272
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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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12 typedef struct {
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13 u_char color;
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14 u_char len;
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15 u_short conn;
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16 u_char data[1];
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17 } ngx_http_limit_zone_node_t;
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18
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19
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20 typedef struct {
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21 ngx_shm_zone_t *shm_zone;
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22 ngx_rbtree_node_t *node;
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23 } ngx_http_limit_zone_cleanup_t;
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24
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25
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26 typedef struct {
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27 ngx_rbtree_t *rbtree;
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28 ngx_int_t index;
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29 ngx_str_t var;
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30 } ngx_http_limit_zone_ctx_t;
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31
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32
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33 typedef struct {
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34 ngx_shm_zone_t *shm_zone;
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35 ngx_uint_t conn;
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36 } ngx_http_limit_zone_conf_t;
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37
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38
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39 static void ngx_http_limit_zone_cleanup(void *data);
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40
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41 static void *ngx_http_limit_zone_create_conf(ngx_conf_t *cf);
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42 static char *ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent,
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43 void *child);
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44 static char *ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd,
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45 void *conf);
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46 static char *ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
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47 void *conf);
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48 static ngx_int_t ngx_http_limit_zone_init(ngx_conf_t *cf);
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49
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50
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51 static ngx_command_t ngx_http_limit_zone_commands[] = {
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52
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53 { ngx_string("limit_zone"),
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54 NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
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55 ngx_http_limit_zone,
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56 0,
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57 0,
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58 NULL },
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59
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60 { ngx_string("limit_conn"),
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61 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
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62 ngx_http_limit_conn,
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63 NGX_HTTP_LOC_CONF_OFFSET,
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64 0,
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65 NULL },
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66
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67 ngx_null_command
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68 };
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69
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70
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71 static ngx_http_module_t ngx_http_limit_zone_module_ctx = {
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72 NULL, /* preconfiguration */
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73 ngx_http_limit_zone_init, /* postconfiguration */
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74
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75 NULL, /* create main configuration */
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76 NULL, /* init main configuration */
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77
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78 NULL, /* create server configuration */
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79 NULL, /* merge server configuration */
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80
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81 ngx_http_limit_zone_create_conf, /* create location configration */
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82 ngx_http_limit_zone_merge_conf /* merge location configration */
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83 };
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84
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85
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86 ngx_module_t ngx_http_limit_zone_module = {
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87 NGX_MODULE_V1,
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88 &ngx_http_limit_zone_module_ctx, /* module context */
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89 ngx_http_limit_zone_commands, /* module directives */
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90 NGX_HTTP_MODULE, /* module type */
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91 NULL, /* init master */
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92 NULL, /* init module */
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93 NULL, /* init process */
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94 NULL, /* init thread */
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95 NULL, /* exit thread */
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96 NULL, /* exit process */
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97 NULL, /* exit master */
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98 NGX_MODULE_V1_PADDING
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99 };
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100
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101
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102 static ngx_int_t
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103 ngx_http_limit_zone_handler(ngx_http_request_t *r)
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104 {
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105 size_t len, n;
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106 uint32_t hash;
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274
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107 ngx_int_t rc;
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272
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108 ngx_slab_pool_t *shpool;
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109 ngx_rbtree_node_t *node, *sentinel;
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110 ngx_pool_cleanup_t *cln;
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111 ngx_http_variable_value_t *vv;
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112 ngx_http_limit_zone_ctx_t *ctx;
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113 ngx_http_limit_zone_node_t *lz;
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114 ngx_http_limit_zone_conf_t *lzcf;
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115 ngx_http_limit_zone_cleanup_t *lzcln;
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116
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117 if (r->main->limit_zone_set) {
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118 return NGX_DECLINED;
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119 }
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120
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121 lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
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122
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123 if (lzcf->shm_zone == NULL) {
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124 return NGX_DECLINED;
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125 }
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126
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127 ctx = lzcf->shm_zone->data;
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128
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129 vv = ngx_http_get_indexed_variable(r, ctx->index);
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130
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131 if (vv == NULL || vv->not_found) {
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132 return NGX_DECLINED;
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133 }
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134
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274
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135 len = vv->len;
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136
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137 if (len == 0) {
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138 return NGX_DECLINED;
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139 }
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272
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140
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274
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141 if (len > 255) {
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142 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
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143 "the value of the \"%V\" variable "
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328
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144 "is more than 255 bytes: \"%v\"",
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274
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145 &ctx->var, vv);
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146 return NGX_DECLINED;
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147 }
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148
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149 r->main->limit_zone_set = 1;
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272
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150
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151 hash = ngx_crc32_short(vv->data, len);
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152
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153 cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
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154 if (cln == NULL) {
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155 return NGX_HTTP_INTERNAL_SERVER_ERROR;
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156 }
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157
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158 shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
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159
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160 ngx_shmtx_lock(&shpool->mutex);
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161
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162 node = ctx->rbtree->root;
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163 sentinel = ctx->rbtree->sentinel;
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164
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165 while (node != sentinel) {
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166
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167 if (hash < node->key) {
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168 node = node->left;
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169 continue;
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170 }
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171
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172 if (hash > node->key) {
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173 node = node->right;
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174 continue;
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175 }
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176
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274
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177 /* hash == node->key */
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178
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179 do {
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272
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180 lz = (ngx_http_limit_zone_node_t *) &node->color;
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181
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276
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182 rc = ngx_memn2cmp(vv->data, lz->data, len, (size_t) lz->len);
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274
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183
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184 if (rc == 0) {
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272
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185 if ((ngx_uint_t) lz->conn < lzcf->conn) {
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186 lz->conn++;
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187 goto done;
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188 }
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189
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190 ngx_shmtx_unlock(&shpool->mutex);
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191
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192 return NGX_HTTP_SERVICE_UNAVAILABLE;
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193 }
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274
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194
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195 node = (rc < 0) ? node->left : node->right;
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196
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197 } while (node != sentinel && hash == node->key);
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198
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199 break;
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272
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200 }
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201
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202 n = offsetof(ngx_rbtree_node_t, color)
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203 + offsetof(ngx_http_limit_zone_node_t, data)
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204 + len;
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205
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206 node = ngx_slab_alloc_locked(shpool, n);
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207 if (node == NULL) {
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208 ngx_shmtx_unlock(&shpool->mutex);
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209 return NGX_HTTP_SERVICE_UNAVAILABLE;
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210 }
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211
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212 lz = (ngx_http_limit_zone_node_t *) &node->color;
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213
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214 node->key = hash;
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215 lz->len = (u_char) len;
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216 lz->conn = 1;
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217 ngx_memcpy(lz->data, vv->data, len);
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218
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219 ngx_rbtree_insert(ctx->rbtree, node);
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220
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221 done:
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222
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223 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
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224 "limit zone: %08XD %d", node->key, lz->conn);
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225
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226 ngx_shmtx_unlock(&shpool->mutex);
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227
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228 cln->handler = ngx_http_limit_zone_cleanup;
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229 lzcln = cln->data;
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230
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231 lzcln->shm_zone = lzcf->shm_zone;
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232 lzcln->node = node;
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233
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234 return NGX_DECLINED;
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235 }
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236
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237
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238 static void
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274
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239 ngx_http_limit_zone_rbtree_insert_value(ngx_rbtree_node_t *temp,
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240 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
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241 {
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356
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242 ngx_rbtree_node_t **p;
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243 ngx_http_limit_zone_node_t *lzn, *lznt;
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274
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244
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245 for ( ;; ) {
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246
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247 if (node->key < temp->key) {
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248
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356
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249 p = &temp->left;
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274
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250
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251 } else if (node->key > temp->key) {
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252
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356
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253 p = &temp->right;
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274
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254
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255 } else { /* node->key == temp->key */
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256
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257 lzn = (ngx_http_limit_zone_node_t *) &node->color;
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258 lznt = (ngx_http_limit_zone_node_t *) &temp->color;
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259
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356
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260 p = (ngx_memn2cmp(lzn->data, lznt->data, lzn->len, lznt->len) < 0)
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261 ? &temp->left : &temp->right;
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262 }
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274
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263
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356
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264 if (*p == sentinel) {
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265 break;
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266 }
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274
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267
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356
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268 temp = *p;
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274
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269 }
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270
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356
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271 *p = node;
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274
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272 node->parent = temp;
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273 node->left = sentinel;
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274 node->right = sentinel;
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275 ngx_rbt_red(node);
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276 }
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277
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278
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279 static void
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272
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280 ngx_http_limit_zone_cleanup(void *data)
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281 {
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282 ngx_http_limit_zone_cleanup_t *lzcln = data;
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283
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284 ngx_slab_pool_t *shpool;
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285 ngx_rbtree_node_t *node;
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286 ngx_http_limit_zone_ctx_t *ctx;
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287 ngx_http_limit_zone_node_t *lz;
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288
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289 ctx = lzcln->shm_zone->data;
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290 shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
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291 node = lzcln->node;
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292 lz = (ngx_http_limit_zone_node_t *) &node->color;
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293
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294 ngx_shmtx_lock(&shpool->mutex);
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295
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296 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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297 "limit zone cleanup: %08XD %d", node->key, lz->conn);
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298
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299 lz->conn--;
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300
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301 if (lz->conn == 0) {
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302 ngx_rbtree_delete(ctx->rbtree, node);
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303 ngx_slab_free_locked(shpool, node);
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304 }
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305
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306 ngx_shmtx_unlock(&shpool->mutex);
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307 }
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308
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309
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310 static ngx_int_t
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311 ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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312 {
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313 ngx_http_limit_zone_ctx_t *octx = data;
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314
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315 ngx_slab_pool_t *shpool;
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316 ngx_rbtree_node_t *sentinel;
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317 ngx_http_limit_zone_ctx_t *ctx;
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318
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319 ctx = shm_zone->data;
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320
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321 if (octx) {
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322 if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
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323 ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
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274
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324 "limit_zone \"%V\" uses the \"%V\" variable "
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272
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325 "while previously it used the \"%V\" variable",
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326 &shm_zone->name, &ctx->var, &octx->var);
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327 return NGX_ERROR;
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328 }
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329
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330 ctx->rbtree = octx->rbtree;
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331
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332 return NGX_OK;
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333 }
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334
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335 shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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336
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337 ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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338 if (ctx->rbtree == NULL) {
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339 return NGX_ERROR;
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340 }
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341
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342 sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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343 if (sentinel == NULL) {
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344 return NGX_ERROR;
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345 }
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346
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356
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347 ngx_rbtree_init(ctx->rbtree, sentinel,
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348 ngx_http_limit_zone_rbtree_insert_value);
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272
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349
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350 return NGX_OK;
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351 }
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352
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353
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354 static void *
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355 ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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356 {
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357 ngx_http_limit_zone_conf_t *conf;
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358
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359 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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360 if (conf == NULL) {
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361 return NGX_CONF_ERROR;
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362 }
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363
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364 /*
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365 * set by ngx_pcalloc():
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366 *
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367 * conf->shm_zone = NULL;
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368 * conf->conn = 0;
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369 */
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370
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371 return conf;
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372 }
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373
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374
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375 static char *
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376 ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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377 {
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378 ngx_http_limit_zone_conf_t *prev = parent;
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379 ngx_http_limit_zone_conf_t *conf = child;
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380
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381 if (conf->shm_zone == NULL) {
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382 *conf = *prev;
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383 }
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384
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385 return NGX_CONF_OK;
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386 }
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387
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388
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389 static char *
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390 ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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391 {
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392 ssize_t n;
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393 ngx_str_t *value;
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394 ngx_shm_zone_t *shm_zone;
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395 ngx_http_limit_zone_ctx_t *ctx;
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396
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397 value = cf->args->elts;
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398
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399 if (value[2].data[0] != '$') {
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400 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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401 "invalid variable name \"%V\"", &value[2]);
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402 return NGX_CONF_ERROR;
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403 }
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404
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405 value[2].len--;
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406 value[2].data++;
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407
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408 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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409 if (ctx == NULL) {
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410 return NGX_CONF_ERROR;
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411 }
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412
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413 ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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414 if (ctx->index == NGX_ERROR) {
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415 return NGX_CONF_ERROR;
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416 }
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417
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418 ctx->var = value[2];
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419
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420 n = ngx_parse_size(&value[3]);
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421
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422 if (n == NGX_ERROR) {
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423 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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424 "invalid size of limit_zone \"%V\"", &value[3]);
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425 return NGX_CONF_ERROR;
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426 }
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427
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428 if (n < (ngx_int_t) (8 * ngx_pagesize)) {
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429 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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430 "limit_zone \"%V\" is too small", &value[1]);
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431 return NGX_CONF_ERROR;
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432 }
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433
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434
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435 shm_zone = ngx_shared_memory_add(cf, &value[1], n,
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436 &ngx_http_limit_zone_module);
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437 if (shm_zone == NULL) {
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438 return NGX_CONF_ERROR;
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439 }
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440
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441 if (shm_zone->data) {
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442 ctx = shm_zone->data;
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443
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444 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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445 "limit_zone \"%V\" is already bound to variable \"%V\"",
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446 &value[1], &ctx->var);
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447 return NGX_CONF_ERROR;
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448 }
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449
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450 shm_zone->init = ngx_http_limit_zone_init_zone;
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451 shm_zone->data = ctx;
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452
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453 return NGX_CONF_OK;
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454 }
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455
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456
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457 static char *
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458 ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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459 {
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460 ngx_http_limit_zone_conf_t *lzcf = conf;
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461
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462 ngx_int_t n;
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463 ngx_str_t *value;
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464
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465 value = cf->args->elts;
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466
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467 lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
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468 &ngx_http_limit_zone_module);
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469 if (lzcf->shm_zone == NULL) {
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470 return NGX_CONF_ERROR;
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471 }
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472
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473 n = ngx_atoi(value[2].data, value[2].len);
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474 if (n <= 0) {
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475 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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476 "invalid number of connections \"%V\"", &value[2]);
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477 return NGX_CONF_ERROR;
|
|
478 }
|
|
479
|
274
|
480 if (n > 65535) {
|
|
481 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
482 "connection limit must be less 65536");
|
|
483 return NGX_CONF_ERROR;
|
|
484 }
|
|
485
|
272
|
486 lzcf->conn = n;
|
|
487
|
|
488 return NGX_CONF_OK;
|
|
489 }
|
|
490
|
|
491
|
|
492 static ngx_int_t
|
|
493 ngx_http_limit_zone_init(ngx_conf_t *cf)
|
|
494 {
|
|
495 ngx_http_handler_pt *h;
|
|
496 ngx_http_core_main_conf_t *cmcf;
|
|
497
|
|
498 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
|
|
499
|
|
500 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
|
|
501 if (h == NULL) {
|
|
502 return NGX_ERROR;
|
|
503 }
|
|
504
|
|
505 *h = ngx_http_limit_zone_handler;
|
|
506
|
|
507 return NGX_OK;
|
|
508 }
|