/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* This file contains functions for generic socket connection forwarding.
* There is also code for initiating connection forwarding for X11 connections,
* arbitrary tcp/ip connections, and the authentication agent connection.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* SSH2 support added by Markus Friedl.
* Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
* Copyright (c) 1999 Dug Song. All rights reserved.
* Copyright (c) 1999 Theo de Raadt. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
RCSID("$OpenBSD: channel.c,v 1.2 2001/05/30 15:20:09 markus Exp $");
#include "ssh2.h"
#include "packet.h"
#include "xmalloc.h"
#include "log.h"
#include "misc.h"
#include "channel.h"
#include "compat.h"
/*
* Pointer to an array containing all allocated channels. The array is
* dynamically extended as needed.
*/
Channel **channels = NULL;
/*
* Size of the channel array. All slots of the array must always be
* initialized (at least the type field); unused slots set to NULL
*/
int channels_alloc = 0;
/*
* Maximum file descriptor value used in any of the channels. This is
* updated in channel_new.
*/
int channel_max_fd = 0;
Channel *
channel_lookup(int id)
{
Channel *c;
if (id < 0 || id > channels_alloc) {
log("channel_lookup: %d: bad id", id);
return NULL;
}
c = channels[id];
if (c == NULL) {
log("channel_lookup: %d: bad id: channel free", id);
return NULL;
}
return c;
}
/*
* Register filedescriptors for a channel, used when allocating a channel or
* when the channel consumer/producer is ready, e.g. shell exec'd
*/
void
channel_register_fds(Channel *c, int rfd, int wfd, int efd,
int extusage, int nonblock)
{
/* Update the maximum file descriptor value. */
channel_max_fd = MAX(channel_max_fd, rfd);
channel_max_fd = MAX(channel_max_fd, wfd);
channel_max_fd = MAX(channel_max_fd, efd);
/* XXX set close-on-exec -markus */
c->rfd = rfd;
c->wfd = wfd;
c->sock = (rfd == wfd) ? rfd : -1;
c->efd = efd;
c->extended_usage = extusage;
/* XXX ugly hack: nonblock is only set by the server */
if (nonblock && isatty(c->rfd)) {
debug("channel %d: rfd %d isatty", c->self, c->rfd);
c->isatty = 1;
if (!isatty(c->wfd)) {
error("channel %d: wfd %d is not a tty?",
c->self, c->wfd);
}
} else {
c->isatty = 0;
}
/* enable nonblocking mode */
if (nonblock) {
if (rfd != -1)
set_nonblock(rfd);
if (wfd != -1)
set_nonblock(wfd);
if (efd != -1)
set_nonblock(efd);
}
}
/*
* Allocate a new channel object and set its type and socket. This will cause
* remote_name to be freed.
*/
Channel *
channel_new(char *ctype, int type, int rfd, int wfd, int efd,
int window, int maxpack, int extusage, char *remote_name, int nonblock)
{
int i, found;
Channel *c;
/* Do initial allocation if this is the first call. */
if (channels_alloc == 0) {
chan_init();
channels_alloc = 10;
channels = xmalloc(channels_alloc * sizeof(Channel *));
for (i = 0; i < channels_alloc; i++)
channels[i] = NULL;
/*
* Kludge: arrange a call to channel_stop_listening if we
* terminate with fatal().
*/
fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL);
}
/* Try to find a free slot where to put the new channel. */
for (found = -1, i = 0; i < channels_alloc; i++)
if (channels[i] == NULL) {
/* Found a free slot. */
found = i;
break;
}
if (found == -1) {
/* There are no free slots. Take last+1 slot and expand the array. */
found = channels_alloc;
channels_alloc += 10;
debug2("channel: expanding %d", channels_alloc);
channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
for (i = found; i < channels_alloc; i++)
channels[i] = NULL;
}
/* Initialize and return new channel. */
c = channels[found] = xmalloc(sizeof(Channel));
buffer_init(&c->input);
buffer_init(&c->output);
buffer_init(&c->extended);
chan_init_iostates(c);
channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
c->self = found;
c->type = type;
c->ctype = ctype;
c->local_window = window;
c->local_window_max = window;
c->local_consumed = 0;
c->local_maxpacket = maxpack;
c->remote_id = -1;
c->remote_name = remote_name;
c->remote_window = 0;
c->remote_maxpacket = 0;
c->cb_fn = NULL;
c->cb_arg = NULL;
c->cb_event = 0;
c->dettach_user = NULL;
c->input_filter = NULL;
debug("channel %d: new [%s]", found, remote_name);
return c;
}
/* Close all channel fd/socket. */
void
channel_close_fds(Channel *c)
{
debug3("channel_close_fds: channel %d: r %d w %d e %d",
c->self, c->rfd, c->wfd, c->efd);
if (c->sock != -1) {
close(c->sock);
c->sock = -1;
}
if (c->rfd != -1) {
close(c->rfd);
c->rfd = -1;
}
if (c->wfd != -1) {
close(c->wfd);
c->wfd = -1;
}
if (c->efd != -1) {
close(c->efd);
c->efd = -1;
}
}
/* Free the channel and close its fd/socket. */
void
channel_free(Channel *c)
{
char *s;
int i, n;
for (n = 0, i = 0; i < channels_alloc; i++)
if (channels[i])
n++;
debug("channel_free: channel %d: %s, nchannels %d", c->self,
c->remote_name ? c->remote_name : "???", n);
s = channel_open_message();
debug3("channel_free: status: %s", s);
xfree(s);
if (c->dettach_user != NULL) {
debug("channel_free: channel %d: dettaching channel user", c->self);
c->dettach_user(c->self, NULL);
}
if (c->sock != -1)
shutdown(c->sock, SHUT_RDWR);
channel_close_fds(c);
buffer_free(&c->input);
buffer_free(&c->output);
buffer_free(&c->extended);
if (c->remote_name) {
xfree(c->remote_name);
c->remote_name = NULL;
}
channels[c->self] = NULL;
xfree(c);
}
/*
* Stops listening for channels, and removes any unix domain sockets that we
* might have.
*/
void
channel_stop_listening()
{
int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c != NULL) {
switch (c->type) {
case SSH_CHANNEL_AUTH_SOCKET:
close(c->sock);
unlink(c->path);
channel_free(c);
break;
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_X11_LISTENER:
close(c->sock);
channel_free(c);
break;
default:
break;
}
}
}
}
/*
* Closes the sockets/fds of all channels. This is used to close extra file
* descriptors after a fork.
*/
void
channel_close_all()
{
int i;
for (i = 0; i < channels_alloc; i++)
if (channels[i] != NULL)
channel_close_fds(channels[i]);
}
/*
* Returns true if no channel has too much buffered data, and false if one or
* more channel is overfull.
*/
int
channel_not_very_much_buffered_data()
{
u_int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) {
debug("channel %d: big input buffer %d",
c->self, buffer_len(&c->input));
return 0;
}
if (buffer_len(&c->output) > packet_get_maxsize()) {
debug("channel %d: big output buffer %d",
c->self, buffer_len(&c->output));
return 0;
}
}
}
return 1;
}
/* Returns true if any channel is still open. */
int
channel_still_open()
{
int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c == NULL)
continue;
switch (c->type) {
case SSH_CHANNEL_X11_LISTENER:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
continue;
case SSH_CHANNEL_LARVAL:
if (!compat20)
fatal("cannot happen: SSH_CHANNEL_LARVAL");
continue;
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
return 1;
case SSH_CHANNEL_INPUT_DRAINING:
case SSH_CHANNEL_OUTPUT_DRAINING:
if (!compat13)
fatal("cannot happen: OUT_DRAIN");
return 1;
default:
fatal("channel_still_open: bad channel type %d", c->type);
/* NOTREACHED */
}
}
return 0;
}
/* Returns the id of an open channel suitable for keepaliving */
int
channel_find_open()
{
int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c == NULL)
continue;
switch (c->type) {
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_X11_LISTENER:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
continue;
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
return i;
case SSH_CHANNEL_INPUT_DRAINING:
case SSH_CHANNEL_OUTPUT_DRAINING:
if (!compat13)
fatal("cannot happen: OUT_DRAIN");
return i;
default:
fatal("channel_find_open: bad channel type %d", c->type);
/* NOTREACHED */
}
}
return -1;
}
/*
* Returns a message describing the currently open forwarded connections,
* suitable for sending to the client. The message contains crlf pairs for
* newlines.
*/
char *
channel_open_message()
{
Buffer buffer;
Channel *c;
char buf[1024], *cp;
int i;
buffer_init(&buffer);
snprintf(buf, sizeof buf, "The following connections are open:\r\n");
buffer_append(&buffer, buf, strlen(buf));
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c == NULL)
continue;
switch (c->type) {
case SSH_CHANNEL_X11_LISTENER:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_ZOMBIE:
continue;
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
case SSH_CHANNEL_INPUT_DRAINING:
case SSH_CHANNEL_OUTPUT_DRAINING:
snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
c->self, c->remote_name,
c->type, c->remote_id,
c->istate, buffer_len(&c->input),
c->ostate, buffer_len(&c->output),
c->rfd, c->wfd);
buffer_append(&buffer, buf, strlen(buf));
continue;
default:
fatal("channel_open_message: bad channel type %d", c->type);
/* NOTREACHED */
}
}
buffer_append(&buffer, "\0", 1);
cp = xstrdup(buffer_ptr(&buffer));
buffer_free(&buffer);
return cp;
}
void
channel_send_open(int id)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_send_open: %d: bad id", id);
return;
}
debug("send channel open %d", id);
packet_start(SSH2_MSG_CHANNEL_OPEN);
packet_put_cstring(c->ctype);
packet_put_int(c->self);
packet_put_int(c->local_window);
packet_put_int(c->local_maxpacket);
packet_send();
}
void
channel_request(int id, char *service, int wantconfirm)
{
channel_request_start(id, service, wantconfirm);
packet_send();
debug("channel request %d: %s", id, service) ;
}
void
channel_request_start(int id, char *service, int wantconfirm)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_request: %d: bad id", id);
return;
}
packet_start(SSH2_MSG_CHANNEL_REQUEST);
packet_put_int(c->remote_id);
packet_put_cstring(service);
packet_put_char(wantconfirm);
}
void
channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_register_callback: %d: bad id", id);
return;
}
c->cb_event = mtype;
c->cb_fn = fn;
c->cb_arg = arg;
}
void
channel_register_cleanup(int id, channel_callback_fn *fn)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_register_cleanup: %d: bad id", id);
return;
}
c->dettach_user = fn;
}
void
channel_cancel_cleanup(int id)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_cancel_cleanup: %d: bad id", id);
return;
}
c->dettach_user = NULL;
}
void
channel_register_filter(int id, channel_filter_fn *fn)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
log("channel_register_filter: %d: bad id", id);
return;
}
c->input_filter = fn;
}
void
channel_set_fds(int id, int rfd, int wfd, int efd,
int extusage, int nonblock)
{
Channel *c = channel_lookup(id);
if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
fatal("channel_activate for non-larval channel %d.", id);
channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
c->type = SSH_CHANNEL_OPEN;
/* XXX window size? */
c->local_window = c->local_window_max = c->local_maxpacket * 2;
packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
packet_put_int(c->remote_id);
packet_put_int(c->local_window);
packet_send();
}
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