netfilter: sysctl support of logger choice
authorEric Leblond <eric@inl.fr>
Mon, 23 Mar 2009 12:16:53 +0000 (13:16 +0100)
committerPatrick McHardy <kaber@trash.net>
Mon, 23 Mar 2009 12:16:53 +0000 (13:16 +0100)
This patchs adds support of modification of the used logger via sysctl.
It can be used to change the logger to module that can not use the bind
operation (ipt_LOG and ipt_ULOG). For this purpose, it creates a
directory /proc/sys/net/netfilter/nf_log which contains a file
per-protocol. The content of the file is the name current logger (NONE if
not set) and a logger can be setup by simply echoing its name to the file.
By echoing "NONE" to a /proc/sys/net/netfilter/nf_log/PROTO file, the
logger corresponding to this PROTO is set to NULL.

Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>
net/netfilter/nf_log.c

index 4fcbcc71aa32e4597da8b57f6a5664139be6b246..8bb998fe098b0d3afe1815f021f0913822fe3b9a 100644 (file)
@@ -14,6 +14,7 @@
    LOG target modules */
 
 #define NF_LOG_PREFIXLEN               128
+#define NFLOGGER_NAME_LEN              64
 
 static const struct nf_logger *nf_loggers[NFPROTO_NUMPROTO] __read_mostly;
 static struct list_head nf_loggers_l[NFPROTO_NUMPROTO] __read_mostly;
@@ -207,18 +208,100 @@ static const struct file_operations nflog_file_ops = {
        .release = seq_release,
 };
 
+
 #endif /* PROC_FS */
 
+#ifdef CONFIG_SYSCTL
+struct ctl_path nf_log_sysctl_path[] = {
+       { .procname = "net", .ctl_name = CTL_NET, },
+       { .procname = "netfilter", .ctl_name = NET_NETFILTER, },
+       { .procname = "nf_log", .ctl_name = CTL_UNNUMBERED, },
+       { }
+};
+
+static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
+static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
+static struct ctl_table_header *nf_log_dir_header;
 
-int __init netfilter_log_init(void)
+static int nf_log_proc_dostring(ctl_table *table, int write, struct file *filp,
+                        void *buffer, size_t *lenp, loff_t *ppos)
+{
+       const struct nf_logger *logger;
+       int r = 0;
+       int tindex = (unsigned long)table->extra1;
+
+       if (write) {
+               if (!strcmp(buffer, "NONE")) {
+                       nf_log_unbind_pf(tindex);
+                       return 0;
+               }
+               mutex_lock(&nf_log_mutex);
+               logger = __find_logger(tindex, buffer);
+               if (logger == NULL) {
+                       mutex_unlock(&nf_log_mutex);
+                       return -ENOENT;
+               }
+               rcu_assign_pointer(nf_loggers[tindex], logger);
+               mutex_unlock(&nf_log_mutex);
+       } else {
+               rcu_read_lock();
+               logger = rcu_dereference(nf_loggers[tindex]);
+               if (!logger)
+                       table->data = "NONE";
+               else
+                       table->data = logger->name;
+               r = proc_dostring(table, write, filp, buffer, lenp, ppos);
+               rcu_read_unlock();
+       }
+
+       return r;
+}
+
+static __init int netfilter_log_sysctl_init(void)
 {
        int i;
+
+       for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++) {
+               snprintf(nf_log_sysctl_fnames[i-NFPROTO_UNSPEC], 3, "%d", i);
+               nf_log_sysctl_table[i].ctl_name = CTL_UNNUMBERED;
+               nf_log_sysctl_table[i].procname =
+                       nf_log_sysctl_fnames[i-NFPROTO_UNSPEC];
+               nf_log_sysctl_table[i].data = NULL;
+               nf_log_sysctl_table[i].maxlen =
+                       NFLOGGER_NAME_LEN * sizeof(char);
+               nf_log_sysctl_table[i].mode = 0644;
+               nf_log_sysctl_table[i].proc_handler = nf_log_proc_dostring;
+               nf_log_sysctl_table[i].extra1 = (void *)(unsigned long) i;
+       }
+
+       nf_log_dir_header = register_sysctl_paths(nf_log_sysctl_path,
+                                      nf_log_sysctl_table);
+       if (!nf_log_dir_header)
+               return -ENOMEM;
+
+       return 0;
+}
+#else
+static __init int netfilter_log_sysctl_init(void)
+{
+       return 0;
+}
+#endif /* CONFIG_SYSCTL */
+
+int __init netfilter_log_init(void)
+{
+       int i, r;
 #ifdef CONFIG_PROC_FS
        if (!proc_create("nf_log", S_IRUGO,
                         proc_net_netfilter, &nflog_file_ops))
                return -1;
 #endif
 
+       /* Errors will trigger panic, unroll on error is unnecessary. */
+       r = netfilter_log_sysctl_init();
+       if (r < 0)
+               return r;
+
        for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
                INIT_LIST_HEAD(&(nf_loggers_l[i]));