api: add to_net parameter to endian messages

The VPP API auto-generated endian conversion functions are intended to
be symmetrical. They are used both by the API client and the API server.
Called on send to convert from host endian to network endian and on
receive to convert back.

For variable length arrays, we have to iterate over the array and call
a more specific handler for the array type. Unfortunately the length of
the array is part of the api definition, and if it's endian swapped
prior to the for loop, unexpected behaviour will ensue.

There was an earlier fix, for some specific messages, but unfortunately
that only fixed the problem from the VPP (server) side.

This adds a new parameters to the endian handler, so the boundary
argument to the loop can be treated differently depending on if this
message is to the network or from the network.

Type: fix
Change-Id: I43011aed384e3b847579a1dd2c390867ae17a9ad
Signed-off-by: Ole Troan <otroan@employees.org>

1 files changed, 21 insertions, 47 deletions

diff --git a/src/tools/vppapigen/vppapigen_c.py b/src/tools/vppapigen/vppapigen_c.py
index b55066db366..c2e1e7da7b7 100755
--- a/src/tools/vppapigen/vppapigen_c.py
+++ b/src/tools/vppapigen/vppapigen_c.py
@@ -1143,20 +1143,14 @@ ENDIAN_STRINGS = {
 }
 
 
-def get_endian_string(o, type):
+def get_endian_string(o, fieldtype):
     """Return proper endian string conversion function"""
-    try:
-        if o.to_network:
-            return ENDIAN_STRINGS[type].replace("net_to_host", "host_to_net")
-    except:
-        pass
-    return ENDIAN_STRINGS[type]
+    return ENDIAN_STRINGS[fieldtype]
 
 
 def endianfun_array(o):
     """Generate endian functions for arrays"""
     forloop = """\
-    {comment}
     ASSERT((u32){length} <= (u32)VL_API_MAX_ARRAY_SIZE);
     for (i = 0; i < {length}; i++) {{
         a->{name}[i] = {format}(a->{name}[i]);
@@ -1165,31 +1159,26 @@ def endianfun_array(o):
 
     forloop_format = """\
     for (i = 0; i < {length}; i++) {{
-        {type}_endian(&a->{name}[i]);
+        {type}_endian(&a->{name}[i], to_net);
     }}
 """
 
-    to_network_comment = ""
-    try:
-        if o.to_network:
-            to_network_comment = """/*
-     * Array fields processed first to handle variable length arrays and size
-     * field endian conversion in the proper order for to-network messages.
-     * Message fields have been sorted by type in the code generator, thus fields
-     * in this generated code may be converted in a different order than specified
-     * in the *.api file.
-     */"""
-    except:
-        pass
-
     output = ""
     if o.fieldtype == "u8" or o.fieldtype == "string" or o.fieldtype == "bool":
         output += "    /* a->{n} = a->{n} (no-op) */\n".format(n=o.fieldname)
     else:
         lfield = "a->" + o.lengthfield if o.lengthfield else o.length
+        if o.lengthfield:
+            output += (
+                f"    u32 count = to_net ? clib_host_to_net_u32(a->{o.lengthfield}) : "
+                f"a->{o.lengthfield};\n"
+            )
+            lfield = "count"
+        else:
+            lfield = o.length
+
         if o.fieldtype in ENDIAN_STRINGS:
             output += forloop.format(
-                comment=to_network_comment,
                 length=lfield,
                 format=get_endian_string(o, o.fieldtype),
                 name=o.fieldname,
@@ -1222,7 +1211,7 @@ def endianfun_obj(o):
             name=o.fieldname, format=get_endian_string(o, o.fieldtype)
         )
     elif o.fieldtype.startswith("vl_api_"):
-        output += "    {type}_endian(&a->{name});\n".format(
+        output += "    {type}_endian(&a->{name}, to_net);\n".format(
             type=o.fieldtype, name=o.fieldname
         )
     else:
@@ -1254,19 +1243,12 @@ def endianfun(objs, modulename):
     output = output.format(module=modulename)
 
     signature = """\
-static inline void vl_api_{name}_t_endian (vl_api_{name}_t *a)
+static inline void vl_api_{name}_t_endian (vl_api_{name}_t *a, bool to_net)
 {{
     int i __attribute__((unused));
 """
 
     for t in objs:
-        # Outbound (to network) messages are identified by message nomenclature
-        # i.e. message names ending with these suffixes are 'to network'
-        if t.name.endswith("_reply") or t.name.endswith("_details"):
-            t.to_network = True
-        else:
-            t.to_network = False
-
         if t.__class__.__name__ == "Enum" or t.__class__.__name__ == "EnumFlag":
             output += signature.format(name=t.name)
             if t.enumtype in ENDIAN_STRINGS:
@@ -1300,15 +1282,7 @@ static inline void vl_api_{name}_t_endian (vl_api_{name}_t *a)
 
         output += signature.format(name=t.name)
 
-        # For outbound (to network) messages:
-        #   some arrays have dynamic length -- iterate over
-        #   them before changing endianness for the length field
-        #   by making the Array types show up first
-        if t.to_network:
-            t.block.sort(key=lambda x: x.type)
-
         for o in t.block:
-            o.to_network = t.to_network
             output += endianfun_obj(o)
         output += "}\n\n"
 
@@ -1852,7 +1826,7 @@ api_{n} (cJSON *o)
   }}
 
   mp->_vl_msg_id = vac_get_msg_index(VL_API_{N}_CRC);
-  vl_api_{n}_t_endian(mp);
+  vl_api_{n}_t_endian(mp, 1);
   vac_write((char *)mp, len);
   cJSON_free(mp);
 
@@ -1867,7 +1841,7 @@ api_{n} (cJSON *o)
     return 0;
   }}
   vl_api_{r}_t *rmp = (vl_api_{r}_t *)p;
-  vl_api_{r}_t_endian(rmp);
+  vl_api_{r}_t_endian(rmp, 0);
   return vl_api_{r}_t_tojson(rmp);
 }}
 
@@ -1885,7 +1859,7 @@ api_{n} (cJSON *o)
       return 0;
   }}
   mp->_vl_msg_id = msg_id;
-  vl_api_{n}_t_endian(mp);
+  vl_api_{n}_t_endian(mp, 1);
   vac_write((char *)mp, len);
   cJSON_free(mp);
 
@@ -1919,7 +1893,7 @@ api_{n} (cJSON *o)
             return 0;
         }}
         vl_api_{r}_t *rmp = (vl_api_{r}_t *)p;
-        vl_api_{r}_t_endian(rmp);
+        vl_api_{r}_t_endian(rmp, 0);
         cJSON_AddItemToArray(reply, vl_api_{r}_t_tojson(rmp));
     }}
   }}
@@ -1941,7 +1915,7 @@ api_{n} (cJSON *o)
   }}
   mp->_vl_msg_id = msg_id;
 
-  vl_api_{n}_t_endian(mp);
+  vl_api_{n}_t_endian(mp, 1);
   vac_write((char *)mp, len);
   cJSON_free(mp);
 
@@ -1962,14 +1936,14 @@ api_{n} (cJSON *o)
     u16 msg_id = ntohs(*((u16 *)p));
     if (msg_id == reply_msg_id) {{
         vl_api_{r}_t *rmp = (vl_api_{r}_t *)p;
-        vl_api_{r}_t_endian(rmp);
+        vl_api_{r}_t_endian(rmp, 0);
         cJSON_AddItemToArray(reply, vl_api_{r}_t_tojson(rmp));
         break;
     }}
 
     if (msg_id == details_msg_id) {{
         vl_api_{d}_t *rmp = (vl_api_{d}_t *)p;
-        vl_api_{d}_t_endian(rmp);
+        vl_api_{d}_t_endian(rmp, 0);
         cJSON_AddItemToArray(reply, vl_api_{d}_t_tojson(rmp));
     }}
   }}