netstack2

package
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 Go to latest Published: Mar 4, 2026 License: AGPL-3.0 Imports: 36 Imported by: 0

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Constants

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Variables

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Functions

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Types

type ICMPHandler 

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

ICMPHandler handles ICMP packets from netstack

func NewICMPHandler 

func NewICMPHandler(s *stack.Stack, ph *ProxyHandler) *ICMPHandler

NewICMPHandler creates a new ICMP handler

func (*ICMPHandler) InstallICMPHandler 

func (h *ICMPHandler) InstallICMPHandler() error

InstallICMPHandler installs the ICMP handler on the stack

type Net 

type Net netTun

func CreateNetTUN 

func CreateNetTUN(localAddresses, dnsServers []netip.Addr, mtu int) (tun.Device, *Net, error)

CreateNetTUN creates a new TUN device with netstack without proxying

func CreateNetTUNWithOptions 

func CreateNetTUNWithOptions(localAddresses, dnsServers []netip.Addr, mtu int, options NetTunOptions) (tun.Device, *Net, error)

CreateNetTUNWithOptions creates a new TUN device with netstack and optional TCP/UDP proxying

func (*Net) AddProxySubnetRule 

func (net *Net) AddProxySubnetRule(sourcePrefix, destPrefix netip.Prefix, rewriteTo string, portRanges []PortRange, disableIcmp bool)

AddProxySubnetRule adds a subnet rule to the proxy handler If portRanges is nil or empty, all ports are allowed for this subnet rewriteTo can be either an IP/CIDR (e.g., "192.168.1.1/32") or a domain name (e.g., "example.com")

func (*Net) Dial 

func (tnet *Net) Dial(network, address string) (net.Conn, error)

func (*Net) DialContext 

func (tnet *Net) DialContext(ctx context.Context, network, address string) (net.Conn, error)

func (*Net) DialContextTCP 

func (net *Net) DialContextTCP(ctx context.Context, addr *net.TCPAddr) (*gonet.TCPConn, error)

func (*Net) DialContextTCPAddrPort 

func (net *Net) DialContextTCPAddrPort(ctx context.Context, addr netip.AddrPort) (*gonet.TCPConn, error)

func (*Net) DialPing 

func (net *Net) DialPing(laddr, raddr *PingAddr) (*PingConn, error)

func (*Net) DialPingAddr 

func (net *Net) DialPingAddr(laddr, raddr netip.Addr) (*PingConn, error)

func (*Net) DialTCP 

func (net *Net) DialTCP(addr *net.TCPAddr) (*gonet.TCPConn, error)

func (*Net) DialTCPAddrPort 

func (net *Net) DialTCPAddrPort(addr netip.AddrPort) (*gonet.TCPConn, error)

func (*Net) DialUDP 

func (net *Net) DialUDP(laddr, raddr *net.UDPAddr) (*gonet.UDPConn, error)

func (*Net) DialUDPAddrPort 

func (net *Net) DialUDPAddrPort(laddr, raddr netip.AddrPort) (*gonet.UDPConn, error)

func (*Net) GetProxyHandler 

func (net *Net) GetProxyHandler() *ProxyHandler

GetProxyHandler returns the proxy handler (for advanced use cases) Returns nil if proxy is not enabled

func (*Net) ListenPing 

func (net *Net) ListenPing(laddr *PingAddr) (*PingConn, error)

func (*Net) ListenPingAddr 

func (net *Net) ListenPingAddr(laddr netip.Addr) (*PingConn, error)

func (*Net) ListenTCP 

func (net *Net) ListenTCP(addr *net.TCPAddr) (*gonet.TCPListener, error)

func (*Net) ListenTCPAddrPort 

func (net *Net) ListenTCPAddrPort(addr netip.AddrPort) (*gonet.TCPListener, error)

func (*Net) ListenUDP 

func (net *Net) ListenUDP(laddr *net.UDPAddr) (*gonet.UDPConn, error)

func (*Net) ListenUDPAddrPort 

func (net *Net) ListenUDPAddrPort(laddr netip.AddrPort) (*gonet.UDPConn, error)

func (*Net) LookupContextHost 

func (tnet *Net) LookupContextHost(ctx context.Context, host string) ([]string, error)

func (*Net) LookupHost 

func (net *Net) LookupHost(host string) (addrs []string, err error)

func (*Net) RemoveProxySubnetRule 

func (net *Net) RemoveProxySubnetRule(sourcePrefix, destPrefix netip.Prefix)

RemoveProxySubnetRule removes a subnet rule from the proxy handler

type NetTunOptions 

type NetTunOptions struct {
	EnableTCPProxy  bool
	EnableUDPProxy  bool
	EnableICMPProxy bool
}

NetTunOptions contains options for creating a NetTUN device

type PingAddr 

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

func PingAddrFromAddr 

func PingAddrFromAddr(addr netip.Addr) *PingAddr

func (PingAddr) Addr 

func (ia PingAddr) Addr() netip.Addr

func (PingAddr) Network 

func (ia PingAddr) Network() string

func (PingAddr) String 

func (ia PingAddr) String() string

type PingConn 

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

func (*PingConn) Close 

func (pc *PingConn) Close() error

func (*PingConn) LocalAddr 

func (pc *PingConn) LocalAddr() net.Addr

func (*PingConn) Read 

func (pc *PingConn) Read(p []byte) (n int, err error)

func (*PingConn) ReadFrom 

func (pc *PingConn) ReadFrom(p []byte) (n int, addr net.Addr, err error)

func (*PingConn) RemoteAddr 

func (pc *PingConn) RemoteAddr() net.Addr

func (*PingConn) SetDeadline 

func (pc *PingConn) SetDeadline(t time.Time) error

func (*PingConn) SetReadDeadline 

func (pc *PingConn) SetReadDeadline(t time.Time) error

func (*PingConn) SetWriteDeadline 

func (pc *PingConn) SetWriteDeadline(t time.Time) error

func (*PingConn) Write 

func (pc *PingConn) Write(p []byte) (n int, err error)

func (*PingConn) WriteTo 

func (pc *PingConn) WriteTo(p []byte, addr net.Addr) (n int, err error)

type PortRange 

type PortRange struct {
	Min      uint16
	Max      uint16
	Protocol string // "tcp", "udp", or "" for both
}

PortRange represents an allowed range of ports (inclusive) with optional protocol filtering Protocol can be "tcp", "udp", or "" (empty string means both protocols)

type ProxyHandler 

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

ProxyHandler handles packet injection and extraction for promiscuous mode

func NewProxyHandler 

func NewProxyHandler(options ProxyHandlerOptions) (*ProxyHandler, error)

NewProxyHandler creates a new proxy handler for promiscuous mode

func (*ProxyHandler) AddSubnetRule 

func (p *ProxyHandler) AddSubnetRule(sourcePrefix, destPrefix netip.Prefix, rewriteTo string, portRanges []PortRange, disableIcmp bool)

AddSubnetRule adds a subnet with optional port restrictions to the proxy handler sourcePrefix: The IP prefix of the peer sending the data destPrefix: The IP prefix of the destination rewriteTo: Optional address to rewrite destination to - can be IP/CIDR or domain name If portRanges is nil or empty, all ports are allowed for this subnet

func (*ProxyHandler) Close 

func (p *ProxyHandler) Close() error

Close cleans up the proxy handler resources

func (*ProxyHandler) HandleIncomingPacket 

func (p *ProxyHandler) HandleIncomingPacket(packet []byte) bool

HandleIncomingPacket processes incoming packets and determines if they should be injected into the proxy stack

func (*ProxyHandler) Initialize 

func (p *ProxyHandler) Initialize(notifiable channel.Notification) error

Initialize sets up the promiscuous NIC with the netTun's notification system

func (*ProxyHandler) LookupDestinationRewrite 

func (p *ProxyHandler) LookupDestinationRewrite(srcIP, dstIP string, dstPort uint16, proto uint8) (netip.Addr, bool)

LookupDestinationRewrite looks up the rewritten destination for a connection This is used by TCP/UDP handlers to find the actual target address

func (*ProxyHandler) QueueICMPReply 

func (p *ProxyHandler) QueueICMPReply(packet []byte) bool

QueueICMPReply queues an ICMP reply packet to be sent back through the tunnel

func (*ProxyHandler) ReadOutgoingPacket 

func (p *ProxyHandler) ReadOutgoingPacket() *buffer.View

ReadOutgoingPacket reads packets from the proxy stack that need to be sent back through the tunnel

func (*ProxyHandler) RemoveSubnetRule 

func (p *ProxyHandler) RemoveSubnetRule(sourcePrefix, destPrefix netip.Prefix)

RemoveSubnetRule removes a subnet from the proxy handler

type ProxyHandlerOptions 

type ProxyHandlerOptions struct {
	EnableTCP  bool
	EnableUDP  bool
	EnableICMP bool
	MTU        int
}

ProxyHandlerOptions configures the proxy handler

type SubnetLookup 

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

SubnetLookup provides fast IP subnet and port matching using BART (Binary Aggregated Range Tree) This uses BART Table for O(log n) prefix matching with Supernets() for efficient lookups

Architecture: - Two-level BART structure for matching both source AND destination prefixes - Level 1: Source prefix -> Level 2 (destination prefix -> rules) - This reduces search space: only check destination prefixes for matching source prefixes

func NewSubnetLookup 

func NewSubnetLookup() *SubnetLookup

NewSubnetLookup creates a new subnet lookup table using BART

func (*SubnetLookup) AddSubnet 

func (sl *SubnetLookup) AddSubnet(sourcePrefix, destPrefix netip.Prefix, rewriteTo string, portRanges []PortRange, disableIcmp bool)

AddSubnet adds a subnet rule with source and destination prefixes and optional port restrictions If portRanges is nil or empty, all ports are allowed for this subnet rewriteTo can be either an IP/CIDR (e.g., "192.168.1.1/32") or a domain name (e.g., "example.com")

func (*SubnetLookup) Match 

func (sl *SubnetLookup) Match(srcIP, dstIP netip.Addr, port uint16, proto tcpip.TransportProtocolNumber) *SubnetRule

Match checks if a source IP, destination IP, port, and protocol match any subnet rule Returns the matched rule if ALL of these conditions are met:

  • The source IP is in the rule's source prefix
  • The destination IP is in the rule's destination prefix
  • The port is in an allowed range (or no port restrictions exist)
  • The protocol matches (or the port range allows both protocols)

proto should be header.TCPProtocolNumber, header.UDPProtocolNumber, or header.ICMPv4ProtocolNumber Returns nil if no rule matches This uses BART's Supernets() for O(log n) prefix matching instead of O(n) iteration

func (*SubnetLookup) RemoveSubnet 

func (sl *SubnetLookup) RemoveSubnet(sourcePrefix, destPrefix netip.Prefix)

RemoveSubnet removes a subnet rule from the lookup table

type SubnetRule 

type SubnetRule struct {
	SourcePrefix netip.Prefix // Source IP prefix (who is sending)
	DestPrefix   netip.Prefix // Destination IP prefix (where it's going)
	DisableIcmp  bool         // If true, ICMP traffic is blocked for this subnet
	RewriteTo    string       // Optional rewrite address for DNAT - can be IP/CIDR or domain name
	PortRanges   []PortRange  // empty slice means all ports allowed
}

SubnetRule represents a subnet with optional port restrictions and source address When RewriteTo is set, DNAT (Destination Network Address Translation) is performed:

  • Incoming packets: destination IP is rewritten to the resolved RewriteTo address
  • Outgoing packets: source IP is rewritten back to the original destination

RewriteTo can be either:

  • An IP address with CIDR notation (e.g., "192.168.1.1/32")
  • A domain name (e.g., "example.com") which will be resolved at request time

This allows transparent proxying where traffic appears to come from the rewritten address

type TCPHandler 

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

TCPHandler handles TCP connections from netstack

func NewTCPHandler 

func NewTCPHandler(s *stack.Stack, ph *ProxyHandler) *TCPHandler

NewTCPHandler creates a new TCP handler

func (*TCPHandler) InstallTCPHandler 

func (h *TCPHandler) InstallTCPHandler() error

InstallTCPHandler installs the TCP forwarder on the stack

type UDPHandler 

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

UDPHandler handles UDP connections from netstack

func NewUDPHandler 

func NewUDPHandler(s *stack.Stack, ph *ProxyHandler) *UDPHandler

NewUDPHandler creates a new UDP handler

func (*UDPHandler) InstallUDPHandler 

func (h *UDPHandler) InstallUDPHandler() error

InstallUDPHandler installs the UDP forwarder on the stack

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