proxy_util.c

                                              proxy_conn_rec *conn,
                                              conn_rec *c,
                                              server_rec *s)
{
    apr_sockaddr_t *backend_addr = conn->addr;
    int rc;
    apr_interval_time_t current_timeout;
    apr_bucket_alloc_t *bucket_alloc;

    if (conn->connection) {
        return OK;
    }

    bucket_alloc = apr_bucket_alloc_create(conn->scpool);
    conn->tmp_bb = apr_brigade_create(conn->scpool, bucket_alloc);
    /*
     * The socket is now open, create a new backend server connection
     */
    conn->connection = ap_run_create_connection(conn->scpool, s, conn->sock,
                                                0, NULL,
                                                bucket_alloc);

    if (!conn->connection) {
        /*
         * the peer reset the connection already; ap_run_create_connection()
         * closed the socket
         */
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0,
                     s, APLOGNO(00960) "%s: an error occurred creating a "
                     "new connection to %pI (%s)", proxy_function,
                     backend_addr, conn->hostname);
        /* XXX: Will be closed when proxy_conn is closed */
        socket_cleanup(conn);
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* For ssl connection to backend */
    if (conn->is_ssl) {
        if (!ap_proxy_ssl_enable(conn->connection)) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0,
                         s, APLOGNO(00961) "%s: failed to enable ssl support "
                         "for %pI (%s)", proxy_function,
                         backend_addr, conn->hostname);
            return HTTP_INTERNAL_SERVER_ERROR;
        }
    }
    else {
        /* TODO: See if this will break FTP */
        ap_proxy_ssl_disable(conn->connection);
    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00962)
                 "%s: connection complete to %pI (%s)",
                 proxy_function, backend_addr, conn->hostname);

    /*
     * save the timeout of the socket because core_pre_connection
     * will set it to base_server->timeout
     * (core TimeOut directive).
     */
    apr_socket_timeout_get(conn->sock, &current_timeout);
    /* set up the connection filters */
    rc = ap_run_pre_connection(conn->connection, conn->sock);
    if (rc != OK && rc != DONE) {
        conn->connection->aborted = 1;
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00963)
                     "%s: pre_connection setup failed (%d)",
                     proxy_function, rc);
        return rc;
    }
    apr_socket_timeout_set(conn->sock, current_timeout);

    /* Shutdown the connection before closing it (eg. SSL connections
     * need to be close-notify-ed).
     */
    apr_pool_pre_cleanup_register(conn->scpool, conn, connection_shutdown);

    return OK;
}

int ap_proxy_lb_workers(void)
{
    /*
     * Since we can't resize the scoreboard when reconfiguring, we
     * have to impose a limit on the number of workers, we are
     * able to reconfigure to.
     */
    if (!lb_workers_limit)
        lb_workers_limit = proxy_lb_workers + PROXY_DYNAMIC_BALANCER_LIMIT;
    return lb_workers_limit;
}

PROXY_DECLARE(void) ap_proxy_backend_broke(request_rec *r,
                                           apr_bucket_brigade *brigade)
{
    apr_bucket *e;
    conn_rec *c = r->connection;

    r->no_cache = 1;
    /*
     * If this is a subrequest, then prevent also caching of the main
     * request.
     */
    if (r->main)
        r->main->no_cache = 1;
    e = ap_bucket_error_create(HTTP_BAD_GATEWAY, NULL, c->pool,
                               c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(brigade, e);
    e = apr_bucket_eos_create(c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(brigade, e);
}

/*
 * Provide a string hashing function for the proxy.
 * We offer 2 methods: one is the APR model but we
 * also provide our own, based on either FNV or SDBM.
 * The reason is in case we want to use both to ensure no
 * collisions.
 */
PROXY_DECLARE(unsigned int)
ap_proxy_hashfunc(const char *str, proxy_hash_t method)
{
    if (method == PROXY_HASHFUNC_APR) {
        apr_ssize_t slen = strlen(str);
        return apr_hashfunc_default(str, &slen);
    }
    else if (method == PROXY_HASHFUNC_FNV) {
        /* FNV model */
        unsigned int hash;
        const unsigned int fnv_prime = 0x811C9DC5;
        for (hash = 0; *str; str++) {
            hash *= fnv_prime;
            hash ^= (*str);
        }
        return hash;
    }
    else { /* method == PROXY_HASHFUNC_DEFAULT */
        /* SDBM model */
        unsigned int hash;
        for (hash = 0; *str; str++) {
            hash = (*str) + (hash << 6) + (hash << 16) - hash;
        }
        return hash;
    }
}

PROXY_DECLARE(apr_status_t) ap_proxy_set_wstatus(char c, int set, proxy_worker *w)
{
    unsigned int *status = &w->s->status;
    char flag = toupper(c);
    proxy_wstat_t *pwt = proxy_wstat_tbl;
    while (pwt->bit) {
        if (flag == pwt->flag) {
            if (set)
                *status |= pwt->bit;
            else
                *status &= ~(pwt->bit);
            return APR_SUCCESS;
        }
        pwt++;
    }
    return APR_EINVAL;
}

PROXY_DECLARE(char *) ap_proxy_parse_wstatus(apr_pool_t *p, proxy_worker *w)
{
    char *ret = "";
    unsigned int status = w->s->status;
    proxy_wstat_t *pwt = proxy_wstat_tbl;
    while (pwt->bit) {
        if (status & pwt->bit)
            ret = apr_pstrcat(p, ret, pwt->name, NULL);
        pwt++;
    }
    if (!*ret) {
        ret = "??? ";
    }
    if (PROXY_WORKER_IS_USABLE(w))
        ret = apr_pstrcat(p, ret, "Ok ", NULL);
    return ret;
}

PROXY_DECLARE(apr_status_t) ap_proxy_sync_balancer(proxy_balancer *b, server_rec *s,
                                                    proxy_server_conf *conf)
{
    proxy_worker **workers;
    int i;
    int index;
    proxy_worker_shared *shm;
    proxy_balancer_method *lbmethod;
    ap_slotmem_provider_t *storage = b->storage;

    if (b->s->wupdated <= b->wupdated)
        return APR_SUCCESS;
    /* balancer sync */
    lbmethod = ap_lookup_provider(PROXY_LBMETHOD, b->s->lbpname, "0");
    if (lbmethod) {
        b->lbmethod = lbmethod;
    } else {
        ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s, APLOGNO(02433)
                     "Cannot find LB Method: %s", b->s->lbpname);
        return APR_EINVAL;
    }

    /* worker sync */

    /*
     * Look thru the list of workers in shm
     * and see which one(s) we are lacking...
     * again, the cast to unsigned int is safe
     * since our upper limit is always max_workers
     * which is int.
     */
    for (index = 0; index < b->max_workers; index++) {
        int found;
        apr_status_t rv;
        if ((rv = storage->dptr(b->wslot, (unsigned int)index, (void *)&shm)) != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(00965) "worker slotmem_dptr failed");
            return APR_EGENERAL;
        }
        /* account for possible "holes" in the slotmem
         * (eg: slots 0-2 are used, but 3 isn't, but 4-5 is)
         */
        if (!shm->hash.def || !shm->hash.fnv)
            continue;
        found = 0;
        workers = (proxy_worker **)b->workers->elts;
        for (i = 0; i < b->workers->nelts; i++, workers++) {
            proxy_worker *worker = *workers;
            if (worker->hash.def == shm->hash.def && worker->hash.fnv == shm->hash.fnv) {
                found = 1;
                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02402)
                             "re-grabbing shm[%d] (0x%pp) for worker: %s", i, (void *)shm,
                             ap_proxy_worker_name(conf->pool, worker));
                break;
            }
        }
        if (!found) {
            proxy_worker **runtime;
            apr_global_mutex_lock(proxy_mutex);
            runtime = apr_array_push(b->workers);
            *runtime = apr_palloc(conf->pool, sizeof(proxy_worker));
            apr_global_mutex_unlock(proxy_mutex);
            (*runtime)->hash = shm->hash;
            (*runtime)->context = NULL;
            (*runtime)->cp = NULL;
            (*runtime)->balancer = b;
            (*runtime)->s = shm;
            (*runtime)->tmutex = NULL;
            rv = ap_proxy_initialize_worker(*runtime, s, conf->pool);
            if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(00966) "Cannot init worker");
                return rv;
            }
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(02403)
                         "grabbing shm[%d] (0x%pp) for worker: %s", i, (void *)shm,
                         (*runtime)->s->name);
        }
    }
    if (b->s->need_reset) {
        if (b->lbmethod && b->lbmethod->reset)
            b->lbmethod->reset(b, s);
        b->s->need_reset = 0;
    }
    b->wupdated = b->s->wupdated;
    return APR_SUCCESS;
}

PROXY_DECLARE(proxy_worker_shared *) ap_proxy_find_workershm(ap_slotmem_provider_t *storage,
                                                               ap_slotmem_instance_t *slot,
                                                               proxy_worker *worker,
                                                               unsigned int *index)
{
    proxy_worker_shared *shm;
    unsigned int i, limit;
    limit = storage->num_slots(slot);
    for (i = 0; i < limit; i++) {
        if (storage->dptr(slot, i, (void *)&shm) != APR_SUCCESS) {
            return NULL;
        }
        if ((worker->s->hash.def == shm->hash.def) &&
            (worker->s->hash.fnv == shm->hash.fnv)) {
            *index = i;
            return shm;
        }
    }
    return NULL;
}

PROXY_DECLARE(proxy_balancer_shared *) ap_proxy_find_balancershm(ap_slotmem_provider_t *storage,
                                                                 ap_slotmem_instance_t *slot,
                                                                 proxy_balancer *balancer,
                                                                 unsigned int *index)
{
    proxy_balancer_shared *shm;
    unsigned int i, limit;
    limit = storage->num_slots(slot);
    for (i = 0; i < limit; i++) {
        if (storage->dptr(slot, i, (void *)&shm) != APR_SUCCESS) {
            return NULL;
        }
        if ((balancer->s->hash.def == shm->hash.def) &&
            (balancer->s->hash.fnv == shm->hash.fnv)) {
            *index = i;
            return shm;
        }
    }
    return NULL;
}

typedef struct header_connection {
    apr_pool_t *pool;
    apr_array_header_t *array;
    const char *first;
    unsigned int closed:1;
} header_connection;

static int find_conn_headers(void *data, const char *key, const char *val)
{
    header_connection *x = data;
    const char *name;

    do {
        while (*val == ',' || *val == ';') {
            val++;
        }
        name = ap_get_token(x->pool, &val, 0);
        if (!strcasecmp(name, "close")) {
            x->closed = 1;
        }
        if (!x->first) {
            x->first = name;
        }
        else {
            const char **elt;
            if (!x->array) {
                x->array = apr_array_make(x->pool, 4, sizeof(char *));
            }
            elt = apr_array_push(x->array);
            *elt = name;
        }
    } while (*val);

    return 1;
}

/**
 * Remove all headers referred to by the Connection header.
 */
static int ap_proxy_clear_connection(request_rec *r, apr_table_t *headers)
{
    const char **name;
    header_connection x;

    x.pool = r->pool;
    x.array = NULL;
    x.first = NULL;
    x.closed = 0;

    apr_table_unset(headers, "Proxy-Connection");

    apr_table_do(find_conn_headers, &x, headers, "Connection", NULL);
    if (x.first) {
        /* fast path - no memory allocated for one header */
        apr_table_unset(headers, "Connection");
        apr_table_unset(headers, x.first);
    }
    if (x.array) {
        /* two or more headers */
        while ((name = apr_array_pop(x.array))) {
            apr_table_unset(headers, *name);
        }
    }

    return x.closed;
}

PROXY_DECLARE(int) ap_proxy_create_hdrbrgd(apr_pool_t *p,
                                            apr_bucket_brigade *header_brigade,
                                            request_rec *r,
                                            proxy_conn_rec *p_conn,
                                            proxy_worker *worker,
                                            proxy_server_conf *conf,
                                            apr_uri_t *uri,
                                            char *url, char *server_portstr,
                                            char **old_cl_val,
                                            char **old_te_val)
{
    conn_rec *c = r->connection;
    int counter;
    char *buf;
    const apr_array_header_t *headers_in_array;
    const apr_table_entry_t *headers_in;
    apr_table_t *saved_headers_in;
    apr_bucket *e;
    int do_100_continue;
    conn_rec *origin = p_conn->connection;
    proxy_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &proxy_module);

    /*
     * To be compliant, we only use 100-Continue for requests with bodies.
     * We also make sure we won't be talking HTTP/1.0 as well.
     */
    do_100_continue = (worker->s->ping_timeout_set
                       && ap_request_has_body(r)
                       && (PROXYREQ_REVERSE == r->proxyreq)
                       && !(apr_table_get(r->subprocess_env, "force-proxy-request-1.0")));

    if (apr_table_get(r->subprocess_env, "force-proxy-request-1.0")) {
        /*
         * According to RFC 2616 8.2.3 we are not allowed to forward an
         * Expect: 100-continue to an HTTP/1.0 server. Instead we MUST return
         * a HTTP_EXPECTATION_FAILED
         */
        if (r->expecting_100) {
            return HTTP_EXPECTATION_FAILED;
        }
        buf = apr_pstrcat(p, r->method, " ", url, " HTTP/1.0" CRLF, NULL);
        p_conn->close = 1;
    } else {
        buf = apr_pstrcat(p, r->method, " ", url, " HTTP/1.1" CRLF, NULL);
    }
    if (apr_table_get(r->subprocess_env, "proxy-nokeepalive")) {
        origin->keepalive = AP_CONN_CLOSE;
        p_conn->close = 1;
    }
    ap_xlate_proto_to_ascii(buf, strlen(buf));
    e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(header_brigade, e);
    if (dconf->preserve_host == 0) {
        if (ap_strchr_c(uri->hostname, ':')) { /* if literal IPv6 address */
            if (uri->port_str && uri->port != DEFAULT_HTTP_PORT) {
                buf = apr_pstrcat(p, "Host: [", uri->hostname, "]:",
                                  uri->port_str, CRLF, NULL);
            } else {
                buf = apr_pstrcat(p, "Host: [", uri->hostname, "]", CRLF, NULL);
            }
        } else {
            if (uri->port_str && uri->port != DEFAULT_HTTP_PORT) {
                buf = apr_pstrcat(p, "Host: ", uri->hostname, ":",
                                  uri->port_str, CRLF, NULL);
            } else {
                buf = apr_pstrcat(p, "Host: ", uri->hostname, CRLF, NULL);
            }
        }
    }
    else {
        /* don't want to use r->hostname, as the incoming header might have a
         * port attached
         */
        const char* hostname = apr_table_get(r->headers_in,"Host");
        if (!hostname) {
            hostname =  r->server->server_hostname;
            ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(01092)
                          "no HTTP 0.9 request (with no host line) "
                          "on incoming request and preserve host set "
                          "forcing hostname to be %s for uri %s",
                          hostname, r->uri);
        }
        buf = apr_pstrcat(p, "Host: ", hostname, CRLF, NULL);
    }
    ap_xlate_proto_to_ascii(buf, strlen(buf));
    e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(header_brigade, e);

    /*
     * Save the original headers in here and restore them when leaving, since
     * we will apply proxy purpose only modifications (eg. clearing hop-by-hop
     * headers, add Via or X-Forwarded-* or Expect...), whereas the originals
     * will be needed later to prepare the correct response and logging.
     *
     * Note: We need to take r->pool for apr_table_copy as the key / value
     * pairs in r->headers_in have been created out of r->pool and
     * p might be (and actually is) a longer living pool.
     * This would trigger the bad pool ancestry abort in apr_table_copy if
     * apr is compiled with APR_POOL_DEBUG.
     */
    saved_headers_in = r->headers_in;
    r->headers_in = apr_table_copy(r->pool, saved_headers_in);

    /* handle Via */
    if (conf->viaopt == via_block) {
        /* Block all outgoing Via: headers */
        apr_table_unset(r->headers_in, "Via");
    } else if (conf->viaopt != via_off) {
        const char *server_name = ap_get_server_name(r);
        /* If USE_CANONICAL_NAME_OFF was configured for the proxy virtual host,
         * then the server name returned by ap_get_server_name() is the
         * origin server name (which does make too much sense with Via: headers)
         * so we use the proxy vhost's name instead.
         */
        if (server_name == r->hostname)
            server_name = r->server->server_hostname;
        /* Create a "Via:" request header entry and merge it */
        /* Generate outgoing Via: header with/without server comment: */
        apr_table_mergen(r->headers_in, "Via",
                         (conf->viaopt == via_full)
                         ? apr_psprintf(p, "%d.%d %s%s (%s)",
                                        HTTP_VERSION_MAJOR(r->proto_num),
                                        HTTP_VERSION_MINOR(r->proto_num),
                                        server_name, server_portstr,
                                        AP_SERVER_BASEVERSION)
                         : apr_psprintf(p, "%d.%d %s%s",
                                        HTTP_VERSION_MAJOR(r->proto_num),
                                        HTTP_VERSION_MINOR(r->proto_num),
                                        server_name, server_portstr)
                         );
    }

    /* Use HTTP/1.1 100-Continue as quick "HTTP ping" test
     * to backend
     */
    if (do_100_continue) {
        const char *val;

        if (!r->expecting_100) {
            /* Don't forward any "100 Continue" response if the client is
             * not expecting it.
             */
            apr_table_setn(r->subprocess_env, "proxy-interim-response",
                                              "Suppress");
        }

        /* Add the Expect header if not already there. */
        if (((val = apr_table_get(r->headers_in, "Expect")) == NULL)
                || (strcasecmp(val, "100-Continue") != 0 /* fast path */
                    && !ap_find_token(r->pool, val, "100-Continue"))) {
            apr_table_mergen(r->headers_in, "Expect", "100-Continue");
        }
    }

    /* X-Forwarded-*: handling
     *
     * XXX Privacy Note:
     * -----------------
     *
     * These request headers are only really useful when the mod_proxy
     * is used in a reverse proxy configuration, so that useful info
     * about the client can be passed through the reverse proxy and on
     * to the backend server, which may require the information to
     * function properly.
     *
     * In a forward proxy situation, these options are a potential
     * privacy violation, as information about clients behind the proxy
     * are revealed to arbitrary servers out there on the internet.
     *
     * The HTTP/1.1 Via: header is designed for passing client
     * information through proxies to a server, and should be used in
     * a forward proxy configuration instead of X-Forwarded-*. See the
     * ProxyVia option for details.
     */
    if (dconf->add_forwarded_headers) {
        if (PROXYREQ_REVERSE == r->proxyreq) {
            const char *buf;

            /* Add X-Forwarded-For: so that the upstream has a chance to
             * determine, where the original request came from.
             */
            apr_table_mergen(r->headers_in, "X-Forwarded-For",
                             r->useragent_ip);

            /* Add X-Forwarded-Host: so that upstream knows what the
             * original request hostname was.
             */
            if ((buf = apr_table_get(r->headers_in, "Host"))) {
                apr_table_mergen(r->headers_in, "X-Forwarded-Host", buf);
            }

            /* Add X-Forwarded-Server: so that upstream knows what the
             * name of this proxy server is (if there are more than one)
             * XXX: This duplicates Via: - do we strictly need it?
             */
            apr_table_mergen(r->headers_in, "X-Forwarded-Server",
                             r->server->server_hostname);
        }
    }

    proxy_run_fixups(r);
    if (ap_proxy_clear_connection(r, r->headers_in) < 0) {
        return HTTP_BAD_REQUEST;
    }

    /* send request headers */
    headers_in_array = apr_table_elts(r->headers_in);
    headers_in = (const apr_table_entry_t *) headers_in_array->elts;
    for (counter = 0; counter < headers_in_array->nelts; counter++) {
        if (headers_in[counter].key == NULL
            || headers_in[counter].val == NULL

            /* Already sent */
            || !strcasecmp(headers_in[counter].key, "Host")

            /* Clear out hop-by-hop request headers not to send
             * RFC2616 13.5.1 says we should strip these headers
             */
            || !strcasecmp(headers_in[counter].key, "Keep-Alive")
            || !strcasecmp(headers_in[counter].key, "TE")
            || !strcasecmp(headers_in[counter].key, "Trailer")
            || !strcasecmp(headers_in[counter].key, "Upgrade")

            ) {
            continue;
        }
        /* Do we want to strip Proxy-Authorization ?
         * If we haven't used it, then NO
         * If we have used it then MAYBE: RFC2616 says we MAY propagate it.
         * So let's make it configurable by env.
         */
        if (!strcasecmp(headers_in[counter].key,"Proxy-Authorization")) {
            if (r->user != NULL) { /* we've authenticated */
                if (!apr_table_get(r->subprocess_env, "Proxy-Chain-Auth")) {
                    continue;
                }
            }
        }

        /* Skip Transfer-Encoding and Content-Length for now.
         */
        if (!strcasecmp(headers_in[counter].key, "Transfer-Encoding")) {
            *old_te_val = headers_in[counter].val;
            continue;
        }
        if (!strcasecmp(headers_in[counter].key, "Content-Length")) {
            *old_cl_val = headers_in[counter].val;
            continue;
        }

        /* for sub-requests, ignore freshness/expiry headers */
        if (r->main) {
            if (   !strcasecmp(headers_in[counter].key, "If-Match")
                || !strcasecmp(headers_in[counter].key, "If-Modified-Since")
                || !strcasecmp(headers_in[counter].key, "If-Range")
                || !strcasecmp(headers_in[counter].key, "If-Unmodified-Since")
                || !strcasecmp(headers_in[counter].key, "If-None-Match")) {
                continue;
            }
        }

        buf = apr_pstrcat(p, headers_in[counter].key, ": ",
                          headers_in[counter].val, CRLF,
                          NULL);
        ap_xlate_proto_to_ascii(buf, strlen(buf));
        e = apr_bucket_pool_create(buf, strlen(buf), p, c->bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(header_brigade, e);
    }

    /* Restore the original headers in (see comment above),
     * we won't modify them anymore.
     */
    r->headers_in = saved_headers_in;
    return OK;
}

PROXY_DECLARE(int) ap_proxy_pass_brigade(apr_bucket_alloc_t *bucket_alloc,
                                         request_rec *r, proxy_conn_rec *p_conn,
                                         conn_rec *origin, apr_bucket_brigade *bb,
                                         int flush)
{
    apr_status_t status;
    apr_off_t transferred;

    if (flush) {
        apr_bucket *e = apr_bucket_flush_create(bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(bb, e);
    }
    apr_brigade_length(bb, 0, &transferred);
    if (transferred != -1)
        p_conn->worker->s->transferred += transferred;
    status = ap_pass_brigade(origin->output_filters, bb);
    /* Cleanup the brigade now to avoid buckets lifetime
     * issues in case of error returned below. */
    apr_brigade_cleanup(bb);
    if (status != APR_SUCCESS) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01084)
                      "pass request body failed to %pI (%s)",
                      p_conn->addr, p_conn->hostname);
        if (origin->aborted) {
            const char *ssl_note;

            if (((ssl_note = apr_table_get(origin->notes, "SSL_connect_rv"))
                 != NULL) && (strcmp(ssl_note, "err") == 0)) {
                return ap_proxyerror(r, HTTP_INTERNAL_SERVER_ERROR,
                                     "Error during SSL Handshake with"
                                     " remote server");
            }
            return APR_STATUS_IS_TIMEUP(status) ? HTTP_GATEWAY_TIME_OUT : HTTP_BAD_GATEWAY;
        }
        else {
            return HTTP_BAD_REQUEST;
        }
    }
    return OK;
}

/* Fill in unknown schemes from apr_uri_port_of_scheme() */

typedef struct proxy_schemes_t {
    const char *name;
    apr_port_t default_port;
} proxy_schemes_t ;

static proxy_schemes_t pschemes[] =
{
    {"fcgi",     8000},
    {"ajp",      AJP13_DEF_PORT},
    {"scgi",     SCGI_DEF_PORT},
    {"h2c",      DEFAULT_HTTP_PORT},
    {"h2",       DEFAULT_HTTPS_PORT},
    { NULL, 0xFFFF }     /* unknown port */
};

PROXY_DECLARE(apr_port_t) ap_proxy_port_of_scheme(const char *scheme)
{
    if (scheme) {
        apr_port_t port;
        if ((port = apr_uri_port_of_scheme(scheme)) != 0) {
            return port;
        } else {
            proxy_schemes_t *pscheme;
            for (pscheme = pschemes; pscheme->name != NULL; ++pscheme) {
                if (strcasecmp(scheme, pscheme->name) == 0) {
                    return pscheme->default_port;
                }
            }
        }
    }
    return 0;
}

PROXY_DECLARE(apr_status_t) ap_proxy_buckets_lifetime_transform(request_rec *r,
                                                      apr_bucket_brigade *from,
                                                      apr_bucket_brigade *to)
{
    apr_bucket *e;
    apr_bucket *new;
    const char *data;
    apr_size_t bytes;
    apr_status_t rv = APR_SUCCESS;
    apr_bucket_alloc_t *bucket_alloc = to->bucket_alloc;

    apr_brigade_cleanup(to);
    for (e = APR_BRIGADE_FIRST(from);
         e != APR_BRIGADE_SENTINEL(from);
         e = APR_BUCKET_NEXT(e)) {
        if (!APR_BUCKET_IS_METADATA(e)) {
            apr_bucket_read(e, &data, &bytes, APR_BLOCK_READ);
            new = apr_bucket_transient_create(data, bytes, bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(to, new);
        }
        else if (APR_BUCKET_IS_FLUSH(e)) {
            new = apr_bucket_flush_create(bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(to, new);
        }
        else if (APR_BUCKET_IS_EOS(e)) {
            new = apr_bucket_eos_create(bucket_alloc);
            APR_BRIGADE_INSERT_TAIL(to, new);
        }
        else {
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(03304)
                          "Unhandled bucket type of type %s in"
                          " ap_proxy_buckets_lifetime_transform", e->type->name);
            rv = APR_EGENERAL;
        }
    }
    return rv;
}

PROXY_DECLARE(apr_status_t) ap_proxy_transfer_between_connections(
                                                       request_rec *r,
                                                       conn_rec *c_i,
                                                       conn_rec *c_o,
                                                       apr_bucket_brigade *bb_i,
                                                       apr_bucket_brigade *bb_o,
                                                       const char *name,
                                                       int *sent,
                                                       apr_off_t bsize,
                                                       int after)
{
    apr_status_t rv;
#ifdef DEBUGGING
    apr_off_t len;
#endif

    do {
        apr_brigade_cleanup(bb_i);
        rv = ap_get_brigade(c_i->input_filters, bb_i, AP_MODE_READBYTES,
                            APR_NONBLOCK_READ, bsize);
        if (rv == APR_SUCCESS) {
            if (c_o->aborted) {
                return APR_EPIPE;
            }
            if (APR_BRIGADE_EMPTY(bb_i)) {
                break;
            }
#ifdef DEBUGGING
            len = -1;
            apr_brigade_length(bb_i, 0, &len);
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(03306)
                          "ap_proxy_transfer_between_connections: "
                          "read %" APR_OFF_T_FMT
                          " bytes from %s", len, name);
#endif
            if (sent) {
                *sent = 1;
            }
            ap_proxy_buckets_lifetime_transform(r, bb_i, bb_o);
            if (!after) {
                apr_bucket *b;

                /*
                 * Do not use ap_fflush here since this would cause the flush
                 * bucket to be sent in a separate brigade afterwards which
                 * causes some filters to set aside the buckets from the first
                 * brigade and process them when the flush arrives in the second
                 * brigade. As set asides of our transformed buckets involve
                 * memory copying we try to avoid this. If we have the flush
                 * bucket in the first brigade they directly process the
                 * buckets without setting them aside.
                 */
                b = apr_bucket_flush_create(bb_o->bucket_alloc);
                APR_BRIGADE_INSERT_TAIL(bb_o, b);
            }
            rv = ap_pass_brigade(c_o->output_filters, bb_o);
            if (rv != APR_SUCCESS) {
                ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(03307)
                              "ap_proxy_transfer_between_connections: "
                              "error on %s - ap_pass_brigade",
                              name);
            }
        } else if (!APR_STATUS_IS_EAGAIN(rv) && !APR_STATUS_IS_EOF(rv)) {
            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(03308)
                          "ap_proxy_transfer_between_connections: "
                          "error on %s - ap_get_brigade",
                          name);
        }
    } while (rv == APR_SUCCESS);

    if (after) {
        ap_fflush(c_o->output_filters, bb_o);
    }

    ap_log_rerror(APLOG_MARK, APLOG_TRACE2, rv, r,
                  "ap_proxy_transfer_between_connections complete");

    if (APR_STATUS_IS_EAGAIN(rv)) {
        rv = APR_SUCCESS;
    }

    return rv;
}

PROXY_DECLARE (const char *) ap_proxy_show_hcmethod(hcmethod_t method)
{
    proxy_hcmethods_t *m = proxy_hcmethods;
    for (; m->name; m++) {
        if (m->method == method) {
            return m->name;
        }
    }
    return "???";
}

void proxy_util_register_hooks(apr_pool_t *p)
{
    APR_REGISTER_OPTIONAL_FN(ap_proxy_retry_worker);
    APR_REGISTER_OPTIONAL_FN(ap_proxy_clear_connection);
}