nf_conntrack_h323_main.c

linux 内核源代码

		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 <[e-mail]>");
MODULE_DESCRIPTION("H.323 connection tracking helper");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ip_conntrack_h323");