manager: add hard-coded read checks

The host-client cannot try to read back more than this number of bytes
without hitting a memory overflow in phosphor-host-ipmid.  The method we
can call to dynamically receive that number isn't currently linking out
of the userlayer library.

Note: Once the configure_ac can find and provide the userlayer library
from phosphor-host-ipmid, we can remove the hard-coded 64 and 0xe.

Change-Id: I08f6bb59ce44279f76a494dccaa477ae75d532c4
Signed-off-by: Patrick Venture <venture@google.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/manager.hpp b/manager.hpp
index d7282e6..c0c4249 100644
--- a/manager.hpp
+++ b/manager.hpp
@@ -2,6 +2,7 @@
 
 #include <blobs-ipmid/blobs.hpp>
 #include <ctime>
+#include <host-ipmid/oemrouter.hpp>
 #include <memory>
 #include <string>
 #include <unordered_map>
@@ -10,6 +11,16 @@
 namespace blobs
 {
 
+/* The maximum read size.
+ * NOTE: Once this can be dynamically determined, we'll switch to that method.
+ * Having this in a header allows it to used cleanly for now.
+ */
+const int crcSize = sizeof(uint16_t);
+const int btReplyHdrLen = 5;
+const int btTransportLength = 64;
+const uint32_t maximumReadSize =
+    btTransportLength - (btReplyHdrLen + oem::groupMagicSize + crcSize);
+
 struct SessionInfo
 {
     SessionInfo() = default;