ndn

package module
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 Go to latest Published: Dec 10, 2020 License: MIT, NIST-PD-fallback Imports: 16 Imported by: 0

README

Go-NDN: Named Data Networking Forwarder Library for Go

Go-NDN is a fork of the NDNgo library specialized for use with the YaNFD forwarder. This was done to implement missing features that are needed for this forwarder and reduce the size of the dependency.

Features

Packet Encoding and Decoding
  • General purpose TLV codec (in package tlv)
  • Interests and Data packets: v0.3 format only
    • TLV evolvability: yes
    • Signed Interest: basic support (expansion planned)
  • NDNLPv2
    • Fragmentation and reassembly: planned
    • Nacks: no
    • PIT tokens: yes
    • Congestion marks: yes
    • Link layer reliability: planned
    • Self-learning: planned
  • Naming Convention: no
Key Chain

Documentation

Overview

Package ndn implements Named Data Networking (NDN) packet semantics. This is the top-level package of NDNgo, a minimal NDN library in pure Go.

This package contains the following important types: 

Packet representation:
- Interest
- Data
- Packet

Link protocol:
- LpPacket

Security abstraction:
- Signer
- Verifier

Index

Constants

View Source 
const (
	DefaultInterestLifetime time.Duration = 4000 * time.Millisecond
	MinInterestLifetime     time.Duration = 1 * time.Millisecond

	MinHopLimit = 1
	MaxHopLimit = math.MaxUint8
)

Defaults and limits.

View Source 
const (
	// CanBePrefixFlag enables CanBePrefix in NewInterest.
	CanBePrefixFlag = tCanBePrefix(true)

	// MustBeFreshFlag enables MustBeFresh in NewInterest.
	MustBeFreshFlag = tMustBeFresh(true)
)

Variables

View Source 
var (
	ErrNotLpFrame     = errors.New("not NDNLPv2 frame")
	ErrUnexpectedElem = errors.New("unexpected TLV element")
	ErrFragment       = errors.New("bad fragment")
	ErrReliability    = errors.New("error encoding reliability headers")
	ErrSequenceSize   = errors.New("sequence number not 8 octets")
	ErrL3Type         = errors.New("unknown L3 packet type")
	ErrComponentType  = errors.New("NameComponent TLV-TYPE out of range")
	ErrNonceLen       = errors.New("Nonce wrong length")
	ErrLifetime       = errors.New("InterestLifetime out of range")
	ErrHopLimit       = errors.New("HopLimit out of range")
	ErrParamsDigest   = errors.New("bad ParamsDigest")
	ErrSigType        = errors.New("bad SigType")
	ErrKeyLocator     = errors.New("bad KeyLocator")
	ErrSigNonce       = errors.New("bad SigNonce")
	ErrSigValue       = errors.New("bad SigValue")
)

Simple error conditions.

Functions

func PitTokenFromUint 

func PitTokenFromUint(n uint64) []byte

PitTokenFromUint creates a PIT token from uint64, interpreted as big endian.

func PitTokenToUint 

func PitTokenToUint(token []byte) uint64

PitTokenToUint reads a 8-octet PIT token as uint64, interpreted as big endian. Returns 0 if the input token is not 8 octets.

func RegisterSigInfoExtension 

func RegisterSigInfoExtension(typ uint32)

RegisterSigInfoExtension registers an extension TLV-TYPE in SigInfo.

Types

type ContentType 

type ContentType uint

ContentType represents a ContentType field.

func (ContentType) MarshalTlv 

func (ct ContentType) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this ContentType.

func (*ContentType) UnmarshalBinary 

func (ct *ContentType) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from wire encoding.

type Data 

type Data struct {
	Name        Name
	ContentType ContentType
	Freshness   time.Duration
	Content     []byte
	SigInfo     *SigInfo
	SigValue    []byte
	// contains filtered or unexported fields
}

Data represents a Data packet.

func MakeData 

func MakeData(args ...interface{}) (data Data)

MakeData creates a Data from flexible arguments. Arguments can contain:

  • string or Name: set Name
  • ContentType
  • time.Duration: set Freshness
  • []byte: set Content
  • LpL3: copy PitToken and CongMark
  • Interest or *Interest: copy Name, set FreshnessPeriod if Interest has MustBeFresh, inherit LpL3

func (Data) CanSatisfy 

func (data Data) CanSatisfy(interest Interest) bool

CanSatisfy determines whether this Data can satisfy the given Interest.

func (Data) ComputeDigest 

func (data Data) ComputeDigest() []byte

ComputeDigest computes implicit digest of this Data.

If data was decoded from Packet (data.packet is assigned), the digest is of the origin packet. Computed digest is cached on data.packet. Modifying a decoded Data will cause this function to return incorrect digest.

If data was constructed (data.packet is unassigned), the digest is of the encoding of the current packet, and is not cached.

func (Data) FullName 

func (data Data) FullName() Name

FullName returns full name of this Data.

func (Data) MarshalTlv 

func (data Data) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this Data.

func (*Data) SignWith 

func (data *Data) SignWith(signer func(name Name, si *SigInfo) (LLSign, error)) error

SignWith implements Signable interface. Caller should use signer.Sign(data).

func (Data) String 

func (data Data) String() string

func (Data) ToPacket 

func (data Data) ToPacket() *Packet

ToPacket wraps Data as Packet.

func (*Data) UnmarshalBinary 

func (data *Data) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

func (Data) VerifyWith 

func (data Data) VerifyWith(verifier func(name Name, si SigInfo) (LLVerify, error)) error

VerifyWith implements Verifiable interface. Caller should use verifier.Verify(data).

If data was decoded from Packet (data.packet is assigned), verification is on the origin packet. Modifying a decoded Data will cause this function to return incorrect result.

If data was constructed (data.packet is unassigned), verification is on the encoding of the current packet.

type FHDelegation 

type FHDelegation struct {
	Preference int
	Name       Name
}

FHDelegation represents a delegation of forwarding hint.

func MakeFHDelegation 

func MakeFHDelegation(preference int, name interface{}) (del FHDelegation)

MakeFHDelegation creates a delegation. name should be either Name or string.

func (FHDelegation) MarshalTlv 

func (del FHDelegation) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this delegation.

func (*FHDelegation) UnmarshalBinary 

func (del *FHDelegation) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

type ForwardingHint 

type ForwardingHint []FHDelegation

ForwardingHint represents a forwarding hint.

func (*ForwardingHint) Append 

func (fh *ForwardingHint) Append(preference int, name interface{})

Append adds a delegation. name should be either Name or string.

func (ForwardingHint) MarshalTlv 

func (fh ForwardingHint) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this forwarding hint.

func (*ForwardingHint) UnmarshalBinary 

func (fh *ForwardingHint) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

type HopLimit 

type HopLimit uint8

HopLimit represents a HopLimit field.

func (HopLimit) MarshalTlv 

func (hl HopLimit) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this HopLimit.

func (*HopLimit) UnmarshalBinary 

func (hl *HopLimit) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from wire encoding.

type Interest 

type Interest struct {
	Name           Name
	CanBePrefix    bool
	MustBeFresh    bool
	ForwardingHint ForwardingHint
	Nonce          Nonce
	Lifetime       time.Duration
	HopLimit       HopLimit
	AppParameters  []byte
	SigInfo        *SigInfo
	SigValue       []byte
	// contains filtered or unexported fields
}

Interest represents an Interest packet.

func MakeInterest 

func MakeInterest(args ...interface{}) (interest Interest)

MakeInterest creates an Interest from flexible arguments. Arguments can contain:

  • string or Name: set Name
  • CanBePrefixFlag: set CanBePrefix
  • MustBeFreshFlag: set MustBeFresh
  • FHDelegation: append forwarding hint delegation
  • Nonce: set Nonce
  • time.Duration: set Lifetime
  • HopLimit: set HopLimit
  • []byte: set AppParameters
  • LpL3: copy PitToken and CongMark

func (*Interest) ApplyDefaultLifetime 

func (interest *Interest) ApplyDefaultLifetime() time.Duration

ApplyDefaultLifetime updates Lifetime to the default if it is not set.

func (Interest) MarshalTlv 

func (interest Interest) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this Interest.

func (*Interest) SignWith 

func (interest *Interest) SignWith(signer func(name Name, si *SigInfo) (LLSign, error)) error

SignWith implements Signable interface. Caller should use signer.Sign(interest).

func (Interest) String 

func (interest Interest) String() string

func (Interest) ToPacket 

func (interest Interest) ToPacket() *Packet

ToPacket wraps Interest as Packet.

func (*Interest) UnmarshalBinary 

func (interest *Interest) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

func (*Interest) UpdateParamsDigest 

func (interest *Interest) UpdateParamsDigest()

UpdateParamsDigest appends or updates ParametersSha256DigestComponent. It will not remove erroneously present or duplicate ParametersSha256DigestComponent.

func (Interest) VerifyWith 

func (interest Interest) VerifyWith(verifier func(name Name, si SigInfo) (LLVerify, error)) error

VerifyWith implements Verifiable interface. Caller should use verifier.Verify(interest).

This function cannot verify an Interest that contains unrecognized TLV elements.

type KeyLocator 

type KeyLocator struct {
	Name   Name
	Digest []byte
}

KeyLocator represents KeyLocator in SignatureInfo.

func (KeyLocator) Empty 

func (kl KeyLocator) Empty() bool

Empty returns true if KeyLocator has zero fields.

func (KeyLocator) MarshalTlv 

func (kl KeyLocator) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this KeyLocator.

func (KeyLocator) String 

func (kl KeyLocator) String() string

func (*KeyLocator) UnmarshalBinary 

func (kl *KeyLocator) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

type L3Packet 

type L3Packet interface {
	ToPacket() *Packet
}

L3Packet represents any NDN layer 3 packet.

type LLSign 

type LLSign func(input []byte) (sig []byte, e error)

LLSign is a low-level signing function.

type LLVerify 

type LLVerify func(input, sig []byte) error

LLVerify is a low-level verification function.

type LpL3 

type LpL3 struct {
	PitToken        []byte
	NextHopFaceID   uint64
	IncomingFaceID  uint64
	CachePolicyType uint64 // CachePolicy wrapper is implicit
	CongestionMark  uint64
}

LpL3 contains layer 3 fields in NDNLPv2 header.

func (LpL3) Empty 

func (lph LpL3) Empty() bool

Empty returns true if LpL3 has zero fields.

type LpPacket 

type LpPacket struct {
	Sequence            util.Optional
	FragIndex           int
	FragCount           int
	Acks                []uint64
	TxSequence          util.Optional
	SelfLearningHeaders SelfLearningHeaders
	LpFragment          *Packet
}

LpPacket represents an NDNLPv2 frame.

func MakeLpPacket 

func MakeLpPacket() LpPacket

MakeLpPacket constructs an empty LpPacket.

func (LpPacket) MarshalTlv 

func (lp LpPacket) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this frame.

func (LpPacket) String 

func (lp LpPacket) String() string

func (*LpPacket) UnmarshalTlv 

func (lp *LpPacket) UnmarshalTlv(typ uint32, value []byte) error

UnmarshalTlv decodes from wire format.

type Name 

type Name []NameComponent

Name represents a name. The zero Name has zero components.

func ParseName 

func ParseName(input string) (name Name)

ParseName parses URI representation of name. It uses best effort and can accept any input.

func (Name) Compare 

func (name Name) Compare(other Name) int

Compare returns negative when name<other, zero when name==other, positive when name>other.

func (Name) Equal 

func (name Name) Equal(other Name) bool

Equal determines whether two names are the same.

func (Name) Get 

func (name Name) Get(i int) NameComponent

Get returns i-th component. If negative, count from the end. If out-of-range, return invalid NameComponent.

func (Name) GetPrefix 

func (name Name) GetPrefix(i int) Name

GetPrefix returns a prefix of i components. If negative, count from the end.

func (Name) IsPrefixOf 

func (name Name) IsPrefixOf(other Name) bool

IsPrefixOf returns true if this name is a prefix of other name.

func (Name) Length 

func (name Name) Length() int

Length returns TLV-LENGTH. Use len(name) to get number of components.

func (Name) MarshalBinary 

func (name Name) MarshalBinary() (value []byte, e error)

MarshalBinary encodes TLV-VALUE of this name.

func (Name) MarshalText 

func (name Name) MarshalText() (text []byte, e error)

MarshalText implements encoding.TextMarshaler interface.

func (Name) MarshalTlv 

func (name Name) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this name.

func (Name) Slice 

func (name Name) Slice(i int, j ...int) Name

Slice returns a sub name between i-th (inclusive) and j-th (exclusive) components. j is optional; the default is toward the end. If negative, count from the end. If out-of-range, return empty name.

func (Name) String 

func (name Name) String() string

String returns URI representation of this name.

func (*Name) UnmarshalBinary 

func (name *Name) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes TLV-VALUE from wire format.

func (*Name) UnmarshalText 

func (name *Name) UnmarshalText(text []byte) error

UnmarshalText implements encoding.TextUnmarshaler interface.

type NameComponent 

type NameComponent struct {
	tlv.Element
}

NameComponent represents a name component. The zero NameComponent is invalid.

func MakeNameComponent 

func MakeNameComponent(typ uint32, value []byte) (comp NameComponent)

MakeNameComponent constructs a NameComponent from TLV-TYPE and TLV-VALUE.

func ParseNameComponent 

func ParseNameComponent(input string) (comp NameComponent)

ParseNameComponent parses URI representation of name component. It uses best effort and can accept any input.

func (NameComponent) Compare 

func (comp NameComponent) Compare(other NameComponent) int

Compare returns negative when comp<other, zero when comp==other, positive when comp>other.

func (NameComponent) Equal 

func (comp NameComponent) Equal(other NameComponent) bool

Equal determines whether two components are the same.

func (NameComponent) MarshalTlv 

func (comp NameComponent) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this component.

func (NameComponent) String 

func (comp NameComponent) String() string

String returns URI representation of this component.

func (*NameComponent) UnmarshalTlv 

func (comp *NameComponent) UnmarshalTlv(typ uint32, value []byte) error

UnmarshalTlv decodes from wire format.

func (NameComponent) Valid 

func (comp NameComponent) Valid() bool

Valid checks whether this component has a valid TLV-TYPE.

type Nonce 

type Nonce [4]byte

Nonce represents an Interest Nonce.

func NewNonce 

func NewNonce() (nonce Nonce)

NewNonce generates a random Nonce.

func NonceFromUint 

func NonceFromUint(n uint32) (nonce Nonce)

NonceFromUint converts uint32 to Nonce, interpreted as big endian.

func (Nonce) IsZero 

func (nonce Nonce) IsZero() bool

IsZero returns true if the nonce is zero.

func (Nonce) MarshalTlv 

func (nonce Nonce) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this Nonce.

func (Nonce) ToUint 

func (nonce Nonce) ToUint() uint32

ToUint converts Nonce to uint32, interpreted as big endian.

func (*Nonce) UnmarshalBinary 

func (nonce *Nonce) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from wire encoding.

type Packet 

type Packet struct {
	Lp LpL3

	Interest *Interest
	Data     *Data
	// contains filtered or unexported fields
}

Packet represents an NDN layer 3 packet with associated LpL3.

func (*Packet) MarshalTlv 

func (pkt *Packet) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this packet.

func (*Packet) String 

func (pkt *Packet) String() string

func (*Packet) ToPacket 

func (pkt *Packet) ToPacket() *Packet

ToPacket returns self.

func (*Packet) UnmarshalTlv 

func (pkt *Packet) UnmarshalTlv(typ uint32, value []byte) error

UnmarshalTlv decodes from wire format.

type PrefixAnnouncement 

type PrefixAnnouncement struct {
	ExpirationPeriod int
	ValidityPeriod   ValidityPeriod
}

PrefixAnnouncement holds the Content field of a prefix announcement object.

func (PrefixAnnouncement) MarshalTlv 

func (a PrefixAnnouncement) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this PrefixAnnouncment.

type SelfLearningHeaders 

type SelfLearningHeaders struct {
	NonDiscovery       bool
	PrefixAnnouncement Data
}

SelfLearningHeaders represents frame headers for self-learning.

func (SelfLearningHeaders) Empty 

func (slh SelfLearningHeaders) Empty() bool

Empty returns true if SelfLearningHeaders has zero fields.

func (SelfLearningHeaders) Encode 

func (slh SelfLearningHeaders) Encode() (fields []interface{}, err error)

Encode encodes the self-learning headers

type SigInfo 

type SigInfo struct {
	Type       uint32
	KeyLocator KeyLocator
	Nonce      []byte
	Time       uint64
	SeqNum     uint64
	Extensions []tlv.Element
}

SigInfo represents SignatureInfo on Interest or Data.

func (*SigInfo) EncodeAs 

func (si *SigInfo) EncodeAs(typ uint32) tlv.Marshaler

EncodeAs creates an encodable object for either ISigInfo or DSigInfo TLV-TYPE. If si is nil, the encoding result contains SigType=SigNull.

func (SigInfo) String 

func (si SigInfo) String() string

func (*SigInfo) UnmarshalBinary 

func (si *SigInfo) UnmarshalBinary(wire []byte) error

UnmarshalBinary decodes from TLV-VALUE.

type Signable 

type Signable interface {
	SignWith(signer func(name Name, si *SigInfo) (LLSign, error)) error
}

Signable is a packet that can be signed.

type SignableVerifiable 

type SignableVerifiable interface {
	Signable
	Verifiable
}

SignableVerifiable is both Signable and Verifiable.

type Signer 

type Signer interface {
	Sign(packet Signable) error
}

Signer is high-level signer, such as a private key. 

var NullSigner Signer = nullSigner{}

NullSigner implements Signer for SigNull signature type.

type SignerVerifier 

type SignerVerifier interface {
	Signer
	Verifier
}

SignerVerifier is both Signer and Verifier. 

var DigestSigning SignerVerifier = digestSigning{}

DigestSigning implements Signer and Verifier for SigSha256 signature type.

type ValidityPeriod 

type ValidityPeriod struct {
	NotBefore []byte
	NotAfter  []byte
}

ValidityPeriod contains two timestamps indicating a temporal range of validity.

func (ValidityPeriod) MarshalTlv 

func (v ValidityPeriod) MarshalTlv() (typ uint32, value []byte, e error)

MarshalTlv encodes this ValidityPeriod.

type Verifiable 

type Verifiable interface {
	VerifyWith(verifier func(name Name, si SigInfo) (LLVerify, error)) error
}

Verifiable is a packet that can be verified.

type Verifier 

type Verifier interface {
	Verify(packet Verifiable) error
}

Verifier is high-level verifier, such as a public key. 

var NopVerifier Verifier = nopVerifier{}

NopVerifier is a Verifier that performs no verification.

Source Files

View all Source files

Directories

Path Synopsis
Package an contains Assigned Numbers in Named Data Networking (NDN).
 Package an contains Assigned Numbers in Named Data Networking (NDN).
Package keychain implements signing and verification on NDN packets.
 Package keychain implements signing and verification on NDN packets.
eckey
Package eckey implements SigSha256WithEcdsa signature type.
 Package eckey implements SigSha256WithEcdsa signature type.
rsakey
Package rsakey implements SigSha256WithRsa signature type.
 Package rsakey implements SigSha256WithRsa signature type.
Package l3 defines a network layer face abstraction.
 Package l3 defines a network layer face abstraction.
Package ndntestenv contains helper functions to validate NDN packets in test code.
 Package ndntestenv contains helper functions to validate NDN packets in test code.
Package ndntestvector contains test vectors of NDN packets.
 Package ndntestvector contains test vectors of NDN packets.
Package tlv implements Type-Length-Value (TLV) encoding in Named Data Networking (NDN).
 Package tlv implements Type-Length-Value (TLV) encoding in Named Data Networking (NDN).

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