Allow custom routes inside UPF

This is required to work around liveness failure in a single interface
machine where Kubelet node IP is part of eNB subnet.

Change-Id: I37549d89fbe7e045e6639295c29652ba0d6fb5e4
diff --git a/bess-upf/templates/statefulset-upf.yaml b/bess-upf/templates/statefulset-upf.yaml
index 8816359..3786a89 100644
--- a/bess-upf/templates/statefulset-upf.yaml
+++ b/bess-upf/templates/statefulset-upf.yaml
@@ -61,6 +61,9 @@
         args:
         - ip route replace {{ .Values.config.upf.enb.subnet }} via {{ .Values.config.upf.access.gateway }};
           ip route replace default via {{ .Values.config.upf.core.gateway }} metric 110;
+          {{- range .Values.config.upf.routes }}
+          ip route replace {{ .to }} via {{ .via }};
+          {{- end }}
           iptables -I OUTPUT -p icmp --icmp-type port-unreachable -j DROP;
         securityContext:
           capabilities: