jvs/jvs-bus.c: Add JVS bus definitions

jvs/jvs-bus.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "hook/iobuf.h"
+
+struct jvs_node {
+    struct jvs_node *next;
+    void (*transact)(
+            struct jvs_node *node,
+            const void *bytes,
+            size_t nbytes,
+            struct iobuf *resp);
+    bool (*sense)(struct jvs_node *node);
+};
+
+void jvs_bus_transact(
+        struct jvs_node *head,
+        const void *bytes,
+        size_t nbytes,
+        struct iobuf *resp);
+
+bool jvs_node_sense(struct jvs_node *node);