socket.c

 *
 * 7.1.1 SCTP_RTOINFO
 *
 * The protocol parameters used to initialize and bound retransmission
 * timeout (RTO) are tunable. sctp_rtoinfo structure is used to access
 * and modify these parameters.
 * All parameters are time values, in milliseconds.  A value of 0, when
 * modifying the parameters, indicates that the current value should not
 * be changed.
 *
 */
static int sctp_getsockopt_rtoinfo(struct sock *sk, int len,
				char __user *optval,
				int __user *optlen) {
	struct sctp_rtoinfo rtoinfo;
	struct sctp_association *asoc;

	if (len < sizeof (struct sctp_rtoinfo))
		return -EINVAL;

	len = sizeof(struct sctp_rtoinfo);

	if (copy_from_user(&rtoinfo, optval, len))
		return -EFAULT;

	asoc = sctp_id2assoc(sk, rtoinfo.srto_assoc_id);

	if (!asoc && rtoinfo.srto_assoc_id && sctp_style(sk, UDP))
		return -EINVAL;

	/* Values corresponding to the specific association. */
	if (asoc) {
		rtoinfo.srto_initial = jiffies_to_msecs(asoc->rto_initial);
		rtoinfo.srto_max = jiffies_to_msecs(asoc->rto_max);
		rtoinfo.srto_min = jiffies_to_msecs(asoc->rto_min);
	} else {
		/* Values corresponding to the endpoint. */
		struct sctp_sock *sp = sctp_sk(sk);

		rtoinfo.srto_initial = sp->rtoinfo.srto_initial;
		rtoinfo.srto_max = sp->rtoinfo.srto_max;
		rtoinfo.srto_min = sp->rtoinfo.srto_min;
	}

	if (put_user(len, optlen))
		return -EFAULT;

	if (copy_to_user(optval, &rtoinfo, len))
		return -EFAULT;

	return 0;
}

/*
 *
 * 7.1.2 SCTP_ASSOCINFO
 *
 * This option is used to tune the maximum retransmission attempts
 * of the association.
 * Returns an error if the new association retransmission value is
 * greater than the sum of the retransmission value  of the peer.
 * See [SCTP] for more information.
 *
 */
static int sctp_getsockopt_associnfo(struct sock *sk, int len,
				     char __user *optval,
				     int __user *optlen)
{

	struct sctp_assocparams assocparams;
	struct sctp_association *asoc;
	struct list_head *pos;
	int cnt = 0;

	if (len < sizeof (struct sctp_assocparams))
		return -EINVAL;

	len = sizeof(struct sctp_assocparams);

	if (copy_from_user(&assocparams, optval, len))
		return -EFAULT;

	asoc = sctp_id2assoc(sk, assocparams.sasoc_assoc_id);

	if (!asoc && assocparams.sasoc_assoc_id && sctp_style(sk, UDP))
		return -EINVAL;

	/* Values correspoinding to the specific association */
	if (asoc) {
		assocparams.sasoc_asocmaxrxt = asoc->max_retrans;
		assocparams.sasoc_peer_rwnd = asoc->peer.rwnd;
		assocparams.sasoc_local_rwnd = asoc->a_rwnd;
		assocparams.sasoc_cookie_life = (asoc->cookie_life.tv_sec
						* 1000) +
						(asoc->cookie_life.tv_usec
						/ 1000);

		list_for_each(pos, &asoc->peer.transport_addr_list) {
			cnt ++;
		}

		assocparams.sasoc_number_peer_destinations = cnt;
	} else {
		/* Values corresponding to the endpoint */
		struct sctp_sock *sp = sctp_sk(sk);

		assocparams.sasoc_asocmaxrxt = sp->assocparams.sasoc_asocmaxrxt;
		assocparams.sasoc_peer_rwnd = sp->assocparams.sasoc_peer_rwnd;
		assocparams.sasoc_local_rwnd = sp->assocparams.sasoc_local_rwnd;
		assocparams.sasoc_cookie_life =
					sp->assocparams.sasoc_cookie_life;
		assocparams.sasoc_number_peer_destinations =
					sp->assocparams.
					sasoc_number_peer_destinations;
	}

	if (put_user(len, optlen))
		return -EFAULT;

	if (copy_to_user(optval, &assocparams, len))
		return -EFAULT;

	return 0;
}

/*
 * 7.1.16 Set/clear IPv4 mapped addresses (SCTP_I_WANT_MAPPED_V4_ADDR)
 *
 * This socket option is a boolean flag which turns on or off mapped V4
 * addresses.  If this option is turned on and the socket is type
 * PF_INET6, then IPv4 addresses will be mapped to V6 representation.
 * If this option is turned off, then no mapping will be done of V4
 * addresses and a user will receive both PF_INET6 and PF_INET type
 * addresses on the socket.
 */
static int sctp_getsockopt_mappedv4(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	int val;
	struct sctp_sock *sp = sctp_sk(sk);

	if (len < sizeof(int))
		return -EINVAL;

	len = sizeof(int);
	val = sp->v4mapped;
	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;

	return 0;
}

/*
 * 7.1.29.  Set or Get the default context (SCTP_CONTEXT)
 * (chapter and verse is quoted at sctp_setsockopt_context())
 */
static int sctp_getsockopt_context(struct sock *sk, int len,
				   char __user *optval, int __user *optlen)
{
	struct sctp_assoc_value params;
	struct sctp_sock *sp;
	struct sctp_association *asoc;

	if (len < sizeof(struct sctp_assoc_value))
		return -EINVAL;

	len = sizeof(struct sctp_assoc_value);

	if (copy_from_user(&params, optval, len))
		return -EFAULT;

	sp = sctp_sk(sk);

	if (params.assoc_id != 0) {
		asoc = sctp_id2assoc(sk, params.assoc_id);
		if (!asoc)
			return -EINVAL;
		params.assoc_value = asoc->default_rcv_context;
	} else {
		params.assoc_value = sp->default_rcv_context;
	}

	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &params, len))
		return -EFAULT;

	return 0;
}

/*
 * 8.1.16.  Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG)
 * This option will get or set the maximum size to put in any outgoing
 * SCTP DATA chunk.  If a message is larger than this size it will be
 * fragmented by SCTP into the specified size.  Note that the underlying
 * SCTP implementation may fragment into smaller sized chunks when the
 * PMTU of the underlying association is smaller than the value set by
 * the user.  The default value for this option is '0' which indicates
 * the user is NOT limiting fragmentation and only the PMTU will effect
 * SCTP's choice of DATA chunk size.  Note also that values set larger
 * than the maximum size of an IP datagram will effectively let SCTP
 * control fragmentation (i.e. the same as setting this option to 0).
 *
 * The following structure is used to access and modify this parameter:
 *
 * struct sctp_assoc_value {
 *   sctp_assoc_t assoc_id;
 *   uint32_t assoc_value;
 * };
 *
 * assoc_id:  This parameter is ignored for one-to-one style sockets.
 *    For one-to-many style sockets this parameter indicates which
 *    association the user is performing an action upon.  Note that if
 *    this field's value is zero then the endpoints default value is
 *    changed (effecting future associations only).
 * assoc_value:  This parameter specifies the maximum size in bytes.
 */
static int sctp_getsockopt_maxseg(struct sock *sk, int len,
				  char __user *optval, int __user *optlen)
{
	struct sctp_assoc_value params;
	struct sctp_association *asoc;

	if (len == sizeof(int)) {
		printk(KERN_WARNING
		   "SCTP: Use of int in maxseg socket option deprecated\n");
		printk(KERN_WARNING
		   "SCTP: Use struct sctp_assoc_value instead\n");
		params.assoc_id = 0;
	} else if (len >= sizeof(struct sctp_assoc_value)) {
		len = sizeof(struct sctp_assoc_value);
		if (copy_from_user(&params, optval, sizeof(params)))
			return -EFAULT;
	} else
		return -EINVAL;

	asoc = sctp_id2assoc(sk, params.assoc_id);
	if (!asoc && params.assoc_id && sctp_style(sk, UDP))
		return -EINVAL;

	if (asoc)
		params.assoc_value = asoc->frag_point;
	else
		params.assoc_value = sctp_sk(sk)->user_frag;

	if (put_user(len, optlen))
		return -EFAULT;
	if (len == sizeof(int)) {
		if (copy_to_user(optval, &params.assoc_value, len))
			return -EFAULT;
	} else {
		if (copy_to_user(optval, &params, len))
			return -EFAULT;
	}

	return 0;
}

/*
 * 7.1.24.  Get or set fragmented interleave (SCTP_FRAGMENT_INTERLEAVE)
 * (chapter and verse is quoted at sctp_setsockopt_fragment_interleave())
 */
static int sctp_getsockopt_fragment_interleave(struct sock *sk, int len,
					       char __user *optval, int __user *optlen)
{
	int val;

	if (len < sizeof(int))
		return -EINVAL;

	len = sizeof(int);

	val = sctp_sk(sk)->frag_interleave;
	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;

	return 0;
}

/*
 * 7.1.25.  Set or Get the sctp partial delivery point
 * (chapter and verse is quoted at sctp_setsockopt_partial_delivery_point())
 */
static int sctp_getsockopt_partial_delivery_point(struct sock *sk, int len,
						  char __user *optval,
						  int __user *optlen)
{
	u32 val;

	if (len < sizeof(u32))
		return -EINVAL;

	len = sizeof(u32);

	val = sctp_sk(sk)->pd_point;
	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;

	return -ENOTSUPP;
}

/*
 * 7.1.28.  Set or Get the maximum burst (SCTP_MAX_BURST)
 * (chapter and verse is quoted at sctp_setsockopt_maxburst())
 */
static int sctp_getsockopt_maxburst(struct sock *sk, int len,
				    char __user *optval,
				    int __user *optlen)
{
	struct sctp_assoc_value params;
	struct sctp_sock *sp;
	struct sctp_association *asoc;

	if (len == sizeof(int)) {
		printk(KERN_WARNING
		   "SCTP: Use of int in max_burst socket option deprecated\n");
		printk(KERN_WARNING
		   "SCTP: Use struct sctp_assoc_value instead\n");
		params.assoc_id = 0;
	} else if (len >= sizeof(struct sctp_assoc_value)) {
		len = sizeof(struct sctp_assoc_value);
		if (copy_from_user(&params, optval, len))
			return -EFAULT;
	} else
		return -EINVAL;

	sp = sctp_sk(sk);

	if (params.assoc_id != 0) {
		asoc = sctp_id2assoc(sk, params.assoc_id);
		if (!asoc)
			return -EINVAL;
		params.assoc_value = asoc->max_burst;
	} else
		params.assoc_value = sp->max_burst;

	if (len == sizeof(int)) {
		if (copy_to_user(optval, &params.assoc_value, len))
			return -EFAULT;
	} else {
		if (copy_to_user(optval, &params, len))
			return -EFAULT;
	}

	return 0;

}

static int sctp_getsockopt_hmac_ident(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	struct sctp_hmacalgo  __user *p = (void __user *)optval;
	struct sctp_hmac_algo_param *hmacs;
	__u16 data_len = 0;
	u32 num_idents;

	if (!sctp_auth_enable)
		return -EACCES;

	hmacs = sctp_sk(sk)->ep->auth_hmacs_list;
	data_len = ntohs(hmacs->param_hdr.length) - sizeof(sctp_paramhdr_t);

	if (len < sizeof(struct sctp_hmacalgo) + data_len)
		return -EINVAL;

	len = sizeof(struct sctp_hmacalgo) + data_len;
	num_idents = data_len / sizeof(u16);

	if (put_user(len, optlen))
		return -EFAULT;
	if (put_user(num_idents, &p->shmac_num_idents))
		return -EFAULT;
	if (copy_to_user(p->shmac_idents, hmacs->hmac_ids, data_len))
		return -EFAULT;
	return 0;
}

static int sctp_getsockopt_active_key(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	struct sctp_authkeyid val;
	struct sctp_association *asoc;

	if (!sctp_auth_enable)
		return -EACCES;

	if (len < sizeof(struct sctp_authkeyid))
		return -EINVAL;
	if (copy_from_user(&val, optval, sizeof(struct sctp_authkeyid)))
		return -EFAULT;

	asoc = sctp_id2assoc(sk, val.scact_assoc_id);
	if (!asoc && val.scact_assoc_id && sctp_style(sk, UDP))
		return -EINVAL;

	if (asoc)
		val.scact_keynumber = asoc->active_key_id;
	else
		val.scact_keynumber = sctp_sk(sk)->ep->active_key_id;

	len = sizeof(struct sctp_authkeyid);
	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;

	return 0;
}

static int sctp_getsockopt_peer_auth_chunks(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	struct sctp_authchunks __user *p = (void __user *)optval;
	struct sctp_authchunks val;
	struct sctp_association *asoc;
	struct sctp_chunks_param *ch;
	u32    num_chunks = 0;
	char __user *to;

	if (!sctp_auth_enable)
		return -EACCES;

	if (len < sizeof(struct sctp_authchunks))
		return -EINVAL;

	if (copy_from_user(&val, optval, sizeof(struct sctp_authchunks)))
		return -EFAULT;

	to = p->gauth_chunks;
	asoc = sctp_id2assoc(sk, val.gauth_assoc_id);
	if (!asoc)
		return -EINVAL;

	ch = asoc->peer.peer_chunks;
	if (!ch)
		goto num;

	/* See if the user provided enough room for all the data */
	num_chunks = ntohs(ch->param_hdr.length) - sizeof(sctp_paramhdr_t);
	if (len < num_chunks)
		return -EINVAL;

	if (copy_to_user(to, ch->chunks, num_chunks))
		return -EFAULT;
num:
	len = sizeof(struct sctp_authchunks) + num_chunks;
	if (put_user(len, optlen)) return -EFAULT;
	if (put_user(num_chunks, &p->gauth_number_of_chunks))
		return -EFAULT;
	return 0;
}

static int sctp_getsockopt_local_auth_chunks(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	struct sctp_authchunks __user *p = (void __user *)optval;
	struct sctp_authchunks val;
	struct sctp_association *asoc;
	struct sctp_chunks_param *ch;
	u32    num_chunks = 0;
	char __user *to;

	if (!sctp_auth_enable)
		return -EACCES;

	if (len < sizeof(struct sctp_authchunks))
		return -EINVAL;

	if (copy_from_user(&val, optval, sizeof(struct sctp_authchunks)))
		return -EFAULT;

	to = p->gauth_chunks;
	asoc = sctp_id2assoc(sk, val.gauth_assoc_id);
	if (!asoc && val.gauth_assoc_id && sctp_style(sk, UDP))
		return -EINVAL;

	if (asoc)
		ch = (struct sctp_chunks_param*)asoc->c.auth_chunks;
	else
		ch = sctp_sk(sk)->ep->auth_chunk_list;

	if (!ch)
		goto num;

	num_chunks = ntohs(ch->param_hdr.length) - sizeof(sctp_paramhdr_t);
	if (len < sizeof(struct sctp_authchunks) + num_chunks)
		return -EINVAL;

	if (copy_to_user(to, ch->chunks, num_chunks))
		return -EFAULT;
num:
	len = sizeof(struct sctp_authchunks) + num_chunks;
	if (put_user(len, optlen))
		return -EFAULT;
	if (put_user(num_chunks, &p->gauth_number_of_chunks))
		return -EFAULT;

	return 0;
}

/*
 * 8.2.5.  Get the Current Number of Associations (SCTP_GET_ASSOC_NUMBER)
 * This option gets the current number of associations that are attached
 * to a one-to-many style socket.  The option value is an uint32_t.
 */
static int sctp_getsockopt_assoc_number(struct sock *sk, int len,
				    char __user *optval, int __user *optlen)
{
	struct sctp_sock *sp = sctp_sk(sk);
	struct sctp_association *asoc;
	u32 val = 0;

	if (sctp_style(sk, TCP))
		return -EOPNOTSUPP;

	if (len < sizeof(u32))
		return -EINVAL;

	len = sizeof(u32);

	list_for_each_entry(asoc, &(sp->ep->asocs), asocs) {
		val++;
	}

	if (put_user(len, optlen))
		return -EFAULT;
	if (copy_to_user(optval, &val, len))
		return -EFAULT;

	return 0;
}

SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
				char __user *optval, int __user *optlen)
{
	int retval = 0;
	int len;

	SCTP_DEBUG_PRINTK("sctp_getsockopt(sk: %p... optname: %d)\n",
			  sk, optname);

	/* I can hardly begin to describe how wrong this is.  This is
	 * so broken as to be worse than useless.  The API draft
	 * REALLY is NOT helpful here...  I am not convinced that the
	 * semantics of getsockopt() with a level OTHER THAN SOL_SCTP
	 * are at all well-founded.
	 */
	if (level != SOL_SCTP) {
		struct sctp_af *af = sctp_sk(sk)->pf->af;

		retval = af->getsockopt(sk, level, optname, optval, optlen);
		return retval;
	}

	if (get_user(len, optlen))
		return -EFAULT;

	sctp_lock_sock(sk);

	switch (optname) {
	case SCTP_STATUS:
		retval = sctp_getsockopt_sctp_status(sk, len, optval, optlen);
		break;
	case SCTP_DISABLE_FRAGMENTS:
		retval = sctp_getsockopt_disable_fragments(sk, len, optval,
							   optlen);
		break;
	case SCTP_EVENTS:
		retval = sctp_getsockopt_events(sk, len, optval, optlen);
		break;
	case SCTP_AUTOCLOSE:
		retval = sctp_getsockopt_autoclose(sk, len, optval, optlen);
		break;
	case SCTP_SOCKOPT_PEELOFF:
		retval = sctp_getsockopt_peeloff(sk, len, optval, optlen);
		break;
	case SCTP_PEER_ADDR_PARAMS:
		retval = sctp_getsockopt_peer_addr_params(sk, len, optval,
							  optlen);
		break;
	case SCTP_DELAYED_ACK:
		retval = sctp_getsockopt_delayed_ack(sk, len, optval,
							  optlen);
		break;
	case SCTP_INITMSG:
		retval = sctp_getsockopt_initmsg(sk, len, optval, optlen);
		break;
	case SCTP_GET_PEER_ADDRS_NUM_OLD:
		retval = sctp_getsockopt_peer_addrs_num_old(sk, len, optval,
							    optlen);
		break;
	case SCTP_GET_LOCAL_ADDRS_NUM_OLD:
		retval = sctp_getsockopt_local_addrs_num_old(sk, len, optval,
							     optlen);
		break;
	case SCTP_GET_PEER_ADDRS_OLD:
		retval = sctp_getsockopt_peer_addrs_old(sk, len, optval,
							optlen);
		break;
	case SCTP_GET_LOCAL_ADDRS_OLD:
		retval = sctp_getsockopt_local_addrs_old(sk, len, optval,
							 optlen);
		break;
	case SCTP_GET_PEER_ADDRS:
		retval = sctp_getsockopt_peer_addrs(sk, len, optval,
						    optlen);
		break;
	case SCTP_GET_LOCAL_ADDRS:
		retval = sctp_getsockopt_local_addrs(sk, len, optval,
						     optlen);
		break;
	case SCTP_SOCKOPT_CONNECTX3:
		retval = sctp_getsockopt_connectx3(sk, len, optval, optlen);
		break;
	case SCTP_DEFAULT_SEND_PARAM:
		retval = sctp_getsockopt_default_send_param(sk, len,
							    optval, optlen);
		break;
	case SCTP_PRIMARY_ADDR:
		retval = sctp_getsockopt_primary_addr(sk, len, optval, optlen);
		break;
	case SCTP_NODELAY:
		retval = sctp_getsockopt_nodelay(sk, len, optval, optlen);
		break;
	case SCTP_RTOINFO:
		retval = sctp_getsockopt_rtoinfo(sk, len, optval, optlen);
		break;
	case SCTP_ASSOCINFO:
		retval = sctp_getsockopt_associnfo(sk, len, optval, optlen);
		break;
	case SCTP_I_WANT_MAPPED_V4_ADDR:
		retval = sctp_getsockopt_mappedv4(sk, len, optval, optlen);
		break;
	case SCTP_MAXSEG:
		retval = sctp_getsockopt_maxseg(sk, len, optval, optlen);
		break;
	case SCTP_GET_PEER_ADDR_INFO:
		retval = sctp_getsockopt_peer_addr_info(sk, len, optval,
							optlen);
		break;
	case SCTP_ADAPTATION_LAYER:
		retval = sctp_getsockopt_adaptation_layer(sk, len, optval,
							optlen);
		break;
	case SCTP_CONTEXT:
		retval = sctp_getsockopt_context(sk, len, optval, optlen);
		break;
	case SCTP_FRAGMENT_INTERLEAVE:
		retval = sctp_getsockopt_fragment_interleave(sk, len, optval,
							     optlen);
		break;
	case SCTP_PARTIAL_DELIVERY_POINT:
		retval = sctp_getsockopt_partial_delivery_point(sk, len, optval,
								optlen);
		break;
	case SCTP_MAX_BURST:
		retval = sctp_getsockopt_maxburst(sk, len, optval, optlen);
		break;
	case SCTP_AUTH_KEY:
	case SCTP_AUTH_CHUNK:
	case SCTP_AUTH_DELETE_KEY:
		retval = -EOPNOTSUPP;
		break;
	case SCTP_HMAC_IDENT:
		retval = sctp_getsockopt_hmac_ident(sk, len, optval, optlen);
		break;
	case SCTP_AUTH_ACTIVE_KEY:
		retval = sctp_getsockopt_active_key(sk, len, optval, optlen);
		break;
	case SCTP_PEER_AUTH_CHUNKS:
		retval = sctp_getsockopt_peer_auth_chunks(sk, len, optval,
							optlen);
		break;
	case SCTP_LOCAL_AUTH_CHUNKS:
		retval = sctp_getsockopt_local_auth_chunks(sk, len, optval,
							optlen);
		break;
	case SCTP_GET_ASSOC_NUMBER:
		retval = sctp_getsockopt_assoc_number(sk, len, optval, optlen);
		break;
	default:
		retval = -ENOPROTOOPT;
		break;
	}

	sctp_release_sock(sk);
	return retval;
}

static void sctp_hash(struct sock *sk)
{
	/* STUB */
}

static void sctp_unhash(struct sock *sk)
{
	/* STUB */
}

/* Check if port is acceptable.  Possibly find first available port.
 *
 * The port hash table (contained in the 'global' SCTP protocol storage
 * returned by struct sctp_protocol *sctp_get_protocol()). The hash
 * table is an array of 4096 lists (sctp_bind_hashbucket). Each
 * list (the list number is the port number hashed out, so as you
 * would expect from a hash function, all the ports in a given list have
 * such a number that hashes out to the same list number; you were
 * expecting that, right?); so each list has a set of ports, with a
 * link to the socket (struct sock) that uses it, the port number and
 * a fastreuse flag (FIXME: NPI ipg).
 */
static struct sctp_bind_bucket *sctp_bucket_create(
	struct sctp_bind_hashbucket *head, unsigned short snum);

static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
{
	struct sctp_bind_hashbucket *head; /* hash list */
	struct sctp_bind_bucket *pp; /* hash list port iterator */
	struct hlist_node *node;
	unsigned short snum;
	int ret;

	snum = ntohs(addr->v4.sin_port);

	SCTP_DEBUG_PRINTK("sctp_get_port() begins, snum=%d\n", snum);
	sctp_local_bh_disable();

	if (snum == 0) {
		/* Search for an available port. */
		int low, high, remaining, index;
		unsigned int rover;

		inet_get_local_port_range(&low, &high);
		remaining = (high - low) + 1;
		rover = net_random() % remaining + low;

		do {
			rover++;
			if ((rover < low) || (rover > high))
				rover = low;
			index = sctp_phashfn(rover);
			head = &sctp_port_hashtable[index];
			sctp_spin_lock(&head->lock);
			sctp_for_each_hentry(pp, node, &head->chain)
				if (pp->port == rover)
					goto next;
			break;
		next:
			sctp_spin_unlock(&head->lock);
		} while (--remaining > 0);

		/* Exhausted local port range during search? */
		ret = 1;
		if (remaining <= 0)
			goto fail;

		/* OK, here is the one we will use.  HEAD (the port
		 * hash table list entry) is non-NULL and we hold it's
		 * mutex.
		 */
		snum = rover;
	} else {
		/* We are given an specific port number; we verify
		 * that it is not being used. If it is used, we will
		 * exahust the search in the hash list corresponding
		 * to the port number (snum) - we detect that with the
		 * port iterator, pp being NULL.
		 */
		head = &sctp_port_hashtable[sctp_phashfn(snum)];
		sctp_spin_lock(&head->lock);
		sctp_for_each_hentry(pp, node, &head->chain) {
			if (pp->port == snum)
				goto pp_found;
		}
	}
	pp = NULL;
	goto pp_not_found;
pp_found:
	if (!hlist_empty(&pp->owner)) {
		/* We had a port hash table hit - there is an
		 * available port (pp != NULL) and it is being
		 * used by other socket (pp->owner not empty); that other
		 * socket is going to be sk2.
		 */
		int reuse = sk->sk_reuse;
		struct sock *sk2;
		struct hlist_node *node;

		SCTP_DEBUG_PRINTK("sctp_get_port() found a possible match\n");
		if (pp->fastreuse && sk->sk_reuse &&
			sk->sk_state != SCTP_SS_LISTENING)
			goto success;

		/* Run through the list of sockets bound to the port
		 * (pp->port) [via the pointers bind_next and
		 * bind_pprev in the struct sock *sk2 (pp->sk)]. On each one,
		 * we get the endpoint they describe and run through
		 * the endpoint's list of IP (v4 or v6) addresses,
		 * comparing each of the addresses with the address of
		 * the socket sk. If we find a match, then that means
		 * that this port/socket (sk) combination are already
		 * in an endpoint.
		 */
		sk_for_each_bound(sk2, node, &pp->owner) {
			struct sctp_endpoint *ep2;
			ep2 = sctp_sk(sk2)->ep;

			if (sk == sk2 ||
			    (reuse && sk2->sk_reuse &&
			     sk2->sk_state != SCTP_SS_LISTENING))
				continue;

			if (sctp_bind_addr_conflict(&ep2->base.bind_addr, addr,
						 sctp_sk(sk2), sctp_sk(sk))) {
				ret = (long)sk2;
				goto fail_unlock;
			}
		}
		SCTP_DEBUG_PRINTK("sctp_get_port(): Found a match\n");
	}
pp_not_found:
	/* If there was a hash table miss, create a new port.  */
	ret = 1;
	if (!pp && !(pp = sctp_bucket_create(head, snum)))
		goto fail_unlock;

	/* In either case (hit or miss), make sure fastreuse is 1 only
	 * if sk->sk_reuse is too (that is, if the caller requested
	 * SO_REUSEADDR on this socket -sk-).
	 */
	if (hlist_empty(&pp->owner)) {
		if (sk->sk_reuse && sk->sk_state != SCTP_SS_LISTENING)
			pp->fastreuse = 1;
		else
			pp->fastreuse = 0;
	} else if (pp->fastreuse &&
		(!sk->sk_reuse || sk->sk_state == SCTP_SS_LISTENING))
		pp->fastreuse = 0;

	/* We are set, so fill up all the data in the hash table
	 * entry, tie the socket list information with the rest of the
	 * sockets FIXME: Blurry, NPI (ipg).
	 */
success:
	if (!sctp_sk(sk)->bind_hash) {
		inet_sk(sk)->num = snum;
		sk_add_bind_node(sk, &pp->owner);
		sctp_sk(sk)->bind_hash = pp;
	}
	ret = 0;

fail_unlock:
	sctp_spin_unlock(&head->lock);

fail:
	sctp_local_bh_enable();
	return ret;
}

/* Assign a 'snum' port to the socket.  If snum == 0, an ephemeral
 * port is requested.
 */
static int sctp_get_port(struct sock *sk, unsigned short snum)
{
	long ret;
	union sctp_addr addr;
	struct sctp_af *af = sctp_sk(sk)->pf->af;

	/* Set up a dummy address struct from the sk. */
	af->from_sk(&addr, sk);
	addr.v4.sin_port = htons(snum);

	/* Note: sk->sk_num gets filled in if ephemeral port request. */
	ret = sctp_get_port_local(sk, &addr);

	return (ret ? 1 : 0);
}

/*
 *  Move a socket to LISTENING state.
 */
SCTP_STATIC int sctp_listen_start(struct sock *sk, int backlog)
{
	struct sctp_sock *sp = sctp_sk(sk);
	struct sctp_endpoint *ep = sp->ep;
	struct crypto_hash *tfm = NULL;

	/* Allocate HMAC for generating cookie. */
	if (!sctp_sk(sk)->hmac && sctp_hmac_alg) {
		tfm = crypto_alloc_hash(sctp_hmac_alg, 0, CRYPTO_ALG_ASYNC);
		if (IS_ERR(tfm)) {
			if (net_ratelimit()) {
				printk(KERN_INFO
				       "SCTP: failed to load transform for %s: %ld\n",
					sctp_hmac_alg, PTR_ERR(tfm));
			}
			return -ENOSYS;
		}
		sctp_sk(sk)->hmac = tfm;
	}

	/*
	 * If a bind() or sctp_bindx() is not called prior to a listen()
	 * call that allows new associations to be accepted, the system
	 * picks an ephemeral port and will choose an address set equivalent
	 * to binding with a wildcard address.
	 *
	 * This is not currently spelled out in the SCTP sockets
	 * extensions draft, but follows the practice as seen in TCP
	 * sockets.
	 *
	 */
	sk->sk_state = SCTP_SS_LISTENING;
	if (!ep->base.bind_addr.port) {
		if (sctp_autobind(sk))
			return -EAGAIN;
	} else {
		if (sctp_get_port(sk, inet_sk(sk)->num)) {
			sk->sk_state = SCTP_SS_CLOSED;
			return -EADDRINUSE;
		}
	}

	sk->sk_max_ack_backlog = backlog;
	sctp_hash_endpoint(ep);
	return 0;
}

/*
 * 4.1.3 / 5.1.3 listen()
 *
 *   By default, new associations are not accepted for UDP style sockets.
 *   An application uses listen() to mark a socket as being able to
 *   accept new associations.
 *
 *   On TCP style sockets, applications use listen() to ready the SCTP
 *   endpoint for accepting inbound associations.
 *
 *   On both types of endpoints a backlog of '0' disables listening.
 *
 *  Move a socket to LISTENING state.
 */
int sctp_inet_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;
	struct sctp_endpoint *ep = sctp_sk(sk)->ep;
	int err = -EINVAL;

	if (unlikely(backlog < 0))
		return err;

	sctp_lock_sock(sk);

	/* Peeled-off sockets are not allowed to listen().  */
	if (sctp_style(sk, UDP_HIGH_BANDWIDTH))
		goto out;

	if (sock->state != SS_UNCONNECTED)
		goto out;

	/* If backlog is zero, disable listening. */
	if (!backlog) {
		if (sctp_sstate(sk, CLOSED))
			goto out;

		err = 0;
		sctp_unhash_endpoint(ep);
		sk->sk_state = SCTP_SS_CLOSED;
		if (sk->sk_reuse)
			sctp_sk(sk)->bind_hash->fastreuse = 1;
		goto out;
	}

	/* If we are already listening, just update the backlog */
	if (sctp_sstate(sk, LISTENING))
		sk->sk_max_ack_backlog = backlog;
	else {
		err = sctp_listen_start(sk, backlog);
		if (err)
			goto out;
	}

	err = 0;
out:
	sctp_release_sock(sk);
	return err;
}

/*
 * This function is done by modeling the current datagram_poll() and the
 * tcp_poll().  Note that, based on these implementations, we don't
 * lock the socket in this function, even though it seems that,
 * ideally, locking or some other mechanisms can be used to ensure
 * the integrity of the counters (sndbuf and wmem_alloc) used