netfilter: use a linked list of loggers
This patch modifies nf_log to use a linked list of loggers for each
protocol. This list of loggers is read and write protected with a
mutex.
This patch separates registration and binding. To be used as
logging module, a module has to register calling nf_log_register()
and to bind to a protocol it has to call nf_log_bind_pf().
This patch also converts the logging modules to the new API. For nfnetlink_log,
it simply switchs call to register functions to call to bind function and
adds a call to nf_log_register() during init. For other modules, it just
remove a const flag from the logger structure and replace it with a
__read_mostly.
Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index fa8ae5d..a228b5f 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -16,56 +16,60 @@
#define NF_LOG_PREFIXLEN 128
static const struct nf_logger *nf_loggers[NFPROTO_NUMPROTO] __read_mostly;
+static struct list_head nf_loggers_l[NFPROTO_NUMPROTO] __read_mostly;
static DEFINE_MUTEX(nf_log_mutex);
-/* return EBUSY if somebody else is registered, EEXIST if the same logger
- * is registred, 0 on success. */
-int nf_log_register(u_int8_t pf, const struct nf_logger *logger)
+static struct nf_logger *__find_logger(int pf, const char *str_logger)
{
- int ret;
+ struct nf_logger *t;
+
+ list_for_each_entry(t, &nf_loggers_l[pf], list[pf]) {
+ if (!strnicmp(str_logger, t->name, strlen(t->name)))
+ return t;
+ }
+
+ return NULL;
+}
+
+/* return EEXIST if the same logger is registred, 0 on success. */
+int nf_log_register(u_int8_t pf, struct nf_logger *logger)
+{
+ const struct nf_logger *llog;
if (pf >= ARRAY_SIZE(nf_loggers))
return -EINVAL;
- /* Any setup of logging members must be done before
- * substituting pointer. */
- ret = mutex_lock_interruptible(&nf_log_mutex);
- if (ret < 0)
- return ret;
+ mutex_lock(&nf_log_mutex);
- if (!nf_loggers[pf])
- rcu_assign_pointer(nf_loggers[pf], logger);
- else if (nf_loggers[pf] == logger)
- ret = -EEXIST;
- else
- ret = -EBUSY;
+ if (pf == NFPROTO_UNSPEC) {
+ int i;
+ for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
+ list_add_tail(&(logger->list[i]), &(nf_loggers_l[i]));
+ } else {
+ /* register at end of list to honor first register win */
+ list_add_tail(&logger->list[pf], &nf_loggers_l[pf]);
+ llog = rcu_dereference(nf_loggers[pf]);
+ if (llog == NULL)
+ rcu_assign_pointer(nf_loggers[pf], logger);
+ }
mutex_unlock(&nf_log_mutex);
- return ret;
+
+ return 0;
}
EXPORT_SYMBOL(nf_log_register);
-void nf_log_unregister_pf(u_int8_t pf)
+void nf_log_unregister(struct nf_logger *logger)
{
- if (pf >= ARRAY_SIZE(nf_loggers))
- return;
- mutex_lock(&nf_log_mutex);
- rcu_assign_pointer(nf_loggers[pf], NULL);
- mutex_unlock(&nf_log_mutex);
-
- /* Give time to concurrent readers. */
- synchronize_rcu();
-}
-EXPORT_SYMBOL(nf_log_unregister_pf);
-
-void nf_log_unregister(const struct nf_logger *logger)
-{
+ const struct nf_logger *c_logger;
int i;
mutex_lock(&nf_log_mutex);
for (i = 0; i < ARRAY_SIZE(nf_loggers); i++) {
- if (nf_loggers[i] == logger)
+ c_logger = rcu_dereference(nf_loggers[i]);
+ if (c_logger == logger)
rcu_assign_pointer(nf_loggers[i], NULL);
+ list_del(&logger->list[i]);
}
mutex_unlock(&nf_log_mutex);
@@ -73,6 +77,27 @@
}
EXPORT_SYMBOL(nf_log_unregister);
+int nf_log_bind_pf(u_int8_t pf, const struct nf_logger *logger)
+{
+ mutex_lock(&nf_log_mutex);
+ if (__find_logger(pf, logger->name) == NULL) {
+ mutex_unlock(&nf_log_mutex);
+ return -ENOENT;
+ }
+ rcu_assign_pointer(nf_loggers[pf], logger);
+ mutex_unlock(&nf_log_mutex);
+ return 0;
+}
+EXPORT_SYMBOL(nf_log_bind_pf);
+
+void nf_log_unbind_pf(u_int8_t pf)
+{
+ mutex_lock(&nf_log_mutex);
+ rcu_assign_pointer(nf_loggers[pf], NULL);
+ mutex_unlock(&nf_log_mutex);
+}
+EXPORT_SYMBOL(nf_log_unbind_pf);
+
void nf_log_packet(u_int8_t pf,
unsigned int hooknum,
const struct sk_buff *skb,
@@ -163,10 +188,15 @@
int __init netfilter_log_init(void)
{
+ int i;
#ifdef CONFIG_PROC_FS
if (!proc_create("nf_log", S_IRUGO,
proc_net_netfilter, &nflog_file_ops))
return -1;
#endif
+
+ for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
+ INIT_LIST_HEAD(&(nf_loggers_l[i]));
+
return 0;
}