Re: ssh channel window and adjustment

[Jon Bright <jon%siliconcircus.com@localhost>]

On Wed, 2003-01-22 at 13:20, Sombody Somewhere wrote:
> 
> It seems to me that OpenSSH client sends
> SSH_MSG_CHANNEL_WINDOW_ADJUST, when it writes more
> than the half of its own channel window size(the

No, this isn't correct.  It sends it (afair, I don't have time to check
the code) when the remaining space in the incoming channel window is
less than half the maximum space in the incoming channel window.

> server is obliged no to write its output untill the
> client sends it adjust message. This way the server is
>  obliged to allocate great amount of data and keep it

At no point is the server obliged to allocate lots of memory - it can
just stop accepting more data from whatever's generating the data.  So
if 'ls -lR' is generating the console output, the sshd stops accepting
the output from 'ls -lR', which in turn sleeps.  When the client sends
an adjust message, the server sends more data until the window's again
full.

-- 
Jon Bright
Lead Programmer, Silicon Circus Ltd.
http://www.siliconcircus.com/