【neutron源码分析】create_network/create_subnet/create_port源码分析

桃扇骨 2022-06-12 09:21 354阅读 0赞

## 1. network源码分析 ##

通过执行命令创建网络上，neutron net-create xxxxx

首先neutronclient发送HTTP请求给neutron-server，调用create函数。

def create(self, request, body=None, **kwargs):
        self._notifier.info(request.context, self._resource + '.create.start', body)
        return self._create(request, body, **kwargs)

def _create(self, request, body, **kwargs): """Creates a new instance of the requested entity.""" parent_id = kwargs.get(self._parent_id_name) body = Controller.prepare_request_body(request.context, copy.deepcopy(body), True, self._resource, self._attr_info, allow_bulk=self._allow_bulk) action = self._plugin_handlers[self.CREATE] # Check authz if self._collection in body: # Have to account for bulk create items = body[self._collection] else: items = [body] policy.init() request_deltas = collections.defaultdict(int) for item in items: self._validate_network_tenant_ownership(request, item[self._resource]) policy.enforce(request.context, action, item[self._resource], pluralized=self._collection) if 'tenant_id' not in item[self._resource]: # no tenant_id - no quota check continue tenant_id = item[self._resource]['tenant_id'] request_deltas[tenant_id] += 1 # Quota enforcement reservations = [] try: for (tenant, delta) in request_deltas.items(): reservation = quota.QUOTAS.make_reservation( request.context, tenant, { self._resource: delta}, self._plugin) reservations.append(reservation) except exceptions.QuotaResourceUnknown as e: # We don't want to quota this resource LOG.debug(e) if self._collection in body and self._native_bulk: # plugin does atomic bulk create operations objs = do_create(body, bulk=True) # Use first element of list to discriminate attributes which # should be removed because of authZ policies fields_to_strip = self._exclude_attributes_by_policy( request.context, objs[0]) return notify({ self._collection: [self._filter_attributes( request.context, obj, fields_to_strip=fields_to_strip) for obj in objs]}) else: if self._collection in body: # Emulate atomic bulk behavior objs = do_create(body, bulk=True, emulated=True) return notify({ self._collection: objs}) else: obj = do_create(body) self._send_nova_notification(action, {}, { self._resource: obj}) return notify({ self._resource: self._view(request.context, obj)})

body内容大概如下所示：

\{  
     u'network ': \{  
        'router: external': False,  
        'availability\_zone\_hints': \[  
              
        \],  
        'description': '',  
        'provider: physical\_network': <objectobjectat0x7f67c71e03a0>,  
        u'admin\_state\_up': True,  
        ' tenant\_id ': u'6b13cdad170c4674a061b9ff69847164',  
        'segments': <objectobjectat0x7f67c71e03a0>,  
        'dns\_domain': '',  
        'provider: network\_type': <objectobjectat0x7f67c71e03a0>,  
        'is\_default': False,  
        'qos\_policy\_id': None,  
        'shared': False,  
        'port\_security\_enabled': True,  
        'provider: segmentation\_id': <objectobjectat0x7f67c71e03a0>,  
        u 'name': u'zzl-test11111 '  
    \}  
\}

action: create\_network

def do_create(body, bulk=False, emulated=False): kwargs = {self._parent_id_name: parent_id} if parent_id else {} if bulk and not emulated: obj_creator = getattr(self._plugin, "%s_bulk" % action) else: obj_creator = getattr(self._plugin, action) try: if emulated: return self._emulate_bulk_create(obj_creator, request, body, parent_id) else: if self._collection in body: # This is weird but fixing it requires changes to the # plugin interface kwargs.update({self._collection: body}) else: kwargs.update({self._resource: body}) return obj_creator(request.context, **kwargs) except Exception: # In case of failure the plugin will always raise an # exception. Cancel the reservation with excutils.save_and_reraise_exception(): for reservation in reservations: quota.QUOTAS.cancel_reservation( request.context, reservation.reservation_id)

obj\_creator函数中self.\_plugin为ml2，action为create\_network: Ml2Plugin.create\_network

neutron.plugins.ml2.plugin.Ml2Plugin

位置：neutron/plugins/ml2/plugin.py

def create_network(self, context, network):
        result, mech_context = self._create_network_db(context, network)
        try:
            self.mechanism_manager.create_network_postcommit(mech_context)
        except ml2_exc.MechanismDriverError:
            with excutils.save_and_reraise_exception():
                LOG.error(_LE("mechanism_manager.create_network_postcommit " "failed, deleting network '%s'"), result['id'])
                self.delete_network(context, result['id'])
    
        return result

调用\_create\_network\_db，写入数据库操作具体如下：

def _create_network_db(self, context, network): net_data = network[attributes.NETWORK] tenant_id = net_data['tenant_id'] session = context.session with session.begin(subtransactions=True): self._ensure_default_security_group(context, tenant_id) net_db = self.create_network_db(context, network) result = self._make_network_dict(net_db, process_extensions=False, context=context) self.extension_manager.process_create_network(context, net_data, result) self._process_l3_create(context, result, net_data) net_data['id'] = result['id'] self.type_manager.create_network_segments(context, net_data, tenant_id) self.type_manager.extend_network_dict_provider(context, result) # Update the transparent vlan if configured if utils.is_extension_supported(self, 'vlan-transparent'): vlt = vlantransparent.get_vlan_transparent(net_data) net_db['vlan_transparent'] = vlt result['vlan_transparent'] = vlt mech_context = driver_context.NetworkContext(self, context, result) self.mechanism_manager.create_network_precommit(mech_context) if net_data.get(api.MTU, 0) > 0: net_db[api.MTU] = net_data[api.MTU] result[api.MTU] = net_data[api.MTU] if az_ext.AZ_HINTS in net_data: self.validate_availability_zones(context, 'network', net_data[az_ext.AZ_HINTS]) az_hints = az_ext.convert_az_list_to_string( net_data[az_ext.AZ_HINTS]) net_db[az_ext.AZ_HINTS] = az_hints result[az_ext.AZ_HINTS] = az_hints

**net\_db数据大致如下：**

\{  
    tenant\_id=u'6b13cdad170c4674a061b9ff69847164',  
    id='01978067-94f2-4758-b124-b33413a9d9f2',  
    name=u'xxxxx',  
    status='ACTIVE',  
    admin\_state\_up=True,  
    mtu=1500,  
    vlan\_transparent=None,  
    availability\_zone\_hints=None,  
    standard\_attr\_id=1097  
\}

create\_network\_db是真正的写入数据库操作

data 大致如下：

\{  
    'router: external': False,  
    'availability\_zone\_hints': \[  
          
    \],  
    'description': '',  
    'provider: physical\_network': <objectobjectat0x7fa333ea23a0>,  
    u'admin\_state\_up': True,  
    'tenant\_id': u'6b13cdad170c4674a061b9ff69847164',  
    'segments': <objectobjectat0x7fa333ea23a0>,  
    'dns\_domain': '',  
    'provider: network\_type': <objectobjectat0x7fa333ea23a0>,  
    'is\_default': False,  
    'qos\_policy\_id': None,  
    'shared': False,  
    'port\_security\_enabled': True,  
    'provider: segmentation\_id': <objectobjectat0x7fa333ea23a0>,  
    u'name': u'xxxxx'  
\}

extension\_manager.process\_create\_network：创建ml2\_conf.ini配置文件选项为：extension\_drivers = port\_security, qos，根据

port_security = neutron.plugins.ml2.extensions.port_security:PortSecurityExtensionDriver

qos = neutron.plugins.ml2.extensions.qos:QosExtensionDriver

class QosExtensionDriver(api.ExtensionDriver): def process_create_network(self, context, data, result): self.core_ext_handler.process_fields( context, base_core.NETWORK, data, result)

如果请求含有qos\_policy\_id，则调用update\_network\_policy

class PortSecurityExtensionDriver(api.ExtensionDriver, ps_db_common.PortSecurityDbCommon, common_db_mixin.CommonDbMixin): _supported_extension_alias = 'port-security' def process_create_network(self, context, data, result): # Create the network extension attributes. if psec.PORTSECURITY not in data: data[psec.PORTSECURITY] = psec.DEFAULT_PORT_SECURITY self._process_network_port_security_create(context, data, result)

将写入数据库中

mechanism\_manager.create\_network\_precommit

def create_network_precommit(self, context):
        """Notify all mechanism drivers during network creation. :raises: DB retriable error if create_network_precommit raises them See neutron.db.api.is_retriable for what db exception is retriable or neutron.plugins.ml2.common.MechanismDriverError if any mechanism driver create_network_precommit call fails. Called within the database transaction. If a mechanism driver raises an exception, then a MechanismDriverError is propogated to the caller, triggering a rollback. There is no guarantee that all mechanism drivers are called in this case. """ self._check_vlan_transparency(context)
        self._call_on_drivers("create_network_precommit", context, raise_db_retriable=True)

def _call_on_drivers(self, method_name, context, continue_on_failure=False, raise_db_retriable=False):
     error = False for driver in self.ordered_mech_drivers:
            try:
                getattr(driver.obj, method_name)(context)

根据配置文件ml2.conf.ini中选项：mechanism\_drivers = networking-plato，

*  调用该模块：create\_network\_precommit
 *  然后调用create\_network\_postcommit

## 2. subnet源码分析 ##

通过执行命令创建网络上，neutron subnet-create xxxxx 10.10.10.0/24 --name subnet-xxxxx --gateway 10.10.10.1 --enable\_dhcp true

![Image 1][]

同样经过neutron.api.v2.base.py中\_create函数，body数据为：

\{   
    u'subnet': \{   
        'host\_routes': <objectobjectat0x7f24c067a3a0>,  
        'prefixlen': <objectobjectat0x7f24c067a3a0>,  
        u'name': u'subnet-xxxxx',  
        u'enable\_dhcp': True,  
        u'network\_id': u'01978067-94f2-4758-b124-b33413a9d9f2',  
        'tenant\_id': u'6b13cdad170c4674a061b9ff69847164',  
        'description': '',  
        'dns\_nameservers': <objectobjectat0x7f24c067a3a0>,  
        'ipv6\_ra\_mode': <objectobjectat0x7f24c067a3a0>,  
        'allocation\_pools': <objectobjectat0x7f24c067a3a0>,  
        u'gateway\_ip': u'10.10.10.1',  
        u'ip\_version': 4,  
        'ipv6\_address\_mode': <objectobjectat0x7f24c067a3a0>,  
        u'cidr': u'10.10.10.0/24',  
        'subnetpool\_id': <objectobjectat0x7f24c067a3a0>,  
        'use\_default\_subnetpool': False  
    \}  
\}

action为： create\_subnet

同样需要经过Ml2Plugin.create\_subnet方法

def create_subnet(self, context, subnet):
        result, mech_context = self._create_subnet_db(context, subnet)
        try:
            self.mechanism_manager.create_subnet_postcommit(mech_context)
        except ml2_exc.MechanismDriverError:
            with excutils.save_and_reraise_exception():
                LOG.error(_LE("mechanism_manager.create_subnet_postcommit " "failed, deleting subnet '%s'"), result['id'])
                self.delete_subnet(context, result['id'])
        return result

def _create_subnet_db(self, context, subnet): session = context.session with session.begin(subtransactions=True): result = super(Ml2Plugin, self).create_subnet(context, subnet) self.extension_manager.process_create_subnet( context, subnet[attributes.SUBNET], result) network = self.get_network(context, result['network_id']) mech_context = driver_context.SubnetContext(self, context, result, network) self.mechanism_manager.create_subnet_precommit(mech_context) return result, mech_context

调用db/db\_base\_plugin\_v2.py中create\_subnet函数：

def create_subnet(self, context, subnet):
    
        s = subnet['subnet']
        cidr = s.get('cidr', attributes.ATTR_NOT_SPECIFIED)
        prefixlen = s.get('prefixlen', attributes.ATTR_NOT_SPECIFIED)
        has_cidr = attributes.is_attr_set(cidr)
        has_prefixlen = attributes.is_attr_set(prefixlen)
    
        if has_cidr and has_prefixlen:
            msg = _('cidr and prefixlen must not be supplied together')
            raise n_exc.BadRequest(resource='subnets', msg=msg)
    
        if has_cidr:
            # turn the CIDR into a proper subnet net = netaddr.IPNetwork(s['cidr'])
            subnet['subnet']['cidr'] = '%s/%s' % (net.network, net.prefixlen)
    
        subnetpool_id = self._get_subnetpool_id(context, s)
        if not subnetpool_id and not has_cidr:
            msg = _('a subnetpool must be specified in the absence of a cidr')
            raise n_exc.BadRequest(resource='subnets', msg=msg)
    
        if subnetpool_id:
            self.ipam.validate_pools_with_subnetpool(s)
            if subnetpool_id == constants.IPV6_PD_POOL_ID:
                if has_cidr:
                    # We do not currently support requesting a specific # cidr with IPv6 prefix delegation. Set the subnetpool_id # to None and allow the request to continue as normal. subnetpool_id = None self._validate_subnet(context, s)
                else:
                    prefix = constants.PROVISIONAL_IPV6_PD_PREFIX
                    subnet['subnet']['cidr'] = prefix
                    self._validate_subnet_for_pd(s)
        else:
            if not has_cidr:
                msg = _('A cidr must be specified in the absence of a ' 'subnet pool')
                raise n_exc.BadRequest(resource='subnets', msg=msg)
            self._validate_subnet(context, s)
    
        return self._create_subnet(context, subnet, subnetpool_id)

分配子网，并存入数据库

##     ##

## 3. port源码分析 ##

创建一个特定ip地址的Openstack网络端口， 通过执行命令:

neutron port-create --fixed-ip subnet\_id=90cf42a5-61e5-4684-a9a3-ed241f8a00fb,ip\_address=10.10.10.10 01978067-94f2-4758-b124-b33413a9d9f2

![Image 1][]

neutron.api.v2.base中create函数中body大致如下：

\{  
    u'port': \{  
        'binding: host\_id': <objectobjectat0x7f88073b63a0>,  
        'description': '',  
        'allowed\_address\_pairs': <objectobjectat0x7f88073b63a0>,  
        u'admin\_state\_up': True,  
        u'network\_id': u'01978067-94f2-4758-b124-b33413a9d9f2',  
        'tenant\_id': u'6b13cdad170c4674a061b9ff69847164',  
        'extra\_dhcp\_opts': None,  
        'mac\_address': <objectobjectat0x7f88073b63a0>,  
        'name': '',  
        'device\_owner': '',  
        'device\_id': '',  
        'dns\_name': '',  
        'binding: profile': <objectobjectat0x7f88073b63a0>,  
        'port\_security\_enabled': <objectobjectat0x7f88073b63a0>,  
        'binding: vnic\_type': 'normal',  
        u'fixed\_ips': \[  
            \{  
                u'subnet\_id': u'90cf42a5-61e5-4684-a9a3-ed241f8a00fb',  
                u'ip\_address': u'10.10.10.10'  
            \}  
        \],  
        'security\_groups': <objectobjectat0x7f88073b63a0>,  
        'qos\_policy\_id': None  
    \}  
\}

def create_port(self, context, port): # TODO(kevinbenton): remove when bug/1543094 is fixed. with lockutils.lock(port['port']['network_id'], lock_file_prefix='neutron-create-port', external=True): result, mech_context = self._create_port_db(context, port) # notify any plugin that is interested in port create events kwargs = { 'context': context, 'port': result} registry.notify(resources.PORT, events.AFTER_CREATE, self, **kwargs) try: self.mechanism_manager.create_port_postcommit(mech_context) self.notify_security_groups_member_updated(context, result) try: bound_context = self._bind_port_if_needed(mech_context) return bound_context.current

def _create_port_db(self, context, port):
        attrs = port[attributes.PORT]
        if not attrs.get('status'):
            attrs['status'] = const.PORT_STATUS_DOWN
    
        session = context.session
        with db_api.exc_to_retry(os_db_exception.DBDuplicateEntry),\
                session.begin(subtransactions=True):
            dhcp_opts = attrs.get(edo_ext.EXTRADHCPOPTS, [])
            port_db = self.create_port_db(context, port)
            result = self._make_port_dict(port_db, process_extensions=False)
            self.extension_manager.process_create_port(context, attrs, result)
            self._portsec_ext_port_create_processing(context, result, port)
    
            # sgids must be got after portsec checked with security group sgids = self._get_security_groups_on_port(context, port)
            self._process_port_create_security_group(context, result, sgids)
            network = self.get_network(context, result['network_id'])
            binding = db.add_port_binding(session, result['id'])
            mech_context = driver_context.PortContext(self, context, result, network, binding, None)
            self._process_port_binding(mech_context, attrs)
    
            result[addr_pair.ADDRESS_PAIRS] = (
                self._process_create_allowed_address_pairs(
                    context, result, attrs.get(addr_pair.ADDRESS_PAIRS)))
            self._process_port_create_extra_dhcp_opts(context, result, dhcp_opts)
            self.mechanism_manager.create_port_precommit(mech_context)
    
        self._apply_dict_extend_functions('ports', result, port_db)
        return result, mech_context

该代码主要调用Ml2Plugin的create\_port创建port以及为port分配MAC和IP，同时更新neutron中相关的数据库信息

def add_port_binding(session, port_id):
        with session.begin(subtransactions=True):
            record = models.PortBinding(
                port_id=port_id, vif_type=portbindings.VIF_TYPE_UNBOUND)
            session.add(record)
            return record

add\_port\_binding函数写入数据库ml2\_port\_bindings中vif\_type为unbound

## 3.1 IP分配 ##

def _allocate_ips_for_port(self, context, port): """Allocate IP addresses for the port. If port['fixed_ips'] is set to 'ATTR_NOT_SPECIFIED', allocate IP addresses for the port. If port['fixed_ips'] contains an IP address or a subnet_id then allocate an IP address accordingly. """ p = port['port'] ips = [] v6_stateless = [] net_id_filter = { 'network_id': [p['network_id']]} subnets = self._get_subnets(context, filters=net_id_filter) is_router_port = ( p['device_owner'] in constants.ROUTER_INTERFACE_OWNERS_SNAT) fixed_configured = p['fixed_ips'] is not attributes.ATTR_NOT_SPECIFIED if fixed_configured: configured_ips = self._test_fixed_ips_for_port(context, p["network_id"], p['fixed_ips'], p['device_owner']) ips = self._allocate_fixed_ips(context, configured_ips, p['mac_address']) # For ports that are not router ports, implicitly include all # auto-address subnets for address association. if not is_router_port: v6_stateless += [subnet for subnet in subnets if ipv6_utils.is_auto_address_subnet(subnet)]

def _allocate_fixed_ips(self, context, fixed_ips, mac_address):
        """Allocate IP addresses according to the configured fixed_ips.""" ips = []
    
        # we need to start with entries that asked for a specific IP in case # those IPs happen to be next in the line for allocation for ones that # didn't ask for a specific IP fixed_ips.sort(key=lambda x: 'ip_address' not in x)
        for fixed in fixed_ips:
            subnet = self._get_subnet(context, fixed['subnet_id'])
            is_auto_addr = ipv6_utils.is_auto_address_subnet(subnet)
            if 'ip_address' in fixed:
                if not is_auto_addr:
                    # Remove the IP address from the allocation pool IpamNonPluggableBackend._allocate_specific_ip(
                        context, fixed['subnet_id'], fixed['ip_address'])
                ips.append({
         'ip_address': fixed['ip_address'], 'subnet_id': fixed['subnet_id']})
            # Only subnet ID is specified => need to generate IP # from subnet else:
                if is_auto_addr:
                    ip_address = self._calculate_ipv6_eui64_addr(context, subnet, mac_address)
                    ips.append({
         'ip_address': ip_address.format(), 'subnet_id': subnet['id']})
                else:
                    subnets = [subnet]
                    # IP address allocation result = self._generate_ip(context, subnets)
                    ips.append({
         'ip_address': result['ip_address'], 'subnet_id': result['subnet_id']})
        return ips

根据network\_id找到subnets(可能一个network有多个subnet)，然后判断fixed ip。如果指定了fixed ip，则验证fixed ip在该network下是否合法，否则直接利用subnet下的可用ip分配。

*  指定了subnet和fixed IP，执行NeutronDbPluginV2.\_allocate\_specific\_ip
 *  指定了subnet，未指定fixed IP，执行self.\_generate\_ip代码

主要是查询neutron数据库中的ipavailabilityranges表获取IP的范围，然后分配IP后，更新ipavailabilityranges表。

\[neutron\]> SELECT  \* FROM ipavailabilityranges;  
\+--------------------------------------+----------------+----------------+  
| allocation\_pool\_id                   | first\_ip       | last\_ip        |  
\+--------------------------------------+----------------+----------------+  
| a5818bca-e7b5-4399-a405-a6a095800281 | 10.10.10.11    | 10.10.10.254   |  
| a5818bca-e7b5-4399-a405-a6a095800281 | 10.10.10.2      | 10.10.10.9     |

IP分配完毕后，则将被分配了的IP更到neutron数据库的ipallocations表。

\[neutron\]> SELECT \* FROM ipallocations;  
\+--------------------------------------+----------------+--------------------------------------+--------------------------------------+  
| port\_id                                    | ip\_address     | subnet\_id                            | network\_id                           |  
\+--------------------------------------+----------------+--------------------------------------+--------------------------------------+  
| 07130e1c-a6d4-4f28-843c-33b1e07b223e | 10.248.144.102 | 5eb54ff1-25a7-4ffd-87c8-99e492701f15 | c4206574-8125-41e6-be09-5a624dadb570 |  
| dba288c4-3c63-4af3-87fc-929166d072e6 | 10.10.10.10    | 90cf42a5-61e5-4684-a9a3-ed241f8a00fb | 01978067-94f2-4758-b124-b33413a9d9f2 |  
\+--------------------------------------+----------------+--------------------------------------+--------------------------------------+

**创建VM时，从neutron-dhcp-agent获取ip和mac**：

1. 创建VM时，nova-compute与neutron的plugin交互，在数据库中创建VM的port。

2. neutron数据库中的port创建后，通知neutron-dhcp-agent执行port\_create\_end。将数据库中port的ip和mac写入到dnsmasq配置文件中(包括host和addn\_hosts)。

3. VM启动时，广播dhcp discover请求，当dnsmasq进程的监听接口接收这种请求时，dnsmasq进程将根据配置文件(host和leases文件)中的内容去判定是否有未分配的ip和mac为其提供。

4. VM便获取到与保存在数据库中的ip和mac信息。neutron-dhcp-agent只是将所创建VM的ip和mac信息从数据库中获取到自己的配置文件中，然后等到VM启动时，为其提供。

[Image 1]: