firewall

Documentation

Overview

Package firewall provides firewall service to the caller

Index

• Constants
• Variables
• func NewError(err error) error
• type Agent
• type ConnectionState
• type ConnectionStates
  • func (c ConnectionStates) Equal(other ConnectionStates) bool
• type Direction
• type Error
  • func (e *Error) Error() string
  • func (e *Error) Unwrap() error
• type Firewall
  • func NewFirewall(noop, working Agent, publisher events.Publisher[string], enabled bool) *Firewall
  • func (fw *Firewall) Add(rules []Rule) error
  • func (fw *Firewall) Delete(names []string) error
  • func (fw *Firewall) Disable() error
  • func (fw *Firewall) Enable() error
  • func (fw *Firewall) Flush() error
• type FirewallManager
  • func NewFirewallManager(devices device.ListFunc, cmdRunner iptablesmanager.CommandRunner, ...) FirewallManager
  • func (f *FirewallManager) APIAllowlist() error
  • func (f *FirewallManager) APIDenylist() error
  • func (f *FirewallManager) AllowFileshare(peer meshnet.UniqueAddress) error
  • func (f *FirewallManager) AllowIncoming(peer meshnet.UniqueAddress, allowLocal bool) error
  • func (f *FirewallManager) BlockTraffic() error
  • func (f *FirewallManager) DenyFileshare(peerUID string) error
  • func (f *FirewallManager) DenyIncoming(peerUID string) error
  • func (f *FirewallManager) SetAllowlist(udpPorts []int, tcpPorts []int, subnets []netip.Prefix) error
  • func (f *FirewallManager) UnblockTraffic() error
  • func (f *FirewallManager) UnsetAllowlist() error
• type OrderedRules
  • func (or *OrderedRules) Add(rule Rule) error
  • func (or *OrderedRules) Delete(name string) error
  • func (or *OrderedRules) Get(name string) (Rule, error)
• type PortRange
• type PortsDirection
• type Rule
  • func (r Rule) Equal(other Rule) bool
• type Service

Constants

const (
	TrafficBlock iptablesmanager.RulePriority = iota
	ApiAllowlistMark
	ApiAllowlistOutputConnmark
	UserAllowlist
	MeshnetFileshare
	MeshnetIncoming
	MeshnetBlockIncomingLAN
)

Variables

var (
	// ErrRuleNotFound defines that rule was not found in the firewall
	ErrRuleNotFound = fmt.Errorf("rule with specified name does not exist")
	// ErrRuleAlreadyExists defines that rule with specified name or parameters already exists
	ErrRuleAlreadyExists = fmt.Errorf("rule with specified name already exists")
	// ErrRuleWithoutName is returned when provided firewall rule does not have a name
	ErrRuleWithoutName = fmt.Errorf("rule must have a name")
	// ErrFirewallAlreadyEnabled defines that enable was called twice in a row
	ErrFirewallAlreadyEnabled = fmt.Errorf("firewall is already enabled")
	// ErrFirewallAlreadyDisabled defines that disable was called twice in a row
	ErrFirewallAlreadyDisabled = fmt.Errorf("firewall is already disabled")
)

var (
	ErrRuleAlreadyActive = errors.New("rule is already active")
	ErrRuleNotActive     = errors.New("rule does not exist")
)

Functions

func NewError

func NewError(err error) error

Types

type Agent

type Agent interface {
	// Add a firewall rule
	Add(Rule) error
	// Delete a firewall rule
	Delete(Rule) error
	// Flush removes all nordvpn rules
	Flush() error
}

Agent carries out required firewall changes.

Used by implementers.

type ConnectionState

type ConnectionState int

ConnectionState defines a state of a connection

const (
	// Established means that packet is associated with a connection
	Established ConnectionState = iota
	// Related means that packet creates a new connection, but it is related with the existing one
	Related
	// New means that packet creates a new connection
	New
)

type ConnectionStates

type ConnectionStates struct {
	SrcAddr netip.Addr
	States  []ConnectionState
}

func (ConnectionStates) Equal

func (c ConnectionStates) Equal(other ConnectionStates) bool

type Direction

type Direction int

Direction defines a direction of packages to which rule is applicable

const (
	// Inbound defines that rule is applicable for incoming packets
	Inbound Direction = iota
	// Outbound defines that rule is applicable for outgoing packets
	Outbound
	// TwoWay defines that rule is applicable for both incoming and outgoing packets
	TwoWay
	// Forward new case, as Firewall does not only In/Out but also Forwarding control
	Forward
)

type Error

type Error struct {
	// contains filtered or unexported fields
}

Error marks that it originated in firewall package

func (*Error) Error

func (e *Error) Error() string

func (*Error) Unwrap

func (e *Error) Unwrap() error

type Firewall

type Firewall struct {
	// contains filtered or unexported fields
}

Firewall is responsible for correctly changing one firewall agent over another.

Thread-safe.

func NewFirewall

func NewFirewall(noop, working Agent, publisher events.Publisher[string], enabled bool) *Firewall

NewFirewall produces an instance of Firewall.

func (*Firewall) Add

func (fw *Firewall) Add(rules []Rule) error

Add rules to the firewall.

func (*Firewall) Delete

func (fw *Firewall) Delete(names []string) error

Delete rules from firewall by their names.

func (*Firewall) Disable

func (fw *Firewall) Disable() error

Disable turns all firewall operations into no-ops.

func (*Firewall) Enable

func (fw *Firewall) Enable() error

Enable restores firewall operations from no-ops.

func (*Firewall) Flush

func (fw *Firewall) Flush() error

type FirewallManager

type FirewallManager struct {
	// contains filtered or unexported fields
}

func NewFirewallManager

func NewFirewallManager(devices device.ListFunc,
	cmdRunner iptablesmanager.CommandRunner,
	connmark uint32,
	ip6TablesSupported bool,
	enabled bool) FirewallManager

func (*FirewallManager) APIAllowlist

func (f *FirewallManager) APIAllowlist() error

APIAllowlist adds ACCEPT rules for privileged traffic, for each interface.

func (*FirewallManager) APIDenylist

func (f *FirewallManager) APIDenylist() error

ApiDenylis removes ACCEPT rules added by ApiAllowlist.

func (*FirewallManager) AllowFileshare

func (f *FirewallManager) AllowFileshare(peer meshnet.UniqueAddress) error

AllowFileshare adds ACCEPT rule for all incoming connections to tcp port 49111 from the peer with given UniqueAddress.

func (*FirewallManager) AllowIncoming

func (f *FirewallManager) AllowIncoming(peer meshnet.UniqueAddress, allowLocal bool) error

func (*FirewallManager) BlockTraffic

func (f *FirewallManager) BlockTraffic() error

BlocTraffic adds DROP rules for all the incoming traffic, for every viable network interface

func (*FirewallManager) DenyFileshare

func (f *FirewallManager) DenyFileshare(peerUID string) error

DenyFileshare removes ACCEPT rule for all incoming connections to tcp port 49111 from the peer with given UniqueAddress.

func (*FirewallManager) DenyIncoming

func (f *FirewallManager) DenyIncoming(peerUID string) error

func (*FirewallManager) SetAllowlist

func (f *FirewallManager) SetAllowlist(udpPorts []int, tcpPorts []int, subnets []netip.Prefix) error

SetAllowlist adds allowlist rules for the given udpPorts, tcpPorts and subnets.

func (*FirewallManager) UnblockTraffic

func (f *FirewallManager) UnblockTraffic() error

UnblockTraffic removes DROP rules added by BlockTraffic. Returns an error if BlockTraffic was not previously called.

func (*FirewallManager) UnsetAllowlist

func (f *FirewallManager) UnsetAllowlist() error

UnsetAllowlist removes all the rules added by SetAllowlist.

type OrderedRules

type OrderedRules struct {
	// contains filtered or unexported fields
}

OrderedRules stores rules in an order they were added.

func (*OrderedRules) Add

func (or *OrderedRules) Add(rule Rule) error

func (*OrderedRules) Delete

func (or *OrderedRules) Delete(name string) error

Delete rule by name if found.

func (*OrderedRules) Get

func (or *OrderedRules) Get(name string) (Rule, error)

type PortRange

type PortRange struct {
	// contains filtered or unexported fields
}

type PortsDirection

type PortsDirection int

PortsDirection represents direction in which ports are open to, source, destination or both

const (
	SourceAndDestination PortsDirection = iota
	Destination
	Source
)

type Rule

type Rule struct {
	// Name of the firewall rule
	Name string `json:"name"`
	// Interfaces define a list of network interfaces to which rule is applicable
	Interfaces []net.Interface `json:"interfaces"`
	// Networks is a list of IP networks to which rule is applicable
	RemoteNetworks []netip.Prefix `json:"remote_networks"`
	LocalNetworks  []netip.Prefix `json:"local_networks"`

	// Ports is a list of ports to which rule is applicable
	Ports []int `json:"ports"`
	// PortsDirection is a direction that ports are open to
	PortsDirection PortsDirection
	// Protocols is a list of protocol string values to which rule is applicable
	Protocols []string `json:"protocols"`
	// Direction defines to which packets rule is applicable
	Direction Direction `json:"direction"`
	// ConnectionStates defines to which connection states rule is applicable
	ConnectionStates ConnectionStates `json:"connection_states"`
	// Marks defines that packets marked with any of the marks are
	// affected by the firewall rule
	Marks []uint32
	// Allow defines if rule denies packets via current rule or allows them
	Allow bool `json:"allow"`

	Ipv6Only         bool   `json:"ipv6_only"`
	Icmpv6Types      []int  `json:"icmp6_types"`
	HopLimit         uint8  `json:"hop_limit"`
	SourcePorts      []int  `json:"source_ports"`
	DestinationPorts []int  `json:"destination_ports"`
	Comment          string `json:"comment"`
}

Rule defines a single firewall rule which is applicable for set of addresses, ports and protocols

func (Rule) Equal

func (r Rule) Equal(other Rule) bool

type Service

type Service interface {
	// Add and apply firewall rules
	Add([]Rule) error
	// Delete a list of firewall rules by defined names
	Delete(names []string) error
	// Enable firewall
	Enable() error
	// Disable firewall
	Disable() error
	// Flushes firewall
	Flush() error
}

Service adapts system firewall configuration to firewall rules

Used by callers.