// 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
  instance_put(struct nfulnl_instance *inst)
  {

  	if (inst && refcount_dec_and_test(&inst->use))

  		call_rcu(&inst->rcu, nfulnl_instance_free_rcu);

  }

  static void nfulnl_timer(struct timer_list *t);

  
  static struct nfulnl_instance *

  instance_create(struct net *net, u_int16_t group_num,

  		u32 portid, struct user_namespace *user_ns)

  {
  	struct nfulnl_instance *inst;

  	struct nfnl_log_net *log = nfnl_log_pernet(net);

  	int err;

  	spin_lock_bh(&log->instances_lock);
  	if (__instance_lookup(log, group_num)) {

  		err = -EEXIST;

  		goto out_unlock;
  	}

  	inst = kzalloc(sizeof(*inst), GFP_ATOMIC);

  	if (!inst) {
  		err = -ENOMEM;

  		goto out_unlock;

  	}

  	if (!try_module_get(THIS_MODULE)) {
  		kfree(inst);

  		err = -EAGAIN;

  		goto out_unlock;
  	}

  	INIT_HLIST_NODE(&inst->hlist);

  	spin_lock_init(&inst->lock);

  	/* needs to be two, since we _put() after creation */

  	refcount_set(&inst->use, 2);

  	timer_setup(&inst->timer, nfulnl_timer, 0);

  	inst->net = get_net(net);

  	inst->peer_user_ns = user_ns;

  	inst->peer_portid = portid;

  	inst->group_num = group_num;
  
  	inst->qthreshold 	= NFULNL_QTHRESH_DEFAULT;
  	inst->flushtimeout 	= NFULNL_TIMEOUT_DEFAULT;
  	inst->nlbufsiz 		= NFULNL_NLBUFSIZ_DEFAULT;
  	inst->copy_mode 	= NFULNL_COPY_PACKET;

  	inst->copy_range 	= NFULNL_COPY_RANGE_MAX;

  	hlist_add_head_rcu(&inst->hlist,

  		       &log->instance_table[instance_hashfn(group_num)]);

  	spin_unlock_bh(&log->instances_lock);

  
  	return inst;

  out_unlock:

  	spin_unlock_bh(&log->instances_lock);

  	return ERR_PTR(err);

  }

  static void __nfulnl_flush(struct nfulnl_instance *inst);

  /* called with BH disabled */

  static void

  __instance_destroy(struct nfulnl_instance *inst)

  {
  	/* first pull it out of the global list */

  	hlist_del_rcu(&inst->hlist);

  	/* then flush all pending packets from skb */

  	spin_lock(&inst->lock);
  
  	/* lockless readers wont be able to use us */
  	inst->copy_mode = NFULNL_COPY_DISABLED;

  	if (inst->skb)
  		__nfulnl_flush(inst);

  	spin_unlock(&inst->lock);

  
  	/* and finally put the refcount */
  	instance_put(inst);

  }
  
  static inline void

  instance_destroy(struct nfnl_log_net *log,
  		 struct nfulnl_instance *inst)

  {

  	spin_lock_bh(&log->instances_lock);

  	__instance_destroy(inst);

  	spin_unlock_bh(&log->instances_lock);

  }
  
  static int
  nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
  		  unsigned int range)
  {
  	int status = 0;
  
  	spin_lock_bh(&inst->lock);

  	switch (mode) {
  	case NFULNL_COPY_NONE:
  	case NFULNL_COPY_META:
  		inst->copy_mode = mode;
  		inst->copy_range = 0;
  		break;

  	case NFULNL_COPY_PACKET:
  		inst->copy_mode = mode;

  		if (range == 0)
  			range = NFULNL_COPY_RANGE_MAX;

  		inst->copy_range = min_t(unsigned int,
  					 range, NFULNL_COPY_RANGE_MAX);

  		break;

  	default:
  		status = -EINVAL;
  		break;
  	}
  
  	spin_unlock_bh(&inst->lock);
  
  	return status;
  }
  
  static int
  nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
  {
  	int status;
  
  	spin_lock_bh(&inst->lock);
  	if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
  		status = -ERANGE;
  	else if (nlbufsiz > 131072)
  		status = -ERANGE;
  	else {
  		inst->nlbufsiz = nlbufsiz;
  		status = 0;
  	}
  	spin_unlock_bh(&inst->lock);
  
  	return status;
  }

  static void

  nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
  {
  	spin_lock_bh(&inst->lock);
  	inst->flushtimeout = timeout;
  	spin_unlock_bh(&inst->lock);

  }

  static void

  nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
  {
  	spin_lock_bh(&inst->lock);
  	inst->qthreshold = qthresh;
  	spin_unlock_bh(&inst->lock);

  }

  static int
  nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
  {
  	spin_lock_bh(&inst->lock);

  	inst->flags = flags;

  	spin_unlock_bh(&inst->lock);
  
  	return 0;
  }

  static struct sk_buff *

  nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size,
  		 unsigned int pkt_size)

  {
  	struct sk_buff *skb;

  	unsigned int n;

  	/* alloc skb which should be big enough for a whole multipart
  	 * message.  WARNING: has to be <= 128k due to slab restrictions */

  	n = max(inst_size, pkt_size);

  	skb = alloc_skb(n, GFP_ATOMIC | __GFP_NOWARN);

  	if (!skb) {

  		if (n > pkt_size) {
  			/* try to allocate only as much as we need for current
  			 * packet */

  			skb = alloc_skb(pkt_size, GFP_ATOMIC);

  		}

  	}
  
  	return skb;
  }

  static void

  __nfulnl_send(struct nfulnl_instance *inst)
  {

  	if (inst->qlen > 1) {
  		struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
  						 NLMSG_DONE,
  						 sizeof(struct nfgenmsg),
  						 0);

  		if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d
  ",
  			      inst->skb->len, skb_tailroom(inst->skb))) {
  			kfree_skb(inst->skb);

  			goto out;

  		}

  	}

  	nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid,
  			  MSG_DONTWAIT);
  out:

  	inst->qlen = 0;
  	inst->skb = NULL;

  }

  static void
  __nfulnl_flush(struct nfulnl_instance *inst)
  {
  	/* timer holds a reference */
  	if (del_timer(&inst->timer))
  		instance_put(inst);
  	if (inst->skb)
  		__nfulnl_send(inst);
  }

  static void

  nfulnl_timer(struct timer_list *t)

  {

  	struct nfulnl_instance *inst = from_timer(inst, t, timer);

  	spin_lock_bh(&inst->lock);

  	if (inst->skb)
  		__nfulnl_send(inst);

  	spin_unlock_bh(&inst->lock);

  	instance_put(inst);

  }

  static u32 nfulnl_get_bridge_size(const struct sk_buff *skb)
  {
  	u32 size = 0;
  
  	if (!skb_mac_header_was_set(skb))
  		return 0;
  
  	if (skb_vlan_tag_present(skb)) {
  		size += nla_total_size(0); /* nested */
  		size += nla_total_size(sizeof(u16)); /* id */
  		size += nla_total_size(sizeof(u16)); /* tag */
  	}
  
  	if (skb->network_header > skb->mac_header)
  		size += nla_total_size(skb->network_header - skb->mac_header);
  
  	return size;
  }
  
  static int nfulnl_put_bridge(struct nfulnl_instance *inst, const struct sk_buff *skb)
  {
  	if (!skb_mac_header_was_set(skb))
  		return 0;
  
  	if (skb_vlan_tag_present(skb)) {
  		struct nlattr *nest;
  
  		nest = nla_nest_start(inst->skb, NFULA_VLAN);
  		if (!nest)
  			goto nla_put_failure;
  
  		if (nla_put_be16(inst->skb, NFULA_VLAN_TCI, htons(skb->vlan_tci)) ||
  		    nla_put_be16(inst->skb, NFULA_VLAN_PROTO, skb->vlan_proto))
  			goto nla_put_failure;
  
  		nla_nest_end(inst->skb, nest);
  	}
  
  	if (skb->mac_header < skb->network_header) {
  		int len = (int)(skb->network_header - skb->mac_header);
  
  		if (nla_put(inst->skb, NFULA_L2HDR, len, skb_mac_header(skb)))
  			goto nla_put_failure;
  	}
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }

  /* This is an inline function, we don't really care about a long
   * list of arguments */

  static inline int

  __build_packet_message(struct nfnl_log_net *log,
  			struct nfulnl_instance *inst,

  			const struct sk_buff *skb,

  			unsigned int data_len,

  			u_int8_t pf,

  			unsigned int hooknum,
  			const struct net_device *indev,
  			const struct net_device *outdev,

  			const char *prefix, unsigned int plen,
  			const struct nfnl_ct_hook *nfnl_ct,
  			struct nf_conn *ct, enum ip_conntrack_info ctinfo)

  {

  	struct nfulnl_msg_packet_hdr pmsg;
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;

  	sk_buff_data_t old_tail = inst->skb->tail;

  	struct sock *sk;

  	const unsigned char *hwhdrp;

  	nlh = nlmsg_put(inst->skb, 0, 0,

  			nfnl_msg_type(NFNL_SUBSYS_ULOG, NFULNL_MSG_PACKET),

  			sizeof(struct nfgenmsg), 0);
  	if (!nlh)
  		return -1;
  	nfmsg = nlmsg_data(nlh);

  	nfmsg->nfgen_family = pf;
  	nfmsg->version = NFNETLINK_V0;
  	nfmsg->res_id = htons(inst->group_num);

  	memset(&pmsg, 0, sizeof(pmsg));

  	pmsg.hw_protocol	= skb->protocol;

  	pmsg.hook		= hooknum;

  	if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
  		goto nla_put_failure;

  	if (prefix &&
  	    nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
  		goto nla_put_failure;

  
  	if (indev) {

  #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)

  		if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
  				 htonl(indev->ifindex)))
  			goto nla_put_failure;

  #else
  		if (pf == PF_BRIDGE) {
  			/* Case 1: outdev is physical input device, we need to
  			 * look for bridge group (when called from
  			 * netfilter_bridge) */

  			if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
  					 htonl(indev->ifindex)) ||

  			/* this is the bridge group "brX" */

  			/* rcu_read_lock()ed by nf_hook_thresh or
  			 * nf_log_packet.
  			 */

  			    nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
  					 htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
  				goto nla_put_failure;

  		} else {

  			struct net_device *physindev;

  			/* Case 2: indev is bridge group, we need to look for
  			 * physical device (when called from ipv4) */

  			if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
  					 htonl(indev->ifindex)))
  				goto nla_put_failure;

  
  			physindev = nf_bridge_get_physindev(skb);
  			if (physindev &&

  			    nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,

  					 htonl(physindev->ifindex)))

  				goto nla_put_failure;

  		}
  #endif

  	}
  
  	if (outdev) {

  #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER)

  		if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
  				 htonl(outdev->ifindex)))
  			goto nla_put_failure;

  #else
  		if (pf == PF_BRIDGE) {
  			/* Case 1: outdev is physical output device, we need to
  			 * look for bridge group (when called from
  			 * netfilter_bridge) */

  			if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
  					 htonl(outdev->ifindex)) ||

  			/* this is the bridge group "brX" */

  			/* rcu_read_lock()ed by nf_hook_thresh or
  			 * nf_log_packet.
  			 */

  			    nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
  					 htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
  				goto nla_put_failure;

  		} else {

  			struct net_device *physoutdev;

  			/* Case 2: indev is a bridge group, we need to look
  			 * for physical device (when called from ipv4) */

  			if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
  					 htonl(outdev->ifindex)))
  				goto nla_put_failure;

  
  			physoutdev = nf_bridge_get_physoutdev(skb);
  			if (physoutdev &&

  			    nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,

  					 htonl(physoutdev->ifindex)))

  				goto nla_put_failure;

  		}
  #endif

  	}

  	if (skb->mark &&
  	    nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
  		goto nla_put_failure;

  	if (indev && skb->dev &&
  	    skb->mac_header != skb->network_header) {

  		struct nfulnl_msg_packet_hw phw;

  		int len;
  
  		memset(&phw, 0, sizeof(phw));
  		len = dev_parse_header(skb, phw.hw_addr);

  		if (len > 0) {
  			phw.hw_addrlen = htons(len);

  			if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
  				goto nla_put_failure;

  		}

  	}

  	if (indev && skb_mac_header_was_set(skb)) {

  		if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||

  		    nla_put_be16(inst->skb, NFULA_HWLEN,

  				 htons(skb->dev->hard_header_len)))
  			goto nla_put_failure;
  
  		hwhdrp = skb_mac_header(skb);
  
  		if (skb->dev->type == ARPHRD_SIT)
  			hwhdrp -= ETH_HLEN;
  
  		if (hwhdrp >= skb->head &&
  		    nla_put(inst->skb, NFULA_HWHEADER,
  			    skb->dev->hard_header_len, hwhdrp))

  			goto nla_put_failure;

  	}

  	if (hooknum <= NF_INET_FORWARD && skb->tstamp) {

  		struct nfulnl_msg_packet_timestamp ts;

  		struct timespec64 kts = ktime_to_timespec64(skb->tstamp);
  		ts.sec = cpu_to_be64(kts.tv_sec);
  		ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC);

  		if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
  			goto nla_put_failure;

  	}
  
  	/* UID */

  	sk = skb->sk;

  	if (sk && sk_fullsock(sk)) {

  		read_lock_bh(&sk->sk_callback_lock);
  		if (sk->sk_socket && sk->sk_socket->file) {
  			struct file *file = sk->sk_socket->file;

  			const struct cred *cred = file->f_cred;
  			struct user_namespace *user_ns = inst->peer_user_ns;
  			__be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
  			__be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));

  			read_unlock_bh(&sk->sk_callback_lock);

  			if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
  			    nla_put_be32(inst->skb, NFULA_GID, gid))
  				goto nla_put_failure;

  		} else

  			read_unlock_bh(&sk->sk_callback_lock);

  	}

  	/* local sequence number */

  	if ((inst->flags & NFULNL_CFG_F_SEQ) &&
  	    nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
  		goto nla_put_failure;

  	/* global sequence number */

  	if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
  	    nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,

  			 htonl(atomic_inc_return(&log->global_seq))))

  		goto nla_put_failure;

  	if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
  				 NFULA_CT, NFULA_CT_INFO) < 0)
  		goto nla_put_failure;

  	if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
  	    nfulnl_put_bridge(inst, skb) < 0)
  		goto nla_put_failure;

  	if (data_len) {

  		struct nlattr *nla;
  		int size = nla_attr_size(data_len);

  		if (skb_tailroom(inst->skb) < nla_total_size(data_len))
  			goto nla_put_failure;

  		nla = skb_put(inst->skb, nla_total_size(data_len));

  		nla->nla_type = NFULA_PAYLOAD;
  		nla->nla_len = size;

  		if (skb_copy_bits(skb, 0, nla_data(nla), data_len))

  			BUG();
  	}

  	nlh->nlmsg_len = inst->skb->tail - old_tail;
  	return 0;

  nla_put_failure:

  	PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg
  ");
  	return -1;
  }

  static const struct nf_loginfo default_loginfo = {

  	.type =		NF_LOG_TYPE_ULOG,
  	.u = {
  		.ulog = {
  			.copy_len	= 0xffff,
  			.group		= 0,
  			.qthreshold	= 1,
  		},
  	},
  };
  
  /* log handler for internal netfilter logging api */

  static void

  nfulnl_log_packet(struct net *net,
  		  u_int8_t pf,

  		  unsigned int hooknum,
  		  const struct sk_buff *skb,
  		  const struct net_device *in,
  		  const struct net_device *out,
  		  const struct nf_loginfo *li_user,
  		  const char *prefix)
  {

  	size_t size;
  	unsigned int data_len;

  	struct nfulnl_instance *inst;
  	const struct nf_loginfo *li;
  	unsigned int qthreshold;

  	unsigned int plen = 0;

  	struct nfnl_log_net *log = nfnl_log_pernet(net);

  	const struct nfnl_ct_hook *nfnl_ct = NULL;
  	struct nf_conn *ct = NULL;
  	enum ip_conntrack_info uninitialized_var(ctinfo);

  	if (li_user && li_user->type == NF_LOG_TYPE_ULOG)

  		li = li_user;
  	else
  		li = &default_loginfo;

  	inst = instance_lookup_get(log, li->u.ulog.group);

  	if (!inst)

  		return;

  	if (prefix)

  		plen = strlen(prefix) + 1;

  	/* FIXME: do we want to make the size calculation conditional based on
  	 * what is actually present?  way more branches and checks, but more
  	 * memory efficient... */

  	size = nlmsg_total_size(sizeof(struct nfgenmsg))

  		+ nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
  		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
  		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */

  #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)

  		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
  		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */

  #endif

  		+ nla_total_size(sizeof(u_int32_t))	/* mark */
  		+ nla_total_size(sizeof(u_int32_t))	/* uid */

  		+ nla_total_size(sizeof(u_int32_t))	/* gid */

  		+ nla_total_size(plen)			/* prefix */
  		+ nla_total_size(sizeof(struct nfulnl_msg_packet_hw))

  		+ nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp))
  		+ nla_total_size(sizeof(struct nfgenmsg));	/* NLMSG_DONE */

  	if (in && skb_mac_header_was_set(skb)) {

  		size += nla_total_size(skb->dev->hard_header_len)

  			+ nla_total_size(sizeof(u_int16_t))	/* hwtype */
  			+ nla_total_size(sizeof(u_int16_t));	/* hwlen */
  	}

  	spin_lock_bh(&inst->lock);

  	if (inst->flags & NFULNL_CFG_F_SEQ)

  		size += nla_total_size(sizeof(u_int32_t));

  	if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)

  		size += nla_total_size(sizeof(u_int32_t));

  	if (inst->flags & NFULNL_CFG_F_CONNTRACK) {
  		nfnl_ct = rcu_dereference(nfnl_ct_hook);
  		if (nfnl_ct != NULL) {
  			ct = nfnl_ct->get_ct(skb, &ctinfo);
  			if (ct != NULL)
  				size += nfnl_ct->build_size(ct);
  		}
  	}

  	if (pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE)
  		size += nfulnl_get_bridge_size(skb);

  	qthreshold = inst->qthreshold;
  	/* per-rule qthreshold overrides per-instance */

  	if (li->u.ulog.qthreshold)
  		if (qthreshold > li->u.ulog.qthreshold)
  			qthreshold = li->u.ulog.qthreshold;

  	switch (inst->copy_mode) {
  	case NFULNL_COPY_META:
  	case NFULNL_COPY_NONE:
  		data_len = 0;
  		break;

  	case NFULNL_COPY_PACKET:

  		data_len = inst->copy_range;
  		if ((li->u.ulog.flags & NF_LOG_F_COPY_LEN) &&
  		    (li->u.ulog.copy_len < data_len))
  			data_len = li->u.ulog.copy_len;
  
  		if (data_len > skb->len)

  			data_len = skb->len;

  		size += nla_total_size(data_len);

  		break;

  	case NFULNL_COPY_DISABLED:

  	default:

  		goto unlock_and_release;

  	}

  	if (inst->skb && size > skb_tailroom(inst->skb)) {

  		/* either the queue len is too high or we don't have
  		 * enough room in the skb left. flush to userspace. */

  		__nfulnl_flush(inst);

  	}

  	if (!inst->skb) {

  		inst->skb = nfulnl_alloc_skb(net, inst->peer_portid,
  					     inst->nlbufsiz, size);

  		if (!inst->skb)

  			goto alloc_failure;

  	}

  	inst->qlen++;

  	__build_packet_message(log, inst, skb, data_len, pf,

  				hooknum, in, out, prefix, plen,
  				nfnl_ct, ct, ctinfo);

  	if (inst->qlen >= qthreshold)
  		__nfulnl_flush(inst);

  	/* timer_pending always called within inst->lock, so there
  	 * is no chance of a race here */

  	else if (!timer_pending(&inst->timer)) {

  		instance_get(inst);
  		inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
  		add_timer(&inst->timer);
  	}

  unlock_and_release:
  	spin_unlock_bh(&inst->lock);
  	instance_put(inst);

  	return;
  
  alloc_failure:

  	/* FIXME: statistics */

  	goto unlock_and_release;

  }
  
  static int
  nfulnl_rcv_nl_event(struct notifier_block *this,
  		   unsigned long event, void *ptr)
  {
  	struct netlink_notify *n = ptr;

  	struct nfnl_log_net *log = nfnl_log_pernet(n->net);

  	if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {

  		int i;

  		/* destroy all instances for this portid */

  		spin_lock_bh(&log->instances_lock);

  		for  (i = 0; i < INSTANCE_BUCKETS; i++) {

  			struct hlist_node *t2;

  			struct nfulnl_instance *inst;

  			struct hlist_head *head = &log->instance_table[i];

  			hlist_for_each_entry_safe(inst, t2, head, hlist) {

  				if (n->portid == inst->peer_portid)

  					__instance_destroy(inst);
  			}
  		}

  		spin_unlock_bh(&log->instances_lock);

  	}
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block nfulnl_rtnl_notifier = {
  	.notifier_call	= nfulnl_rcv_nl_event,
  };

  static int nfulnl_recv_unsupp(struct net *net, struct sock *ctnl,
  			      struct sk_buff *skb, const struct nlmsghdr *nlh,

  			      const struct nlattr * const nfqa[],
  			      struct netlink_ext_ack *extack)

  {
  	return -ENOTSUPP;
  }

  static struct nf_logger nfulnl_logger __read_mostly = {

  	.name	= "nfnetlink_log",

  	.type	= NF_LOG_TYPE_ULOG,

  	.logfn	= nfulnl_log_packet,

  	.me	= THIS_MODULE,
  };

  static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
  	[NFULA_CFG_CMD]		= { .len = sizeof(struct nfulnl_msg_config_cmd) },
  	[NFULA_CFG_MODE]	= { .len = sizeof(struct nfulnl_msg_config_mode) },
  	[NFULA_CFG_TIMEOUT]	= { .type = NLA_U32 },
  	[NFULA_CFG_QTHRESH]	= { .type = NLA_U32 },
  	[NFULA_CFG_NLBUFSIZ]	= { .type = NLA_U32 },
  	[NFULA_CFG_FLAGS]	= { .type = NLA_U16 },

  };

  static int nfulnl_recv_config(struct net *net, struct sock *ctnl,
  			      struct sk_buff *skb, const struct nlmsghdr *nlh,

  			      const struct nlattr * const nfula[],
  			      struct netlink_ext_ack *extack)

  {

  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);

  	u_int16_t group_num = ntohs(nfmsg->res_id);
  	struct nfulnl_instance *inst;

  	struct nfulnl_msg_config_cmd *cmd = NULL;

  	struct nfnl_log_net *log = nfnl_log_pernet(net);

  	int ret = 0;

  	u16 flags = 0;

  	if (nfula[NFULA_CFG_CMD]) {
  		u_int8_t pf = nfmsg->nfgen_family;
  		cmd = nla_data(nfula[NFULA_CFG_CMD]);
  
  		/* Commands without queue context */
  		switch (cmd->command) {
  		case NFULNL_CFG_CMD_PF_BIND:

  			return nf_log_bind_pf(net, pf, &nfulnl_logger);

  		case NFULNL_CFG_CMD_PF_UNBIND:

  			nf_log_unbind_pf(net, pf);

  			return 0;
  		}
  	}

  	inst = instance_lookup_get(log, group_num);

  	if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {

  		ret = -EPERM;
  		goto out_put;
  	}

  	/* Check if we support these flags in first place, dependencies should
  	 * be there too not to break atomicity.
  	 */
  	if (nfula[NFULA_CFG_FLAGS]) {
  		flags = ntohs(nla_get_be16(nfula[NFULA_CFG_FLAGS]));
  
  		if ((flags & NFULNL_CFG_F_CONNTRACK) &&
  		    !rcu_access_pointer(nfnl_ct_hook)) {
  #ifdef CONFIG_MODULES
  			nfnl_unlock(NFNL_SUBSYS_ULOG);
  			request_module("ip_conntrack_netlink");
  			nfnl_lock(NFNL_SUBSYS_ULOG);
  			if (rcu_access_pointer(nfnl_ct_hook)) {
  				ret = -EAGAIN;
  				goto out_put;
  			}
  #endif
  			ret = -EOPNOTSUPP;
  			goto out_put;
  		}
  	}

  	if (cmd != NULL) {

  		switch (cmd->command) {
  		case NFULNL_CFG_CMD_BIND:
  			if (inst) {
  				ret = -EBUSY;
  				goto out_put;
  			}

  			inst = instance_create(net, group_num,

  					       NETLINK_CB(skb).portid,

  					       sk_user_ns(NETLINK_CB(skb).sk));

  			if (IS_ERR(inst)) {
  				ret = PTR_ERR(inst);

  				goto out;

  			}
  			break;
  		case NFULNL_CFG_CMD_UNBIND:
  			if (!inst) {
  				ret = -ENODEV;

  				goto out;

  			}

  			instance_destroy(log, inst);

  			goto out_put;

  		default:

  			ret = -ENOTSUPP;

  			goto out_put;

  		}

  	} else if (!inst) {
  		ret = -ENODEV;
  		goto out;

  	}

  	if (nfula[NFULA_CFG_MODE]) {

  		struct nfulnl_msg_config_mode *params =
  			nla_data(nfula[NFULA_CFG_MODE]);

  
  		nfulnl_set_mode(inst, params->copy_mode,

  				ntohl(params->copy_range));

  	}

  	if (nfula[NFULA_CFG_TIMEOUT]) {

  		__be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);

  
  		nfulnl_set_timeout(inst, ntohl(timeout));
  	}

  	if (nfula[NFULA_CFG_NLBUFSIZ]) {

  		__be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);

  
  		nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
  	}

  	if (nfula[NFULA_CFG_QTHRESH]) {

  		__be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);

  
  		nfulnl_set_qthresh(inst, ntohl(qthresh));
  	}

  	if (nfula[NFULA_CFG_FLAGS])

  		nfulnl_set_flags(inst, flags);

  out_put:
  	instance_put(inst);

  out:

  	return ret;
  }

  static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {

  	[NFULNL_MSG_PACKET]	= { .call = nfulnl_recv_unsupp,

  				    .attr_count = NFULA_MAX, },

  	[NFULNL_MSG_CONFIG]	= { .call = nfulnl_recv_config,

  				    .attr_count = NFULA_CFG_MAX,
  				    .policy = nfula_cfg_policy },

  };

  static const struct nfnetlink_subsystem nfulnl_subsys = {

  	.name		= "log",
  	.subsys_id	= NFNL_SUBSYS_ULOG,
  	.cb_count	= NFULNL_MSG_MAX,

  	.cb		= nfulnl_cb,
  };
  
  #ifdef CONFIG_PROC_FS
  struct iter_state {

  	struct seq_net_private p;

  	unsigned int bucket;
  };

  static struct hlist_node *get_first(struct net *net, struct iter_state *st)

  {

  	struct nfnl_log_net *log;

  	if (!st)
  		return NULL;

  	log = nfnl_log_pernet(net);

  	for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {

  		struct hlist_head *head = &log->instance_table[st->bucket];
  
  		if (!hlist_empty(head))
  			return rcu_dereference_bh(hlist_first_rcu(head));

  	}
  	return NULL;
  }

  static struct hlist_node *get_next(struct net *net, struct iter_state *st,
  				   struct hlist_node *h)

  {

  	h = rcu_dereference_bh(hlist_next_rcu(h));

  	while (!h) {

  		struct nfnl_log_net *log;
  		struct hlist_head *head;

  		if (++st->bucket >= INSTANCE_BUCKETS)
  			return NULL;

  		log = nfnl_log_pernet(net);
  		head = &log->instance_table[st->bucket];
  		h = rcu_dereference_bh(hlist_first_rcu(head));

  	}
  	return h;
  }

  static struct hlist_node *get_idx(struct net *net, struct iter_state *st,
  				  loff_t pos)

  {
  	struct hlist_node *head;

  	head = get_first(net, st);

  
  	if (head)

  		while (pos && (head = get_next(net, st, head)))

  			pos--;
  	return pos ? NULL : head;
  }

  static void *seq_start(struct seq_file *s, loff_t *pos)

  	__acquires(rcu_bh)

  {

  	rcu_read_lock_bh();

  	return get_idx(seq_file_net(s), s->private, *pos);

  }
  
  static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
  {
  	(*pos)++;

  	return get_next(seq_file_net(s), s->private, v);

  }
  
  static void seq_stop(struct seq_file *s, void *v)

  	__releases(rcu_bh)

  {

  	rcu_read_unlock_bh();

  }
  
  static int seq_show(struct seq_file *s, void *v)
  {
  	const struct nfulnl_instance *inst = v;

  	seq_printf(s, "%5u %6u %5u %1u %5u %6u %2u
  ",

  		   inst->group_num,
  		   inst->peer_portid, inst->qlen,
  		   inst->copy_mode, inst->copy_range,

  		   inst->flushtimeout, refcount_read(&inst->use));

  
  	return 0;

  }

  static const struct seq_operations nful_seq_ops = {

  	.start	= seq_start,
  	.next	= seq_next,
  	.stop	= seq_stop,
  	.show	= seq_show,
  };

  #endif /* PROC_FS */

  static int __net_init nfnl_log_net_init(struct net *net)

  {

  	unsigned int i;
  	struct nfnl_log_net *log = nfnl_log_pernet(net);

  #ifdef CONFIG_PROC_FS
  	struct proc_dir_entry *proc;
  	kuid_t root_uid;
  	kgid_t root_gid;
  #endif

  	for (i = 0; i < INSTANCE_BUCKETS; i++)

  		INIT_HLIST_HEAD(&log->instance_table[i]);
  	spin_lock_init(&log->instances_lock);
  
  #ifdef CONFIG_PROC_FS

  	proc = proc_create_net("nfnetlink_log", 0440, net->nf.proc_netfilter,
  			&nful_seq_ops, sizeof(struct iter_state));

  	if (!proc)

  		return -ENOMEM;

  
  	root_uid = make_kuid(net->user_ns, 0);
  	root_gid = make_kgid(net->user_ns, 0);
  	if (uid_valid(root_uid) && gid_valid(root_gid))
  		proc_set_user(proc, root_uid, root_gid);

  #endif
  	return 0;
  }
  
  static void __net_exit nfnl_log_net_exit(struct net *net)
  {

  	struct nfnl_log_net *log = nfnl_log_pernet(net);
  	unsigned int i;

  #ifdef CONFIG_PROC_FS

  	remove_proc_entry("nfnetlink_log", net->nf.proc_netfilter);

  #endif

  	nf_log_unset(net, &nfulnl_logger);

  	for (i = 0; i < INSTANCE_BUCKETS; i++)
  		WARN_ON_ONCE(!hlist_empty(&log->instance_table[i]));

  }
  
  static struct pernet_operations nfnl_log_net_ops = {
  	.init	= nfnl_log_net_init,
  	.exit	= nfnl_log_net_exit,
  	.id	= &nfnl_log_net_id,
  	.size	= sizeof(struct nfnl_log_net),
  };
  
  static int __init nfnetlink_log_init(void)
  {

  	int status;
  
  	status = register_pernet_subsys(&nfnl_log_net_ops);
  	if (status < 0) {
  		pr_err("failed to register pernet ops
  ");
  		goto out;
  	}

  	netlink_register_notifier(&nfulnl_rtnl_notifier);
  	status = nfnetlink_subsys_register(&nfulnl_subsys);
  	if (status < 0) {

  		pr_err("failed to create netlink socket
  ");

  		goto cleanup_netlink_notifier;
  	}

  	status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
  	if (status < 0) {

  		pr_err("failed to register logger
  ");

  		goto cleanup_subsys;
  	}

  	return status;

  cleanup_subsys:

  	nfnetlink_subsys_unregister(&nfulnl_subsys);
  cleanup_netlink_notifier:
  	netlink_unregister_notifier(&nfulnl_rtnl_notifier);

  	unregister_pernet_subsys(&nfnl_log_net_ops);
  out:

  	return status;
  }

  static void __exit nfnetlink_log_fini(void)

  {

  	nfnetlink_subsys_unregister(&nfulnl_subsys);
  	netlink_unregister_notifier(&nfulnl_rtnl_notifier);

  	unregister_pernet_subsys(&nfnl_log_net_ops);

  	nf_log_unregister(&nfulnl_logger);

  }
  
  MODULE_DESCRIPTION("netfilter userspace logging");
  MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);

  MODULE_ALIAS_NF_LOGGER(AF_INET, 1);
  MODULE_ALIAS_NF_LOGGER(AF_INET6, 1);
  MODULE_ALIAS_NF_LOGGER(AF_BRIDGE, 1);

  MODULE_ALIAS_NF_LOGGER(3, 1); /* NFPROTO_ARP */

  MODULE_ALIAS_NF_LOGGER(5, 1); /* NFPROTO_NETDEV */

  module_init(nfnetlink_log_init);
  module_exit(nfnetlink_log_fini);