forked from gravitational/teleport
/
forward.go
72 lines (66 loc) · 2.13 KB
/
forward.go
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/*
* Teleport
* Copyright (C) 2023 Gravitational, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package sshutils
import (
"context"
"errors"
"github.com/gravitational/trace"
"golang.org/x/crypto/ssh"
)
// RequestForwarder represents a resource capable of sending
// an ssh request such as an ssh.Channel or ssh.Session.
type RequestForwarder interface {
SendRequest(ctx context.Context, name string, wantReply bool, payload []byte) (bool, error)
}
// ForwardRequest is a helper for forwarding a request across a session or channel.
func ForwardRequest(ctx context.Context, sender RequestForwarder, req *ssh.Request) (bool, error) {
reply, err := sender.SendRequest(ctx, req.Type, req.WantReply, req.Payload)
if err != nil || !req.WantReply {
return reply, trace.Wrap(err)
}
return reply, trace.Wrap(req.Reply(reply, nil))
}
// ForwardRequests forwards all ssh requests received from the
// given channel until the channel or context is closed.
func ForwardRequests(ctx context.Context, sin <-chan *ssh.Request, sender RequestForwarder) error {
for {
select {
case sreq, ok := <-sin:
if !ok {
// channel closed, stop processing
return nil
}
switch sreq.Type {
case WindowChangeRequest:
if _, err := ForwardRequest(ctx, sender, sreq); err != nil {
return trace.Wrap(err)
}
default:
if sreq.WantReply {
sreq.Reply(false, nil)
}
continue
}
case <-ctx.Done():
if !errors.Is(ctx.Err(), context.Canceled) {
return trace.Wrap(ctx.Err())
}
return nil
}
}
}