ricochet-go/vendor/github.com/s-rah/go-ricochet/ricochet.go

159 lines
4.0 KiB
Go

package goricochet
import (
"errors"
"github.com/s-rah/go-ricochet/utils"
"io"
"net"
"sync"
)
// Connect sets up a client ricochet connection to host e.g. qn6uo4cmsrfv4kzq.onion. If this
// function finished successfully then the connection can be assumed to
// be open and authenticated.
// To specify a local port using the format "127.0.0.1:[port]|ricochet-id".
func Connect(host string) (*OpenConnection, error) {
networkResolver := utils.NetworkResolver{}
conn, host, err := networkResolver.Resolve(host)
if err != nil {
return nil, err
}
return Open(conn, host)
}
// Open establishes a protocol session on an established net.Conn, and returns a new
// OpenConnection instance representing this connection. On error, the connection
// will be closed. This function blocks until version negotiation has completed.
// The application should call Process() on the returned OpenConnection to continue
// handling protocol messages.
func Open(conn net.Conn, remoteHostname string) (*OpenConnection, error) {
oc, err := negotiateVersion(conn, true)
if err != nil {
conn.Close()
return nil, err
}
oc.OtherHostname = remoteHostname
return oc, nil
}
// Serve accepts incoming connections on a net.Listener, negotiates protocol,
// and calls methods of the ServiceHandler to handle inbound connections. All
// calls to ServiceHandler happen on the caller's goroutine. The listener can
// be closed at any time to close the service.
func Serve(ln net.Listener, handler ServiceHandler) error {
defer ln.Close()
connChannel := make(chan interface{})
listenErrorChannel := make(chan error)
go func() {
var pending sync.WaitGroup
for {
conn, err := ln.Accept()
if err != nil {
// Wait for pending connections before returning an error; this
// prevents abandoned goroutines when the outer loop stops reading
// from connChannel.
pending.Wait()
listenErrorChannel <- err
close(connChannel)
return
}
pending.Add(1)
go func() {
defer pending.Done()
oc, err := negotiateVersion(conn, false)
if err != nil {
conn.Close()
connChannel <- err
} else {
connChannel <- oc
}
}()
}
}()
var listenErr error
for {
select {
case err := <-listenErrorChannel:
// Remember error, wait for connChannel to close
listenErr = err
case result, ok := <-connChannel:
if !ok {
return listenErr
}
switch v := result.(type) {
case *OpenConnection:
handler.OnNewConnection(v)
case error:
handler.OnFailedConnection(v)
}
}
}
return nil
}
// Perform version negotiation on the connection, and create an OpenConnection if successful
func negotiateVersion(conn net.Conn, outbound bool) (*OpenConnection, error) {
versions := []byte{0x49, 0x4D, 0x01, 0x01}
// Outbound side of the connection sends a list of supported versions
if outbound {
if n, err := conn.Write(versions); err != nil || n < len(versions) {
return nil, err
}
res := make([]byte, 1)
if _, err := io.ReadAtLeast(conn, res, len(res)); err != nil {
return nil, err
}
if res[0] != 0x01 {
return nil, errors.New("unsupported protocol version")
}
} else {
// Read version response header
header := make([]byte, 3)
if _, err := io.ReadAtLeast(conn, header, len(header)); err != nil {
return nil, err
}
if header[0] != versions[0] || header[1] != versions[1] || header[2] < 1 {
return nil, errors.New("invalid protocol response")
}
// Read list of supported versions (which is header[2] bytes long)
versionList := make([]byte, header[2])
if _, err := io.ReadAtLeast(conn, versionList, len(versionList)); err != nil {
return nil, err
}
selectedVersion := byte(0xff)
for _, v := range versionList {
if v == 0x01 {
selectedVersion = v
break
}
}
if n, err := conn.Write([]byte{selectedVersion}); err != nil || n < 1 {
return nil, err
}
if selectedVersion == 0xff {
return nil, errors.New("no supported protocol version")
}
}
oc := new(OpenConnection)
oc.Init(outbound, conn)
return oc, nil
}