@@ -2732,40 +2732,105 @@
return ret;
}
+/**
+ * @brief Determines the best route to a destination for both IPv4 and IPv6.
+ *
+ * Uses `GetBestInterfaceEx` and `GetBestRoute2` to find the optimal route
+ * and network interface for the specified destination address.
+ *
+ * @param gc Pointer to struct gc_arena for internal string allocation.
+ * @param dest The destination IP address (IPv4 or IPv6).
+ * @param best_route Pointer to a `MIB_IPFORWARD_ROW2` structure to store the best route.
+ * @return DWORD `NO_ERROR` on success, or an error code.
+ */
+static DWORD
+get_best_route(struct gc_arena *gc, SOCKADDR_INET *dest, MIB_IPFORWARD_ROW2 *best_route)
+{
+ DWORD best_if_index;
+ DWORD status;
+
+ CLEAR(*best_route);
+
+ /* get the best interface index to reach dest */
+ status = GetBestInterfaceEx((struct sockaddr *)dest, &best_if_index);
+ if (status != NO_ERROR)
+ {
+ msg(D_ROUTE, "NOTE: GetBestInterfaceEx returned error: %s (code=%u)",
+ strerror_win32(status, gc),
+ (unsigned int)status);
+ goto done;
+ }
+
+ msg(D_ROUTE_DEBUG, "GetBestInterfaceEx() returned if=%d", (int)best_if_index);
+
+ /* get the routing information (such as NextHop) for the destination and interface */
+ NET_LUID luid;
+ CLEAR(luid);
+ SOCKADDR_INET best_src;
+ CLEAR(best_src);
+ status = GetBestRoute2(&luid, best_if_index, NULL,
+ dest, 0, best_route, &best_src);
+ if (status != NO_ERROR)
+ {
+ msg(D_ROUTE, "NOTE: GetIpForwardEntry2 returned error: %s (code=%u)",
+ strerror_win32(status, gc),
+ (unsigned int)status);
+ goto done;
+ }
+
+done:
+ return status;
+}
+
void
get_default_gateway(struct route_gateway_info *rgi, in_addr_t dest, openvpn_net_ctx_t *ctx)
{
- struct gc_arena gc = gc_new();
-
- const IP_ADAPTER_INFO *adapters = get_adapter_info_list(&gc);
- const MIB_IPFORWARDTABLE *routes = get_windows_routing_table(&gc);
- const MIB_IPFORWARDROW *row = get_default_gateway_row(routes);
- DWORD a_index;
- const IP_ADAPTER_INFO *ai;
-
CLEAR(*rgi);
- if (row)
+ struct gc_arena gc = gc_new();
+
+ /* convert in_addr_t into SOCKADDR_INET */
+ SOCKADDR_INET sa;
+ CLEAR(sa);
+ sa.si_family = AF_INET;
+ sa.Ipv4.sin_addr.s_addr = htonl(dest);
+
+ /* get the best route to the destination */
+ MIB_IPFORWARD_ROW2 best_route;
+ CLEAR(best_route);
+ DWORD status = get_best_route(&gc, &sa, &best_route);
+ if (status != NO_ERROR)
{
- rgi->gateway.addr = ntohl(row->dwForwardNextHop);
- if (rgi->gateway.addr)
+ goto done;
+ }
+
+ rgi->flags = RGI_ADDR_DEFINED | RGI_IFACE_DEFINED;
+ rgi->gateway.addr = ntohl(best_route.NextHop.Ipv4.sin_addr.S_un.S_addr);
+ rgi->adapter_index = best_route.InterfaceIndex;
+
+ if (rgi->gateway.addr == INADDR_ANY)
+ {
+ rgi->flags |= RGI_ON_LINK;
+ }
+
+ /* get netmask and MAC address */
+ const IP_ADAPTER_INFO *adapters = get_adapter_info_list(&gc);
+ const IP_ADAPTER_INFO *ai = get_adapter(adapters, rgi->adapter_index);
+ if (ai)
+ {
+ memcpy(rgi->hwaddr, ai->Address, 6);
+ rgi->flags |= RGI_HWADDR_DEFINED;
+
+ /* get netmask for non-onlink routes */
+ in_addr_t nm = inet_addr(ai->IpAddressList.IpMask.String);
+ if (!(rgi->flags & RGI_ON_LINK) && (nm != INADDR_NONE))
{
- rgi->flags |= RGI_ADDR_DEFINED;
- a_index = adapter_index_of_ip(adapters, rgi->gateway.addr, NULL, &rgi->gateway.netmask);
- if (a_index != TUN_ADAPTER_INDEX_INVALID)
- {
- rgi->adapter_index = a_index;
- rgi->flags |= (RGI_IFACE_DEFINED|RGI_NETMASK_DEFINED);
- ai = get_adapter(adapters, a_index);
- if (ai)
- {
- memcpy(rgi->hwaddr, ai->Address, 6);
- rgi->flags |= RGI_HWADDR_DEFINED;
- }
- }
+ rgi->gateway.netmask = ntohl(nm);
+ rgi->flags |= RGI_NETMASK_DEFINED;
}
}
+done:
gc_free(&gc);
}
@@ -2823,43 +2888,22 @@
const struct in6_addr *dest, openvpn_net_ctx_t *ctx)
{
struct gc_arena gc = gc_new();
- MIB_IPFORWARD_ROW2 BestRoute;
- SOCKADDR_INET DestinationAddress, BestSourceAddress;
- DWORD BestIfIndex;
- DWORD status;
- NET_LUID InterfaceLuid;
-
CLEAR(*rgi6);
- CLEAR(InterfaceLuid); /* cleared = not used for lookup */
- CLEAR(DestinationAddress);
+ SOCKADDR_INET DestinationAddress;
+ CLEAR(DestinationAddress);
DestinationAddress.si_family = AF_INET6;
if (dest)
{
DestinationAddress.Ipv6.sin6_addr = *dest;
}
- status = GetBestInterfaceEx( (struct sockaddr *)&DestinationAddress, &BestIfIndex );
+ MIB_IPFORWARD_ROW2 BestRoute;
+ CLEAR(BestRoute);
+ DWORD status = get_best_route(&gc, &DestinationAddress, &BestRoute);
if (status != NO_ERROR)
{
- msg(D_ROUTE, "NOTE: GetBestInterfaceEx returned error: %s (code=%u)",
- strerror_win32(status, &gc),
- (unsigned int)status);
- goto done;
- }
-
- msg( D_ROUTE, "GetBestInterfaceEx() returned if=%d", (int) BestIfIndex );
-
- status = GetBestRoute2( &InterfaceLuid, BestIfIndex, NULL,
- &DestinationAddress, 0,
- &BestRoute, &BestSourceAddress );
-
- if (status != NO_ERROR)
- {
- msg(D_ROUTE, "NOTE: GetIpForwardEntry2 returned error: %s (code=%u)",
- strerror_win32(status, &gc),
- (unsigned int)status);
goto done;
}
@@ -334,6 +334,13 @@
bool is_special_addr(const char *addr_str);
+/**
+ * @brief Retrieves the best gateway for a given destination based on the routing table.
+ *
+ * @param rgi Pointer to a struct to store the gateway information.
+ * @param dest Destination IP address in host byte order.
+ * @param ctx Pointer to a platform-specific network context struct.
+ */
void get_default_gateway(struct route_gateway_info *rgi,
in_addr_t dest,
openvpn_net_ctx_t *ctx);