netstack

package
v0.0.0-...-99b537f Latest Latest
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 Go to latest Published: Nov 8, 2024 License: MPL-2.0 Imports: 39 Imported by: 0

Documentation

Overview

Package netstack provides the implemention of data-link layer endpoints backed by boundary-preserving file descriptors (e.g., TUN devices, seqpacket/datagram sockets).

Adopted from: github.com/google/gvisor/blob/f33d034/pkg/tcpip/link/fdbased/endpoint.go since fdbased isn't built when building for android (it is only built for linux).

Index

Constants

View Source 
const (
	// DirectionSend indicates a sent packet.
	DirectionSend = iota
	// DirectionRecv indicates a received packet.
	DirectionRecv
)
View Source 
const SnapLen uint32 = 2048 // in bytes; some sufficient value

SnapLen is the maximum bytes of a packet to be saved. Packets with a length less than or equal to snapLen will be saved in their entirety. Longer packets will be truncated to snapLen.

Variables

View Source 
var BufConfig = []int{128, 256, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768}

BufConfig defines the shape of the vectorised view used to read packets from the NIC.

View Source 
var LogPackets atomicbitops.Uint32 = atomicbitops.FromUint32(0)
View Source 
var WritePCAP atomicbitops.Uint32 = atomicbitops.FromUint32(0)

Functions

func InboundTCP 

func InboundTCP(s *stack.Stack, in net.Conn, to, from netip.AddrPort, h GTCPConnHandler) error

s is the netstack to use for dialing (reads/writes). in is the incoming connection to netstack, s. to (src) is remote. from (dst) is local (to netstack, s). h is the handler that handles connection in into netstack, s, by dialing to from (dst) from to (src).

func InboundUDP 

func InboundUDP(s *stack.Stack, in net.Conn, to, from netip.AddrPort, h GUDPConnHandler) error

func LogFile 

func LogFile(y bool) (ok bool)

func LogPacket 

func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer)

LogPacket logs a packet to stdout.

func LogPcap 

func LogPcap(y bool) (ok bool)

func NewNetstack 

func NewNetstack() (s *stack.Stack)

also: github.com/google/gvisor/blob/adbdac747/runsc/boot/loader.go#L1132 github.com/FlowerWrong/tun2socks/blob/1045a49618/cmd/netstack/main.go github.com/zen-of-proxy/go-tun2io/blob/c08b329b8/tun2io/util.go github.com/WireGuard/wireguard-go/blob/42c9af4/tun/netstack/tun.go github.com/telepresenceio/telepresence/pull/2709

func NewReverseGConnHandler 

func NewReverseGConnHandler(pctx context.Context, to *stack.Stack, of tcpip.NICID, ep stack.LinkEndpoint, via GConnHandler) *gconnhandler

func OutboundICMP 

func OutboundICMP(s *stack.Stack, ep stack.LinkEndpoint, hdl GICMPHandler)

ref: github.com/SagerNet/LibSagerNetCore/blob/632d6b892e/gvisor/icmp.go

func OutboundTCP 

func OutboundTCP(s *stack.Stack, h GTCPConnHandler)

func OutboundUDP 

func OutboundUDP(s *stack.Stack, h GUDPConnHandler)

func Route 

func Route(s *stack.Stack, l3 string)

func SetNetstackOpts 

func SetNetstackOpts(s *stack.Stack)

func StackAddrs 

func StackAddrs(s *stack.Stack, nic tcpip.NICID) (netip.Addr, netip.Addr)

func Stat 

func Stat(s *stack.Stack) (out *x.NetStat, err error)

func Up 

func Up(s *stack.Stack, ep stack.LinkEndpoint, h GConnHandler) (tcpip.NICID, error)

ref: github.com/brewlin/net-protocol/blob/ec64e5f899/internal/endpoint/endpoint.go#L20

func WritePCAPHeader 

func WritePCAPHeader(w io.Writer) error

Types

type DemuxerFn 

type DemuxerFn func(in net.Conn, to netip.AddrPort) error

type Direction 

type Direction int

A Direction indicates whether the packing is being sent or received.

func (Direction) String 

func (dr Direction) String() string

type FdSwapper 

type FdSwapper interface {
	// Swap closes existing FDs; uses new fd and mtu.
	Swap(fd, mtu int) error
	// Dispose closes all existing FDs.
	Dispose() error
}

type GBaseConnHandler 

type GBaseConnHandler interface {
	// OpenConns returns the number of active connections.
	OpenConns() string
	// CloseConns closes conns by ids, or all if ids is empty.
	CloseConns([]string) []string
	// end closes the handler and all its connections.
	End()
}

type GConnHandler 

type GConnHandler interface {
	TCP() GTCPConnHandler         // TCP returns the TCP handler.
	UDP() GUDPConnHandler         // UDP returns the UDP handler.
	ICMP() GICMPHandler           // ICMP returns the ICMP handler.
	CloseConns(csv string) string // CloseConns closes the connections with the given IDs, or all if empty.
}

func NewGConnHandler 

func NewGConnHandler(tcp GTCPConnHandler, udp GUDPConnHandler, icmp GICMPHandler) GConnHandler

type GEchoConnHandler 

type GEchoConnHandler interface {
	// Ping informs if ICMP Echo from src to dst is replied to
	Ping(msg []byte, src, dst netip.AddrPort) bool
}

type GICMPConn 

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

func DialPingAddr 

func DialPingAddr(s *stack.Stack, nic tcpip.NICID, laddr, raddr netip.Addr) (*GICMPConn, error)

func (*GICMPConn) Close 

func (pc *GICMPConn) Close() error

func (*GICMPConn) LocalAddr 

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

func (*GICMPConn) Read 

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

func (*GICMPConn) ReadFrom 

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

func (*GICMPConn) RemoteAddr 

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

func (*GICMPConn) SetDeadline 

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

func (*GICMPConn) SetReadDeadline 

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

func (*GICMPConn) SetWriteDeadline 

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

func (*GICMPConn) Write 

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

func (*GICMPConn) WriteTo 

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

type GICMPHandler 

type GICMPHandler interface {
	GBaseConnHandler
	GEchoConnHandler
}

type GMuxConnHandler 

type GMuxConnHandler[T gconns] interface {
	// ProxyMux proxies data between conn and multiple destinations
	// (endpoint-independent mapping).
	ProxyMux(in T, src, dst netip.AddrPort, dmx DemuxerFn) bool
}

type GSpecConnHandler 

type GSpecConnHandler[T gconns] interface {
	GBaseConnHandler
	// Proxy copies data between conn and dst (egress).
	// must not block forever as it may block netstack
	// see: netstack/dispatcher.go:newReadvDispatcher
	Proxy(in T, src, dst netip.AddrPort) bool
	// ReverseProxy copies data between conn and dst (ingress).
	ReverseProxy(out T, in net.Conn, src, dst netip.AddrPort) bool
	// Error notes the error in connecting src to dst; retrying if necessary.
	Error(in T, src, dst netip.AddrPort, err error)
}

type GTCPConn 

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

func (*GTCPConn) Abort 

func (g *GTCPConn) Abort()

Abort aborts the connection by sending a RST segment.

func (*GTCPConn) Close 

func (g *GTCPConn) Close() error

func (*GTCPConn) CloseRead 

func (g *GTCPConn) CloseRead() error

func (*GTCPConn) CloseWrite 

func (g *GTCPConn) CloseWrite() error

func (*GTCPConn) Establish 

func (g *GTCPConn) Establish() (open bool, err error)

func (*GTCPConn) LocalAddr 

func (g *GTCPConn) LocalAddr() net.Addr

gonet conn local and remote addresses may be nil ref: github.com/tailscale/tailscale/blob/8c5c87be2/wgengine/netstack/netstack.go#L768-L775 and: github.com/google/gvisor/blob/ffabadf0/pkg/tcpip/transport/tcp/endpoint.go#L2759

func (*GTCPConn) Read 

func (g *GTCPConn) Read(data []byte) (int, error)

func (*GTCPConn) RemoteAddr 

func (g *GTCPConn) RemoteAddr() net.Addr

func (*GTCPConn) SetDeadline 

func (g *GTCPConn) SetDeadline(t time.Time) error

func (*GTCPConn) SetReadDeadline 

func (g *GTCPConn) SetReadDeadline(t time.Time) error

func (*GTCPConn) SetWriteDeadline 

func (g *GTCPConn) SetWriteDeadline(t time.Time) error

func (*GTCPConn) Write 

func (g *GTCPConn) Write(data []byte) (int, error)

type GTCPConnHandler 

type GTCPConnHandler interface {
	GSpecConnHandler[*GTCPConn]
}

type GUDPConn 

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

func (*GUDPConn) Close 

func (g *GUDPConn) Close() error

Close closes the connection.

func (*GUDPConn) Establish 

func (g *GUDPConn) Establish() error

func (*GUDPConn) LocalAddr 

func (g *GUDPConn) LocalAddr() (addr net.Addr)

func (*GUDPConn) Read 

func (g *GUDPConn) Read(data []byte) (int, error)

func (*GUDPConn) ReadFrom 

func (g *GUDPConn) ReadFrom(data []byte) (int, net.Addr, error)

func (*GUDPConn) RemoteAddr 

func (g *GUDPConn) RemoteAddr() (addr net.Addr)

func (*GUDPConn) SetDeadline 

func (g *GUDPConn) SetDeadline(t time.Time) error

func (*GUDPConn) SetReadDeadline 

func (g *GUDPConn) SetReadDeadline(t time.Time) error

func (*GUDPConn) SetWriteDeadline 

func (g *GUDPConn) SetWriteDeadline(t time.Time) error

func (*GUDPConn) StatefulTeardown 

func (g *GUDPConn) StatefulTeardown() (fin bool)

func (*GUDPConn) Write 

func (g *GUDPConn) Write(data []byte) (int, error)

func (*GUDPConn) WriteTo 

func (g *GUDPConn) WriteTo(data []byte, addr net.Addr) (int, error)

type GUDPConnHandler 

type GUDPConnHandler interface {
	GSpecConnHandler[*GUDPConn]
	GMuxConnHandler[*GUDPConn]
}

type Options 

type Options struct {
	// FDs is a set of FDs used to read/write packets.
	FDs []int

	// MTU is the mtu to use for this endpoint.
	MTU uint32

	// EthernetHeader if true, indicates that the endpoint should read/write
	// ethernet frames instead of IP packets.
	EthernetHeader bool

	// Address is the link address for this endpoint. Only used if
	// EthernetHeader is true.
	Address tcpip.LinkAddress

	// SaveRestore if true, indicates that this NIC capability set should
	// include CapabilitySaveRestore
	SaveRestore bool

	// DisconnectOk if true, indicates that this NIC capability set should
	// include CapabilityDisconnectOk.
	DisconnectOk bool

	// TXChecksumOffload if true, indicates that this endpoints capability
	// set should include CapabilityTXChecksumOffload.
	TXChecksumOffload bool

	// RXChecksumOffload if true, indicates that this endpoints capability
	// set should include CapabilityRXChecksumOffload.
	RXChecksumOffload bool

	// If MaxSyscallHeaderBytes is non-zero, it is the maximum number of bytes
	// of struct iovec, msghdr, and mmsghdr that may be passed by each host
	// system call.
	MaxSyscallHeaderBytes int
}

Options specify the details about the fd-based endpoint to be created.

type PingAddr 

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

func PingAddrFromAddr 

func PingAddrFromAddr(addr netip.Addr) *PingAddr

func (PingAddr) Addr 

func (ipp PingAddr) Addr() netip.Addr

func (PingAddr) Network 

func (ipp PingAddr) Network() string

func (PingAddr) String 

func (ipp PingAddr) String() string

type SeamlessEndpoint 

type SeamlessEndpoint interface {
	stack.LinkEndpoint
	FdSwapper
}

func NewEndpoint 

func NewEndpoint(dev, mtu int, sink io.WriteCloser) (ep SeamlessEndpoint, err error)

ref: github.com/google/gvisor/blob/91f58d2cc/pkg/tcpip/sample/tun_tcp_echo/main.go#L102

func NewFdbasedInjectableEndpoint 

func NewFdbasedInjectableEndpoint(opts *Options) (SeamlessEndpoint, error)

New creates a new fd-based endpoint.

Makes fd non-blocking, but does not take ownership of fd, which must remain open for the lifetime of the returned endpoint (until after the endpoint has stopped being using and Wait returns).

type SnoopyEndpoint 

type SnoopyEndpoint struct {
	nested.Endpoint
	// contains filtered or unexported fields
}

SnoopyEndpoint is used to snoop and log network traffic.

func NewSnoopyEndpoint 

func NewSnoopyEndpoint(lower stack.LinkEndpoint, writer io.Writer) (*SnoopyEndpoint, error)

NewSnoopyEndpoint creates a new snoop link-layer endpoint. It wraps around another endpoint and logs packets as they traverse the endpoint.

Each packet is written to writer in the pcap format in a single Write call without synchronization. A snoop created with this function will not emit packets using the standard log package.

func (*SnoopyEndpoint) DeliverNetworkPacket 

func (e *SnoopyEndpoint) DeliverNetworkPacket(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer)

DeliverNetworkPacket implements the stack.NetworkDispatcher interface. It is called by the link-layer endpoint being wrapped when a packet arrives, and logs the packet before forwarding to the actual dispatcher.

func (*SnoopyEndpoint) DumpPacket 

func (e *SnoopyEndpoint) DumpPacket(dir Direction, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer, ts *time.Time)

DumpPacket logs a packet, depending on configuration, to stderr and/or a pcap file. ts is an optional timestamp for the packet.

func (*SnoopyEndpoint) WritePackets 

func (e *SnoopyEndpoint) WritePackets(pkts stack.PacketBufferList) (int, tcpip.Error)

WritePackets implements the stack.LinkEndpoint interface. It is called by higher-level protocols to write packets; it just logs the packet and forwards the request to the lower endpoint.

Source Files

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