I have installed the lates trunk - r43322 - onto my TP-Link WDR4300 router.

I tried to install luci-app-openvpn. But I could not install it due to some dependency problem:

opkg install luci-app-openvpn
Installing luci-app-openvpn (git-14.321.51707-f81be49-1) to root...
Downloading http://downloads.openwrt.org/snapshots/ … r71xx.ipk.
Collected errors:
* satisfy_dependencies_for: Cannot satisfy the following dependencies for luci-app-openvpn:
*      openvpn *
* opkg_install_cmd: Cannot install package luci-app-openvpn.

I checked openvpn packages are installed:

openssl-util - 1.0.1j-3
openvpn-easy-rsa - 2013-01-30-2
openvpn-nossl - 2.3.4-1
openvpn-openssl - 2.3.4-1
openvpn-polarssl - 2.3.4-1

What else should I install?

As I see luci-app-openvpn depends on the below packages:

opkg depends -A luci-app-openvpn
luci-app-openvpn depends on:
        libc
        openvpn

Any idea?

luci-app-openvpn is broken, has been for quite some time. I'm afraid you need to resort to command-line configuration.

https://github.com/openwrt/luci/tree/ma … ci-openvpn

its available again - you should report bugs there at the issue tracker