socket.c

		pr_warn_ratelimited(DEPRECATED
				    "%s (pid %d) "
				    "Use of int in maxseg socket option.\n"
				    "Use struct sctp_assoc_value instead\n",
				    current->comm, task_pid_nr(current));
		if (copy_from_user(&val, optval, optlen))
			return -EFAULT;
		params.assoc_id = 0;
	} else if (optlen == sizeof(struct sctp_assoc_value)) {
		if (copy_from_user(&params, optval, optlen))
			return -EFAULT;
		val = params.assoc_value;
	} else
		return -EINVAL;

	if ((val != 0) && ((val < 8) || (val > SCTP_MAX_CHUNK_LEN)))
		return -EINVAL;

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

	if (asoc) {
		if (val == 0) {
			val = asoc->pathmtu;
			val -= sp->pf->af->net_header_len;
			val -= sizeof(struct sctphdr) +
					sizeof(struct sctp_data_chunk);
		}
		asoc->user_frag = val;
		asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
	} else {
		sp->user_frag = val;
	}

	return 0;
}


/*
 *  7.1.9 Set Peer Primary Address (SCTP_SET_PEER_PRIMARY_ADDR)
 *
 *   Requests that the peer mark the enclosed address as the association
 *   primary. The enclosed address must be one of the association's
 *   locally bound addresses. The following structure is used to make a
 *   set primary request:
 */
static int sctp_setsockopt_peer_primary_addr(struct sock *sk, char __user *optval,
					     unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_sock	*sp;
	struct sctp_association	*asoc = NULL;
	struct sctp_setpeerprim	prim;
	struct sctp_chunk	*chunk;
	struct sctp_af		*af;
	int 			err;

	sp = sctp_sk(sk);

	if (!net->sctp.addip_enable)
		return -EPERM;

	if (optlen != sizeof(struct sctp_setpeerprim))
		return -EINVAL;

	if (copy_from_user(&prim, optval, optlen))
		return -EFAULT;

	asoc = sctp_id2assoc(sk, prim.sspp_assoc_id);
	if (!asoc)
		return -EINVAL;

	if (!asoc->peer.asconf_capable)
		return -EPERM;

	if (asoc->peer.addip_disabled_mask & SCTP_PARAM_SET_PRIMARY)
		return -EPERM;

	if (!sctp_state(asoc, ESTABLISHED))
		return -ENOTCONN;

	af = sctp_get_af_specific(prim.sspp_addr.ss_family);
	if (!af)
		return -EINVAL;

	if (!af->addr_valid((union sctp_addr *)&prim.sspp_addr, sp, NULL))
		return -EADDRNOTAVAIL;

	if (!sctp_assoc_lookup_laddr(asoc, (union sctp_addr *)&prim.sspp_addr))
		return -EADDRNOTAVAIL;

	/* Create an ASCONF chunk with SET_PRIMARY parameter	*/
	chunk = sctp_make_asconf_set_prim(asoc,
					  (union sctp_addr *)&prim.sspp_addr);
	if (!chunk)
		return -ENOMEM;

	err = sctp_send_asconf(asoc, chunk);

	pr_debug("%s: we set peer primary addr primitively\n", __func__);

	return err;
}

static int sctp_setsockopt_adaptation_layer(struct sock *sk, char __user *optval,
					    unsigned int optlen)
{
	struct sctp_setadaptation adaptation;

	if (optlen != sizeof(struct sctp_setadaptation))
		return -EINVAL;
	if (copy_from_user(&adaptation, optval, optlen))
		return -EFAULT;

	sctp_sk(sk)->adaptation_ind = adaptation.ssb_adaptation_ind;

	return 0;
}

/*
 * 7.1.29.  Set or Get the default context (SCTP_CONTEXT)
 *
 * The context field in the sctp_sndrcvinfo structure is normally only
 * used when a failed message is retrieved holding the value that was
 * sent down on the actual send call.  This option allows the setting of
 * a default context on an association basis that will be received on
 * reading messages from the peer.  This is especially helpful in the
 * one-2-many model for an application to keep some reference to an
 * internal state machine that is processing messages on the
 * association.  Note that the setting of this value only effects
 * received messages from the peer and does not effect the value that is
 * saved with outbound messages.
 */
static int sctp_setsockopt_context(struct sock *sk, char __user *optval,
				   unsigned int optlen)
{
	struct sctp_assoc_value params;
	struct sctp_sock *sp;
	struct sctp_association *asoc;

	if (optlen != sizeof(struct sctp_assoc_value))
		return -EINVAL;
	if (copy_from_user(&params, optval, optlen))
		return -EFAULT;

	sp = sctp_sk(sk);

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

	return 0;
}

/*
 * 7.1.24.  Get or set fragmented interleave (SCTP_FRAGMENT_INTERLEAVE)
 *
 * This options will at a minimum specify if the implementation is doing
 * fragmented interleave.  Fragmented interleave, for a one to many
 * socket, is when subsequent calls to receive a message may return
 * parts of messages from different associations.  Some implementations
 * may allow you to turn this value on or off.  If so, when turned off,
 * no fragment interleave will occur (which will cause a head of line
 * blocking amongst multiple associations sharing the same one to many
 * socket).  When this option is turned on, then each receive call may
 * come from a different association (thus the user must receive data
 * with the extended calls (e.g. sctp_recvmsg) to keep track of which
 * association each receive belongs to.
 *
 * This option takes a boolean value.  A non-zero value indicates that
 * fragmented interleave is on.  A value of zero indicates that
 * fragmented interleave is off.
 *
 * Note that it is important that an implementation that allows this
 * option to be turned on, have it off by default.  Otherwise an unaware
 * application using the one to many model may become confused and act
 * incorrectly.
 */
static int sctp_setsockopt_fragment_interleave(struct sock *sk,
					       char __user *optval,
					       unsigned int optlen)
{
	int val;

	if (optlen != sizeof(int))
		return -EINVAL;
	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	sctp_sk(sk)->frag_interleave = (val == 0) ? 0 : 1;

	return 0;
}

/*
 * 8.1.21.  Set or Get the SCTP Partial Delivery Point
 *       (SCTP_PARTIAL_DELIVERY_POINT)
 *
 * This option will set or get the SCTP partial delivery point.  This
 * point is the size of a message where the partial delivery API will be
 * invoked to help free up rwnd space for the peer.  Setting this to a
 * lower value will cause partial deliveries to happen more often.  The
 * calls argument is an integer that sets or gets the partial delivery
 * point.  Note also that the call will fail if the user attempts to set
 * this value larger than the socket receive buffer size.
 *
 * Note that any single message having a length smaller than or equal to
 * the SCTP partial delivery point will be delivered in one single read
 * call as long as the user provided buffer is large enough to hold the
 * message.
 */
static int sctp_setsockopt_partial_delivery_point(struct sock *sk,
						  char __user *optval,
						  unsigned int optlen)
{
	u32 val;

	if (optlen != sizeof(u32))
		return -EINVAL;
	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	/* Note: We double the receive buffer from what the user sets
	 * it to be, also initial rwnd is based on rcvbuf/2.
	 */
	if (val > (sk->sk_rcvbuf >> 1))
		return -EINVAL;

	sctp_sk(sk)->pd_point = val;

	return 0; /* is this the right error code? */
}

/*
 * 7.1.28.  Set or Get the maximum burst (SCTP_MAX_BURST)
 *
 * This option will allow a user to change the maximum burst of packets
 * that can be emitted by this association.  Note that the default value
 * is 4, and some implementations may restrict this setting so that it
 * can only be lowered.
 *
 * NOTE: This text doesn't seem right.  Do this on a socket basis with
 * future associations inheriting the socket value.
 */
static int sctp_setsockopt_maxburst(struct sock *sk,
				    char __user *optval,
				    unsigned int optlen)
{
	struct sctp_assoc_value params;
	struct sctp_sock *sp;
	struct sctp_association *asoc;
	int val;
	int assoc_id = 0;

	if (optlen == sizeof(int)) {
		pr_warn_ratelimited(DEPRECATED
				    "%s (pid %d) "
				    "Use of int in max_burst socket option deprecated.\n"
				    "Use struct sctp_assoc_value instead\n",
				    current->comm, task_pid_nr(current));
		if (copy_from_user(&val, optval, optlen))
			return -EFAULT;
	} else if (optlen == sizeof(struct sctp_assoc_value)) {
		if (copy_from_user(&params, optval, optlen))
			return -EFAULT;
		val = params.assoc_value;
		assoc_id = params.assoc_id;
	} else
		return -EINVAL;

	sp = sctp_sk(sk);

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

	return 0;
}

/*
 * 7.1.18.  Add a chunk that must be authenticated (SCTP_AUTH_CHUNK)
 *
 * This set option adds a chunk type that the user is requesting to be
 * received only in an authenticated way.  Changes to the list of chunks
 * will only effect future associations on the socket.
 */
static int sctp_setsockopt_auth_chunk(struct sock *sk,
				      char __user *optval,
				      unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_authchunk val;

	if (!net->sctp.auth_enable)
		return -EACCES;

	if (optlen != sizeof(struct sctp_authchunk))
		return -EINVAL;
	if (copy_from_user(&val, optval, optlen))
		return -EFAULT;

	switch (val.sauth_chunk) {
	case SCTP_CID_INIT:
	case SCTP_CID_INIT_ACK:
	case SCTP_CID_SHUTDOWN_COMPLETE:
	case SCTP_CID_AUTH:
		return -EINVAL;
	}

	/* add this chunk id to the endpoint */
	return sctp_auth_ep_add_chunkid(sctp_sk(sk)->ep, val.sauth_chunk);
}

/*
 * 7.1.19.  Get or set the list of supported HMAC Identifiers (SCTP_HMAC_IDENT)
 *
 * This option gets or sets the list of HMAC algorithms that the local
 * endpoint requires the peer to use.
 */
static int sctp_setsockopt_hmac_ident(struct sock *sk,
				      char __user *optval,
				      unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_hmacalgo *hmacs;
	u32 idents;
	int err;

	if (!net->sctp.auth_enable)
		return -EACCES;

	if (optlen < sizeof(struct sctp_hmacalgo))
		return -EINVAL;

	hmacs = memdup_user(optval, optlen);
	if (IS_ERR(hmacs))
		return PTR_ERR(hmacs);

	idents = hmacs->shmac_num_idents;
	if (idents == 0 || idents > SCTP_AUTH_NUM_HMACS ||
	    (idents * sizeof(u16)) > (optlen - sizeof(struct sctp_hmacalgo))) {
		err = -EINVAL;
		goto out;
	}

	err = sctp_auth_ep_set_hmacs(sctp_sk(sk)->ep, hmacs);
out:
	kfree(hmacs);
	return err;
}

/*
 * 7.1.20.  Set a shared key (SCTP_AUTH_KEY)
 *
 * This option will set a shared secret key which is used to build an
 * association shared key.
 */
static int sctp_setsockopt_auth_key(struct sock *sk,
				    char __user *optval,
				    unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_authkey *authkey;
	struct sctp_association *asoc;
	int ret;

	if (!net->sctp.auth_enable)
		return -EACCES;

	if (optlen <= sizeof(struct sctp_authkey))
		return -EINVAL;

	authkey = memdup_user(optval, optlen);
	if (IS_ERR(authkey))
		return PTR_ERR(authkey);

	if (authkey->sca_keylength > optlen - sizeof(struct sctp_authkey)) {
		ret = -EINVAL;
		goto out;
	}

	asoc = sctp_id2assoc(sk, authkey->sca_assoc_id);
	if (!asoc && authkey->sca_assoc_id && sctp_style(sk, UDP)) {
		ret = -EINVAL;
		goto out;
	}

	ret = sctp_auth_set_key(sctp_sk(sk)->ep, asoc, authkey);
out:
	kzfree(authkey);
	return ret;
}

/*
 * 7.1.21.  Get or set the active shared key (SCTP_AUTH_ACTIVE_KEY)
 *
 * This option will get or set the active shared key to be used to build
 * the association shared key.
 */
static int sctp_setsockopt_active_key(struct sock *sk,
				      char __user *optval,
				      unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_authkeyid val;
	struct sctp_association *asoc;

	if (!net->sctp.auth_enable)
		return -EACCES;

	if (optlen != sizeof(struct sctp_authkeyid))
		return -EINVAL;
	if (copy_from_user(&val, optval, optlen))
		return -EFAULT;

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

	return sctp_auth_set_active_key(sctp_sk(sk)->ep, asoc,
					val.scact_keynumber);
}

/*
 * 7.1.22.  Delete a shared key (SCTP_AUTH_DELETE_KEY)
 *
 * This set option will delete a shared secret key from use.
 */
static int sctp_setsockopt_del_key(struct sock *sk,
				   char __user *optval,
				   unsigned int optlen)
{
	struct net *net = sock_net(sk);
	struct sctp_authkeyid val;
	struct sctp_association *asoc;

	if (!net->sctp.auth_enable)
		return -EACCES;

	if (optlen != sizeof(struct sctp_authkeyid))
		return -EINVAL;
	if (copy_from_user(&val, optval, optlen))
		return -EFAULT;

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

	return sctp_auth_del_key_id(sctp_sk(sk)->ep, asoc,
				    val.scact_keynumber);

}

/*
 * 8.1.23 SCTP_AUTO_ASCONF
 *
 * This option will enable or disable the use of the automatic generation of
 * ASCONF chunks to add and delete addresses to an existing association.  Note
 * that this option has two caveats namely: a) it only affects sockets that
 * are bound to all addresses available to the SCTP stack, and b) the system
 * administrator may have an overriding control that turns the ASCONF feature
 * off no matter what setting the socket option may have.
 * This option expects an integer boolean flag, where a non-zero value turns on
 * the option, and a zero value turns off the option.
 * Note. In this implementation, socket operation overrides default parameter
 * being set by sysctl as well as FreeBSD implementation
 */
static int sctp_setsockopt_auto_asconf(struct sock *sk, char __user *optval,
					unsigned int optlen)
{
	int val;
	struct sctp_sock *sp = sctp_sk(sk);

	if (optlen < sizeof(int))
		return -EINVAL;
	if (get_user(val, (int __user *)optval))
		return -EFAULT;
	if (!sctp_is_ep_boundall(sk) && val)
		return -EINVAL;
	if ((val && sp->do_auto_asconf) || (!val && !sp->do_auto_asconf))
		return 0;

	if (val == 0 && sp->do_auto_asconf) {
		list_del(&sp->auto_asconf_list);
		sp->do_auto_asconf = 0;
	} else if (val && !sp->do_auto_asconf) {
		list_add_tail(&sp->auto_asconf_list,
		    &sock_net(sk)->sctp.auto_asconf_splist);
		sp->do_auto_asconf = 1;
	}
	return 0;
}


/*
 * SCTP_PEER_ADDR_THLDS
 *
 * This option allows us to alter the partially failed threshold for one or all
 * transports in an association.  See Section 6.1 of:
 * http://www.ietf.org/id/draft-nishida-tsvwg-sctp-failover-05.txt
 */
static int sctp_setsockopt_paddr_thresholds(struct sock *sk,
					    char __user *optval,
					    unsigned int optlen)
{
	struct sctp_paddrthlds val;
	struct sctp_transport *trans;
	struct sctp_association *asoc;

	if (optlen < sizeof(struct sctp_paddrthlds))
		return -EINVAL;
	if (copy_from_user(&val, (struct sctp_paddrthlds __user *)optval,
			   sizeof(struct sctp_paddrthlds)))
		return -EFAULT;


	if (sctp_is_any(sk, (const union sctp_addr *)&val.spt_address)) {
		asoc = sctp_id2assoc(sk, val.spt_assoc_id);
		if (!asoc)
			return -ENOENT;
		list_for_each_entry(trans, &asoc->peer.transport_addr_list,
				    transports) {
			if (val.spt_pathmaxrxt)
				trans->pathmaxrxt = val.spt_pathmaxrxt;
			trans->pf_retrans = val.spt_pathpfthld;
		}

		if (val.spt_pathmaxrxt)
			asoc->pathmaxrxt = val.spt_pathmaxrxt;
		asoc->pf_retrans = val.spt_pathpfthld;
	} else {
		trans = sctp_addr_id2transport(sk, &val.spt_address,
					       val.spt_assoc_id);
		if (!trans)
			return -ENOENT;

		if (val.spt_pathmaxrxt)
			trans->pathmaxrxt = val.spt_pathmaxrxt;
		trans->pf_retrans = val.spt_pathpfthld;
	}

	return 0;
}

/* API 6.2 setsockopt(), getsockopt()
 *
 * Applications use setsockopt() and getsockopt() to set or retrieve
 * socket options.  Socket options are used to change the default
 * behavior of sockets calls.  They are described in Section 7.
 *
 * The syntax is:
 *
 *   ret = getsockopt(int sd, int level, int optname, void __user *optval,
 *                    int __user *optlen);
 *   ret = setsockopt(int sd, int level, int optname, const void __user *optval,
 *                    int optlen);
 *
 *   sd      - the socket descript.
 *   level   - set to IPPROTO_SCTP for all SCTP options.
 *   optname - the option name.
 *   optval  - the buffer to store the value of the option.
 *   optlen  - the size of the buffer.
 */
static int sctp_setsockopt(struct sock *sk, int level, int optname,
			   char __user *optval, unsigned int optlen)
{
	int retval = 0;

	pr_debug("%s: sk:%p, optname:%d\n", __func__, 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 setsockopt() 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->setsockopt(sk, level, optname, optval, optlen);
		goto out_nounlock;
	}

	lock_sock(sk);

	switch (optname) {
	case SCTP_SOCKOPT_BINDX_ADD:
		/* 'optlen' is the size of the addresses buffer. */
		retval = sctp_setsockopt_bindx(sk, (struct sockaddr __user *)optval,
					       optlen, SCTP_BINDX_ADD_ADDR);
		break;

	case SCTP_SOCKOPT_BINDX_REM:
		/* 'optlen' is the size of the addresses buffer. */
		retval = sctp_setsockopt_bindx(sk, (struct sockaddr __user *)optval,
					       optlen, SCTP_BINDX_REM_ADDR);
		break;

	case SCTP_SOCKOPT_CONNECTX_OLD:
		/* 'optlen' is the size of the addresses buffer. */
		retval = sctp_setsockopt_connectx_old(sk,
					    (struct sockaddr __user *)optval,
					    optlen);
		break;

	case SCTP_SOCKOPT_CONNECTX:
		/* 'optlen' is the size of the addresses buffer. */
		retval = sctp_setsockopt_connectx(sk,
					    (struct sockaddr __user *)optval,
					    optlen);
		break;

	case SCTP_DISABLE_FRAGMENTS:
		retval = sctp_setsockopt_disable_fragments(sk, optval, optlen);
		break;

	case SCTP_EVENTS:
		retval = sctp_setsockopt_events(sk, optval, optlen);
		break;

	case SCTP_AUTOCLOSE:
		retval = sctp_setsockopt_autoclose(sk, optval, optlen);
		break;

	case SCTP_PEER_ADDR_PARAMS:
		retval = sctp_setsockopt_peer_addr_params(sk, optval, optlen);
		break;

	case SCTP_DELAYED_SACK:
		retval = sctp_setsockopt_delayed_ack(sk, optval, optlen);
		break;
	case SCTP_PARTIAL_DELIVERY_POINT:
		retval = sctp_setsockopt_partial_delivery_point(sk, optval, optlen);
		break;

	case SCTP_INITMSG:
		retval = sctp_setsockopt_initmsg(sk, optval, optlen);
		break;
	case SCTP_DEFAULT_SEND_PARAM:
		retval = sctp_setsockopt_default_send_param(sk, optval,
							    optlen);
		break;
	case SCTP_PRIMARY_ADDR:
		retval = sctp_setsockopt_primary_addr(sk, optval, optlen);
		break;
	case SCTP_SET_PEER_PRIMARY_ADDR:
		retval = sctp_setsockopt_peer_primary_addr(sk, optval, optlen);
		break;
	case SCTP_NODELAY:
		retval = sctp_setsockopt_nodelay(sk, optval, optlen);
		break;
	case SCTP_RTOINFO:
		retval = sctp_setsockopt_rtoinfo(sk, optval, optlen);
		break;
	case SCTP_ASSOCINFO:
		retval = sctp_setsockopt_associnfo(sk, optval, optlen);
		break;
	case SCTP_I_WANT_MAPPED_V4_ADDR:
		retval = sctp_setsockopt_mappedv4(sk, optval, optlen);
		break;
	case SCTP_MAXSEG:
		retval = sctp_setsockopt_maxseg(sk, optval, optlen);
		break;
	case SCTP_ADAPTATION_LAYER:
		retval = sctp_setsockopt_adaptation_layer(sk, optval, optlen);
		break;
	case SCTP_CONTEXT:
		retval = sctp_setsockopt_context(sk, optval, optlen);
		break;
	case SCTP_FRAGMENT_INTERLEAVE:
		retval = sctp_setsockopt_fragment_interleave(sk, optval, optlen);
		break;
	case SCTP_MAX_BURST:
		retval = sctp_setsockopt_maxburst(sk, optval, optlen);
		break;
	case SCTP_AUTH_CHUNK:
		retval = sctp_setsockopt_auth_chunk(sk, optval, optlen);
		break;
	case SCTP_HMAC_IDENT:
		retval = sctp_setsockopt_hmac_ident(sk, optval, optlen);
		break;
	case SCTP_AUTH_KEY:
		retval = sctp_setsockopt_auth_key(sk, optval, optlen);
		break;
	case SCTP_AUTH_ACTIVE_KEY:
		retval = sctp_setsockopt_active_key(sk, optval, optlen);
		break;
	case SCTP_AUTH_DELETE_KEY:
		retval = sctp_setsockopt_del_key(sk, optval, optlen);
		break;
	case SCTP_AUTO_ASCONF:
		retval = sctp_setsockopt_auto_asconf(sk, optval, optlen);
		break;
	case SCTP_PEER_ADDR_THLDS:
		retval = sctp_setsockopt_paddr_thresholds(sk, optval, optlen);
		break;
	default:
		retval = -ENOPROTOOPT;
		break;
	}

	release_sock(sk);

out_nounlock:
	return retval;
}

/* API 3.1.6 connect() - UDP Style Syntax
 *
 * An application may use the connect() call in the UDP model to initiate an
 * association without sending data.
 *
 * The syntax is:
 *
 * ret = connect(int sd, const struct sockaddr *nam, socklen_t len);
 *
 * sd: the socket descriptor to have a new association added to.
 *
 * nam: the address structure (either struct sockaddr_in or struct
 *    sockaddr_in6 defined in RFC2553 [7]).
 *
 * len: the size of the address.
 */
static int sctp_connect(struct sock *sk, struct sockaddr *addr,
			int addr_len)
{
	int err = 0;
	struct sctp_af *af;

	lock_sock(sk);

	pr_debug("%s: sk:%p, sockaddr:%p, addr_len:%d\n", __func__, sk,
		 addr, addr_len);

	/* Validate addr_len before calling common connect/connectx routine. */
	af = sctp_get_af_specific(addr->sa_family);
	if (!af || addr_len < af->sockaddr_len) {
		err = -EINVAL;
	} else {
		/* Pass correct addr len to common routine (so it knows there
		 * is only one address being passed.
		 */
		err = __sctp_connect(sk, addr, af->sockaddr_len, NULL);
	}

	release_sock(sk);
	return err;
}

/* FIXME: Write comments. */
static int sctp_disconnect(struct sock *sk, int flags)
{
	return -EOPNOTSUPP; /* STUB */
}

/* 4.1.4 accept() - TCP Style Syntax
 *
 * Applications use accept() call to remove an established SCTP
 * association from the accept queue of the endpoint.  A new socket
 * descriptor will be returned from accept() to represent the newly
 * formed association.
 */
static struct sock *sctp_accept(struct sock *sk, int flags, int *err)
{
	struct sctp_sock *sp;
	struct sctp_endpoint *ep;
	struct sock *newsk = NULL;
	struct sctp_association *asoc;
	long timeo;
	int error = 0;

	lock_sock(sk);

	sp = sctp_sk(sk);
	ep = sp->ep;

	if (!sctp_style(sk, TCP)) {
		error = -EOPNOTSUPP;
		goto out;
	}

	if (!sctp_sstate(sk, LISTENING)) {
		error = -EINVAL;
		goto out;
	}

	timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

	error = sctp_wait_for_accept(sk, timeo);
	if (error)
		goto out;

	/* We treat the list of associations on the endpoint as the accept
	 * queue and pick the first association on the list.
	 */
	asoc = list_entry(ep->asocs.next, struct sctp_association, asocs);

	newsk = sp->pf->create_accept_sk(sk, asoc);
	if (!newsk) {
		error = -ENOMEM;
		goto out;
	}

	/* Populate the fields of the newsk from the oldsk and migrate the
	 * asoc to the newsk.
	 */
	sctp_sock_migrate(sk, newsk, asoc, SCTP_SOCKET_TCP);

out:
	release_sock(sk);
	*err = error;
	return newsk;
}

/* The SCTP ioctl handler. */
static int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
	int rc = -ENOTCONN;

	lock_sock(sk);

	/*
	 * SEQPACKET-style sockets in LISTENING state are valid, for
	 * SCTP, so only discard TCP-style sockets in LISTENING state.
	 */
	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
		goto out;

	switch (cmd) {
	case SIOCINQ: {
		struct sk_buff *skb;
		unsigned int amount = 0;

		skb = skb_peek(&sk->sk_receive_queue);
		if (skb != NULL) {
			/*
			 * We will only return the amount of this packet since
			 * that is all that will be read.
			 */
			amount = skb->len;
		}
		rc = put_user(amount, (int __user *)arg);
		break;
	}
	default:
		rc = -ENOIOCTLCMD;
		break;
	}
out:
	release_sock(sk);
	return rc;
}

/* This is the function which gets called during socket creation to
 * initialized the SCTP-specific portion of the sock.
 * The sock structure should already be zero-filled memory.
 */
static int sctp_init_sock(struct sock *sk)
{
	struct net *net = sock_net(sk);
	struct sctp_sock *sp;

	pr_debug("%s: sk:%p\n", __func__, sk);

	sp = sctp_sk(sk);

	/* Initialize the SCTP per socket area.  */
	switch (sk->sk_type) {
	case SOCK_SEQPACKET:
		sp->type = SCTP_SOCKET_UDP;
		break;
	case SOCK_STREAM:
		sp->type = SCTP_SOCKET_TCP;
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	/* Initialize default send parameters. These parameters can be
	 * modified with the SCTP_DEFAULT_SEND_PARAM socket option.
	 */
	sp->default_stream = 0;
	sp->default_ppid = 0;
	sp->default_flags = 0;
	sp->default_context = 0;
	sp->default_timetolive = 0;

	sp->default_rcv_context = 0;
	sp->max_burst = net->sctp.max_burst;

	sp->sctp_hmac_alg = net->sctp.sctp_hmac_alg;

	/* Initialize default setup parameters. These parameters
	 * can be modified with the SCTP_INITMSG socket option or
	 * overridden by the SCTP_INIT CMSG.
	 */
	sp->initmsg.sinit_num_ostreams   = sctp_max_outstreams;
	sp->initmsg.sinit_max_instreams  = sctp_max_instreams;
	sp->initmsg.sinit_max_attempts   = net->sctp.max_retrans_init;
	sp->initmsg.sinit_max_init_timeo = net->sctp.rto_max;

	/* Initialize default RTO related parameters.  These parameters can
	 * be modified for with the SCTP_RTOINFO socket option.
	 */
	sp->rtoinfo.srto_initial = net->sctp.rto_initial;
	sp->rtoinfo.srto_max     = net->sctp.rto_max;
	sp->rtoinfo.srto_min     = net->sctp.rto_min;

	/* Initialize default association related parameters. These parameters
	 * can be modified with the SCTP_ASSOCINFO socket option.
	 */
	sp->assocparams.sasoc_asocmaxrxt = net->sctp.max_retrans_association;
	sp->assocparams.sasoc_number_peer_destinations = 0;
	sp->assocparams.sasoc_peer_rwnd = 0;
	sp->assocparams.sasoc_local_rwnd = 0;
	sp->assocparams.sasoc_cookie_life = net->sctp.valid_cookie_life;

	/* Initialize default event subscriptions. By default, all the
	 * options are off.
	 */
	memset(&sp->subscribe, 0, sizeof(struct sctp_event_subscribe));

	/* Default Peer Address Parameters.  These defaults can
	 * be modified via SCTP_PEER_ADDR_PARAMS
	 */
	sp->hbinterval  = net->sctp.hb_interval;
	sp->pathmaxrxt  = net->sctp.max_retrans_path;
	sp->pathmtu     = 0; /* allow default discovery */
	sp->sackdelay   = net->sctp.sack_timeout;
	sp->sackfreq	= 2;
	sp->param_flags = SPP_HB_ENABLE |
			  SPP_PMTUD_ENABLE |
			  SPP_SACKDELAY_ENABLE;

	/* If enabled no SCTP message fragmentation will be performed.
	 * Configure through SCTP_DISABLE_FRAGMENTS socket option.
	 */
	sp->disable_fragments = 0;

	/* Enable Nagle algorithm by default.  */
	sp->nodelay           = 0;

	/* Enable by default. */
	sp->v4mapped          = 1;

	/* Auto-close idle associations after the configured
	 * number of seconds.  A value of 0 disables this
	 * feature.  Configure through the SCTP_AUTOCLOSE socket option,
	 * for UDP-style sockets only.
	 */
	sp->autoclose         = 0;

	/* User specified fragmentation limit. */
	sp->user_frag         = 0;

	sp->adaptation_ind = 0;

	sp->pf = sctp_get_pf_specific(sk->sk_family);

	/* Control variables for partial data delivery. */
	atomic_set(&sp->pd_mode, 0);
	skb_queue_head_init(&sp->pd_lobby);
	sp->frag_interleave = 0;

	/* Create a per socket endpoint structure.  Even if we
	 * change the data structure relationships, this may still
	 * be useful for storing pre-connect address information.
	 */
	sp->ep = sctp_endpoint_new(sk, GFP_KERNEL);
	if (!sp->ep)
		return -ENOMEM;

	sp->hmac = NULL;

	sk->sk_destruct = sctp_destruct_sock;

	SCTP_DBG_OBJCNT_INC(sock);

	local_bh_disable();
	percpu_counter_inc(&sctp_sockets_allocated);
	sock_prot_inuse_add(net, sk->sk_prot, 1);
	if (net->sctp.default_auto_asconf) {
		list_add_tail(&sp->auto_asconf_list,
		    &net->sctp.auto_asconf_splist);
		sp->do_auto_asconf = 1;
	} else
		sp->do_auto_asconf = 0;
	local_bh_enable();

	return 0;
}