Fix: Delete system routes on shutdown

- Add tun_route_del_all() to delete routes from config
- Use netsh for route deletion on Windows (like add)
- Store route_subnets in UTUN_INSTANCE for cleanup
- Delete routes in utun_instance_destroy() before tun_close()

src/tun_route.c

@@ -158,10 +158,9 @@ int tun_route_add(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
     return ip_route_cmd(ifname, ntohl(network), prefix_len, "add");
 }
 
-int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len) {
-    int ifindex = if_nametoindex(ifname);
+int tun_route_del(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
     if (ifindex == 0) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "Interface %s not found", ifname);
+        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "tun_route_del: ifindex is 0");
         return -1;
     }
 
@@ -173,7 +172,9 @@ int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len) {
     }
 
     // Fallback to ip route command
-    DEBUG_WARN(DEBUG_CATEGORY_TUN, "Netlink failed, trying ip route command for %s", ifname);
+    char ifname[16];
+    snprintf(ifname, sizeof(ifname), "%u", ifindex);
+    DEBUG_WARN(DEBUG_CATEGORY_TUN, "Netlink failed, trying ip route command for ifindex %u", ifindex);
     return ip_route_cmd(ifname, ntohl(network), prefix_len, "del");
 }
 
@@ -247,17 +248,35 @@ int tun_route_add(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
     return 0;
 }
 
-int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len) {
+int tun_route_del(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
+    if (ifindex == 0) {
+        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "tun_route_del: ifindex is 0");
+        return -1;
+    }
+    
+    struct in_addr dest_addr;
+    dest_addr.s_addr = htonl(network);
+    char cmd[256];
+    snprintf(cmd, sizeof(cmd), "netsh interface ip delete route %s/%d interface=%lu store=active",
+             inet_ntoa(dest_addr), prefix_len, (unsigned long)ifindex);
+    int sys_ret = system(cmd);
+    if (sys_ret == 0) {
+        DEBUG_INFO(DEBUG_CATEGORY_TUN, "Deleted route %s/%d via ifindex=%lu", 
+                   inet_ntoa(dest_addr), prefix_len, (unsigned long)ifindex);
+        return 0;
+    }
+    
     MIB_IPFORWARDROW route;
     memset(&route, 0, sizeof(route));
     
     route.dwForwardDest = htonl(network);
     route.dwForwardMask = prefix_to_netmask(prefix_len);
-    route.dwForwardIfIndex = if_nametoindex(ifname);
+    route.dwForwardIfIndex = ifindex;
     
     DWORD ret = DeleteIpForwardEntry(&route);
     if (ret != NO_ERROR) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "Failed to delete route: %lu", ret);
+        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "Failed to delete route %s/%d: %lu", 
+                   inet_ntoa(dest_addr), prefix_len, ret);
         return -1;
     }
     return 0;
@@ -299,6 +318,24 @@ int tun_route_flush(const char *ifname) {
     return 0;
 }
 
+int tun_route_del_all(uint32_t ifindex, struct CFG_ROUTE_ENTRY *routes) {
+    int count = 0;
+    struct CFG_ROUTE_ENTRY *entry = routes;
+    
+    while (entry) {
+        uint32_t network = ntohl(entry->ip.addr.v4.s_addr);
+        if (entry->ip.family == AF_INET) {
+            if (tun_route_del(ifindex, network, entry->netmask) == 0) {
+                count++;
+            }
+        }
+        entry = entry->next;
+    }
+    
+    DEBUG_INFO(DEBUG_CATEGORY_TUN, "Deleted %d routes via ifindex=%lu", count, (unsigned long)ifindex);
+    return count;
+}
+
 #else
 
 // BSD / macOS routing socket implementation
@@ -396,10 +433,9 @@ int tun_route_add(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
     return route_cmd(ifname, network, prefix_len, "add");
 }
 
-int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len) {
-    int ifindex = if_nametoindex(ifname);
+int tun_route_del(uint32_t ifindex, uint32_t network, uint8_t prefix_len) {
     if (ifindex == 0) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "Interface %s not found", ifname);
+        DEBUG_ERROR(DEBUG_CATEGORY_TUN, "tun_route_del: ifindex is 0");
         return -1;
     }
 
@@ -409,7 +445,9 @@ int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len) {
     }
 
     // Fallback to route command
-    DEBUG_WARN(DEBUG_CATEGORY_TUN, "Routing socket failed, trying route command for %s", ifname);
+    char ifname[16];
+    snprintf(ifname, sizeof(ifname), "%u", ifindex);
+    DEBUG_WARN(DEBUG_CATEGORY_TUN, "Routing socket failed, trying route command for ifindex %u", ifindex);
     return route_cmd(ifname, network, prefix_len, "delete");
 }
 

src/tun_route.h

@@ -22,12 +22,20 @@ int tun_route_add(uint32_t ifindex, uint32_t network, uint8_t prefix_len);
 
 /**
  * @brief Delete system route for a subnet via TUN interface
- * @param ifname Interface name (e.g., "tun0")
+ * @param ifindex Interface index
  * @param network Network address in host byte order
  * @param prefix_len Prefix length (1-32)
  * @return 0 on success, -1 on error
  */
-int tun_route_del(const char *ifname, uint32_t network, uint8_t prefix_len);
+int tun_route_del(uint32_t ifindex, uint32_t network, uint8_t prefix_len);
+
+/**
+ * @brief Delete all system routes from config entries
+ * @param ifindex Interface index
+ * @param routes Linked list of route entries to delete
+ * @return Number of routes deleted
+ */
+int tun_route_del_all(uint32_t ifindex, struct CFG_ROUTE_ENTRY *routes);
 
 /**
  * @brief Delete all system routes via specified interface

src/utun_instance.c

@@ -108,6 +108,7 @@ static int instance_init_common(struct UTUN_INSTANCE* instance, struct UASYNC* u
         if (config->route_subnets) {
             int added = tun_route_add_all(instance->tun->ifindex, instance->tun->ifname, config->route_subnets);
             DEBUG_INFO(DEBUG_CATEGORY_TUN, "Added %d system routes for TUN interface", added);
+            instance->route_subnets = config->route_subnets;
         }
     } else {
         DEBUG_INFO(DEBUG_CATEGORY_TUN, "TUN initialization disabled - skipping TUN device setup");
@@ -237,9 +238,11 @@ void utun_instance_destroy(struct UTUN_INSTANCE *instance) {
     if (instance->tun) {
         DEBUG_INFO(DEBUG_CATEGORY_TUN, "Closing TUN interface: %s", instance->tun->ifname);
         
-        // Flush all system routes for this interface
-        tun_route_flush(instance->tun->ifname);
-        DEBUG_INFO(DEBUG_CATEGORY_TUN, "Flushed system routes for %s", instance->tun->ifname);
+        // Delete system routes added at startup
+        if (instance->tun->ifindex && instance->route_subnets) {
+            int deleted = tun_route_del_all(instance->tun->ifindex, instance->route_subnets);
+            DEBUG_INFO(DEBUG_CATEGORY_TUN, "Deleted %d system routes for TUN interface", deleted);
+        }
         
         tun_close(instance->tun);
         instance->tun = NULL;

src/utun_instance.h

@@ -7,6 +7,7 @@
 #include "../lib/memory_pool.h"
 #include "secure_channel.h"
 #include "etcp_api.h"
+#include "config_parser.h"
 
 // Forward declarations
 struct utun_config;
@@ -26,6 +27,9 @@ struct UTUN_INSTANCE {
     
     // TUN interface
     struct tun_if* tun;
+    
+    // Route subnets (for cleanup on shutdown)
+    struct CFG_ROUTE_ENTRY* route_subnets;
 
     struct ROUTE_TABLE* rt;
     struct ROUTE_BGP* bgp;              // BGP module for route exchange