Files
mochi-mqtt/packets/properties.go
2023-05-04 22:37:23 +01:00

478 lines
17 KiB
Go

// SPDX-License-Identifier: MIT
// SPDX-FileCopyrightText: 2022 mochi-co
// SPDX-FileContributor: mochi-co
package packets
import (
"bytes"
"fmt"
"strings"
)
const (
PropPayloadFormat byte = 1
PropMessageExpiryInterval byte = 2
PropContentType byte = 3
PropResponseTopic byte = 8
PropCorrelationData byte = 9
PropSubscriptionIdentifier byte = 11
PropSessionExpiryInterval byte = 17
PropAssignedClientID byte = 18
PropServerKeepAlive byte = 19
PropAuthenticationMethod byte = 21
PropAuthenticationData byte = 22
PropRequestProblemInfo byte = 23
PropWillDelayInterval byte = 24
PropRequestResponseInfo byte = 25
PropResponseInfo byte = 26
PropServerReference byte = 28
PropReasonString byte = 31
PropReceiveMaximum byte = 33
PropTopicAliasMaximum byte = 34
PropTopicAlias byte = 35
PropMaximumQos byte = 36
PropRetainAvailable byte = 37
PropUser byte = 38
PropMaximumPacketSize byte = 39
PropWildcardSubAvailable byte = 40
PropSubIDAvailable byte = 41
PropSharedSubAvailable byte = 42
)
// validPacketProperties indicates which properties are valid for which packet types.
var validPacketProperties = map[byte]map[byte]byte{
PropPayloadFormat: {Publish: 1, WillProperties: 1},
PropMessageExpiryInterval: {Publish: 1, WillProperties: 1},
PropContentType: {Publish: 1, WillProperties: 1},
PropResponseTopic: {Publish: 1, WillProperties: 1},
PropCorrelationData: {Publish: 1, WillProperties: 1},
PropSubscriptionIdentifier: {Publish: 1, Subscribe: 1},
PropSessionExpiryInterval: {Connect: 1, Connack: 1, Disconnect: 1},
PropAssignedClientID: {Connack: 1},
PropServerKeepAlive: {Connack: 1},
PropAuthenticationMethod: {Connect: 1, Connack: 1, Auth: 1},
PropAuthenticationData: {Connect: 1, Connack: 1, Auth: 1},
PropRequestProblemInfo: {Connect: 1},
PropWillDelayInterval: {WillProperties: 1},
PropRequestResponseInfo: {Connect: 1},
PropResponseInfo: {Connack: 1},
PropServerReference: {Connack: 1, Disconnect: 1},
PropReasonString: {Connack: 1, Puback: 1, Pubrec: 1, Pubrel: 1, Pubcomp: 1, Suback: 1, Unsuback: 1, Disconnect: 1, Auth: 1},
PropReceiveMaximum: {Connect: 1, Connack: 1},
PropTopicAliasMaximum: {Connect: 1, Connack: 1},
PropTopicAlias: {Publish: 1},
PropMaximumQos: {Connack: 1},
PropRetainAvailable: {Connack: 1},
PropUser: {Connect: 1, Connack: 1, Publish: 1, Puback: 1, Pubrec: 1, Pubrel: 1, Pubcomp: 1, Subscribe: 1, Suback: 1, Unsubscribe: 1, Unsuback: 1, Disconnect: 1, Auth: 1, WillProperties: 1},
PropMaximumPacketSize: {Connect: 1, Connack: 1},
PropWildcardSubAvailable: {Connack: 1},
PropSubIDAvailable: {Connack: 1},
PropSharedSubAvailable: {Connack: 1},
}
// UserProperty is an arbitrary key-value pair for a packet user properties array.
type UserProperty struct { // [MQTT-1.5.7-1]
Key string `json:"k"`
Val string `json:"v"`
}
// Properties contains all of the mqtt v5 properties available for a packet.
// Some properties have valid values of 0 or not-present. In this case, we opt for
// property flags to indicate the usage of property.
// Refer to mqtt v5 2.2.2.2 Property spec for more information.
type Properties struct {
CorrelationData []byte `json:"cd"`
SubscriptionIdentifier []int `json:"si"`
AuthenticationData []byte `json:"ad"`
User []UserProperty `json:"user"`
ContentType string `json:"ct"`
ResponseTopic string `json:"rt"`
AssignedClientID string `json:"aci"`
AuthenticationMethod string `json:"am"`
ResponseInfo string `json:"ri"`
ServerReference string `json:"sr"`
ReasonString string `json:"rs"`
MessageExpiryInterval uint32 `json:"me"`
SessionExpiryInterval uint32 `json:"sei"`
WillDelayInterval uint32 `json:"wdi"`
MaximumPacketSize uint32 `json:"mps"`
ServerKeepAlive uint16 `json:"ska"`
ReceiveMaximum uint16 `json:"rm"`
TopicAliasMaximum uint16 `json:"tam"`
TopicAlias uint16 `json:"ta"`
PayloadFormat byte `json:"pf"`
PayloadFormatFlag bool `json:"fpf"`
SessionExpiryIntervalFlag bool `json:"fsei"`
ServerKeepAliveFlag bool `json:"fska"`
RequestProblemInfo byte `json:"rpi"`
RequestProblemInfoFlag bool `json:"frpi"`
RequestResponseInfo byte `json:"rri"`
TopicAliasFlag bool `json:"fta"`
MaximumQos byte `json:"mqos"`
MaximumQosFlag bool `json:"fmqos"`
RetainAvailable byte `json:"ra"`
RetainAvailableFlag bool `json:"fra"`
WildcardSubAvailable byte `json:"wsa"`
WildcardSubAvailableFlag bool `json:"fwsa"`
SubIDAvailable byte `json:"sida"`
SubIDAvailableFlag bool `json:"fsida"`
SharedSubAvailable byte `json:"ssa"`
SharedSubAvailableFlag bool `json:"fssa"`
}
// Copy creates a new Properties struct with copies of the values.
func (p *Properties) Copy(allowTransfer bool) Properties {
pr := Properties{
PayloadFormat: p.PayloadFormat, // [MQTT-3.3.2-4]
PayloadFormatFlag: p.PayloadFormatFlag,
MessageExpiryInterval: p.MessageExpiryInterval,
ContentType: p.ContentType, // [MQTT-3.3.2-20]
ResponseTopic: p.ResponseTopic, // [MQTT-3.3.2-15]
SessionExpiryInterval: p.SessionExpiryInterval,
SessionExpiryIntervalFlag: p.SessionExpiryIntervalFlag,
AssignedClientID: p.AssignedClientID,
ServerKeepAlive: p.ServerKeepAlive,
ServerKeepAliveFlag: p.ServerKeepAliveFlag,
AuthenticationMethod: p.AuthenticationMethod,
RequestProblemInfo: p.RequestProblemInfo,
RequestProblemInfoFlag: p.RequestProblemInfoFlag,
WillDelayInterval: p.WillDelayInterval,
RequestResponseInfo: p.RequestResponseInfo,
ResponseInfo: p.ResponseInfo,
ServerReference: p.ServerReference,
ReasonString: p.ReasonString,
ReceiveMaximum: p.ReceiveMaximum,
TopicAliasMaximum: p.TopicAliasMaximum,
TopicAlias: 0, // NB; do not copy topic alias [MQTT-3.3.2-7] + we do not send to clients (currently) [MQTT-3.1.2-26] [MQTT-3.1.2-27]
MaximumQos: p.MaximumQos,
MaximumQosFlag: p.MaximumQosFlag,
RetainAvailable: p.RetainAvailable,
RetainAvailableFlag: p.RetainAvailableFlag,
MaximumPacketSize: p.MaximumPacketSize,
WildcardSubAvailable: p.WildcardSubAvailable,
WildcardSubAvailableFlag: p.WildcardSubAvailableFlag,
SubIDAvailable: p.SubIDAvailable,
SubIDAvailableFlag: p.SubIDAvailableFlag,
SharedSubAvailable: p.SharedSubAvailable,
SharedSubAvailableFlag: p.SharedSubAvailableFlag,
}
if allowTransfer {
pr.TopicAlias = p.TopicAlias
pr.TopicAliasFlag = p.TopicAliasFlag
}
if len(p.CorrelationData) > 0 {
pr.CorrelationData = append([]byte{}, p.CorrelationData...) // [MQTT-3.3.2-16]
}
if len(p.SubscriptionIdentifier) > 0 {
pr.SubscriptionIdentifier = append([]int{}, p.SubscriptionIdentifier...)
}
if len(p.AuthenticationData) > 0 {
pr.AuthenticationData = append([]byte{}, p.AuthenticationData...)
}
if len(p.User) > 0 {
pr.User = []UserProperty{}
for _, v := range p.User {
pr.User = append(pr.User, UserProperty{ // [MQTT-3.3.2-17]
Key: v.Key,
Val: v.Val,
})
}
}
return pr
}
// canEncode returns true if the property type is valid for the packet type.
func (p *Properties) canEncode(pkt byte, k byte) bool {
return validPacketProperties[k][pkt] == 1
}
// Encode encodes properties into a bytes buffer.
func (p *Properties) Encode(pkt byte, mods Mods, b *bytes.Buffer, n int) {
if p == nil {
return
}
var buf bytes.Buffer
if p.canEncode(pkt, PropPayloadFormat) && p.PayloadFormatFlag {
buf.WriteByte(PropPayloadFormat)
buf.WriteByte(p.PayloadFormat)
}
if p.canEncode(pkt, PropMessageExpiryInterval) && p.MessageExpiryInterval > 0 {
buf.WriteByte(PropMessageExpiryInterval)
buf.Write(encodeUint32(p.MessageExpiryInterval))
}
if p.canEncode(pkt, PropContentType) && p.ContentType != "" {
buf.WriteByte(PropContentType)
buf.Write(encodeString(p.ContentType)) // [MQTT-3.3.2-19]
}
if mods.AllowResponseInfo && p.canEncode(pkt, PropResponseTopic) && // [MQTT-3.3.2-14]
p.ResponseTopic != "" && !strings.ContainsAny(p.ResponseTopic, "+#") { // [MQTT-3.1.2-28]
buf.WriteByte(PropResponseTopic)
buf.Write(encodeString(p.ResponseTopic)) // [MQTT-3.3.2-13]
}
if mods.AllowResponseInfo && p.canEncode(pkt, PropCorrelationData) && len(p.CorrelationData) > 0 { // [MQTT-3.1.2-28]
buf.WriteByte(PropCorrelationData)
buf.Write(encodeBytes(p.CorrelationData))
}
if p.canEncode(pkt, PropSubscriptionIdentifier) && len(p.SubscriptionIdentifier) > 0 {
for _, v := range p.SubscriptionIdentifier {
if v > 0 {
buf.WriteByte(PropSubscriptionIdentifier)
encodeLength(&buf, int64(v))
}
}
}
if p.canEncode(pkt, PropSessionExpiryInterval) && p.SessionExpiryIntervalFlag { // [MQTT-3.14.2-2]
buf.WriteByte(PropSessionExpiryInterval)
buf.Write(encodeUint32(p.SessionExpiryInterval))
}
if p.canEncode(pkt, PropAssignedClientID) && p.AssignedClientID != "" {
buf.WriteByte(PropAssignedClientID)
buf.Write(encodeString(p.AssignedClientID))
}
if p.canEncode(pkt, PropServerKeepAlive) && p.ServerKeepAliveFlag {
buf.WriteByte(PropServerKeepAlive)
buf.Write(encodeUint16(p.ServerKeepAlive))
}
if p.canEncode(pkt, PropAuthenticationMethod) && p.AuthenticationMethod != "" {
buf.WriteByte(PropAuthenticationMethod)
buf.Write(encodeString(p.AuthenticationMethod))
}
if p.canEncode(pkt, PropAuthenticationData) && len(p.AuthenticationData) > 0 {
buf.WriteByte(PropAuthenticationData)
buf.Write(encodeBytes(p.AuthenticationData))
}
if p.canEncode(pkt, PropRequestProblemInfo) && p.RequestProblemInfoFlag {
buf.WriteByte(PropRequestProblemInfo)
buf.WriteByte(p.RequestProblemInfo)
}
if p.canEncode(pkt, PropWillDelayInterval) && p.WillDelayInterval > 0 {
buf.WriteByte(PropWillDelayInterval)
buf.Write(encodeUint32(p.WillDelayInterval))
}
if p.canEncode(pkt, PropRequestResponseInfo) && p.RequestResponseInfo > 0 {
buf.WriteByte(PropRequestResponseInfo)
buf.WriteByte(p.RequestResponseInfo)
}
if mods.AllowResponseInfo && p.canEncode(pkt, PropResponseInfo) && len(p.ResponseInfo) > 0 { // [MQTT-3.1.2-28]
buf.WriteByte(PropResponseInfo)
buf.Write(encodeString(p.ResponseInfo))
}
if p.canEncode(pkt, PropServerReference) && len(p.ServerReference) > 0 {
buf.WriteByte(PropServerReference)
buf.Write(encodeString(p.ServerReference))
}
// [MQTT-3.2.2-19] [MQTT-3.14.2-3] [MQTT-3.4.2-2] [MQTT-3.5.2-2]
// [MQTT-3.6.2-2] [MQTT-3.9.2-1] [MQTT-3.11.2-1] [MQTT-3.15.2-2]
if !mods.DisallowProblemInfo && p.canEncode(pkt, PropReasonString) && p.ReasonString != "" {
b := encodeString(p.ReasonString)
if mods.MaxSize == 0 || uint32(n+len(b)+1) < mods.MaxSize {
buf.WriteByte(PropReasonString)
buf.Write(b)
}
}
if p.canEncode(pkt, PropReceiveMaximum) && p.ReceiveMaximum > 0 {
buf.WriteByte(PropReceiveMaximum)
buf.Write(encodeUint16(p.ReceiveMaximum))
}
if p.canEncode(pkt, PropTopicAliasMaximum) && p.TopicAliasMaximum > 0 {
buf.WriteByte(PropTopicAliasMaximum)
buf.Write(encodeUint16(p.TopicAliasMaximum))
}
if p.canEncode(pkt, PropTopicAlias) && p.TopicAliasFlag && p.TopicAlias > 0 { // [MQTT-3.3.2-8]
buf.WriteByte(PropTopicAlias)
buf.Write(encodeUint16(p.TopicAlias))
}
if p.canEncode(pkt, PropMaximumQos) && p.MaximumQosFlag && p.MaximumQos < 2 {
buf.WriteByte(PropMaximumQos)
buf.WriteByte(p.MaximumQos)
}
if p.canEncode(pkt, PropRetainAvailable) && p.RetainAvailableFlag {
buf.WriteByte(PropRetainAvailable)
buf.WriteByte(p.RetainAvailable)
}
if !mods.DisallowProblemInfo && p.canEncode(pkt, PropUser) {
pb := bytes.NewBuffer([]byte{})
for _, v := range p.User {
pb.WriteByte(PropUser)
pb.Write(encodeString(v.Key))
pb.Write(encodeString(v.Val))
}
// [MQTT-3.2.2-20] [MQTT-3.14.2-4] [MQTT-3.4.2-3] [MQTT-3.5.2-3]
// [MQTT-3.6.2-3] [MQTT-3.9.2-2] [MQTT-3.11.2-2] [MQTT-3.15.2-3]
if mods.MaxSize == 0 || uint32(n+pb.Len()+1) < mods.MaxSize {
buf.Write(pb.Bytes())
}
}
if p.canEncode(pkt, PropMaximumPacketSize) && p.MaximumPacketSize > 0 {
buf.WriteByte(PropMaximumPacketSize)
buf.Write(encodeUint32(p.MaximumPacketSize))
}
if p.canEncode(pkt, PropWildcardSubAvailable) && p.WildcardSubAvailableFlag {
buf.WriteByte(PropWildcardSubAvailable)
buf.WriteByte(p.WildcardSubAvailable)
}
if p.canEncode(pkt, PropSubIDAvailable) && p.SubIDAvailableFlag {
buf.WriteByte(PropSubIDAvailable)
buf.WriteByte(p.SubIDAvailable)
}
if p.canEncode(pkt, PropSharedSubAvailable) && p.SharedSubAvailableFlag {
buf.WriteByte(PropSharedSubAvailable)
buf.WriteByte(p.SharedSubAvailable)
}
encodeLength(b, int64(buf.Len()))
buf.WriteTo(b) // [MQTT-3.1.3-10]
}
// Decode decodes property bytes into a properties struct.
func (p *Properties) Decode(pkt byte, b *bytes.Buffer) (n int, err error) {
if p == nil {
return 0, nil
}
var bu int
n, bu, err = DecodeLength(b)
if err != nil {
return n + bu, err
}
if n == 0 {
return n + bu, nil
}
bt := b.Bytes()
var k byte
for offset := 0; offset < n; {
k, offset, err = decodeByte(bt, offset)
if err != nil {
return n + bu, err
}
if _, ok := validPacketProperties[k][pkt]; !ok {
return n + bu, fmt.Errorf("property type %v not valid for packet type %v: %w", k, pkt, ErrProtocolViolationUnsupportedProperty)
}
switch k {
case PropPayloadFormat:
p.PayloadFormat, offset, err = decodeByte(bt, offset)
p.PayloadFormatFlag = true
case PropMessageExpiryInterval:
p.MessageExpiryInterval, offset, err = decodeUint32(bt, offset)
case PropContentType:
p.ContentType, offset, err = decodeString(bt, offset)
case PropResponseTopic:
p.ResponseTopic, offset, err = decodeString(bt, offset)
case PropCorrelationData:
p.CorrelationData, offset, err = decodeBytes(bt, offset)
case PropSubscriptionIdentifier:
if p.SubscriptionIdentifier == nil {
p.SubscriptionIdentifier = []int{}
}
n, bu, err := DecodeLength(bytes.NewBuffer(bt[offset:]))
if err != nil {
return n + bu, err
}
p.SubscriptionIdentifier = append(p.SubscriptionIdentifier, n)
offset += bu
case PropSessionExpiryInterval:
p.SessionExpiryInterval, offset, err = decodeUint32(bt, offset)
p.SessionExpiryIntervalFlag = true
case PropAssignedClientID:
p.AssignedClientID, offset, err = decodeString(bt, offset)
case PropServerKeepAlive:
p.ServerKeepAlive, offset, err = decodeUint16(bt, offset)
p.ServerKeepAliveFlag = true
case PropAuthenticationMethod:
p.AuthenticationMethod, offset, err = decodeString(bt, offset)
case PropAuthenticationData:
p.AuthenticationData, offset, err = decodeBytes(bt, offset)
case PropRequestProblemInfo:
p.RequestProblemInfo, offset, err = decodeByte(bt, offset)
p.RequestProblemInfoFlag = true
case PropWillDelayInterval:
p.WillDelayInterval, offset, err = decodeUint32(bt, offset)
case PropRequestResponseInfo:
p.RequestResponseInfo, offset, err = decodeByte(bt, offset)
case PropResponseInfo:
p.ResponseInfo, offset, err = decodeString(bt, offset)
case PropServerReference:
p.ServerReference, offset, err = decodeString(bt, offset)
case PropReasonString:
p.ReasonString, offset, err = decodeString(bt, offset)
case PropReceiveMaximum:
p.ReceiveMaximum, offset, err = decodeUint16(bt, offset)
case PropTopicAliasMaximum:
p.TopicAliasMaximum, offset, err = decodeUint16(bt, offset)
case PropTopicAlias:
p.TopicAlias, offset, err = decodeUint16(bt, offset)
p.TopicAliasFlag = true
case PropMaximumQos:
p.MaximumQos, offset, err = decodeByte(bt, offset)
p.MaximumQosFlag = true
case PropRetainAvailable:
p.RetainAvailable, offset, err = decodeByte(bt, offset)
p.RetainAvailableFlag = true
case PropUser:
var k, v string
k, offset, err = decodeString(bt, offset)
if err != nil {
return n + bu, err
}
v, offset, err = decodeString(bt, offset)
p.User = append(p.User, UserProperty{Key: k, Val: v})
case PropMaximumPacketSize:
p.MaximumPacketSize, offset, err = decodeUint32(bt, offset)
case PropWildcardSubAvailable:
p.WildcardSubAvailable, offset, err = decodeByte(bt, offset)
p.WildcardSubAvailableFlag = true
case PropSubIDAvailable:
p.SubIDAvailable, offset, err = decodeByte(bt, offset)
p.SubIDAvailableFlag = true
case PropSharedSubAvailable:
p.SharedSubAvailable, offset, err = decodeByte(bt, offset)
p.SharedSubAvailableFlag = true
}
if err != nil {
return n + bu, err
}
}
return n + bu, nil
}