577
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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4 */
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5
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6
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7 #include <ngx_config.h>
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8 #include <ngx_core.h>
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9 #include <ngx_http.h>
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10
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11
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595
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12 #define NGX_HTTP_REFERER_NO_URI_PART ((void *) 4)
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13
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577
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14 typedef struct {
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593
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15 ngx_hash_t hash;
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16 ngx_hash_wildcard_t *dns_wildcards;
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577
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17
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593
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18 ngx_flag_t no_referer;
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19 ngx_flag_t blocked_referer;
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577
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20
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593
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21 ngx_hash_keys_arrays_t *keys;
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577
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22 } ngx_http_referer_conf_t;
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23
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24
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25 static void * ngx_http_referer_create_conf(ngx_conf_t *cf);
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26 static char * ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent,
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27 void *child);
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28 static char *ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd,
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29 void *conf);
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593
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30 static char *ngx_http_add_referer(ngx_conf_t *cf, ngx_hash_keys_arrays_t *keys,
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31 ngx_str_t *value, ngx_str_t *uri);
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32 static int ngx_libc_cdecl ngx_http_cmp_referer_wildcards(const void *one,
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33 const void *two);
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34
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35
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36 static ngx_command_t ngx_http_referer_commands[] = {
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37
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38 { ngx_string("valid_referers"),
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39 NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
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40 ngx_http_valid_referers,
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41 NGX_HTTP_LOC_CONF_OFFSET,
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42 0,
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43 NULL },
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44
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45 ngx_null_command
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46 };
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47
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48
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49 static ngx_http_module_t ngx_http_referer_module_ctx = {
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50 NULL, /* preconfiguration */
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51 NULL, /* postconfiguration */
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52
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53 NULL, /* create main configuration */
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54 NULL, /* init main configuration */
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55
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56 NULL, /* create server configuration */
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57 NULL, /* merge server configuration */
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58
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59 ngx_http_referer_create_conf, /* create location configuration */
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60 ngx_http_referer_merge_conf /* merge location configuration */
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61 };
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62
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63
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64 ngx_module_t ngx_http_referer_module = {
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65 NGX_MODULE_V1,
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66 &ngx_http_referer_module_ctx, /* module context */
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67 ngx_http_referer_commands, /* module directives */
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68 NGX_HTTP_MODULE, /* module type */
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69 NULL, /* init master */
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70 NULL, /* init module */
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71 NULL, /* init process */
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72 NULL, /* init thread */
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73 NULL, /* exit thread */
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74 NULL, /* exit process */
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75 NULL, /* exit master */
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76 NGX_MODULE_V1_PADDING
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77 };
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78
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79
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80 static ngx_int_t
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81 ngx_http_referer_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v,
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82 uintptr_t data)
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83 {
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84 u_char *p, *ref, *last;
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85 size_t len;
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595
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86 ngx_str_t *uri;
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87 ngx_uint_t i, key;
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88 ngx_http_referer_conf_t *rlcf;
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89 u_char buf[256];
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90
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593
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91 rlcf = ngx_http_get_module_loc_conf(r, ngx_http_referer_module);
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92
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593
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93 if (rlcf->hash.buckets == NULL
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94 && rlcf->dns_wildcards == NULL
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95 && rlcf->dns_wildcards->hash.buckets == NULL)
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96 {
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97 goto valid;
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98 }
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99
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100 if (r->headers_in.referer == NULL) {
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101 if (rlcf->no_referer) {
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102 goto valid;
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103 }
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104
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105 goto invalid;
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106 }
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107
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108 len = r->headers_in.referer->value.len;
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109 ref = r->headers_in.referer->value.data;
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110
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111 if (len < sizeof("http://i.ru") - 1
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112 || (ngx_strncasecmp(ref, "http://", 7) != 0))
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113 {
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114 if (rlcf->blocked_referer) {
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115 goto valid;
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116 }
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117
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118 goto invalid;
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119 }
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120
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121 last = ref + len;
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122 ref += 7;
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123 i = 0;
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124 key = 0;
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125
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126 for (p = ref; p < last; p++) {
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127 if (*p == '/' || *p == ':') {
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128 break;
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129 }
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130
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131 buf[i] = ngx_tolower(*p);
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132 key = ngx_hash(key, buf[i++]);
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133
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134 if (i == 256) {
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135 goto invalid;
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136 }
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137 }
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138
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139 len = p - ref;
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140
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141 if (rlcf->hash.buckets) {
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142 uri = ngx_hash_find(&rlcf->hash, key, buf, len);
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143 if (uri) {
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144 goto uri;
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145 }
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146 }
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147
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148 if (rlcf->dns_wildcards && rlcf->dns_wildcards->hash.buckets) {
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149 uri = ngx_hash_find_wildcard(rlcf->dns_wildcards, buf, len);
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150 if (uri) {
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151 goto uri;
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152 }
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153 }
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154
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155 invalid:
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156
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157 *v = ngx_http_variable_true_value;
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158
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159 return NGX_OK;
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160
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161 uri:
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162
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163 for ( /* void */ ; p < last; p++) {
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164 if (*p == '/') {
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165 break;
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166 }
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167 }
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168
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169 len = last - p;
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170
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171 if (uri == NGX_HTTP_REFERER_NO_URI_PART) {
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172 goto valid;
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173 }
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174
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175 if (len < uri->len || ngx_strncmp(uri->data, p, uri->len) != 0) {
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176 goto invalid;
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177 }
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178
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179 valid:
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180
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181 *v = ngx_http_variable_null_value;
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182
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183 return NGX_OK;
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184 }
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185
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186
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187 static void *
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188 ngx_http_referer_create_conf(ngx_conf_t *cf)
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189 {
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190 ngx_http_referer_conf_t *conf;
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191
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192 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_referer_conf_t));
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193 if (conf == NULL) {
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194 return NGX_CONF_ERROR;
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195 }
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196
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197 conf->no_referer = NGX_CONF_UNSET;
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198 conf->blocked_referer = NGX_CONF_UNSET;
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199
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200 return conf;
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201 }
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202
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203
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204 static char *
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205 ngx_http_referer_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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206 {
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207 ngx_http_referer_conf_t *prev = parent;
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208 ngx_http_referer_conf_t *conf = child;
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209
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210 ngx_hash_init_t hash;
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211
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212 if (conf->keys == NULL) {
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213 conf->hash = prev->hash;
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214 conf->dns_wildcards = prev->dns_wildcards;
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215
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216 ngx_conf_merge_value(conf->no_referer, prev->no_referer, 0);
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217 ngx_conf_merge_value(conf->blocked_referer, prev->blocked_referer, 0);
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218
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219 return NGX_CONF_OK;
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220 }
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221
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222 hash.key = ngx_hash_key_lc;
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223 hash.max_size = 2048; /* TODO: referer_hash_max_size; */
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224 hash.bucket_size = 64; /* TODO: referer_hash_bucket_size; */
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225 hash.name = "referers_hash";
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226 hash.pool = cf->pool;
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227
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228 if (conf->keys->keys.nelts) {
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229 hash.hash = &conf->hash;
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230 hash.temp_pool = NULL;
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231
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232 if (ngx_hash_init(&hash, conf->keys->keys.elts, conf->keys->keys.nelts)
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233 != NGX_OK)
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234 {
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235 return NGX_CONF_ERROR;
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236 }
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237 }
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238
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239 if (conf->keys->dns_wildcards.nelts) {
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240
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241 ngx_qsort(conf->keys->dns_wildcards.elts,
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242 (size_t) conf->keys->dns_wildcards.nelts,
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243 sizeof(ngx_hash_key_t),
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244 ngx_http_cmp_referer_wildcards);
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245
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246 hash.hash = NULL;
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247 hash.temp_pool = cf->temp_pool;
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248
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249 if (ngx_hash_wildcard_init(&hash, conf->keys->dns_wildcards.elts,
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250 conf->keys->dns_wildcards.nelts)
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251 != NGX_OK)
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252 {
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253 return NGX_CONF_ERROR;
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254 }
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255
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256 conf->dns_wildcards = (ngx_hash_wildcard_t *) hash.hash;
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257 }
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258
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259 if (conf->no_referer == NGX_CONF_UNSET) {
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260 conf->no_referer = 0;
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261 }
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262
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263 if (conf->blocked_referer == NGX_CONF_UNSET) {
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264 conf->blocked_referer = 0;
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265 }
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266
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267 return NGX_CONF_OK;
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268 }
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269
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270
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271 static char *
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272 ngx_http_valid_referers(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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273 {
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274 ngx_http_referer_conf_t *rlcf = conf;
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275
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276 u_char *p;
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277 ngx_str_t *value, uri, name;
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278 ngx_uint_t i, n;
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279 ngx_http_variable_t *var;
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280 ngx_http_server_name_t *sn;
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281 ngx_http_core_srv_conf_t *cscf;
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282
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283 name.len = sizeof("invalid_referer") - 1;
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284 name.data = (u_char *) "invalid_referer";
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285
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286 var = ngx_http_add_variable(cf, &name,
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287 NGX_HTTP_VAR_CHANGABLE|NGX_HTTP_VAR_NOHASH);
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288 if (var == NULL) {
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289 return NGX_CONF_ERROR;
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290 }
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291
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292 var->handler = ngx_http_referer_variable;
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293
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294 if (rlcf->keys == NULL) {
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295 rlcf->keys = ngx_pcalloc(cf->temp_pool, sizeof(ngx_hash_keys_arrays_t));
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296 if (rlcf->keys == NULL) {
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297 return NGX_CONF_ERROR;
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298 }
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299
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300 rlcf->keys->pool = cf->pool;
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301 rlcf->keys->temp_pool = cf->pool;
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302
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303 if (ngx_hash_keys_array_init(rlcf->keys, NGX_HASH_SMALL) != NGX_OK) {
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304 return NGX_CONF_ERROR;
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305 }
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306 }
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307
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308 value = cf->args->elts;
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309
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310 for (i = 1; i < cf->args->nelts; i++) {
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311 if (value[i].len == 0) {
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312 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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313 "invalid referer \"%V\"", &value[i]);
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314 return NGX_CONF_ERROR;
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315 }
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316
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317 if (ngx_strcmp(value[i].data, "none") == 0) {
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318 rlcf->no_referer = 1;
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319 continue;
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320 }
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321
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322 if (ngx_strcmp(value[i].data, "blocked") == 0) {
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323 rlcf->blocked_referer = 1;
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324 continue;
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325 }
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326
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327 uri.len = 0;
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328
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329 if (ngx_strcmp(value[i].data, "server_names") == 0) {
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330
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331 cscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_core_module);
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332
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333 sn = cscf->server_names.elts;
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334 for (n = 0; n < cscf->server_names.nelts; n++) {
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335 if (ngx_http_add_referer(cf, rlcf->keys, &sn[n].name, &uri)
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336 != NGX_OK)
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337 {
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338 return NGX_CONF_ERROR;
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339 }
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340 }
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341
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342 continue;
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343 }
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344
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345 p = (u_char *) ngx_strstr(value[i].data, "/");
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346
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347 if (p) {
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348 uri.len = (value[i].data + value[i].len) - p;
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349 uri.data = p;
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350 value[i].len = p - value[i].data;
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351 }
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352
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353 if (ngx_http_add_referer(cf, rlcf->keys, &value[i], &uri) != NGX_OK) {
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354 return NGX_CONF_ERROR;
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355 }
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356 }
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357
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358 return NGX_CONF_OK;
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359 }
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360
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361
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362 static char *
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363 ngx_http_add_referer(ngx_conf_t *cf, ngx_hash_keys_arrays_t *keys,
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364 ngx_str_t *value, ngx_str_t *uri)
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593
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365 {
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366 u_char ch;
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367 ngx_int_t rc;
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368 ngx_str_t *u;
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369 ngx_uint_t flags;
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370
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371 ch = value->data[0];
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372
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373 if ((ch == '*' && (value->len < 3 || value->data[1] != '.'))
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374 || (ch == '.' && value->len < 2))
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375 {
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376 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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377 "invalid DNS wildcard \"%V\"", value);
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378
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379 return NGX_CONF_ERROR;
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380 }
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381
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382 flags = (ch == '*' || ch == '.') ? NGX_HASH_WILDCARD_KEY : 0;
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383
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595
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384 if (uri->len == 0) {
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385 u = NGX_HTTP_REFERER_NO_URI_PART;
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386
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387 } else {
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388 u = ngx_palloc(cf->pool, sizeof(ngx_str_t));
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389 if (u == NULL) {
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390 return NGX_CONF_ERROR;
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391 }
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392
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393 *u = *uri;
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394 }
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395
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396 rc = ngx_hash_add_key(keys, value, u, flags);
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593
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397
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398 if (rc == NGX_OK) {
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399 return NGX_CONF_OK;
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400 }
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401
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402 if (rc == NGX_BUSY) {
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403 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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404 "conflicting parameter \"%V\"", value);
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405 }
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406
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407 return NGX_CONF_ERROR;
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408 }
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409
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410
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411 static int ngx_libc_cdecl
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412 ngx_http_cmp_referer_wildcards(const void *one, const void *two)
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413 {
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414 ngx_hash_key_t *first, *second;
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415
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416 first = (ngx_hash_key_t *) one;
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417 second = (ngx_hash_key_t *) two;
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418
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419 return ngx_strcmp(first->key.data, second->key.data);
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420 }
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