vendor/golang.org/x/crypto/ssh/connection.go

   1 // Copyright 2013 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package ssh
   6
   7 import (
   8         "fmt"
   9         "net"
  10 )
  11
  12 // OpenChannelError is returned if the other side rejects an
  13 // OpenChannel request.
  14 type OpenChannelError struct {
  15         Reason  RejectionReason
  16         Message string
  17 }
  18
  19 func (e *OpenChannelError) Error() string {
  20         return fmt.Sprintf("ssh: rejected: %s (%s)", e.Reason, e.Message)
  21 }
  22
  23 // ConnMetadata holds metadata for the connection.
  24 type ConnMetadata interface {
  25         // User returns the user ID for this connection.
  26         User() string
  27
  28         // SessionID returns the sesson hash, also denoted by H.
  29         SessionID() []byte
  30
  31         // ClientVersion returns the client's version string as hashed
  32         // into the session ID.
  33         ClientVersion() []byte
  34
  35         // ServerVersion returns the server's version string as hashed
  36         // into the session ID.
  37         ServerVersion() []byte
  38
  39         // RemoteAddr returns the remote address for this connection.
  40         RemoteAddr() net.Addr
  41
  42         // LocalAddr returns the local address for this connection.
  43         LocalAddr() net.Addr
  44 }
  45
  46 // Conn represents an SSH connection for both server and client roles.
  47 // Conn is the basis for implementing an application layer, such
  48 // as ClientConn, which implements the traditional shell access for
  49 // clients.
  50 type Conn interface {
  51         ConnMetadata
  52
  53         // SendRequest sends a global request, and returns the
  54         // reply. If wantReply is true, it returns the response status
  55         // and payload. See also RFC4254, section 4.
  56         SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error)
  57
  58         // OpenChannel tries to open an channel. If the request is
  59         // rejected, it returns *OpenChannelError. On success it returns
  60         // the SSH Channel and a Go channel for incoming, out-of-band
  61         // requests. The Go channel must be serviced, or the
  62         // connection will hang.
  63         OpenChannel(name string, data []byte) (Channel, <-chan *Request, error)
  64
  65         // Close closes the underlying network connection
  66         Close() error
  67
  68         // Wait blocks until the connection has shut down, and returns the
  69         // error causing the shutdown.
  70         Wait() error
  71
  72         // TODO(hanwen): consider exposing:
  73         //   RequestKeyChange
  74         //   Disconnect
  75 }
  76
  77 // DiscardRequests consumes and rejects all requests from the
  78 // passed-in channel.
  79 func DiscardRequests(in <-chan *Request) {
  80         for req := range in {
  81                 if req.WantReply {
  82                         req.Reply(false, nil)
  83                 }
  84         }
  85 }
  86
  87 // A connection represents an incoming connection.
  88 type connection struct {
  89         transport *handshakeTransport
  90         sshConn
  91
  92         // The connection protocol.
  93         *mux
  94 }
  95
  96 func (c *connection) Close() error {
  97         return c.sshConn.conn.Close()
  98 }
  99
 100 // sshconn provides net.Conn metadata, but disallows direct reads and
 101 // writes.
 102 type sshConn struct {
 103         conn net.Conn
 104
 105         user          string
 106         sessionID     []byte
 107         clientVersion []byte
 108         serverVersion []byte
 109 }
 110
 111 func dup(src []byte) []byte {
 112         dst := make([]byte, len(src))
 113         copy(dst, src)
 114         return dst
 115 }
 116
 117 func (c *sshConn) User() string {
 118         return c.user
 119 }
 120
 121 func (c *sshConn) RemoteAddr() net.Addr {
 122         return c.conn.RemoteAddr()
 123 }
 124
 125 func (c *sshConn) Close() error {
 126         return c.conn.Close()
 127 }
 128
 129 func (c *sshConn) LocalAddr() net.Addr {
 130         return c.conn.LocalAddr()
 131 }
 132
 133 func (c *sshConn) SessionID() []byte {
 134         return dup(c.sessionID)
 135 }
 136
 137 func (c *sshConn) ClientVersion() []byte {
 138         return dup(c.clientVersion)
 139 }
 140
 141 func (c *sshConn) ServerVersion() []byte {
 142         return dup(c.serverVersion)
 143 }