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);
+