two-way sync; from firewalled host

I have two hosts, host C which is firewalled (no sshd), and host S which has sshd and is not firewalled. Both have clone of the same repo, modified locally and differently on both hosts.

I need to two-way sync them by running commands on C (the firewalled one).

I need a script that does it, the "git-sync" script, running on C.
              git-sync  user@host:path  [local-dir]   # synchronize
local repo with
                                                                   #
remote repo via ssh
If there are no conflicts, I need to bring both repos to same state (even if
their history will be different). If there are conflicts, I need to
synchronize everything
that is not in conflict, and report the list of conflicted files, and leave
the remote version as  './file.SUFFIX'  on host C, where script was invoked.

Thanks Yakov