diff --git a/src/network/networkd-util.c b/src/network/networkd-util.c
index ce9319d942..bae4ee5cba 100644
--- a/src/network/networkd-util.c
+++ b/src/network/networkd-util.c
@@ -151,3 +151,15 @@ int network_config_section_new(const char *filename, unsigned line, NetworkConfi
 void network_config_section_free(NetworkConfigSection *cs) {
         free(cs);
 }
+
+unsigned hashmap_find_free_section_line(Hashmap *hashmap) {
+        NetworkConfigSection *cs;
+        unsigned n = 0;
+        void *entry;
+
+        HASHMAP_FOREACH_KEY(entry, cs, hashmap)
+                if (n < cs->line)
+                        n = cs->line;
+
+        return n + 1;
+}
diff --git a/src/network/networkd-util.h b/src/network/networkd-util.h
index 2b6541d57e..ce169fa731 100644
--- a/src/network/networkd-util.h
+++ b/src/network/networkd-util.h
@@ -5,7 +5,7 @@
 #include "sd-netlink.h"
 
 #include "conf-parser.h"
-#include "hash-funcs.h"
+#include "hashmap.h"
 #include "log.h"
 #include "macro.h"
 #include "string-util.h"
@@ -52,6 +52,7 @@ int network_config_section_new(const char *filename, unsigned line, NetworkConfi
 void network_config_section_free(NetworkConfigSection *network);
 DEFINE_TRIVIAL_CLEANUP_FUNC(NetworkConfigSection*, network_config_section_free);
 extern const struct hash_ops network_config_hash_ops;
+unsigned hashmap_find_free_section_line(Hashmap *hashmap);
 
 static inline bool section_is_invalid(NetworkConfigSection *section) {
         /* If this returns false, then it does _not_ mean the section is valid. */