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/* $Id: oc_membership.h,v 1.10 2005/06/12 07:34:42 alan Exp $ */ #ifndef OCF_OC_MEMBERSHIP_H # define OCF_OC_MEMBERSHIP_H /* * <ocf/oc_membership.h> - membership APIs (version 0.1) * * The structures and functions in this header file work closely with * the oc_event.h event infrastructure. All (edata, esize) parameters * to functions in this header file refer to membership event bodies. * It is expected that all such are received by this mechanism. * * * There are a few things in this header file which don't really belong here * but are needed and they aren't in any other header file. * * These are: * definition of oc_node_id_t * oc_cluster_handle_t * * Maybe we ought to put common types into an <ocf/oc_types.h> * * The oc_cmp_node_id() and oc_localnodeid() functions also belong in * some more global header file. * * oc_member_eventttype_t and * oc_member_uniqueid_t are membership-unique * and don't belong in a set of ocf-common header files (IMHO) * * Copyright (C) 2002 Alan Robertson <alanr@unix.sh> * * This copyright will be assigned to the Free Standards Group * in the future. * * This library is free software; you can redistribute it and/or * modify it under the terms of version 2.1 of the GNU Lesser General Public * License as published by the Free Software Foundation. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <stddef.h> #include <ocf/oc_event.h> #include <clplumbing/cl_uuid.h> /* * This enumeration is used both to indicated the type of an event * received, and to request the types of events one wants delivered. * (see oc_member_request_events() and oc_member_etype() for more * details on how this is used). */ enum oc_member_eventtype_e { OC_NOT_MEMBERSHIP, /* Not a (valid) membership event */ OC_FULL_MEMBERSHIP, /* full membership update */ OC_INCR_MEMBERSHIP /* incremental membership update */ }; typedef enum oc_member_eventtype_e oc_member_eventtype_t; /* controversial? */ typedef void * oc_cluster_handle_t; typedef cl_uuid_t oc_node_id_t; typedef struct oc_member_uniqueid_s oc_member_uniqueid_t; /* * A few words about the oc_node_id_t: * * An oc_node_id_t is assigned to a node no later than when it first * joins a cluster, and it will not change while that node is active * in some partition in the cluster. It is normally expected to * be assigned to a node, and not changed afterwards except by * adminstrative intervention. * * The mechanism for assigning oc_node_id_t's to nodes is outside the * scope of this specification. The only basic operation which * can be performed on these objects is comparison. * * See oc_cmp_node_id() for comparisons between them. */ /* * oc_member_uniqueid_t * The values of these fields are guaranteed to be the same across * all nodes within a given partition, and guaranteed to be different * between all active partitions in the cluster. * * In other words, if you exchange current oc_member_uniqueid_t objects * with another cluster node, you can tell with certainty, whether or not * you and the other node are currently members of the same partition. * * The m_instance field is guaranteed to be unique to a particular * membership instance while that node is active in the cluster. * If a node is shut down and restarts, then the m_instance might * repeat a value it had in the past. * * See oc_cmp_uniqueid() for comparing them. * * The meaning of the uniqueid field is not defined by this specification. * It may be the node_id of a node in the cluster or it may be a unique * checksum or it may be some other value. All that is specified is that * it and the m_instance are unique when taken as a whole. */ typedef unsigned char oc_mbr_uniqueid[16]; struct oc_member_uniqueid_s { unsigned m_instance; oc_mbr_uniqueid uniqueid; }; #ifdef __cplusplus extern "C" { #endif /* * Returns 0 for equal node_ids, * negative for node id l less than node id r * positive for node id l greater than node id r * * No meaning may be ascribed to the fact that a particular * node id is greater or less than some other node id. * The comparison operator is provided primarily for * equality comparisons, and secondarily for use in * sorting them into a canonical order. */ int oc_cmp_node_id(const oc_node_id_t* l, const oc_node_id_t* r); /* Return our local node id */ int oc_localnodeid(oc_node_id_t* us, oc_cluster_handle_t handle); /* * On failure these functions return -1: * The following errno values are defined: * EINVAL invalid handle argument * EL2HLT cluster software not currently running */ /* What kind of event did we get? */ /* (see oc_member_request_events() for more details) */ oc_member_eventtype_t oc_member_etype(const void* edata, size_t esize); /* * oc_member_uniqueid() returns the unique identifier associated * with this membership event. See the description in the typedef * for more details. */ int oc_member_uniqueid(const void* edata, size_t esize, oc_member_uniqueid_t* u); /* * Failure of these functions return -1. * The following errno values are defined: * EL2HLT cluster software not currently running * EINVAL edata does not refer to a membership event */ /* How many nodes of each category do we have? */ int oc_member_n_nodesjoined(const void* edata, size_t esize); int oc_member_n_nodesgone(void* edata, size_t esize); int oc_member_n_nodesconst(void* edata, size_t esize); /* * Failure of these functions return -1. * The following errno values are defined: * EL2HLT cluster software not currently running * EINVAL edata does not refer to a membership event * ENOSYS edata refers to an OC_INCR_MEMBERSHIP update, and * oc_member_n_nodesconst() was called. */ /* What nodes of each category do we have? */ oc_node_id_t* oc_member_nodesjoined(const void* edata, size_t esize); oc_node_id_t* oc_member_nodesgone(void* edata, size_t esize); oc_node_id_t* oc_member_nodesconst(void* edata, size_t esize); /* * Failure of these functions return NULL. * The following errno values are defined: * EL2HLT cluster software not currently running * EINVAL edata does not refer to a membership event * ENOSYS edata refers to an OC_INCR_MEMBERSHIP update, and * oc_member_nodesconst() was called. */ /* * * OC_NO_MEMBERSHIP * No membership events will be delivered. This is the default on opening * a membership event connection. * * OC_FULL_MEMBERSHIP * Deliver all membership information including information on * members that didn't change. In this mode, the oc_member_nodesconst() * call is supported. * * OC_INCR_MEMBERSHIP * Deliver only changed membership events. In this mode, calls to * oc_member_nodesconst(), et al. are not supported. * * Setting OC_FULL_MEMBERSHIP or OC_INCR_MEMBERSHIP will result in the * delivery of a single OC_FULL_MEMBERSHIP event soon after making * this call. Subsequent events will be delivered as received in the * requested style (incremental or full). Because events may already * be pending when this operation is issued, no guarantee can be made * regarding when this triggered event will be delivered. * */ int oc_member_request_events(oc_member_eventtype_t etype, oc_ev_t token); /* * On failure this function returns -1: * The following errno values are defined: * EINVAL invalid etype or handle argument * EL2HLT cluster software not currently running * EBADF invalid oc_ev_t token parameter */ /* * if l.m_instance < r.m_instance then return -1 * if r.m_instance > r.m_instance then return 1 * if l.m_instance == r.m_instance and l.uniqueid == r.uniqueid * then return 0 * otherwise return 2 */ int oc_cmp_uniqueid(const oc_member_uniqueid_t l, const oc_member_uniqueid_t r); #ifdef __cplusplus } #endif #endif