272
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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644
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4 * Copyright (C) Nginx, Inc.
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272
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5 */
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6
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7
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8 #include <ngx_config.h>
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9 #include <ngx_core.h>
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10 #include <ngx_http.h>
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11
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12
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13 typedef struct {
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14 u_char color;
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15 u_char len;
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16 u_short conn;
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17 u_char data[1];
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18 } ngx_http_limit_zone_node_t;
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19
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20
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21 typedef struct {
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22 ngx_shm_zone_t *shm_zone;
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23 ngx_rbtree_node_t *node;
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24 } ngx_http_limit_zone_cleanup_t;
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25
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26
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27 typedef struct {
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28 ngx_rbtree_t *rbtree;
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29 ngx_int_t index;
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30 ngx_str_t var;
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31 } ngx_http_limit_zone_ctx_t;
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32
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33
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34 typedef struct {
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35 ngx_shm_zone_t *shm_zone;
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36 ngx_uint_t conn;
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532
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37 ngx_uint_t log_level;
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272
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38 } ngx_http_limit_zone_conf_t;
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39
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40
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41 static void ngx_http_limit_zone_cleanup(void *data);
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42
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43 static void *ngx_http_limit_zone_create_conf(ngx_conf_t *cf);
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44 static char *ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent,
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45 void *child);
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46 static char *ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd,
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47 void *conf);
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48 static char *ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
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49 void *conf);
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50 static ngx_int_t ngx_http_limit_zone_init(ngx_conf_t *cf);
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51
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52
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532
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53 static ngx_conf_enum_t ngx_http_limit_conn_log_levels[] = {
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54 { ngx_string("info"), NGX_LOG_INFO },
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55 { ngx_string("notice"), NGX_LOG_NOTICE },
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56 { ngx_string("warn"), NGX_LOG_WARN },
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57 { ngx_string("error"), NGX_LOG_ERR },
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58 { ngx_null_string, 0 }
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59 };
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60
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61
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272
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62 static ngx_command_t ngx_http_limit_zone_commands[] = {
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63
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64 { ngx_string("limit_zone"),
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65 NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
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66 ngx_http_limit_zone,
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67 0,
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68 0,
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69 NULL },
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70
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71 { ngx_string("limit_conn"),
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72 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
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73 ngx_http_limit_conn,
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74 NGX_HTTP_LOC_CONF_OFFSET,
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75 0,
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76 NULL },
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77
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532
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78 { ngx_string("limit_conn_log_level"),
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79 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
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80 ngx_conf_set_enum_slot,
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81 NGX_HTTP_LOC_CONF_OFFSET,
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82 offsetof(ngx_http_limit_zone_conf_t, log_level),
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83 &ngx_http_limit_conn_log_levels },
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84
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272
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85 ngx_null_command
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86 };
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87
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88
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89 static ngx_http_module_t ngx_http_limit_zone_module_ctx = {
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90 NULL, /* preconfiguration */
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91 ngx_http_limit_zone_init, /* postconfiguration */
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92
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93 NULL, /* create main configuration */
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94 NULL, /* init main configuration */
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95
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96 NULL, /* create server configuration */
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97 NULL, /* merge server configuration */
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98
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646
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99 ngx_http_limit_zone_create_conf, /* create location configuration */
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100 ngx_http_limit_zone_merge_conf /* merge location configuration */
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272
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101 };
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102
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103
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104 ngx_module_t ngx_http_limit_zone_module = {
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105 NGX_MODULE_V1,
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106 &ngx_http_limit_zone_module_ctx, /* module context */
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107 ngx_http_limit_zone_commands, /* module directives */
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108 NGX_HTTP_MODULE, /* module type */
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109 NULL, /* init master */
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110 NULL, /* init module */
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111 NULL, /* init process */
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112 NULL, /* init thread */
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113 NULL, /* exit thread */
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114 NULL, /* exit process */
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115 NULL, /* exit master */
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116 NGX_MODULE_V1_PADDING
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117 };
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118
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119
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120 static ngx_int_t
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121 ngx_http_limit_zone_handler(ngx_http_request_t *r)
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122 {
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123 size_t len, n;
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124 uint32_t hash;
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274
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125 ngx_int_t rc;
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272
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126 ngx_slab_pool_t *shpool;
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127 ngx_rbtree_node_t *node, *sentinel;
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128 ngx_pool_cleanup_t *cln;
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129 ngx_http_variable_value_t *vv;
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130 ngx_http_limit_zone_ctx_t *ctx;
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131 ngx_http_limit_zone_node_t *lz;
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132 ngx_http_limit_zone_conf_t *lzcf;
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133 ngx_http_limit_zone_cleanup_t *lzcln;
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134
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135 if (r->main->limit_zone_set) {
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136 return NGX_DECLINED;
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137 }
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138
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139 lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
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140
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141 if (lzcf->shm_zone == NULL) {
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142 return NGX_DECLINED;
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143 }
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144
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145 ctx = lzcf->shm_zone->data;
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146
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147 vv = ngx_http_get_indexed_variable(r, ctx->index);
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148
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149 if (vv == NULL || vv->not_found) {
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150 return NGX_DECLINED;
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151 }
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152
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274
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153 len = vv->len;
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154
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155 if (len == 0) {
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156 return NGX_DECLINED;
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157 }
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272
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158
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274
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159 if (len > 255) {
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160 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
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161 "the value of the \"%V\" variable "
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328
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162 "is more than 255 bytes: \"%v\"",
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163 &ctx->var, vv);
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164 return NGX_DECLINED;
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165 }
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166
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167 r->main->limit_zone_set = 1;
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272
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168
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169 hash = ngx_crc32_short(vv->data, len);
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170
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171 cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
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172 if (cln == NULL) {
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173 return NGX_HTTP_INTERNAL_SERVER_ERROR;
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174 }
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175
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176 shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
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177
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178 ngx_shmtx_lock(&shpool->mutex);
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179
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180 node = ctx->rbtree->root;
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181 sentinel = ctx->rbtree->sentinel;
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182
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183 while (node != sentinel) {
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184
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185 if (hash < node->key) {
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186 node = node->left;
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187 continue;
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188 }
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189
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190 if (hash > node->key) {
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191 node = node->right;
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192 continue;
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193 }
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194
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274
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195 /* hash == node->key */
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196
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646
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197 lz = (ngx_http_limit_zone_node_t *) &node->color;
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272
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198
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646
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199 rc = ngx_memn2cmp(vv->data, lz->data, len, (size_t) lz->len);
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274
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200
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646
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201 if (rc == 0) {
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202 if ((ngx_uint_t) lz->conn < lzcf->conn) {
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203 lz->conn++;
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204 goto done;
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272
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205 }
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274
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206
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646
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207 ngx_shmtx_unlock(&shpool->mutex);
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208
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646
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209 ngx_log_error(lzcf->log_level, r->connection->log, 0,
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210 "limiting connections by zone \"%V\"",
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211 &lzcf->shm_zone->shm.name);
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212
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213 return NGX_HTTP_SERVICE_UNAVAILABLE;
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214 }
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215
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216 node = (rc < 0) ? node->left : node->right;
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272
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217 }
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218
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219 n = offsetof(ngx_rbtree_node_t, color)
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220 + offsetof(ngx_http_limit_zone_node_t, data)
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221 + len;
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222
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223 node = ngx_slab_alloc_locked(shpool, n);
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224 if (node == NULL) {
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225 ngx_shmtx_unlock(&shpool->mutex);
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226 return NGX_HTTP_SERVICE_UNAVAILABLE;
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227 }
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228
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229 lz = (ngx_http_limit_zone_node_t *) &node->color;
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230
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231 node->key = hash;
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232 lz->len = (u_char) len;
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233 lz->conn = 1;
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234 ngx_memcpy(lz->data, vv->data, len);
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235
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236 ngx_rbtree_insert(ctx->rbtree, node);
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237
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238 done:
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239
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240 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
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241 "limit zone: %08XD %d", node->key, lz->conn);
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242
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243 ngx_shmtx_unlock(&shpool->mutex);
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244
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245 cln->handler = ngx_http_limit_zone_cleanup;
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246 lzcln = cln->data;
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247
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248 lzcln->shm_zone = lzcf->shm_zone;
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249 lzcln->node = node;
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250
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251 return NGX_DECLINED;
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252 }
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253
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254
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255 static void
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274
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256 ngx_http_limit_zone_rbtree_insert_value(ngx_rbtree_node_t *temp,
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257 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
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258 {
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356
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259 ngx_rbtree_node_t **p;
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260 ngx_http_limit_zone_node_t *lzn, *lznt;
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274
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261
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262 for ( ;; ) {
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263
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264 if (node->key < temp->key) {
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265
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356
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266 p = &temp->left;
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274
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267
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268 } else if (node->key > temp->key) {
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269
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356
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270 p = &temp->right;
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274
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271
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272 } else { /* node->key == temp->key */
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273
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274 lzn = (ngx_http_limit_zone_node_t *) &node->color;
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275 lznt = (ngx_http_limit_zone_node_t *) &temp->color;
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276
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356
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277 p = (ngx_memn2cmp(lzn->data, lznt->data, lzn->len, lznt->len) < 0)
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278 ? &temp->left : &temp->right;
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279 }
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274
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280
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356
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281 if (*p == sentinel) {
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282 break;
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283 }
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274
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284
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356
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285 temp = *p;
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274
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286 }
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287
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356
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288 *p = node;
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274
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289 node->parent = temp;
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290 node->left = sentinel;
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291 node->right = sentinel;
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292 ngx_rbt_red(node);
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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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272
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297 ngx_http_limit_zone_cleanup(void *data)
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298 {
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299 ngx_http_limit_zone_cleanup_t *lzcln = data;
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300
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301 ngx_slab_pool_t *shpool;
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302 ngx_rbtree_node_t *node;
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303 ngx_http_limit_zone_ctx_t *ctx;
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304 ngx_http_limit_zone_node_t *lz;
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305
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306 ctx = lzcln->shm_zone->data;
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307 shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
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308 node = lzcln->node;
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309 lz = (ngx_http_limit_zone_node_t *) &node->color;
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310
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311 ngx_shmtx_lock(&shpool->mutex);
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312
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313 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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314 "limit zone cleanup: %08XD %d", node->key, lz->conn);
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315
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316 lz->conn--;
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317
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318 if (lz->conn == 0) {
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319 ngx_rbtree_delete(ctx->rbtree, node);
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320 ngx_slab_free_locked(shpool, node);
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321 }
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322
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323 ngx_shmtx_unlock(&shpool->mutex);
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324 }
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325
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326
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327 static ngx_int_t
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328 ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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329 {
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330 ngx_http_limit_zone_ctx_t *octx = data;
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331
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468
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332 size_t len;
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272
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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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480
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344 &shm_zone->shm.name, &ctx->var, &octx->var);
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272
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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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480
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355 if (shm_zone->shm.exists) {
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356 ctx->rbtree = shpool->data;
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357
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358 return NGX_OK;
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359 }
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360
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272
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361 ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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362 if (ctx->rbtree == NULL) {
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363 return NGX_ERROR;
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364 }
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365
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480
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366 shpool->data = ctx->rbtree;
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367
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272
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368 sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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369 if (sentinel == NULL) {
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370 return NGX_ERROR;
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371 }
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372
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356
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373 ngx_rbtree_init(ctx->rbtree, sentinel,
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374 ngx_http_limit_zone_rbtree_insert_value);
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272
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375
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480
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376 len = sizeof(" in limit_zone \"\"") + shm_zone->shm.name.len;
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468
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377
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378 shpool->log_ctx = ngx_slab_alloc(shpool, len);
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379 if (shpool->log_ctx == NULL) {
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380 return NGX_ERROR;
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381 }
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382
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480
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383 ngx_sprintf(shpool->log_ctx, " in limit_zone \"%V\"%Z",
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384 &shm_zone->shm.name);
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468
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385
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272
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386 return NGX_OK;
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387 }
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388
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389
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390 static void *
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391 ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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392 {
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393 ngx_http_limit_zone_conf_t *conf;
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394
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395 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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396 if (conf == NULL) {
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496
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397 return NULL;
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272
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398 }
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399
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400 /*
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401 * set by ngx_pcalloc():
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402 *
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403 * conf->shm_zone = NULL;
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404 * conf->conn = 0;
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405 */
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406
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532
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407 conf->log_level = NGX_CONF_UNSET_UINT;
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408
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272
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409 return conf;
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410 }
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411
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412
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413 static char *
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414 ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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415 {
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416 ngx_http_limit_zone_conf_t *prev = parent;
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417 ngx_http_limit_zone_conf_t *conf = child;
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418
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419 if (conf->shm_zone == NULL) {
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644
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420 conf->shm_zone = prev->shm_zone;
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421 conf->conn = prev->conn;
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272
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422 }
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423
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532
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424 ngx_conf_merge_uint_value(conf->log_level, prev->log_level, NGX_LOG_ERR);
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425
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272
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426 return NGX_CONF_OK;
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427 }
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428
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429
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430 static char *
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431 ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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432 {
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433 ssize_t n;
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434 ngx_str_t *value;
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435 ngx_shm_zone_t *shm_zone;
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436 ngx_http_limit_zone_ctx_t *ctx;
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437
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438 value = cf->args->elts;
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439
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440 if (value[2].data[0] != '$') {
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441 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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442 "invalid variable name \"%V\"", &value[2]);
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443 return NGX_CONF_ERROR;
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444 }
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445
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446 value[2].len--;
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447 value[2].data++;
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448
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449 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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450 if (ctx == NULL) {
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451 return NGX_CONF_ERROR;
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452 }
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453
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454 ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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455 if (ctx->index == NGX_ERROR) {
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456 return NGX_CONF_ERROR;
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457 }
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458
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459 ctx->var = value[2];
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460
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461 n = ngx_parse_size(&value[3]);
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462
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463 if (n == NGX_ERROR) {
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464 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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465 "invalid size of limit_zone \"%V\"", &value[3]);
|
|
466 return NGX_CONF_ERROR;
|
|
467 }
|
|
468
|
|
469 if (n < (ngx_int_t) (8 * ngx_pagesize)) {
|
|
470 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
471 "limit_zone \"%V\" is too small", &value[1]);
|
|
472 return NGX_CONF_ERROR;
|
|
473 }
|
|
474
|
|
475
|
|
476 shm_zone = ngx_shared_memory_add(cf, &value[1], n,
|
|
477 &ngx_http_limit_zone_module);
|
|
478 if (shm_zone == NULL) {
|
|
479 return NGX_CONF_ERROR;
|
|
480 }
|
|
481
|
|
482 if (shm_zone->data) {
|
|
483 ctx = shm_zone->data;
|
|
484
|
|
485 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
486 "limit_zone \"%V\" is already bound to variable \"%V\"",
|
|
487 &value[1], &ctx->var);
|
|
488 return NGX_CONF_ERROR;
|
|
489 }
|
|
490
|
|
491 shm_zone->init = ngx_http_limit_zone_init_zone;
|
|
492 shm_zone->data = ctx;
|
|
493
|
|
494 return NGX_CONF_OK;
|
|
495 }
|
|
496
|
|
497
|
|
498 static char *
|
|
499 ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
|
|
500 {
|
|
501 ngx_http_limit_zone_conf_t *lzcf = conf;
|
|
502
|
|
503 ngx_int_t n;
|
|
504 ngx_str_t *value;
|
|
505
|
426
|
506 if (lzcf->shm_zone) {
|
|
507 return "is duplicate";
|
|
508 }
|
|
509
|
272
|
510 value = cf->args->elts;
|
|
511
|
|
512 lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
|
|
513 &ngx_http_limit_zone_module);
|
|
514 if (lzcf->shm_zone == NULL) {
|
|
515 return NGX_CONF_ERROR;
|
|
516 }
|
|
517
|
|
518 n = ngx_atoi(value[2].data, value[2].len);
|
|
519 if (n <= 0) {
|
|
520 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
521 "invalid number of connections \"%V\"", &value[2]);
|
|
522 return NGX_CONF_ERROR;
|
|
523 }
|
|
524
|
274
|
525 if (n > 65535) {
|
|
526 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
527 "connection limit must be less 65536");
|
|
528 return NGX_CONF_ERROR;
|
|
529 }
|
|
530
|
272
|
531 lzcf->conn = n;
|
|
532
|
|
533 return NGX_CONF_OK;
|
|
534 }
|
|
535
|
|
536
|
|
537 static ngx_int_t
|
|
538 ngx_http_limit_zone_init(ngx_conf_t *cf)
|
|
539 {
|
|
540 ngx_http_handler_pt *h;
|
|
541 ngx_http_core_main_conf_t *cmcf;
|
|
542
|
|
543 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
|
|
544
|
|
545 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
|
|
546 if (h == NULL) {
|
|
547 return NGX_ERROR;
|
|
548 }
|
|
549
|
|
550 *h = ngx_http_limit_zone_handler;
|
|
551
|
|
552 return NGX_OK;
|
|
553 }
|