mod_proxy.c

来自「apache服务器源代码（版本号：2.2.2）」· C语言 代码 · 共 1,862 行 · 第 1/5 页

static int proxy_detect(request_rec *r)
{
    void *sconf = r->server->module_config;
    proxy_server_conf *conf =
        (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);

    /* Ick... msvc (perhaps others) promotes ternary short results to int */

    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_scheme(r))
              && ap_matches_request_vhost(r, r->parsed_uri.hostname,
                                          (apr_port_t)(r->parsed_uri.port_str ? r->parsed_uri.port
                                                       : ap_default_port(r))))) {
            r->proxyreq = PROXYREQ_PROXY;
            r->uri = r->unparsed_uri;
            r->filename = apr_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 = PROXYREQ_PROXY;
        r->uri = r->unparsed_uri;
        r->filename = apr_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) {
           if ((ent[i].real[0] == '!') && (ent[i].real[1] == 0)) {
               return DECLINED;
           }

           r->filename = apr_pstrcat(r->pool, "proxy:", ent[i].real,
                                     r->uri + len, NULL);
           r->handler = "proxy-server";
           r->proxyreq = PROXYREQ_REVERSE;
           return OK;
       }
    }
    return DECLINED;
}

static int proxy_walk(request_rec *r)
{
    proxy_server_conf *sconf = ap_get_module_config(r->server->module_config,
                                                    &proxy_module);
    ap_conf_vector_t *per_dir_defaults = r->server->lookup_defaults;
    ap_conf_vector_t **sec_proxy = (ap_conf_vector_t **) sconf->sec_proxy->elts;
    ap_conf_vector_t *entry_config;
    proxy_dir_conf *entry_proxy;
    int num_sec = sconf->sec_proxy->nelts;
    /* XXX: shouldn't we use URI here?  Canonicalize it first?
     * Pass over "proxy:" prefix
     */
    const char *proxyname = r->filename + 6;
    int j;

    for (j = 0; j < num_sec; ++j)
    {
        entry_config = sec_proxy[j];
        entry_proxy = ap_get_module_config(entry_config, &proxy_module);

        /* XXX: What about case insensitive matching ???
         * Compare regex, fnmatch or string as appropriate
         * If the entry doesn't relate, then continue
         */
        if (entry_proxy->r
              ? ap_regexec(entry_proxy->r, proxyname, 0, NULL, 0)
              : (entry_proxy->p_is_fnmatch
                   ? apr_fnmatch(entry_proxy->p, proxyname, 0)
                   : strncmp(proxyname, entry_proxy->p,
                                        strlen(entry_proxy->p)))) {
            continue;
        }
        per_dir_defaults = ap_merge_per_dir_configs(r->pool, per_dir_defaults,
                                                             entry_config);
    }

    r->per_dir_config = per_dir_defaults;

    return OK;
}

static int proxy_map_location(request_rec *r)
{
    int access_status;

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

    /* Don't let the core or mod_http map_to_storage hooks handle this,
     * We don't need directory/file_walk, and we want to TRACE on our own.
     */
    if ((access_status = proxy_walk(r))) {
        ap_die(access_status, r);
        return access_status;
    }

    return OK;
}
/* -------------------------------------------------------------- */
/* Fixup the filename */

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

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

    /* XXX: Shouldn't we try this before we run the proxy_walk? */
    url = &r->filename[6];

    /* canonicalise each specific scheme */
    if ((access_status = proxy_run_canon_handler(r, url))) {
        return access_status;
    }

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

    return OK;      /* otherwise; we've done the best we can */
}
/* 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 = apr_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 = apr_pstrcat(r->pool, r->parsed_uri.hostname,
                                         domain, NULL);
    nuri = apr_uri_unparse(r->pool,
                           &r->parsed_uri,
                           APR_URI_UNP_REVEALPASSWORD);

    apr_table_set(r->headers_out, "Location", nuri);
    ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r,
                  "Domain missing: %s sent to %s%s%s", r->uri,
                  apr_uri_unparse(r->pool, &r->parsed_uri,
                                  APR_URI_UNP_OMITUSERINFO),
                  ref ? " from " : "", ref ? ref : "");

    return HTTP_MOVED_PERMANENTLY;
}

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

static int proxy_handler(request_rec *r)
{
    char *uri, *scheme, *p;
    const char *p2;
    void *sconf = r->server->module_config;
    proxy_server_conf *conf = (proxy_server_conf *)
        ap_get_module_config(sconf, &proxy_module);
    apr_array_header_t *proxies = conf->proxies;
    struct proxy_remote *ents = (struct proxy_remote *) proxies->elts;
    int i, rc, access_status;
    int direct_connect = 0;
    const char *str;
    long maxfwd;
    proxy_balancer *balancer = NULL;
    proxy_worker *worker = NULL;
    int attempts = 0, max_attempts = 0;
    struct dirconn_entry *list = (struct dirconn_entry *)conf->dirconn->elts;

    /* is this for us? */
    if (!r->proxyreq || !r->filename || strncmp(r->filename, "proxy:", 6) != 0)
        return DECLINED;

    /* handle max-forwards / OPTIONS / TRACE */
    if ((str = apr_table_get(r->headers_in, "Max-Forwards"))) {
        maxfwd = strtol(str, NULL, 10);
        if (maxfwd < 1) {
            switch (r->method_number) {
            case M_TRACE: {
                int access_status;
                r->proxyreq = PROXYREQ_NONE;
                if ((access_status = ap_send_http_trace(r)))
                    ap_die(access_status, r);
                else
                    ap_finalize_request_protocol(r);
                return OK;
            }
            case M_OPTIONS: {
                int access_status;
                r->proxyreq = PROXYREQ_NONE;
                if ((access_status = ap_send_http_options(r)))
                    ap_die(access_status, r);
                else
                    ap_finalize_request_protocol(r);
                return OK;
            }
            default: {
                return ap_proxyerror(r, HTTP_BAD_GATEWAY,
                                     "Max-Forwards has reached zero - proxy loop?");
            }
            }
        }
        maxfwd = (maxfwd > 0) ? maxfwd - 1 : 0;
    }
    else {
        /* set configured max-forwards */
        maxfwd = conf->maxfwd;
    }
    apr_table_set(r->headers_in, "Max-Forwards",
                  apr_psprintf(r->pool, "%ld", (maxfwd > 0) ? maxfwd : 0));

    if (r->method_number == M_TRACE) {
        core_server_config *coreconf = (core_server_config *)
                            ap_get_module_config(sconf, &core_module);

        if (coreconf->trace_enable == AP_TRACE_DISABLE)
        {
            /* Allow "error-notes" string to be printed by ap_send_error_response()
             * Note; this goes nowhere, canned error response need an overhaul.
             */
            apr_table_setn(r->notes, "error-notes",
                           "TRACE forbidden by server configuration");
            apr_table_setn(r->notes, "verbose-error-to", "*");
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "proxy: TRACE forbidden by server configuration");
            return HTTP_FORBIDDEN;
        }

        /* Can't test ap_should_client_block, we aren't ready to send
         * the client a 100 Continue response till the connection has
         * been established
         */
        if (coreconf->trace_enable != AP_TRACE_EXTENDED
            && (r->read_length || r->read_chunked || r->remaining))
        {
            /* Allow "error-notes" string to be printed by ap_send_error_response()
             * Note; this goes nowhere, canned error response need an overhaul.
             */
            apr_table_setn(r->notes, "error-notes",
                           "TRACE with request body is not allowed");
            apr_table_setn(r->notes, "verbose-error-to", "*");
            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "proxy: TRACE with request body is not allowed");
            return HTTP_REQUEST_ENTITY_TOO_LARGE;
        }
    }

    uri = r->filename + 6;
    p = strchr(uri, ':');
    if (p == NULL) {
        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                      "proxy_handler no URL in %s", r->filename);
        return HTTP_BAD_REQUEST;
    }

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

    scheme = apr_pstrndup(r->pool, uri, p - uri);
    /* Check URI's destination host against NoProxy hosts */
    /* Bypass ProxyRemote server lookup if configured as NoProxy */
    for (direct_connect = i = 0; i < conf->dirconn->nelts &&
                                        !direct_connect; i++) {
        direct_connect = list[i].matcher(&list[i], r);
    }
#if DEBUGGING
    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                (direct_connect) ? "NoProxy for %s" : "UseProxy for %s",
                r->uri);
#endif

    do {
        char *url = uri;
        /* Try to obtain the most suitable worker */
        access_status = ap_proxy_pre_request(&worker, &balancer, r, conf, &url);
        if (access_status != OK) {
            /*
             * Only return if access_status is not HTTP_SERVICE_UNAVAILABLE
             * This gives other modules the chance to hook into the
             * request_status hook and decide what to do in this situation.
             */
            if (access_status != HTTP_SERVICE_UNAVAILABLE)
                return access_status;
            /*
             * Ensure that balancer is NULL if worker is NULL to prevent
             * potential problems in the post_request hook.
             */
            if (!worker)
                balancer = NULL;
            goto cleanup;
        }
        if (balancer && balancer->max_attempts_set && !max_attempts)
            max_attempts = balancer->max_attempts;
        /* firstly, try a proxy, unless a NoProxy directive is active */
        if (!direct_connect) {
            for (i = 0; i < proxies->nelts; i++) {
                p2 = ap_strchr_c(ents[i].scheme, ':');  /* is it a partial URL? */
                if (strcmp(ents[i].scheme, "*") == 0 ||
                    (ents[i].use_regex &&
                     ap_regexec(ents[i].regexp, url, 0, NULL, 0) == 0) ||
                    (p2 == NULL && strcasecmp(scheme, ents[i].scheme) == 0) ||
                    (p2 != NULL &&
                    strncasecmp(url, ents[i].scheme,
                                strlen(ents[i].scheme)) == 0)) {

                    /* handle the scheme */
                    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                                 "Trying to run scheme_handler against proxy");
                    access_status = proxy_run_scheme_handler(r, worker,
                                                             conf, url,
                                                             ents[i].hostname,
                                                             ents[i].port);

                    /* an error or success */
                    if (access_status != DECLINED &&
                        access_status != HTTP_BAD_GATEWAY) {
                        goto cleanup;
                    }
                    /* we failed to talk to the upstream proxy */
                }