mod_proxy.c

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "mod_proxy.h"
#include "mod_core.h"
#include "apr_optional.h"
#include "scoreboard.h"
#include "mod_status.h"
#include "proxy_util.h"

#if (MODULE_MAGIC_NUMBER_MAJOR > 20020903)
#include "mod_ssl.h"
#else
APR_DECLARE_OPTIONAL_FN(int, ssl_proxy_enable, (conn_rec *));
APR_DECLARE_OPTIONAL_FN(int, ssl_engine_disable, (conn_rec *));
APR_DECLARE_OPTIONAL_FN(int, ssl_is_https, (conn_rec *));
APR_DECLARE_OPTIONAL_FN(char *, ssl_var_lookup,
                        (apr_pool_t *, server_rec *,
                         conn_rec *, request_rec *, char *));
#endif

#ifndef MAX
#define MAX(x,y) ((x) >= (y) ? (x) : (y))
#endif

/*
 * We do health-checks only if that (sub)module is loaded in. This
 * allows for us to continue as is w/o requiring mod_watchdog for
 * those implementations which aren't using health checks
 */
static APR_OPTIONAL_FN_TYPE(set_worker_hc_param) *set_worker_hc_param_f = NULL;

/* Externals */
proxy_hcmethods_t PROXY_DECLARE_DATA proxy_hcmethods[] = {
    {NONE, "NONE", 1},
    {TCP, "TCP", 1},
    {OPTIONS, "OPTIONS", 1},
    {HEAD, "HEAD", 1},
    {GET, "GET", 1},
    {CPING, "CPING", 0},
    {PROVIDER, "PROVIDER", 0},
    {EOT, NULL, 1}
};

proxy_wstat_t PROXY_DECLARE_DATA proxy_wstat_tbl[] = {
    {PROXY_WORKER_INITIALIZED,   PROXY_WORKER_INITIALIZED_FLAG,   "Init "},
    {PROXY_WORKER_IGNORE_ERRORS, PROXY_WORKER_IGNORE_ERRORS_FLAG, "Ign "},
    {PROXY_WORKER_DRAIN,         PROXY_WORKER_DRAIN_FLAG,         "Drn "},
    {PROXY_WORKER_GENERIC,       PROXY_WORKER_GENERIC_FLAG,       "Gen "},
    {PROXY_WORKER_IN_SHUTDOWN,   PROXY_WORKER_IN_SHUTDOWN_FLAG,   "Shut "},
    {PROXY_WORKER_DISABLED,      PROXY_WORKER_DISABLED_FLAG,      "Dis "},
    {PROXY_WORKER_STOPPED,       PROXY_WORKER_STOPPED_FLAG,       "Stop "},
    {PROXY_WORKER_IN_ERROR,      PROXY_WORKER_IN_ERROR_FLAG,      "Err "},
    {PROXY_WORKER_HOT_STANDBY,   PROXY_WORKER_HOT_STANDBY_FLAG,   "Stby "},
    {PROXY_WORKER_FREE,          PROXY_WORKER_FREE_FLAG,          "Free "},
    {PROXY_WORKER_HC_FAIL,       PROXY_WORKER_HC_FAIL_FLAG,       "HcFl "},
    {0x0, '\0', NULL}
};

static const char * const proxy_id = "proxy";
apr_global_mutex_t *proxy_mutex = NULL;

/*
 * A Web proxy module. Stages:
 *
 *  translate_name: set filename to proxy:<URL>
 *  map_to_storage: run proxy_walk (rather than directory_walk/file_walk)
 *                  can't trust directory_walk/file_walk since these are
 *                  not in our filesystem.  Prevents mod_http from serving
 *                  the TRACE request we will set aside to handle later.
 *  fix_ups:        convert the URL stored in the filename to the
 *                  canonical form.
 *  handler:        handle proxy requests
 */

/* -------------------------------------------------------------- */
/* Translate the URL into a 'filename' */

static const char *set_worker_param(apr_pool_t *p,
                                    server_rec *s,
                                    proxy_worker *worker,
                                    const char *key,
                                    const char *val)
{

    int ival;
    apr_interval_time_t timeout;

    if (!strcasecmp(key, "loadfactor")) {
        /* Normalized load factor. Used with BalancerMember,
         * it is a number between 1 and 100.
         */
        double fval = atof(val);
        ival = fval * 100.0;
        if (ival < 100 || ival > 10000)
            return "LoadFactor must be a number between 1..100";
        worker->s->lbfactor = ival;
    }
    else if (!strcasecmp(key, "retry")) {
        /* If set it will give the retry timeout for the worker
         * The default value is 60 seconds, meaning that if
         * in error state, it will be retried after that timeout.
         */
        ival = atoi(val);
        if (ival < 0)
            return "Retry must be a positive value";
        worker->s->retry = apr_time_from_sec(ival);
        worker->s->retry_set = 1;
    }
    else if (!strcasecmp(key, "ttl")) {
        /* Time in seconds that will destroy all the connections
         * that exceed the smax
         */
        ival = atoi(val);
        if (ival < 1)
            return "TTL must be at least one second";
        worker->s->ttl = apr_time_from_sec(ival);
    }
    else if (!strcasecmp(key, "min")) {
        /* Initial number of connections to remote
         */
        ival = atoi(val);
        if (ival < 0)
            return "Min must be a positive number";
        worker->s->min = ival;
    }
    else if (!strcasecmp(key, "max")) {
        /* Maximum number of connections to remote
         */
        ival = atoi(val);
        if (ival < 0)
            return "Max must be a positive number";
        worker->s->hmax = ival;
    }
    /* XXX: More inteligent naming needed */
    else if (!strcasecmp(key, "smax")) {
        /* Maximum number of connections to remote that
         * will not be destroyed
         */
        ival = atoi(val);
        if (ival < 0)
            return "Smax must be a positive number";
        worker->s->smax = ival;
    }
    else if (!strcasecmp(key, "acquire")) {
        /* Acquire timeout in given unit (default is milliseconds).
         * If set this will be the maximum time to
         * wait for a free connection.
         */
        if (ap_timeout_parameter_parse(val, &timeout, "ms") != APR_SUCCESS)
            return "Acquire timeout has wrong format";
        if (timeout < 1000)
            return "Acquire must be at least one millisecond";
        worker->s->acquire = timeout;
        worker->s->acquire_set = 1;
    }
    else if (!strcasecmp(key, "timeout")) {
        /* Connection timeout in seconds.
         * Defaults to server timeout.
         */
        ival = atoi(val);
        if (ival < 1)
            return "Timeout must be at least one second";
        worker->s->timeout = apr_time_from_sec(ival);
        worker->s->timeout_set = 1;
    }
    else if (!strcasecmp(key, "iobuffersize")) {
        long s = atol(val);
        if (s < 512 && s) {
            return "IOBufferSize must be >= 512 bytes, or 0 for system default.";
        }
        worker->s->io_buffer_size = (s ? s : AP_IOBUFSIZE);
        worker->s->io_buffer_size_set = 1;
    }
    else if (!strcasecmp(key, "receivebuffersize")) {
        ival = atoi(val);
        if (ival < 512 && ival != 0) {
            return "ReceiveBufferSize must be >= 512 bytes, or 0 for system default.";
        }
        worker->s->recv_buffer_size = ival;
        worker->s->recv_buffer_size_set = 1;
    }
    else if (!strcasecmp(key, "keepalive")) {
        if (!strcasecmp(val, "on"))
            worker->s->keepalive = 1;
        else if (!strcasecmp(val, "off"))
            worker->s->keepalive = 0;
        else
            return "KeepAlive must be On|Off";
        worker->s->keepalive_set = 1;
    }
    else if (!strcasecmp(key, "disablereuse")) {
        if (!strcasecmp(val, "on"))
            worker->s->disablereuse = 1;
        else if (!strcasecmp(val, "off"))
            worker->s->disablereuse = 0;
        else
            return "DisableReuse must be On|Off";
        worker->s->disablereuse_set = 1;
    }
    else if (!strcasecmp(key, "enablereuse")) {
        if (!strcasecmp(val, "on"))
            worker->s->disablereuse = 0;
        else if (!strcasecmp(val, "off"))
            worker->s->disablereuse = 1;
        else
            return "EnableReuse must be On|Off";
        worker->s->disablereuse_set = 1;
    }
    else if (!strcasecmp(key, "route")) {
        /* Worker route.
         */
        if (strlen(val) >= sizeof(worker->s->route))
            return apr_psprintf(p, "Route length must be < %d characters",
                    (int)sizeof(worker->s->route));
        PROXY_STRNCPY(worker->s->route, val);
    }
    else if (!strcasecmp(key, "redirect")) {
        /* Worker redirection route.
         */
        if (strlen(val) >= sizeof(worker->s->redirect))
            return apr_psprintf(p, "Redirect length must be < %d characters",
                    (int)sizeof(worker->s->redirect));
        PROXY_STRNCPY(worker->s->redirect, val);
    }
    else if (!strcasecmp(key, "status")) {
        const char *v;
        int mode = 1;
        apr_status_t rv;
        /* Worker status.
         */
        for (v = val; *v; v++) {
            if (*v == '+') {
                mode = 1;
                v++;
            }
            else if (*v == '-') {
                mode = 0;
                v++;
            }
            rv = ap_proxy_set_wstatus(*v, mode, worker);
            if (rv != APR_SUCCESS)
                return "Unknown status parameter option";
        }
    }
    else if (!strcasecmp(key, "flushpackets")) {
        if (!strcasecmp(val, "on"))
            worker->s->flush_packets = flush_on;
        else if (!strcasecmp(val, "off"))
            worker->s->flush_packets = flush_off;
        else if (!strcasecmp(val, "auto"))
            worker->s->flush_packets = flush_auto;
        else
            return "flushpackets must be on|off|auto";
    }
    else if (!strcasecmp(key, "flushwait")) {
        ival = atoi(val);
        if (ival > 1000 || ival < 0) {
            return "flushwait must be <= 1000, or 0 for system default of 10 millseconds.";
        }
        if (ival == 0)
            worker->s->flush_wait = PROXY_FLUSH_WAIT;
        else
            worker->s->flush_wait = ival * 1000;    /* change to microseconds */
    }
    else if (!strcasecmp(key, "ping")) {
        /* Ping/Pong timeout in given unit (default is second).
         */
        if (ap_timeout_parameter_parse(val, &timeout, "s") != APR_SUCCESS)
            return "Ping/Pong timeout has wrong format";
        if (timeout < 1000)
            return "Ping/Pong timeout must be at least one millisecond";
        worker->s->ping_timeout = timeout;
        worker->s->ping_timeout_set = 1;
    }
    else if (!strcasecmp(key, "lbset")) {
        ival = atoi(val);
        if (ival < 0 || ival > 99)
            return "lbset must be between 0 and 99";
        worker->s->lbset = ival;
    }
    else if (!strcasecmp(key, "connectiontimeout")) {
        /* Request timeout in given unit (default is second).
         * Defaults to connection timeout
         */
        if (ap_timeout_parameter_parse(val, &timeout, "s") != APR_SUCCESS)
            return "Connectiontimeout has wrong format";
        if (timeout < 1000)
            return "Connectiontimeout must be at least one millisecond.";
        worker->s->conn_timeout = timeout;
        worker->s->conn_timeout_set = 1;
    }
    else if (!strcasecmp(key, "flusher")) {
        if (strlen(val) >= sizeof(worker->s->flusher))
            apr_psprintf(p, "flusher name length must be < %d characters",
                    (int)sizeof(worker->s->flusher));
        PROXY_STRNCPY(worker->s->flusher, val);
    }
    else if (!strcasecmp(key, "upgrade")) {
        if (PROXY_STRNCPY(worker->s->upgrade, val) != APR_SUCCESS) {
            return apr_psprintf(p, "upgrade protocol length must be < %d characters",
                                (int)sizeof(worker->s->upgrade));
        }
    }
    else {
        if (set_worker_hc_param_f) {
            return set_worker_hc_param_f(p, s, worker, key, val, NULL);
        } else {
            return "unknown Worker parameter";
        }
    }
    return NULL;
}

static const char *set_balancer_param(proxy_server_conf *conf,
                                      apr_pool_t *p,
                                      proxy_balancer *balancer,
                                      const char *key,
                                      const char *val)
{

    int ival;
    if (!strcasecmp(key, "stickysession")) {
        char *path;
        /* Balancer sticky session name.
         * Set to something like JSESSIONID or
         * PHPSESSIONID, etc..,
         */
        if (strlen(val) >= sizeof(balancer->s->sticky_path))
            apr_psprintf(p, "stickysession length must be < %d characters",
                    (int)sizeof(balancer->s->sticky_path));
        PROXY_STRNCPY(balancer->s->sticky_path, val);
        PROXY_STRNCPY(balancer->s->sticky, val);

        if ((path = strchr((char *)balancer->s->sticky, '|'))) {
            *path++ = '\0';
            PROXY_STRNCPY(balancer->s->sticky_path, path);
        }
    }
    else if (!strcasecmp(key, "stickysessionsep")) {
        /* separator/delimiter for sessionid and route,
         * normally '.'
         */
        if (strlen(val) != 1) {
            if (!strcasecmp(val, "off"))
                balancer->s->sticky_separator = 0;
            else      
                return "stickysessionsep must be a single character or Off";
        }
        else
            balancer->s->sticky_separator = *val;
    }
    else if (!strcasecmp(key, "nofailover")) {
        /* If set to 'on' the session will break
         * if the worker is in error state or
         * disabled.
         */
        if (!strcasecmp(val, "on"))
            balancer->s->sticky_force = 1;
        else if (!strcasecmp(val, "off"))
            balancer->s->sticky_force = 0;
        else
            return "failover must be On|Off";
    }
    else if (!strcasecmp(key, "timeout")) {
        /* Balancer timeout in seconds.
         * If set this will be the maximum time to
         * wait for a free worker.
         * Default is not to wait.
         */
        ival = atoi(val);
        if (ival < 1)
            return "timeout must be at least one second";
        balancer->s->timeout = apr_time_from_sec(ival);
    }
    else if (!strcasecmp(key, "maxattempts")) {
        /* Maximum number of failover attempts before
         * giving up.
         */
        ival = atoi(val);
        if (ival < 0)
            return "maximum number of attempts must be a positive number";
        balancer->s->max_attempts = ival;
        balancer->s->max_attempts_set = 1;
    }
    else if (!strcasecmp(key, "lbmethod")) {
        proxy_balancer_method *provider;
        if (strlen(val) > (sizeof(balancer->s->lbpname)-1))
            return "unknown lbmethod";
        provider = ap_lookup_provider(PROXY_LBMETHOD, val, "0");
        if (provider) {
            balancer->lbmethod = provider;
            if (PROXY_STRNCPY(balancer->s->lbpname, val) == APR_SUCCESS) {
                return NULL;
            }
            else {
                return "lbmethod name too large";
            }
        }
        return "unknown lbmethod";
    }
    else if (!strcasecmp(key, "scolonpathdelim")) {
        /* If set to 'on' then ';' will also be
         * used as a session path separator/delim (ala
         * mod_jk)
         */
        if (!strcasecmp(val, "on"))
            balancer->s->scolonsep = 1;
        else if (!strcasecmp(val, "off"))
            balancer->s->scolonsep = 0;
        else
            return "scolonpathdelim must be On|Off";
    }
    else if (!strcasecmp(key, "failonstatus")) {
        char *val_split;
        char *status;
        char *tok_state;

        val_split = apr_pstrdup(p, val);

        balancer->errstatuses = apr_array_make(p, 1, sizeof(int));

        status = apr_strtok(val_split, ", ", &tok_state);
        while (status != NULL) {
            ival = atoi(status);
            if (ap_is_HTTP_VALID_RESPONSE(ival)) {
                *(int *)apr_array_push(balancer->errstatuses) = ival;
            }
            else {
                return "failonstatus must be one or more HTTP response codes";
            }
            status = apr_strtok(NULL, ", ", &tok_state);
        }

    }
    else if (!strcasecmp(key, "failontimeout")) {
        if (!strcasecmp(val, "on"))
            balancer->failontimeout = 1;
        else if (!strcasecmp(val, "off"))
            balancer->failontimeout = 0;
        else
            return "failontimeout must be On|Off";
    }
    else if (!strcasecmp(key, "nonce")) {
        if (!strcasecmp(val, "None")) {
            *balancer->s->nonce = '\0';
        }
        else {
            if (PROXY_STRNCPY(balancer->s->nonce, val) != APR_SUCCESS) {
                return "Provided nonce is too large";
            }
        }
    }
    else if (!strcasecmp(key, "growth")) {
        ival = atoi(val);
        if (ival < 1 || ival > 100)   /* arbitrary limit here */
            return "growth must be between 1 and 100";
        balancer->growth = ival;
    }
    else if (!strcasecmp(key, "forcerecovery")) {
        if (!strcasecmp(val, "on"))
            balancer->s->forcerecovery = 1;
        else if (!strcasecmp(val, "off"))
            balancer->s->forcerecovery = 0;
        else
            return "forcerecovery must be On|Off";
    }
    else {
        return "unknown Balancer parameter";
    }
    return NULL;
}

static int alias_match(const char *uri, const char *alias_fakename)
{
    const char *end_fakename = alias_fakename + strlen(alias_fakename);
    const char *aliasp = alias_fakename, *urip = uri;
    const char *end_uri = uri + strlen(uri);

    while (aliasp < end_fakename && urip < end_uri) {
        if (*aliasp == '/') {
            /* any number of '/' in the alias matches any number in
             * the supplied URI, but there must be at least one...
             */
            if (*urip != '/')
                return 0;

            while (*aliasp == '/')
                ++aliasp;
            while (*urip == '/')
                ++urip;
        }
        else {
            /* Other characters are compared literally */
            if (*urip++ != *aliasp++)
                return 0;
        }
    }

    /* fixup badly encoded stuff (e.g. % as last character) */
    if (aliasp > end_fakename) {
        aliasp = end_fakename;
    }
    if (urip > end_uri) {
        urip = end_uri;
    }

   /* We reach the end of the uri before the end of "alias_fakename"
    * for example uri is "/" and alias_fakename "/examples"
    */
   if (urip == end_uri && aliasp != end_fakename) {
       return 0;
   }

    /* Check last alias path component matched all the way */
    if (aliasp[-1] != '/' && *urip != '\0' && *urip != '/')
        return 0;

    /* Return number of characters from URI which matched (may be
     * greater than length of alias, since we may have matched
     * doubled slashes)
     */

    return urip - uri;
}

/* Detect if an absoluteURI should be proxied or not.  Note that we
 * have to do this during this phase because later phases are
 * "short-circuiting"... i.e. translate_names will end when the first
 * module returns OK.  So for example, if the request is something like:
 *
 * GET http://othervhost/cgi-bin/printenv HTTP/1.0
 *
 * mod_alias will notice the /cgi-bin part and ScriptAlias it and
 * short-circuit the proxy... just because of the ordering in the
 * configuration file.
 */
static int proxy_detect(request_rec *r)
{
    void *sconf = r->server->module_config;
    proxy_server_conf *conf =
        (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);

    /* Ick... msvc (perhaps others) promotes ternary short results to int */

    if (conf->req && r->parsed_uri.scheme) {
        /* but it might be something vhosted */
        if (!(r->parsed_uri.hostname
              && !strcasecmp(r->parsed_uri.scheme, ap_http_scheme(r))
              && ap_matches_request_vhost(r, r->parsed_uri.hostname,
                                          (apr_port_t)(r->parsed_uri.port_str ? r->parsed_uri.port
                                                       : ap_default_port(r))))) {
            r->proxyreq = PROXYREQ_PROXY;
            r->uri = r->unparsed_uri;
            r->filename = apr_pstrcat(r->pool, "proxy:", r->uri, NULL);
            r->handler = "proxy-server";
        }
    }
    /* We need special treatment for CONNECT proxying: it has no scheme part */
    else if (conf->req && r->method_number == M_CONNECT
             && r->parsed_uri.hostname
             && r->parsed_uri.port_str) {
        r->proxyreq = PROXYREQ_PROXY;
        r->uri = r->unparsed_uri;
        r->filename = apr_pstrcat(r->pool, "proxy:", r->uri, NULL);
        r->handler = "proxy-server";
    }
    return DECLINED;
}

static const char *proxy_interpolate(request_rec *r, const char *str)
{
    /* Interpolate an env str in a configuration string
     * Syntax ${var} --> value_of(var)
     * Method: replace one var, and recurse on remainder of string
     * Nothing clever here, and crap like nested vars may do silly things
     * but we'll at least avoid sending the unwary into a loop
     */
    const char *start;
    const char *end;
    const char *var;
    const char *val;
    const char *firstpart;

    start = ap_strstr_c(str, "${");
    if (start == NULL) {
        return str;
    }
    end = ap_strchr_c(start+2, '}');
    if (end == NULL) {
        return str;
    }
    /* OK, this is syntax we want to interpolate.  Is there such a var ? */
    var = apr_pstrmemdup(r->pool, start+2, end-(start+2));
    val = apr_table_get(r->subprocess_env, var);
    firstpart = apr_pstrmemdup(r->pool, str, (start-str));

    if (val == NULL) {
        return apr_pstrcat(r->pool, firstpart,
                           proxy_interpolate(r, end+1), NULL);
    }
    else {
        return apr_pstrcat(r->pool, firstpart, val,
                           proxy_interpolate(r, end+1), NULL);
    }
}
static apr_array_header_t *proxy_vars(request_rec *r,
                                      apr_array_header_t *hdr)
{
    int i;
    apr_array_header_t *ret = apr_array_make(r->pool, hdr->nelts,
                                             sizeof (struct proxy_alias));
    struct proxy_alias *old = (struct proxy_alias *) hdr->elts;

    for (i = 0; i < hdr->nelts; ++i) {
        struct proxy_alias *newcopy = apr_array_push(ret);
        newcopy->fake = (old[i].flags & PROXYPASS_INTERPOLATE)
                        ? proxy_interpolate(r, old[i].fake) : old[i].fake;
        newcopy->real = (old[i].flags & PROXYPASS_INTERPOLATE)
                        ? proxy_interpolate(r, old[i].real) : old[i].real;
    }
    return ret;
}

PROXY_DECLARE(int) ap_proxy_trans_match(request_rec *r, struct proxy_alias *ent,
                                        proxy_dir_conf *dconf)
{
    int len;
    const char *fake;
    const char *real;
    ap_regmatch_t regm[AP_MAX_REG_MATCH];
    ap_regmatch_t reg1[AP_MAX_REG_MATCH];
    char *found = NULL;
    int mismatch = 0;
    unsigned int nocanon = ent->flags & PROXYPASS_NOCANON;
    const char *use_uri = nocanon ? r->unparsed_uri : r->uri;

    if (dconf && (dconf->interpolate_env == 1) && (ent->flags & PROXYPASS_INTERPOLATE)) {
        fake = proxy_interpolate(r, ent->fake);
        real = proxy_interpolate(r, ent->real);
    }
    else {
        fake = ent->fake;
        real = ent->real;
    }

    ap_log_rerror(APLOG_MARK, APLOG_TRACE2, 0, r, APLOGNO(03461)
                  "attempting to match URI path '%s' against %s '%s' for "
                  "proxying", r->uri, (ent->regex ? "pattern" : "prefix"),
                  fake);

    if (ent->regex) {
        if (!ap_regexec(ent->regex, r->uri, AP_MAX_REG_MATCH, regm, 0)) {
            if ((real[0] == '!') && (real[1] == '\0')) {
                ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, APLOGNO(03462)
                              "proxying is explicitly disabled for URI path "
                              "'%s'; declining", r->uri);
                return DECLINED;
            }
            /* test that we haven't reduced the URI */
            if (nocanon && ap_regexec(ent->regex, r->unparsed_uri,
                    AP_MAX_REG_MATCH, reg1, 0)) {
                mismatch = 1;
                use_uri = r->uri;
            }
            found = ap_pregsub(r->pool, real, use_uri, AP_MAX_REG_MATCH,
                    (use_uri == r->uri) ? regm : reg1);
            if (!found) {
                ap_log_rerror(APLOG_MARK, APLOG_CRIT, 0, r, APLOGNO(01135)
                              "Substitution in regular expression failed. "
                              "Replacement too long?");
                return HTTP_INTERNAL_SERVER_ERROR;
            }

            /* Note: The strcmp() below catches cases where there
             * was no regex substitution. This is so cases like:
             *
             *    ProxyPassMatch \.gif balancer://foo
             *
             * will work "as expected". The upshot is that the 2
             * directives below act the exact same way (ie: $1 is implied):
             *
             *    ProxyPassMatch ^(/.*\.gif)$ balancer://foo
             *    ProxyPassMatch ^(/.*\.gif)$ balancer://foo$1
             *
             * which may be confusing.
             */
            if (strcmp(found, real) != 0) {
                found = apr_pstrcat(r->pool, "proxy:", found, NULL);
            }
            else {
                found = apr_pstrcat(r->pool, "proxy:", real, use_uri, NULL);
            }
        }
    }
    else {
        len = alias_match(r->uri, fake);

        if (len != 0) {
            if ((real[0] == '!') && (real[1] == '\0')) {
                ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, APLOGNO(03463)
                              "proxying is explicitly disabled for URI path "
                              "'%s'; declining", r->uri);
                return DECLINED;
            }
            if (nocanon && len != alias_match(r->unparsed_uri, ent->fake)) {
                mismatch = 1;
                use_uri = r->uri;
            }
            found = apr_pstrcat(r->pool, "proxy:", real, use_uri + len, NULL);
        }
    }
    if (mismatch) {
        /* We made a reducing transformation, so we can't safely use
         * unparsed_uri.  Safe fallback is to ignore nocanon.
         */
        ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(01136)
                "Unescaped URL path matched ProxyPass; ignoring unsafe nocanon");
    }

    if (found) {
        r->filename = found;
        r->handler = "proxy-server";
        r->proxyreq = PROXYREQ_REVERSE;
        if (nocanon && !mismatch) {
            /* mod_proxy_http needs to be told.  Different module. */
            apr_table_setn(r->notes, "proxy-nocanon", "1");
        }
        if (ent->flags & PROXYPASS_NOQUERY) {
            apr_table_setn(r->notes, "proxy-noquery", "1");
        }

        ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, APLOGNO(03464)
                      "URI path '%s' matches proxy handler '%s'", r->uri,
                      found);

        return OK;
    }

    return DONE;
}

static int proxy_trans(request_rec *r)
{
    int i;
    struct proxy_alias *ent;
    proxy_dir_conf *dconf;
    proxy_server_conf *conf;

    if (r->proxyreq) {
        /* someone has already set up the proxy, it was possibly ourselves
         * in proxy_detect
         */
        return OK;
    }

    if ((r->unparsed_uri[0] == '*' && r->unparsed_uri[1] == '\0')
        || !r->uri || r->uri[0] != '/') {
        return DECLINED;
    }
   
    if (apr_table_get(r->subprocess_env, "no-proxy")) { 
        return DECLINED;
    }

    /* XXX: since r->uri has been manipulated already we're not really
     * compliant with RFC1945 at this point.  But this probably isn't
     * an issue because this is a hybrid proxy/origin server.
     */

    dconf = ap_get_module_config(r->per_dir_config, &proxy_module);

    /* short way - this location is reverse proxied? */
    if (dconf->alias) {
        int rv = ap_proxy_trans_match(r, dconf->alias, dconf);
        if (DONE != rv) {
            return rv;
        }
    }

    conf = (proxy_server_conf *) ap_get_module_config(r->server->module_config,
                                                      &proxy_module);

    /* long way - walk the list of aliases, find a match */
    if (conf->aliases->nelts) {
        ent = (struct proxy_alias *) conf->aliases->elts;
        for (i = 0; i < conf->aliases->nelts; i++) {
            int rv = ap_proxy_trans_match(r, &ent[i], dconf);
            if (DONE != rv) {
                return rv;
            }
        }
    }
    return DECLINED;
}

static int proxy_walk(request_rec *r)
{
    proxy_server_conf *sconf = ap_get_module_config(r->server->module_config,
                                                    &proxy_module);
    ap_conf_vector_t *per_dir_defaults = r->server->lookup_defaults;
    ap_conf_vector_t **sec_proxy = (ap_conf_vector_t **) sconf->sec_proxy->elts;
    ap_conf_vector_t *entry_config;
    proxy_dir_conf *entry_proxy;
    int num_sec = sconf->sec_proxy->nelts;
    /* XXX: shouldn't we use URI here?  Canonicalize it first?
     * Pass over "proxy:" prefix
     */
    const char *proxyname = r->filename + 6;
    int j;
    apr_pool_t *rxpool = NULL;

    for (j = 0; j < num_sec; ++j)
    {
        int nmatch = 0;
        int i;
        ap_regmatch_t *pmatch = NULL;

        entry_config = sec_proxy[j];
        entry_proxy = ap_get_module_config(entry_config, &proxy_module);

        if (entry_proxy->r) {

            if (entry_proxy->refs && entry_proxy->refs->nelts) {
                if (!rxpool) {
                    apr_pool_create(&rxpool, r->pool);
                }
                nmatch = entry_proxy->refs->nelts;
                pmatch = apr_palloc(rxpool, nmatch*sizeof(ap_regmatch_t));
            }

            if (ap_regexec(entry_proxy->r, proxyname, nmatch, pmatch, 0)) {
                continue;
            }

            for (i = 0; i < nmatch; i++) {
                if (pmatch[i].rm_so >= 0 && pmatch[i].rm_eo >= 0 &&
                        ((const char **)entry_proxy->refs->elts)[i]) {
                    apr_table_setn(r->subprocess_env,
                            ((const char **)entry_proxy->refs->elts)[i],
                            apr_pstrndup(r->pool,
                                    proxyname + pmatch[i].rm_so,
                                    pmatch[i].rm_eo - pmatch[i].rm_so));
                }
            }
        }

        else if (
            /* XXX: What about case insensitive matching ???
             * Compare regex, fnmatch or string as appropriate
             * If the entry doesn't relate, then continue
             */
            entry_proxy->p_is_fnmatch ? apr_fnmatch(entry_proxy->p,
                    proxyname, 0) :
                    strncmp(proxyname, entry_proxy->p,
                            strlen(entry_proxy->p))) {
            continue;
        }
        per_dir_defaults = ap_merge_per_dir_configs(r->pool, per_dir_defaults,
                                                             entry_config);
    }

    r->per_dir_config = per_dir_defaults;

    if (rxpool) {
        apr_pool_destroy(rxpool);
    }

    return OK;
}

static int proxy_map_location(request_rec *r)
{
    int access_status;

    if (!r->proxyreq || !r->filename || strncmp(r->filename, "proxy:", 6) != 0)
        return DECLINED;

    /* Don't let the core or mod_http map_to_storage hooks handle this,
     * We don't need directory/file_walk, and we want to TRACE on our own.
     */
    if ((access_status = proxy_walk(r))) {
        ap_die(access_status, r);
        return access_status;
    }

    return OK;
}

/* -------------------------------------------------------------- */
/* Fixup the filename */

/*
 * Canonicalise the URL
 */
static int proxy_fixup(request_rec *r)
{
    char *url, *p;
    int access_status;
    proxy_dir_conf *dconf = ap_get_module_config(r->per_dir_config,
                                                 &proxy_module);

    if (!r->proxyreq || !r->filename || strncmp(r->filename, "proxy:", 6) != 0)
        return DECLINED;

    /* XXX: Shouldn't we try this before we run the proxy_walk? */
    url = &r->filename[6];

    if ((dconf->interpolate_env == 1) && (r->proxyreq == PROXYREQ_REVERSE)) {
        /* create per-request copy of reverse proxy conf,
         * and interpolate vars in it
         */
        proxy_req_conf *rconf = apr_palloc(r->pool, sizeof(proxy_req_conf));
        ap_set_module_config(r->request_config, &proxy_module, rconf);
        rconf->raliases = proxy_vars(r, dconf->raliases);
        rconf->cookie_paths = proxy_vars(r, dconf->cookie_paths);
        rconf->cookie_domains = proxy_vars(r, dconf->cookie_domains);
    }

    /* canonicalise each specific scheme */
    if ((access_status = proxy_run_canon_handler(r, url))) {
        return access_status;
    }

    p = strchr(url, ':');
    if (p == NULL || p == url)
        return HTTP_BAD_REQUEST;

    return OK;      /* otherwise; we've done the best we can */
}
/* Send a redirection if the request contains a hostname which is not */
/* fully qualified, i.e. doesn't have a domain name appended. Some proxy */
/* servers like Netscape's allow this and access hosts from the local */
/* domain in this case. I think it is better to redirect to a FQDN, since */
/* these will later be found in the bookmarks files. */
/* The "ProxyDomain" directive determines what domain will be appended */
static int proxy_needsdomain(request_rec *r, const char *url, const char *domain)
{
    char *nuri;
    const char *ref;

    /* We only want to worry about GETs */
    if (!r->proxyreq || r->method_number != M_GET || !r->parsed_uri.hostname)
        return DECLINED;

    /* If host does contain a dot already, or it is "localhost", decline */
    if (strchr(r->parsed_uri.hostname, '.') != NULL /* has domain, or IPv4 literal */
     || strchr(r->parsed_uri.hostname, ':') != NULL /* IPv6 literal */
     || strcasecmp(r->parsed_uri.hostname, "localhost") == 0)
        return DECLINED;    /* host name has a dot already */

    ref = apr_table_get(r->headers_in, "Referer");

    /* Reassemble the request, but insert the domain after the host name */
    /* Note that the domain name always starts with a dot */
    r->parsed_uri.hostname = apr_pstrcat(r->pool, r->parsed_uri.hostname,
                                         domain, NULL);
    nuri = apr_uri_unparse(r->pool,
                           &r->parsed_uri,
                           APR_URI_UNP_REVEALPASSWORD);

    apr_table_setn(r->headers_out, "Location", nuri);
    ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(01138)
                  "Domain missing: %s sent to %s%s%s", r->uri,
                  apr_uri_unparse(r->pool, &r->parsed_uri,
                                  APR_URI_UNP_OMITUSERINFO),
                  ref ? " from " : "", ref ? ref : "");

    return HTTP_MOVED_PERMANENTLY;
}

/* -------------------------------------------------------------- */
/* Invoke handler */

static int proxy_handler(request_rec *r)
{
    char *uri, *scheme, *p;
    const char *p2;
    void *sconf = r->server->module_config;
    proxy_server_conf *conf = (proxy_server_conf *)
        ap_get_module_config(sconf, &proxy_module);
    apr_array_header_t *proxies = conf->proxies;
    struct proxy_remote *ents = (struct proxy_remote *) proxies->elts;
    int i, rc, access_status;
    int direct_connect = 0;
    const char *str;
    apr_int64_t maxfwd;