- 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@

1 files changed, 14 insertions, 4 deletions

diff --git a/channels.h b/channels.h
index 79ebe047a..cc71885f4 100644
--- a/channels.h
+++ b/channels.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.h,v 1.102 2010/01/11 01:39:46 dtucker Exp $ */
+/* $OpenBSD: channels.h,v 1.103 2010/01/26 01:28:35 djm Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -53,7 +53,9 @@
 #define SSH_CHANNEL_CONNECTING          12
 #define SSH_CHANNEL_DYNAMIC             13
 #define SSH_CHANNEL_ZOMBIE              14      /* Almost dead. */
-#define SSH_CHANNEL_MAX_TYPE            15
+#define SSH_CHANNEL_MUX_LISTENER        15      /* Listener for mux conn. */
+#define SSH_CHANNEL_MUX_CLIENT          16      /* Conn. to mux slave */
+#define SSH_CHANNEL_MAX_TYPE            17
 
 struct Channel;
 typedef struct Channel Channel;
@@ -81,6 +83,9 @@ struct channel_connect {
         struct addrinfo *ai, *aitop;
 };
 
+/* Callbacks for mux channels back into client-specific code */
+typedef int mux_callback_fn(struct Channel *);
+
 struct Channel {
         int     type;           /* channel type/state */
         int     self;           /* my own channel identifier */
@@ -92,7 +97,7 @@ struct Channel {
         int     wfd;            /* write fd */
         int     efd;            /* extended fd */
         int     sock;           /* sock fd */
-        int     ctl_fd;         /* control fd (client sharing) */
+        int     ctl_chan;       /* control channel (multiplexed connections) */
         int     isatty;         /* rfd is a tty */
         int     wfd_isatty;     /* wfd is a tty */
         int     client_tty;     /* (client) TTY has been requested */
@@ -142,6 +147,10 @@ struct Channel {
 
         /* non-blocking connect */
         struct channel_connect  connect_ctx;
+
+        /* multiplexing protocol hook, called for each packet received */
+        mux_callback_fn         *mux_rcb;
+        void                    *mux_ctx;
 };
 
 #define CHAN_EXTENDED_IGNORE            0
@@ -172,6 +181,7 @@ struct Channel {
 #define CHAN_CLOSE_RCVD                 0x02
 #define CHAN_EOF_SENT                   0x04
 #define CHAN_EOF_RCVD                   0x08
+#define CHAN_LOCAL                      0x10
 
 #define CHAN_RBUF       16*1024
 
@@ -243,7 +253,7 @@ void	 channel_clear_adm_permitted_opens(void);
 void     channel_print_adm_permitted_opens(void);
 int      channel_input_port_forward_request(int, int);
 Channel *channel_connect_to(const char *, u_short, char *, char *);
-Channel *channel_connect_stdio_fwd(const char*, u_short);
+Channel *channel_connect_stdio_fwd(const char*, u_short, int, int);
 Channel *channel_connect_by_listen_address(u_short, char *, char *);
 int      channel_request_remote_forwarding(const char *, u_short,
              const char *, u_short);