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package whatsapp
import (
"crypto/hmac"
"crypto/sha256"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"strings"
"github.com/Rhymen/go-whatsapp/binary"
"github.com/Rhymen/go-whatsapp/crypto/cbc"
"github.com/gorilla/websocket"
"github.com/pkg/errors"
)
func (wac *Conn) readPump() {
defer func() {
wac.wg.Done()
_, _ = wac.Disconnect()
}()
var readErr error
var msgType int
var reader io.Reader
for {
readerFound := make(chan struct{})
go func() {
if wac.ws != nil {
msgType, reader, readErr = wac.ws.conn.NextReader()
}
close(readerFound)
}()
select {
case <-readerFound:
if readErr != nil {
wac.handle(&ErrConnectionFailed{Err: readErr})
return
}
msg, err := ioutil.ReadAll(reader)
if err != nil {
wac.handle(errors.Wrap(err, "error reading message from Reader"))
continue
}
err = wac.processReadData(msgType, msg)
if err != nil {
wac.handle(errors.Wrap(err, "error processing data"))
}
case <-wac.ws.close:
return
}
}
}
func (wac *Conn) processReadData(msgType int, msg []byte) error {
data := strings.SplitN(string(msg), ",", 2)
if data[0][0] == '!' { //Keep-Alive Timestamp
data = append(data, data[0][1:]) //data[1]
data[0] = "!"
}
if len(data) == 2 && len(data[1]) == 0 {
return nil
}
if len(data) != 2 || len(data[1]) == 0 {
return ErrInvalidWsData
}
wac.listener.RLock()
listener, hasListener := wac.listener.m[data[0]]
wac.listener.RUnlock()
if hasListener {
// listener only exists for TextMessages query messages out of contact.go
// If these binary query messages can be handled another way,
// then the TextMessages, which are all JSON encoded, can directly
// be unmarshalled. The listener chan could then be changed from type
// chan string to something like chan map[string]interface{}. The unmarshalling
// in several places, especially in session.go, would then be gone.
listener <- data[1]
close(listener)
wac.removeListener(data[0])
} else if msgType == websocket.BinaryMessage {
wac.loginSessionLock.RLock()
sess := wac.session
wac.loginSessionLock.RUnlock()
if sess == nil || sess.MacKey == nil || sess.EncKey == nil {
return ErrInvalidWsState
}
message, err := wac.decryptBinaryMessage([]byte(data[1]))
if err != nil {
return errors.Wrap(err, "error decoding binary")
}
wac.dispatch(message)
} else { //RAW json status updates
wac.handle(string(data[1]))
}
return nil
}
func (wac *Conn) decryptBinaryMessage(msg []byte) (*binary.Node, error) {
//message validation
h2 := hmac.New(sha256.New, wac.session.MacKey)
if len(msg) < 33 {
var response struct {
Status int `json:"status"`
}
if err := json.Unmarshal(msg, &response); err == nil {
if response.Status == http.StatusNotFound {
return nil, ErrServerRespondedWith404
}
return nil, errors.New(fmt.Sprintf("server responded with %d", response.Status))
}
return nil, ErrInvalidServerResponse
}
h2.Write([]byte(msg[32:]))
if !hmac.Equal(h2.Sum(nil), msg[:32]) {
return nil, ErrInvalidHmac
}
// message decrypt
d, err := cbc.Decrypt(wac.session.EncKey, nil, msg[32:])
if err != nil {
return nil, errors.Wrap(err, "decrypting message with AES-CBC failed")
}
// message unmarshal
message, err := binary.Unmarshal(d)
if err != nil {
return nil, errors.Wrap(err, "could not decode binary")
}
return message, nil
}
|
