mod_proxy.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

        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, 0, 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++) {
            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, conf, url, ents[i].hostname, ents[i].port);

                /* an error or success */
                if (access_status != DECLINED && access_status != HTTP_BAD_GATEWAY) {
                    return access_status;
                }
                /* 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 */
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                 "Trying to run scheme_handler");
    access_status = proxy_run_scheme_handler(r, conf, url, NULL, 0);
    if (DECLINED == access_status) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, r->server,
                    "proxy: No protocol handler was valid for the URL %s. "
                    "If you are using a DSO version of mod_proxy, make sure "
                    "the proxy submodules are included in the configuration "
                    "using LoadModule.", r->uri);
        return HTTP_FORBIDDEN;
    }
    return access_status;
}

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

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

    ps->sec_proxy = apr_array_make(p, 10, sizeof(ap_conf_vector_t *));
    ps->proxies = apr_array_make(p, 10, sizeof(struct proxy_remote));
    ps->aliases = apr_array_make(p, 10, sizeof(struct proxy_alias));
    ps->raliases = apr_array_make(p, 10, sizeof(struct proxy_alias));
    ps->noproxies = apr_array_make(p, 10, sizeof(struct noproxy_entry));
    ps->dirconn = apr_array_make(p, 10, sizeof(struct dirconn_entry));
    ps->allowed_connect_ports = apr_array_make(p, 10, sizeof(int));
    ps->domain = NULL;
    ps->viaopt = via_off; /* initially backward compatible with 1.3.1 */
    ps->viaopt_set = 0; /* 0 means default */
    ps->req = 0;
    ps->req_set = 0;
    ps->recv_buffer_size = 0; /* this default was left unset for some reason */
    ps->recv_buffer_size_set = 0;
    ps->io_buffer_size = AP_IOBUFSIZE;
    ps->io_buffer_size_set = 0;
    ps->maxfwd = DEFAULT_MAX_FORWARDS;
    ps->maxfwd_set = 0;
    ps->error_override = 0; 
    ps->error_override_set = 0; 
    ps->preserve_host_set = 0;
    ps->preserve_host = 0;    
    ps->timeout = 0;
    ps->timeout_set = 0;
    ps->badopt = bad_error;
    ps->badopt_set = 0;
    return ps;
}

static void * merge_proxy_config(apr_pool_t *p, void *basev, void *overridesv)
{
    proxy_server_conf *ps = apr_pcalloc(p, sizeof(proxy_server_conf));
    proxy_server_conf *base = (proxy_server_conf *) basev;
    proxy_server_conf *overrides = (proxy_server_conf *) overridesv;

    ps->proxies = apr_array_append(p, base->proxies, overrides->proxies);
    ps->sec_proxy = apr_array_append(p, base->sec_proxy, overrides->sec_proxy);
    ps->aliases = apr_array_append(p, base->aliases, overrides->aliases);
    ps->raliases = apr_array_append(p, base->raliases, overrides->raliases);
    ps->noproxies = apr_array_append(p, base->noproxies, overrides->noproxies);
    ps->dirconn = apr_array_append(p, base->dirconn, overrides->dirconn);
    ps->allowed_connect_ports = apr_array_append(p, base->allowed_connect_ports, overrides->allowed_connect_ports);

    ps->domain = (overrides->domain == NULL) ? base->domain : overrides->domain;
    ps->viaopt = (overrides->viaopt_set == 0) ? base->viaopt : overrides->viaopt;
    ps->req = (overrides->req_set == 0) ? base->req : overrides->req;
    ps->recv_buffer_size = (overrides->recv_buffer_size_set == 0) ? base->recv_buffer_size : overrides->recv_buffer_size;
    ps->io_buffer_size = (overrides->io_buffer_size_set == 0) ? base->io_buffer_size : overrides->io_buffer_size;
    ps->maxfwd = (overrides->maxfwd_set == 0) ? base->maxfwd : overrides->maxfwd;
    ps->error_override = (overrides->error_override_set == 0) ? base->error_override : overrides->error_override;
    ps->preserve_host = (overrides->preserve_host_set == 0) ? base->preserve_host : overrides->preserve_host;
    ps->timeout= (overrides->timeout_set == 0) ? base->timeout : overrides->timeout;
    ps->badopt = (overrides->badopt_set == 0) ? base->badopt : overrides->badopt;

    return ps;
}

static void *create_proxy_dir_config(apr_pool_t *p, char *dummy)
{
    proxy_dir_conf *new =
        (proxy_dir_conf *) apr_pcalloc(p, sizeof(proxy_dir_conf));

    /* Filled in by proxysection, when applicable */

    return (void *) new;
}

static void *merge_proxy_dir_config(apr_pool_t *p, void *basev, void *addv)
{
    proxy_dir_conf *new = (proxy_dir_conf *) apr_pcalloc(p, sizeof(proxy_dir_conf));
    proxy_dir_conf *add = (proxy_dir_conf *) addv;

    new->p = add->p;
    new->p_is_fnmatch = add->p_is_fnmatch;
    new->r = add->r;
    return new;
}


static const char *
    add_proxy(cmd_parms *cmd, void *dummy, const char *f1, const char *r1, int regex)
{
    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;
    char *r, *f, *scheme;
    regex_t *reg = NULL;
    int port;

    r = apr_pstrdup(cmd->pool, r1);
    scheme = apr_pstrdup(cmd->pool, r1);
    f = apr_pstrdup(cmd->pool, f1);
    p = strchr(r, ':');
    if (p == NULL || p[1] != '/' || p[2] != '/' || p[3] == '\0') {
        if (regex)
            return "ProxyRemoteMatch: Bad syntax for a remote proxy server";
        else
            return "ProxyRemote: Bad syntax for a remote proxy server";
    }
    else {
        scheme[p-r] = 0;
    }
    q = strchr(p + 3, ':');
    if (q != NULL) {
        if (sscanf(q + 1, "%u", &port) != 1 || port > 65535) {
            if (regex)
                return "ProxyRemoteMatch: Bad syntax for a remote proxy server (bad port number)";
            else
                return "ProxyRemote: Bad syntax for a remote proxy server (bad port number)";
        }
        *q = '\0';
    }
    else
        port = -1;
    *p = '\0';
    if (regex) {
        reg = ap_pregcomp(cmd->pool, f, REG_EXTENDED);
        if (!reg)
            return "Regular expression for ProxyRemoteMatch could not be compiled.";
    }
    else
        if (strchr(f, ':') == NULL)
            ap_str_tolower(f);		/* lowercase scheme */
    ap_str_tolower(p + 3);		/* lowercase hostname */

    if (port == -1) {
        port = apr_uri_port_of_scheme(scheme);
    }

    new = apr_array_push(conf->proxies);
    new->scheme = f;
    new->protocol = r;
    new->hostname = p + 3;
    new->port = port;
    new->regexp = reg;
    new->use_regex = regex;
    return NULL;
}

static const char *
    add_proxy_noregex(cmd_parms *cmd, void *dummy, const char *f1, const char *r1)
{
    return add_proxy(cmd, dummy, f1, r1, 0);
}

static const char *
    add_proxy_regex(cmd_parms *cmd, void *dummy, const char *f1, const char *r1)
{
    return add_proxy(cmd, dummy, f1, r1, 1);
}

static const char *
    add_pass(cmd_parms *cmd, void *dummy, const char *f, const 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_alias *new;
    if (r!=NULL && cmd->path == NULL ) {
        new = apr_array_push(conf->aliases);
        new->fake = f;
        new->real = r;
    } else if (r==NULL && cmd->path != NULL) {
        new = apr_array_push(conf->aliases);
        new->fake = cmd->path;
        new->real = f;
    } else {
        if ( r== NULL)
            return "ProxyPass needs a path when not defined in a location";
        else 
            return "ProxyPass can not have a path when defined in a location";
    }

     return NULL;
}

static const char *
    add_pass_reverse(cmd_parms *cmd, void *dummy, const char *f, const char *r)
{
    server_rec *s = cmd->server;
    proxy_server_conf *conf;
    struct proxy_alias *new;

    conf = (proxy_server_conf *)ap_get_module_config(s->module_config, 
                                                     &proxy_module);
    if (r!=NULL && cmd->path == NULL ) {
        new = apr_array_push(conf->raliases);
        new->fake = f;
        new->real = r;
    } else if (r==NULL && cmd->path != NULL) {
        new = apr_array_push(conf->raliases);
        new->fake = cmd->path;
        new->real = f;
    } else {
        if ( r == NULL)
            return "ProxyPassReverse needs a path when not defined in a location";
        else 
            return "ProxyPassReverse can not have a path when defined in a location";
    }

    return NULL;
}

static const char *
    set_proxy_exclude(cmd_parms *parms, void *dummy, const char *arg)
{
    server_rec *s = parms->server;
    proxy_server_conf *conf =
    ap_get_module_config(s->module_config, &proxy_module);
    struct noproxy_entry *new;
    struct noproxy_entry *list = (struct noproxy_entry *) conf->noproxies->elts;
    struct apr_sockaddr_t *addr;
    int found = 0;
    int i;

    /* Don't duplicate entries */
    for (i = 0; i < conf->noproxies->nelts; i++) {
        if (apr_strnatcasecmp(arg, list[i].name) == 0) { /* ignore case for host names */
            found = 1;
        }
    }

    if (!found) {
        new = apr_array_push(conf->noproxies);
        new->name = arg;
        if (APR_SUCCESS == apr_sockaddr_info_get(&addr, new->name, APR_UNSPEC, 0, 0, parms->pool)) {
            new->addr = addr;
        }
        else {
            new->addr = NULL;
        }
    }
    return NULL;
}

/*
 * Set the ports CONNECT can use
 */
static const char *
    set_allowed_ports(cmd_parms *parms, void *dummy, const char *arg)
{
    server_rec *s = parms->server;
    proxy_server_conf *conf =
        ap_get_module_config(s->module_config, &proxy_module);
    int *New;

    if (!apr_isdigit(arg[0]))
        return "AllowCONNECT: port number must be numeric";

    New = apr_array_push(conf->allowed_connect_ports);
    *New = atoi(arg);
    return NULL;
}

/* Similar to set_proxy_exclude(), but defining directly connected hosts,
 * which should never be accessed via the configured ProxyRemote servers
 */
static const char *
    set_proxy_dirconn(cmd_parms *parms, void *dummy, const char *arg)
{
    server_rec *s = parms->server;
    proxy_server_conf *conf =
    ap_get_module_config(s->module_config, &proxy_module);
    struct dirconn_entry *New;
    struct dirconn_entry *list = (struct dirconn_entry *) conf->dirconn->elts;
    int found = 0;
    int i;

    /* Don't duplicate entries */
    for (i = 0; i < conf->dirconn->nelts; i++) {
        if (strcasecmp(arg, list[i].name) == 0)
            found = 1;
    }

    if (!found) {
        New = apr_array_push(conf->dirconn);
        New->name = apr_pstrdup(parms->pool, arg);
        New->hostaddr = NULL;

	if (ap_proxy_is_ipaddr(New, parms->pool)) {
#if DEBUGGING
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "Parsed addr %s", inet_ntoa(New->addr));
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "Parsed mask %s", inet_ntoa(New->mask));
#endif
	}
	else if (ap_proxy_is_domainname(New, parms->pool)) {
            ap_str_tolower(New->name);
#if DEBUGGING
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "Parsed domain %s", New->name);
#endif
        }
        else if (ap_proxy_is_hostname(New, parms->pool)) {
            ap_str_tolower(New->name);
#if DEBUGGING
            ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
                         "Parsed host %s", New->name);
#endif
        }
        else {
            ap_proxy_is_word(New, parms->pool);
#if DEBUGGING
            fprintf(stderr, "Parsed word %s\n", New->name);
#endif
        }
    }
    return NULL;
}