4 files changed, 39 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index 451f1b323..3c522ea36 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,10 @@
    - stevesk@cvs.openbsd.org 2005/12/28 22:46:06
      [canohost.c channels.c clientloop.c]
      use 'break-in' for consistency; ok deraadt@ ok and input jmc@
+   - reyk@cvs.openbsd.org 2005/12/30 15:56:37
+     [channels.c channels.h clientloop.c]
+     add channel output filter interface.
+     ok djm@, suggested by markus@
 
 20051229
  - (tim) [buildpkg.sh.in] grep for $SSHDUID instead of $SSHDGID on /etc/passwd
@@ -3558,4 +3562,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.4053 2005/12/31 05:19:53 djm Exp $
+$Id: ChangeLog,v 1.4054 2005/12/31 05:22:32 djm Exp $
diff --git a/channels.c b/channels.c
index b431532a3..ed5903f6f 100644
--- a/channels.c
+++ b/channels.c
@@ -39,7 +39,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: channels.c,v 1.230 2005/12/28 22:46:06 stevesk Exp $");
+RCSID("$OpenBSD: channels.c,v 1.231 2005/12/30 15:56:36 reyk Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -58,8 +58,6 @@ RCSID("$OpenBSD: channels.c,v 1.230 2005/12/28 22:46:06 stevesk Exp $");
 
 /* -- channel core */
 
-#define CHAN_RBUF       16*1024
-
 /*
  * Pointer to an array containing all allocated channels.  The array is
  * dynamically extended as needed.
@@ -301,6 +299,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd,
         c->confirm = NULL;
         c->confirm_ctx = NULL;
         c->input_filter = NULL;
+        c->output_filter = NULL;
         debug("channel %d: new [%s]", found, remote_name);
         return c;
 }
@@ -681,7 +680,8 @@ channel_cancel_cleanup(int id)
         c->detach_close = 0;
 }
 void
-channel_register_filter(int id, channel_filter_fn *fn)
+channel_register_filter(int id, channel_infilter_fn *ifn,
+    channel_outfilter_fn *ofn)
 {
         Channel *c = channel_lookup(id);
 
@@ -689,7 +689,8 @@ channel_register_filter(int id, channel_filter_fn *fn)
                 logit("channel_register_filter: %d: bad id", id);
                 return;
         }
-        c->input_filter = fn;
+        c->input_filter = ifn;
+        c->output_filter = ofn;
 }
 
 void
@@ -1454,7 +1455,7 @@ static int
 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
 {
         struct termios tio;
-        u_char *data;
+        u_char *data = NULL, *buf;
         u_int dlen;
         int len;
 
@@ -1462,11 +1463,22 @@ channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
         if (c->wfd != -1 &&
             FD_ISSET(c->wfd, writeset) &&
             buffer_len(&c->output) > 0) {
+                if (c->output_filter != NULL) {
+                        if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
+                                debug2("channel %d: filter stops", c->self);
+                                chan_read_failed(c);
+                        }
+                } else if (c->datagram) {
+                        buf = data = buffer_get_string(&c->output, &dlen);
+                } else {
+                        buf = data = buffer_ptr(&c->output);
+                        dlen = buffer_len(&c->output);
+                }
+
                 if (c->datagram) {
-                        data = buffer_get_string(&c->output, &dlen);
                         /* ignore truncated writes, datagrams might get lost */
                         c->local_consumed += dlen + 4;
-                        len = write(c->wfd, data, dlen);
+                        len = write(c->wfd, buf, dlen);
                         xfree(data);
                         if (len < 0 && (errno == EINTR || errno == EAGAIN))
                                 return 1;
@@ -1486,7 +1498,8 @@ channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
                 if (compat20 && c->wfd_isatty)
                         dlen = MIN(dlen, 8*1024);
 #endif
-                len = write(c->wfd, data, dlen);
+
+                len = write(c->wfd, buf, dlen);
                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
                         return 1;
                 if (len <= 0) {
@@ -1503,14 +1516,14 @@ channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
                         }
                         return -1;
                 }
-                if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
+                if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
                         if (tcgetattr(c->wfd, &tio) == 0 &&
                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
                                 /*
                                  * Simulate echo to reduce the impact of
                                  * traffic analysis. We need to match the
                                  * size of a SSH2_MSG_CHANNEL_DATA message
-                                 * (4 byte channel id + data)
+                                 * (4 byte channel id + buf)
                                  */
                                 packet_send_ignore(4 + len);
                                 packet_send();
diff --git a/channels.h b/channels.h
index 7990fe147..a97dd9007 100644
--- a/channels.h
+++ b/channels.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: channels.h,v 1.82 2005/12/12 13:46:18 markus Exp $    */
+/*      $OpenBSD: channels.h,v 1.83 2005/12/30 15:56:37 reyk Exp $      */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -63,7 +63,8 @@ struct Channel;
 typedef struct Channel Channel;
 
 typedef void channel_callback_fn(int, void *);
-typedef int channel_filter_fn(struct Channel *, char *, int);
+typedef int channel_infilter_fn(struct Channel *, char *, int);
+typedef u_char *channel_outfilter_fn(struct Channel *, u_char **, u_int *);
 
 struct Channel {
         int     type;           /* channel type/state */
@@ -111,7 +112,8 @@ struct Channel {
         int                     detach_close;
 
         /* filter */
-        channel_filter_fn       *input_filter;
+        channel_infilter_fn     *input_filter;
+        channel_outfilter_fn    *output_filter;
 
         int     datagram;       /* keep boundaries */
 };
@@ -145,6 +147,8 @@ struct Channel {
 #define CHAN_EOF_SENT                   0x04
 #define CHAN_EOF_RCVD                   0x08
 
+#define CHAN_RBUF       16*1024
+
 /* check whether 'efd' is still in use */
 #define CHANNEL_EFD_INPUT_ACTIVE(c) \
         (compat20 && c->extended_usage == CHAN_EXTENDED_READ && \
@@ -169,7 +173,7 @@ void	 channel_send_open(int);
 void     channel_request_start(int, char *, int);
 void     channel_register_cleanup(int, channel_callback_fn *, int);
 void     channel_register_confirm(int, channel_callback_fn *, void *);
-void     channel_register_filter(int, channel_filter_fn *);
+void     channel_register_filter(int, channel_infilter_fn *, channel_outfilter_fn *);
 void     channel_cancel_cleanup(int);
 int      channel_close_fd(int *);
 void     channel_send_window_changes(void);
diff --git a/clientloop.c b/clientloop.c
index a71552cad..b76f7cfe0 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -59,7 +59,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: clientloop.c,v 1.148 2005/12/28 22:46:06 stevesk Exp $");
+RCSID("$OpenBSD: clientloop.c,v 1.149 2005/12/30 15:56:37 reyk Exp $");
 
 #include "ssh.h"
 #include "ssh1.h"
@@ -1386,7 +1386,7 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
                 session_ident = ssh2_chan_id;
                 if (escape_char != SSH_ESCAPECHAR_NONE)
                         channel_register_filter(session_ident,
-                            simple_escape_filter);
+                            simple_escape_filter, NULL);
                 if (session_ident != -1)
                         channel_register_cleanup(session_ident,
                             client_channel_closed, 0);