text: /* Connection tracking via netlink socket. Allows for user space
   * protocol helpers and general trouble making from userspace.
   *
   * (C) 2001 by Jay Schulist <jschlst@samba.org>
   * (C) 2002-2006 by Harald Welte <laforge@gnumonks.org>
   * (C) 2003 by Patrick Mchardy <kaber@trash.net>
   * (C) 2005-2012 by Pablo Neira Ayuso <pablo@netfilter.org>
   *
   * Initial connection tracking via netlink development funded and
   * generally made possible by Network Robots, Inc. (www.networkrobots.com)
   *
   * Further development of this code funded by Astaro AG (http://www.astaro.com)
   *
   * This software may be used and distributed according to the terms
   * of the GNU General Public License, incorporated herein by reference.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/rculist.h>
  #include <linux/rculist_nulls.h>
  #include <linux/types.h>
  #include <linux/timer.h>
  #include <linux/security.h>
  #include <linux/skbuff.h>
  #include <linux/errno.h>
  #include <linux/netlink.h>
  #include <linux/spinlock.h>
  #include <linux/interrupt.h>
  #include <linux/slab.h>
  
  #include <linux/netfilter.h>
  #include <net/netlink.h>
  #include <net/sock.h>
  #include <net/netfilter/nf_conntrack.h>
  #include <net/netfilter/nf_conntrack_core.h>
  #include <net/netfilter/nf_conntrack_expect.h>
  #include <net/netfilter/nf_conntrack_helper.h>
  #include <net/netfilter/nf_conntrack_seqadj.h>
  #include <net/netfilter/nf_conntrack_l3proto.h>
  #include <net/netfilter/nf_conntrack_l4proto.h>
  #include <net/netfilter/nf_conntrack_tuple.h>
  #include <net/netfilter/nf_conntrack_acct.h>
  #include <net/netfilter/nf_conntrack_zones.h>
  #include <net/netfilter/nf_conntrack_timestamp.h>
  #include <net/netfilter/nf_conntrack_labels.h>
  #ifdef CONFIG_NF_NAT_NEEDED
  #include <net/netfilter/nf_nat_core.h>
  #include <net/netfilter/nf_nat_l4proto.h>
  #include <net/netfilter/nf_nat_helper.h>
  #endif
  
  #include <linux/netfilter/nfnetlink.h>
  #include <linux/netfilter/nfnetlink_conntrack.h>
  
  MODULE_LICENSE("GPL");
  
  static char __initdata version[] = "0.93";
  
  static inline int
  ctnetlink_dump_tuples_proto(struct sk_buff *skb,
  			    const struct nf_conntrack_tuple *tuple,
  			    struct nf_conntrack_l4proto *l4proto)
  {
  	int ret = 0;
  	struct nlattr *nest_parms;
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_PROTO | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (nla_put_u8(skb, CTA_PROTO_NUM, tuple->dst.protonum))
  		goto nla_put_failure;
  
  	if (likely(l4proto->tuple_to_nlattr))
  		ret = l4proto->tuple_to_nlattr(skb, tuple);
  
  	nla_nest_end(skb, nest_parms);
  
  	return ret;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_tuples_ip(struct sk_buff *skb,
  			 const struct nf_conntrack_tuple *tuple,
  			 struct nf_conntrack_l3proto *l3proto)
  {
  	int ret = 0;
  	struct nlattr *nest_parms;
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_IP | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  
  	if (likely(l3proto->tuple_to_nlattr))
  		ret = l3proto->tuple_to_nlattr(skb, tuple);
  
  	nla_nest_end(skb, nest_parms);
  
  	return ret;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  ctnetlink_dump_tuples(struct sk_buff *skb,
  		      const struct nf_conntrack_tuple *tuple)
  {
  	int ret;
  	struct nf_conntrack_l3proto *l3proto;
  	struct nf_conntrack_l4proto *l4proto;
  
  	rcu_read_lock();
  	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);
  	ret = ctnetlink_dump_tuples_ip(skb, tuple, l3proto);
  
  	if (ret >= 0) {
  		l4proto = __nf_ct_l4proto_find(tuple->src.l3num,
  					       tuple->dst.protonum);
  		ret = ctnetlink_dump_tuples_proto(skb, tuple, l4proto);
  	}
  	rcu_read_unlock();
  	return ret;
  }
  
  static inline int
  ctnetlink_dump_zone_id(struct sk_buff *skb, int attrtype,
  		       const struct nf_conntrack_zone *zone, int dir)
  {
  	if (zone->id == NF_CT_DEFAULT_ZONE_ID || zone->dir != dir)
  		return 0;
  	if (nla_put_be16(skb, attrtype, htons(zone->id)))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_status(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	if (nla_put_be32(skb, CTA_STATUS, htonl(ct->status)))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_timeout(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	long timeout = ((long)ct->timeout.expires - (long)jiffies) / HZ;
  
  	if (timeout < 0)
  		timeout = 0;
  
  	if (nla_put_be32(skb, CTA_TIMEOUT, htonl(timeout)))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_protoinfo(struct sk_buff *skb, struct nf_conn *ct)
  {
  	struct nf_conntrack_l4proto *l4proto;
  	struct nlattr *nest_proto;
  	int ret;
  
  	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
  	if (!l4proto->to_nlattr)
  		return 0;
  
  	nest_proto = nla_nest_start(skb, CTA_PROTOINFO | NLA_F_NESTED);
  	if (!nest_proto)
  		goto nla_put_failure;
  
  	ret = l4proto->to_nlattr(skb, nest_proto, ct);
  
  	nla_nest_end(skb, nest_proto);
  
  	return ret;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_helpinfo(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nlattr *nest_helper;
  	const struct nf_conn_help *help = nfct_help(ct);
  	struct nf_conntrack_helper *helper;
  
  	if (!help)
  		return 0;
  
  	helper = rcu_dereference(help->helper);
  	if (!helper)
  		goto out;
  
  	nest_helper = nla_nest_start(skb, CTA_HELP | NLA_F_NESTED);
  	if (!nest_helper)
  		goto nla_put_failure;
  	if (nla_put_string(skb, CTA_HELP_NAME, helper->name))
  		goto nla_put_failure;
  
  	if (helper->to_nlattr)
  		helper->to_nlattr(skb, ct);
  
  	nla_nest_end(skb, nest_helper);
  out:
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  dump_counters(struct sk_buff *skb, struct nf_conn_acct *acct,
  	      enum ip_conntrack_dir dir, int type)
  {
  	enum ctattr_type attr = dir ? CTA_COUNTERS_REPLY: CTA_COUNTERS_ORIG;
  	struct nf_conn_counter *counter = acct->counter;
  	struct nlattr *nest_count;
  	u64 pkts, bytes;
  
  	if (type == IPCTNL_MSG_CT_GET_CTRZERO) {
  		pkts = atomic64_xchg(&counter[dir].packets, 0);
  		bytes = atomic64_xchg(&counter[dir].bytes, 0);
  	} else {
  		pkts = atomic64_read(&counter[dir].packets);
  		bytes = atomic64_read(&counter[dir].bytes);
  	}
  
  	nest_count = nla_nest_start(skb, attr | NLA_F_NESTED);
  	if (!nest_count)
  		goto nla_put_failure;
  
  	if (nla_put_be64(skb, CTA_COUNTERS_PACKETS, cpu_to_be64(pkts)) ||
  	    nla_put_be64(skb, CTA_COUNTERS_BYTES, cpu_to_be64(bytes)))
  		goto nla_put_failure;
  
  	nla_nest_end(skb, nest_count);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  ctnetlink_dump_acct(struct sk_buff *skb, const struct nf_conn *ct, int type)
  {
  	struct nf_conn_acct *acct = nf_conn_acct_find(ct);
  
  	if (!acct)
  		return 0;
  
  	if (dump_counters(skb, acct, IP_CT_DIR_ORIGINAL, type) < 0)
  		return -1;
  	if (dump_counters(skb, acct, IP_CT_DIR_REPLY, type) < 0)
  		return -1;
  
  	return 0;
  }
  
  static int
  ctnetlink_dump_timestamp(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nlattr *nest_count;
  	const struct nf_conn_tstamp *tstamp;
  
  	tstamp = nf_conn_tstamp_find(ct);
  	if (!tstamp)
  		return 0;
  
  	nest_count = nla_nest_start(skb, CTA_TIMESTAMP | NLA_F_NESTED);
  	if (!nest_count)
  		goto nla_put_failure;
  
  	if (nla_put_be64(skb, CTA_TIMESTAMP_START, cpu_to_be64(tstamp->start)) ||
  	    (tstamp->stop != 0 && nla_put_be64(skb, CTA_TIMESTAMP_STOP,
  					       cpu_to_be64(tstamp->stop))))
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_count);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  #ifdef CONFIG_NF_CONNTRACK_MARK
  static inline int
  ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	if (nla_put_be32(skb, CTA_MARK, htonl(ct->mark)))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  #else
  #define ctnetlink_dump_mark(a, b) (0)
  #endif
  
  #ifdef CONFIG_NF_CONNTRACK_SECMARK
  static inline int
  ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nlattr *nest_secctx;
  	int len, ret;
  	char *secctx;
  
  	ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
  	if (ret)
  		return 0;
  
  	ret = -1;
  	nest_secctx = nla_nest_start(skb, CTA_SECCTX | NLA_F_NESTED);
  	if (!nest_secctx)
  		goto nla_put_failure;
  
  	if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_secctx);
  
  	ret = 0;
  nla_put_failure:
  	security_release_secctx(secctx, len);
  	return ret;
  }
  #else
  #define ctnetlink_dump_secctx(a, b) (0)
  #endif
  
  #ifdef CONFIG_NF_CONNTRACK_LABELS
  static int ctnetlink_label_size(const struct nf_conn *ct)
  {
  	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
  
  	if (!labels)
  		return 0;
  	return nla_total_size(labels->words * sizeof(long));
  }
  
  static int
  ctnetlink_dump_labels(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
  	unsigned int len, i;
  
  	if (!labels)
  		return 0;
  
  	len = labels->words * sizeof(long);
  	i = 0;
  	do {
  		if (labels->bits[i] != 0)
  			return nla_put(skb, CTA_LABELS, len, labels->bits);
  		i++;
  	} while (i < labels->words);
  
  	return 0;
  }
  #else
  #define ctnetlink_dump_labels(a, b) (0)
  #define ctnetlink_label_size(a)	(0)
  #endif
  
  #define master_tuple(ct) &(ct->master->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
  
  static inline int
  ctnetlink_dump_master(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nlattr *nest_parms;
  
  	if (!(ct->status & IPS_EXPECTED))
  		return 0;
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_MASTER | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, master_tuple(ct)) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  dump_ct_seq_adj(struct sk_buff *skb, const struct nf_ct_seqadj *seq, int type)
  {
  	struct nlattr *nest_parms;
  
  	nest_parms = nla_nest_start(skb, type | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  
  	if (nla_put_be32(skb, CTA_SEQADJ_CORRECTION_POS,
  			 htonl(seq->correction_pos)) ||
  	    nla_put_be32(skb, CTA_SEQADJ_OFFSET_BEFORE,
  			 htonl(seq->offset_before)) ||
  	    nla_put_be32(skb, CTA_SEQADJ_OFFSET_AFTER,
  			 htonl(seq->offset_after)))
  		goto nla_put_failure;
  
  	nla_nest_end(skb, nest_parms);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_ct_seq_adj(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
  	struct nf_ct_seqadj *seq;
  
  	if (!(ct->status & IPS_SEQ_ADJUST) || !seqadj)
  		return 0;
  
  	seq = &seqadj->seq[IP_CT_DIR_ORIGINAL];
  	if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_ORIG) == -1)
  		return -1;
  
  	seq = &seqadj->seq[IP_CT_DIR_REPLY];
  	if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_REPLY) == -1)
  		return -1;
  
  	return 0;
  }
  
  static inline int
  ctnetlink_dump_id(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	if (nla_put_be32(skb, CTA_ID, htonl((unsigned long)ct)))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_dump_use(struct sk_buff *skb, const struct nf_conn *ct)
  {
  	if (nla_put_be32(skb, CTA_USE, htonl(atomic_read(&ct->ct_general.use))))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  ctnetlink_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
  		    struct nf_conn *ct)
  {
  	const struct nf_conntrack_zone *zone;
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	struct nlattr *nest_parms;
  	unsigned int flags = portid ? NLM_F_MULTI : 0, event;
  
  	event = (NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_CT_NEW);
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = nf_ct_l3num(ct);
  	nfmsg->version      = NFNETLINK_V0;
  	nfmsg->res_id	    = 0;
  
  	zone = nf_ct_zone(ct);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_ORIGINAL)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_ORIG) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_REPLY | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_REPLY)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_REPL) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	if (ctnetlink_dump_zone_id(skb, CTA_ZONE, zone,
  				   NF_CT_DEFAULT_ZONE_DIR) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_status(skb, ct) < 0 ||
  	    ctnetlink_dump_timeout(skb, ct) < 0 ||
  	    ctnetlink_dump_acct(skb, ct, type) < 0 ||
  	    ctnetlink_dump_timestamp(skb, ct) < 0 ||
  	    ctnetlink_dump_protoinfo(skb, ct) < 0 ||
  	    ctnetlink_dump_helpinfo(skb, ct) < 0 ||
  	    ctnetlink_dump_mark(skb, ct) < 0 ||
  	    ctnetlink_dump_secctx(skb, ct) < 0 ||
  	    ctnetlink_dump_labels(skb, ct) < 0 ||
  	    ctnetlink_dump_id(skb, ct) < 0 ||
  	    ctnetlink_dump_use(skb, ct) < 0 ||
  	    ctnetlink_dump_master(skb, ct) < 0 ||
  	    ctnetlink_dump_ct_seq_adj(skb, ct) < 0)
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return skb->len;
  
  nlmsg_failure:
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -1;
  }
  
  static inline size_t
  ctnetlink_proto_size(const struct nf_conn *ct)
  {
  	struct nf_conntrack_l3proto *l3proto;
  	struct nf_conntrack_l4proto *l4proto;
  	size_t len = 0;
  
  	rcu_read_lock();
  	l3proto = __nf_ct_l3proto_find(nf_ct_l3num(ct));
  	len += l3proto->nla_size;
  
  	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
  	len += l4proto->nla_size;
  	rcu_read_unlock();
  
  	return len;
  }
  
  static inline size_t
  ctnetlink_acct_size(const struct nf_conn *ct)
  {
  	if (!nf_ct_ext_exist(ct, NF_CT_EXT_ACCT))
  		return 0;
  	return 2 * nla_total_size(0) /* CTA_COUNTERS_ORIG|REPL */
  	       + 2 * nla_total_size(sizeof(uint64_t)) /* CTA_COUNTERS_PACKETS */
  	       + 2 * nla_total_size(sizeof(uint64_t)) /* CTA_COUNTERS_BYTES */
  	       ;
  }
  
  static inline int
  ctnetlink_secctx_size(const struct nf_conn *ct)
  {
  #ifdef CONFIG_NF_CONNTRACK_SECMARK
  	int len, ret;
  
  	ret = security_secid_to_secctx(ct->secmark, NULL, &len);
  	if (ret)
  		return 0;
  
  	return nla_total_size(0) /* CTA_SECCTX */
  	       + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
  #else
  	return 0;
  #endif
  }
  
  static inline size_t
  ctnetlink_timestamp_size(const struct nf_conn *ct)
  {
  #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
  	if (!nf_ct_ext_exist(ct, NF_CT_EXT_TSTAMP))
  		return 0;
  	return nla_total_size(0) + 2 * nla_total_size(sizeof(uint64_t));
  #else
  	return 0;
  #endif
  }
  
  static inline size_t
  ctnetlink_nlmsg_size(const struct nf_conn *ct)
  {
  	return NLMSG_ALIGN(sizeof(struct nfgenmsg))
  	       + 3 * nla_total_size(0) /* CTA_TUPLE_ORIG|REPL|MASTER */
  	       + 3 * nla_total_size(0) /* CTA_TUPLE_IP */
  	       + 3 * nla_total_size(0) /* CTA_TUPLE_PROTO */
  	       + 3 * nla_total_size(sizeof(u_int8_t)) /* CTA_PROTO_NUM */
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_ID */
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_STATUS */
  	       + ctnetlink_acct_size(ct)
  	       + ctnetlink_timestamp_size(ct)
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_TIMEOUT */
  	       + nla_total_size(0) /* CTA_PROTOINFO */
  	       + nla_total_size(0) /* CTA_HELP */
  	       + nla_total_size(NF_CT_HELPER_NAME_LEN) /* CTA_HELP_NAME */
  	       + ctnetlink_secctx_size(ct)
  #ifdef CONFIG_NF_NAT_NEEDED
  	       + 2 * nla_total_size(0) /* CTA_NAT_SEQ_ADJ_ORIG|REPL */
  	       + 6 * nla_total_size(sizeof(u_int32_t)) /* CTA_NAT_SEQ_OFFSET */
  #endif
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_MARK */
  #endif
  #ifdef CONFIG_NF_CONNTRACK_ZONES
  	       + nla_total_size(sizeof(u_int16_t)) /* CTA_ZONE|CTA_TUPLE_ZONE */
  #endif
  	       + ctnetlink_proto_size(ct)
  	       + ctnetlink_label_size(ct)
  	       ;
  }
  
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  static int
  ctnetlink_conntrack_event(unsigned int events, struct nf_ct_event *item)
  {
  	const struct nf_conntrack_zone *zone;
  	struct net *net;
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	struct nlattr *nest_parms;
  	struct nf_conn *ct = item->ct;
  	struct sk_buff *skb;
  	unsigned int type;
  	unsigned int flags = 0, group;
  	int err;
  
  	/* ignore our fake conntrack entry */
  	if (nf_ct_is_untracked(ct))
  		return 0;
  
  	if (events & (1 << IPCT_DESTROY)) {
  		type = IPCTNL_MSG_CT_DELETE;
  		group = NFNLGRP_CONNTRACK_DESTROY;
  	} else  if (events & ((1 << IPCT_NEW) | (1 << IPCT_RELATED))) {
  		type = IPCTNL_MSG_CT_NEW;
  		flags = NLM_F_CREATE|NLM_F_EXCL;
  		group = NFNLGRP_CONNTRACK_NEW;
  	} else  if (events) {
  		type = IPCTNL_MSG_CT_NEW;
  		group = NFNLGRP_CONNTRACK_UPDATE;
  	} else
  		return 0;
  
  	net = nf_ct_net(ct);
  	if (!item->report && !nfnetlink_has_listeners(net, group))
  		return 0;
  
  	skb = nlmsg_new(ctnetlink_nlmsg_size(ct), GFP_ATOMIC);
  	if (skb == NULL)
  		goto errout;
  
  	type |= NFNL_SUBSYS_CTNETLINK << 8;
  	nlh = nlmsg_put(skb, item->portid, 0, type, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = nf_ct_l3num(ct);
  	nfmsg->version	= NFNETLINK_V0;
  	nfmsg->res_id	= 0;
  
  	rcu_read_lock();
  	zone = nf_ct_zone(ct);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_ORIGINAL)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_ORIG) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_REPLY | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_REPLY)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_REPL) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	if (ctnetlink_dump_zone_id(skb, CTA_ZONE, zone,
  				   NF_CT_DEFAULT_ZONE_DIR) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_id(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_status(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (events & (1 << IPCT_DESTROY)) {
  		if (ctnetlink_dump_acct(skb, ct, type) < 0 ||
  		    ctnetlink_dump_timestamp(skb, ct) < 0)
  			goto nla_put_failure;
  	} else {
  		if (ctnetlink_dump_timeout(skb, ct) < 0)
  			goto nla_put_failure;
  
  		if (events & (1 << IPCT_PROTOINFO)
  		    && ctnetlink_dump_protoinfo(skb, ct) < 0)
  			goto nla_put_failure;
  
  		if ((events & (1 << IPCT_HELPER) || nfct_help(ct))
  		    && ctnetlink_dump_helpinfo(skb, ct) < 0)
  			goto nla_put_failure;
  
  #ifdef CONFIG_NF_CONNTRACK_SECMARK
  		if ((events & (1 << IPCT_SECMARK) || ct->secmark)
  		    && ctnetlink_dump_secctx(skb, ct) < 0)
  			goto nla_put_failure;
  #endif
  		if (events & (1 << IPCT_LABEL) &&
  		     ctnetlink_dump_labels(skb, ct) < 0)
  			goto nla_put_failure;
  
  		if (events & (1 << IPCT_RELATED) &&
  		    ctnetlink_dump_master(skb, ct) < 0)
  			goto nla_put_failure;
  
  		if (events & (1 << IPCT_SEQADJ) &&
  		    ctnetlink_dump_ct_seq_adj(skb, ct) < 0)
  			goto nla_put_failure;
  	}
  
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	if ((events & (1 << IPCT_MARK) || ct->mark)
  	    && ctnetlink_dump_mark(skb, ct) < 0)
  		goto nla_put_failure;
  #endif
  	rcu_read_unlock();
  
  	nlmsg_end(skb, nlh);
  	err = nfnetlink_send(skb, net, item->portid, group, item->report,
  			     GFP_ATOMIC);
  	if (err == -ENOBUFS || err == -EAGAIN)
  		return -ENOBUFS;
  
  	return 0;
  
  nla_put_failure:
  	rcu_read_unlock();
  	nlmsg_cancel(skb, nlh);
  nlmsg_failure:
  	kfree_skb(skb);
  errout:
  	if (nfnetlink_set_err(net, 0, group, -ENOBUFS) > 0)
  		return -ENOBUFS;
  
  	return 0;
  }
  #endif /* CONFIG_NF_CONNTRACK_EVENTS */
  
  static int ctnetlink_done(struct netlink_callback *cb)
  {
  	if (cb->args[1])
  		nf_ct_put((struct nf_conn *)cb->args[1]);
  	kfree(cb->data);
  	return 0;
  }
  
  struct ctnetlink_filter {
  	struct {
  		u_int32_t val;
  		u_int32_t mask;
  	} mark;
  };
  
  static struct ctnetlink_filter *
  ctnetlink_alloc_filter(const struct nlattr * const cda[])
  {
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	struct ctnetlink_filter *filter;
  
  	filter = kzalloc(sizeof(*filter), GFP_KERNEL);
  	if (filter == NULL)
  		return ERR_PTR(-ENOMEM);
  
  	filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK]));
  	filter->mark.mask = ntohl(nla_get_be32(cda[CTA_MARK_MASK]));
  
  	return filter;
  #else
  	return ERR_PTR(-EOPNOTSUPP);
  #endif
  }
  
  static int ctnetlink_filter_match(struct nf_conn *ct, void *data)
  {
  	struct ctnetlink_filter *filter = data;
  
  	if (filter == NULL)
  		return 1;
  
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	if ((ct->mark & filter->mark.mask) == filter->mark.val)
  		return 1;
  #endif
  
  	return 0;
  }
  
  static int
  ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	struct nf_conn *ct, *last;
  	struct nf_conntrack_tuple_hash *h;
  	struct hlist_nulls_node *n;
  	struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
  	u_int8_t l3proto = nfmsg->nfgen_family;
  	int res;
  	spinlock_t *lockp;
  
  	last = (struct nf_conn *)cb->args[1];
  
  	local_bh_disable();
  	for (; cb->args[0] < net->ct.htable_size; cb->args[0]++) {
  restart:
  		lockp = &nf_conntrack_locks[cb->args[0] % CONNTRACK_LOCKS];
  		nf_conntrack_lock(lockp);
  		if (cb->args[0] >= net->ct.htable_size) {
  			spin_unlock(lockp);
  			goto out;
  		}
  		hlist_nulls_for_each_entry(h, n, &net->ct.hash[cb->args[0]],
  					 hnnode) {
  			if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
  				continue;
  			ct = nf_ct_tuplehash_to_ctrack(h);
  			/* Dump entries of a given L3 protocol number.
  			 * If it is not specified, ie. l3proto == 0,
  			 * then dump everything. */
  			if (l3proto && nf_ct_l3num(ct) != l3proto)
  				continue;
  			if (cb->args[1]) {
  				if (ct != last)
  					continue;
  				cb->args[1] = 0;
  			}
  			if (!ctnetlink_filter_match(ct, cb->data))
  				continue;
  
  			rcu_read_lock();
  			res =
  			ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).portid,
  					    cb->nlh->nlmsg_seq,
  					    NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
  					    ct);
  			rcu_read_unlock();
  			if (res < 0) {
  				nf_conntrack_get(&ct->ct_general);
  				cb->args[1] = (unsigned long)ct;
  				spin_unlock(lockp);
  				goto out;
  			}
  		}
  		spin_unlock(lockp);
  		if (cb->args[1]) {
  			cb->args[1] = 0;
  			goto restart;
  		}
  	}
  out:
  	local_bh_enable();
  	if (last)
  		nf_ct_put(last);
  
  	return skb->len;
  }
  
  static inline int
  ctnetlink_parse_tuple_ip(struct nlattr *attr, struct nf_conntrack_tuple *tuple)
  {
  	struct nlattr *tb[CTA_IP_MAX+1];
  	struct nf_conntrack_l3proto *l3proto;
  	int ret = 0;
  
  	ret = nla_parse_nested(tb, CTA_IP_MAX, attr, NULL);
  	if (ret < 0)
  		return ret;
  
  	rcu_read_lock();
  	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);
  
  	if (likely(l3proto->nlattr_to_tuple)) {
  		ret = nla_validate_nested(attr, CTA_IP_MAX,
  					  l3proto->nla_policy);
  		if (ret == 0)
  			ret = l3proto->nlattr_to_tuple(tb, tuple);
  	}
  
  	rcu_read_unlock();
  
  	return ret;
  }
  
  static const struct nla_policy proto_nla_policy[CTA_PROTO_MAX+1] = {
  	[CTA_PROTO_NUM]	= { .type = NLA_U8 },
  };
  
  static inline int
  ctnetlink_parse_tuple_proto(struct nlattr *attr,
  			    struct nf_conntrack_tuple *tuple)
  {
  	struct nlattr *tb[CTA_PROTO_MAX+1];
  	struct nf_conntrack_l4proto *l4proto;
  	int ret = 0;
  
  	ret = nla_parse_nested(tb, CTA_PROTO_MAX, attr, proto_nla_policy);
  	if (ret < 0)
  		return ret;
  
  	if (!tb[CTA_PROTO_NUM])
  		return -EINVAL;
  	tuple->dst.protonum = nla_get_u8(tb[CTA_PROTO_NUM]);
  
  	rcu_read_lock();
  	l4proto = __nf_ct_l4proto_find(tuple->src.l3num, tuple->dst.protonum);
  
  	if (likely(l4proto->nlattr_to_tuple)) {
  		ret = nla_validate_nested(attr, CTA_PROTO_MAX,
  					  l4proto->nla_policy);
  		if (ret == 0)
  			ret = l4proto->nlattr_to_tuple(tb, tuple);
  	}
  
  	rcu_read_unlock();
  
  	return ret;
  }
  
  static int
  ctnetlink_parse_zone(const struct nlattr *attr,
  		     struct nf_conntrack_zone *zone)
  {
  	nf_ct_zone_init(zone, NF_CT_DEFAULT_ZONE_ID,
  			NF_CT_DEFAULT_ZONE_DIR, 0);
  #ifdef CONFIG_NF_CONNTRACK_ZONES
  	if (attr)
  		zone->id = ntohs(nla_get_be16(attr));
  #else
  	if (attr)
  		return -EOPNOTSUPP;
  #endif
  	return 0;
  }
  
  static int
  ctnetlink_parse_tuple_zone(struct nlattr *attr, enum ctattr_type type,
  			   struct nf_conntrack_zone *zone)
  {
  	int ret;
  
  	if (zone->id != NF_CT_DEFAULT_ZONE_ID)
  		return -EINVAL;
  
  	ret = ctnetlink_parse_zone(attr, zone);
  	if (ret < 0)
  		return ret;
  
  	if (type == CTA_TUPLE_REPLY)
  		zone->dir = NF_CT_ZONE_DIR_REPL;
  	else
  		zone->dir = NF_CT_ZONE_DIR_ORIG;
  
  	return 0;
  }
  
  static const struct nla_policy tuple_nla_policy[CTA_TUPLE_MAX+1] = {
  	[CTA_TUPLE_IP]		= { .type = NLA_NESTED },
  	[CTA_TUPLE_PROTO]	= { .type = NLA_NESTED },
  	[CTA_TUPLE_ZONE]	= { .type = NLA_U16 },
  };
  
  static int
  ctnetlink_parse_tuple(const struct nlattr * const cda[],
  		      struct nf_conntrack_tuple *tuple,
  		      enum ctattr_type type, u_int8_t l3num,
  		      struct nf_conntrack_zone *zone)
  {
  	struct nlattr *tb[CTA_TUPLE_MAX+1];
  	int err;
  
  	memset(tuple, 0, sizeof(*tuple));
  
  	err = nla_parse_nested(tb, CTA_TUPLE_MAX, cda[type], tuple_nla_policy);
  	if (err < 0)
  		return err;
  
  	if (!tb[CTA_TUPLE_IP])
  		return -EINVAL;
  
  	tuple->src.l3num = l3num;
  
  	err = ctnetlink_parse_tuple_ip(tb[CTA_TUPLE_IP], tuple);
  	if (err < 0)
  		return err;
  
  	if (!tb[CTA_TUPLE_PROTO])
  		return -EINVAL;
  
  	err = ctnetlink_parse_tuple_proto(tb[CTA_TUPLE_PROTO], tuple);
  	if (err < 0)
  		return err;
  
  	if (tb[CTA_TUPLE_ZONE]) {
  		if (!zone)
  			return -EINVAL;
  
  		err = ctnetlink_parse_tuple_zone(tb[CTA_TUPLE_ZONE],
  						 type, zone);
  		if (err < 0)
  			return err;
  	}
  
  	/* orig and expect tuples get DIR_ORIGINAL */
  	if (type == CTA_TUPLE_REPLY)
  		tuple->dst.dir = IP_CT_DIR_REPLY;
  	else
  		tuple->dst.dir = IP_CT_DIR_ORIGINAL;
  
  	return 0;
  }
  
  static const struct nla_policy help_nla_policy[CTA_HELP_MAX+1] = {
  	[CTA_HELP_NAME]		= { .type = NLA_NUL_STRING,
  				    .len = NF_CT_HELPER_NAME_LEN - 1 },
  };
  
  static inline int
  ctnetlink_parse_help(const struct nlattr *attr, char **helper_name,
  		     struct nlattr **helpinfo)
  {
  	int err;
  	struct nlattr *tb[CTA_HELP_MAX+1];
  
  	err = nla_parse_nested(tb, CTA_HELP_MAX, attr, help_nla_policy);
  	if (err < 0)
  		return err;
  
  	if (!tb[CTA_HELP_NAME])
  		return -EINVAL;
  
  	*helper_name = nla_data(tb[CTA_HELP_NAME]);
  
  	if (tb[CTA_HELP_INFO])
  		*helpinfo = tb[CTA_HELP_INFO];
  
  	return 0;
  }
  
  static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
  	[CTA_TUPLE_ORIG]	= { .type = NLA_NESTED },
  	[CTA_TUPLE_REPLY]	= { .type = NLA_NESTED },
  	[CTA_STATUS] 		= { .type = NLA_U32 },
  	[CTA_PROTOINFO]		= { .type = NLA_NESTED },
  	[CTA_HELP]		= { .type = NLA_NESTED },
  	[CTA_NAT_SRC]		= { .type = NLA_NESTED },
  	[CTA_TIMEOUT] 		= { .type = NLA_U32 },
  	[CTA_MARK]		= { .type = NLA_U32 },
  	[CTA_ID]		= { .type = NLA_U32 },
  	[CTA_NAT_DST]		= { .type = NLA_NESTED },
  	[CTA_TUPLE_MASTER]	= { .type = NLA_NESTED },
  	[CTA_NAT_SEQ_ADJ_ORIG]  = { .type = NLA_NESTED },
  	[CTA_NAT_SEQ_ADJ_REPLY] = { .type = NLA_NESTED },
  	[CTA_ZONE]		= { .type = NLA_U16 },
  	[CTA_MARK_MASK]		= { .type = NLA_U32 },
  	[CTA_LABELS]		= { .type = NLA_BINARY,
  				    .len = NF_CT_LABELS_MAX_SIZE },
  	[CTA_LABELS_MASK]	= { .type = NLA_BINARY,
  				    .len = NF_CT_LABELS_MAX_SIZE },
  };
  
  static int ctnetlink_flush_conntrack(struct net *net,
  				     const struct nlattr * const cda[],
  				     u32 portid, int report)
  {
  	struct ctnetlink_filter *filter = NULL;
  
  	if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
  		filter = ctnetlink_alloc_filter(cda);
  		if (IS_ERR(filter))
  			return PTR_ERR(filter);
  	}
  
  	nf_ct_iterate_cleanup(net, ctnetlink_filter_match, filter,
  			      portid, report);
  	kfree(filter);
  
  	return 0;
  }
  
  static int ctnetlink_del_conntrack(struct net *net, struct sock *ctnl,
  				   struct sk_buff *skb,
  				   const struct nlmsghdr *nlh,
  				   const struct nlattr * const cda[])
  {
  	struct nf_conntrack_tuple_hash *h;
  	struct nf_conntrack_tuple tuple;
  	struct nf_conn *ct;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	int err;
  
  	err = ctnetlink_parse_zone(cda[CTA_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	if (cda[CTA_TUPLE_ORIG])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_ORIG,
  					    u3, &zone);
  	else if (cda[CTA_TUPLE_REPLY])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_REPLY,
  					    u3, &zone);
  	else {
  		return ctnetlink_flush_conntrack(net, cda,
  						 NETLINK_CB(skb).portid,
  						 nlmsg_report(nlh));
  	}
  
  	if (err < 0)
  		return err;
  
  	h = nf_conntrack_find_get(net, &zone, &tuple);
  	if (!h)
  		return -ENOENT;
  
  	ct = nf_ct_tuplehash_to_ctrack(h);
  
  	if (cda[CTA_ID]) {
  		u_int32_t id = ntohl(nla_get_be32(cda[CTA_ID]));
  		if (id != (u32)(unsigned long)ct) {
  			nf_ct_put(ct);
  			return -ENOENT;
  		}
  	}
  
  	if (del_timer(&ct->timeout))
  		nf_ct_delete(ct, NETLINK_CB(skb).portid, nlmsg_report(nlh));
  
  	nf_ct_put(ct);
  
  	return 0;
  }
  
  static int ctnetlink_get_conntrack(struct net *net, struct sock *ctnl,
  				   struct sk_buff *skb,
  				   const struct nlmsghdr *nlh,
  				   const struct nlattr * const cda[])
  {
  	struct nf_conntrack_tuple_hash *h;
  	struct nf_conntrack_tuple tuple;
  	struct nf_conn *ct;
  	struct sk_buff *skb2 = NULL;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	int err;
  
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		struct netlink_dump_control c = {
  			.dump = ctnetlink_dump_table,
  			.done = ctnetlink_done,
  		};
  
  		if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
  			struct ctnetlink_filter *filter;
  
  			filter = ctnetlink_alloc_filter(cda);
  			if (IS_ERR(filter))
  				return PTR_ERR(filter);
  
  			c.data = filter;
  		}
  		return netlink_dump_start(ctnl, skb, nlh, &c);
  	}
  
  	err = ctnetlink_parse_zone(cda[CTA_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	if (cda[CTA_TUPLE_ORIG])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_ORIG,
  					    u3, &zone);
  	else if (cda[CTA_TUPLE_REPLY])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_REPLY,
  					    u3, &zone);
  	else
  		return -EINVAL;
  
  	if (err < 0)
  		return err;
  
  	h = nf_conntrack_find_get(net, &zone, &tuple);
  	if (!h)
  		return -ENOENT;
  
  	ct = nf_ct_tuplehash_to_ctrack(h);
  
  	err = -ENOMEM;
  	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
  	if (skb2 == NULL) {
  		nf_ct_put(ct);
  		return -ENOMEM;
  	}
  
  	rcu_read_lock();
  	err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).portid, nlh->nlmsg_seq,
  				  NFNL_MSG_TYPE(nlh->nlmsg_type), ct);
  	rcu_read_unlock();
  	nf_ct_put(ct);
  	if (err <= 0)
  		goto free;
  
  	err = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
  	if (err < 0)
  		goto out;
  
  	return 0;
  
  free:
  	kfree_skb(skb2);
  out:
  	/* this avoids a loop in nfnetlink. */
  	return err == -EAGAIN ? -ENOBUFS : err;
  }
  
  static int ctnetlink_done_list(struct netlink_callback *cb)
  {
  	if (cb->args[1])
  		nf_ct_put((struct nf_conn *)cb->args[1]);
  	return 0;
  }
  
  static int
  ctnetlink_dump_list(struct sk_buff *skb, struct netlink_callback *cb, bool dying)
  {
  	struct nf_conn *ct, *last;
  	struct nf_conntrack_tuple_hash *h;
  	struct hlist_nulls_node *n;
  	struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
  	u_int8_t l3proto = nfmsg->nfgen_family;
  	int res;
  	int cpu;
  	struct hlist_nulls_head *list;
  	struct net *net = sock_net(skb->sk);
  
  	if (cb->args[2])
  		return 0;
  
  	last = (struct nf_conn *)cb->args[1];
  
  	for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) {
  		struct ct_pcpu *pcpu;
  
  		if (!cpu_possible(cpu))
  			continue;
  
  		pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
  		spin_lock_bh(&pcpu->lock);
  		list = dying ? &pcpu->dying : &pcpu->unconfirmed;
  restart:
  		hlist_nulls_for_each_entry(h, n, list, hnnode) {
  			ct = nf_ct_tuplehash_to_ctrack(h);
  			if (l3proto && nf_ct_l3num(ct) != l3proto)
  				continue;
  			if (cb->args[1]) {
  				if (ct != last)
  					continue;
  				cb->args[1] = 0;
  			}
  			rcu_read_lock();
  			res = ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).portid,
  						  cb->nlh->nlmsg_seq,
  						  NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
  						  ct);
  			rcu_read_unlock();
  			if (res < 0) {
  				if (!atomic_inc_not_zero(&ct->ct_general.use))
  					continue;
  				cb->args[0] = cpu;
  				cb->args[1] = (unsigned long)ct;
  				spin_unlock_bh(&pcpu->lock);
  				goto out;
  			}
  		}
  		if (cb->args[1]) {
  			cb->args[1] = 0;
  			goto restart;
  		}
  		spin_unlock_bh(&pcpu->lock);
  	}
  	cb->args[2] = 1;
  out:
  	if (last)
  		nf_ct_put(last);
  
  	return skb->len;
  }
  
  static int
  ctnetlink_dump_dying(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	return ctnetlink_dump_list(skb, cb, true);
  }
  
  static int ctnetlink_get_ct_dying(struct net *net, struct sock *ctnl,
  				  struct sk_buff *skb,
  				  const struct nlmsghdr *nlh,
  				  const struct nlattr * const cda[])
  {
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		struct netlink_dump_control c = {
  			.dump = ctnetlink_dump_dying,
  			.done = ctnetlink_done_list,
  		};
  		return netlink_dump_start(ctnl, skb, nlh, &c);
  	}
  
  	return -EOPNOTSUPP;
  }
  
  static int
  ctnetlink_dump_unconfirmed(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	return ctnetlink_dump_list(skb, cb, false);
  }
  
  static int ctnetlink_get_ct_unconfirmed(struct net *net, struct sock *ctnl,
  					struct sk_buff *skb,
  					const struct nlmsghdr *nlh,
  					const struct nlattr * const cda[])
  {
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		struct netlink_dump_control c = {
  			.dump = ctnetlink_dump_unconfirmed,
  			.done = ctnetlink_done_list,
  		};
  		return netlink_dump_start(ctnl, skb, nlh, &c);
  	}
  
  	return -EOPNOTSUPP;
  }
  
  #ifdef CONFIG_NF_NAT_NEEDED
  static int
  ctnetlink_parse_nat_setup(struct nf_conn *ct,
  			  enum nf_nat_manip_type manip,
  			  const struct nlattr *attr)
  {
  	typeof(nfnetlink_parse_nat_setup_hook) parse_nat_setup;
  	int err;
  
  	parse_nat_setup = rcu_dereference(nfnetlink_parse_nat_setup_hook);
  	if (!parse_nat_setup) {
  #ifdef CONFIG_MODULES
  		rcu_read_unlock();
  		nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
  		if (request_module("nf-nat") < 0) {
  			nfnl_lock(NFNL_SUBSYS_CTNETLINK);
  			rcu_read_lock();
  			return -EOPNOTSUPP;
  		}
  		nfnl_lock(NFNL_SUBSYS_CTNETLINK);
  		rcu_read_lock();
  		if (nfnetlink_parse_nat_setup_hook)
  			return -EAGAIN;
  #endif
  		return -EOPNOTSUPP;
  	}
  
  	err = parse_nat_setup(ct, manip, attr);
  	if (err == -EAGAIN) {
  #ifdef CONFIG_MODULES
  		rcu_read_unlock();
  		nfnl_unlock(NFNL_SUBSYS_CTNETLINK);
  		if (request_module("nf-nat-%u", nf_ct_l3num(ct)) < 0) {
  			nfnl_lock(NFNL_SUBSYS_CTNETLINK);
  			rcu_read_lock();
  			return -EOPNOTSUPP;
  		}
  		nfnl_lock(NFNL_SUBSYS_CTNETLINK);
  		rcu_read_lock();
  #else
  		err = -EOPNOTSUPP;
  #endif
  	}
  	return err;
  }
  #endif
  
  static int
  ctnetlink_change_status(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  	unsigned long d;
  	unsigned int status = ntohl(nla_get_be32(cda[CTA_STATUS]));
  	d = ct->status ^ status;
  
  	if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
  		/* unchangeable */
  		return -EBUSY;
  
  	if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
  		/* SEEN_REPLY bit can only be set */
  		return -EBUSY;
  
  	if (d & IPS_ASSURED && !(status & IPS_ASSURED))
  		/* ASSURED bit can only be set */
  		return -EBUSY;
  
  	/* Be careful here, modifying NAT bits can screw up things,
  	 * so don't let users modify them directly if they don't pass
  	 * nf_nat_range. */
  	ct->status |= status & ~(IPS_NAT_DONE_MASK | IPS_NAT_MASK);
  	return 0;
  }
  
  static int
  ctnetlink_setup_nat(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  #ifdef CONFIG_NF_NAT_NEEDED
  	int ret;
  
  	if (!cda[CTA_NAT_DST] && !cda[CTA_NAT_SRC])
  		return 0;
  
  	ret = ctnetlink_parse_nat_setup(ct, NF_NAT_MANIP_DST,
  					cda[CTA_NAT_DST]);
  	if (ret < 0)
  		return ret;
  
  	ret = ctnetlink_parse_nat_setup(ct, NF_NAT_MANIP_SRC,
  					cda[CTA_NAT_SRC]);
  	return ret;
  #else
  	if (!cda[CTA_NAT_DST] && !cda[CTA_NAT_SRC])
  		return 0;
  	return -EOPNOTSUPP;
  #endif
  }
  
  static inline int
  ctnetlink_change_helper(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  	struct nf_conntrack_helper *helper;
  	struct nf_conn_help *help = nfct_help(ct);
  	char *helpname = NULL;
  	struct nlattr *helpinfo = NULL;
  	int err;
  
  	/* don't change helper of sibling connections */
  	if (ct->master)
  		return -EBUSY;
  
  	err = ctnetlink_parse_help(cda[CTA_HELP], &helpname, &helpinfo);
  	if (err < 0)
  		return err;
  
  	if (!strcmp(helpname, "")) {
  		if (help && help->helper) {
  			/* we had a helper before ... */
  			nf_ct_remove_expectations(ct);
  			RCU_INIT_POINTER(help->helper, NULL);
  		}
  
  		return 0;
  	}
  
  	helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
  					    nf_ct_protonum(ct));
  	if (helper == NULL) {
  #ifdef CONFIG_MODULES
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  
  		if (request_module("nfct-helper-%s", helpname) < 0) {
  			spin_lock_bh(&nf_conntrack_expect_lock);
  			return -EOPNOTSUPP;
  		}
  
  		spin_lock_bh(&nf_conntrack_expect_lock);
  		helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
  						    nf_ct_protonum(ct));
  		if (helper)
  			return -EAGAIN;
  #endif
  		return -EOPNOTSUPP;
  	}
  
  	if (help) {
  		if (help->helper == helper) {
  			/* update private helper data if allowed. */
  			if (helper->from_nlattr)
  				helper->from_nlattr(helpinfo, ct);
  			return 0;
  		} else
  			return -EBUSY;
  	}
  
  	/* we cannot set a helper for an existing conntrack */
  	return -EOPNOTSUPP;
  }
  
  static inline int
  ctnetlink_change_timeout(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  	u_int32_t timeout = ntohl(nla_get_be32(cda[CTA_TIMEOUT]));
  
  	if (!del_timer(&ct->timeout))
  		return -ETIME;
  
  	ct->timeout.expires = jiffies + timeout * HZ;
  	add_timer(&ct->timeout);
  
  	return 0;
  }
  
  static const struct nla_policy protoinfo_policy[CTA_PROTOINFO_MAX+1] = {
  	[CTA_PROTOINFO_TCP]	= { .type = NLA_NESTED },
  	[CTA_PROTOINFO_DCCP]	= { .type = NLA_NESTED },
  	[CTA_PROTOINFO_SCTP]	= { .type = NLA_NESTED },
  };
  
  static inline int
  ctnetlink_change_protoinfo(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  	const struct nlattr *attr = cda[CTA_PROTOINFO];
  	struct nlattr *tb[CTA_PROTOINFO_MAX+1];
  	struct nf_conntrack_l4proto *l4proto;
  	int err = 0;
  
  	err = nla_parse_nested(tb, CTA_PROTOINFO_MAX, attr, protoinfo_policy);
  	if (err < 0)
  		return err;
  
  	rcu_read_lock();
  	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
  	if (l4proto->from_nlattr)
  		err = l4proto->from_nlattr(tb, ct);
  	rcu_read_unlock();
  
  	return err;
  }
  
  static const struct nla_policy seqadj_policy[CTA_SEQADJ_MAX+1] = {
  	[CTA_SEQADJ_CORRECTION_POS]	= { .type = NLA_U32 },
  	[CTA_SEQADJ_OFFSET_BEFORE]	= { .type = NLA_U32 },
  	[CTA_SEQADJ_OFFSET_AFTER]	= { .type = NLA_U32 },
  };
  
  static inline int
  change_seq_adj(struct nf_ct_seqadj *seq, const struct nlattr * const attr)
  {
  	int err;
  	struct nlattr *cda[CTA_SEQADJ_MAX+1];
  
  	err = nla_parse_nested(cda, CTA_SEQADJ_MAX, attr, seqadj_policy);
  	if (err < 0)
  		return err;
  
  	if (!cda[CTA_SEQADJ_CORRECTION_POS])
  		return -EINVAL;
  
  	seq->correction_pos =
  		ntohl(nla_get_be32(cda[CTA_SEQADJ_CORRECTION_POS]));
  
  	if (!cda[CTA_SEQADJ_OFFSET_BEFORE])
  		return -EINVAL;
  
  	seq->offset_before =
  		ntohl(nla_get_be32(cda[CTA_SEQADJ_OFFSET_BEFORE]));
  
  	if (!cda[CTA_SEQADJ_OFFSET_AFTER])
  		return -EINVAL;
  
  	seq->offset_after =
  		ntohl(nla_get_be32(cda[CTA_SEQADJ_OFFSET_AFTER]));
  
  	return 0;
  }
  
  static int
  ctnetlink_change_seq_adj(struct nf_conn *ct,
  			 const struct nlattr * const cda[])
  {
  	struct nf_conn_seqadj *seqadj = nfct_seqadj(ct);
  	int ret = 0;
  
  	if (!seqadj)
  		return 0;
  
  	if (cda[CTA_SEQ_ADJ_ORIG]) {
  		ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_ORIGINAL],
  				     cda[CTA_SEQ_ADJ_ORIG]);
  		if (ret < 0)
  			return ret;
  
  		ct->status |= IPS_SEQ_ADJUST;
  	}
  
  	if (cda[CTA_SEQ_ADJ_REPLY]) {
  		ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_REPLY],
  				     cda[CTA_SEQ_ADJ_REPLY]);
  		if (ret < 0)
  			return ret;
  
  		ct->status |= IPS_SEQ_ADJUST;
  	}
  
  	return 0;
  }
  
  static int
  ctnetlink_attach_labels(struct nf_conn *ct, const struct nlattr * const cda[])
  {
  #ifdef CONFIG_NF_CONNTRACK_LABELS
  	size_t len = nla_len(cda[CTA_LABELS]);
  	const void *mask = cda[CTA_LABELS_MASK];
  
  	if (len & (sizeof(u32)-1)) /* must be multiple of u32 */
  		return -EINVAL;
  
  	if (mask) {
  		if (nla_len(cda[CTA_LABELS_MASK]) == 0 ||
  		    nla_len(cda[CTA_LABELS_MASK]) != len)
  			return -EINVAL;
  		mask = nla_data(cda[CTA_LABELS_MASK]);
  	}
  
  	len /= sizeof(u32);
  
  	return nf_connlabels_replace(ct, nla_data(cda[CTA_LABELS]), mask, len);
  #else
  	return -EOPNOTSUPP;
  #endif
  }
  
  static int
  ctnetlink_change_conntrack(struct nf_conn *ct,
  			   const struct nlattr * const cda[])
  {
  	int err;
  
  	/* only allow NAT changes and master assignation for new conntracks */
  	if (cda[CTA_NAT_SRC] || cda[CTA_NAT_DST] || cda[CTA_TUPLE_MASTER])
  		return -EOPNOTSUPP;
  
  	if (cda[CTA_HELP]) {
  		err = ctnetlink_change_helper(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_TIMEOUT]) {
  		err = ctnetlink_change_timeout(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_STATUS]) {
  		err = ctnetlink_change_status(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_PROTOINFO]) {
  		err = ctnetlink_change_protoinfo(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  #if defined(CONFIG_NF_CONNTRACK_MARK)
  	if (cda[CTA_MARK])
  		ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
  #endif
  
  	if (cda[CTA_SEQ_ADJ_ORIG] || cda[CTA_SEQ_ADJ_REPLY]) {
  		err = ctnetlink_change_seq_adj(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_LABELS]) {
  		err = ctnetlink_attach_labels(ct, cda);
  		if (err < 0)
  			return err;
  	}
  
  	return 0;
  }
  
  static struct nf_conn *
  ctnetlink_create_conntrack(struct net *net,
  			   const struct nf_conntrack_zone *zone,
  			   const struct nlattr * const cda[],
  			   struct nf_conntrack_tuple *otuple,
  			   struct nf_conntrack_tuple *rtuple,
  			   u8 u3)
  {
  	struct nf_conn *ct;
  	int err = -EINVAL;
  	struct nf_conntrack_helper *helper;
  	struct nf_conn_tstamp *tstamp;
  
  	ct = nf_conntrack_alloc(net, zone, otuple, rtuple, GFP_ATOMIC);
  	if (IS_ERR(ct))
  		return ERR_PTR(-ENOMEM);
  
  	if (!cda[CTA_TIMEOUT])
  		goto err1;
  	ct->timeout.expires = ntohl(nla_get_be32(cda[CTA_TIMEOUT]));
  
  	ct->timeout.expires = jiffies + ct->timeout.expires * HZ;
  
  	rcu_read_lock();
   	if (cda[CTA_HELP]) {
  		char *helpname = NULL;
  		struct nlattr *helpinfo = NULL;
  
  		err = ctnetlink_parse_help(cda[CTA_HELP], &helpname, &helpinfo);
   		if (err < 0)
  			goto err2;
  
  		helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
  						    nf_ct_protonum(ct));
  		if (helper == NULL) {
  			rcu_read_unlock();
  #ifdef CONFIG_MODULES
  			if (request_module("nfct-helper-%s", helpname) < 0) {
  				err = -EOPNOTSUPP;
  				goto err1;
  			}
  
  			rcu_read_lock();
  			helper = __nf_conntrack_helper_find(helpname,
  							    nf_ct_l3num(ct),
  							    nf_ct_protonum(ct));
  			if (helper) {
  				err = -EAGAIN;
  				goto err2;
  			}
  			rcu_read_unlock();
  #endif
  			err = -EOPNOTSUPP;
  			goto err1;
  		} else {
  			struct nf_conn_help *help;
  
  			help = nf_ct_helper_ext_add(ct, helper, GFP_ATOMIC);
  			if (help == NULL) {
  				err = -ENOMEM;
  				goto err2;
  			}
  			/* set private helper data if allowed. */
  			if (helper->from_nlattr)
  				helper->from_nlattr(helpinfo, ct);
  
  			/* not in hash table yet so not strictly necessary */
  			RCU_INIT_POINTER(help->helper, helper);
  		}
  	} else {
  		/* try an implicit helper assignation */
  		err = __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
  		if (err < 0)
  			goto err2;
  	}
  
  	err = ctnetlink_setup_nat(ct, cda);
  	if (err < 0)
  		goto err2;
  
  	nf_ct_acct_ext_add(ct, GFP_ATOMIC);
  	nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
  	nf_ct_ecache_ext_add(ct, 0, 0, GFP_ATOMIC);
  	nf_ct_labels_ext_add(ct);
  
  	/* we must add conntrack extensions before confirmation. */
  	ct->status |= IPS_CONFIRMED;
  
  	if (cda[CTA_STATUS]) {
  		err = ctnetlink_change_status(ct, cda);
  		if (err < 0)
  			goto err2;
  	}
  
  	if (cda[CTA_SEQ_ADJ_ORIG] || cda[CTA_SEQ_ADJ_REPLY]) {
  		err = ctnetlink_change_seq_adj(ct, cda);
  		if (err < 0)
  			goto err2;
  	}
  
  	memset(&ct->proto, 0, sizeof(ct->proto));
  	if (cda[CTA_PROTOINFO]) {
  		err = ctnetlink_change_protoinfo(ct, cda);
  		if (err < 0)
  			goto err2;
  	}
  
  #if defined(CONFIG_NF_CONNTRACK_MARK)
  	if (cda[CTA_MARK])
  		ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
  #endif
  
  	/* setup master conntrack: this is a confirmed expectation */
  	if (cda[CTA_TUPLE_MASTER]) {
  		struct nf_conntrack_tuple master;
  		struct nf_conntrack_tuple_hash *master_h;
  		struct nf_conn *master_ct;
  
  		err = ctnetlink_parse_tuple(cda, &master, CTA_TUPLE_MASTER,
  					    u3, NULL);
  		if (err < 0)
  			goto err2;
  
  		master_h = nf_conntrack_find_get(net, zone, &master);
  		if (master_h == NULL) {
  			err = -ENOENT;
  			goto err2;
  		}
  		master_ct = nf_ct_tuplehash_to_ctrack(master_h);
  		__set_bit(IPS_EXPECTED_BIT, &ct->status);
  		ct->master = master_ct;
  	}
  	tstamp = nf_conn_tstamp_find(ct);
  	if (tstamp)
  		tstamp->start = ktime_get_real_ns();
  
  	err = nf_conntrack_hash_check_insert(ct);
  	if (err < 0)
  		goto err2;
  
  	rcu_read_unlock();
  
  	return ct;
  
  err2:
  	rcu_read_unlock();
  err1:
  	nf_conntrack_free(ct);
  	return ERR_PTR(err);
  }
  
  static int ctnetlink_new_conntrack(struct net *net, struct sock *ctnl,
  				   struct sk_buff *skb,
  				   const struct nlmsghdr *nlh,
  				   const struct nlattr * const cda[])
  {
  	struct nf_conntrack_tuple otuple, rtuple;
  	struct nf_conntrack_tuple_hash *h = NULL;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	struct nf_conn *ct;
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	int err;
  
  	err = ctnetlink_parse_zone(cda[CTA_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	if (cda[CTA_TUPLE_ORIG]) {
  		err = ctnetlink_parse_tuple(cda, &otuple, CTA_TUPLE_ORIG,
  					    u3, &zone);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_TUPLE_REPLY]) {
  		err = ctnetlink_parse_tuple(cda, &rtuple, CTA_TUPLE_REPLY,
  					    u3, &zone);
  		if (err < 0)
  			return err;
  	}
  
  	if (cda[CTA_TUPLE_ORIG])
  		h = nf_conntrack_find_get(net, &zone, &otuple);
  	else if (cda[CTA_TUPLE_REPLY])
  		h = nf_conntrack_find_get(net, &zone, &rtuple);
  
  	if (h == NULL) {
  		err = -ENOENT;
  		if (nlh->nlmsg_flags & NLM_F_CREATE) {
  			enum ip_conntrack_events events;
  
  			if (!cda[CTA_TUPLE_ORIG] || !cda[CTA_TUPLE_REPLY])
  				return -EINVAL;
  
  			ct = ctnetlink_create_conntrack(net, &zone, cda, &otuple,
  							&rtuple, u3);
  			if (IS_ERR(ct))
  				return PTR_ERR(ct);
  
  			err = 0;
  			if (test_bit(IPS_EXPECTED_BIT, &ct->status))
  				events = IPCT_RELATED;
  			else
  				events = IPCT_NEW;
  
  			if (cda[CTA_LABELS] &&
  			    ctnetlink_attach_labels(ct, cda) == 0)
  				events |= (1 << IPCT_LABEL);
  
  			nf_conntrack_eventmask_report((1 << IPCT_REPLY) |
  						      (1 << IPCT_ASSURED) |
  						      (1 << IPCT_HELPER) |
  						      (1 << IPCT_PROTOINFO) |
  						      (1 << IPCT_SEQADJ) |
  						      (1 << IPCT_MARK) | events,
  						      ct, NETLINK_CB(skb).portid,
  						      nlmsg_report(nlh));
  			nf_ct_put(ct);
  		}
  
  		return err;
  	}
  	/* implicit 'else' */
  
  	err = -EEXIST;
  	ct = nf_ct_tuplehash_to_ctrack(h);
  	if (!(nlh->nlmsg_flags & NLM_F_EXCL)) {
  		spin_lock_bh(&nf_conntrack_expect_lock);
  		err = ctnetlink_change_conntrack(ct, cda);
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  		if (err == 0) {
  			nf_conntrack_eventmask_report((1 << IPCT_REPLY) |
  						      (1 << IPCT_ASSURED) |
  						      (1 << IPCT_HELPER) |
  						      (1 << IPCT_LABEL) |
  						      (1 << IPCT_PROTOINFO) |
  						      (1 << IPCT_SEQADJ) |
  						      (1 << IPCT_MARK),
  						      ct, NETLINK_CB(skb).portid,
  						      nlmsg_report(nlh));
  		}
  	}
  
  	nf_ct_put(ct);
  	return err;
  }
  
  static int
  ctnetlink_ct_stat_cpu_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
  				__u16 cpu, const struct ip_conntrack_stat *st)
  {
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	unsigned int flags = portid ? NLM_F_MULTI : 0, event;
  
  	event = (NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_CT_GET_STATS_CPU);
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = AF_UNSPEC;
  	nfmsg->version      = NFNETLINK_V0;
  	nfmsg->res_id	    = htons(cpu);
  
  	if (nla_put_be32(skb, CTA_STATS_SEARCHED, htonl(st->searched)) ||
  	    nla_put_be32(skb, CTA_STATS_FOUND, htonl(st->found)) ||
  	    nla_put_be32(skb, CTA_STATS_NEW, htonl(st->new)) ||
  	    nla_put_be32(skb, CTA_STATS_INVALID, htonl(st->invalid)) ||
  	    nla_put_be32(skb, CTA_STATS_IGNORE, htonl(st->ignore)) ||
  	    nla_put_be32(skb, CTA_STATS_DELETE, htonl(st->delete)) ||
  	    nla_put_be32(skb, CTA_STATS_DELETE_LIST, htonl(st->delete_list)) ||
  	    nla_put_be32(skb, CTA_STATS_INSERT, htonl(st->insert)) ||
  	    nla_put_be32(skb, CTA_STATS_INSERT_FAILED,
  				htonl(st->insert_failed)) ||
  	    nla_put_be32(skb, CTA_STATS_DROP, htonl(st->drop)) ||
  	    nla_put_be32(skb, CTA_STATS_EARLY_DROP, htonl(st->early_drop)) ||
  	    nla_put_be32(skb, CTA_STATS_ERROR, htonl(st->error)) ||
  	    nla_put_be32(skb, CTA_STATS_SEARCH_RESTART,
  				htonl(st->search_restart)))
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return skb->len;
  
  nla_put_failure:
  nlmsg_failure:
  	nlmsg_cancel(skb, nlh);
  	return -1;
  }
  
  static int
  ctnetlink_ct_stat_cpu_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	int cpu;
  	struct net *net = sock_net(skb->sk);
  
  	if (cb->args[0] == nr_cpu_ids)
  		return 0;
  
  	for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) {
  		const struct ip_conntrack_stat *st;
  
  		if (!cpu_possible(cpu))
  			continue;
  
  		st = per_cpu_ptr(net->ct.stat, cpu);
  		if (ctnetlink_ct_stat_cpu_fill_info(skb,
  						    NETLINK_CB(cb->skb).portid,
  						    cb->nlh->nlmsg_seq,
  						    cpu, st) < 0)
  				break;
  	}
  	cb->args[0] = cpu;
  
  	return skb->len;
  }
  
  static int ctnetlink_stat_ct_cpu(struct net *net, struct sock *ctnl,
  				 struct sk_buff *skb,
  				 const struct nlmsghdr *nlh,
  				 const struct nlattr * const cda[])
  {
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		struct netlink_dump_control c = {
  			.dump = ctnetlink_ct_stat_cpu_dump,
  		};
  		return netlink_dump_start(ctnl, skb, nlh, &c);
  	}
  
  	return 0;
  }
  
  static int
  ctnetlink_stat_ct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
  			    struct net *net)
  {
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	unsigned int flags = portid ? NLM_F_MULTI : 0, event;
  	unsigned int nr_conntracks = atomic_read(&net->ct.count);
  
  	event = (NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_CT_GET_STATS);
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = AF_UNSPEC;
  	nfmsg->version      = NFNETLINK_V0;
  	nfmsg->res_id	    = 0;
  
  	if (nla_put_be32(skb, CTA_STATS_GLOBAL_ENTRIES, htonl(nr_conntracks)))
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return skb->len;
  
  nla_put_failure:
  nlmsg_failure:
  	nlmsg_cancel(skb, nlh);
  	return -1;
  }
  
  static int ctnetlink_stat_ct(struct net *net, struct sock *ctnl,
  			     struct sk_buff *skb, const struct nlmsghdr *nlh,
  			     const struct nlattr * const cda[])
  {
  	struct sk_buff *skb2;
  	int err;
  
  	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
  	if (skb2 == NULL)
  		return -ENOMEM;
  
  	err = ctnetlink_stat_ct_fill_info(skb2, NETLINK_CB(skb).portid,
  					  nlh->nlmsg_seq,
  					  NFNL_MSG_TYPE(nlh->nlmsg_type),
  					  sock_net(skb->sk));
  	if (err <= 0)
  		goto free;
  
  	err = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
  	if (err < 0)
  		goto out;
  
  	return 0;
  
  free:
  	kfree_skb(skb2);
  out:
  	/* this avoids a loop in nfnetlink. */
  	return err == -EAGAIN ? -ENOBUFS : err;
  }
  
  static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = {
  	[CTA_EXPECT_MASTER]	= { .type = NLA_NESTED },
  	[CTA_EXPECT_TUPLE]	= { .type = NLA_NESTED },
  	[CTA_EXPECT_MASK]	= { .type = NLA_NESTED },
  	[CTA_EXPECT_TIMEOUT]	= { .type = NLA_U32 },
  	[CTA_EXPECT_ID]		= { .type = NLA_U32 },
  	[CTA_EXPECT_HELP_NAME]	= { .type = NLA_NUL_STRING,
  				    .len = NF_CT_HELPER_NAME_LEN - 1 },
  	[CTA_EXPECT_ZONE]	= { .type = NLA_U16 },
  	[CTA_EXPECT_FLAGS]	= { .type = NLA_U32 },
  	[CTA_EXPECT_CLASS]	= { .type = NLA_U32 },
  	[CTA_EXPECT_NAT]	= { .type = NLA_NESTED },
  	[CTA_EXPECT_FN]		= { .type = NLA_NUL_STRING },
  };
  
  static struct nf_conntrack_expect *
  ctnetlink_alloc_expect(const struct nlattr *const cda[], struct nf_conn *ct,
  		       struct nf_conntrack_helper *helper,
  		       struct nf_conntrack_tuple *tuple,
  		       struct nf_conntrack_tuple *mask);
  
  #ifdef CONFIG_NETFILTER_NETLINK_GLUE_CT
  static size_t
  ctnetlink_glue_build_size(const struct nf_conn *ct)
  {
  	return 3 * nla_total_size(0) /* CTA_TUPLE_ORIG|REPL|MASTER */
  	       + 3 * nla_total_size(0) /* CTA_TUPLE_IP */
  	       + 3 * nla_total_size(0) /* CTA_TUPLE_PROTO */
  	       + 3 * nla_total_size(sizeof(u_int8_t)) /* CTA_PROTO_NUM */
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_ID */
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_STATUS */
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_TIMEOUT */
  	       + nla_total_size(0) /* CTA_PROTOINFO */
  	       + nla_total_size(0) /* CTA_HELP */
  	       + nla_total_size(NF_CT_HELPER_NAME_LEN) /* CTA_HELP_NAME */
  	       + ctnetlink_secctx_size(ct)
  #ifdef CONFIG_NF_NAT_NEEDED
  	       + 2 * nla_total_size(0) /* CTA_NAT_SEQ_ADJ_ORIG|REPL */
  	       + 6 * nla_total_size(sizeof(u_int32_t)) /* CTA_NAT_SEQ_OFFSET */
  #endif
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	       + nla_total_size(sizeof(u_int32_t)) /* CTA_MARK */
  #endif
  #ifdef CONFIG_NF_CONNTRACK_ZONES
  	       + nla_total_size(sizeof(u_int16_t)) /* CTA_ZONE|CTA_TUPLE_ZONE */
  #endif
  	       + ctnetlink_proto_size(ct)
  	       ;
  }
  
  static struct nf_conn *ctnetlink_glue_get_ct(const struct sk_buff *skb,
  					     enum ip_conntrack_info *ctinfo)
  {
  	struct nf_conn *ct;
  
  	ct = nf_ct_get(skb, ctinfo);
  	if (ct && nf_ct_is_untracked(ct))
  		ct = NULL;
  
  	return ct;
  }
  
  static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct)
  {
  	const struct nf_conntrack_zone *zone;
  	struct nlattr *nest_parms;
  
  	rcu_read_lock();
  	zone = nf_ct_zone(ct);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_ORIGINAL)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_ORIG) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	nest_parms = nla_nest_start(skb, CTA_TUPLE_REPLY | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, nf_ct_tuple(ct, IP_CT_DIR_REPLY)) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_dump_zone_id(skb, CTA_TUPLE_ZONE, zone,
  				   NF_CT_ZONE_DIR_REPL) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	if (ctnetlink_dump_zone_id(skb, CTA_ZONE, zone,
  				   NF_CT_DEFAULT_ZONE_DIR) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_id(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_status(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_timeout(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_protoinfo(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if (ctnetlink_dump_helpinfo(skb, ct) < 0)
  		goto nla_put_failure;
  
  #ifdef CONFIG_NF_CONNTRACK_SECMARK
  	if (ct->secmark && ctnetlink_dump_secctx(skb, ct) < 0)
  		goto nla_put_failure;
  #endif
  	if (ct->master && ctnetlink_dump_master(skb, ct) < 0)
  		goto nla_put_failure;
  
  	if ((ct->status & IPS_SEQ_ADJUST) &&
  	    ctnetlink_dump_ct_seq_adj(skb, ct) < 0)
  		goto nla_put_failure;
  
  #ifdef CONFIG_NF_CONNTRACK_MARK
  	if (ct->mark && ctnetlink_dump_mark(skb, ct) < 0)
  		goto nla_put_failure;
  #endif
  	if (ctnetlink_dump_labels(skb, ct) < 0)
  		goto nla_put_failure;
  	rcu_read_unlock();
  	return 0;
  
  nla_put_failure:
  	rcu_read_unlock();
  	return -ENOSPC;
  }
  
  static int
  ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct,
  		     enum ip_conntrack_info ctinfo,
  		     u_int16_t ct_attr, u_int16_t ct_info_attr)
  {
  	struct nlattr *nest_parms;
  
  	nest_parms = nla_nest_start(skb, ct_attr | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  
  	if (__ctnetlink_glue_build(skb, ct) < 0)
  		goto nla_put_failure;
  
  	nla_nest_end(skb, nest_parms);
  
  	if (nla_put_be32(skb, ct_info_attr, htonl(ctinfo)))
  		goto nla_put_failure;
  
  	return 0;
  
  nla_put_failure:
  	return -ENOSPC;
  }
  
  static int
  ctnetlink_glue_parse_ct(const struct nlattr *cda[], struct nf_conn *ct)
  {
  	int err;
  
  	if (cda[CTA_TIMEOUT]) {
  		err = ctnetlink_change_timeout(ct, cda);
  		if (err < 0)
  			return err;
  	}
  	if (cda[CTA_STATUS]) {
  		err = ctnetlink_change_status(ct, cda);
  		if (err < 0)
  			return err;
  	}
  	if (cda[CTA_HELP]) {
  		err = ctnetlink_change_helper(ct, cda);
  		if (err < 0)
  			return err;
  	}
  	if (cda[CTA_LABELS]) {
  		err = ctnetlink_attach_labels(ct, cda);
  		if (err < 0)
  			return err;
  	}
  #if defined(CONFIG_NF_CONNTRACK_MARK)
  	if (cda[CTA_MARK]) {
  		u32 mask = 0, mark, newmark;
  		if (cda[CTA_MARK_MASK])
  			mask = ~ntohl(nla_get_be32(cda[CTA_MARK_MASK]));
  
  		mark = ntohl(nla_get_be32(cda[CTA_MARK]));
  		newmark = (ct->mark & mask) ^ mark;
  		if (newmark != ct->mark)
  			ct->mark = newmark;
  	}
  #endif
  	return 0;
  }
  
  static int
  ctnetlink_glue_parse(const struct nlattr *attr, struct nf_conn *ct)
  {
  	struct nlattr *cda[CTA_MAX+1];
  	int ret;
  
  	ret = nla_parse_nested(cda, CTA_MAX, attr, ct_nla_policy);
  	if (ret < 0)
  		return ret;
  
  	spin_lock_bh(&nf_conntrack_expect_lock);
  	ret = ctnetlink_glue_parse_ct((const struct nlattr **)cda, ct);
  	spin_unlock_bh(&nf_conntrack_expect_lock);
  
  	return ret;
  }
  
  static int ctnetlink_glue_exp_parse(const struct nlattr * const *cda,
  				    const struct nf_conn *ct,
  				    struct nf_conntrack_tuple *tuple,
  				    struct nf_conntrack_tuple *mask)
  {
  	int err;
  
  	err = ctnetlink_parse_tuple(cda, tuple, CTA_EXPECT_TUPLE,
  				    nf_ct_l3num(ct), NULL);
  	if (err < 0)
  		return err;
  
  	return ctnetlink_parse_tuple(cda, mask, CTA_EXPECT_MASK,
  				     nf_ct_l3num(ct), NULL);
  }
  
  static int
  ctnetlink_glue_attach_expect(const struct nlattr *attr, struct nf_conn *ct,
  			     u32 portid, u32 report)
  {
  	struct nlattr *cda[CTA_EXPECT_MAX+1];
  	struct nf_conntrack_tuple tuple, mask;
  	struct nf_conntrack_helper *helper = NULL;
  	struct nf_conntrack_expect *exp;
  	int err;
  
  	err = nla_parse_nested(cda, CTA_EXPECT_MAX, attr, exp_nla_policy);
  	if (err < 0)
  		return err;
  
  	err = ctnetlink_glue_exp_parse((const struct nlattr * const *)cda,
  				       ct, &tuple, &mask);
  	if (err < 0)
  		return err;
  
  	if (cda[CTA_EXPECT_HELP_NAME]) {
  		const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]);
  
  		helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
  						    nf_ct_protonum(ct));
  		if (helper == NULL)
  			return -EOPNOTSUPP;
  	}
  
  	exp = ctnetlink_alloc_expect((const struct nlattr * const *)cda, ct,
  				     helper, &tuple, &mask);
  	if (IS_ERR(exp))
  		return PTR_ERR(exp);
  
  	err = nf_ct_expect_related_report(exp, portid, report);
  	if (err < 0) {
  		nf_ct_expect_put(exp);
  		return err;
  	}
  
  	return 0;
  }
  
  static void ctnetlink_glue_seqadj(struct sk_buff *skb, struct nf_conn *ct,
  				  enum ip_conntrack_info ctinfo, int diff)
  {
  	if (!(ct->status & IPS_NAT_MASK))
  		return;
  
  	nf_ct_tcp_seqadj_set(skb, ct, ctinfo, diff);
  }
  
  static struct nfnl_ct_hook ctnetlink_glue_hook = {
  	.get_ct		= ctnetlink_glue_get_ct,
  	.build_size	= ctnetlink_glue_build_size,
  	.build		= ctnetlink_glue_build,
  	.parse		= ctnetlink_glue_parse,
  	.attach_expect	= ctnetlink_glue_attach_expect,
  	.seq_adjust	= ctnetlink_glue_seqadj,
  };
  #endif /* CONFIG_NETFILTER_NETLINK_GLUE_CT */
  
  /***********************************************************************
   * EXPECT
   ***********************************************************************/
  
  static inline int
  ctnetlink_exp_dump_tuple(struct sk_buff *skb,
  			 const struct nf_conntrack_tuple *tuple,
  			 enum ctattr_expect type)
  {
  	struct nlattr *nest_parms;
  
  	nest_parms = nla_nest_start(skb, type | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  	if (ctnetlink_dump_tuples(skb, tuple) < 0)
  		goto nla_put_failure;
  	nla_nest_end(skb, nest_parms);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static inline int
  ctnetlink_exp_dump_mask(struct sk_buff *skb,
  			const struct nf_conntrack_tuple *tuple,
  			const struct nf_conntrack_tuple_mask *mask)
  {
  	int ret;
  	struct nf_conntrack_l3proto *l3proto;
  	struct nf_conntrack_l4proto *l4proto;
  	struct nf_conntrack_tuple m;
  	struct nlattr *nest_parms;
  
  	memset(&m, 0xFF, sizeof(m));
  	memcpy(&m.src.u3, &mask->src.u3, sizeof(m.src.u3));
  	m.src.u.all = mask->src.u.all;
  	m.dst.protonum = tuple->dst.protonum;
  
  	nest_parms = nla_nest_start(skb, CTA_EXPECT_MASK | NLA_F_NESTED);
  	if (!nest_parms)
  		goto nla_put_failure;
  
  	rcu_read_lock();
  	l3proto = __nf_ct_l3proto_find(tuple->src.l3num);
  	ret = ctnetlink_dump_tuples_ip(skb, &m, l3proto);
  	if (ret >= 0) {
  		l4proto = __nf_ct_l4proto_find(tuple->src.l3num,
  					       tuple->dst.protonum);
  	ret = ctnetlink_dump_tuples_proto(skb, &m, l4proto);
  	}
  	rcu_read_unlock();
  
  	if (unlikely(ret < 0))
  		goto nla_put_failure;
  
  	nla_nest_end(skb, nest_parms);
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static const union nf_inet_addr any_addr;
  
  static int
  ctnetlink_exp_dump_expect(struct sk_buff *skb,
  			  const struct nf_conntrack_expect *exp)
  {
  	struct nf_conn *master = exp->master;
  	long timeout = ((long)exp->timeout.expires - (long)jiffies) / HZ;
  	struct nf_conn_help *help;
  #ifdef CONFIG_NF_NAT_NEEDED
  	struct nlattr *nest_parms;
  	struct nf_conntrack_tuple nat_tuple = {};
  #endif
  	struct nf_ct_helper_expectfn *expfn;
  
  	if (timeout < 0)
  		timeout = 0;
  
  	if (ctnetlink_exp_dump_tuple(skb, &exp->tuple, CTA_EXPECT_TUPLE) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_exp_dump_mask(skb, &exp->tuple, &exp->mask) < 0)
  		goto nla_put_failure;
  	if (ctnetlink_exp_dump_tuple(skb,
  				 &master->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
  				 CTA_EXPECT_MASTER) < 0)
  		goto nla_put_failure;
  
  #ifdef CONFIG_NF_NAT_NEEDED
  	if (!nf_inet_addr_cmp(&exp->saved_addr, &any_addr) ||
  	    exp->saved_proto.all) {
  		nest_parms = nla_nest_start(skb, CTA_EXPECT_NAT | NLA_F_NESTED);
  		if (!nest_parms)
  			goto nla_put_failure;
  
  		if (nla_put_be32(skb, CTA_EXPECT_NAT_DIR, htonl(exp->dir)))
  			goto nla_put_failure;
  
  		nat_tuple.src.l3num = nf_ct_l3num(master);
  		nat_tuple.src.u3 = exp->saved_addr;
  		nat_tuple.dst.protonum = nf_ct_protonum(master);
  		nat_tuple.src.u = exp->saved_proto;
  
  		if (ctnetlink_exp_dump_tuple(skb, &nat_tuple,
  						CTA_EXPECT_NAT_TUPLE) < 0)
  	                goto nla_put_failure;
  	        nla_nest_end(skb, nest_parms);
  	}
  #endif
  	if (nla_put_be32(skb, CTA_EXPECT_TIMEOUT, htonl(timeout)) ||
  	    nla_put_be32(skb, CTA_EXPECT_ID, htonl((unsigned long)exp)) ||
  	    nla_put_be32(skb, CTA_EXPECT_FLAGS, htonl(exp->flags)) ||
  	    nla_put_be32(skb, CTA_EXPECT_CLASS, htonl(exp->class)))
  		goto nla_put_failure;
  	help = nfct_help(master);
  	if (help) {
  		struct nf_conntrack_helper *helper;
  
  		helper = rcu_dereference(help->helper);
  		if (helper &&
  		    nla_put_string(skb, CTA_EXPECT_HELP_NAME, helper->name))
  			goto nla_put_failure;
  	}
  	expfn = nf_ct_helper_expectfn_find_by_symbol(exp->expectfn);
  	if (expfn != NULL &&
  	    nla_put_string(skb, CTA_EXPECT_FN, expfn->name))
  		goto nla_put_failure;
  
  	return 0;
  
  nla_put_failure:
  	return -1;
  }
  
  static int
  ctnetlink_exp_fill_info(struct sk_buff *skb, u32 portid, u32 seq,
  			int event, const struct nf_conntrack_expect *exp)
  {
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	unsigned int flags = portid ? NLM_F_MULTI : 0;
  
  	event |= NFNL_SUBSYS_CTNETLINK_EXP << 8;
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = exp->tuple.src.l3num;
  	nfmsg->version	    = NFNETLINK_V0;
  	nfmsg->res_id	    = 0;
  
  	if (ctnetlink_exp_dump_expect(skb, exp) < 0)
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return skb->len;
  
  nlmsg_failure:
  nla_put_failure:
  	nlmsg_cancel(skb, nlh);
  	return -1;
  }
  
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  static int
  ctnetlink_expect_event(unsigned int events, struct nf_exp_event *item)
  {
  	struct nf_conntrack_expect *exp = item->exp;
  	struct net *net = nf_ct_exp_net(exp);
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	struct sk_buff *skb;
  	unsigned int type, group;
  	int flags = 0;
  
  	if (events & (1 << IPEXP_DESTROY)) {
  		type = IPCTNL_MSG_EXP_DELETE;
  		group = NFNLGRP_CONNTRACK_EXP_DESTROY;
  	} else if (events & (1 << IPEXP_NEW)) {
  		type = IPCTNL_MSG_EXP_NEW;
  		flags = NLM_F_CREATE|NLM_F_EXCL;
  		group = NFNLGRP_CONNTRACK_EXP_NEW;
  	} else
  		return 0;
  
  	if (!item->report && !nfnetlink_has_listeners(net, group))
  		return 0;
  
  	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
  	if (skb == NULL)
  		goto errout;
  
  	type |= NFNL_SUBSYS_CTNETLINK_EXP << 8;
  	nlh = nlmsg_put(skb, item->portid, 0, type, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = exp->tuple.src.l3num;
  	nfmsg->version	    = NFNETLINK_V0;
  	nfmsg->res_id	    = 0;
  
  	rcu_read_lock();
  	if (ctnetlink_exp_dump_expect(skb, exp) < 0)
  		goto nla_put_failure;
  	rcu_read_unlock();
  
  	nlmsg_end(skb, nlh);
  	nfnetlink_send(skb, net, item->portid, group, item->report, GFP_ATOMIC);
  	return 0;
  
  nla_put_failure:
  	rcu_read_unlock();
  	nlmsg_cancel(skb, nlh);
  nlmsg_failure:
  	kfree_skb(skb);
  errout:
  	nfnetlink_set_err(net, 0, 0, -ENOBUFS);
  	return 0;
  }
  #endif
  static int ctnetlink_exp_done(struct netlink_callback *cb)
  {
  	if (cb->args[1])
  		nf_ct_expect_put((struct nf_conntrack_expect *)cb->args[1]);
  	return 0;
  }
  
  static int
  ctnetlink_exp_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct net *net = sock_net(skb->sk);
  	struct nf_conntrack_expect *exp, *last;
  	struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
  	u_int8_t l3proto = nfmsg->nfgen_family;
  
  	rcu_read_lock();
  	last = (struct nf_conntrack_expect *)cb->args[1];
  	for (; cb->args[0] < nf_ct_expect_hsize; cb->args[0]++) {
  restart:
  		hlist_for_each_entry(exp, &net->ct.expect_hash[cb->args[0]],
  				     hnode) {
  			if (l3proto && exp->tuple.src.l3num != l3proto)
  				continue;
  			if (cb->args[1]) {
  				if (exp != last)
  					continue;
  				cb->args[1] = 0;
  			}
  			if (ctnetlink_exp_fill_info(skb,
  						    NETLINK_CB(cb->skb).portid,
  						    cb->nlh->nlmsg_seq,
  						    IPCTNL_MSG_EXP_NEW,
  						    exp) < 0) {
  				if (!atomic_inc_not_zero(&exp->use))
  					continue;
  				cb->args[1] = (unsigned long)exp;
  				goto out;
  			}
  		}
  		if (cb->args[1]) {
  			cb->args[1] = 0;
  			goto restart;
  		}
  	}
  out:
  	rcu_read_unlock();
  	if (last)
  		nf_ct_expect_put(last);
  
  	return skb->len;
  }
  
  static int
  ctnetlink_exp_ct_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	struct nf_conntrack_expect *exp, *last;
  	struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
  	struct nf_conn *ct = cb->data;
  	struct nf_conn_help *help = nfct_help(ct);
  	u_int8_t l3proto = nfmsg->nfgen_family;
  
  	if (cb->args[0])
  		return 0;
  
  	rcu_read_lock();
  	last = (struct nf_conntrack_expect *)cb->args[1];
  restart:
  	hlist_for_each_entry(exp, &help->expectations, lnode) {
  		if (l3proto && exp->tuple.src.l3num != l3proto)
  			continue;
  		if (cb->args[1]) {
  			if (exp != last)
  				continue;
  			cb->args[1] = 0;
  		}
  		if (ctnetlink_exp_fill_info(skb, NETLINK_CB(cb->skb).portid,
  					    cb->nlh->nlmsg_seq,
  					    IPCTNL_MSG_EXP_NEW,
  					    exp) < 0) {
  			if (!atomic_inc_not_zero(&exp->use))
  				continue;
  			cb->args[1] = (unsigned long)exp;
  			goto out;
  		}
  	}
  	if (cb->args[1]) {
  		cb->args[1] = 0;
  		goto restart;
  	}
  	cb->args[0] = 1;
  out:
  	rcu_read_unlock();
  	if (last)
  		nf_ct_expect_put(last);
  
  	return skb->len;
  }
  
  static int ctnetlink_dump_exp_ct(struct net *net, struct sock *ctnl,
  				 struct sk_buff *skb,
  				 const struct nlmsghdr *nlh,
  				 const struct nlattr * const cda[])
  {
  	int err;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_tuple tuple;
  	struct nf_conntrack_tuple_hash *h;
  	struct nf_conn *ct;
  	struct nf_conntrack_zone zone;
  	struct netlink_dump_control c = {
  		.dump = ctnetlink_exp_ct_dump_table,
  		.done = ctnetlink_exp_done,
  	};
  
  	err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_MASTER,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  
  	err = ctnetlink_parse_zone(cda[CTA_EXPECT_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	h = nf_conntrack_find_get(net, &zone, &tuple);
  	if (!h)
  		return -ENOENT;
  
  	ct = nf_ct_tuplehash_to_ctrack(h);
  	c.data = ct;
  
  	err = netlink_dump_start(ctnl, skb, nlh, &c);
  	nf_ct_put(ct);
  
  	return err;
  }
  
  static int ctnetlink_get_expect(struct net *net, struct sock *ctnl,
  				struct sk_buff *skb, const struct nlmsghdr *nlh,
  				const struct nlattr * const cda[])
  {
  	struct nf_conntrack_tuple tuple;
  	struct nf_conntrack_expect *exp;
  	struct sk_buff *skb2;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	int err;
  
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		if (cda[CTA_EXPECT_MASTER])
  			return ctnetlink_dump_exp_ct(net, ctnl, skb, nlh, cda);
  		else {
  			struct netlink_dump_control c = {
  				.dump = ctnetlink_exp_dump_table,
  				.done = ctnetlink_exp_done,
  			};
  			return netlink_dump_start(ctnl, skb, nlh, &c);
  		}
  	}
  
  	err = ctnetlink_parse_zone(cda[CTA_EXPECT_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	if (cda[CTA_EXPECT_TUPLE])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE,
  					    u3, NULL);
  	else if (cda[CTA_EXPECT_MASTER])
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_MASTER,
  					    u3, NULL);
  	else
  		return -EINVAL;
  
  	if (err < 0)
  		return err;
  
  	exp = nf_ct_expect_find_get(net, &zone, &tuple);
  	if (!exp)
  		return -ENOENT;
  
  	if (cda[CTA_EXPECT_ID]) {
  		__be32 id = nla_get_be32(cda[CTA_EXPECT_ID]);
  		if (ntohl(id) != (u32)(unsigned long)exp) {
  			nf_ct_expect_put(exp);
  			return -ENOENT;
  		}
  	}
  
  	err = -ENOMEM;
  	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
  	if (skb2 == NULL) {
  		nf_ct_expect_put(exp);
  		goto out;
  	}
  
  	rcu_read_lock();
  	err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).portid,
  				      nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW, exp);
  	rcu_read_unlock();
  	nf_ct_expect_put(exp);
  	if (err <= 0)
  		goto free;
  
  	err = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
  	if (err < 0)
  		goto out;
  
  	return 0;
  
  free:
  	kfree_skb(skb2);
  out:
  	/* this avoids a loop in nfnetlink. */
  	return err == -EAGAIN ? -ENOBUFS : err;
  }
  
  static int ctnetlink_del_expect(struct net *net, struct sock *ctnl,
  				struct sk_buff *skb, const struct nlmsghdr *nlh,
  				const struct nlattr * const cda[])
  {
  	struct nf_conntrack_expect *exp;
  	struct nf_conntrack_tuple tuple;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	struct hlist_node *next;
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	unsigned int i;
  	int err;
  
  	if (cda[CTA_EXPECT_TUPLE]) {
  		/* delete a single expect by tuple */
  		err = ctnetlink_parse_zone(cda[CTA_EXPECT_ZONE], &zone);
  		if (err < 0)
  			return err;
  
  		err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE,
  					    u3, NULL);
  		if (err < 0)
  			return err;
  
  		/* bump usage count to 2 */
  		exp = nf_ct_expect_find_get(net, &zone, &tuple);
  		if (!exp)
  			return -ENOENT;
  
  		if (cda[CTA_EXPECT_ID]) {
  			__be32 id = nla_get_be32(cda[CTA_EXPECT_ID]);
  			if (ntohl(id) != (u32)(unsigned long)exp) {
  				nf_ct_expect_put(exp);
  				return -ENOENT;
  			}
  		}
  
  		/* after list removal, usage count == 1 */
  		spin_lock_bh(&nf_conntrack_expect_lock);
  		if (del_timer(&exp->timeout)) {
  			nf_ct_unlink_expect_report(exp, NETLINK_CB(skb).portid,
  						   nlmsg_report(nlh));
  			nf_ct_expect_put(exp);
  		}
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  		/* have to put what we 'get' above.
  		 * after this line usage count == 0 */
  		nf_ct_expect_put(exp);
  	} else if (cda[CTA_EXPECT_HELP_NAME]) {
  		char *name = nla_data(cda[CTA_EXPECT_HELP_NAME]);
  		struct nf_conn_help *m_help;
  
  		/* delete all expectations for this helper */
  		spin_lock_bh(&nf_conntrack_expect_lock);
  		for (i = 0; i < nf_ct_expect_hsize; i++) {
  			hlist_for_each_entry_safe(exp, next,
  						  &net->ct.expect_hash[i],
  						  hnode) {
  				m_help = nfct_help(exp->master);
  				if (!strcmp(m_help->helper->name, name) &&
  				    del_timer(&exp->timeout)) {
  					nf_ct_unlink_expect_report(exp,
  							NETLINK_CB(skb).portid,
  							nlmsg_report(nlh));
  					nf_ct_expect_put(exp);
  				}
  			}
  		}
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  	} else {
  		/* This basically means we have to flush everything*/
  		spin_lock_bh(&nf_conntrack_expect_lock);
  		for (i = 0; i < nf_ct_expect_hsize; i++) {
  			hlist_for_each_entry_safe(exp, next,
  						  &net->ct.expect_hash[i],
  						  hnode) {
  				if (del_timer(&exp->timeout)) {
  					nf_ct_unlink_expect_report(exp,
  							NETLINK_CB(skb).portid,
  							nlmsg_report(nlh));
  					nf_ct_expect_put(exp);
  				}
  			}
  		}
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  	}
  
  	return 0;
  }
  static int
  ctnetlink_change_expect(struct nf_conntrack_expect *x,
  			const struct nlattr * const cda[])
  {
  	if (cda[CTA_EXPECT_TIMEOUT]) {
  		if (!del_timer(&x->timeout))
  			return -ETIME;
  
  		x->timeout.expires = jiffies +
  			ntohl(nla_get_be32(cda[CTA_EXPECT_TIMEOUT])) * HZ;
  		add_timer(&x->timeout);
  	}
  	return 0;
  }
  
  static const struct nla_policy exp_nat_nla_policy[CTA_EXPECT_NAT_MAX+1] = {
  	[CTA_EXPECT_NAT_DIR]	= { .type = NLA_U32 },
  	[CTA_EXPECT_NAT_TUPLE]	= { .type = NLA_NESTED },
  };
  
  static int
  ctnetlink_parse_expect_nat(const struct nlattr *attr,
  			   struct nf_conntrack_expect *exp,
  			   u_int8_t u3)
  {
  #ifdef CONFIG_NF_NAT_NEEDED
  	struct nlattr *tb[CTA_EXPECT_NAT_MAX+1];
  	struct nf_conntrack_tuple nat_tuple = {};
  	int err;
  
  	err = nla_parse_nested(tb, CTA_EXPECT_NAT_MAX, attr, exp_nat_nla_policy);
  	if (err < 0)
  		return err;
  
  	if (!tb[CTA_EXPECT_NAT_DIR] || !tb[CTA_EXPECT_NAT_TUPLE])
  		return -EINVAL;
  
  	err = ctnetlink_parse_tuple((const struct nlattr * const *)tb,
  				    &nat_tuple, CTA_EXPECT_NAT_TUPLE,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  
  	exp->saved_addr = nat_tuple.src.u3;
  	exp->saved_proto = nat_tuple.src.u;
  	exp->dir = ntohl(nla_get_be32(tb[CTA_EXPECT_NAT_DIR]));
  
  	return 0;
  #else
  	return -EOPNOTSUPP;
  #endif
  }
  
  static struct nf_conntrack_expect *
  ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct,
  		       struct nf_conntrack_helper *helper,
  		       struct nf_conntrack_tuple *tuple,
  		       struct nf_conntrack_tuple *mask)
  {
  	u_int32_t class = 0;
  	struct nf_conntrack_expect *exp;
  	struct nf_conn_help *help;
  	int err;
  
  	if (cda[CTA_EXPECT_CLASS] && helper) {
  		class = ntohl(nla_get_be32(cda[CTA_EXPECT_CLASS]));
  		if (class > helper->expect_class_max)
  			return ERR_PTR(-EINVAL);
  	}
  	exp = nf_ct_expect_alloc(ct);
  	if (!exp)
  		return ERR_PTR(-ENOMEM);
  
  	help = nfct_help(ct);
  	if (!help) {
  		if (!cda[CTA_EXPECT_TIMEOUT]) {
  			err = -EINVAL;
  			goto err_out;
  		}
  		exp->timeout.expires =
  		  jiffies + ntohl(nla_get_be32(cda[CTA_EXPECT_TIMEOUT])) * HZ;
  
  		exp->flags = NF_CT_EXPECT_USERSPACE;
  		if (cda[CTA_EXPECT_FLAGS]) {
  			exp->flags |=
  				ntohl(nla_get_be32(cda[CTA_EXPECT_FLAGS]));
  		}
  	} else {
  		if (cda[CTA_EXPECT_FLAGS]) {
  			exp->flags = ntohl(nla_get_be32(cda[CTA_EXPECT_FLAGS]));
  			exp->flags &= ~NF_CT_EXPECT_USERSPACE;
  		} else
  			exp->flags = 0;
  	}
  	if (cda[CTA_EXPECT_FN]) {
  		const char *name = nla_data(cda[CTA_EXPECT_FN]);
  		struct nf_ct_helper_expectfn *expfn;
  
  		expfn = nf_ct_helper_expectfn_find_by_name(name);
  		if (expfn == NULL) {
  			err = -EINVAL;
  			goto err_out;
  		}
  		exp->expectfn = expfn->expectfn;
  	} else
  		exp->expectfn = NULL;
  
  	exp->class = class;
  	exp->master = ct;
  	exp->helper = helper;
  	exp->tuple = *tuple;
  	exp->mask.src.u3 = mask->src.u3;
  	exp->mask.src.u.all = mask->src.u.all;
  
  	if (cda[CTA_EXPECT_NAT]) {
  		err = ctnetlink_parse_expect_nat(cda[CTA_EXPECT_NAT],
  						 exp, nf_ct_l3num(ct));
  		if (err < 0)
  			goto err_out;
  	}
  	return exp;
  err_out:
  	nf_ct_expect_put(exp);
  	return ERR_PTR(err);
  }
  
  static int
  ctnetlink_create_expect(struct net *net,
  			const struct nf_conntrack_zone *zone,
  			const struct nlattr * const cda[],
  			u_int8_t u3, u32 portid, int report)
  {
  	struct nf_conntrack_tuple tuple, mask, master_tuple;
  	struct nf_conntrack_tuple_hash *h = NULL;
  	struct nf_conntrack_helper *helper = NULL;
  	struct nf_conntrack_expect *exp;
  	struct nf_conn *ct;
  	int err;
  
  	/* caller guarantees that those three CTA_EXPECT_* exist */
  	err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  	err = ctnetlink_parse_tuple(cda, &mask, CTA_EXPECT_MASK,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  	err = ctnetlink_parse_tuple(cda, &master_tuple, CTA_EXPECT_MASTER,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  
  	/* Look for master conntrack of this expectation */
  	h = nf_conntrack_find_get(net, zone, &master_tuple);
  	if (!h)
  		return -ENOENT;
  	ct = nf_ct_tuplehash_to_ctrack(h);
  
  	if (cda[CTA_EXPECT_HELP_NAME]) {
  		const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]);
  
  		helper = __nf_conntrack_helper_find(helpname, u3,
  						    nf_ct_protonum(ct));
  		if (helper == NULL) {
  #ifdef CONFIG_MODULES
  			if (request_module("nfct-helper-%s", helpname) < 0) {
  				err = -EOPNOTSUPP;
  				goto err_ct;
  			}
  			helper = __nf_conntrack_helper_find(helpname, u3,
  							    nf_ct_protonum(ct));
  			if (helper) {
  				err = -EAGAIN;
  				goto err_ct;
  			}
  #endif
  			err = -EOPNOTSUPP;
  			goto err_ct;
  		}
  	}
  
  	exp = ctnetlink_alloc_expect(cda, ct, helper, &tuple, &mask);
  	if (IS_ERR(exp)) {
  		err = PTR_ERR(exp);
  		goto err_ct;
  	}
  
  	err = nf_ct_expect_related_report(exp, portid, report);
  	nf_ct_expect_put(exp);
  err_ct:
  	nf_ct_put(ct);
  	return err;
  }
  
  static int ctnetlink_new_expect(struct net *net, struct sock *ctnl,
  				struct sk_buff *skb, const struct nlmsghdr *nlh,
  				const struct nlattr * const cda[])
  {
  	struct nf_conntrack_tuple tuple;
  	struct nf_conntrack_expect *exp;
  	struct nfgenmsg *nfmsg = nlmsg_data(nlh);
  	u_int8_t u3 = nfmsg->nfgen_family;
  	struct nf_conntrack_zone zone;
  	int err;
  
  	if (!cda[CTA_EXPECT_TUPLE]
  	    || !cda[CTA_EXPECT_MASK]
  	    || !cda[CTA_EXPECT_MASTER])
  		return -EINVAL;
  
  	err = ctnetlink_parse_zone(cda[CTA_EXPECT_ZONE], &zone);
  	if (err < 0)
  		return err;
  
  	err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE,
  				    u3, NULL);
  	if (err < 0)
  		return err;
  
  	spin_lock_bh(&nf_conntrack_expect_lock);
  	exp = __nf_ct_expect_find(net, &zone, &tuple);
  	if (!exp) {
  		spin_unlock_bh(&nf_conntrack_expect_lock);
  		err = -ENOENT;
  		if (nlh->nlmsg_flags & NLM_F_CREATE) {
  			err = ctnetlink_create_expect(net, &zone, cda, u3,
  						      NETLINK_CB(skb).portid,
  						      nlmsg_report(nlh));
  		}
  		return err;
  	}
  
  	err = -EEXIST;
  	if (!(nlh->nlmsg_flags & NLM_F_EXCL))
  		err = ctnetlink_change_expect(exp, cda);
  	spin_unlock_bh(&nf_conntrack_expect_lock);
  
  	return err;
  }
  
  static int
  ctnetlink_exp_stat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, int cpu,
  			     const struct ip_conntrack_stat *st)
  {
  	struct nlmsghdr *nlh;
  	struct nfgenmsg *nfmsg;
  	unsigned int flags = portid ? NLM_F_MULTI : 0, event;
  
  	event = (NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_EXP_GET_STATS_CPU);
  	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
  	if (nlh == NULL)
  		goto nlmsg_failure;
  
  	nfmsg = nlmsg_data(nlh);
  	nfmsg->nfgen_family = AF_UNSPEC;
  	nfmsg->version      = NFNETLINK_V0;
  	nfmsg->res_id	    = htons(cpu);
  
  	if (nla_put_be32(skb, CTA_STATS_EXP_NEW, htonl(st->expect_new)) ||
  	    nla_put_be32(skb, CTA_STATS_EXP_CREATE, htonl(st->expect_create)) ||
  	    nla_put_be32(skb, CTA_STATS_EXP_DELETE, htonl(st->expect_delete)))
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  	return skb->len;
  
  nla_put_failure:
  nlmsg_failure:
  	nlmsg_cancel(skb, nlh);
  	return -1;
  }
  
  static int
  ctnetlink_exp_stat_cpu_dump(struct sk_buff *skb, struct netlink_callback *cb)
  {
  	int cpu;
  	struct net *net = sock_net(skb->sk);
  
  	if (cb->args[0] == nr_cpu_ids)
  		return 0;
  
  	for (cpu = cb->args[0]; cpu < nr_cpu_ids; cpu++) {
  		const struct ip_conntrack_stat *st;
  
  		if (!cpu_possible(cpu))
  			continue;
  
  		st = per_cpu_ptr(net->ct.stat, cpu);
  		if (ctnetlink_exp_stat_fill_info(skb, NETLINK_CB(cb->skb).portid,
  						 cb->nlh->nlmsg_seq,
  						 cpu, st) < 0)
  			break;
  	}
  	cb->args[0] = cpu;
  
  	return skb->len;
  }
  
  static int ctnetlink_stat_exp_cpu(struct net *net, struct sock *ctnl,
  				  struct sk_buff *skb,
  				  const struct nlmsghdr *nlh,
  				  const struct nlattr * const cda[])
  {
  	if (nlh->nlmsg_flags & NLM_F_DUMP) {
  		struct netlink_dump_control c = {
  			.dump = ctnetlink_exp_stat_cpu_dump,
  		};
  		return netlink_dump_start(ctnl, skb, nlh, &c);
  	}
  
  	return 0;
  }
  
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  static struct nf_ct_event_notifier ctnl_notifier = {
  	.fcn = ctnetlink_conntrack_event,
  };
  
  static struct nf_exp_event_notifier ctnl_notifier_exp = {
  	.fcn = ctnetlink_expect_event,
  };
  #endif
  
  static const struct nfnl_callback ctnl_cb[IPCTNL_MSG_MAX] = {
  	[IPCTNL_MSG_CT_NEW]		= { .call = ctnetlink_new_conntrack,
  					    .attr_count = CTA_MAX,
  					    .policy = ct_nla_policy },
  	[IPCTNL_MSG_CT_GET] 		= { .call = ctnetlink_get_conntrack,
  					    .attr_count = CTA_MAX,
  					    .policy = ct_nla_policy },
  	[IPCTNL_MSG_CT_DELETE]  	= { .call = ctnetlink_del_conntrack,
  					    .attr_count = CTA_MAX,
  					    .policy = ct_nla_policy },
  	[IPCTNL_MSG_CT_GET_CTRZERO] 	= { .call = ctnetlink_get_conntrack,
  					    .attr_count = CTA_MAX,
  					    .policy = ct_nla_policy },
  	[IPCTNL_MSG_CT_GET_STATS_CPU]	= { .call = ctnetlink_stat_ct_cpu },
  	[IPCTNL_MSG_CT_GET_STATS]	= { .call = ctnetlink_stat_ct },
  	[IPCTNL_MSG_CT_GET_DYING]	= { .call = ctnetlink_get_ct_dying },
  	[IPCTNL_MSG_CT_GET_UNCONFIRMED]	= { .call = ctnetlink_get_ct_unconfirmed },
  };
  
  static const struct nfnl_callback ctnl_exp_cb[IPCTNL_MSG_EXP_MAX] = {
  	[IPCTNL_MSG_EXP_GET]		= { .call = ctnetlink_get_expect,
  					    .attr_count = CTA_EXPECT_MAX,
  					    .policy = exp_nla_policy },
  	[IPCTNL_MSG_EXP_NEW]		= { .call = ctnetlink_new_expect,
  					    .attr_count = CTA_EXPECT_MAX,
  					    .policy = exp_nla_policy },
  	[IPCTNL_MSG_EXP_DELETE]		= { .call = ctnetlink_del_expect,
  					    .attr_count = CTA_EXPECT_MAX,
  					    .policy = exp_nla_policy },
  	[IPCTNL_MSG_EXP_GET_STATS_CPU]	= { .call = ctnetlink_stat_exp_cpu },
  };
  
  static const struct nfnetlink_subsystem ctnl_subsys = {
  	.name				= "conntrack",
  	.subsys_id			= NFNL_SUBSYS_CTNETLINK,
  	.cb_count			= IPCTNL_MSG_MAX,
  	.cb				= ctnl_cb,
  };
  
  static const struct nfnetlink_subsystem ctnl_exp_subsys = {
  	.name				= "conntrack_expect",
  	.subsys_id			= NFNL_SUBSYS_CTNETLINK_EXP,
  	.cb_count			= IPCTNL_MSG_EXP_MAX,
  	.cb				= ctnl_exp_cb,
  };
  
  MODULE_ALIAS("ip_conntrack_netlink");
  MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK);
  MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_EXP);
  
  static int __net_init ctnetlink_net_init(struct net *net)
  {
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  	int ret;
  
  	ret = nf_conntrack_register_notifier(net, &ctnl_notifier);
  	if (ret < 0) {
  		pr_err("ctnetlink_init: cannot register notifier.\n");
  		goto err_out;
  	}
  
  	ret = nf_ct_expect_register_notifier(net, &ctnl_notifier_exp);
  	if (ret < 0) {
  		pr_err("ctnetlink_init: cannot expect register notifier.\n");
  		goto err_unreg_notifier;
  	}
  #endif
  	return 0;
  
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  err_unreg_notifier:
  	nf_conntrack_unregister_notifier(net, &ctnl_notifier);
  err_out:
  	return ret;
  #endif
  }
  
  static void ctnetlink_net_exit(struct net *net)
  {
  #ifdef CONFIG_NF_CONNTRACK_EVENTS
  	nf_ct_expect_unregister_notifier(net, &ctnl_notifier_exp);
  	nf_conntrack_unregister_notifier(net, &ctnl_notifier);
  #endif
  }
  
  static void __net_exit ctnetlink_net_exit_batch(struct list_head *net_exit_list)
  {
  	struct net *net;
  
  	list_for_each_entry(net, net_exit_list, exit_list)
  		ctnetlink_net_exit(net);
  }
  
  static struct pernet_operations ctnetlink_net_ops = {
  	.init		= ctnetlink_net_init,
  	.exit_batch	= ctnetlink_net_exit_batch,
  };
  
  static int __init ctnetlink_init(void)
  {
  	int ret;
  
  	pr_info("ctnetlink v%s: registering with nfnetlink.\n", version);
  	ret = nfnetlink_subsys_register(&ctnl_subsys);
  	if (ret < 0) {
  		pr_err("ctnetlink_init: cannot register with nfnetlink.\n");
  		goto err_out;
  	}
  
  	ret = nfnetlink_subsys_register(&ctnl_exp_subsys);
  	if (ret < 0) {
  		pr_err("ctnetlink_init: cannot register exp with nfnetlink.\n");
  		goto err_unreg_subsys;
  	}
  
  	ret = register_pernet_subsys(&ctnetlink_net_ops);
  	if (ret < 0) {
  		pr_err("ctnetlink_init: cannot register pernet operations\n");
  		goto err_unreg_exp_subsys;
  	}
  #ifdef CONFIG_NETFILTER_NETLINK_GLUE_CT
  	/* setup interaction between nf_queue and nf_conntrack_netlink. */
  	RCU_INIT_POINTER(nfnl_ct_hook, &ctnetlink_glue_hook);
  #endif
  	return 0;
  
  err_unreg_exp_subsys:
  	nfnetlink_subsys_unregister(&ctnl_exp_subsys);
  err_unreg_subsys:
  	nfnetlink_subsys_unregister(&ctnl_subsys);
  err_out:
  	return ret;
  }
  
  static void __exit ctnetlink_exit(void)
  {
  	pr_info("ctnetlink: unregistering from nfnetlink.\n");
  
  	unregister_pernet_subsys(&ctnetlink_net_ops);
  	nfnetlink_subsys_unregister(&ctnl_exp_subsys);
  	nfnetlink_subsys_unregister(&ctnl_subsys);
  #ifdef CONFIG_NETFILTER_NETLINK_GLUE_CT
  	RCU_INIT_POINTER(nfnl_ct_hook, NULL);
  #endif
  }
  
  module_init(ctnetlink_init);
  module_exit(ctnetlink_exit);
  