Re: A couple of newbie questions about libssh in server mode.

[drbob <drbob@xxxxxxxxxxxx>]

I've solved Issue (3),  by freeing the session, and creating a new one...
	- the docs say you shouldn't need to do this.

Thoughts about (1) & (2) ?

On 8 Aug 2012, at 19:30, drbob wrote:

> 
> Dear libssh developers.
> 
> Thanks for this great library... 
> Only took me an hour or so, to get an SSH server embedded into our Software.
> 
> I'm a developer for Retroshare (http://retroshare.sourceforge.net), and we are planning to use libssh to provide
> a remote terminal interface so people can run RS on routers, and Raspberry-PI's, etc, and access from anywhere.
> 
> Would like to ask a few questions:
> 
> 1) SSH server private key.  At the moment, I'm using a rsa_host_key file which is registered using 
> 	ssh_bind_options_set(..., SSH_BIND_OPTIONS_RSAKEY, ...) 
> 
>  Can we load the private key from memory using a EVP_PKEY * structure (or similar)?
> 
> 2) For this initial code, I've just adapted your samplesshd.c code.
> 	-> open SSH_CHANNEL_SESSION.
> 	-> open a SHELL.
> 
> This is great for our initial Terminal style application. In the future we plan to stream data over this link, 
> and would like to create our own subsystem (or just explicitly name it, so it cannot be confused):
> 	-> open SSH_CHANNEL_SESSION.
> 	-> open a RS_DATA_LINK
> 
> The Tutorial, says this is outside its scope (fair enough ;), but I can't find any other documentation.
> Is there an example of how to do somewhere? 
> What is the best way to do this?
> 
> 
> 3) Using the samplesshd.c code, I can successfully connect once from an ssh client, but a second attempt hangs. 
> I'm assuming this is because I haven't cleaned up libssh properly after the first connection:
> 
> Real Code:  
> http://retroshare.svn.sourceforge.net/viewvc/retroshare/branches/v0.5-gxs-b1/retroshare-nogui/src/ssh/rssshd.cc?revision=5396&view=markup
> 
> Pseudo code:
> 	mBind = ssh_bind_new();
>       mSession = ssh_new();
>       ssh_bind_options_set( ....);
> 
>       while(1)
> 	{
>       	ssh_bind_listen(mBind);
>               ssh_bind_accept(...);
>               ssh_handle_key_exchange(...);
>               ...
> 		authUser();
>               setupChannel();
>               setupShell();
> 
>               read/write
> 
>               ssh_disconnect(mSession);
>      }
> 
> 
> Output for the Second Connection is:
> 
> [3] Enabling POLLOUT for socket
> [3] ssh_handle_key_exchange: Actual state : 2
> [3] ssh_handle_key_exchange: Actual state : 2
> [3] Received banner: SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu7
> [1] SSH client banner: SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu7
> [1] Analyzing banner: SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu7
> [1] We are talking to an OpenSSH client version: 5.3 (50300)
> [3] Writing on the wire a packet having 339 bytes before
> [3] 339 bytes after comp + 8 padding bytes = 348 bytes packet
> [3] Enabling POLLOUT for socket
> [3] ssh_handle_key_exchange: Actual state : 4
> [3] ssh_handle_key_exchange: Actual state : 4
> [3] Packet size decrypted: 788 (0x314)
> [3] Read a 788 bytes packet
> [3] 8 bytes padding, 787 bytes left in buffer
> [3] After padding, 779 bytes left in buffer
> [3] Final size 779
> [3] Type 20
> [3] Dispatching handler for packet type 20
> [3] Set output algorithm aes128-ctr
> [3] Set input algorithm aes128-ctr
> [3] ssh_handle_key_exchange: Actual state : 6
> [3] Packet size decrypted: 140 (0x8c)
> [3] Read a 140 bytes packet
> [3] 6 bytes padding, 139 bytes left in buffer
> [3] After padding, 133 bytes left in buffer
> [3] Final size 133
> [3] Type 30
> [3] Dispatching handler for packet type 30
> [3] Received SSH_MSG_KEXDH_INIT
> [1] Invalid state for SSH_MSG_KEXDH_INIT     <-------------- The Error ???
> [3] ssh_handle_key_exchange: Actual state : 6
> [3] ssh_handle_key_exchange: Actual state : 6
> [1] Socket exception callback: 1 (0)                      <------------- Ctrl-C on ssh client.
> [1] Error : Socket error: Success
> [3] ssh_handle_key_exchange: Actual state : 9
> 
> Any clues? 
> other info required?
> 
> 
> Thanks in advance.
> drBob.
> 
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