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// SPDX-License-Identifier: GPL-2.0-or-later
/* Structure dynamic extension infrastructure
* Copyright (C) 2004 Rusty Russell IBM Corporation
* Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
*/
#include <linux/kernel.h>
#include <linux/kmemleak.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_acct.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_conntrack_timestamp.h>
#include <net/netfilter/nf_conntrack_timeout.h>
#include <net/netfilter/nf_conntrack_labels.h>
#include <net/netfilter/nf_conntrack_synproxy.h>
#include <net/netfilter/nf_conntrack_act_ct.h>
#include <net/netfilter/nf_nat.h>
#define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */
atomic_t nf_conntrack_ext_genid __read_mostly = ATOMIC_INIT(1);
static const u8 nf_ct_ext_type_len[NF_CT_EXT_NUM] = {
[NF_CT_EXT_HELPER] = sizeof(struct nf_conn_help),
#if IS_ENABLED(CONFIG_NF_NAT)
[NF_CT_EXT_NAT] = sizeof(struct nf_conn_nat),
#endif
[NF_CT_EXT_SEQADJ] = sizeof(struct nf_conn_seqadj),
[NF_CT_EXT_ACCT] = sizeof(struct nf_conn_acct),
#ifdef CONFIG_NF_CONNTRACK_EVENTS
[NF_CT_EXT_ECACHE] = sizeof(struct nf_conntrack_ecache),
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
[NF_CT_EXT_TSTAMP] = sizeof(struct nf_conn_acct),
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
[NF_CT_EXT_TIMEOUT] = sizeof(struct nf_conn_tstamp),
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
[NF_CT_EXT_LABELS] = sizeof(struct nf_conn_labels),
#endif
#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
[NF_CT_EXT_SYNPROXY] = sizeof(struct nf_conn_synproxy),
#endif
#if IS_ENABLED(CONFIG_NET_ACT_CT)
[NF_CT_EXT_ACT_CT] = sizeof(struct nf_conn_act_ct_ext),
#endif
};
static __always_inline unsigned int total_extension_size(void)
{
/* remember to add new extensions below */
BUILD_BUG_ON(NF_CT_EXT_NUM > 10);
return sizeof(struct nf_ct_ext) +
sizeof(struct nf_conn_help)
#if IS_ENABLED(CONFIG_NF_NAT)
+ sizeof(struct nf_conn_nat)
#endif
+ sizeof(struct nf_conn_seqadj)
+ sizeof(struct nf_conn_acct)
#ifdef CONFIG_NF_CONNTRACK_EVENTS
+ sizeof(struct nf_conntrack_ecache)
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
+ sizeof(struct nf_conn_tstamp)
#endif
#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
+ sizeof(struct nf_conn_timeout)
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
+ sizeof(struct nf_conn_labels)
#endif
#if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
+ sizeof(struct nf_conn_synproxy)
#endif
#if IS_ENABLED(CONFIG_NET_ACT_CT)
+ sizeof(struct nf_conn_act_ct_ext)
#endif
;
}
void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
{
unsigned int newlen, newoff, oldlen, alloc;
struct nf_ct_ext *new;
/* Conntrack must not be confirmed to avoid races on reallocation. */
WARN_ON(nf_ct_is_confirmed(ct));
/* struct nf_ct_ext uses u8 to store offsets/size */
BUILD_BUG_ON(total_extension_size() > 255u);
if (ct->ext) {
const struct nf_ct_ext *old = ct->ext;
if (__nf_ct_ext_exist(old, id))
return NULL;
oldlen = old->len;
} else {
oldlen = sizeof(*new);
}
newoff = ALIGN(oldlen, __alignof__(struct nf_ct_ext));
newlen = newoff + nf_ct_ext_type_len[id];
alloc = max(newlen, NF_CT_EXT_PREALLOC);
new = krealloc(ct->ext, alloc, gfp);
if (!new)
return NULL;
if (!ct->ext) {
memset(new->offset, 0, sizeof(new->offset));
new->gen_id = atomic_read(&nf_conntrack_ext_genid);
}
new->offset[id] = newoff;
new->len = newlen;
memset((void *)new + newoff, 0, newlen - newoff);
ct->ext = new;
return (void *)new + newoff;
}
EXPORT_SYMBOL(nf_ct_ext_add);
/* Use nf_ct_ext_find wrapper. This is only useful for unconfirmed entries. */
void *__nf_ct_ext_find(const struct nf_ct_ext *ext, u8 id)
{
unsigned int gen_id = atomic_read(&nf_conntrack_ext_genid);
unsigned int this_id = READ_ONCE(ext->gen_id);
if (!__nf_ct_ext_exist(ext, id))
return NULL;
if (this_id == 0 || ext->gen_id == gen_id)
return (void *)ext + ext->offset[id];
return NULL;
}
EXPORT_SYMBOL(__nf_ct_ext_find);
void nf_ct_ext_bump_genid(void)
{
unsigned int value = atomic_inc_return(&nf_conntrack_ext_genid);
if (value == UINT_MAX)
atomic_set(&nf_conntrack_ext_genid, 1);
msleep(HZ);
}
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