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nf_conntrack_h323_main.c

/*
 * 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_conntrack_address *addr, __be16 port)
                     __read_mostly;
int (*set_h225_addr_hook) (struct sk_buff *skb,
                     unsigned char **data, int dataoff,
                     TransportAddress *taddr,
                     union nf_conntrack_address *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);
      struct tcphdr _tcph, *th;
      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, unsigned char *data,
                   H245_TransportAddress *taddr,
                   union nf_conntrack_address *addr, __be16 *port)
{
      unsigned char *p;
      int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
      int len;

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

      switch (taddr->unicastAddress.choice) {
      case eUnicastAddress_iPAddress:
            if (family != AF_INET)
                  return 0;
            p = data + taddr->unicastAddress.iPAddress.network;
            len = 4;
            break;
      case eUnicastAddress_iP6Address:
            if (family != 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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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 struct nf_conntrack_helper nf_conntrack_helper_h245 __read_mostly = {
      .name             = "H.245",
      .me               = THIS_MODULE,
      .max_expected           = H323_RTP_CHANNEL_MAX * 4 + 2 /* T.120 */,
      .timeout          = 240,
      .tuple.dst.protonum     = IPPROTO_UDP,
      .help             = h245_help
};

/****************************************************************************/
int get_h225_addr(struct nf_conn *ct, unsigned char *data,
              TransportAddress *taddr,
              union nf_conntrack_address *addr, __be16 *port)
{
      unsigned char *p;
      int family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
      int len;

      switch (taddr->choice) {
      case eTransportAddress_ipAddress:
            if (family != AF_INET)
                  return 0;
            p = data + taddr->ipAddress.ip;
            len = 4;
            break;
      case eTransportAddress_ip6Address:
            if (family != 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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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(union nf_conntrack_address *src,
                         union nf_conntrack_address *dst,
                         int family)
{
      struct flowi fl1, fl2;
      int ret = 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 (ip_route_output_key(&rt1, &fl1) == 0) {
                  if (ip_route_output_key(&rt2, &fl2) == 0) {
                        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_IPV6) || defined(CONFIG_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));
            rt1 = (struct rt6_info *)ip6_route_output(NULL, &fl1);
            if (rt1) {
                  rt2 = (struct rt6_info *)ip6_route_output(NULL, &fl2);
                  if (rt2) {
                        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_conntrack_address 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,
                          ct->tuplehash[!dir].tuple.src.l3num)) {
            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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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_conntrack_address 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 struct nf_conntrack_helper nf_conntrack_helper_q931[] __read_mostly = {
      {
            .name             = "Q.931",
            .me               = THIS_MODULE,
                                /* T.120 and H.245 */
            .max_expected           = H323_RTP_CHANNEL_MAX * 4 + 4,
            .timeout          = 240,
            .tuple.src.l3num  = AF_INET,
            .tuple.src.u.tcp.port   = __constant_htons(Q931_PORT),
            .tuple.dst.protonum     = IPPROTO_TCP,
            .help             = q931_help
      },
      {
            .name             = "Q.931",
            .me               = THIS_MODULE,
                                /* T.120 and H.245 */
            .max_expected           = H323_RTP_CHANNEL_MAX * 4 + 4,
            .timeout          = 240,
            .tuple.src.l3num  = AF_INET6,
            .tuple.src.u.tcp.port   = __constant_htons(Q931_PORT),
            .tuple.dst.protonum     = IPPROTO_TCP,
            .help             = q931_help
      },
};

/****************************************************************************/
static unsigned char *get_udp_data(struct sk_buff *skb, unsigned int protoff,
                           int *datalen)
{
      struct udphdr _uh, *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_conntrack_address *addr,
                                     __be16 port)
{
      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(&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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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 */
            read_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);
            }
            read_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)
{
      struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
      int dir = CTINFO2DIR(ctinfo);
      __be16 port;
      union nf_conntrack_address 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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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_conntrack_address 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, ct->tuplehash[!dir].tuple.src.l3num,
                    &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 struct nf_conntrack_helper nf_conntrack_helper_ras[] __read_mostly = {
      {
            .name             = "RAS",
            .me               = THIS_MODULE,
            .max_expected           = 32,
            .timeout          = 240,
            .tuple.src.l3num  = AF_INET,
            .tuple.src.u.udp.port   = __constant_htons(RAS_PORT),
            .tuple.dst.protonum     = IPPROTO_UDP,
            .help             = ras_help,
      },
      {
            .name             = "RAS",
            .me               = THIS_MODULE,
            .max_expected           = 32,
            .timeout          = 240,
            .tuple.src.l3num  = AF_INET6,
            .tuple.src.u.udp.port   = __constant_htons(RAS_PORT),
            .tuple.dst.protonum     = IPPROTO_UDP,
            .help             = ras_help,
      },
};

/****************************************************************************/
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]);
      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_q931[0]);
      if (ret < 0)
            goto err1;
      ret = nf_conntrack_helper_register(&nf_conntrack_helper_q931[1]);
      if (ret < 0)
            goto err2;
      ret = nf_conntrack_helper_register(&nf_conntrack_helper_ras[0]);
      if (ret < 0)
            goto err3;
      ret = nf_conntrack_helper_register(&nf_conntrack_helper_ras[1]);
      if (ret < 0)
            goto err4;
      pr_debug("nf_ct_h323: init success\n");
      return 0;

err4:
      nf_conntrack_helper_unregister(&nf_conntrack_helper_ras[0]);
err3:
      nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[1]);
err2:
      nf_conntrack_helper_unregister(&nf_conntrack_helper_q931[0]);
err1:
      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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