add network utilities for CIDR normalization and validation

wireguard_tools/networks.py

@@ -0,0 +1,42 @@
+import ipaddress
+
+
+def normalize_cidr_list(cidr_list):
+    """
+    Receives a list of strings like ['10.0.0.1/24', '10.0.0.0/24'].
+    Returns a sorted unique list of canonical CIDRs (strict=False).
+    Invalid items are ignored.
+    """
+    normalized = set()
+    for item in cidr_list or []:
+        if not item:
+            continue
+        try:
+            normalized.add(str(ipaddress.ip_network(item, strict=False)))
+        except Exception:
+            continue
+    return sorted(normalized)
+
+
+def normalize_cidr_pairs(ip_netmask_pairs):
+    """
+    Receives an iterable of (ip, netmask) pairs and returns a sorted unique list
+    of canonical CIDRs (strict=False). Invalid items are ignored.
+    """
+    cidrs = []
+    for ip, netmask in ip_netmask_pairs or []:
+        if ip is None or netmask is None:
+            continue
+        cidrs.append(f"{ip}/{netmask}")
+    return normalize_cidr_list(cidrs)
+
+
+def safe_network_cidr(address, netmask):
+    """
+    Returns the network CIDR for an address/netmask, or None if invalid.
+    """
+    try:
+        network = ipaddress.ip_network(f"{address}/{netmask}", strict=False)
+        return str(network)
+    except Exception:
+        return None