NeutronRouterExternal_gateway_infoExtension.md

Neutron Router external_gateway_info extension

• extension : neutron/extensions/l3_ext_gw_mode.py

class L3_NAT_dbonly_mixin(l3_db.L3_NAT_dbonly_mixin)

对 router external_gateway_info extension 逻辑业务的实现。

neutron/db/l3_gwmode_db.py

子类和父类的名称是一样的，但是在不同的模块

    db_base_plugin_v2.NeutronDbPluginV2.register_dict_extend_funcs(
        l3.ROUTERS, ['_extend_router_dict_gw_mode'])

    def _extend_router_dict_gw_mode(self, router_res, router_db):
        if router_db.gw_port_id:
            nw_id = router_db.gw_port['network_id']
            router_res[EXTERNAL_GW_INFO] = {
                'network_id': nw_id,
                'enable_snat': router_db.enable_snat,
                'external_fixed_ips': [
                    {'subnet_id': ip["subnet_id"],
                     'ip_address': ip["ip_address"]}
                    for ip in router_db.gw_port['fixed_ips']
                ]
            }

扩展 router 的显示属性

def _update_router_gw_info(self, context, router_id, info, router=None)

1. 若 router 为空则调用 _get_router 获取其数据库记录
2. 调用 _get_enable_snat 获取该 router 是否支持 snat
3. 调用 L3_NAT_dbonly_mixin._update_router_gw_info 方法实现具体的业务逻辑

def _get_enable_snat(info)

1. 若 info 数据中包含 enable_snat 属性，则使用 info 中的数据
2. 若不包含，则使用默认的 cfg.CONF.enable_snat_by_default

def _build_routers_list(self, context, routers, gw_ports)

    def _build_routers_list(self, context, routers, gw_ports):
        for rtr in routers:
            gw_port_id = rtr['gw_port_id']
            # Collect gw ports only if available
            if gw_port_id and gw_ports.get(gw_port_id):
                rtr['gw_port'] = gw_ports[gw_port_id]
                # Add enable_snat key
                rtr['enable_snat'] = rtr[EXTERNAL_GW_INFO]['enable_snat']
        return routers