+/* Subfields. */
+void mf_write_subfield(const struct mf_subfield *, const union mf_subvalue *,
+ struct cls_rule *);
+void mf_set_subfield(const struct mf_subfield *, uint64_t value,
+ struct cls_rule *);
+void mf_set_subfield_value(const struct mf_subfield *, uint64_t value,
+ struct flow *);
+
+void mf_read_subfield(const struct mf_subfield *, const struct flow *,
+ union mf_subvalue *);
+uint64_t mf_get_subfield(const struct mf_subfield *, const struct flow *);
+
+
+void mf_format_subfield(const struct mf_subfield *, struct ds *);
+char *mf_parse_subfield__(struct mf_subfield *sf, const char **s);
+const char *mf_parse_subfield(struct mf_subfield *, const char *);
+
+enum ofperr mf_check_src(const struct mf_subfield *, const struct flow *);
+enum ofperr mf_check_dst(const struct mf_subfield *, const struct flow *);
+