######## DoS prevention module ########
# Default "order" is "deny,allow".
# So if there is no data from DB request will be permitted by default.
#
modparam("htable", "htable", "acl=>initval=-1;autoexpire=7200")

#!trydef ACL_MESSAGE_DENY "Rejected by ACL"
#!trydef ACL_CODE_DENY "603"
#!trydef ACL_ORDER_ALLOW_DENY "allow,deny"
#!trydef ACL_IP_ADDR_ANY "0.0.0.0/0"

#!trydef IP_REGEX "[0-9]{1,3}\.[0-9]{1,3}.[0-9]{1,3}\.[0-9]{1,3}"

## Route for ACL functionality
route[ACL_CHECK] {

    # If packet came from platform or from 4 class MERA, do not check it
    if (isflagset(FLAG_INTERNALLY_SOURCED) || isflagset(FLAG_TRUSTED_SOURCE) ) {
        xlog("L_DEBUG", "$ci|ACL|Trusted source IP($si) ignoring\n");
        return;
    }


    if (isflagset(FLAG_IS_REPLY)) {
        $var(sip-packet) = $rs;
    } else {
        $var(sip-packet) = $rm;
    }

    # FIX for BYE method with IP instead of REALM in From, take REALM from To header
    if ($fd =~ IP_REGEX) {
        xlog("L_WARNING","$ci|ACL-realm|Fix for $var(sip-packet) with IP in from URI: use to-domain\n");
        $var(realm) = $td;
    } else {
        $var(realm) = $fd;
    }

    $var(acl-realm-request) = "false";
    $var(acl-device-request) = "false";

    $var(realm-decision) = $sht(acl=>$var(realm)/$si);

    if ($var(realm-decision) == -1) { # we do not have cached decision
        $var(acl-realm-request) = "true";
    } else if ($var(realm-decision) == 1 ){ # We have cached decision, let's use it
        xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(realm)\n");
    } else {
        if (!isflagset(FLAG_IS_REPLY)) {
            sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
        }
        xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(realm)\n");
        exit;
    }

    if (not_empty("$fU")) {
        if ($fd =~ IP_REGEX) {
            xlog("L_WARNING","$ci|ACL-device|Fix for $var(sip-packet) with IP in from URI: use to-domain\n");
            $var(device) = $fU + "@" + $td;
        } else {
            $var(device) = $fU + "@" + $fd;
        }
        $var(device-decision) = $sht(acl=>$var(device)/$si);

        if ($var(device-decision) == -1) { # we do not have cached decision
            $var(acl-device-request) = "true";
        } else if ($var(device-decision) == 1 ){ # We have cached decision, let's use it
            xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(device)\n");
        } else {
            if (!isflagset(FLAG_IS_REPLY)) {
                sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
            }
            xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(device)\n");
            exit;
        }
    }


    if ($var(acl-realm-request) == "true" || $var(acl-device-request) == "true") {
        if (not_empty("$fU"))
            $var(query) = "{'Event-Category': 'acl', 'Event-Name': 'query', 'Entity': '" + $var(device) + "', 'With-Realm': " + $var(acl-realm-request) + "}";
        else
            $var(query) = "{'Event-Category': 'acl', 'Event-Name': 'query', 'Entity': '" + $var(realm) + "'}";
        xlog("L_DBG", "$ci|ACL log|Query: $var(query)\n");
        sl_send_reply("100", "Attempting K query");
        if (kazoo_query("frontier", "sbc_config", $var(query), "$var(acl-response)")) {
            xlog("L_DBG", "$ci|ACL log|Response: $var(acl-response)\n");

            kazoo_json($var(acl-response), "Realm.Order",       "$var(acl-realm-order)");
            kazoo_json($var(acl-response), "Realm.CIDR",        "$var(acl-realm-cidr)");
            kazoo_json($var(acl-response), "Device.Order",      "$var(acl-device-order)");
            kazoo_json($var(acl-response), "Device.CIDR",       "$var(acl-device-cidr)");
            kazoo_json($var(acl-response), "Device.User-Agent", "$var(acl-device-ua)");

        } else {
            xlog("L_ERROR","$ci|ACL log|DB is unreachable\n");
            $sht(acl=>$var(device)/$si) = 1;
            xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(device)\n");
            return;
        }

        route(ACL_CHECK_REALM);
        if (not_empty("$fU")) {
            route(ACL_CHECK_DEVICE);
        }
    }

}

# Check ORDER setting for REALM
route[ACL_CHECK_REALM] {
    if (not_empty("$var(acl-realm-order)")) {
        if ($var(acl-realm-order) == ACL_ORDER_ALLOW_DENY) {
            route(ACL_CHECK_REALM_ALLOW);
        } else {
            route(ACL_CHECK_REALM_DENY);
        }
    } else {
        xlog("L_INFO","$ci|ACL-realm|undefined Order in response for $var(realm)\n");
        $sht(acl=>$var(realm)/$si) = 1;
        xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(realm)\n");
    }
}

route[ACL_CHECK_REALM_ALLOW] {
    if (not_empty("$var(acl-realm-cidr)")) {
        $var(i) = 0;
        kazoo_json($var(acl-response), "Realm.CIDR[$var(i)]", "$var(record)");;
        while(not_empty("$var(record)")) {
            xlog("L_INFO", "$ci|ACL-realm|checking if $si is in $var(record)\n");
            if (($var(record) == ACL_IP_ADDR_ANY) || is_in_subnet("$si", $var(record))) {
                $sht(acl=>$var(realm)/$si) = 1;
                xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(realm)\n");
                return;
            }
            $var(i) = $var(i) + 1;
            kazoo_json($var(acl-response), "Realm.CIDR[$var(i)]", "$var(record)");;
        }
    } else {
        xlog("L_INFO", "$ci|ACL-realm|undefined CIDR in response for $var(realm)\n");
    }
    # Remember in CACHE and DENY
    $sht(acl=>$var(realm)/$si) = 0;
    if (!isflagset(FLAG_IS_REPLY)) {
        sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
    }
    xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(realm)\n");
    exit;
}

route[ACL_CHECK_REALM_DENY] {
    $var(size) = $(kzR{kz.json,Realm.CIDR.length});
    if (not_empty("$var(acl-realm-cidr)")) {
        $var(i) = 0;
        kazoo_json($var(acl-response), "Realm.CIDR[$var(i)]", "$var(record)");;
        while(not_empty("$var(record)")) {
            xlog("L_INFO", "$ci|ACL-realm|checking if $si is in $var(record)\n");
            if (($var(record) == ACL_IP_ADDR_ANY) || is_in_subnet("$si", $var(record))) {
                $sht(acl=>$var(realm)/$si) = 0;
                if (!isflagset(FLAG_IS_REPLY)) {
                    sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
                }
                xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(realm)\n");
                exit;
            }
            $var(i) = $var(i) + 1;
            kazoo_json($var(acl-response), "Realm.CIDR[$var(i)]", "$var(record)");;
        }
    } else {
        xlog("L_INFO", "$ci|ACL-realm|undefined CIDR in response for $var(realm)\n");
    }
    # Remember in CACHE and ALLOW
    $sht(acl=>$var(realm)/$si) = 1;
    xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(realm)\n");
    return;
}

# Check ORDER setting for DEVICE
route[ACL_CHECK_DEVICE] {
    if (not_empty("$var(acl-device-order)")) {
        if ($var(acl-device-order) == ACL_ORDER_ALLOW_DENY) {
            route(ACL_CHECK_DEVICE_ALLOW);
        } else {
            route(ACL_CHECK_DEVICE_DENY);
        }
    } else {
        xlog("L_INFO","$ci|ACL-device|undefined Order in response for $var(device)\n");
        $sht(acl=>$var(device)/$si) = 1;
        xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(device)\n");
    }
}

route[ACL_CHECK_DEVICE_ALLOW] {
    if (!not_empty("$var(acl-device-ua)") || (not_empty("$var(acl-device-ua)") && $ua =~ $var(acl-device-ua))) {
        if (not_empty("$var(acl-device-cidr)")) {
            $var(i) = 0;
            kazoo_json($var(acl-response), "Device.CIDR[$var(i)]", "$var(record)");;
            while(not_empty("$var(record)")) {
                xlog("L_INFO", "$ci|ACL-realm|checking if $si is in $var(record)\n");
                if (($var(record) == ACL_IP_ADDR_ANY) || is_in_subnet("$si", $var(record))) {
                    $sht(acl=>$var(device)/$si) = 1;
                    xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(device)\n");
                    return;
                }
                $var(i) = $var(i) + 1;
                kazoo_json($var(acl-response), "Device.CIDR[$var(i)]", "$var(record)");;
            }
        } else {
            xlog("L_INFO", "$ci|ACL-realm|undefined CIDR in response for $var(device)\n");
        }
    }
    # Remember in CACHE and DENY
    $sht(acl=>$var(device)/$si) = 0;
    if (!isflagset(FLAG_IS_REPLY)) {
        sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
    }
    xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(device)\n");
    exit;
}

route[ACL_CHECK_DEVICE_DENY] {
    if (not_empty("$var(acl-device-ua)") && !($ua =~ $var(acl-device-ua))) {
        $sht(acl=>$var(device)/$si) = 0;
        if (!isflagset(FLAG_IS_REPLY)) {
            sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
        }
        xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(device)\n");
        exit;
    }

    if (not_empty("$var(acl-device-cidr)")) {
        $var(i) = 0;
        kazoo_json($var(acl-response), "Device.CIDR[$var(i)]", "$var(record)");;
        while(not_empty("$var(record)")) {
            xlog("L_INFO", "$ci|ACL-device|checking if $si is in $var(record)\n");
            if (($var(record) == ACL_IP_ADDR_ANY) || is_in_subnet("$si", $var(record))) {
                $sht(acl=>$var(device)/$si) = 0;
                if (!isflagset(FLAG_IS_REPLY)) {
                    sl_send_reply(ACL_CODE_DENY, ACL_MESSAGE_DENY);
                }
                xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is rejected by ACL for $var(device)\n");
                exit;
            }
            $var(i) = $var(i) + 1;
            kazoo_json($var(acl-response), "Device.CIDR[$var(i)]", "$var(record)");;
        }
    } else {
        xlog("L_INFO", "$ci|ACL-device|undefined CIDR in response for $var(device)\n");
    }
    # Remember in CACHE and ALLOW
    $sht(acl=>$var(device)/$si) = 1;
    xlog("L_INFO", "$ci|ACL|$var(sip-packet) from $si is permitted by ACL for $var(device)\n");
    return;
}

event_route[kazoo:consumer-event-acl-acl-flush]
{
    if( $(kzE{kz.json,Device}) != "" ) {
        $var(device_regexp) = $(kzE{kz.json,Device}) + "@" + $(kzE{kz.json,Realm}) + "/.*" ;
        xlog("L_INFO","|ACL-Flush| Flush ACL for Device. Regexp: $var(device_regexp)\n");
        sht_rm_name_re("acl=>$var(device_regexp)");
    } else {
        $var(realm_regexp) = "^" + $(kzE{kz.json,Realm}) + "/.*" ;
        xlog("L_INFO","|ACL-Flush| Flush ACL for Realm. Regexp: $var(realm_regexp)\n");
        sht_rm_name_re("acl=>$var(realm_regexp)");
    }

}