[mux.c]
fix bug introduced in mux rewrite:
In a mux master, when a socket to a mux slave closes before its server
session (as may occur when the slave has been signalled), gracefully
close the server session rather than deleting its channel immediately.
A server may have more messages on that channel to send (e.g. an exit
message) that will fatal() the client if they are sent to a channel that
has been prematurely deleted.
spotted by imorgan AT nas.nasa.gov
[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@
[mux.c sshpty.h clientloop.c sshtty.c]
quell tc[gs]etattr warnings when forcing a tty (ssh -tt), since we
usually don't actually have a tty to read/set; bz#1686 ok dtucker@
[mux.c]
fall back to creating a new TCP connection on most multiplexing errors
(socket connect fail, invalid version, refused permittion, corrupted
messages, etc.); bz #1329 ok dtucker@
[clientloop.h channels.h clientloop.c channels.c mux.c]
The multiplexing escape char handler commit last night introduced a
small memory leak per session; plug it.
[clientloop.h mux.c channels.c clientloop.c channels.h]
Enable ~ escapes for multiplex slave sessions; give each channel
its own escape state and hook the escape filters up to muxed
channels. bz #1331
Mux slaves do not currently support the ~^Z and ~& escapes.
NB. this change cranks the mux protocol version, so a new ssh
mux client will not be able to connect to a running old ssh
mux master.
ok dtucker@
[openbsd-compat/fmt_scaled.c openbsd-compat/openbsd-compat.h]
Fix compilation on Linux, including pulling in fmt_scaled(3)
implementation from OpenBSD's libutil.
[clientloop.c clientloop.h ssh.c mux.c]
tidy up session multiplexing code, moving it into its own file and
making the function names more consistent - making ssh.c and
clientloop.c a fair bit more readable.
ok markus@
