Documentation

Overview

    The subnets package provides a subnet pool from which networks may be dynamically acquired or statically reserved.

    Index

    Constants

    This section is empty.

    Variables

    View Source
    var (
    	// ErrInsufficientSubnets is returned by AcquireDynamically if no more subnets can be allocated.
    	ErrInsufficientSubnets = errors.New("insufficient subnets remaining in the pool")
    
    	// ErrInsufficientIPs is returned by AcquireDynamically if no more IPs can be allocated.
    	ErrInsufficientIPs = errors.New("insufficient IPs remaining in the pool")
    
    	// ErrReleasedUnallocatedNetwork is returned by Release if the subnet is not allocated.
    	ErrReleasedUnallocatedSubnet = errors.New("subnet is not allocated")
    
    	// ErrOverlapsExistingSubnet is returned if a recovered subnet overlaps an existing, allocated subnet
    	ErrOverlapsExistingSubnet = errors.New("subnet overlaps an existing subnet")
    
    	// ErrInvalidRange is returned by AcquireStatically and by Recover if the subnet range is invalid.
    	ErrInvalidRange = errors.New("subnet has invalid range")
    
    	// ErrInvalidIP is returned if a static IP is requested inside a subnet
    	// which does not contain that IP
    	ErrInvalidIP = errors.New("the requested IP is not within the subnet")
    
    	// ErrIPAlreadyAcquired is returned if a static IP is requested which has already been allocated
    	ErrIPAlreadyAcquired = errors.New("the requested IP is already allocated")
    
    	// ErrIpCannotBeNil is returned by Release(..) and Recover(..) if a nil
    	// IP address is passed.
    	ErrIpCannotBeNil = errors.New("the IP field cannot be empty")
    
    	ErrIPEqualsGateway   = errors.New("a container IP must not equal the gateway IP")
    	ErrIPEqualsBroadcast = errors.New("a container IP must not equal the broadcast IP")
    )
    View Source
    var DynamicIPSelector dynamicIPSelector = 0

      DynamicIPSelector requests the next available ("dynamic") IP address from a given subnet. Returns an error if no more IP addresses remain in the subnet.

      View Source
      var DynamicSubnetSelector dynamicSubnetSelector = 0

        DynamicSubnetSelector requests the next unallocated ("dynamic") subnet from the dynamic range. Returns an error if there are no remaining subnets in the dynamic range.

        Functions

        func BroadcastIP

        func BroadcastIP(subnet *net.IPNet) net.IP

          Returns the broadcast IP of a subnet.

          func GatewayIP

          func GatewayIP(subnet *net.IPNet) net.IP

            Returns the gateway IP of a given subnet, which is always the maximum valid IP

            func NetworkIP

            func NetworkIP(subnet *net.IPNet) net.IP

              Returns the network IP of a subnet.

              Types

              type IPSelector

              type IPSelector interface {
              	// Returns an IP address in the given subnet which is not one of the given existing
              	// IP addresses. If no such IP address can be found, returns an error.
              	SelectIP(subnet *net.IPNet, existing []net.IP) (net.IP, error)
              }

                IPSelector is a strategy for selecting an IP address in a subnet.

                type Pool

                type Pool interface {
                	// Allocates an IP address and associates it with a subnet. The subnet is selected by the given SubnetSelector.
                	// The IP address is selected by the given IPSelector.
                	// Returns a subnet, an IP address, and if either selector fails, an error is returned.
                	Acquire(lager.Logger, SubnetSelector, IPSelector) (*net.IPNet, net.IP, error)
                
                	// Releases an IP address associated with an allocated subnet. If the subnet has no other IP
                	// addresses associated with it, it is deallocated.
                	// Returns an error if the given combination is not already in the pool.
                	Release(*net.IPNet, net.IP) error
                
                	// Remove an IP address so it appears to be associated with the given subnet.
                	Remove(*net.IPNet, net.IP) error
                
                	// Returns the number of /30 subnets which can be Acquired by a DynamicSubnetSelector.
                	Capacity() int
                
                	// Run the provided callback if the given subnet is not in use
                	RunIfFree(*net.IPNet, func() error) error
                }

                func NewPool

                func NewPool(ipNet *net.IPNet) Pool

                type StaticIPSelector

                type StaticIPSelector struct {
                	net.IP
                }

                  StaticIPSelector requests a specific ("static") IP address. Returns an error if the IP is already allocated, or if it is outside the given subnet.

                  func (StaticIPSelector) SelectIP

                  func (s StaticIPSelector) SelectIP(subnet *net.IPNet, existing []net.IP) (net.IP, error)

                  type StaticSubnetSelector

                  type StaticSubnetSelector struct {
                  	*net.IPNet
                  }

                    StaticSubnetSelector requests a specific ("static") subnet. Returns an error if the subnet is already allocated.

                    func (StaticSubnetSelector) SelectSubnet

                    func (s StaticSubnetSelector) SelectSubnet(dynamic *net.IPNet, existing []*net.IPNet) (*net.IPNet, error)

                    type SubnetSelector

                    type SubnetSelector interface {
                    	// Returns a subnet based on a dynamic range and some existing statically-allocated
                    	// subnets. If no suitable subnet can be found, returns an error.
                    	SelectSubnet(dynamic *net.IPNet, existing []*net.IPNet) (*net.IPNet, error)
                    }

                      SubnetSelector is a strategy for selecting a subnet.

                      Directories

                      Path Synopsis
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