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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544
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36 ngx_uint_t log_level;
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272
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37 } ngx_http_limit_zone_conf_t;
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38
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39
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40 static void ngx_http_limit_zone_cleanup(void *data);
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41
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42 static void *ngx_http_limit_zone_create_conf(ngx_conf_t *cf);
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43 static char *ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent,
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44 void *child);
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45 static char *ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd,
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46 void *conf);
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47 static char *ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd,
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48 void *conf);
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49 static ngx_int_t ngx_http_limit_zone_init(ngx_conf_t *cf);
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50
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51
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544
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52 static ngx_conf_enum_t ngx_http_limit_conn_log_levels[] = {
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53 { ngx_string("info"), NGX_LOG_INFO },
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54 { ngx_string("notice"), NGX_LOG_NOTICE },
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55 { ngx_string("warn"), NGX_LOG_WARN },
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56 { ngx_string("error"), NGX_LOG_ERR },
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57 { ngx_null_string, 0 }
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58 };
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59
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60
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272
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61 static ngx_command_t ngx_http_limit_zone_commands[] = {
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62
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63 { ngx_string("limit_zone"),
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64 NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE3,
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65 ngx_http_limit_zone,
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66 0,
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67 0,
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68 NULL },
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69
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70 { ngx_string("limit_conn"),
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71 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
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72 ngx_http_limit_conn,
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73 NGX_HTTP_LOC_CONF_OFFSET,
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74 0,
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75 NULL },
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76
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544
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77 { ngx_string("limit_conn_log_level"),
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78 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
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79 ngx_conf_set_enum_slot,
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80 NGX_HTTP_LOC_CONF_OFFSET,
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81 offsetof(ngx_http_limit_zone_conf_t, log_level),
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82 &ngx_http_limit_conn_log_levels },
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83
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272
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84 ngx_null_command
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85 };
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86
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87
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88 static ngx_http_module_t ngx_http_limit_zone_module_ctx = {
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89 NULL, /* preconfiguration */
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90 ngx_http_limit_zone_init, /* postconfiguration */
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91
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92 NULL, /* create main configuration */
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93 NULL, /* init main configuration */
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94
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95 NULL, /* create server configuration */
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96 NULL, /* merge server configuration */
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97
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98 ngx_http_limit_zone_create_conf, /* create location configration */
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99 ngx_http_limit_zone_merge_conf /* merge location configration */
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100 };
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101
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102
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103 ngx_module_t ngx_http_limit_zone_module = {
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104 NGX_MODULE_V1,
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105 &ngx_http_limit_zone_module_ctx, /* module context */
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106 ngx_http_limit_zone_commands, /* module directives */
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107 NGX_HTTP_MODULE, /* module type */
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108 NULL, /* init master */
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109 NULL, /* init module */
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110 NULL, /* init process */
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111 NULL, /* init thread */
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112 NULL, /* exit thread */
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113 NULL, /* exit process */
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114 NULL, /* exit master */
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115 NGX_MODULE_V1_PADDING
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116 };
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117
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118
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119 static ngx_int_t
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120 ngx_http_limit_zone_handler(ngx_http_request_t *r)
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121 {
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122 size_t len, n;
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123 uint32_t hash;
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274
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124 ngx_int_t rc;
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272
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125 ngx_slab_pool_t *shpool;
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126 ngx_rbtree_node_t *node, *sentinel;
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127 ngx_pool_cleanup_t *cln;
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128 ngx_http_variable_value_t *vv;
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129 ngx_http_limit_zone_ctx_t *ctx;
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130 ngx_http_limit_zone_node_t *lz;
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131 ngx_http_limit_zone_conf_t *lzcf;
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132 ngx_http_limit_zone_cleanup_t *lzcln;
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133
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134 if (r->main->limit_zone_set) {
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135 return NGX_DECLINED;
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136 }
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137
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138 lzcf = ngx_http_get_module_loc_conf(r, ngx_http_limit_zone_module);
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139
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140 if (lzcf->shm_zone == NULL) {
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141 return NGX_DECLINED;
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142 }
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143
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144 ctx = lzcf->shm_zone->data;
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145
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146 vv = ngx_http_get_indexed_variable(r, ctx->index);
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147
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148 if (vv == NULL || vv->not_found) {
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149 return NGX_DECLINED;
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150 }
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151
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274
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152 len = vv->len;
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153
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154 if (len == 0) {
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155 return NGX_DECLINED;
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156 }
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272
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157
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274
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158 if (len > 255) {
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159 ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
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160 "the value of the \"%V\" variable "
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328
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161 "is more than 255 bytes: \"%v\"",
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274
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162 &ctx->var, vv);
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163 return NGX_DECLINED;
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164 }
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165
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166 r->main->limit_zone_set = 1;
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272
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167
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168 hash = ngx_crc32_short(vv->data, len);
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169
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170 cln = ngx_pool_cleanup_add(r->pool, sizeof(ngx_http_limit_zone_cleanup_t));
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171 if (cln == NULL) {
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172 return NGX_HTTP_INTERNAL_SERVER_ERROR;
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173 }
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174
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175 shpool = (ngx_slab_pool_t *) lzcf->shm_zone->shm.addr;
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176
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177 ngx_shmtx_lock(&shpool->mutex);
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178
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179 node = ctx->rbtree->root;
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180 sentinel = ctx->rbtree->sentinel;
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181
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182 while (node != sentinel) {
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183
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184 if (hash < node->key) {
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185 node = node->left;
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186 continue;
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187 }
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188
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189 if (hash > node->key) {
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190 node = node->right;
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191 continue;
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192 }
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193
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274
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194 /* hash == node->key */
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195
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196 do {
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272
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197 lz = (ngx_http_limit_zone_node_t *) &node->color;
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198
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276
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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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201 if (rc == 0) {
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272
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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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205 }
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206
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207 ngx_shmtx_unlock(&shpool->mutex);
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208
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544
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209 ngx_log_error(lzcf->log_level, r->connection->log, 0,
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435
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210 "limiting connections by zone \"%V\"",
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489
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211 &lzcf->shm_zone->shm.name);
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435
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212
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272
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213 return NGX_HTTP_SERVICE_UNAVAILABLE;
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214 }
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274
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215
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216 node = (rc < 0) ? node->left : node->right;
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217
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218 } while (node != sentinel && hash == node->key);
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219
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220 break;
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272
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221 }
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222
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223 n = offsetof(ngx_rbtree_node_t, color)
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224 + offsetof(ngx_http_limit_zone_node_t, data)
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225 + len;
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226
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227 node = ngx_slab_alloc_locked(shpool, n);
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228 if (node == NULL) {
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229 ngx_shmtx_unlock(&shpool->mutex);
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230 return NGX_HTTP_SERVICE_UNAVAILABLE;
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231 }
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232
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233 lz = (ngx_http_limit_zone_node_t *) &node->color;
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234
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235 node->key = hash;
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236 lz->len = (u_char) len;
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237 lz->conn = 1;
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238 ngx_memcpy(lz->data, vv->data, len);
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239
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240 ngx_rbtree_insert(ctx->rbtree, node);
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241
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242 done:
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243
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244 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
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245 "limit zone: %08XD %d", node->key, lz->conn);
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246
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247 ngx_shmtx_unlock(&shpool->mutex);
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248
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249 cln->handler = ngx_http_limit_zone_cleanup;
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250 lzcln = cln->data;
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251
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252 lzcln->shm_zone = lzcf->shm_zone;
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253 lzcln->node = node;
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254
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255 return NGX_DECLINED;
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256 }
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257
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258
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259 static void
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274
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260 ngx_http_limit_zone_rbtree_insert_value(ngx_rbtree_node_t *temp,
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261 ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel)
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262 {
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356
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263 ngx_rbtree_node_t **p;
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264 ngx_http_limit_zone_node_t *lzn, *lznt;
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274
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265
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266 for ( ;; ) {
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267
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268 if (node->key < temp->key) {
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269
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356
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270 p = &temp->left;
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274
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271
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272 } else if (node->key > temp->key) {
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273
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356
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274 p = &temp->right;
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274
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275
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276 } else { /* node->key == temp->key */
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277
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278 lzn = (ngx_http_limit_zone_node_t *) &node->color;
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279 lznt = (ngx_http_limit_zone_node_t *) &temp->color;
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280
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356
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281 p = (ngx_memn2cmp(lzn->data, lznt->data, lzn->len, lznt->len) < 0)
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282 ? &temp->left : &temp->right;
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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 if (*p == sentinel) {
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286 break;
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287 }
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274
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288
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356
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289 temp = *p;
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274
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290 }
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291
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356
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292 *p = node;
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274
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293 node->parent = temp;
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294 node->left = sentinel;
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295 node->right = sentinel;
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296 ngx_rbt_red(node);
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297 }
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298
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299
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300 static void
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272
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301 ngx_http_limit_zone_cleanup(void *data)
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302 {
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303 ngx_http_limit_zone_cleanup_t *lzcln = data;
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304
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305 ngx_slab_pool_t *shpool;
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306 ngx_rbtree_node_t *node;
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307 ngx_http_limit_zone_ctx_t *ctx;
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308 ngx_http_limit_zone_node_t *lz;
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309
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310 ctx = lzcln->shm_zone->data;
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311 shpool = (ngx_slab_pool_t *) lzcln->shm_zone->shm.addr;
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312 node = lzcln->node;
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313 lz = (ngx_http_limit_zone_node_t *) &node->color;
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314
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315 ngx_shmtx_lock(&shpool->mutex);
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316
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317 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, lzcln->shm_zone->shm.log, 0,
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318 "limit zone cleanup: %08XD %d", node->key, lz->conn);
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319
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320 lz->conn--;
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321
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322 if (lz->conn == 0) {
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323 ngx_rbtree_delete(ctx->rbtree, node);
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324 ngx_slab_free_locked(shpool, node);
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325 }
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326
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327 ngx_shmtx_unlock(&shpool->mutex);
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328 }
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329
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330
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331 static ngx_int_t
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332 ngx_http_limit_zone_init_zone(ngx_shm_zone_t *shm_zone, void *data)
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333 {
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334 ngx_http_limit_zone_ctx_t *octx = data;
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335
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477
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336 size_t len;
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272
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337 ngx_slab_pool_t *shpool;
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338 ngx_rbtree_node_t *sentinel;
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339 ngx_http_limit_zone_ctx_t *ctx;
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340
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341 ctx = shm_zone->data;
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342
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343 if (octx) {
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344 if (ngx_strcmp(ctx->var.data, octx->var.data) != 0) {
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345 ngx_log_error(NGX_LOG_EMERG, shm_zone->shm.log, 0,
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274
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346 "limit_zone \"%V\" uses the \"%V\" variable "
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272
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347 "while previously it used the \"%V\" variable",
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489
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348 &shm_zone->shm.name, &ctx->var, &octx->var);
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272
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349 return NGX_ERROR;
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350 }
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351
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352 ctx->rbtree = octx->rbtree;
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353
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354 return NGX_OK;
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355 }
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356
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357 shpool = (ngx_slab_pool_t *) shm_zone->shm.addr;
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358
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489
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359 if (shm_zone->shm.exists) {
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360 ctx->rbtree = shpool->data;
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361
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362 return NGX_OK;
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363 }
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364
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272
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365 ctx->rbtree = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_t));
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366 if (ctx->rbtree == NULL) {
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367 return NGX_ERROR;
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368 }
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369
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489
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370 shpool->data = ctx->rbtree;
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371
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272
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372 sentinel = ngx_slab_alloc(shpool, sizeof(ngx_rbtree_node_t));
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373 if (sentinel == NULL) {
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374 return NGX_ERROR;
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375 }
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376
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356
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377 ngx_rbtree_init(ctx->rbtree, sentinel,
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378 ngx_http_limit_zone_rbtree_insert_value);
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272
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379
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489
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380 len = sizeof(" in limit_zone \"\"") + shm_zone->shm.name.len;
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477
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381
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382 shpool->log_ctx = ngx_slab_alloc(shpool, len);
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383 if (shpool->log_ctx == NULL) {
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384 return NGX_ERROR;
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385 }
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386
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489
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387 ngx_sprintf(shpool->log_ctx, " in limit_zone \"%V\"%Z",
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388 &shm_zone->shm.name);
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477
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389
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272
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390 return NGX_OK;
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391 }
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392
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393
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394 static void *
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395 ngx_http_limit_zone_create_conf(ngx_conf_t *cf)
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396 {
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397 ngx_http_limit_zone_conf_t *conf;
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398
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399 conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_conf_t));
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400 if (conf == NULL) {
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505
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401 return NULL;
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272
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402 }
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403
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404 /*
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405 * set by ngx_pcalloc():
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406 *
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407 * conf->shm_zone = NULL;
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408 * conf->conn = 0;
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409 */
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410
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544
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411 conf->log_level = NGX_CONF_UNSET_UINT;
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412
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272
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413 return conf;
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414 }
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415
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416
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417 static char *
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418 ngx_http_limit_zone_merge_conf(ngx_conf_t *cf, void *parent, void *child)
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419 {
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420 ngx_http_limit_zone_conf_t *prev = parent;
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421 ngx_http_limit_zone_conf_t *conf = child;
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422
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423 if (conf->shm_zone == NULL) {
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424 *conf = *prev;
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425 }
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426
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544
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427 ngx_conf_merge_uint_value(conf->log_level, prev->log_level, NGX_LOG_ERR);
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428
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272
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429 return NGX_CONF_OK;
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430 }
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431
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432
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433 static char *
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434 ngx_http_limit_zone(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
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435 {
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436 ssize_t n;
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437 ngx_str_t *value;
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438 ngx_shm_zone_t *shm_zone;
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439 ngx_http_limit_zone_ctx_t *ctx;
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440
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441 value = cf->args->elts;
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442
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443 if (value[2].data[0] != '$') {
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444 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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445 "invalid variable name \"%V\"", &value[2]);
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446 return NGX_CONF_ERROR;
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447 }
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448
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449 value[2].len--;
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450 value[2].data++;
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451
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452 ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_limit_zone_ctx_t));
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453 if (ctx == NULL) {
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454 return NGX_CONF_ERROR;
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455 }
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456
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457 ctx->index = ngx_http_get_variable_index(cf, &value[2]);
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458 if (ctx->index == NGX_ERROR) {
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459 return NGX_CONF_ERROR;
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460 }
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461
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462 ctx->var = value[2];
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463
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464 n = ngx_parse_size(&value[3]);
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465
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466 if (n == NGX_ERROR) {
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467 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
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468 "invalid size of limit_zone \"%V\"", &value[3]);
|
|
469 return NGX_CONF_ERROR;
|
|
470 }
|
|
471
|
|
472 if (n < (ngx_int_t) (8 * ngx_pagesize)) {
|
|
473 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
474 "limit_zone \"%V\" is too small", &value[1]);
|
|
475 return NGX_CONF_ERROR;
|
|
476 }
|
|
477
|
|
478
|
|
479 shm_zone = ngx_shared_memory_add(cf, &value[1], n,
|
|
480 &ngx_http_limit_zone_module);
|
|
481 if (shm_zone == NULL) {
|
|
482 return NGX_CONF_ERROR;
|
|
483 }
|
|
484
|
|
485 if (shm_zone->data) {
|
|
486 ctx = shm_zone->data;
|
|
487
|
|
488 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
489 "limit_zone \"%V\" is already bound to variable \"%V\"",
|
|
490 &value[1], &ctx->var);
|
|
491 return NGX_CONF_ERROR;
|
|
492 }
|
|
493
|
|
494 shm_zone->init = ngx_http_limit_zone_init_zone;
|
|
495 shm_zone->data = ctx;
|
|
496
|
|
497 return NGX_CONF_OK;
|
|
498 }
|
|
499
|
|
500
|
|
501 static char *
|
|
502 ngx_http_limit_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
|
|
503 {
|
|
504 ngx_http_limit_zone_conf_t *lzcf = conf;
|
|
505
|
|
506 ngx_int_t n;
|
|
507 ngx_str_t *value;
|
|
508
|
435
|
509 if (lzcf->shm_zone) {
|
|
510 return "is duplicate";
|
|
511 }
|
|
512
|
272
|
513 value = cf->args->elts;
|
|
514
|
|
515 lzcf->shm_zone = ngx_shared_memory_add(cf, &value[1], 0,
|
|
516 &ngx_http_limit_zone_module);
|
|
517 if (lzcf->shm_zone == NULL) {
|
|
518 return NGX_CONF_ERROR;
|
|
519 }
|
|
520
|
|
521 n = ngx_atoi(value[2].data, value[2].len);
|
|
522 if (n <= 0) {
|
|
523 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
524 "invalid number of connections \"%V\"", &value[2]);
|
|
525 return NGX_CONF_ERROR;
|
|
526 }
|
|
527
|
274
|
528 if (n > 65535) {
|
|
529 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
|
|
530 "connection limit must be less 65536");
|
|
531 return NGX_CONF_ERROR;
|
|
532 }
|
|
533
|
272
|
534 lzcf->conn = n;
|
|
535
|
|
536 return NGX_CONF_OK;
|
|
537 }
|
|
538
|
|
539
|
|
540 static ngx_int_t
|
|
541 ngx_http_limit_zone_init(ngx_conf_t *cf)
|
|
542 {
|
|
543 ngx_http_handler_pt *h;
|
|
544 ngx_http_core_main_conf_t *cmcf;
|
|
545
|
|
546 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
|
|
547
|
|
548 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers);
|
|
549 if (h == NULL) {
|
|
550 return NGX_ERROR;
|
|
551 }
|
|
552
|
|
553 *h = ngx_http_limit_zone_handler;
|
|
554
|
|
555 return NGX_OK;
|
|
556 }
|