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committed 41c6d650f65static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = {/* * net/sched/em_meta.c Metadata ematch * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: Thomas Graf <tgraf@suug.ch> * * ========================================================================== * * The metadata ematch compares two meta objects where each object * represents either a meta value stored in the kernel or a static * value provided by userspace. The objects are not provided by * userspace itself but rather a definition providing the information * to build them. Every object is of a certain type which must be * equal to the object it is being compared to. * * The definition of a objects conists of the type (meta type), a * identifier (meta id) and additional type specific information. * The meta id is either TCF_META_TYPE_VALUE for values provided by * userspace or a index to the meta operations table consisting of * function pointers to type specific meta data collectors returning * the value of the requested meta value. * * lvalue rvalue * +-----------+ +-----------+ * | type: INT | | type: INT | * def | id: DEV | | id: VALUE | * | data: | | data: 3 | * +-----------+ +-----------+ * | | * ---> meta_ops[INT][DEV](...) | * | | * ----------- | * V V * +-----------+ +-----------+ * | type: INT | | type: INT | * obj | id: DEV | | id: VALUE | * | data: 2 |<--data got filled out | data: 3 | * +-----------+ +-----------+ * | | * --------------> 2 equals 3 <-------------- * * This is a simplified schema, the complexity varies depending * on the meta type. Obviously, the length of the data must also * be provided for non-numeric types. * * Additionally, type dependent modifiers such as shift operators * or mask may be applied to extend the functionaliy. As of now, * the variable length type supports shifting the byte string to * the right, eating up any number of octets and thus supporting * wildcard interface name comparisons such as "ppp%" matching * ppp0..9. * * NOTE: Certain meta values depend on other subsystems and are * only available if that subsystem is enabled in the kernel. */​