- 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 79ebe047..cc71885f 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);