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path: root/net/netfilter/nf_sockopt.c
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Diffstat (limited to 'net/netfilter/nf_sockopt.c')
-rw-r--r--net/netfilter/nf_sockopt.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/net/netfilter/nf_sockopt.c b/net/netfilter/nf_sockopt.c
new file mode 100644
index 00000000000..61a833a9caa
--- /dev/null
+++ b/net/netfilter/nf_sockopt.c
@@ -0,0 +1,132 @@
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <net/sock.h>
+
+#include "nf_internals.h"
+
+/* Sockopts only registered and called from user context, so
+ net locking would be overkill. Also, [gs]etsockopt calls may
+ sleep. */
+static DECLARE_MUTEX(nf_sockopt_mutex);
+static LIST_HEAD(nf_sockopts);
+
+/* Do exclusive ranges overlap? */
+static inline int overlap(int min1, int max1, int min2, int max2)
+{
+ return max1 > min2 && min1 < max2;
+}
+
+/* Functions to register sockopt ranges (exclusive). */
+int nf_register_sockopt(struct nf_sockopt_ops *reg)
+{
+ struct list_head *i;
+ int ret = 0;
+
+ if (down_interruptible(&nf_sockopt_mutex) != 0)
+ return -EINTR;
+
+ list_for_each(i, &nf_sockopts) {
+ struct nf_sockopt_ops *ops = (struct nf_sockopt_ops *)i;
+ if (ops->pf == reg->pf
+ && (overlap(ops->set_optmin, ops->set_optmax,
+ reg->set_optmin, reg->set_optmax)
+ || overlap(ops->get_optmin, ops->get_optmax,
+ reg->get_optmin, reg->get_optmax))) {
+ NFDEBUG("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
+ ops->set_optmin, ops->set_optmax,
+ ops->get_optmin, ops->get_optmax,
+ reg->set_optmin, reg->set_optmax,
+ reg->get_optmin, reg->get_optmax);
+ ret = -EBUSY;
+ goto out;
+ }
+ }
+
+ list_add(&reg->list, &nf_sockopts);
+out:
+ up(&nf_sockopt_mutex);
+ return ret;
+}
+EXPORT_SYMBOL(nf_register_sockopt);
+
+void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
+{
+ /* No point being interruptible: we're probably in cleanup_module() */
+ restart:
+ down(&nf_sockopt_mutex);
+ if (reg->use != 0) {
+ /* To be woken by nf_sockopt call... */
+ /* FIXME: Stuart Young's name appears gratuitously. */
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ reg->cleanup_task = current;
+ up(&nf_sockopt_mutex);
+ schedule();
+ goto restart;
+ }
+ list_del(&reg->list);
+ up(&nf_sockopt_mutex);
+}
+EXPORT_SYMBOL(nf_unregister_sockopt);
+
+/* Call get/setsockopt() */
+static int nf_sockopt(struct sock *sk, int pf, int val,
+ char __user *opt, int *len, int get)
+{
+ struct list_head *i;
+ struct nf_sockopt_ops *ops;
+ int ret;
+
+ if (down_interruptible(&nf_sockopt_mutex) != 0)
+ return -EINTR;
+
+ list_for_each(i, &nf_sockopts) {
+ ops = (struct nf_sockopt_ops *)i;
+ if (ops->pf == pf) {
+ if (get) {
+ if (val >= ops->get_optmin
+ && val < ops->get_optmax) {
+ ops->use++;
+ up(&nf_sockopt_mutex);
+ ret = ops->get(sk, val, opt, len);
+ goto out;
+ }
+ } else {
+ if (val >= ops->set_optmin
+ && val < ops->set_optmax) {
+ ops->use++;
+ up(&nf_sockopt_mutex);
+ ret = ops->set(sk, val, opt, *len);
+ goto out;
+ }
+ }
+ }
+ }
+ up(&nf_sockopt_mutex);
+ return -ENOPROTOOPT;
+
+ out:
+ down(&nf_sockopt_mutex);
+ ops->use--;
+ if (ops->cleanup_task)
+ wake_up_process(ops->cleanup_task);
+ up(&nf_sockopt_mutex);
+ return ret;
+}
+
+int nf_setsockopt(struct sock *sk, int pf, int val, char __user *opt,
+ int len)
+{
+ return nf_sockopt(sk, pf, val, opt, &len, 0);
+}
+EXPORT_SYMBOL(nf_setsockopt);
+
+int nf_getsockopt(struct sock *sk, int pf, int val, char __user *opt, int *len)
+{
+ return nf_sockopt(sk, pf, val, opt, len, 1);
+}
+EXPORT_SYMBOL(nf_getsockopt);
+