/*
* lib/cache_mngr.c Cache Manager
*
* 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) 2003-2012 Thomas Graf <tgraf@suug.ch>
*/
/**
* @ingroup cache_mngt
* @defgroup cache_mngr Manager
* @brief Manager keeping caches up to date automatically.
*
* The cache manager keeps caches up to date automatically by listening to
* netlink notifications and integrating the received information into the
* existing cache.
*
* @note This functionality is still considered experimental.
*
* Related sections in the development guide:
* - @core_doc{_cache_manager,Cache Manager}
*
* @{
*
* Header
* ------
* ~~~~{.c}
* #include <netlink/cache.h>
* ~~~~
*/
#include <netlink-private/netlink.h>
#include <netlink/netlink.h>
#include <netlink/cache.h>
#include <netlink/utils.h>
/** @cond SKIP */
#define NASSOC_INIT 16
#define NASSOC_EXPAND 8
/** @endcond */
static int include_cb(struct nl_object *obj, struct nl_parser_param *p)
{
struct nl_cache_assoc *ca = p->pp_arg;
struct nl_cache_ops *ops = ca->ca_cache->c_ops;
NL_DBG(2, "Including object %p into cache %p\n", obj, ca->ca_cache);
#ifdef NL_DEBUG
if (nl_debug >= 4)
nl_object_dump(obj, &nl_debug_dp);
#endif
if (ops->co_event_filter)
if (ops->co_event_filter(ca->ca_cache, obj) != NL_OK)
return 0;
if (ops->co_include_event)
return ops->co_include_event(ca->ca_cache, obj, ca->ca_change,
ca->ca_change_data);
else
return nl_cache_include(ca->ca_cache, obj, ca->ca_change, ca->ca_change_data);
}
static int event_input(struct nl_msg *msg, void *arg)
{
struct nl_cache_mngr *mngr = arg;
int protocol = nlmsg_get_proto(msg);
int type = nlmsg_hdr(msg)->nlmsg_type;
struct nl_cache_ops *ops;
int i, n;
struct nl_parser_param p = {
.pp_cb = include_cb,
};
NL_DBG(2, "Cache manager %p, handling new message %p as event\n",
mngr, msg);
#ifdef NL_DEBUG
if (nl_debug >= 4)
nl_msg_dump(msg, stderr);
#endif
if (mngr->cm_protocol != protocol)
BUG();
for (i = 0; i < mngr->cm_nassocs; i++) {
if (mngr->cm_assocs[i].ca_cache) {
ops = mngr->cm_assocs[i].ca_cache->c_ops;
for (n = 0; ops->co_msgtypes[n].mt_id >= 0; n++)
if (ops->co_msgtypes[n].mt_id == type)
goto found;
}
}
return NL_SKIP;
found:
NL_DBG(2, "Associated message %p to cache %p\n",
msg, mngr->cm_assocs[i].ca_cache);
p.pp_arg = &mngr->cm_assocs[i];
return nl_cache_parse(ops, NULL, nlmsg_hdr(msg), &p);
}
/**
* Allocate new cache manager
* @arg sk Netlink socket or NULL to auto allocate
* @arg protocol Netlink protocol this manager is used for
* @arg flags Flags (\c NL_AUTO_PROVIDE)
* @arg result Result pointer
*
* Allocates a new cache manager for the specified netlink protocol.
*
* 1. If sk is not specified (\c NULL) a netlink socket matching the
* specified protocol will be automatically allocated.
*
* 2. The socket will be put in non-blocking mode and sequence checking
* will be disabled regardless of whether the socket was provided by
* the caller or automatically allocated.
*
* 3. The socket will be connected.
*
* If the flag \c NL_AUTO_PROVIDE is specified, any cache added to the
* manager will automatically be made available to other users using
* nl_cache_mngt_provide().
*
* @note If the socket is provided by the caller, it is NOT recommended
* to use the socket for anything else besides receiving netlink
* notifications.
*
* @return 0 on success or a negative error code.
*/
int nl_cache_mngr_alloc(struct nl_sock *sk, int protocol, int flags,
struct nl_cache_mngr **result)
{
struct nl_cache_mngr *mngr;
int err = -NLE_NOMEM;
/* Catch abuse of flags */
if (flags & NL_ALLOCATED_SOCK)
BUG();
mngr = calloc(1, sizeof(*mngr));
if (!mngr)
return -NLE_NOMEM;
if (!sk) {
if (!(sk = nl_socket_alloc()))
goto errout;
flags |= NL_ALLOCATED_SOCK;
}
mngr->cm_sock = sk;
mngr->cm_nassocs = NASSOC_INIT;
mngr->cm_protocol = protocol;
mngr->cm_flags = flags;
mngr->cm_assocs = calloc(mngr->cm_nassocs,
sizeof(struct nl_cache_assoc));
if (!mngr->cm_assocs)
goto errout;
/* Required to receive async event notifications */
nl_socket_disable_seq_check(mngr->cm_sock);
if ((err = nl_connect(mngr->cm_sock, protocol)) < 0)
goto errout;
if ((err = nl_socket_set_nonblocking(mngr->cm_sock)) < 0)
goto errout;
/* Create and allocate socket for sync cache fills */
mngr->cm_sync_sock = nl_socket_alloc();
if (!mngr->cm_sync_sock) {
err = -NLE_NOMEM;
goto errout;
}
if ((err = nl_connect(mngr->cm_sync_sock, protocol)) < 0)
goto errout_free_sync_sock;
NL_DBG(1, "Allocated cache manager %p, protocol %d, %d caches\n",
mngr, protocol, mngr->cm_nassocs);
*result = mngr;
return 0;
errout_free_sync_sock:
nl_socket_free(mngr->cm_sync_sock);
errout:
nl_cache_mngr_free(mngr);
return err;
}
/**
* Add cache to cache manager
* @arg mngr Cache manager.
* @arg cache Cache to be added to cache manager
* @arg cb Function to be called upon changes.
* @arg data Argument passed on to change callback
*
* Adds cache to the manager. The operation will trigger a full
* dump request from the kernel to initially fill the contents
* of the cache. The manager will subscribe to the notification group
* of the cache and keep track of any further changes.
*
* The user is responsible for calling nl_cache_mngr_poll() or monitor
* the socket and call nl_cache_mngr_data_ready() to allow the library
* to process netlink notification events.
*
* @see nl_cache_mngr_poll()
* @see nl_cache_mngr_data_ready()
*
* @return 0 on success or a negative error code.
* @return -NLE_PROTO_MISMATCH Protocol mismatch between cache manager and
* cache type
* @return -NLE_OPNOTSUPP Cache type does not support updates
* @return -NLE_EXIST Cache of this type already being managed
*/
int nl_cache_mngr_add_cache(struct nl_cache_mngr *mngr, struct nl_cache *cache,
change_func_t cb, void *data)
{
struct nl_cache_ops *ops;
struct nl_af_group *grp;
int err, i;
ops = cache->c_ops;
if (!ops)
return -NLE_INVAL;
if (ops->co_protocol != mngr->cm_protocol)
return -NLE_PROTO_MISMATCH;
if (ops->co_groups == NULL)
return -NLE_OPNOTSUPP;
for (i = 0; i < mngr->cm_nassocs; i++)
if (mngr->cm_assocs[i].ca_cache &&
mngr->cm_assocs[i].ca_cache->c_ops == ops)
return -NLE_EXIST;
retry:
for (i = 0; i < mngr->cm_nassocs; i++)
if (!mngr->cm_assocs[i].ca_cache)
break;
if (i >= mngr->cm_nassocs) {
mngr->cm_nassocs += NASSOC_EXPAND;
mngr->cm_assocs = realloc(mngr->cm_assocs,
mngr->cm_nassocs *
sizeof(struct nl_cache_assoc));
if (mngr->cm_assocs == NULL)
return -NLE_NOMEM;
memset(mngr->cm_assocs + (mngr->cm_nassocs - NASSOC_EXPAND), 0,
NASSOC_EXPAND * sizeof(struct nl_cache_assoc));
NL_DBG(1, "Increased capacity of cache manager %p " \
"to %d\n", mngr, mngr->cm_nassocs);
goto retry;
}
for (grp = ops->co_groups; grp->ag_group; grp++) {
err = nl_socket_add_membership(mngr->cm_sock, grp->ag_group);
if (err < 0)
return err;
}
err = nl_cache_refill(mngr->cm_sync_sock, cache);
if (err < 0)
goto errout_drop_membership;
mngr->cm_assocs[i].ca_cache = cache;
mngr->cm_assocs[i].ca_change = cb;
mngr->cm_assocs[i].ca_change_data = data;
if (mngr->cm_flags & NL_AUTO_PROVIDE)
nl_cache_mngt_provide(cache);
NL_DBG(1, "Added cache %p <%s> to cache manager %p\n",
cache, nl_cache_name(cache), mngr);
return 0;
errout_drop_membership:
for (grp = ops->co_groups; grp->ag_group; grp++)
nl_socket_drop_membership(mngr->cm_sock, grp->ag_group);
return err;
}
/**
* Add cache to cache manager
* @arg mngr Cache manager.
* @arg name Name of cache to keep track of
* @arg cb Function to be called upon changes.
* @arg data Argument passed on to change callback
* @arg result Pointer to store added cache (optional)
*
* Allocates a new cache of the specified type and adds it to the manager.
* The operation will trigger a full dump request from the kernel to
* initially fill the contents of the cache. The manager will subscribe
* to the notification group of the cache and keep track of any further
* changes.
*
* The user is responsible for calling nl_cache_mngr_poll() or monitor
* the socket and call nl_cache_mngr_data_ready() to allow the library
* to process netlink notification events.
*
* @see nl_cache_mngr_poll()
* @see nl_cache_mngr_data_ready()
*
* @return 0 on success or a negative error code.
* @return -NLE_NOCACHE Unknown cache type
* @return -NLE_PROTO_MISMATCH Protocol mismatch between cache manager and
* cache type
* @return -NLE_OPNOTSUPP Cache type does not support updates
* @return -NLE_EXIST Cache of this type already being managed
*/
int nl_cache_mngr_add(struct nl_cache_mngr *mngr, const char *name,
change_func_t cb, void *data, struct nl_cache **result)
{
struct nl_cache_ops *ops;
struct nl_cache *cache;
int err;
ops = nl_cache_ops_lookup_safe(name);
if (!ops)
return -NLE_NOCACHE;
cache = nl_cache_alloc(ops);
nl_cache_ops_put(ops);
if (!cache)
return -NLE_NOMEM;
err = nl_cache_mngr_add_cache(mngr, cache, cb, data);
if (err < 0)
goto errout_free_cache;
*result = cache;
return 0;
errout_free_cache:
nl_cache_free(cache);
return err;
}
/**
* Get socket file descriptor
* @arg mngr Cache Manager
*
* Get the file descriptor of the socket associated with the manager.
*
* @note Do not use the socket for anything besides receiving
* notifications.
*/
int nl_cache_mngr_get_fd(struct nl_cache_mngr *mngr)
{
return nl_socket_get_fd(mngr->cm_sock);
}
/**
* Check for event notifications
* @arg mngr Cache Manager
* @arg timeout Upper limit poll() will block, in milliseconds.
*
* Causes poll() to be called to check for new event notifications
* being available. Calls nl_cache_mngr_data_ready() to process
* available data.
*
* This functionally is ideally called regularly during an idle
* period.
*
* A timeout can be specified in milliseconds to limit the time the
* function will wait for updates.
*
* @see nl_cache_mngr_data_ready()
*
* @return The number of messages processed or a negative error code.
*/
int nl_cache_mngr_poll(struct nl_cache_mngr *mngr, int timeout)
{
int ret;
struct pollfd fds = {
.fd = nl_socket_get_fd(mngr->cm_sock),
.events = POLLIN,
};
NL_DBG(3, "Cache manager %p, poll() fd %d\n", mngr, fds.fd);
ret = poll(&fds, 1, timeout);
NL_DBG(3, "Cache manager %p, poll() returned %d\n", mngr, ret);
if (ret < 0)
return -nl_syserr2nlerr(errno);
/* No events, return */
if (ret == 0)
return 0;
return nl_cache_mngr_data_ready(mngr);
}
/**
* Receive available event notifications
* @arg mngr Cache manager
*
* This function can be called if the socket associated to the manager
* contains updates to be received. This function should only be used
* if nl_cache_mngr_poll() is not used.
*
* The function will process messages until there is no more data to
* be read from the socket.
*
* @see nl_cache_mngr_poll()
*
* @return The number of messages processed or a negative error code.
*/
int nl_cache_mngr_data_ready(struct nl_cache_mngr *mngr)
{
int err, nread = 0;
struct nl_cb *cb;
NL_DBG(2, "Cache manager %p, reading new data from fd %d\n",
mngr, nl_socket_get_fd(mngr->cm_sock));
cb = nl_cb_clone(mngr->cm_sock->s_cb);
if (cb == NULL)
return -NLE_NOMEM;
nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, event_input, mngr);
while ((err = nl_recvmsgs_report(mngr->cm_sock, cb)) > 0) {
NL_DBG(2, "Cache manager %p, recvmsgs read %d messages\n",
mngr, err);
nread += err;
}
nl_cb_put(cb);
if (err < 0 && err != -NLE_AGAIN)
return err;
return nread;
}
/**
* Print information about cache manager
* @arg mngr Cache manager
* @arg p Dumping parameters
*
* Prints information about the cache manager including all managed caches.
*
* @note This is a debugging function.
*/
void nl_cache_mngr_info(struct nl_cache_mngr *mngr, struct nl_dump_params *p)
{
char buf[128];
int i;
nl_dump_line(p, "cache-manager <%p>\n", mngr);
nl_dump_line(p, " .protocol = %s\n",
nl_nlfamily2str(mngr->cm_protocol, buf, sizeof(buf)));
nl_dump_line(p, " .flags = %#x\n", mngr->cm_flags);
nl_dump_line(p, " .nassocs = %u\n", mngr->cm_nassocs);
nl_dump_line(p, " .sock = <%p>\n", mngr->cm_sock);
for (i = 0; i < mngr->cm_nassocs; i++) {
struct nl_cache_assoc *assoc = &mngr->cm_assocs[i];
if (assoc->ca_cache) {
nl_dump_line(p, " .cache[%d] = <%p> {\n", i, assoc->ca_cache);
nl_dump_line(p, " .name = %s\n", assoc->ca_cache->c_ops->co_name);
nl_dump_line(p, " .change_func = <%p>\n", assoc->ca_change);
nl_dump_line(p, " .change_data = <%p>\n", assoc->ca_change_data);
nl_dump_line(p, " .nitems = %u\n", nl_cache_nitems(assoc->ca_cache));
nl_dump_line(p, " .objects = {\n");
p->dp_prefix += 6;
nl_cache_dump(assoc->ca_cache, p);
p->dp_prefix -= 6;
nl_dump_line(p, " }\n");
nl_dump_line(p, " }\n");
}
}
}
/**
* Free cache manager and all caches.
* @arg mngr Cache manager.
*
* Release all resources held by a cache manager.
*/
void nl_cache_mngr_free(struct nl_cache_mngr *mngr)
{
int i;
if (!mngr)
return;
if (mngr->cm_sock)
nl_close(mngr->cm_sock);
if (mngr->cm_sync_sock) {
nl_close(mngr->cm_sync_sock);
nl_socket_free(mngr->cm_sync_sock);
}
if (mngr->cm_flags & NL_ALLOCATED_SOCK)
nl_socket_free(mngr->cm_sock);
for (i = 0; i < mngr->cm_nassocs; i++) {
if (mngr->cm_assocs[i].ca_cache) {
nl_cache_mngt_unprovide(mngr->cm_assocs[i].ca_cache);
nl_cache_free(mngr->cm_assocs[i].ca_cache);
}
}
free(mngr->cm_assocs);
NL_DBG(1, "Cache manager %p freed\n", mngr);
free(mngr);
}
/** @} */