[PATCH net-next 1/3] tools: ynl-gen: support sub-type for binary attributes

[Jakub Kicinski <kuba@kernel.org>]

Sub-type annotation on binary attributes may indicate that the attribute
carries an array of simple types (also referred to as "C array" in docs).
Support rendering them as such in the C user code. For example for u32,
instead of:

  struct {
    u32 arr;
  } _len;

  void *arr;

render:

  struct {
    u32 arr;
  } _count;

  __u32 *arr;

Note that count is the number of elements while len was the length in bytes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 tools/net/ynl/pyynl/ynl_gen_c.py | 56 ++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 10 deletions(-)

diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index 4a2d3cc07e14..2ae5eaf2611d 100755
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -163,7 +163,7 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S
         return False
 
     def _free_lines(self, ri, var, ref):
-        if self.is_multi_val() or self.presence_type() == 'len':
+        if self.is_multi_val() or self.presence_type() in {'count', 'len'}:
             return [f'free({var}->{ref}{self.c_name});']
         return []
 
@@ -516,13 +516,21 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S
 
 class TypeBinary(Type):
     def arg_member(self, ri):
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            return [f'__{self.get("sub-type")} *{self.c_name}', 'size_t count']
         return [f"const void *{self.c_name}", 'size_t len']
 
     def presence_type(self):
-        return 'len'
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            return 'count'
+        else:
+            return 'len'
 
     def struct_member(self, ri):
-        ri.cw.p(f"void *{self.c_name};")
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            ri.cw.p(f'__{self.get("sub-type")} *{self.c_name};')
+        else:
+            ri.cw.p(f"void *{self.c_name};")
 
     def _attr_typol(self):
         return f'.type = YNL_PT_BINARY,'
@@ -549,18 +557,46 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S
         return mem
 
     def attr_put(self, ri, var):
-        self._attr_put_line(ri, var, f"ynl_attr_put(nlh, {self.enum_name}, " +
-                            f"{var}->{self.c_name}, {var}->_len.{self.c_name})")
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            presence = self.presence_type()
+            ri.cw.block_start(line=f"if ({var}->_{presence}.{self.c_name})")
+            ri.cw.p(f"i = {var}->_{presence}.{self.c_name} * sizeof(__{self.get('sub-type')});")
+            ri.cw.p(f"ynl_attr_put(nlh, {self.enum_name}, " +
+                    f"{var}->{self.c_name}, i);")
+            ri.cw.block_end()
+            pass
+        else:
+            self._attr_put_line(ri, var, f"ynl_attr_put(nlh, {self.enum_name}, "
+                                f"{var}->{self.c_name}, {var}->_len.{self.c_name})")
 
     def _attr_get(self, ri, var):
-        len_mem = var + '->_len.' + self.c_name
-        return [f"{len_mem} = len;",
-                f"{var}->{self.c_name} = malloc(len);",
-                f"memcpy({var}->{self.c_name}, ynl_attr_data(attr), len);"], \
+        get_lines = []
+        len_mem = var + '->_' + self.presence_type() + '.' + self.c_name
+
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            get_lines = [
+                f"{len_mem} = len / sizeof(__{self.get('sub-type')});",
+                f"len = {len_mem} * sizeof(__{self.get('sub-type')});",
+            ]
+        else:
+            get_lines += [f"{len_mem} = len;"]
+
+        get_lines += [
+            f"{var}->{self.c_name} = malloc(len);",
+            f"memcpy({var}->{self.c_name}, ynl_attr_data(attr), len);"
+        ]
+
+        return get_lines, \
                ['len = ynl_attr_data_len(attr);'], \
                ['unsigned int len;']
 
     def _setter_lines(self, ri, member, presence):
+        if self.get('sub-type') and self.get('sub-type') in scalars:
+            return [f"{presence} = count;",
+                    f"count *= sizeof(__{self.get('sub-type')});",
+                    f"{member} = malloc(count);",
+                    f'memcpy({member}, {self.c_name}, count);']
+
         return [f"{presence} = len;",
                 f"{member} = malloc({presence});",
                 f'memcpy({member}, {self.c_name}, {presence});']
@@ -672,7 +708,7 @@ from lib import SpecFamily, SpecAttrSet, SpecAttr, SpecOperation, SpecEnumSet, S
         lines = []
         if self.attr['type'] in scalars:
             lines += [f"free({var}->{ref}{self.c_name});"]
-        elif self.attr['type'] == 'binary' and 'struct' in self.attr:
+        elif self.attr['type'] == 'binary':
             lines += [f"free({var}->{ref}{self.c_name});"]
         elif self.attr['type'] == 'string':
             lines += [
-- 
2.49.0