SVN-SSH Tunnel via 3rd machine?

I have a client that has SVN+SSH set up that I need to access. Unfortunately I can't get my IP white-listed because I'm on Comcast and they ha开发者_运维知识库ve some security policy against that. I do, however, have SSH access to another machine that I can SSH into that can also SSH into the SVN server (via a non-standard port)... So the total loop needs to look like:

Local Computer (OSX)  --SSH-->  Server1  --SVN+SSH_4567-->  SVN Server

I know how to set up basic SSH tunnels, but I'm not sure how to set this up, or if it's even possible. Help? :)

Note that ideally, I can set this up somehow in ~/.ssh/config and ~/.subversion/config and not have to manually tunnel from A->B->C each time I want to make a commit/update

ssh -L 1234:svnserver:4567 server1

The tunneled connection will be

ssh -p 1234 localhost

To automate this somewhat you can add the tunnel connection to ~/.subversion/config:

[tunnels]
tssh = ssh -p 1234

and then use svn+tssh://localhost/path/to/repo but I don't know of a way to automate creating the tunnel.

Open SSH session to Server1 and setup tunneling in that session:

ssh server1 -L 9000:127.0.0.1:svnserver:22

PS. You might want to check the ssh man page for syntax. I don't remember the correct flags to open a tunnel.

And then locally, you connect to the server using svn+ssh://localhost:9000