ODPM 266: Go-libmemif + 2 examples.

Change-Id: Icdb9b9eb2314eff6c96afe7996fcf2728291de4a
Signed-off-by: Milan Lenco <milan.lenco@pantheon.tech>

1 files changed, 416 insertions, 0 deletions

diff --git a/vendor/github.com/google/gopacket/layers/ntp.go b/vendor/github.com/google/gopacket/layers/ntp.go
new file mode 100644
index 0000000..33c15b3
--- /dev/null
+++ b/vendor/github.com/google/gopacket/layers/ntp.go
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+// Copyright 2016 Google, Inc. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree.
+//
+//******************************************************************************
+
+package layers
+
+import (
+	"encoding/binary"
+	"errors"
+
+	"github.com/google/gopacket"
+)
+
+//******************************************************************************
+//
+// Network Time Protocol (NTP) Decoding Layer
+// ------------------------------------------
+// This file provides a GoPacket decoding layer for NTP.
+//
+//******************************************************************************
+//
+// About The Network Time Protocol (NTP)
+// -------------------------------------
+// NTP is a protocol that enables computers on the internet to set their
+// clocks to the correct time (or to a time that is acceptably close to the
+// correct time). NTP runs on top of UDP.
+//
+// There have been a series of versions of the NTP protocol. The latest
+// version is V4 and is specified in RFC 5905:
+//     http://www.ietf.org/rfc/rfc5905.txt
+//
+//******************************************************************************
+//
+// References
+// ----------
+//
+// Wikipedia's NTP entry:
+//     https://en.wikipedia.org/wiki/Network_Time_Protocol
+//     This is the best place to get an overview of NTP.
+//
+// Network Time Protocol Home Website:
+//     http://www.ntp.org/
+//     This appears to be the official website of NTP.
+//
+// List of current NTP Protocol RFCs:
+//     http://www.ntp.org/rfc.html
+//
+// RFC 958: "Network Time Protocol (NTP)" (1985)
+//     https://tools.ietf.org/html/rfc958
+//     This is the original NTP specification.
+//
+// RFC 1305: "Network Time Protocol (Version 3) Specification, Implementation and Analysis" (1992)
+//     https://tools.ietf.org/html/rfc1305
+//     The protocol was updated in 1992 yielding NTP V3.
+//
+// RFC 5905: "Network Time Protocol Version 4: Protocol and Algorithms Specification" (2010)
+//     https://www.ietf.org/rfc/rfc5905.txt
+//     The protocol was updated in 2010 yielding NTP V4.
+//     V4 is backwards compatible with all previous versions of NTP.
+//
+// RFC 5906: "Network Time Protocol Version 4: Autokey Specification"
+//     https://tools.ietf.org/html/rfc5906
+//     This document addresses the security of the NTP protocol
+//     and is probably not relevant to this package.
+//
+// RFC 5907: "Definitions of Managed Objects for Network Time Protocol Version 4 (NTPv4)"
+//     https://tools.ietf.org/html/rfc5907
+//     This document addresses the management of NTP servers and
+//     is probably not relevant to this package.
+//
+// RFC 5908: "Network Time Protocol (NTP) Server Option for DHCPv6"
+//     https://tools.ietf.org/html/rfc5908
+//     This document addresses the use of NTP in DHCPv6 and is
+//     probably not relevant to this package.
+//
+// "Let's make a NTP Client in C"
+//     https://lettier.github.io/posts/2016-04-26-lets-make-a-ntp-client-in-c.html
+//     This web page contains useful information about the details of NTP,
+//     including an NTP record struture in C, and C code.
+//
+// "NTP Packet Header (NTP Reference Implementation) (Computer Network Time Synchronization)"
+//     http://what-when-how.com/computer-network-time-synchronization/
+//        ntp-packet-header-ntp-reference-implementation-computer-network-time-synchronization/
+//     This web page contains useful information on the details of NTP.
+//
+// "Technical information - NTP Data Packet"
+//     https://www.meinbergglobal.com/english/info/ntp-packet.htm
+//     This page has a helpful diagram of an NTP V4 packet.
+//
+//******************************************************************************
+//
+// Obsolete References
+// -------------------
+//
+// RFC 1119: "RFC-1119 "Network Time Protocol (Version 2) Specification and Implementation" (1989)
+//     https://tools.ietf.org/html/rfc1119
+//     Version 2 was drafted in 1989.
+//     It is unclear whether V2 was ever implememented or whether the
+//     ideas ended up in V3 (which was implemented in 1992).
+//
+// RFC 1361: "Simple Network Time Protocol (SNTP)"
+//     https://tools.ietf.org/html/rfc1361
+//     This document is obsoleted by RFC 1769 and is included only for completeness.
+//
+// RFC 1769: "Simple Network Time Protocol (SNTP)"
+//     https://tools.ietf.org/html/rfc1769
+//     This document is obsoleted by RFC 2030 and RFC 4330 and is included only for completeness.
+//
+// RFC 2030: "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI"
+//     https://tools.ietf.org/html/rfc2030
+//     This document is obsoleted by RFC 4330 and is included only for completeness.
+//
+// RFC 4330: "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI"
+//     https://tools.ietf.org/html/rfc4330
+//     This document is obsoleted by RFC 5905 and is included only for completeness.
+//
+//******************************************************************************
+//
+// Endian And Bit Numbering Issues
+// -------------------------------
+//
+// Endian and bit numbering issues can be confusing. Here is some
+// clarification:
+//
+//    ENDIAN: Values are sent big endian.
+//    https://en.wikipedia.org/wiki/Endianness
+//
+//    BIT NUMBERING: Bits are numbered 0 upwards from the most significant
+//    bit to the least significant bit. This means that if there is a 32-bit
+//    value, the most significant bit is called bit 0 and the least
+//    significant bit is called bit 31.
+//
+// See RFC 791 Appendix B for more discussion.
+//
+//******************************************************************************
+//
+// NTP V3 and V4 Packet Format
+// ---------------------------
+// NTP packets are UDP packets whose payload contains an NTP record.
+//
+// The NTP RFC defines the format of the NTP record.
+//
+// There have been four versions of the protocol:
+//
+//    V1 in 1985
+//    V2 in 1989
+//    V3 in 1992
+//    V4 in 2010
+//
+// It is clear that V1 and V2 are obsolete, and there is no need to
+// cater for these formats.
+//
+// V3 and V4 essentially use the same format, with V4 adding some optional
+// fields on the end. So this package supports the V3 and V4 formats.
+//
+// The current version of NTP (NTP V4)'s RFC (V4 - RFC 5905) contains
+// the following diagram for the NTP record format:
+
+//      0                   1                   2                   3
+//      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |LI | VN  |Mode |    Stratum    |     Poll      |   Precision   |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                         Root Delay                            |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                         Root Dispersion                       |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                          Reference ID                         |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     +                     Reference Timestamp (64)                  +
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     +                      Origin Timestamp (64)                    +
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     +                      Receive Timestamp (64)                   +
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     +                      Transmit Timestamp (64)                  +
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     .                                                               .
+//     .                    Extension Field 1 (variable)               .
+//     .                                                               .
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     .                                                               .
+//     .                    Extension Field 2 (variable)               .
+//     .                                                               .
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                          Key Identifier                       |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     |                                                               |
+//     |                            dgst (128)                         |
+//     |                                                               |
+//     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//     From http://www.ietf.org/rfc/rfc5905.txt
+//
+// The fields "Extension Field 1 (variable)" and later are optional fields,
+// and so we can set a minimum NTP record size of 48 bytes.
+//
+const ntpMinimumRecordSizeInBytes int = 48
+
+//******************************************************************************
+
+// NTP Type
+// --------
+// Type NTP implements the DecodingLayer interface. Each NTP object
+// represents in a structured form the NTP record present as the UDP
+// payload in an NTP UDP packet.
+//
+
+type NTPLeapIndicator uint8
+type NTPVersion uint8
+type NTPMode uint8
+type NTPStratum uint8
+type NTPLog2Seconds int8
+type NTPFixed16Seconds uint32
+type NTPReferenceID uint32
+type NTPTimestamp uint64
+
+type NTP struct {
+	BaseLayer // Stores the packet bytes and payload bytes.
+
+	LeapIndicator      NTPLeapIndicator  // [0,3]. Indicates whether leap second(s) is to be added.
+	Version            NTPVersion        // [0,7]. Version of the NTP protocol.
+	Mode               NTPMode           // [0,7]. Mode.
+	Stratum            NTPStratum        // [0,255]. Stratum of time server in the server tree.
+	Poll               NTPLog2Seconds    // [-128,127]. The maximum interval between successive messages, in log2 seconds.
+	Precision          NTPLog2Seconds    // [-128,127]. The precision of the system clock, in log2 seconds.
+	RootDelay          NTPFixed16Seconds // [0,2^32-1]. Total round trip delay to the reference clock in seconds times 2^16.
+	RootDispersion     NTPFixed16Seconds // [0,2^32-1]. Total dispersion to the reference clock, in seconds times 2^16.
+	ReferenceID        NTPReferenceID    // ID code of reference clock [0,2^32-1].
+	ReferenceTimestamp NTPTimestamp      // Most recent timestamp from the reference clock.
+	OriginTimestamp    NTPTimestamp      // Local time when request was sent from local host.
+	ReceiveTimestamp   NTPTimestamp      // Local time (on server) that request arrived at server host.
+	TransmitTimestamp  NTPTimestamp      // Local time (on server) that request departed server host.
+
+	// FIX: This package should analyse the extension fields and represent the extension fields too.
+	ExtensionBytes []byte // Just put extensions in a byte slice.
+}
+
+//******************************************************************************
+
+// LayerType returns the layer type of the NTP object, which is LayerTypeNTP.
+func (d *NTP) LayerType() gopacket.LayerType {
+	return LayerTypeNTP
+}
+
+//******************************************************************************
+
+// decodeNTP analyses a byte slice and attempts to decode it as an NTP
+// record of a UDP packet.
+//
+// If it succeeds, it loads p with information about the packet and returns nil.
+// If it fails, it returns an error (non nil).
+//
+// This function is employed in layertypes.go to register the NTP layer.
+func decodeNTP(data []byte, p gopacket.PacketBuilder) error {
+
+	// Attempt to decode the byte slice.
+	d := &NTP{}
+	err := d.DecodeFromBytes(data, p)
+	if err != nil {
+		return err
+	}
+
+	// If the decoding worked, add the layer to the packet and set it
+	// as the application layer too, if there isn't already one.
+	p.AddLayer(d)
+	p.SetApplicationLayer(d)
+
+	return nil
+}
+
+//******************************************************************************
+
+// DecodeFromBytes analyses a byte slice and attempts to decode it as an NTP
+// record of a UDP packet.
+//
+// Upon succeeds, it loads the NTP object with information about the packet
+// and returns nil.
+// Upon failure, it returns an error (non nil).
+func (d *NTP) DecodeFromBytes(data []byte, df gopacket.DecodeFeedback) error {
+
+	// If the data block is too short to be a NTP record, then return an error.
+	if len(data) < ntpMinimumRecordSizeInBytes {
+		df.SetTruncated()
+		return errors.New("NTP packet too short")
+	}
+
+	// RFC 5905 does not appear to define a maximum NTP record length.
+	// The protocol allows "extension fields" to be included in the record,
+	// and states about these fields:"
+	//
+	//     "While the minimum field length containing required fields is
+	//      four words (16 octets), a maximum field length remains to be
+	//      established."
+	//
+	// For this reason, the packet length is not checked here for being too long.
+
+	// NTP type embeds type BaseLayer which contains two fields:
+	//    Contents is supposed to contain the bytes of the data at this level.
+	//    Payload is supposed to contain the payload of this level.
+	// Here we set the baselayer to be the bytes of the NTP record.
+	d.BaseLayer = BaseLayer{Contents: data[:len(data)]}
+
+	// Extract the fields from the block of bytes.
+	// To make sense of this, refer to the packet diagram
+	// above and the section on endian conventions.
+
+	// The first few fields are all packed into the first 32 bits. Unpack them.
+	f := data[0]
+	d.LeapIndicator = NTPLeapIndicator((f & 0xC0) >> 6)
+	d.Version = NTPVersion((f & 0x38) >> 3)
+	d.Mode = NTPMode(f & 0x07)
+	d.Stratum = NTPStratum(data[1])
+	d.Poll = NTPLog2Seconds(data[2])
+	d.Precision = NTPLog2Seconds(data[3])
+
+	// The remaining fields can just be copied in big endian order.
+	d.RootDelay = NTPFixed16Seconds(binary.BigEndian.Uint32(data[4:8]))
+	d.RootDispersion = NTPFixed16Seconds(binary.BigEndian.Uint32(data[8:12]))
+	d.ReferenceID = NTPReferenceID(binary.BigEndian.Uint32(data[12:16]))
+	d.ReferenceTimestamp = NTPTimestamp(binary.BigEndian.Uint64(data[16:24]))
+	d.OriginTimestamp = NTPTimestamp(binary.BigEndian.Uint64(data[24:32]))
+	d.ReceiveTimestamp = NTPTimestamp(binary.BigEndian.Uint64(data[32:40]))
+	d.TransmitTimestamp = NTPTimestamp(binary.BigEndian.Uint64(data[40:48]))
+
+	// This layer does not attempt to analyse the extension bytes.
+	// But if there are any, we'd like the user to know. So we just
+	// place them all in an ExtensionBytes field.
+	d.ExtensionBytes = data[48:]
+
+	// Return no error.
+	return nil
+}
+
+// SerializeTo writes the serialized form of this layer into the
+// SerializationBuffer, implementing gopacket.SerializableLayer.
+// See the docs for gopacket.SerializableLayer for more info.
+func (d *NTP) SerializeTo(b gopacket.SerializeBuffer, opts gopacket.SerializeOptions) error {
+	data, err := b.PrependBytes(ntpMinimumRecordSizeInBytes)
+	if err != nil {
+		return err
+	}
+
+	// Pack the first few fields into the first 32 bits.
+	h := uint8(0)
+	h |= (uint8(d.LeapIndicator) << 6) & 0xC0
+	h |= (uint8(d.Version) << 3) & 0x38
+	h |= (uint8(d.Mode)) & 0x07
+	data[0] = byte(h)
+	data[1] = byte(d.Stratum)
+	data[2] = byte(d.Poll)
+	data[3] = byte(d.Precision)
+
+	// The remaining fields can just be copied in big endian order.
+	binary.BigEndian.PutUint32(data[4:8], uint32(d.RootDelay))
+	binary.BigEndian.PutUint32(data[8:12], uint32(d.RootDispersion))
+	binary.BigEndian.PutUint32(data[12:16], uint32(d.ReferenceID))
+	binary.BigEndian.PutUint64(data[16:24], uint64(d.ReferenceTimestamp))
+	binary.BigEndian.PutUint64(data[24:32], uint64(d.OriginTimestamp))
+	binary.BigEndian.PutUint64(data[32:40], uint64(d.ReceiveTimestamp))
+	binary.BigEndian.PutUint64(data[40:48], uint64(d.TransmitTimestamp))
+
+	ex, err := b.AppendBytes(len(d.ExtensionBytes))
+	if err != nil {
+		return err
+	}
+	copy(ex, d.ExtensionBytes)
+
+	return nil
+}
+
+//******************************************************************************
+
+// CanDecode returns a set of layers that NTP objects can decode.
+// As NTP objects can only decide the NTP layer, we can return just that layer.
+// Apparently a single layer type implements LayerClass.
+func (d *NTP) CanDecode() gopacket.LayerClass {
+	return LayerTypeNTP
+}
+
+//******************************************************************************
+
+// NextLayerType specifies the next layer that GoPacket should attempt to
+// analyse after this (NTP) layer. As NTP packets do not contain any payload
+// bytes, there are no further layers to analyse.
+func (d *NTP) NextLayerType() gopacket.LayerType {
+	return gopacket.LayerTypeZero
+}
+
+//******************************************************************************
+
+// NTP packets do not carry any data payload, so the empty byte slice is retured.
+// In Go, a nil slice is functionally identical to an empty slice, so we
+// return nil to avoid a heap allocation.
+func (d *NTP) Payload() []byte {
+	return nil
+}
+
+//******************************************************************************
+//*                            End Of NTP File                                 *
+//******************************************************************************