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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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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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242 ngx_http_limit_zone_node_t *lzn, *lznt;
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243
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244 for ( ;; ) {
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245
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246 if (node->key < temp->key) {
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247
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248 if (temp->left == sentinel) {
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249 temp->left = node;
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250 break;
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251 }
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252
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253 temp = temp->left;
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254
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255 } else if (node->key > temp->key) {
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256
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257 if (temp->right == sentinel) {
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258 temp->right = node;
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259 break;
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260 }
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261
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262 temp = temp->right;
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263
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264 } else { /* node->key == temp->key */
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265
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266 lzn = (ngx_http_limit_zone_node_t *) &node->color;
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267 lznt = (ngx_http_limit_zone_node_t *) &temp->color;
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268
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269 if (ngx_memn2cmp(lzn->data, lznt->data, lzn->len, lznt->len) < 0) {
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270
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271 if (temp->left == sentinel) {
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272 temp->left = node;
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273 break;
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274 }
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275
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276 temp = temp->left;
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277
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278 } else {
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279
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280 if (temp->right == sentinel) {
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281 temp->right = node;
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282 break;
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283 }
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284
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285 temp = temp->right;
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286 }
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287 }
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288 }
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289
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290 node->parent = temp;
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291 node->left = sentinel;
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292 node->right = sentinel;
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293 ngx_rbt_red(node);
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294 }
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295
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296
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297 static void
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272
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298 ngx_http_limit_zone_cleanup(void *data)
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299 {
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300 ngx_http_limit_zone_cleanup_t *lzcln = data;
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301
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302 ngx_slab_pool_t *shpool;
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303 ngx_rbtree_node_t *node;
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304 ngx_http_limit_zone_ctx_t *ctx;
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305 ngx_http_limit_zone_node_t *lz;
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306
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307 ctx = lzcln->shm_zone->data;
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308 shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
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309 node = lzcln->node;
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310 lz = (ngx_http_limit_zone_node_t *) &node->color;
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311
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312 ngx_shmtx_lock(&shpool->mutex);
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313
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314 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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315 "limit zone cleanup: %08XD %d", node->key, lz->conn);
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316
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317 lz->conn--;
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318
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319 if (lz->conn == 0) {
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320 ngx_rbtree_delete(ctx->rbtree, node);
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321 ngx_slab_free_locked(shpool, node);
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322 }
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323
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324 ngx_shmtx_unlock(&shpool->mutex);
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325 }
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326
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327
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328 static ngx_int_t
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329 ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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330 {
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331 ngx_http_limit_zone_ctx_t *octx = data;
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332
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333 ngx_slab_pool_t *shpool;
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334 ngx_rbtree_node_t *sentinel;
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335 ngx_http_limit_zone_ctx_t *ctx;
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336
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337 ctx = shm_zone->data;
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338
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339 if (octx) {
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340 if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
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341 ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
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274
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342 "limit_zone \"%V\" uses the \"%V\" variable "
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272
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343 "while previously it used the \"%V\" variable",
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344 &shm_zone->name, &ctx->var, &octx->var);
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345 return NGX_ERROR;
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346 }
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347
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348 ctx->rbtree = octx->rbtree;
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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 shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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354
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355 ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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356 if (ctx->rbtree == NULL) {
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357 return NGX_ERROR;
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358 }
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359
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360 sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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361 if (sentinel == NULL) {
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362 return NGX_ERROR;
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363 }
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364
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365 ngx_rbtree_sentinel_init(sentinel);
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366
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367 ctx->rbtree->root = sentinel;
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368 ctx->rbtree->sentinel = sentinel;
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274
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369 ctx->rbtree->insert = ngx_http_limit_zone_rbtree_insert_value;
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272
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370
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371 return NGX_OK;
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372 }
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373
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374
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375 static void *
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376 ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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377 {
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378 ngx_http_limit_zone_conf_t *conf;
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379
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380 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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381 if (conf == NULL) {
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382 return NGX_CONF_ERROR;
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383 }
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384
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385 /*
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386 * set by ngx_pcalloc():
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387 *
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388 * conf->shm_zone = NULL;
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389 * conf->conn = 0;
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390 */
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391
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392 return conf;
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393 }
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394
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395
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396 static char *
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397 ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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398 {
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399 ngx_http_limit_zone_conf_t *prev = parent;
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400 ngx_http_limit_zone_conf_t *conf = child;
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401
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402 if (conf->shm_zone == NULL) {
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403 *conf = *prev;
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404 }
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405
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406 return NGX_CONF_OK;
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407 }
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408
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409
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410 static char *
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411 ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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412 {
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413 ssize_t n;
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414 ngx_str_t *value;
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415 ngx_shm_zone_t *shm_zone;
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416 ngx_http_limit_zone_ctx_t *ctx;
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417
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418 value = cf->args->elts;
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419
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420 if (value[2].data[0] != '$') {
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421 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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422 "invalid variable name \"%V\"", &value[2]);
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423 return NGX_CONF_ERROR;
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424 }
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425
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426 value[2].len--;
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427 value[2].data++;
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428
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429 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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430 if (ctx == NULL) {
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431 return NGX_CONF_ERROR;
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432 }
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433
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434 ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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435 if (ctx->index == NGX_ERROR) {
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436 return NGX_CONF_ERROR;
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437 }
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438
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439 ctx->var = value[2];
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440
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441 n = ngx_parse_size(&value[3]);
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442
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443 if (n == NGX_ERROR) {
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444 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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445 "invalid size of limit_zone \"%V\"", &value[3]);
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|
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446 return NGX_CONF_ERROR;
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|
|
447 }
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|
|
448
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|
|
449 if (n < (ngx_int_t) (8 * ngx_pagesize)) {
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|
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450 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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|
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451 "limit_zone \"%V\" is too small", &value[1]);
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|
|
452 return NGX_CONF_ERROR;
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|
|
453 }
|
|
|
454
|
|
|
455
|
|
|
456 shm_zone = ngx_shared_memory_add(cf, &value[1], n,
|
|
|
457 &ngx_http_limit_zone_module);
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|
|
458 if (shm_zone == NULL) {
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|
|
459 return NGX_CONF_ERROR;
|
|
|
460 }
|
|
|
461
|
|
|
462 if (shm_zone->data) {
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|
|
463 ctx = shm_zone->data;
|
|
|
464
|
|
|
465 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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|
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466 "limit_zone \"%V\" is already bound to variable \"%V\"",
|
|
|
467 &value[1], &ctx->var);
|
|
|
468 return NGX_CONF_ERROR;
|
|
|
469 }
|
|
|
470
|
|
|
471 shm_zone->init = ngx_http_limit_zone_init_zone;
|
|
|
472 shm_zone->data = ctx;
|
|
|
473
|
|
|
474 return NGX_CONF_OK;
|
|
|
475 }
|
|
|
476
|
|
|
477
|
|
|
478 static char *
|
|
|
479 ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
|
|
|
480 {
|
|
|
481 ngx_http_limit_zone_conf_t *lzcf = conf;
|
|
|
482
|
|
|
483 ngx_int_t n;
|
|
|
484 ngx_str_t *value;
|
|
|
485
|
|
|
486 value = cf->args->elts;
|
|
|
487
|
|
|
488 lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
|
|
|
489 &ngx_http_limit_zone_module);
|
|
|
490 if (lzcf->shm_zone == NULL) {
|
|
|
491 return NGX_CONF_ERROR;
|
|
|
492 }
|
|
|
493
|
|
|
494 n = ngx_atoi(value[2].data, value[2].len);
|
|
|
495 if (n <= 0) {
|
|
|
496 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
|
497 "invalid number of connections \"%V\"", &value[2]);
|
|
|
498 return NGX_CONF_ERROR;
|
|
|
499 }
|
|
|
500
|
|
274
|
501 if (n > 65535) {
|
|
|
502 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
|
503 "connection limit must be less 65536");
|
|
|
504 return NGX_CONF_ERROR;
|
|
|
505 }
|
|
|
506
|
|
272
|
507 lzcf->conn = n;
|
|
|
508
|
|
|
509 return NGX_CONF_OK;
|
|
|
510 }
|
|
|
511
|
|
|
512
|
|
|
513 static ngx_int_t
|
|
|
514 ngx_http_limit_zone_init(ngx_conf_t *cf)
|
|
|
515 {
|
|
|
516 ngx_http_handler_pt *h;
|
|
|
517 ngx_http_core_main_conf_t *cmcf;
|
|
|
518
|
|
|
519 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
|
|
|
520
|
|
|
521 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
|
|
|
522 if (h == NULL) {
|
|
|
523 return NGX_ERROR;
|
|
|
524 }
|
|
|
525
|
|
|
526 *h = ngx_http_limit_zone_handler;
|
|
|
527
|
|
|
528 return NGX_OK;
|
|
|
529 }
|
