tools: ynl-gen: multi-attr: type gen for string

Add support for multi attr strings (needed for link alt_names).
We record the length individual strings in a len member, to do
the same for multi-attr create a struct ynl_string in ynl.h
and use it as a layer holding both the string and its length.
Since strings may be arbitrary length dynamically allocate each
individual one.

Adjust arg_member and struct member to avoid spacing the double
pointers to get "type **name;" rather than "type * *name;"

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250429154704.2613851-8-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/tools/net/ynl/lib/ynl.h b/tools/net/ynl/lib/ynl.h
index 59256e258130..6b8a625aaa5f 100644
--- a/tools/net/ynl/lib/ynl.h
+++ b/tools/net/ynl/lib/ynl.h
@@ -85,6 +85,19 @@ struct ynl_sock {
 	unsigned char raw_buf[];
 };
 
+/**
+ * struct ynl_string - parsed individual string
+ * @len: length of the string (excluding terminating character)
+ * @str: value of the string
+ *
+ * Parsed and nul-terminated string. This struct is only used for arrays of
+ * strings. Non-array string members are placed directly in respective types.
+ */
+struct ynl_string {
+	unsigned int len;
+	char str[];
+};
+
 struct ynl_sock *
 ynl_sock_create(const struct ynl_family *yf, struct ynl_error *e);
 void ynl_sock_destroy(struct ynl_sock *ys);