view src/http/modules/ngx_http_proxy_module.c @ 4009:3183165283cc

Fixing proxy_set_body and proxy_pass_request_body with SSL. Flush flag wasn't set in constructed buffer and this prevented any data from being actually sent to upstream due to SSL buffering. Make sure we always set flush in the last buffer we are going to sent. See here for report: http://nginx.org/pipermail/nginx-ru/2011-June/041552.html
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 18 Aug 2011 16:34:24 +0000
parents 2527cdb8d31f
children e5df04b05e75
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct ngx_http_proxy_redirect_s  ngx_http_proxy_redirect_t;

typedef ngx_int_t (*ngx_http_proxy_redirect_pt)(ngx_http_request_t *r,
    ngx_table_elt_t *h, size_t prefix, ngx_http_proxy_redirect_t *pr);

struct ngx_http_proxy_redirect_s {
    ngx_http_proxy_redirect_pt     handler;
    ngx_str_t                      redirect;

    union {
        ngx_str_t                  text;

        struct {
            void                  *lengths;
            void                  *values;
        } vars;

        void                      *regex;
    } replacement;
};


typedef struct {
    ngx_str_t                      key_start;
    ngx_str_t                      schema;
    ngx_str_t                      host_header;
    ngx_str_t                      port;
    ngx_str_t                      uri;
} ngx_http_proxy_vars_t;


typedef struct {
    ngx_http_upstream_conf_t       upstream;

    ngx_array_t                   *flushes;
    ngx_array_t                   *body_set_len;
    ngx_array_t                   *body_set;
    ngx_array_t                   *headers_set_len;
    ngx_array_t                   *headers_set;
    ngx_hash_t                     headers_set_hash;

    ngx_array_t                   *headers_source;

    ngx_array_t                   *proxy_lengths;
    ngx_array_t                   *proxy_values;

    ngx_array_t                   *redirects;

    ngx_str_t                      body_source;

    ngx_str_t                      method;
    ngx_str_t                      location;
    ngx_str_t                      url;

#if (NGX_HTTP_CACHE)
    ngx_http_complex_value_t       cache_key;
#endif

    ngx_http_proxy_vars_t          vars;

    ngx_flag_t                     redirect;

    ngx_uint_t                     headers_hash_max_size;
    ngx_uint_t                     headers_hash_bucket_size;
} ngx_http_proxy_loc_conf_t;


typedef struct {
    ngx_http_status_t              status;
    ngx_http_proxy_vars_t          vars;
    size_t                         internal_body_length;
} ngx_http_proxy_ctx_t;


static ngx_int_t ngx_http_proxy_eval(ngx_http_request_t *r,
    ngx_http_proxy_ctx_t *ctx, ngx_http_proxy_loc_conf_t *plcf);
#if (NGX_HTTP_CACHE)
static ngx_int_t ngx_http_proxy_create_key(ngx_http_request_t *r);
#endif
static ngx_int_t ngx_http_proxy_create_request(ngx_http_request_t *r);
static ngx_int_t ngx_http_proxy_reinit_request(ngx_http_request_t *r);
static ngx_int_t ngx_http_proxy_process_status_line(ngx_http_request_t *r);
static ngx_int_t ngx_http_proxy_process_header(ngx_http_request_t *r);
static void ngx_http_proxy_abort_request(ngx_http_request_t *r);
static void ngx_http_proxy_finalize_request(ngx_http_request_t *r,
    ngx_int_t rc);

static ngx_int_t ngx_http_proxy_host_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_proxy_port_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t
    ngx_http_proxy_add_x_forwarded_for_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t
    ngx_http_proxy_internal_body_length_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_proxy_rewrite_redirect(ngx_http_request_t *r,
    ngx_table_elt_t *h, size_t prefix);

static ngx_int_t ngx_http_proxy_add_variables(ngx_conf_t *cf);
static void *ngx_http_proxy_create_loc_conf(ngx_conf_t *cf);
static char *ngx_http_proxy_merge_loc_conf(ngx_conf_t *cf,
    void *parent, void *child);
static ngx_int_t ngx_http_proxy_merge_headers(ngx_conf_t *cf,
    ngx_http_proxy_loc_conf_t *conf, ngx_http_proxy_loc_conf_t *prev);

static char *ngx_http_proxy_pass(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_proxy_redirect(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_proxy_store(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
#if (NGX_HTTP_CACHE)
static char *ngx_http_proxy_cache(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_proxy_cache_key(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
#endif

static char *ngx_http_proxy_lowat_check(ngx_conf_t *cf, void *post, void *data);

#if (NGX_HTTP_SSL)
static ngx_int_t ngx_http_proxy_set_ssl(ngx_conf_t *cf,
    ngx_http_proxy_loc_conf_t *plcf);
#endif
static void ngx_http_proxy_set_vars(ngx_url_t *u, ngx_http_proxy_vars_t *v);


static ngx_conf_post_t  ngx_http_proxy_lowat_post =
    { ngx_http_proxy_lowat_check };


static ngx_conf_bitmask_t  ngx_http_proxy_next_upstream_masks[] = {
    { ngx_string("error"), NGX_HTTP_UPSTREAM_FT_ERROR },
    { ngx_string("timeout"), NGX_HTTP_UPSTREAM_FT_TIMEOUT },
    { ngx_string("invalid_header"), NGX_HTTP_UPSTREAM_FT_INVALID_HEADER },
    { ngx_string("http_500"), NGX_HTTP_UPSTREAM_FT_HTTP_500 },
    { ngx_string("http_502"), NGX_HTTP_UPSTREAM_FT_HTTP_502 },
    { ngx_string("http_503"), NGX_HTTP_UPSTREAM_FT_HTTP_503 },
    { ngx_string("http_504"), NGX_HTTP_UPSTREAM_FT_HTTP_504 },
    { ngx_string("http_404"), NGX_HTTP_UPSTREAM_FT_HTTP_404 },
    { ngx_string("updating"), NGX_HTTP_UPSTREAM_FT_UPDATING },
    { ngx_string("off"), NGX_HTTP_UPSTREAM_FT_OFF },
    { ngx_null_string, 0 }
};


ngx_module_t  ngx_http_proxy_module;


static ngx_command_t  ngx_http_proxy_commands[] = {

    { ngx_string("proxy_pass"),
      NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF|NGX_HTTP_LMT_CONF|NGX_CONF_TAKE1,
      ngx_http_proxy_pass,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("proxy_redirect"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
      ngx_http_proxy_redirect,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("proxy_store"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_proxy_store,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("proxy_store_access"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE123,
      ngx_conf_set_access_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.store_access),
      NULL },

    { ngx_string("proxy_buffering"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.buffering),
      NULL },

    { ngx_string("proxy_ignore_client_abort"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.ignore_client_abort),
      NULL },

    { ngx_string("proxy_bind"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_upstream_bind_set_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.local),
      NULL },

    { ngx_string("proxy_connect_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.connect_timeout),
      NULL },

    { ngx_string("proxy_send_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.send_timeout),
      NULL },

    { ngx_string("proxy_send_lowat"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.send_lowat),
      &ngx_http_proxy_lowat_post },

    { ngx_string("proxy_intercept_errors"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.intercept_errors),
      NULL },

    { ngx_string("proxy_set_header"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
      ngx_conf_set_keyval_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, headers_source),
      NULL },

    { ngx_string("proxy_headers_hash_max_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, headers_hash_max_size),
      NULL },

    { ngx_string("proxy_headers_hash_bucket_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, headers_hash_bucket_size),
      NULL },

    { ngx_string("proxy_set_body"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, body_source),
      NULL },

    { ngx_string("proxy_method"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, method),
      NULL },

    { ngx_string("proxy_pass_request_headers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.pass_request_headers),
      NULL },

    { ngx_string("proxy_pass_request_body"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.pass_request_body),
      NULL },

    { ngx_string("proxy_buffer_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.buffer_size),
      NULL },

    { ngx_string("proxy_read_timeout"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.read_timeout),
      NULL },

    { ngx_string("proxy_buffers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
      ngx_conf_set_bufs_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.bufs),
      NULL },

    { ngx_string("proxy_busy_buffers_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.busy_buffers_size_conf),
      NULL },

#if (NGX_HTTP_CACHE)

    { ngx_string("proxy_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_proxy_cache,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("proxy_cache_key"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_http_proxy_cache_key,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },

    { ngx_string("proxy_cache_path"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_2MORE,
      ngx_http_file_cache_set_slot,
      0,
      0,
      &ngx_http_proxy_module },

    { ngx_string("proxy_cache_bypass"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_set_predicate_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_bypass),
      NULL },

    { ngx_string("proxy_no_cache"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_set_predicate_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.no_cache),
      NULL },

    { ngx_string("proxy_cache_valid"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_http_file_cache_valid_set_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_valid),
      NULL },

    { ngx_string("proxy_cache_min_uses"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_num_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_min_uses),
      NULL },

    { ngx_string("proxy_cache_use_stale"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_use_stale),
      &ngx_http_proxy_next_upstream_masks },

    { ngx_string("proxy_cache_methods"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.cache_methods),
      &ngx_http_upstream_cache_method_mask },

#endif

    { ngx_string("proxy_temp_path"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1234,
      ngx_conf_set_path_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.temp_path),
      NULL },

    { ngx_string("proxy_max_temp_file_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.max_temp_file_size_conf),
      NULL },

    { ngx_string("proxy_temp_file_write_size"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_size_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.temp_file_write_size_conf),
      NULL },

    { ngx_string("proxy_next_upstream"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.next_upstream),
      &ngx_http_proxy_next_upstream_masks },

    { ngx_string("proxy_pass_header"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.pass_headers),
      NULL },

    { ngx_string("proxy_hide_header"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_array_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.hide_headers),
      NULL },

    { ngx_string("proxy_ignore_headers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
      ngx_conf_set_bitmask_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.ignore_headers),
      &ngx_http_upstream_ignore_headers_masks },

#if (NGX_HTTP_SSL)

    { ngx_string("proxy_ssl_session_reuse"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_proxy_loc_conf_t, upstream.ssl_session_reuse),
      NULL },

#endif

      ngx_null_command
};


static ngx_http_module_t  ngx_http_proxy_module_ctx = {
    ngx_http_proxy_add_variables,          /* preconfiguration */
    NULL,                                  /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_proxy_create_loc_conf,        /* create location configration */
    ngx_http_proxy_merge_loc_conf          /* merge location configration */
};


ngx_module_t  ngx_http_proxy_module = {
    NGX_MODULE_V1,
    &ngx_http_proxy_module_ctx,            /* module context */
    ngx_http_proxy_commands,               /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static char  ngx_http_proxy_version[] = " HTTP/1.0" CRLF;


static ngx_keyval_t  ngx_http_proxy_headers[] = {
    { ngx_string("Host"), ngx_string("$proxy_host") },
    { ngx_string("Connection"), ngx_string("close") },
    { ngx_string("Keep-Alive"), ngx_string("") },
    { ngx_string("Expect"), ngx_string("") },
    { ngx_null_string, ngx_null_string }
};


static ngx_str_t  ngx_http_proxy_hide_headers[] = {
    ngx_string("Date"),
    ngx_string("Server"),
    ngx_string("X-Pad"),
    ngx_string("X-Accel-Expires"),
    ngx_string("X-Accel-Redirect"),
    ngx_string("X-Accel-Limit-Rate"),
    ngx_string("X-Accel-Buffering"),
    ngx_string("X-Accel-Charset"),
    ngx_null_string
};


#if (NGX_HTTP_CACHE)

static ngx_keyval_t  ngx_http_proxy_cache_headers[] = {
    { ngx_string("Host"), ngx_string("$proxy_host") },
    { ngx_string("Connection"), ngx_string("close") },
    { ngx_string("Keep-Alive"), ngx_string("") },
    { ngx_string("Expect"), ngx_string("") },
    { ngx_string("If-Modified-Since"), ngx_string("") },
    { ngx_string("If-Unmodified-Since"), ngx_string("") },
    { ngx_string("If-None-Match"), ngx_string("") },
    { ngx_string("If-Match"), ngx_string("") },
    { ngx_string("Range"), ngx_string("") },
    { ngx_string("If-Range"), ngx_string("") },
    { ngx_null_string, ngx_null_string }
};

#endif


static ngx_http_variable_t  ngx_http_proxy_vars[] = {

    { ngx_string("proxy_host"), NULL, ngx_http_proxy_host_variable, 0,
      NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0 },

    { ngx_string("proxy_port"), NULL, ngx_http_proxy_port_variable, 0,
      NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0 },

    { ngx_string("proxy_add_x_forwarded_for"), NULL,
      ngx_http_proxy_add_x_forwarded_for_variable, 0, NGX_HTTP_VAR_NOHASH, 0 },

#if 0
    { ngx_string("proxy_add_via"), NULL, NULL, 0, NGX_HTTP_VAR_NOHASH, 0 },
#endif

    { ngx_string("proxy_internal_body_length"), NULL,
      ngx_http_proxy_internal_body_length_variable, 0, NGX_HTTP_VAR_NOHASH, 0 },

    { ngx_null_string, NULL, NULL, 0, 0, 0 }
};


static ngx_path_init_t  ngx_http_proxy_temp_path = {
    ngx_string(NGX_HTTP_PROXY_TEMP_PATH), { 1, 2, 0 }
};


static ngx_int_t
ngx_http_proxy_handler(ngx_http_request_t *r)
{
    ngx_int_t                   rc;
    ngx_http_upstream_t        *u;
    ngx_http_proxy_ctx_t       *ctx;
    ngx_http_proxy_loc_conf_t  *plcf;

    if (ngx_http_upstream_create(r) != NGX_OK) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_proxy_ctx_t));
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    ngx_http_set_ctx(r, ctx, ngx_http_proxy_module);

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    u = r->upstream;

    if (plcf->proxy_lengths == NULL) {
        ctx->vars = plcf->vars;
        u->schema = plcf->vars.schema;
#if (NGX_HTTP_SSL)
        u->ssl = (plcf->upstream.ssl != NULL);
#endif

    } else {
        if (ngx_http_proxy_eval(r, ctx, plcf) != NGX_OK) {
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    u->output.tag = (ngx_buf_tag_t) &ngx_http_proxy_module;

    u->conf = &plcf->upstream;

#if (NGX_HTTP_CACHE)
    u->create_key = ngx_http_proxy_create_key;
#endif
    u->create_request = ngx_http_proxy_create_request;
    u->reinit_request = ngx_http_proxy_reinit_request;
    u->process_header = ngx_http_proxy_process_status_line;
    u->abort_request = ngx_http_proxy_abort_request;
    u->finalize_request = ngx_http_proxy_finalize_request;
    r->state = 0;

    if (plcf->redirects) {
        u->rewrite_redirect = ngx_http_proxy_rewrite_redirect;
    }

    u->buffering = plcf->upstream.buffering;

    u->pipe = ngx_pcalloc(r->pool, sizeof(ngx_event_pipe_t));
    if (u->pipe == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    u->pipe->input_filter = ngx_event_pipe_copy_input_filter;

    u->accel = 1;

    rc = ngx_http_read_client_request_body(r, ngx_http_upstream_init);

    if (rc >= NGX_HTTP_SPECIAL_RESPONSE) {
        return rc;
    }

    return NGX_DONE;
}


static ngx_int_t
ngx_http_proxy_eval(ngx_http_request_t *r, ngx_http_proxy_ctx_t *ctx,
    ngx_http_proxy_loc_conf_t *plcf)
{
    u_char               *p;
    size_t                add;
    u_short               port;
    ngx_str_t             proxy;
    ngx_url_t             url;
    ngx_http_upstream_t  *u;

    if (ngx_http_script_run(r, &proxy, plcf->proxy_lengths->elts, 0,
                            plcf->proxy_values->elts)
        == NULL)
    {
        return NGX_ERROR;
    }

    if (proxy.len > 7
        && ngx_strncasecmp(proxy.data, (u_char *) "http://", 7) == 0)
    {
        add = 7;
        port = 80;

#if (NGX_HTTP_SSL)

    } else if (proxy.len > 8
               && ngx_strncasecmp(proxy.data, (u_char *) "https://", 8) == 0)
    {
        add = 8;
        port = 443;
        r->upstream->ssl = 1;

#endif

    } else {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "invalid URL prefix in \"%V\"", &proxy);
        return NGX_ERROR;
    }

    u = r->upstream;

    u->schema.len = add;
    u->schema.data = proxy.data;

    ngx_memzero(&url, sizeof(ngx_url_t));

    url.url.len = proxy.len - add;
    url.url.data = proxy.data + add;
    url.default_port = port;
    url.uri_part = 1;
    url.no_resolve = 1;

    if (ngx_parse_url(r->pool, &url) != NGX_OK) {
        if (url.err) {
            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                          "%s in upstream \"%V\"", url.err, &url.url);
        }

        return NGX_ERROR;
    }

    if (url.uri.len) {
        if (url.uri.data[0] == '?') {
            p = ngx_pnalloc(r->pool, url.uri.len + 1);
            if (p == NULL) {
                return NGX_ERROR;
            }

            *p++ = '/';
            ngx_memcpy(p, url.uri.data, url.uri.len);

            url.uri.len++;
            url.uri.data = p - 1;
        }

    } else {
        url.uri = r->unparsed_uri;
    }

    ctx->vars.key_start = u->schema;

    ngx_http_proxy_set_vars(&url, &ctx->vars);

    u->resolved = ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_resolved_t));
    if (u->resolved == NULL) {
        return NGX_ERROR;
    }

    if (url.addrs && url.addrs[0].sockaddr) {
        u->resolved->sockaddr = url.addrs[0].sockaddr;
        u->resolved->socklen = url.addrs[0].socklen;
        u->resolved->naddrs = 1;
        u->resolved->host = url.addrs[0].name;

    } else {
        u->resolved->host = url.host;
        u->resolved->port = (in_port_t) (url.no_port ? port : url.port);
        u->resolved->no_port = url.no_port;
    }

    return NGX_OK;
}


#if (NGX_HTTP_CACHE)

static ngx_int_t
ngx_http_proxy_create_key(ngx_http_request_t *r)
{
    size_t                      len, loc_len;
    u_char                     *p;
    uintptr_t                   escape;
    ngx_str_t                  *key;
    ngx_http_upstream_t        *u;
    ngx_http_proxy_ctx_t       *ctx;
    ngx_http_proxy_loc_conf_t  *plcf;

    u = r->upstream;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    key = ngx_array_push(&r->cache->keys);
    if (key == NULL) {
        return NGX_ERROR;
    }

    if (plcf->cache_key.value.len) {

        if (ngx_http_complex_value(r, &plcf->cache_key, key) != NGX_OK) {
            return NGX_ERROR;
        }

        return NGX_OK;
    }

    *key = ctx->vars.key_start;

    key = ngx_array_push(&r->cache->keys);
    if (key == NULL) {
        return NGX_ERROR;
    }

    if (plcf->proxy_lengths) {

        *key = ctx->vars.uri;
        u->uri = ctx->vars.uri;

        return NGX_OK;

    } else if (ctx->vars.uri.len == 0 && r->valid_unparsed_uri && r == r->main)
    {
        *key = r->unparsed_uri;
        u->uri = r->unparsed_uri;

        return NGX_OK;
    }

    loc_len = (r->valid_location && ctx->vars.uri.len) ? plcf->location.len : 0;

    if (r->quoted_uri || r->internal) {
        escape = 2 * ngx_escape_uri(NULL, r->uri.data + loc_len,
                                    r->uri.len - loc_len, NGX_ESCAPE_URI);
    } else {
        escape = 0;
    }

    len = ctx->vars.uri.len + r->uri.len - loc_len + escape
          + sizeof("?") - 1 + r->args.len;

    p = ngx_pnalloc(r->pool, len);
    if (p == NULL) {
        return NGX_ERROR;
    }

    key->data = p;

    if (r->valid_location) {
        p = ngx_copy(p, ctx->vars.uri.data, ctx->vars.uri.len);
    }

    if (escape) {
        ngx_escape_uri(p, r->uri.data + loc_len,
                       r->uri.len - loc_len, NGX_ESCAPE_URI);
        p += r->uri.len - loc_len + escape;

    } else {
        p = ngx_copy(p, r->uri.data + loc_len, r->uri.len - loc_len);
    }

    if (r->args.len > 0) {
        *p++ = '?';
        p = ngx_copy(p, r->args.data, r->args.len);
    }

    key->len = p - key->data;
    u->uri = *key;

    return NGX_OK;
}

#endif


static ngx_int_t
ngx_http_proxy_create_request(ngx_http_request_t *r)
{
    size_t                        len, uri_len, loc_len, body_len;
    uintptr_t                     escape;
    ngx_buf_t                    *b;
    ngx_str_t                     method;
    ngx_uint_t                    i, unparsed_uri;
    ngx_chain_t                  *cl, *body;
    ngx_list_part_t              *part;
    ngx_table_elt_t              *header;
    ngx_http_upstream_t          *u;
    ngx_http_proxy_ctx_t         *ctx;
    ngx_http_script_code_pt       code;
    ngx_http_script_engine_t      e, le;
    ngx_http_proxy_loc_conf_t    *plcf;
    ngx_http_script_len_code_pt   lcode;

    u = r->upstream;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    if (u->method.len) {
        /* HEAD was changed to GET to cache response */
        method = u->method;
        method.len++;

    } else if (plcf->method.len) {
        method = plcf->method;

    } else {
        method = r->method_name;
        method.len++;
    }

    len = method.len + sizeof(ngx_http_proxy_version) - 1 + sizeof(CRLF) - 1;

    escape = 0;
    loc_len = 0;
    unparsed_uri = 0;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (plcf->proxy_lengths) {
        uri_len = ctx->vars.uri.len;

    } else if (ctx->vars.uri.len == 0 && r->valid_unparsed_uri && r == r->main)
    {
        unparsed_uri = 1;
        uri_len = r->unparsed_uri.len;

    } else {
        loc_len = (r->valid_location && ctx->vars.uri.len) ?
                      plcf->location.len : 0;

        if (r->quoted_uri || r->space_in_uri || r->internal) {
            escape = 2 * ngx_escape_uri(NULL, r->uri.data + loc_len,
                                        r->uri.len - loc_len, NGX_ESCAPE_URI);
        }

        uri_len = ctx->vars.uri.len + r->uri.len - loc_len + escape
                  + sizeof("?") - 1 + r->args.len;
    }

    if (uri_len == 0) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "zero length URI to proxy");
        return NGX_ERROR;
    }

    len += uri_len;

    ngx_http_script_flush_no_cacheable_variables(r, plcf->flushes);

    if (plcf->body_set_len) {
        le.ip = plcf->body_set_len->elts;
        le.request = r;
        le.flushed = 1;
        body_len = 0;

        while (*(uintptr_t *) le.ip) {
            lcode = *(ngx_http_script_len_code_pt *) le.ip;
            body_len += lcode(&le);
        }

        ctx->internal_body_length = body_len;
        len += body_len;
    }

    le.ip = plcf->headers_set_len->elts;
    le.request = r;
    le.flushed = 1;

    while (*(uintptr_t *) le.ip) {
        while (*(uintptr_t *) le.ip) {
            lcode = *(ngx_http_script_len_code_pt *) le.ip;
            len += lcode(&le);
        }
        le.ip += sizeof(uintptr_t);
    }


    if (plcf->upstream.pass_request_headers) {
        part = &r->headers_in.headers.part;
        header = part->elts;

        for (i = 0; /* void */; i++) {

            if (i >= part->nelts) {
                if (part->next == NULL) {
                    break;
                }

                part = part->next;
                header = part->elts;
                i = 0;
            }

            if (ngx_hash_find(&plcf->headers_set_hash, header[i].hash,
                              header[i].lowcase_key, header[i].key.len))
            {
                continue;
            }

            len += header[i].key.len + sizeof(": ") - 1
                + header[i].value.len + sizeof(CRLF) - 1;
        }
    }


    b = ngx_create_temp_buf(r->pool, len);
    if (b == NULL) {
        return NGX_ERROR;
    }

    cl = ngx_alloc_chain_link(r->pool);
    if (cl == NULL) {
        return NGX_ERROR;
    }

    cl->buf = b;


    /* the request line */

    b->last = ngx_copy(b->last, method.data, method.len);

    u->uri.data = b->last;

    if (plcf->proxy_lengths) {
        b->last = ngx_copy(b->last, ctx->vars.uri.data, ctx->vars.uri.len);

    } else if (unparsed_uri) {
        b->last = ngx_copy(b->last, r->unparsed_uri.data, r->unparsed_uri.len);

    } else {
        if (r->valid_location) {
            b->last = ngx_copy(b->last, ctx->vars.uri.data, ctx->vars.uri.len);
        }

        if (escape) {
            ngx_escape_uri(b->last, r->uri.data + loc_len,
                           r->uri.len - loc_len, NGX_ESCAPE_URI);
            b->last += r->uri.len - loc_len + escape;

        } else {
            b->last = ngx_copy(b->last, r->uri.data + loc_len,
                               r->uri.len - loc_len);
        }

        if (r->args.len > 0) {
            *b->last++ = '?';
            b->last = ngx_copy(b->last, r->args.data, r->args.len);
        }
    }

    u->uri.len = b->last - u->uri.data;

    b->last = ngx_cpymem(b->last, ngx_http_proxy_version,
                         sizeof(ngx_http_proxy_version) - 1);

    ngx_memzero(&e, sizeof(ngx_http_script_engine_t));

    e.ip = plcf->headers_set->elts;
    e.pos = b->last;
    e.request = r;
    e.flushed = 1;

    le.ip = plcf->headers_set_len->elts;

    while (*(uintptr_t *) le.ip) {
        lcode = *(ngx_http_script_len_code_pt *) le.ip;

        /* skip the header line name length */
        (void) lcode(&le);

        if (*(ngx_http_script_len_code_pt *) le.ip) {

            for (len = 0; *(uintptr_t *) le.ip; len += lcode(&le)) {
                lcode = *(ngx_http_script_len_code_pt *) le.ip;
            }

            e.skip = (len == sizeof(CRLF) - 1) ? 1 : 0;

        } else {
            e.skip = 0;
        }

        le.ip += sizeof(uintptr_t);

        while (*(uintptr_t *) e.ip) {
            code = *(ngx_http_script_code_pt *) e.ip;
            code((ngx_http_script_engine_t *) &e);
        }
        e.ip += sizeof(uintptr_t);
    }

    b->last = e.pos;


    if (plcf->upstream.pass_request_headers) {
        part = &r->headers_in.headers.part;
        header = part->elts;

        for (i = 0; /* void */; i++) {

            if (i >= part->nelts) {
                if (part->next == NULL) {
                    break;
                }

                part = part->next;
                header = part->elts;
                i = 0;
            }

            if (ngx_hash_find(&plcf->headers_set_hash, header[i].hash,
                              header[i].lowcase_key, header[i].key.len))
            {
                continue;
            }

            b->last = ngx_copy(b->last, header[i].key.data, header[i].key.len);

            *b->last++ = ':'; *b->last++ = ' ';

            b->last = ngx_copy(b->last, header[i].value.data,
                               header[i].value.len);

            *b->last++ = CR; *b->last++ = LF;

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http proxy header: \"%V: %V\"",
                           &header[i].key, &header[i].value);
        }
    }


    /* add "\r\n" at the header end */
    *b->last++ = CR; *b->last++ = LF;

    if (plcf->body_set) {
        e.ip = plcf->body_set->elts;
        e.pos = b->last;

        while (*(uintptr_t *) e.ip) {
            code = *(ngx_http_script_code_pt *) e.ip;
            code((ngx_http_script_engine_t *) &e);
        }

        b->last = e.pos;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http proxy header:\n\"%*s\"",
                   (size_t) (b->last - b->pos), b->pos);

    if (plcf->body_set == NULL && plcf->upstream.pass_request_body) {

        body = u->request_bufs;
        u->request_bufs = cl;

        while (body) {
            b = ngx_alloc_buf(r->pool);
            if (b == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(b, body->buf, sizeof(ngx_buf_t));

            cl->next = ngx_alloc_chain_link(r->pool);
            if (cl->next == NULL) {
                return NGX_ERROR;
            }

            cl = cl->next;
            cl->buf = b;

            body = body->next;
        }

    } else {
        u->request_bufs = cl;
    }

    b->flush = 1;
    cl->next = NULL;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_reinit_request(ngx_http_request_t *r)
{
    ngx_http_proxy_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (ctx == NULL) {
        return NGX_OK;
    }

    ctx->status.code = 0;
    ctx->status.count = 0;
    ctx->status.start = NULL;
    ctx->status.end = NULL;

    r->upstream->process_header = ngx_http_proxy_process_status_line;
    r->state = 0;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_process_status_line(ngx_http_request_t *r)
{
    size_t                 len;
    ngx_int_t              rc;
    ngx_http_upstream_t   *u;
    ngx_http_proxy_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (ctx == NULL) {
        return NGX_ERROR;
    }

    u = r->upstream;

    rc = ngx_http_parse_status_line(r, &u->buffer, &ctx->status);

    if (rc == NGX_AGAIN) {
        return rc;
    }

    if (rc == NGX_ERROR) {

#if (NGX_HTTP_CACHE)

        if (r->cache) {
            r->http_version = NGX_HTTP_VERSION_9;
            return NGX_OK;
        }

#endif

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent no valid HTTP/1.0 header");

#if 0
        if (u->accel) {
            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
        }
#endif

        r->http_version = NGX_HTTP_VERSION_9;
        u->state->status = NGX_HTTP_OK;

        return NGX_OK;
    }

    if (u->state) {
        u->state->status = ctx->status.code;
    }

    u->headers_in.status_n = ctx->status.code;

    len = ctx->status.end - ctx->status.start;
    u->headers_in.status_line.len = len;

    u->headers_in.status_line.data = ngx_pnalloc(r->pool, len);
    if (u->headers_in.status_line.data == NULL) {
        return NGX_ERROR;
    }

    ngx_memcpy(u->headers_in.status_line.data, ctx->status.start, len);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http proxy status %ui \"%V\"",
                   u->headers_in.status_n, &u->headers_in.status_line);

    u->process_header = ngx_http_proxy_process_header;

    return ngx_http_proxy_process_header(r);
}


static ngx_int_t
ngx_http_proxy_process_header(ngx_http_request_t *r)
{
    ngx_int_t                       rc;
    ngx_table_elt_t                *h;
    ngx_http_upstream_header_t     *hh;
    ngx_http_upstream_main_conf_t  *umcf;

    umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);

    for ( ;; ) {

        rc = ngx_http_parse_header_line(r, &r->upstream->buffer, 1);

        if (rc == NGX_OK) {

            /* a header line has been parsed successfully */

            h = ngx_list_push(&r->upstream->headers_in.headers);
            if (h == NULL) {
                return NGX_ERROR;
            }

            h->hash = r->header_hash;

            h->key.len = r->header_name_end - r->header_name_start;
            h->value.len = r->header_end - r->header_start;

            h->key.data = ngx_pnalloc(r->pool,
                               h->key.len + 1 + h->value.len + 1 + h->key.len);
            if (h->key.data == NULL) {
                return NGX_ERROR;
            }

            h->value.data = h->key.data + h->key.len + 1;
            h->lowcase_key = h->key.data + h->key.len + 1 + h->value.len + 1;

            ngx_cpystrn(h->key.data, r->header_name_start, h->key.len + 1);
            ngx_cpystrn(h->value.data, r->header_start, h->value.len + 1);

            if (h->key.len == r->lowcase_index) {
                ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);

            } else {
                ngx_strlow(h->lowcase_key, h->key.data, h->key.len);
            }

            hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
                               h->lowcase_key, h->key.len);

            if (hh && hh->handler(r, h, hh->offset) != NGX_OK) {
                return NGX_ERROR;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http proxy header: \"%V: %V\"",
                           &h->key, &h->value);

            continue;
        }

        if (rc == NGX_HTTP_PARSE_HEADER_DONE) {

            /* a whole header has been parsed successfully */

            ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http proxy header done");

            /*
             * if no "Server" and "Date" in header line,
             * then add the special empty headers
             */

            if (r->upstream->headers_in.server == NULL) {
                h = ngx_list_push(&r->upstream->headers_in.headers);
                if (h == NULL) {
                    return NGX_ERROR;
                }

                h->hash = ngx_hash(ngx_hash(ngx_hash(ngx_hash(
                                    ngx_hash('s', 'e'), 'r'), 'v'), 'e'), 'r');

                ngx_str_set(&h->key, "Server");
                ngx_str_null(&h->value);
                h->lowcase_key = (u_char *) "server";
            }

            if (r->upstream->headers_in.date == NULL) {
                h = ngx_list_push(&r->upstream->headers_in.headers);
                if (h == NULL) {
                    return NGX_ERROR;
                }

                h->hash = ngx_hash(ngx_hash(ngx_hash('d', 'a'), 't'), 'e');

                ngx_str_set(&h->key, "Date");
                ngx_str_null(&h->value);
                h->lowcase_key = (u_char *) "date";
            }

            return NGX_OK;
        }

        if (rc == NGX_AGAIN) {
            return NGX_AGAIN;
        }

        /* there was error while a header line parsing */

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent invalid header");

        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
    }
}


static void
ngx_http_proxy_abort_request(ngx_http_request_t *r)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "abort http proxy request");

    return;
}


static void
ngx_http_proxy_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "finalize http proxy request");

    return;
}


static ngx_int_t
ngx_http_proxy_host_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_http_proxy_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (ctx == NULL) {
        v->not_found = 1;
        return NGX_OK;
    }

    v->len = ctx->vars.host_header.len;
    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;
    v->data = ctx->vars.host_header.data;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_port_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_http_proxy_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (ctx == NULL) {
        v->not_found = 1;
        return NGX_OK;
    }

    v->len = ctx->vars.port.len;
    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;
    v->data = ctx->vars.port.data;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_add_x_forwarded_for_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    u_char  *p;

    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;

    if (r->headers_in.x_forwarded_for == NULL) {
        v->len = r->connection->addr_text.len;
        v->data = r->connection->addr_text.data;
        return NGX_OK;
    }

    v->len = r->headers_in.x_forwarded_for->value.len
             + sizeof(", ") - 1 + r->connection->addr_text.len;

    p = ngx_pnalloc(r->pool, v->len);
    if (p == NULL) {
        return NGX_ERROR;
    }

    v->data = p;

    p = ngx_copy(p, r->headers_in.x_forwarded_for->value.data,
                 r->headers_in.x_forwarded_for->value.len);

    *p++ = ','; *p++ = ' ';

    ngx_memcpy(p, r->connection->addr_text.data, r->connection->addr_text.len);

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_internal_body_length_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_http_proxy_ctx_t  *ctx;

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (ctx == NULL) {
        v->not_found = 1;
        return NGX_OK;
    }

    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;

    v->data = ngx_pnalloc(r->connection->pool, NGX_SIZE_T_LEN);

    if (v->data == NULL) {
        return NGX_ERROR;
    }

    v->len = ngx_sprintf(v->data, "%uz", ctx->internal_body_length) - v->data;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_rewrite_redirect(ngx_http_request_t *r, ngx_table_elt_t *h,
    size_t prefix)
{
    ngx_int_t                   rc;
    ngx_uint_t                  i;
    ngx_http_proxy_loc_conf_t  *plcf;
    ngx_http_proxy_redirect_t  *pr;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    pr = plcf->redirects->elts;

    if (pr == NULL) {
        return NGX_DECLINED;
    }

    for (i = 0; i < plcf->redirects->nelts; i++) {
        rc = pr[i].handler(r, h, prefix, &pr[i]);

        if (rc != NGX_DECLINED) {
            return rc;
        }
    }

    return NGX_DECLINED;
}


static ngx_int_t
ngx_http_proxy_rewrite_redirect_text(ngx_http_request_t *r, ngx_table_elt_t *h,
    size_t prefix, ngx_http_proxy_redirect_t *pr)
{
    size_t   len;
    u_char  *data, *p;

    if (pr->redirect.len > h->value.len - prefix
        || ngx_rstrncmp(h->value.data + prefix, pr->redirect.data,
                        pr->redirect.len) != 0)
    {
        return NGX_DECLINED;
    }

    len = pr->replacement.text.len + h->value.len - pr->redirect.len;

    data = ngx_pnalloc(r->pool, len);
    if (data == NULL) {
        return NGX_ERROR;
    }

    p = ngx_copy(data, h->value.data, prefix);

    if (pr->replacement.text.len) {
        p = ngx_copy(p, pr->replacement.text.data, pr->replacement.text.len);
    }

    ngx_memcpy(p, h->value.data + prefix + pr->redirect.len,
               h->value.len - pr->redirect.len - prefix);

    h->value.len = len;
    h->value.data = data;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_rewrite_redirect_vars(ngx_http_request_t *r, ngx_table_elt_t *h,
    size_t prefix, ngx_http_proxy_redirect_t *pr)
{
    size_t                        len;
    u_char                       *data, *p;
    ngx_http_script_code_pt       code;
    ngx_http_script_engine_t      e;
    ngx_http_script_len_code_pt   lcode;

    if (pr->redirect.len > h->value.len - prefix
        || ngx_rstrncmp(h->value.data + prefix, pr->redirect.data,
                        pr->redirect.len) != 0)
    {
        return NGX_DECLINED;
    }

    ngx_memzero(&e, sizeof(ngx_http_script_engine_t));

    e.ip = pr->replacement.vars.lengths;
    e.request = r;

    len = h->value.len - pr->redirect.len;

    while (*(uintptr_t *) e.ip) {
        lcode = *(ngx_http_script_len_code_pt *) e.ip;
        len += lcode(&e);
    }

    data = ngx_pnalloc(r->pool, len);
    if (data == NULL) {
        return NGX_ERROR;
    }

    p = ngx_copy(data, h->value.data, prefix);

    e.ip = pr->replacement.vars.values;
    e.pos = p;

    while (*(uintptr_t *) e.ip) {
        code = *(ngx_http_script_code_pt *) e.ip;
        code(&e);
    }

    ngx_memcpy(e.pos, h->value.data + prefix + pr->redirect.len,
               h->value.len - pr->redirect.len - prefix);

    h->value.len = len;
    h->value.data = data;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

    for (v = ngx_http_proxy_vars; v->name.len; v++) {
        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

        var->get_handler = v->get_handler;
        var->data = v->data;
    }

    return NGX_OK;
}


static void *
ngx_http_proxy_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_proxy_loc_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_proxy_loc_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     conf->upstream.bufs.num = 0;
     *     conf->upstream.ignore_headers = 0;
     *     conf->upstream.next_upstream = 0;
     *     conf->upstream.cache_use_stale = 0;
     *     conf->upstream.cache_methods = 0;
     *     conf->upstream.temp_path = NULL;
     *     conf->upstream.hide_headers_hash = { NULL, 0 };
     *     conf->upstream.uri = { 0, NULL };
     *     conf->upstream.location = NULL;
     *     conf->upstream.store_lengths = NULL;
     *     conf->upstream.store_values = NULL;
     *
     *     conf->method = NULL;
     *     conf->headers_source = NULL;
     *     conf->headers_set_len = NULL;
     *     conf->headers_set = NULL;
     *     conf->headers_set_hash = NULL;
     *     conf->body_set_len = NULL;
     *     conf->body_set = NULL;
     *     conf->body_source = { 0, NULL };
     *     conf->redirects = NULL;
     */

    conf->upstream.store = NGX_CONF_UNSET;
    conf->upstream.store_access = NGX_CONF_UNSET_UINT;
    conf->upstream.buffering = NGX_CONF_UNSET;
    conf->upstream.ignore_client_abort = NGX_CONF_UNSET;

    conf->upstream.connect_timeout = NGX_CONF_UNSET_MSEC;
    conf->upstream.send_timeout = NGX_CONF_UNSET_MSEC;
    conf->upstream.read_timeout = NGX_CONF_UNSET_MSEC;

    conf->upstream.send_lowat = NGX_CONF_UNSET_SIZE;
    conf->upstream.buffer_size = NGX_CONF_UNSET_SIZE;

    conf->upstream.busy_buffers_size_conf = NGX_CONF_UNSET_SIZE;
    conf->upstream.max_temp_file_size_conf = NGX_CONF_UNSET_SIZE;
    conf->upstream.temp_file_write_size_conf = NGX_CONF_UNSET_SIZE;

    conf->upstream.pass_request_headers = NGX_CONF_UNSET;
    conf->upstream.pass_request_body = NGX_CONF_UNSET;

#if (NGX_HTTP_CACHE)
    conf->upstream.cache = NGX_CONF_UNSET_PTR;
    conf->upstream.cache_min_uses = NGX_CONF_UNSET_UINT;
    conf->upstream.cache_bypass = NGX_CONF_UNSET_PTR;
    conf->upstream.no_cache = NGX_CONF_UNSET_PTR;
    conf->upstream.cache_valid = NGX_CONF_UNSET_PTR;
#endif

    conf->upstream.hide_headers = NGX_CONF_UNSET_PTR;
    conf->upstream.pass_headers = NGX_CONF_UNSET_PTR;

    conf->upstream.intercept_errors = NGX_CONF_UNSET;
#if (NGX_HTTP_SSL)
    conf->upstream.ssl_session_reuse = NGX_CONF_UNSET;
#endif

    /* "proxy_cyclic_temp_file" is disabled */
    conf->upstream.cyclic_temp_file = 0;

    conf->redirect = NGX_CONF_UNSET;
    conf->upstream.change_buffering = 1;

    conf->headers_hash_max_size = NGX_CONF_UNSET_UINT;
    conf->headers_hash_bucket_size = NGX_CONF_UNSET_UINT;

    ngx_str_set(&conf->upstream.module, "proxy");

    return conf;
}


static char *
ngx_http_proxy_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_proxy_loc_conf_t *prev = parent;
    ngx_http_proxy_loc_conf_t *conf = child;

    u_char                     *p;
    size_t                      size;
    ngx_keyval_t               *s;
    ngx_hash_init_t             hash;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_proxy_redirect_t  *pr;
    ngx_http_script_compile_t   sc;

    if (conf->upstream.store != 0) {
        ngx_conf_merge_value(conf->upstream.store,
                              prev->upstream.store, 0);

        if (conf->upstream.store_lengths == NULL) {
            conf->upstream.store_lengths = prev->upstream.store_lengths;
            conf->upstream.store_values = prev->upstream.store_values;
        }
    }

    ngx_conf_merge_uint_value(conf->upstream.store_access,
                              prev->upstream.store_access, 0600);

    ngx_conf_merge_value(conf->upstream.buffering,
                              prev->upstream.buffering, 1);

    ngx_conf_merge_value(conf->upstream.ignore_client_abort,
                              prev->upstream.ignore_client_abort, 0);

    ngx_conf_merge_msec_value(conf->upstream.connect_timeout,
                              prev->upstream.connect_timeout, 60000);

    ngx_conf_merge_msec_value(conf->upstream.send_timeout,
                              prev->upstream.send_timeout, 60000);

    ngx_conf_merge_msec_value(conf->upstream.read_timeout,
                              prev->upstream.read_timeout, 60000);

    ngx_conf_merge_size_value(conf->upstream.send_lowat,
                              prev->upstream.send_lowat, 0);

    ngx_conf_merge_size_value(conf->upstream.buffer_size,
                              prev->upstream.buffer_size,
                              (size_t) ngx_pagesize);

    ngx_conf_merge_bufs_value(conf->upstream.bufs, prev->upstream.bufs,
                              8, ngx_pagesize);

    if (conf->upstream.bufs.num < 2) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "there must be at least 2 \"proxy_buffers\"");
        return NGX_CONF_ERROR;
    }


    size = conf->upstream.buffer_size;
    if (size < conf->upstream.bufs.size) {
        size = conf->upstream.bufs.size;
    }


    ngx_conf_merge_size_value(conf->upstream.busy_buffers_size_conf,
                              prev->upstream.busy_buffers_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.busy_buffers_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.busy_buffers_size = 2 * size;
    } else {
        conf->upstream.busy_buffers_size =
                                         conf->upstream.busy_buffers_size_conf;
    }

    if (conf->upstream.busy_buffers_size < size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
             "\"proxy_busy_buffers_size\" must be equal or bigger than "
             "maximum of the value of \"proxy_buffer_size\" and "
             "one of the \"proxy_buffers\"");

        return NGX_CONF_ERROR;
    }

    if (conf->upstream.busy_buffers_size
        > (conf->upstream.bufs.num - 1) * conf->upstream.bufs.size)
    {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
             "\"proxy_busy_buffers_size\" must be less than "
             "the size of all \"proxy_buffers\" minus one buffer");

        return NGX_CONF_ERROR;
    }


    ngx_conf_merge_size_value(conf->upstream.temp_file_write_size_conf,
                              prev->upstream.temp_file_write_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.temp_file_write_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.temp_file_write_size = 2 * size;
    } else {
        conf->upstream.temp_file_write_size =
                                      conf->upstream.temp_file_write_size_conf;
    }

    if (conf->upstream.temp_file_write_size < size) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
             "\"proxy_temp_file_write_size\" must be equal or bigger than "
             "maximum of the value of \"proxy_buffer_size\" and "
             "one of the \"proxy_buffers\"");

        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_size_value(conf->upstream.max_temp_file_size_conf,
                              prev->upstream.max_temp_file_size_conf,
                              NGX_CONF_UNSET_SIZE);

    if (conf->upstream.max_temp_file_size_conf == NGX_CONF_UNSET_SIZE) {
        conf->upstream.max_temp_file_size = 1024 * 1024 * 1024;
    } else {
        conf->upstream.max_temp_file_size =
                                        conf->upstream.max_temp_file_size_conf;
    }

    if (conf->upstream.max_temp_file_size != 0
        && conf->upstream.max_temp_file_size < size)
    {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
             "\"proxy_max_temp_file_size\" must be equal to zero to disable "
             "the temporary files usage or must be equal or bigger than "
             "maximum of the value of \"proxy_buffer_size\" and "
             "one of the \"proxy_buffers\"");

        return NGX_CONF_ERROR;
    }


    ngx_conf_merge_bitmask_value(conf->upstream.ignore_headers,
                              prev->upstream.ignore_headers,
                              NGX_CONF_BITMASK_SET);


    ngx_conf_merge_bitmask_value(conf->upstream.next_upstream,
                              prev->upstream.next_upstream,
                              (NGX_CONF_BITMASK_SET
                               |NGX_HTTP_UPSTREAM_FT_ERROR
                               |NGX_HTTP_UPSTREAM_FT_TIMEOUT));

    if (conf->upstream.next_upstream & NGX_HTTP_UPSTREAM_FT_OFF) {
        conf->upstream.next_upstream = NGX_CONF_BITMASK_SET
                                       |NGX_HTTP_UPSTREAM_FT_OFF;
    }

    if (ngx_conf_merge_path_value(cf, &conf->upstream.temp_path,
                              prev->upstream.temp_path,
                              &ngx_http_proxy_temp_path)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }


#if (NGX_HTTP_CACHE)

    ngx_conf_merge_ptr_value(conf->upstream.cache,
                              prev->upstream.cache, NULL);

    if (conf->upstream.cache && conf->upstream.cache->data == NULL) {
        ngx_shm_zone_t  *shm_zone;

        shm_zone = conf->upstream.cache;

        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "\"proxy_cache\" zone \"%V\" is unknown",
                           &shm_zone->shm.name);

        return NGX_CONF_ERROR;
    }

    ngx_conf_merge_uint_value(conf->upstream.cache_min_uses,
                              prev->upstream.cache_min_uses, 1);

    ngx_conf_merge_bitmask_value(conf->upstream.cache_use_stale,
                              prev->upstream.cache_use_stale,
                              (NGX_CONF_BITMASK_SET
                               |NGX_HTTP_UPSTREAM_FT_OFF));

    if (conf->upstream.cache_methods == 0) {
        conf->upstream.cache_methods = prev->upstream.cache_methods;
    }

    conf->upstream.cache_methods |= NGX_HTTP_GET|NGX_HTTP_HEAD;

    if (conf->upstream.cache_use_stale & NGX_HTTP_UPSTREAM_FT_OFF) {
        conf->upstream.cache_use_stale = NGX_CONF_BITMASK_SET
                                         |NGX_HTTP_UPSTREAM_FT_OFF;
    }

    ngx_conf_merge_ptr_value(conf->upstream.cache_bypass,
                             prev->upstream.cache_bypass, NULL);

    ngx_conf_merge_ptr_value(conf->upstream.no_cache,
                             prev->upstream.no_cache, NULL);

    if (conf->upstream.no_cache && conf->upstream.cache_bypass == NULL) {
        ngx_log_error(NGX_LOG_WARN, cf->log, 0,
             "\"proxy_no_cache\" functionality has been changed in 0.8.46, "
             "now it should be used together with \"proxy_cache_bypass\"");
    }

    ngx_conf_merge_ptr_value(conf->upstream.cache_valid,
                             prev->upstream.cache_valid, NULL);

    if (conf->cache_key.value.data == NULL) {
        conf->cache_key = prev->cache_key;
    }

#endif

    if (conf->method.len == 0) {
        conf->method = prev->method;

    } else {
        conf->method.data[conf->method.len] = ' ';
        conf->method.len++;
    }

    ngx_conf_merge_value(conf->upstream.pass_request_headers,
                              prev->upstream.pass_request_headers, 1);
    ngx_conf_merge_value(conf->upstream.pass_request_body,
                              prev->upstream.pass_request_body, 1);

    ngx_conf_merge_value(conf->upstream.intercept_errors,
                              prev->upstream.intercept_errors, 0);

#if (NGX_HTTP_SSL)
    ngx_conf_merge_value(conf->upstream.ssl_session_reuse,
                              prev->upstream.ssl_session_reuse, 1);
#endif

    ngx_conf_merge_value(conf->redirect, prev->redirect, 1);

    if (conf->redirect) {

        if (conf->redirects == NULL) {
            conf->redirects = prev->redirects;
        }

        if (conf->redirects == NULL && conf->url.data) {

            conf->redirects = ngx_array_create(cf->pool, 1,
                                            sizeof(ngx_http_proxy_redirect_t));
            if (conf->redirects == NULL) {
                return NGX_CONF_ERROR;
            }

            pr = ngx_array_push(conf->redirects);
            if (pr == NULL) {
                return NGX_CONF_ERROR;
            }

            pr->handler = ngx_http_proxy_rewrite_redirect_text;

            if (conf->vars.uri.len) {
                pr->redirect = conf->url;
                pr->replacement.text = conf->location;

            } else {
                pr->redirect.len = conf->url.len + sizeof("/") - 1;

                p = ngx_pnalloc(cf->pool, pr->redirect.len);
                if (p == NULL) {
                    return NGX_CONF_ERROR;
                }

                pr->redirect.data = p;

                p = ngx_cpymem(p, conf->url.data, conf->url.len);
                *p = '/';

                ngx_str_set(&pr->replacement.text, "/");
            }
        }
    }

#if (NGX_HTTP_SSL)
    if (conf->upstream.ssl == NULL) {
        conf->upstream.ssl = prev->upstream.ssl;
    }
#endif

    ngx_conf_merge_uint_value(conf->headers_hash_max_size,
                              prev->headers_hash_max_size, 512);

    ngx_conf_merge_uint_value(conf->headers_hash_bucket_size,
                              prev->headers_hash_bucket_size, 64);

    conf->headers_hash_bucket_size = ngx_align(conf->headers_hash_bucket_size,
                                               ngx_cacheline_size);

    hash.max_size = conf->headers_hash_max_size;
    hash.bucket_size = conf->headers_hash_bucket_size;
    hash.name = "proxy_headers_hash";

    if (ngx_http_upstream_hide_headers_hash(cf, &conf->upstream,
            &prev->upstream, ngx_http_proxy_hide_headers, &hash)
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    if (conf->upstream.upstream == NULL) {
        conf->upstream.upstream = prev->upstream.upstream;
        conf->vars = prev->vars;
    }

    if (conf->proxy_lengths == NULL) {
        conf->proxy_lengths = prev->proxy_lengths;
        conf->proxy_values = prev->proxy_values;
    }

    if (conf->upstream.upstream || conf->proxy_lengths) {
        clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
        if (clcf->handler == NULL && clcf->lmt_excpt) {
            clcf->handler = ngx_http_proxy_handler;
            conf->location = prev->location;
        }
    }

    if (conf->body_source.data == NULL) {
        conf->body_source = prev->body_source;
        conf->body_set_len = prev->body_set_len;
        conf->body_set = prev->body_set;
    }

    if (conf->body_source.data && conf->body_set_len == NULL) {

        ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

        sc.cf = cf;
        sc.source = &conf->body_source;
        sc.flushes = &conf->flushes;
        sc.lengths = &conf->body_set_len;
        sc.values = &conf->body_set;
        sc.complete_lengths = 1;
        sc.complete_values = 1;

        if (ngx_http_script_compile(&sc) != NGX_OK) {
            return NGX_CONF_ERROR;
        }

        if (conf->headers_source == NULL) {
            conf->headers_source = ngx_array_create(cf->pool, 4,
                                                    sizeof(ngx_keyval_t));
            if (conf->headers_source == NULL) {
                return NGX_CONF_ERROR;
            }
        }

        s = ngx_array_push(conf->headers_source);
        if (s == NULL) {
            return NGX_CONF_ERROR;
        }

        ngx_str_set(&s->key, "Content-Length");
        ngx_str_set(&s->value, "$proxy_internal_body_length");
    }

    if (ngx_http_proxy_merge_headers(cf, conf, prev) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static ngx_int_t
ngx_http_proxy_merge_headers(ngx_conf_t *cf, ngx_http_proxy_loc_conf_t *conf,
    ngx_http_proxy_loc_conf_t *prev)
{
    u_char                       *p;
    size_t                        size;
    uintptr_t                    *code;
    ngx_uint_t                    i;
    ngx_array_t                   headers_names;
    ngx_keyval_t                 *src, *s, *h;
    ngx_hash_key_t               *hk;
    ngx_hash_init_t               hash;
    ngx_http_script_compile_t     sc;
    ngx_http_script_copy_code_t  *copy;

    if (conf->headers_source == NULL) {
        conf->flushes = prev->flushes;
        conf->headers_set_len = prev->headers_set_len;
        conf->headers_set = prev->headers_set;
        conf->headers_set_hash = prev->headers_set_hash;
        conf->headers_source = prev->headers_source;
    }

    if (conf->headers_set_hash.buckets
#if (NGX_HTTP_CACHE)
        && ((conf->upstream.cache == NULL) == (prev->upstream.cache == NULL))
#endif
       )
    {
        return NGX_OK;
    }


    if (ngx_array_init(&headers_names, cf->temp_pool, 4, sizeof(ngx_hash_key_t))
        != NGX_OK)
    {
        return NGX_ERROR;
    }

    if (conf->headers_source == NULL) {
        conf->headers_source = ngx_array_create(cf->pool, 4,
                                                sizeof(ngx_keyval_t));
        if (conf->headers_source == NULL) {
            return NGX_ERROR;
        }
    }

    conf->headers_set_len = ngx_array_create(cf->pool, 64, 1);
    if (conf->headers_set_len == NULL) {
        return NGX_ERROR;
    }

    conf->headers_set = ngx_array_create(cf->pool, 512, 1);
    if (conf->headers_set == NULL) {
        return NGX_ERROR;
    }


    src = conf->headers_source->elts;

#if (NGX_HTTP_CACHE)

    h = conf->upstream.cache ? ngx_http_proxy_cache_headers:
                               ngx_http_proxy_headers;
#else

    h = ngx_http_proxy_headers;

#endif

    while (h->key.len) {

        for (i = 0; i < conf->headers_source->nelts; i++) {
            if (ngx_strcasecmp(h->key.data, src[i].key.data) == 0) {
                goto next;
            }
        }

        s = ngx_array_push(conf->headers_source);
        if (s == NULL) {
            return NGX_ERROR;
        }

        *s = *h;

        src = conf->headers_source->elts;

    next:

        h++;
    }


    src = conf->headers_source->elts;
    for (i = 0; i < conf->headers_source->nelts; i++) {

        hk = ngx_array_push(&headers_names);
        if (hk == NULL) {
            return NGX_ERROR;
        }

        hk->key = src[i].key;
        hk->key_hash = ngx_hash_key_lc(src[i].key.data, src[i].key.len);
        hk->value = (void *) 1;

        if (src[i].value.len == 0) {
            continue;
        }

        if (ngx_http_script_variables_count(&src[i].value) == 0) {
            copy = ngx_array_push_n(conf->headers_set_len,
                                    sizeof(ngx_http_script_copy_code_t));
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = (ngx_http_script_code_pt)
                                                 ngx_http_script_copy_len_code;
            copy->len = src[i].key.len + sizeof(": ") - 1
                        + src[i].value.len + sizeof(CRLF) - 1;


            size = (sizeof(ngx_http_script_copy_code_t)
                       + src[i].key.len + sizeof(": ") - 1
                       + src[i].value.len + sizeof(CRLF) - 1
                       + sizeof(uintptr_t) - 1)
                    & ~(sizeof(uintptr_t) - 1);

            copy = ngx_array_push_n(conf->headers_set, size);
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = ngx_http_script_copy_code;
            copy->len = src[i].key.len + sizeof(": ") - 1
                        + src[i].value.len + sizeof(CRLF) - 1;

            p = (u_char *) copy + sizeof(ngx_http_script_copy_code_t);

            p = ngx_cpymem(p, src[i].key.data, src[i].key.len);
            *p++ = ':'; *p++ = ' ';
            p = ngx_cpymem(p, src[i].value.data, src[i].value.len);
            *p++ = CR; *p = LF;

        } else {
            copy = ngx_array_push_n(conf->headers_set_len,
                                    sizeof(ngx_http_script_copy_code_t));
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = (ngx_http_script_code_pt)
                                                 ngx_http_script_copy_len_code;
            copy->len = src[i].key.len + sizeof(": ") - 1;


            size = (sizeof(ngx_http_script_copy_code_t)
                    + src[i].key.len + sizeof(": ") - 1 + sizeof(uintptr_t) - 1)
                    & ~(sizeof(uintptr_t) - 1);

            copy = ngx_array_push_n(conf->headers_set, size);
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = ngx_http_script_copy_code;
            copy->len = src[i].key.len + sizeof(": ") - 1;

            p = (u_char *) copy + sizeof(ngx_http_script_copy_code_t);
            p = ngx_cpymem(p, src[i].key.data, src[i].key.len);
            *p++ = ':'; *p = ' ';


            ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

            sc.cf = cf;
            sc.source = &src[i].value;
            sc.flushes = &conf->flushes;
            sc.lengths = &conf->headers_set_len;
            sc.values = &conf->headers_set;

            if (ngx_http_script_compile(&sc) != NGX_OK) {
                return NGX_ERROR;
            }


            copy = ngx_array_push_n(conf->headers_set_len,
                                    sizeof(ngx_http_script_copy_code_t));
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = (ngx_http_script_code_pt)
                                                 ngx_http_script_copy_len_code;
            copy->len = sizeof(CRLF) - 1;


            size = (sizeof(ngx_http_script_copy_code_t)
                    + sizeof(CRLF) - 1 + sizeof(uintptr_t) - 1)
                    & ~(sizeof(uintptr_t) - 1);

            copy = ngx_array_push_n(conf->headers_set, size);
            if (copy == NULL) {
                return NGX_ERROR;
            }

            copy->code = ngx_http_script_copy_code;
            copy->len = sizeof(CRLF) - 1;

            p = (u_char *) copy + sizeof(ngx_http_script_copy_code_t);
            *p++ = CR; *p = LF;
        }

        code = ngx_array_push_n(conf->headers_set_len, sizeof(uintptr_t));
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;

        code = ngx_array_push_n(conf->headers_set, sizeof(uintptr_t));
        if (code == NULL) {
            return NGX_ERROR;
        }

        *code = (uintptr_t) NULL;
    }

    code = ngx_array_push_n(conf->headers_set_len, sizeof(uintptr_t));
    if (code == NULL) {
        return NGX_ERROR;
    }

    *code = (uintptr_t) NULL;


    hash.hash = &conf->headers_set_hash;
    hash.key = ngx_hash_key_lc;
    hash.max_size = conf->headers_hash_max_size;
    hash.bucket_size = conf->headers_hash_bucket_size;
    hash.name = "proxy_headers_hash";
    hash.pool = cf->pool;
    hash.temp_pool = NULL;

    return ngx_hash_init(&hash, headers_names.elts, headers_names.nelts);
}


static char *
ngx_http_proxy_pass(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_proxy_loc_conf_t *plcf = conf;

    size_t                      add;
    u_short                     port;
    ngx_str_t                  *value, *url;
    ngx_url_t                   u;
    ngx_uint_t                  n;
    ngx_http_core_loc_conf_t   *clcf;
    ngx_http_script_compile_t   sc;

    if (plcf->upstream.upstream || plcf->proxy_lengths) {
        return "is duplicate";
    }

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);

    clcf->handler = ngx_http_proxy_handler;

    if (clcf->name.data[clcf->name.len - 1] == '/') {
        clcf->auto_redirect = 1;
    }

    value = cf->args->elts;

    url = &value[1];

    n = ngx_http_script_variables_count(url);

    if (n) {

        ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

        sc.cf = cf;
        sc.source = url;
        sc.lengths = &plcf->proxy_lengths;
        sc.values = &plcf->proxy_values;
        sc.variables = n;
        sc.complete_lengths = 1;
        sc.complete_values = 1;

        if (ngx_http_script_compile(&sc) != NGX_OK) {
            return NGX_CONF_ERROR;
        }

#if (NGX_HTTP_SSL)
        if (ngx_http_proxy_set_ssl(cf, plcf) != NGX_OK) {
            return NGX_CONF_ERROR;
        }
#endif

        return NGX_CONF_OK;
    }

    if (ngx_strncasecmp(url->data, (u_char *) "http://", 7) == 0) {
        add = 7;
        port = 80;

    } else if (ngx_strncasecmp(url->data, (u_char *) "https://", 8) == 0) {

#if (NGX_HTTP_SSL)
        if (ngx_http_proxy_set_ssl(cf, plcf) != NGX_OK) {
            return NGX_CONF_ERROR;
        }

        add = 8;
        port = 443;
#else
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "https protocol requires SSL support");
        return NGX_CONF_ERROR;
#endif

    } else {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid URL prefix");
        return NGX_CONF_ERROR;
    }

    ngx_memzero(&u, sizeof(ngx_url_t));

    u.url.len = url->len - add;
    u.url.data = url->data + add;
    u.default_port = port;
    u.uri_part = 1;
    u.no_resolve = 1;

    plcf->upstream.upstream = ngx_http_upstream_add(cf, &u, 0);
    if (plcf->upstream.upstream == NULL) {
        return NGX_CONF_ERROR;
    }

    plcf->vars.schema.len = add;
    plcf->vars.schema.data = url->data;
    plcf->vars.key_start = plcf->vars.schema;

    ngx_http_proxy_set_vars(&u, &plcf->vars);

    plcf->location = clcf->name;

    if (clcf->named
#if (NGX_PCRE)
        || clcf->regex
#endif
        || clcf->noname)
    {
        if (plcf->vars.uri.len) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "\"proxy_pass\" may not have URI part in "
                               "location given by regular expression, "
                               "or inside named location, "
                               "or inside the \"if\" statement, "
                               "or inside the \"limit_except\" block");
            return NGX_CONF_ERROR;
        }

        plcf->location.len = 0;
    }

    plcf->url = *url;

    return NGX_CONF_OK;
}


static char *
ngx_http_proxy_redirect(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_proxy_loc_conf_t *plcf = conf;

    u_char                     *p;
    ngx_str_t                  *value;
    ngx_array_t                *vars_lengths, *vars_values;
    ngx_http_script_compile_t   sc;
    ngx_http_proxy_redirect_t  *pr;

    if (plcf->redirect == 0) {
        return NGX_CONF_OK;
    }

    value = cf->args->elts;

    if (cf->args->nelts == 2) {
        if (ngx_strcmp(value[1].data, "off") == 0) {
            plcf->redirect = 0;
            plcf->redirects = NULL;
            return NGX_CONF_OK;
        }

        if (ngx_strcmp(value[1].data, "false") == 0) {
            ngx_conf_log_error(NGX_LOG_ERR, cf, 0,
                           "invalid parameter \"false\", use \"off\" instead");
            plcf->redirect = 0;
            plcf->redirects = NULL;
            return NGX_CONF_OK;
        }

        if (ngx_strcmp(value[1].data, "default") != 0) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "invalid parameter \"%V\"", &value[1]);
            return NGX_CONF_ERROR;
        }
    }

    if (plcf->redirects == NULL) {
        plcf->redirects = ngx_array_create(cf->pool, 1,
                                           sizeof(ngx_http_proxy_redirect_t));
        if (plcf->redirects == NULL) {
            return NGX_CONF_ERROR;
        }
    }

    pr = ngx_array_push(plcf->redirects);
    if (pr == NULL) {
        return NGX_CONF_ERROR;
    }

    if (ngx_strcmp(value[1].data, "default") == 0) {
        if (plcf->proxy_lengths) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "\"proxy_redirect default\" may not be used "
                               "with \"proxy_pass\" directive with variables");
            return NGX_CONF_ERROR;
        }

        if (plcf->url.data == NULL) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "\"proxy_redirect default\" must go "
                               "after the \"proxy_pass\" directive");
            return NGX_CONF_ERROR;
        }

        pr->handler = ngx_http_proxy_rewrite_redirect_text;

        if (plcf->vars.uri.len) {
            pr->redirect = plcf->url;
            pr->replacement.text = plcf->location;

        } else {
            pr->redirect.len = plcf->url.len + sizeof("/") - 1;

            p = ngx_pnalloc(cf->pool, pr->redirect.len);
            if (p == NULL) {
                return NGX_CONF_ERROR;
            }

            pr->redirect.data = p;

            p = ngx_cpymem(p, plcf->url.data, plcf->url.len);
            *p = '/';

            ngx_str_set(&pr->replacement.text, "/");
        }

        return NGX_CONF_OK;
    }

    if (ngx_http_script_variables_count(&value[2]) == 0) {
        pr->handler = ngx_http_proxy_rewrite_redirect_text;
        pr->redirect = value[1];
        pr->replacement.text = value[2];

        return NGX_CONF_OK;
    }

    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    vars_lengths = NULL;
    vars_values = NULL;

    sc.cf = cf;
    sc.source = &value[2];
    sc.lengths = &vars_lengths;
    sc.values = &vars_values;
    sc.complete_lengths = 1;
    sc.complete_values = 1;

    if (ngx_http_script_compile(&sc) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    pr->handler = ngx_http_proxy_rewrite_redirect_vars;
    pr->redirect = value[1];
    pr->replacement.vars.lengths = vars_lengths->elts;
    pr->replacement.vars.values = vars_values->elts;

    return NGX_CONF_OK;
}


static char *
ngx_http_proxy_store(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_proxy_loc_conf_t *plcf = conf;

    ngx_str_t                  *value;
    ngx_http_script_compile_t   sc;

    if (plcf->upstream.store != NGX_CONF_UNSET
        || plcf->upstream.store_lengths)
    {
        return "is duplicate";
    }

    value = cf->args->elts;

    if (ngx_strcmp(value[1].data, "off") == 0) {
        plcf->upstream.store = 0;
        return NGX_CONF_OK;
    }

#if (NGX_HTTP_CACHE)

    if (plcf->upstream.cache != NGX_CONF_UNSET_PTR
        && plcf->upstream.cache != NULL)
    {
        return "is incompatible with \"proxy_cache\"";
    }

#endif

    if (ngx_strcmp(value[1].data, "on") == 0) {
        plcf->upstream.store = 1;
        return NGX_CONF_OK;
    }

    /* include the terminating '\0' into script */
    value[1].len++;

    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    sc.cf = cf;
    sc.source = &value[1];
    sc.lengths = &plcf->upstream.store_lengths;
    sc.values = &plcf->upstream.store_values;
    sc.variables = ngx_http_script_variables_count(&value[1]);
    sc.complete_lengths = 1;
    sc.complete_values = 1;

    if (ngx_http_script_compile(&sc) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


#if (NGX_HTTP_CACHE)

static char *
ngx_http_proxy_cache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_proxy_loc_conf_t *plcf = conf;

    ngx_str_t  *value;

    value = cf->args->elts;

    if (plcf->upstream.cache != NGX_CONF_UNSET_PTR) {
        return "is duplicate";
    }

    if (ngx_strcmp(value[1].data, "off") == 0) {
        plcf->upstream.cache = NULL;
        return NGX_CONF_OK;
    }

    if (plcf->upstream.store > 0 || plcf->upstream.store_lengths) {
        return "is incompatible with \"proxy_store\"";
    }

    plcf->upstream.cache = ngx_shared_memory_add(cf, &value[1], 0,
                                                 &ngx_http_proxy_module);
    if (plcf->upstream.cache == NULL) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}


static char *
ngx_http_proxy_cache_key(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_proxy_loc_conf_t *plcf = conf;

    ngx_str_t                         *value;
    ngx_http_compile_complex_value_t   ccv;

    value = cf->args->elts;

    if (plcf->cache_key.value.len) {
        return "is duplicate";
    }

    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = &plcf->cache_key;

    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}

#endif


static char *
ngx_http_proxy_lowat_check(ngx_conf_t *cf, void *post, void *data)
{
#if (NGX_FREEBSD)
    ssize_t *np = data;

    if ((u_long) *np >= ngx_freebsd_net_inet_tcp_sendspace) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "\"proxy_send_lowat\" must be less than %d "
                           "(sysctl net.inet.tcp.sendspace)",
                           ngx_freebsd_net_inet_tcp_sendspace);

        return NGX_CONF_ERROR;
    }

#elif !(NGX_HAVE_SO_SNDLOWAT)
    ssize_t *np = data;

    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                       "\"proxy_send_lowat\" is not supported, ignored");

    *np = 0;

#endif

    return NGX_CONF_OK;
}


#if (NGX_HTTP_SSL)

static ngx_int_t
ngx_http_proxy_set_ssl(ngx_conf_t *cf, ngx_http_proxy_loc_conf_t *plcf)
{
    ngx_pool_cleanup_t  *cln;

    plcf->upstream.ssl = ngx_pcalloc(cf->pool, sizeof(ngx_ssl_t));
    if (plcf->upstream.ssl == NULL) {
        return NGX_ERROR;
    }

    plcf->upstream.ssl->log = cf->log;

    if (ngx_ssl_create(plcf->upstream.ssl,
                       NGX_SSL_SSLv2|NGX_SSL_SSLv3|NGX_SSL_TLSv1, NULL)
        != NGX_OK)
    {
        return NGX_ERROR;
    }

    cln = ngx_pool_cleanup_add(cf->pool, 0);
    if (cln == NULL) {
        return NGX_ERROR;
    }

    cln->handler = ngx_ssl_cleanup_ctx;
    cln->data = plcf->upstream.ssl;

    return NGX_OK;
}

#endif


static void
ngx_http_proxy_set_vars(ngx_url_t *u, ngx_http_proxy_vars_t *v)
{
    if (u->family != AF_UNIX) {

        if (u->no_port || u->port == u->default_port) {

            v->host_header = u->host;

            if (u->default_port == 80) {
                ngx_str_set(&v->port, "80");

            } else {
                ngx_str_set(&v->port, "443");
            }

        } else {
            v->host_header.len = u->host.len + 1 + u->port_text.len;
            v->host_header.data = u->host.data;
            v->port = u->port_text;
        }

        v->key_start.len += v->host_header.len;

    } else {
        ngx_str_set(&v->host_header, "localhost");
        ngx_str_null(&v->port);
        v->key_start.len += sizeof("unix:") - 1 + u->host.len + 1;
    }

    v->uri = u->uri;
}