lib9p: finish refactor

1 files changed, 13 insertions, 26 deletions

diff --git a/lib9p/9p.c b/lib9p/9p.c
index 8633a44..0e71071 100644
--- a/lib9p/9p.c
+++ b/lib9p/9p.c
@@ -36,24 +36,24 @@ int lib9p_errorf(struct lib9p_ctx *ctx, uint32_t linux_errno, char const *fmt, .
 }
 
 ssize_t lib9p_validate(struct lib9p_ctx *ctx, uint8_t *net_bytes) {
-	/* Header */
+	/* Inspect the first 5 bytes ourselves.  */
 	struct _validate_ctx subctx = {
 		.ctx        = ctx,
 		.net_size   = decode_u32le(net_bytes),
 		.net_bytes  = net_bytes,
 
-		.net_offset = 7,
+		.net_offset = 0,
 		.host_extra = 0,
 	};
-	if (subctx.net_size < subctx.net_offset)
-		return lib9p_error(ctx, LINUX_EBADMSG, "message is too short");
+	if (subctx.net_size < 5)
+		return lib9p_error(ctx, LINUX_EBADMSG, "message is impossibly short");
 	uint8_t typ = net_bytes[4];
-
-	/* Body */
 	struct _vtable_msg vtable = _lib9p_vtables[ctx->version].msgs[typ];
 	if (!vtable.validate)
 		return lib9p_errorf(ctx, LINUX_EOPNOTSUPP, "unknown message type: %s (protocol_version=%s)",
 		                    lib9p_msg_type_str(typ), lib9p_version_str(ctx->version));
+
+	/* Now use the message-type-specific vtable to process the whole thing.  */
 	if (vtable.validate(&subctx))
 		return -1;
 	assert(subctx.net_offset <= subctx.net_size);
@@ -61,49 +61,36 @@ ssize_t lib9p_validate(struct lib9p_ctx *ctx, uint8_t *net_bytes) {
 		return lib9p_errorf(ctx, LINUX_EBADMSG, "message has %"PRIu32" extra bytes",
 		                   subctx.net_size - subctx.net_offset);
 
+	/* Return.  */
 	ssize_t ret;
 	if (__builtin_add_overflow(vtable.basesize, subctx.host_extra, &ret))
 		return lib9p_error(ctx, LINUX_EMSGSIZE, "unmarshalled payload overflows SSIZE_MAX");
-
 	return ret;
 }
 
 void lib9p_unmarshal(struct lib9p_ctx *ctx, uint8_t *net_bytes,
-                     enum lib9p_msg_type *ret_typ, uint16_t *ret_tag, void *ret_body) {
-	/* Header */
+                     enum lib9p_msg_type *ret_typ, void *ret_body) {
 	struct _unmarshal_ctx subctx = {
 		.ctx        = ctx,
 		.net_bytes  = net_bytes,
 
-		.net_offset = 7,
+		.net_offset = 0,
 	};
-	*ret_typ = net_bytes[4];
-	*ret_tag = decode_u16le(&net_bytes[5]);
 
-	/* Body */
+	*ret_typ = net_bytes[4];
 	struct _vtable_msg vtable = _lib9p_vtables[ctx->version].msgs[*ret_typ];
 	subctx.extra = ret_body + vtable.basesize;
 	vtable.unmarshal(&subctx, ret_body);
 }
 
-bool lib9p_marshal(struct lib9p_ctx *ctx, enum lib9p_msg_type typ, uint16_t tag, void *body,
+bool lib9p_marshal(struct lib9p_ctx *ctx, enum lib9p_msg_type typ, void *body,
                    uint8_t *ret_bytes) {
-	/* Header */
 	struct _marshal_ctx subctx = {
 		.ctx        = ctx,
 		.net_bytes  = ret_bytes,
-		.net_offset = 7,
+		.net_offset = 0,
 	};
-	ret_bytes[4] = typ;
-	encode_u16le(tag, &ret_bytes[5]);
 
-	/* Body */
 	struct _vtable_msg vtable = _lib9p_vtables[ctx->version].msgs[typ];
-	if (vtable.marshal(&subctx, body))
-		return true;
-
-	/* Header, again */
-	encode_u32le(subctx.net_offset, ret_bytes);
-
-	return false;
+	return vtable.marshal(&subctx, body);
 }