mod_proxy_ajp.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

/* 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.
 */

/* AJP routines for Apache proxy */

#include "mod_proxy.h"
#include "ajp.h"

module AP_MODULE_DECLARE_DATA proxy_ajp_module;

/*
 * Canonicalise http-like URLs.
 * scheme is the scheme for the URL
 * url is the URL starting with the first '/'
 * def_port is the default port for this scheme.
 */
static int proxy_ajp_canon(request_rec *r, char *url)
{
    char *host, *path, sport[7];
    char *search = NULL;
    const char *err;
    apr_port_t port = AJP13_DEF_PORT;

    /* ap_port_of_scheme() */
    if (strncasecmp(url, "ajp:", 4) == 0) {
        url += 4;
    }
    else {
        return DECLINED;
    }

    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
             "proxy: AJP: canonicalising URL %s", url);

    /*
     * do syntactic check.
     * We break the URL into host, port, path, search
     */
    err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
    if (err) {
        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                      "error parsing URL %s: %s",
                      url, err);
        return HTTP_BAD_REQUEST;
    }

    /*
     * now parse path/search args, according to rfc1738:
     * process the path. With proxy-noncanon set (by
     * mod_proxy) we use the raw, unparsed uri
     */
    if (apr_table_get(r->notes, "proxy-nocanon")) {
        path = url;   /* this is the raw path */
    }
    else {
        path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
                                 r->proxyreq);
        search = r->args;
    }
    if (path == NULL)
        return HTTP_BAD_REQUEST;

    apr_snprintf(sport, sizeof(sport), ":%d", port);

    if (ap_strchr_c(host, ':')) {
        /* if literal IPv6 address */
        host = apr_pstrcat(r->pool, "[", host, "]", NULL);
    }
    r->filename = apr_pstrcat(r->pool, "proxy:ajp://", host, sport,
                              "/", path, (search) ? "?" : "",
                              (search) ? search : "", NULL);
    return OK;
}

#define METHOD_NON_IDEMPOTENT       0
#define METHOD_IDEMPOTENT           1
#define METHOD_IDEMPOTENT_WITH_ARGS 2

static int is_idempotent(request_rec *r)
{
    /*
     * RFC2616 (9.1.2): GET, HEAD, PUT, DELETE, OPTIONS, TRACE are considered
     * idempotent. Hint: HEAD requests use M_GET as method number as well.
     */
    switch (r->method_number) {
        case M_GET:
        case M_DELETE:
        case M_PUT:
        case M_OPTIONS:
        case M_TRACE:
            /*
             * If the request has arguments it might have side-effects and thus
             * it might be undesirable to resent it to a backend again
             * automatically.
             */
            if (r->args) {
                return METHOD_IDEMPOTENT_WITH_ARGS;
            }
            return METHOD_IDEMPOTENT;
        /* Everything else is not considered idempotent. */
        default:
            return METHOD_NON_IDEMPOTENT;
    }
}

static apr_off_t get_content_length(request_rec * r)
{
    apr_off_t len = 0;

    if (r->clength > 0) {
        return r->clength;
    }
    else if (r->main == NULL) {
        const char *clp = apr_table_get(r->headers_in, "Content-Length");

        if (clp) {
            char *errp;
            if (apr_strtoff(&len, clp, &errp, 10) || *errp || len < 0) {
                len = 0; /* parse error */
            }
        }
    }

    return len;
}

/*
 * XXX: AJP Auto Flushing
 *
 * When processing CMD_AJP13_SEND_BODY_CHUNK AJP messages we will do a poll
 * with FLUSH_WAIT miliseconds timeout to determine if more data is currently
 * available at the backend. If there is no more data available, we flush
 * the data to the client by adding a flush bucket to the brigade we pass
 * up the filter chain.
 * This is only a bandaid to fix the AJP/1.3 protocol shortcoming of not
 * sending (actually not having defined) a flush message, when the data
 * should be flushed to the client. As soon as this protocol shortcoming is
 * fixed this code should be removed.
 *
 * For further discussion see PR37100.
 * http://issues.apache.org/bugzilla/show_bug.cgi?id=37100
 */

/*
 * process the request and write the response.
 */
static int ap_proxy_ajp_request(apr_pool_t *p, request_rec *r,
                                proxy_conn_rec *conn,
                                conn_rec *origin,
                                proxy_dir_conf *conf,
                                apr_uri_t *uri,
                                char *url, char *server_portstr)
{
    apr_status_t status;
    int result;
    apr_bucket *e;
    apr_bucket_brigade *input_brigade;
    apr_bucket_brigade *output_brigade;
    ajp_msg_t *msg;
    apr_size_t bufsiz = 0;
    char *buff;
    char *send_body_chunk_buff;
    apr_uint16_t size;
    const char *tenc;
    int havebody = 1;
    int output_failed = 0;
    int backend_failed = 0;
    apr_off_t bb_len;
    int data_sent = 0;
    int headers_sent = 0;
    int rv = 0;
    apr_int32_t conn_poll_fd;
    apr_pollfd_t *conn_poll;
    proxy_server_conf *psf =
    ap_get_module_config(r->server->module_config, &proxy_module);
    apr_size_t maxsize = AJP_MSG_BUFFER_SZ;
    int send_body = 0;
    apr_off_t content_length = 0;

    if (psf->io_buffer_size_set)
       maxsize = psf->io_buffer_size;
    if (maxsize > AJP_MAX_BUFFER_SZ)
       maxsize = AJP_MAX_BUFFER_SZ;
    else if (maxsize < AJP_MSG_BUFFER_SZ)
       maxsize = AJP_MSG_BUFFER_SZ;
    maxsize = APR_ALIGN(maxsize, 1024);
       
    /*
     * Send the AJP request to the remote server
     */

    /* send request headers */
    status = ajp_send_header(conn->sock, r, maxsize, uri);
    if (status != APR_SUCCESS) {
        conn->close++;
        ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                     "proxy: AJP: request failed to %pI (%s)",
                     conn->worker->cp->addr,
                     conn->worker->hostname);
        if (status == AJP_EOVERFLOW)
            return HTTP_BAD_REQUEST;
        else {
            /*
             * This is only non fatal when the method is idempotent. In this
             * case we can dare to retry it with a different worker if we are
             * a balancer member.
             */
            if (is_idempotent(r) == METHOD_IDEMPOTENT) {
                return HTTP_SERVICE_UNAVAILABLE;
            }
            return HTTP_INTERNAL_SERVER_ERROR;
        }
    }

    /* allocate an AJP message to store the data of the buckets */
    bufsiz = maxsize;
    status = ajp_alloc_data_msg(r->pool, &buff, &bufsiz, &msg);
    if (status != APR_SUCCESS) {
        /* We had a failure: Close connection to backend */
        conn->close++;
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "proxy: ajp_alloc_data_msg failed");
        return HTTP_INTERNAL_SERVER_ERROR;
    }

    /* read the first bloc of data */
    input_brigade = apr_brigade_create(p, r->connection->bucket_alloc);
    tenc = apr_table_get(r->headers_in, "Transfer-Encoding");
    if (tenc && (strcasecmp(tenc, "chunked") == 0)) {
        /* The AJP protocol does not want body data yet */
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "proxy: request is chunked");
    } else {
        /* Get client provided Content-Length header */
        content_length = get_content_length(r);
        status = ap_get_brigade(r->input_filters, input_brigade,
                                AP_MODE_READBYTES, APR_BLOCK_READ,
                                maxsize - AJP_HEADER_SZ);

        if (status != APR_SUCCESS) {
            /* We had a failure: Close connection to backend */
            conn->close++;
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "proxy: ap_get_brigade failed");
            apr_brigade_destroy(input_brigade);
            return HTTP_INTERNAL_SERVER_ERROR;
        }

        /* have something */
        if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(input_brigade))) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                         "proxy: APR_BUCKET_IS_EOS");
        }

        /* Try to send something */
        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "proxy: data to read (max %" APR_SIZE_T_FMT
                     " at %" APR_SIZE_T_FMT ")", bufsiz, msg->pos);

        status = apr_brigade_flatten(input_brigade, buff, &bufsiz);
        if (status != APR_SUCCESS) {
            /* We had a failure: Close connection to backend */
            conn->close++;
            apr_brigade_destroy(input_brigade);
            ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                         "proxy: apr_brigade_flatten");
            return HTTP_INTERNAL_SERVER_ERROR;
        }
        apr_brigade_cleanup(input_brigade);

        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                     "proxy: got %" APR_SIZE_T_FMT " bytes of data", bufsiz);
        if (bufsiz > 0) {
            status = ajp_send_data_msg(conn->sock, msg, bufsiz);
            if (status != APR_SUCCESS) {
                /* We had a failure: Close connection to backend */
                conn->close++;
                apr_brigade_destroy(input_brigade);
                ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                             "proxy: send failed to %pI (%s)",
                             conn->worker->cp->addr,
                             conn->worker->hostname);
                /*
                 * It is fatal when we failed to send a (part) of the request
                 * body.
                 */
                return HTTP_INTERNAL_SERVER_ERROR;
            }
            conn->worker->s->transferred += bufsiz;
            send_body = 1;
        }
        else if (content_length > 0) {
            ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                         "proxy: read zero bytes, expecting"
                         " %" APR_OFF_T_FMT " bytes",
                         content_length);
            status = ajp_send_data_msg(conn->sock, msg, 0);
            if (status != APR_SUCCESS) {
                /* We had a failure: Close connection to backend */
                conn->close++;
                ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                            "proxy: send failed to %pI (%s)",
                            conn->worker->cp->addr,
                            conn->worker->hostname);
                return HTTP_INTERNAL_SERVER_ERROR;
            }
            else {
                /* Client send zero bytes with C-L > 0
                 */
                return HTTP_BAD_REQUEST;
            }
        }
    }

    /* read the response */
    conn->data = NULL;
    status = ajp_read_header(conn->sock, r, maxsize,
                             (ajp_msg_t **)&(conn->data));
    if (status != APR_SUCCESS) {
        /* We had a failure: Close connection to backend */
        conn->close++;
        apr_brigade_destroy(input_brigade);
        ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                     "proxy: read response failed from %pI (%s)",
                     conn->worker->cp->addr,
                     conn->worker->hostname);
        /*
         * This is only non fatal when we have not sent (parts) of a possible
         * request body so far (we do not store it and thus cannot sent it
         * again) and the method is idempotent. In this case we can dare to
         * retry it with a different worker if we are a balancer member.
         */
        if (!send_body && (is_idempotent(r) == METHOD_IDEMPOTENT)) {
            return HTTP_SERVICE_UNAVAILABLE;
        }
        return HTTP_INTERNAL_SERVER_ERROR;
    }
    /* parse the reponse */
    result = ajp_parse_type(r, conn->data);
    output_brigade = apr_brigade_create(p, r->connection->bucket_alloc);

    /*
     * Prepare apr_pollfd_t struct for possible later check if there is currently
     * data available from the backend (do not flush response to client)