Docker Libnetwork Bridge插件实现代码分析----创建网络部分

// drivers/bridge/bridge.go

// Create a new network using bridge plugin

1、func (d *driver) CreateNetwork(id string, option map[string]interface{}, nInfo driverapi.NetworkInfo, ipV4Data, ipV6Data []driverapi.IPAMData) error

  • 首先确定len(ipV4Data)不为0且ipV4Data[0].Pool.String()不为"0.0.0.0/0",否则返回"ipv4 pool is empty"
  • 调用config, err := parseNetworkOptions(id, option)确认配置不和当前的networks的配置矛盾
  • 调用err = config.processIPAM(id, ipV4Data, ipV6Data)
  • 调用err = d.createNetwork(config)进行具体的网络创建
  • 最后调用return d.storeUpdate(config)

// driver/bridge/bridge.go

2、func parseNetworkOptions(id string, option options.Generic) (*networkConfiguration, error)

  • 首先如果option[netlabel.GenericData]不为空,则调用config, err = parseNetworkGenericOptions(genData)先解析generic label
  • 再对well-known labels进行处理,例如config.EnableIPv6和config.Internal
  • 若config.BridgeName为"",并且config.DefaultBridge为false,则默认创建config.BridgeName = "br-" + id[:12]
  • 之后再调用exists, err := bridgeInterfaceExists(config.BridgeName),若不存在则config.BridgeIfaceCreator = ifaceCreatedByLibnetwork,否则为ifaceCreatedByUser

networkConfiguraion数据结构如下所示

// networkConfiguraion for network specific configuraion
type networkConfiguraion struct {
  ID          string
  BridgeName     string
  EnableIPv6      bool
  EnableIPMasquerade bool
  EnableICC       bool
  Mtu          int
  DefaultBindingIP    net.IP
  DefaultBridge     bool
  // Internal fields set after ipam data parsing
  AddressIPv4      *net.IPNet
  AddressIPv6      *net.IPNet
  DefaultGatewayIPv4   net.IP
  DefaultGatewayIPv6   net.IP
  dbIndex         uint64
  dbExists         bool
  Internal         bool
  BridgeIfaceCreator    ifaceCreator  // ifaceCreator represents how the bridge interface was created
}

  

// driver/bridge/bridge.go

3、func (c *networkConfiguraion) processIPAM(id string, ipamV4Data, ipamV6Data []driverapi.IPAMData) error

  • 若ipamV4Data[0].Gateway不为nil,则调用c.AddressIPv4 = types.GetIPNetCopy(ipamV4Data[0].Gateway)
  • gw, ok := ipamV4Data[0].AuxAddresses[DefaultGatewayV4AuxKey],若ok为true,则c.DefaultGatewayIPv4为gw.IP
  • 若len(ipamV6Data)大于0,则操作方式和ipamV4Data相同

// driver/bridge/bridge.go

4、func (d *driver) createNetwork(config *networkConfiguraion) error

  • 首先调用networkList := d.getNetworks(),然后再调用for i, nw := range networkList进行遍历
  • 调用nwConfig := nw.config,如果nwConfig.Conflicts(config)返回错误,如果config.DefaultBridge为真,则将nwConfig删除。
  • 创建并且设置一个network handler,network := &bridgeNetwork{},并且将其添加到d.networks[config.ID] = network
  • 如果d.nlh为nil,则调用d.nlh = ns.NlHandle()
  • 调用bridgeIface, err := newInterface(d.nlh, config)创建并且返回the bridge L3 interface,并且将network.bridge = bridgeIface
  • 调用config.conflictsWithNetworks(config.ID, networkList)判断该network configuration 和之前已经安装的networks是否冲突
  • 调用setupNetworkIsolationRules := func(config *networkConfiguration, i *bridgeInterface) error{}
  • 调用bridgeSetup := newBridgeSetup(config, bridgeIface),准备bridge创建的配置,仅仅只是返回一个&bridgeSetup{config: c, bridge: i}的数据结构
  • 调用bridgeAlreadyExists := bridgeIface.exists()判断bridge是否存在,如果不存在则调用bridgeSetup.queueStep(setupDevice)创建设备,即使bridge已经存在了,也调用bridgeSetup.queueStep(setupBridgeIPv4)来设置ip
  • 再利用一个for循环,针对不同的条件,例如config.EnableIPv6,bridgeAlreadyExists等等,调用相应的bridgeSetup.queueStep(step.Fn)
  • 最后调用bridgeSetup.queueStep(setupDeviceUp)和bridgeSetup.apply()

bridgeNetwork数据结构如下所示:

type bridgeNetwork struct {
  id         string
  bridge      *bridgeInterface  // The bridge's L3 interface
  config      *networkConfiguraion
  endpoints     map[string]*bridgeEndpoint // key: endpoint id
  portMapper    *portmapper.PortMapper
  driver       *driver
  iptCleanFuncs   iptablesCleanFuncs
  sync.Mutex
}

bridgeSetup数据结构如下所示:

type bridgeSetup struct {
  config     *networkConfiguraion
  bridge    *bridgeInterface
  steps     []setupStep
  // setupStep是一个函数类型,type setupStep func(*networkConfiguraion, *bridgeInterface) error
  //可以调用queueStep函数往其中添加step,最后调用apply函数遍历执行
}

  

// driver/bridge/interface.go

// newInterface creates a new bridge interface structure. It attempts to find an already existing device

// identified by the configuration BridgeName field, or the default bridge name when unspecified, but

// doesn't attempt to create one when missing

5、func newInterface(nlh *netlink.Handle, config *networkConfiguraion) (*bridgeInterface, error)

  • 首先创建i := &bridgeInterface{nlh: nlh}
  • 若config.BridgeName为"",则将其设置为DefaultBridgeName,即"docker0"
  • 最后调用i.Link, err = nlh.LinkByName(config.BridgeName)查找是否已经存在以该名字命名的网桥

bridgeInterface的数据结构如下所示:

// Interface models the bridge network device

type bridgeInterface struct {

  Link      netlink.Link
  bridgeIPv4   *net.IPNet
  bridgeIPv6   *net.IPNet
  gatewayIPv4   net.IP
  gatewayIPv6   net.IP
  nlh       *netlink.Handle
}

// driver/bridge/setup_device.go

// SetupDevice create a new bridge interface

6、func setupDevice(config *networkConfiguraion, i *bridgeInterface) error

  • 在config.BridgeName != DefaultBridgeName && config.DefaultBridge时退出,两者不兼容
  • 创建i.Link = &netlink.Bridge{LinkAttrs: netlink.LinkAttrs{Name: config.BridgeName,},}
  • 调用kv, err := kernel.GetKernelVersion()获取内核版本,只有在版本大于3.3时,才设置bridge的Mac地址
  • 调用err = i.nlh.LinkAdd(i.Link)创建bridge,若失败,则调用return ioctlCreateBridge(config.BridgeName, setMac)再次创建
  • 若setMac为真,则调用hwAddr := netutils.GenerateRandomMAC()和i.nlh.LinkSetHardwareAddr(i.Link, hwAddr)设置bridge的Mac地址

// driver/bridge/setup_ipv4.go

7、func setupBridgeIPv4(config *networkConfiguraion, i *bridgeInterface) error

  • 调用addrv4List, _, err := i.address()[直接调用i.nlh.AddrList(i.Link, netlink.FAMILY_V4)]和addrv4, _ := selectIPv4Address(addrv4List, config.AddressIPv4)
  • 调用types.CompareIPNet(addrv4.IPNet, config.AddressIPv4),若两者不相等,当addrv4.IPNet不为nil时,调用i.nlh.AddrDel(i.Link, &addrv4)删除该地址,并且调用i.nlh.AddrAdd(i.Link, &netlink.Addr{IPNet: config.AddressIPv4})添加地址
  • 设置i.bridgeIPv4 = config.AddressIPv4,i.gatewayIPv4 = config.AddressIPv4.IP

// driver/bridge/setup_device.go

// SetupDeviceUp ups the given bridge interface

8、func setupDeviceUp(config *networkConfiguraion, i *bridgeInterface) error

  • 该函数仅仅调用err := i.nlh.LinkSetup(i.Link)启动bridge
  • 再调用lnk, err := i.nlh.LinkByName(config.BridgeName)重新获取link,并且将其赋值给i.Link

--------------------------------------------------------- 创建endpoint ----------------------------------------

// drivers/bridge/bridge.go

1、func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo, epOptions map[string]interface{}) error

  • 首先调用n, ok := d.networks[nid], dconfig := d.config获取配置信息
  • 调用epConfig, err := parseEndpointOptions(epOptions)将options转换为endpoint configuraion
  • 调用endpoint := &bridgeEndpoint{id: eid, nid: nid, config: epConfig}和n.endpoints[eid] = endpoint将endpoint加入网络中
  • 创建veth := &netlink.Veth{...}和d.nlh.LinkAdd(veth)添加veth pair
  • 调用addToBridge(d.nlh, hostIfName, config.BridgeName)将host端的veth加入bridge中
  • 将containerIfName,ifInfo.MacAddress(),ifInfo.Address(),info.AddressIPv6信息存储到endpoint中
  • 最后调用d.storeUpdate(endpoint)将endpoint的信息保存起来

bridgeEndpoint数据结构如下所示:

type bridgeEndpoint struct {
  id          string
  nid          string
  srcName       string
  addr         *net.IPNet
  addrv6        *net.IPNet
  macAddress      net.HardwareAddr
  config        *endpointConfiguration // User specified parameters
  containerConfig   *containerConfiguration
  extConnConfig    *connectivityConfiguraion
  portMapping     []types.PortBinding  // Operation port bindings
  dxIndex        uint64
  dbExists        bool
}

  

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