+static inline int dccp_feat_is_valid_length(u8 type, u8 feature, u8 len)
+{
+ /* sec. 6.1: Confirm has at least length 3,
+ * sec. 6.2: Change has at least length 4 */
+ if (len < 3)
+ return 1;
+ if (len < 4 && (type == DCCPO_CHANGE_L || type == DCCPO_CHANGE_R))
+ return 1;
+ /* XXX: add per-feature length validation (sec. 6.6.8) */
+ return 0;
+}
+
+static inline int dccp_feat_is_reserved(const u8 feat)
+{
+ return (feat > DCCPF_DATA_CHECKSUM &&
+ feat < DCCPF_MIN_CCID_SPECIFIC) ||
+ feat == DCCPF_RESERVED;
+}
+
+/* feature negotiation knows only these four option types (RFC 4340, sec. 6) */
+static inline int dccp_feat_is_valid_type(const u8 optnum)
+{
+ return optnum >= DCCPO_CHANGE_L && optnum <= DCCPO_CONFIRM_R;
+
+}
+
+#ifdef CONFIG_IP_DCCP_DEBUG
+extern const char *dccp_feat_typename(const u8 type);
+extern const char *dccp_feat_name(const u8 feat);
+
+static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)
+{
+ dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type),
+ dccp_feat_name(feat), feat, val);
+}
+#else
+#define dccp_feat_debug(type, feat, val)
+#endif /* CONFIG_IP_DCCP_DEBUG */