/* * lib/cache.c Caching Module * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation version 2.1 * of the License. * * Copyright (c) 2003-2006 Thomas Graf */ /** * @ingroup cache_mngt * @defgroup cache Cache * * @code * Cache Management | | Type Specific Cache Operations * * | | +----------------+ +------------+ * | request update | | msg_parser | * | | +----------------+ +------------+ * +- - - - -^- - - - - - - -^- -|- - - - * nl_cache_update: | | | | * 1) --------- co_request_update ------+ | | * | | | * 2) destroy old cache +----------- pp_cb ---------|---+ * | | | * 3) ---------- nl_recvmsgs ----------+ +- cb_valid -+ * +--------------+ | | | | * | nl_cache_add |<-----+ + - - -v- -|- - - - - - - - - - - * +--------------+ | | +-------------+ * | nl_recvmsgs | * | | +-----|-^-----+ * +---v-|---+ * | | | nl_recv | * +---------+ * | | Core Netlink * @endcode * * @{ */ #include #include #include #include #include /** * @name Access Functions * @{ */ /** * Return the number of items in the cache * @arg cache cache handle */ int nl_cache_nitems(struct nl_cache *cache) { return cache->c_nitems; } /** * Return the number of items matching a filter in the cache * @arg cache Cache object. * @arg filter Filter object. */ int nl_cache_nitems_filter(struct nl_cache *cache, struct nl_object *filter) { struct nl_object_ops *ops; struct nl_object *obj; int nitems = 0; if (cache->c_ops == NULL) BUG(); ops = cache->c_ops->co_obj_ops; nl_list_for_each_entry(obj, &cache->c_items, ce_list) { if (filter && !nl_object_match_filter(obj, filter)) continue; nitems++; } return nitems; } /** * Returns \b true if the cache is empty. * @arg cache Cache to check * @return \a true if the cache is empty, otherwise \b false is returned. */ int nl_cache_is_empty(struct nl_cache *cache) { return nl_list_empty(&cache->c_items); } /** * Return the operations set of the cache * @arg cache cache handle */ struct nl_cache_ops *nl_cache_get_ops(struct nl_cache *cache) { return cache->c_ops; } /** * Return the first element in the cache * @arg cache cache handle */ struct nl_object *nl_cache_get_first(struct nl_cache *cache) { if (nl_list_empty(&cache->c_items)) return NULL; return nl_list_entry(cache->c_items.next, struct nl_object, ce_list); } /** * Return the last element in the cache * @arg cache cache handle */ struct nl_object *nl_cache_get_last(struct nl_cache *cache) { if (nl_list_empty(&cache->c_items)) return NULL; return nl_list_entry(cache->c_items.prev, struct nl_object, ce_list); } /** * Return the next element in the cache * @arg obj current object */ struct nl_object *nl_cache_get_next(struct nl_object *obj) { if (nl_list_at_tail(obj, &obj->ce_cache->c_items, ce_list)) return NULL; else return nl_list_entry(obj->ce_list.next, struct nl_object, ce_list); } /** * Return the previous element in the cache * @arg obj current object */ struct nl_object *nl_cache_get_prev(struct nl_object *obj) { if (nl_list_at_head(obj, &obj->ce_cache->c_items, ce_list)) return NULL; else return nl_list_entry(obj->ce_list.prev, struct nl_object, ce_list); } /** @} */ /** * @name Cache Creation/Deletion * @{ */ /** * Allocate an empty cache * @arg ops cache operations to base the cache on * * @return A newly allocated and initialized cache. */ struct nl_cache *nl_cache_alloc(struct nl_cache_ops *ops) { struct nl_cache *cache; cache = calloc(1, sizeof(*cache)); if (!cache) { nl_errno(ENOMEM); return NULL; } nl_init_list_head(&cache->c_items); cache->c_ops = ops; NL_DBG(2, "Allocated cache %p <%s>.\n", cache, nl_cache_name(cache)); return cache; } /** * Allocate an empty cache based on type name * @arg kind Name of cache type * @return A newly allocated and initialized cache. */ struct nl_cache *nl_cache_alloc_name(const char *kind) { struct nl_cache_ops *ops; ops = nl_cache_ops_lookup(kind); if (!ops) { nl_error(ENOENT, "Unable to lookup cache \"%s\"", kind); return NULL; } return nl_cache_alloc(ops); } /** * Allocate a new cache containing a subset of a cache * @arg orig Original cache to be based on * @arg filter Filter defining the subset to be filled into new cache * @return A newly allocated cache or NULL. */ struct nl_cache *nl_cache_subset(struct nl_cache *orig, struct nl_object *filter) { struct nl_cache *cache; struct nl_object_ops *ops; struct nl_object *obj; if (!filter) BUG(); cache = nl_cache_alloc(orig->c_ops); if (!cache) return NULL; ops = orig->c_ops->co_obj_ops; nl_list_for_each_entry(obj, &orig->c_items, ce_list) { if (!nl_object_match_filter(obj, filter)) continue; nl_cache_add(cache, obj); } return cache; } /** * Clear a cache. * @arg cache cache to clear * * Removes all elements of a cache. */ void nl_cache_clear(struct nl_cache *cache) { struct nl_object *obj, *tmp; NL_DBG(1, "Clearing cache %p <%s>...\n", cache, nl_cache_name(cache)); nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) nl_cache_remove(obj); } /** * Free a cache. * @arg cache Cache to free. * * Removes all elements of a cache and frees all memory. * * @note Use this function if you are working with allocated caches. */ void nl_cache_free(struct nl_cache *cache) { nl_cache_clear(cache); NL_DBG(1, "Freeing cache %p <%s>...\n", cache, nl_cache_name(cache)); free(cache); } /** @} */ /** * @name Cache Modifications * @{ */ static int __cache_add(struct nl_cache *cache, struct nl_object *obj) { obj->ce_cache = cache; nl_list_add_tail(&obj->ce_list, &cache->c_items); cache->c_nitems++; NL_DBG(1, "Added %p to cache %p <%s>.\n", obj, cache, nl_cache_name(cache)); return 0; } /** * Add object to a cache. * @arg cache Cache to add object to * @arg obj Object to be added to the cache * * Adds the given object to the specified cache. The object is cloned * if it has been added to another cache already. * * @return 0 or a negative error code. */ int nl_cache_add(struct nl_cache *cache, struct nl_object *obj) { struct nl_object *new; if (cache->c_ops->co_obj_ops != obj->ce_ops) return nl_error(EINVAL, "Object mismatches cache type"); if (!nl_list_empty(&obj->ce_list)) { new = nl_object_clone(obj); if (!new) return nl_errno(ENOMEM); } else { nl_object_get(obj); new = obj; } return __cache_add(cache, new); } /** * Move object from one cache to another * @arg cache Cache to move object to. * @arg obj Object subject to be moved * * Removes the given object from its associated cache if needed * and adds it to the new cache. * * @return 0 on success or a negative error code. */ int nl_cache_move(struct nl_cache *cache, struct nl_object *obj) { if (cache->c_ops->co_obj_ops != obj->ce_ops) return nl_error(EINVAL, "Object mismatches cache type"); NL_DBG(3, "Moving object %p to cache %p\n", obj, cache); /* Acquire reference, if already in a cache this will be * reverted during removal */ nl_object_get(obj); if (!nl_list_empty(&obj->ce_list)) nl_cache_remove(obj); return __cache_add(cache, obj); } /** * Removes an object from a cache. * @arg obj Object to remove from its cache * * Removes the object \c obj from the cache it is assigned to, since * an object can only be assigned to one cache at a time, the cache * must ne be passed along with it. */ void nl_cache_remove(struct nl_object *obj) { struct nl_cache *cache = obj->ce_cache; if (cache == NULL) return; nl_list_del(&obj->ce_list); obj->ce_cache = NULL; nl_object_put(obj); cache->c_nitems--; NL_DBG(1, "Deleted %p from cache %p <%s>.\n", obj, cache, nl_cache_name(cache)); } /** * Search for an object in a cache * @arg cache Cache to search in. * @arg needle Object to look for. * * Iterates over the cache and looks for an object with identical * identifiers as the needle. * * @return Reference to object or NULL if not found. * @note The returned object must be returned via nl_object_put(). */ struct nl_object *nl_cache_search(struct nl_cache *cache, struct nl_object *needle) { struct nl_object *obj; nl_list_for_each_entry(obj, &cache->c_items, ce_list) { if (nl_object_identical(obj, needle)) { nl_object_get(obj); return obj; } } return NULL; } /** @} */ /** * @name Synchronization * @{ */ /** * Request a full dump from the kernel to fill a cache * @arg handle Netlink handle * @arg cache Cache subjected to be filled. * * Send a dumping request to the kernel causing it to dump all objects * related to the specified cache to the netlink socket. * * Use nl_cache_pickup() to read the objects from the socket and fill them * into a cache. */ int nl_cache_request_full_dump(struct nl_handle *handle, struct nl_cache *cache) { NL_DBG(2, "Requesting dump from kernel for cache %p <%s>...\n", cache, nl_cache_name(cache)); if (cache->c_ops->co_request_update == NULL) return nl_error(EOPNOTSUPP, "Operation not supported"); return cache->c_ops->co_request_update(cache, handle); } /** @cond SKIP */ struct update_xdata { struct nl_cache_ops *ops; struct nl_parser_param *params; }; static int update_msg_parser(struct nl_msg *msg, void *arg) { struct update_xdata *x = arg; return nl_cache_parse(x->ops, &msg->nm_src, msg->nm_nlh, x->params); } /** @endcond */ int __cache_pickup(struct nl_handle *handle, struct nl_cache *cache, struct nl_parser_param *param) { int err; struct nl_cb *cb; struct update_xdata x = { .ops = cache->c_ops, .params = param, }; NL_DBG(1, "Picking up answer for cache %p <%s>...\n", cache, nl_cache_name(cache)); cb = nl_cb_clone(handle->h_cb); if (cb == NULL) return nl_get_errno(); nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x); err = nl_recvmsgs(handle, cb); if (err < 0) NL_DBG(2, "While picking up for %p <%s>, recvmsgs() returned " \ "%d: %s", cache, nl_cache_name(cache), err, nl_geterror()); nl_cb_put(cb); return err; } static int pickup_cb(struct nl_object *c, struct nl_parser_param *p) { return nl_cache_add((struct nl_cache *) p->pp_arg, c); } /** * Pickup a netlink dump response and put it into a cache. * @arg handle Netlink handle. * @arg cache Cache to put items into. * * Waits for netlink messages to arrive, parses them and puts them into * the specified cache. * * @return 0 on success or a negative error code. */ int nl_cache_pickup(struct nl_handle *handle, struct nl_cache *cache) { struct nl_parser_param p = { .pp_cb = pickup_cb, .pp_arg = cache, }; return __cache_pickup(handle, cache, &p); } static int cache_include(struct nl_cache *cache, struct nl_object *obj, struct nl_msgtype *type, change_func_t cb) { struct nl_object *old; switch (type->mt_act) { case NL_ACT_NEW: case NL_ACT_DEL: old = nl_cache_search(cache, obj); if (old) { nl_cache_remove(old); if (type->mt_act == NL_ACT_DEL) { if (cb) cb(cache, old, NL_ACT_DEL); nl_object_put(old); } } if (type->mt_act == NL_ACT_NEW) { nl_cache_move(cache, obj); if (old == NULL && cb) cb(cache, obj, NL_ACT_NEW); else if (old) { if (nl_object_diff(old, obj) && cb) cb(cache, obj, NL_ACT_CHANGE); nl_object_put(old); } } break; default: NL_DBG(2, "Unknown action associated to object %p\n", obj); return 0; } return 0; } int nl_cache_include(struct nl_cache *cache, struct nl_object *obj, change_func_t change_cb) { struct nl_cache_ops *ops = cache->c_ops; int i; if (ops->co_obj_ops != obj->ce_ops) return nl_error(EINVAL, "Object mismatches cache type"); for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) if (ops->co_msgtypes[i].mt_id == obj->ce_msgtype) return cache_include(cache, obj, &ops->co_msgtypes[i], change_cb); return nl_errno(EINVAL); } static int resync_cb(struct nl_object *c, struct nl_parser_param *p) { struct nl_cache_assoc *ca = p->pp_arg; return nl_cache_include(ca->ca_cache, c, ca->ca_change); } int nl_cache_resync(struct nl_handle *handle, struct nl_cache *cache, change_func_t change_cb) { struct nl_object *obj, *next; struct nl_cache_assoc ca = { .ca_cache = cache, .ca_change = change_cb, }; struct nl_parser_param p = { .pp_cb = resync_cb, .pp_arg = &ca, }; int err; NL_DBG(1, "Resyncing cache %p <%s>...\n", cache, nl_cache_name(cache)); /* Mark all objects so we can see if some of them are obsolete */ nl_cache_mark_all(cache); err = nl_cache_request_full_dump(handle, cache); if (err < 0) goto errout; err = __cache_pickup(handle, cache, &p); if (err < 0) goto errout; nl_list_for_each_entry_safe(obj, next, &cache->c_items, ce_list) if (nl_object_is_marked(obj)) nl_cache_remove(obj); NL_DBG(1, "Finished resyncing %p <%s>\n", cache, nl_cache_name(cache)); err = 0; errout: return err; } /** @} */ /** * @name Parsing * @{ */ /** @cond SKIP */ int nl_cache_parse(struct nl_cache_ops *ops, struct sockaddr_nl *who, struct nlmsghdr *nlh, struct nl_parser_param *params) { int i, err; if (!nlmsg_valid_hdr(nlh, ops->co_hdrsize)) { err = nl_error(EINVAL, "netlink message too short to be " "of kind %s", ops->co_name); goto errout; } for (i = 0; ops->co_msgtypes[i].mt_id >= 0; i++) { if (ops->co_msgtypes[i].mt_id == nlh->nlmsg_type) { err = ops->co_msg_parser(ops, who, nlh, params); if (err != -ENOENT) goto errout; } } err = nl_error(EINVAL, "Unsupported netlink message type %d", nlh->nlmsg_type); errout: return err; } /** @endcond */ /** * Parse a netlink message and add it to the cache. * @arg cache cache to add element to * @arg msg netlink message * * Parses a netlink message by calling the cache specific message parser * and adds the new element to the cache. * * @return 0 or a negative error code. */ int nl_cache_parse_and_add(struct nl_cache *cache, struct nl_msg *msg) { struct nl_parser_param p = { .pp_cb = pickup_cb, .pp_arg = cache, }; return nl_cache_parse(cache->c_ops, NULL, nlmsg_hdr(msg), &p); } /** * (Re)fill a cache with the contents in the kernel. * @arg handle netlink handle * @arg cache cache to update * * Clears the specified cache and fills it with the current state in * the kernel. * * @return 0 or a negative error code. */ int nl_cache_refill(struct nl_handle *handle, struct nl_cache *cache) { int err; err = nl_cache_request_full_dump(handle, cache); if (err < 0) return err; NL_DBG(2, "Upading cache %p <%s>, request sent, waiting for dump...\n", cache, nl_cache_name(cache)); nl_cache_clear(cache); return nl_cache_pickup(handle, cache); } /** @} */ /** * @name Utillities * @{ */ /** * Mark all objects in a cache * @arg cache Cache to mark all objects in */ void nl_cache_mark_all(struct nl_cache *cache) { struct nl_object *obj; NL_DBG(2, "Marking all objects in cache %p <%s>...\n", cache, nl_cache_name(cache)); nl_list_for_each_entry(obj, &cache->c_items, ce_list) nl_object_mark(obj); } /** @} */ /** * @name Dumping * @{ */ /** * Dump all elements of a cache. * @arg cache cache to dump * @arg params dumping parameters * * Dumps all elements of the \a cache to the file descriptor \a fd. */ void nl_cache_dump(struct nl_cache *cache, struct nl_dump_params *params) { nl_cache_dump_filter(cache, params, NULL); } /** * Dump all elements of a cache (filtered). * @arg cache cache to dump * @arg params dumping parameters (optional) * @arg filter filter object * * Dumps all elements of the \a cache to the file descriptor \a fd * given they match the given filter \a filter. */ void nl_cache_dump_filter(struct nl_cache *cache, struct nl_dump_params *params, struct nl_object *filter) { int type = params ? params->dp_type : NL_DUMP_FULL; struct nl_object_ops *ops; struct nl_object *obj; NL_DBG(2, "Dumping cache %p <%s> filter %p\n", cache, nl_cache_name(cache), filter); if (type > NL_DUMP_MAX || type < 0) BUG(); if (cache->c_ops == NULL) BUG(); ops = cache->c_ops->co_obj_ops; if (!ops->oo_dump[type]) return; nl_list_for_each_entry(obj, &cache->c_items, ce_list) { if (filter && !nl_object_match_filter(obj, filter)) continue; NL_DBG(4, "Dumping object %p...\n", obj); dump_from_ops(obj, params); } } /** @} */ /** * @name Iterators * @{ */ /** * Call a callback on each element of the cache. * @arg cache cache to iterate on * @arg cb callback function * @arg arg argument passed to callback function * * Calls a callback function \a cb on each element of the \a cache. * The argument \a arg is passed on the callback function. */ void nl_cache_foreach(struct nl_cache *cache, void (*cb)(struct nl_object *, void *), void *arg) { nl_cache_foreach_filter(cache, NULL, cb, arg); } /** * Call a callback on each element of the cache (filtered). * @arg cache cache to iterate on * @arg filter filter object * @arg cb callback function * @arg arg argument passed to callback function * * Calls a callback function \a cb on each element of the \a cache * that matches the \a filter. The argument \a arg is passed on * to the callback function. */ void nl_cache_foreach_filter(struct nl_cache *cache, struct nl_object *filter, void (*cb)(struct nl_object *, void *), void *arg) { struct nl_object *obj, *tmp; struct nl_object_ops *ops; if (cache->c_ops == NULL) BUG(); ops = cache->c_ops->co_obj_ops; nl_list_for_each_entry_safe(obj, tmp, &cache->c_items, ce_list) { if (filter && !nl_object_match_filter(obj, filter)) continue; cb(obj, arg); } } /** @} */ /** @} */