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conn.go
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conn.go
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package amqp
import (
"bytes"
"crypto/tls"
"errors"
"fmt"
"math"
"net"
"net/url"
"sync"
"time"
"github.com/pdaures/go-amqp/internal/bitmap"
"github.com/pdaures/go-amqp/internal/buffer"
"github.com/pdaures/go-amqp/internal/debug"
"github.com/pdaures/go-amqp/internal/encoding"
"github.com/pdaures/go-amqp/internal/frames"
"github.com/pdaures/go-amqp/internal/shared"
)
// Default connection options
const (
defaultIdleTimeout = 1 * time.Minute
defaultMaxFrameSize = 65536
defaultMaxSessions = 65536
)
// ConnOptions contains the optional settings for configuring an AMQP connection.
type ConnOptions struct {
// ContainerID sets the container-id to use when opening the connection.
//
// A container ID will be randomly generated if this option is not used.
ContainerID string
// HostName sets the hostname sent in the AMQP
// Open frame and TLS ServerName (if not otherwise set).
HostName string
// IdleTimeout specifies the maximum period in milliseconds between
// receiving frames from the peer.
//
// Specify a value less than zero to disable idle timeout.
//
// Default: 1 minute.
IdleTimeout time.Duration
// MaxFrameSize sets the maximum frame size that
// the connection will accept.
//
// Must be 512 or greater.
//
// Default: 512.
MaxFrameSize uint32
// MaxSessions sets the maximum number of channels.
// The value must be greater than zero.
//
// Default: 65535.
MaxSessions uint16
// Properties sets an entry in the connection properties map sent to the server.
Properties map[string]interface{}
// SASLType contains the specified SASL authentication mechanism.
SASLType SASLType
// Timeout configures how long to wait for the
// server during connection establishment.
//
// Once the connection has been established, IdleTimeout
// applies. If duration is zero, no timeout will be applied.
//
// Default: 0.
Timeout time.Duration
// TLSConfig sets the tls.Config to be used during
// TLS negotiation.
//
// This option is for advanced usage, in most scenarios
// providing a URL scheme of "amqps://" is sufficient.
TLSConfig *tls.Config
// test hook
dialer dialer
}
// used to abstract the underlying dialer for testing purposes
type dialer interface {
NetDialerDial(c *conn, host, port string) error
TLSDialWithDialer(c *conn, host, port string) error
}
// conn is an AMQP connection.
// only exported fields and methods are part of public surface area,
// all others are considered to be internal implementation details.
type conn struct {
net net.Conn // underlying connection
connectTimeout time.Duration // time to wait for reads/writes during conn establishment
dialer dialer // used for testing purposes, it allows faking dialing TCP/TLS endpoints
// TLS
tlsNegotiation bool // negotiate TLS
tlsComplete bool // TLS negotiation complete
tlsConfig *tls.Config // TLS config, default used if nil (ServerName set to Client.hostname)
// SASL
saslHandlers map[encoding.Symbol]stateFunc // map of supported handlers keyed by SASL mechanism, SASL not negotiated if nil
saslComplete bool // SASL negotiation complete; internal *except* for SASL auth methods
// local settings
maxFrameSize uint32 // max frame size to accept
channelMax uint16 // maximum number of channels to allow
hostname string // hostname of remote server (set explicitly or parsed from URL)
idleTimeout time.Duration // maximum period between receiving frames
properties map[encoding.Symbol]interface{} // additional properties sent upon connection open
containerID string // set explicitly or randomly generated
// peer settings
peerIdleTimeout time.Duration // maximum period between sending frames
PeerMaxFrameSize uint32 // maximum frame size peer will accept
// conn state
errMu sync.Mutex // mux holds errMu from start until shutdown completes; operations are sequential before mux is started
err error // error to be returned to client
Done chan struct{} // indicates the connection is done
// mux
connErr chan error // connReader/Writer notifications of an error
closeMux chan struct{} // indicates that the mux should stop
closeMuxOnce sync.Once
// session tracking
channels *bitmap.Bitmap
sessionsByChannel map[uint16]*Session
sessionsByChannelMu sync.RWMutex
// connReader
rxProto chan protoHeader // protoHeaders received by connReader
rxFrame chan frames.Frame // AMQP frames received by connReader
rxDone chan struct{}
connReaderRun chan func() // functions to be run by conn reader (set deadline on conn to run)
// connWriter
txFrame chan frames.Frame // AMQP frames to be sent by connWriter
txBuf buffer.Buffer // buffer for marshaling frames before transmitting
txDone chan struct{}
}
// implements the dialer interface
type defaultDialer struct{}
func (defaultDialer) NetDialerDial(c *conn, host, port string) (err error) {
dialer := &net.Dialer{Timeout: c.connectTimeout}
c.net, err = dialer.Dial("tcp", net.JoinHostPort(host, port))
return
}
func (defaultDialer) TLSDialWithDialer(c *conn, host, port string) (err error) {
dialer := &net.Dialer{Timeout: c.connectTimeout}
c.net, err = tls.DialWithDialer(dialer, "tcp", net.JoinHostPort(host, port), c.tlsConfig)
return
}
func dialConn(addr string, opts *ConnOptions) (*conn, error) {
u, err := url.Parse(addr)
if err != nil {
return nil, err
}
host, port := u.Hostname(), u.Port()
if port == "" {
port = "5672"
if u.Scheme == "amqps" || u.Scheme == "amqp+ssl" {
port = "5671"
}
}
var cp ConnOptions
if opts != nil {
cp = *opts
}
// prepend SASL credentials when the user/pass segment is not empty
if u.User != nil {
pass, _ := u.User.Password()
cp.SASLType = SASLTypePlain(u.User.Username(), pass)
}
if cp.HostName == "" {
cp.HostName = host
}
c, err := newConn(nil, &cp)
if err != nil {
return nil, err
}
switch u.Scheme {
case "amqp", "":
err = c.dialer.NetDialerDial(c, host, port)
case "amqps", "amqp+ssl":
c.initTLSConfig()
c.tlsNegotiation = false
err = c.dialer.TLSDialWithDialer(c, host, port)
default:
err = fmt.Errorf("unsupported scheme %q", u.Scheme)
}
if err != nil {
return nil, err
}
return c, nil
}
func newConn(netConn net.Conn, opts *ConnOptions) (*conn, error) {
c := &conn{
dialer: defaultDialer{},
net: netConn,
maxFrameSize: defaultMaxFrameSize,
PeerMaxFrameSize: defaultMaxFrameSize,
channelMax: defaultMaxSessions - 1, // -1 because channel-max starts at zero
idleTimeout: defaultIdleTimeout,
containerID: shared.RandString(40),
Done: make(chan struct{}),
connErr: make(chan error, 2), // buffered to ensure connReader/Writer won't leak
closeMux: make(chan struct{}),
rxProto: make(chan protoHeader),
rxFrame: make(chan frames.Frame),
rxDone: make(chan struct{}),
connReaderRun: make(chan func(), 1), // buffered to allow queueing function before interrupt
txFrame: make(chan frames.Frame),
txDone: make(chan struct{}),
sessionsByChannel: map[uint16]*Session{},
}
// apply options
if opts == nil {
opts = &ConnOptions{}
}
if opts.ContainerID != "" {
c.containerID = opts.ContainerID
}
if opts.HostName != "" {
c.hostname = opts.HostName
}
if opts.IdleTimeout > 0 {
c.idleTimeout = opts.IdleTimeout
} else if opts.IdleTimeout < 0 {
c.idleTimeout = 0
}
if opts.MaxFrameSize > 0 && opts.MaxFrameSize < 512 {
return nil, fmt.Errorf("invalid MaxFrameSize value %d", opts.MaxFrameSize)
} else if opts.MaxFrameSize > 512 {
c.maxFrameSize = opts.MaxFrameSize
}
if opts.MaxSessions > 0 {
c.channelMax = opts.MaxSessions
}
if opts.SASLType != nil {
if err := opts.SASLType(c); err != nil {
return nil, err
}
}
if opts.Timeout > 0 {
c.connectTimeout = opts.Timeout
}
if opts.Properties != nil {
c.properties = make(map[encoding.Symbol]interface{})
for key, val := range opts.Properties {
c.properties[encoding.Symbol(key)] = val
}
}
if opts.TLSConfig != nil {
c.tlsConfig = opts.TLSConfig.Clone()
}
if opts.dialer != nil {
c.dialer = opts.dialer
}
return c, nil
}
func (c *conn) initTLSConfig() {
// create a new config if not already set
if c.tlsConfig == nil {
c.tlsConfig = new(tls.Config)
}
// TLS config must have ServerName or InsecureSkipVerify set
if c.tlsConfig.ServerName == "" && !c.tlsConfig.InsecureSkipVerify {
c.tlsConfig.ServerName = c.hostname
}
}
// Start establishes the connection and begins multiplexing network IO.
// It is an error to call Start() on a connection that's been closed.
func (c *conn) Start() error {
// start reader
go c.connReader()
// run connection establishment state machine
for state := c.negotiateProto; state != nil; {
var err error
state, err = state()
// check if err occurred
if err != nil {
close(c.txDone) // close here since connWriter hasn't been started yet
_ = c.Close()
return err
}
}
// we can't create the channel bitmap until the connection has been established.
// this is because our peer can tell us the max channels they support.
c.channels = bitmap.New(uint32(c.channelMax))
// start multiplexor and writer
go c.mux()
go c.connWriter()
return nil
}
// Close closes the connection.
func (c *conn) Close() error {
c.closeMuxOnce.Do(func() { close(c.closeMux) })
err := c.Err()
var connErr *ConnectionError
if errors.As(err, &connErr) && connErr.inner == nil {
// an empty ConnectionError means the connection was closed by the caller
// or as requested by the peer and no error was provided in the close frame.
return nil
}
return err
}
// close should only be called by conn.mux.
func (c *conn) close() {
close(c.Done) // notify goroutines and blocked functions to exit
// wait for writing to stop, allows it to send the final close frame
<-c.txDone
// reading from connErr in mux can race with closeMux, causing
// a pending conn read/write error to be lost. now that the
// mux has exited, drain any pending error.
select {
case err := <-c.connErr:
c.err = err
default:
// no pending read/write error
}
err := c.net.Close()
switch {
// conn.err already set
// TODO: err info is lost, log it?
case c.err != nil:
// conn.err not set and c.net.Close() returned a non-nil error
case err != nil:
c.err = err
// no errors
default:
}
// check rxDone after closing net, otherwise may block
// for up to c.idleTimeout
<-c.rxDone
}
// Err returns the connection's error state after it's been closed.
// Calling this on an open connection will block until the connection is closed.
func (c *conn) Err() error {
c.errMu.Lock()
defer c.errMu.Unlock()
return &ConnectionError{inner: c.err}
}
func (c *conn) NewSession() (*Session, error) {
c.sessionsByChannelMu.Lock()
defer c.sessionsByChannelMu.Unlock()
// create the next session to allocate
// note that channel always start at 0
channel, ok := c.channels.Next()
if !ok {
return nil, fmt.Errorf("reached connection channel max (%d)", c.channelMax)
}
session := newSession(c, uint16(channel))
c.sessionsByChannel[session.channel] = session
return session, nil
}
func (c *conn) DeleteSession(s *Session) {
c.sessionsByChannelMu.Lock()
defer c.sessionsByChannelMu.Unlock()
delete(c.sessionsByChannel, s.channel)
c.channels.Remove(uint32(s.channel))
}
// mux is started in it's own goroutine after initial connection establishment.
// It handles muxing of sessions, keepalives, and connection errors.
func (c *conn) mux() {
var (
// map channels to sessions
sessionsByRemoteChannel = make(map[uint16]*Session)
)
// hold the errMu lock until error or done
c.errMu.Lock()
defer c.errMu.Unlock()
defer c.close() // defer order is important. c.errMu unlock indicates that connection is finally complete
for {
// check if last loop returned an error
if c.err != nil {
return
}
select {
// error from connReader
case c.err = <-c.connErr:
// new frame from connReader
case fr := <-c.rxFrame:
var (
session *Session
ok bool
)
switch body := fr.Body.(type) {
// Server initiated close.
case *frames.PerformClose:
if body.Error != nil {
c.err = body.Error
}
return
// RemoteChannel should be used when frame is Begin
case *frames.PerformBegin:
if body.RemoteChannel == nil {
// since we only support remotely-initiated sessions, this is an error
// TODO: it would be ideal to not have this kill the connection
c.err = fmt.Errorf("%T: nil RemoteChannel", fr.Body)
break
}
c.sessionsByChannelMu.RLock()
session, ok = c.sessionsByChannel[*body.RemoteChannel]
c.sessionsByChannelMu.RUnlock()
if !ok {
c.err = fmt.Errorf("unexpected remote channel number %d", *body.RemoteChannel)
break
}
session.remoteChannel = fr.Channel
sessionsByRemoteChannel[fr.Channel] = session
case *frames.PerformEnd:
session, ok = sessionsByRemoteChannel[fr.Channel]
if !ok {
c.err = fmt.Errorf("%T: didn't find channel %d in sessionsByRemoteChannel (PerformEnd)", fr.Body, fr.Channel)
break
}
// we MUST remove the remote channel from our map as soon as we receive
// the ack (i.e. before passing it on to the session mux) on the session
// ending since the numbers are recycled.
delete(sessionsByRemoteChannel, fr.Channel)
default:
// pass on performative to the correct session
session, ok = sessionsByRemoteChannel[fr.Channel]
if !ok {
c.err = fmt.Errorf("%T: didn't find channel %d in sessionsByRemoteChannel", fr.Body, fr.Channel)
}
}
if !ok {
continue
}
select {
case session.rx <- fr:
case <-c.closeMux:
return
}
// connection is complete
case <-c.closeMux:
return
}
}
}
// connReader reads from the net.Conn, decodes frames, and passes them
// up via the conn.rxFrame and conn.rxProto channels.
func (c *conn) connReader() {
defer close(c.rxDone)
buf := &buffer.Buffer{}
var (
negotiating = true // true during conn establishment, check for protoHeaders
currentHeader frames.Header // keep track of the current header, for frames split across multiple TCP packets
frameInProgress bool // true if in the middle of receiving data for currentHeader
)
for {
switch {
// Cheaply reuse free buffer space when fully read.
case buf.Len() == 0:
buf.Reset()
// Prevent excessive/unbounded growth by shifting data to beginning of buffer.
case int64(buf.Size()) > int64(c.maxFrameSize):
buf.Reclaim()
}
// need to read more if buf doesn't contain the complete frame
// or there's not enough in buf to parse the header
if frameInProgress || buf.Len() < frames.HeaderSize {
if c.idleTimeout > 0 {
_ = c.net.SetReadDeadline(time.Now().Add(c.idleTimeout))
}
err := buf.ReadFromOnce(c.net)
if err != nil {
debug.Log(1, "connReader error: %v", err)
select {
// check if error was due to close in progress
case <-c.Done:
return
// if there is a pending connReaderRun function, execute it
case f := <-c.connReaderRun:
f()
continue
// send error to mux and return
default:
c.connErr <- err
return
}
}
}
// read more if buf doesn't contain enough to parse the header
if buf.Len() < frames.HeaderSize {
continue
}
// during negotiation, check for proto frames
if negotiating && bytes.Equal(buf.Bytes()[:4], []byte{'A', 'M', 'Q', 'P'}) {
const protoHeaderSize = 8
buf, ok := buf.Next(protoHeaderSize)
if !ok {
c.connErr <- errors.New("invalid protoHeader")
return
}
_ = buf[7]
if !bytes.Equal(buf[:4], []byte{'A', 'M', 'Q', 'P'}) {
c.connErr <- fmt.Errorf("unexpected protocol %q", buf[:4])
return
}
p := protoHeader{
ProtoID: protoID(buf[4]),
Major: buf[5],
Minor: buf[6],
Revision: buf[7],
}
if p.Major != 1 || p.Minor != 0 || p.Revision != 0 {
c.connErr <- fmt.Errorf("unexpected protocol version %d.%d.%d", p.Major, p.Minor, p.Revision)
return
}
// negotiation is complete once an AMQP proto frame is received
if p.ProtoID == protoAMQP {
negotiating = false
}
// send proto header
select {
case <-c.Done:
return
case c.rxProto <- p:
}
continue
}
// parse the header if a frame isn't in progress
if !frameInProgress {
var err error
currentHeader, err = frames.ParseHeader(buf)
if err != nil {
c.connErr <- err
return
}
frameInProgress = true
}
// check size is reasonable
if currentHeader.Size > math.MaxInt32 { // make max size configurable
c.connErr <- errors.New("payload too large")
return
}
bodySize := int64(currentHeader.Size - frames.HeaderSize)
// the full frame has been received
if int64(buf.Len()) < bodySize {
continue
}
frameInProgress = false
// check if body is empty (keepalive)
if bodySize == 0 {
continue
}
// parse the frame
b, ok := buf.Next(bodySize)
if !ok {
c.connErr <- fmt.Errorf("buffer EOF; requested bytes: %d, actual size: %d", bodySize, buf.Len())
return
}
parsedBody, err := frames.ParseBody(buffer.New(b))
if err != nil {
c.connErr <- err
return
}
// send to mux
select {
case <-c.Done:
return
case c.rxFrame <- frames.Frame{Channel: currentHeader.Channel, Body: parsedBody}:
}
}
}
func (c *conn) connWriter() {
defer close(c.txDone)
// disable write timeout
if c.connectTimeout != 0 {
c.connectTimeout = 0
_ = c.net.SetWriteDeadline(time.Time{})
}
var (
// keepalives are sent at a rate of 1/2 idle timeout
keepaliveInterval = c.peerIdleTimeout / 2
// 0 disables keepalives
keepalivesEnabled = keepaliveInterval > 0
// set if enable, nil if not; nil channels block forever
keepalive <-chan time.Time
)
if keepalivesEnabled {
ticker := time.NewTicker(keepaliveInterval)
defer ticker.Stop()
keepalive = ticker.C
}
var err error
for {
if err != nil {
debug.Log(1, "connWriter error: %v", err)
c.connErr <- err
return
}
select {
// frame write request
case fr := <-c.txFrame:
err = c.writeFrame(fr)
if err == nil && fr.Done != nil {
close(fr.Done)
}
// keepalive timer
case <-keepalive:
debug.Log(3, "sending keep-alive frame")
_, err = c.net.Write(keepaliveFrame)
// It would be slightly more efficient in terms of network
// resources to reset the timer each time a frame is sent.
// However, keepalives are small (8 bytes) and the interval
// is usually on the order of minutes. It does not seem
// worth it to add extra operations in the write path to
// avoid. (To properly reset a timer it needs to be stopped,
// possibly drained, then reset.)
// connection complete
case <-c.Done:
// send close
cls := &frames.PerformClose{}
debug.Log(1, "TX (connWriter): %s", cls)
_ = c.writeFrame(frames.Frame{
Type: frames.TypeAMQP,
Body: cls,
})
return
}
}
}
// writeFrame writes a frame to the network.
// used externally by SASL only.
func (c *conn) writeFrame(fr frames.Frame) error {
if c.connectTimeout != 0 {
_ = c.net.SetWriteDeadline(time.Now().Add(c.connectTimeout))
}
// writeFrame into txBuf
c.txBuf.Reset()
err := frames.Write(&c.txBuf, fr)
if err != nil {
return err
}
// validate the frame isn't exceeding peer's max frame size
requiredFrameSize := c.txBuf.Len()
if uint64(requiredFrameSize) > uint64(c.PeerMaxFrameSize) {
return fmt.Errorf("%T frame size %d larger than peer's max frame size %d", fr, requiredFrameSize, c.PeerMaxFrameSize)
}
// write to network
_, err = c.net.Write(c.txBuf.Bytes())
return err
}
// writeProtoHeader writes an AMQP protocol header to the
// network
func (c *conn) writeProtoHeader(pID protoID) error {
if c.connectTimeout != 0 {
_ = c.net.SetWriteDeadline(time.Now().Add(c.connectTimeout))
}
_, err := c.net.Write([]byte{'A', 'M', 'Q', 'P', byte(pID), 1, 0, 0})
return err
}
// keepaliveFrame is an AMQP frame with no body, used for keepalives
var keepaliveFrame = []byte{0x00, 0x00, 0x00, 0x08, 0x02, 0x00, 0x00, 0x00}
// SendFrame is used by sessions and links to send frames across the network.
func (c *conn) SendFrame(fr frames.Frame) error {
select {
case c.txFrame <- fr:
return nil
case <-c.Done:
return c.Err()
}
}
// stateFunc is a state in a state machine.
//
// The state is advanced by returning the next state.
// The state machine concludes when nil is returned.
type stateFunc func() (stateFunc, error)
// negotiateProto determines which proto to negotiate next.
// used externally by SASL only.
func (c *conn) negotiateProto() (stateFunc, error) {
// in the order each must be negotiated
switch {
case c.tlsNegotiation && !c.tlsComplete:
return c.exchangeProtoHeader(protoTLS)
case c.saslHandlers != nil && !c.saslComplete:
return c.exchangeProtoHeader(protoSASL)
default:
return c.exchangeProtoHeader(protoAMQP)
}
}
type protoID uint8
// protocol IDs received in protoHeaders
const (
protoAMQP protoID = 0x0
protoTLS protoID = 0x2
protoSASL protoID = 0x3
)
// exchangeProtoHeader performs the round trip exchange of protocol
// headers, validation, and returns the protoID specific next state.
func (c *conn) exchangeProtoHeader(pID protoID) (stateFunc, error) {
// write the proto header
if err := c.writeProtoHeader(pID); err != nil {
return nil, err
}
// read response header
p, err := c.readProtoHeader()
if err != nil {
return nil, err
}
if pID != p.ProtoID {
return nil, fmt.Errorf("unexpected protocol header %#00x, expected %#00x", p.ProtoID, pID)
}
// go to the proto specific state
switch pID {
case protoAMQP:
return c.openAMQP, nil
case protoTLS:
return c.startTLS, nil
case protoSASL:
return c.negotiateSASL, nil
default:
return nil, fmt.Errorf("unknown protocol ID %#02x", p.ProtoID)
}
}
// readProtoHeader reads a protocol header packet from c.rxProto.
func (c *conn) readProtoHeader() (protoHeader, error) {
var deadline <-chan time.Time
if c.connectTimeout != 0 {
deadline = time.After(c.connectTimeout)
}
var p protoHeader
select {
case p = <-c.rxProto:
return p, nil
case err := <-c.connErr:
return p, err
case fr := <-c.rxFrame:
return p, fmt.Errorf("readProtoHeader: unexpected frame %#v", fr)
case <-deadline:
return p, errors.New("amqp: timeout waiting for response")
}
}
// startTLS wraps the conn with TLS and returns to Client.negotiateProto
func (c *conn) startTLS() (stateFunc, error) {
c.initTLSConfig()
// buffered so connReaderRun won't block
done := make(chan error, 1)
// this function will be executed by connReader
c.connReaderRun <- func() {
defer close(done)
_ = c.net.SetReadDeadline(time.Time{}) // clear timeout
// wrap existing net.Conn and perform TLS handshake
tlsConn := tls.Client(c.net, c.tlsConfig)
if c.connectTimeout != 0 {
_ = tlsConn.SetWriteDeadline(time.Now().Add(c.connectTimeout))
}
done <- tlsConn.Handshake()
// TODO: return?
// swap net.Conn
c.net = tlsConn
c.tlsComplete = true
}
// set deadline to interrupt connReader
_ = c.net.SetReadDeadline(time.Time{}.Add(1))
if err := <-done; err != nil {
return nil, err
}
// go to next protocol
return c.negotiateProto, nil
}
// openAMQP round trips the AMQP open performative
func (c *conn) openAMQP() (stateFunc, error) {
// send open frame
open := &frames.PerformOpen{
ContainerID: c.containerID,
Hostname: c.hostname,
MaxFrameSize: c.maxFrameSize,
ChannelMax: c.channelMax,
IdleTimeout: c.idleTimeout / 2, // per spec, advertise half our idle timeout
Properties: c.properties,
}
debug.Log(1, "TX (openAMQP): %s", open)
err := c.writeFrame(frames.Frame{
Type: frames.TypeAMQP,
Body: open,
Channel: 0,
})
if err != nil {
return nil, err
}
// get the response
fr, err := c.readFrame()
if err != nil {
return nil, err
}
o, ok := fr.Body.(*frames.PerformOpen)
if !ok {
return nil, fmt.Errorf("openAMQP: unexpected frame type %T", fr.Body)
}
debug.Log(1, "RX (openAMQP): %s", o)
// update peer settings
if o.MaxFrameSize > 0 {
c.PeerMaxFrameSize = o.MaxFrameSize
}
if o.IdleTimeout > 0 {
// TODO: reject very small idle timeouts
c.peerIdleTimeout = o.IdleTimeout
}
if o.ChannelMax < c.channelMax {
c.channelMax = o.ChannelMax
}
// connection established, exit state machine
return nil, nil
}
// negotiateSASL returns the SASL handler for the first matched
// mechanism specified by the server
func (c *conn) negotiateSASL() (stateFunc, error) {
// read mechanisms frame
fr, err := c.readFrame()
if err != nil {
return nil, err
}
sm, ok := fr.Body.(*frames.SASLMechanisms)
if !ok {
return nil, fmt.Errorf("negotiateSASL: unexpected frame type %T", fr.Body)
}
debug.Log(1, "RX (negotiateSASL): %s", sm)
// return first match in c.saslHandlers based on order received
for _, mech := range sm.Mechanisms {
if state, ok := c.saslHandlers[mech]; ok {
return state, nil
}
}
// no match
return nil, fmt.Errorf("no supported auth mechanism (%v)", sm.Mechanisms) // TODO: send "auth not supported" frame?
}
// saslOutcome processes the SASL outcome frame and return Client.negotiateProto
// on success.
//
// SASL handlers return this stateFunc when the mechanism specific negotiation
// has completed.
// used externally by SASL only.
func (c *conn) saslOutcome() (stateFunc, error) {
// read outcome frame
fr, err := c.readFrame()
if err != nil {
return nil, err
}
so, ok := fr.Body.(*frames.SASLOutcome)
if !ok {
return nil, fmt.Errorf("saslOutcome: unexpected frame type %T", fr.Body)
}
debug.Log(1, "RX (saslOutcome): %s", so)
// check if auth succeeded
if so.Code != encoding.CodeSASLOK {
return nil, fmt.Errorf("SASL PLAIN auth failed with code %#00x: %s", so.Code, so.AdditionalData) // implement Stringer for so.Code
}
// return to c.negotiateProto
c.saslComplete = true
return c.negotiateProto, nil
}
// readFrame is used during connection establishment to read a single frame.
//
// After setup, conn.mux handles incoming frames.
// used externally by SASL only.
func (c *conn) readFrame() (frames.Frame, error) {
var deadline <-chan time.Time
if c.connectTimeout != 0 {
deadline = time.After(c.connectTimeout)
}
var fr frames.Frame
select {
case fr = <-c.rxFrame:
return fr, nil
case err := <-c.connErr:
return fr, err
case p := <-c.rxProto:
return fr, fmt.Errorf("unexpected protocol header %#v", p)
case <-deadline:
return fr, errors.New("amqp: timeout waiting for response")
}
}