1 files changed, 74 insertions, 0 deletions
diff --git a/lib9p/defs.h b/lib9p/defs.h
new file mode 100644
index 0000000..907cdde
--- /dev/null
+++ b/lib9p/defs.h
@@ -0,0 +1,74 @@
+/* 9p/defs.h - TODO
+ *
+ * Copyright (C) 2024  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _9P_DEFS_H_
+#define _9P_DEFS_H_
+
+#include <stdint.h>
+
+#define P9_NOTAG ((uint16_t)~0U)
+#define P9_NOFID ((uint32_t)~0U)
+
+enum p9_version {
+	P9_VER_UNINITIALIZED,
+	/* P9_VER_9P1, */
+	P9_VER_9P2000,
+	/*P9_VER_9P2000_u,*/
+	/*P9_VER_9P2000_L,*/
+	/*P9_VER_9P2000_e,*/
+	_P9_VER_CNT,
+};
+
+struct p9_ctx;
+
+enum p9_version p9_ctx_version(p9_ctx *);
+
+/** Write an static error into ctx, return -1.  */
+int p9_error(struct p9_ctx *ctx, uint32_t linux_errno, char const *msg);
+/** Write a printf-style error into ctx, return -1.  */
+int p9_errorf(struct p9_ctx *ctx, uint32_t linux_errno, char const *fmt, ...);
+
+/**
+ * Return how much space the message at net_bytes will take when
+ * unmarshaled.  This number may be larger than net_bytes due to (1)
+ * struct padding, (2) nul-terminator byes for strings.
+ *
+ * Emits an error (return -1, set ctx->err_num and ctx->err_msg) if
+ * either the message type is unknown or if net_bytes is too short for
+ * that message type.
+ *
+ * @param net_bytes : the complete request, starting with the "size[4]"
+ * @return required size, or -1 on error
+ */
+size_t p9_unmarshal_size(struct p9_ctx *ctx, uint8_t *net_bytes);
+
+/**
+ * Unmarshal the 9P message `net_bytes` into the C struct `out_body`.
+ *
+ * Emits an error (return 0, set ctx->err_num and ctx->err_msg) if a
+ * string contains invalid UTF-8 or a nul-byte.
+ *
+ * @param net_bytes : the complete message, starting with the "size[4]"
+ * @param out_tag : the message-ID tag
+ * @param out_body : the message body, must be at least p9_unmarshal_size() bytes
+ * @return the message type, or -1 on error
+ */
+uint8_t p9_unmarshal(struct p9_ctx *ctx, uint8_t *net_bytes, uint16_t *out_tag, void *out_body);
+
+/**
+ * Marshal a `struct p9_msg_{type}` structure into a byte-array.  
+ *
+ * @param struct p9_ctx *ctx : a request context
+ * @param uint16_t  msgid : the message-ID tag
+ * @param struct p9_msg_{type}  msg : the message to encode
+ *
+ * @param uint8_t  *out_bytes : the buffer to encode to, must be at be at least ctx->max_msg_size bytes
+ * @return uint32_t : the encoded length, or -1 on error
+ */
+#define p9_marshal(ctx, msgid, msg, out_bytes) _p9_marshal(ctx, P9_TYPECODE_FOR_CTYPE(msg), msgid, &(msg), out_bytes)
+uint32_t _p9_marshal(struct p9_ctx *ctx, uint8_t typ, uint16_t msgid, void *body, uint8_t *out_bytes);
+
+#endif /* _9P_DEFS_H_ */