Alternative method scan subnet

SRV/services/subnet_service.py

@@ -433,6 +433,65 @@ class SubnetService:
             logger.warning(f"Failed to determine interface: {str(e)}, defaulting to eth0")
             return "eth0"
 
+    def _get_prefix_from_ip_cmd(self, iface: str) -> Optional[int]:
+        """Пытается получить префикс подсети из вывода `ip addr`, если netifaces дал неточную маску."""
+        try:
+            result = subprocess.run(
+                ["ip", "-o", "-f", "inet", "addr", "show", "dev", iface],
+                capture_output=True,
+                text=True,
+                check=False,
+                timeout=2,
+            )
+            if result.returncode != 0 or not result.stdout:
+                return None
+            # пример строки: "3: wlp0s20f3    inet 10.1.1.31/24 brd 10.1.1.255 scope global dynamic noprefixroute wlp0s20f3"
+            for part in result.stdout.split():
+                if "/" in part and part.count(".") == 3:
+                    try:
+                        return int(part.split("/")[1])
+                    except ValueError:
+                        continue
+            return None
+        except Exception as e:
+            logger.debug(f"ip addr prefix detection failed for {iface}: {e}")
+            return None
+
+    def _get_prefix_from_proc_route(self, iface: str) -> Optional[int]:
+        """Читает маску для интерфейса из /proc/net/route (не требует прав netlink)."""
+        try:
+            with open("/proc/net/route") as f:
+                for line in f:
+                    parts = line.strip().split()
+                    if len(parts) < 8 or parts[0] != iface:
+                        continue
+                    mask_hex = parts[7]
+                    try:
+                        mask_int = int(mask_hex, 16)
+                    except ValueError:
+                        continue
+                    # mask_int в host byte order, например FF000000 для 255.0.0.0
+                    mask_str = socket.inet_ntoa(mask_int.to_bytes(4, byteorder="little"))
+                    return ipaddress.ip_network(f"0.0.0.0/{mask_str}", strict=False).prefixlen
+            return None
+        except Exception as e:
+            logger.debug(f"/proc/net/route prefix detection failed for {iface}: {e}")
+            return None
+
+    def _get_prefix_from_broadcast(self, ip: str, broadcast: Optional[str]) -> Optional[int]:
+        """Вычисляет префикс из пары IP + broadcast, если она присутствует (часто точнее для 10.x)."""
+        if not ip or not broadcast:
+            return None
+        try:
+            ip_int = int(ipaddress.IPv4Address(ip))
+            bcast_int = int(ipaddress.IPv4Address(broadcast))
+            mask_int = ~(ip_int ^ bcast_int) & 0xFFFFFFFF
+            mask = ipaddress.ip_network(f"0.0.0.0/{ipaddress.IPv4Address(mask_int)}", strict=False).prefixlen
+            return mask
+        except Exception as e:
+            logger.debug(f"Broadcast-based prefix detection failed for {ip}/{broadcast}: {e}")
+            return None
+
     def _get_default_subnet(self) -> str:
         """Автоматически определяет подсеть локального устройства.
 
@@ -454,8 +513,15 @@ class SubnetService:
                     ip_info = addrs[netifaces.AF_INET][0]
                     ip = ip_info["addr"]
                     netmask = ip_info["netmask"]
-                    # Преобразуем маску из строки (например, "255.255.255.0") в CIDR
-                    mask = ipaddress.ip_network(f"0.0.0.0/{netmask}", strict=False).prefixlen
+                    broadcast = ip_info.get("broadcast")
+                    # netifaces иногда отдаёт неточную маску (например, 255.0.0.0 для 10.x),
+                    # пробуем уточнить через `ip addr`, затем /proc/net/route, затем по broadcast, и только потом берём netmask.
+                    mask = (
+                        self._get_prefix_from_ip_cmd(iface)
+                        or self._get_prefix_from_proc_route(iface)
+                        or self._get_prefix_from_broadcast(ip, broadcast)
+                        or ipaddress.ip_network(f"0.0.0.0/{netmask}", strict=False).prefixlen
+                    )
                     network = ipaddress.ip_network(f"{ip}/{mask}", strict=False)
                     logger.info(f"Auto-detected subnet: {network} (IP: {ip}, Mask: {netmask} -> /{mask})")
                     return str(network)