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52 lines
1.2 KiB
Go
52 lines
1.2 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package packet
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import "encoding/binary"
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// UDP6Header is an IPv6+UDP header.
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type UDP6Header struct {
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IP6Header
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SrcPort uint16
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DstPort uint16
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}
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// Len implements Header.
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func (h UDP6Header) Len() int {
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return h.IP6Header.Len() + udpHeaderLength
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}
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// Marshal implements Header.
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func (h UDP6Header) Marshal(buf []byte) error {
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if len(buf) < h.Len() {
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return errSmallBuffer
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}
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if len(buf) > maxPacketLength {
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return errLargePacket
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}
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// The caller does not need to set this.
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h.IPProto = UDP
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length := len(buf) - h.IP6Header.Len()
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binary.BigEndian.PutUint16(buf[40:42], h.SrcPort)
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binary.BigEndian.PutUint16(buf[42:44], h.DstPort)
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binary.BigEndian.PutUint16(buf[44:46], uint16(length))
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binary.BigEndian.PutUint16(buf[46:48], 0) // blank checksum
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// UDP checksum with IP pseudo header.
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h.IP6Header.marshalPseudo(buf)
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binary.BigEndian.PutUint16(buf[46:48], ip4Checksum(buf[:]))
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h.IP6Header.Marshal(buf)
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return nil
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}
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// ToResponse implements Header.
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func (h *UDP6Header) ToResponse() {
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h.SrcPort, h.DstPort = h.DstPort, h.SrcPort
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h.IP6Header.ToResponse()
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}
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