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connector.go
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connector.go
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package connector
import (
"context"
"errors"
"fmt"
"net/url"
"sync"
"time"
"github.com/gorilla/websocket"
"github.com/smartcontractkit/chainlink/v2/core/logger"
"github.com/smartcontractkit/chainlink/v2/core/services/gateway/api"
"github.com/smartcontractkit/chainlink/v2/core/services/gateway/network"
"github.com/smartcontractkit/chainlink/v2/core/services/job"
"github.com/smartcontractkit/chainlink/v2/core/utils"
)
//go:generate mockery --quiet --name GatewayConnector --output ./mocks/ --case=underscore
//go:generate mockery --quiet --name Signer --output ./mocks/ --case=underscore
//go:generate mockery --quiet --name GatewayConnectorHandler --output ./mocks/ --case=underscore
// GatewayConnector is a component run by Nodes to connect to a set of Gateways.
type GatewayConnector interface {
job.ServiceCtx
network.ConnectionInitiator
SendToGateway(ctx context.Context, gatewayId string, msg *api.Message) error
}
// Signer implementation needs to be provided by a GatewayConnector user (node)
// in order to sign handshake messages with node's private key.
type Signer interface {
// Sign keccak256 hash of data.
Sign(data ...[]byte) ([]byte, error)
}
// GatewayConnector user (node) implements application logic in the Handler interface.
type GatewayConnectorHandler interface {
job.ServiceCtx
HandleGatewayMessage(ctx context.Context, gatewayId string, msg *api.Message)
}
type gatewayConnector struct {
utils.StartStopOnce
config *ConnectorConfig
codec api.Codec
clock utils.Clock
nodeAddress []byte
signer Signer
handler GatewayConnectorHandler
gateways map[string]*gatewayState
urlToId map[string]string
closeWait sync.WaitGroup
shutdownCh chan struct{}
lggr logger.Logger
}
type gatewayState struct {
conn network.WSConnectionWrapper
config ConnectorGatewayConfig
url *url.URL
wsClient network.WebSocketClient
}
func NewGatewayConnector(config *ConnectorConfig, signer Signer, handler GatewayConnectorHandler, clock utils.Clock, lggr logger.Logger) (GatewayConnector, error) {
if signer == nil || handler == nil || clock == nil {
return nil, errors.New("nil dependency")
}
if len(config.DonId) == 0 || len(config.DonId) > int(network.HandshakeDonIdLen) {
return nil, errors.New("invalid DON ID")
}
addressBytes, err := utils.TryParseHex(config.NodeAddress)
if err != nil {
return nil, err
}
connector := &gatewayConnector{
config: config,
codec: &api.JsonRPCCodec{},
clock: clock,
nodeAddress: addressBytes,
signer: signer,
handler: handler,
shutdownCh: make(chan struct{}),
lggr: lggr,
}
gateways := make(map[string]*gatewayState)
urlToId := make(map[string]string)
for _, gw := range config.Gateways {
gw := gw
if _, exists := gateways[gw.Id]; exists {
return nil, fmt.Errorf("duplicate Gateway ID %s", gw.Id)
}
if _, exists := urlToId[gw.URL]; exists {
return nil, fmt.Errorf("duplicate Gateway URL %s", gw.URL)
}
parsedURL, err := url.Parse(gw.URL)
if err != nil {
return nil, err
}
gateway := &gatewayState{
conn: network.NewWSConnectionWrapper(),
config: gw,
url: parsedURL,
wsClient: network.NewWebSocketClient(config.WsClientConfig, connector, lggr),
}
gateways[gw.Id] = gateway
urlToId[gw.URL] = gw.Id
}
connector.gateways = gateways
connector.urlToId = urlToId
return connector, nil
}
func (c *gatewayConnector) SendToGateway(ctx context.Context, gatewayId string, msg *api.Message) error {
data, err := c.codec.EncodeResponse(msg)
if err != nil {
return fmt.Errorf("error encoding response for gateway %s: %v", gatewayId, err)
}
gateway, ok := c.gateways[gatewayId]
if !ok {
return fmt.Errorf("invalid Gateway ID %s", gatewayId)
}
if gateway.conn == nil {
return fmt.Errorf("connector not started")
}
return gateway.conn.Write(ctx, websocket.BinaryMessage, data)
}
func (c *gatewayConnector) readLoop(gatewayState *gatewayState) {
ctx, cancel := utils.StopChan(c.shutdownCh).NewCtx()
defer cancel()
for {
select {
case <-c.shutdownCh:
c.closeWait.Done()
return
case item := <-gatewayState.conn.ReadChannel():
msg, err := c.codec.DecodeRequest(item.Data)
if err != nil {
c.lggr.Errorw("parse error when reading from Gateway", "id", gatewayState.config.Id, "err", err)
break
}
if err = msg.Validate(); err != nil {
c.lggr.Errorw("failed to validate message signature", "id", gatewayState.config.Id, "error", err)
break
}
c.handler.HandleGatewayMessage(ctx, gatewayState.config.Id, msg)
}
}
}
func (c *gatewayConnector) reconnectLoop(gatewayState *gatewayState) {
redialBackoff := utils.NewRedialBackoff()
ctx, cancel := utils.StopChan(c.shutdownCh).NewCtx()
defer cancel()
for {
conn, err := gatewayState.wsClient.Connect(ctx, gatewayState.url)
if err != nil {
c.lggr.Errorw("connection error", "url", gatewayState.url, "error", err)
} else {
c.lggr.Infow("connected successfully", "url", gatewayState.url)
closeCh := gatewayState.conn.Reset(conn)
<-closeCh
c.lggr.Infow("connection closed", "url", gatewayState.url)
// reset backoff
redialBackoff = utils.NewRedialBackoff()
}
select {
case <-c.shutdownCh:
c.closeWait.Done()
return
case <-time.After(redialBackoff.Duration()):
c.lggr.Info("reconnecting ...")
}
}
}
func (c *gatewayConnector) Start(ctx context.Context) error {
return c.StartOnce("GatewayConnector", func() error {
c.lggr.Info("starting gateway connector")
if err := c.handler.Start(ctx); err != nil {
return err
}
for _, gatewayState := range c.gateways {
gatewayState := gatewayState
if err := gatewayState.conn.Start(); err != nil {
return err
}
c.closeWait.Add(2)
go c.readLoop(gatewayState)
go c.reconnectLoop(gatewayState)
}
return nil
})
}
func (c *gatewayConnector) Close() error {
return c.StopOnce("GatewayConnector", func() (err error) {
c.lggr.Info("closing gateway connector")
close(c.shutdownCh)
for _, gatewayState := range c.gateways {
gatewayState.conn.Close()
}
c.closeWait.Wait()
return c.handler.Close()
})
}
func (c *gatewayConnector) NewAuthHeader(url *url.URL) ([]byte, error) {
gatewayId, found := c.urlToId[url.String()]
if !found {
return nil, network.ErrAuthInvalidGateway
}
authHeaderElems := &network.AuthHeaderElems{
Timestamp: uint32(c.clock.Now().Unix()),
DonId: c.config.DonId,
GatewayId: gatewayId,
}
packedElems := network.PackAuthHeader(authHeaderElems)
signature, err := c.signer.Sign(packedElems)
if err != nil {
return nil, err
}
return append(packedElems, signature...), nil
}
func (c *gatewayConnector) ChallengeResponse(url *url.URL, challenge []byte) ([]byte, error) {
challengeElems, err := network.UnpackChallenge(challenge)
if err != nil {
return nil, err
}
if len(challengeElems.ChallengeBytes) < c.config.AuthMinChallengeLen {
return nil, network.ErrChallengeTooShort
}
gatewayId, found := c.urlToId[url.String()]
if !found || challengeElems.GatewayId != gatewayId {
return nil, network.ErrAuthInvalidGateway
}
nowTs := uint32(c.clock.Now().Unix())
ts := challengeElems.Timestamp
if ts < nowTs-c.config.AuthTimestampToleranceSec || nowTs+c.config.AuthTimestampToleranceSec < ts {
return nil, network.ErrAuthInvalidTimestamp
}
return c.signer.Sign(challenge)
}