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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter.h>
#include <linux/mutex.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 DEFINE_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 nf_sockopt_ops *ops;
int ret = 0;
mutex_lock(&nf_sockopt_mutex);
list_for_each_entry(ops, &nf_sockopts, list) {
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))) {
pr_debug("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(®->list, &nf_sockopts);
out:
mutex_unlock(&nf_sockopt_mutex);
return ret;
}
EXPORT_SYMBOL(nf_register_sockopt);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
{
mutex_lock(&nf_sockopt_mutex);
list_del(®->list);
mutex_unlock(&nf_sockopt_mutex);
}
EXPORT_SYMBOL(nf_unregister_sockopt);
static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
int val, int get)
{
struct nf_sockopt_ops *ops;
mutex_lock(&nf_sockopt_mutex);
list_for_each_entry(ops, &nf_sockopts, list) {
if (ops->pf == pf) {
if (!try_module_get(ops->owner))
goto out_nosup;
if (get) {
if (val >= ops->get_optmin &&
val < ops->get_optmax)
goto out;
} else {
if (val >= ops->set_optmin &&
val < ops->set_optmax)
goto out;
}
module_put(ops->owner);
}
}
out_nosup:
ops = ERR_PTR(-ENOPROTOOPT);
out:
mutex_unlock(&nf_sockopt_mutex);
return ops;
}
int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, sockptr_t opt,
unsigned int len)
{
struct nf_sockopt_ops *ops;
int ret;
ops = nf_sockopt_find(sk, pf, val, 0);
if (IS_ERR(ops))
return PTR_ERR(ops);
ret = ops->set(sk, val, opt, len);
module_put(ops->owner);
return ret;
}
EXPORT_SYMBOL(nf_setsockopt);
int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
int *len)
{
struct nf_sockopt_ops *ops;
int ret;
ops = nf_sockopt_find(sk, pf, val, 1);
if (IS_ERR(ops))
return PTR_ERR(ops);
ret = ops->get(sk, val, opt, len);
module_put(ops->owner);
return ret;
}
EXPORT_SYMBOL(nf_getsockopt);
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