/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/* Utility routines for Apache proxy */
#include "mod_proxy.h"
#include "http_main.h"
#include "ap_md5.h"
#include "multithread.h"
#include "http_log.h"
#include "util_uri.h"
#include "util_date.h"          /* get ap_checkmask() decl. */

static int proxy_match_ipaddr(struct dirconn_entry *This, request_rec *r);
static int proxy_match_domainname(struct dirconn_entry *This, request_rec *r);
static int proxy_match_hostname(struct dirconn_entry *This, request_rec *r);
static int proxy_match_word(struct dirconn_entry *This, request_rec *r);
static struct per_thread_data *get_per_thread_data(void);
/* already called in the knowledge that the characters are hex digits */
int ap_proxy_hex2c(const char *x)
{
    int i;
#ifndef CHARSET_EBCDIC
    int ch;

    ch = x[0];
    if (ap_isdigit(ch))
        i = ch - '0';
    else if (ap_isupper(ch))
        i = ch - ('A' - 10);
    else
        i = ch - ('a' - 10);
    i <<= 4;

    ch = x[1];
    if (ap_isdigit(ch))
        i += ch - '0';
    else if (ap_isupper(ch))
        i += ch - ('A' - 10);
    else
        i += ch - ('a' - 10);
    return i;
#else                           /* CHARSET_EBCDIC */
    return (1 == sscanf(x, "%2x", &i)) ? os_toebcdic[i & 0xFF] : 0;
#endif                          /* CHARSET_EBCDIC */
}

void ap_proxy_c2hex(int ch, char *x)
{
#ifndef CHARSET_EBCDIC
    int i;

    x[0] = '%';
    i = (ch & 0xF0) >> 4;
    if (i >= 10)
        x[1] = ('A' - 10) + i;
    else
        x[1] = '0' + i;

    i = ch & 0x0F;
    if (i >= 10)
        x[2] = ('A' - 10) + i;
    else
        x[2] = '0' + i;
#else                           /* CHARSET_EBCDIC */
    static const char ntoa[] = {"0123456789ABCDEF"};
    ch = os_toascii[ch & 0xFF];
    x[0] = '%';
    x[1] = ntoa[(ch >> 4) & 0x0F];
    x[2] = ntoa[ch & 0x0F];
    x[3] = '\0';
#endif                          /* CHARSET_EBCDIC */
}

/*
 * canonicalise a URL-encoded string
 */

/*
 * Convert a URL-encoded string to canonical form.
 * It decodes characters which need not be encoded,
 * and encodes those which must be encoded, and does not touch
 * those which must not be touched.
 */
char *ap_proxy_canonenc(pool *p, const char *x, int len, enum enctype t,
                             enum proxyreqtype isenc)
{
    int i, j, ch;
    char *y;
    const char *allowed;        /* characters which should not be encoded */
    const char *reserved;       /* characters which much not be en/de-coded */

/* N.B. in addition to :@&=, this allows ';' in an http path
 * and '?' in an ftp path -- this may be revised
 *
 * Also, it makes a '+' character in a search string reserved, as
 * it may be form-encoded. (Although RFC 1738 doesn't allow this -
 * it only permits ; / ? : @ = & as reserved chars.)
 */
    if (t == enc_path)
        allowed = "$-_.+!*'(),;:@&=";
    else if (t == enc_search)
        allowed = "$-_.!*'(),;:@&=";
    else if (t == enc_user)
        allowed = "$-_.+!*'(),;@&=";
    else if (t == enc_fpath)
        allowed = "$-_.+!*'(),?:@&=";
    else                        /* if (t == enc_parm) */
        allowed = "$-_.+!*'(),?/:@&=";

    if (t == enc_path)
        reserved = "/";
    else if (t == enc_search)
        reserved = "+";
    else
        reserved = "";

    y = ap_palloc(p, 3 * len + 1);

    for (i = 0, j = 0; i < len; i++, j++) {
/* always handle '/' first */
        ch = x[i];
        if (strchr(reserved, ch)) {
            y[j] = ch;
            continue;
        }
/* decode it if not already done */
        if (isenc != NOT_PROXY && ch == '%') {
            if (!ap_isxdigit(x[i + 1]) || !ap_isxdigit(x[i + 2]))
                return NULL;
            ch = ap_proxy_hex2c(&x[i + 1]);
            i += 2;
            if (ch != 0 && strchr(reserved, ch)) {      /* keep it encoded */
                ap_proxy_c2hex(ch, &y[j]);
                j += 2;
                continue;
            }
        }
/* recode it, if necessary */
        if (!ap_isalnum(ch) && !strchr(allowed, ch)) {
            ap_proxy_c2hex(ch, &y[j]);
            j += 2;
        }
        else
            y[j] = ch;
    }
    y[j] = '\0';
    return y;
}

/*
 * Parses network-location.
 *    urlp           on input the URL; on output the path, after the leading /
 *    user           NULL if no user/password permitted
 *    password       holder for password
 *    host           holder for host
 *    port           port number; only set if one is supplied.
 *
 * Returns an error string.
 */
char *
     ap_proxy_canon_netloc(pool *p, char **const urlp, char **userp,
                                char **passwordp, char **hostp, int *port)
{
    int i;
    char *strp, *host, *url = *urlp;
    char *user = NULL, *password = NULL;

    if (url[0] != '/' || url[1] != '/')
        return "Malformed URL";
    host = url + 2;
    url = strchr(host, '/');
    if (url == NULL)
        url = "";
    else
        *(url++) = '\0';        /* skip seperating '/' */

    /* find _last_ '@' since it might occur in user/password part */
    strp = strrchr(host, '@');

    if (strp != NULL) {
        *strp = '\0';
        user = host;
        host = strp + 1;

/* find password */
        strp = strchr(user, ':');
        if (strp != NULL) {
            *strp = '\0';
            password = ap_proxy_canonenc(p, strp + 1, strlen(strp + 1), enc_user, STD_PROXY);
            if (password == NULL)
                return "Bad %-escape in URL (password)";
        }

        user = ap_proxy_canonenc(p, user, strlen(user), enc_user, STD_PROXY);
        if (user == NULL)
            return "Bad %-escape in URL (username)";
    }
    if (userp != NULL) {
        *userp = user;
    }
    if (passwordp != NULL) {
        *passwordp = password;
    }

    strp = strrchr(host, ':');
    if (strp != NULL) {
        *(strp++) = '\0';

        for (i = 0; strp[i] != '\0'; i++)
            if (!ap_isdigit(strp[i]))
                break;

        /* if (i == 0) the no port was given; keep default */
        if (strp[i] != '\0') {
            return "Bad port number in URL";
        }
        else if (i > 0) {
            *port = atoi(strp);
            if (*port > 65535)
                return "Port number in URL > 65535";
        }
    }
    ap_str_tolower(host);       /* DNS names are case-insensitive */
    if (*host == '\0')
        return "Missing host in URL";
/* check hostname syntax */
    for (i = 0; host[i] != '\0'; i++)
        if (!ap_isdigit(host[i]) && host[i] != '.')
            break;
    /* must be an IP address */
#if defined(WIN32) || defined(NETWARE) || defined(TPF) || defined(BEOS)
    if (host[i] == '\0' && (inet_addr(host) == -1))
#else
    if (host[i] == '\0' && (ap_inet_addr(host) == -1 || inet_network(host) == -1))
#endif
    {
        return "Bad IP address in URL";
    }

/*    if (strchr(host,'.') == NULL && domain != NULL)
   host = pstrcat(p, host, domain, NULL);
 */
    *urlp = url;
    *hostp = host;

    return NULL;
}

static const char *const lwday[7] =
{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

/*
 * If the date is a valid RFC 850 date or asctime() date, then it
 * is converted to the RFC 1123 format, otherwise it is not modified.
 * This routine is not very fast at doing conversions, as it uses
 * sscanf and sprintf. However, if the date is already correctly
 * formatted, then it exits very quickly.
 */
const char *
     ap_proxy_date_canon(pool *p, const char *x)
{
    int wk, mday, year, hour, min, sec, mon;
    char *q, month[4], zone[4], week[4];

    q = strchr(x, ',');
    /* check for RFC 850 date */
    if (q != NULL && q - x > 3 && q[1] == ' ') {
        *q = '\0';
        for (wk = 0; wk < 7; wk++)
            if (strcmp(x, lwday[wk]) == 0)
                break;
        *q = ',';
        if (wk == 7)
            return x;           /* not a valid date */
        if (q[4] != '-' || q[8] != '-' || q[11] != ' ' || q[14] != ':' ||
            q[17] != ':' || strcmp(&q[20], " GMT") != 0)
            return x;
        if (sscanf(q + 2, "%u-%3s-%u %u:%u:%u %3s", &mday, month, &year,
                   &hour, &min, &sec, zone) != 7)
            return x;
        if (year < 70)
            year += 2000;
        else
            year += 1900;
    }
    else {
/* check for acstime() date */
        if (x[3] != ' ' || x[7] != ' ' || x[10] != ' ' || x[13] != ':' ||
            x[16] != ':' || x[19] != ' ' || x[24] != '\0')
            return x;
        if (sscanf(x, "%3s %3s %u %u:%u:%u %u", week, month, &mday, &hour,
                   &min, &sec, &year) != 7)
            return x;
        for (wk = 0; wk < 7; wk++)
            if (strcmp(week, ap_day_snames[wk]) == 0)
                break;
        if (wk == 7)
            return x;
    }

/* check date */
    for (mon = 0; mon < 12; mon++)
        if (strcmp(month, ap_month_snames[mon]) == 0)
            break;
    if (mon == 12)
        return x;

    q = ap_palloc(p, 30);
    ap_snprintf(q, 30, "%s, %.2d %s %d %.2d:%.2d:%.2d GMT", ap_day_snames[wk], mday,
                ap_month_snames[mon], year, hour, min, sec);
    return q;
}


/*
 * Reads headers from a buffer and returns an array of headers.
 * Returns NULL on file error
 * This routine tries to deal with too long lines and continuation lines.
 *
 * Note: Currently the headers are passed through unmerged. This has to be
 * done so that headers which react badly to merging (such as Set-Cookie
 * headers, which contain commas within the date field) do not get stuffed
 * up.
 */
table *ap_proxy_read_headers(request_rec *r, char *buffer, int size, BUFF *f)
{
    table *resp_hdrs;
    int len;
    char *value, *end;
    char field[MAX_STRING_LEN];

    resp_hdrs = ap_make_table(r->pool, 20);

    /*
     * Read header lines until we get the empty separator line, a read error,
     * the connection closes (EOF), or we timeout.
     */
    while ((len = ap_getline(buffer, size, f, 1)) > 0) {

        if (!(value = strchr(buffer, ':'))) {   /* Find the colon separator */

            /*
             * Buggy MS IIS servers sometimes return invalid headers (an
             * extra "HTTP/1.0 200, OK" line sprinkled in between the usual
             * MIME headers). Try to deal with it in a sensible way, but log
             * the fact. XXX: The mask check is buggy if we ever see an
             * HTTP/1.10
             */

            if (!ap_checkmask(buffer, "HTTP/#.# ###*")) {
                /* Nope, it wasn't even an extra HTTP header. Give up. */
                return NULL;
            }

            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_NOERRNO, r->server,
                         "proxy: Ignoring duplicate HTTP status line "
                         "returned by buggy server %s (%s)", r->uri, r->method);
            continue;
        }

        *value = '\0';
        ++value;
        /*
         * XXX: RFC2068 defines only SP and HT as whitespace, this test is
         * wrong... and so are many others probably.
         */
        while (ap_isspace(*value))
            ++value;            /* Skip to start of value   */

        /* should strip trailing whitespace as well */
        for (end = &value[strlen(value) - 1]; end > value && ap_isspace(*end); --end)
            *end = '\0';

        /* make sure we add so as not to destroy duplicated headers */
        ap_table_add(resp_hdrs, buffer, value);

        /* the header was too long; at the least we should skip extra data */
        if (len >= size - 1) {
            while ((len = ap_getline(field, MAX_STRING_LEN, f, 1))
                   >= MAX_STRING_LEN - 1) {
                /* soak up the extra data */
            }
            if (len == 0)       /* time to exit the larger loop as well */
                break;
        }
    }
    return resp_hdrs;
}

/* read data from (socket BUFF*) f, write it to:
 * - c->fp, if it is open
 * - r->connection->client, if nowrite == 0
 */

long int ap_proxy_send_fb(BUFF *f, request_rec *r, cache_req *c, off_t len, int nowrite, int chunked, size_t recv_buffer_size)
{
    int ok, end_of_chunk;
    char *buf;
    size_t buf_size;
    long remaining = 0;
    long total_bytes_rcvd;
    register int n = 0, o, w;
    conn_rec *con = r->connection;
    int alternate_timeouts = 1; /* 1 if we alternate between soft & hard
                                 * timeouts */

    /* allocate a buffer to store the bytes in */
    /*
     * make sure it is at least IOBUFSIZE, as recv_buffer_size may be zero
     * for system default
     */
    buf_size = MAX(recv_buffer_size, IOBUFSIZE);
    buf = ap_palloc(r->pool, buf_size);

    total_bytes_rcvd = 0;
    if (c != NULL)
        c->written = 0;

#ifdef CHARSET_EBCDIC
    /* The cache copy is ASCII, not EBCDIC, even for text/html) */
    ap_bsetflag(f, B_ASCII2EBCDIC | B_EBCDIC2ASCII, 0);
    ap_bsetflag(con->client, B_ASCII2EBCDIC | B_EBCDIC2ASCII, 0);
#endif

    /*
     * Since we are reading from one buffer and writing to another, it is
     * unsafe to do a soft_timeout here, at least until the proxy has its own
     * timeout handler which can set both buffers to EOUT.
     */

    ap_kill_timeout(r);

#if defined(WIN32) || defined(TPF) || defined(NETWARE)
    /* works fine under win32, so leave it */
    ap_hard_timeout("proxy send body", r);
    alternate_timeouts = 0;
#else
    /*
     * CHECKME! Since hard_timeout won't work in unix on sends with partial
     * cache completion, we have to alternate between hard_timeout for reads,
     * and soft_timeout for send.  This is because we need to get a return
     * from ap_bwrite to be able to continue caching. BUT, if we *can't*
     * continue anyway, just use hard_timeout. (Also, if no cache file is
     * written, use hard timeouts)
     */

    if (c == NULL || c->len <= 0 || c->cache_completion == 1.0) {
        ap_hard_timeout("proxy send body", r);
        alternate_timeouts = 0;
    }
#endif

    /*
     * Loop and ap_bread() while we can successfully read and write, or
     * (after the client aborted) while we can successfully read and finish
     * the configured cache_completion.
     */
    for (end_of_chunk = ok = 1; ok;) {
        if (alternate_timeouts)
            ap_hard_timeout("proxy recv body from upstream server", r);


        /* read a chunked block */
        if (chunked) {
            long chunk_start = 0;
            n = 0;

            /* start of a new chunk */
            if (end_of_chunk) {
                end_of_chunk = 0;
                /* get the chunk size from the stream */
                chunk_start = ap_getline(buf, buf_size, f, 0);
                if ((chunk_start <= 0) || ((size_t)chunk_start + 1 >= buf_size) || !ap_isxdigit(*buf)) {
                    n = -1;
                }
                /* parse the chunk size */
                else {
                    remaining = ap_get_chunk_size(buf);
                    if (remaining == 0) { /* Last chunk indicated, get footers */
                        /* as we are a proxy, we discard the footers, as the headers
                         * have already been sent at this point.
                         */
                        if (NULL == ap_proxy_read_headers(r, buf, buf_size, f)) {
                            n = -1;
                        }
                    }
                    else if (remaining < 0) {
                        n = -1;
                        ap_log_rerror(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, r,
                                      "proxy: remote protocol error, invalid chunk size");

                    }
                }
            }

            /* read the chunk */
            if (remaining > 0) {
                n = ap_bread(f, buf, MIN((int)buf_size, (int)remaining));
                if (n > -1) {
                    remaining -= n;
                    end_of_chunk = (remaining == 0);
                }
            }

            /* soak up trailing CRLF */
            if (end_of_chunk) {
                int ch; /* int because it may hold an EOF */
                /*
                 * For EBCDIC, the proxy has configured the BUFF layer to
                 * transparently pass the ascii characters thru (also writing
                 * an ASCII copy to the cache, where appropriate).
                 * Therefore, we see here an ASCII-CRLF (\015\012),
                 * not an EBCDIC-CRLF (\r\n).
                 */
                if ((ch = ap_bgetc(f)) == EOF) {
                    /* Protocol error: EOF detected within chunk */
                    n = -1;
                    ap_log_rerror(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, r,
                                  "proxy: remote protocol error, eof while reading chunked from proxy");
                }
                else
                {
                    if (ch == '\015') { /* _ASCII_ CR */
                        ch = ap_bgetc(f);
                    }
                    if (ch != '\012') {
                        n = -1;
                    }
                }
            }
        }

        /* otherwise read block normally */
        else {
            if (-1 == len) {
                n = ap_bread(f, buf, buf_size);
            }
            else {
                n = ap_bread(f, buf, MIN((int)buf_size,
                                         (int)(len - total_bytes_rcvd)));
            }
        }


        if (alternate_timeouts)
            ap_kill_timeout(r);
        else
            ap_reset_timeout(r);

        if (n == -1) {          /* input error */
            if (c != NULL) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                              "proxy: error reading from %s", c->url);
                c = ap_proxy_cache_error(c);
            }
            break;
        }
        if (n == 0)
            break;              /* EOF */
        o = 0;
        total_bytes_rcvd += n;

        /* if we've received everything... */
        /*
         * in the case of slow frontends and expensive backends, we want to
         * avoid leaving a backend connection hanging while the frontend
         * takes it's time to absorb the bytes. so: if we just read the last
         * block, we close the backend connection now instead of later - it's
         * no longer needed.
         */
        if (total_bytes_rcvd == len) {
            ap_bclose(f);
            f = NULL;
        }

        /* Write to cache first. */
        /*
         * @@@ XXX FIXME: Assuming that writing the cache file won't time
         * out?!!?
         */
        if (c != NULL && c->fp != NULL) {
            if (ap_bwrite(c->fp, &buf[0], n) != n) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                              "proxy: error writing to %s", c->tempfile);
                c = ap_proxy_cache_error(c);
            }
            else {
                c->written += n;
            }
        }

        /* Write the block to the client, detect aborted transfers */
        while (!nowrite && !con->aborted && n > 0) {
            if (alternate_timeouts)
                ap_soft_timeout("proxy send body", r);

            w = ap_bwrite(con->client, &buf[o], n);

            if (alternate_timeouts)
                ap_kill_timeout(r);
            else
                ap_reset_timeout(r);

            if (w <= 0) {
                if (c != NULL) {
                    /*
                     * when a send failure occurs, we need to decide whether
                     * to continue loading and caching the document, or to
                     * abort the whole thing
                     */
                    ok = (c->len > 0) &&
                        (c->cache_completion > 0) &&
                        (c->len * c->cache_completion < total_bytes_rcvd);

                    if (!ok) {
                        if (c->fp != NULL) {
                            ap_pclosef(c->req->pool, ap_bfileno(c->fp, B_WR));
                            c->fp = NULL;
                        }
                        unlink(c->tempfile);
                        c = NULL;
                    }
                }
                con->aborted = 1;
                break;
            }
            n -= w;
            o += w;
        }                       /* while client alive and more data to send */

        /* if we've received everything, leave now */
        if (total_bytes_rcvd == len)
            break;

    }                           /* loop and ap_bread while "ok" */

    /* if the backend connection is still open, close it */
    if (f) {
        ap_bclose(f);
    }

    if (!con->aborted) {
        ap_bflush(con->client);
    }

    ap_kill_timeout(r);

    r->bytes_sent += total_bytes_rcvd;

    return total_bytes_rcvd;
}

/*
 * Writes response line and headers to the cache file.
 *
 * If respline is NULL, no response line will be written.
 */
void ap_proxy_write_headers(cache_req *c, const char *respline, table *t)
{
    /* write status line */
    if (respline && c->fp != NULL &&
        ap_bvputs(c->fp, respline, CRLF, NULL) == -1) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                      "proxy: error writing status line to %s", c->tempfile);
        c = ap_proxy_cache_error(c);
        return;
    }

    /* write response headers to the cache file */
    ap_table_do(ap_proxy_send_hdr_line, c, t, NULL);

    /* write terminating CRLF */
    if (c->fp != NULL && ap_bputs(CRLF, c->fp) == -1) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                      "proxy: error writing CRLF to %s", c->tempfile);
        c = ap_proxy_cache_error(c);
    }
}


/*
 * list is a comma-separated list of case-insensitive tokens, with
 * optional whitespace around the tokens.
 * The return returns 1 if the token val is found in the list, or 0
 * otherwise.
 */
int ap_proxy_liststr(const char *list, const char *key, char **val)
{
    int len, i;
    const char *p;
    char valbuf[HUGE_STRING_LEN];
    valbuf[sizeof(valbuf) - 1] = 0;     /* safety terminating zero */

    len = strlen(key);

    while (list != NULL) {
        p = strchr(list, ',');
        if (p != NULL) {
            i = p - list;
            do
                p++;
            while (ap_isspace(*p));
        }
        else
            i = strlen(list);

        while (i > 0 && ap_isspace(list[i - 1]))
            i--;
        if (i == len && strncasecmp(list, key, len) == 0) {
            if (val) {
                p = strchr(list, ',');
                while (ap_isspace(*list)) {
                    list++;
                }
                if ('=' == list[0])
                    list++;
                while (ap_isspace(*list)) {
                    list++;
                }
                strncpy(valbuf, list, MIN(p - list, sizeof(valbuf) - 1));
                *val = valbuf;
            }
            return 1;
        }
        list = p;
    }
    return 0;
}

#ifdef CASE_BLIND_FILESYSTEM

/*
 * On some platforms, the file system is NOT case sensitive. So, a == A
 * need to map to smaller set of characters
 */
void ap_proxy_hash(const char *it, char *val, int ndepth, int nlength)
{
    AP_MD5_CTX context;
    unsigned char digest[16];
    char tmp[26];
    int i, k, d;
    unsigned int x;
    static const char enc_table[32] = "abcdefghijklmnopqrstuvwxyz012345";

    ap_MD5Init(&context);
    ap_MD5Update(&context, (const unsigned char *)it, strlen(it));
    ap_MD5Final(digest, &context);

/* encode 128 bits as 26 characters, using a modified uuencoding */
/* the encoding is 5 bytes -> 8 characters
 * i.e. 128 bits is 3 x 5 bytes + 1 byte -> 3 * 8 characters + 2 characters
 */
    for (i = 0, k = 0; i < 15; i += 5) {
        x = (digest[i] << 24) | (digest[i + 1] << 16) | (digest[i + 2] << 8) | digest[i + 3];
        tmp[k++] = enc_table[x >> 27];
        tmp[k++] = enc_table[(x >> 22) & 0x1f];
        tmp[k++] = enc_table[(x >> 17) & 0x1f];
        tmp[k++] = enc_table[(x >> 12) & 0x1f];
        tmp[k++] = enc_table[(x >> 7) & 0x1f];
        tmp[k++] = enc_table[(x >> 2) & 0x1f];
        x = ((x & 0x3) << 8) | digest[i + 4];
        tmp[k++] = enc_table[x >> 5];
        tmp[k++] = enc_table[x & 0x1f];
    }
/* one byte left */
    x = digest[15];
    tmp[k++] = enc_table[x >> 3];       /* use up 5 bits */
    tmp[k++] = enc_table[x & 0x7];
    /* now split into directory levels */

    for (i = k = d = 0; d < ndepth; ++d) {
        memcpy(&val[i], &tmp[k], nlength);
        k += nlength;
        val[i + nlength] = '/';
        i += nlength + 1;
    }
    memcpy(&val[i], &tmp[k], 26 - k);
    val[i + 26 - k] = '\0';
}

#else

void ap_proxy_hash(const char *it, char *val, int ndepth, int nlength)
{
    AP_MD5_CTX context;
    unsigned char digest[16];
    char tmp[22];
    int i, k, d;
    unsigned int x;
#if defined(MPE) || (defined(AIX) && defined(__ps2__))
    /*
     * Believe it or not, AIX 1.x does not allow you to name a file '@', so
     * hack around it in the encoding.
     */
    static const char enc_table[64] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_%";
#else
    static const char enc_table[64] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_@";
#endif

    ap_MD5Init(&context);
    ap_MD5Update(&context, (const unsigned char *)it, strlen(it));
    ap_MD5Final(digest, &context);

/* encode 128 bits as 22 characters, using a modified uuencoding */
/* the encoding is 3 bytes -> 4 characters
 * i.e. 128 bits is 5 x 3 bytes + 1 byte -> 5 * 4 characters + 2 characters
 */
    for (i = 0, k = 0; i < 15; i += 3) {
        x = (digest[i] << 16) | (digest[i + 1] << 8) | digest[i + 2];
        tmp[k++] = enc_table[x >> 18];
        tmp[k++] = enc_table[(x >> 12) & 0x3f];
        tmp[k++] = enc_table[(x >> 6) & 0x3f];
        tmp[k++] = enc_table[x & 0x3f];
    }
/* one byte left */
    x = digest[15];
    tmp[k++] = enc_table[x >> 2];       /* use up 6 bits */
    tmp[k++] = enc_table[(x << 4) & 0x3f];
    /* now split into directory levels */

    for (i = k = d = 0; d < ndepth; ++d) {
        memcpy(&val[i], &tmp[k], nlength);
        k += nlength;
        val[i + nlength] = '/';
        i += nlength + 1;
    }
    memcpy(&val[i], &tmp[k], 22 - k);
    val[i + 22 - k] = '\0';
}

#endif                          /* CASE_BLIND_FILESYSTEM */

/*
 * Converts 16 hex digits to a time integer
 */
int ap_proxy_hex2sec(const char *x)
{
    int i, ch;
    unsigned int j;

    for (i = 0, j = 0; i < 16; i++) {
        ch = x[i];
        j <<= 4;
        if (ap_isdigit(ch))
            j |= ch - '0';
        else if (ap_isupper(ch))
            j |= ch - ('A' - 10);
        else
            j |= ch - ('a' - 10);
    }
/* no longer necessary, as the source hex is 8-byte int */
/*    if (j == 0xffffffff)*/
    /*      return -1;*//* so that it works with 8-byte ints */
/*    else */
    return j;
}

/*
 * Converts a time integer to 16 hex digits
 */
void ap_proxy_sec2hex(int t, char *y)
{
    int i, ch;
    unsigned int j = t;

    if (-1 == t) {
        strcpy(y, "FFFFFFFFFFFFFFFF");
        return;
    }

    for (i = 15; i >= 0; i--) {
        ch = j & 0xF;
        j >>= 4;
        if (ch >= 10)
            y[i] = ch + ('A' - 10);
        else
            y[i] = ch + '0';
    }
    y[16] = '\0';
}


cache_req *ap_proxy_cache_error(cache_req *c)
{
    if (c != NULL) {
        if (c->fp != NULL) {
            ap_pclosef(c->req->pool, ap_bfileno(c->fp, B_WR));
            c->fp = NULL;
        }
        if (c->origfp != NULL) {
            ap_pclosef(c->req->pool, ap_bfileno(c->origfp, B_WR));
            c->origfp = NULL;
        }
        if (c->tempfile)
            unlink(c->tempfile);
    }
    return NULL;
}

int ap_proxyerror(request_rec *r, int statuscode, const char *message)
{
    ap_table_setn(r->notes, "error-notes",
                  ap_pstrcat(r->pool,
                             "The proxy server could not handle the request "
                           "<EM><A HREF=\"", ap_escape_uri(r->pool, r->uri),
                             "\">", ap_escape_html(r->pool, r->method),
                             "&nbsp;",
                          ap_escape_html(r->pool, r->uri), "</A></EM>.<P>\n"
                             "Reason: <STRONG>",
                             ap_escape_html(r->pool, message),
                             "</STRONG>", NULL));

    /* Allow "error-notes" string to be printed by ap_send_error_response() */
    ap_table_setn(r->notes, "verbose-error-to", ap_pstrdup(r->pool, "*"));

    r->status_line = ap_psprintf(r->pool, "%3.3u Proxy Error", statuscode);
    return statuscode;
}

/*
 * This routine returns its own error message
 */
const char *
     ap_proxy_host2addr(const char *host, struct hostent * reqhp)
{
    int i;
    struct hostent *hp;
    struct per_thread_data *ptd = get_per_thread_data();

    for (i = 0; host[i] != '\0'; i++)
        if (!ap_isdigit(host[i]) && host[i] != '.')
            break;

    if (host[i] != '\0') {
        hp = gethostbyname(host);
        if (hp == NULL)
            return "Host not found";
    }
    else {
        ptd->ipaddr = ap_inet_addr(host);
        hp = gethostbyaddr((char *)&ptd->ipaddr, sizeof(ptd->ipaddr), AF_INET);
        if (hp == NULL) {
            memset(&ptd->hpbuf, 0, sizeof(ptd->hpbuf));
            ptd->hpbuf.h_name = 0;
            ptd->hpbuf.h_addrtype = AF_INET;
            ptd->hpbuf.h_length = sizeof(ptd->ipaddr);
            ptd->hpbuf.h_addr_list = ptd->charpbuf;
            ptd->hpbuf.h_addr_list[0] = (char *)&ptd->ipaddr;
            ptd->hpbuf.h_addr_list[1] = 0;
            hp = &ptd->hpbuf;
        }
    }
    *reqhp = *hp;
    return NULL;
}

static const char *
     proxy_get_host_of_request(request_rec *r)
{
    char *url, *user = NULL, *password = NULL, *err, *host;
    int port = -1;

    if (r->hostname != NULL)
        return r->hostname;

    /* Set url to the first char after "scheme://" */
    if ((url = strchr(r->uri, ':')) == NULL
        || url[1] != '/' || url[2] != '/')
        return NULL;

    url = ap_pstrdup(r->pool, &url[1]); /* make it point to "//", which is
                                         * what proxy_canon_netloc expects */

    err = ap_proxy_canon_netloc(r->pool, &url, &user, &password, &host, &port);

    if (err != NULL)
        ap_log_rerror(APLOG_MARK, APLOG_ERR | APLOG_NOERRNO, r,
                      "%s", err);

    r->hostname = host;

    return host;                /* ought to return the port, too */
}

/* Return TRUE if addr represents an IP address (or an IP network address) */
int ap_proxy_is_ipaddr(struct dirconn_entry *This, pool *p)
{
    const char *addr = This->name;
    long ip_addr[4];
    int i, quads;
    long bits;

    /* if the address is given with an explicit netmask, use that */
    /* Due to a deficiency in ap_inet_addr(), it is impossible to parse */
    /* "partial" addresses (with less than 4 quads) correctly, i.e.  */
    /* 192.168.123 is parsed as 192.168.0.123, which is not what I want. */
    /* I therefore have to parse the IP address manually: */
    /*
     * if (proxy_readmask(This->name, &This->addr.s_addr, &This->mask.s_addr)
     * == 0)
     */
    /* addr and mask were set by proxy_readmask() */
    /* return 1; */

    /* Parse IP addr manually, optionally allowing */
    /* abbreviated net addresses like 192.168. */

    /* Iterate over up to 4 (dotted) quads. */
    for (quads = 0; quads < 4 && *addr != '\0'; ++quads) {
        char *tmp;

        if (*addr == '/' && quads > 0)  /* netmask starts here. */
            break;

        if (!ap_isdigit(*addr))
            return 0;           /* no digit at start of quad */

        ip_addr[quads] = ap_strtol(addr, &tmp, 0);

        if (tmp == addr)        /* expected a digit, found something else */
            return 0;

        if (ip_addr[quads] < 0 || ip_addr[quads] > 255) {
            /* invalid octet */
            return 0;
        }

        addr = tmp;

        if (*addr == '.' && quads != 3)
            ++addr;             /* after the 4th quad, a dot would be illegal */
    }

    for (This->addr.s_addr = 0, i = 0; i < quads; ++i)
        This->addr.s_addr |= htonl(ip_addr[i] << (24 - 8 * i));

    if (addr[0] == '/' && ap_isdigit(addr[1])) {        /* net mask follows: */
        char *tmp;

        ++addr;

        bits = ap_strtol(addr, &tmp, 0);

        if (tmp == addr)        /* expected a digit, found something else */
            return 0;

        addr = tmp;

        if (bits < 0 || bits > 32)      /* netmask must be between 0 and 32 */
            return 0;

    }
    else {
        /* Determine (i.e., "guess") netmask by counting the */
        /* number of trailing .0's; reduce #quads appropriately */
        /* (so that 192.168.0.0 is equivalent to 192.168.)        */
        while (quads > 0 && ip_addr[quads - 1] == 0)
            --quads;

        /*
         * "IP Address should be given in dotted-quad form, optionally
         * followed by a netmask (e.g., 192.168.111.0/24)";
         */
        if (quads < 1)
            return 0;

        /* every zero-byte counts as 8 zero-bits */
        bits = 8 * quads;

        if (bits != 32)         /* no warning for fully qualified IP address */
            fprintf(stderr, "Warning: NetMask not supplied with IP-Addr; guessing: %s/%ld\n",
                    inet_ntoa(This->addr), bits);
    }

    This->mask.s_addr = htonl(INADDR_NONE << (32 - bits));

    if (*addr == '\0' && (This->addr.s_addr & ~This->mask.s_addr) != 0) {
        fprintf(stderr, "Warning: NetMask and IP-Addr disagree in %s/%ld\n",
                inet_ntoa(This->addr), bits);
        This->addr.s_addr &= This->mask.s_addr;
        fprintf(stderr, "         Set to %s/%ld\n",
                inet_ntoa(This->addr), bits);
    }

    if (*addr == '\0') {
        This->matcher = proxy_match_ipaddr;
        return 1;
    }
    else
        return (*addr == '\0'); /* okay iff we've parsed the whole string */
}

/* Return TRUE if addr represents an IP address (or an IP network address) */
static int proxy_match_ipaddr(struct dirconn_entry *This, request_rec *r)
{
    int i;
    int ip_addr[4];
    struct in_addr addr;
    struct in_addr *ip_list;
    char **ip_listptr;
    const char *found;
    const char *host = proxy_get_host_of_request(r);

    if (host == NULL)           /* oops! */
        return 0;

    memset(&addr, '\0', sizeof addr);
    memset(ip_addr, '\0', sizeof ip_addr);

    if (4 == sscanf(host, "%d.%d.%d.%d", &ip_addr[0], &ip_addr[1], &ip_addr[2], &ip_addr[3])) {
        for (addr.s_addr = 0, i = 0; i < 4; ++i)
            addr.s_addr |= htonl(ip_addr[i] << (24 - 8 * i));

        if (This->addr.s_addr == (addr.s_addr & This->mask.s_addr)) {
#if DEBUGGING
            fprintf(stderr, "1)IP-Match: %s[%s] <-> ", host, inet_ntoa(addr));
            fprintf(stderr, "%s/", inet_ntoa(This->addr));
            fprintf(stderr, "%s\n", inet_ntoa(This->mask));
#endif
            return 1;
        }
#if DEBUGGING
        else {
            fprintf(stderr, "1)IP-NoMatch: %s[%s] <-> ", host, inet_ntoa(addr));
            fprintf(stderr, "%s/", inet_ntoa(This->addr));
            fprintf(stderr, "%s\n", inet_ntoa(This->mask));
        }
#endif
    }
    else {
        struct hostent the_host;

        memset(&the_host, '\0', sizeof the_host);
        found = ap_proxy_host2addr(host, &the_host);

        if (found != NULL) {
#if DEBUGGING
            fprintf(stderr, "2)IP-NoMatch: hostname=%s msg=%s\n", host, found);
#endif
            return 0;
        }

        if (the_host.h_name != NULL)
            found = the_host.h_name;
        else
            found = host;

        /* Try to deal with multiple IP addr's for a host */
        for (ip_listptr = the_host.h_addr_list; *ip_listptr; ++ip_listptr) {
            ip_list = (struct in_addr *)*ip_listptr;
            if (This->addr.s_addr == (ip_list->s_addr & This->mask.s_addr)) {
#if DEBUGGING
                fprintf(stderr, "3)IP-Match: %s[%s] <-> ", found, inet_ntoa(*ip_list));
                fprintf(stderr, "%s/", inet_ntoa(This->addr));
                fprintf(stderr, "%s\n", inet_ntoa(This->mask));
#endif
                return 1;
            }
#if DEBUGGING
            else {
                fprintf(stderr, "3)IP-NoMatch: %s[%s] <-> ", found, inet_ntoa(*ip_list));
                fprintf(stderr, "%s/", inet_ntoa(This->addr));
                fprintf(stderr, "%s\n", inet_ntoa(This->mask));
            }
#endif
        }
    }

    return 0;
}

/* Return TRUE if addr represents a domain name */
int ap_proxy_is_domainname(struct dirconn_entry *This, pool *p)
{
    char *addr = This->name;
    int i;

    /* Domain name must start with a '.' */
    if (addr[0] != '.')
        return 0;

    /* rfc1035 says DNS names must consist of "[-a-zA-Z0-9]" and '.' */
    for (i = 0; ap_isalnum(addr[i]) || addr[i] == '-' || addr[i] == '.'; ++i)
        continue;

#if 0
    if (addr[i] == ':') {
        fprintf(stderr, "@@@@ handle optional port in proxy_is_domainname()\n");
        /* @@@@ handle optional port */
    }
#endif

    if (addr[i] != '\0')
        return 0;

    /* Strip trailing dots */
    for (i = strlen(addr) - 1; i > 0 && addr[i] == '.'; --i)
        addr[i] = '\0';

    This->matcher = proxy_match_domainname;
    return 1;
}

/* Return TRUE if host "host" is in domain "domain" */
static int proxy_match_domainname(struct dirconn_entry *This, request_rec *r)
{
    const char *host = proxy_get_host_of_request(r);
    int d_len = strlen(This->name), h_len;

    if (host == NULL)           /* some error was logged already */
        return 0;

    h_len = strlen(host);

    /* @@@ do this within the setup? */
    /* Ignore trailing dots in domain comparison: */
    while (d_len > 0 && This->name[d_len - 1] == '.')
        --d_len;
    while (h_len > 0 && host[h_len - 1] == '.')
        --h_len;
    return h_len > d_len
        && strncasecmp(&host[h_len - d_len], This->name, d_len) == 0;
}

/* Return TRUE if addr represents a host name */
int ap_proxy_is_hostname(struct dirconn_entry *This, pool *p)
{
    struct hostent host;
    char *addr = This->name;
    int i;

    /* Host names must not start with a '.' */
    if (addr[0] == '.')
        return 0;

    /* rfc1035 says DNS names must consist of "[-a-zA-Z0-9]" and '.' */
    for (i = 0; ap_isalnum(addr[i]) || addr[i] == '-' || addr[i] == '.'; ++i);

#if 0
    if (addr[i] == ':') {
        fprintf(stderr, "@@@@ handle optional port in proxy_is_hostname()\n");
        /* @@@@ handle optional port */
    }
#endif

    if (addr[i] != '\0' || ap_proxy_host2addr(addr, &host) != NULL)
        return 0;

    This->hostentry = ap_pduphostent(p, &host);

    /* Strip trailing dots */
    for (i = strlen(addr) - 1; i > 0 && addr[i] == '.'; --i)
        addr[i] = '\0';

    This->matcher = proxy_match_hostname;
    return 1;
}

/* Return TRUE if host "host" is equal to host2 "host2" */
static int proxy_match_hostname(struct dirconn_entry *This, request_rec *r)
{
    char *host = This->name;
    const char *host2 = proxy_get_host_of_request(r);
    int h2_len;
    int h1_len;

    if (host == NULL || host2 == NULL)
        return 0;               /* oops! */

    h2_len = strlen(host2);
    h1_len = strlen(host);

#if 0
    unsigned long *ip_list;

    /* Try to deal with multiple IP addr's for a host */
    for (ip_list = *This->hostentry->h_addr_list; *ip_list != 0UL; ++ip_list)
        if (*ip_list == ? ? ? ? ? ? ? ? ? ? ? ? ?)
            return 1;
#endif

    /* Ignore trailing dots in host2 comparison: */
    while (h2_len > 0 && host2[h2_len - 1] == '.')
        --h2_len;
    while (h1_len > 0 && host[h1_len - 1] == '.')
        --h1_len;
    return h1_len == h2_len
        && strncasecmp(host, host2, h1_len) == 0;
}

/* Return TRUE if addr is to be matched as a word */
int ap_proxy_is_word(struct dirconn_entry *This, pool *p)
{
    This->matcher = proxy_match_word;
    return 1;
}

/* Return TRUE if string "str2" occurs literally in "str1" */
static int proxy_match_word(struct dirconn_entry *This, request_rec *r)
{
    const char *host = proxy_get_host_of_request(r);
    return host != NULL && strstr(host, This->name) != NULL;
}

int ap_proxy_doconnect(int sock, struct sockaddr_in *addr, request_rec *r)
{
    int i;

    ap_hard_timeout("proxy connect", r);
    do {
        i = connect(sock, (struct sockaddr *)addr, sizeof(struct sockaddr_in));
#if defined(WIN32) || defined(NETWARE)
        if (i == SOCKET_ERROR)
            errno = WSAGetLastError();
#endif                          /* WIN32 */
    } while (i == -1 && errno == EINTR);
    if (i == -1) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
                      "proxy connect to %s port %d failed",
                      inet_ntoa(addr->sin_addr), ntohs(addr->sin_port));
    }
    ap_kill_timeout(r);

    return i;
}

/* This function is called by ap_table_do() for all header lines
 * (from proxy_http.c and proxy_ftp.c)
 * It is passed a cache_req struct pointer and a MIME field and value pair
 */
int ap_proxy_send_hdr_line(void *p, const char *key, const char *value)
{
    cache_req *c = (cache_req *)p;

    if (key == NULL || value == NULL || value[0] == '\0')
        return 1;
    if (c->fp != NULL &&
        ap_bvputs(c->fp, key, ": ", value, CRLF, NULL) == -1) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, c->req,
                      "proxy: error writing header to %s", c->tempfile);
        c = ap_proxy_cache_error(c);
        return 0;               /* no need to continue, it failed already */
    }
    return 1;                   /* tell ap_table_do() to continue calling us
                                 * for more headers */
}

/* send a text line to one or two BUFF's; return line length */
unsigned ap_proxy_bputs2(const char *data, BUFF *client, cache_req *cache)
{
    unsigned len = ap_bputs(data, client);
    if (cache != NULL && cache->fp != NULL)
        ap_bputs(data, cache->fp);
    return len;
}

/* do a HTTP/1.1 age calculation */
time_t ap_proxy_current_age(cache_req *c, const time_t age_value)
{
    time_t apparent_age, corrected_received_age, response_delay, corrected_initial_age,
           resident_time, current_age;

    /* Perform an HTTP/1.1 age calculation. (RFC2616 13.2.3) */

    apparent_age = MAX(0, c->resp_time - c->date);
    corrected_received_age = MAX(apparent_age, age_value);
    response_delay = c->resp_time - c->req_time;
    corrected_initial_age = corrected_received_age + response_delay;
    resident_time = time(NULL) - c->resp_time;
    current_age = corrected_initial_age + resident_time;

    return (current_age);
}

/* open a cache file and return a pointer to a BUFF */
BUFF *ap_proxy_open_cachefile(request_rec *r, char *filename)
{
    BUFF *cachefp = NULL;
    int cfd;

    if (filename != NULL) {
        cfd = open(filename, O_RDWR | O_BINARY);
        if (cfd != -1) {
            ap_note_cleanups_for_fd(r->pool, cfd);
            cachefp = ap_bcreate(r->pool, B_RD | B_WR);
            ap_bpushfd(cachefp, cfd, cfd);
        }
        else if (errno != ENOENT)
            ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
                          "proxy: error opening cache file %s",
                          filename);
        else
            ap_log_error(APLOG_MARK, APLOG_DEBUG | APLOG_NOERRNO, r->server, "File %s not found", filename);

    }
    return cachefp;
}

/* create a cache file and return a pointer to a BUFF */
BUFF *ap_proxy_create_cachefile(request_rec *r, char *filename)
{
    BUFF *cachefp = NULL;
    int cfd;

    if (filename != NULL) {
        cfd = open(filename, O_WRONLY | O_CREAT | O_EXCL | O_BINARY, 0622);
        if (cfd != -1) {
            ap_note_cleanups_for_fd(r->pool, cfd);
            cachefp = ap_bcreate(r->pool, B_WR);
            ap_bpushfd(cachefp, -1, cfd);
        }
        else if (errno != ENOENT)
            ap_log_rerror(APLOG_MARK, APLOG_ERR, r,
                          "proxy: error creating cache file %s",
                          filename);
    }
    return cachefp;
}

/* Clear all connection-based headers from headers table */
void ap_proxy_clear_connection(pool *p, table *headers)
{
    const char *name;
    char *next = ap_pstrdup(p, ap_table_get(headers, "Connection"));

    /* Some proxies (Squid, ICS) use the non-standard "Proxy-Connection" header. */
    ap_table_unset(headers, "Proxy-Connection");

    if (next != NULL) {
        while (*next) {
            name = next;
            while (*next && !ap_isspace(*next) && (*next != ','))
                ++next;
            while (*next && (ap_isspace(*next) || (*next == ','))) {
                *next = '\0';
                ++next;
            }
            ap_table_unset(headers, name);
        }
        ap_table_unset(headers, "Connection");
    }

    /* unset hop-by-hop headers defined in RFC2616 13.5.1 */
    ap_table_unset(headers,"Keep-Alive");
    /*
     * XXX: @@@ FIXME: "Proxy-Authenticate" should IMO *not* be stripped
     * because in a chain of proxies some "front" proxy might need
     * proxy authentication, while a "back-end" proxy which needs none can
     * simply pass the "Proxy-Authenticate" back to the client, and pass
     * the client's "Proxy-Authorization" to the front-end proxy.
     * (See the note in proxy_http.c for the "Proxy-Authorization" case.)
     *
     *   MnKr 04/2002
     */
    ap_table_unset(headers,"Proxy-Authenticate");
    ap_table_unset(headers,"TE");
    ap_table_unset(headers,"Trailer");
    /* it is safe to just chop the transfer-encoding header
     * here, because proxy doesn't support any other encodings
     * to the backend other than chunked.
     */
    ap_table_unset(headers,"Transfer-Encoding");
    ap_table_unset(headers,"Upgrade");

}

/* overlay one table on another
 * keys in base will be replaced by keys in overlay
 *
 * Note: this has to be done in a special way, due
 * to some nastiness when it comes to having multiple
 * headers in the overlay table. First, we remove all
 * the headers in the base table that are found in the
 * overlay table, then we simply concatenate the
 * tables together.
 *
 * The base and overlay tables need not be in the same
 * pool (and probably won't be).
 *
 * If the base table is changed in any way through
 * being overlayed with the overlay table, this
 * function returns a 1.
 */
int ap_proxy_table_replace(table *base, table *overlay)
{
    table_entry *elts = (table_entry *)overlay->a.elts;
    int i, q = 0;
    const char *val;

    /* remove overlay's keys from base */
    for (i = 0; i < overlay->a.nelts; ++i) {
        val = ap_table_get(base, elts[i].key);
        if (!val || strcmp(val, elts[i].val)) {
            q = 1;
        }
        if (val) {
            ap_table_unset(base, elts[i].key);
        }
    }

    /* add overlay to base */
    for (i = 0; i < overlay->a.nelts; ++i) {
        ap_table_add(base, elts[i].key, elts[i].val);
    }

    return q;
}

/* read the response line
 * This function reads a single line of response from the server,
 * and returns a status code.
 * It also populates the request_rec with the resultant status, and
 * returns backasswards status (HTTP/0.9).
 */
int ap_proxy_read_response_line(BUFF *f, request_rec *r, char *buffer, int size, int *backasswards, int *major, int *minor) {

    long len;

    len = ap_getline(buffer, size-1, f, 0);
    if (len == -1) {
        ap_bclose(f);
        ap_kill_timeout(r);
        return ap_proxyerror(r, HTTP_BAD_GATEWAY,
                             "Error reading from remote server");
    }
    else if (len == 0) {
        ap_bclose(f);
        ap_kill_timeout(r);
        return ap_proxyerror(r, HTTP_BAD_GATEWAY,
                             "Document contains no data");
    }

    /*
     * Is it an HTTP/1 response? Do some sanity checks on the response. (This
     * is buggy if we ever see an HTTP/1.10)
     */
    if (ap_checkmask(buffer, "HTTP/#.# ###*")) {

        if (2 != sscanf(buffer, "HTTP/%u.%u", major, minor)) {
            /* if no response, default to HTTP/1.1 - is this correct? */
            *major = 1;
            *minor = 1;
        }

        /* If not an HTTP/1 message */
        if (*major < 1) {
            ap_bclose(f);
            ap_kill_timeout(r);
            return HTTP_BAD_GATEWAY;
        }
        *backasswards = 0;

        buffer[12] = '\0';
        r->status = atoi(&buffer[9]);
        buffer[12] = ' ';
        r->status_line = ap_pstrdup(r->pool, &buffer[9]);

        /* if the response was 100 continue, soak up any headers */
        if (r->status == 100) {
            ap_proxy_read_headers(r, buffer, size, f);
        }

    }
    else {

        /* an http/0.9 response */
        *backasswards = 1;
        r->status = 200;
        r->status_line = "200 OK";
        *major = 0;
        *minor = 9;

    }

    return OK;

}


#if defined WIN32

static DWORD tls_index;

BOOL WINAPI DllMain(HINSTANCE dllhandle, DWORD reason, LPVOID reserved)
{
    LPVOID memptr;

    switch (reason) {
    case DLL_PROCESS_ATTACH:
        tls_index = TlsAlloc();
    case DLL_THREAD_ATTACH:     /* intentional no break */
        TlsSetValue(tls_index, malloc(sizeof(struct per_thread_data)));
        break;
    case DLL_THREAD_DETACH:
        memptr = TlsGetValue(tls_index);
        if (memptr) {
            free(memptr);
            TlsSetValue(tls_index, 0);
        }
        break;
    }

    return TRUE;
}

#endif

static struct per_thread_data *get_per_thread_data(void)
{
#if defined(WIN32)

    return (struct per_thread_data *)TlsGetValue(tls_index);

#else

    static APACHE_TLS struct per_thread_data sptd;
    return &sptd;

#endif
}
