/
conn.go
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/
conn.go
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package client
import (
"context"
"errors"
"fmt"
"net"
"time"
"github.com/plgd-dev/go-coap/v3/message"
"github.com/plgd-dev/go-coap/v3/message/codes"
"github.com/plgd-dev/go-coap/v3/message/pool"
coapNet "github.com/plgd-dev/go-coap/v3/net"
"github.com/plgd-dev/go-coap/v3/net/blockwise"
"github.com/plgd-dev/go-coap/v3/net/client"
limitparallelrequests "github.com/plgd-dev/go-coap/v3/net/client/limitParallelRequests"
"github.com/plgd-dev/go-coap/v3/net/monitor/inactivity"
"github.com/plgd-dev/go-coap/v3/net/observation"
"github.com/plgd-dev/go-coap/v3/net/responsewriter"
coapErrors "github.com/plgd-dev/go-coap/v3/pkg/errors"
coapSync "github.com/plgd-dev/go-coap/v3/pkg/sync"
"go.uber.org/atomic"
)
type InactivityMonitor interface {
Notify()
CheckInactivity(now time.Time, cc *Conn)
}
type (
HandlerFunc = func(*responsewriter.ResponseWriter[*Conn], *pool.Message)
ErrorFunc = func(error)
EventFunc = func()
GetMIDFunc = func() int32
CreateInactivityMonitorFunc = func() InactivityMonitor
RequestMonitorFunc = func(cc *Conn, req *pool.Message) (drop bool, err error)
)
type Notifier interface {
Notify()
}
// Conn represents a virtual connection to a conceptual endpoint, to perform COAPs commands.
type Conn struct {
*client.Client[*Conn]
session *Session
observationHandler *observation.Handler[*Conn]
processReceivedMessage func(req *pool.Message, cc *Conn, handler HandlerFunc)
tokenHandlerContainer *coapSync.Map[uint64, HandlerFunc]
blockWise *blockwise.BlockWise[*Conn]
blockwiseSZX blockwise.SZX
peerMaxMessageSize atomic.Uint32
disablePeerTCPSignalMessageCSMs bool
peerBlockWiseTranferEnabled atomic.Bool
receivedMessageReader *client.ReceivedMessageReader[*Conn]
}
type ConnOptions struct {
CreateBlockWise func(cc *Conn) *blockwise.BlockWise[*Conn]
InactivityMonitor InactivityMonitor
RequestMonitor RequestMonitorFunc
}
type Option = func(opts *ConnOptions)
// WithBlockWise enables block-wise transfer for the connection.
func WithBlockWise(createBlockWise func(cc *Conn) *blockwise.BlockWise[*Conn]) Option {
return func(opts *ConnOptions) {
opts.CreateBlockWise = createBlockWise
}
}
// WithInactivityMonitor enables inactivity monitor for the connection.
func WithInactivityMonitor(inactivityMonitor InactivityMonitor) Option {
return func(opts *ConnOptions) {
opts.InactivityMonitor = inactivityMonitor
}
}
// WithRequestMonitor enables request monitoring for the connection.
// It is called for each CoAP message received from the peer before it is processed.
// If it returns an error, the connection is closed.
// If it returns true, the message is dropped.
func WithRequestMonitor(requestMonitor RequestMonitorFunc) Option {
return func(opts *ConnOptions) {
opts.RequestMonitor = requestMonitor
}
}
// NewConn creates connection over session and observation.
func NewConn(
connection *coapNet.Conn,
createBlockWise func(cc *Conn) *blockwise.BlockWise[*Conn],
inactivityMonitor InactivityMonitor,
cfg *Config,
) *Conn {
return NewConnWithOpts(connection, cfg, WithBlockWise(createBlockWise), WithInactivityMonitor(inactivityMonitor))
}
func NewConnWithOpts(connection *coapNet.Conn, cfg *Config, opts ...Option) *Conn {
if cfg.GetToken == nil {
cfg.GetToken = message.GetToken
}
cfgOpts := ConnOptions{
CreateBlockWise: func(*Conn) *blockwise.BlockWise[*Conn] {
return nil
},
InactivityMonitor: inactivity.NewNilMonitor[*Conn](),
RequestMonitor: func(*Conn, *pool.Message) (bool, error) {
return false, nil
},
}
for _, o := range opts {
o(&cfgOpts)
}
cc := Conn{
tokenHandlerContainer: coapSync.NewMap[uint64, HandlerFunc](),
blockwiseSZX: cfg.BlockwiseSZX,
disablePeerTCPSignalMessageCSMs: cfg.DisablePeerTCPSignalMessageCSMs,
}
limitParallelRequests := limitparallelrequests.New(cfg.LimitClientParallelRequests, cfg.LimitClientEndpointParallelRequests, cc.do, cc.doObserve)
cc.observationHandler = observation.NewHandler(&cc, cfg.Handler, limitParallelRequests.Do)
cc.Client = client.New(&cc, cc.observationHandler, cfg.GetToken, limitParallelRequests)
cc.blockWise = cfgOpts.CreateBlockWise(&cc)
session := NewSession(cfg.Ctx,
connection,
cfg.MaxMessageSize,
cfg.Errors,
cfg.DisableTCPSignalMessageCSM,
cfg.CloseSocket,
cfgOpts.InactivityMonitor,
cfgOpts.RequestMonitor,
cfg.ConnectionCacheSize,
cfg.MessagePool,
)
cc.session = session
if cc.processReceivedMessage == nil {
cc.processReceivedMessage = processReceivedMessage
}
cc.receivedMessageReader = client.NewReceivedMessageReader(&cc, cfg.ReceivedMessageQueueSize)
return &cc
}
func processReceivedMessage(req *pool.Message, cc *Conn, handler HandlerFunc) {
cc.ProcessReceivedMessageWithHandler(req, handler)
}
func (cc *Conn) ProcessReceivedMessage(req *pool.Message) {
cc.processReceivedMessage(req, cc, cc.handle)
}
func (cc *Conn) Session() *Session {
return cc.session
}
// Close closes connection without wait of ends Run function.
func (cc *Conn) Close() error {
err := cc.session.Close()
if errors.Is(err, net.ErrClosed) {
return nil
}
return err
}
func (cc *Conn) doInternal(req *pool.Message) (*pool.Message, error) {
token := req.Token()
if token == nil {
return nil, fmt.Errorf("invalid token")
}
respChan := make(chan *pool.Message, 1)
if _, loaded := cc.tokenHandlerContainer.LoadOrStore(token.Hash(), func(_ *responsewriter.ResponseWriter[*Conn], r *pool.Message) {
r.Hijack()
select {
case respChan <- r:
default:
}
}); loaded {
return nil, fmt.Errorf("cannot add token handler: %w", coapErrors.ErrKeyAlreadyExists)
}
defer func() {
_, _ = cc.tokenHandlerContainer.LoadAndDelete(token.Hash())
}()
if err := cc.session.WriteMessage(req); err != nil {
return nil, fmt.Errorf("cannot write request: %w", err)
}
cc.receivedMessageReader.TryToReplaceLoop()
select {
case <-req.Context().Done():
return nil, req.Context().Err()
case <-cc.session.Context().Done():
return nil, fmt.Errorf("connection was closed: %w", cc.Context().Err())
case resp := <-respChan:
return resp, nil
}
}
// Do sends an coap message and returns an coap response.
//
// An error is returned if by failure to speak COAP (such as a network connectivity problem).
// Any status code doesn't cause an error.
//
// Caller is responsible to release request and response.
func (cc *Conn) do(req *pool.Message) (*pool.Message, error) {
if !cc.peerBlockWiseTranferEnabled.Load() || cc.blockWise == nil {
return cc.doInternal(req)
}
resp, err := cc.blockWise.Do(req, cc.blockwiseSZX, cc.session.maxMessageSize, cc.doInternal)
if err != nil {
return nil, err
}
return resp, nil
}
func (cc *Conn) writeMessage(req *pool.Message) error {
return cc.session.WriteMessage(req)
}
// WriteMessage sends an coap message.
func (cc *Conn) WriteMessage(req *pool.Message) error {
if !cc.peerBlockWiseTranferEnabled.Load() || cc.blockWise == nil {
return cc.writeMessage(req)
}
return cc.blockWise.WriteMessage(req, cc.blockwiseSZX, cc.Session().maxMessageSize, cc.writeMessage)
}
// Context returns the client's context.
//
// If connections was closed context is cancelled.
func (cc *Conn) Context() context.Context {
return cc.session.Context()
}
// AsyncPing sends ping and receivedPong will be called when pong arrives. It returns cancellation of ping operation.
func (cc *Conn) AsyncPing(receivedPong func()) (func(), error) {
token, err := message.GetToken()
if err != nil {
return nil, fmt.Errorf("cannot get token: %w", err)
}
req := cc.session.messagePool.AcquireMessage(cc.Context())
req.SetToken(token)
req.SetCode(codes.Ping)
defer cc.ReleaseMessage(req)
if _, loaded := cc.tokenHandlerContainer.LoadOrStore(token.Hash(), func(_ *responsewriter.ResponseWriter[*Conn], r *pool.Message) {
if r.Code() == codes.Pong {
receivedPong()
}
}); loaded {
return nil, fmt.Errorf("cannot add token handler: %w", coapErrors.ErrKeyAlreadyExists)
}
removeTokenHandler := func() {
_, _ = cc.tokenHandlerContainer.LoadAndDelete(token.Hash())
}
err = cc.session.WriteMessage(req)
if err != nil {
removeTokenHandler()
return nil, fmt.Errorf("cannot write request: %w", err)
}
return removeTokenHandler, nil
}
// Run reads and process requests from a connection, until the connection is not closed.
func (cc *Conn) Run() (err error) {
return cc.session.Run(cc)
}
// AddOnClose calls function on close connection event.
func (cc *Conn) AddOnClose(f EventFunc) {
cc.session.AddOnClose(f)
}
// RemoteAddr gets remote address.
func (cc *Conn) RemoteAddr() net.Addr {
return cc.session.RemoteAddr()
}
func (cc *Conn) LocalAddr() net.Addr {
return cc.session.LocalAddr()
}
// Sequence acquires sequence number.
func (cc *Conn) Sequence() uint64 {
return cc.session.Sequence()
}
// SetContextValue stores the value associated with key to context of connection.
func (cc *Conn) SetContextValue(key interface{}, val interface{}) {
cc.session.SetContextValue(key, val)
}
// Done signalizes that connection is not more processed.
func (cc *Conn) Done() <-chan struct{} {
return cc.session.Done()
}
// CheckExpirations checks and remove expired items from caches.
func (cc *Conn) CheckExpirations(now time.Time) {
cc.session.CheckExpirations(now, cc)
if cc.blockWise != nil {
cc.blockWise.CheckExpirations(now)
}
}
func (cc *Conn) AcquireMessage(ctx context.Context) *pool.Message {
return cc.session.AcquireMessage(ctx)
}
func (cc *Conn) ReleaseMessage(m *pool.Message) {
cc.session.ReleaseMessage(m)
}
// NetConn returns the underlying connection that is wrapped by cc. The Conn returned is shared by all invocations of NetConn, so do not modify it.
func (cc *Conn) NetConn() net.Conn {
return cc.session.NetConn()
}
// DoObserve subscribes for every change with request.
func (cc *Conn) doObserve(req *pool.Message, observeFunc func(req *pool.Message)) (client.Observation, error) {
return cc.observationHandler.NewObservation(req, observeFunc)
}
func (cc *Conn) ProcessReceivedMessageWithHandler(req *pool.Message, handler HandlerFunc) {
origResp := cc.AcquireMessage(cc.Context())
origResp.SetToken(req.Token())
w := responsewriter.New(origResp, cc, req.Options()...)
handler(w, req)
defer cc.ReleaseMessage(w.Message())
if !req.IsHijacked() {
cc.ReleaseMessage(req)
}
if w.Message().IsModified() {
err := cc.Session().WriteMessage(w.Message())
if err != nil {
if errC := cc.Close(); errC != nil {
cc.Session().errors(fmt.Errorf("cannot close connection: %w", errC))
}
cc.Session().errors(fmt.Errorf("cannot write response to %v: %w", cc.RemoteAddr(), err))
}
}
}
func (cc *Conn) blockwiseHandle(w *responsewriter.ResponseWriter[*Conn], r *pool.Message) {
if h, ok := cc.tokenHandlerContainer.Load(r.Token().Hash()); ok {
h(w, r)
return
}
cc.observationHandler.Handle(w, r)
}
func (cc *Conn) handle(w *responsewriter.ResponseWriter[*Conn], r *pool.Message) {
if cc.blockWise != nil && cc.peerBlockWiseTranferEnabled.Load() {
cc.blockWise.Handle(w, r, cc.blockwiseSZX, cc.Session().maxMessageSize, cc.blockwiseHandle)
return
}
if h, ok := cc.tokenHandlerContainer.LoadAndDelete(r.Token().Hash()); ok {
h(w, r)
return
}
cc.observationHandler.Handle(w, r)
}
func (cc *Conn) sendPong(token message.Token) error {
req := cc.AcquireMessage(cc.Context())
defer cc.ReleaseMessage(req)
req.SetCode(codes.Pong)
req.SetToken(token)
return cc.Session().WriteMessage(req)
}
func (cc *Conn) handleSignals(r *pool.Message) bool {
switch r.Code() {
case codes.CSM:
if cc.disablePeerTCPSignalMessageCSMs {
return true
}
if size, err := r.GetOptionUint32(message.TCPMaxMessageSize); err == nil {
cc.peerMaxMessageSize.Store(size)
}
if r.HasOption(message.TCPBlockWiseTransfer) {
cc.peerBlockWiseTranferEnabled.Store(true)
}
return true
case codes.Ping:
// if r.HasOption(message.TCPCustody) {
// TODO
// }
if err := cc.sendPong(r.Token()); err != nil && !coapNet.IsConnectionBrokenError(err) {
cc.Session().errors(fmt.Errorf("cannot handle ping signal: %w", err))
}
return true
case codes.Release:
// if r.HasOption(message.TCPAlternativeAddress) {
// TODO
// }
return true
case codes.Abort:
// if r.HasOption(message.TCPBadCSMOption) {
// TODO
// }
return true
case codes.Pong:
if h, ok := cc.tokenHandlerContainer.LoadAndDelete(r.Token().Hash()); ok {
cc.processReceivedMessage(r, cc, h)
}
return true
}
return false
}
func (cc *Conn) pushToReceivedMessageQueue(r *pool.Message) {
if cc.handleSignals(r) {
return
}
select {
case cc.receivedMessageReader.C() <- r:
case <-cc.Context().Done():
}
}