mod_proxy_http.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.
 */

/* HTTP routines for Apache proxy */

#include "mod_proxy.h"
#include "ap_regex.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, sport[7];
    char *search = NULL;
    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:
     * process the path.
     *
     * In a reverse proxy, our URL has been processed, so canonicalise
     * unless proxy-nocanon is set to say it's raw
     * In a forward proxy, we have and MUST NOT MANGLE the original.
     */
    switch (r->proxyreq) {
    default: /* wtf are we doing here? */
    case PROXYREQ_REVERSE:
        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;
        }
        break;
    case PROXYREQ_PROXY:
        path = url;
        break;
    }

    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 */
typedef struct header_dptr {
    apr_pool_t *pool;
    apr_table_t *table;
    apr_time_t time;
} header_dptr;
static ap_regex_t *warn_rx;
static int clean_warning_headers(void *data, const char *key, const char *val)
{
    apr_table_t *headers = ((header_dptr*)data)->table;
    apr_pool_t *pool = ((header_dptr*)data)->pool;
    char *warning;
    char *date;
    apr_time_t warn_time;
    const int nmatch = 3;
    ap_regmatch_t pmatch[3];

    if (headers == NULL) {
        ((header_dptr*)data)->table = headers = apr_table_make(pool, 2);
    }
/*
 * Parse this, suckers!
 *
 *    Warning    = "Warning" ":" 1#warning-value
 *
 *    warning-value = warn-code SP warn-agent SP warn-text
 *                                             [SP warn-date]
 *
 *    warn-code  = 3DIGIT
 *    warn-agent = ( host [ ":" port ] ) | pseudonym
 *                    ; the name or pseudonym of the server adding
 *                    ; the Warning header, for use in debugging
 *    warn-text  = quoted-string
 *    warn-date  = <"> HTTP-date <">
 *
 * Buggrit, use a bloomin' regexp!
 * (\d{3}\s+\S+\s+\".*?\"(\s+\"(.*?)\")?)  --> whole in $1, date in $3
 */
    while (!ap_regexec(warn_rx, val, nmatch, pmatch, 0)) {
        warning = apr_pstrndup(pool, val+pmatch[0].rm_so,
                               pmatch[0].rm_eo - pmatch[0].rm_so);
        warn_time = 0;
        if (pmatch[2].rm_eo > pmatch[2].rm_so) {
            /* OK, we have a date here */
            date = apr_pstrndup(pool, val+pmatch[2].rm_so,
                                pmatch[2].rm_eo - pmatch[2].rm_so);
            warn_time = apr_date_parse_http(date);
        }
        if (!warn_time || (warn_time == ((header_dptr*)data)->time)) {
            apr_table_addn(headers, key, warning);
        }
        val += pmatch[0].rm_eo;
    }
    return 1;
}
static apr_table_t *ap_proxy_clean_warnings(apr_pool_t *p, apr_table_t *headers)
{
   header_dptr x;
   x.pool = p;
   x.table = NULL;
   x.time = apr_date_parse_http(apr_table_get(headers, "Date"));
   apr_table_do(clean_warning_headers, &x, headers, "Warning", NULL);
   if (x.table != NULL) {
       apr_table_unset(headers, "Warning");
       return apr_table_overlay(p, headers, x.table);
   }
   else {
        return headers;
   }
}
static int clear_conn_headers(void *data, const char *key, const char *val)
{
    apr_table_t *headers = ((header_dptr*)data)->table;
    apr_pool_t *pool = ((header_dptr*)data)->pool;
    const char *name;
    char *next = apr_pstrdup(pool, val);
    while (*next) {
        name = next;
        while (*next && !apr_isspace(*next) && (*next != ',')) {
            ++next;
        }
        while (*next && (apr_isspace(*next) || (*next == ','))) {
            *next++ = '\0';
        }
        apr_table_unset(headers, name);
    }
    return 1;
}
static void ap_proxy_clear_connection(apr_pool_t *p, apr_table_t *headers)
{
    header_dptr x;
    x.pool = p;
    x.table = headers;
    apr_table_unset(headers, "Proxy-Connection");
    apr_table_do(clear_conn_headers, &x, headers, "Connection", NULL);
    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 int 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);
        if (origin->aborted) { 
            return APR_STATUS_IS_TIMEUP(status) ? HTTP_GATEWAY_TIME_OUT : HTTP_BAD_GATEWAY;
        }
        else { 
            return HTTP_BAD_REQUEST; 
        }
    }
    apr_brigade_cleanup(bb);
    return OK;
}

#define MAX_MEM_SPOOL 16384

static int 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, rv = OK;
    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