ngx_http_proxy_module.h

/*
 * Copyright (C) Danila Poyarkov
 *
 * Based on ngx_http_proxy_module.c
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 *
 * Extracted from nginx 1.26.3
 */


#ifndef _NGX_HTTP_PROXY_MODULE_H_INCLUDED_
#define _NGX_HTTP_PROXY_MODULE_H_INCLUDED_


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


#define  NGX_HTTP_PROXY_COOKIE_SECURE           0x0001
#define  NGX_HTTP_PROXY_COOKIE_SECURE_ON        0x0002
#define  NGX_HTTP_PROXY_COOKIE_SECURE_OFF       0x0004
#define  NGX_HTTP_PROXY_COOKIE_HTTPONLY         0x0008
#define  NGX_HTTP_PROXY_COOKIE_HTTPONLY_ON      0x0010
#define  NGX_HTTP_PROXY_COOKIE_HTTPONLY_OFF     0x0020
#define  NGX_HTTP_PROXY_COOKIE_SAMESITE         0x0040
#define  NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT  0x0080
#define  NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX     0x0100
#define  NGX_HTTP_PROXY_COOKIE_SAMESITE_NONE    0x0200
#define  NGX_HTTP_PROXY_COOKIE_SAMESITE_OFF     0x0400


typedef struct {
    ngx_array_t                    caches;  /* ngx_http_file_cache_t * */
} ngx_http_proxy_main_conf_t;


typedef struct ngx_http_proxy_rewrite_s  ngx_http_proxy_rewrite_t;

typedef ngx_int_t (*ngx_http_proxy_rewrite_pt)(ngx_http_request_t *r,
    ngx_str_t *value, size_t prefix, size_t len,
    ngx_http_proxy_rewrite_t *pr);

struct ngx_http_proxy_rewrite_s {
    ngx_http_proxy_rewrite_pt      handler;

    union {
        ngx_http_complex_value_t   complex;
#if (NGX_PCRE)
        ngx_http_regex_t          *regex;
#endif
    } pattern;

    ngx_http_complex_value_t       replacement;
};


typedef struct {
    union {
        ngx_http_complex_value_t   complex;
#if (NGX_PCRE)
        ngx_http_regex_t          *regex;
#endif
    } cookie;

    ngx_array_t                    flags_values;
    ngx_uint_t                     regex;
} ngx_http_proxy_cookie_flags_t;


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_array_t                   *flushes;
    ngx_array_t                   *lengths;
    ngx_array_t                   *values;
    ngx_hash_t                     hash;
} ngx_http_proxy_headers_t;


typedef struct {
    ngx_http_upstream_conf_t       upstream;

    ngx_array_t                   *body_flushes;
    ngx_array_t                   *body_lengths;
    ngx_array_t                   *body_values;
    ngx_str_t                      body_source;

    ngx_http_proxy_headers_t       headers;
#if (NGX_HTTP_CACHE)
    ngx_http_proxy_headers_t       headers_cache;
#endif
    ngx_array_t                   *headers_source;

    ngx_array_t                   *proxy_lengths;
    ngx_array_t                   *proxy_values;

    ngx_array_t                   *redirects;
    ngx_array_t                   *cookie_domains;
    ngx_array_t                   *cookie_paths;
    ngx_array_t                   *cookie_flags;

    ngx_http_complex_value_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                     http_version;

    ngx_uint_t                     headers_hash_max_size;
    ngx_uint_t                     headers_hash_bucket_size;

#if (NGX_HTTP_SSL)
    ngx_uint_t                     ssl;
    ngx_uint_t                     ssl_protocols;
    ngx_str_t                      ssl_ciphers;
    ngx_uint_t                     ssl_verify_depth;
    ngx_str_t                      ssl_trusted_certificate;
    ngx_str_t                      ssl_crl;
    ngx_array_t                   *ssl_conf_commands;
#endif
} ngx_http_proxy_loc_conf_t;


typedef struct {
    ngx_http_status_t              status;
    ngx_http_chunked_t             chunked;
    ngx_http_proxy_vars_t          vars;
    off_t                          internal_body_length;

    ngx_chain_t                   *free;
    ngx_chain_t                   *busy;

    unsigned                       head:1;
    unsigned                       internal_chunked:1;
    unsigned                       header_sent:1;
} ngx_http_proxy_ctx_t;




extern ngx_module_t  ngx_http_proxy_module;


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_body_output_filter(void *data,
    ngx_chain_t *in);
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 ngx_int_t ngx_http_proxy_input_filter_init(void *data);
static ngx_int_t ngx_http_proxy_copy_filter(ngx_event_pipe_t *p,
    ngx_buf_t *buf);
static ngx_int_t ngx_http_proxy_chunked_filter(ngx_event_pipe_t *p,
    ngx_buf_t *buf);
static ngx_int_t ngx_http_proxy_non_buffered_copy_filter(void *data,
    ssize_t bytes);
static ngx_int_t ngx_http_proxy_non_buffered_chunked_filter(void *data,
    ssize_t bytes);
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_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_internal_chunked_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_rewrite_cookie(ngx_http_request_t *r,
    ngx_table_elt_t *h);
static ngx_int_t ngx_http_proxy_parse_cookie(ngx_str_t *value,
    ngx_array_t *attrs);
static ngx_int_t ngx_http_proxy_rewrite_cookie_value(ngx_http_request_t *r,
    ngx_str_t *value, ngx_array_t *rewrites);
static ngx_int_t ngx_http_proxy_rewrite_cookie_flags(ngx_http_request_t *r,
    ngx_array_t *attrs, ngx_array_t *flags);
static ngx_int_t ngx_http_proxy_edit_cookie_flags(ngx_http_request_t *r,
    ngx_array_t *attrs, ngx_uint_t flags);
static ngx_int_t ngx_http_proxy_rewrite_complex_handler(ngx_http_request_t *r,
    ngx_str_t *value, size_t prefix, size_t len,
    ngx_http_proxy_rewrite_t *pr);
static ngx_int_t ngx_http_proxy_rewrite_domain_handler(ngx_http_request_t *r,
    ngx_str_t *value, size_t prefix, size_t len,
    ngx_http_proxy_rewrite_t *pr);
#if (NGX_PCRE)
static ngx_int_t ngx_http_proxy_rewrite_regex_handler(ngx_http_request_t *r,
    ngx_str_t *value, size_t prefix, size_t len,
    ngx_http_proxy_rewrite_t *pr);
#endif
static ngx_int_t ngx_http_proxy_rewrite(ngx_http_request_t *r,
    ngx_str_t *value, size_t prefix, size_t len, ngx_str_t *replacement);
static void ngx_http_proxy_set_vars(ngx_url_t *u, ngx_http_proxy_vars_t *v);


static char  ngx_http_proxy_version[] = " HTTP/1.0" CRLF;
static char  ngx_http_proxy_version_11[] = " HTTP/1.1" CRLF;


static ngx_conf_bitmask_t  ngx_http_proxy_cookie_flags_masks[] __attribute__((unused)) = {

    { ngx_string("secure"),
      NGX_HTTP_PROXY_COOKIE_SECURE|NGX_HTTP_PROXY_COOKIE_SECURE_ON },

    { ngx_string("nosecure"),
      NGX_HTTP_PROXY_COOKIE_SECURE|NGX_HTTP_PROXY_COOKIE_SECURE_OFF },

    { ngx_string("httponly"),
      NGX_HTTP_PROXY_COOKIE_HTTPONLY|NGX_HTTP_PROXY_COOKIE_HTTPONLY_ON },

    { ngx_string("nohttponly"),
      NGX_HTTP_PROXY_COOKIE_HTTPONLY|NGX_HTTP_PROXY_COOKIE_HTTPONLY_OFF },

    { ngx_string("samesite=strict"),
      NGX_HTTP_PROXY_COOKIE_SAMESITE|NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT },

    { ngx_string("samesite=lax"),
      NGX_HTTP_PROXY_COOKIE_SAMESITE|NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX },

    { ngx_string("samesite=none"),
      NGX_HTTP_PROXY_COOKIE_SAMESITE|NGX_HTTP_PROXY_COOKIE_SAMESITE_NONE },

    { ngx_string("nosamesite"),
      NGX_HTTP_PROXY_COOKIE_SAMESITE|NGX_HTTP_PROXY_COOKIE_SAMESITE_OFF },

    { ngx_null_string, 0 }
};


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;
        }
    }

    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) {
        u->resolved->sockaddr = url.addrs[0].sockaddr;
        u->resolved->socklen = url.addrs[0].socklen;
        u->resolved->name = url.addrs[0].name;
        u->resolved->naddrs = 1;
    }

    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;
}


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.data) {

        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 && ctx->vars.uri.len) {

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

        return NGX_OK;

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


static ngx_int_t
ngx_http_proxy_create_request(ngx_http_request_t *r)
{
    size_t                        len, uri_len, loc_len, body_len,
                                  key_len, val_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_proxy_headers_t     *headers;
    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 (NGX_HTTP_CACHE)
    headers = u->cacheable ? &plcf->headers_cache : &plcf->headers;
#else
    headers = &plcf->headers;
#endif

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

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

    } else {
        method = r->method_name;
    }

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (method.len == 4
        && ngx_strncasecmp(method.data, (u_char *) "HEAD", 4) == 0)
    {
        ctx->head = 1;
    }

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

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

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

    } else if (ctx->vars.uri.len == 0 && r->valid_unparsed_uri) {
        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->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_memzero(&le, sizeof(ngx_http_script_engine_t));

    ngx_http_script_flush_no_cacheable_variables(r, plcf->body_flushes);
    ngx_http_script_flush_no_cacheable_variables(r, headers->flushes);

    if (plcf->body_lengths) {
        le.ip = plcf->body_lengths->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;

    } else if (r->headers_in.chunked && r->reading_body) {
        ctx->internal_body_length = -1;
        ctx->internal_chunked = 1;

    } else {
        ctx->internal_body_length = r->headers_in.content_length_n;
    }

    le.ip = headers->lengths->elts;
    le.request = r;
    le.flushed = 1;

    while (*(uintptr_t *) le.ip) {

        lcode = *(ngx_http_script_len_code_pt *) le.ip;
        key_len = lcode(&le);

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

        if (val_len == 0) {
            continue;
        }

        len += key_len + sizeof(": ") - 1 + val_len + sizeof(CRLF) - 1;
    }


    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(&headers->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);
    *b->last++ = ' ';

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

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

    if (plcf->http_version == NGX_HTTP_VERSION_11) {
        b->last = ngx_cpymem(b->last, ngx_http_proxy_version_11,
                             sizeof(ngx_http_proxy_version_11) - 1);

    } else {
        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 = headers->values->elts;
    e.pos = b->last;
    e.request = r;
    e.flushed = 1;

    le.ip = headers->lengths->elts;

    while (*(uintptr_t *) le.ip) {

        lcode = *(ngx_http_script_len_code_pt *) le.ip;
        (void) lcode(&le);

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

        if (val_len == 0) {
            e.skip = 1;

            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);

            e.skip = 0;

            continue;
        }

        code = *(ngx_http_script_code_pt *) e.ip;
        code((ngx_http_script_engine_t *) &e);

        *e.pos++ = ':'; *e.pos++ = ' ';

        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);

        *e.pos++ = CR; *e.pos++ = LF;
    }

    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(&headers->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_values) {
        e.ip = plcf->body_values->elts;
        e.pos = b->last;
        e.skip = 0;

        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 (r->request_body_no_buffering) {

        u->request_bufs = cl;

        if (ctx->internal_chunked) {
            u->output.output_filter = ngx_http_proxy_body_output_filter;
            u->output.filter_ctx = r;
        }

    } else if (plcf->body_values == 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;
    ctx->chunked.state = 0;

    r->upstream->process_header = ngx_http_proxy_process_status_line;
    r->upstream->pipe->input_filter = ngx_http_proxy_copy_filter;
    r->upstream->input_filter = ngx_http_proxy_non_buffered_copy_filter;
    r->state = 0;

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_body_output_filter(void *data, ngx_chain_t *in)
{
    ngx_http_request_t  *r = data;

    off_t                  size;
    u_char                *chunk;
    ngx_int_t              rc;
    ngx_buf_t             *b;
    ngx_chain_t           *out, *cl, *tl, **ll, **fl;
    ngx_http_proxy_ctx_t  *ctx;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "proxy output filter");

    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

    if (in == NULL) {
        out = in;
        goto out;
    }

    out = NULL;
    ll = &out;

    if (!ctx->header_sent) {
        /* first buffer contains headers, pass it unmodified */

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

        ctx->header_sent = 1;

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

        tl->buf = in->buf;
        *ll = tl;
        ll = &tl->next;

        in = in->next;

        if (in == NULL) {
            tl->next = NULL;
            goto out;
        }
    }

    size = 0;
    cl = in;
    fl = ll;

    for ( ;; ) {
        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "proxy output chunk: %O", ngx_buf_size(cl->buf));

        size += ngx_buf_size(cl->buf);

        if (cl->buf->flush
            || cl->buf->sync
            || ngx_buf_in_memory(cl->buf)
            || cl->buf->in_file)
        {
            tl = ngx_alloc_chain_link(r->pool);
            if (tl == NULL) {
                return NGX_ERROR;
            }

            tl->buf = cl->buf;
            *ll = tl;
            ll = &tl->next;
        }

        if (cl->next == NULL) {
            break;
        }

        cl = cl->next;
    }

    if (size) {
        tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        b = tl->buf;
        chunk = b->start;

        if (chunk == NULL) {
            /* the "0000000000000000" is 64-bit hexadecimal string */

            chunk = ngx_palloc(r->pool, sizeof("0000000000000000" CRLF) - 1);
            if (chunk == NULL) {
                return NGX_ERROR;
            }

            b->start = chunk;
            b->end = chunk + sizeof("0000000000000000" CRLF) - 1;
        }

        b->tag = (ngx_buf_tag_t) &ngx_http_proxy_body_output_filter;
        b->memory = 0;
        b->temporary = 1;
        b->pos = chunk;
        b->last = ngx_sprintf(chunk, "%xO" CRLF, size);

        tl->next = *fl;
        *fl = tl;
    }

    if (cl->buf->last_buf) {
        tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        b = tl->buf;

        b->tag = (ngx_buf_tag_t) &ngx_http_proxy_body_output_filter;
        b->temporary = 0;
        b->memory = 1;
        b->last_buf = 1;
        b->pos = (u_char *) CRLF "0" CRLF CRLF;
        b->last = b->pos + 7;

        cl->buf->last_buf = 0;

        *ll = tl;

        if (size == 0) {
            b->pos += 2;
        }

    } else if (size > 0) {
        tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        b = tl->buf;

        b->tag = (ngx_buf_tag_t) &ngx_http_proxy_body_output_filter;
        b->temporary = 0;
        b->memory = 1;
        b->pos = (u_char *) CRLF;
        b->last = b->pos + 2;

        *ll = tl;

    } else {
        *ll = NULL;
    }

out:

    rc = ngx_chain_writer(&r->upstream->writer, out);

    ngx_chain_update_chains(r->pool, &ctx->free, &ctx->busy, &out,
                            (ngx_buf_tag_t) &ngx_http_proxy_body_output_filter);

    return rc;
}


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;
        u->headers_in.connection_close = 1;

        return NGX_OK;
    }

    if (u->state && u->state->status == 0) {
        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);

    if (ctx->status.http_version < NGX_HTTP_VERSION_11) {
        u->headers_in.connection_close = 1;
    }

    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_t            *u;
    ngx_http_proxy_ctx_t           *ctx;
    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) {
                h->hash = 0;
                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_memcpy(h->key.data, r->header_name_start, h->key.len);
            h->key.data[h->key.len] = '\0';
            ngx_memcpy(h->value.data, r->header_start, h->value.len);
            h->value.data[h->value.len] = '\0';

            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) {
                rc = hh->handler(r, h, hh->offset);

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

            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";
                h->next = NULL;
            }

            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";
                h->next = NULL;
            }

            /* clear content length if response is chunked */

            u = r->upstream;

            if (u->headers_in.chunked) {
                u->headers_in.content_length_n = -1;
            }

            /*
             * set u->keepalive if response has no body; this allows to keep
             * connections alive in case of r->header_only or X-Accel-Redirect
             */

            ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

            if (u->headers_in.status_n == NGX_HTTP_NO_CONTENT
                || u->headers_in.status_n == NGX_HTTP_NOT_MODIFIED
                || ctx->head
                || (!u->headers_in.chunked
                    && u->headers_in.content_length_n == 0))
            {
                u->keepalive = !u->headers_in.connection_close;
            }

            if (u->headers_in.status_n == NGX_HTTP_SWITCHING_PROTOCOLS) {
                u->keepalive = 0;

                if (r->headers_in.upgrade) {
                    u->upgrade = 1;
                }
            }

            return NGX_OK;
        }

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

        /* rc == NGX_HTTP_PARSE_INVALID_HEADER */

        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                      "upstream sent invalid header: \"%*s\\x%02xd...\"",
                      r->header_end - r->header_name_start,
                      r->header_name_start, *r->header_end);

        return NGX_HTTP_UPSTREAM_INVALID_HEADER;
    }
}


static ngx_int_t
ngx_http_proxy_input_filter_init(void *data)
{
    ngx_http_request_t    *r = data;
    ngx_http_upstream_t   *u;
    ngx_http_proxy_ctx_t  *ctx;

    u = r->upstream;
    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

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

    ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "http proxy filter init s:%ui h:%d c:%d l:%O",
                   u->headers_in.status_n, ctx->head, u->headers_in.chunked,
                   u->headers_in.content_length_n);

    /* as per RFC2616, 4.4 Message Length */

    if (u->headers_in.status_n == NGX_HTTP_NO_CONTENT
        || u->headers_in.status_n == NGX_HTTP_NOT_MODIFIED
        || ctx->head)
    {
        /* 1xx, 204, and 304 and replies to HEAD requests */
        /* no 1xx since we don't send Expect and Upgrade */

        u->pipe->length = 0;
        u->length = 0;
        u->keepalive = !u->headers_in.connection_close;

    } else if (u->headers_in.chunked) {
        /* chunked */

        u->pipe->input_filter = ngx_http_proxy_chunked_filter;
        u->pipe->length = 3; /* "0" LF LF */

        u->input_filter = ngx_http_proxy_non_buffered_chunked_filter;
        u->length = 1;

    } else if (u->headers_in.content_length_n == 0) {
        /* empty body: special case as filter won't be called */

        u->pipe->length = 0;
        u->length = 0;
        u->keepalive = !u->headers_in.connection_close;

    } else {
        /* content length or connection close */

        u->pipe->length = u->headers_in.content_length_n;
        u->length = u->headers_in.content_length_n;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_copy_filter(ngx_event_pipe_t *p, ngx_buf_t *buf)
{
    ngx_buf_t           *b;
    ngx_chain_t         *cl;
    ngx_http_request_t  *r;

    if (buf->pos == buf->last) {
        return NGX_OK;
    }

    if (p->upstream_done) {
        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, p->log, 0,
                       "http proxy data after close");
        return NGX_OK;
    }

    if (p->length == 0) {

        ngx_log_error(NGX_LOG_WARN, p->log, 0,
                      "upstream sent more data than specified in "
                      "\"Content-Length\" header");

        r = p->input_ctx;
        r->upstream->keepalive = 0;
        p->upstream_done = 1;

        return NGX_OK;
    }

    cl = ngx_chain_get_free_buf(p->pool, &p->free);
    if (cl == NULL) {
        return NGX_ERROR;
    }

    b = cl->buf;

    ngx_memcpy(b, buf, sizeof(ngx_buf_t));
    b->shadow = buf;
    b->tag = p->tag;
    b->last_shadow = 1;
    b->recycled = 1;
    buf->shadow = b;

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0, "input buf #%d", b->num);

    if (p->in) {
        *p->last_in = cl;
    } else {
        p->in = cl;
    }
    p->last_in = &cl->next;

    if (p->length == -1) {
        return NGX_OK;
    }

    if (b->last - b->pos > p->length) {

        ngx_log_error(NGX_LOG_WARN, p->log, 0,
                      "upstream sent more data than specified in "
                      "\"Content-Length\" header");

        b->last = b->pos + p->length;
        p->upstream_done = 1;

        return NGX_OK;
    }

    p->length -= b->last - b->pos;

    if (p->length == 0) {
        r = p->input_ctx;
        r->upstream->keepalive = !r->upstream->headers_in.connection_close;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_chunked_filter(ngx_event_pipe_t *p, ngx_buf_t *buf)
{
    ngx_int_t              rc;
    ngx_buf_t             *b, **prev;
    ngx_chain_t           *cl;
    ngx_http_request_t    *r;
    ngx_http_proxy_ctx_t  *ctx;

    if (buf->pos == buf->last) {
        return NGX_OK;
    }

    r = p->input_ctx;
    ctx = ngx_http_get_module_ctx(r, ngx_http_proxy_module);

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

    if (p->upstream_done) {
        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, p->log, 0,
                       "http proxy data after close");
        return NGX_OK;
    }

    if (p->length == 0) {

        ngx_log_error(NGX_LOG_WARN, p->log, 0,
                      "upstream sent data after final chunk");

        r->upstream->keepalive = 0;
        p->upstream_done = 1;

        return NGX_OK;
    }

    b = NULL;
    prev = &buf->shadow;

    for ( ;; ) {

#if (nginx_version >= 1028000)
        rc = ngx_http_parse_chunked(r, buf, &ctx->chunked, 0);
#else
        rc = ngx_http_parse_chunked(r, buf, &ctx->chunked);
#endif

        if (rc == NGX_OK) {

            /* a chunk has been parsed successfully */

            cl = ngx_chain_get_free_buf(p->pool, &p->free);
            if (cl == NULL) {
                return NGX_ERROR;
            }

            b = cl->buf;

            ngx_memzero(b, sizeof(ngx_buf_t));

            b->pos = buf->pos;
            b->start = buf->start;
            b->end = buf->end;
            b->tag = p->tag;
            b->temporary = 1;
            b->recycled = 1;

            *prev = b;
            prev = &b->shadow;

            if (p->in) {
                *p->last_in = cl;
            } else {
                p->in = cl;
            }
            p->last_in = &cl->next;

            /* STUB */ b->num = buf->num;

            ngx_log_debug2(NGX_LOG_DEBUG_EVENT, p->log, 0,
                           "input buf #%d %p", b->num, b->pos);

            if (buf->last - buf->pos >= ctx->chunked.size) {

                buf->pos += (size_t) ctx->chunked.size;
                b->last = buf->pos;
                ctx->chunked.size = 0;

                continue;
            }

            ctx->chunked.size -= buf->last - buf->pos;
            buf->pos = buf->last;
            b->last = buf->last;

            continue;
        }

        if (rc == NGX_DONE) {

            /* a whole response has been parsed successfully */

            p->length = 0;
            r->upstream->keepalive = !r->upstream->headers_in.connection_close;

            if (buf->pos != buf->last) {
                ngx_log_error(NGX_LOG_WARN, p->log, 0,
                              "upstream sent data after final chunk");
                r->upstream->keepalive = 0;
            }

            break;
        }

        if (rc == NGX_AGAIN) {

            /* set p->length, minimal amount of data we want to see */

            p->length = ctx->chunked.length;

            break;
        }

        /* invalid response */

        ngx_log_error(NGX_LOG_ERR, p->log, 0,
                      "upstream sent invalid chunked response");

        return NGX_ERROR;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, p->log, 0,
                   "http proxy chunked state %ui, length %O",
                   ctx->chunked.state, p->length);

    if (b) {
        b->shadow = buf;
        b->last_shadow = 1;

        ngx_log_debug2(NGX_LOG_DEBUG_EVENT, p->log, 0,
                       "input buf %p %z", b->pos, b->last - b->pos);

        return NGX_OK;
    }

    /* there is no data record in the buf, add it to free chain */

    if (ngx_event_pipe_add_free_buf(p, buf) != NGX_OK) {
        return NGX_ERROR;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_non_buffered_copy_filter(void *data, ssize_t bytes)
{
    ngx_http_request_t   *r = data;

    ngx_buf_t            *b;
    ngx_chain_t          *cl, **ll;
    ngx_http_upstream_t  *u;

    u = r->upstream;

    if (u->length == 0) {
        ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                      "upstream sent more data than specified in "
                      "\"Content-Length\" header");
        u->keepalive = 0;
        return NGX_OK;
    }

    for (cl = u->out_bufs, ll = &u->out_bufs; cl; cl = cl->next) {
        ll = &cl->next;
    }

    cl = ngx_chain_get_free_buf(r->pool, &u->free_bufs);
    if (cl == NULL) {
        return NGX_ERROR;
    }

    *ll = cl;

    cl->buf->flush = 1;
    cl->buf->memory = 1;

    b = &u->buffer;

    cl->buf->pos = b->last;
    b->last += bytes;
    cl->buf->last = b->last;
    cl->buf->tag = u->output.tag;

    if (u->length == -1) {
        return NGX_OK;
    }

    if (bytes > u->length) {

        ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                      "upstream sent more data than specified in "
                      "\"Content-Length\" header");

        cl->buf->last = cl->buf->pos + u->length;
        u->length = 0;

        return NGX_OK;
    }

    u->length -= bytes;

    if (u->length == 0) {
        u->keepalive = !u->headers_in.connection_close;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_non_buffered_chunked_filter(void *data, ssize_t bytes)
{
    ngx_http_request_t   *r = data;

    ngx_int_t              rc;
    ngx_buf_t             *b, *buf;
    ngx_chain_t           *cl, **ll;
    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;
    buf = &u->buffer;

    buf->pos = buf->last;
    buf->last += bytes;

    for (cl = u->out_bufs, ll = &u->out_bufs; cl; cl = cl->next) {
        ll = &cl->next;
    }

    for ( ;; ) {

#if (nginx_version >= 1028000)
        rc = ngx_http_parse_chunked(r, buf, &ctx->chunked, 0);
#else
        rc = ngx_http_parse_chunked(r, buf, &ctx->chunked);
#endif

        if (rc == NGX_OK) {

            /* a chunk has been parsed successfully */

            cl = ngx_chain_get_free_buf(r->pool, &u->free_bufs);
            if (cl == NULL) {
                return NGX_ERROR;
            }

            *ll = cl;
            ll = &cl->next;

            b = cl->buf;

            b->flush = 1;
            b->memory = 1;

            b->pos = buf->pos;
            b->tag = u->output.tag;

            if (buf->last - buf->pos >= ctx->chunked.size) {
                buf->pos += (size_t) ctx->chunked.size;
                b->last = buf->pos;
                ctx->chunked.size = 0;

            } else {
                ctx->chunked.size -= buf->last - buf->pos;
                buf->pos = buf->last;
                b->last = buf->last;
            }

            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "http proxy out buf %p %z",
                           b->pos, b->last - b->pos);

            continue;
        }

        if (rc == NGX_DONE) {

            /* a whole response has been parsed successfully */

            u->keepalive = !u->headers_in.connection_close;
            u->length = 0;

            if (buf->pos != buf->last) {
                ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                              "upstream sent data after final chunk");
                u->keepalive = 0;
            }

            break;
        }

        if (rc == NGX_AGAIN) {
            break;
        }

        /* invalid response */

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

        return NGX_ERROR;
    }

    return NGX_OK;
}


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_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 || ctx->internal_body_length < 0) {
        v->not_found = 1;
        return NGX_OK;
    }

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

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

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

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

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_internal_chunked_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 || !ctx->internal_chunked) {
        v->not_found = 1;
        return NGX_OK;
    }

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

    v->data = (u_char *) "chunked";
    v->len = sizeof("chunked") - 1;

    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)
{
    size_t                      len;
    ngx_int_t                   rc;
    ngx_uint_t                  i;
    ngx_http_proxy_rewrite_t   *pr;
    ngx_http_proxy_loc_conf_t  *plcf;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    pr = plcf->redirects->elts;

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

    len = h->value.len - prefix;

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

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

    return NGX_DECLINED;
}


static ngx_int_t
ngx_http_proxy_rewrite_cookie(ngx_http_request_t *r, ngx_table_elt_t *h)
{
    u_char                     *p;
    size_t                      len;
    ngx_int_t                   rc, rv;
    ngx_str_t                  *key, *value;
    ngx_uint_t                  i;
    ngx_array_t                 attrs;
    ngx_keyval_t               *attr;
    ngx_http_proxy_loc_conf_t  *plcf;

    if (ngx_array_init(&attrs, r->pool, 2, sizeof(ngx_keyval_t)) != NGX_OK) {
        return NGX_ERROR;
    }

    if (ngx_http_proxy_parse_cookie(&h->value, &attrs) != NGX_OK) {
        return NGX_ERROR;
    }

    attr = attrs.elts;

    if (attr[0].value.data == NULL) {
        return NGX_DECLINED;
    }

    rv = NGX_DECLINED;

    plcf = ngx_http_get_module_loc_conf(r, ngx_http_proxy_module);

    for (i = 1; i < attrs.nelts; i++) {

        key = &attr[i].key;
        value = &attr[i].value;

        if (plcf->cookie_domains && key->len == 6
            && ngx_strncasecmp(key->data, (u_char *) "domain", 6) == 0
            && value->data)
        {
            rc = ngx_http_proxy_rewrite_cookie_value(r, value,
                                                     plcf->cookie_domains);
            if (rc == NGX_ERROR) {
                return NGX_ERROR;
            }

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

        if (plcf->cookie_paths && key->len == 4
            && ngx_strncasecmp(key->data, (u_char *) "path", 4) == 0
            && value->data)
        {
            rc = ngx_http_proxy_rewrite_cookie_value(r, value,
                                                     plcf->cookie_paths);
            if (rc == NGX_ERROR) {
                return NGX_ERROR;
            }

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

    if (plcf->cookie_flags) {
        rc = ngx_http_proxy_rewrite_cookie_flags(r, &attrs,
                                                 plcf->cookie_flags);
        if (rc == NGX_ERROR) {
            return NGX_ERROR;
        }

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

        attr = attrs.elts;
    }

    if (rv != NGX_OK) {
        return rv;
    }

    len = 0;

    for (i = 0; i < attrs.nelts; i++) {

        if (attr[i].key.data == NULL) {
            continue;
        }

        if (i > 0) {
            len += 2;
        }

        len += attr[i].key.len;

        if (attr[i].value.data) {
            len += 1 + attr[i].value.len;
        }
    }

    p = ngx_pnalloc(r->pool, len + 1);
    if (p == NULL) {
        return NGX_ERROR;
    }

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

    for (i = 0; i < attrs.nelts; i++) {

        if (attr[i].key.data == NULL) {
            continue;
        }

        if (i > 0) {
            *p++ = ';';
            *p++ = ' ';
        }

        p = ngx_cpymem(p, attr[i].key.data, attr[i].key.len);

        if (attr[i].value.data) {
            *p++ = '=';
            p = ngx_cpymem(p, attr[i].value.data, attr[i].value.len);
        }
    }

    *p = '\0';

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_parse_cookie(ngx_str_t *value, ngx_array_t *attrs)
{
    u_char        *start, *end, *p, *last;
    ngx_str_t      name, val;
    ngx_keyval_t  *attr;

    start = value->data;
    end = value->data + value->len;

    for ( ;; ) {

        last = (u_char *) ngx_strchr(start, ';');

        if (last == NULL) {
            last = end;
        }

        while (start < last && *start == ' ') { start++; }

        for (p = start; p < last && *p != '='; p++) { /* void */ }

        name.data = start;
        name.len = p - start;

        while (name.len && name.data[name.len - 1] == ' ') {
            name.len--;
        }

        if (p < last) {

            p++;

            while (p < last && *p == ' ') { p++; }

            val.data = p;
            val.len = last - val.data;

            while (val.len && val.data[val.len - 1] == ' ') {
                val.len--;
            }

        } else {
            ngx_str_null(&val);
        }

        attr = ngx_array_push(attrs);
        if (attr == NULL) {
            return NGX_ERROR;
        }

        attr->key = name;
        attr->value = val;

        if (last == end) {
            break;
        }

        start = last + 1;
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_rewrite_cookie_value(ngx_http_request_t *r, ngx_str_t *value,
    ngx_array_t *rewrites)
{
    ngx_int_t                  rc;
    ngx_uint_t                 i;
    ngx_http_proxy_rewrite_t  *pr;

    pr = rewrites->elts;

    for (i = 0; i < rewrites->nelts; i++) {
        rc = pr[i].handler(r, value, 0, value->len, &pr[i]);

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

    return NGX_DECLINED;
}


static ngx_int_t
ngx_http_proxy_rewrite_cookie_flags(ngx_http_request_t *r, ngx_array_t *attrs,
    ngx_array_t *flags)
{
    ngx_str_t                       pattern, value;
#if (NGX_PCRE)
    ngx_int_t                       rc;
#endif
    ngx_uint_t                      i, m, f, nelts;
    ngx_keyval_t                   *attr;
    ngx_conf_bitmask_t             *mask;
    ngx_http_complex_value_t       *flags_values;
    ngx_http_proxy_cookie_flags_t  *pcf;

    attr = attrs->elts;
    pcf = flags->elts;

    for (i = 0; i < flags->nelts; i++) {

#if (NGX_PCRE)
        if (pcf[i].regex) {
            rc = ngx_http_regex_exec(r, pcf[i].cookie.regex, &attr[0].key);

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

            if (rc == NGX_OK) {
                break;
            }

            /* NGX_DECLINED */

            continue;
        }
#endif

        if (ngx_http_complex_value(r, &pcf[i].cookie.complex, &pattern)
            != NGX_OK)
        {
            return NGX_ERROR;
        }

        if (pattern.len == attr[0].key.len
            && ngx_strncasecmp(attr[0].key.data, pattern.data, pattern.len)
               == 0)
        {
            break;
        }
    }

    if (i == flags->nelts) {
        return NGX_DECLINED;
    }

    nelts = pcf[i].flags_values.nelts;
    flags_values = pcf[i].flags_values.elts;

    mask = ngx_http_proxy_cookie_flags_masks;
    f = 0;

    for (i = 0; i < nelts; i++) {

        if (ngx_http_complex_value(r, &flags_values[i], &value) != NGX_OK) {
            return NGX_ERROR;
        }

        if (value.len == 0) {
            continue;
        }

        for (m = 0; mask[m].name.len != 0; m++) {

            if (mask[m].name.len != value.len
                || ngx_strncasecmp(mask[m].name.data, value.data, value.len)
                   != 0)
            {
                continue;
            }

            f |= mask[m].mask;

            break;
        }

        if (mask[m].name.len == 0) {
            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                           "invalid proxy_cookie_flags flag \"%V\"", &value);
        }
    }

    if (f == 0) {
        return NGX_DECLINED;
    }

    return ngx_http_proxy_edit_cookie_flags(r, attrs, f);
}


static ngx_int_t
ngx_http_proxy_edit_cookie_flags(ngx_http_request_t *r, ngx_array_t *attrs,
    ngx_uint_t flags)
{
    ngx_str_t     *key, *value;
    ngx_uint_t     i;
    ngx_keyval_t  *attr;

    attr = attrs->elts;

    for (i = 1; i < attrs->nelts; i++) {
        key = &attr[i].key;

        if (key->len == 6
            && ngx_strncasecmp(key->data, (u_char *) "secure", 6) == 0)
        {
            if (flags & NGX_HTTP_PROXY_COOKIE_SECURE_ON) {
                flags &= ~NGX_HTTP_PROXY_COOKIE_SECURE_ON;

            } else if (flags & NGX_HTTP_PROXY_COOKIE_SECURE_OFF) {
                key->data = NULL;
            }

            continue;
        }

        if (key->len == 8
            && ngx_strncasecmp(key->data, (u_char *) "httponly", 8) == 0)
        {
            if (flags & NGX_HTTP_PROXY_COOKIE_HTTPONLY_ON) {
                flags &= ~NGX_HTTP_PROXY_COOKIE_HTTPONLY_ON;

            } else if (flags & NGX_HTTP_PROXY_COOKIE_HTTPONLY_OFF) {
                key->data = NULL;
            }

            continue;
        }

        if (key->len == 8
            && ngx_strncasecmp(key->data, (u_char *) "samesite", 8) == 0)
        {
            value = &attr[i].value;

            if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT) {
                flags &= ~NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT;

                if (value->len != 6
                    || ngx_strncasecmp(value->data, (u_char *) "strict", 6)
                       != 0)
                {
                    ngx_str_set(key, "SameSite");
                    ngx_str_set(value, "Strict");
                }

            } else if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX) {
                flags &= ~NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX;

                if (value->len != 3
                    || ngx_strncasecmp(value->data, (u_char *) "lax", 3) != 0)
                {
                    ngx_str_set(key, "SameSite");
                    ngx_str_set(value, "Lax");
                }

            } else if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_NONE) {
                flags &= ~NGX_HTTP_PROXY_COOKIE_SAMESITE_NONE;

                if (value->len != 4
                    || ngx_strncasecmp(value->data, (u_char *) "none", 4) != 0)
                {
                    ngx_str_set(key, "SameSite");
                    ngx_str_set(value, "None");
                }

            } else if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_OFF) {
                key->data = NULL;
            }

            continue;
        }
    }

    if (flags & NGX_HTTP_PROXY_COOKIE_SECURE_ON) {
        attr = ngx_array_push(attrs);
        if (attr == NULL) {
            return NGX_ERROR;
        }

        ngx_str_set(&attr->key, "Secure");
        ngx_str_null(&attr->value);
    }

    if (flags & NGX_HTTP_PROXY_COOKIE_HTTPONLY_ON) {
        attr = ngx_array_push(attrs);
        if (attr == NULL) {
            return NGX_ERROR;
        }

        ngx_str_set(&attr->key, "HttpOnly");
        ngx_str_null(&attr->value);
    }

    if (flags & (NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT
                 |NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX
                 |NGX_HTTP_PROXY_COOKIE_SAMESITE_NONE))
    {
        attr = ngx_array_push(attrs);
        if (attr == NULL) {
            return NGX_ERROR;
        }

        ngx_str_set(&attr->key, "SameSite");

        if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_STRICT) {
            ngx_str_set(&attr->value, "Strict");

        } else if (flags & NGX_HTTP_PROXY_COOKIE_SAMESITE_LAX) {
            ngx_str_set(&attr->value, "Lax");

        } else {
            ngx_str_set(&attr->value, "None");
        }
    }

    return NGX_OK;
}


static ngx_int_t
ngx_http_proxy_rewrite_complex_handler(ngx_http_request_t *r, ngx_str_t *value,
    size_t prefix, size_t len, ngx_http_proxy_rewrite_t *pr)
{
    ngx_str_t  pattern, replacement;

    if (ngx_http_complex_value(r, &pr->pattern.complex, &pattern) != NGX_OK) {
        return NGX_ERROR;
    }

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

    if (ngx_http_complex_value(r, &pr->replacement, &replacement) != NGX_OK) {
        return NGX_ERROR;
    }

    return ngx_http_proxy_rewrite(r, value, prefix, pattern.len, &replacement);
}


static ngx_int_t
ngx_http_proxy_rewrite_domain_handler(ngx_http_request_t *r, ngx_str_t *value,
    size_t prefix, size_t len, ngx_http_proxy_rewrite_t *pr)
{
    u_char     *p;
    ngx_str_t   pattern, replacement;

    if (ngx_http_complex_value(r, &pr->pattern.complex, &pattern) != NGX_OK) {
        return NGX_ERROR;
    }

    p = value->data + prefix;

    if (len && p[0] == '.') {
        p++;
        prefix++;
        len--;
    }

    if (pattern.len != len || ngx_rstrncasecmp(pattern.data, p, len) != 0) {
        return NGX_DECLINED;
    }

    if (ngx_http_complex_value(r, &pr->replacement, &replacement) != NGX_OK) {
        return NGX_ERROR;
    }

    return ngx_http_proxy_rewrite(r, value, prefix, len, &replacement);
}


static ngx_int_t
ngx_http_proxy_rewrite_regex_handler(ngx_http_request_t *r, ngx_str_t *value,
    size_t prefix, size_t len, ngx_http_proxy_rewrite_t *pr)
{
    ngx_str_t  pattern, replacement;

    pattern.len = len;
    pattern.data = value->data + prefix;

    if (ngx_http_regex_exec(r, pr->pattern.regex, &pattern) != NGX_OK) {
        return NGX_DECLINED;
    }

    if (ngx_http_complex_value(r, &pr->replacement, &replacement) != NGX_OK) {
        return NGX_ERROR;
    }

    return ngx_http_proxy_rewrite(r, value, prefix, len, &replacement);
}


static ngx_int_t
ngx_http_proxy_rewrite(ngx_http_request_t *r, ngx_str_t *value, size_t prefix,
    size_t len, ngx_str_t *replacement)
{
    u_char  *p, *data;
    size_t   new_len;

    if (len == value->len) {
        *value = *replacement;
        return NGX_OK;
    }

    new_len = replacement->len + value->len - len;

    if (replacement->len > len) {

        data = ngx_pnalloc(r->pool, new_len + 1);
        if (data == NULL) {
            return NGX_ERROR;
        }

        p = ngx_copy(data, value->data, prefix);
        p = ngx_copy(p, replacement->data, replacement->len);

        ngx_memcpy(p, value->data + prefix + len,
                   value->len - len - prefix + 1);

        value->data = data;

    } else {
        p = ngx_copy(value->data + prefix, replacement->data, replacement->len);

        ngx_memmove(p, value->data + prefix + len,
                    value->len - len - prefix + 1);
    }

    value->len = new_len;

    return NGX_OK;
}


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;
}


#endif /* _NGX_HTTP_PROXY_MODULE_H_INCLUDED_ */