '\0';
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99 | *dnsp++ = '\0'; /* ARCOUNT */
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100 |
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101 | /* store a QNAME */
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102 | do {
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103 | char *dot = strchr(hostp, '.');
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104 | size_t labellen;
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105 | bool found = false;
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106 | if(dot) {
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107 | found = true;
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108 | labellen = dot - hostp;
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109 | }
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110 | else
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111 | labellen = strlen(hostp);
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112 | if(labellen > 63) {
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113 | /* too long label, error out */
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114 | *olen = 0;
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115 | return DOH_DNS_BAD_LABEL;
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116 | }
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117 | *dnsp++ = (unsigned char)labellen;
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118 | memcpy(dnsp, hostp, labellen);
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119 | dnsp += labellen;
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120 | hostp += labellen + 1;
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121 | if(!found) {
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122 | *dnsp++ = 0; /* terminating zero */
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123 | break;
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124 | }
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125 | } while(1);
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126 |
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127 | *dnsp++ = '\0'; /* upper 8 bit TYPE */
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128 | *dnsp++ = (unsigned char)dnstype;
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129 | *dnsp++ = '\0'; /* upper 8 bit CLASS */
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130 | *dnsp++ = DNS_CLASS_IN; /* IN - "the Internet" */
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131 |
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132 | *olen = dnsp - orig;
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133 | return DOH_OK;
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134 | }
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135 |
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136 | static size_t
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137 | doh_write_cb(void *contents, size_t size, size_t nmemb, void *userp)
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138 | {
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139 | size_t realsize = size * nmemb;
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140 | struct dohresponse *mem = (struct dohresponse *)userp;
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141 |
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142 | if((mem->size + realsize) > DOH_MAX_RESPONSE_SIZE)
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143 | /* suspiciously much for us */
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144 | return 0;
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145 |
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146 | mem->memory = Curl_saferealloc(mem->memory, mem->size + realsize);
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147 | if(!mem->memory)
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148 | /* out of memory! */
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149 | return 0;
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150 |
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151 | memcpy(&(mem->memory[mem->size]), contents, realsize);
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152 | mem->size += realsize;
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153 |
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154 | return realsize;
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155 | }
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156 |
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157 | /* called from multi.c when this DOH transfer is complete */
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158 | static int Curl_doh_done(struct Curl_easy *doh, CURLcode result)
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159 | {
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160 | struct Curl_easy *data = doh->set.dohfor;
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161 | /* so one of the DOH request done for the 'data' transfer is now complete! */
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162 | data->req.doh.pending--;
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163 | infof(data, "a DOH request is completed, %u to go\n", data->req.doh.pending);
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164 | if(result)
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165 | infof(data, "DOH request %s\n", curl_easy_strerror(result));
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166 |
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167 | if(!data->req.doh.pending) {
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168 | /* DOH completed */
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169 | curl_slist_free_all(data->req.doh.headers);
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170 | data->req.doh.headers = NULL;
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171 | Curl_expire(data, 0, EXPIRE_RUN_NOW);
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172 | }
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173 | return 0;
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174 | }
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175 |
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176 | #define ERROR_CHECK_SETOPT(x,y) result = curl_easy_setopt(doh, x, y); \
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177 | if(result) goto error
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178 |
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179 | static CURLcode dohprobe(struct Curl_easy *data,
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180 | struct dnsprobe *p, DNStype dnstype,
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181 | const char *host,
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182 | const char *url, CURLM *multi,
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183 | struct curl_slist *headers)
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184 | {
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185 | struct Curl_easy *doh = NULL;
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186 | char *nurl = NULL;
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187 | CURLcode result = CURLE_OK;
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188 | timediff_t timeout_ms;
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189 | DOHcode d = doh_encode(host, dnstype, p->dohbuffer, sizeof(p->dohbuffer),
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190 | &p->dohlen);
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191 | if(d) {
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192 | failf(data, "Failed to encode DOH packet [%d]\n", d);
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193 | return CURLE_OUT_OF_MEMORY;
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194 | }
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195 |
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196 | p->dnstype = dnstype;
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197 | p->serverdoh.memory = NULL;
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198 | /* the memory will be grown as needed by realloc in the doh_write_cb
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199 | function */
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200 | p->serverdoh.size = 0;
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201 |
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202 | /* Note: this is code for sending the DoH request with GET but there's still
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203 | no logic that actually enables this. We should either add that ability or
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204 | yank out the GET code. Discuss! */
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205 | if(data->set.doh_get) {
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206 | char *b64;
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207 | size_t b64len;
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208 | result = Curl_base64url_encode(data, (char *)p->dohbuffer, p->dohlen,
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209 | &b64, &b64len);
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210 | if(result)
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211 | goto error;
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212 | nurl = aprintf("%s?dns=%s", url, b64);
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213 | free(b64);
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214 | if(!nurl) {
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215 | result = CURLE_OUT_OF_MEMORY;
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216 | goto error;
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217 | }
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218 | url = nurl;
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219 | }
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220 |
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221 | timeout_ms = Curl_timeleft(data, NULL, TRUE);
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222 |
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223 | /* Curl_open() is the internal version of curl_easy_init() */
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224 | result = Curl_open(&doh);
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225 | if(!result) {
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226 | /* pass in the struct pointer via a local variable to please coverity and
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227 | the gcc typecheck helpers */
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228 | struct dohresponse *resp = &p->serverdoh;
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229 | ERROR_CHECK_SETOPT(CURLOPT_URL, url);
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230 | ERROR_CHECK_SETOPT(CURLOPT_WRITEFUNCTION, doh_write_cb);
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231 | ERROR_CHECK_SETOPT(CURLOPT_WRITEDATA, resp);
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232 | if(!data->set.doh_get) {
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233 | ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDS, p->dohbuffer);
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234 | ERROR_CHECK_SETOPT(CURLOPT_POSTFIELDSIZE, (long)p->dohlen);
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235 | }
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236 | ERROR_CHECK_SETOPT(CURLOPT_HTTPHEADER, headers);
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237 | #ifdef USE_NGHTTP2
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238 | ERROR_CHECK_SETOPT(CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS);
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239 | #endif
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240 | #ifndef CURLDEBUG
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241 | /* enforce HTTPS if not debug */
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242 | ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
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243 | #endif
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244 | ERROR_CHECK_SETOPT(CURLOPT_TIMEOUT_MS, (long)timeout_ms);
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245 | ERROR_CHECK_SETOPT(CURLOPT_VERBOSE, 1L);
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246 | doh->set.fmultidone = Curl_doh_done;
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247 | doh->set.dohfor = data; /* identify for which transfer this is done */
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248 | p->easy = doh;
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249 |
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250 | /* add this transfer to the multi handle */
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251 | if(curl_multi_add_handle(multi, doh))
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252 | goto error;
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253 | }
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254 | else
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255 | goto error;
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256 | free(nurl);
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257 | return CURLE_OK;
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258 |
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259 | error:
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260 | free(nurl);
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261 | Curl_close(doh);
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262 | return result;
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263 | }
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264 |
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265 | /*
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266 | * Curl_doh() resolves a name using DOH. It resolves a name and returns a
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267 | * 'Curl_addrinfo *' with the address information.
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268 | */
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269 |
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270 | Curl_addrinfo *Curl_doh(struct connectdata *conn,
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271 | const char *hostname,
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272 | int port,
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273 | int *waitp)
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274 | {
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275 | struct Curl_easy *data = conn->data;
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276 | CURLcode result = CURLE_OK;
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277 | *waitp = TRUE; /* this never returns synchronously */
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278 | (void)conn;
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279 | (void)hostname;
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280 | (void)port;
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281 |
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282 | /* start clean, consider allocating this struct on demand */
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283 | memset(&data->req.doh, 0, sizeof(struct dohdata));
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284 |
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285 | data->req.doh.host = hostname;
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286 | data->req.doh.port = port;
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287 | data->req.doh.headers =
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288 | curl_slist_append(NULL,
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289 | "Content-Type: application/dns-message");
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290 | if(!data->req.doh.headers)
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291 | goto error;
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292 |
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293 | if(conn->ip_version != CURL_IPRESOLVE_V6) {
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294 | /* create IPv4 DOH request */
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295 | result = dohprobe(data, &data->req.doh.probe[0], DNS_TYPE_A,
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296 | hostname, data->set.str[STRING_DOH],
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297 | data->multi, data->req.doh.headers);
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298 | if(result)
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299 | goto error;
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300 | data->req.doh.pending++;
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301 | }
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302 |
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303 | if(conn->ip_version != CURL_IPRESOLVE_V4) {
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304 | /* create IPv6 DOH request */
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305 | result = dohprobe(data, &data->req.doh.probe[1], DNS_TYPE_AAAA,
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306 | hostname, data->set.str[STRING_DOH],
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307 | data->multi, data->req.doh.headers);
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308 | if(result)
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309 | goto error;
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310 | data->req.doh.pending++;
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311 | }
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312 | return NULL;
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313 |
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314 | error:
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315 | curl_slist_free_all(data->req.doh.headers);
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316 | data->req.doh.headers = NULL;
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317 | curl_easy_cleanup(data->req.doh.probe[0].easy);
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318 | data->req.doh.probe[0].easy = NULL;
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319 | curl_easy_cleanup(data->req.doh.probe[1].easy);
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320 | data->req.doh.probe[1].easy = NULL;
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321 | return NULL;
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322 | }
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323 |
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324 | static DOHcode skipqname(unsigned char *doh, size_t dohlen,
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325 | unsigned int *indexp)
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326 | {
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327 | unsigned char length;
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328 | do {
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329 | if(dohlen < (*indexp + 1))
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330 | return DOH_DNS_OUT_OF_RANGE;
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331 | length = doh[*indexp];
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332 | if((length & 0xc0) == 0xc0) {
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333 | /* name pointer, advance over it and be done */
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334 | if(dohlen < (*indexp + 2))
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335 | return DOH_DNS_OUT_OF_RANGE;
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336 | *indexp += 2;
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337 | break;
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338 | }
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339 | if(length & 0xc0)
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340 | return DOH_DNS_BAD_LABEL;
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341 | if(dohlen < (*indexp + 1 + length))
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342 | return DOH_DNS_OUT_OF_RANGE;
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343 | *indexp += 1 + length;
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344 | } while(length);
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345 | return DOH_OK;
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346 | }
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347 |
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348 | static unsigned short get16bit(unsigned char *doh, int index)
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349 | {
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350 | return (unsigned short)((doh[index] << 8) | doh[index + 1]);
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351 | }
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352 |
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353 | static unsigned int get32bit(unsigned char *doh, int index)
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354 | {
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355 | return (doh[index] << 24) | (doh[index + 1] << 16) |
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356 | (doh[index + 2] << 8) | doh[index + 3];
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357 | }
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358 |
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359 | static DOHcode store_a(unsigned char *doh, int index, struct dohentry *d)
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360 | {
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361 | /* silently ignore addresses over the limit */
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362 | if(d->numaddr < DOH_MAX_ADDR) {
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363 | struct dohaddr *a = &d->addr[d->numaddr];
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364 | a->type = DNS_TYPE_A;
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365 | memcpy(&a->ip.v4, &doh[index], 4);
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366 | d->numaddr++;
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367 | }
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368 | return DOH_OK;
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369 | }
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370 |
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371 | static DOHcode store_aaaa(unsigned char *doh, int index, struct dohentry *d)
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372 | {
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373 | /* silently ignore addresses over the limit */
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374 | if(d->numaddr < DOH_MAX_ADDR) {
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375 | struct dohaddr *a = &d->addr[d->numaddr];
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376 | a->type = DNS_TYPE_AAAA;
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377 | memcpy(&a->ip.v6, &doh[index], 16);
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378 | d->numaddr++;
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379 | }
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380 | return DOH_OK;
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381 | }
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382 |
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383 | static DOHcode cnameappend(struct cnamestore *c,
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384 | unsigned char *src,
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385 | size_t len)
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386 | {
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387 | if(!c->alloc) {
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388 | c->allocsize = len + 1;
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389 | c->alloc = malloc(c->allocsize);
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390 | if(!c->alloc)
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391 | return DOH_OUT_OF_MEM;
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392 | }
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393 | else if(c->allocsize < (c->allocsize + len + 1)) {
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394 | char *ptr;
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395 | c->allocsize += len + 1;
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396 | ptr = realloc(c->alloc, c->allocsize);
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397 | if(!ptr) {
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398 | free(c->alloc);
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399 | return DOH_OUT_OF_MEM;
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400 | }
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401 | c->alloc = ptr;
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402 | }
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403 | memcpy(&c->alloc[c->len], src, len);
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404 | c->len += len;
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405 | c->alloc[c->len] = 0; /* keep it zero terminated */
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406 | return DOH_OK;
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407 | }
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408 |
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409 | static DOHcode store_cname(unsigned char *doh,
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410 | size_t dohlen,
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411 | unsigned int index,
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412 | struct dohentry *d)
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413 | {
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414 | struct cnamestore *c;
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415 | unsigned int loop = 128; /* a valid DNS name can never loop this much */
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416 | unsigned char length;
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417 |
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418 | if(d->numcname == DOH_MAX_CNAME)
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419 | return DOH_OK; /* skip! */
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420 |
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421 | c = &d->cname[d->numcname++];
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422 | do {
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423 | if(index >= dohlen)
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424 | return DOH_DNS_OUT_OF_RANGE;
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425 | length = doh[index];
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426 | if((length & 0xc0) == 0xc0) {
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427 | int newpos;
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428 | /* name pointer, get the new offset (14 bits) */
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429 | if((index + 1) >= dohlen)
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430 | return DOH_DNS_OUT_OF_RANGE;
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431 |
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432 | /* move to the the new index */
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433 | newpos = (length & 0x3f) << 8 | doh[index + 1];
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434 | index = newpos;
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435 | continue;
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436 | }
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437 | else if(length & 0xc0)
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438 | return DOH_DNS_BAD_LABEL; /* bad input */
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439 | else
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440 | index++;
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441 |
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442 | if(length) {
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443 | DOHcode rc;
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444 | if(c->len) {
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445 | rc = cnameappend(c, (unsigned char *)".", 1);
|
---|
446 | if(rc)
|
---|
447 | return rc;
|
---|
448 | }
|
---|
449 | if((index + length) > dohlen)
|
---|
450 | return DOH_DNS_BAD_LABEL;
|
---|
451 |
|
---|
452 | rc = cnameappend(c, &doh[index], length);
|
---|
453 | if(rc)
|
---|
454 | return rc;
|
---|
455 | index += length;
|
---|
456 | }
|
---|
457 | } while(length && --loop);
|
---|
458 |
|
---|
459 | if(!loop)
|
---|
460 | return DOH_DNS_LABEL_LOOP;
|
---|
461 | return DOH_OK;
|
---|
462 | }
|
---|
463 |
|
---|
464 | static DOHcode rdata(unsigned char *doh,
|
---|
465 | size_t dohlen,
|
---|
466 | unsigned short rdlength,
|
---|
467 | unsigned short type,
|
---|
468 | int index,
|
---|
469 | struct dohentry *d)
|
---|
470 | {
|
---|
471 | /* RDATA
|
---|
472 | - A (TYPE 1): 4 bytes
|
---|
473 | - AAAA (TYPE 28): 16 bytes
|
---|
474 | - NS (TYPE 2): N bytes */
|
---|
475 | DOHcode rc;
|
---|
476 |
|
---|
477 | switch(type) {
|
---|
478 | case DNS_TYPE_A:
|
---|
479 | if(rdlength != 4)
|
---|
480 | return DOH_DNS_RDATA_LEN;
|
---|
481 | rc = store_a(doh, index, d);
|
---|
482 | if(rc)
|
---|
483 | return rc;
|
---|
484 | break;
|
---|
485 | case DNS_TYPE_AAAA:
|
---|
486 | if(rdlength != 16)
|
---|
487 | return DOH_DNS_RDATA_LEN;
|
---|
488 | rc = store_aaaa(doh, index, d);
|
---|
489 | if(rc)
|
---|
490 | return rc;
|
---|
491 | break;
|
---|
492 | case DNS_TYPE_CNAME:
|
---|
493 | rc = store_cname(doh, dohlen, index, d);
|
---|
494 | if(rc)
|
---|
495 | return rc;
|
---|
496 | break;
|
---|
497 | default:
|
---|
498 | /* unsupported type, just skip it */
|
---|
499 | break;
|
---|
500 | }
|
---|
501 | return DOH_OK;
|
---|
502 | }
|
---|
503 |
|
---|
504 | static void init_dohentry(struct dohentry *de)
|
---|
505 | {
|
---|
506 | memset(de, 0, sizeof(*de));
|
---|
507 | de->ttl = INT_MAX;
|
---|
508 | }
|
---|
509 |
|
---|
510 |
|
---|
511 | UNITTEST DOHcode doh_decode(unsigned char *doh,
|
---|
512 | size_t dohlen,
|
---|
513 | DNStype dnstype,
|
---|
514 | struct dohentry *d)
|
---|
515 | {
|
---|
516 | unsigned char rcode;
|
---|
517 | unsigned short qdcount;
|
---|
518 | unsigned short ancount;
|
---|
519 | unsigned short type = 0;
|
---|
520 | unsigned short class;
|
---|
521 | unsigned short rdlength;
|
---|
522 | unsigned short nscount;
|
---|
523 | unsigned short arcount;
|
---|
524 | unsigned int index = 12;
|
---|
525 | DOHcode rc;
|
---|
526 |
|
---|
527 | if(dohlen < 12)
|
---|
528 | return DOH_TOO_SMALL_BUFFER; /* too small */
|
---|
529 | if(!doh || doh[0] || doh[1])
|
---|
530 | return DOH_DNS_BAD_ID; /* bad ID */
|
---|
531 | rcode = doh[3] & 0x0f;
|
---|
532 | if(rcode)
|
---|
533 | return DOH_DNS_BAD_RCODE; /* bad rcode */
|
---|
534 |
|
---|
535 | qdcount = get16bit(doh, 4);
|
---|
536 | while(qdcount) {
|
---|
537 | rc = skipqname(doh, dohlen, &index);
|
---|
538 | if(rc)
|
---|
539 | return rc; /* bad qname */
|
---|
540 | if(dohlen < (index + 4))
|
---|
541 | return DOH_DNS_OUT_OF_RANGE;
|
---|
542 | index += 4; /* skip question's type and class */
|
---|
543 | qdcount--;
|
---|
544 | }
|
---|
545 |
|
---|
546 | ancount = get16bit(doh, 6);
|
---|
547 | while(ancount) {
|
---|
548 | unsigned int ttl;
|
---|
549 |
|
---|
550 | rc = skipqname(doh, dohlen, &index);
|
---|
551 | if(rc)
|
---|
552 | return rc; /* bad qname */
|
---|
553 |
|
---|
554 | if(dohlen < (index + 2))
|
---|
555 | return DOH_DNS_OUT_OF_RANGE;
|
---|
556 |
|
---|
557 | type = get16bit(doh, index);
|
---|
558 | if((type != DNS_TYPE_CNAME) && (type != dnstype))
|
---|
559 | /* Not the same type as was asked for nor CNAME */
|
---|
560 | return DOH_DNS_UNEXPECTED_TYPE;
|
---|
561 | index += 2;
|
---|
562 |
|
---|
563 | if(dohlen < (index + 2))
|
---|
564 | return DOH_DNS_OUT_OF_RANGE;
|
---|
565 | class = get16bit(doh, index);
|
---|
566 | if(DNS_CLASS_IN != class)
|
---|
567 | return DOH_DNS_UNEXPECTED_CLASS; /* unsupported */
|
---|
568 | index += 2;
|
---|
569 |
|
---|
570 | if(dohlen < (index + 4))
|
---|
571 | return DOH_DNS_OUT_OF_RANGE;
|
---|
572 |
|
---|
573 | ttl = get32bit(doh, index);
|
---|
574 | if(ttl < d->ttl)
|
---|
575 | d->ttl = ttl;
|
---|
576 | index += 4;
|
---|
577 |
|
---|
578 | if(dohlen < (index + 2))
|
---|
579 | return DOH_DNS_OUT_OF_RANGE;
|
---|
580 |
|
---|
581 | rdlength = get16bit(doh, index);
|
---|
582 | index += 2;
|
---|
583 | if(dohlen < (index + rdlength))
|
---|
584 | return DOH_DNS_OUT_OF_RANGE;
|
---|
585 |
|
---|
586 | rc = rdata(doh, dohlen, rdlength, type, index, d);
|
---|
587 | if(rc)
|
---|
588 | return rc; /* bad rdata */
|
---|
589 | index += rdlength;
|
---|
590 | ancount--;
|
---|
591 | }
|
---|
592 |
|
---|
593 | nscount = get16bit(doh, 8);
|
---|
594 | while(nscount) {
|
---|
595 | rc = skipqname(doh, dohlen, &index);
|
---|
596 | if(rc)
|
---|
597 | return rc; /* bad qname */
|
---|
598 |
|
---|
599 | if(dohlen < (index + 8))
|
---|
600 | return DOH_DNS_OUT_OF_RANGE;
|
---|
601 |
|
---|
602 | index += 2 + 2 + 4; /* type, class and ttl */
|
---|
603 |
|
---|
604 | if(dohlen < (index + 2))
|
---|
605 | return DOH_DNS_OUT_OF_RANGE;
|
---|
606 |
|
---|
607 | rdlength = get16bit(doh, index);
|
---|
608 | index += 2;
|
---|
609 | if(dohlen < (index + rdlength))
|
---|
610 | return DOH_DNS_OUT_OF_RANGE;
|
---|
611 | index += rdlength;
|
---|
612 | nscount--;
|
---|
613 | }
|
---|
614 |
|
---|
615 | arcount = get16bit(doh, 10);
|
---|
616 | while(arcount) {
|
---|
617 | rc = skipqname(doh, dohlen, &index);
|
---|
618 | if(rc)
|
---|
619 | return rc; /* bad qname */
|
---|
620 |
|
---|
621 | if(dohlen < (index + 8))
|
---|
622 | return DOH_DNS_OUT_OF_RANGE;
|
---|
623 |
|
---|
624 | index += 2 + 2 + 4; /* type, class and ttl */
|
---|
625 |
|
---|
626 | if(dohlen < (index + 2))
|
---|
627 | return DOH_DNS_OUT_OF_RANGE;
|
---|
628 |
|
---|
629 | rdlength = get16bit(doh, index);
|
---|
630 | index += 2;
|
---|
631 | if(dohlen < (index + rdlength))
|
---|
632 | return DOH_DNS_OUT_OF_RANGE;
|
---|
633 | index += rdlength;
|
---|
634 | arcount--;
|
---|
635 | }
|
---|
636 |
|
---|
637 | if(index != dohlen)
|
---|
638 | return DOH_DNS_MALFORMAT; /* something is wrong */
|
---|
639 |
|
---|
640 | if((type != DNS_TYPE_NS) && !d->numcname && !d->numaddr)
|
---|
641 | /* nothing stored! */
|
---|
642 | return DOH_NO_CONTENT;
|
---|
643 |
|
---|
644 | return DOH_OK; /* ok */
|
---|
645 | }
|
---|
646 |
|
---|
647 | #ifndef CURL_DISABLE_VERBOSE_STRINGS
|
---|
648 | static void showdoh(struct Curl_easy *data,
|
---|
649 | struct dohentry *d)
|
---|
650 | {
|
---|
651 | int i;
|
---|
652 | infof(data, "TTL: %u seconds\n", d->ttl);
|
---|
653 | for(i = 0; i < d->numaddr; i++) {
|
---|
654 | struct dohaddr *a = &d->addr[i];
|
---|
655 | if(a->type == DNS_TYPE_A) {
|
---|
656 | infof(data, "DOH A: %u.%u.%u.%u\n",
|
---|
657 | a->ip.v4[0], a->ip.v4[1],
|
---|
658 | a->ip.v4[2], a->ip.v4[3]);
|
---|
659 | }
|
---|
660 | else if(a->type == DNS_TYPE_AAAA) {
|
---|
661 | int j;
|
---|
662 | char buffer[128];
|
---|
663 | char *ptr;
|
---|
664 | size_t len;
|
---|
665 | msnprintf(buffer, 128, "DOH AAAA: ");
|
---|
666 | ptr = &buffer[10];
|
---|
667 | len = 118;
|
---|
668 | for(j = 0; j < 16; j += 2) {
|
---|
669 | size_t l;
|
---|
670 | msnprintf(ptr, len, "%s%02x%02x", j?":":"", d->addr[i].ip.v6[j],
|
---|
671 | d->addr[i].ip.v6[j + 1]);
|
---|
672 | l = strlen(ptr);
|
---|
673 | len -= l;
|
---|
674 | ptr += l;
|
---|
675 | }
|
---|
676 | infof(data, "%s\n", buffer);
|
---|
677 | }
|
---|
678 | }
|
---|
679 | for(i = 0; i < d->numcname; i++) {
|
---|
680 | infof(data, "CNAME: %s\n", d->cname[i].alloc);
|
---|
681 | }
|
---|
682 | }
|
---|
683 | #else
|
---|
684 | #define showdoh(x,y)
|
---|
685 | #endif
|
---|
686 |
|
---|
687 | /*
|
---|
688 | * doh2ai()
|
---|
689 | *
|
---|
690 | * This function returns a pointer to the first element of a newly allocated
|
---|
691 | * Curl_addrinfo struct linked list filled with the data from a set of DOH
|
---|
692 | * lookups. Curl_addrinfo is meant to work like the addrinfo struct does for
|
---|
693 | * a IPv6 stack, but usable also for IPv4, all hosts and environments.
|
---|
694 | *
|
---|
695 | * The memory allocated by this function *MUST* be free'd later on calling
|
---|
696 | * Curl_freeaddrinfo(). For each successful call to this function there
|
---|
697 | * must be an associated call later to Curl_freeaddrinfo().
|
---|
698 | */
|
---|
699 |
|
---|
700 | static Curl_addrinfo *
|
---|
701 | doh2ai(const struct dohentry *de, const char *hostname, int port)
|
---|
702 | {
|
---|
703 | Curl_addrinfo *ai;
|
---|
704 | Curl_addrinfo *prevai = NULL;
|
---|
705 | Curl_addrinfo *firstai = NULL;
|
---|
706 | struct sockaddr_in *addr;
|
---|
707 | #ifdef ENABLE_IPV6
|
---|
708 | struct sockaddr_in6 *addr6;
|
---|
709 | #endif
|
---|
710 | CURLcode result = CURLE_OK;
|
---|
711 | int i;
|
---|
712 |
|
---|
713 | if(!de)
|
---|
714 | /* no input == no output! */
|
---|
715 | return NULL;
|
---|
716 |
|
---|
717 | for(i = 0; i < de->numaddr; i++) {
|
---|
718 | size_t ss_size;
|
---|
719 | CURL_SA_FAMILY_T addrtype;
|
---|
720 | if(de->addr[i].type == DNS_TYPE_AAAA) {
|
---|
721 | #ifndef ENABLE_IPV6
|
---|
722 | /* we can't handle IPv6 addresses */
|
---|
723 | continue;
|
---|
724 | #else
|
---|
725 | ss_size = sizeof(struct sockaddr_in6);
|
---|
726 | addrtype = AF_INET6;
|
---|
727 | #endif
|
---|
728 | }
|
---|
729 | else {
|
---|
730 | ss_size = sizeof(struct sockaddr_in);
|
---|
731 | addrtype = AF_INET;
|
---|
732 | }
|
---|
733 |
|
---|
734 | ai = calloc(1, sizeof(Curl_addrinfo));
|
---|
735 | if(!ai) {
|
---|
736 | result = CURLE_OUT_OF_MEMORY;
|
---|
737 | break;
|
---|
738 | }
|
---|
739 | ai->ai_canonname = strdup(hostname);
|
---|
740 | if(!ai->ai_canonname) {
|
---|
741 | result = CURLE_OUT_OF_MEMORY;
|
---|
742 | free(ai);
|
---|
743 | break;
|
---|
744 | }
|
---|
745 | ai->ai_addr = calloc(1, ss_size);
|
---|
746 | if(!ai->ai_addr) {
|
---|
747 | result = CURLE_OUT_OF_MEMORY;
|
---|
748 | free(ai->ai_canonname);
|
---|
749 | free(ai);
|
---|
750 | break;
|
---|
751 | }
|
---|
752 |
|
---|
753 | if(!firstai)
|
---|
754 | /* store the pointer we want to return from this function */
|
---|
755 | firstai = ai;
|
---|
756 |
|
---|
757 | if(prevai)
|
---|
758 | /* make the previous entry point to this */
|
---|
759 | prevai->ai_next = ai;
|
---|
760 |
|
---|
761 | ai->ai_family = addrtype;
|
---|
762 |
|
---|
763 | /* we return all names as STREAM, so when using this address for TFTP
|
---|
764 | the type must be ignored and conn->socktype be used instead! */
|
---|
765 | ai->ai_socktype = SOCK_STREAM;
|
---|
766 |
|
---|
767 | ai->ai_addrlen = (curl_socklen_t)ss_size;
|
---|
768 |
|
---|
769 | /* leave the rest of the struct filled with zero */
|
---|
770 |
|
---|
771 | switch(ai->ai_family) {
|
---|
772 | case AF_INET:
|
---|
773 | addr = (void *)ai->ai_addr; /* storage area for this info */
|
---|
774 | DEBUGASSERT(sizeof(struct in_addr) == sizeof(de->addr[i].ip.v4));
|
---|
775 | memcpy(&addr->sin_addr, &de->addr[i].ip.v4, sizeof(struct in_addr));
|
---|
776 | addr->sin_family = (CURL_SA_FAMILY_T)addrtype;
|
---|
777 | addr->sin_port = htons((unsigned short)port);
|
---|
778 | break;
|
---|
779 |
|
---|
780 | #ifdef ENABLE_IPV6
|
---|
781 | case AF_INET6:
|
---|
782 | addr6 = (void *)ai->ai_addr; /* storage area for this info */
|
---|
783 | DEBUGASSERT(sizeof(struct in6_addr) == sizeof(de->addr[i].ip.v6));
|
---|
784 | memcpy(&addr6->sin6_addr, &de->addr[i].ip.v6, sizeof(struct in6_addr));
|
---|
785 | addr6->sin6_family = (CURL_SA_FAMILY_T)addrtype;
|
---|
786 | addr6->sin6_port = htons((unsigned short)port);
|
---|
787 | break;
|
---|
788 | #endif
|
---|
789 | }
|
---|
790 |
|
---|
791 | prevai = ai;
|
---|
792 | }
|
---|
793 |
|
---|
794 | if(result) {
|
---|
795 | Curl_freeaddrinfo(firstai);
|
---|
796 | firstai = NULL;
|
---|
797 | }
|
---|
798 |
|
---|
799 | return firstai;
|
---|
800 | }
|
---|
801 |
|
---|
802 | #ifndef CURL_DISABLE_VERBOSE_STRINGS
|
---|
803 | static const char *type2name(DNStype dnstype)
|
---|
804 | {
|
---|
805 | return (dnstype == DNS_TYPE_A)?"A":"AAAA";
|
---|
806 | }
|
---|
807 | #endif
|
---|
808 |
|
---|
809 | UNITTEST void de_cleanup(struct dohentry *d)
|
---|
810 | {
|
---|
811 | int i = 0;
|
---|
812 | for(i = 0; i < d->numcname; i++) {
|
---|
813 | free(d->cname[i].alloc);
|
---|
814 | }
|
---|
815 | }
|
---|
816 |
|
---|
817 | CURLcode Curl_doh_is_resolved(struct connectdata *conn,
|
---|
818 | struct Curl_dns_entry **dnsp)
|
---|
819 | {
|
---|
820 | struct Curl_easy *data = conn->data;
|
---|
821 | *dnsp = NULL; /* defaults to no response */
|
---|
822 |
|
---|
823 | if(!data->req.doh.probe[0].easy && !data->req.doh.probe[1].easy) {
|
---|
824 | failf(data, "Could not DOH-resolve: %s", conn->async.hostname);
|
---|
825 | return conn->bits.proxy?CURLE_COULDNT_RESOLVE_PROXY:
|
---|
826 | CURLE_COULDNT_RESOLVE_HOST;
|
---|
827 | }
|
---|
828 | else if(!data->req.doh.pending) {
|
---|
829 | DOHcode rc;
|
---|
830 | DOHcode rc2;
|
---|
831 | struct dohentry de;
|
---|
832 | struct Curl_dns_entry *dns;
|
---|
833 | struct Curl_addrinfo *ai;
|
---|
834 | /* remove DOH handles from multi handle and close them */
|
---|
835 | curl_multi_remove_handle(data->multi, data->req.doh.probe[0].easy);
|
---|
836 | Curl_close(data->req.doh.probe[0].easy);
|
---|
837 | curl_multi_remove_handle(data->multi, data->req.doh.probe[1].easy);
|
---|
838 | Curl_close(data->req.doh.probe[1].easy);
|
---|
839 |
|
---|
840 | /* parse the responses, create the struct and return it! */
|
---|
841 | init_dohentry(&de);
|
---|
842 | rc = doh_decode(data->req.doh.probe[0].serverdoh.memory,
|
---|
843 | data->req.doh.probe[0].serverdoh.size,
|
---|
844 | data->req.doh.probe[0].dnstype,
|
---|
845 | &de);
|
---|
846 | free(data->req.doh.probe[0].serverdoh.memory);
|
---|
847 | if(rc) {
|
---|
848 | infof(data, "DOH: %s type %s for %s\n", doh_strerror(rc),
|
---|
849 | type2name(data->req.doh.probe[0].dnstype),
|
---|
850 | data->req.doh.host);
|
---|
851 | }
|
---|
852 | rc2 = doh_decode(data->req.doh.probe[1].serverdoh.memory,
|
---|
853 | data->req.doh.probe[1].serverdoh.size,
|
---|
854 | data->req.doh.probe[1].dnstype,
|
---|
855 | &de);
|
---|
856 | free(data->req.doh.probe[1].serverdoh.memory);
|
---|
857 | if(rc2) {
|
---|
858 | infof(data, "DOH: %s type %s for %s\n", doh_strerror(rc2),
|
---|
859 | type2name(data->req.doh.probe[1].dnstype),
|
---|
860 | data->req.doh.host);
|
---|
861 | }
|
---|
862 | if(!rc || !rc2) {
|
---|
863 | infof(data, "DOH Host name: %s\n", data->req.doh.host);
|
---|
864 | showdoh(data, &de);
|
---|
865 |
|
---|
866 | ai = doh2ai(&de, data->req.doh.host, data->req.doh.port);
|
---|
867 | if(!ai) {
|
---|
868 | de_cleanup(&de);
|
---|
869 | return CURLE_OUT_OF_MEMORY;
|
---|
870 | }
|
---|
871 |
|
---|
872 | if(data->share)
|
---|
873 | Curl_share_lock(data, CURL_LOCK_DATA_DNS, CURL_LOCK_ACCESS_SINGLE);
|
---|
874 |
|
---|
875 | /* we got a response, store it in the cache */
|
---|
876 | dns = Curl_cache_addr(data, ai, data->req.doh.host, data->req.doh.port);
|
---|
877 |
|
---|
878 | if(data->share)
|
---|
879 | Curl_share_unlock(data, CURL_LOCK_DATA_DNS);
|
---|
880 |
|
---|
881 | de_cleanup(&de);
|
---|
882 | if(!dns)
|
---|
883 | /* returned failure, bail out nicely */
|
---|
884 | Curl_freeaddrinfo(ai);
|
---|
885 | else {
|
---|
886 | conn->async.dns = dns;
|
---|
887 | *dnsp = dns;
|
---|
888 | return CURLE_OK;
|
---|
889 | }
|
---|
890 | }
|
---|
891 | de_cleanup(&de);
|
---|
892 |
|
---|
893 | return CURLE_COULDNT_RESOLVE_HOST;
|
---|
894 | }
|
---|
895 |
|
---|
896 | return CURLE_OK;
|
---|
897 | }
|
---|