[TCPIP] Rearrange LwIP glue code.

Reduce unnecessary stuff in LwIP itself.

drivers/network/tcpip/ip/lwip_glue/memory.c

@@ -0,0 +1,63 @@
+#include <lwip/mem.h>
+
+#ifndef LWIP_TAG
+    #define LWIP_TAG 'PIwl'
+#endif
+
+void *
+malloc(mem_size_t size)
+{
+    return ExAllocatePoolWithTag(NonPagedPool, size, LWIP_TAG);
+}
+
+void *
+calloc(mem_size_t count, mem_size_t size)
+{
+    void *mem = malloc(count * size);
+
+    if (!mem) return NULL;
+
+    RtlZeroMemory(mem, count * size);
+
+    return mem;
+}
+
+void
+free(void *mem)
+{
+    ExFreePoolWithTag(mem, LWIP_TAG);
+}
+
+/* This is only used to trim in lwIP */
+void *
+realloc(void *mem, size_t size)
+{
+    void* new_mem;
+
+    /* realloc() with a NULL mem pointer acts like a call to malloc() */
+    if (mem == NULL) {
+        return malloc(size);
+    }
+
+    /* realloc() with a size 0 acts like a call to free() */
+    if (size == 0) {
+        free(mem);
+        return NULL;
+    }
+
+    /* Allocate the new buffer first */
+    new_mem = malloc(size);
+    if (new_mem == NULL) {
+        /* The old buffer is still intact */
+        return NULL;
+    }
+
+    /* Copy the data over */
+    RtlCopyMemory(new_mem, mem, size);
+
+    /* Deallocate the old buffer */
+    free(mem);
+
+    /* Return the newly allocated block */
+    return new_mem;
+}