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/* channel_forward.h
*
* General channel type for forwarding data to an fd
*
*/
/* lsh, an implementation of the ssh protocol
*
* Copyright (C) 1998, 2001 Balzs Scheidler, Niels Mller
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include <errno.h>
#include <string.h>
#include "channel_forward.h"
#include "io.h"
#include "ssh.h"
#include "werror.h"
#include "xalloc.h"
#define GABA_DEFINE
#include "channel_forward.h.x"
#undef GABA_DEFINE
/* NOTE: Adds the socket to the channel's resource list */
void
init_channel_forward(struct channel_forward *self,
struct lsh_fd *socket, uint32_t initial_window)
{
assert(socket);
init_channel(&self->super);
/* The rest of the callbacks are not set up until
* channel_forward_start_io. */
/* NOTE: We don't need a close handler, as the channel's resource
* list is taken care of automatically. */
self->super.rec_window_size = initial_window;
/* FIXME: Make maximum packet size configurable. */
self->super.rec_max_packet = SSH_MAX_PACKET;
self->socket = socket;
remember_resource(self->super.resources, &socket->super);
}
struct channel_forward *
make_channel_forward(struct lsh_fd *socket, uint32_t initial_window)
{
NEW(channel_forward, self);
init_channel_forward(self, socket, initial_window);
return self;
}
static void
do_channel_forward_receive(struct ssh_channel *c,
int type, struct lsh_string *data)
{
CAST_SUBTYPE(channel_forward, closure, c);
switch (type)
{
case CHANNEL_DATA:
A_WRITE(&closure->socket->write_buffer->super, data);
break;
case CHANNEL_STDERR_DATA:
werror("Ignoring unexpected stderr data.\n");
lsh_string_free(data);
break;
default:
fatal("Internal error. do_channel_forward_receive");
}
}
static void
do_channel_forward_send_adjust(struct ssh_channel *s,
uint32_t i UNUSED)
{
CAST_SUBTYPE(channel_forward, self, s);
lsh_oop_register_read_fd(self->socket);
}
static void
do_channel_forward_eof(struct ssh_channel *s)
{
CAST_SUBTYPE(channel_forward, self, s);
/* We won't write any more. io.c should make sure that shutdown is called
* once the write_buffer is empty. */
close_fd_write(self->socket);
}
/* NOTE: Because this function is called by
* do_open_forwarded_tcpip_continuation, the same restrictions apply.
* I.e we can not assume that the channel is completely initialized
* (channel_open_continuation has not yet done its work), and we can't
* send any packets. */
void
channel_forward_start_io(struct channel_forward *channel)
{
channel->super.receive = do_channel_forward_receive;
channel->super.send_adjust = do_channel_forward_send_adjust;
channel->super.eof = do_channel_forward_eof;
/* Install callbacks on the local socket.
* NOTE: We don't install any channel_io_exception_handler. */
io_read_write(channel->socket,
make_channel_read_data(&channel->super),
/* FIXME: Make this configurable */
SSH_MAX_PACKET * 10, /* self->block_size, */
make_channel_read_close_callback(&channel->super));
/* Flow control */
channel->socket->write_buffer->report = &channel->super.super;
}
/* Like above, but doesn't install a new write buffer. Used by the socks server. */
void
channel_forward_start_io_read(struct channel_forward *channel)
{
channel->super.receive = do_channel_forward_receive;
channel->super.send_adjust = do_channel_forward_send_adjust;
channel->super.eof = do_channel_forward_eof;
/* Install callbacks on the local socket. Leave write callbacks alone */
io_read(channel->socket,
make_channel_read_data(&channel->super),
make_channel_read_close_callback(&channel->super));
/* Flow control */
channel->socket->write_buffer->report = &channel->super.super;
}
/* Used by the party requesting tcp forwarding, i.e. when a socket is
* already open, and we have asked the other end to forward it. Takes
* a channel as argument, and connects it to the socket. Returns the
* channel. */
DEFINE_COMMAND(start_io_command)
(struct command *s UNUSED,
struct lsh_object *x,
struct command_continuation *c,
struct exception_handler *e UNUSED)
{
CAST_SUBTYPE(channel_forward, channel, x);
assert(channel);
channel_forward_start_io(channel);
COMMAND_RETURN(c, channel);
}
/* FIXME: Arrange so that the forwarded socket is closed if
EXC_CHANNEL_OPEN is caught. And write some docs. */
static const struct report_exception_info forward_open_report =
STATIC_REPORT_EXCEPTION_INFO(EXC_ALL, EXC_CHANNEL_OPEN,
"Forwarding failed, could not open channel");
struct catch_report_collect catch_channel_open
= STATIC_CATCH_REPORT(&forward_open_report);
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