MdeModulePkg/Network: Add 32bit subnet mask support for IP4 PXE boot.

[mirror_edk2.git] / MdeModulePkg / Universal / Network / Ip4Dxe / Ip4Route.c

diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Route.c b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Route.c
index d240d5343aea366a3f0acab82ef73f09724114e6..120345836b4ca96aac5446889553a7410c67f195 100644 (file)
--- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Route.c
+++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Route.c
@@ -494,6 +494,11 @@ Ip4FindRouteEntry (
   @param[in]  RtTable               The route table to search from\r
   @param[in]  Dest                  The destination address to search for\r
   @param[in]  Src                   The source address to search for\r
+  @param[in]  SubnetMask            The subnet mask of the Src address, this field is\r
+                                    used to check if the station is using /32 subnet.\r
+  @param[in]  AlwaysTryDestAddr     Always try to use the dest address as next hop even\r
+                                    though we can't find a matching route entry. This\r
+                                    field is only valid when using /32 subnet.\r
 \r
   @return NULL if failed to route packet, otherwise a route cache\r
           entry that can be used to route packet.\r
@@ -503,7 +508,9 @@ IP4_ROUTE_CACHE_ENTRY *
 Ip4Route (\r
   IN IP4_ROUTE_TABLE        *RtTable,\r
   IN IP4_ADDR               Dest,\r
-  IN IP4_ADDR               Src\r
+  IN IP4_ADDR               Src,\r
+  IN IP4_ADDR               SubnetMask,\r
+  IN BOOLEAN                AlwaysTryDestAddr\r
   )\r
 {\r
   LIST_ENTRY                *Head;\r
@@ -535,7 +542,11 @@ Ip4Route (
   RtEntry = Ip4FindRouteEntry (RtTable, Dest);\r
 \r
   if (RtEntry == NULL) {\r
-    return NULL;\r
+    if (SubnetMask != IP4_ALLONE_ADDRESS) {\r
+      return NULL;\r
+    } else if (!AlwaysTryDestAddr) {\r
+      return NULL;\r
+    }\r
   }\r
 \r
   //\r
@@ -544,16 +555,23 @@ Ip4Route (
   // network. Otherwise, it is an indirect route, the packet will be\r
   // sent to the next hop router.\r
   //\r
-  if ((RtEntry->Flag & IP4_DIRECT_ROUTE) != 0) {\r
+  // When using /32 subnet mask, the packet will always be sent to the direct\r
+  // destination first, if we can't find a matching route cache.\r
+  //\r
+  if (SubnetMask == IP4_ALLONE_ADDRESS || ((RtEntry->Flag & IP4_DIRECT_ROUTE) != 0)) {\r
     NextHop = Dest;\r
   } else {\r
     NextHop = RtEntry->NextHop;\r
   }\r
 \r
-  Ip4FreeRouteEntry (RtEntry);\r
+  if (RtEntry != NULL) {\r
+    Ip4FreeRouteEntry (RtEntry);\r
+  }\r
 \r
   //\r
   // Create a route cache entry, and tag it as spawned from this route entry\r
+  // For /32 subnet mask, the default route in RtEntry will be used if failed\r
+  // to send the packet to driect destination address.\r
   //\r
   RtCacheEntry = Ip4CreateRouteCacheEntry (Dest, Src, NextHop, (UINTN) RtEntry);\r
 \r