Howto build latest Openvpn for mips64

Download debian wheezy qcow image and kernel

https://people.debian.org/~aurel32/qemu/mips/debian_wheezy_mips_standard.qcow2
https://people.debian.org/~aurel32/qemu/mips/vmlinux-3.2.0-4-5kc-malta

Install qemu-system-mips64

sudo apt install qemu-system-mips 

Start debian wheezy vm inside screen

screen -A -S qemu
qemu-system-mips64 -nographic -M malta -kernel vmlinux-3.2.0-4-5kc-malta -hda debian_wheezy_mips_standard.qcow2 -append "root=/dev/sda1 console=tty0" -net nic -net user,hostfwd=tcp::1810-:22

Access debian wheezy vm

password is root

ssh root@localhost -p 1810

Setup QEMU Build Environment

Compiling requires you to install build-essentials. Debian wheezy has moved to the debian archive so you must update the sources.list Note that you will not be able to authenticate the pacakges from the debian archive due to an expired certificate.

echo "deb [trusted=yes] http://archive.debian.org/debian wheezy main
deb-src [trusted=yes] http://archive.debian.org/debian wheezy main
deb [trusted=yes] http://security.debian.org/ wheezy/updates main
deb-src [trusted=yes] http://security.debian.org/ wheezy/updates main
deb [trusted=yes] http://archive.debian.org/debian wheezy-updates main
deb-src [trusted=yes] http://archive.debian.org/debian wheezy-updates main" > /etc/apt/sources.list

echo "Acquire::Check-Valid-Until false;" > /etc/apt/apt.conf

apt-get update
apt-get install build-essential

Create directories

mkdir ~/src
mkdir ~/build
cd ~/src

Download latest Openssl source and compile it

wget https://www.openssl.org/source/openssl-1.1.1k.tar.gz
tar -xvf openssl-1.1.1k.tar.gz
cd openssl-1.1.1k
./Configure gcc -static -no-shared --prefix=/root/build
make && make install

Download latest LZ4 source and compile it

wget https://github.com/lz4/lz4/archive/v1.9.2.tar.gz
tar -xvf v1.9.2.tar.gz
cd lz4-1.9.2/
make && PREFIX=/root/build make install

Download latest LZO source and compile it

wget https://www.oberhumer.com/opensource/lzo/download/lzo-2.10.tar.gz
tar -xvf lzo-2.10.tar.gz
cd lzo-2.10
./configure --prefix=/root/build --enable-static --target=mips64-linux-gnueabi --host=mips64-linux-gnueabi
make && make install

Download latest Openvpn source and compile it.

wget https://swupdate.openvpn.org/community/releases/openvpn-2.5.1.tar.gz
tar -xvf openvpn-2.5.1.tar.gz
cd openvpn-2.5.1
./configure --prefix=/root/build --enable-static --disable-shared --disable-debug --disable-plugins \
  OPENSSL_CFLAGS="-I/root/build/include" OPENSSL_LIBS="-L/root/build/lib -lssl -lcrypto" LZO_CFLAGS="-I/root/build/include" \
  LZO_LIBS="-L/root/build/lib -llzo2" LZ4_CFLAGS="-I/root/build/include" LZ4_LIBS="-L/root/build/lib -llz4" \
  IFCONFIG=/sbin/ifconfig ROUTE=/sbin/route NETSTAT=/bin/netstat IPROUTE=/sbin/ip --enable-iproute2
make LIBS="-all-static"
make install

openvpn client will be inside ~/build/sbin directory. You can shrink the size of the binary (by around half) if you strip debugging symbols:

strip /root/build/sbin/openvpn