/*
 * Connection tracking protocol helper module for SCTP.
 *
 * Copyright (c) 2004 Kiran Kumar Immidi <immidi_kiran@yahoo.com>
 * Copyright (c) 2004-2012 Patrick McHardy <kaber@trash.net>
 *
 * SCTP is defined in RFC 2960. References to various sections in this code
 * are to this RFC.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/types.h>
#include <linux/timer.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/sctp.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_ecache.h>

/* FIXME: Examine ipfilter's timeouts and conntrack transitions more
   closely.  They're more complex. --RR

   And so for me for SCTP :D -Kiran */

static const char *const sctp_conntrack_names[] = {
        "NONE",
        "CLOSED",
        "COOKIE_WAIT",
        "COOKIE_ECHOED",
        "ESTABLISHED",
        "SHUTDOWN_SENT",
        "SHUTDOWN_RECD",
        "SHUTDOWN_ACK_SENT",
};

#define SECS  * HZ
#define MINS  * 60 SECS
#define HOURS * 60 MINS
#define DAYS  * 24 HOURS

static unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] __read_mostly = {
        [SCTP_CONNTRACK_CLOSED]                 = 10 SECS,
        [SCTP_CONNTRACK_COOKIE_WAIT]            = 3 SECS,
        [SCTP_CONNTRACK_COOKIE_ECHOED]          = 3 SECS,
        [SCTP_CONNTRACK_ESTABLISHED]            = 5 DAYS,
        [SCTP_CONNTRACK_SHUTDOWN_SENT]          = 300 SECS / 1000,
        [SCTP_CONNTRACK_SHUTDOWN_RECD]          = 300 SECS / 1000,
        [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT]      = 3 SECS,
};

#define sNO SCTP_CONNTRACK_NONE
#define sCL SCTP_CONNTRACK_CLOSED
#define sCW SCTP_CONNTRACK_COOKIE_WAIT
#define sCE SCTP_CONNTRACK_COOKIE_ECHOED
#define sES SCTP_CONNTRACK_ESTABLISHED
#define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
#define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
#define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
#define sIV SCTP_CONNTRACK_MAX

/*
        These are the descriptions of the states:

NOTE: These state names are tantalizingly similar to the states of an
SCTP endpoint. But the interpretation of the states is a little different,
considering that these are the states of the connection and not of an end
point. Please note the subtleties. -Kiran

NONE              - Nothing so far.
COOKIE WAIT       - We have seen an INIT chunk in the original direction, or also
                    an INIT_ACK chunk in the reply direction.
COOKIE ECHOED     - We have seen a COOKIE_ECHO chunk in the original direction.
ESTABLISHED       - We have seen a COOKIE_ACK in the reply direction.
SHUTDOWN_SENT     - We have seen a SHUTDOWN chunk in the original direction.
SHUTDOWN_RECD     - We have seen a SHUTDOWN chunk in the reply directoin.
SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
                    to that of the SHUTDOWN chunk.
CLOSED            - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
                    the SHUTDOWN chunk. Connection is closed.
*/

/* TODO
 - I have assumed that the first INIT is in the original direction.
 This messes things when an INIT comes in the reply direction in CLOSED
 state.
 - Check the error type in the reply dir before transitioning from
cookie echoed to closed.
 - Sec 5.2.4 of RFC 2960
 - Multi Homing support.
*/

/* SCTP conntrack state transitions */
static const u8 sctp_conntracks[2][9][SCTP_CONNTRACK_MAX] = {
        {
/*      ORIGINAL        */
/*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
/* init         */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA},
/* init_ack     */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},
/* abort        */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
/* shutdown     */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA},
/* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA},
/* error        */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Can't have Stale cookie*/
/* cookie_echo  */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA},/* 5.2.4 - Big TODO */
/* cookie_ack   */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Can't come in orig dir */
/* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL}
        },
        {
/*      REPLY   */
/*                  sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
/* init         */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* INIT in sCL Big TODO */
/* init_ack     */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},
/* abort        */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
/* shutdown     */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA},
/* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA},
/* error        */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA},
/* cookie_echo  */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Can't come in reply dir */
/* cookie_ack   */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA},
/* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL}
        }
};

static int sctp_net_id  __read_mostly;
struct sctp_net {
        struct nf_proto_net pn;
        unsigned int timeouts[SCTP_CONNTRACK_MAX];
};

static inline struct sctp_net *sctp_pernet(struct net *net)
{
        return net_generic(net, sctp_net_id);
}

static bool sctp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
                              struct nf_conntrack_tuple *tuple)
{
        const struct sctphdr *hp;
        struct sctphdr _hdr;

        /* Actually only need first 8 bytes. */
        hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
        if (hp == NULL)
                return false;

        tuple->src.u.sctp.port = hp->source;
        tuple->dst.u.sctp.port = hp->dest;
        return true;
}

static bool sctp_invert_tuple(struct nf_conntrack_tuple *tuple,
                              const struct nf_conntrack_tuple *orig)
{
        tuple->src.u.sctp.port = orig->dst.u.sctp.port;
        tuple->dst.u.sctp.port = orig->src.u.sctp.port;
        return true;
}

/* Print out the per-protocol part of the tuple. */
static int sctp_print_tuple(struct seq_file *s,
                            const struct nf_conntrack_tuple *tuple)
{
        return seq_printf(s, "sport=%hu dport=%hu ",
                          ntohs(tuple->src.u.sctp.port),
                          ntohs(tuple->dst.u.sctp.port));
}

/* Print out the private part of the conntrack. */
static int sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
{
        enum sctp_conntrack state;

        spin_lock_bh(&ct->lock);
        state = ct->proto.sctp.state;
        spin_unlock_bh(&ct->lock);

        return seq_printf(s, "%s ", sctp_conntrack_names[state]);
}

#define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)     \
for ((offset) = (dataoff) + sizeof(sctp_sctphdr_t), (count) = 0;        \
        (offset) < (skb)->len &&                                        \
        ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));   \
        (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)

/* Some validity checks to make sure the chunks are fine */
static int do_basic_checks(struct nf_conn *ct,
                           const struct sk_buff *skb,
                           unsigned int dataoff,
                           unsigned long *map)
{
        u_int32_t offset, count;
        sctp_chunkhdr_t _sch, *sch;
        int flag;

        flag = 0;

        for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
                pr_debug("Chunk Num: %d  Type: %d\n", count, sch->type);

                if (sch->type == SCTP_CID_INIT ||
                    sch->type == SCTP_CID_INIT_ACK ||
                    sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
                        flag = 1;

                /*
                 * Cookie Ack/Echo chunks not the first OR
                 * Init / Init Ack / Shutdown compl chunks not the only chunks
                 * OR zero-length.
                 */
                if (((sch->type == SCTP_CID_COOKIE_ACK ||
                      sch->type == SCTP_CID_COOKIE_ECHO ||
                      flag) &&
                     count != 0) || !sch->length) {
                        pr_debug("Basic checks failed\n");
                        return 1;
                }

                if (map)
                        set_bit(sch->type, map);
        }

        pr_debug("Basic checks passed\n");
        return count == 0;
}

static int sctp_new_state(enum ip_conntrack_dir dir,
                          enum sctp_conntrack cur_state,
                          int chunk_type)
{
        int i;

        pr_debug("Chunk type: %d\n", chunk_type);

        switch (chunk_type) {
        case SCTP_CID_INIT:
                pr_debug("SCTP_CID_INIT\n");
                i = 0;
                break;
        case SCTP_CID_INIT_ACK:
                pr_debug("SCTP_CID_INIT_ACK\n");
                i = 1;
                break;
        case SCTP_CID_ABORT:
                pr_debug("SCTP_CID_ABORT\n");
                i = 2;
                break;
        case SCTP_CID_SHUTDOWN:
                pr_debug("SCTP_CID_SHUTDOWN\n");
                i = 3;
                break;
        case SCTP_CID_SHUTDOWN_ACK:
                pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
                i = 4;
                break;
        case SCTP_CID_ERROR:
                pr_debug("SCTP_CID_ERROR\n");
                i = 5;
                break;
        case SCTP_CID_COOKIE_ECHO:
                pr_debug("SCTP_CID_COOKIE_ECHO\n");
                i = 6;
                break;
        case SCTP_CID_COOKIE_ACK:
                pr_debug("SCTP_CID_COOKIE_ACK\n");
                i = 7;
                break;
        case SCTP_CID_SHUTDOWN_COMPLETE:
                pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
                i = 8;
                break;
        default:
                /* Other chunks like DATA, SACK, HEARTBEAT and
                its ACK do not cause a change in state */
                pr_debug("Unknown chunk type, Will stay in %s\n",
                         sctp_conntrack_names[cur_state]);
                return cur_state;
        }

        pr_debug("dir: %d   cur_state: %s  chunk_type: %d  new_state: %s\n",
                 dir, sctp_conntrack_names[cur_state], chunk_type,
                 sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);

        return sctp_conntracks[dir][i][cur_state];
}

static unsigned int *sctp_get_timeouts(struct net *net)
{
        return sctp_pernet(net)->timeouts;
}

/* Returns verdict for packet, or -NF_ACCEPT for invalid. */
static int sctp_packet(struct nf_conn *ct,
                       const struct sk_buff *skb,
                       unsigned int dataoff,
                       enum ip_conntrack_info ctinfo,
                       u_int8_t pf,
                       unsigned int hooknum,
                       unsigned int *timeouts)
{
        enum sctp_conntrack new_state, old_state;
        enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
        const struct sctphdr *sh;
        struct sctphdr _sctph;
        const struct sctp_chunkhdr *sch;
        struct sctp_chunkhdr _sch;
        u_int32_t offset, count;
        unsigned long map[256 / sizeof(unsigned long)] = { 0 };

        sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
        if (sh == NULL)
                goto out;

        if (do_basic_checks(ct, skb, dataoff, map) != 0)
                goto out;

        /* Check the verification tag (Sec 8.5) */
        if (!test_bit(SCTP_CID_INIT, map) &&
            !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
            !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
            !test_bit(SCTP_CID_ABORT, map) &&
            !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
            sh->vtag != ct->proto.sctp.vtag[dir]) {
                pr_debug("Verification tag check failed\n");
                goto out;
        }

        old_state = new_state = SCTP_CONNTRACK_NONE;
        spin_lock_bh(&ct->lock);
        for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
                /* Special cases of Verification tag check (Sec 8.5.1) */
                if (sch->type == SCTP_CID_INIT) {
                        /* Sec 8.5.1 (A) */
                        if (sh->vtag != 0)
                                goto out_unlock;
                } else if (sch->type == SCTP_CID_ABORT) {
                        /* Sec 8.5.1 (B) */
                        if (sh->vtag != ct->proto.sctp.vtag[dir] &&
                            sh->vtag != ct->proto.sctp.vtag[!dir])
                                goto out_unlock;
                } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
                        /* Sec 8.5.1 (C) */
                        if (sh->vtag != ct->proto.sctp.vtag[dir] &&
                            sh->vtag != ct->proto.sctp.vtag[!dir] &&
                            sch->flags & SCTP_CHUNK_FLAG_T)
                                goto out_unlock;
                } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
                        /* Sec 8.5.1 (D) */
                        if (sh->vtag != ct->proto.sctp.vtag[dir])
                                goto out_unlock;
                }

                old_state = ct->proto.sctp.state;
                new_state = sctp_new_state(dir, old_state, sch->type);

                /* Invalid */
                if (new_state == SCTP_CONNTRACK_MAX) {
                        pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
                                 "conntrack=%u\n",
                                 dir, sch->type, old_state);
                        goto out_unlock;
                }

                /* If it is an INIT or an INIT ACK note down the vtag */
                if (sch->type == SCTP_CID_INIT ||
                    sch->type == SCTP_CID_INIT_ACK) {
                        sctp_inithdr_t _inithdr, *ih;

                        ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
                                                sizeof(_inithdr), &_inithdr);
                        if (ih == NULL)
                                goto out_unlock;
                        pr_debug("Setting vtag %x for dir %d\n",
                                 ih->init_tag, !dir);
                        ct->proto.sctp.vtag[!dir] = ih->init_tag;
                }

                ct->proto.sctp.state = new_state;
                if (old_state != new_state)
                        nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
        }
        spin_unlock_bh(&ct->lock);

        nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);

        if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
            dir == IP_CT_DIR_REPLY &&
            new_state == SCTP_CONNTRACK_ESTABLISHED) {
                pr_debug("Setting assured bit\n");
                set_bit(IPS_ASSURED_BIT, &ct->status);
                nf_conntrack_event_cache(IPCT_ASSURED, ct);
        }

        return NF_ACCEPT;

out_unlock:
        spin_unlock_bh(&ct->lock);
out:
        return -NF_ACCEPT;
}

/* Called when a new connection for this protocol found. */
static bool sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
                     unsigned int dataoff, unsigned int *timeouts)
{
        enum sctp_conntrack new_state;
        const struct sctphdr *sh;
        struct sctphdr _sctph;
        const struct sctp_chunkhdr *sch;
        struct sctp_chunkhdr _sch;
        u_int32_t offset, count;
        unsigned long map[256 / sizeof(unsigned long)] = { 0 };

        sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
        if (sh == NULL)
                return false;

        if (do_basic_checks(ct, skb, dataoff, map) != 0)
                return false;

        /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
        if (test_bit(SCTP_CID_ABORT, map) ||
            test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
            test_bit(SCTP_CID_COOKIE_ACK, map))
                return false;

        memset(&ct->proto.sctp, 0, sizeof(ct->proto.sctp));
        new_state = SCTP_CONNTRACK_MAX;
        for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
                /* Don't need lock here: this conntrack not in circulation yet */
                new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
                                           SCTP_CONNTRACK_NONE, sch->type);

                /* Invalid: delete conntrack */
                if (new_state == SCTP_CONNTRACK_NONE ||
                    new_state == SCTP_CONNTRACK_MAX) {
                        pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
                        return false;
                }

                /* Copy the vtag into the state info */
                if (sch->type == SCTP_CID_INIT) {
                        if (sh->vtag == 0) {
                                sctp_inithdr_t _inithdr, *ih;

                                ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
                                                        sizeof(_inithdr), &_inithdr);
                                if (ih == NULL)
                                        return false;

                                pr_debug("Setting vtag %x for new conn\n",
                                         ih->init_tag);

                                ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
                                                                ih->init_tag;
                        } else {
                                /* Sec 8.5.1 (A) */
                                return false;
                        }
                }
                /* If it is a shutdown ack OOTB packet, we expect a return
                   shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
                else {
                        pr_debug("Setting vtag %x for new conn OOTB\n",
                                 sh->vtag);
                        ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
                }

                ct->proto.sctp.state = new_state;
        }

        return true;
}

#if IS_ENABLED(CONFIG_NF_CT_NETLINK)

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

static int sctp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
                          struct nf_conn *ct)
{
        struct nlattr *nest_parms;

        spin_lock_bh(&ct->lock);
        nest_parms = nla_nest_start(skb, CTA_PROTOINFO_SCTP | NLA_F_NESTED);
        if (!nest_parms)
                goto nla_put_failure;

        if (nla_put_u8(skb, CTA_PROTOINFO_SCTP_STATE, ct->proto.sctp.state) ||
            nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_ORIGINAL,
                         ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL]) ||
            nla_put_be32(skb, CTA_PROTOINFO_SCTP_VTAG_REPLY,
                         ct->proto.sctp.vtag[IP_CT_DIR_REPLY]))
                goto nla_put_failure;

        spin_unlock_bh(&ct->lock);

        nla_nest_end(skb, nest_parms);

        return 0;

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

static const struct nla_policy sctp_nla_policy[CTA_PROTOINFO_SCTP_MAX+1] = {
        [CTA_PROTOINFO_SCTP_STATE]          = { .type = NLA_U8 },
        [CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]  = { .type = NLA_U32 },
        [CTA_PROTOINFO_SCTP_VTAG_REPLY]     = { .type = NLA_U32 },
};

static int nlattr_to_sctp(struct nlattr *cda[], struct nf_conn *ct)
{
        struct nlattr *attr = cda[CTA_PROTOINFO_SCTP];
        struct nlattr *tb[CTA_PROTOINFO_SCTP_MAX+1];
        int err;

        /* updates may not contain the internal protocol info, skip parsing */
        if (!attr)
                return 0;

        err = nla_parse_nested(tb,
                               CTA_PROTOINFO_SCTP_MAX,
                               attr,
                               sctp_nla_policy);
        if (err < 0)
                return err;

        if (!tb[CTA_PROTOINFO_SCTP_STATE] ||
            !tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL] ||
            !tb[CTA_PROTOINFO_SCTP_VTAG_REPLY])
                return -EINVAL;

        spin_lock_bh(&ct->lock);
        ct->proto.sctp.state = nla_get_u8(tb[CTA_PROTOINFO_SCTP_STATE]);
        ct->proto.sctp.vtag[IP_CT_DIR_ORIGINAL] =
                nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_ORIGINAL]);
        ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
                nla_get_be32(tb[CTA_PROTOINFO_SCTP_VTAG_REPLY]);
        spin_unlock_bh(&ct->lock);

        return 0;
}

static int sctp_nlattr_size(void)
{
        return nla_total_size(0)        /* CTA_PROTOINFO_SCTP */
                + nla_policy_len(sctp_nla_policy, CTA_PROTOINFO_SCTP_MAX + 1);
}
#endif

#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)

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

static int sctp_timeout_nlattr_to_obj(struct nlattr *tb[],
                                      struct net *net, void *data)
{
        unsigned int *timeouts = data;
        struct sctp_net *sn = sctp_pernet(net);
        int i;

        /* set default SCTP timeouts. */
        for (i=0; i<SCTP_CONNTRACK_MAX; i++)
                timeouts[i] = sn->timeouts[i];

        /* there's a 1:1 mapping between attributes and protocol states. */
        for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
                if (tb[i]) {
                        timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
                }
        }
        return 0;
}

static int
sctp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
        const unsigned int *timeouts = data;
        int i;

        for (i=CTA_TIMEOUT_SCTP_UNSPEC+1; i<CTA_TIMEOUT_SCTP_MAX+1; i++) {
                if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
                        goto nla_put_failure;
        }
        return 0;

nla_put_failure:
        return -ENOSPC;
}

static const struct nla_policy
sctp_timeout_nla_policy[CTA_TIMEOUT_SCTP_MAX+1] = {
        [CTA_TIMEOUT_SCTP_CLOSED]               = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_COOKIE_WAIT]          = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_COOKIE_ECHOED]        = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_ESTABLISHED]          = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_SHUTDOWN_SENT]        = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_SHUTDOWN_RECD]        = { .type = NLA_U32 },
        [CTA_TIMEOUT_SCTP_SHUTDOWN_ACK_SENT]    = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */


#ifdef CONFIG_SYSCTL
static struct ctl_table sctp_sysctl_table[] = {
        {
                .procname       = "nf_conntrack_sctp_timeout_closed",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_cookie_wait",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_cookie_echoed",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_established",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_shutdown_sent",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_shutdown_recd",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        { }
};

#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
static struct ctl_table sctp_compat_sysctl_table[] = {
        {
                .procname       = "ip_conntrack_sctp_timeout_closed",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_cookie_wait",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_cookie_echoed",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_established",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_shutdown_sent",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_shutdown_recd",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "ip_conntrack_sctp_timeout_shutdown_ack_sent",
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        { }
};
#endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
#endif

static int sctp_kmemdup_sysctl_table(struct nf_proto_net *pn,
                                     struct sctp_net *sn)
{
#ifdef CONFIG_SYSCTL
        if (pn->ctl_table)
                return 0;

        pn->ctl_table = kmemdup(sctp_sysctl_table,
                                sizeof(sctp_sysctl_table),
                                GFP_KERNEL);
        if (!pn->ctl_table)
                return -ENOMEM;

        pn->ctl_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
        pn->ctl_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
        pn->ctl_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
        pn->ctl_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
        pn->ctl_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
        pn->ctl_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
        pn->ctl_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
#endif
        return 0;
}

static int sctp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn,
                                            struct sctp_net *sn)
{
#ifdef CONFIG_SYSCTL
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
        pn->ctl_compat_table = kmemdup(sctp_compat_sysctl_table,
                                       sizeof(sctp_compat_sysctl_table),
                                       GFP_KERNEL);
        if (!pn->ctl_compat_table)
                return -ENOMEM;

        pn->ctl_compat_table[0].data = &sn->timeouts[SCTP_CONNTRACK_CLOSED];
        pn->ctl_compat_table[1].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_WAIT];
        pn->ctl_compat_table[2].data = &sn->timeouts[SCTP_CONNTRACK_COOKIE_ECHOED];
        pn->ctl_compat_table[3].data = &sn->timeouts[SCTP_CONNTRACK_ESTABLISHED];
        pn->ctl_compat_table[4].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT];
        pn->ctl_compat_table[5].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD];
        pn->ctl_compat_table[6].data = &sn->timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT];
#endif
#endif
        return 0;
}

static int sctp_init_net(struct net *net, u_int16_t proto)
{
        int ret;
        struct sctp_net *sn = sctp_pernet(net);
        struct nf_proto_net *pn = &sn->pn;

        if (!pn->users) {
                int i;

                for (i = 0; i < SCTP_CONNTRACK_MAX; i++)
                        sn->timeouts[i] = sctp_timeouts[i];
        }

        if (proto == AF_INET) {
                ret = sctp_kmemdup_compat_sysctl_table(pn, sn);
                if (ret < 0)
                        return ret;

                ret = sctp_kmemdup_sysctl_table(pn, sn);
                if (ret < 0)
                        nf_ct_kfree_compat_sysctl_table(pn);
        } else
                ret = sctp_kmemdup_sysctl_table(pn, sn);

        return ret;
}

static struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 __read_mostly = {
        .l3proto                = PF_INET,
        .l4proto                = IPPROTO_SCTP,
        .name                   = "sctp",
        .pkt_to_tuple           = sctp_pkt_to_tuple,
        .invert_tuple           = sctp_invert_tuple,
        .print_tuple            = sctp_print_tuple,
        .print_conntrack        = sctp_print_conntrack,
        .packet                 = sctp_packet,
        .get_timeouts           = sctp_get_timeouts,
        .new                    = sctp_new,
        .me                     = THIS_MODULE,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
        .to_nlattr              = sctp_to_nlattr,
        .nlattr_size            = sctp_nlattr_size,
        .from_nlattr            = nlattr_to_sctp,
        .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
        .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
        .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
        .nla_policy             = nf_ct_port_nla_policy,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
        .ctnl_timeout           = {
                .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
                .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
                .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
                .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
                .nla_policy     = sctp_timeout_nla_policy,
        },
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
        .net_id                 = &sctp_net_id,
        .init_net               = sctp_init_net,
};

static struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 __read_mostly = {
        .l3proto                = PF_INET6,
        .l4proto                = IPPROTO_SCTP,
        .name                   = "sctp",
        .pkt_to_tuple           = sctp_pkt_to_tuple,
        .invert_tuple           = sctp_invert_tuple,
        .print_tuple            = sctp_print_tuple,
        .print_conntrack        = sctp_print_conntrack,
        .packet                 = sctp_packet,
        .get_timeouts           = sctp_get_timeouts,
        .new                    = sctp_new,
        .me                     = THIS_MODULE,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
        .to_nlattr              = sctp_to_nlattr,
        .nlattr_size            = sctp_nlattr_size,
        .from_nlattr            = nlattr_to_sctp,
        .tuple_to_nlattr        = nf_ct_port_tuple_to_nlattr,
        .nlattr_tuple_size      = nf_ct_port_nlattr_tuple_size,
        .nlattr_to_tuple        = nf_ct_port_nlattr_to_tuple,
        .nla_policy             = nf_ct_port_nla_policy,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
        .ctnl_timeout           = {
                .nlattr_to_obj  = sctp_timeout_nlattr_to_obj,
                .obj_to_nlattr  = sctp_timeout_obj_to_nlattr,
                .nlattr_max     = CTA_TIMEOUT_SCTP_MAX,
                .obj_size       = sizeof(unsigned int) * SCTP_CONNTRACK_MAX,
                .nla_policy     = sctp_timeout_nla_policy,
        },
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
#endif
        .net_id                 = &sctp_net_id,
        .init_net               = sctp_init_net,
};

static int sctp_net_init(struct net *net)
{
        int ret = 0;

        ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_sctp4);
        if (ret < 0) {
                pr_err("nf_conntrack_sctp4: pernet registration failed.\n");
                goto out;
        }
        ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_sctp6);
        if (ret < 0) {
                pr_err("nf_conntrack_sctp6: pernet registration failed.\n");
                goto cleanup_sctp4;
        }
        return 0;

cleanup_sctp4:
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_sctp4);
out:
        return ret;
}

static void sctp_net_exit(struct net *net)
{
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_sctp6);
        nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_sctp4);
}

static struct pernet_operations sctp_net_ops = {
        .init = sctp_net_init,
        .exit = sctp_net_exit,
        .id   = &sctp_net_id,
        .size = sizeof(struct sctp_net),
};

static int __init nf_conntrack_proto_sctp_init(void)
{
        int ret;

        ret = register_pernet_subsys(&sctp_net_ops);
        if (ret < 0)
                goto out_pernet;

        ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_sctp4);
        if (ret < 0)
                goto out_sctp4;

        ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_sctp6);
        if (ret < 0)
                goto out_sctp6;

        return 0;
out_sctp6:
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_sctp4);
out_sctp4:
        unregister_pernet_subsys(&sctp_net_ops);
out_pernet:
        return ret;
}

static void __exit nf_conntrack_proto_sctp_fini(void)
{
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_sctp6);
        nf_ct_l4proto_unregister(&nf_conntrack_l4proto_sctp4);
        unregister_pernet_subsys(&sctp_net_ops);
}

module_init(nf_conntrack_proto_sctp_init);
module_exit(nf_conntrack_proto_sctp_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kiran Kumar Immidi");
MODULE_DESCRIPTION("Netfilter connection tracking protocol helper for SCTP");
MODULE_ALIAS("ip_conntrack_proto_sctp");