Define new CONST_TO_*_CONN() functions for const-to-const casts

These names are analogous to the CONST_TO_*_CIRC() functions we have
for circuits.

Part of #40046.

2 files changed, 14 insertions, 0 deletions

diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c
index 216aeb68d1..20e38ac44b 100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@ -233,6 +233,18 @@ TO_LISTENER_CONN(connection_t *c)
   return DOWNCAST(listener_connection_t, c);
 }
 
+/**
+ * Cast a `const connection_t *` to a `const listener_connection_t *`.
+ *
+ * Exit with an assertion failure if the input is not a
+ * `listener_connection_t`.
+ **/
+const listener_connection_t *
+CONST_TO_LISTENER_CONN(const connection_t *c)
+{
+  return TO_LISTENER_CONN((connection_t *)c);
+}
+
 size_t
 connection_get_inbuf_len(connection_t *conn)
 {
diff --git a/src/core/mainloop/connection.h b/src/core/mainloop/connection.h
index af45007676..ee3dce49f4 100644
--- a/src/core/mainloop/connection.h
+++ b/src/core/mainloop/connection.h
@@ -31,6 +31,8 @@ struct tor_addr_t;
 struct or_options_t;
 
 struct listener_connection_t *TO_LISTENER_CONN(struct connection_t *);
+const struct listener_connection_t *CONST_TO_LISTENER_CONN(
+                                      const struct connection_t *);
 
 struct buf_t;