mod_proxy.c

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/* Copyright 1999-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed 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.
 */

#define CORE_PRIVATE

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

/*
 * 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.
 *  type_checker:   set type to PROXY_MAGIC_TYPE if filename begins proxy:
 *  fix_ups:        convert the URL stored in the filename to the
 *                  canonical form.
 *  handler:        handle proxy requests
 */

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

#define PROXY_COPY_CONF_PARAMS(w, c) \
    do {                             \
        (w)->timeout              = (c)->timeout;               \
        (w)->timeout_set          = (c)->timeout_set;           \
        (w)->recv_buffer_size     = (c)->recv_buffer_size;      \
        (w)->recv_buffer_size_set = (c)->recv_buffer_size_set;  \
        (w)->io_buffer_size       = (c)->io_buffer_size;        \
        (w)->io_buffer_size_set   = (c)->io_buffer_size_set;    \
    } while (0)

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

    int ival;
    if (!strcasecmp(key, "loadfactor")) {
        /* Normalized load factor. Used with BalancerMamber,
         * it is a number between 1 and 100.
         */
        worker->lbfactor = atoi(val);
        if (worker->lbfactor < 1 || worker->lbfactor > 100)
            return "LoadFactor must be number between 1..100";
    }
    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 < 1)
            return "Retry must be at least one second";
        worker->retry = apr_time_from_sec(ival);
    }
    else if (!strcasecmp(key, "ttl")) {
        /* Time in seconds that will destroy all the connections
         * that exced the smax
         */
        ival = atoi(val);
        if (ival < 1)
            return "TTL must be at least one second";
        worker->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->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->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->smax = ival;
    }
    else if (!strcasecmp(key, "acquire")) {
        /* Acquire timeout in milliseconds.
         * If set this will be the maximum time to
         * wait for a free connection.
         */
        ival = atoi(val);
        if (ival < 1)
            return "Acquire must be at least one mili second";
        worker->acquire = apr_time_make(0, ival * 1000);
        worker->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->timeout = apr_time_from_sec(ival);
        worker->timeout_set = 1;
    }
    else if (!strcasecmp(key, "iobuffersize")) {
        long s = atol(val);
        worker->io_buffer_size = ((s > AP_IOBUFSIZE) ? s : AP_IOBUFSIZE);
        worker->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->recv_buffer_size = ival;
        worker->recv_buffer_size_set = 1;
    }
    else if (!strcasecmp(key, "keepalive")) {
        if (!strcasecmp(val, "on"))
            worker->keepalive = 1;
        else if (!strcasecmp(val, "off"))
            worker->keepalive = 0;
        else
            return "KeepAlive must be On|Off";
        worker->keepalive_set = 1;
    }
    else if (!strcasecmp(key, "route")) {
        /* Worker route.
         */
        if (strlen(val) > PROXY_WORKER_MAX_ROUTE_SIZ)
            return "Route length must be < 64 characters";
        worker->route = apr_pstrdup(p, val);
    }
    else if (!strcasecmp(key, "redirect")) {
        /* Worker redirection route.
         */
        if (strlen(val) > PROXY_WORKER_MAX_ROUTE_SIZ)
            return "Redirect length must be < 64 characters";
        worker->redirect = apr_pstrdup(p, val);
    }
    else if (!strcasecmp(key, "status")) {
        const char *v;
        int mode = 1;
        /* Worker status.
         */
        for (v = val; *v; v++) {
            if (*v == '+') {
                mode = 1;
                v++;
            }
            else if (*v == '-') {
                mode = 0;
                v++;
            }
            if (*v == 'D' || *v == 'd') {
                if (mode)
                    worker->status |= PROXY_WORKER_DISABLED;
                else
                    worker->status &= ~PROXY_WORKER_DISABLED;
            }
            else if (*v == 'S' || *v == 's') {
                if (mode)
                    worker->status |= PROXY_WORKER_STOPPED;
                else
                    worker->status &= ~PROXY_WORKER_STOPPED;
            }
            else if (*v == 'E' || *v == 'e') {
                if (mode)
                    worker->status |= PROXY_WORKER_IN_ERROR;
                else
                    worker->status &= ~PROXY_WORKER_IN_ERROR;
            }
            else {
                return "Unknow status parameter option";
            }
        }
    }
    else if (!strcasecmp(key, "flushpackets")) {
        if (!strcasecmp(val, "on"))
            worker->flush_packets = flush_on;
        else if (!strcasecmp(val, "off"))
            worker->flush_packets = flush_off;
        else if (!strcasecmp(val, "auto"))
            worker->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->flush_wait = PROXY_FLUSH_WAIT;
        else
            worker->flush_wait = ival * 1000;    /* change to microseconds */
    }
    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")) {
        /* Balancer sticky session name.
         * Set to something like JSESSIONID or
         * PHPSESSIONID, etc..,
         */
        balancer->sticky = apr_pstrdup(p, 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->sticky_force = 1;
        else if (!strcasecmp(val, "off"))
            balancer->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->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->max_attempts = ival;
        balancer->max_attempts_set = 1;
    }
    else if (!strcasecmp(key, "lbmethod")) {
        proxy_balancer_method *provider;
        provider = ap_lookup_provider(PROXY_LBMETHOD, val, "0");
        if (provider) {
            balancer->lbmethod = provider;
            return NULL;
        }
        return "unknown lbmethod";
    }
    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.
 */