[nat64] fix tayga start (#177)

diff --git a/.travis/before_install.sh b/.travis/before_install.sh
index 8372e15..aeabaaf 100755
--- a/.travis/before_install.sh
+++ b/.travis/before_install.sh
@@ -58,6 +58,9 @@
             make && sudo make install) || die 'Failed to build OpenThread!'
         which ot-ncp-ftd || die 'Unable to find ot-ncp-ftd!'
         sudo apt-get install socat
+        echo 0 | sudo tee /proc/sys/net/ipv6/conf/all/disable_ipv6
+        echo 1 | sudo tee /proc/sys/net/ipv6/conf/all/forwarding
+        echo 1 | sudo tee /proc/sys/net/ipv4/conf/all/forwarding
         # Skip installing build dependencies when checking script
         exit 0
     }
diff --git a/.travis/script.sh b/.travis/script.sh
index 795d01d..f4e087e 100755
--- a/.travis/script.sh
+++ b/.travis/script.sh
@@ -75,7 +75,7 @@
 script-check)
     RELEASE=1 ./script/bootstrap || die 'Failed to bootstrap for release!'
     ./script/bootstrap || die 'Failed to bootstrap for development!'
-    ./script/setup || die 'Failed to setup!'
+    NAT64=1 ./script/setup || die 'Failed to setup!'
     SOCAT_OUTPUT=/tmp/ot-socat
 
     socat -d -d pty,raw,echo=0 pty,raw,echo=0 > /dev/null 2> $SOCAT_OUTPUT &
@@ -95,14 +95,17 @@
 
     ot-ncp-ftd 1 > $DEVICE_PTY < $DEVICE_PTY &
     ./script/console & SERVICES_PID=$!
+    sudo service tayga start
     echo 'Waiting for services to be ready...'
     sleep 10
     netstat -an | grep 49191 || die 'Service otbr-agent not ready!'
     netstat -an | grep 80 || die 'Service otbr-web not ready!'
+    pidof tayga || die 'tayga not running'
     kill $SERVICES_PID || die 'Failed to stop services!'
     sudo killall otbr-web || true
     sudo killall otbr-agent || true
     sudo killall wpantund || true
+    sudo service tayga stop || true
     killall ot-ncp-ftd || die 'Failed to end OpenThread!'
     killall socat || die 'Failed to end socat!'
     jobs
diff --git a/script/_nat64 b/script/_nat64
index 4a5c8e5..465313b 100644
--- a/script/_nat64
+++ b/script/_nat64
@@ -33,6 +33,8 @@
 TAYGA_DEFAULT=/etc/default/tayga
 TAYGA_CONF=/etc/tayga.conf
 TAYGA_IPV4_ADDR=192.168.255.1
+TAYGA_IPV6_ADDR=fdaa:bb:1::1
+TAYGA_TUN_V6_ADDR=fdaa:bb:1::2
 NAT44_SERVICE=/etc/init.d/otbr-nat44
 WLAN_IFNAMES=eth0
 
@@ -47,8 +49,10 @@
     test -f $TAYGA_DEFAULT -a -f $TAYGA_CONF || die 'Cannot find tayga configuration file!'
     sudo sed -i 's/^RUN="no"/RUN="yes"/' $TAYGA_DEFAULT
     sudo sed -i 's/^IPV4_TUN_ADDR=""/IPV4_TUN_ADDR="'$TAYGA_IPV4_ADDR'"/' $TAYGA_DEFAULT
+    sudo sed -i 's/^IPV6_TUN_ADDR=""/IPV6_TUN_ADDR="'$TAYGA_TUN_V6_ADDR'"/' $TAYGA_DEFAULT
     sudo sed -i 's/^prefix /##prefix /' $TAYGA_CONF
     sudo sed -i 's/^# prefix 64:ff9b::\/96/prefix 64:ff9b::\/96/' $TAYGA_CONF
+    sudo sed -i '/^#ipv6-addr/a ipv6-addr '$TAYGA_IPV6_ADDR $TAYGA_CONF
     sudo tee $NAT44_SERVICE <<EOF
 #! /bin/sh
 #
@@ -131,6 +135,7 @@
     sudo sed -i 's/^IPV4_TUN_ADDR="'$TAYGA_IPV4_ADDR'"/IPV4_TUN_ADDR=""/' $TAYGA_DEFAULT
     sudo sed -i 's/^prefix 64:ff9b::\/96/# prefix 64:ff9b::\/96/' $TAYGA_CONF
     sudo sed -i 's/^##prefix /prefix /' $TAYGA_CONF
+    sudo sed -i '/^ipv6-addr '$TAYGA_IPV6_ADDR'/d' $TAYGA_CONF
 
     if have systemctl; then
         sudo systemctl disable otbr-nat44 || true