New SFTP plugin available now

[JOUBE]

Maybe try just enter the openssh agent in a pageant.lnk (in the plugin folder)?

[gpant]

Maybe try just enter the openssh agent in a pageant.lnk (in the plugin folder)?

I am sorry I don't understand what you mean exactly ?

[JOUBE]

sftpplug.rc:

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    IDS_AGENT_CONNECTERROR  "Failure connecting to ssh-agent (Pageant)!\nYou can put a link file named pageant.lnk in the plugin directory to launch pageant, e.g. pointing to\nc:\\path\\pageant.exe keyfilename"

[gpant]

sftpplug.rc:

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    IDS_AGENT_CONNECTERROR  "Failure connecting to ssh-agent (Pageant)!\nYou can put a link file named pageant.lnk in the plugin directory to launch pageant, e.g. pointing to\nc:\\path\\pageant.exe keyfilename"

An ssh agent is a service listening to a local socket for requests over a specific protocol (defined here https://datatracker.ietf.org/doc/html/draft-miller-ssh-agent-11), you cant just replace pageant with it.

You can use clients to interact with it, for example you could use the ssh-add.exe tool to inquire for keys as well as add keys to the agent etc, but that would still not help the integration with TC

Edit: A nice explanation here: https://smallstep.com/blog/ssh-agent-explained/

[JOUBE]

An ssh agent is a service listening to a local socket for requests over a specific protocol

Yes. You can substitute Pageant with Openssh agent. And Tc uses the standard requests of the lib.

[gpant]

Ok after checking how pageant works they use the same protocol, I will check tomorrow if I can sign a message successfully by just replacing the pipe from the ssh-agent to the pageant one on a test app, if that works then it would be as easy as TC checking the sshd_config for the pipe used by the agent and using that.

[ghisler(Author)]

My plugin uses libssh2_agent_init to create the Agent object, and then libssh2_agent_connect to connect to it. According to "supported_backends" in agent.c it supports the backends Pageant, OpenSSH and Unix. So in principle it should work with the OpenSSH backend...

[gpant]

Ok, so since libssh2 1.10.0, will read the env and use the windows pipe of openssh-agent instead of trying to access the pageant af_unix socket ! it works as long as you dont have a borked env variable. So it does work as it should.
No change needed other than the checkbox string to either include openssh or just rename to "Use ssh-Agent"

[JOUBE]

So it does work as it should. No change needed ...

As I said:

Yes. You can substitute Pageant with Openssh agent. And Tc uses the standard requests of the lib.

and

... other than the checkbox string to either include openssh or just rename to "Use ssh-Agent"

... really a minor issue, for which microsoft windows needed 20 years to implement it.

Joube

[JOUBE]

largefilesupport=1

Interesting.

This is apparently an option with/of libssh2. Could you please document this and all other options from sftpplug.ini, because I didn't find anything about it in this Tc-forum or in the SFTP-plugin. For example - the easiest way - is within the readme.txt, that comes with the plugin.

[ghisler(Author)]

No, it's a plugin option. You can find the implementation in the sources of my plugin. In short, it sends the shell command
file `which scp`
and receives a reply like this:

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/usr/bin/scp: ELF 32-bit LSB shared object, ARM, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.26, BuildID[sha1]=0xf079a239b6c061e8213eb39609a13240dbf5f333, stripped

or this:

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/usr/bin/scp: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=a83ad5fb43e27b41a78575121e25f6ba382b6104, stripped

In my tests, only the 64-bit version was reliably capable of handling files >2GB. Maybe it was changed in a newer version of scp, but TC warns the user when 64-bit isn't reported.

You can send the command
file `which scp`
yourself via the Total Commander command line to the plugin. Double click on the 2 line command history to be able to copy the result.

[CoolWater]

I made some further tests and did some research. Unfortunately libssh2 seems to be the slowest of all open-source SSH/SFTP/SCP implementations.

Libssh, FileZilla and WinSCP are way faster than libssh2. FileZilla and WinSCP are Putty-based.

The only downside of using libssh would be that it doesn't support WinCNG (Windows crypto API).

Here is a comparison between libssh and libssh2:
https://libssh2.org/libssh2-vs-libssh.html

Side-fact: According to OpenSSH developers in April 2019, SCP is outdated, inflexible and not readily fixed; they recommend the use of more modern protocols like SFTP and rsync for file transfer.

Maybe supporting rsync would be a good option to be implemented.

[ghisler(Author)]

There is a third party Putty based plugin:
https://totalcmd.net/plugring/sftp4tc.html
Unfortunately it hasn't been updated since 2017.

[JOUBE]

For testing, I made some changes concerning the buffer sizes. They are now dynamically calculated. Here are my results:
Download speed before:
SFTP: ~7.7 MB/s
Download speed with dynamic buffers:
SFTP: ~20 MB/s

Upload speed before:
SFTP: ~2.7 MB/s
Upload speed with dynamic buffers:
SFTP: ~5.3 MB/s

I made some further tests and did some research. Unfortunately libssh2 seems to be the slowest of all open-source SSH/SFTP/SCP implementations.

@ghisler(author)
As Coolwater writes in his tests, dynamic buffers speed up uploads/downloads. So don't worry about what others say about libssh2 and what might be true. Please implement dynamic buffer to speed up the plugin 3 times now. That's enough for now.

Thanks in advance and best regards

Joube

[ghisler(Author)]

He sent me his changes but there are several problems with them which need to be addressed first:
- crashes in text mode
- strange choice of buffer size, seems to converge to 32 seconds(!) per buffer with no upper buffer size limit
- use of goto commands, a no-go according to all teachers.