Add flow dispatcher
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世界
parent
47bdde06c3
commit
ed63adda33
27 changed files with 2469 additions and 963 deletions
256
flow_parse.go
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256
flow_parse.go
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@ -0,0 +1,256 @@
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package tun
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import (
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"encoding/binary"
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"net/netip"
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"github.com/sagernet/sing-tun/gtcpip/header"
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)
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type flowKey struct {
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protocol uint8
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source netip.AddrPort
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destination netip.AddrPort
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}
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func (k flowKey) reversed() flowKey {
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return flowKey{protocol: k.protocol, source: k.destination, destination: k.source}
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}
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type forwardPacket struct {
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ipVersion uint8
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protocol uint8
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network header.Network
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transport []byte
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source netip.AddrPort
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destination netip.AddrPort
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tcpFlags header.TCPFlags
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icmpType uint8
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fragment bool
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hasFlow bool
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}
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func (p *forwardPacket) flowKey() flowKey {
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return flowKey{protocol: p.protocol, source: p.source, destination: p.destination}
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}
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func (p *forwardPacket) isTCPSyn() bool {
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return p.protocol == uint8(header.TCPProtocolNumber) && p.tcpFlags&header.TCPFlagSyn != 0
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}
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func parseForwardPacket(packet []byte) (forwardPacket, bool) {
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switch header.IPVersion(packet) {
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case header.IPv4Version:
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ipHdr := header.IPv4(packet)
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if !ipHdr.IsValid(len(packet)) {
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return forwardPacket{}, false
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}
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parsed := forwardPacket{
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ipVersion: 4,
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protocol: uint8(ipHdr.TransportProtocol()),
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network: ipHdr,
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source: netip.AddrPortFrom(ipHdr.SourceAddr(), 0),
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destination: netip.AddrPortFrom(ipHdr.DestinationAddr(), 0),
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}
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if ipHdr.More() || ipHdr.FragmentOffset() != 0 {
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parsed.fragment = true
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return parsed, true
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}
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parsed.parseTransport(ipHdr.Payload())
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return parsed, true
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case header.IPv6Version:
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ipHdr := header.IPv6(packet)
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if !ipHdr.IsValid(len(packet)) {
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return forwardPacket{}, false
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}
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protocol, payload, fragment, transportPresent := skipIPv6ExtensionHeaders(uint8(ipHdr.TransportProtocol()), ipHdr.Payload())
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parsed := forwardPacket{
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ipVersion: 6,
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protocol: protocol,
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network: ipHdr,
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source: netip.AddrPortFrom(ipHdr.SourceAddr(), 0),
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destination: netip.AddrPortFrom(ipHdr.DestinationAddr(), 0),
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fragment: fragment,
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}
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if fragment || !transportPresent {
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return parsed, true
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}
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parsed.parseTransport(payload)
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return parsed, true
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default:
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return forwardPacket{}, false
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}
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}
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func skipIPv6ExtensionHeaders(protocol uint8, payload []byte) (uint8, []byte, bool, bool) {
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for {
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switch header.IPv6ExtensionHeaderIdentifier(protocol) {
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case header.IPv6HopByHopOptionsExtHdrIdentifier, header.IPv6RoutingExtHdrIdentifier, header.IPv6DestinationOptionsExtHdrIdentifier:
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if len(payload) < 2 {
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return protocol, payload, false, false
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}
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extensionLength := (int(payload[1]) + 1) * 8
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if len(payload) < extensionLength {
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return protocol, payload, false, false
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}
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protocol = payload[0]
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payload = payload[extensionLength:]
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case header.IPv6FragmentExtHdrIdentifier:
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return protocol, payload, true, false
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default:
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return protocol, payload, false, true
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}
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}
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}
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func (p *forwardPacket) parseTransport(payload []byte) {
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p.transport = payload
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switch p.protocol {
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case uint8(header.TCPProtocolNumber):
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if len(payload) < header.TCPMinimumSize {
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return
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}
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tcpHdr := header.TCP(payload)
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p.source = netip.AddrPortFrom(p.source.Addr(), tcpHdr.SourcePort())
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p.destination = netip.AddrPortFrom(p.destination.Addr(), tcpHdr.DestinationPort())
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p.tcpFlags = tcpHdr.Flags()
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p.hasFlow = true
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case uint8(header.UDPProtocolNumber):
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if len(payload) < header.UDPMinimumSize {
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return
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}
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udpHdr := header.UDP(payload)
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p.source = netip.AddrPortFrom(p.source.Addr(), udpHdr.SourcePort())
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p.destination = netip.AddrPortFrom(p.destination.Addr(), udpHdr.DestinationPort())
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p.hasFlow = true
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case uint8(header.ICMPv4ProtocolNumber):
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if len(payload) < header.ICMPv4MinimumSize {
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return
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}
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icmpHdr := header.ICMPv4(payload)
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p.icmpType = uint8(icmpHdr.Type())
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switch icmpHdr.Type() {
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case header.ICMPv4Echo, header.ICMPv4EchoReply:
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identifier := icmpHdr.Ident()
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p.source = netip.AddrPortFrom(p.source.Addr(), identifier)
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p.destination = netip.AddrPortFrom(p.destination.Addr(), identifier)
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p.hasFlow = true
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}
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case uint8(header.ICMPv6ProtocolNumber):
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if len(payload) < header.ICMPv6MinimumSize {
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return
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}
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icmpHdr := header.ICMPv6(payload)
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p.icmpType = uint8(icmpHdr.Type())
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switch icmpHdr.Type() {
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case header.ICMPv6EchoRequest, header.ICMPv6EchoReply:
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identifier := icmpHdr.Ident()
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p.source = netip.AddrPortFrom(p.source.Addr(), identifier)
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p.destination = netip.AddrPortFrom(p.destination.Addr(), identifier)
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p.hasFlow = true
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}
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}
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}
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func (p *forwardPacket) isICMPError() bool {
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switch p.protocol {
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case uint8(header.ICMPv4ProtocolNumber):
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switch header.ICMPv4Type(p.icmpType) {
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case header.ICMPv4DstUnreachable, header.ICMPv4SrcQuench, header.ICMPv4Redirect, header.ICMPv4TimeExceeded, header.ICMPv4ParamProblem:
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return true
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}
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return false
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case uint8(header.ICMPv6ProtocolNumber):
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return header.ICMPv6Type(p.icmpType).IsErrorType()
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default:
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return false
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}
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}
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func (p *forwardPacket) icmpErrorInner() ([]byte, bool) {
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var innerOffset int
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switch p.protocol {
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case uint8(header.ICMPv4ProtocolNumber):
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innerOffset = header.ICMPv4MinimumSize
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case uint8(header.ICMPv6ProtocolNumber):
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innerOffset = header.ICMPv6ErrorHeaderSize
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default:
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return nil, false
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}
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if len(p.transport) <= innerOffset {
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return nil, false
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}
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return p.transport[innerOffset:], true
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}
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type embeddedPacket struct {
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network header.Network
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payload []byte
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protocol uint8
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source netip.AddrPort
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destination netip.AddrPort
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}
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func (p *embeddedPacket) flowKey() flowKey {
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return flowKey{protocol: p.protocol, source: p.source, destination: p.destination}
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}
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func parseEmbedded(inner []byte) (embeddedPacket, bool) {
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switch header.IPVersion(inner) {
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case header.IPv4Version:
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if len(inner) < header.IPv4MinimumSize {
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return embeddedPacket{}, false
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}
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ipHdr := header.IPv4(inner)
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headerLength := int(ipHdr.HeaderLength())
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if headerLength < header.IPv4MinimumSize || headerLength > len(inner) {
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return embeddedPacket{}, false
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}
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return parseEmbeddedTransport(ipHdr, inner[headerLength:], uint8(ipHdr.TransportProtocol()), ipHdr.SourceAddr(), ipHdr.DestinationAddr())
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case header.IPv6Version:
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if len(inner) < header.IPv6MinimumSize {
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return embeddedPacket{}, false
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}
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ipHdr := header.IPv6(inner)
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protocol, payload, _, transportPresent := skipIPv6ExtensionHeaders(uint8(ipHdr.TransportProtocol()), inner[header.IPv6MinimumSize:])
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if !transportPresent {
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return embeddedPacket{}, false
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}
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return parseEmbeddedTransport(ipHdr, payload, protocol, ipHdr.SourceAddr(), ipHdr.DestinationAddr())
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default:
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return embeddedPacket{}, false
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}
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}
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func parseEmbeddedTransport(network header.Network, payload []byte, protocol uint8, source, destination netip.Addr) (embeddedPacket, bool) {
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embedded := embeddedPacket{
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network: network,
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payload: payload,
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protocol: protocol,
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}
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switch protocol {
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case uint8(header.TCPProtocolNumber), uint8(header.UDPProtocolNumber):
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if len(payload) < 4 {
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return embeddedPacket{}, false
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}
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embedded.source = netip.AddrPortFrom(source, binary.BigEndian.Uint16(payload[0:]))
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embedded.destination = netip.AddrPortFrom(destination, binary.BigEndian.Uint16(payload[2:]))
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case uint8(header.ICMPv4ProtocolNumber):
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if len(payload) < header.ICMPv4MinimumSize {
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return embeddedPacket{}, false
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}
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identifier := header.ICMPv4(payload).Ident()
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embedded.source = netip.AddrPortFrom(source, identifier)
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embedded.destination = netip.AddrPortFrom(destination, identifier)
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case uint8(header.ICMPv6ProtocolNumber):
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if len(payload) < header.ICMPv6MinimumSize {
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return embeddedPacket{}, false
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}
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identifier := header.ICMPv6(payload).Ident()
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embedded.source = netip.AddrPortFrom(source, identifier)
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embedded.destination = netip.AddrPortFrom(destination, identifier)
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default:
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return embeddedPacket{}, false
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}
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return embedded, true
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}
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