- djm@cvs.openbsd.org 2010/01/26 01:28:35
[channels.c channels.h clientloop.c clientloop.h mux.c nchan.c ssh.c]
rewrite ssh(1) multiplexing code to a more sensible protocol.
The new multiplexing code uses channels for the listener and
accepted control sockets to make the mux master non-blocking, so
no stalls when processing messages from a slave.
avoid use of fatal() in mux master protocol parsing so an errant slave
process cannot take down a running master.
implement requesting of port-forwards over multiplexed sessions. Any
port forwards requested by the slave are added to those the master has
established.
add support for stdio forwarding ("ssh -W host:port ...") in mux slaves.
document master/slave mux protocol so that other tools can use it to
control a running ssh(1). Note: there are no guarantees that this
protocol won't be incompatibly changed (though it is versioned).
feedback Salvador Fandino, dtucker@
channel changes ok markus@
diff --git a/clientloop.c b/clientloop.c
index 5793a6e..05f4720 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.216 2010/01/09 05:04:24 djm Exp $ */
+/* $OpenBSD: clientloop.c,v 1.217 2010/01/26 01:28:35 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -121,7 +121,7 @@
extern int no_shell_flag;
/* Control socket */
-extern int muxserver_sock;
+extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
/*
* Name of the host we are connecting to. This is the name given on the
@@ -146,7 +146,7 @@
static int in_non_blocking_mode = 0;
/* Common data for the client loop code. */
-static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
+volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
static int escape_char1; /* Escape character. (proto1 only) */
static int escape_pending1; /* Last character was an escape (proto1 only) */
static int last_was_cr; /* Last character was a newline. */
@@ -564,9 +564,6 @@
if (packet_have_data_to_write())
FD_SET(connection_out, *writesetp);
- if (muxserver_sock != -1)
- FD_SET(muxserver_sock, *readsetp);
-
/*
* Wait for something to happen. This will suspend the process until
* some selected descriptor can be read, written, or has some other
@@ -695,7 +692,7 @@
/* XXX supress on mux _client_ quietmode */
tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
- c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
+ c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
if (type == SSH2_MSG_CHANNEL_SUCCESS) {
debug2("%s request accepted on channel %d",
@@ -839,6 +836,7 @@
while (isspace(*++s))
;
+ /* XXX update list of forwards in options */
if (delete) {
cancel_port = 0;
cancel_host = hpdelim(&s); /* may be NULL */
@@ -936,7 +934,7 @@
escape_char);
buffer_append(berr, string, strlen(string));
- if (c && c->ctl_fd != -1) {
+ if (c && c->ctl_chan != -1) {
chan_read_failed(c);
chan_write_failed(c);
return 0;
@@ -946,7 +944,7 @@
case 'Z' - 64:
/* XXX support this for mux clients */
- if (c && c->ctl_fd != -1) {
+ if (c && c->ctl_chan != -1) {
noescape:
snprintf(string, sizeof string,
"%c%c escape not available to "
@@ -991,7 +989,7 @@
continue;
case '&':
- if (c && c->ctl_fd != -1)
+ if (c && c->ctl_chan != -1)
goto noescape;
/*
* Detach the program (continue to serve
@@ -1042,7 +1040,7 @@
continue;
case '?':
- if (c && c->ctl_fd != -1) {
+ if (c && c->ctl_chan != -1) {
snprintf(string, sizeof string,
"%c?\r\n\
Supported escape sequences:\r\n\
@@ -1091,7 +1089,7 @@
continue;
case 'C':
- if (c && c->ctl_fd != -1)
+ if (c && c->ctl_chan != -1)
goto noescape;
process_cmdline();
continue;
@@ -1327,8 +1325,6 @@
connection_in = packet_get_connection_in();
connection_out = packet_get_connection_out();
max_fd = MAX(connection_in, connection_out);
- if (muxserver_sock != -1)
- max_fd = MAX(max_fd, muxserver_sock);
if (!compat20) {
/* enable nonblocking unless tty */
@@ -1446,12 +1442,6 @@
/* Buffer input from the connection. */
client_process_net_input(readset);
- /* Accept control connections. */
- if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) {
- if (muxserver_accept_control())
- quit_pending = 1;
- }
-
if (quit_pending)
break;
@@ -1859,9 +1849,8 @@
chan_rcvd_eow(c);
} else if (strcmp(rtype, "exit-status") == 0) {
exitval = packet_get_int();
- if (c->ctl_fd != -1) {
- /* Dispatch to mux client */
- atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
+ if (c->ctl_chan != -1) {
+ mux_exit_message(c, exitval);
success = 1;
} else if (id == session_ident) {
/* Record exit value of local session */