mod_proxy.c

apache简化版

/* ====================================================================
 * Copyright (c) 1996-1998 The Apache Group.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE APACHE GROUP OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Group and was originally based
 * on public domain software written at the National Center for
 * Supercomputing Applications, University of Illinois, Urbana-Champaign.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 */

#include "mod_proxy.h"

#define CORE_PRIVATE

#include "http_log.h"
#include "http_vhost.h"
#include "http_request.h"

/* Some WWW schemes and their default ports; this is basically /etc/services */
/* This will become global when the protocol abstraction comes */
static struct proxy_services defports[] =
{
    {"http", DEFAULT_HTTP_PORT},
    {"ftp", DEFAULT_FTP_PORT},
    {"https", DEFAULT_HTTPS_PORT},
    {"gopher", DEFAULT_GOPHER_PORT},
    {"nntp", DEFAULT_NNTP_PORT},
    {"wais", DEFAULT_WAIS_PORT},
    {"snews", DEFAULT_SNEWS_PORT},
    {"prospero", DEFAULT_PROSPERO_PORT},
    {NULL, -1}			/* unknown port */
};

/*
 * A Web proxy module. Stages:
 *
 *  translate_name: set filename to proxy:<URL>
 *  type_checker:   set type to PROXY_MAGIC_TYPE if filename begins proxy:
 *  fix_ups:        convert the URL stored in the filename to the
 *                  canonical form.
 *  handler:        handle proxy requests
 */

/* -------------------------------------------------------------- */
/* Translate the URL into a 'filename' */

static int alias_match(const char *uri, const char *alias_fakename)
{
    const char *end_fakename = alias_fakename + strlen(alias_fakename);
    const char *aliasp = alias_fakename, *urip = uri;

    while (aliasp < end_fakename) {
	if (*aliasp == '/') {
	    /* any number of '/' in the alias matches any number in
	     * the supplied URI, but there must be at least one...
	     */
	    if (*urip != '/')
		return 0;

	    while (*aliasp == '/')
		++aliasp;
	    while (*urip == '/')
		++urip;
	}
	else {
	    /* Other characters are compared literally */
	    if (*urip++ != *aliasp++)
		return 0;
	}
    }

    /* Check last alias path component matched all the way */

    if (aliasp[-1] != '/' && *urip != '\0' && *urip != '/')
	return 0;

    /* Return number of characters from URI which matched (may be
     * greater than length of alias, since we may have matched
     * doubled slashes)
     */

    return urip - uri;
}

/* Detect if an absoluteURI should be proxied or not.  Note that we
 * have to do this during this phase because later phases are
 * "short-circuiting"... i.e. translate_names will end when the first
 * module returns OK.  So for example, if the request is something like:
 *
 * GET http://othervhost/cgi-bin/printenv HTTP/1.0
 *
 * mod_alias will notice the /cgi-bin part and ScriptAlias it and
 * short-circuit the proxy... just because of the ordering in the
 * configuration file.
 */
static int proxy_detect(request_rec *r)
{
    void *sconf = r->server->module_config;
    proxy_server_conf *conf;

    conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);

    if (conf->req && r->parsed_uri.scheme) {
	/* but it might be something vhosted */
       if (!(r->parsed_uri.hostname
	    && !strcasecmp(r->parsed_uri.scheme, ap_http_method(r))
	    && ap_matches_request_vhost(r, r->parsed_uri.hostname,
               r->parsed_uri.port_str ? r->parsed_uri.port : ap_default_port(r)))) {
	    r->proxyreq = 1;
	    r->uri = r->unparsed_uri;
	    r->filename = ap_pstrcat(r->pool, "proxy:", r->uri, NULL);
	    r->handler = "proxy-server";
        }
    }
    /* We need special treatment for CONNECT proxying: it has no scheme part */
    else if (conf->req && r->method_number == M_CONNECT
	     && r->parsed_uri.hostname
	     && r->parsed_uri.port_str) {
	    r->proxyreq = 1;
	    r->uri = r->unparsed_uri;
	    r->filename = ap_pstrcat(r->pool, "proxy:", r->uri, NULL);
	    r->handler = "proxy-server";
    }
    return DECLINED;
}

static int proxy_trans(request_rec *r)
{
    void *sconf = r->server->module_config;
    proxy_server_conf *conf =
    (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
    int i, len;
    struct proxy_alias *ent = (struct proxy_alias *) conf->aliases->elts;

    if (r->proxyreq) {
	/* someone has already set up the proxy, it was possibly ourselves
	 * in proxy_detect
	 */
	return OK;
    }

    /* XXX: since r->uri has been manipulated already we're not really
     * compliant with RFC1945 at this point.  But this probably isn't
     * an issue because this is a hybrid proxy/origin server.
     */

    for (i = 0; i < conf->aliases->nelts; i++) {
        len = alias_match(r->uri, ent[i].fake);
	    
       if (len > 0) {
           r->filename = ap_pstrcat(r->pool, "proxy:", ent[i].real,
                                 r->uri + len, NULL);
           r->handler = "proxy-server";
           r->proxyreq = 1;
           return OK;
	}
    }
    return DECLINED;
}

/* -------------------------------------------------------------- */
/* Fixup the filename */

/*
 * Canonicalise the URL
 */
static int proxy_fixup(request_rec *r)
{
    char *url, *p;

    if (!r->proxyreq || strncmp(r->filename, "proxy:", 6) != 0)
	return DECLINED;

    url = &r->filename[6];

/* canonicalise each specific scheme */
    if (strncasecmp(url, "http:", 5) == 0)
	return ap_proxy_http_canon(r, url + 5, "http", DEFAULT_HTTP_PORT);
    else if (strncasecmp(url, "ftp:", 4) == 0)
	return ap_proxy_ftp_canon(r, url + 4);

    p = strchr(url, ':');
    if (p == NULL || p == url)
	return HTTP_BAD_REQUEST;

    return OK;		/* otherwise; we've done the best we can */
}

static void proxy_init(server_rec *r, pool *p)
{
    ap_proxy_garbage_init(r, p);
}



/* Send a redirection if the request contains a hostname which is not */
/* fully qualified, i.e. doesn't have a domain name appended. Some proxy */
/* servers like Netscape's allow this and access hosts from the local */
/* domain in this case. I think it is better to redirect to a FQDN, since */
/* these will later be found in the bookmarks files. */
/* The "ProxyDomain" directive determines what domain will be appended */
static int proxy_needsdomain(request_rec *r, const char *url, const char *domain)
{
    char *nuri;
    const char *ref;

    /* We only want to worry about GETs */
    if (!r->proxyreq || r->method_number != M_GET || !r->parsed_uri.hostname)
	return DECLINED;

    /* If host does contain a dot already, or it is "localhost", decline */
    if (strchr(r->parsed_uri.hostname, '.') != NULL
     || strcasecmp(r->parsed_uri.hostname, "localhost") == 0)
	return DECLINED;	/* host name has a dot already */

    ref = ap_table_get(r->headers_in, "Referer");

    /* Reassemble the request, but insert the domain after the host name */
    /* Note that the domain name always starts with a dot */
    r->parsed_uri.hostname = ap_pstrcat(r->pool, r->parsed_uri.hostname,
				     domain, NULL);
    nuri = ap_unparse_uri_components(r->pool,
				  &r->parsed_uri,
				  UNP_REVEALPASSWORD);

    ap_table_set(r->headers_out, "Location", nuri);
    ap_log_rerror(APLOG_MARK, APLOG_INFO|APLOG_NOERRNO, r,
		"Domain missing: %s sent to %s%s%s", r->uri,
		ap_unparse_uri_components(r->pool, &r->parsed_uri,
		      UNP_OMITUSERINFO),
		ref ? " from " : "", ref ? ref : "");

    return HTTP_MOVED_PERMANENTLY;
}

/* -------------------------------------------------------------- */
/* Invoke handler */

static int proxy_handler(request_rec *r)
{
    char *url, *scheme, *p;
    void *sconf = r->server->module_config;
    proxy_server_conf *conf =
    (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
    array_header *proxies = conf->proxies;
    struct proxy_remote *ents = (struct proxy_remote *) proxies->elts;
    int i, rc;
    cache_req *cr;
    int direct_connect = 0;
    const char *maxfwd_str;

    if (!r->proxyreq || strncmp(r->filename, "proxy:", 6) != 0)
	return DECLINED;

    if (r->method_number == M_TRACE &&
	(maxfwd_str = ap_table_get(r->headers_in, "Max-Forwards")) != NULL) {
	int maxfwd = strtol(maxfwd_str, NULL, 10);
	if (maxfwd < 1) {
	    int access_status;
	    r->proxyreq = 0;
	    if ((access_status = ap_send_http_trace(r)))
		ap_die(access_status, r);
	    else
		ap_finalize_request_protocol(r);
	    return OK;
	}
	ap_table_setn(r->headers_in, "Max-Forwards", 
		      ap_psprintf(r->pool, "%d", (maxfwd > 0) ? maxfwd-1 : 0));
    }

    if ((rc = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)))
	return rc;

    url = r->filename + 6;
    p = strchr(url, ':');
    if (p == NULL)
	return HTTP_BAD_REQUEST;

    rc = ap_proxy_cache_check(r, url, &conf->cache, &cr);
    if (rc != DECLINED)
	return rc;

    /* If the host doesn't have a domain name, add one and redirect. */
    if (conf->domain != NULL) {
	rc = proxy_needsdomain(r, url, conf->domain);
	if (ap_is_HTTP_REDIRECT(rc))
	    return HTTP_MOVED_PERMANENTLY;
    }

    *p = '\0';
    scheme = ap_pstrdup(r->pool, url);
    *p = ':';

    /* Check URI's destination host against NoProxy hosts */
    /* Bypass ProxyRemote server lookup if configured as NoProxy */
    /* we only know how to handle communication to a proxy via http */
    /*if (strcasecmp(scheme, "http") == 0) */
    {
	int ii;
	struct dirconn_entry *list = (struct dirconn_entry *) conf->dirconn->elts;

	for (direct_connect = ii = 0; ii < conf->dirconn->nelts && !direct_connect; ii++) {
	    direct_connect = list[ii].matcher(&list[ii], r);
	}
#if DEBUGGING
	ap_log_rerror(APLOG_MARK, APLOG_DEBUG|APLOG_NOERRNO, r,
		     (direct_connect) ? "NoProxy for %s" : "UseProxy for %s",
		     r->uri);
#endif
    }

/* firstly, try a proxy, unless a NoProxy directive is active */

    if (!direct_connect)
	for (i = 0; i < proxies->nelts; i++) {
	    p = strchr(ents[i].scheme, ':');	/* is it a partial URL? */
	    if (strcmp(ents[i].scheme, "*") == 0 ||
		(p == NULL && strcasecmp(scheme, ents[i].scheme) == 0) ||
		(p != NULL &&
	       strncasecmp(url, ents[i].scheme, strlen(ents[i].scheme)) == 0)) {
		/* CONNECT is a special method that bypasses the normal
		 * proxy code.
		 */
		if (r->method_number == M_CONNECT)
		    rc = ap_proxy_connect_handler(r, cr, url, ents[i].hostname,
					       ents[i].port);
/* we only know how to handle communication to a proxy via http */
		else if (strcasecmp(ents[i].protocol, "http") == 0)
		    rc = ap_proxy_http_handler(r, cr, url, ents[i].hostname,
					    ents[i].port);
		else
		    rc = DECLINED;

		/* an error or success */
		if (rc != DECLINED && rc != HTTP_BAD_GATEWAY)
		    return rc;
		/* we failed to talk to the upstream proxy */
	    }
	}

/* otherwise, try it direct */
/* N.B. what if we're behind a firewall, where we must use a proxy or
 * give up??
 */
    /* handle the scheme */
    if (r->method_number == M_CONNECT)
	return ap_proxy_connect_handler(r, cr, url, NULL, 0);
    if (strcasecmp(scheme, "http") == 0)
	return ap_proxy_http_handler(r, cr, url, NULL, 0);
    if (strcasecmp(scheme, "ftp") == 0)
	return ap_proxy_ftp_handler(r, cr, url);
    else
	return NOT_IMPLEMENTED;
}

/* -------------------------------------------------------------- */
/* Setup configurable data */

static void *
     create_proxy_config(pool *p, server_rec *s)
{
    proxy_server_conf *ps = ap_pcalloc(p, sizeof(proxy_server_conf));

    ps->proxies = ap_make_array(p, 10, sizeof(struct proxy_remote));
    ps->aliases = ap_make_array(p, 10, sizeof(struct proxy_alias));
    ps->raliases = ap_make_array(p, 10, sizeof(struct proxy_alias));
    ps->noproxies = ap_make_array(p, 10, sizeof(struct noproxy_entry));
    ps->dirconn = ap_make_array(p, 10, sizeof(struct dirconn_entry));
    ps->nocaches = ap_make_array(p, 10, sizeof(struct nocache_entry));
    ps->allowed_connect_ports = ap_make_array(p, 10, sizeof(int));
    ps->domain = NULL;
    ps->viaopt = via_off; /* initially backward compatible with 1.3.1 */
    ps->req = 0;

    ps->cache.root = NULL;
    ps->cache.space = DEFAULT_CACHE_SPACE;
    ps->cache.maxexpire = DEFAULT_CACHE_MAXEXPIRE;
    ps->cache.defaultexpire = DEFAULT_CACHE_EXPIRE;
    ps->cache.lmfactor = DEFAULT_CACHE_LMFACTOR;
    ps->cache.gcinterval = -1;
    /* at these levels, the cache can have 2^18 directories (256,000)  */
    ps->cache.dirlevels = 3;
    ps->cache.dirlength = 1;
    ps->cache.cache_completion = DEFAULT_CACHE_COMPLETION;

    return ps;
}

static const char *
     add_proxy(cmd_parms *cmd, void *dummy, char *f, char *r)
{
    server_rec *s = cmd->server;
    proxy_server_conf *conf =
    (proxy_server_conf *) ap_get_module_config(s->module_config, &proxy_module);
    struct proxy_remote *new;
    char *p, *q;
    int port;

    p = strchr(r, ':');
    if (p == NULL || p[1] != '/' || p[2] != '/' || p[3] == '\0')
	return "ProxyRemote: Bad syntax for a remote proxy server";
    q = strchr(p + 3, ':');
    if (q != NULL) {