255 lines
8.1 KiB
Go
255 lines
8.1 KiB
Go
// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
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// SPDX-License-Identifier: MIT
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package stun
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import (
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"errors"
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"fmt"
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)
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// Attributes is list of message attributes.
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type Attributes []RawAttribute
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// Get returns first attribute from list by the type.
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// If attribute is present the RawAttribute is returned and the
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// boolean is true. Otherwise the returned RawAttribute will be
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// empty and boolean will be false.
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func (a Attributes) Get(t AttrType) (RawAttribute, bool) {
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for _, candidate := range a {
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if candidate.Type == t {
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return candidate, true
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}
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}
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return RawAttribute{}, false
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}
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// AttrType is attribute type.
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type AttrType uint16
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// Required returns true if type is from comprehension-required range (0x0000-0x7FFF).
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func (t AttrType) Required() bool {
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return t <= 0x7FFF
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}
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// Optional returns true if type is from comprehension-optional range (0x8000-0xFFFF).
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func (t AttrType) Optional() bool {
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return t >= 0x8000
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}
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// Attributes from comprehension-required range (0x0000-0x7FFF).
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const (
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AttrMappedAddress AttrType = 0x0001 // MAPPED-ADDRESS
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AttrUsername AttrType = 0x0006 // USERNAME
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AttrMessageIntegrity AttrType = 0x0008 // MESSAGE-INTEGRITY
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AttrErrorCode AttrType = 0x0009 // ERROR-CODE
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AttrUnknownAttributes AttrType = 0x000A // UNKNOWN-ATTRIBUTES
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AttrRealm AttrType = 0x0014 // REALM
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AttrNonce AttrType = 0x0015 // NONCE
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AttrXORMappedAddress AttrType = 0x0020 // XOR-MAPPED-ADDRESS
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)
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// Attributes from comprehension-optional range (0x8000-0xFFFF).
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const (
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AttrSoftware AttrType = 0x8022 // SOFTWARE
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AttrAlternateServer AttrType = 0x8023 // ALTERNATE-SERVER
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AttrFingerprint AttrType = 0x8028 // FINGERPRINT
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)
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// Attributes from RFC 5245 ICE.
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const (
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AttrPriority AttrType = 0x0024 // PRIORITY
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AttrUseCandidate AttrType = 0x0025 // USE-CANDIDATE
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AttrICEControlled AttrType = 0x8029 // ICE-CONTROLLED
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AttrICEControlling AttrType = 0x802A // ICE-CONTROLLING
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)
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// Attributes from RFC 5766 TURN.
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const (
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AttrChannelNumber AttrType = 0x000C // CHANNEL-NUMBER
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AttrLifetime AttrType = 0x000D // LIFETIME
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AttrXORPeerAddress AttrType = 0x0012 // XOR-PEER-ADDRESS
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AttrData AttrType = 0x0013 // DATA
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AttrXORRelayedAddress AttrType = 0x0016 // XOR-RELAYED-ADDRESS
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AttrEvenPort AttrType = 0x0018 // EVEN-PORT
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AttrRequestedTransport AttrType = 0x0019 // REQUESTED-TRANSPORT
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AttrDontFragment AttrType = 0x001A // DONT-FRAGMENT
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AttrReservationToken AttrType = 0x0022 // RESERVATION-TOKEN
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)
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// Attributes from RFC 5780 NAT Behavior Discovery
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const (
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AttrChangeRequest AttrType = 0x0003 // CHANGE-REQUEST
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AttrPadding AttrType = 0x0026 // PADDING
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AttrResponsePort AttrType = 0x0027 // RESPONSE-PORT
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AttrCacheTimeout AttrType = 0x8027 // CACHE-TIMEOUT
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AttrResponseOrigin AttrType = 0x802b // RESPONSE-ORIGIN
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AttrOtherAddress AttrType = 0x802C // OTHER-ADDRESS
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)
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// Attributes from RFC 3489, removed by RFC 5389,
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//
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// but still used by RFC5389-implementing software like Vovida.org, reTURNServer, etc.
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const (
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AttrSourceAddress AttrType = 0x0004 // SOURCE-ADDRESS
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AttrChangedAddress AttrType = 0x0005 // CHANGED-ADDRESS
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)
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// Attributes from RFC 6062 TURN Extensions for TCP Allocations.
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const (
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AttrConnectionID AttrType = 0x002a // CONNECTION-ID
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)
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// Attributes from RFC 6156 TURN IPv6.
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const (
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AttrRequestedAddressFamily AttrType = 0x0017 // REQUESTED-ADDRESS-FAMILY
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)
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// Attributes from An Origin Attribute for the STUN Protocol.
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const (
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AttrOrigin AttrType = 0x802F
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)
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// Attributes from RFC 8489 STUN.
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const (
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AttrMessageIntegritySHA256 AttrType = 0x001C // MESSAGE-INTEGRITY-SHA256
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AttrPasswordAlgorithm AttrType = 0x001D // PASSWORD-ALGORITHM
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AttrUserhash AttrType = 0x001E // USERHASH
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AttrPasswordAlgorithms AttrType = 0x8002 // PASSWORD-ALGORITHMS
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AttrAlternateDomain AttrType = 0x8003 // ALTERNATE-DOMAIN
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)
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// Value returns uint16 representation of attribute type.
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func (t AttrType) Value() uint16 {
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return uint16(t)
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}
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func attrNames() map[AttrType]string {
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return map[AttrType]string{
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AttrMappedAddress: "MAPPED-ADDRESS",
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AttrUsername: "USERNAME",
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AttrErrorCode: "ERROR-CODE",
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AttrMessageIntegrity: "MESSAGE-INTEGRITY",
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AttrUnknownAttributes: "UNKNOWN-ATTRIBUTES",
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AttrRealm: "REALM",
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AttrNonce: "NONCE",
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AttrXORMappedAddress: "XOR-MAPPED-ADDRESS",
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AttrSoftware: "SOFTWARE",
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AttrAlternateServer: "ALTERNATE-SERVER",
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AttrFingerprint: "FINGERPRINT",
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AttrPriority: "PRIORITY",
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AttrUseCandidate: "USE-CANDIDATE",
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AttrICEControlled: "ICE-CONTROLLED",
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AttrICEControlling: "ICE-CONTROLLING",
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AttrChannelNumber: "CHANNEL-NUMBER",
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AttrLifetime: "LIFETIME",
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AttrXORPeerAddress: "XOR-PEER-ADDRESS",
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AttrData: "DATA",
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AttrXORRelayedAddress: "XOR-RELAYED-ADDRESS",
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AttrEvenPort: "EVEN-PORT",
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AttrRequestedTransport: "REQUESTED-TRANSPORT",
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AttrDontFragment: "DONT-FRAGMENT",
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AttrReservationToken: "RESERVATION-TOKEN",
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AttrConnectionID: "CONNECTION-ID",
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AttrRequestedAddressFamily: "REQUESTED-ADDRESS-FAMILY",
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AttrMessageIntegritySHA256: "MESSAGE-INTEGRITY-SHA256",
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AttrPasswordAlgorithm: "PASSWORD-ALGORITHM",
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AttrUserhash: "USERHASH",
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AttrPasswordAlgorithms: "PASSWORD-ALGORITHMS",
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AttrAlternateDomain: "ALTERNATE-DOMAIN",
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}
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}
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func (t AttrType) String() string {
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s, ok := attrNames()[t]
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if !ok {
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// Just return hex representation of unknown attribute type.
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return fmt.Sprintf("0x%x", uint16(t))
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}
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return s
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}
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// RawAttribute is a Type-Length-Value (TLV) object that
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// can be added to a STUN message. Attributes are divided into two
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// types: comprehension-required and comprehension-optional. STUN
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// agents can safely ignore comprehension-optional attributes they
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// don't understand, but cannot successfully process a message if it
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// contains comprehension-required attributes that are not
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// understood.
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type RawAttribute struct {
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Type AttrType
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Length uint16 // ignored while encoding
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Value []byte
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}
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// AddTo implements Setter, adding attribute as a.Type with a.Value and ignoring
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// the Length field.
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func (a RawAttribute) AddTo(m *Message) error {
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m.Add(a.Type, a.Value)
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return nil
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}
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// Equal returns true if a == b.
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func (a RawAttribute) Equal(b RawAttribute) bool {
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if a.Type != b.Type {
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return false
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}
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if a.Length != b.Length {
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return false
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}
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if len(b.Value) != len(a.Value) {
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return false
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}
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for i, v := range a.Value {
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if b.Value[i] != v {
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return false
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}
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}
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return true
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}
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func (a RawAttribute) String() string {
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return fmt.Sprintf("%s: 0x%x", a.Type, a.Value)
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}
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// ErrAttributeNotFound means that attribute with provided attribute
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// type does not exist in message.
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var ErrAttributeNotFound = errors.New("attribute not found")
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// Get returns byte slice that represents attribute value,
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// if there is no attribute with such type,
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// ErrAttributeNotFound is returned.
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func (m *Message) Get(t AttrType) ([]byte, error) {
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v, ok := m.Attributes.Get(t)
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if !ok {
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return nil, ErrAttributeNotFound
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}
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return v.Value, nil
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}
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// STUN aligns attributes on 32-bit boundaries, attributes whose content
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// is not a multiple of 4 bytes are padded with 1, 2, or 3 bytes of
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// padding so that its value contains a multiple of 4 bytes. The
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// padding bits are ignored, and may be any value.
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//
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// https://tools.ietf.org/html/rfc5389#section-15
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const padding = 4
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func nearestPaddedValueLength(l int) int {
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n := padding * (l / padding)
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if n < l {
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n += padding
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}
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return n
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}
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// This method converts uint16 vlue to AttrType. If it finds an old attribute
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// type value, it also translates it to the new value to enable backward
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// compatibility. (See: https://github.com/pion/stun/issues/21)
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func compatAttrType(val uint16) AttrType {
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if val == 0x8020 { // draft-ietf-behave-rfc3489bis-02, MS-TURN
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return AttrXORMappedAddress // new: 0x0020 (from draft-ietf-behave-rfc3489bis-03 on)
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}
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return AttrType(val)
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}
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