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root/net/netfilter/nf_conntrack_h323_main.c

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DEFINITIONS

This source file includes following definitions.
  1. get_tpkt_data
  2. get_h245_addr
  3. expect_rtp_rtcp
  4. expect_t120
  5. process_h245_channel
  6. process_olc
  7. process_olca
  8. process_h245
  9. h245_help
  10. get_h225_addr
  11. expect_h245
  12. callforward_do_filter
  13. expect_callforwarding
  14. process_setup
  15. process_callproceeding
  16. process_connect
  17. process_alerting
  18. process_facility
  19. process_progress
  20. process_q931
  21. q931_help
  22. get_udp_data
  23. find_expect
  24. set_expect_timeout
  25. expect_q931
  26. process_grq
  27. process_gcf
  28. process_rrq
  29. process_rcf
  30. process_urq
  31. process_arq
  32. process_acf
  33. process_lrq
  34. process_lcf
  35. process_irr
  36. process_ras
  37. ras_help
  38. nf_conntrack_h323_fini
  39. nf_conntrack_h323_init

/*
 * H.323 connection tracking helper
 *
 * Copyright (c) 2006 Jing Min Zhao <zhaojingmin@users.sourceforge.net>
 *
 * This source code is licensed under General Public License version 2.
 *
 * Based on the 'brute force' H.323 connection tracking module by
 * Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
 *
 * For more information, please see http://nath323.sourceforge.net/
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ctype.h>
#include <linux/inet.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/skbuff.h>
#include <net/route.h>
#include <net/ip6_route.h>

#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <linux/netfilter/nf_conntrack_h323.h>

/* Parameters */
static unsigned int default_rrq_ttl __read_mostly = 300;
module_param(default_rrq_ttl, uint, 0600);
MODULE_PARM_DESC(default_rrq_ttl, "use this TTL if it's missing in RRQ");

static int gkrouted_only __read_mostly = 1;
module_param(gkrouted_only, int, 0600);
MODULE_PARM_DESC(gkrouted_only, "only accept calls from gatekeeper");

static int callforward_filter __read_mostly = 1;
module_param(callforward_filter, bool, 0600);
MODULE_PARM_DESC(callforward_filter, "only create call forwarding expectations "
                                     "if both endpoints are on different sides "
                                     "(determined by routing information)");

/* Hooks for NAT */
int (*set_h245_addr_hook) (struct sk_buff *skb,
                           unsigned char **data, int dataoff,
                           H245_TransportAddress *taddr,
                           union nf_inet_addr *addr, __be16 port)
                           __read_mostly;
int (*set_h225_addr_hook) (struct sk_buff *skb,
                           unsigned char **data, int dataoff,
                           TransportAddress *taddr,
                           union nf_inet_addr *addr, __be16 port)
                           __read_mostly;
int (*set_sig_addr_hook) (struct sk_buff *skb,
                          struct nf_conn *ct,
                          enum ip_conntrack_info ctinfo,
                          unsigned char **data,
                          TransportAddress *taddr, int count) __read_mostly;
int (*set_ras_addr_hook) (struct sk_buff *skb,
                          struct nf_conn *ct,
                          enum ip_conntrack_info ctinfo,
                          unsigned char **data,
                          TransportAddress *taddr, int count) __read_mostly;
int (*nat_rtp_rtcp_hook) (struct sk_buff *skb,
                          struct nf_conn *ct,
                          enum ip_conntrack_info ctinfo,
                          unsigned char **data, int dataoff,
                          H245_TransportAddress *taddr,
                          __be16 port, __be16 rtp_port,
                          struct nf_conntrack_expect *rtp_exp,
                          struct nf_conntrack_expect *rtcp_exp) __read_mostly;
int (*nat_t120_hook) (struct sk_buff *skb,
                      struct nf_conn *ct,
                      enum ip_conntrack_info ctinfo,
                      unsigned char **data, int dataoff,
                      H245_TransportAddress *taddr, __be16 port,
                      struct nf_conntrack_expect *exp) __read_mostly;
int (*nat_h245_hook) (struct sk_buff *skb,
                      struct nf_conn *ct,
                      enum ip_conntrack_info ctinfo,
                      unsigned char **data, int dataoff,
                      TransportAddress *taddr, __be16 port,
                      struct nf_conntrack_expect *exp) __read_mostly;
int (*nat_callforwarding_hook) (struct sk_buff *skb,
                                struct nf_conn *ct,
                                enum ip_conntrack_info ctinfo,
                                unsigned char **data, int dataoff,
                                TransportAddress *taddr, __be16 port,
                                struct nf_conntrack_expect *exp) __read_mostly;
int (*nat_q931_hook) (struct sk_buff *skb,
                      struct nf_conn *ct,
                      enum ip_conntrack_info ctinfo,
                      unsigned char **data, TransportAddress *taddr, int idx,
                      __be16 port, struct nf_conntrack_expect *exp)
                      __read_mostly;

static DEFINE_SPINLOCK(nf_h323_lock);
static char *h323_buffer;

static struct nf_conntrack_helper nf_conntrack_helper_h245;
static struct nf_conntrack_helper nf_conntrack_helper_q931[];
static struct nf_conntrack_helper nf_conntrack_helper_ras[];

/****************************************************************************/
static int get_tpkt_data(struct sk_buff *skb, unsigned int protoff,
                         struct nf_conn *ct, enum ip_conntrack_info ctinfo,
                         unsigned char **data, int *datalen, int *dataoff)
{
        struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int dir = CTINFO2DIR(ctinfo);
        const struct tcphdr *th;
        struct tcphdr _tcph;
        int tcpdatalen;
        int tcpdataoff;
        unsigned char *tpkt;
        int tpktlen;
        int tpktoff;

        /* Get TCP header */
        th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
        if (th == NULL)
                return 0;

        /* Get TCP data offset */
        tcpdataoff = protoff + th->doff * 4;

        /* Get TCP data length */
        tcpdatalen = skb->len - tcpdataoff;
        if (tcpdatalen <= 0)    /* No TCP data */
                goto clear_out;

        if (*data == NULL) {    /* first TPKT */
                /* Get first TPKT pointer */
                tpkt = skb_header_pointer(skb, tcpdataoff, tcpdatalen,
                                          h323_buffer);
                BUG_ON(tpkt == NULL);

                /* Validate TPKT identifier */
                if (tcpdatalen < 4 || tpkt[0] != 0x03 || tpkt[1] != 0) {
                        /* Netmeeting sends TPKT header and data separately */
                        if (info->tpkt_len[dir] > 0) {
                                pr_debug("nf_ct_h323: previous packet "
                                         "indicated separate TPKT data of %hu "
                                         "bytes\n", info->tpkt_len[dir]);
                                if (info->tpkt_len[dir] <= tcpdatalen) {
                                        /* Yes, there was a TPKT header
                                         * received */
                                        *data = tpkt;
                                        *datalen = info->tpkt_len[dir];
                                        *dataoff = 0;
                                        goto out;
                                }

                                /* Fragmented TPKT */
                                pr_debug("nf_ct_h323: fragmented TPKT\n");
                                goto clear_out;
                        }

                        /* It is not even a TPKT */
                        return 0;
                }
                tpktoff = 0;
        } else {                /* Next TPKT */
                tpktoff = *dataoff + *datalen;
                tcpdatalen -= tpktoff;
                if (tcpdatalen <= 4)    /* No more TPKT */
                        goto clear_out;
                tpkt = *data + *datalen;

                /* Validate TPKT identifier */
                if (tpkt[0] != 0x03 || tpkt[1] != 0)
                        goto clear_out;
        }

        /* Validate TPKT length */
        tpktlen = tpkt[2] * 256 + tpkt[3];
        if (tpktlen < 4)
                goto clear_out;
        if (tpktlen > tcpdatalen) {
                if (tcpdatalen == 4) {  /* Separate TPKT header */
                        /* Netmeeting sends TPKT header and data separately */
                        pr_debug("nf_ct_h323: separate TPKT header indicates "
                                 "there will be TPKT data of %hu bytes\n",
                                 tpktlen - 4);
                        info->tpkt_len[dir] = tpktlen - 4;
                        return 0;
                }

                if (net_ratelimit())
                        printk("nf_ct_h323: incomplete TPKT (fragmented?)\n");
                goto clear_out;
        }

        /* This is the encapsulated data */
        *data = tpkt + 4;
        *datalen = tpktlen - 4;
        *dataoff = tpktoff + 4;

      out:
        /* Clear TPKT length */
        info->tpkt_len[dir] = 0;
        return 1;

      clear_out:
        info->tpkt_len[dir] = 0;
        return 0;
}

/****************************************************************************/
static int get_h245_addr(struct nf_conn *ct, const unsigned char *data,
                         H245_TransportAddress *taddr,
                         union nf_inet_addr *addr, __be16 *port)
{
        const unsigned char *p;
        int len;

        if (taddr->choice != eH245_TransportAddress_unicastAddress)
                return 0;

        switch (taddr->unicastAddress.choice) {
        case eUnicastAddress_iPAddress:
                if (nf_ct_l3num(ct) != AF_INET)
                        return 0;
                p = data + taddr->unicastAddress.iPAddress.network;
                len = 4;
                break;
        case eUnicastAddress_iP6Address:
                if (nf_ct_l3num(ct) != AF_INET6)
                        return 0;
                p = data + taddr->unicastAddress.iP6Address.network;
                len = 16;
                break;
        default:
                return 0;
        }

        memcpy(addr, p, len);
        memset((void *)addr + len, 0, sizeof(*addr) - len);
        memcpy(port, p + len, sizeof(__be16));

        return 1;
}

/****************************************************************************/
static int expect_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
                           enum ip_conntrack_info ctinfo,
                           unsigned char **data, int dataoff,
                           H245_TransportAddress *taddr)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        __be16 rtp_port, rtcp_port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *rtp_exp;
        struct nf_conntrack_expect *rtcp_exp;
        typeof(nat_rtp_rtcp_hook) nat_rtp_rtcp;

        /* Read RTP or RTCP address */
        if (!get_h245_addr(ct, *data, taddr, &addr, &port) ||
            memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) ||
            port == 0)
                return 0;

        /* RTP port is even */
        port &= htons(~1);
        rtp_port = port;
        rtcp_port = htons(ntohs(port) + 1);

        /* Create expect for RTP */
        if ((rtp_exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(rtp_exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3,
                          &ct->tuplehash[!dir].tuple.dst.u3,
                          IPPROTO_UDP, NULL, &rtp_port);

        /* Create expect for RTCP */
        if ((rtcp_exp = nf_ct_expect_alloc(ct)) == NULL) {
                nf_ct_expect_put(rtp_exp);
                return -1;
        }
        nf_ct_expect_init(rtcp_exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3,
                          &ct->tuplehash[!dir].tuple.dst.u3,
                          IPPROTO_UDP, NULL, &rtcp_port);

        if (memcmp(&ct->tuplehash[dir].tuple.src.u3,
                   &ct->tuplehash[!dir].tuple.dst.u3,
                   sizeof(ct->tuplehash[dir].tuple.src.u3)) &&
                   (nat_rtp_rtcp = rcu_dereference(nat_rtp_rtcp_hook)) &&
                   ct->status & IPS_NAT_MASK) {
                /* NAT needed */
                ret = nat_rtp_rtcp(skb, ct, ctinfo, data, dataoff,
                                   taddr, port, rtp_port, rtp_exp, rtcp_exp);
        } else {                /* Conntrack only */
                if (nf_ct_expect_related(rtp_exp) == 0) {
                        if (nf_ct_expect_related(rtcp_exp) == 0) {
                                pr_debug("nf_ct_h323: expect RTP ");
                                nf_ct_dump_tuple(&rtp_exp->tuple);
                                pr_debug("nf_ct_h323: expect RTCP ");
                                nf_ct_dump_tuple(&rtcp_exp->tuple);
                        } else {
                                nf_ct_unexpect_related(rtp_exp);
                                ret = -1;
                        }
                } else
                        ret = -1;
        }

        nf_ct_expect_put(rtp_exp);
        nf_ct_expect_put(rtcp_exp);

        return ret;
}

/****************************************************************************/
static int expect_t120(struct sk_buff *skb,
                       struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, int dataoff,
                       H245_TransportAddress *taddr)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;
        typeof(nat_t120_hook) nat_t120;

        /* Read T.120 address */
        if (!get_h245_addr(ct, *data, taddr, &addr, &port) ||
            memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) ||
            port == 0)
                return 0;

        /* Create expect for T.120 connections */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3,
                          &ct->tuplehash[!dir].tuple.dst.u3,
                          IPPROTO_TCP, NULL, &port);
        exp->flags = NF_CT_EXPECT_PERMANENT;    /* Accept multiple channels */

        if (memcmp(&ct->tuplehash[dir].tuple.src.u3,
                   &ct->tuplehash[!dir].tuple.dst.u3,
                   sizeof(ct->tuplehash[dir].tuple.src.u3)) &&
            (nat_t120 = rcu_dereference(nat_t120_hook)) &&
            ct->status & IPS_NAT_MASK) {
                /* NAT needed */
                ret = nat_t120(skb, ct, ctinfo, data, dataoff, taddr,
                               port, exp);
        } else {                /* Conntrack only */
                if (nf_ct_expect_related(exp) == 0) {
                        pr_debug("nf_ct_h323: expect T.120 ");
                        nf_ct_dump_tuple(&exp->tuple);
                } else
                        ret = -1;
        }

        nf_ct_expect_put(exp);

        return ret;
}

/****************************************************************************/
static int process_h245_channel(struct sk_buff *skb,
                                struct nf_conn *ct,
                                enum ip_conntrack_info ctinfo,
                                unsigned char **data, int dataoff,
                                H2250LogicalChannelParameters *channel)
{
        int ret;

        if (channel->options & eH2250LogicalChannelParameters_mediaChannel) {
                /* RTP */
                ret = expect_rtp_rtcp(skb, ct, ctinfo, data, dataoff,
                                      &channel->mediaChannel);
                if (ret < 0)
                        return -1;
        }

        if (channel->
            options & eH2250LogicalChannelParameters_mediaControlChannel) {
                /* RTCP */
                ret = expect_rtp_rtcp(skb, ct, ctinfo, data, dataoff,
                                      &channel->mediaControlChannel);
                if (ret < 0)
                        return -1;
        }

        return 0;
}

/****************************************************************************/
static int process_olc(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, int dataoff,
                       OpenLogicalChannel *olc)
{
        int ret;

        pr_debug("nf_ct_h323: OpenLogicalChannel\n");

        if (olc->forwardLogicalChannelParameters.multiplexParameters.choice ==
            eOpenLogicalChannel_forwardLogicalChannelParameters_multiplexParameters_h2250LogicalChannelParameters)
        {
                ret = process_h245_channel(skb, ct, ctinfo, data, dataoff,
                                           &olc->
                                           forwardLogicalChannelParameters.
                                           multiplexParameters.
                                           h2250LogicalChannelParameters);
                if (ret < 0)
                        return -1;
        }

        if ((olc->options &
             eOpenLogicalChannel_reverseLogicalChannelParameters) &&
            (olc->reverseLogicalChannelParameters.options &
             eOpenLogicalChannel_reverseLogicalChannelParameters_multiplexParameters)
            && (olc->reverseLogicalChannelParameters.multiplexParameters.
                choice ==
                eOpenLogicalChannel_reverseLogicalChannelParameters_multiplexParameters_h2250LogicalChannelParameters))
        {
                ret =
                    process_h245_channel(skb, ct, ctinfo, data, dataoff,
                                         &olc->
                                         reverseLogicalChannelParameters.
                                         multiplexParameters.
                                         h2250LogicalChannelParameters);
                if (ret < 0)
                        return -1;
        }

        if ((olc->options & eOpenLogicalChannel_separateStack) &&
            olc->forwardLogicalChannelParameters.dataType.choice ==
            eDataType_data &&
            olc->forwardLogicalChannelParameters.dataType.data.application.
            choice == eDataApplicationCapability_application_t120 &&
            olc->forwardLogicalChannelParameters.dataType.data.application.
            t120.choice == eDataProtocolCapability_separateLANStack &&
            olc->separateStack.networkAddress.choice ==
            eNetworkAccessParameters_networkAddress_localAreaAddress) {
                ret = expect_t120(skb, ct, ctinfo, data, dataoff,
                                  &olc->separateStack.networkAddress.
                                  localAreaAddress);
                if (ret < 0)
                        return -1;
        }

        return 0;
}

/****************************************************************************/
static int process_olca(struct sk_buff *skb, struct nf_conn *ct,
                        enum ip_conntrack_info ctinfo,
                        unsigned char **data, int dataoff,
                        OpenLogicalChannelAck *olca)
{
        H2250LogicalChannelAckParameters *ack;
        int ret;

        pr_debug("nf_ct_h323: OpenLogicalChannelAck\n");

        if ((olca->options &
             eOpenLogicalChannelAck_reverseLogicalChannelParameters) &&
            (olca->reverseLogicalChannelParameters.options &
             eOpenLogicalChannelAck_reverseLogicalChannelParameters_multiplexParameters)
            && (olca->reverseLogicalChannelParameters.multiplexParameters.
                choice ==
                eOpenLogicalChannelAck_reverseLogicalChannelParameters_multiplexParameters_h2250LogicalChannelParameters))
        {
                ret = process_h245_channel(skb, ct, ctinfo, data, dataoff,
                                           &olca->
                                           reverseLogicalChannelParameters.
                                           multiplexParameters.
                                           h2250LogicalChannelParameters);
                if (ret < 0)
                        return -1;
        }

        if ((olca->options &
             eOpenLogicalChannelAck_forwardMultiplexAckParameters) &&
            (olca->forwardMultiplexAckParameters.choice ==
             eOpenLogicalChannelAck_forwardMultiplexAckParameters_h2250LogicalChannelAckParameters))
        {
                ack = &olca->forwardMultiplexAckParameters.
                    h2250LogicalChannelAckParameters;
                if (ack->options &
                    eH2250LogicalChannelAckParameters_mediaChannel) {
                        /* RTP */
                        ret = expect_rtp_rtcp(skb, ct, ctinfo, data, dataoff,
                                              &ack->mediaChannel);
                        if (ret < 0)
                                return -1;
                }

                if (ack->options &
                    eH2250LogicalChannelAckParameters_mediaControlChannel) {
                        /* RTCP */
                        ret = expect_rtp_rtcp(skb, ct, ctinfo, data, dataoff,
                                              &ack->mediaControlChannel);
                        if (ret < 0)
                                return -1;
                }
        }

        if ((olca->options & eOpenLogicalChannelAck_separateStack) &&
                olca->separateStack.networkAddress.choice ==
                eNetworkAccessParameters_networkAddress_localAreaAddress) {
                ret = expect_t120(skb, ct, ctinfo, data, dataoff,
                                  &olca->separateStack.networkAddress.
                                  localAreaAddress);
                if (ret < 0)
                        return -1;
        }

        return 0;
}

/****************************************************************************/
static int process_h245(struct sk_buff *skb, struct nf_conn *ct,
                        enum ip_conntrack_info ctinfo,
                        unsigned char **data, int dataoff,
                        MultimediaSystemControlMessage *mscm)
{
        switch (mscm->choice) {
        case eMultimediaSystemControlMessage_request:
                if (mscm->request.choice ==
                    eRequestMessage_openLogicalChannel) {
                        return process_olc(skb, ct, ctinfo, data, dataoff,
                                           &mscm->request.openLogicalChannel);
                }
                pr_debug("nf_ct_h323: H.245 Request %d\n",
                         mscm->request.choice);
                break;
        case eMultimediaSystemControlMessage_response:
                if (mscm->response.choice ==
                    eResponseMessage_openLogicalChannelAck) {
                        return process_olca(skb, ct, ctinfo, data, dataoff,
                                            &mscm->response.
                                            openLogicalChannelAck);
                }
                pr_debug("nf_ct_h323: H.245 Response %d\n",
                         mscm->response.choice);
                break;
        default:
                pr_debug("nf_ct_h323: H.245 signal %d\n", mscm->choice);
                break;
        }

        return 0;
}

/****************************************************************************/
static int h245_help(struct sk_buff *skb, unsigned int protoff,
                     struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
        static MultimediaSystemControlMessage mscm;
        unsigned char *data = NULL;
        int datalen;
        int dataoff;
        int ret;

        /* Until there's been traffic both ways, don't look in packets. */
        if (ctinfo != IP_CT_ESTABLISHED &&
            ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
                return NF_ACCEPT;
        }
        pr_debug("nf_ct_h245: skblen = %u\n", skb->len);

        spin_lock_bh(&nf_h323_lock);

        /* Process each TPKT */
        while (get_tpkt_data(skb, protoff, ct, ctinfo,
                             &data, &datalen, &dataoff)) {
                pr_debug("nf_ct_h245: TPKT len=%d ", datalen);
                nf_ct_dump_tuple(&ct->tuplehash[CTINFO2DIR(ctinfo)].tuple);

                /* Decode H.245 signal */
                ret = DecodeMultimediaSystemControlMessage(data, datalen,
                                                           &mscm);
                if (ret < 0) {
                        pr_debug("nf_ct_h245: decoding error: %s\n",
                                 ret == H323_ERROR_BOUND ?
                                 "out of bound" : "out of range");
                        /* We don't drop when decoding error */
                        break;
                }

                /* Process H.245 signal */
                if (process_h245(skb, ct, ctinfo, &data, dataoff, &mscm) < 0)
                        goto drop;
        }

        spin_unlock_bh(&nf_h323_lock);
        return NF_ACCEPT;

      drop:
        spin_unlock_bh(&nf_h323_lock);
        if (net_ratelimit())
                printk("nf_ct_h245: packet dropped\n");
        return NF_DROP;
}

/****************************************************************************/
static const struct nf_conntrack_expect_policy h245_exp_policy = {
        .max_expected   = H323_RTP_CHANNEL_MAX * 4 + 2 /* T.120 */,
        .timeout        = 240,
};

static struct nf_conntrack_helper nf_conntrack_helper_h245 __read_mostly = {
        .name                   = "H.245",
        .me                     = THIS_MODULE,
        .tuple.src.l3num        = AF_UNSPEC,
        .tuple.dst.protonum     = IPPROTO_UDP,
        .help                   = h245_help,
        .expect_policy          = &h245_exp_policy,
};

/****************************************************************************/
int get_h225_addr(struct nf_conn *ct, unsigned char *data,
                  TransportAddress *taddr,
                  union nf_inet_addr *addr, __be16 *port)
{
        const unsigned char *p;
        int len;

        switch (taddr->choice) {
        case eTransportAddress_ipAddress:
                if (nf_ct_l3num(ct) != AF_INET)
                        return 0;
                p = data + taddr->ipAddress.ip;
                len = 4;
                break;
        case eTransportAddress_ip6Address:
                if (nf_ct_l3num(ct) != AF_INET6)
                        return 0;
                p = data + taddr->ip6Address.ip;
                len = 16;
                break;
        default:
                return 0;
        }

        memcpy(addr, p, len);
        memset((void *)addr + len, 0, sizeof(*addr) - len);
        memcpy(port, p + len, sizeof(__be16));

        return 1;
}

/****************************************************************************/
static int expect_h245(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, int dataoff,
                       TransportAddress *taddr)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;
        typeof(nat_h245_hook) nat_h245;

        /* Read h245Address */
        if (!get_h225_addr(ct, *data, taddr, &addr, &port) ||
            memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) ||
            port == 0)
                return 0;

        /* Create expect for h245 connection */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3,
                          &ct->tuplehash[!dir].tuple.dst.u3,
                          IPPROTO_TCP, NULL, &port);
        exp->helper = &nf_conntrack_helper_h245;

        if (memcmp(&ct->tuplehash[dir].tuple.src.u3,
                   &ct->tuplehash[!dir].tuple.dst.u3,
                   sizeof(ct->tuplehash[dir].tuple.src.u3)) &&
            (nat_h245 = rcu_dereference(nat_h245_hook)) &&
            ct->status & IPS_NAT_MASK) {
                /* NAT needed */
                ret = nat_h245(skb, ct, ctinfo, data, dataoff, taddr,
                               port, exp);
        } else {                /* Conntrack only */
                if (nf_ct_expect_related(exp) == 0) {
                        pr_debug("nf_ct_q931: expect H.245 ");
                        nf_ct_dump_tuple(&exp->tuple);
                } else
                        ret = -1;
        }

        nf_ct_expect_put(exp);

        return ret;
}

/* If the calling party is on the same side of the forward-to party,
 * we don't need to track the second call */
static int callforward_do_filter(const union nf_inet_addr *src,
                                 const union nf_inet_addr *dst,
                                 u_int8_t family)
{
        const struct nf_afinfo *afinfo;
        struct flowi fl1, fl2;
        int ret = 0;

        /* rcu_read_lock()ed by nf_hook_slow() */
        afinfo = nf_get_afinfo(family);
        if (!afinfo)
                return 0;

        memset(&fl1, 0, sizeof(fl1));
        memset(&fl2, 0, sizeof(fl2));

        switch (family) {
        case AF_INET: {
                struct rtable *rt1, *rt2;

                fl1.fl4_dst = src->ip;
                fl2.fl4_dst = dst->ip;
                if (!afinfo->route((struct dst_entry **)&rt1, &fl1)) {
                        if (!afinfo->route((struct dst_entry **)&rt2, &fl2)) {
                                if (rt1->rt_gateway == rt2->rt_gateway &&
                                    rt1->u.dst.dev  == rt2->u.dst.dev)
                                        ret = 1;
                                dst_release(&rt2->u.dst);
                        }
                        dst_release(&rt1->u.dst);
                }
                break;
        }
#if defined(CONFIG_NF_CONNTRACK_IPV6) || \
    defined(CONFIG_NF_CONNTRACK_IPV6_MODULE)
        case AF_INET6: {
                struct rt6_info *rt1, *rt2;

                memcpy(&fl1.fl6_dst, src, sizeof(fl1.fl6_dst));
                memcpy(&fl2.fl6_dst, dst, sizeof(fl2.fl6_dst));
                if (!afinfo->route((struct dst_entry **)&rt1, &fl1)) {
                        if (!afinfo->route((struct dst_entry **)&rt2, &fl2)) {
                                if (!memcmp(&rt1->rt6i_gateway, &rt2->rt6i_gateway,
                                            sizeof(rt1->rt6i_gateway)) &&
                                    rt1->u.dst.dev == rt2->u.dst.dev)
                                        ret = 1;
                                dst_release(&rt2->u.dst);
                        }
                        dst_release(&rt1->u.dst);
                }
                break;
        }
#endif
        }
        return ret;

}

/****************************************************************************/
static int expect_callforwarding(struct sk_buff *skb,
                                 struct nf_conn *ct,
                                 enum ip_conntrack_info ctinfo,
                                 unsigned char **data, int dataoff,
                                 TransportAddress *taddr)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;
        typeof(nat_callforwarding_hook) nat_callforwarding;

        /* Read alternativeAddress */
        if (!get_h225_addr(ct, *data, taddr, &addr, &port) || port == 0)
                return 0;

        /* If the calling party is on the same side of the forward-to party,
         * we don't need to track the second call */
        if (callforward_filter &&
            callforward_do_filter(&addr, &ct->tuplehash[!dir].tuple.src.u3,
                                  nf_ct_l3num(ct))) {
                pr_debug("nf_ct_q931: Call Forwarding not tracked\n");
                return 0;
        }

        /* Create expect for the second call leg */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3, &addr,
                          IPPROTO_TCP, NULL, &port);
        exp->helper = nf_conntrack_helper_q931;

        if (memcmp(&ct->tuplehash[dir].tuple.src.u3,
                   &ct->tuplehash[!dir].tuple.dst.u3,
                   sizeof(ct->tuplehash[dir].tuple.src.u3)) &&
            (nat_callforwarding = rcu_dereference(nat_callforwarding_hook)) &&
            ct->status & IPS_NAT_MASK) {
                /* Need NAT */
                ret = nat_callforwarding(skb, ct, ctinfo, data, dataoff,
                                         taddr, port, exp);
        } else {                /* Conntrack only */
                if (nf_ct_expect_related(exp) == 0) {
                        pr_debug("nf_ct_q931: expect Call Forwarding ");
                        nf_ct_dump_tuple(&exp->tuple);
                } else
                        ret = -1;
        }

        nf_ct_expect_put(exp);

        return ret;
}

/****************************************************************************/
static int process_setup(struct sk_buff *skb, struct nf_conn *ct,
                         enum ip_conntrack_info ctinfo,
                         unsigned char **data, int dataoff,
                         Setup_UUIE *setup)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret;
        int i;
        __be16 port;
        union nf_inet_addr addr;
        typeof(set_h225_addr_hook) set_h225_addr;

        pr_debug("nf_ct_q931: Setup\n");

        if (setup->options & eSetup_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &setup->h245Address);
                if (ret < 0)
                        return -1;
        }

        set_h225_addr = rcu_dereference(set_h225_addr_hook);
        if ((setup->options & eSetup_UUIE_destCallSignalAddress) &&
            (set_h225_addr) && ct->status & IPS_NAT_MASK &&
            get_h225_addr(ct, *data, &setup->destCallSignalAddress,
                          &addr, &port) &&
            memcmp(&addr, &ct->tuplehash[!dir].tuple.src.u3, sizeof(addr))) {
                pr_debug("nf_ct_q931: set destCallSignalAddress "
                         NIP6_FMT ":%hu->" NIP6_FMT ":%hu\n",
                         NIP6(*(struct in6_addr *)&addr), ntohs(port),
                         NIP6(*(struct in6_addr *)&ct->tuplehash[!dir].tuple.src.u3),
                         ntohs(ct->tuplehash[!dir].tuple.src.u.tcp.port));
                ret = set_h225_addr(skb, data, dataoff,
                                    &setup->destCallSignalAddress,
                                    &ct->tuplehash[!dir].tuple.src.u3,
                                    ct->tuplehash[!dir].tuple.src.u.tcp.port);
                if (ret < 0)
                        return -1;
        }

        if ((setup->options & eSetup_UUIE_sourceCallSignalAddress) &&
            (set_h225_addr) && ct->status & IPS_NAT_MASK &&
            get_h225_addr(ct, *data, &setup->sourceCallSignalAddress,
                          &addr, &port) &&
            memcmp(&addr, &ct->tuplehash[!dir].tuple.dst.u3, sizeof(addr))) {
                pr_debug("nf_ct_q931: set sourceCallSignalAddress "
                         NIP6_FMT ":%hu->" NIP6_FMT ":%hu\n",
                         NIP6(*(struct in6_addr *)&addr), ntohs(port),
                         NIP6(*(struct in6_addr *)&ct->tuplehash[!dir].tuple.dst.u3),
                         ntohs(ct->tuplehash[!dir].tuple.dst.u.tcp.port));
                ret = set_h225_addr(skb, data, dataoff,
                                    &setup->sourceCallSignalAddress,
                                    &ct->tuplehash[!dir].tuple.dst.u3,
                                    ct->tuplehash[!dir].tuple.dst.u.tcp.port);
                if (ret < 0)
                        return -1;
        }

        if (setup->options & eSetup_UUIE_fastStart) {
                for (i = 0; i < setup->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &setup->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_callproceeding(struct sk_buff *skb,
                                  struct nf_conn *ct,
                                  enum ip_conntrack_info ctinfo,
                                  unsigned char **data, int dataoff,
                                  CallProceeding_UUIE *callproc)
{
        int ret;
        int i;

        pr_debug("nf_ct_q931: CallProceeding\n");

        if (callproc->options & eCallProceeding_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &callproc->h245Address);
                if (ret < 0)
                        return -1;
        }

        if (callproc->options & eCallProceeding_UUIE_fastStart) {
                for (i = 0; i < callproc->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &callproc->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_connect(struct sk_buff *skb, struct nf_conn *ct,
                           enum ip_conntrack_info ctinfo,
                           unsigned char **data, int dataoff,
                           Connect_UUIE *connect)
{
        int ret;
        int i;

        pr_debug("nf_ct_q931: Connect\n");

        if (connect->options & eConnect_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &connect->h245Address);
                if (ret < 0)
                        return -1;
        }

        if (connect->options & eConnect_UUIE_fastStart) {
                for (i = 0; i < connect->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &connect->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_alerting(struct sk_buff *skb, struct nf_conn *ct,
                            enum ip_conntrack_info ctinfo,
                            unsigned char **data, int dataoff,
                            Alerting_UUIE *alert)
{
        int ret;
        int i;

        pr_debug("nf_ct_q931: Alerting\n");

        if (alert->options & eAlerting_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &alert->h245Address);
                if (ret < 0)
                        return -1;
        }

        if (alert->options & eAlerting_UUIE_fastStart) {
                for (i = 0; i < alert->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &alert->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_facility(struct sk_buff *skb, struct nf_conn *ct,
                            enum ip_conntrack_info ctinfo,
                            unsigned char **data, int dataoff,
                            Facility_UUIE *facility)
{
        int ret;
        int i;

        pr_debug("nf_ct_q931: Facility\n");

        if (facility->reason.choice == eFacilityReason_callForwarded) {
                if (facility->options & eFacility_UUIE_alternativeAddress)
                        return expect_callforwarding(skb, ct, ctinfo, data,
                                                     dataoff,
                                                     &facility->
                                                     alternativeAddress);
                return 0;
        }

        if (facility->options & eFacility_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &facility->h245Address);
                if (ret < 0)
                        return -1;
        }

        if (facility->options & eFacility_UUIE_fastStart) {
                for (i = 0; i < facility->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &facility->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_progress(struct sk_buff *skb, struct nf_conn *ct,
                            enum ip_conntrack_info ctinfo,
                            unsigned char **data, int dataoff,
                            Progress_UUIE *progress)
{
        int ret;
        int i;

        pr_debug("nf_ct_q931: Progress\n");

        if (progress->options & eProgress_UUIE_h245Address) {
                ret = expect_h245(skb, ct, ctinfo, data, dataoff,
                                  &progress->h245Address);
                if (ret < 0)
                        return -1;
        }

        if (progress->options & eProgress_UUIE_fastStart) {
                for (i = 0; i < progress->fastStart.count; i++) {
                        ret = process_olc(skb, ct, ctinfo, data, dataoff,
                                          &progress->fastStart.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int process_q931(struct sk_buff *skb, struct nf_conn *ct,
                        enum ip_conntrack_info ctinfo,
                        unsigned char **data, int dataoff, Q931 *q931)
{
        H323_UU_PDU *pdu = &q931->UUIE.h323_uu_pdu;
        int i;
        int ret = 0;

        switch (pdu->h323_message_body.choice) {
        case eH323_UU_PDU_h323_message_body_setup:
                ret = process_setup(skb, ct, ctinfo, data, dataoff,
                                    &pdu->h323_message_body.setup);
                break;
        case eH323_UU_PDU_h323_message_body_callProceeding:
                ret = process_callproceeding(skb, ct, ctinfo, data, dataoff,
                                             &pdu->h323_message_body.
                                             callProceeding);
                break;
        case eH323_UU_PDU_h323_message_body_connect:
                ret = process_connect(skb, ct, ctinfo, data, dataoff,
                                      &pdu->h323_message_body.connect);
                break;
        case eH323_UU_PDU_h323_message_body_alerting:
                ret = process_alerting(skb, ct, ctinfo, data, dataoff,
                                       &pdu->h323_message_body.alerting);
                break;
        case eH323_UU_PDU_h323_message_body_facility:
                ret = process_facility(skb, ct, ctinfo, data, dataoff,
                                       &pdu->h323_message_body.facility);
                break;
        case eH323_UU_PDU_h323_message_body_progress:
                ret = process_progress(skb, ct, ctinfo, data, dataoff,
                                       &pdu->h323_message_body.progress);
                break;
        default:
                pr_debug("nf_ct_q931: Q.931 signal %d\n",
                         pdu->h323_message_body.choice);
                break;
        }

        if (ret < 0)
                return -1;

        if (pdu->options & eH323_UU_PDU_h245Control) {
                for (i = 0; i < pdu->h245Control.count; i++) {
                        ret = process_h245(skb, ct, ctinfo, data, dataoff,
                                           &pdu->h245Control.item[i]);
                        if (ret < 0)
                                return -1;
                }
        }

        return 0;
}

/****************************************************************************/
static int q931_help(struct sk_buff *skb, unsigned int protoff,
                     struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
        static Q931 q931;
        unsigned char *data = NULL;
        int datalen;
        int dataoff;
        int ret;

        /* Until there's been traffic both ways, don't look in packets. */
        if (ctinfo != IP_CT_ESTABLISHED &&
            ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
                return NF_ACCEPT;
        }
        pr_debug("nf_ct_q931: skblen = %u\n", skb->len);

        spin_lock_bh(&nf_h323_lock);

        /* Process each TPKT */
        while (get_tpkt_data(skb, protoff, ct, ctinfo,
                             &data, &datalen, &dataoff)) {
                pr_debug("nf_ct_q931: TPKT len=%d ", datalen);
                nf_ct_dump_tuple(&ct->tuplehash[CTINFO2DIR(ctinfo)].tuple);

                /* Decode Q.931 signal */
                ret = DecodeQ931(data, datalen, &q931);
                if (ret < 0) {
                        pr_debug("nf_ct_q931: decoding error: %s\n",
                                 ret == H323_ERROR_BOUND ?
                                 "out of bound" : "out of range");
                        /* We don't drop when decoding error */
                        break;
                }

                /* Process Q.931 signal */
                if (process_q931(skb, ct, ctinfo, &data, dataoff, &q931) < 0)
                        goto drop;
        }

        spin_unlock_bh(&nf_h323_lock);
        return NF_ACCEPT;

      drop:
        spin_unlock_bh(&nf_h323_lock);
        if (net_ratelimit())
                printk("nf_ct_q931: packet dropped\n");
        return NF_DROP;
}

/****************************************************************************/
static const struct nf_conntrack_expect_policy q931_exp_policy = {
        /* T.120 and H.245 */
        .max_expected           = H323_RTP_CHANNEL_MAX * 4 + 4,
        .timeout                = 240,
};

static struct nf_conntrack_helper nf_conntrack_helper_q931[] __read_mostly = {
        {
                .name                   = "Q.931",
                .me                     = THIS_MODULE,
                .tuple.src.l3num        = AF_INET,
                .tuple.src.u.tcp.port   = __constant_htons(Q931_PORT),
                .tuple.dst.protonum     = IPPROTO_TCP,
                .help                   = q931_help,
                .expect_policy          = &q931_exp_policy,
        },
        {
                .name                   = "Q.931",
                .me                     = THIS_MODULE,
                .tuple.src.l3num        = AF_INET6,
                .tuple.src.u.tcp.port   = __constant_htons(Q931_PORT),
                .tuple.dst.protonum     = IPPROTO_TCP,
                .help                   = q931_help,
                .expect_policy          = &q931_exp_policy,
        },
};

/****************************************************************************/
static unsigned char *get_udp_data(struct sk_buff *skb, unsigned int protoff,
                                   int *datalen)
{
        const struct udphdr *uh;
        struct udphdr _uh;
        int dataoff;

        uh = skb_header_pointer(skb, protoff, sizeof(_uh), &_uh);
        if (uh == NULL)
                return NULL;
        dataoff = protoff + sizeof(_uh);
        if (dataoff >= skb->len)
                return NULL;
        *datalen = skb->len - dataoff;
        return skb_header_pointer(skb, dataoff, *datalen, h323_buffer);
}

/****************************************************************************/
static struct nf_conntrack_expect *find_expect(struct nf_conn *ct,
                                               union nf_inet_addr *addr,
                                               __be16 port)
{
        struct net *net = nf_ct_net(ct);
        struct nf_conntrack_expect *exp;
        struct nf_conntrack_tuple tuple;

        memset(&tuple.src.u3, 0, sizeof(tuple.src.u3));
        tuple.src.u.tcp.port = 0;
        memcpy(&tuple.dst.u3, addr, sizeof(tuple.dst.u3));
        tuple.dst.u.tcp.port = port;
        tuple.dst.protonum = IPPROTO_TCP;

        exp = __nf_ct_expect_find(net, &tuple);
        if (exp && exp->master == ct)
                return exp;
        return NULL;
}

/****************************************************************************/
static int set_expect_timeout(struct nf_conntrack_expect *exp,
                              unsigned timeout)
{
        if (!exp || !del_timer(&exp->timeout))
                return 0;

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

        return 1;
}

/****************************************************************************/
static int expect_q931(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data,
                       TransportAddress *taddr, int count)
{
        struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        int i;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;
        typeof(nat_q931_hook) nat_q931;

        /* Look for the first related address */
        for (i = 0; i < count; i++) {
                if (get_h225_addr(ct, *data, &taddr[i], &addr, &port) &&
                    memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3,
                           sizeof(addr)) == 0 && port != 0)
                        break;
        }

        if (i >= count)         /* Not found */
                return 0;

        /* Create expect for Q.931 */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          gkrouted_only ? /* only accept calls from GK? */
                                &ct->tuplehash[!dir].tuple.src.u3 : NULL,
                          &ct->tuplehash[!dir].tuple.dst.u3,
                          IPPROTO_TCP, NULL, &port);
        exp->helper = nf_conntrack_helper_q931;
        exp->flags = NF_CT_EXPECT_PERMANENT;    /* Accept multiple calls */

        nat_q931 = rcu_dereference(nat_q931_hook);
        if (nat_q931 && ct->status & IPS_NAT_MASK) {    /* Need NAT */
                ret = nat_q931(skb, ct, ctinfo, data, taddr, i, port, exp);
        } else {                /* Conntrack only */
                if (nf_ct_expect_related(exp) == 0) {
                        pr_debug("nf_ct_ras: expect Q.931 ");
                        nf_ct_dump_tuple(&exp->tuple);

                        /* Save port for looking up expect in processing RCF */
                        info->sig_port[dir] = port;
                } else
                        ret = -1;
        }

        nf_ct_expect_put(exp);

        return ret;
}

/****************************************************************************/
static int process_grq(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, GatekeeperRequest *grq)
{
        typeof(set_ras_addr_hook) set_ras_addr;

        pr_debug("nf_ct_ras: GRQ\n");

        set_ras_addr = rcu_dereference(set_ras_addr_hook);
        if (set_ras_addr && ct->status & IPS_NAT_MASK)  /* NATed */
                return set_ras_addr(skb, ct, ctinfo, data,
                                    &grq->rasAddress, 1);
        return 0;
}

/****************************************************************************/
static int process_gcf(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, GatekeeperConfirm *gcf)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;

        pr_debug("nf_ct_ras: GCF\n");

        if (!get_h225_addr(ct, *data, &gcf->rasAddress, &addr, &port))
                return 0;

        /* Registration port is the same as discovery port */
        if (!memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) &&
            port == ct->tuplehash[dir].tuple.src.u.udp.port)
                return 0;

        /* Avoid RAS expectation loops. A GCF is never expected. */
        if (test_bit(IPS_EXPECTED_BIT, &ct->status))
                return 0;

        /* Need new expect */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3, &addr,
                          IPPROTO_UDP, NULL, &port);
        exp->helper = nf_conntrack_helper_ras;

        if (nf_ct_expect_related(exp) == 0) {
                pr_debug("nf_ct_ras: expect RAS ");
                nf_ct_dump_tuple(&exp->tuple);
        } else
                ret = -1;

        nf_ct_expect_put(exp);

        return ret;
}

/****************************************************************************/
static int process_rrq(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, RegistrationRequest *rrq)
{
        struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int ret;
        typeof(set_ras_addr_hook) set_ras_addr;

        pr_debug("nf_ct_ras: RRQ\n");

        ret = expect_q931(skb, ct, ctinfo, data,
                          rrq->callSignalAddress.item,
                          rrq->callSignalAddress.count);
        if (ret < 0)
                return -1;

        set_ras_addr = rcu_dereference(set_ras_addr_hook);
        if (set_ras_addr && ct->status & IPS_NAT_MASK) {
                ret = set_ras_addr(skb, ct, ctinfo, data,
                                   rrq->rasAddress.item,
                                   rrq->rasAddress.count);
                if (ret < 0)
                        return -1;
        }

        if (rrq->options & eRegistrationRequest_timeToLive) {
                pr_debug("nf_ct_ras: RRQ TTL = %u seconds\n", rrq->timeToLive);
                info->timeout = rrq->timeToLive;
        } else
                info->timeout = default_rrq_ttl;

        return 0;
}

/****************************************************************************/
static int process_rcf(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, RegistrationConfirm *rcf)
{
        struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int dir = CTINFO2DIR(ctinfo);
        int ret;
        struct nf_conntrack_expect *exp;
        typeof(set_sig_addr_hook) set_sig_addr;

        pr_debug("nf_ct_ras: RCF\n");

        set_sig_addr = rcu_dereference(set_sig_addr_hook);
        if (set_sig_addr && ct->status & IPS_NAT_MASK) {
                ret = set_sig_addr(skb, ct, ctinfo, data,
                                        rcf->callSignalAddress.item,
                                        rcf->callSignalAddress.count);
                if (ret < 0)
                        return -1;
        }

        if (rcf->options & eRegistrationConfirm_timeToLive) {
                pr_debug("nf_ct_ras: RCF TTL = %u seconds\n", rcf->timeToLive);
                info->timeout = rcf->timeToLive;
        }

        if (info->timeout > 0) {
                pr_debug("nf_ct_ras: set RAS connection timeout to "
                         "%u seconds\n", info->timeout);
                nf_ct_refresh(ct, skb, info->timeout * HZ);

                /* Set expect timeout */
                spin_lock_bh(&nf_conntrack_lock);
                exp = find_expect(ct, &ct->tuplehash[dir].tuple.dst.u3,
                                  info->sig_port[!dir]);
                if (exp) {
                        pr_debug("nf_ct_ras: set Q.931 expect "
                                 "timeout to %u seconds for",
                                 info->timeout);
                        nf_ct_dump_tuple(&exp->tuple);
                        set_expect_timeout(exp, info->timeout);
                }
                spin_unlock_bh(&nf_conntrack_lock);
        }

        return 0;
}

/****************************************************************************/
static int process_urq(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, UnregistrationRequest *urq)
{
        struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int dir = CTINFO2DIR(ctinfo);
        int ret;
        typeof(set_sig_addr_hook) set_sig_addr;

        pr_debug("nf_ct_ras: URQ\n");

        set_sig_addr = rcu_dereference(set_sig_addr_hook);
        if (set_sig_addr && ct->status & IPS_NAT_MASK) {
                ret = set_sig_addr(skb, ct, ctinfo, data,
                                   urq->callSignalAddress.item,
                                   urq->callSignalAddress.count);
                if (ret < 0)
                        return -1;
        }

        /* Clear old expect */
        nf_ct_remove_expectations(ct);
        info->sig_port[dir] = 0;
        info->sig_port[!dir] = 0;

        /* Give it 30 seconds for UCF or URJ */
        nf_ct_refresh(ct, skb, 30 * HZ);

        return 0;
}

/****************************************************************************/
static int process_arq(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, AdmissionRequest *arq)
{
        const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
        int dir = CTINFO2DIR(ctinfo);
        __be16 port;
        union nf_inet_addr addr;
        typeof(set_h225_addr_hook) set_h225_addr;

        pr_debug("nf_ct_ras: ARQ\n");

        set_h225_addr = rcu_dereference(set_h225_addr_hook);
        if ((arq->options & eAdmissionRequest_destCallSignalAddress) &&
            get_h225_addr(ct, *data, &arq->destCallSignalAddress,
                          &addr, &port) &&
            !memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) &&
            port == info->sig_port[dir] &&
            set_h225_addr && ct->status & IPS_NAT_MASK) {
                /* Answering ARQ */
                return set_h225_addr(skb, data, 0,
                                     &arq->destCallSignalAddress,
                                     &ct->tuplehash[!dir].tuple.dst.u3,
                                     info->sig_port[!dir]);
        }

        if ((arq->options & eAdmissionRequest_srcCallSignalAddress) &&
            get_h225_addr(ct, *data, &arq->srcCallSignalAddress,
                          &addr, &port) &&
            !memcmp(&addr, &ct->tuplehash[dir].tuple.src.u3, sizeof(addr)) &&
            set_h225_addr && ct->status & IPS_NAT_MASK) {
                /* Calling ARQ */
                return set_h225_addr(skb, data, 0,
                                     &arq->srcCallSignalAddress,
                                     &ct->tuplehash[!dir].tuple.dst.u3,
                                     port);
        }

        return 0;
}

/****************************************************************************/
static int process_acf(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, AdmissionConfirm *acf)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;
        typeof(set_sig_addr_hook) set_sig_addr;

        pr_debug("nf_ct_ras: ACF\n");

        if (!get_h225_addr(ct, *data, &acf->destCallSignalAddress,
                           &addr, &port))
                return 0;

        if (!memcmp(&addr, &ct->tuplehash[dir].tuple.dst.u3, sizeof(addr))) {
                /* Answering ACF */
                set_sig_addr = rcu_dereference(set_sig_addr_hook);
                if (set_sig_addr && ct->status & IPS_NAT_MASK)
                        return set_sig_addr(skb, ct, ctinfo, data,
                                            &acf->destCallSignalAddress, 1);
                return 0;
        }

        /* Need new expect */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3, &addr,
                          IPPROTO_TCP, NULL, &port);
        exp->flags = NF_CT_EXPECT_PERMANENT;
        exp->helper = nf_conntrack_helper_q931;

        if (nf_ct_expect_related(exp) == 0) {
                pr_debug("nf_ct_ras: expect Q.931 ");
                nf_ct_dump_tuple(&exp->tuple);
        } else
                ret = -1;

        nf_ct_expect_put(exp);

        return ret;
}

/****************************************************************************/
static int process_lrq(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, LocationRequest *lrq)
{
        typeof(set_ras_addr_hook) set_ras_addr;

        pr_debug("nf_ct_ras: LRQ\n");

        set_ras_addr = rcu_dereference(set_ras_addr_hook);
        if (set_ras_addr && ct->status & IPS_NAT_MASK)
                return set_ras_addr(skb, ct, ctinfo, data,
                                    &lrq->replyAddress, 1);
        return 0;
}

/****************************************************************************/
static int process_lcf(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, LocationConfirm *lcf)
{
        int dir = CTINFO2DIR(ctinfo);
        int ret = 0;
        __be16 port;
        union nf_inet_addr addr;
        struct nf_conntrack_expect *exp;

        pr_debug("nf_ct_ras: LCF\n");

        if (!get_h225_addr(ct, *data, &lcf->callSignalAddress,
                           &addr, &port))
                return 0;

        /* Need new expect for call signal */
        if ((exp = nf_ct_expect_alloc(ct)) == NULL)
                return -1;
        nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct),
                          &ct->tuplehash[!dir].tuple.src.u3, &addr,
                          IPPROTO_TCP, NULL, &port);
        exp->flags = NF_CT_EXPECT_PERMANENT;
        exp->helper = nf_conntrack_helper_q931;

        if (nf_ct_expect_related(exp) == 0) {
                pr_debug("nf_ct_ras: expect Q.931 ");
                nf_ct_dump_tuple(&exp->tuple);
        } else
                ret = -1;

        nf_ct_expect_put(exp);

        /* Ignore rasAddress */

        return ret;
}

/****************************************************************************/
static int process_irr(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, InfoRequestResponse *irr)
{
        int ret;
        typeof(set_ras_addr_hook) set_ras_addr;
        typeof(set_sig_addr_hook) set_sig_addr;

        pr_debug("nf_ct_ras: IRR\n");

        set_ras_addr = rcu_dereference(set_ras_addr_hook);
        if (set_ras_addr && ct->status & IPS_NAT_MASK) {
                ret = set_ras_addr(skb, ct, ctinfo, data,
                                   &irr->rasAddress, 1);
                if (ret < 0)
                        return -1;
        }

        set_sig_addr = rcu_dereference(set_sig_addr_hook);
        if (set_sig_addr && ct->status & IPS_NAT_MASK) {
                ret = set_sig_addr(skb, ct, ctinfo, data,
                                        irr->callSignalAddress.item,
                                        irr->callSignalAddress.count);
                if (ret < 0)
                        return -1;
        }

        return 0;
}

/****************************************************************************/
static int process_ras(struct sk_buff *skb, struct nf_conn *ct,
                       enum ip_conntrack_info ctinfo,
                       unsigned char **data, RasMessage *ras)
{
        switch (ras->choice) {
        case eRasMessage_gatekeeperRequest:
                return process_grq(skb, ct, ctinfo, data,
                                   &ras->gatekeeperRequest);
        case eRasMessage_gatekeeperConfirm:
                return process_gcf(skb, ct, ctinfo, data,
                                   &ras->gatekeeperConfirm);
        case eRasMessage_registrationRequest:
                return process_rrq(skb, ct, ctinfo, data,
                                   &ras->registrationRequest);
        case eRasMessage_registrationConfirm:
                return process_rcf(skb, ct, ctinfo, data,
                                   &ras->registrationConfirm);
        case eRasMessage_unregistrationRequest:
                return process_urq(skb, ct, ctinfo, data,
                                   &ras->unregistrationRequest);
        case eRasMessage_admissionRequest:
                return process_arq(skb, ct, ctinfo, data,
                                   &ras->admissionRequest);
        case eRasMessage_admissionConfirm:
                return process_acf(skb, ct, ctinfo, data,
                                   &ras->admissionConfirm);
        case eRasMessage_locationRequest:
                return process_lrq(skb, ct, ctinfo, data,
                                   &ras->locationRequest);
        case eRasMessage_locationConfirm:
                return process_lcf(skb, ct, ctinfo, data,
                                   &ras->locationConfirm);
        case eRasMessage_infoRequestResponse:
                return process_irr(skb, ct, ctinfo, data,
                                   &ras->infoRequestResponse);
        default:
                pr_debug("nf_ct_ras: RAS message %d\n", ras->choice);
                break;
        }

        return 0;
}

/****************************************************************************/
static int ras_help(struct sk_buff *skb, unsigned int protoff,
                    struct nf_conn *ct, enum ip_conntrack_info ctinfo)
{
        static RasMessage ras;
        unsigned char *data;
        int datalen = 0;
        int ret;

        pr_debug("nf_ct_ras: skblen = %u\n", skb->len);

        spin_lock_bh(&nf_h323_lock);

        /* Get UDP data */
        data = get_udp_data(skb, protoff, &datalen);
        if (data == NULL)
                goto accept;
        pr_debug("nf_ct_ras: RAS message len=%d ", datalen);
        nf_ct_dump_tuple(&ct->tuplehash[CTINFO2DIR(ctinfo)].tuple);

        /* Decode RAS message */
        ret = DecodeRasMessage(data, datalen, &ras);
        if (ret < 0) {
                pr_debug("nf_ct_ras: decoding error: %s\n",
                         ret == H323_ERROR_BOUND ?
                         "out of bound" : "out of range");
                goto accept;
        }

        /* Process RAS message */
        if (process_ras(skb, ct, ctinfo, &data, &ras) < 0)
                goto drop;

      accept:
        spin_unlock_bh(&nf_h323_lock);
        return NF_ACCEPT;

      drop:
        spin_unlock_bh(&nf_h323_lock);
        if (net_ratelimit())
                printk("nf_ct_ras: packet dropped\n");
        return NF_DROP;
}

/****************************************************************************/
static const struct nf_conntrack_expect_policy ras_exp_policy = {
        .max_expected           = 32,
        .timeout                = 240,
};

static struct nf_conntrack_helper nf_conntrack_helper_ras[] __read_mostly = {
        {
                .name                   = "RAS",
                .me                     = THIS_MODULE,
                .tuple.src.l3num        = AF_INET,
                .tuple.src.u.udp.port   = __constant_htons(RAS_PORT),
                .tuple.dst.protonum     = IPPROTO_UDP,
                .help                   = ras_help,
                .expect_policy          = &ras_exp_policy,
        },
        {
                .name                   = "RAS",
                .me                     = THIS_MODULE,
                .tuple.src.l3num        = AF_INET6,
                .tuple.src.u.udp.port   = __constant_htons(RAS_PORT),
                .tuple.dst.protonum     = IPPROTO_UDP,
                .help                   = ras_help,
                .expect_policy          = &ras_exp_policy,
        },
};

/****************************************************************************/
static void __exit nf_conntrack_h323_fini(void)
{
        nf_conntrack_helper_unregister(&nf_conntrack_helper_ras[1]);
        nf_conntrack_helper_unregister(&nf_conntrack_helper_ras[0]);
        nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[1]);
        nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[0]);
        nf_conntrack_helper_unregister(&nf_conntrack_helper_h245);
        kfree(h323_buffer);
        pr_debug("nf_ct_h323: fini\n");
}

/****************************************************************************/
static int __init nf_conntrack_h323_init(void)
{
        int ret;

        h323_buffer = kmalloc(65536, GFP_KERNEL);
        if (!h323_buffer)
                return -ENOMEM;
        ret = nf_conntrack_helper_register(&nf_conntrack_helper_h245);
        if (ret < 0)
                goto err1;
        ret = nf_conntrack_helper_register(&nf_conntrack_helper_q931[0]);
        if (ret < 0)
                goto err2;
        ret = nf_conntrack_helper_register(&nf_conntrack_helper_q931[1]);
        if (ret < 0)
                goto err3;
        ret = nf_conntrack_helper_register(&nf_conntrack_helper_ras[0]);
        if (ret < 0)
                goto err4;
        ret = nf_conntrack_helper_register(&nf_conntrack_helper_ras[1]);
        if (ret < 0)
                goto err5;
        pr_debug("nf_ct_h323: init success\n");
        return 0;

err5:
        nf_conntrack_helper_unregister(&nf_conntrack_helper_ras[0]);
err4:
        nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[1]);
err3:
        nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[0]);
err2:
        nf_conntrack_helper_unregister(&nf_conntrack_helper_h245);
err1:
        kfree(h323_buffer);
        return ret;
}

/****************************************************************************/
module_init(nf_conntrack_h323_init);
module_exit(nf_conntrack_h323_fini);

EXPORT_SYMBOL_GPL(get_h225_addr);
EXPORT_SYMBOL_GPL(set_h245_addr_hook);
EXPORT_SYMBOL_GPL(set_h225_addr_hook);
EXPORT_SYMBOL_GPL(set_sig_addr_hook);
EXPORT_SYMBOL_GPL(set_ras_addr_hook);
EXPORT_SYMBOL_GPL(nat_rtp_rtcp_hook);
EXPORT_SYMBOL_GPL(nat_t120_hook);
EXPORT_SYMBOL_GPL(nat_h245_hook);
EXPORT_SYMBOL_GPL(nat_callforwarding_hook);
EXPORT_SYMBOL_GPL(nat_q931_hook);

MODULE_AUTHOR("Jing Min Zhao <zhaojingmin@users.sourceforge.net>");
MODULE_DESCRIPTION("H.323 connection tracking helper");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip_conntrack_h323");

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