Implement GetPLDMVersion command

This commit implements the GetPLDMVersion which is required
as part of the base PLDM support to know the version of a
given PLDM type.

Change-Id: I1bcbd938c5b6833f62e0ee2f474b04d76b6970d9
Signed-off-by: Sampa Misra <sampmisr@in.ibm.com>
diff --git a/libpldmresponder/base.cpp b/libpldmresponder/base.cpp
index f3bb8f4..9489d47 100644
--- a/libpldmresponder/base.cpp
+++ b/libpldmresponder/base.cpp
@@ -3,6 +3,7 @@
 #include "base.hpp"
 
 #include <array>
+#include <cstring>
 #include <map>
 #include <stdexcept>
 #include <vector>
@@ -17,6 +18,10 @@
 static const std::map<Type, Cmd> capabilities{
     {PLDM_BASE, {PLDM_GET_PLDM_TYPES, PLDM_GET_PLDM_COMMANDS}}};
 
+static const std::map<Type, pldm_version> versions{
+    {PLDM_BASE, {0xF1, 0xF0, 0xF0, 0x00}},
+};
+
 void getPLDMTypes(const pldm_msg_payload* request, pldm_msg* response)
 {
     // DSP0240 has this as a bitfield8[N], where N = 0 to 7
@@ -66,5 +71,36 @@
     encode_get_commands_resp(0, PLDM_SUCCESS, cmds.data(), response);
 }
 
+void getPLDMVersion(const pldm_msg_payload* request, pldm_msg* response)
+{
+    uint32_t transferHandle;
+    Type type;
+    uint8_t transferFlag;
+
+    if (request->payload_length !=
+        (sizeof(transferHandle) + sizeof(type) + sizeof(transferFlag)))
+    {
+        encode_get_version_resp(0, PLDM_ERROR_INVALID_LENGTH, 0, 0, nullptr, 0,
+                                response);
+        return;
+    }
+
+    decode_get_version_req(request, &transferHandle, &transferFlag, &type);
+
+    pldm_version version{};
+    auto search = versions.find(type);
+
+    if (search == versions.end())
+    {
+        encode_get_version_resp(0, PLDM_ERROR_INVALID_PLDM_TYPE, 0, 0, nullptr,
+                                0, response);
+        return;
+    }
+
+    memcpy(&version, &(search->second), sizeof(version));
+    encode_get_version_resp(0, PLDM_SUCCESS, 0, PLDM_START_AND_END, &version,
+                            sizeof(pldm_version), response);
+}
+
 } // namespace responder
 } // namespace pldm