1 | /* $Id: hostres.c 59203 2015-12-21 17:21:56Z vboxsync $ */
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2 | /** @file
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3 | * Host resolver
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2009-2015 Oracle Corporation
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8 | *
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9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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10 | * available from http://www.virtualbox.org. This file is free software;
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11 | * you can redistribute it and/or modify it under the terms of the GNU
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12 | * General Public License (GPL) as published by the Free Software
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13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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16 | */
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17 |
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18 | #ifndef RT_OS_WINDOWS
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19 | # include <netdb.h>
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20 | #endif
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21 | #include <iprt/ctype.h>
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22 | #include <iprt/assert.h>
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23 | #include <slirp.h>
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24 |
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25 | #define isdigit(ch) RT_C_IS_DIGIT(ch)
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26 | #define isalpha(ch) RT_C_IS_ALPHA(ch)
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27 |
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28 | #define DNS_CONTROL_PORT_NUMBER 53
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29 | /* see RFC 1035(4.1.1) */
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30 | struct dnsmsg_header
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31 | {
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32 | uint16_t id;
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33 |
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34 | /* XXX: endianness */
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35 | uint16_t rd:1;
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36 | uint16_t tc:1;
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37 | uint16_t aa:1;
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38 | uint16_t opcode:4;
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39 | uint16_t qr:1;
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40 | uint16_t rcode:4;
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41 | uint16_t Z:3;
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42 | uint16_t ra:1;
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43 |
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44 | uint16_t qdcount;
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45 | uint16_t ancount;
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46 | uint16_t nscount;
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47 | uint16_t arcount;
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48 | };
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49 | AssertCompileSize(struct dnsmsg_header, 12);
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50 |
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51 | #define QR_Query 0
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52 | #define QR_Response 1
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53 |
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54 | #define OpCode_Query 0
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55 |
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56 | #define RCode_NoError 0
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57 | #define RCode_FormErr 1
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58 | #define RCode_ServFail 2
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59 | #define RCode_NXDomain 3
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60 | #define RCode_NotImp 4
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61 | #define RCode_Refused 5
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62 |
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63 | #define Type_A 1
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64 | #define Type_CNAME 5
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65 | #define Type_PTR 12
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66 | #define Type_ANY 255
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67 |
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68 | #define Class_IN 1
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69 | #define Class_ANY 255
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70 |
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71 | /* compressed label encoding */
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72 | #define DNS_LABEL_PTR 0xc0
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73 |
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74 | #define DNS_MAX_UDP_LEN 512
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75 | #define DNS_MAX_LABEL_LEN 63
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76 | #define DNS_MAX_NAME_LEN 255
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77 |
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78 |
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79 | /*
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80 | * A tree of labels.
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81 | *
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82 | * rfc1035#section-3.1
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83 | * rfc1035#section-4.1.4
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84 | */
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85 | struct label
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86 | {
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87 | const uint8_t *buf;
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88 | ssize_t off;
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89 | struct label *children;
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90 | struct label *sibling;
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91 | };
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92 |
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93 |
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94 | /*
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95 | * A structure to build DNS response.
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96 | */
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97 | struct response
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98 | {
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99 | struct label *labels; /* already encoded in buf */
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100 | size_t qlen; /* original question */
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101 | size_t end; /* of data in buf */
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102 |
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103 | /* continuous buffer to build the response */
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104 | uint8_t buf[DNS_MAX_UDP_LEN];
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105 | };
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106 |
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107 |
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108 | static int verify_header(PNATState pData, struct mbuf **pMBuf);
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109 | static struct mbuf *respond(PNATState pData, struct mbuf *m, struct response *res);
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110 | struct mbuf *resolve(PNATState pData, struct mbuf *m, struct response *res,
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111 | uint16_t qtype, size_t qname);
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112 | struct mbuf *resolve_reverse(PNATState pData, struct mbuf *m, struct response *res,
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113 | uint16_t qtype, size_t qname, struct in_addr addr);
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114 | struct mbuf *refuse(PNATState pData, struct mbuf *m, unsigned int rcode);
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115 | static ssize_t append_a(struct response *res, const char *name, struct in_addr addr);
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116 | static ssize_t append_cname(struct response *res, const char *name, const char *cname);
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117 | static ssize_t append_ptr(struct response *res, const char *inaddrname, const char *name);
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118 | static ssize_t append_name_rr(struct response *res, const char *question, int type, const char *answer);
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119 | static ssize_t append_rrhdr(struct response *res, const char *name, uint16_t type, uint32_t ttl);
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120 | static ssize_t append_name(struct response *res, const char *name);
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121 | static ssize_t append_u32(struct response *res, uint32_t value);
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122 | static ssize_t append_u16(struct response *res, uint16_t value);
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123 | static ssize_t append_u8(struct response *res, uint8_t value);
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124 | static ssize_t append_bytes(struct response *res, uint8_t *p, size_t size);
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125 | static ssize_t check_space(struct response *res, size_t size);
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126 |
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127 | static int get_in_addr_arpa(struct in_addr *paddr, struct label *root);
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128 | static int labelstrcmp(struct label *l, const char *s);
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129 | static void strnlabels(char *namebuf, size_t nbuflen, const uint8_t *msg, size_t off);
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130 |
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131 | static void LogLabelsTree(const char *before, struct label *l, const char *after);
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132 | static void free_labels(struct label *root);
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133 |
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134 | #ifdef VBOX_WITH_DNSMAPPING_IN_HOSTRESOLVER
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135 | static void alterHostentWithDataFromDNSMap(PNATState pData, struct hostent *pHostent);
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136 | #endif
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137 |
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138 | #if 1 /* XXX */
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139 | # define LogErr(args) Log2(args)
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140 | # define LogDbg(args) Log3(args)
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141 | #else
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142 | # define LogErr(args) LogRel(args)
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143 | # define LogDbg(args) LogRel(args)
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144 | #endif
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145 |
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146 |
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147 | struct mbuf *
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148 | hostresolver(PNATState pData, struct mbuf *m)
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149 | {
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150 | int error;
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151 |
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152 | struct response res;
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153 |
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154 | error = verify_header(pData, &m);
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155 | if (error != 0)
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156 | return m;
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157 |
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158 | RT_ZERO(res);
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159 |
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160 | /*
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161 | * Do the real work
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162 | */
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163 | m = respond(pData, m, &res);
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164 |
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165 | free_labels(res.labels);
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166 | return m;
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167 | }
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168 |
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169 |
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170 | struct mbuf *
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171 | refuse(PNATState pData, struct mbuf *m, unsigned int rcode)
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172 | {
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173 | struct dnsmsg_header *pHdr;
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174 |
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175 | pHdr = mtod(m, struct dnsmsg_header *);
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176 | pHdr->qr = QR_Response;
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177 | pHdr->rcode = rcode;
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178 | pHdr->ra = 1;
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179 | pHdr->aa = 0;
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180 |
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181 | return m;
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182 | }
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183 |
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184 |
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185 | static int
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186 | verify_header(PNATState pData, struct mbuf **pMBuf)
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187 | {
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188 | struct mbuf *m;
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189 | struct dnsmsg_header *pHdr;
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190 | size_t mlen;
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191 |
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192 | m = *pMBuf;
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193 |
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194 | /*
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195 | * In theory we should have called
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196 | *
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197 | * m = m_pullup(m, sizeof(struct dnsmsg_header));
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198 | *
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199 | * here first (which should have been a nop), but the way mbufs
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200 | * are used in NAT will always cause a copy that will have no
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201 | * leading space. We can use m_copyup() instead, but if we are
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202 | * peeking under the hood anyway, we might as well just rely on
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203 | * the fact that this header will be contiguous.
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204 | */
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205 | pHdr = mtod(m, struct dnsmsg_header *);
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206 |
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207 | if (RT_UNLIKELY(pHdr->qr != QR_Query))
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208 | {
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209 | LogErr(("NAT: hostres: unexpected response\n"));
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210 | goto drop;
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211 | }
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212 |
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213 | mlen = m_length(m, NULL);
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214 | if (RT_UNLIKELY(mlen > DNS_MAX_UDP_LEN))
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215 | {
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216 | LogErr(("NAT: hostres: packet too large\n"));
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217 | refuse(pData, m, RCode_FormErr); /* or drop? */
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218 | return 1;
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219 | }
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220 |
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221 | if (RT_UNLIKELY(pHdr->opcode != OpCode_Query))
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222 | {
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223 | LogErr(("NAT: hostres: unsupported opcode\n"));
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224 | refuse(pData, m, RCode_NotImp);
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225 | return 1;
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226 | }
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227 |
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228 | if (RT_UNLIKELY(pHdr->qdcount != RT_H2N_U16_C(1)))
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229 | {
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230 | LogErr(("NAT: hostres: multiple questions\n"));
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231 | refuse(pData, m, RCode_NotImp);
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232 | return 1;
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233 | }
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234 |
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235 | if (RT_UNLIKELY(pHdr->ancount != 0))
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236 | {
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237 | LogErr(("NAT: hostres: answers in query\n"));
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238 | refuse(pData, m, RCode_NotImp);
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239 | return 1;
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240 | }
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241 |
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242 | if (RT_UNLIKELY(mlen < sizeof(*pHdr)
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243 | + /* qname */ 1
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244 | + /* qtype */ 2
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245 | + /* qclass */ 2))
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246 | {
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247 | LogErr(("NAT: hostres: packet too small\n"));
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248 | refuse(pData, m, RCode_FormErr);
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249 | return 1;
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250 | }
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251 |
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252 | return 0;
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253 |
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254 | drop:
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255 | if (m != NULL)
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256 | m_freem(pData, m);
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257 | *pMBuf = NULL;
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258 | return 1;
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259 | }
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260 |
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261 |
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262 | static struct mbuf *
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263 | respond(PNATState pData, struct mbuf *m, struct response *res)
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264 | {
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265 | struct dnsmsg_header *pHdr;
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266 | size_t mlen;
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267 | size_t off;
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268 | size_t qname;
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269 | uint16_t qtype, qclass;
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270 | struct in_addr in_addr_arpa;
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271 | struct label *l;
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272 |
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273 | /**
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274 | * Copy the request into the contiguous buffer for the response
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275 | * and parse the question.
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276 | */
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277 |
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278 | mlen = m_length(m, NULL);
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279 | m_copydata(m, 0, mlen, (char *)res->buf);
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280 | res->end = res->qlen = mlen;
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281 |
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282 | /* convert header to response */
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283 | pHdr = (struct dnsmsg_header *)res->buf;
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284 | pHdr->qr = QR_Response;
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285 | pHdr->rcode = RCode_NoError;
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286 | pHdr->ra = 1; /* the host provides recursion */
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287 | pHdr->aa = 0; /* we are not authoritative */
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288 | pHdr->Z = 0; /* clear rfc2535 dnssec bits */
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289 |
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290 | off = sizeof(*pHdr);
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291 | qname = off;
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292 |
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293 | /*
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294 | * Parse/verify QNAME and collect the suffixes to be used for
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295 | * compression in the answer.
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296 | */
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297 | while (off < mlen) {
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298 | size_t loff, llen;
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299 | uint8_t c;
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300 |
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301 | c = res->buf[off];
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302 |
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303 | /*
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304 | * There's just one question with just one name, so there are
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305 | * no other labels it can point to. Thus all well-formed
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306 | * names with a pointer can only be infinite loops.
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307 | */
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308 | if ((c & DNS_LABEL_PTR) == DNS_LABEL_PTR)
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309 | {
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310 | LogErr(("NAT: hostres: label pointer in the qname\n"));
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311 | return refuse(pData, m, RCode_FormErr);
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312 | }
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313 |
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314 | if ((c & DNS_LABEL_PTR) != 0)
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315 | {
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316 | LogErr(("NAT: hostres: unexpected high bits\n"));
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317 | return refuse(pData, m, RCode_FormErr);
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318 | }
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319 |
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320 | /*
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321 | * label of "llen" chars starts at offset "loff".
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322 | */
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323 | loff = off;
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324 | llen = c;
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325 | ++off;
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326 |
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327 | if (loff + 1 + llen > mlen)
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328 | {
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329 | LogErr(("NAT: hostres: length byte points beyound packet boundary\n"));
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330 | return refuse(pData, m, RCode_FormErr);
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331 | }
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332 |
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333 | if (llen == 0) /* end of the label list */
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334 | {
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335 | break;
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336 | }
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337 |
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338 | /* do only minimal verification of the label */
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339 | while (off < loff + 1 + llen)
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340 | {
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341 | c = res->buf[off];
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342 | ++off;
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343 |
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344 | if (c == '.')
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345 | {
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346 | LogErr(("NAT: hostres: dot inside label\n"));
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347 | return refuse(pData, m, RCode_FormErr);
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348 | }
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349 |
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350 | if (c == '\0')
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351 | {
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352 | LogErr(("NAT: hostres: nul byte inside label\n"));
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353 | return refuse(pData, m, RCode_FormErr);
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354 | }
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355 | }
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356 |
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357 | l = RTMemAllocZ(sizeof(*l));
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358 | l->buf = res->buf;
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359 | l->off = loff;
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360 | l->children = res->labels;
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361 | res->labels = l;
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362 | }
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363 |
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364 | /*
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365 | * QTYPE and QCLASS
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366 | */
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367 | if (RT_UNLIKELY(off + 4 > mlen))
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368 | {
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369 | LogErr(("NAT: hostres: question too short\n"));
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370 | return refuse(pData, m, RCode_FormErr);
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371 | }
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372 |
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373 | memcpy(&qtype, &res->buf[off], sizeof(qtype));
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374 | qtype = RT_N2H_U16(qtype);
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375 | off += sizeof(qtype);
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376 |
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377 | memcpy(&qclass, &res->buf[off], sizeof(qclass));
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378 | qclass = RT_N2H_U16(qclass);
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379 | off += sizeof(qclass);
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380 |
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381 | if ( qclass != Class_IN
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382 | && qclass != Class_ANY)
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383 | {
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384 | LogErr(("NAT: hostres: unsupported qclass %d\n", qclass));
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385 | return refuse(pData, m, RCode_NotImp);
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386 | }
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387 |
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388 | if ( qtype != Type_A
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389 | && qtype != Type_CNAME
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390 | && qtype != Type_PTR
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391 | && qtype != Type_ANY)
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392 | {
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393 | LogErr(("NAT: hostres: unsupported qtype %d\n", qtype));
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394 | return refuse(pData, m, RCode_NotImp);
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395 | }
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396 |
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397 |
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398 | /**
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399 | * Check if there's anything after the question. If query says it
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400 | * has authority or additional records, ignore and drop them
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401 | * without parsing.
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402 | *
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403 | * We have already rejected queries with answer(s) before. We
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404 | * have ensured that qname in the question doesn't contain
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405 | * pointers, so truncating the buffer is safe.
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406 | */
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407 | if (off < mlen)
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408 | {
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409 | int trailer = mlen - off;
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410 |
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411 | LogDbg(("NAT: hostres: question %zu < mlen %zu\n", off, mlen));
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412 |
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413 | if (pHdr->nscount == 0 && pHdr->arcount == 0)
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414 | {
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415 | LogErr(("NAT: hostres: unexpected %d bytes after the question\n", trailer));
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416 | return refuse(pData, m, RCode_FormErr);
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417 | }
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418 |
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419 | LogDbg(("NAT: hostres: ignoring %d bytes of %s%s%s records\n",
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420 | trailer,
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421 | pHdr->nscount != 0 ? "authority" : "",
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422 | pHdr->nscount != 0 && pHdr->arcount != 0 ? " and " : "",
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423 | pHdr->arcount != 0 ? "additional" : ""));
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424 |
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425 | m_adj(m, -trailer);
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426 | mlen -= trailer;
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427 | res->end = res->qlen = mlen;
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428 |
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429 | pHdr->nscount = 0;
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430 | pHdr->arcount = 0;
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431 | }
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432 |
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433 |
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434 | /*
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435 | * Check for IN-ADDR.ARPA. Use the fact that res->labels at this
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436 | * point contains only the qname, so we have easy top-down access
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437 | * to its components.
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438 | */
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439 | if (get_in_addr_arpa(&in_addr_arpa, res->labels))
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440 | return resolve_reverse(pData, m, res, qtype, qname, in_addr_arpa);
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441 | else
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442 | return resolve(pData, m, res, qtype, qname);
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443 | }
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444 |
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445 |
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446 | struct mbuf *
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447 | resolve(PNATState pData, struct mbuf *m, struct response *res,
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448 | uint16_t qtype, size_t qname)
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449 | {
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450 | struct dnsmsg_header *pHdr;
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451 | struct hostent *h;
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452 | size_t oend;
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453 | size_t nanswers;
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454 | ssize_t nbytes;
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455 | int i;
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456 |
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457 | char name[DNS_MAX_NAME_LEN+1];
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458 |
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459 | pHdr = (struct dnsmsg_header *)res->buf;
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460 | nanswers = 0;
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461 | oend = res->end;
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462 |
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463 | strnlabels(name, sizeof(name), res->buf, qname);
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464 | LogDbg(("NAT: hostres: qname=\"%s\"\n", name));
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465 |
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466 | if (qtype != Type_A && qtype != Type_CNAME && qtype != Type_ANY)
|
---|
467 | {
|
---|
468 | goto out; /* NB: RCode_NoError without an answer, not RCode_NXDomain */
|
---|
469 | }
|
---|
470 |
|
---|
471 |
|
---|
472 | h = gethostbyname(name);
|
---|
473 | if (h == NULL)
|
---|
474 | {
|
---|
475 | /* LogErr: h_errno */
|
---|
476 | return refuse(pData, m, RCode_NXDomain);
|
---|
477 | }
|
---|
478 |
|
---|
479 | #ifdef VBOX_WITH_DNSMAPPING_IN_HOSTRESOLVER
|
---|
480 | if (!LIST_EMPTY(&pData->DNSMapHead))
|
---|
481 | alterHostentWithDataFromDNSMap(pData, h);
|
---|
482 | #endif
|
---|
483 |
|
---|
484 | /*
|
---|
485 | * Emit CNAME record if canonical name differs from the qname.
|
---|
486 | */
|
---|
487 | if ( h->h_name != NULL
|
---|
488 | && RTStrICmp(h->h_name, name) != 0)
|
---|
489 | {
|
---|
490 | LogDbg(("NAT: hostres: %s CNAME %s\n", name, h->h_name));
|
---|
491 | nbytes = append_cname(res, name, h->h_name);
|
---|
492 | if (nbytes > 0)
|
---|
493 | {
|
---|
494 | ++nanswers;
|
---|
495 | }
|
---|
496 | else
|
---|
497 | {
|
---|
498 | LogErr(("NAT: hostres: failed to add %s CNAME %s\n",
|
---|
499 | name, h->h_name));
|
---|
500 | if (nbytes < 0)
|
---|
501 | return refuse(pData, m, RCode_ServFail);
|
---|
502 | else
|
---|
503 | {
|
---|
504 | pHdr->tc = 1;
|
---|
505 | goto out;
|
---|
506 | }
|
---|
507 | }
|
---|
508 |
|
---|
509 | /*
|
---|
510 | * rfc1034#section-3.6.2 - ... a type CNAME or * query should
|
---|
511 | * return just the CNAME.
|
---|
512 | */
|
---|
513 | if (qtype == Type_CNAME || qtype == Type_ANY)
|
---|
514 | goto out;
|
---|
515 | }
|
---|
516 | else if (qtype == Type_CNAME)
|
---|
517 | {
|
---|
518 | LogErr(("NAT: hostres: %s is already canonical\n", name));
|
---|
519 | goto out; /* NB: RCode_NoError without an answer, not RCode_NXDomain */
|
---|
520 | }
|
---|
521 |
|
---|
522 | /*
|
---|
523 | * Emit A records.
|
---|
524 | */
|
---|
525 | for (i = 0; h->h_addr_list[i] != NULL; ++i)
|
---|
526 | {
|
---|
527 | const char *cname = h->h_name ? h->h_name : name;
|
---|
528 | struct in_addr addr;
|
---|
529 |
|
---|
530 | addr.s_addr = *(uint32_t *)h->h_addr_list[i];
|
---|
531 | nbytes = append_a(res, cname, addr);
|
---|
532 |
|
---|
533 | if (nbytes > 0)
|
---|
534 | {
|
---|
535 | ++nanswers;
|
---|
536 | }
|
---|
537 | else
|
---|
538 | {
|
---|
539 | LogErr(("NAT: hostres: failed to add %s A %RTnaipv4\n",
|
---|
540 | cname, addr.s_addr));
|
---|
541 | if (nbytes < 0)
|
---|
542 | return refuse(pData, m, RCode_ServFail);
|
---|
543 | else
|
---|
544 | {
|
---|
545 | pHdr->tc = 1;
|
---|
546 | goto out;
|
---|
547 | }
|
---|
548 | }
|
---|
549 | }
|
---|
550 |
|
---|
551 | #if 0
|
---|
552 | /*
|
---|
553 | * It's not clear what to do with h_aliases.
|
---|
554 | *
|
---|
555 | * For names from the DNS it seems to contain the chain of CNAMEs,
|
---|
556 | * starting with the original qname from the question. So for
|
---|
557 | * them we'd need to reply with a chain of:
|
---|
558 | *
|
---|
559 | * h_aliases[i] CNAME h_aliases[i+1]
|
---|
560 | *
|
---|
561 | * OTOH, for the names from the hosts file it seems to contain all
|
---|
562 | * the names except the first one (which is considered primary and
|
---|
563 | * is reported as h_name). In which case the reply should be:
|
---|
564 | *
|
---|
565 | * h_aliases[i] CNAME h_name
|
---|
566 | *
|
---|
567 | * Obviously, we have no idea how the name was resolved, so we
|
---|
568 | * generate at most one CNAME for h_host (if differs) and ignore
|
---|
569 | * aliases altogehter.
|
---|
570 | */
|
---|
571 | for (i = 0; h->h_aliases[i] != NULL; ++i)
|
---|
572 | {
|
---|
573 | LogDbg(("NAT: hostres: ... %s\n", h->h_aliases[i]));
|
---|
574 | }
|
---|
575 | #endif
|
---|
576 |
|
---|
577 | out:
|
---|
578 | if (nanswers > 0)
|
---|
579 | {
|
---|
580 | int ok = m_append(pData, m, res->end - oend, (caddr_t)&res->buf[oend]);
|
---|
581 | if (!ok)
|
---|
582 | {
|
---|
583 | /* XXX: this may fail part way: restore old lenght, clear TC? */
|
---|
584 | return refuse(pData, m, RCode_ServFail);
|
---|
585 | }
|
---|
586 | pHdr->ancount = RT_H2N_U16(nanswers);
|
---|
587 | }
|
---|
588 | memcpy(mtod(m, char *), res->buf, sizeof(struct dnsmsg_header));
|
---|
589 | return m;
|
---|
590 | }
|
---|
591 |
|
---|
592 |
|
---|
593 | struct mbuf *
|
---|
594 | resolve_reverse(PNATState pData, struct mbuf *m, struct response *res,
|
---|
595 | uint16_t qtype, size_t qname, struct in_addr in_addr_arpa)
|
---|
596 | {
|
---|
597 | struct dnsmsg_header *pHdr;
|
---|
598 | struct hostent *h;
|
---|
599 | size_t oend;
|
---|
600 | size_t nanswers;
|
---|
601 | ssize_t nbytes;
|
---|
602 | int i;
|
---|
603 |
|
---|
604 | pHdr = (struct dnsmsg_header *)res->buf;
|
---|
605 | nanswers = 0;
|
---|
606 | oend = res->end;
|
---|
607 |
|
---|
608 | LogDbg(("NAT: hostres: %RTnaipv4\n", in_addr_arpa.s_addr));
|
---|
609 |
|
---|
610 | if (qtype != Type_PTR && qtype != Type_ANY)
|
---|
611 | {
|
---|
612 | /* can't answer CNAME to PTR queries using gethostby* */
|
---|
613 | goto out; /* NB: RCode_NoError without an answer, not RCode_NXDomain */
|
---|
614 | }
|
---|
615 |
|
---|
616 | /* XXX: TODO: apply HostResolverMappings */
|
---|
617 | h = gethostbyaddr(&in_addr_arpa, sizeof(struct in_addr), AF_INET);
|
---|
618 | if (h == NULL)
|
---|
619 | {
|
---|
620 | /* LogErr: h_errno */
|
---|
621 | return refuse(pData, m, RCode_NXDomain);
|
---|
622 | }
|
---|
623 |
|
---|
624 | if (h->h_name != NULL)
|
---|
625 | {
|
---|
626 | char name[DNS_MAX_NAME_LEN+1];
|
---|
627 | strnlabels(name, sizeof(name), res->buf, qname);
|
---|
628 |
|
---|
629 | LogDbg(("NAT: hostres: %s PTR %s\n", name, h->h_name));
|
---|
630 | nbytes = append_ptr(res, name, h->h_name);
|
---|
631 | if (nbytes > 0)
|
---|
632 | {
|
---|
633 | ++nanswers;
|
---|
634 | }
|
---|
635 | else
|
---|
636 | {
|
---|
637 | LogErr(("NAT: hostres: failed to add %s PTR %s\n",
|
---|
638 | name, h->h_name));
|
---|
639 | if (nbytes < 0)
|
---|
640 | return refuse(pData, m, RCode_ServFail);
|
---|
641 | else
|
---|
642 | {
|
---|
643 | pHdr->tc = 1;
|
---|
644 | goto out;
|
---|
645 | }
|
---|
646 | }
|
---|
647 | }
|
---|
648 |
|
---|
649 | out:
|
---|
650 | if (nanswers > 0)
|
---|
651 | {
|
---|
652 | int ok = m_append(pData, m, res->end - oend, (caddr_t)&res->buf[oend]);
|
---|
653 | if (!ok)
|
---|
654 | {
|
---|
655 | /* XXX: this may fail part way: restore old lenght, clear TC? */
|
---|
656 | return refuse(pData, m, RCode_ServFail);
|
---|
657 | }
|
---|
658 | pHdr->ancount = RT_H2N_U16(nanswers);
|
---|
659 | }
|
---|
660 | memcpy(mtod(m, char *), res->buf, sizeof(struct dnsmsg_header));
|
---|
661 | return m;
|
---|
662 | }
|
---|
663 |
|
---|
664 |
|
---|
665 |
|
---|
666 | #define APPEND_PROLOGUE() \
|
---|
667 | ssize_t size = -1; \
|
---|
668 | size_t oend = res->end; \
|
---|
669 | ssize_t nbytes; \
|
---|
670 | do {} while (0)
|
---|
671 |
|
---|
672 | #define CHECKED(_append) \
|
---|
673 | do { \
|
---|
674 | nbytes = (_append); \
|
---|
675 | if (RT_UNLIKELY(nbytes <= 0)) \
|
---|
676 | { \
|
---|
677 | if (nbytes == 0) \
|
---|
678 | size = 0; \
|
---|
679 | goto out; \
|
---|
680 | } \
|
---|
681 | } while (0)
|
---|
682 |
|
---|
683 | #define APPEND_EPILOGUE() \
|
---|
684 | do { \
|
---|
685 | size = res->end - oend; \
|
---|
686 | out: \
|
---|
687 | if (RT_UNLIKELY(size <= 0)) \
|
---|
688 | res->end = oend; \
|
---|
689 | return size; \
|
---|
690 | } while (0)
|
---|
691 |
|
---|
692 |
|
---|
693 | /*
|
---|
694 | * A RR - rfc1035#section-3.4.1
|
---|
695 | */
|
---|
696 | static ssize_t
|
---|
697 | append_a(struct response *res, const char *name, struct in_addr addr)
|
---|
698 | {
|
---|
699 | APPEND_PROLOGUE();
|
---|
700 |
|
---|
701 | CHECKED( append_rrhdr(res, name, Type_A, 3600) );
|
---|
702 | CHECKED( append_u16(res, RT_H2N_U16_C(sizeof(addr))) );
|
---|
703 | CHECKED( append_u32(res, addr.s_addr) );
|
---|
704 |
|
---|
705 | APPEND_EPILOGUE();
|
---|
706 | }
|
---|
707 |
|
---|
708 |
|
---|
709 | /*
|
---|
710 | * CNAME RR - rfc1035#section-3.3.1
|
---|
711 | */
|
---|
712 | static ssize_t
|
---|
713 | append_cname(struct response *res, const char *name, const char *cname)
|
---|
714 | {
|
---|
715 | return append_name_rr(res, name, Type_CNAME, cname);
|
---|
716 | }
|
---|
717 |
|
---|
718 |
|
---|
719 | /*
|
---|
720 | * PTR RR - rfc1035#section-3.3.12
|
---|
721 | */
|
---|
722 | static ssize_t
|
---|
723 | append_ptr(struct response *res, const char *inaddrname, const char *name)
|
---|
724 | {
|
---|
725 | return append_name_rr(res, inaddrname, Type_PTR, name);
|
---|
726 | }
|
---|
727 |
|
---|
728 |
|
---|
729 | static ssize_t
|
---|
730 | append_name_rr(struct response *res, const char *question,
|
---|
731 | int type, const char *answer)
|
---|
732 | {
|
---|
733 | size_t rdlpos;
|
---|
734 | uint16_t rdlength;
|
---|
735 |
|
---|
736 | APPEND_PROLOGUE();
|
---|
737 |
|
---|
738 | CHECKED( append_rrhdr(res, question, type, 3600) );
|
---|
739 |
|
---|
740 | rdlpos = res->end;
|
---|
741 | CHECKED( append_u16(res, 0) ); /* RDLENGTH placeholder */
|
---|
742 |
|
---|
743 | CHECKED( append_name(res, answer) );
|
---|
744 |
|
---|
745 | rdlength = RT_H2N_U16(nbytes);
|
---|
746 | memcpy(&res->buf[rdlpos], &rdlength, sizeof(rdlength));
|
---|
747 |
|
---|
748 | APPEND_EPILOGUE();
|
---|
749 | }
|
---|
750 |
|
---|
751 |
|
---|
752 | /*
|
---|
753 | * Append common RR header, up to but not including RDLENGTH and RDATA
|
---|
754 | * proper (rfc1035#section-3.2.1).
|
---|
755 | */
|
---|
756 | static ssize_t
|
---|
757 | append_rrhdr(struct response *res, const char *name, uint16_t type, uint32_t ttl)
|
---|
758 | {
|
---|
759 | APPEND_PROLOGUE();
|
---|
760 |
|
---|
761 | CHECKED( append_name(res, name) );
|
---|
762 | CHECKED( append_u16(res, RT_H2N_U16(type)) );
|
---|
763 | CHECKED( append_u16(res, RT_H2N_U16_C(Class_IN)) );
|
---|
764 | CHECKED( append_u32(res, RT_H2N_U32(ttl)) );
|
---|
765 |
|
---|
766 | APPEND_EPILOGUE();
|
---|
767 | }
|
---|
768 |
|
---|
769 |
|
---|
770 | static ssize_t
|
---|
771 | append_name(struct response *res, const char *name)
|
---|
772 | {
|
---|
773 | ssize_t size, nbytes;
|
---|
774 | struct label *root;
|
---|
775 | struct label *haystack, *needle;
|
---|
776 | struct label *head, **neck;
|
---|
777 | struct label *tail, **graft;
|
---|
778 | uint8_t *buf;
|
---|
779 | size_t wr, oend;
|
---|
780 | const char *s;
|
---|
781 |
|
---|
782 | size = -1;
|
---|
783 | oend = res->end;
|
---|
784 |
|
---|
785 | /**
|
---|
786 | * Split new name into a list of labels encoding it into the
|
---|
787 | * temporary buffer.
|
---|
788 | */
|
---|
789 | root = NULL;
|
---|
790 |
|
---|
791 | buf = RTMemAllocZ(strlen(name) + 1);
|
---|
792 | if (buf == NULL)
|
---|
793 | return -1;
|
---|
794 | wr = 0;
|
---|
795 |
|
---|
796 | s = name;
|
---|
797 | while (*s != '\0') {
|
---|
798 | const char *part;
|
---|
799 | size_t poff, plen;
|
---|
800 | struct label *l;
|
---|
801 |
|
---|
802 | part = s;
|
---|
803 | while (*s != '\0' && *s != '.')
|
---|
804 | ++s;
|
---|
805 |
|
---|
806 | plen = s - part;
|
---|
807 |
|
---|
808 | if (plen > DNS_MAX_LABEL_LEN)
|
---|
809 | {
|
---|
810 | LogErr(("NAT: hostres: name component too long\n"));
|
---|
811 | goto out;
|
---|
812 | }
|
---|
813 |
|
---|
814 | if (*s == '.')
|
---|
815 | {
|
---|
816 | if (plen == 0)
|
---|
817 | {
|
---|
818 | LogErr(("NAT: hostres: empty name component\n"));
|
---|
819 | goto out;
|
---|
820 | }
|
---|
821 |
|
---|
822 | ++s;
|
---|
823 | }
|
---|
824 |
|
---|
825 | poff = wr;
|
---|
826 |
|
---|
827 | buf[poff] = (uint8_t)plen; /* length byte */
|
---|
828 | ++wr;
|
---|
829 |
|
---|
830 | memcpy(&buf[wr], part, plen); /* label text */
|
---|
831 | wr += plen;
|
---|
832 |
|
---|
833 | l = RTMemAllocZ(sizeof(*l));
|
---|
834 | if (l == NULL)
|
---|
835 | goto out;
|
---|
836 |
|
---|
837 | l->buf = buf;
|
---|
838 | l->off = poff;
|
---|
839 | l->children = root;
|
---|
840 | root = l;
|
---|
841 | }
|
---|
842 |
|
---|
843 |
|
---|
844 | /**
|
---|
845 | * Search for a tail that is already encoded in the message.
|
---|
846 | */
|
---|
847 | neck = &root; /* where needle head is connected */
|
---|
848 | needle = root;
|
---|
849 |
|
---|
850 | tail = NULL; /* tail in the haystack */
|
---|
851 | graft = &res->labels;
|
---|
852 | haystack = res->labels;
|
---|
853 |
|
---|
854 | while (needle != NULL && haystack != NULL)
|
---|
855 | {
|
---|
856 | size_t nlen, hlen;
|
---|
857 |
|
---|
858 | nlen = needle->buf[needle->off];
|
---|
859 | Assert((nlen & DNS_LABEL_PTR) == 0);
|
---|
860 |
|
---|
861 | hlen = haystack->buf[haystack->off];
|
---|
862 | Assert((hlen & DNS_LABEL_PTR) == 0);
|
---|
863 |
|
---|
864 | if ( nlen == hlen
|
---|
865 | && RTStrNICmp((char *)&needle->buf[needle->off+1],
|
---|
866 | (char *)&haystack->buf[haystack->off+1],
|
---|
867 | nlen) == 0)
|
---|
868 | {
|
---|
869 | neck = &needle->children;
|
---|
870 | needle = needle->children;
|
---|
871 |
|
---|
872 | tail = haystack;
|
---|
873 | graft = &haystack->children;
|
---|
874 | haystack = haystack->children;
|
---|
875 | }
|
---|
876 | else
|
---|
877 | {
|
---|
878 | haystack = haystack->sibling;
|
---|
879 | }
|
---|
880 | }
|
---|
881 |
|
---|
882 |
|
---|
883 | /**
|
---|
884 | * Head contains (in reverse) the prefix that needs to be encoded
|
---|
885 | * and added to the haystack. Tail points to existing suffix that
|
---|
886 | * can be compressed to a pointer into the haystack.
|
---|
887 | */
|
---|
888 | head = *neck;
|
---|
889 | if (head != NULL)
|
---|
890 | {
|
---|
891 | struct label *l;
|
---|
892 | size_t nlen, pfxlen, pfxdst;
|
---|
893 |
|
---|
894 | nlen = needle->buf[head->off]; /* last component */
|
---|
895 | pfxlen = head->off + 1 + nlen; /* all prefix */
|
---|
896 | pfxdst = res->end; /* in response buffer */
|
---|
897 |
|
---|
898 | /* copy new prefix into response buffer */
|
---|
899 | nbytes = append_bytes(res, buf, pfxlen);
|
---|
900 | if (nbytes <= 0)
|
---|
901 | {
|
---|
902 | if (nbytes == 0)
|
---|
903 | size = 0;
|
---|
904 | goto out;
|
---|
905 | }
|
---|
906 |
|
---|
907 | /* adjust labels to point to the response */
|
---|
908 | for (l = head; l != NULL; l = l->children)
|
---|
909 | {
|
---|
910 | l->buf = res->buf;
|
---|
911 | l->off += pfxdst;
|
---|
912 | }
|
---|
913 |
|
---|
914 | *neck = NULL; /* decapitate */
|
---|
915 |
|
---|
916 | l = *graft; /* graft to the labels tree */
|
---|
917 | *graft = head;
|
---|
918 | head->sibling = l;
|
---|
919 | }
|
---|
920 |
|
---|
921 | if (tail == NULL)
|
---|
922 | nbytes = append_u8(res, 0);
|
---|
923 | else
|
---|
924 | nbytes = append_u16(res, RT_H2N_U16((DNS_LABEL_PTR << 8) | tail->off));
|
---|
925 | if (nbytes <= 0)
|
---|
926 | {
|
---|
927 | if (nbytes == 0)
|
---|
928 | size = 0;
|
---|
929 | goto out;
|
---|
930 | }
|
---|
931 |
|
---|
932 | size = res->end - oend;
|
---|
933 | out:
|
---|
934 | if (RT_UNLIKELY(size <= 0))
|
---|
935 | res->end = oend;
|
---|
936 | free_labels(root);
|
---|
937 | RTMemFree(buf);
|
---|
938 | return size;
|
---|
939 | }
|
---|
940 |
|
---|
941 |
|
---|
942 | static ssize_t
|
---|
943 | append_u32(struct response *res, uint32_t value)
|
---|
944 | {
|
---|
945 | return append_bytes(res, (uint8_t *)&value, sizeof(value));
|
---|
946 | }
|
---|
947 |
|
---|
948 |
|
---|
949 | static ssize_t
|
---|
950 | append_u16(struct response *res, uint16_t value)
|
---|
951 | {
|
---|
952 | return append_bytes(res, (uint8_t *)&value, sizeof(value));
|
---|
953 | }
|
---|
954 |
|
---|
955 |
|
---|
956 | static ssize_t
|
---|
957 | append_u8(struct response *res, uint8_t value)
|
---|
958 | {
|
---|
959 | return append_bytes(res, &value, sizeof(value));
|
---|
960 | }
|
---|
961 |
|
---|
962 |
|
---|
963 | static ssize_t
|
---|
964 | append_bytes(struct response *res, uint8_t *p, size_t size)
|
---|
965 | {
|
---|
966 | if (check_space(res, size) == 0)
|
---|
967 | return 0;
|
---|
968 |
|
---|
969 | memcpy(&res->buf[res->end], p, size);
|
---|
970 | res->end += size;
|
---|
971 | return size;
|
---|
972 | }
|
---|
973 |
|
---|
974 |
|
---|
975 | static ssize_t
|
---|
976 | check_space(struct response *res, size_t size)
|
---|
977 | {
|
---|
978 | if ( size > sizeof(res->buf)
|
---|
979 | || res->end > sizeof(res->buf) - size)
|
---|
980 | return 0;
|
---|
981 |
|
---|
982 | return size;
|
---|
983 | }
|
---|
984 |
|
---|
985 |
|
---|
986 | static int
|
---|
987 | get_in_addr_arpa(struct in_addr *paddr, struct label *root)
|
---|
988 | {
|
---|
989 | RTNETADDRIPV4 addr;
|
---|
990 | struct label *l;
|
---|
991 | int i;
|
---|
992 |
|
---|
993 | l = root;
|
---|
994 | if (l == NULL || labelstrcmp(l, "arpa") != 0)
|
---|
995 | return 0;
|
---|
996 |
|
---|
997 | l = l->children;
|
---|
998 | if (l == NULL || labelstrcmp(l, "in-addr") != 0)
|
---|
999 | return 0;
|
---|
1000 |
|
---|
1001 | for (i = 0; i < 4; ++i)
|
---|
1002 | {
|
---|
1003 | char buf[4];
|
---|
1004 | size_t llen;
|
---|
1005 | int rc;
|
---|
1006 | uint8_t octet;
|
---|
1007 |
|
---|
1008 | l = l->children;
|
---|
1009 | if (l == NULL)
|
---|
1010 | return 0;
|
---|
1011 |
|
---|
1012 | llen = l->buf[l->off];
|
---|
1013 | Assert((llen & DNS_LABEL_PTR) == 0);
|
---|
1014 |
|
---|
1015 | /* valid octet values are at most 3 digits */
|
---|
1016 | if (llen > 3)
|
---|
1017 | return 0;
|
---|
1018 |
|
---|
1019 | /* copy to avoid dealing with trailing bytes */
|
---|
1020 | memcpy(buf, &l->buf[l->off + 1], llen);
|
---|
1021 | buf[llen] = '\0';
|
---|
1022 |
|
---|
1023 | rc = RTStrToUInt8Full(buf, 10, &octet);
|
---|
1024 | if (rc != VINF_SUCCESS)
|
---|
1025 | return 0;
|
---|
1026 |
|
---|
1027 | addr.au8[i] = octet;
|
---|
1028 | }
|
---|
1029 |
|
---|
1030 | if (l->children != NULL)
|
---|
1031 | return 0; /* too many components */
|
---|
1032 |
|
---|
1033 | if (paddr != NULL)
|
---|
1034 | paddr->s_addr = addr.u;
|
---|
1035 |
|
---|
1036 | return 1;
|
---|
1037 | }
|
---|
1038 |
|
---|
1039 |
|
---|
1040 | /*
|
---|
1041 | * Compare label with string.
|
---|
1042 | */
|
---|
1043 | static int
|
---|
1044 | labelstrcmp(struct label *l, const char *s)
|
---|
1045 | {
|
---|
1046 | size_t llen;
|
---|
1047 |
|
---|
1048 | llen = l->buf[l->off];
|
---|
1049 | Assert((llen & DNS_LABEL_PTR) == 0);
|
---|
1050 |
|
---|
1051 | return RTStrNICmp((char *)&l->buf[l->off + 1], s, llen);
|
---|
1052 | }
|
---|
1053 |
|
---|
1054 |
|
---|
1055 | /*
|
---|
1056 | * Convert a chain of labels to a C string.
|
---|
1057 | *
|
---|
1058 | * I'd rather use a custom formatter for e.g. %R[label] , but it needs
|
---|
1059 | * two arguments and microsoft VC doesn't support compound literals.
|
---|
1060 | */
|
---|
1061 | static void
|
---|
1062 | strnlabels(char *namebuf, size_t nbuflen, const uint8_t *msg, size_t off)
|
---|
1063 | {
|
---|
1064 | size_t cb;
|
---|
1065 | size_t llen;
|
---|
1066 |
|
---|
1067 | namebuf[0] = '\0';
|
---|
1068 | cb = 0;
|
---|
1069 |
|
---|
1070 | llen = 0;
|
---|
1071 |
|
---|
1072 | while (cb < nbuflen - 1) {
|
---|
1073 | llen = msg[off];
|
---|
1074 | if ((llen & DNS_LABEL_PTR) == DNS_LABEL_PTR)
|
---|
1075 | {
|
---|
1076 | off = ((llen & ~DNS_LABEL_PTR) << 8) | msg[off + 1];
|
---|
1077 | llen = msg[off];
|
---|
1078 | }
|
---|
1079 |
|
---|
1080 | /* pointers to pointers should not happen */
|
---|
1081 | if ((llen & DNS_LABEL_PTR) != 0)
|
---|
1082 | {
|
---|
1083 | cb += RTStrPrintf(namebuf + cb, nbuflen - cb, "[???]");
|
---|
1084 | return;
|
---|
1085 | }
|
---|
1086 |
|
---|
1087 | if (llen == 0)
|
---|
1088 | {
|
---|
1089 | if (namebuf[0] == '\0')
|
---|
1090 | cb += RTStrPrintf(namebuf + cb, nbuflen - cb, ".");
|
---|
1091 | break;
|
---|
1092 | }
|
---|
1093 |
|
---|
1094 | if (namebuf[0] != '\0')
|
---|
1095 | cb += RTStrPrintf(namebuf + cb, nbuflen - cb, ".");
|
---|
1096 |
|
---|
1097 | cb += RTStrPrintf(namebuf + cb, nbuflen - cb,
|
---|
1098 | "%.*s", llen, (char *)&msg[off+1]);
|
---|
1099 | off = off + 1 + llen;
|
---|
1100 | }
|
---|
1101 | }
|
---|
1102 |
|
---|
1103 |
|
---|
1104 | static void
|
---|
1105 | LogLabelsTree(const char *before, struct label *l, const char *after)
|
---|
1106 | {
|
---|
1107 | size_t llen;
|
---|
1108 |
|
---|
1109 | if (before != NULL)
|
---|
1110 | LogDbg(("%s", before));
|
---|
1111 |
|
---|
1112 | if (l == NULL)
|
---|
1113 | {
|
---|
1114 | LogDbg(("NULL%s", after ? after : ""));
|
---|
1115 | return;
|
---|
1116 | }
|
---|
1117 |
|
---|
1118 | if (l->children)
|
---|
1119 | LogDbg(("("));
|
---|
1120 |
|
---|
1121 | if (l->buf != NULL)
|
---|
1122 | {
|
---|
1123 | llen = l->buf[l->off];
|
---|
1124 | if ((llen & DNS_LABEL_PTR) == 0)
|
---|
1125 | {
|
---|
1126 | LogDbg(("\"%.*s\"@%zu", llen, &l->buf[l->off+1], l->off));
|
---|
1127 | }
|
---|
1128 | else
|
---|
1129 | {
|
---|
1130 | LogDbg(("<invalid byte 0t%zu/0x%zf at offset %zd>",
|
---|
1131 | llen, llen, l->off));
|
---|
1132 | }
|
---|
1133 | }
|
---|
1134 | else
|
---|
1135 | {
|
---|
1136 | LogDbg(("<*>"));
|
---|
1137 | }
|
---|
1138 |
|
---|
1139 | if (l->children)
|
---|
1140 | LogLabelsTree(" ", l->children, ")");
|
---|
1141 |
|
---|
1142 | if (l->sibling)
|
---|
1143 | LogLabelsTree(" ", l->sibling, NULL);
|
---|
1144 |
|
---|
1145 | if (after != NULL)
|
---|
1146 | LogDbg(("%s", after));
|
---|
1147 | }
|
---|
1148 |
|
---|
1149 |
|
---|
1150 | static void
|
---|
1151 | free_labels(struct label *root)
|
---|
1152 | {
|
---|
1153 | struct label TOP; /* traverse the tree with pointer reversal */
|
---|
1154 | struct label *b, *f;
|
---|
1155 |
|
---|
1156 | if (root == NULL)
|
---|
1157 | return;
|
---|
1158 |
|
---|
1159 | RT_ZERO(TOP);
|
---|
1160 |
|
---|
1161 | b = &TOP;
|
---|
1162 | f = root;
|
---|
1163 |
|
---|
1164 | while (f != &TOP) {
|
---|
1165 | if (f->children) { /* recurse left */
|
---|
1166 | struct label *oldf = f;
|
---|
1167 | struct label *newf = f->children;
|
---|
1168 | oldf->children = b; /* reverse the pointer */
|
---|
1169 | b = oldf;
|
---|
1170 | f = newf;
|
---|
1171 | }
|
---|
1172 | else if (f->sibling) { /* turn right */
|
---|
1173 | f->children = f->sibling;
|
---|
1174 | f->sibling = NULL;
|
---|
1175 | }
|
---|
1176 | else { /* backtrack */
|
---|
1177 | struct label *oldf = f; /* garbage */
|
---|
1178 | struct label *oldb = b;
|
---|
1179 | b = oldb->children;
|
---|
1180 | oldb->children = NULL; /* oldf, but we are g/c'ing it */
|
---|
1181 | f = oldb;
|
---|
1182 |
|
---|
1183 | RTMemFree(oldf);
|
---|
1184 | }
|
---|
1185 | }
|
---|
1186 | }
|
---|
1187 |
|
---|
1188 | #ifdef VBOX_WITH_DNSMAPPING_IN_HOSTRESOLVER
|
---|
1189 | static bool isDnsMappingEntryMatchOrEqual2Str(const PDNSMAPPINGENTRY pDNSMapingEntry, const char *pcszString)
|
---|
1190 | {
|
---|
1191 | return ( ( pDNSMapingEntry->pszCName
|
---|
1192 | && !strcmp(pDNSMapingEntry->pszCName, pcszString))
|
---|
1193 | || ( pDNSMapingEntry->pszPattern
|
---|
1194 | && RTStrSimplePatternMultiMatch(pDNSMapingEntry->pszPattern, RTSTR_MAX, pcszString, RTSTR_MAX, NULL)));
|
---|
1195 | }
|
---|
1196 |
|
---|
1197 | static void alterHostentWithDataFromDNSMap(PNATState pData, struct hostent *pHostent)
|
---|
1198 | {
|
---|
1199 | PDNSMAPPINGENTRY pDNSMapingEntry = NULL;
|
---|
1200 | bool fMatch = false;
|
---|
1201 | LIST_FOREACH(pDNSMapingEntry, &pData->DNSMapHead, MapList)
|
---|
1202 | {
|
---|
1203 | char **pszAlias = NULL;
|
---|
1204 | if (isDnsMappingEntryMatchOrEqual2Str(pDNSMapingEntry, pHostent->h_name))
|
---|
1205 | {
|
---|
1206 | fMatch = true;
|
---|
1207 | break;
|
---|
1208 | }
|
---|
1209 |
|
---|
1210 | for (pszAlias = pHostent->h_aliases; *pszAlias && !fMatch; pszAlias++)
|
---|
1211 | {
|
---|
1212 | if (isDnsMappingEntryMatchOrEqual2Str(pDNSMapingEntry, *pszAlias))
|
---|
1213 | {
|
---|
1214 |
|
---|
1215 | PDNSMAPPINGENTRY pDnsMapping = RTMemAllocZ(sizeof(DNSMAPPINGENTRY));
|
---|
1216 | fMatch = true;
|
---|
1217 | if (!pDnsMapping)
|
---|
1218 | {
|
---|
1219 | LogFunc(("Can't allocate DNSMAPPINGENTRY\n"));
|
---|
1220 | LogFlowFuncLeave();
|
---|
1221 | return;
|
---|
1222 | }
|
---|
1223 | pDnsMapping->u32IpAddress = pDNSMapingEntry->u32IpAddress;
|
---|
1224 | pDnsMapping->pszCName = RTStrDup(pHostent->h_name);
|
---|
1225 | if (!pDnsMapping->pszCName)
|
---|
1226 | {
|
---|
1227 | LogFunc(("Can't allocate enough room for %s\n", pHostent->h_name));
|
---|
1228 | RTMemFree(pDnsMapping);
|
---|
1229 | LogFlowFuncLeave();
|
---|
1230 | return;
|
---|
1231 | }
|
---|
1232 | LIST_INSERT_HEAD(&pData->DNSMapHead, pDnsMapping, MapList);
|
---|
1233 | LogRel(("NAT: User-defined mapping %s: %RTnaipv4 is registered\n",
|
---|
1234 | pDnsMapping->pszCName ? pDnsMapping->pszCName : pDnsMapping->pszPattern,
|
---|
1235 | pDnsMapping->u32IpAddress));
|
---|
1236 | }
|
---|
1237 | }
|
---|
1238 | if (fMatch)
|
---|
1239 | break;
|
---|
1240 | }
|
---|
1241 |
|
---|
1242 | /* h_lenght is lenght of h_addr_list in bytes, so we check that we have enough space for IPv4 address */
|
---|
1243 | if ( fMatch
|
---|
1244 | && pHostent->h_length >= sizeof(uint32_t)
|
---|
1245 | && pDNSMapingEntry)
|
---|
1246 | {
|
---|
1247 | pHostent->h_length = 1;
|
---|
1248 | *(uint32_t *)pHostent->h_addr_list[0] = pDNSMapingEntry->u32IpAddress;
|
---|
1249 | }
|
---|
1250 |
|
---|
1251 | }
|
---|
1252 | #endif
|
---|