V2 Netbird integration - UDP MIMO/SIMO, ICMPv6, DHCPv6 implementations (#106)

* begin adding udp.MuxHandler * add udp MuxHandlerSIMO/MIMO * add tcp rx shutdown * icmpv6 client * icmpv6 Client shared NDP/Echo preparation * icmpv6 client ndp/echo split * icmpv6 client ndp/echo split done * icmpv6 adjustments * add dhcpv6 stubs * dhcpv4 preliminary revision * add dns.NextLabel * dns label name tweaks * dns begin work on TCP client * add dnstcp package * apply gofmt changes * add udp mux tests * clean up, remove StackBig for now * remove dnstcp so as to merged confident parts and we continue dnstcp work elsewhere
2026-09-14 02:29:33 +00:00 · 2026-05-10 12:16:30 -03:00
parent bdbd38ab44
commit 7d5830d7ab
22 changed files with 2785 additions and 75 deletions
@@ -0,0 +1,223 @@
+package icmpv6
+
+import (
+	"encoding/binary"
+
+	"github.com/soypat/lneto"
+)
+
+//go:generate stringer -type=Type,CodeDestinationUnreachable,CodeParameterProblem -linecomment -output stringers.go
+
+const (
+	sizeHeader    = 8
+	sizeNDPBase   = sizeHeader + 16 // 24: ICMPv6 header + 16-byte target address
+	sizeNDPOption = 8               // 1 type + 1 len + 6 MAC (Ethernet link-layer option, RFC 4861 §4.6.1)
+	sizeNDP       = sizeNDPBase + sizeNDPOption
+)
+
+type Type uint8
+
+const (
+	TypeDestinationUnreachable Type = 1 // destination unreachable
+	TypePacketTooBig           Type = 2 // packet too big
+	TypeTimeExceeded           Type = 3 // time exceeded
+	TypeParameterProblem       Type = 4 // parameter problem
+
+	TypeEchoRequest Type = 128 // echo request
+	TypeEchoReply   Type = 129 // echo reply
+
+	TypeRouterSolicitation    Type = 133 // router solicitation
+	TypeRouterAdvertisement   Type = 134 // router advertisement
+	TypeNeighborSolicitation  Type = 135 // neighbor solicitation
+	TypeNeighborAdvertisement Type = 136 // neighbor advertisement
+	TypeRedirectMessage       Type = 137 // redirect message
+)
+
+type CodeTimeExceeded uint8
+
+const (
+	CodeHopLimitExceeded   CodeTimeExceeded = iota // hop limit exceeded in transit
+	CodeFragmentReassembly                         // fragment reassembly time exceeded
+)
+
+type CodeDestinationUnreachable uint8
+
+const (
+	CodeNoRoute             CodeDestinationUnreachable = iota // no route to destination
+	CodeAdminProhibited                                       // communication administratively prohibited
+	CodeBeyondScope                                           // beyond scope of source address
+	CodeAddressUnreachable                                    // address unreachable
+	CodePortUnreachable                                       // port unreachable
+	CodeIngressEgressPolicy                                   // source address failed ingress/egress policy
+	CodeRejectRoute                                           // reject route to destination
+)
+
+type CodeParameterProblem uint8
+
+const (
+	CodeErroneousHeaderField   CodeParameterProblem = iota // erroneous header field encountered
+	CodeUnrecognizedNextHeader                             // unrecognized next header type encountered
+	CodeUnrecognizedIPv6Option                             // unrecognized IPv6 option encountered
+)
+
+func NewFrame(buf []byte) (Frame, error) {
+	if len(buf) < sizeHeader {
+		return Frame{}, lneto.ErrTruncatedFrame
+	}
+	return Frame{buf: buf}, nil
+}
+
+type Frame struct {
+	buf []byte
+}
+
+func (frm Frame) Type() Type { return Type(frm.buf[0]) }
+
+func (frm Frame) SetType(t Type) { frm.buf[0] = uint8(t) }
+
+func (frm Frame) Code() uint8 { return frm.buf[1] }
+
+func (frm Frame) SetCode(code uint8) { frm.buf[1] = code }
+
+// CRC returns the checksum field of the frame.
+func (frm Frame) CRC() uint16 {
+	return binary.BigEndian.Uint16(frm.buf[2:4])
+}
+
+// SetCRC sets the checksum field of the frame.
+func (frm Frame) SetCRC(crc uint16) {
+	binary.BigEndian.PutUint16(frm.buf[2:4], crc)
+}
+
+func (frm Frame) payload() []byte {
+	return frm.buf[4:]
+}
+
+type FrameDestinationUnreachable struct {
+	Frame
+}
+
+func (frm FrameDestinationUnreachable) Code() CodeDestinationUnreachable {
+	return CodeDestinationUnreachable(frm.Frame.Code())
+}
+
+func (frm FrameDestinationUnreachable) SetCode(code CodeDestinationUnreachable) {
+	frm.Frame.SetCode(uint8(code))
+}
+
+type FramePacketTooBig struct {
+	Frame
+}
+
+func (frm FramePacketTooBig) MTU() uint32 {
+	return binary.BigEndian.Uint32(frm.buf[4:8])
+}
+
+func (frm FramePacketTooBig) SetMTU(mtu uint32) {
+	binary.BigEndian.PutUint32(frm.buf[4:8], mtu)
+}
+
+type FrameParameterProblem struct {
+	Frame
+}
+
+func (frm FrameParameterProblem) Code() CodeParameterProblem {
+	return CodeParameterProblem(frm.Frame.Code())
+}
+
+func (frm FrameParameterProblem) SetCode(code CodeParameterProblem) {
+	frm.Frame.SetCode(uint8(code))
+}
+
+// Pointer identifies the octet offset within the invoking packet where the error was detected.
+func (frm FrameParameterProblem) Pointer() uint32 {
+	return binary.BigEndian.Uint32(frm.buf[4:8])
+}
+
+func (frm FrameParameterProblem) SetPointer(ptr uint32) {
+	binary.BigEndian.PutUint32(frm.buf[4:8], ptr)
+}
+
+type FrameEcho struct {
+	Frame
+}
+
+func (frm FrameEcho) Identifier() uint16 {
+	return binary.BigEndian.Uint16(frm.buf[4:6])
+}
+
+func (frm FrameEcho) SetIdentifier(id uint16) {
+	binary.BigEndian.PutUint16(frm.buf[4:6], id)
+}
+
+func (frm FrameEcho) SequenceNumber() uint16 {
+	return binary.BigEndian.Uint16(frm.buf[6:8])
+}
+
+func (frm FrameEcho) SetSequenceNumber(seq uint16) {
+	binary.BigEndian.PutUint16(frm.buf[6:8], seq)
+}
+
+func (frm FrameEcho) Data() []byte {
+	return frm.buf[8:]
+}
+
+func (frm FrameEcho) RawData() []byte {
+	return frm.buf
+}
+
+// FrameNeighborSolicitation accesses a Neighbor Solicitation message (RFC 4861 §4.3).
+// Layout after ICMPv6 base header: Reserved(4B) | TargetAddr(16B) | Options.
+type FrameNeighborSolicitation struct {
+	Frame
+}
+
+// TargetAddr returns the IPv6 address being queried.
+func (frm FrameNeighborSolicitation) TargetAddr() *[16]byte {
+	return (*[16]byte)(frm.buf[8:24])
+}
+
+// Options returns the bytes following the fixed header for parsing NDP options.
+func (frm FrameNeighborSolicitation) Options() []byte {
+	return frm.buf[24:]
+}
+
+// FrameNeighborAdvertisement accesses a Neighbor Advertisement message (RFC 4861 §4.4).
+// Layout after ICMPv6 base header: R|S|O|Reserved(4B) | TargetAddr(16B) | Options.
+type FrameNeighborAdvertisement struct {
+	Frame
+}
+
+// Flags returns the R (router), S (solicited), O (override) flag bits.
+func (frm FrameNeighborAdvertisement) Flags() (router, solicited, override bool) {
+	b := frm.buf[4]
+	return b&0x80 != 0, b&0x40 != 0, b&0x20 != 0
+}
+
+// SetFlags sets the R, S, O flags and zeroes the reserved bits.
+func (frm FrameNeighborAdvertisement) SetFlags(router, solicited, override bool) {
+	var b byte
+	if router {
+		b |= 0x80
+	}
+	if solicited {
+		b |= 0x40
+	}
+	if override {
+		b |= 0x20
+	}
+	frm.buf[4] = b
+	frm.buf[5] = 0
+	frm.buf[6] = 0
+	frm.buf[7] = 0
+}
+
+// TargetAddr returns the IPv6 address being announced.
+func (frm FrameNeighborAdvertisement) TargetAddr() *[16]byte {
+	return (*[16]byte)(frm.buf[8:24])
+}
+
+// Options returns the bytes following the fixed header for parsing NDP options.
+func (frm FrameNeighborAdvertisement) Options() []byte {
+	return frm.buf[24:]
+}