network: configure IPv6 when enabled

If dom0 expose IPv6 address settings, configure it on the interface.
Both backend and frontend side. If no IPv6 configuration is provided,
block IPv6 as it was before.

Fixes QubesOS/qubes-issues#718

network/setup-ip

@@ -7,9 +7,11 @@
 have_qubesdb || exit 0
 
 ip=$(/usr/bin/qubesdb-read /qubes-ip 2> /dev/null)
+ip6=$(/usr/bin/qubesdb-read /qubes-ip6 2> /dev/null)
 if [ "x$ip" != x ]; then
     #netmask=$(/usr/bin/qubesdb-read /qubes-netmask)
     gateway=$(/usr/bin/qubesdb-read /qubes-gateway)
+    gateway6=$(/usr/bin/qubesdb-read /qubes-gateway6)
     primary_dns=$(/usr/bin/qubesdb-read /qubes-primary-dns 2>/dev/null || echo "$gateway")
     secondary_dns=$(/usr/bin/qubesdb-read /qubes-secondary-dns)
     /sbin/ethtool -K "$INTERFACE" sg off
@@ -28,32 +30,72 @@ mac-address=$(ip l show dev "$INTERFACE" |grep link|awk '{print $2}')
 id=VM uplink $INTERFACE
 uuid=de85f79b-8c3d-405f-a652-cb4c10b4f9ef
 type=802-3-ethernet
-
-[ipv6]
-method=ignore
-
+__EOF__
+        ip4_nm_config=""
+        ip6_nm_config=""
+        if ! qsvc disable-dns-server ; then
+            ip4_nm_config="${ip4_nm_config}
+dns=${primary_dns};${secondary_dns}"
+        fi
+        if ! qsvc disable-default-route ; then
+            ip4_nm_config="${ip4_nm_config}
+addresses1=$ip;32;$gateway"
+            if [ -n "$ip6" ]; then
+                ip6_nm_config="${ip6_nm_config}
+addresses1=$ip6;128;$gateway6"
+            fi
+        else
+            ip4_nm_config="${ip4_nm_config}
+addresses1=$ip;32"
+            if [ -n "$ip6" ]; then
+                ip6_nm_config="${ip6_nm_config}
+addresses1=$ip6;128"
+            fi
+        fi
+        if [ -n "$ip4_nm_config" ]; then
+            cat >> "$nm_config" <<__EOF__
 [ipv4]
 method=manual
 may-fail=false
+$ip4_nm_config
+__EOF__
+        else
+            cat >> "$nm_config" <<__EOF__
+[ipv4]
+method=ignore
 __EOF__
-        if ! qsvc disable-dns-server ; then
-            echo "dns=$primary_dns;$secondary_dns" >> "$nm_config"
         fi
-        if ! qsvc disable-default-route ; then
-            echo "addresses1=$ip;32;$gateway" >> "$nm_config"
+
+        if [ -n "$ip6_nm_config" ]; then
+            cat >> "$nm_config" <<__EOF__
+[ipv6]
+method=manual
+may-fail=false
+$ip6_nm_config
+__EOF__
         else
-            echo "addresses1=$ip;32" >> "$nm_config"
+            cat >> "$nm_config" <<__EOF__
+[ipv6]
+method=ignore
+__EOF__
         fi
+
         chmod 600 "$nm_config"
         # reload connection
         nmcli connection load "$nm_config" || :
     else
         # No NetworkManager enabled, configure the network manually
         /sbin/ifconfig "$INTERFACE" "$ip" netmask 255.255.255.255
+        if [ -n "$ip6" ]; then
+            /sbin/ifconfig "$INTERFACE" add "$ip6"/128
+        fi
         /sbin/ifconfig "$INTERFACE" up
         /sbin/route add -host "$gateway" dev "$INTERFACE"
         if ! qsvc disable-default-route ; then
             /sbin/route add default gw "$gateway"
+            if [ -n "$gateway6" ]; then
+                /sbin/route -6 add default gw "$gateway6" dev "$INTERFACE"
+            fi
         fi
         if ! is_protected_file /etc/resolv.conf ; then
             echo > /etc/resolv.conf

network/vif-route-qubes

@@ -29,21 +29,31 @@ lockfile=/var/run/xen-hotplug/vif-lock
 
 # shellcheck disable=SC2154
 if [ "${ip}" ]; then
+    # get first IPv4 and first IPv6
+    for addr in ${ip}; do
+        if [ -z "$ip4" ] && [[ "$addr" = *.* ]]; then
+            ip4="$addr"
+        elif [ -z "$ip6" ] && [[ "$addr" = *:* ]]; then
+            ip6="$addr"
+        fi
+    done
     # IPs as seen by this VM
-    netvm_ip="$ip"
+    netvm_ip="$ip4"
     netvm_gw_ip=$(qubesdb-read /qubes-netvm-gateway)
     netvm_dns1_ip=$(qubesdb-read /qubes-netvm-primary-dns)
     netvm_dns2_ip=$(qubesdb-read /qubes-netvm-secondary-dns)
 
     back_ip="$netvm_gw_ip"
 
     # IPs as seen by the VM - if other than $netvm_ip
-    appvm_gw_ip="$(qubesdb-read "/mapped-ip/$ip/visible-gateway" 2>/dev/null || :)"
-    appvm_ip="$(qubesdb-read "/mapped-ip/$ip/visible-ip" 2>/dev/null || :)"
+    appvm_gw_ip="$(qubesdb-read "/mapped-ip/$ip4/visible-gateway" 2>/dev/null || :)"
+    appvm_ip="$(qubesdb-read "/mapped-ip/$ip4/visible-ip" 2>/dev/null || :)"
 fi
 
 # Apply NAT if IP visible from the VM is different than the "real" one
 # See vif-qubes-nat.sh for details
+# XXX: supported only for the first IPv4 address, IPv6 is dropped if this
+# feature is enabled
 if [ -n "$appvm_ip" ] && [ -n "$appvm_gw_ip" ] && [ "$appvm_ip" != "$netvm_ip" ]; then
     # shellcheck disable=SC2154
     if test "$command" == online; then
@@ -83,9 +93,19 @@ if [ "${ip}" ] ; then
 	# the guest using those addresses.
 	for addr in ${ip} ; do
 		${cmdprefix} ip route "${ipcmd}" "${addr}" dev "${vif}" metric "$metric"
+        if [[ "$addr" = *:* ]]; then
+            ipt=ip6tables-restore
+        else
+            ipt=iptables-restore
+        fi
+        echo -e "*raw\n$iptables_cmd -i ${vif} ! -s ${addr} -j DROP\nCOMMIT" | \
+            ${cmdprefix} flock $lockfile $ipt --noflush
 	done
-	echo -e "*raw\n$iptables_cmd -i ${vif} ! -s ${ip} -j DROP\nCOMMIT" | \
-		${cmdprefix} flock $lockfile iptables-restore --noflush
+    # if no IPv6 is assigned, block all IPv6 traffic on that interface
+    if ! [[ "$ip" = *:* ]]; then
+        echo -e "*raw\n$iptables_cmd -i ${vif} -j DROP\nCOMMIT" | \
+            ${cmdprefix} flock $lockfile ip6tables-restore --noflush
+    fi
 	${cmdprefix} ip addr "${ipcmd}" "${back_ip}/32" dev "${vif}"
 fi