/* 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>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <net/netfilter/nf_conntrack_synproxy.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 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 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 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 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 int ctnetlink_dump_timeout(struct sk_buff *skb, const struct nf_conn *ct)
{
        long timeout = nf_ct_expires(ct) / HZ;

        if (nla_put_be32(skb, CTA_TIMEOUT, htonl(timeout)))
                goto nla_put_failure;
        return 0;

nla_put_failure:
        return -1;
}

static 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 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),
                         CTA_COUNTERS_PAD) ||
            nla_put_be64(skb, CTA_COUNTERS_BYTES, cpu_to_be64(bytes),
                         CTA_COUNTERS_PAD))
                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),
                         CTA_TIMESTAMP_PAD) ||
            (tstamp->stop != 0 && nla_put_be64(skb, CTA_TIMESTAMP_STOP,
                                               cpu_to_be64(tstamp->stop),
                                               CTA_TIMESTAMP_PAD)))
                goto nla_put_failure;
        nla_nest_end(skb, nest_count);

        return 0;

nla_put_failure:
        return -1;
}

#ifdef CONFIG_NF_CONNTRACK_MARK
static 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 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 inline 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(sizeof(labels->bits));
}

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 i;

        if (!labels)
                return 0;

        i = 0;
        do {
                if (labels->bits[i] != 0)
                        return nla_put(skb, CTA_LABELS, sizeof(labels->bits),
                                       labels->bits);
                i++;
        } while (i < ARRAY_SIZE(labels->bits));

        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 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 int ctnetlink_dump_ct_seq_adj(struct sk_buff *skb, 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;

        spin_lock_bh(&ct->lock);
        seq = &seqadj->seq[IP_CT_DIR_ORIGINAL];
        if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_ORIG) == -1)
                goto err;

        seq = &seqadj->seq[IP_CT_DIR_REPLY];
        if (dump_ct_seq_adj(skb, seq, CTA_SEQ_ADJ_REPLY) == -1)
                goto err;

        spin_unlock_bh(&ct->lock);
        return 0;
err:
        spin_unlock_bh(&ct->lock);
        return -1;
}

static 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 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_msg_type(NFNL_SUBSYS_CTNETLINK, 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_64bit(sizeof(uint64_t)) /* CTA_COUNTERS_PACKETS */
               + 2 * nla_total_size_64bit(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_64bit(sizeof(uint64_t));
#else
        return 0;
#endif
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS
static 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)
               ;
}

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;

        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_msg_type(NFNL_SUBSYS_CTNETLINK, type);
        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;
        struct nf_conn *nf_ct_evict[8];
        int res, i;
        spinlock_t *lockp;

        last = (struct nf_conn *)cb->args[1];
        i = 0;

        local_bh_disable();
        for (; cb->args[0] < nf_conntrack_htable_size; cb->args[0]++) {
restart:
                while (i) {
                        i--;
                        if (nf_ct_should_gc(nf_ct_evict[i]))
                                nf_ct_kill(nf_ct_evict[i]);
                        nf_ct_put(nf_ct_evict[i]);
                }

                lockp = &nf_conntrack_locks[cb->args[0] % CONNTRACK_LOCKS];
                nf_conntrack_lock(lockp);
                if (cb->args[0] >= nf_conntrack_htable_size) {
                        spin_unlock(lockp);
                        goto out;
                }
                hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[cb->args[0]],
                                           hnnode) {
                        if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
                                continue;
                        ct = nf_ct_tuplehash_to_ctrack(h);
                        if (nf_ct_is_expired(ct)) {
                                if (i < ARRAY_SIZE(nf_ct_evict) &&
                                    atomic_inc_not_zero(&ct->ct_general.use))
                                        nf_ct_evict[i++] = ct;
                                continue;
                        }

                        if (!net_eq(net, nf_ct_net(ct)))
                                continue;

                        /* 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 hash resize happened, now clear the leftover. */
                if ((struct nf_conn *)cb->args[1] == last)
                        cb->args[1] = 0;

                nf_ct_put(last);
        }

        while (i) {
                i--;
                if (nf_ct_should_gc(nf_ct_evict[i]))
                        nf_ct_kill(nf_ct_evict[i]);
                nf_ct_put(nf_ct_evict[i]);
        }

        return skb->len;
}

static 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, 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, NULL);
                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 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,
                               NULL);
        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, NULL);
                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, u32 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,
                               NULL);
        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 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, NULL);
        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(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 netlink_ext_ack *extack)
{
        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;
                }
        }

        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 netlink_ext_ack *extack)
{
        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[],
                                  struct netlink_ext_ack *extack)
{
        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[],
                                        struct netlink_ext_ack *extack)
{
        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 void
__ctnetlink_change_status(struct nf_conn *ct, unsigned long on,
                          unsigned long off)
{
        unsigned int bit;

        /* Ignore these unchangable bits */
        on &= ~IPS_UNCHANGEABLE_MASK;
        off &= ~IPS_UNCHANGEABLE_MASK;

        for (bit = 0; bit < __IPS_MAX_BIT; bit++) {
                if (on & (1 << bit))
                        set_bit(bit, &ct->status);
                else if (off & (1 << bit))
                        clear_bit(bit, &ct->status);
        }
}

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;

        __ctnetlink_change_status(ct, status, 0);
        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 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;

        err = ctnetlink_parse_help(cda[CTA_HELP], &helpname, &helpinfo);
        if (err < 0)
                return err;

        /* don't change helper of sibling connections */
        if (ct->master) {
                /* If we try to change the helper to the same thing twice,
                 * treat the second attempt as a no-op instead of returning
                 * an error.
                 */
                err = -EBUSY;
                if (help) {
                        rcu_read_lock();
                        helper = rcu_dereference(help->helper);
                        if (helper && !strcmp(helper->name, helpname))
                                err = 0;
                        rcu_read_unlock();
                }

                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;
        }

        rcu_read_lock();
        helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct),
                                            nf_ct_protonum(ct));
        if (helper == NULL) {
                rcu_read_unlock();
                return -EOPNOTSUPP;
        }

        if (help) {
                if (help->helper == helper) {
                        /* update private helper data if allowed. */
                        if (helper->from_nlattr)
                                helper->from_nlattr(helpinfo, ct);
                        err = 0;
                } else
                        err = -EBUSY;
        } else {
                /* we cannot set a helper for an existing conntrack */
                err = -EOPNOTSUPP;
        }

        rcu_read_unlock();
        return err;
}

static int ctnetlink_change_timeout(struct nf_conn *ct,
                                    const struct nlattr * const cda[])
{
        u_int32_t timeout = ntohl(nla_get_be32(cda[CTA_TIMEOUT]));

        ct->timeout = nfct_time_stamp + timeout * HZ;

        if (test_bit(IPS_DYING_BIT, &ct->status))
                return -ETIME;

        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 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,
                               NULL);
        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 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, NULL);
        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;

        spin_lock_bh(&ct->lock);
        if (cda[CTA_SEQ_ADJ_ORIG]) {
                ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_ORIGINAL],
                                     cda[CTA_SEQ_ADJ_ORIG]);
                if (ret < 0)
                        goto err;

                set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
        }

        if (cda[CTA_SEQ_ADJ_REPLY]) {
                ret = change_seq_adj(&seqadj->seq[IP_CT_DIR_REPLY],
                                     cda[CTA_SEQ_ADJ_REPLY]);
                if (ret < 0)
                        goto err;

                set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
        }

        spin_unlock_bh(&ct->lock);
        return 0;
err:
        spin_unlock_bh(&ct->lock);
        return ret;
}

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 = nfct_time_stamp + ntohl(nla_get_be32(cda[CTA_TIMEOUT])) * 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);
        nfct_seqadj_ext_add(ct);
        nfct_synproxy_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 netlink_ext_ack *extack)
{
        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;
                        if (otuple.dst.protonum != rtuple.dst.protonum)
                                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 = 1 << IPCT_RELATED;
                        else
                                events = 1 << 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)) {
                err = ctnetlink_change_conntrack(ct, cda);
                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_msg_type(NFNL_SUBSYS_CTNETLINK,
                              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_FOUND, htonl(st->found)) ||
            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_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[],
                                 struct netlink_ext_ack *extack)
{
        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_msg_type(NFNL_SUBSYS_CTNETLINK, 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 netlink_ext_ack *extack)
{
        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)
{
        return nf_ct_get(skb, ctinfo);
}

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_update_status(struct nf_conn *ct, const struct nlattr * const cda[])
{
        unsigned int status = ntohl(nla_get_be32(cda[CTA_STATUS]));
        unsigned long d = ct->status ^ status;

        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;

        /* This check is less strict than ctnetlink_change_status()
         * because callers often flip IPS_EXPECTED bits when sending
         * an NFQA_CT attribute to the kernel.  So ignore the
         * unchangeable bits but do not error out. Also user programs
         * are allowed to clear the bits that they are allowed to change.
         */
        __ctnetlink_change_status(ct, status, ~status);
        return 0;
}

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_update_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, NULL);
        if (ret < 0)
                return ret;

        return ctnetlink_glue_parse_ct((const struct nlattr **)cda, ct);
}

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,
                               NULL);
        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);
        nf_ct_expect_put(exp);
        return err;
}

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 int ctnetlink_exp_dump_tuple(struct sk_buff *skb,
                                    const struct nf_conntrack_tuple *tuple,
                                    u32 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 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_msg_type(NFNL_SUBSYS_CTNETLINK_EXP, event);
        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_msg_type(NFNL_SUBSYS_CTNETLINK_EXP, type);
        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_rcu(exp, &nf_ct_expect_hash[cb->args[0]],
                                         hnode) {
                        if (l3proto && exp->tuple.src.l3num != l3proto)
                                continue;

                        if (!net_eq(nf_ct_net(exp->master), net))
                                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 (!refcount_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_rcu(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 (!refcount_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[],
                                 struct netlink_ext_ack *extack)
{
        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);
        /* No expectation linked to this connection tracking. */
        if (!nfct_help(ct)) {
                nf_ct_put(ct);
                return 0;
        }

        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 netlink_ext_ack *extack)
{
        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,
                                                     extack);
                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 netlink_ext_ack *extack)
{
        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,
                                                  &nf_ct_expect_hash[i],
                                                  hnode) {

                                if (!net_eq(nf_ct_exp_net(exp), net))
                                        continue;

                                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,
                                                  &nf_ct_expect_hash[i],
                                                  hnode) {

                                if (!net_eq(nf_ct_exp_net(exp), net))
                                        continue;

                                if (del_timer(&exp->timeout)) {
                                        nf_ct_unlink_expect_report(exp,
                                                        NETLINK_CB(skb).portid,