/kernel/linux-source-2.6.32/net/sctp/socket.c

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/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001-2003 Intel Corp.
 * Copyright (c) 2001-2002 Nokia, Inc.
 * Copyright (c) 2001 La Monte H.P. Yarroll
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions interface with the sockets layer to implement the
 * SCTP Extensions for the Sockets API.
 *
 * Note that the descriptions from the specification are USER level
 * functions--this file is the functions which populate the struct proto
 * for SCTP which is the BOTTOM of the sockets interface.
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <lksctp-developers@lists.sourceforge.net>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Narasimha Budihal     <narsi@refcode.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Xingang Guo           <xingang.guo@intel.com>
 *    Daisy Chang           <daisyc@us.ibm.com>
 *    Sridhar Samudrala     <samudrala@us.ibm.com>
 *    Inaky Perez-Gonzalez  <inaky.gonzalez@intel.com>
 *    Ardelle Fan	    <ardelle.fan@intel.com>
 *    Ryan Layer	    <rmlayer@us.ibm.com>
 *    Anup Pemmaiah         <pemmaiah@cc.usu.edu>
 *    Kevin Gao             <kevin.gao@intel.com>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/time.h>
#include <linux/ip.h>
#include <linux/capability.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/crypto.h>

#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/ipv6.h>
#include <net/inet_common.h>

#include <linux/socket.h> /* for sa_family_t */
#include <net/sock.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

/* WARNING:  Please do not remove the SCTP_STATIC attribute to
 * any of the functions below as they are used to export functions
 * used by a project regression testsuite.
 */

/* Forward declarations for internal helper functions. */
static int sctp_writeable(struct sock *sk);
static void sctp_wfree(struct sk_buff *skb);
static int sctp_wait_for_sndbuf(struct sctp_association *, long *timeo_p,
				size_t msg_len);
static int sctp_wait_for_packet(struct sock * sk, int *err, long *timeo_p);
static int sctp_wait_for_connect(struct sctp_association *, long *timeo_p);
static int sctp_wait_for_accept(struct sock *sk, long timeo);
static void sctp_wait_for_close(struct sock *sk, long timeo);
static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt,
					union sctp_addr *addr, int len);
static int sctp_bindx_add(struct sock *, struct sockaddr *, int);
static int sctp_bindx_rem(struct sock *, struct sockaddr *, int);
static int sctp_send_asconf_add_ip(struct sock *, struct sockaddr *, int);
static int sctp_send_asconf_del_ip(struct sock *, struct sockaddr *, int);
static int sctp_send_asconf(struct sctp_association *asoc,
			    struct sctp_chunk *chunk);
static int sctp_do_bind(struct sock *, union sctp_addr *, int);
static int sctp_autobind(struct sock *sk);
static void sctp_sock_migrate(struct sock *, struct sock *,
			      struct sctp_association *, sctp_socket_type_t);
static char *sctp_hmac_alg = SCTP_COOKIE_HMAC_ALG;

extern struct kmem_cache *sctp_bucket_cachep;
extern int sysctl_sctp_mem[3];
extern int sysctl_sctp_rmem[3];
extern int sysctl_sctp_wmem[3];

static int sctp_memory_pressure;
static atomic_t sctp_memory_allocated;
struct percpu_counter sctp_sockets_allocated;

static void sctp_enter_memory_pressure(struct sock *sk)
{
	sctp_memory_pressure = 1;
}


/* Get the sndbuf space available at the time on the association.  */
static inline int sctp_wspace(struct sctp_association *asoc)
{
	int amt;

	if (asoc->ep->sndbuf_policy)
		amt = asoc->sndbuf_used;
	else
		amt = sk_wmem_alloc_get(asoc->base.sk);

	if (amt >= asoc->base.sk->sk_sndbuf) {
		if (asoc->base.sk->sk_userlocks & SOCK_SNDBUF_LOCK)
			amt = 0;
		else {
			amt = sk_stream_wspace(asoc->base.sk);
			if (amt < 0)
				amt = 0;
		}
	} else {
		amt = asoc->base.sk->sk_sndbuf - amt;
	}
	return amt;
}

/* Increment the used sndbuf space count of the corresponding association by
 * the size of the outgoing data chunk.
 * Also, set the skb destructor for sndbuf accounting later.
 *
 * Since it is always 1-1 between chunk and skb, and also a new skb is always
 * allocated for chunk bundling in sctp_packet_transmit(), we can use the
 * destructor in the data chunk skb for the purpose of the sndbuf space
 * tracking.
 */
static inline void sctp_set_owner_w(struct sctp_chunk *chunk)
{
	struct sctp_association *asoc = chunk->asoc;
	struct sock *sk = asoc->base.sk;

	/* The sndbuf space is tracked per association.  */
	sctp_association_hold(asoc);

	skb_set_owner_w(chunk->skb, sk);

	chunk->skb->destructor = sctp_wfree;
	/* Save the chunk pointer in skb for sctp_wfree to use later.  */
	*((struct sctp_chunk **)(chunk->skb->cb)) = chunk;

	asoc->sndbuf_used += SCTP_DATA_SNDSIZE(chunk) +
				sizeof(struct sk_buff) +
				sizeof(struct sctp_chunk);

	atomic_add(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
	sk->sk_wmem_queued += chunk->skb->truesize;
	sk_mem_charge(sk, chunk->skb->truesize);
}

/* Verify that this is a valid address. */
static inline int sctp_verify_addr(struct sock *sk, union sctp_addr *addr,
				   int len)
{
	struct sctp_af *af;

	/* Verify basic sockaddr. */
	af = sctp_sockaddr_af(sctp_sk(sk), addr, len);
	if (!af)
		return -EINVAL;

	/* Is this a valid SCTP address?  */
	if (!af->addr_valid(addr, sctp_sk(sk), NULL))
		return -EINVAL;

	if (!sctp_sk(sk)->pf->send_verify(sctp_sk(sk), (addr)))
		return -EINVAL;

	return 0;
}

/* Look up the association by its id.  If this is not a UDP-style
 * socket, the ID field is always ignored.
 */
struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id)
{
	struct sctp_association *asoc = NULL;

	/* If this is not a UDP-style socket, assoc id should be ignored. */
	if (!sctp_style(sk, UDP)) {
		/* Return NULL if the socket state is not ESTABLISHED. It
		 * could be a TCP-style listening socket or a socket which
		 * hasn't yet called connect() to establish an association.
		 */
		if (!sctp_sstate(sk, ESTABLISHED))
			return NULL;

		/* Get the first and the only association from the list. */
		if (!list_empty(&sctp_sk(sk)->ep->asocs))
			asoc = list_entry(sctp_sk(sk)->ep->asocs.next,
					  struct sctp_association, asocs);
		return asoc;
	}

	/* Otherwise this is a UDP-style socket. */
	if (!id || (id == (sctp_assoc_t)-1))
		return NULL;

	spin_lock_bh(&sctp_assocs_id_lock);
	asoc = (struct sctp_association *)idr_find(&sctp_assocs_id, (int)id);
	spin_unlock_bh(&sctp_assocs_id_lock);

	if (!asoc || (asoc->base.sk != sk) || asoc->base.dead)
		return NULL;

	return asoc;
}

/* Look up the transport from an address and an assoc id. If both address and
 * id are specified, the associations matching the address and the id should be
 * the same.
 */
static struct sctp_transport *sctp_addr_id2transport(struct sock *sk,
					      struct sockaddr_storage *addr,
					      sctp_assoc_t id)
{
	struct sctp_association *addr_asoc = NULL, *id_asoc = NULL;
	struct sctp_transport *transport;
	union sctp_addr *laddr = (union sctp_addr *)addr;

	addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,
					       laddr,
					       &transport);

	if (!addr_asoc)
		return NULL;

	id_asoc = sctp_id2assoc(sk, id);
	if (id_asoc && (id_asoc != addr_asoc))
		return NULL;

	sctp_get_pf_specific(sk->sk_family)->addr_v4map(sctp_sk(sk),
						(union sctp_addr *)addr);

	return transport;
}

/* API 3.1.2 bind() - UDP Style Syntax
 * The syntax of bind() is,
 *
 *   ret = bind(int sd, struct sockaddr *addr, int addrlen);
 *
 *   sd      - the socket descriptor returned by socket().
 *   addr    - the address structure (struct sockaddr_in or struct
 *             sockaddr_in6 [RFC 2553]),
 *   addr_len - the size of the address structure.
 */
SCTP_STATIC int sctp_bind(struct sock *sk, struct sockaddr *addr, int addr_len)
{
	int retval = 0;

	sctp_lock_sock(sk);

	SCTP_DEBUG_PRINTK("sctp_bind(sk: %p, addr: %p, addr_len: %d)\n",
			  sk, addr, addr_len);

	/* Disallow binding twice. */
	if (!sctp_sk(sk)->ep->base.bind_addr.port)
		retval = sctp_do_bind(sk, (union sctp_addr *)addr,
				      addr_len);
	else
		retval = -EINVAL;

	sctp_release_sock(sk);

	return retval;
}

static long sctp_get_port_local(struct sock *, union sctp_addr *);

/* Verify this is a valid sockaddr. */
static struct sctp_af *sctp_sockaddr_af(struct sctp_sock *opt,
					union sctp_addr *addr, int len)
{
	struct sctp_af *af;

	/* Check minimum size.  */
	if (len < sizeof (struct sockaddr))
		return NULL;

	/* V4 mapped address are really of AF_INET family */
	if (addr->sa.sa_family == AF_INET6 &&
	    ipv6_addr_v4mapped(&addr->v6.sin6_addr)) {
		if (!opt->pf->af_supported(AF_INET, opt))
			return NULL;
	} else {
		/* Does this PF support this AF? */
		if (!opt->pf->af_supported(addr->sa.sa_family, opt))
			return NULL;
	}

	/* If we get this far, af is valid. */
	af = sctp_get_af_specific(addr->sa.sa_family);

	if (len < af->sockaddr_len)
		return NULL;

	return af;
}

/* Bind a local address either to an endpoint or to an association.  */
SCTP_STATIC int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
{
	struct sctp_sock *sp = sctp_sk(sk);
	struct sctp_endpoint *ep = sp->ep;
	struct sctp_bind_addr *bp = &ep->base.bind_addr;
	struct sctp_af *af;
	unsigned short snum;
	int ret = 0;

	/* Common sockaddr verification. */
	af = sctp_sockaddr_af(sp, addr, len);
	if (!af) {
		SCTP_DEBUG_PRINTK("sctp_do_bind(sk: %p, newaddr: %p, len: %d) EINVAL\n",
				  sk, addr, len);
		return -EINVAL;
	}

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

	SCTP_DEBUG_PRINTK_IPADDR("sctp_do_bind(sk: %p, new addr: ",
				 ", port: %d, new port: %d, len: %d)\n",
				 sk,
				 addr,
				 bp->port, snum,
				 len);

	/* PF specific bind() address verification. */
	if (!sp->pf->bind_verify(sp, addr))
		return -EADDRNOTAVAIL;

	/* We must either be unbound, or bind to the same port.
	 * It's OK to allow 0 ports if we are already bound.
	 * We'll just inhert an already bound port in this case
	 */
	if (bp->port) {
		if (!snum)
			snum = bp->port;
		else if (snum != bp->port) {
			SCTP_DEBUG_PRINTK("sctp_do_bind:"
				  " New port %d does not match existing port "
				  "%d.\n", snum, bp->port);
			return -EINVAL;
		}
	}

	if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE))
		return -EACCES;

	/* See if the address matches any of the addresses we may have
	 * already bound before checking against other endpoints.
	 */
	if (sctp_bind_addr_match(bp, addr, sp))
		return -EINVAL;

	/* Make sure we are allowed to bind here.
	 * The function sctp_get_port_local() does duplicate address
	 * detection.
	 */
	addr->v4.sin_port = htons(snum);
	if ((ret = sctp_get_port_local(sk, addr))) {
		return -EADDRINUSE;
	}

	/* Refresh ephemeral port.  */
	if (!bp->port)
		bp->port = inet_sk(sk)->num;

	/* Add the address to the bind address list.
	 * Use GFP_ATOMIC since BHs will be disabled.
	 */
	ret = sctp_add_bind_addr(bp, addr, SCTP_ADDR_SRC, GFP_ATOMIC);

	/* Copy back into socket for getsockname() use. */
	if (!ret) {
		inet_sk(sk)->sport = htons(inet_sk(sk)->num);
		af->to_sk_saddr(addr, sk);
	}

	return ret;
}

 /* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
 *
 * R1) One and only one ASCONF Chunk MAY be in transit and unacknowledged
 * at any one time.  If a sender, after sending an ASCONF chunk, decides
 * it needs to transfer another ASCONF Chunk, it MUST wait until the
 * ASCONF-ACK Chunk returns from the previous ASCONF Chunk before sending a
 * subsequent ASCONF. Note this restriction binds each side, so at any
 * time two ASCONF may be in-transit on any given association (one sent
 * from each endpoint).
 */
static int sctp_send_asconf(struct sctp_association *asoc,
			    struct sctp_chunk *chunk)
{
	int		retval = 0;

	/* If there is an outstanding ASCONF chunk, queue it for later
	 * transmission.
	 */
	if (asoc->addip_last_asconf) {
		list_add_tail(&chunk->list, &asoc->addip_chunk_list);
		goto out;
	}

	/* Hold the chunk until an ASCONF_ACK is received. */
	sctp_chunk_hold(chunk);
	retval = sctp_primitive_ASCONF(asoc, chunk);
	if (retval)
		sctp_chunk_free(chunk);
	else
		asoc->addip_last_asconf = chunk;

out:
	return retval;
}

/* Add a list of addresses as bind addresses to local endpoint or
 * association.
 *
 * Basically run through each address specified in the addrs/addrcnt
 * array/length pair, determine if it is IPv6 or IPv4 and call
 * sctp_do_bind() on it.
 *
 * If any of them fails, then the operation will be reversed and the
 * ones that were added will be removed.
 *
 * Only sctp_setsockopt_bindx() is supposed to call this function.
 */
static int sctp_bindx_add(struct sock *sk, struct sockaddr *addrs, int addrcnt)
{
	int cnt;
	int retval = 0;
	void *addr_buf;
	struct sockaddr *sa_addr;
	struct sctp_af *af;

	SCTP_DEBUG_PRINTK("sctp_bindx_add (sk: %p, addrs: %p, addrcnt: %d)\n",
			  sk, addrs, addrcnt);

	addr_buf = addrs;
	for (cnt = 0; cnt < addrcnt; cnt++) {
		/* The list may contain either IPv4 or IPv6 address;
		 * determine the address length for walking thru the list.
		 */
		sa_addr = (struct sockaddr *)addr_buf;
		af = sctp_get_af_specific(sa_addr->sa_family);
		if (!af) {
			retval = -EINVAL;
			goto err_bindx_add;
		}

		retval = sctp_do_bind(sk, (union sctp_addr *)sa_addr,
				      af->sockaddr_len);

		addr_buf += af->sockaddr_len;

err_bindx_add:
		if (retval < 0) {
			/* Failed. Cleanup the ones that have been added */
			if (cnt > 0)
				sctp_bindx_rem(sk, addrs, cnt);
			return retval;
		}
	}

	return retval;
}

/* Send an ASCONF chunk with Add IP address parameters to all the peers of the
 * associations that are part of the endpoint indicating that a list of local
 * addresses are added to the endpoint.
 *
 * If any of the addresses is already in the bind address list of the
 * association, we do not send the chunk for that association.  But it will not
 * affect other associations.
 *
 * Only sctp_setsockopt_bindx() is supposed to call this function.
 */
static int sctp_send_asconf_add_ip(struct sock		*sk,
				   struct sockaddr	*addrs,
				   int 			addrcnt)
{
	struct sctp_sock		*sp;
	struct sctp_endpoint		*ep;
	struct sctp_association		*asoc;
	struct sctp_bind_addr		*bp;
	struct sctp_chunk		*chunk;
	struct sctp_sockaddr_entry	*laddr;
	union sctp_addr			*addr;
	union sctp_addr			saveaddr;
	void				*addr_buf;
	struct sctp_af			*af;
	struct list_head		*p;
	int 				i;
	int 				retval = 0;

	if (!sctp_addip_enable)
		return retval;

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

	SCTP_DEBUG_PRINTK("%s: (sk: %p, addrs: %p, addrcnt: %d)\n",
			  __func__, sk, addrs, addrcnt);

	list_for_each_entry(asoc, &ep->asocs, asocs) {

		if (!asoc->peer.asconf_capable)
			continue;

		if (asoc->peer.addip_disabled_mask & SCTP_PARAM_ADD_IP)
			continue;

		if (!sctp_state(asoc, ESTABLISHED))
			continue;

		/* Check if any address in the packed array of addresses is
		 * in the bind address list of the association. If so,
		 * do not send the asconf chunk to its peer, but continue with
		 * other associations.
		 */
		addr_buf = addrs;
		for (i = 0; i < addrcnt; i++) {
			addr = (union sctp_addr *)addr_buf;
			af = sctp_get_af_specific(addr->v4.sin_family);
			if (!af) {
				retval = -EINVAL;
				goto out;
			}

			if (sctp_assoc_lookup_laddr(asoc, addr))
				break;

			addr_buf += af->sockaddr_len;
		}
		if (i < addrcnt)
			continue;

		/* Use the first valid address in bind addr list of
		 * association as Address Parameter of ASCONF CHUNK.
		 */
		bp = &asoc->base.bind_addr;
		p = bp->address_list.next;
		laddr = list_entry(p, struct sctp_sockaddr_entry, list);
		chunk = sctp_make_asconf_update_ip(asoc, &laddr->a, addrs,
						   addrcnt, SCTP_PARAM_ADD_IP);
		if (!chunk) {
			retval = -ENOMEM;
			goto out;
		}

		retval = sctp_send_asconf(asoc, chunk);
		if (retval)
			goto out;

		/* Add the new addresses to the bind address list with
		 * use_as_src set to 0.
		 */
		addr_buf = addrs;
		for (i = 0; i < addrcnt; i++) {
			addr = (union sctp_addr *)addr_buf;
			af = sctp_get_af_specific(addr->v4.sin_family);
			memcpy(&saveaddr, addr, af->sockaddr_len);
			retval = sctp_add_bind_addr(bp, &saveaddr,
						    SCTP_ADDR_NEW, GFP_ATOMIC);
			addr_buf += af->sockaddr_len;
		}
	}

out:
	return retval;
}

/* Remove a list of addresses from bind addresses list.  Do not remove the
 * last address.
 *
 * Basically run through each address specified in the addrs/addrcnt
 * array/length pair, determine if it is IPv6 or IPv4 and call
 * sctp_del_bind() on it.
 *
 * If any of them fails, then the operation will be reversed and the
 * ones that were removed will be added back.
 *
 * At least one address has to be left; if only one address is
 * available, the operation will return -EBUSY.
 *
 * Only sctp_setsockopt_bindx() is supposed to call this function.
 */
static int sctp_bindx_rem(struct sock *sk, struct sockaddr *addrs, int addrcnt)
{
	struct sctp_sock *sp = sctp_sk(sk);
	struct sctp_endpoint *ep = sp->ep;
	int cnt;
	struct sctp_bind_addr *bp = &ep->base.bind_addr;
	int retval = 0;
	void *addr_buf;
	union sctp_addr *sa_addr;
	struct sctp_af *af;

	SCTP_DEBUG_PRINTK("sctp_bindx_rem (sk: %p, addrs: %p, addrcnt: %d)\n",
			  sk, addrs, addrcnt);

	addr_buf = addrs;
	for (cnt = 0; cnt < addrcnt; cnt++) {
		/* If the bind address list is empty or if there is only one
		 * bind address, there is nothing more to be removed (we need
		 * at least one address here).
		 */
		if (list_empty(&bp->address_list) ||
		    (sctp_list_single_entry(&bp->address_list))) {
			retval = -EBUSY;
			goto err_bindx_rem;
		}

		sa_addr = (union sctp_addr *)addr_buf;
		af = sctp_get_af_specific(sa_addr->sa.sa_family);
		if (!af) {
			retval = -EINVAL;
			goto err_bindx_rem;
		}

		if (!af->addr_valid(sa_addr, sp, NULL)) {
			retval = -EADDRNOTAVAIL;
			goto err_bindx_rem;
		}

		if (sa_addr->v4.sin_port != htons(bp->port)) {
			retval = -EINVAL;
			goto err_bindx_rem;
		}

		/* FIXME - There is probably a need to check if sk->sk_saddr and
		 * sk->sk_rcv_addr are currently set to one of the addresses to
		 * be removed. This is something which needs to be looked into
		 * when we are fixing the outstanding issues with multi-homing
		 * socket routing and failover schemes. Refer to comments in
		 * sctp_do_bind(). -daisy
		 */
		retval = sctp_del_bind_addr(bp, sa_addr);

		addr_buf += af->sockaddr_len;
err_bindx_rem:
		if (retval < 0) {
			/* Failed. Add the ones that has been removed back */
			if (cnt > 0)
				sctp_bindx_add(sk, addrs, cnt);
			return retval;
		}
	}

	return retval;
}

/* Send an ASCONF chunk with Delete IP address parameters to all the peers of
 * the associations that are part of the endpoint indicating that a list of
 * local addresses are removed from the endpoint.
 *
 * If any of the addresses is already in the bind address list of the
 * association, we do not send the chunk for that association.  But it will not
 * affect other associations.
 *
 * Only sctp_setsockopt_bindx() is supposed to call this function.
 */
static int sctp_send_asconf_del_ip(struct sock		*sk,
				   struct sockaddr	*addrs,
				   int			addrcnt)
{
	struct sctp_sock	*sp;
	struct sctp_endpoint	*ep;
	struct sctp_association	*asoc;
	struct sctp_transport	*transport;
	struct sctp_bind_addr	*bp;
	struct sctp_chunk	*chunk;
	union sctp_addr		*laddr;
	void			*addr_buf;
	struct sctp_af		*af;
	struct sctp_sockaddr_entry *saddr;
	int 			i;
	int 			retval = 0;

	if (!sctp_addip_enable)
		return retval;

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

	SCTP_DEBUG_PRINTK("%s: (sk: %p, addrs: %p, addrcnt: %d)\n",
			  __func__, sk, addrs, addrcnt);

	list_for_each_entry(asoc, &ep->asocs, asocs) {

		if (!asoc->peer.asconf_capable)
			continue;

		if (asoc->peer.addip_disabled_mask & SCTP_PARAM_DEL_IP)
			continue;

		if (!sctp_state(asoc, ESTABLISHED))
			continue;

		/* Check if any address in the packed array of addresses is
		 * not present in the bind address list of the association.
		 * If so, do not send the asconf chunk to its peer, but
		 * continue with other associations.
		 */
		addr_buf = addrs;
		for (i = 0; i < addrcnt; i++) {
			laddr = (union sctp_addr *)addr_buf;
			af = sctp_get_af_specific(laddr->v4.sin_family);
			if (!af) {
				retval = -EINVAL;
				goto out;
			}

			if (!sctp_assoc_lookup_laddr(asoc, laddr))
				break;

			addr_buf += af->sockaddr_len;
		}
		if (i < addrcnt)
			continue;

		/* Find one address in the association's bind address list
		 * that is not in the packed array of addresses. This is to
		 * make sure that we do not delete all the addresses in the
		 * association.
		 */
		bp = &asoc->base.bind_addr;
		laddr = sctp_find_unmatch_addr(bp, (union sctp_addr *)addrs,
					       addrcnt, sp);
		if (!laddr)
			continue;

		/* We do not need RCU protection throughout this loop
		 * because this is done under a socket lock from the
		 * setsockopt call.
		 */
		chunk = sctp_make_asconf_update_ip(asoc, laddr, addrs, addrcnt,
						   SCTP_PARAM_DEL_IP);
		if (!chunk) {
			retval = -ENOMEM;
			goto out;
		}

		/* Reset use_as_src flag for the addresses in the bind address
		 * list that are to be deleted.
		 */
		addr_buf = addrs;
		for (i = 0; i < addrcnt; i++) {
			laddr = (union sctp_addr *)addr_buf;
			af = sctp_get_af_specific(laddr->v4.sin_family);
			list_for_each_entry(saddr, &bp->address_list, list) {
				if (sctp_cmp_addr_exact(&saddr->a, laddr))
					saddr->state = SCTP_ADDR_DEL;
			}
			addr_buf += af->sockaddr_len;
		}

		/* Update the route and saddr entries for all the transports
		 * as some of the addresses in the bind address list are
		 * about to be deleted and cannot be used as source addresses.
		 */
		list_for_each_entry(transport, &asoc->peer.transport_addr_list,
					transports) {
			dst_release(transport->dst);
			sctp_transport_route(transport, NULL,
					     sctp_sk(asoc->base.sk));
		}

		retval = sctp_send_asconf(asoc, chunk);
	}
out:
	return retval;
}

/* Helper for tunneling sctp_bindx() requests through sctp_setsockopt()
 *
 * API 8.1
 * int sctp_bindx(int sd, struct sockaddr *addrs, int addrcnt,
 *                int flags);
 *
 * If sd is an IPv4 socket, the addresses passed must be IPv4 addresses.
 * If the sd is an IPv6 socket, the addresses passed can either be IPv4
 * or IPv6 addresses.
 *
 * A single address may be specified as INADDR_ANY or IN6ADDR_ANY, see
 * Section 3.1.2 for this usage.
 *
 * addrs is a pointer to an array of one or more socket addresses. Each
 * address is contained in its appropriate structure (i.e. struct
 * sockaddr_in or struct sockaddr_in6) the family of the address type
 * must be used to distinguish the address length (note that this
 * representation is termed a "packed array" of addresses). The caller
 * specifies the number of addresses in the array with addrcnt.
 *
 * On success, sctp_bindx() returns 0. On failure, sctp_bindx() returns
 * -1, and sets errno to the appropriate error code.
 *
 * For SCTP, the port given in each socket address must be the same, or
 * sctp_bindx() will fail, setting errno to EINVAL.
 *
 * The flags parameter is formed from the bitwise OR of zero or more of
 * the following currently defined flags:
 *
 * SCTP_BINDX_ADD_ADDR
 *
 * SCTP_BINDX_REM_ADDR
 *
 * SCTP_BINDX_ADD_ADDR directs SCTP to add the given addresses to the
 * association, and SCTP_BINDX_REM_ADDR directs SCTP to remove the given
 * addresses from the association. The two flags are mutually exclusive;
 * if both are given, sctp_bindx() will fail with EINVAL. A caller may
 * not remove all addresses from an association; sctp_bindx() will
 * reject such an attempt with EINVAL.
 *
 * An application can use sctp_bindx(SCTP_BINDX_ADD_ADDR) to associate
 * additional addresses with an endpoint after calling bind().  Or use
 * sctp_bindx(SCTP_BINDX_REM_ADDR) to remove some addresses a listening
 * socket is associated with so that no new association accepted will be
 * associated with those addresses. If the endpoint supports dynamic
 * address a SCTP_BINDX_REM_ADDR or SCTP_BINDX_ADD_ADDR may cause a
 * endpoint to send the appropriate message to the peer to change the
 * peers address lists.
 *
 * Adding and removing addresses from a connected association is
 * optional functionality. Implementations that do not support this
 * functionality should return EOPNOTSUPP.
 *
 * Basically do nothing but copying the addresses from user to kernel
 * land and invoking either sctp_bindx_add() or sctp_bindx_rem() on the sk.
 * This is used for tunneling the sctp_bindx() request through sctp_setsockopt()
 * from userspace.
 *
 * We don't use copy_from_user() for optimization: we first do the
 * sanity checks (buffer size -fast- and access check-healthy
 * pointer); if all of those succeed, then we can alloc the memory
 * (expensive operation) needed to copy the data to kernel. Then we do
 * the copying without checking the user space area
 * (__copy_from_user()).
 *
 * On exit there is no need to do sockfd_put(), sys_setsockopt() does
 * it.
 *
 * sk        The sk of the socket
 * addrs     The pointer to the addresses in user land
 * addrssize Size of the addrs buffer
 * op        Operation to perform (add or remove, see the flags of
 *           sctp_bindx)
 *
 * Returns 0 if ok, <0 errno code on error.
 */
SCTP_STATIC int sctp_setsockopt_bindx(struct sock* sk,
				      struct sockaddr __user *addrs,
				      int addrs_size, int op)
{
	struct sockaddr *kaddrs;
	int err;
	int addrcnt = 0;
	int walk_size = 0;
	struct sockaddr *sa_addr;
	void *addr_buf;
	struct sctp_af *af;

	SCTP_DEBUG_PRINTK("sctp_setsocktopt_bindx: sk %p addrs %p"
			  " addrs_size %d opt %d\n", sk, addrs, addrs_size, op);

	if (unlikely(addrs_size <= 0))
		return -EINVAL;

	/* Check the user passed a healthy pointer.  */
	if (unlikely(!access_ok(VERIFY_READ, addrs, addrs_size)))
		return -EFAULT;

	/* Alloc space for the address array in kernel memory.  */
	kaddrs = kmalloc(addrs_size, GFP_KERNEL);
	if (unlikely(!kaddrs))
		return -ENOMEM;

	if (__copy_from_user(kaddrs, addrs, addrs_size)) {
		kfree(kaddrs);
		return -EFAULT;
	}

	/* Walk through the addrs buffer and count the number of addresses. */
	addr_buf = kaddrs;
	while (walk_size < addrs_size) {
		sa_addr = (struct sockaddr *)addr_buf;
		af = sctp_get_af_specific(sa_addr->sa_family);

		/* If the address family is not supported or if this address
		 * causes the address buffer to overflow return EINVAL.
		 */
		if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
			kfree(kaddrs);
			return -EINVAL;
		}
		addrcnt++;
		addr_buf += af->sockaddr_len;
		walk_size += af->sockaddr_len;
	}

	/* Do the work. */
	switch (op) {
	case SCTP_BINDX_ADD_ADDR:
		err = sctp_bindx_add(sk, kaddrs, addrcnt);
		if (err)
			goto out;
		err = sctp_send_asconf_add_ip(sk, kaddrs, addrcnt);
		break;

	case SCTP_BINDX_REM_ADDR:
		err = sctp_bindx_rem(sk, kaddrs, addrcnt);
		if (err)
			goto out;
		err = sctp_send_asconf_del_ip(sk, kaddrs, addrcnt);
		break;

	default:
		err = -EINVAL;
		break;
	}

out:
	kfree(kaddrs);

	return err;
}

/* __sctp_connect(struct sock* sk, struct sockaddr *kaddrs, int addrs_size)
 *
 * Common routine for handling connect() and sctp_connectx().
 * Connect will come in with just a single address.
 */
static int __sctp_connect(struct sock* sk,
			  struct sockaddr *kaddrs,
			  int addrs_size,
			  sctp_assoc_t *assoc_id)
{
	struct sctp_sock *sp;
	struct sctp_endpoint *ep;
	struct sctp_association *asoc = NULL;
	struct sctp_association *asoc2;
	struct sctp_transport *transport;
	union sctp_addr to;
	struct sctp_af *af;
	sctp_scope_t scope;
	long timeo;
	int err = 0;
	int addrcnt = 0;
	int walk_size = 0;
	union sctp_addr *sa_addr = NULL;
	void *addr_buf;
	unsigned short port;
	unsigned int f_flags = 0;

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

	/* connect() cannot be done on a socket that is already in ESTABLISHED
	 * state - UDP-style peeled off socket or a TCP-style socket that
	 * is already connected.
	 * It cannot be done even on a TCP-style listening socket.
	 */
	if (sctp_sstate(sk, ESTABLISHED) ||
	    (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))) {
		err = -EISCONN;
		goto out_free;
	}

	/* Walk through the addrs buffer and count the number of addresses. */
	addr_buf = kaddrs;
	while (walk_size < addrs_size) {
		sa_addr = (union sctp_addr *)addr_buf;
		af = sctp_get_af_specific(sa_addr->sa.sa_family);
		port = ntohs(sa_addr->v4.sin_port);

		/* If the address family is not supported or if this address
		 * causes the address buffer to overflow return EINVAL.
		 */
		if (!af || (walk_size + af->sockaddr_len) > addrs_size) {
			err = -EINVAL;
			goto out_free;
		}

		/* Save current address so we can work with it */
		memcpy(&to, sa_addr, af->sockaddr_len);

		err = sctp_verify_addr(sk, &to, af->sockaddr_len);
		if (err)
			goto out_free;

		/* Make sure the destination port is correctly set
		 * in all addresses.
		 */
		if (asoc && asoc->peer.port && asoc->peer.port != port)
			goto out_free;


		/* Check if there already is a matching association on the
		 * endpoint (other than the one created here).
		 */
		asoc2 = sctp_endpoint_lookup_assoc(ep, &to, &transport);
		if (asoc2 && asoc2 != asoc) {
			if (asoc2->state >= SCTP_STATE_ESTABLISHED)
				err = -EISCONN;
			else
				err = -EALREADY;
			goto out_free;
		}

		/* If we could not find a matching association on the endpoint,
		 * make sure that there is no peeled-off association matching
		 * the peer address even on another socket.
		 */
		if (sctp_endpoint_is_peeled_off(ep, &to)) {
			err = -EADDRNOTAVAIL;
			goto out_free;
		}

		if (!asoc) {
			/* If a bind() or sctp_bindx() is not called prior to
			 * an sctp_connectx() call, the system picks an
			 * ephemeral port and will choose an address set
			 * equivalent to binding with a wildcard address.
			 */
			if (!ep->base.bind_addr.port) {
				if (sctp_autobind(sk)) {
					err = -EAGAIN;
					goto out_free;
				}
			} else {
				/*
				 * If an unprivileged user inherits a 1-many
				 * style socket with open associations on a
				 * privileged port, it MAY be permitted to
				 * accept new associations, but it SHOULD NOT
				 * be permitted to open new associations.
				 */
				if (ep->base.bind_addr.port < PROT_SOCK &&
				    !capable(CAP_NET_BIND_SERVICE)) {
					err = -EACCES;
					goto out_free;
				}
			}

			scope = sctp_scope(&to);
			asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
			if (!asoc) {
				err = -ENOMEM;
				goto out_free;
			}

			err = sctp_assoc_set_bind_addr_from_ep(asoc, scope,
							      GFP_KERNEL);
			if (err < 0) {
				goto out_free;
			}

		}

		/* Prime the peer's transport structures.  */
		transport = sctp_assoc_add_peer(asoc, &to, GFP_KERNEL,
						SCTP_UNKNOWN);
		if (!transport) {
			err = -ENOMEM;
			goto out_free;
		}

		addrcnt++;
		addr_buf += af->sockaddr_len;
		walk_size += af->sockaddr_len;
	}

	/* In case the user of sctp_connectx() wants an association
	 * id back, assign one now.
	 */
	if (assoc_id) {
		err = sctp_assoc_set_id(asoc, GFP_KERNEL);
		if (err < 0)
			goto out_free;
	}

	err = sctp_primitive_ASSOCIATE(asoc, NULL);
	if (err < 0) {
		goto out_free;
	}

	/* Initialize sk's dport and daddr for getpeername() */
	inet_sk(sk)->dport = htons(asoc->peer.port);
	af = sctp_get_af_specific(sa_addr->sa.sa_family);
	af->to_sk_daddr(sa_addr, sk);
	sk->sk_err = 0;

	/* in-kernel sockets don't generally have a file allocated to them
	 * if all they do is call sock_create_kern().
	 */
	if (sk->sk_socket->file)
		f_flags = sk->sk_socket->file->f_flags;

	timeo = sock_sndtimeo(sk, f_flags & O_NONBLOCK);

	err = sctp_wait_for_connect(asoc, &timeo);
	if ((err == 0 || err == -EINPROGRESS) && assoc_id)
		*assoc_id = asoc->assoc_id;

	/* Don't free association on exit. */
	asoc = NULL;

out_free:

	SCTP_DEBUG_PRINTK("About to exit __sctp_connect() free asoc: %p"
			  " kaddrs: %p err: %d\n",
			  asoc, kaddrs, err);
	if (asoc)
		sctp_association_free(asoc);
	return err;
}

/* Helper for tunneling sctp_connectx() requests through sctp_setsockopt()
 *
 * API 8.9
 * int sctp_connectx(int sd, struct sockaddr *addrs, int addrcnt,
 * 			sctp_assoc_t *asoc);
 *
 * If sd is an IPv4 socket, the addresses passed must be IPv4 addresses.
 * If the sd is an IPv6 socket, the addresses passed can either be IPv4
 * or IPv6 addresses.
 *
 * A single address may be specified as INADDR_ANY or IN6ADDR_ANY, see
 * Section 3.1.2 for this usage.
 *
 * addrs is a pointer to an array of one or more socket addresses. Each
 * address is contained in its appropriate structure (i.e. struct
 * sockaddr_in or struct sockaddr_in6) the family of the address type
 * must be used to distengish the address length (note that this
 * representation is termed a "packed array" of addresses). The caller
 * specifies the number of addresses in the array with addrcnt.
 *
 * On success, sctp_connectx() returns 0. It also sets the assoc_id to
 * the association id of the new association.  On failure, sctp_connectx()
 * returns -1, and sets errno to the appropriate error code.  The assoc_id
 * is not touched by the kernel.
 *
 * For SCTP, the port given in each socket address must be the same, or
 * sctp_connectx() will fail, setting errno to EINVAL.
 *
 * An application can use sctp_connectx to initiate an association with
 * an endpoint that is multi-homed.  Much like sctp_bindx() this call
 * allows a caller to specify multiple addresses at which a peer can be
 * reached.  The way the SCTP stack uses the list of addresses to set up
 * the association is implementation dependant.  This function only
 * specifies that the stack will try to make use of all the addresses in
 * the list when needed.
 *
 * Note that the list of addresses passed in is only used for setting up
 * the association.  It does not necessarily equal the set of addresses
 * the peer uses for the resulting association.  If the caller wants to
 * find out the set of peer addresses, it must use sctp_getpaddrs() to
 * retrieve them after the association has been set up.
 *
 * Basically do nothing but copying the addresses from user to kernel
 * land and invoking either sctp_connectx(). This is used for tunneling
 * the sctp_connectx() request through sctp_setsockopt() from userspace.
 *
 * We don't use copy_from_user() for optimization: we first do the
 * sanity checks (buffer size -fast- and access check-healthy
 * pointer); if all of those succeed, then we can alloc the memory
 * (expensive operation) needed to copy the data to kernel. Then we do
 * the copying without checking the user space area
 * (__copy_from_user()).
 *
 * On exit there is no need to do sockfd_put(), sys_setsockopt() does
 * it.
 *
 * sk        The sk of the socket
 * addrs     The pointer to the addresses in user land
 * addrssize Size of the addrs buffer
 *
 * Returns >=0 if ok, <0 errno code on error.
 */
SCTP_STATIC int __sctp_setsockopt_connectx(struct sock* sk,
				      struct sockaddr __user *addrs,
				      int addrs_size,
				      sctp_assoc_t *assoc_id)
{
	int err = 0;
	struct sockaddr *kaddrs;

	SCTP_DEBUG_PRINTK("%s - sk %p addrs %p addrs_size %d\n",
			  __func__, sk, addrs, addrs_size);

	if (unlikely(addrs_size <= 0))
		return -EINVAL;

	/* Check the user passed a healthy pointer.  */
	if (unlikely(!access_ok(VERIFY_READ, addrs, addrs_size)))
		return -EFAULT;

	/* Alloc space for the address array in kernel memory.  */
	kaddrs = kmalloc(addrs_size, GFP_KERNEL);
	if (unlikely(!kaddrs))
		return -ENOMEM;

	if (__copy_from_user(kaddrs, addrs, addrs_size)) {
		err = -EFAULT;
	} else {
		err = __sctp_connect(sk, kaddrs, addrs_size, assoc_id);
	}

	kfree(kaddrs);

	return err;
}

/*
 * This is an older interface.  It's kept for backward compatibility
 * to the option that doesn't provide association id.
 */
SCTP_STATIC int sctp_setsockopt_connectx_old(struct sock* sk,
				      struct sockaddr __user *addrs,
				      int addrs_size)
{
	return __sctp_setsockopt_connectx(sk, addrs, addrs_size, NULL);
}

/*
 * New interface for the API.  The since the API is done with a socket
 * option, to make it simple we feed back the association id is as a return
 * indication to the call.  Error is always negative and association id is
 * always positive.
 */
SCTP_STATIC int sctp_setsockopt_connectx(struct sock* sk,
				      struct sockaddr __user *addrs,
				      int addrs_size)
{
	sctp_assoc_t assoc_id = 0;
	int err = 0;

	err = __sctp_setsockopt_connectx(sk, addrs, addrs_size, &assoc_id);

	if (err)
		return err;
	else
		return assoc_id;
}

/*
 * New (hopefully final) interface for the API.
 * We use the sctp_getaddrs_old structure so that use-space library
 * can avoid any unnecessary allocations.   The only defferent part
 * is that we store the actual length of the address buffer into the
 * addrs_num structure member.  That way we can re-use the existing
 * code.
 */
SCTP_STATIC int sctp_getsockopt_connectx3(struct sock* sk, int len,
					char __user *optval,
					int __user *optlen)
{
	struct sctp_getaddrs_old param;
	sctp_assoc_t assoc_id = 0;
	int err = 0;

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

	if (copy_from_user(&param, optval, sizeof(param)))
		return -EFAULT;

	err = __sctp_setsockopt_connectx(sk,
			(struct sockaddr __user *)param.addrs,
			param.addr_num, &assoc_id);

	if (err == 0 || err == -EINPROGRESS) {
		if (copy_to_user(optval, &assoc_id, sizeof(assoc_id)))
			return -EFAULT;
		if (put_user(sizeof(assoc_id), optlen))
			return -EFAULT;
	}

	return err;
}

/* API 3.1.4 close() - UDP Style Syntax
 * Applications use close() to perform graceful shutdown (as described in
 * Section 10.1 of [SCTP]) on ALL the associations currently represented
 * by a UDP-style socket.
 *
 * The syntax is
 *
 *   ret = close(int sd);
 *
 *   sd      - the socket descriptor of the associations to be closed.
 *
 * To gracefully shutdown a specific association represented by the
 * UDP-style socket, an application should use the sendmsg() call,
 * passing no user data, but including the appropriate flag in the
 * ancillary data (see Section xxxx).
 *
 * If sd in the close() call is a branched-off socket representing only
 * one association, the shutdown is performed on that association only.
 *
 * 4.1.6 close() - TCP Style Syntax
 *
 * Applications use close() to gracefully close down an association.
 *
 * The syntax is:
 *
 *    int close(int sd);
 *
 *      sd      - the socket descriptor of the association to be closed.
 *
 * After an application calls close() on a socket descriptor, no further
 * socket operations will succeed on that descriptor.
 *
 * API 7.1.4 SO_LINGER
 *
 * An application using the TCP-style socket can use this option to
 * perform the SCTP ABORT primitive.  The linger option structure is:
 *
 *  struct  linger {
 *     int     l_onoff;                // option on/off
 *     int     l_linger;               // linger time
 * };
 *
 * To enable the option, set l_onoff to 1.  If the l_linger value is set
 * to 0, calling close() is the same as the ABORT primitive.  If the
 * value is set to a negative value, the setsockopt() call will return
 * an error.  If the value is set to a positive value linger_time, the
 * close() can be blocked for at most linger_time ms.  If the graceful
 * shutdown phase does not finish during this period, close() will
 * return but the graceful shutdown phase continues in the system.
 */
SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
{
	struct sctp_endpoint *ep;
	struct sctp_association *asoc;
	struct list_head *pos, *temp;

	SCTP_DEBUG_PRINTK("sctp_close(sk: 0x%p, timeout:%ld)\n", sk, timeout);

	sctp_lock_sock(sk);
	sk->sk_shutdown = SHUTDOWN_MASK;
	sk->sk_state = SCTP_SS_CLOSING;

	ep = sctp_sk(sk)->ep;

	/* Walk all associations on an endpoint.  */
	list_for_each_safe(pos, temp, &ep->asocs) {
		asoc = list_entry(pos, struct sctp_association, asocs);

		if (sctp_style(sk, TCP)) {
			/* A closed association can still be in the list if
			 * it belongs to a TCP-style listening socket that is
			 * not yet accepted. If so, free it. If not, send an
			 * ABORT or SHUTDOWN based on the linger options.
			 */
			if (sctp_state(asoc, CLOSED)) {
				sctp_unhash_established(asoc);
				sctp_association_free(asoc);
				continue;
			}
		}

		if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
			struct sctp_chunk *chunk;

			chunk = sctp_make_abort_user(asoc, NULL, 0);
			if (chunk)
				sctp_primitive_ABORT(asoc, chunk);
		} else
			sctp_primitive_SHUTDOWN(asoc, NULL);
	}

	/* Clean up any skbs sitting on the receive queue.  */
	sctp_queue_purge_ulpevents(&sk->sk_receive_queue);
	sctp_queue_purge_ulpevents(&sctp_sk(sk)->pd_lobby);

	/* On a TCP-style socket, block for at most linger_time if set. */
	if (sctp_style(sk, TCP) && timeout)
		sctp_wait_for_close(sk, timeout);

	/* This will run the backlog queue.  */
	sctp_release_sock(sk);

	/* Supposedly, no process has access to the socket, but
	 * the net layers still may.
	 */
	sctp_local_bh_disable();
	sctp_bh_lock_sock(sk);

	/* Hold the sock, since sk_common_release() will put sock_put()
	 * and we have just a little more cleanup.
	 */
	sock_hold(sk);
	sk_common_release(sk);

	sctp_bh_unlock_sock(sk);
	sctp_local_bh_enable();

	sock_put(sk);

	SCTP_DBG_OBJCNT_DEC(sock);
}

/* Handle EPIPE error. */
static int sctp_error(struct sock *sk, int flags, int err)
{
	if (err == -EPIPE)
		err = sock_error(sk) ? : -EPIPE;
	if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
		send_sig(SIGPIPE, current, 0);
	return err;
}

/* API 3.1.3 sendmsg() - UDP Style Syntax
 *
 * An application uses sendmsg() and recvmsg() calls to transmit data to
 * and receive data from its peer.
 *
 *  ssize_t sendmsg(int socket, const struct msghdr *message,
 *                  int flags);
 *
 *  socket  - the socket descriptor of the endpoint.
 *  message - pointer to the msghdr structure which contains a single
 *            user message and possibly some ancillary data.
 *
 *            See Section 5 for complete description of the data
 *            structures.
 *
 *  flags   - flags sent or received with the user message, see Section
 *            5 for complete description of the flags.
 *
 * Note:  This function could use a rewrite especially when explicit
 * connect support comes in.
 */
/* BUG:  We do not implement the equivalent of sk_stream_wait_memory(). */

SCTP_STATIC int sctp_msghdr_parse(const struct msghdr *, sctp_cmsgs_t *);

SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
			     struct msghdr *msg, size_t msg_len)
{
	struct sctp_sock *sp;
	struct sctp_endpoint *ep;
	struct sctp_association *new_asoc=NULL, *asoc=NULL;
	struct sctp_transport *transport, *chunk_tp;
	struct sctp_chunk *chunk;
	union sctp_addr to;
	struct sockaddr *msg_name = NULL;
	struct sctp_sndrcvinfo default_sinfo = { 0 };
	struct sctp_sndrcvinfo *sinfo;
	struct sctp_initmsg *sinit;
	sctp_assoc_t associd = 0;
	sctp_cmsgs_t cmsgs = { NULL };
	int err;
	sctp_scope_t scope;
	long timeo;
	__u16 sinfo_flags = 0;
	struct sctp_datamsg *datamsg;
	int msg_flags = msg->msg_flags;

	SCTP_DEBUG_PRINTK("sctp_sendmsg(sk: %p, msg: %p, msg_len: %zu)\n",
			  sk, msg, msg_len);

	err = 0;
	sp = sctp_sk(sk);
	ep = sp->ep;

	SCTP_DEBUG_PRINTK("Using endpoint: %p.\n", ep);

	/* We cannot send a message over a TCP-style listening socket. */
	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) {
		err = -EPIPE;
		goto out_nounlock;
	}

	/* Parse out the SCTP CMSGs.  */
	err = sctp_msghdr_parse(msg, &cmsgs);

	if (err) {
		SCTP_DEBUG_PRINTK("msghdr parse err = %x\n", err);
		goto out_nounlock;
	}

	/* Fetch the destination address for this packet.  This
	 * address only selects the association--it is not necessarily
	 * the address we will send to.
	 * For a peeled-off socket, msg_name is ignored.
	 */
	if (!sctp_style(sk, UDP_HIGH_BANDWIDTH) && msg->msg_name) {
		int msg_namelen = msg->msg_namelen;

		err = sctp_verify_addr(sk, (union sctp_addr *)msg->msg_name,
				       msg_namelen);
		if (err)
			return err;

		if (msg_namelen > sizeof(to))
			msg_namelen = sizeof(to);
		memcpy(&to, msg->msg_name, msg_namelen);
		msg_name = msg->msg_name;
	}

	sinfo = cmsgs.info;
	sinit = cmsgs.init;

	/* Did the user specify SNDRCVINFO?  */
	if (sinfo) {
		sinfo_flags = sinfo->sinfo_flags;
		associd = sinfo->sinfo_assoc_id;
	}

	SCTP_DEBUG_PRINTK("msg_len: %zu, sinfo_flags: 0x%x\n",
			  msg_len, sinfo_flags);

	/* SCTP_EOF or SCTP_ABORT cannot be set on a TCP-style socket. */
	if (sctp_style(sk, TCP) && (sinfo_flags & (SCTP_EOF | SCTP_ABORT))) {
		err = -EINVAL;
		goto out_nounlock;
	}

	/* If SCTP_EOF is set, no data can be sent. Disallow sending zero
	 * length messages when SCTP_EOF|SCTP_ABORT is not set.
	 * If SCTP_ABORT is set, the message length could be non zero with
	 * the msg_iov set to the user abort reason.
	 */
	if (((sinfo_flags & SCTP_EOF) && (msg_len > 0)) ||
	    (!(sinfo_flags & (SCTP_EOF|SCTP_ABORT)) && (msg_len == 0))) {
		err = -EINVAL;
		goto out_nounlock;
	}

	/* If SCTP_ADDR_OVER is set, there must be an address
	 * specified in msg_name.
	 */
	if ((sinfo_flags & SCTP_ADDR_OVER) && (!msg->msg_name)) {
		err = -EINVAL;
		goto out_nounlock;
	}

	transport = NULL;

	SCTP_DEBUG_PRINTK("About to look up association.\n");

	sctp_lock_sock(sk);

	/* If a msg_name has been specified, assume this is to be used.  */
	if (msg_name) {
		/* Look for a matching association on the endpoint. */
		asoc = sctp_endpoint_lookup_assoc(ep, &to, &transport);
		if (!asoc) {
			/* If we could not find a matching association on the
			 * endpoint, make sure that it is not a TCP-style
			 * socket that already has an association or there is
			 * no peeled-off association on another socket.
			 */
			if ((sctp_style(sk, TCP) &&
			     sctp_sstate(sk, ESTABLISHED)) ||
			    sctp_endpoint_is_peeled_off(ep, &to)) {
				err = -EADDRNOTAVAIL;
				goto out_unlock;
			}
		}
	} else {
		asoc = sctp_id2assoc(sk, associd);
		if (!asoc) {
			err = -EPIPE;
			goto out_unlock;
		}
	}

	if (asoc) {
		SCTP_DEBUG_PRINTK("Just looked up association: %p.\n", asoc);

		/* We cannot send a message on a TCP-style SCTP_SS_ESTABLISHED
		 * socket that has an association in CLOSED state. This can
		 * happen when an accepted socket has an association that is
		 * already CLOSED.
		 */
		if (sctp_state(asoc, CLOSED) && sctp_style(sk, TCP)) {
			err = -EPIPE;
			goto out_unlock;
		}

		if (sinfo_flags & SCTP_EOF) {
			SCTP_DEBUG_PRINTK("Shutting down association: %p\n",
					  asoc);
			sctp_primitive_SHUTDOWN(asoc, NULL);
			err = 0;
			goto out_unlock;
		}
		if (sinfo_flags & SCTP_ABORT) {

			chunk = sctp_make_abort_user(asoc, msg, msg_len);
			if (!chunk) {
				err = -ENOMEM;
				goto out_unlock;
			}

			SCTP_DEBUG_PRINTK("Aborting association: %p\n", asoc);
			sctp_primitive_ABORT(asoc, chunk);
			err = 0;
			goto out_unlock;
		}
	}

	/* Do we need to create the association?  */
	if (!asoc) {
		SCTP_DEBUG_PRINTK("There is no association yet.\n");

		if (sinfo_flags & (SCTP_EOF | SCTP_ABORT)) {
			err = -EINVAL;
			goto out_unlock;
		}

		/* Check for invalid stream against the stream counts,
		 * either the default or the user specified stream counts.
		 */
		if (sinfo) {
			if (!sinit || (sinit && !sinit->sinit_num_ostreams)) {
				/* Check against the defaults. */
				if (sinfo->sinfo_stream >=
				    sp->initmsg.sinit_num_ostreams) {
					err = -EINVAL;
					goto out_unlock;
				}
			} else {
				/* Check against the requested.  */
				if (sinfo->sinfo_stream >=
				    sinit->sinit_num_ostreams) {
					err = -EINVAL;
					goto out_unlock;
				}
			}
		}

		/*
		 * API 3.1.2 bind() - UDP Style Syntax
		 * If a bind() or sctp_bindx() is not called prior to a
		 * sendmsg() call that initiates a new association, the
		 * system picks an ephemeral port and will choose an address
		 * set equivalent to binding with a wildcard address.
		 */
		if (!ep->base.bind_addr.port) {
			if (sctp_autobind(sk)) {
				err = -EAGAIN;
				goto out_unlock;
			}
		} else {
			/*
			 * If an unprivileged user inherits a one-to-many
			 * style socket with open associations on a privileged
			 * port, it MAY be permitted to accept new associations,
			 * but it SHOULD NOT be permitted to open new
			 * associations.
			 */
			if (ep->base.bind_addr.port < PROT_SOCK &&
			    !capable(CAP_NET_BIND_SERVICE)) {
				err = -EACCES;
				goto out_unlock;
			}
		}

		scope = sctp_scope(&to);
		new_asoc = sctp_association_new(ep, sk, scope, GFP_KERNEL);
		if (!new_asoc) {
			err = -ENOMEM;
			goto out_unlock;
		}
		asoc = new_asoc;
		err = sctp_assoc_set_bind_addr_from_ep(asoc, scope, GFP_KERNEL);
		if (err < 0) {
			err = -ENOMEM;
			goto out_free;
		}

		/* If the SCTP_INIT ancillary …