+ * @extract.from_hdr: Used when 'type = DPKG_EXTRACT_FROM_HDR'
+ * @extract.from_data: Used when 'type = DPKG_EXTRACT_FROM_DATA'
+ * @extract.from_parse: Used when 'type = DPKG_EXTRACT_FROM_PARSE'
+ * @extract.from_hdr.prot: Any of the supported headers
+ * @extract.from_hdr.type: Defines the type of header extraction:
+ * DPKG_FROM_HDR: use size & offset below;
+ * DPKG_FROM_FIELD: use field, size and offset below;
+ * DPKG_FULL_FIELD: use field below
+ * @extract.from_hdr.field: One of the supported fields (NH_FLD_)
+ * @extract.from_hdr.size: Size in bytes
+ * @extract.from_hdr.offset: Byte offset
+ * @extract.from_hdr.hdr_index: Clear for cases not listed below;
+ * Used for protocols that may have more than a single
+ * header, 0 indicates an outer header;
+ * Supported protocols (possible values):
+ * NET_PROT_VLAN (0, HDR_INDEX_LAST);
+ * NET_PROT_MPLS (0, 1, HDR_INDEX_LAST);
+ * NET_PROT_IP(0, HDR_INDEX_LAST);
+ * NET_PROT_IPv4(0, HDR_INDEX_LAST);
+ * NET_PROT_IPv6(0, HDR_INDEX_LAST);
+ * @extract.from_data.size: Size in bytes
+ * @extract.from_data.offset: Byte offset
+ * @extract.from_parse.size: Size in bytes
+ * @extract.from_parse.offset: Byte offset