Documented protocol hooks.

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+/*
+ *	BIRD -- Documentation for Protocol Hooks (dummy source file)
+ *
+ *	(c) 2000 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+/**
+ * DOC: Protocol hooks
+ *
+ * Each protocol provides a rich set of hook functions referred to by pointers
+ * in either the &proto or &protocol structure. They are called by the core whenever
+ * it wants the protocol to perform some action or to notify the protocol about
+ * any change of its environment. All of the hooks can be set to %NULL which means
+ * to ignore the change or to take a default action.
+ */
+
+/**
+ * preconfig - protocol preconfiguration
+ * @p: a routing protocol
+ * @c: new configuration
+ *
+ * The preconfig() hook is called before parsing of a new configuration.
+ */
+void preconfig(struct protocol *p, struct config *c)
+{ DUMMY; }
+
+/**
+ * postconfig - instance post-configuration
+ * @c: instance configuration
+ *
+ * The postconfig() hook is called for each configured instance after
+ * parsing of the new configuration is finished.
+ */
+void postconfig(struct proto_config *c)
+{ DUMMY; }
+
+/**
+ * init - initialize an instance
+ * @c: instance configuration
+ *
+ * The init() hook is called by the core to create a protocol instance
+ * according to supplied protocol configuration.
+ *
+ * Result: a pointer to the instance created
+ */
+struct proto *init(struct proto_config *c)
+{ DUMMY; }
+
+/**
+ * reconfigure - request instance reconfiguration
+ * @p: an instance
+ * @c: new configuration
+ *
+ * The core calls the reconfigure() hook whenever it wants to ask the
+ * protocol for switching to a new configuration. If the reconfiguration
+ * is possible, the hook returns 1. Otherwise, it returns 0 and the core
+ * will shut down the instance and start a new one with the new configuration.
+ *
+ * After the protocol confirms reconfiguration, it must no longer keep any
+ * references to the old configuration since the memory it's stored in can
+ * be re-used at any time.
+ */
+int reconfigure(struct proto *p, struct proto_config *c)
+{ DUMMY; }
+
+/**
+ * dump - dump protocol state
+ * @p: an instance
+ *
+ * This hook dumps the complete state of the instance to the
+ * debug output.
+ */
+void dump(struct proto *p)
+{ DUMMY; }
+
+/**
+ * dump_attrs - dump protocol-dependent attributes
+ * @e: a route entry
+ *
+ * This hook dumps all attributes in the &rte which belong to this
+ * protocol to the debug output.
+ */
+void dump_attrs(rte *e)
+{ DUMMY; }
+
+/**
+ * start - request instance startup
+ * @p: protocol instance
+ *
+ * The start() hook is called by the core when it wishes to start
+ * the instance.
+ *
+ * Result: new protocol state
+ */
+int start(struct proto *p)
+{ DUMMY; }
+
+/**
+ * shutdown - request instance shutdown
+ * @p: protocol instance
+ *
+ * The stop() hook is called by the core when it wishes to shut
+ * the instance down for some reason.
+ *
+ * Returns: new protocol state
+ */
+int shutdown(struct proto *p)
+{ DUMMY; }
+
+/**
+ * get_status - get instance status
+ * @p: protocol instance
+ * @buf: buffer to be filled with the status string
+ *
+ * This hook is called by the core if it wishes to obtain an brief one-line user friendly
+ * representation of the status of the instance to be printed by the <cf/show protocols/
+ * command.
+ */
+void get_status(struct proto *p, byte *buf)
+{ DUMMY; }
+
+/**
+ * get_route_info - get route information
+ * @e: a route entry
+ * @buf: buffer to be filled with the resulting string
+ * @attrs: extended attributes of the route
+ *
+ * This hook is called to fill the buffer @buf with a brief user friendly
+ * representation of metrics of a route belonging to this protocol.
+ */
+void get_route_info(rte *e, byte *buf, ea_list *attrs)
+{ DUMMY; }
+
+/**
+ * get_attr - get attribute information
+ * @a: an extended attribute
+ * @buf: buffer to be filled with attribute information
+ *
+ * The get_attr() hook is called by the core to obtain a user friendly
+ * representation of an extended route attribute. It can either leave
+ * the whole conversion to the core (by returning %GA_UNKNOWN), fill
+ * in only attribute name (and let the core format the attribute value
+ * automatically according to the type field; by returning %GA_NAME)
+ * or doing the whole conversion (used in case the value requires extra
+ * care; return %GA_FULL).
+ */
+int get_attr(eattr *a, byte *buf)
+{ DUMMY; }
+
+/**
+ * if_notify - notify instance about interface changes
+ * @p: protocol instance
+ * @flags: interface change flags
+ * @i: the interface in question
+ *
+ * This hook is called whenever any network interface changes its status.
+ * The change is described by a combination of status bits (%IF_CHANGE_xxx)
+ * in the @flags parameter.
+ */
+void if_notify(struct proto *p, unsigned flags, struct iface *i)
+{ DUMMY; }
+
+/**
+ * ifa_notify - notify instance about interface address changes
+ * @p: protocol instance
+ * @flags: address change flags
+ * @a: the interface address
+ *
+ * This hook is called to notify the protocol instance about an interface
+ * acquiring or losing one of its addresses. The change is described by
+ * a combination of status bits (%IF_CHANGE_xxx) in the @flags parameter.
+ */
+void ifa_notify(struct proto *p, unsigned flags, struct ifa *a)
+{ DUMMY; }
+
+/**
+ * rt_notify - notify instance about routing table change
+ * @p: protocol instance
+ * @net: a network entry
+ * @new: new optimal route for the network
+ * @old: old optimal route for the network
+ * @attrs: extended attributes associated with the @new entry
+ *
+ * The rt_notify() hook is called to inform the protocol instance about
+ * changes in the routing table it's connected to, that is a route @old
+ * belonging to network @net being replaced by a new route @new with
+ * extended attributes @attrs. Either @new or @old or both can be %NULL
+ * if the corresponding route doesn't exist.
+ */
+void rt_notify(struct proto *p, net *net, rte *new, rte *old, ea_list *attrs)
+{ DUMMY; }
+
+/**
+ * neigh_notify - notify instance about neighbor status change
+ * @neigh: a neighbor cache entry
+ *
+ * The neigh_notify() hook is called by the neighbor cache whenever
+ * a neighbor changes its state, that is it gets disconnected or a
+ * sticky neighbor gets connected.
+ */
+void neigh_notify(neighbor *neigh)
+{ DUMMY; }
+
+/**
+ * make_tmp_attrs - convert embedded attributes to temporary ones
+ * @e: route entry
+ * @pool: linear pool to allocate attribute memory in
+ *
+ * This hook is called by the routing table functions if they need
+ * to convert the protocol attributes embedded directly in the &rte
+ * to temporary extended attributes in order to distribute them
+ * to other protocols or to filters. make_tmp_attrs() creates
+ * an &ea_list in the linpool @pool, fills it with values of the
+ * temporary attributes and returns a pointer to it.
+ */
+ea_list *make_tmp_attrs(rte *e, struct linpool *pool)
+{ DUMMY; }
+
+/**
+ * store_tmp_attrs - convert temporary attributes to embedded ones
+ * @e: route entry
+ * @attrs: temporary attributes to be converted
+ *
+ * This hook is an exact opposite of make_tmp_attrs() -- it takes
+ * a list of extended attributes and converts them to attributes
+ * embedded in the &rte corresponding to this protocol.
+ *
+ * You must be prepared for any of the attributes being missing
+ * from the list and use default values instead.
+ */
+void store_tmp_attrs(rte *e, ea_list *attrs)
+{ DUMMY; }
+
+/**
+ * import_control - pre-filtering decisions on route import
+ * @p: protocol instance the route is going to be imported to
+ * @e: the route in question
+ * @attrs: extended attributes of the route
+ * @pool: linear pool for allocation of all temporary data
+ *
+ * The import_control() hook is called as the first step of a exporting
+ * a route from a routing table to the protocol instance. It can modify
+ * route attributes and force acceptance or rejection of the route regardless
+ * of user-specified filters. See rte_announce() for a complete description
+ * of the route distribution process.
+ *
+ * The standard use of this hook is to reject routes having originated
+ * from the same instance and to set default values of the protocol's metrics.
+ *
+ * Result: -1 if the route has to be accepted, 1 if rejected and 0 if it
+ * should be passed to the filters.
+ */
+int import_control(struct proto *p, rte **e, ea_list **attrs, struct linpool *pool)
+{ DUMMY; }
+
+/**
+ * rte_better - compare metrics of two routes
+ * @new: the new route
+ * @old: the original route
+ *
+ * This hook gets called when the routing table contains two routes
+ * for the same network which have originated from different instances
+ * of a single protocol and it wants to select which one is preferred
+ * over the other one. Protocols usually decide according to route metrics.
+ *
+ * Result: 1 if @new is better (more preferred) than @old, 0 otherwise.
+ */
+int rte_better(rte *new, rte *old)
+{ DUMMY; }
+
+/**
+ * rte_same - compare two routes
+ * @e1: route
+ * @e2: route
+ *
+ * The rte_same() hook tests whether the routes @e1 and @e2 belonging
+ * to the same protocol instance have identical contents. Contents of
+ * &rta, all the extended attributes and &rte preference are checked
+ * by the core code, no need to take care of them here.
+ *
+ * Result: 1 if @e1 is identical to @e2, 0 otherwise.
+ */
+int rte_same(rte *e1, rte *e2)
+{ DUMMY; }
+
+/**
+ * rte_insert - notify instance about route insertion
+ * @n: network
+ * @e: route
+ *
+ * This hook is called whenever a &rte belonging to the instance
+ * is accepted for insertion to a routing table.
+ *
+ * Please avoid using this function in new protocols.
+ */
+void rte_insert(net *n, rte *e)
+{ DUMMY; }
+
+/**
+ * rte_remove - notify instance about route removal
+ * @n: network
+ * @e: route
+ *
+ * This hook is called whenever a &rte belonging to the instance
+ * is removed from a routing table.
+ *
+ * Please avoid using this function in new protocols.
+ */
+void rte_remove(net *n, rte *e)
+{ DUMMY; }