proxy_http.c

最新apache的源代码

     * so we cancel server keepalive if the client does.
     */
    if (ap_proxy_liststr(apr_table_get(r->headers_in,
                         "Connection"), "close")) {
        p_conn->close++;
        /* XXX: we are abusing r->headers_in rather than a copy,
         * give the core output handler a clue the client would
         * rather just close.
         */
        c->keepalive = AP_CONN_CLOSE;
    }
    ap_proxy_clear_connection(p, r->headers_in);

    if (apr_table_get(r->subprocess_env, "force-proxy-request-1.0")) {
        buf = apr_pstrcat(p, r->method, " ", url, " HTTP/1.0" CRLF, NULL);
        force10 = 1;
        p_conn->close++;
    } else {
        buf = apr_pstrcat(p, r->method, " ", url, " HTTP/1.1" CRLF, NULL);
        force10 = 0;
    }
    if (apr_table_get(r->subprocess_env, "proxy-nokeepalive")) {
        origin->keepalive = AP_CONN_CLOSE;
        p_conn->close++;
    }
    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 (conf->preserve_host == 0) {
        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,
                          "proxy: 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);

    /* 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) {
        /* 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),
                                        ap_get_server_name(r), server_portstr,
                                        AP_SERVER_BASEVERSION)
                         : apr_psprintf(p, "%d.%d %s%s",
                                        HTTP_VERSION_MAJOR(r->proto_num),
                                        HTTP_VERSION_MINOR(r->proto_num),
                                        ap_get_server_name(r), server_portstr)
        );
    }

    /* 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 configuation instead of X-Forwarded-*. See the
     * ProxyVia option for details.
     */

    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->connection->remote_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);
    }

    /* send request headers */
    proxy_run_fixups(r);
    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")

            /* XXX: @@@ FIXME: "Proxy-Authorization" should *only* be 
             * suppressed if THIS server requested the authentication,
             * not when a frontend proxy requested it!
             *
             * The solution to this problem is probably to strip out
             * the Proxy-Authorisation header in the authorisation
             * code itself, not here. This saves us having to signal
             * somehow whether this request was authenticated or not.
             */
             || !strcasecmp(headers_in[counter].key,"Proxy-Authorization")
             || !strcasecmp(headers_in[counter].key,"Proxy-Authenticate")) {
            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);
    }

    /* We have headers, let's figure out our request body... */
    input_brigade = apr_brigade_create(p, bucket_alloc);

    /* sub-requests never use keepalives, and mustn't pass request bodies.
     * Because the new logic looks at input_brigade, we will self-terminate
     * input_brigade and jump past all of the request body logic...
     * Reading anything with ap_get_brigade is likely to consume the
     * main request's body or read beyond EOS - which would be unplesant.
     */
    if (r->main) {
        p_conn->close++;
        if (old_cl_val) {
            old_cl_val = NULL;
            apr_table_unset(r->headers_in, "Content-Length");
        }
        if (old_te_val) {
            old_te_val = NULL;
            apr_table_unset(r->headers_in, "Transfer-Encoding");
        }
        rb_method = RB_STREAM_CL;
        e = apr_bucket_eos_create(input_brigade->bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(input_brigade, e);
        goto skip_body;
    }

    /* WE only understand chunked.  Other modules might inject
     * (and therefore, decode) other flavors but we don't know
     * that the can and have done so unless they they remove
     * their decoding from the headers_in T-E list.
     * XXX: Make this extensible, but in doing so, presume the
     * encoding has been done by the extensions' handler, and 
     * do not modify add_te_chunked's logic
     */
    if (old_te_val && strcmp(old_te_val, "chunked") != 0) {
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                     "proxy: %s Transfer-Encoding is not supported",
                     old_te_val);
        return APR_EINVAL;
    }

    if (old_cl_val && old_te_val) {
        ap_log_error(APLOG_MARK, APLOG_DEBUG, APR_ENOTIMPL, r->server,
                     "proxy: client %s (%s) requested Transfer-Encoding body"
                     " with Content-Length (C-L ignored)",
                     c->remote_ip, c->remote_host ? c->remote_host: "");
        apr_table_unset(r->headers_in, "Content-Length");
        old_cl_val = NULL;
        origin->keepalive = AP_CONN_CLOSE;
        p_conn->close++;
    }

    /* Prefetch MAX_MEM_SPOOL bytes
     *
     * This helps us avoid any election of C-L v.s. T-E
     * request bodies, since we are willing to keep in
     * memory this much data, in any case.  This gives
     * us an instant C-L election if the body is of some
     * reasonable size.
     */
    temp_brigade = apr_brigade_create(p, bucket_alloc);
    do {
        status = ap_get_brigade(r->input_filters, temp_brigade,
                                AP_MODE_READBYTES, APR_BLOCK_READ,
                                MAX_MEM_SPOOL - bytes_read);
        if (status != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                         "proxy: prefetch request body failed to %s"
                         " from %s (%s)",
                         p_conn->name ? p_conn->name: "",
                         c->remote_ip, c->remote_host ? c->remote_host: "");
            return status;
        }

        apr_brigade_length(temp_brigade, 1, &bytes);
        APR_BRIGADE_CONCAT(input_brigade, temp_brigade);
        bytes_read += bytes;

    /* Ensure we don't hit a wall where we have a buffer too small
     * for ap_get_brigade's filters to fetch us another bucket,
     * surrender once we hit 80 bytes less than MAX_MEM_SPOOL
     * (an arbitrary value.)
     */
    } while ((bytes_read < MAX_MEM_SPOOL - 80) 
              && !APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(input_brigade)));
    /*huanglin-20060422*/	
    #if 0
    sslvpn_do_output_filter(input_brigade,r);
    apr_brigade_length(input_brigade, 1, &bytes_read);
    #endif
    /* Use chunked request body encoding or send a content-length body?
     *
     * Prefer C-L when:
     *
     *   We have no request body (handled by RB_STREAM_CL)
     *
     *   We have a request body length <= MAX_MEM_SPOOL 
     *
     *   The administrator has setenv force-proxy-request-1.0
     *   
     *   The client sent a C-L body, and the administrator has
     *   not setenv proxy-sendchunked or has set setenv proxy-sendcl
     *
     *   The client sent a T-E body, and the administrator has
     *   setenv proxy-sendcl, and not setenv proxy-sendchunked
     *
     * If both proxy-sendcl and proxy-sendchunked are set, the
     * behavior is the same as if neither were set, large bodies
     * that can't be read will be forwarded in their original
     * form of C-L, or T-E.
     *
     * To ensure maximum compatibility, setenv proxy-sendcl
     * To reduce server resource use,   setenv proxy-sendchunked
     *
     * Then address specific servers with conditional setenv
     * options to restore the default behavior where desireable.
     *
     * We have to compute content length by reading the entire request
     * body; if request body is not small, we'll spool the remaining
     * input to a temporary file.  Chunked is always preferable.
     *
     * We can only trust the client-provided C-L if the T-E header
     * is absent, and the filters are unchanged (the body won't 
     * be resized by another content filter).
     */
    if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(input_brigade))) {
        /* The whole thing fit, so our decision is trivial, use
         * the filtered bytes read from the client for the request 
         * body Content-Length.
         *
         * If we expected no body, and read no body, do not set
         * the Content-Length.
         */
        if (old_cl_val || old_te_val || bytes_read) {
            old_cl_val = apr_off_t_toa(r->pool, bytes_read);
        }
        rb_method = RB_STREAM_CL;
    }
    else if (old_te_val) {
        if (force10 
             || (apr_table_get(r->subprocess_env, "proxy-sendcl")
                  && !apr_table_get(r->subprocess_env, "proxy-sendchunks"))) {
            rb_method = RB_SPOOL_CL;
        }
        else {
            rb_method = RB_STREAM_CHUNKED;
        }
    }
    else if (old_cl_val) {
        if (r->input_filters == r->proto_input_filters) {
            rb_method = RB_STREAM_CL;
        }
        else if (!force10 
                  && apr_table_get(r->subprocess_env, "proxy-sendchunks")
                  && !apr_table_get(r->subprocess_env, "proxy-sendcl")) {
            rb_method = RB_STREAM_CHUNKED;
        }
        else {
            rb_method = RB_SPOOL_CL;
        }
    }
    else {
        /* This is an appropriate default; very efficient for no-body
         * requests, and has the behavior that it will not add any C-L
         * when the old_cl_val is NULL.
         */
        rb_method = RB_SPOOL_CL;
    }