route/lib/tunnel/control.go

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2017-01-20 01:27:14 +00:00
package tunnel
import (
"encoding/json"
"errors"
"net"
"sync"
)
var errControlClosed = errors.New("control connection is closed")
type control struct {
// enc and dec are responsible for encoding and decoding json values forth
// and back
enc *json.Encoder
dec *json.Decoder
// underlying connection responsible for encoder and decoder
nc net.Conn
// identifier associated with this control
identifier string
mu sync.Mutex // guards the following
closed bool // if Close() and quits
}
func newControl(nc net.Conn) *control {
c := &control{
enc: json.NewEncoder(nc),
dec: json.NewDecoder(nc),
nc: nc,
}
return c
}
func (c *control) send(v interface{}) error {
if c.enc == nil {
return errors.New("encoder is not initialized")
}
c.mu.Lock()
if c.closed {
c.mu.Unlock()
return errControlClosed
}
c.mu.Unlock()
return c.enc.Encode(v)
}
func (c *control) recv(v interface{}) error {
if c.dec == nil {
return errors.New("decoder is not initialized")
}
c.mu.Lock()
if c.closed {
c.mu.Unlock()
return errControlClosed
}
c.mu.Unlock()
return c.dec.Decode(v)
}
func (c *control) Close() error {
if c.nc == nil {
return nil
}
c.mu.Lock()
c.closed = true
c.mu.Unlock()
return c.nc.Close()
}
type controls struct {
sync.Mutex
controls map[string]*control
}
func newControls() *controls {
return &controls{
controls: make(map[string]*control),
}
}
func (c *controls) getControl(identifier string) (*control, bool) {
c.Lock()
control, ok := c.controls[identifier]
c.Unlock()
return control, ok
}
func (c *controls) addControl(identifier string, control *control) {
control.identifier = identifier
c.Lock()
c.controls[identifier] = control
c.Unlock()
}
func (c *controls) deleteControl(identifier string) {
c.Lock()
delete(c.controls, identifier)
c.Unlock()
}