static const char *start_ifbind(cmd_parms *cmd, void *dummy, const char *arg)

{

    const char *endp;

    int ipconfigured = 0;

    int not = 0;

    char *host, *scope_id;

    apr_port_t port; 

    apr_status_t rv;

    apr_socket_t *tmp_sock;

    apr_sockaddr_t *sa;

    endp = ap_strrchr_c(arg, '>');

    if (endp == NULL) {

        return unclosed_directive(cmd);

    }

    arg = apr_pstrndup(cmd->pool, arg, endp - arg);

    if (arg[0] == '!') {

        not = 1;

        arg++;

    }

    rv = apr_parse_addr_port(&host, &scope_id, &port, arg, cmd->pool);

    if (rv != APR_SUCCESS) {

        return "Invalid address or port";

    }

    if (!host || !strcmp(host, "*")) {

        return "A host IP address must be set";

    }

    if (scope_id) {

        /* XXX scope id support is useful with link-local IPv6 addresses */

        return "Scope id is not supported";

    }

    if ((rv = apr_sockaddr_info_get(&sa, host, APR_UNSPEC, 0, 0, cmd->pool)) == APR_SUCCESS) {

        if ((rv = apr_socket_create(&tmp_sock, sa->family, SOCK_STREAM, cmd->pool))

            == APR_SUCCESS) {

            if ((rv = apr_bind(tmp_sock, sa)) == APR_SUCCESS) {

                ipconfigured = 1;

            }

            apr_socket_close(tmp_sock);

        }

    }

    if (ipconfigured) {

        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, cmd->server,

            "IfBind: IP %s exists on network interface", arg);

    }

    else {

        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, rv, cmd->server,

            "IfBind: IP %s does not exist on network interface", arg);

    }

    if ((!not && ipconfigured) || (not && !ipconfigured)) {  

        ap_directive_t *parent = NULL;

        ap_directive_t *current = NULL;

        const char *retval;

        retval = ap_build_cont_config(cmd->pool, cmd->temp_pool, cmd,

                                      &current, &parent, "<IfBind");

        *(ap_directive_t **)dummy = current;

        return retval;

    }

    else {

        *(ap_directive_t **)dummy = NULL;

        return ap_soak_end_container(cmd, "<IfBind");

    }

}

AP_INIT_TAKE1("<IfBind", start_ifbind, NULL, EXEC_ON_READ | OR_ALL,

  "Container for directives based on an IP Address configured on the host network interface"),