145 lines
2.9 KiB
Go
145 lines
2.9 KiB
Go
package aiakos
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import (
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"bytes"
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"errors"
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"fmt"
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"github.com/certusone/aiakos/commands"
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"github.com/certusone/aiakos/connector"
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"github.com/certusone/aiakos/securechannel"
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"math/rand"
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"sync"
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"time"
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)
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type (
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SessionManager struct {
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sessions []*securechannel.SecureChannel
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lock sync.Mutex
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connector connector.Connector
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authKeyID uint16
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password string
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poolSize uint
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creationWait sync.WaitGroup
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destroyed bool
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Connected chan bool
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}
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)
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var (
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echoPayload = []byte("keepalive")
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)
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func NewSessionManager(connector connector.Connector, authKeyID uint16, password string, poolSize uint) (*SessionManager, error) {
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if poolSize > 16 {
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return nil, errors.New("pool size exceeds session limit")
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}
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manager := &SessionManager{
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sessions: make([]*securechannel.SecureChannel, 0),
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connector: connector,
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authKeyID: authKeyID,
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password: password,
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poolSize: poolSize,
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destroyed: false,
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Connected: make(chan bool, 1),
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}
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manager.household()
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go func() {
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for {
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manager.household()
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time.Sleep(15 * time.Second)
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}
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}()
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return manager, nil
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}
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func (s *SessionManager) household() {
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func() {
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s.lock.Lock()
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defer s.lock.Unlock()
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for i, session := range s.sessions {
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// Send echo command
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command, _ := commands.CreateEchoCommand(echoPayload)
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resp, err := session.SendEncryptedCommand(command)
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if err == nil {
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parsedResp, matched := resp.(*commands.EchoResponse)
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if !matched {
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err = errors.New("invalid response type")
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}
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if !bytes.Equal(parsedResp.Data, echoPayload) {
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err = errors.New("echoed data is invalid")
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}
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}
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if session.Counter > securechannel.MaxMessagesPerSession*0.9 || err != nil {
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// Remove expired session
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go session.Close()
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copy(s.sessions[i:], s.sessions[i+1:])
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s.sessions[len(s.sessions)-1] = nil
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s.sessions = s.sessions[:len(s.sessions)-1]
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}
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}
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for i := 0; i < int(s.poolSize)-len(s.sessions); i++ {
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s.creationWait.Add(1)
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go func() {
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defer s.creationWait.Done()
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newSession, err := securechannel.NewSecureChannel(s.connector, s.authKeyID, s.password)
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if err != nil {
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fmt.Println(err.Error())
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return
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}
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err = newSession.Authenticate()
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if err != nil {
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fmt.Println(err)
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return
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}
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s.lock.Lock()
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defer s.lock.Unlock()
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s.sessions = append(s.sessions, newSession)
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select {
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case s.Connected <- true:
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default:
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}
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}()
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}
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}()
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s.creationWait.Wait()
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}
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func (s *SessionManager) GetSession() (*securechannel.SecureChannel, error) {
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if s.destroyed {
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return nil, errors.New("sessionmanager has already been destroyed")
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}
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if len(s.sessions) == 0 {
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return nil, errors.New("no sessions available")
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}
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s.lock.Lock()
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defer s.lock.Unlock()
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return s.sessions[rand.Intn(len(s.sessions))], nil
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}
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func (s *SessionManager) Destroy() {
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s.lock.Lock()
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defer s.lock.Unlock()
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for _, session := range s.sessions {
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session.Close()
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}
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s.destroyed = true
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}
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