From 716ca530e1c4515d8683c9d5be3d56b301758b66 Mon Sep 17 00:00:00 2001 From: James <> Date: Wed, 4 Nov 2015 11:49:21 +0000 Subject: trunk-47381 --- package/libs/libnl-tiny/src/cache.c | 376 ++++++++++++++++++++++++++++++++++++ 1 file changed, 376 insertions(+) create mode 100644 package/libs/libnl-tiny/src/cache.c (limited to 'package/libs/libnl-tiny/src/cache.c') diff --git a/package/libs/libnl-tiny/src/cache.c b/package/libs/libnl-tiny/src/cache.c new file mode 100644 index 0000000..56a1280 --- /dev/null +++ b/package/libs/libnl-tiny/src/cache.c @@ -0,0 +1,376 @@ +/* + * 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) 2003-2008 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 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) + 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; +} + +int nl_cache_alloc_and_fill(struct nl_cache_ops *ops, struct nl_sock *sock, + struct nl_cache **result) +{ + struct nl_cache *cache; + int err; + + if (!(cache = nl_cache_alloc(ops))) + return -NLE_NOMEM; + + if (sock && (err = nl_cache_refill(sock, cache)) < 0) { + nl_cache_free(cache); + return err; + } + + *result = cache; + return 0; +} + +/** + * 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) +{ + if (!cache) + return; + + 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 -NLE_OBJ_MISMATCH; + + if (!nl_list_empty(&obj->ce_list)) { + new = nl_object_clone(obj); + if (!new) + return -NLE_NOMEM; + } else { + nl_object_get(obj); + new = obj; + } + + return __cache_add(cache, new); +} + +/** + * 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)); +} + +/** @} */ + +/** + * @name Synchronization + * @{ + */ + +/** + * Request a full dump from the kernel to fill a cache + * @arg sk Netlink socket. + * @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_sock *sk, 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 -NLE_OPNOTSUPP; + + return cache->c_ops->co_request_update(cache, sk); +} + +/** @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_sock *sk, 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(sk->s_cb); + if (cb == NULL) + return -NLE_NOMEM; + + nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, update_msg_parser, &x); + + err = nl_recvmsgs(sk, 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(err)); + + 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 sk Netlink socket. + * @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_sock *sk, struct nl_cache *cache) +{ + struct nl_parser_param p = { + .pp_cb = pickup_cb, + .pp_arg = cache, + }; + + return __cache_pickup(sk, cache, &p); +} + + +/** @} */ + +/** + * @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)) + return -NLE_MSG_TOOSHORT; + + 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 != -NLE_OPNOTSUPP) + goto errout; + } + } + + + err = -NLE_MSGTYPE_NOSUPPORT; +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 sk Netlink socket. + * @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_sock *sk, struct nl_cache *cache) +{ + int err; + + err = nl_cache_request_full_dump(sk, 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(sk, cache); +} + +/** @} */ -- cgit v1.2.3