- stevesk@cvs.openbsd.org 2001/04/14 16:33:20

     [clientloop.c packet.h session.c ssh.c ttymodes.c ttymodes.h]
     protocol 2 tty modes support; ok markus@

7 files changed, 229 insertions, 130 deletions

diff --git a/ChangeLog b/ChangeLog
index 727db9604..53dd06de8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,9 @@
    - markus@cvs.openbsd.org 2001/04/14 16:27:57
      [ssh-add.c]
      use clear_pass instead of xfree()
+   - stevesk@cvs.openbsd.org 2001/04/14 16:33:20
+     [clientloop.c packet.h session.c ssh.c ttymodes.c ttymodes.h]
+     protocol 2 tty modes support; ok markus@
 
 20010414
  - Sync with OpenBSD glob.c, strlcat.c and vis.c changes
@@ -5075,4 +5078,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1113 2001/04/14 23:10:09 mouring Exp $
+$Id: ChangeLog,v 1.1114 2001/04/14 23:13:02 mouring Exp $
diff --git a/clientloop.c b/clientloop.c
index 94d2ec60b..24ea0dec0 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.61 2001/04/08 11:27:33 markus Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.62 2001/04/14 16:33:20 stevesk Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -79,6 +79,7 @@ RCSID("$OpenBSD: clientloop.c,v 1.61 2001/04/08 11:27:33 markus Exp $");
 #include "clientloop.h"
 #include "authfd.h"
 #include "atomicio.h"
+#include "sshtty.h"
 
 /* import options */
 extern Options options;
@@ -101,15 +102,6 @@ extern char *host;
  */
 static volatile int received_window_change_signal = 0;
 
-/* Terminal modes, as saved by enter_raw_mode. */
-static struct termios saved_tio;
-
-/*
- * Flag indicating whether we are in raw mode.  This is used by
- * enter_raw_mode and leave_raw_mode.
- */
-static int in_raw_mode = 0;
-
 /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
 static int in_non_blocking_mode = 0;
 
@@ -136,46 +128,6 @@ int	session_ident = -1;
 /*XXX*/
 extern Kex *xxx_kex;
 
-/* Returns the user\'s terminal to normal mode if it had been put in raw mode. */
-
-void
-leave_raw_mode(void)
-{
-        if (!in_raw_mode)
-                return;
-        in_raw_mode = 0;
-        if (tcsetattr(fileno(stdin), TCSADRAIN, &saved_tio) < 0)
-                perror("tcsetattr");
-
-        fatal_remove_cleanup((void (*) (void *)) leave_raw_mode, NULL);
-}
-
-/* Puts the user\'s terminal in raw mode. */
-
-void
-enter_raw_mode(void)
-{
-        struct termios tio;
-
-        if (tcgetattr(fileno(stdin), &tio) < 0)
-                perror("tcgetattr");
-        saved_tio = tio;
-        tio.c_iflag |= IGNPAR;
-        tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
-        tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
-#ifdef IEXTEN
-        tio.c_lflag &= ~IEXTEN;
-#endif                          /* IEXTEN */
-        tio.c_oflag &= ~OPOST;
-        tio.c_cc[VMIN] = 1;
-        tio.c_cc[VTIME] = 0;
-        if (tcsetattr(fileno(stdin), TCSADRAIN, &tio) < 0)
-                perror("tcsetattr");
-        in_raw_mode = 1;
-
-        fatal_add_cleanup((void (*) (void *)) leave_raw_mode, NULL);
-}
-
 /* Restores stdin to blocking mode. */
 
 void
@@ -218,7 +170,7 @@ window_change_handler(int sig)
 void
 signal_handler(int sig)
 {
-        if (in_raw_mode)
+        if (in_raw_mode())
                 leave_raw_mode();
         if (in_non_blocking_mode)
                 leave_non_blocking();
@@ -796,7 +748,7 @@ client_channel_closed(int id, void *arg)
                 error("client_channel_closed: id %d != session_ident %d",
                     id, session_ident);
         session_closed = 1;
-        if (in_raw_mode)
+        if (in_raw_mode())
                 leave_raw_mode();
 }
 
diff --git a/packet.h b/packet.h
index e5432714e..0f5e71049 100644
--- a/packet.h
+++ b/packet.h
@@ -11,7 +11,7 @@
  * called by a name other than "ssh" or "Secure Shell".
  */
 
-/* RCSID("$OpenBSD: packet.h,v 1.21 2001/02/28 21:27:47 markus Exp $"); */
+/* RCSID("$OpenBSD: packet.h,v 1.22 2001/04/14 16:33:20 stevesk Exp $"); */
 
 #ifndef PACKET_H
 #define PACKET_H
@@ -178,8 +178,8 @@ extern int max_packet_size;
 int     packet_set_maxsize(int s);
 #define packet_get_maxsize() max_packet_size
 
-/* Stores tty modes from the fd into current packet. */
-void    tty_make_modes(int fd);
+/* Stores tty modes from the fd or tiop into current packet. */
+void    tty_make_modes(int fd, struct termios *tiop);
 
 /* Parses tty modes for the fd from the current packet. */
 void    tty_parse_modes(int fd, int *n_bytes_ptr);
diff --git a/session.c b/session.c
index 8da799335..ebefd91c4 100644
--- a/session.c
+++ b/session.c
@@ -33,7 +33,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: session.c,v 1.71 2001/04/06 21:00:12 markus Exp $");
+RCSID("$OpenBSD: session.c,v 1.72 2001/04/14 16:33:20 stevesk Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1603,7 +1603,7 @@ int
 session_pty_req(Session *s)
 {
         u_int len;
-        char *term_modes;       /* encoded terminal modes */
+        int n_bytes;
 
         if (no_pty_flag)
                 return 0;
@@ -1614,8 +1614,6 @@ session_pty_req(Session *s)
         s->row = packet_get_int();
         s->xpixel = packet_get_int();
         s->ypixel = packet_get_int();
-        term_modes = packet_get_string(&len);
-        packet_done();
 
         if (strcmp(s->term, "") == 0) {
                 xfree(s->term);
@@ -1628,7 +1626,6 @@ session_pty_req(Session *s)
                 s->ptyfd = -1;
                 s->ttyfd = -1;
                 error("session_pty_req: session %d alloc failed", s->self);
-                xfree(term_modes);
                 return 0;
         }
         debug("session_pty_req: session %d alloc %s", s->self, s->tty);
@@ -1641,10 +1638,12 @@ session_pty_req(Session *s)
         /* Get window size from the packet. */
         pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
 
+        /* Get tty modes from the packet. */
+        tty_parse_modes(s->ttyfd, &n_bytes);
+        packet_done();
+
         session_proctitle(s);
 
-        /* XXX parse and set terminal modes */
-        xfree(term_modes);
         return 1;
 }
 
diff --git a/ssh.c b/ssh.c
index 68ce17177..bd0d5ba9d 100644
--- a/ssh.c
+++ b/ssh.c
@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.114 2001/04/13 01:26:17 stevesk Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.115 2001/04/14 16:33:20 stevesk Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -67,6 +67,7 @@ RCSID("$OpenBSD: ssh.c,v 1.114 2001/04/13 01:26:17 stevesk Exp $");
 #include "misc.h"
 #include "kex.h"
 #include "mac.h"
+#include "sshtty.h"
 
 #ifdef HAVE___PROGNAME
 extern char *__progname;
@@ -879,7 +880,7 @@ ssh_session(void)
                 packet_put_int(ws.ws_ypixel);
 
                 /* Store tty modes in the packet. */
-                tty_make_modes(fileno(stdin));
+                tty_make_modes(fileno(stdin), NULL);
 
                 /* Send the packet, and wait for it to leave. */
                 packet_send();
@@ -983,6 +984,7 @@ ssh_session2_callback(int id, void *arg)
 {
         int len;
         int interactive = 0;
+        struct termios tio;
 
         debug("client_init id %d arg %ld", id, (long)arg);
 
@@ -1002,7 +1004,8 @@ ssh_session2_callback(int id, void *arg)
                 packet_put_int(ws.ws_row);
                 packet_put_int(ws.ws_xpixel);
                 packet_put_int(ws.ws_ypixel);
-                packet_put_cstring("");         /* XXX: encode terminal modes */
+                tio = get_saved_tio();
+                tty_make_modes(/*ignored*/ 0, &tio);
                 packet_send();
                 interactive = 1;
                 /* XXX wait for reply */
diff --git a/ttymodes.c b/ttymodes.c
index 65caf2ff8..9ce3fbcc4 100644
--- a/ttymodes.c
+++ b/ttymodes.c
@@ -2,10 +2,6 @@
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
- * Encoding and decoding of terminal modes in a portable way.
- * Much of the format is defined in ttymodes.h; it is included multiple times
- * into this file with the appropriate macro definitions to generate the
- * suitable code.
  *
  * 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
@@ -14,16 +10,56 @@
  * called by a name other than "ssh" or "Secure Shell".
  */
 
+/*
+ * SSH2 tty modes support by Kevin Steves.
+ * Copyright (c) 2001 Kevin Steves.  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.
+ */
+
+/*
+ * Encoding and decoding of terminal modes in a portable way.
+ * Much of the format is defined in ttymodes.h; it is included multiple times
+ * into this file with the appropriate macro definitions to generate the
+ * suitable code.
+ */
+
 #include "includes.h"
-RCSID("$OpenBSD: ttymodes.c,v 1.11 2001/03/10 15:02:05 stevesk Exp $");
+RCSID("$OpenBSD: ttymodes.c,v 1.12 2001/04/14 16:33:20 stevesk Exp $");
 
 #include "packet.h"
 #include "log.h"
 #include "ssh1.h"
+#include "compat.h"
+#include "buffer.h"
+#include "bufaux.h"
 
-#define TTY_OP_END      0
-#define TTY_OP_ISPEED   192     /* int follows */
-#define TTY_OP_OSPEED   193     /* int follows */
+#define TTY_OP_END              0
+/*
+ * uint32 (u_int) follows speed in SSH1 and SSH2
+ */
+#define TTY_OP_ISPEED_PROTO1    192
+#define TTY_OP_OSPEED_PROTO1    193
+#define TTY_OP_ISPEED_PROTO2    128
+#define TTY_OP_OSPEED_PROTO2    129
 
 /*
  * Converts POSIX speed_t to a baud rate.  The values of the
@@ -122,7 +158,7 @@ static speed_t
 baud_to_speed(int baud)
 {
         switch (baud) {
-                case 0:
+        case 0:
                 return B0;
         case 50:
                 return B50;
@@ -206,41 +242,72 @@ baud_to_speed(int baud)
 
 /*
  * Encodes terminal modes for the terminal referenced by fd
- * in a portable manner, and appends the modes to a packet
+ * or tiop in a portable manner, and appends the modes to a packet
  * being constructed.
  */
 void
-tty_make_modes(int fd)
+tty_make_modes(int fd, struct termios *tiop)
 {
         struct termios tio;
         int baud;
+        Buffer buf;
+        int tty_op_ospeed, tty_op_ispeed;
+        void (*put_arg)(Buffer *, u_int);
 
-        if (tcgetattr(fd, &tio) < 0) {
-                packet_put_char(TTY_OP_END);
-                log("tcgetattr: %.100s", strerror(errno));
-                return;
+        buffer_init(&buf);
+        if (compat20) {
+                tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
+                tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
+                put_arg = buffer_put_int;
+        } else {
+                tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
+                tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
+                put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
         }
+
+        if (tiop == NULL) {
+                if (tcgetattr(fd, &tio) == -1) {
+                        log("tcgetattr: %.100s", strerror(errno));
+                        goto end;
+                }
+        } else
+                tio = *tiop;
+
         /* Store input and output baud rates. */
         baud = speed_to_baud(cfgetospeed(&tio));
-        packet_put_char(TTY_OP_OSPEED);
-        packet_put_int(baud);
+        debug2("tty_make_modes: ospeed %d", baud);
+        buffer_put_char(&buf, tty_op_ospeed);
+        buffer_put_int(&buf, baud);
         baud = speed_to_baud(cfgetispeed(&tio));
-        packet_put_char(TTY_OP_ISPEED);
-        packet_put_int(baud);
+        debug2("tty_make_modes: ispeed %d", baud);
+        buffer_put_char(&buf, tty_op_ispeed);
+        buffer_put_int(&buf, baud);
 
         /* Store values of mode flags. */
 #define TTYCHAR(NAME, OP) \
-  packet_put_char(OP); packet_put_char(tio.c_cc[NAME]);
+        debug2("tty_make_modes: %d %d", OP, tio.c_cc[NAME]); \
+        buffer_put_char(&buf, OP); \
+        put_arg(&buf, tio.c_cc[NAME]);
+
 #define TTYMODE(NAME, FIELD, OP) \
-  packet_put_char(OP); packet_put_char((tio.FIELD & NAME) != 0);
+        debug2("tty_make_modes: %d %d", OP, ((tio.FIELD & NAME) != 0)); \
+        buffer_put_char(&buf, OP); \
+        put_arg(&buf, ((tio.FIELD & NAME) != 0));
 
 #include "ttymodes.h"
 
 #undef TTYCHAR
 #undef TTYMODE
 
+end:
         /* Mark end of mode data. */
-        packet_put_char(TTY_OP_END);
+        buffer_put_char(&buf, TTY_OP_END);
+        if (compat20)
+                packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
+        else
+                packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
+        buffer_free(&buf);
+        return;
 }
 
 /*
@@ -254,14 +321,30 @@ tty_parse_modes(int fd, int *n_bytes_ptr)
         int opcode, baud;
         int n_bytes = 0;
         int failure = 0;
+        u_int (*get_arg)(void);
+        int arg, arg_size;
+
+        if (compat20) {
+                *n_bytes_ptr = packet_get_int();
+                debug2("tty_parse_modes: SSH2 n_bytes %d", *n_bytes_ptr);
+                if (*n_bytes_ptr == 0)
+                        return;
+                get_arg = packet_get_int;
+                arg_size = 4;
+        } else {
+                get_arg = packet_get_char;
+                arg_size = 1;
+        }
 
         /*
          * Get old attributes for the terminal.  We will modify these
          * flags. I am hoping that if there are any machine-specific
          * modes, they will initially have reasonable values.
          */
-        if (tcgetattr(fd, &tio) < 0)
+        if (tcgetattr(fd, &tio) == -1) {
+                log("tcgetattr: %.100s", strerror(errno));
                 failure = -1;
+        }
 
         for (;;) {
                 n_bytes += 1;
@@ -270,32 +353,40 @@ tty_parse_modes(int fd, int *n_bytes_ptr)
                 case TTY_OP_END:
                         goto set;
 
-                case TTY_OP_ISPEED:
+                /* XXX: future conflict possible */
+                case TTY_OP_ISPEED_PROTO1:
+                case TTY_OP_ISPEED_PROTO2:
                         n_bytes += 4;
                         baud = packet_get_int();
-                        if (failure != -1 && cfsetispeed(&tio, baud_to_speed(baud)) < 0)
+                        debug2("tty_parse_modes: ispeed %d", baud);
+                        if (failure != -1 && cfsetispeed(&tio, baud_to_speed(baud)) == -1)
                                 error("cfsetispeed failed for %d", baud);
                         break;
 
-                case TTY_OP_OSPEED:
+                /* XXX: future conflict possible */
+                case TTY_OP_OSPEED_PROTO1:
+                case TTY_OP_OSPEED_PROTO2:
                         n_bytes += 4;
                         baud = packet_get_int();
-                        if (failure != -1 && cfsetospeed(&tio, baud_to_speed(baud)) < 0)
+                        debug2("tty_parse_modes: ospeed %d", baud);
+                        if (failure != -1 && cfsetospeed(&tio, baud_to_speed(baud)) == -1)
                                 error("cfsetospeed failed for %d", baud);
                         break;
 
-#define TTYCHAR(NAME, OP)                               \
-        case OP:                                        \
-          n_bytes += 1;                                 \
-          tio.c_cc[NAME] = packet_get_char();           \
+#define TTYCHAR(NAME, OP) \
+        case OP: \
+          n_bytes += arg_size; \
+          tio.c_cc[NAME] = get_arg(); \
+          debug2("tty_parse_modes: %d %d", OP, tio.c_cc[NAME]); \
           break;
-#define TTYMODE(NAME, FIELD, OP)                        \
-        case OP:                                        \
-          n_bytes += 1;                                 \
-          if (packet_get_char())                        \
-            tio.FIELD |= NAME;                          \
-          else                                          \
-            tio.FIELD &= ~NAME;                         \
+#define TTYMODE(NAME, FIELD, OP) \
+        case OP: \
+          n_bytes += arg_size; \
+          if ((arg = get_arg())) \
+            tio.FIELD |= NAME; \
+          else \
+            tio.FIELD &= ~NAME; \
+          debug2("tty_parse_modes: %d %d", OP, arg); \
           break;
 
 #include "ttymodes.h"
@@ -306,48 +397,66 @@ tty_parse_modes(int fd, int *n_bytes_ptr)
                 default:
                         debug("Ignoring unsupported tty mode opcode %d (0x%x)",
                               opcode, opcode);
-                        /*
-                         * Opcodes 0 to 127 are defined to have
-                         * a one-byte argument.
-                         */
-                        if (opcode >= 0 && opcode < 128) {
-                                n_bytes += 1;
-                                (void) packet_get_char();
-                                break;
+                        if (!compat20) {
+                                /*
+                                 * SSH1:
+                                 * Opcodes 1 to 127 are defined to have
+                                 * a one-byte argument.
+                                 * Opcodes 128 to 159 are defined to have
+                                 * an integer argument.
+                                 */
+                                if (opcode > 0 && opcode < 128) {
+                                        n_bytes += 1;
+                                        (void) packet_get_char();
+                                        break;
+                                } else if (opcode >= 128 && opcode < 160) {
+                                        n_bytes += 4;
+                                        (void) packet_get_int();
+                                        break;
+                                } else {
+                                        /*
+                                         * It is a truly undefined opcode (160 to 255).
+                                         * We have no idea about its arguments.  So we
+                                         * must stop parsing.  Note that some data may be
+                                         * left in the packet; hopefully there is nothing
+                                         * more coming after the mode data.
+                                         */
+                                        log("parse_tty_modes: unknown opcode %d", opcode);
+                                        packet_integrity_check(0, 1, SSH_CMSG_REQUEST_PTY);
+                                        goto set;
+                                }
                         } else {
                                 /*
-                                 * Opcodes 128 to 159 are defined to have
-                                 * an integer argument.
+                                 * SSH2:
+                                 * Opcodes 0 to 159 are defined to have
+                                 * a uint32 argument.
+                                 * Opcodes 160 to 255 are undefined and
+                                 * cause parsing to stop.
                                  */
-                                if (opcode >= 128 && opcode < 160) {
+                                if (opcode > 0 && opcode < 160) {
                                         n_bytes += 4;
                                         (void) packet_get_int();
                                         break;
+                                } else {
+                                        log("parse_tty_modes: unknown opcode %d", opcode);
+                                        goto set;
                                 }
-                        }
-                        /*
-                         * It is a truly undefined opcode (160 to 255).
-                         * We have no idea about its arguments.  So we
-                         * must stop parsing.  Note that some data may be
-                         * left in the packet; hopefully there is nothing
-                         * more coming after the mode data.
-                         */
-                        log("parse_tty_modes: unknown opcode %d", opcode);
-                        packet_integrity_check(0, 1, SSH_CMSG_REQUEST_PTY);
-                        goto set;
+                        }
                 }
         }
 
 set:
         if (*n_bytes_ptr != n_bytes) {
                 *n_bytes_ptr = n_bytes;
+                log("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
+                    *n_bytes_ptr, n_bytes);
                 return;         /* Don't process bytes passed */
         }
         if (failure == -1)
                 return;         /* Packet parsed ok but tty stuff failed */
 
         /* Set the new modes for the terminal. */
-        if (tcsetattr(fd, TCSANOW, &tio) < 0)
+        if (tcsetattr(fd, TCSANOW, &tio) == -1)
                 log("Setting tty modes failed: %.100s", strerror(errno));
         return;
 }
diff --git a/ttymodes.h b/ttymodes.h
index 860fd0a9c..ad980e98c 100644
--- a/ttymodes.h
+++ b/ttymodes.h
@@ -1,6 +1,6 @@
+/* RCSID("$OpenBSD: ttymodes.h,v 1.11 2001/04/14 16:33:20 stevesk Exp $"); */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
- *      SGTTY stuff contributed by Janne Snabb <snabb@niksula.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  *
@@ -11,14 +11,47 @@
  * called by a name other than "ssh" or "Secure Shell".
  */
 
-/* RCSID("$OpenBSD: ttymodes.h,v 1.10 2001/03/10 15:02:05 stevesk Exp $"); */
+/*
+ * SSH2 tty modes support by Kevin Steves.
+ * Copyright (c) 2001 Kevin Steves.  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.
+ */
 
-/* The tty mode description is a stream of bytes.  The stream consists of
+/*
+ * SSH1:
+ * The tty mode description is a stream of bytes.  The stream consists of
  * opcode-arguments pairs.  It is terminated by opcode TTY_OP_END (0).
  * Opcodes 1-127 have one-byte arguments.  Opcodes 128-159 have integer
  * arguments.  Opcodes 160-255 are not yet defined, and cause parsing to
  * stop (they should only be used after any other data).
  *
+ * SSH2:
+ * Differences between SSH1 and SSH2 terminal mode encoding include:
+ * 1. Encoded terminal modes are represented as a string, and a stream
+ *    of bytes within that string.
+ * 2. Opcode arguments are uint32 (1-159); 160-255 remain undefined.
+ * 3. The values for TTY_OP_ISPEED and TTY_OP_OSPEED are different;
+ *    128 and 129 vs. 192 and 193 respectively.
+ *
  * The client puts in the stream any modes it knows about, and the
  * server ignores any modes it does not know about.  This allows some degree
  * of machine-independence, at least between systems that use a posix-like