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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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107 ngx_slab_pool_t *shpool;
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108 ngx_rbtree_node_t *node, *sentinel;
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109 ngx_pool_cleanup_t *cln;
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110 ngx_http_variable_value_t *vv;
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111 ngx_http_limit_zone_ctx_t *ctx;
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112 ngx_http_limit_zone_node_t *lz;
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113 ngx_http_limit_zone_conf_t *lzcf;
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114 ngx_http_limit_zone_cleanup_t *lzcln;
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115
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116 if (r->main->limit_zone_set) {
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117 return NGX_DECLINED;
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118 }
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119
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120 lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
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121
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122 if (lzcf->shm_zone == NULL) {
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123 return NGX_DECLINED;
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124 }
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125
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126 ctx = lzcf->shm_zone->data;
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127
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128 vv = ngx_http_get_indexed_variable(r, ctx->index);
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129
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130 if (vv == NULL || vv->not_found) {
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131 return NGX_DECLINED;
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132 }
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133
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134 r->limit_zone_set = 1;
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135
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136 len = vv->len;
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137
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138 hash = ngx_crc32_short(vv->data, len);
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139
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140 cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
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141 if (cln == NULL) {
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142 return NGX_HTTP_INTERNAL_SERVER_ERROR;
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143 }
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144
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145 shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
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146
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147 ngx_shmtx_lock(&shpool->mutex);
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148
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149 node = ctx->rbtree->root;
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150 sentinel = ctx->rbtree->sentinel;
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151
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152 while (node != sentinel) {
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153
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154 if (hash < node->key) {
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155 node = node->left;
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156 continue;
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157 }
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158
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159 if (hash > node->key) {
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160 node = node->right;
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161 continue;
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162 }
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163
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164 if (hash == node->key ){
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165 lz = (ngx_http_limit_zone_node_t *) &node->color;
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166
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167 if (len == (size_t) lz->len
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168 && ngx_strncmp(lz->data, vv->data, len) == 0)
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169 {
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170 if ((ngx_uint_t) lz->conn < lzcf->conn) {
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171 lz->conn++;
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172 goto done;
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173 }
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174
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175 ngx_shmtx_unlock(&shpool->mutex);
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176
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177 return NGX_HTTP_SERVICE_UNAVAILABLE;
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178 }
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179 }
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180 }
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181
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182 n = offsetof(ngx_rbtree_node_t, color)
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183 + offsetof(ngx_http_limit_zone_node_t, data)
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184 + len;
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185
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186 node = ngx_slab_alloc_locked(shpool, n);
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187 if (node == NULL) {
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188 ngx_shmtx_unlock(&shpool->mutex);
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189 return NGX_HTTP_SERVICE_UNAVAILABLE;
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190 }
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191
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192 lz = (ngx_http_limit_zone_node_t *) &node->color;
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193
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194 node->key = hash;
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195 lz->len = (u_char) len;
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196 lz->conn = 1;
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197 ngx_memcpy(lz->data, vv->data, len);
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198
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199 ngx_rbtree_insert(ctx->rbtree, node);
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200
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201 done:
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202
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203 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
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204 "limit zone: %08XD %d", node->key, lz->conn);
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205
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206 ngx_shmtx_unlock(&shpool->mutex);
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207
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208 cln->handler = ngx_http_limit_zone_cleanup;
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209 lzcln = cln->data;
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210
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211 lzcln->shm_zone = lzcf->shm_zone;
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212 lzcln->node = node;
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213
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214 return NGX_DECLINED;
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215 }
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216
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217
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218 static void
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219 ngx_http_limit_zone_cleanup(void *data)
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220 {
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221 ngx_http_limit_zone_cleanup_t *lzcln = data;
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222
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223 ngx_slab_pool_t *shpool;
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224 ngx_rbtree_node_t *node;
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225 ngx_http_limit_zone_ctx_t *ctx;
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226 ngx_http_limit_zone_node_t *lz;
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227
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228 ctx = lzcln->shm_zone->data;
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229 shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
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230 node = lzcln->node;
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231 lz = (ngx_http_limit_zone_node_t *) &node->color;
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232
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233 ngx_shmtx_lock(&shpool->mutex);
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234
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235 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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236 "limit zone cleanup: %08XD %d", node->key, lz->conn);
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237
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238 lz->conn--;
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239
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240 if (lz->conn == 0) {
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241 ngx_rbtree_delete(ctx->rbtree, node);
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242 ngx_slab_free_locked(shpool, node);
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243 }
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244
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245 ngx_shmtx_unlock(&shpool->mutex);
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246 }
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247
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248
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249 static ngx_int_t
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250 ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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251 {
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252 ngx_http_limit_zone_ctx_t *octx = data;
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253
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254 ngx_slab_pool_t *shpool;
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255 ngx_rbtree_node_t *sentinel;
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256 ngx_http_limit_zone_ctx_t *ctx;
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257
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258 ctx = shm_zone->data;
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259
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260 if (octx) {
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261 if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
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262 ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
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263 "limit_zone \"%V\" use the \"%V\" variable "
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264 "while previously it used the \"%V\" variable",
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265 &shm_zone->name, &ctx->var, &octx->var);
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266 return NGX_ERROR;
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267 }
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268
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269 ctx->rbtree = octx->rbtree;
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270
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271 return NGX_OK;
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272 }
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273
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274 shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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275
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276 ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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277 if (ctx->rbtree == NULL) {
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278 return NGX_ERROR;
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279 }
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280
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281 sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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282 if (sentinel == NULL) {
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283 return NGX_ERROR;
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284 }
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285
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286 ngx_rbtree_sentinel_init(sentinel);
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287
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288 ctx->rbtree->root = sentinel;
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289 ctx->rbtree->sentinel = sentinel;
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290 ctx->rbtree->insert = ngx_rbtree_insert_value;
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291
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292 return NGX_OK;
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293 }
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294
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295
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296 static void *
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297 ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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298 {
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299 ngx_http_limit_zone_conf_t *conf;
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300
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301 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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302 if (conf == NULL) {
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303 return NGX_CONF_ERROR;
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304 }
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305
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306 /*
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307 * set by ngx_pcalloc():
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308 *
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309 * conf->shm_zone = NULL;
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310 * conf->conn = 0;
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311 */
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312
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313 return conf;
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314 }
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315
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316
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317 static char *
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318 ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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319 {
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320 ngx_http_limit_zone_conf_t *prev = parent;
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321 ngx_http_limit_zone_conf_t *conf = child;
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322
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323 if (conf->shm_zone == NULL) {
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324 *conf = *prev;
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325 }
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326
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327 return NGX_CONF_OK;
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328 }
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329
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330
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331 static char *
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332 ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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333 {
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334 ssize_t n;
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335 ngx_str_t *value;
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336 ngx_shm_zone_t *shm_zone;
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337 ngx_http_limit_zone_ctx_t *ctx;
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338
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339 value = cf->args->elts;
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340
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341 if (value[2].data[0] != '$') {
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342 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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343 "invalid variable name \"%V\"", &value[2]);
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344 return NGX_CONF_ERROR;
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345 }
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346
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347 value[2].len--;
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348 value[2].data++;
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349
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350 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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351 if (ctx == NULL) {
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352 return NGX_CONF_ERROR;
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353 }
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354
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355 ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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356 if (ctx->index == NGX_ERROR) {
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357 return NGX_CONF_ERROR;
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358 }
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359
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360 ctx->var = value[2];
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361
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362 n = ngx_parse_size(&value[3]);
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363
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364 if (n == NGX_ERROR) {
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365 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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366 "invalid size of limit_zone \"%V\"", &value[3]);
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367 return NGX_CONF_ERROR;
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368 }
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369
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370 if (n < (ngx_int_t) (8 * ngx_pagesize)) {
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371 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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372 "limit_zone \"%V\" is too small", &value[1]);
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373 return NGX_CONF_ERROR;
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374 }
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375
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376
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377 shm_zone = ngx_shared_memory_add(cf, &value[1], n,
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378 &ngx_http_limit_zone_module);
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379 if (shm_zone == NULL) {
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380 return NGX_CONF_ERROR;
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381 }
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382
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383 if (shm_zone->data) {
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384 ctx = shm_zone->data;
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385
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386 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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387 "limit_zone \"%V\" is already bound to variable \"%V\"",
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388 &value[1], &ctx->var);
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389 return NGX_CONF_ERROR;
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390 }
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391
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392 shm_zone->init = ngx_http_limit_zone_init_zone;
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393 shm_zone->data = ctx;
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394
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395 return NGX_CONF_OK;
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396 }
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397
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398
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399 static char *
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400 ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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401 {
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402 ngx_http_limit_zone_conf_t *lzcf = conf;
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403
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404 ngx_int_t n;
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405 ngx_str_t *value;
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406
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407 value = cf->args->elts;
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408
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409 lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
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410 &ngx_http_limit_zone_module);
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411 if (lzcf->shm_zone == NULL) {
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412 return NGX_CONF_ERROR;
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413 }
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414
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415 n = ngx_atoi(value[2].data, value[2].len);
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416 if (n <= 0) {
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417 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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418 "invalid number of connections \"%V\"", &value[2]);
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419 return NGX_CONF_ERROR;
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|
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420 }
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421
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422 lzcf->conn = n;
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423
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424 return NGX_CONF_OK;
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|
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425 }
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426
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427
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|
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428 static ngx_int_t
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429 ngx_http_limit_zone_init(ngx_conf_t *cf)
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|
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430 {
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431 ngx_http_handler_pt *h;
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432 ngx_http_core_main_conf_t *cmcf;
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433
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434 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
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435
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436 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
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|
|
437 if (h == NULL) {
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438 return NGX_ERROR;
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|
|
439 }
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440
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441 *h = ngx_http_limit_zone_handler;
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|
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442
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443 return NGX_OK;
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|
|
444 }
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