From 3c6269b8fec71fa22d5b087cae0e9ef86ff2b351 Mon Sep 17 00:00:00 2001 From: Martin Mares Date: Fri, 2 Jun 2000 13:42:36 +0000 Subject: Added documentation on protocols. Protocol hooks deserve an extra chapter (to come soon). --- nest/proto.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) (limited to 'nest/proto.c') diff --git a/nest/proto.c b/nest/proto.c index 5ec793e..8275638 100644 --- a/nest/proto.c +++ b/nest/proto.c @@ -85,6 +85,20 @@ proto_relink(struct proto *p) proto_enqueue(l, p); } +/** + * proto_new - create a new protocol instance + * @c: protocol configuration + * @size: size of protocol data structure (each protocol instance is represented by + * a structure starting with generic part [struct &proto] and continued + * with data specific to the protocol) + * + * When a new configuration has been read in, the core code starts + * initializing all the protocol instandces configured by calling their + * init() hooks with the corresponding instance configuration. The initialization + * code of the protocol is expected to create a new instance according to the + * configuration by calling this function and then modifying the default settings + * to values wanted by the protocol. + */ void * proto_new(struct proto_config *c, unsigned size) { @@ -116,6 +130,20 @@ proto_init_instance(struct proto *p) rt_lock_table(p->table); } +/** + * proto_add_announce_hook - connect protocol to a routing table + * @p: protocol instance + * @t: routing table to connect to + * + * This function creates a connection between the protocol instance @p + * and the routing table @t, making the protocol hear all changes in + * the table. + * + * Unless you want to listen to multiple routing tables (as the Pipe + * protocol does), you needn't to worry about this function since the + * connection to the protocol's primary routing table is initialized + * automatically by the core code. + */ struct announce_hook * proto_add_announce_hook(struct proto *p, struct rtable *t) { @@ -144,6 +172,19 @@ proto_flush_hooks(struct proto *p) p->ahooks = NULL; } +/** + * proto_config_new - create a new protocol configuration + * @pr: protocol the configuration will belong to + * @size: size of the structure including generic data + * + * Whenever the configuration file says that a new instance + * of a routing protocol should be created, the parser calls + * proto_config_new() to create a configuration entry for this + * instance (a structure staring with the &proto_config header + * containing all the generic items followed by protocol-specific + * ones). Also, the configuration entry gets added to the list + * of protocol instances kept in the configuration. + */ void * proto_config_new(struct protocol *pr, unsigned size) { @@ -159,6 +200,14 @@ proto_config_new(struct protocol *pr, unsigned size) return c; } +/** + * protos_preconfig - pre-configuration processing + * @c: new configuration + * + * This function calls the preconfig() hooks of all routing + * protocols available to prepare them for reading of the new + * configuration. + */ void protos_preconfig(struct config *c) { @@ -176,6 +225,13 @@ protos_preconfig(struct config *c) DBG("\n"); } +/** + * protos_postconfig - post-configuration processing + * @c: new configuration + * + * This function calls the postconfig() hooks of all protocol + * instances specified in configuration @c. + */ void protos_postconfig(struct config *c) { @@ -207,6 +263,31 @@ proto_init(struct proto_config *c) return q; } +/** + * protos_commit - commit new protocol configuration + * @new: new configuration + * @old: old configuration or %NULL if it's boot time config + * @force_reconfig: force restart of all protocols (used for example + * when the router ID changes) + * + * Scan differences between @old and @new configuration and adjust all + * protocol instances to conform to the new configuration. + * + * When a protocol exists in the new configuration, but it doesn't in the + * original one, it's immediately started. When a collision with the other + * running protocol would arise, the new protocol will be temporarily stopped + * by the locking mechanism. + * + * When a protocol exists in the old configuration, but it doesn't in the + * new one, it's shut down and deleted after the shutdown completes. + * + * When a protocol exists in both configurations, the core decides whether + * it's possible to reconfigure it dynamically (it checks all the core properties + * of the protocol and if they match, it asks the reconfigure() hook of the + * protocol to see if the protocol is able to switch to the new configuration). + * If it isn't possible, the protocol is shut down and a new instance is started + * with the new configuration after the shutdown is completed. + */ void protos_commit(struct config *new, struct config *old, int force_reconfig) { @@ -332,6 +413,15 @@ proto_rethink_goal(struct proto *p) } } +/** + * protos_dump_all - dump status of all protocols + * + * This function dumps status of all existing protocol instances to the + * debug output. It involves printing of general status information + * such as protocol states, its position on the protocol lists + * and also calling of a dump() hook of the protocol to print + * the internals. + */ void protos_dump_all(void) { @@ -360,6 +450,14 @@ protos_dump_all(void) debug(" flushing %s\n", p->name); } +/** + * proto_build - make a single protocol available + * @p: the protocol + * + * After the platform specific initialization code uses protos_build() + * to add all the standard protocols, it should call proto_build() for + * all platform specific protocols to infrom the core that they exist. + */ void proto_build(struct protocol *p) { @@ -371,6 +469,15 @@ proto_build(struct protocol *p) } } +/** + * protos_build - build a protocol list + * + * This function is called during BIRD startup to insert + * all standard protocols to the global protocol list. Insertion + * of platform specific protocols (such as the kernel syncer) + * is in the domain of competence of the platform dependent + * startup code. + */ void protos_build(void) { @@ -441,6 +548,18 @@ proto_feed(void *P) proto_feed_more(P); } +/** + * proto_notify_state - notify core about protocol state change + * @p: protocol the state of which has changed + * @ps: the new status + * + * Whenever a state of a protocol changes due to some event internal + * to the protocol (i.e., not inside a start() or shutdown() hook), + * it should immediately notify the core about the change by calling + * proto_notify_state() which will write the new state to the &proto + * structure and take all the actions necessary to adapt to the new + * state. + */ void proto_notify_state(struct proto *p, unsigned ps) { -- cgit v1.2.3