// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter.h>
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#include <linux/mutex.h>
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#include <net/sock.h>
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#include "nf_internals.h"
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/* Sockopts only registered and called from user context, so
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net locking would be overkill. Also, [gs]etsockopt calls may
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sleep. */
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static DEFINE_MUTEX(nf_sockopt_mutex);
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static LIST_HEAD(nf_sockopts);
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/* Do exclusive ranges overlap? */
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static inline int overlap(int min1, int max1, int min2, int max2)
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{
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return max1 > min2 && min1 < max2;
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}
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/* Functions to register sockopt ranges (exclusive). */
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int nf_register_sockopt(struct nf_sockopt_ops *reg)
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{
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struct nf_sockopt_ops *ops;
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int ret = 0;
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mutex_lock(&nf_sockopt_mutex);
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list_for_each_entry(ops, &nf_sockopts, list) {
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if (ops->pf == reg->pf
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&& (overlap(ops->set_optmin, ops->set_optmax,
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reg->set_optmin, reg->set_optmax)
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|| overlap(ops->get_optmin, ops->get_optmax,
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reg->get_optmin, reg->get_optmax))) {
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pr_debug("nf_sock overlap: %u-%u/%u-%u v %u-%u/%u-%u\n",
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ops->set_optmin, ops->set_optmax,
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ops->get_optmin, ops->get_optmax,
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reg->set_optmin, reg->set_optmax,
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reg->get_optmin, reg->get_optmax);
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ret = -EBUSY;
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goto out;
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}
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}
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list_add(®->list, &nf_sockopts);
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out:
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mutex_unlock(&nf_sockopt_mutex);
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return ret;
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}
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EXPORT_SYMBOL(nf_register_sockopt);
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void nf_unregister_sockopt(struct nf_sockopt_ops *reg)
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{
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mutex_lock(&nf_sockopt_mutex);
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list_del(®->list);
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mutex_unlock(&nf_sockopt_mutex);
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}
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EXPORT_SYMBOL(nf_unregister_sockopt);
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static struct nf_sockopt_ops *nf_sockopt_find(struct sock *sk, u_int8_t pf,
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int val, int get)
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{
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struct nf_sockopt_ops *ops;
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mutex_lock(&nf_sockopt_mutex);
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list_for_each_entry(ops, &nf_sockopts, list) {
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if (ops->pf == pf) {
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if (!try_module_get(ops->owner))
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goto out_nosup;
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if (get) {
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if (val >= ops->get_optmin &&
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val < ops->get_optmax)
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goto out;
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} else {
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if (val >= ops->set_optmin &&
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val < ops->set_optmax)
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goto out;
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}
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module_put(ops->owner);
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}
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}
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out_nosup:
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ops = ERR_PTR(-ENOPROTOOPT);
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out:
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mutex_unlock(&nf_sockopt_mutex);
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return ops;
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}
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int nf_setsockopt(struct sock *sk, u_int8_t pf, int val, sockptr_t opt,
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unsigned int len)
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{
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struct nf_sockopt_ops *ops;
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int ret;
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ops = nf_sockopt_find(sk, pf, val, 0);
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if (IS_ERR(ops))
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return PTR_ERR(ops);
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ret = ops->set(sk, val, opt, len);
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module_put(ops->owner);
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return ret;
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}
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EXPORT_SYMBOL(nf_setsockopt);
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int nf_getsockopt(struct sock *sk, u_int8_t pf, int val, char __user *opt,
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int *len)
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{
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struct nf_sockopt_ops *ops;
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int ret;
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ops = nf_sockopt_find(sk, pf, val, 1);
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if (IS_ERR(ops))
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return PTR_ERR(ops);
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ret = ops->get(sk, val, opt, len);
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module_put(ops->owner);
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return ret;
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}
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EXPORT_SYMBOL(nf_getsockopt);
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