using this as ForceCommand or login shell to forward unix sockets as proxycommand

nc-ssh-proxy.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char **argv) {
	// argv[0]: self
	// argv[1]: -c, coming from ssh
	// argv[2]: actual argument
	// argv[N]: ...
	char buf[80];
	if(argc > 2) {
		snprintf(buf, sizeof(buf), "/tmp/%s.sock", argv[2]);
		return execlp("/bin/nc", "nc", "-U", buf, NULL);
	}
	return printf("one argument required for socketname...\n");
}