mod_proxy_http.c

apache服务器源代码（版本号：2.2.2）

/* 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.
 */

/* HTTP routines for Apache proxy */

#include "mod_proxy.h"

module AP_MODULE_DECLARE_DATA proxy_http_module;

static apr_status_t ap_proxy_http_cleanup(const char *scheme,
                                          request_rec *r,
                                          proxy_conn_rec *backend);

/*
 * 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_http_canon(request_rec *r, char *url)
{
    char *host, *path, *search, sport[7];
    const char *err;
    const char *scheme;
    apr_port_t port, def_port;

    /* ap_port_of_scheme() */
    if (strncasecmp(url, "http:", 5) == 0) {
        url += 5;
        scheme = "http";
    }
    else if (strncasecmp(url, "https:", 6) == 0) {
        url += 6;
        scheme = "https";
    }
    else {
        return DECLINED;
    }
    def_port = apr_uri_port_of_scheme(scheme);

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

    /* do syntatic check.
     * We break the URL into host, port, path, search
     */
    port = def_port;
    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 */
    /* N.B. if this isn't a true proxy request, then the URL _path_
     * has already been decoded.  True proxy requests have r->uri
     * == r->unparsed_uri, and no others have that property.
     */
    if (r->uri == r->unparsed_uri) {
        search = strchr(url, '?');
        if (search != NULL)
            *(search++) = '\0';
    }
    else
        search = r->args;

    /* process path */
    path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0, r->proxyreq);
    if (path == NULL)
        return HTTP_BAD_REQUEST;

    if (port != def_port)
        apr_snprintf(sport, sizeof(sport), ":%d", port);
    else
        sport[0] = '\0';

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

/* Clear all connection-based headers from the incoming headers table */
static void ap_proxy_clear_connection(apr_pool_t *p, apr_table_t *headers)
{
    const char *name;
    char *next = apr_pstrdup(p, apr_table_get(headers, "Connection"));

    apr_table_unset(headers, "Proxy-Connection");
    if (!next)
        return;

    while (*next) {
        name = next;
        while (*next && !apr_isspace(*next) && (*next != ',')) {
            ++next;
        }
        while (*next && (apr_isspace(*next) || (*next == ','))) {
            *next = '\0';
            ++next;
        }
        apr_table_unset(headers, name);
    }
    apr_table_unset(headers, "Connection");
}

static void add_te_chunked(apr_pool_t *p,
                           apr_bucket_alloc_t *bucket_alloc,
                           apr_bucket_brigade *header_brigade)
{
    apr_bucket *e;
    char *buf;
    const char te_hdr[] = "Transfer-Encoding: chunked" CRLF;

    buf = apr_pmemdup(p, te_hdr, sizeof(te_hdr)-1);
    ap_xlate_proto_to_ascii(buf, sizeof(te_hdr)-1);

    e = apr_bucket_pool_create(buf, sizeof(te_hdr)-1, p, bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}

static void add_cl(apr_pool_t *p,
                   apr_bucket_alloc_t *bucket_alloc,
                   apr_bucket_brigade *header_brigade,
                   const char *cl_val)
{
    apr_bucket *e;
    char *buf;

    buf = apr_pstrcat(p, "Content-Length: ",
                      cl_val,
                      CRLF,
                      NULL);
    ap_xlate_proto_to_ascii(buf, strlen(buf));
    e = apr_bucket_pool_create(buf, strlen(buf), p, bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}

#define ASCII_CRLF  "\015\012"
#define ASCII_ZERO  "\060"

static void terminate_headers(apr_bucket_alloc_t *bucket_alloc,
                              apr_bucket_brigade *header_brigade)
{
    apr_bucket *e;

    /* add empty line at the end of the headers */
    e = apr_bucket_immortal_create(ASCII_CRLF, 2, bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(header_brigade, e);
}

static apr_status_t pass_brigade(apr_bucket_alloc_t *bucket_alloc,
                                 request_rec *r, proxy_conn_rec *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)
        conn->worker->s->transferred += transferred;
    status = ap_pass_brigade(origin->output_filters, bb);
    if (status != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
                     "proxy: pass request body failed to %pI (%s)",
                     conn->addr, conn->hostname);
        return status;
    }
    apr_brigade_cleanup(bb);
    return APR_SUCCESS;
}

#define MAX_MEM_SPOOL 16384

static apr_status_t stream_reqbody_chunked(apr_pool_t *p,
                                           request_rec *r,
                                           proxy_conn_rec *p_conn,
                                           conn_rec *origin,
                                           apr_bucket_brigade *header_brigade,
                                           apr_bucket_brigade *input_brigade)
{
    int seen_eos = 0;
    apr_size_t hdr_len;
    apr_off_t bytes;
    apr_status_t status;
    apr_bucket_alloc_t *bucket_alloc = r->connection->bucket_alloc;
    apr_bucket_brigade *bb;
    apr_bucket *e;

    add_te_chunked(p, bucket_alloc, header_brigade);
    terminate_headers(bucket_alloc, header_brigade);

    while (!APR_BUCKET_IS_EOS(APR_BRIGADE_FIRST(input_brigade)))
    {
        char chunk_hdr[20];  /* must be here due to transient bucket. */

        /* If this brigade contains EOS, either stop or remove it. */
        if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(input_brigade))) {
            seen_eos = 1;

            /* We can't pass this EOS to the output_filters. */
            e = APR_BRIGADE_LAST(input_brigade);
            apr_bucket_delete(e);
        }

        apr_brigade_length(input_brigade, 1, &bytes);

        hdr_len = apr_snprintf(chunk_hdr, sizeof(chunk_hdr),
                               "%" APR_UINT64_T_HEX_FMT CRLF,
                               (apr_uint64_t)bytes);

        ap_xlate_proto_to_ascii(chunk_hdr, hdr_len);
        e = apr_bucket_transient_create(chunk_hdr, hdr_len,
                                        bucket_alloc);
        APR_BRIGADE_INSERT_HEAD(input_brigade, e);

        /*
         * Append the end-of-chunk CRLF
         */
        e = apr_bucket_immortal_create(ASCII_CRLF, 2, bucket_alloc);
        APR_BRIGADE_INSERT_TAIL(input_brigade, e);

        if (header_brigade) {
            /* we never sent the header brigade, so go ahead and
             * take care of that now
             */
            bb = header_brigade;

            /*
             * Save input_brigade in bb brigade. (At least) in the SSL case
             * input_brigade contains transient buckets whose data would get
             * overwritten during the next call of ap_get_brigade in the loop.
             * ap_save_brigade ensures these buckets to be set aside.
             * Calling ap_save_brigade with NULL as filter is OK, because
             * bb brigade already has been created and does not need to get
             * created by ap_save_brigade.
             */
            status = ap_save_brigade(NULL, &bb, &input_brigade, p);
            if (status != APR_SUCCESS) {
                return status;
            }

            header_brigade = NULL;
        }
        else {
            bb = input_brigade;
        }

        /* The request is flushed below this loop with chunk EOS header */
        status = pass_brigade(bucket_alloc, r, p_conn, origin, bb, 0);
        if (status != APR_SUCCESS) {
            return status;
        }

        if (seen_eos) {
            break;
        }

        status = ap_get_brigade(r->input_filters, input_brigade,
                                AP_MODE_READBYTES, APR_BLOCK_READ,
                                HUGE_STRING_LEN);

        if (status != APR_SUCCESS) {
            return status;
        }
    }

    if (header_brigade) {
        /* we never sent the header brigade because there was no request body;
         * send it now
         */
        bb = header_brigade;
    }
    else {
        if (!APR_BRIGADE_EMPTY(input_brigade)) {
            /* input brigade still has an EOS which we can't pass to the output_filters. */
            e = APR_BRIGADE_LAST(input_brigade);
            AP_DEBUG_ASSERT(APR_BUCKET_IS_EOS(e));
            apr_bucket_delete(e);
        }
        bb = input_brigade;
    }

    e = apr_bucket_immortal_create(ASCII_ZERO ASCII_CRLF
                                   /* <trailers> */
                                   ASCII_CRLF,
                                   5, bucket_alloc);
    APR_BRIGADE_INSERT_TAIL(bb, e);

    /* Now we have headers-only, or the chunk EOS mark; flush it */
    status = pass_brigade(bucket_alloc, r, p_conn, origin, bb, 1);
    return status;
}

static apr_status_t stream_reqbody_cl(apr_pool_t *p,
                                      request_rec *r,
                                      proxy_conn_rec *p_conn,
                                      conn_rec *origin,
                                      apr_bucket_brigade *header_brigade,
                                      apr_bucket_brigade *input_brigade,
                                      const char *old_cl_val)
{
    int seen_eos = 0;
    apr_status_t status = APR_SUCCESS;
    apr_bucket_alloc_t *bucket_alloc = r->connection->bucket_alloc;
    apr_bucket_brigade *bb;
    apr_bucket *e;
    apr_off_t cl_val = 0;
    apr_off_t bytes;
    apr_off_t bytes_streamed = 0;

    if (old_cl_val) {
        add_cl(p, bucket_alloc, header_brigade, old_cl_val);