channel.h

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 #ifndef _CHANNEL_H_
  26 #define _CHANNEL_H_
  27
  28 #include "includes.h"
  29 #include "buffer.h"
  30 #include "circbuffer.h"
  31
  32 /* channel->type values */
  33 #define CHANNEL_ID_NONE 0
  34 #define CHANNEL_ID_SESSION 1
  35 #define CHANNEL_ID_X11 2
  36 #define CHANNEL_ID_AGENT 3
  37 #define CHANNEL_ID_TCPDIRECT 4
  38 #define CHANNEL_ID_TCPFORWARDED 5
  39
  40 #define SSH_OPEN_ADMINISTRATIVELY_PROHIBITED    1
  41 #define SSH_OPEN_CONNECT_FAILED                 2
  42 #define SSH_OPEN_UNKNOWN_CHANNEL_TYPE           3
  43 #define SSH_OPEN_RESOURCE_SHORTAGE              4
  44
  45 /* Not a real type */
  46 #define SSH_OPEN_IN_PROGRESS                                    99
  47
  48 #define CHAN_EXTEND_SIZE 3 /* how many extra slots to add when we need more */
  49
  50 struct ChanType;
  51
  52 struct Channel {
  53
  54         unsigned int index; /* the local channel index */
  55         unsigned int remotechan;
  56         unsigned int recvwindow, transwindow;
  57         unsigned int recvdonelen;
  58         unsigned int recvmaxpacket, transmaxpacket;
  59         void* typedata; /* a pointer to type specific data */
  60         int writefd; /* read from wire, written to insecure side */
  61         int readfd; /* read from insecure side, written to wire */
  62         int errfd; /* used like writefd or readfd, depending if it's client or server.
  63                                   Doesn't exactly belong here, but is cleaner here */
  64         circbuffer *writebuf; /* data from the wire, for local consumption */
  65         circbuffer *extrabuf; /* extended-data for the program - used like writebuf
  66                                              but for stderr */
  67
  68         /* whether close/eof messages have been exchanged */
  69         int sent_close, recv_close;
  70         int recv_eof, sent_eof;
  71
  72         int initconn; /* used for TCP forwarding, whether the channel has been
  73                                          fully initialised */
  74
  75         int await_open; /* flag indicating whether we've sent an open request
  76                                            for this channel (and are awaiting a confirmation
  77                                            or failure). */
  78
  79         int flushing;
  80
  81         const struct ChanType* type;
  82
  83 };
  84
  85 struct ChanType {
  86
  87         int sepfds; /* Whether this channel has seperate pipes for in/out or not */
  88         char *name;
  89         int (*inithandler)(struct Channel*);
  90         int (*check_close)(struct Channel*);
  91         void (*reqhandler)(struct Channel*);
  92         void (*closehandler)(struct Channel*);
  93
  94 };
  95
  96 void chaninitialise(const struct ChanType *chantypes[]);
  97 void chancleanup();
  98 void setchannelfds(fd_set *readfd, fd_set *writefd);
  99 void channelio(fd_set *readfd, fd_set *writefd);
 100 struct Channel* getchannel();
 101 struct Channel* newchannel(unsigned int remotechan,
 102                 const struct ChanType *type,
 103                 unsigned int transwindow, unsigned int transmaxpacket);
 104
 105 void recv_msg_channel_open();
 106 void recv_msg_channel_request();
 107 void send_msg_channel_failure(struct Channel *channel);
 108 void send_msg_channel_success(struct Channel *channel);
 109 void recv_msg_channel_data();
 110 void recv_msg_channel_extended_data();
 111 void recv_msg_channel_window_adjust();
 112 void recv_msg_channel_close();
 113 void recv_msg_channel_eof();
 114
 115 void common_recv_msg_channel_data(struct Channel *channel, int fd,
 116                 circbuffer * buf);
 117
 118 #ifdef DROPBEAR_CLIENT
 119 extern const struct ChanType clichansess;
 120 #endif
 121
 122 #if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT)
 123 int send_msg_channel_open_init(int fd, const struct ChanType *type);
 124 void recv_msg_channel_open_confirmation();
 125 void recv_msg_channel_open_failure();
 126 #endif
 127
 128 #endif /* _CHANNEL_H_ */