Update dependencies

vendor/tailscale.com/net/packet/ip6.go

@@ -0,0 +1,76 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package packet
+
+import (
+	"encoding/binary"
+	"net/netip"
+
+	"tailscale.com/types/ipproto"
+)
+
+// ip6HeaderLength is the length of an IPv6 header with no IP options.
+const ip6HeaderLength = 40
+
+// IP6Header represents an IPv6 packet header.
+type IP6Header struct {
+	IPProto ipproto.Proto
+	IPID    uint32 // only lower 20 bits used
+	Src     netip.Addr
+	Dst     netip.Addr
+}
+
+// Len implements Header.
+func (h IP6Header) Len() int {
+	return ip6HeaderLength
+}
+
+// Marshal implements Header.
+func (h IP6Header) Marshal(buf []byte) error {
+	if len(buf) < h.Len() {
+		return errSmallBuffer
+	}
+	if len(buf) > maxPacketLength {
+		return errLargePacket
+	}
+
+	binary.BigEndian.PutUint32(buf[:4], h.IPID&0x000FFFFF)
+	buf[0] = 0x60
+	binary.BigEndian.PutUint16(buf[4:6], uint16(len(buf)-ip6HeaderLength)) // Total length
+	buf[6] = uint8(h.IPProto)                                              // Inner protocol
+	buf[7] = 64                                                            // TTL
+	src, dst := h.Src.As16(), h.Dst.As16()
+	copy(buf[8:24], src[:])
+	copy(buf[24:40], dst[:])
+
+	return nil
+}
+
+// ToResponse implements Header.
+func (h *IP6Header) ToResponse() {
+	h.Src, h.Dst = h.Dst, h.Src
+	// Flip the bits in the IPID. If incoming IPIDs are distinct, so are these.
+	h.IPID = (^h.IPID) & 0x000FFFFF
+}
+
+// marshalPseudo serializes h into buf in the "pseudo-header" form
+// required when calculating UDP checksums.
+func (h IP6Header) marshalPseudo(buf []byte, proto ipproto.Proto) error {
+	if len(buf) < h.Len() {
+		return errSmallBuffer
+	}
+	if len(buf) > maxPacketLength {
+		return errLargePacket
+	}
+
+	src, dst := h.Src.As16(), h.Dst.As16()
+	copy(buf[:16], src[:])
+	copy(buf[16:32], dst[:])
+	binary.BigEndian.PutUint32(buf[32:36], uint32(len(buf)-h.Len()))
+	buf[36] = 0
+	buf[37] = 0
+	buf[38] = 0
+	buf[39] = byte(proto) // NextProto
+	return nil
+}