ricochet-go/core/onionconnector.go

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package core
import (
"errors"
"golang.org/x/net/context"
"log"
"net"
"strings"
"time"
)
// XXX on failures, decide how long to wait before trying again
// XXX limit and queue global attempts?
// XXX circ/stream/fetch monitoring
type OnionConnector struct {
Network *Network
NeverGiveUp bool
AttemptCount int
}
// Attempt to connect to 'address', which must be a .onion address and port,
// using the Network from this OnionConnector instance.
//
// If NeverGiveUp is set, failed connections will be retried automatically,
// with appropriate backoff periods, and an error is only returned in fatal
// situations. The backoff is defined by AttemptCount on the OnionConnector
// instance -- it is not reset after Connect returns.
//
// If the Network is not ready, this function will wait and monitor the
// Network's status.
//
// Context can be used to set a timeout, deadline, or cancel function for
// the connection attempt.
func (oc *OnionConnector) Connect(address string, c context.Context) (net.Conn, error) {
if oc.Network == nil {
return nil, errors.New("No network configured for connector")
}
host, _, err := net.SplitHostPort(address)
if err != nil || !strings.HasSuffix(host, ".onion") {
return nil, errors.New("Invalid address")
}
options := &net.Dialer{
Cancel: c.Done(),
Timeout: 0, // XXX should use timeout
}
for {
// XXX This waits to know SOCKS info, but does not wait for connection
// ready state; should it?
proxy, err := oc.Network.WaitForProxyDialer(options, c)
if err != nil {
return nil, err
}
conn, err := proxy.Dial("tcp", address)
if err != nil {
if c.Err() != nil {
return nil, c.Err()
}
if !oc.NeverGiveUp {
return nil, err
}
log.Printf("Connection attempt to %s failed: %s", address, err)
if err := oc.Backoff(c); err != nil {
return nil, err
}
continue
}
return conn, nil
}
}
func (oc *OnionConnector) Backoff(c context.Context) error {
oc.AttemptCount++
// XXX This should actually do backoff and be less dumb
waitCtx, finish := context.WithTimeout(c, 10*time.Second)
defer finish()
<-waitCtx.Done()
return c.Err()
}