token-validator: fix IP assignation when > 254 (there is a lot of student this year)

token-validator/students.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
+	"net"
 	"strings"
 
 	"github.com/julienschmidt/httprouter"
@@ -89,7 +90,7 @@ func createStudent(_ httprouter.Params, body []byte) (interface{}, error) {
 	}
 	exist.RegisterAccess(std.IP, std.MAC)
 
-	ip := fmt.Sprintf("172.23.0.%d", IPSuffix(exist))
+	ip := IPSuffix(exist, net.IPNet{net.ParseIP("172.23.0.0"), net.CIDRMask(17, 32)}).String()
 	exist.IP = &ip
 
 	return exist, nil