// SPDX-License-Identifier: GPL-2.0-only
/*
* This is a module which is used for logging packets to userspace via
* nfetlink.
*
* (C) 2005 by Harald Welte <laforge@netfilter.org>
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*
* Based on the old ipv4-only ipt_ULOG.c:
* (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/netfilter_bridge.h>
#include <net/netlink.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_log.h>
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/spinlock.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/netfilter/nf_log.h>
#include <net/netns/generic.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
#include "../bridge/br_private.h"
#endif
#define NFULNL_COPY_DISABLED 0xff
#define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
#define NFULNL_TIMEOUT_DEFAULT 100 /* every second */
#define NFULNL_QTHRESH_DEFAULT 100 /* 100 packets */
/* max packet size is limited by 16-bit struct nfattr nfa_len field */
#define NFULNL_COPY_RANGE_MAX (0xFFFF - NLA_HDRLEN)
#define PRINTR(x, args...) do { if (net_ratelimit()) \
printk(x, ## args); } while (0);
struct nfulnl_instance {
struct hlist_node hlist; /* global list of instances */
spinlock_t lock;
refcount_t use; /* use count */
unsigned int qlen; /* number of nlmsgs in skb */
struct sk_buff *skb; /* pre-allocatd skb */
struct timer_list timer;
struct net *net;
struct user_namespace *peer_user_ns; /* User namespace of the peer process */
u32 peer_portid; /* PORTID of the peer process */
/* configurable parameters */
unsigned int flushtimeout; /* timeout until queue flush */
unsigned int nlbufsiz; /* netlink buffer allocation size */
unsigned int qthreshold; /* threshold of the queue */
u_int32_t copy_range;
u_int32_t seq; /* instance-local sequential counter */
u_int16_t group_num; /* number of this queue */
u_int16_t flags;
u_int8_t copy_mode;
struct rcu_head rcu;
};
#define INSTANCE_BUCKETS 16
static unsigned int nfnl_log_net_id __read_mostly;
struct nfnl_log_net {
spinlock_t instances_lock;
struct hlist_head instance_table[INSTANCE_BUCKETS];
atomic_t global_seq;
};
static struct nfnl_log_net *nfnl_log_pernet(struct net *net)
{
return net_generic(net, nfnl_log_net_id);
}
static inline u_int8_t instance_hashfn(u_int16_t group_num)
{
return ((group_num & 0xff) % INSTANCE_BUCKETS);
}
static struct nfulnl_instance *
__instance_lookup(struct nfnl_log_net *log, u_int16_t group_num)
{
struct hlist_head *head;
struct nfulnl_instance *inst;
head = &log->instance_table[instance_hashfn(group_num)];
hlist_for_each_entry_rcu(inst, head, hlist) {
if (inst->group_num == group_num)
return inst;
}
return NULL;
}
static inline void
instance_get(struct nfulnl_instance *inst)
{
refcount_inc(&inst->use);
}
static struct nfulnl_instance *
instance_lookup_get(struct nfnl_log_net *log, u_int16_t group_num)
{
struct nfulnl_instance *inst;
rcu_read_lock_bh();
inst = __instance_lookup(log, group_num);
if (inst && !refcount_inc_not_zero(&inst->use))
inst = NULL;
rcu_read_unlock_bh();
return inst;
}
static void nfulnl_instance_free_rcu(struct rcu_head *head)
{
struct nfulnl_instance *inst =
container_of(head, struct nfulnl_instance, rcu);
put_net(inst->net);
kfree(inst);
module_put(THIS_MODULE);
}
static void