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mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
putty-source/sshchan.h
Simon Tatham aa08e6ca91 Put a layer of abstraction in front of struct ssh_channel.
Clients outside ssh.c - all implementations of Channel - will now not
see the ssh_channel data type itself, but only a subobject of the
interface type SshChannel. All the sshfwd_* functions have become
methods in that interface type's vtable (though, wrapped in the usual
kind of macros, the call sites look identical).

This paves the way for me to split up the SSH-1 and SSH-2 connection
layers and have each one lay out its channel bookkeeping structure as
it sees fit; as long as they each provide an implementation of the
sshfwd_ method family, the types behind that need not look different.

A minor good effect of this is that the sshfwd_ methods are no longer
global symbols, so they don't have to be stubbed in Unix Pageant to
get it to compile.
2018-09-19 23:08:27 +01:00

94 lines
3.7 KiB
C

/*
* Abstraction of the various ways to handle the local end of an SSH
* connection-layer channel.
*/
#ifndef PUTTY_SSHCHAN_H
#define PUTTY_SSHCHAN_H
struct ChannelVtable {
void (*free)(Channel *);
/* Called for channel types that were created at the same time as
* we sent an outgoing CHANNEL_OPEN, when the confirmation comes
* back from the server indicating that the channel has been
* opened, or the failure message indicating that it hasn't,
* respectively. In the latter case, this must _not_ free the
* Channel structure - the client will call the free method
* separately. But it might do logging or other local cleanup. */
void (*open_confirmation)(Channel *);
void (*open_failed)(Channel *, const char *error_text);
int (*send)(Channel *, int is_stderr, const void *buf, int len);
void (*send_eof)(Channel *);
void (*set_input_wanted)(Channel *, int wanted);
char *(*log_close_msg)(Channel *);
int (*want_close)(Channel *, int sent_local_eof, int rcvd_remote_eof);
};
struct Channel {
const struct ChannelVtable *vt;
unsigned initial_fixed_window_size;
};
#define chan_free(ch) ((ch)->vt->free(ch))
#define chan_open_confirmation(ch) ((ch)->vt->open_confirmation(ch))
#define chan_open_failed(ch, err) ((ch)->vt->open_failed(ch, err))
#define chan_send(ch, err, buf, len) ((ch)->vt->send(ch, err, buf, len))
#define chan_send_eof(ch) ((ch)->vt->send_eof(ch))
#define chan_set_input_wanted(ch, wanted) \
((ch)->vt->set_input_wanted(ch, wanted))
#define chan_log_close_msg(ch) ((ch)->vt->log_close_msg(ch))
#define chan_want_close(ch, leof, reof) ((ch)->vt->want_close(ch, leof, reof))
/*
* Reusable methods you can put in vtables to give default handling of
* some of those functions.
*/
/* open_confirmation / open_failed for any channel it doesn't apply to */
void chan_remotely_opened_confirmation(Channel *chan);
void chan_remotely_opened_failure(Channel *chan, const char *errtext);
/* want_close for any channel that wants the default behaviour of not
* closing until both directions have had an EOF */
int chan_no_eager_close(Channel *, int, int);
/* ----------------------------------------------------------------------
* This structure is owned by an SSH connection layer, and identifies
* the connection layer's end of the channel, for the Channel
* implementation to talk back to.
*/
struct SshChannelVtable {
int (*write)(SshChannel *c, const void *, int);
void (*write_eof)(SshChannel *c);
void (*unclean_close)(SshChannel *c, const char *err);
void (*unthrottle)(SshChannel *c, int bufsize);
Conf *(*get_conf)(SshChannel *c);
void (*window_override_removed)(SshChannel *c);
void (*x11_sharing_handover)(SshChannel *c,
ssh_sharing_connstate *share_cs,
share_channel *share_chan,
const char *peer_addr, int peer_port,
int endian, int protomajor, int protominor,
const void *initial_data, int initial_len);
};
struct SshChannel {
const struct SshChannelVtable *vt;
};
#define sshfwd_write(c, buf, len) ((c)->vt->write(c, buf, len))
#define sshfwd_write_eof(c) ((c)->vt->write_eof(c))
#define sshfwd_unclean_close(c, err) ((c)->vt->unclean_close(c, err))
#define sshfwd_unthrottle(c, bufsize) ((c)->vt->unthrottle(c, bufsize))
#define sshfwd_get_conf(c) ((c)->vt->get_conf(c))
#define sshfwd_window_override_removed(c) ((c)->vt->window_override_removed(c))
#define sshfwd_x11_sharing_handover(c, cs, ch, pa, pp, e, pmaj, pmin, d, l) \
((c)->vt->x11_sharing_handover(c, cs, ch, pa, pp, e, pmaj, pmin, d, l))
#endif /* PUTTY_SSHCHAN_H */