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root/net/netfilter/nf_conntrack_netlink.c

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DEFINITIONS

This source file includes following definitions.
  1. ctnetlink_dump_tuples_proto
  2. ctnetlink_dump_tuples_ip
  3. ctnetlink_dump_tuples
  4. ctnetlink_dump_status
  5. ctnetlink_dump_timeout
  6. ctnetlink_dump_protoinfo
  7. ctnetlink_dump_helpinfo
  8. ctnetlink_dump_counters
  9. ctnetlink_dump_mark
  10. ctnetlink_dump_secmark
  11. ctnetlink_dump_master
  12. dump_nat_seq_adj
  13. ctnetlink_dump_nat_seq_adj
  14. ctnetlink_dump_id
  15. ctnetlink_dump_use
  16. ctnetlink_fill_info
  17. ctnetlink_conntrack_event
  18. ctnetlink_done
  19. ctnetlink_dump_table
  20. ctnetlink_parse_tuple_ip
  21. ctnetlink_parse_tuple_proto
  22. ctnetlink_parse_tuple
  23. nfnetlink_parse_nat_proto
  24. nfnetlink_parse_nat
  25. ctnetlink_parse_help
  26. ctnetlink_del_conntrack
  27. ctnetlink_get_conntrack
  28. ctnetlink_change_status
  29. ctnetlink_change_helper
  30. ctnetlink_change_timeout
  31. ctnetlink_change_protoinfo
  32. change_nat_seq_adj
  33. ctnetlink_change_nat_seq_adj
  34. ctnetlink_change_conntrack
  35. ctnetlink_create_conntrack
  36. ctnetlink_new_conntrack
  37. ctnetlink_exp_dump_tuple
  38. ctnetlink_exp_dump_mask
  39. ctnetlink_exp_dump_expect
  40. ctnetlink_exp_fill_info
  41. ctnetlink_expect_event
  42. ctnetlink_exp_done
  43. ctnetlink_exp_dump_table
  44. ctnetlink_get_expect
  45. ctnetlink_del_expect
  46. ctnetlink_change_expect
  47. ctnetlink_create_expect
  48. ctnetlink_new_expect
  49. ctnetlink_init
  50. ctnetlink_exit

/* 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) 2005-2008 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/types.h>
#include <linux/timer.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/netlink.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>

#include <linux/netfilter.h>
#include <net/netlink.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_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_acct.h>
#ifdef CONFIG_NF_NAT_NEEDED
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_protocol.h>
#endif

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>

MODULE_LICENSE("GPL");

static char __initdata version[] = "0.93";

static inline int
ctnetlink_dump_tuples_proto(struct sk_buff *skb,
                            const struct nf_conntrack_tuple *tuple,
                            struct nf_conntrack_l4proto *l4proto)
{
        int ret = 0;
        struct nlattr *nest_parms;

        nest_parms = nla_nest_start(skb, CTA_TUPLE_PROTO | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;
        NLA_PUT_U8(skb, CTA_PROTO_NUM, tuple->dst.protonum);

        if (likely(l4proto->tuple_to_nlattr))
                ret = l4proto->tuple_to_nlattr(skb, tuple);

        nla_nest_end(skb, nest_parms);

        return ret;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_dump_tuples_ip(struct sk_buff *skb,
                         const struct nf_conntrack_tuple *tuple,
                         struct nf_conntrack_l3proto *l3proto)
{
        int ret = 0;
        struct nlattr *nest_parms;

        nest_parms = nla_nest_start(skb, CTA_TUPLE_IP | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;

        if (likely(l3proto->tuple_to_nlattr))
                ret = l3proto->tuple_to_nlattr(skb, tuple);

        nla_nest_end(skb, nest_parms);

        return ret;

nla_put_failure:
        return -1;
}

static int
ctnetlink_dump_tuples(struct sk_buff *skb,
                      const struct nf_conntrack_tuple *tuple)
{
        int ret;
        struct nf_conntrack_l3proto *l3proto;
        struct nf_conntrack_l4proto *l4proto;

        l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);
        ret = ctnetlink_dump_tuples_ip(skb, tuple, l3proto);
        nf_ct_l3proto_put(l3proto);

        if (unlikely(ret < 0))
                return ret;

        l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);
        ret = ctnetlink_dump_tuples_proto(skb, tuple, l4proto);
        nf_ct_l4proto_put(l4proto);

        return ret;
}

static inline int
ctnetlink_dump_status(struct sk_buff *skb, const struct nf_conn *ct)
{
        NLA_PUT_BE32(skb, CTA_STATUS, htonl(ct->status));
        return 0;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_dump_timeout(struct sk_buff *skb, const struct nf_conn *ct)
{
        long timeout = (ct->timeout.expires - jiffies) / HZ;

        if (timeout < 0)
                timeout = 0;

        NLA_PUT_BE32(skb, CTA_TIMEOUT, htonl(timeout));
        return 0;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_dump_protoinfo(struct sk_buff *skb, const struct nf_conn *ct)
{
        struct nf_conntrack_l4proto *l4proto;
        struct nlattr *nest_proto;
        int ret;

        l4proto = nf_ct_l4proto_find_get(nf_ct_l3num(ct), nf_ct_protonum(ct));
        if (!l4proto->to_nlattr) {
                nf_ct_l4proto_put(l4proto);
                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);

        nf_ct_l4proto_put(l4proto);

        nla_nest_end(skb, nest_proto);

        return ret;

nla_put_failure:
        nf_ct_l4proto_put(l4proto);
        return -1;
}

static inline int
ctnetlink_dump_helpinfo(struct sk_buff *skb, const struct nf_conn *ct)
{
        struct nlattr *nest_helper;
        const struct nf_conn_help *help = nfct_help(ct);
        struct nf_conntrack_helper *helper;

        if (!help)
                return 0;

        rcu_read_lock();
        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;
        NLA_PUT_STRING(skb, CTA_HELP_NAME, helper->name);

        if (helper->to_nlattr)
                helper->to_nlattr(skb, ct);

        nla_nest_end(skb, nest_helper);
out:
        rcu_read_unlock();
        return 0;

nla_put_failure:
        rcu_read_unlock();
        return -1;
}

static int
ctnetlink_dump_counters(struct sk_buff *skb, const struct nf_conn *ct,
                        enum ip_conntrack_dir dir)
{
        enum ctattr_type type = dir ? CTA_COUNTERS_REPLY: CTA_COUNTERS_ORIG;
        struct nlattr *nest_count;
        const struct nf_conn_counter *acct;

        acct = nf_conn_acct_find(ct);
        if (!acct)
                return 0;

        nest_count = nla_nest_start(skb, type | NLA_F_NESTED);
        if (!nest_count)
                goto nla_put_failure;

        NLA_PUT_BE64(skb, CTA_COUNTERS_PACKETS,
                     cpu_to_be64(acct[dir].packets));
        NLA_PUT_BE64(skb, CTA_COUNTERS_BYTES,
                     cpu_to_be64(acct[dir].bytes));

        nla_nest_end(skb, nest_count);

        return 0;

nla_put_failure:
        return -1;
}

#ifdef CONFIG_NF_CONNTRACK_MARK
static inline int
ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
{
        NLA_PUT_BE32(skb, CTA_MARK, htonl(ct->mark));
        return 0;

nla_put_failure:
        return -1;
}
#else
#define ctnetlink_dump_mark(a, b) (0)
#endif

#ifdef CONFIG_NF_CONNTRACK_SECMARK
static inline int
ctnetlink_dump_secmark(struct sk_buff *skb, const struct nf_conn *ct)
{
        NLA_PUT_BE32(skb, CTA_SECMARK, htonl(ct->secmark));
        return 0;

nla_put_failure:
        return -1;
}
#else
#define ctnetlink_dump_secmark(a, b) (0)
#endif

#define master_tuple(ct) &(ct->master->tuplehash[IP_CT_DIR_ORIGINAL].tuple)

static inline int
ctnetlink_dump_master(struct sk_buff *skb, const struct nf_conn *ct)
{
        struct nlattr *nest_parms;

        if (!(ct->status & IPS_EXPECTED))
                return 0;

        nest_parms = nla_nest_start(skb, CTA_TUPLE_MASTER | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;
        if (ctnetlink_dump_tuples(skb, master_tuple(ct)) < 0)
                goto nla_put_failure;
        nla_nest_end(skb, nest_parms);

        return 0;

nla_put_failure:
        return -1;
}

#ifdef CONFIG_NF_NAT_NEEDED
static int
dump_nat_seq_adj(struct sk_buff *skb, const struct nf_nat_seq *natseq, int type)
{
        struct nlattr *nest_parms;

        nest_parms = nla_nest_start(skb, type | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;

        NLA_PUT_BE32(skb, CTA_NAT_SEQ_CORRECTION_POS,
                     htonl(natseq->correction_pos));
        NLA_PUT_BE32(skb, CTA_NAT_SEQ_OFFSET_BEFORE,
                     htonl(natseq->offset_before));
        NLA_PUT_BE32(skb, CTA_NAT_SEQ_OFFSET_AFTER,
                     htonl(natseq->offset_after));

        nla_nest_end(skb, nest_parms);

        return 0;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_dump_nat_seq_adj(struct sk_buff *skb, const struct nf_conn *ct)
{
        struct nf_nat_seq *natseq;
        struct nf_conn_nat *nat = nfct_nat(ct);

        if (!(ct->status & IPS_SEQ_ADJUST) || !nat)
                return 0;

        natseq = &nat->seq[IP_CT_DIR_ORIGINAL];
        if (dump_nat_seq_adj(skb, natseq, CTA_NAT_SEQ_ADJ_ORIG) == -1)
                return -1;

        natseq = &nat->seq[IP_CT_DIR_REPLY];
        if (dump_nat_seq_adj(skb, natseq, CTA_NAT_SEQ_ADJ_REPLY) == -1)
                return -1;

        return 0;
}
#else
#define ctnetlink_dump_nat_seq_adj(a, b) (0)
#endif

static inline int
ctnetlink_dump_id(struct sk_buff *skb, const struct nf_conn *ct)
{
        NLA_PUT_BE32(skb, CTA_ID, htonl((unsigned long)ct));
        return 0;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_dump_use(struct sk_buff *skb, const struct nf_conn *ct)
{
        NLA_PUT_BE32(skb, CTA_USE, htonl(atomic_read(&ct->ct_general.use)));
        return 0;

nla_put_failure:
        return -1;
}

#define tuple(ct, dir) (&(ct)->tuplehash[dir].tuple)

static int
ctnetlink_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
                    int event, int nowait,
                    const struct nf_conn *ct)
{
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfmsg;
        struct nlattr *nest_parms;
        unsigned char *b = skb_tail_pointer(skb);

        event |= NFNL_SUBSYS_CTNETLINK << 8;
        nlh    = NLMSG_PUT(skb, pid, seq, event, sizeof(struct nfgenmsg));
        nfmsg  = NLMSG_DATA(nlh);

        nlh->nlmsg_flags    = (nowait && pid) ? NLM_F_MULTI : 0;
        nfmsg->nfgen_family = nf_ct_l3num(ct);
        nfmsg->version      = NFNETLINK_V0;
        nfmsg->res_id       = 0;

        nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;
        if (ctnetlink_dump_tuples(skb, tuple(ct, IP_CT_DIR_ORIGINAL)) < 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, tuple(ct, IP_CT_DIR_REPLY)) < 0)
                goto nla_put_failure;
        nla_nest_end(skb, nest_parms);

        if (ctnetlink_dump_status(skb, ct) < 0 ||
            ctnetlink_dump_timeout(skb, ct) < 0 ||
            ctnetlink_dump_counters(skb, ct, IP_CT_DIR_ORIGINAL) < 0 ||
            ctnetlink_dump_counters(skb, ct, IP_CT_DIR_REPLY) < 0 ||
            ctnetlink_dump_protoinfo(skb, ct) < 0 ||
            ctnetlink_dump_helpinfo(skb, ct) < 0 ||
            ctnetlink_dump_mark(skb, ct) < 0 ||
            ctnetlink_dump_secmark(skb, ct) < 0 ||
            ctnetlink_dump_id(skb, ct) < 0 ||
            ctnetlink_dump_use(skb, ct) < 0 ||
            ctnetlink_dump_master(skb, ct) < 0 ||
            ctnetlink_dump_nat_seq_adj(skb, ct) < 0)
                goto nla_put_failure;

        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
        return skb->len;

nlmsg_failure:
nla_put_failure:
        nlmsg_trim(skb, b);
        return -1;
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS
static int ctnetlink_conntrack_event(struct notifier_block *this,
                                     unsigned long events, void *ptr)
{
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfmsg;
        struct nlattr *nest_parms;
        struct nf_conn *ct = (struct nf_conn *)ptr;
        struct sk_buff *skb;
        unsigned int type;
        sk_buff_data_t b;
        unsigned int flags = 0, group;

        /* ignore our fake conntrack entry */
        if (ct == &nf_conntrack_untracked)
                return NOTIFY_DONE;

        if (events & IPCT_DESTROY) {
                type = IPCTNL_MSG_CT_DELETE;
                group = NFNLGRP_CONNTRACK_DESTROY;
        } else  if (events & (IPCT_NEW | IPCT_RELATED)) {
                type = IPCTNL_MSG_CT_NEW;
                flags = NLM_F_CREATE|NLM_F_EXCL;
                group = NFNLGRP_CONNTRACK_NEW;
        } else  if (events & (IPCT_STATUS | IPCT_PROTOINFO)) {
                type = IPCTNL_MSG_CT_NEW;
                group = NFNLGRP_CONNTRACK_UPDATE;
        } else
                return NOTIFY_DONE;

        if (!nfnetlink_has_listeners(group))
                return NOTIFY_DONE;

        skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
        if (!skb)
                return NOTIFY_DONE;

        b = skb->tail;

        type |= NFNL_SUBSYS_CTNETLINK << 8;
        nlh   = NLMSG_PUT(skb, 0, 0, type, sizeof(struct nfgenmsg));
        nfmsg = NLMSG_DATA(nlh);

        nlh->nlmsg_flags    = flags;
        nfmsg->nfgen_family = nf_ct_l3num(ct);
        nfmsg->version  = NFNETLINK_V0;
        nfmsg->res_id   = 0;

        nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;
        if (ctnetlink_dump_tuples(skb, tuple(ct, IP_CT_DIR_ORIGINAL)) < 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, tuple(ct, IP_CT_DIR_REPLY)) < 0)
                goto nla_put_failure;
        nla_nest_end(skb, nest_parms);

        if (ctnetlink_dump_id(skb, ct) < 0)
                goto nla_put_failure;

        if (ctnetlink_dump_status(skb, ct) < 0)
                goto nla_put_failure;

        if (events & IPCT_DESTROY) {
                if (ctnetlink_dump_counters(skb, ct, IP_CT_DIR_ORIGINAL) < 0 ||
                    ctnetlink_dump_counters(skb, ct, IP_CT_DIR_REPLY) < 0)
                        goto nla_put_failure;
        } else {
                if (ctnetlink_dump_timeout(skb, ct) < 0)
                        goto nla_put_failure;

                if (events & IPCT_PROTOINFO
                    && ctnetlink_dump_protoinfo(skb, ct) < 0)
                        goto nla_put_failure;

                if ((events & IPCT_HELPER || nfct_help(ct))
                    && ctnetlink_dump_helpinfo(skb, ct) < 0)
                        goto nla_put_failure;

#ifdef CONFIG_NF_CONNTRACK_SECMARK
                if ((events & IPCT_SECMARK || ct->secmark)
                    && ctnetlink_dump_secmark(skb, ct) < 0)
                        goto nla_put_failure;
#endif

                if (events & IPCT_RELATED &&
                    ctnetlink_dump_master(skb, ct) < 0)
                        goto nla_put_failure;

                if (events & IPCT_NATSEQADJ &&
                    ctnetlink_dump_nat_seq_adj(skb, ct) < 0)
                        goto nla_put_failure;
        }

#ifdef CONFIG_NF_CONNTRACK_MARK
        if ((events & IPCT_MARK || ct->mark)
            && ctnetlink_dump_mark(skb, ct) < 0)
                goto nla_put_failure;
#endif

        nlh->nlmsg_len = skb->tail - b;
        nfnetlink_send(skb, 0, group, 0);
        return NOTIFY_DONE;

nlmsg_failure:
nla_put_failure:
        kfree_skb(skb);
        return NOTIFY_DONE;
}
#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]);
        return 0;
}

static int
ctnetlink_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct nf_conn *ct, *last;
        struct nf_conntrack_tuple_hash *h;
        struct hlist_node *n;
        struct nfgenmsg *nfmsg = NLMSG_DATA(cb->nlh);
        u_int8_t l3proto = nfmsg->nfgen_family;

        rcu_read_lock();
        last = (struct nf_conn *)cb->args[1];
        for (; cb->args[0] < nf_conntrack_htable_size; cb->args[0]++) {
restart:
                hlist_for_each_entry_rcu(h, n, &init_net.ct.hash[cb->args[0]],
                                         hnode) {
                        if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
                                continue;
                        ct = nf_ct_tuplehash_to_ctrack(h);
                        /* Dump entries of a given L3 protocol number.
                         * If it is not specified, ie. l3proto == 0,
                         * then dump everything. */
                        if (l3proto && nf_ct_l3num(ct) != l3proto)
                                continue;
                        if (cb->args[1]) {
                                if (ct != last)
                                        continue;
                                cb->args[1] = 0;
                        }
                        if (ctnetlink_fill_info(skb, NETLINK_CB(cb->skb).pid,
                                                cb->nlh->nlmsg_seq,
                                                IPCTNL_MSG_CT_NEW,
                                                1, ct) < 0) {
                                if (!atomic_inc_not_zero(&ct->ct_general.use))
                                        continue;
                                cb->args[1] = (unsigned long)ct;
                                goto out;
                        }

                        if (NFNL_MSG_TYPE(cb->nlh->nlmsg_type) ==
                                                IPCTNL_MSG_CT_GET_CTRZERO) {
                                struct nf_conn_counter *acct;

                                acct = nf_conn_acct_find(ct);
                                if (acct)
                                        memset(acct, 0, sizeof(struct nf_conn_counter[IP_CT_DIR_MAX]));
                        }
                }
                if (cb->args[1]) {
                        cb->args[1] = 0;
                        goto restart;
                }
        }
out:
        rcu_read_unlock();
        if (last)
                nf_ct_put(last);

        return skb->len;
}

static inline int
ctnetlink_parse_tuple_ip(struct nlattr *attr, struct nf_conntrack_tuple *tuple)
{
        struct nlattr *tb[CTA_IP_MAX+1];
        struct nf_conntrack_l3proto *l3proto;
        int ret = 0;

        nla_parse_nested(tb, CTA_IP_MAX, attr, NULL);

        l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);

        if (likely(l3proto->nlattr_to_tuple)) {
                ret = nla_validate_nested(attr, CTA_IP_MAX,
                                          l3proto->nla_policy);
                if (ret == 0)
                        ret = l3proto->nlattr_to_tuple(tb, tuple);
        }

        nf_ct_l3proto_put(l3proto);

        return ret;
}

static const struct nla_policy proto_nla_policy[CTA_PROTO_MAX+1] = {
        [CTA_PROTO_NUM] = { .type = NLA_U8 },
};

static inline int
ctnetlink_parse_tuple_proto(struct nlattr *attr,
                            struct nf_conntrack_tuple *tuple)
{
        struct nlattr *tb[CTA_PROTO_MAX+1];
        struct nf_conntrack_l4proto *l4proto;
        int ret = 0;

        ret = nla_parse_nested(tb, CTA_PROTO_MAX, attr, proto_nla_policy);
        if (ret < 0)
                return ret;

        if (!tb[CTA_PROTO_NUM])
                return -EINVAL;
        tuple->dst.protonum = nla_get_u8(tb[CTA_PROTO_NUM]);

        l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);

        if (likely(l4proto->nlattr_to_tuple)) {
                ret = nla_validate_nested(attr, CTA_PROTO_MAX,
                                          l4proto->nla_policy);
                if (ret == 0)
                        ret = l4proto->nlattr_to_tuple(tb, tuple);
        }

        nf_ct_l4proto_put(l4proto);

        return ret;
}

static int
ctnetlink_parse_tuple(struct nlattr *cda[], struct nf_conntrack_tuple *tuple,
                      enum ctattr_tuple type, u_int8_t l3num)
{
        struct nlattr *tb[CTA_TUPLE_MAX+1];
        int err;

        memset(tuple, 0, sizeof(*tuple));

        nla_parse_nested(tb, CTA_TUPLE_MAX, cda[type], NULL);

        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;

        /* 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;
}

#ifdef CONFIG_NF_NAT_NEEDED
static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
        [CTA_PROTONAT_PORT_MIN] = { .type = NLA_U16 },
        [CTA_PROTONAT_PORT_MAX] = { .type = NLA_U16 },
};

static int nfnetlink_parse_nat_proto(struct nlattr *attr,
                                     const struct nf_conn *ct,
                                     struct nf_nat_range *range)
{
        struct nlattr *tb[CTA_PROTONAT_MAX+1];
        const struct nf_nat_protocol *npt;
        int err;

        err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
        if (err < 0)
                return err;

        npt = nf_nat_proto_find_get(nf_ct_protonum(ct));
        if (npt->nlattr_to_range)
                err = npt->nlattr_to_range(tb, range);
        nf_nat_proto_put(npt);
        return err;
}

static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
        [CTA_NAT_MINIP]         = { .type = NLA_U32 },
        [CTA_NAT_MAXIP]         = { .type = NLA_U32 },
};

static inline int
nfnetlink_parse_nat(struct nlattr *nat,
                    const struct nf_conn *ct, struct nf_nat_range *range)
{
        struct nlattr *tb[CTA_NAT_MAX+1];
        int err;

        memset(range, 0, sizeof(*range));

        err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
        if (err < 0)
                return err;

        if (tb[CTA_NAT_MINIP])
                range->min_ip = nla_get_be32(tb[CTA_NAT_MINIP]);

        if (!tb[CTA_NAT_MAXIP])
                range->max_ip = range->min_ip;
        else
                range->max_ip = nla_get_be32(tb[CTA_NAT_MAXIP]);

        if (range->min_ip)
                range->flags |= IP_NAT_RANGE_MAP_IPS;

        if (!tb[CTA_NAT_PROTO])
                return 0;

        err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
        if (err < 0)
                return err;

        return 0;
}
#endif

static inline int
ctnetlink_parse_help(struct nlattr *attr, char **helper_name)
{
        struct nlattr *tb[CTA_HELP_MAX+1];

        nla_parse_nested(tb, CTA_HELP_MAX, attr, NULL);

        if (!tb[CTA_HELP_NAME])
                return -EINVAL;

        *helper_name = nla_data(tb[CTA_HELP_NAME]);

        return 0;
}

static const struct nla_policy ct_nla_policy[CTA_MAX+1] = {
        [CTA_STATUS]            = { .type = NLA_U32 },
        [CTA_TIMEOUT]           = { .type = NLA_U32 },
        [CTA_MARK]              = { .type = NLA_U32 },
        [CTA_USE]               = { .type = NLA_U32 },
        [CTA_ID]                = { .type = NLA_U32 },
};

static int
ctnetlink_del_conntrack(struct sock *ctnl, struct sk_buff *skb,
                        struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_tuple tuple;
        struct nf_conn *ct;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int8_t u3 = nfmsg->nfgen_family;
        int err = 0;

        if (cda[CTA_TUPLE_ORIG])
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_ORIG, u3);
        else if (cda[CTA_TUPLE_REPLY])
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_REPLY, u3);
        else {
                /* Flush the whole table */
                nf_conntrack_flush(&init_net);
                return 0;
        }

        if (err < 0)
                return err;

        h = nf_conntrack_find_get(&init_net, &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_kill(ct);
        nf_ct_put(ct);

        return 0;
}

static int
ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
                        struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_tuple tuple;
        struct nf_conn *ct;
        struct sk_buff *skb2 = NULL;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int8_t u3 = nfmsg->nfgen_family;
        int err = 0;

        if (nlh->nlmsg_flags & NLM_F_DUMP)
                return netlink_dump_start(ctnl, skb, nlh, ctnetlink_dump_table,
                                          ctnetlink_done);

        if (cda[CTA_TUPLE_ORIG])
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_ORIG, u3);
        else if (cda[CTA_TUPLE_REPLY])
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_TUPLE_REPLY, u3);
        else
                return -EINVAL;

        if (err < 0)
                return err;

        h = nf_conntrack_find_get(&init_net, &tuple);
        if (!h)
                return -ENOENT;

        ct = nf_ct_tuplehash_to_ctrack(h);

        err = -ENOMEM;
        skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb2) {
                nf_ct_put(ct);
                return -ENOMEM;
        }

        err = ctnetlink_fill_info(skb2, NETLINK_CB(skb).pid, nlh->nlmsg_seq,
                                  IPCTNL_MSG_CT_NEW, 1, ct);
        nf_ct_put(ct);
        if (err <= 0)
                goto free;

        err = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid, MSG_DONTWAIT);
        if (err < 0)
                goto out;

        return 0;

free:
        kfree_skb(skb2);
out:
        return err;
}

static int
ctnetlink_change_status(struct nf_conn *ct, struct nlattr *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;

        if (cda[CTA_NAT_SRC] || cda[CTA_NAT_DST]) {
#ifndef CONFIG_NF_NAT_NEEDED
                return -EOPNOTSUPP;
#else
                struct nf_nat_range range;

                if (cda[CTA_NAT_DST]) {
                        if (nfnetlink_parse_nat(cda[CTA_NAT_DST], ct,
                                                &range) < 0)
                                return -EINVAL;
                        if (nf_nat_initialized(ct, IP_NAT_MANIP_DST))
                                return -EEXIST;
                        nf_nat_setup_info(ct, &range, IP_NAT_MANIP_DST);
                }
                if (cda[CTA_NAT_SRC]) {
                        if (nfnetlink_parse_nat(cda[CTA_NAT_SRC], ct,
                                                &range) < 0)
                                return -EINVAL;
                        if (nf_nat_initialized(ct, IP_NAT_MANIP_SRC))
                                return -EEXIST;
                        nf_nat_setup_info(ct, &range, IP_NAT_MANIP_SRC);
                }
#endif
        }

        /* Be careful here, modifying NAT bits can screw up things,
         * so don't let users modify them directly if they don't pass
         * nf_nat_range. */
        ct->status |= status & ~(IPS_NAT_DONE_MASK | IPS_NAT_MASK);
        return 0;
}


static inline int
ctnetlink_change_helper(struct nf_conn *ct, struct nlattr *cda[])
{
        struct nf_conntrack_helper *helper;
        struct nf_conn_help *help = nfct_help(ct);
        char *helpname;
        int err;

        /* don't change helper of sibling connections */
        if (ct->master)
                return -EBUSY;

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

        if (!strcmp(helpname, "")) {
                if (help && help->helper) {
                        /* we had a helper before ... */
                        nf_ct_remove_expectations(ct);
                        rcu_assign_pointer(help->helper, NULL);
                }

                return 0;
        }

        helper = __nf_conntrack_helper_find_byname(helpname);
        if (helper == NULL)
                return -EOPNOTSUPP;

        if (help) {
                if (help->helper == helper)
                        return 0;
                if (help->helper)
                        return -EBUSY;
                /* need to zero data of old helper */
                memset(&help->help, 0, sizeof(help->help));
        } else {
                help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
                if (help == NULL)
                        return -ENOMEM;
        }

        rcu_assign_pointer(help->helper, helper);

        return 0;
}

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

        if (!del_timer(&ct->timeout))
                return -ETIME;

        ct->timeout.expires = jiffies + timeout * HZ;
        add_timer(&ct->timeout);

        return 0;
}

static inline int
ctnetlink_change_protoinfo(struct nf_conn *ct, struct nlattr *cda[])
{
        struct nlattr *tb[CTA_PROTOINFO_MAX+1], *attr = cda[CTA_PROTOINFO];
        struct nf_conntrack_l4proto *l4proto;
        int err = 0;

        nla_parse_nested(tb, CTA_PROTOINFO_MAX, attr, NULL);

        l4proto = nf_ct_l4proto_find_get(nf_ct_l3num(ct), nf_ct_protonum(ct));
        if (l4proto->from_nlattr)
                err = l4proto->from_nlattr(tb, ct);
        nf_ct_l4proto_put(l4proto);

        return err;
}

#ifdef CONFIG_NF_NAT_NEEDED
static inline int
change_nat_seq_adj(struct nf_nat_seq *natseq, struct nlattr *attr)
{
        struct nlattr *cda[CTA_NAT_SEQ_MAX+1];

        nla_parse_nested(cda, CTA_NAT_SEQ_MAX, attr, NULL);

        if (!cda[CTA_NAT_SEQ_CORRECTION_POS])
                return -EINVAL;

        natseq->correction_pos =
                ntohl(nla_get_be32(cda[CTA_NAT_SEQ_CORRECTION_POS]));

        if (!cda[CTA_NAT_SEQ_OFFSET_BEFORE])
                return -EINVAL;

        natseq->offset_before =
                ntohl(nla_get_be32(cda[CTA_NAT_SEQ_OFFSET_BEFORE]));

        if (!cda[CTA_NAT_SEQ_OFFSET_AFTER])
                return -EINVAL;

        natseq->offset_after =
                ntohl(nla_get_be32(cda[CTA_NAT_SEQ_OFFSET_AFTER]));

        return 0;
}

static int
ctnetlink_change_nat_seq_adj(struct nf_conn *ct, struct nlattr *cda[])
{
        int ret = 0;
        struct nf_conn_nat *nat = nfct_nat(ct);

        if (!nat)
                return 0;

        if (cda[CTA_NAT_SEQ_ADJ_ORIG]) {
                ret = change_nat_seq_adj(&nat->seq[IP_CT_DIR_ORIGINAL],
                                         cda[CTA_NAT_SEQ_ADJ_ORIG]);
                if (ret < 0)
                        return ret;

                ct->status |= IPS_SEQ_ADJUST;
        }

        if (cda[CTA_NAT_SEQ_ADJ_REPLY]) {
                ret = change_nat_seq_adj(&nat->seq[IP_CT_DIR_REPLY],
                                         cda[CTA_NAT_SEQ_ADJ_REPLY]);
                if (ret < 0)
                        return ret;

                ct->status |= IPS_SEQ_ADJUST;
        }

        return 0;
}
#endif

static int
ctnetlink_change_conntrack(struct nf_conn *ct, struct nlattr *cda[])
{
        int err;

        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

#ifdef CONFIG_NF_NAT_NEEDED
        if (cda[CTA_NAT_SEQ_ADJ_ORIG] || cda[CTA_NAT_SEQ_ADJ_REPLY]) {
                err = ctnetlink_change_nat_seq_adj(ct, cda);
                if (err < 0)
                        return err;
        }
#endif

        return 0;
}

static int
ctnetlink_create_conntrack(struct nlattr *cda[],
                           struct nf_conntrack_tuple *otuple,
                           struct nf_conntrack_tuple *rtuple,
                           struct nf_conn *master_ct)
{
        struct nf_conn *ct;
        int err = -EINVAL;
        struct nf_conn_help *help;
        struct nf_conntrack_helper *helper;

        ct = nf_conntrack_alloc(&init_net, otuple, rtuple, GFP_KERNEL);
        if (ct == NULL || IS_ERR(ct))
                return -ENOMEM;

        if (!cda[CTA_TIMEOUT])
                goto err;
        ct->timeout.expires = ntohl(nla_get_be32(cda[CTA_TIMEOUT]));

        ct->timeout.expires = jiffies + ct->timeout.expires * HZ;
        ct->status |= IPS_CONFIRMED;

        rcu_read_lock();
        helper = __nf_ct_helper_find(rtuple);
        if (helper) {
                help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
                if (help == NULL) {
                        rcu_read_unlock();
                        err = -ENOMEM;
                        goto err;
                }
                /* not in hash table yet so not strictly necessary */
                rcu_assign_pointer(help->helper, helper);
        }

        if (cda[CTA_STATUS]) {
                err = ctnetlink_change_status(ct, cda);
                if (err < 0) {
                        rcu_read_unlock();
                        goto err;
                }
        }

        if (cda[CTA_PROTOINFO]) {
                err = ctnetlink_change_protoinfo(ct, cda);
                if (err < 0) {
                        rcu_read_unlock();
                        goto err;
                }
        }

        nf_ct_acct_ext_add(ct, GFP_KERNEL);

#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 (master_ct) {
                __set_bit(IPS_EXPECTED_BIT, &ct->status);
                ct->master = master_ct;
        }

        add_timer(&ct->timeout);
        nf_conntrack_hash_insert(ct);
        rcu_read_unlock();

        return 0;

err:
        nf_conntrack_free(ct);
        return err;
}

static int
ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
                        struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_tuple otuple, rtuple;
        struct nf_conntrack_tuple_hash *h = NULL;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int8_t u3 = nfmsg->nfgen_family;
        int err = 0;

        if (cda[CTA_TUPLE_ORIG]) {
                err = ctnetlink_parse_tuple(cda, &otuple, CTA_TUPLE_ORIG, u3);
                if (err < 0)
                        return err;
        }

        if (cda[CTA_TUPLE_REPLY]) {
                err = ctnetlink_parse_tuple(cda, &rtuple, CTA_TUPLE_REPLY, u3);
                if (err < 0)
                        return err;
        }

        spin_lock_bh(&nf_conntrack_lock);
        if (cda[CTA_TUPLE_ORIG])
                h = __nf_conntrack_find(&init_net, &otuple);
        else if (cda[CTA_TUPLE_REPLY])
                h = __nf_conntrack_find(&init_net, &rtuple);

        if (h == NULL) {
                struct nf_conntrack_tuple master;
                struct nf_conntrack_tuple_hash *master_h = NULL;
                struct nf_conn *master_ct = NULL;

                if (cda[CTA_TUPLE_MASTER]) {
                        err = ctnetlink_parse_tuple(cda,
                                                    &master,
                                                    CTA_TUPLE_MASTER,
                                                    u3);
                        if (err < 0)
                                goto out_unlock;

                        master_h = __nf_conntrack_find(&init_net, &master);
                        if (master_h == NULL) {
                                err = -ENOENT;
                                goto out_unlock;
                        }
                        master_ct = nf_ct_tuplehash_to_ctrack(master_h);
                        atomic_inc(&master_ct->ct_general.use);
                }

                spin_unlock_bh(&nf_conntrack_lock);
                err = -ENOENT;
                if (nlh->nlmsg_flags & NLM_F_CREATE)
                        err = ctnetlink_create_conntrack(cda,
                                                         &otuple,
                                                         &rtuple,
                                                         master_ct);
                if (err < 0 && master_ct)
                        nf_ct_put(master_ct);

                return err;
        }
        /* implicit 'else' */

        /* We manipulate the conntrack inside the global conntrack table lock,
         * so there's no need to increase the refcount */
        err = -EEXIST;
        if (!(nlh->nlmsg_flags & NLM_F_EXCL)) {
                /* we only allow nat config for new conntracks */
                if (cda[CTA_NAT_SRC] || cda[CTA_NAT_DST]) {
                        err = -EOPNOTSUPP;
                        goto out_unlock;
                }
                /* can't link an existing conntrack to a master */
                if (cda[CTA_TUPLE_MASTER]) {
                        err = -EOPNOTSUPP;
                        goto out_unlock;
                }
                err = ctnetlink_change_conntrack(nf_ct_tuplehash_to_ctrack(h),
                                                 cda);
        }

out_unlock:
        spin_unlock_bh(&nf_conntrack_lock);
        return err;
}

/***********************************************************************
 * EXPECT
 ***********************************************************************/

static inline int
ctnetlink_exp_dump_tuple(struct sk_buff *skb,
                         const struct nf_conntrack_tuple *tuple,
                         enum ctattr_expect type)
{
        struct nlattr *nest_parms;

        nest_parms = nla_nest_start(skb, type | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;
        if (ctnetlink_dump_tuples(skb, tuple) < 0)
                goto nla_put_failure;
        nla_nest_end(skb, nest_parms);

        return 0;

nla_put_failure:
        return -1;
}

static inline int
ctnetlink_exp_dump_mask(struct sk_buff *skb,
                        const struct nf_conntrack_tuple *tuple,
                        const struct nf_conntrack_tuple_mask *mask)
{
        int ret;
        struct nf_conntrack_l3proto *l3proto;
        struct nf_conntrack_l4proto *l4proto;
        struct nf_conntrack_tuple m;
        struct nlattr *nest_parms;

        memset(&m, 0xFF, sizeof(m));
        m.src.u.all = mask->src.u.all;
        memcpy(&m.src.u3, &mask->src.u3, sizeof(m.src.u3));

        nest_parms = nla_nest_start(skb, CTA_EXPECT_MASK | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;

        l3proto = nf_ct_l3proto_find_get(tuple->src.l3num);
        ret = ctnetlink_dump_tuples_ip(skb, &m, l3proto);
        nf_ct_l3proto_put(l3proto);

        if (unlikely(ret < 0))
                goto nla_put_failure;

        l4proto = nf_ct_l4proto_find_get(tuple->src.l3num, tuple->dst.protonum);
        ret = ctnetlink_dump_tuples_proto(skb, &m, l4proto);
        nf_ct_l4proto_put(l4proto);
        if (unlikely(ret < 0))
                goto nla_put_failure;

        nla_nest_end(skb, nest_parms);

        return 0;

nla_put_failure:
        return -1;
}

static int
ctnetlink_exp_dump_expect(struct sk_buff *skb,
                          const struct nf_conntrack_expect *exp)
{
        struct nf_conn *master = exp->master;
        long timeout = (exp->timeout.expires - jiffies) / HZ;

        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;

        NLA_PUT_BE32(skb, CTA_EXPECT_TIMEOUT, htonl(timeout));
        NLA_PUT_BE32(skb, CTA_EXPECT_ID, htonl((unsigned long)exp));

        return 0;

nla_put_failure:
        return -1;
}

static int
ctnetlink_exp_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
                    int event,
                    int nowait,
                    const struct nf_conntrack_expect *exp)
{
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfmsg;
        unsigned char *b = skb_tail_pointer(skb);

        event |= NFNL_SUBSYS_CTNETLINK_EXP << 8;
        nlh    = NLMSG_PUT(skb, pid, seq, event, sizeof(struct nfgenmsg));
        nfmsg  = NLMSG_DATA(nlh);

        nlh->nlmsg_flags    = (nowait && pid) ? NLM_F_MULTI : 0;
        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;

        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
        return skb->len;

nlmsg_failure:
nla_put_failure:
        nlmsg_trim(skb, b);
        return -1;
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS
static int ctnetlink_expect_event(struct notifier_block *this,
                                  unsigned long events, void *ptr)
{
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfmsg;
        struct nf_conntrack_expect *exp = (struct nf_conntrack_expect *)ptr;
        struct sk_buff *skb;
        unsigned int type;
        sk_buff_data_t b;
        int flags = 0;

        if (events & IPEXP_NEW) {
                type = IPCTNL_MSG_EXP_NEW;
                flags = NLM_F_CREATE|NLM_F_EXCL;
        } else
                return NOTIFY_DONE;

        if (!nfnetlink_has_listeners(NFNLGRP_CONNTRACK_EXP_NEW))
                return NOTIFY_DONE;

        skb = alloc_skb(NLMSG_GOODSIZE, GFP_ATOMIC);
        if (!skb)
                return NOTIFY_DONE;

        b = skb->tail;

        type |= NFNL_SUBSYS_CTNETLINK_EXP << 8;
        nlh   = NLMSG_PUT(skb, 0, 0, type, sizeof(struct nfgenmsg));
        nfmsg = NLMSG_DATA(nlh);

        nlh->nlmsg_flags    = flags;
        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;

        nlh->nlmsg_len = skb->tail - b;
        nfnetlink_send(skb, 0, NFNLGRP_CONNTRACK_EXP_NEW, 0);
        return NOTIFY_DONE;

nlmsg_failure:
nla_put_failure:
        kfree_skb(skb);
        return NOTIFY_DONE;
}
#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 = &init_net;
        struct nf_conntrack_expect *exp, *last;
        struct nfgenmsg *nfmsg = NLMSG_DATA(cb->nlh);
        struct hlist_node *n;
        u_int8_t l3proto = nfmsg->nfgen_family;

        rcu_read_lock();
        last = (struct nf_conntrack_expect *)cb->args[1];
        for (; cb->args[0] < nf_ct_expect_hsize; cb->args[0]++) {
restart:
                hlist_for_each_entry(exp, n, &net->ct.expect_hash[cb->args[0]],
                                     hnode) {
                        if (l3proto && exp->tuple.src.l3num != l3proto)
                                continue;
                        if (cb->args[1]) {
                                if (exp != last)
                                        continue;
                                cb->args[1] = 0;
                        }
                        if (ctnetlink_exp_fill_info(skb, NETLINK_CB(cb->skb).pid,
                                                    cb->nlh->nlmsg_seq,
                                                    IPCTNL_MSG_EXP_NEW,
                                                    1, exp) < 0) {
                                if (!atomic_inc_not_zero(&exp->use))
                                        continue;
                                cb->args[1] = (unsigned long)exp;
                                goto out;
                        }
                }
                if (cb->args[1]) {
                        cb->args[1] = 0;
                        goto restart;
                }
        }
out:
        rcu_read_unlock();
        if (last)
                nf_ct_expect_put(last);

        return skb->len;
}

static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = {
        [CTA_EXPECT_TIMEOUT]    = { .type = NLA_U32 },
        [CTA_EXPECT_ID]         = { .type = NLA_U32 },
};

static int
ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb,
                     struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_tuple tuple;
        struct nf_conntrack_expect *exp;
        struct sk_buff *skb2;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int8_t u3 = nfmsg->nfgen_family;
        int err = 0;

        if (nlh->nlmsg_flags & NLM_F_DUMP) {
                return netlink_dump_start(ctnl, skb, nlh,
                                          ctnetlink_exp_dump_table,
                                          ctnetlink_exp_done);
        }

        if (cda[CTA_EXPECT_MASTER])
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_MASTER, u3);
        else
                return -EINVAL;

        if (err < 0)
                return err;

        exp = nf_ct_expect_find_get(&init_net, &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 = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb2)
                goto out;

        err = ctnetlink_exp_fill_info(skb2, NETLINK_CB(skb).pid,
                                      nlh->nlmsg_seq, IPCTNL_MSG_EXP_NEW,
                                      1, exp);
        if (err <= 0)
                goto free;

        nf_ct_expect_put(exp);

        return netlink_unicast(ctnl, skb2, NETLINK_CB(skb).pid, MSG_DONTWAIT);

free:
        kfree_skb(skb2);
out:
        nf_ct_expect_put(exp);
        return err;
}

static int
ctnetlink_del_expect(struct sock *ctnl, struct sk_buff *skb,
                     struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_expect *exp;
        struct nf_conntrack_tuple tuple;
        struct nf_conntrack_helper *h;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        struct hlist_node *n, *next;
        u_int8_t u3 = nfmsg->nfgen_family;
        unsigned int i;
        int err;

        if (cda[CTA_EXPECT_TUPLE]) {
                /* delete a single expect by tuple */
                err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE, u3);
                if (err < 0)
                        return err;

                /* bump usage count to 2 */
                exp = nf_ct_expect_find_get(&init_net, &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 */
                nf_ct_unexpect_related(exp);
                /* 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_lock);
                h = __nf_conntrack_helper_find_byname(name);
                if (!h) {
                        spin_unlock_bh(&nf_conntrack_lock);
                        return -EOPNOTSUPP;
                }
                for (i = 0; i < nf_ct_expect_hsize; i++) {
                        hlist_for_each_entry_safe(exp, n, next,
                                                  &init_net.ct.expect_hash[i],
                                                  hnode) {
                                m_help = nfct_help(exp->master);
                                if (m_help->helper == h
                                    && del_timer(&exp->timeout)) {
                                        nf_ct_unlink_expect(exp);
                                        nf_ct_expect_put(exp);
                                }
                        }
                }
                spin_unlock_bh(&nf_conntrack_lock);
        } else {
                /* This basically means we have to flush everything*/
                spin_lock_bh(&nf_conntrack_lock);
                for (i = 0; i < nf_ct_expect_hsize; i++) {
                        hlist_for_each_entry_safe(exp, n, next,
                                                  &init_net.ct.expect_hash[i],
                                                  hnode) {
                                if (del_timer(&exp->timeout)) {
                                        nf_ct_unlink_expect(exp);
                                        nf_ct_expect_put(exp);
                                }
                        }
                }
                spin_unlock_bh(&nf_conntrack_lock);
        }

        return 0;
}
static int
ctnetlink_change_expect(struct nf_conntrack_expect *x, struct nlattr *cda[])
{
        return -EOPNOTSUPP;
}

static int
ctnetlink_create_expect(struct nlattr *cda[], u_int8_t u3)
{
        struct nf_conntrack_tuple tuple, mask, master_tuple;
        struct nf_conntrack_tuple_hash *h = NULL;
        struct nf_conntrack_expect *exp;
        struct nf_conn *ct;
        struct nf_conn_help *help;
        int err = 0;

        /* caller guarantees that those three CTA_EXPECT_* exist */
        err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE, u3);
        if (err < 0)
                return err;
        err = ctnetlink_parse_tuple(cda, &mask, CTA_EXPECT_MASK, u3);
        if (err < 0)
                return err;
        err = ctnetlink_parse_tuple(cda, &master_tuple, CTA_EXPECT_MASTER, u3);
        if (err < 0)
                return err;

        /* Look for master conntrack of this expectation */
        h = nf_conntrack_find_get(&init_net, &master_tuple);
        if (!h)
                return -ENOENT;
        ct = nf_ct_tuplehash_to_ctrack(h);
        help = nfct_help(ct);

        if (!help || !help->helper) {
                /* such conntrack hasn't got any helper, abort */
                err = -EINVAL;
                goto out;
        }

        exp = nf_ct_expect_alloc(ct);
        if (!exp) {
                err = -ENOMEM;
                goto out;
        }

        exp->expectfn = NULL;
        exp->flags = 0;
        exp->master = ct;
        exp->helper = NULL;
        memcpy(&exp->tuple, &tuple, sizeof(struct nf_conntrack_tuple));
        memcpy(&exp->mask.src.u3, &mask.src.u3, sizeof(exp->mask.src.u3));
        exp->mask.src.u.all = mask.src.u.all;

        err = nf_ct_expect_related(exp);
        nf_ct_expect_put(exp);

out:
        nf_ct_put(nf_ct_tuplehash_to_ctrack(h));
        return err;
}

static int
ctnetlink_new_expect(struct sock *ctnl, struct sk_buff *skb,
                     struct nlmsghdr *nlh, struct nlattr *cda[])
{
        struct nf_conntrack_tuple tuple;
        struct nf_conntrack_expect *exp;
        struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
        u_int8_t u3 = nfmsg->nfgen_family;
        int err = 0;

        if (!cda[CTA_EXPECT_TUPLE]
            || !cda[CTA_EXPECT_MASK]
            || !cda[CTA_EXPECT_MASTER])
                return -EINVAL;

        err = ctnetlink_parse_tuple(cda, &tuple, CTA_EXPECT_TUPLE, u3);
        if (err < 0)
                return err;

        spin_lock_bh(&nf_conntrack_lock);
        exp = __nf_ct_expect_find(&init_net, &tuple);

        if (!exp) {
                spin_unlock_bh(&nf_conntrack_lock);
                err = -ENOENT;
                if (nlh->nlmsg_flags & NLM_F_CREATE)
                        err = ctnetlink_create_expect(cda, u3);
                return err;
        }

        err = -EEXIST;
        if (!(nlh->nlmsg_flags & NLM_F_EXCL))
                err = ctnetlink_change_expect(exp, cda);
        spin_unlock_bh(&nf_conntrack_lock);

        return err;
}

#ifdef CONFIG_NF_CONNTRACK_EVENTS
static struct notifier_block ctnl_notifier = {
        .notifier_call  = ctnetlink_conntrack_event,
};

static struct notifier_block ctnl_notifier_exp = {
        .notifier_call  = ctnetlink_expect_event,
};
#endif

static const struct nfnl_callback ctnl_cb[IPCTNL_MSG_MAX] = {
        [IPCTNL_MSG_CT_NEW]             = { .call = ctnetlink_new_conntrack,
                                            .attr_count = CTA_MAX,
                                            .policy = ct_nla_policy },
        [IPCTNL_MSG_CT_GET]             = { .call = ctnetlink_get_conntrack,
                                            .attr_count = CTA_MAX,
                                            .policy = ct_nla_policy },
        [IPCTNL_MSG_CT_DELETE]          = { .call = ctnetlink_del_conntrack,
                                            .attr_count = CTA_MAX,
                                            .policy = ct_nla_policy },
        [IPCTNL_MSG_CT_GET_CTRZERO]     = { .call = ctnetlink_get_conntrack,
                                            .attr_count = CTA_MAX,
                                            .policy = ct_nla_policy },
};

static const struct nfnl_callback ctnl_exp_cb[IPCTNL_MSG_EXP_MAX] = {
        [IPCTNL_MSG_EXP_GET]            = { .call = ctnetlink_get_expect,
                                            .attr_count = CTA_EXPECT_MAX,
                                            .policy = exp_nla_policy },
        [IPCTNL_MSG_EXP_NEW]            = { .call = ctnetlink_new_expect,
                                            .attr_count = CTA_EXPECT_MAX,
                                            .policy = exp_nla_policy },
        [IPCTNL_MSG_EXP_DELETE]         = { .call = ctnetlink_del_expect,
                                            .attr_count = CTA_EXPECT_MAX,
                                            .policy = exp_nla_policy },
};

static const struct nfnetlink_subsystem ctnl_subsys = {
        .name                           = "conntrack",
        .subsys_id                      = NFNL_SUBSYS_CTNETLINK,
        .cb_count                       = IPCTNL_MSG_MAX,
        .cb                             = ctnl_cb,
};

static const struct nfnetlink_subsystem ctnl_exp_subsys = {
        .name                           = "conntrack_expect",
        .subsys_id                      = NFNL_SUBSYS_CTNETLINK_EXP,
        .cb_count                       = IPCTNL_MSG_EXP_MAX,
        .cb                             = ctnl_exp_cb,
};

MODULE_ALIAS("ip_conntrack_netlink");
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK);
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_EXP);

static int __init ctnetlink_init(void)
{
        int ret;

        printk("ctnetlink v%s: registering with nfnetlink.\n", version);
        ret = nfnetlink_subsys_register(&ctnl_subsys);
        if (ret < 0) {
                printk("ctnetlink_init: cannot register with nfnetlink.\n");
                goto err_out;
        }

        ret = nfnetlink_subsys_register(&ctnl_exp_subsys);
        if (ret < 0) {
                printk("ctnetlink_init: cannot register exp with nfnetlink.\n");
                goto err_unreg_subsys;
        }

#ifdef CONFIG_NF_CONNTRACK_EVENTS
        ret = nf_conntrack_register_notifier(&ctnl_notifier);
        if (ret < 0) {
                printk("ctnetlink_init: cannot register notifier.\n");
                goto err_unreg_exp_subsys;
        }

        ret = nf_ct_expect_register_notifier(&ctnl_notifier_exp);
        if (ret < 0) {
                printk("ctnetlink_init: cannot expect register notifier.\n");
                goto err_unreg_notifier;
        }
#endif

        return 0;

#ifdef CONFIG_NF_CONNTRACK_EVENTS
err_unreg_notifier:
        nf_conntrack_unregister_notifier(&ctnl_notifier);
err_unreg_exp_subsys:
        nfnetlink_subsys_unregister(&ctnl_exp_subsys);
#endif
err_unreg_subsys:
        nfnetlink_subsys_unregister(&ctnl_subsys);
err_out:
        return ret;
}

static void __exit ctnetlink_exit(void)
{
        printk("ctnetlink: unregistering from nfnetlink.\n");

#ifdef CONFIG_NF_CONNTRACK_EVENTS
        nf_ct_expect_unregister_notifier(&ctnl_notifier_exp);
        nf_conntrack_unregister_notifier(&ctnl_notifier);
#endif

        nfnetlink_subsys_unregister(&ctnl_exp_subsys);
        nfnetlink_subsys_unregister(&ctnl_subsys);
        return;
}

module_init(ctnetlink_init);
module_exit(ctnetlink_exit);

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