net/sctp/protocol.c

/* SCTP kernel reference Implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001 Intel Corp.
 * Copyright (c) 2001 Nokia, Inc.
 * Copyright (c) 2001 La Monte H.P. Yarroll
 *
 * This file is part of the SCTP kernel reference Implementation
 *
 * Initialization/cleanup for SCTP protocol support.
 *
 * The SCTP reference 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.
 *
 * The SCTP reference 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>
 *    Karl Knutson <karl@athena.chicago.il.us>
 *    Jon Grimm <jgrimm@us.ibm.com>
 *    Sridhar Samudrala <sri@us.ibm.com>
 *    Daisy Chang <daisyc@us.ibm.com>
 *    Ardelle Fan <ardelle.fan@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/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/seq_file.h>
#include <net/protocol.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/route.h>
#include <net/sctp/sctp.h>
#include <net/addrconf.h>
#include <net/inet_common.h>
#include <net/inet_ecn.h>

/* Global data structures. */
struct sctp_globals sctp_globals __read_mostly;
struct proc_dir_entry	*proc_net_sctp;
DEFINE_SNMP_STAT(struct sctp_mib, sctp_statistics) __read_mostly;

struct idr sctp_assocs_id;
DEFINE_SPINLOCK(sctp_assocs_id_lock);

/* This is the global socket data structure used for responding to
 * the Out-of-the-blue (OOTB) packets.  A control sock will be created
 * for this socket at the initialization time.
 */
static struct socket *sctp_ctl_socket;

static struct sctp_pf *sctp_pf_inet6_specific;
static struct sctp_pf *sctp_pf_inet_specific;
static struct sctp_af *sctp_af_v4_specific;
static struct sctp_af *sctp_af_v6_specific;

kmem_cache_t *sctp_chunk_cachep __read_mostly;
kmem_cache_t *sctp_bucket_cachep __read_mostly;

/* Return the address of the control sock. */
struct sock *sctp_get_ctl_sock(void)
{
	return sctp_ctl_socket->sk;
}

/* Set up the proc fs entry for the SCTP protocol. */
static __init int sctp_proc_init(void)
{
	if (!proc_net_sctp) {
		struct proc_dir_entry *ent;
		ent = proc_mkdir("net/sctp", NULL);
		if (ent) {
			ent->owner = THIS_MODULE;
			proc_net_sctp = ent;
		} else
			goto out_nomem;
	}

	if (sctp_snmp_proc_init())
		goto out_nomem;	
	if (sctp_eps_proc_init())
		goto out_nomem;	
	if (sctp_assocs_proc_init())
		goto out_nomem;	

	return 0;

out_nomem:
	return -ENOMEM;
}

/* Clean up the proc fs entry for the SCTP protocol. 
 * Note: Do not make this __exit as it is used in the init error
 * path.
 */
static void sctp_proc_exit(void)
{
	sctp_snmp_proc_exit();
	sctp_eps_proc_exit();
	sctp_assocs_proc_exit();

	if (proc_net_sctp) {
		proc_net_sctp = NULL;
		remove_proc_entry("net/sctp", NULL);
	}
}

/* Private helper to extract ipv4 address and stash them in
 * the protocol structure.
 */
static void sctp_v4_copy_addrlist(struct list_head *addrlist,
				  struct net_device *dev)
{
	struct in_device *in_dev;
	struct in_ifaddr *ifa;
	struct sctp_sockaddr_entry *addr;

	rcu_read_lock();
	if ((in_dev = __in_dev_get_rcu(dev)) == NULL) {
		rcu_read_unlock();
		return;
	}

	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
		/* Add the address to the local list.  */
		addr = t_new(struct sctp_sockaddr_entry, GFP_ATOMIC);
		if (addr) {
			addr->a.v4.sin_family = AF_INET;
			addr->a.v4.sin_port = 0;
			addr->a.v4.sin_addr.s_addr = ifa->ifa_local;
			addr->a_h = addr->a;
			list_add_tail(&addr->list, addrlist);
		}
	}

	rcu_read_unlock();
}

/* Extract our IP addresses from the system and stash them in the
 * protocol structure.
 */
static void __sctp_get_local_addr_list(void)
{
	struct net_device *dev;
	struct list_head *pos;
	struct sctp_af *af;

	read_lock(&dev_base_lock);
	for (dev = dev_base; dev; dev = dev->next) {
		__list_for_each(pos, &sctp_address_families) {
			af = list_entry(pos, struct sctp_af, list);
			af->copy_addrlist(&sctp_local_addr_list, dev);
		}
	}
	read_unlock(&dev_base_lock);
}

static void sctp_get_local_addr_list(void)
{
	unsigned long flags;

	sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
	__sctp_get_local_addr_list();
	sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
}

/* Free the existing local addresses.  */
static void __sctp_free_local_addr_list(void)
{
	struct sctp_sockaddr_entry *addr;
	struct list_head *pos, *temp;

	list_for_each_safe(pos, temp, &sctp_local_addr_list) {
		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
		list_del(pos);
		kfree(addr);
	}
}

/* Free the existing local addresses.  */
static void sctp_free_local_addr_list(void)
{
	unsigned long flags;

	sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
	__sctp_free_local_addr_list();
	sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
}

/* Copy the local addresses which are valid for 'scope' into 'bp'.  */
int sctp_copy_local_addr_list(struct sctp_bind_addr *bp, sctp_scope_t scope,
			      gfp_t gfp, int copy_flags)
{
	struct sctp_sockaddr_entry *addr;
	int error = 0;
	struct list_head *pos;
	unsigned long flags;

	sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
	list_for_each(pos, &sctp_local_addr_list) {
		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
		if (sctp_in_scope(&addr->a_h, scope)) {
			/* Now that the address is in scope, check to see if
			 * the address type is really supported by the local
			 * sock as well as the remote peer.
			 */
			if ((((AF_INET == addr->a_h.sa.sa_family) &&
			      (copy_flags & SCTP_ADDR4_PEERSUPP))) ||
			    (((AF_INET6 == addr->a_h.sa.sa_family) &&
			      (copy_flags & SCTP_ADDR6_ALLOWED) &&
			      (copy_flags & SCTP_ADDR6_PEERSUPP)))) {
				error = sctp_add_bind_addr(bp, &addr->a, 1,
							   GFP_ATOMIC);
				if (error)
					goto end_copy;
			}
		}
	}

end_copy:
	sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
	return error;
}

/* Initialize a sctp_addr from in incoming skb.  */
static void sctp_v4_from_skb(union sctp_addr *addr, struct sk_buff *skb,
			     int is_saddr)
{
	void *from;
	__be16 *port;
	struct sctphdr *sh;

	port = &addr->v4.sin_port;
	addr->v4.sin_family = AF_INET;

	sh = (struct sctphdr *) skb->h.raw;
	if (is_saddr) {
		*port  = sh->source;
		from = &skb->nh.iph->saddr;
	} else {
		*port = sh->dest;
		from = &skb->nh.iph->daddr;
	}
	memcpy(&addr->v4.sin_addr.s_addr, from, sizeof(struct in_addr));
}

/* Initialize an sctp_addr from a socket. */
static void sctp_v4_from_sk(union sctp_addr *addr, struct sock *sk)
{
	addr->v4.sin_family = AF_INET;
	addr->v4.sin_port = inet_sk(sk)->num;
	addr->v4.sin_addr.s_addr = inet_sk(sk)->rcv_saddr;
}

/* Initialize sk->sk_rcv_saddr from sctp_addr. */
static void sctp_v4_to_sk_saddr(union sctp_addr *addr, struct sock *sk)
{
	inet_sk(sk)->rcv_saddr = addr->v4.sin_addr.s_addr;
}

/* Initialize sk->sk_daddr from sctp_addr. */
static void sctp_v4_to_sk_daddr(union sctp_addr *addr, struct sock *sk)
{
	inet_sk(sk)->daddr = addr->v4.sin_addr.s_addr;
}

/* Initialize a sctp_addr from an address parameter. */
static void sctp_v4_from_addr_param(union sctp_addr *addr,
				    union sctp_addr_param *param,
				    __be16 port, int iif)
{
	addr->v4.sin_family = AF_INET;
	addr->v4.sin_port = port;
	addr->v4.sin_addr.s_addr = param->v4.addr.s_addr;
}

/* Initialize an address parameter from a sctp_addr and return the length
 * of the address parameter.
 */
static int sctp_v4_to_addr_param(const union sctp_addr *addr,
				 union sctp_addr_param *param)
{
	int length = sizeof(sctp_ipv4addr_param_t);

	param->v4.param_hdr.type = SCTP_PARAM_IPV4_ADDRESS;
	param->v4.param_hdr.length = htons(length);
	param->v4.addr.s_addr = addr->v4.sin_addr.s_addr;	

	return length;
}

/* Initialize a sctp_addr from a dst_entry. */
static void sctp_v4_dst_saddr(union sctp_addr *saddr, struct dst_entry *dst,
			      __be16 port)
{
	struct rtable *rt = (struct rtable *)dst;
	saddr->v4.sin_family = AF_INET;
	saddr->v4.sin_port = port;
	saddr->v4.sin_addr.s_addr = rt->rt_src;
}

/* Compare two addresses exactly. */
static int sctp_v4_cmp_addr(const union sctp_addr *addr1,
			    const union sctp_addr *addr2)
{
	if (addr1->sa.sa_family != addr2->sa.sa_family)
		return 0;
	if (addr1->v4.sin_port != addr2->v4.sin_port)
		return 0;
	if (addr1->v4.sin_addr.s_addr != addr2->v4.sin_addr.s_addr)
		return 0;

	return 1;
}

/* Initialize addr struct to INADDR_ANY. */
static void sctp_v4_inaddr_any(union sctp_addr *addr, unsigned short port)
{
	addr->v4.sin_family = AF_INET;
	addr->v4.sin_addr.s_addr = INADDR_ANY;
	addr->v4.sin_port = port;
}

/* Is this a wildcard address? */
static int sctp_v4_is_any(const union sctp_addr *addr)
{
	return INADDR_ANY == addr->v4.sin_addr.s_addr;
}

/* This function checks if the address is a valid address to be used for
 * SCTP binding.
 *
 * Output:
 * Return 0 - If the address is a non-unicast or an illegal address.
 * Return 1 - If the address is a unicast.
 */
static int sctp_v4_addr_valid(union sctp_addr *addr,
			      struct sctp_sock *sp,
			      const struct sk_buff *skb)
{
	/* Is this a non-unicast address or a unusable SCTP address? */
	if (IS_IPV4_UNUSABLE_ADDRESS(&addr->v4.sin_addr.s_addr))
		return 0;

 	/* Is this a broadcast address? */
 	if (skb && ((struct rtable *)skb->dst)->rt_flags & RTCF_BROADCAST)
 		return 0;

	return 1;
}

/* Should this be available for binding?   */
static int sctp_v4_available(union sctp_addr *addr, struct sctp_sock *sp)
{
	int ret = inet_addr_type(addr->v4.sin_addr.s_addr);


	if (addr->v4.sin_addr.s_addr != INADDR_ANY &&
	   ret != RTN_LOCAL &&
	   !sp->inet.freebind &&
	   !sysctl_ip_nonlocal_bind)
		return 0;

	return 1;
}

/* Checking the loopback, private and other address scopes as defined in
 * RFC 1918.   The IPv4 scoping is based on the draft for SCTP IPv4
 * scoping <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
 *
 * Level 0 - unusable SCTP addresses
 * Level 1 - loopback address
 * Level 2 - link-local addresses
 * Level 3 - private addresses.
 * Level 4 - global addresses
 * For INIT and INIT-ACK address list, let L be the level of
 * of requested destination address, sender and receiver
 * SHOULD include all of its addresses with level greater
 * than or equal to L.
 */
static sctp_scope_t sctp_v4_scope(union sctp_addr *addr)
{
	sctp_scope_t retval;

	/* Should IPv4 scoping be a sysctl configurable option
	 * so users can turn it off (default on) for certain
	 * unconventional networking environments?
	 */

	/* Check for unusable SCTP addresses. */
	if (IS_IPV4_UNUSABLE_ADDRESS(&addr->v4.sin_addr.s_addr)) {
		retval =  SCTP_SCOPE_UNUSABLE;
	} else if (LOOPBACK(addr->v4.sin_addr.s_addr)) {
		retval = SCTP_SCOPE_LOOPBACK;
	} else if (IS_IPV4_LINK_ADDRESS(&addr->v4.sin_addr.s_addr)) {
		retval = SCTP_SCOPE_LINK;
	} else if (IS_IPV4_PRIVATE_ADDRESS(&addr->v4.sin_addr.s_addr)) {
		retval = SCTP_SCOPE_PRIVATE;
	} else {
		retval = SCTP_SCOPE_GLOBAL;
	}

	return retval;
}

/* Returns a valid dst cache entry for the given source and destination ip
 * addresses. If an association is passed, trys to get a dst entry with a
 * source address that matches an address in the bind address list.
 */
static struct dst_entry *sctp_v4_get_dst(struct sctp_association *asoc,
					 union sctp_addr *daddr,
					 union sctp_addr *saddr)
{
	struct rtable *rt;
	struct flowi fl;
	struct sctp_bind_addr *bp;
	rwlock_t *addr_lock;
	struct sctp_sockaddr_entry *laddr;
	struct list_head *pos;
	struct dst_entry *dst = NULL;
	union sctp_addr dst_saddr;

	memset(&fl, 0x0, sizeof(struct flowi));
	fl.fl4_dst  = daddr->v4.sin_addr.s_addr;
	fl.proto = IPPROTO_SCTP;
	if (asoc) {
		fl.fl4_tos = RT_CONN_FLAGS(asoc->base.sk);
		fl.oif = asoc->base.sk->sk_bound_dev_if;
	}
	if (saddr)
		fl.fl4_src = saddr->v4.sin_addr.s_addr;

	SCTP_DEBUG_PRINTK("%s: DST:%u.%u.%u.%u, SRC:%u.%u.%u.%u - ",
			  __FUNCTION__, NIPQUAD(fl.fl4_dst),
			  NIPQUAD(fl.fl4_src));

	if (!ip_route_output_key(&rt, &fl)) {
		dst = &rt->u.dst;
	}

	/* If there is no association or if a source address is passed, no
	 * more validation is required.
	 */
	if (!asoc || saddr)
		goto out;

	bp = &asoc->base.bind_addr;
	addr_lock = &asoc->base.addr_lock;

	if (dst) {
		/* Walk through the bind address list and look for a bind
		 * address that matches the source address of the returned dst.
		 */
		sctp_read_lock(addr_lock);
		list_for_each(pos, &bp->address_list) {
			laddr = list_entry(pos, struct sctp_sockaddr_entry,
					   list);
			if (!laddr->use_as_src)
				continue;
			sctp_v4_dst_saddr(&dst_saddr, dst, htons(bp->port));
			if (sctp_v4_cmp_addr(&dst_saddr, &laddr->a))
				goto out_unlock;
		}
		sctp_read_unlock(addr_lock);

		/* None of the bound addresses match the source address of the
		 * dst. So release it.
		 */
		dst_release(dst);
		dst = NULL;
	}

	/* Walk through the bind address list and try to get a dst that
	 * matches a bind address as the source address.
	 */
	sctp_read_lock(addr_lock);
	list_for_each(pos, &bp->address_list) {
		laddr = list_entry(pos, struct sctp_sockaddr_entry, list);

		if ((laddr->use_as_src) &&
		    (AF_INET == laddr->a_h.sa.sa_family)) {
			fl.fl4_src = laddr->a_h.v4.sin_addr.s_addr;
			if (!ip_route_output_key(&rt, &fl)) {
				dst = &rt->u.dst;
				goto out_unlock;
			}
		}
	}

out_unlock:
	sctp_read_unlock(addr_lock);
out:
	if (dst)
		SCTP_DEBUG_PRINTK("rt_dst:%u.%u.%u.%u, rt_src:%u.%u.%u.%u\n",
			  	  NIPQUAD(rt->rt_dst), NIPQUAD(rt->rt_src));
	else
		SCTP_DEBUG_PRINTK("NO ROUTE\n");

	return dst;
}

/* For v4, the source address is cached in the route entry(dst). So no need
 * to cache it separately and hence this is an empty routine.
 */
static void sctp_v4_get_saddr(struct sctp_association *asoc,
			      struct dst_entry *dst,
			      union sctp_addr *daddr,
			      union sctp_addr *saddr)
{
	struct rtable *rt = (struct rtable *)dst;

	if (!asoc)
		return;

	if (rt) {
		saddr->v4.sin_family = AF_INET;
		saddr->v4.sin_port = asoc->base.bind_addr.port;  
		saddr->v4.sin_addr.s_addr = rt->rt_src; 
	}
}

/* What interface did this skb arrive on? */
static int sctp_v4_skb_iif(const struct sk_buff *skb)
{
     	return ((struct rtable *)skb->dst)->rt_iif;
}

/* Was this packet marked by Explicit Congestion Notification? */
static int sctp_v4_is_ce(const struct sk_buff *skb)
{
	return INET_ECN_is_ce(skb->nh.iph->tos);
}

/* Create and initialize a new sk for the socket returned by accept(). */
static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
					     struct sctp_association *asoc)
{
	struct inet_sock *inet = inet_sk(sk);
	struct inet_sock *newinet;
	struct sock *newsk = sk_alloc(PF_INET, GFP_KERNEL, sk->sk_prot, 1);

	if (!newsk)
		goto out;

	sock_init_data(NULL, newsk);

	newsk->sk_type = SOCK_STREAM;

	newsk->sk_no_check = sk->sk_no_check;
	newsk->sk_reuse = sk->sk_reuse;
	newsk->sk_shutdown = sk->sk_shutdown;

	newsk->sk_destruct = inet_sock_destruct;
	newsk->sk_family = PF_INET;
	newsk->sk_protocol = IPPROTO_SCTP;
	newsk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
	sock_reset_flag(newsk, SOCK_ZAPPED);

	newinet = inet_sk(newsk);

	/* Initialize sk's sport, dport, rcv_saddr and daddr for
	 * getsockname() and getpeername()
	 */
	newinet->sport = inet->sport;
	newinet->saddr = inet->saddr;
	newinet->rcv_saddr = inet->rcv_saddr;
	newinet->dport = htons(asoc->peer.port);
	newinet->daddr = asoc->peer.primary_addr.v4.sin_addr.s_addr;
	newinet->pmtudisc = inet->pmtudisc;
      	newinet->id = asoc->next_tsn ^ jiffies;

	newinet->uc_ttl = -1;
	newinet->mc_loop = 1;
	newinet->mc_ttl = 1;
	newinet->mc_index = 0;
	newinet->mc_list = NULL;

	sk_refcnt_debug_inc(newsk);

	if (newsk->sk_prot->init(newsk)) {
		sk_common_release(newsk);
		newsk = NULL;
	}

out:
	return newsk;
}

/* Map address, empty for v4 family */
static void sctp_v4_addr_v4map(struct sctp_sock *sp, union sctp_addr *addr)
{
	/* Empty */
}

/* Dump the v4 addr to the seq file. */
static void sctp_v4_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
{
	seq_printf(seq, "%d.%d.%d.%d ", NIPQUAD(addr->v4.sin_addr));
}

/* Event handler for inet address addition/deletion events.
 * Basically, whenever there is an event, we re-build our local address list.
 */
int sctp_inetaddr_event(struct notifier_block *this, unsigned long ev,
                        void *ptr)
{
	unsigned long flags;

	sctp_spin_lock_irqsave(&sctp_local_addr_lock, flags);
	__sctp_free_local_addr_list();
	__sctp_get_local_addr_list();
	sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);

	return NOTIFY_DONE;
}

/*
 * Initialize the control inode/socket with a control endpoint data
 * structure.  This endpoint is reserved exclusively for the OOTB processing.
 */
static int sctp_ctl_sock_init(void)
{
	int err;
	sa_family_t family;

	if (sctp_get_pf_specific(PF_INET6))
		family = PF_INET6;
	else
		family = PF_INET;

	err = sock_create_kern(family, SOCK_SEQPACKET, IPPROTO_SCTP,
			       &sctp_ctl_socket);
	if (err < 0) {
		printk(KERN_ERR
		       "SCTP: Failed to create the SCTP control socket.\n");
		return err;
	}
	sctp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
	inet_sk(sctp_ctl_socket->sk)->uc_ttl = -1;

	return 0;
}

/* Register address family specific functions. */
int sctp_register_af(struct sctp_af *af)
{
	switch (af->sa_family) {
	case AF_INET:
		if (sctp_af_v4_specific)
			return 0;
		sctp_af_v4_specific = af;
		break;
	case AF_INET6:
		if (sctp_af_v6_specific)
			return 0;
		sctp_af_v6_specific = af;
		break;
	default:
		return 0;
	}

	INIT_LIST_HEAD(&af->list);
	list_add_tail(&af->list, &sctp_address_families);
	return 1;
}

/* Get the table of functions for manipulating a particular address
 * family.
 */
struct sctp_af *sctp_get_af_specific(sa_family_t family)
{
	switch (family) {
	case AF_INET:
		return sctp_af_v4_specific;
	case AF_INET6:
		return sctp_af_v6_specific;
	default:
		return NULL;
	}
}

/* Common code to initialize a AF_INET msg_name. */
static void sctp_inet_msgname(char *msgname, int *addr_len)
{
	struct sockaddr_in *sin;

	sin = (struct sockaddr_in *)msgname;
	*addr_len = sizeof(struct sockaddr_in);
	sin->sin_family = AF_INET;
	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
}

/* Copy the primary address of the peer primary address as the msg_name. */
static void sctp_inet_event_msgname(struct sctp_ulpevent *event, char *msgname,
				    int *addr_len)
{
	struct sockaddr_in *sin, *sinfrom;

	if (msgname) {
		struct sctp_association *asoc;

		asoc = event->asoc;
		sctp_inet_msgname(msgname, addr_len);
		sin = (struct sockaddr_in *)msgname;
		sinfrom = &asoc->peer.primary_addr.v4;
		sin->sin_port = htons(asoc->peer.port);
		sin->sin_addr.s_addr = sinfrom->sin_addr.s_addr;
	}
}

/* Initialize and copy out a msgname from an inbound skb. */
static void sctp_inet_skb_msgname(struct sk_buff *skb, char *msgname, int *len)
{
	struct sctphdr *sh;
	struct sockaddr_in *sin;

	if (msgname) {
		sctp_inet_msgname(msgname, len);
		sin = (struct sockaddr_in *)msgname;
		sh = (struct sctphdr *)skb->h.raw;
		sin->sin_port = sh->source;
		sin->sin_addr.s_addr = skb->nh.iph->saddr;
	}
}

/* Do we support this AF? */
static int sctp_inet_af_supported(sa_family_t family, struct sctp_sock *sp)
{
	/* PF_INET only supports AF_INET addresses. */
	return (AF_INET == family);
}

/* Address matching with wildcards allowed. */
static int sctp_inet_cmp_addr(const union sctp_addr *addr1,
			      const union sctp_addr *addr2,
			      struct sctp_sock *opt)
{
	/* PF_INET only supports AF_INET addresses. */
	if (addr1->sa.sa_family != addr2->sa.sa_family)
		return 0;
	if (INADDR_ANY == addr1->v4.sin_addr.s_addr ||
	    INADDR_ANY == addr2->v4.sin_addr.s_addr)
		return 1;
	if (addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr)
		return 1;

	return 0;
}

/* Verify that provided sockaddr looks bindable.  Common verification has
 * already been taken care of.
 */
static int sctp_inet_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
	return sctp_v4_available(addr, opt);
}

/* Verify that sockaddr looks sendable.  Common verification has already
 * been taken care of.
 */
static int sctp_inet_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
	return 1;
}

/* Fill in Supported Address Type information for INIT and INIT-ACK
 * chunks.  Returns number of addresses supported.
 */
static int sctp_inet_supported_addrs(const struct sctp_sock *opt,
				     __u16 *types)
{
	types[0] = SCTP_PARAM_IPV4_ADDRESS;
	return 1;
}

/* Wrapper routine that calls the ip transmit routine. */
static inline int sctp_v4_xmit(struct sk_buff *skb,
			       struct sctp_transport *transport, int ipfragok)
{
	SCTP_DEBUG_PRINTK("%s: skb:%p, len:%d, "
			  "src:%u.%u.%u.%u, dst:%u.%u.%u.%u\n",
			  __FUNCTION__, skb, skb->len,
			  NIPQUAD(((struct rtable *)skb->dst)->rt_src),
			  NIPQUAD(((struct rtable *)skb->dst)->rt_dst));

	SCTP_INC_STATS(SCTP_MIB_OUTSCTPPACKS);
	return ip_queue_xmit(skb, skb->sk, ipfragok);
}

static struct sctp_af sctp_ipv4_specific;

static struct sctp_pf sctp_pf_inet = {
	.event_msgname = sctp_inet_event_msgname,
	.skb_msgname   = sctp_inet_skb_msgname,
	.af_supported  = sctp_inet_af_supported,
	.cmp_addr      = sctp_inet_cmp_addr,
	.bind_verify   = sctp_inet_bind_verify,
	.send_verify   = sctp_inet_send_verify,
	.supported_addrs = sctp_inet_supported_addrs,
	.create_accept_sk = sctp_v4_create_accept_sk,
	.addr_v4map	= sctp_v4_addr_v4map,
	.af            = &sctp_ipv4_specific,
};

/* Notifier for inetaddr addition/deletion events.  */
static struct notifier_block sctp_inetaddr_notifier = {
	.notifier_call = sctp_inetaddr_event,
};

/* Socket operations.  */
static const struct proto_ops inet_seqpacket_ops = {
	.family		   = PF_INET,
	.owner		   = THIS_MODULE,
	.release	   = inet_release,	/* Needs to be wrapped... */
	.bind		   = inet_bind,
	.connect	   = inet_dgram_connect,
	.socketpair	   = sock_no_socketpair,
	.accept		   = inet_accept,
	.getname	   = inet_getname,	/* Semantics are different.  */
	.poll		   = sctp_poll,
	.ioctl		   = inet_ioctl,
	.listen		   = sctp_inet_listen,
	.shutdown	   = inet_shutdown,	/* Looks harmless.  */
	.setsockopt	   = sock_common_setsockopt, /* IP_SOL IP_OPTION is a problem */
	.getsockopt	   = sock_common_getsockopt,
	.sendmsg	   = inet_sendmsg,
	.recvmsg	   = sock_common_recvmsg,
	.mmap		   = sock_no_mmap,
	.sendpage	   = sock_no_sendpage,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_sock_common_setsockopt,
	.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

/* Registration with AF_INET family.  */
static struct inet_protosw sctp_seqpacket_protosw = {
	.type       = SOCK_SEQPACKET,
	.protocol   = IPPROTO_SCTP,
	.prot       = &sctp_prot,
	.ops        = &inet_seqpacket_ops,
	.capability = -1,
	.no_check   = 0,
	.flags      = SCTP_PROTOSW_FLAG
};
static struct inet_protosw sctp_stream_protosw = {
	.type       = SOCK_STREAM,
	.protocol   = IPPROTO_SCTP,
	.prot       = &sctp_prot,
	.ops        = &inet_seqpacket_ops,
	.capability = -1,
	.no_check   = 0,
	.flags      = SCTP_PROTOSW_FLAG
};

/* Register with IP layer.  */
static struct net_protocol sctp_protocol = {
	.handler     = sctp_rcv,
	.err_handler = sctp_v4_err,
	.no_policy   = 1,
};

/* IPv4 address related functions.  */
static struct sctp_af sctp_ipv4_specific = {
	.sa_family	   = AF_INET,
	.sctp_xmit	   = sctp_v4_xmit,
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.get_dst	   = sctp_v4_get_dst,
	.get_saddr	   = sctp_v4_get_saddr,
	.copy_addrlist	   = sctp_v4_copy_addrlist,
	.from_skb	   = sctp_v4_from_skb,
	.from_sk	   = sctp_v4_from_sk,
	.to_sk_saddr	   = sctp_v4_to_sk_saddr,
	.to_sk_daddr	   = sctp_v4_to_sk_daddr,
	.from_addr_param   = sctp_v4_from_addr_param,
	.to_addr_param	   = sctp_v4_to_addr_param,
	.dst_saddr	   = sctp_v4_dst_saddr,
	.cmp_addr	   = sctp_v4_cmp_addr,
	.addr_valid	   = sctp_v4_addr_valid,
	.inaddr_any	   = sctp_v4_inaddr_any,
	.is_any		   = sctp_v4_is_any,
	.available	   = sctp_v4_available,
	.scope		   = sctp_v4_scope,
	.skb_iif	   = sctp_v4_skb_iif,
	.is_ce		   = sctp_v4_is_ce,
	.seq_dump_addr	   = sctp_v4_seq_dump_addr,
	.net_header_len	   = sizeof(struct iphdr),
	.sockaddr_len	   = sizeof(struct sockaddr_in),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
#endif
};

struct sctp_pf *sctp_get_pf_specific(sa_family_t family) {

	switch (family) {
	case PF_INET:
		return sctp_pf_inet_specific;
	case PF_INET6:
		return sctp_pf_inet6_specific;
	default:
		return NULL;
	}
}

/* Register the PF specific function table.  */
int sctp_register_pf(struct sctp_pf *pf, sa_family_t family)
{
	switch (family) {
	case PF_INET:
		if (sctp_pf_inet_specific)
			return 0;
		sctp_pf_inet_specific = pf;
		break;
	case PF_INET6:
		if (sctp_pf_inet6_specific)
			return 0;
		sctp_pf_inet6_specific = pf;
		break;
	default:
		return 0;
	}
	return 1;
}

static int __init init_sctp_mibs(void)
{
	sctp_statistics[0] = alloc_percpu(struct sctp_mib);
	if (!sctp_statistics[0])
		return -ENOMEM;
	sctp_statistics[1] = alloc_percpu(struct sctp_mib);
	if (!sctp_statistics[1]) {
		free_percpu(sctp_statistics[0]);
		return -ENOMEM;
	}
	return 0;

}

static void cleanup_sctp_mibs(void)
{
	free_percpu(sctp_statistics[0]);
	free_percpu(sctp_statistics[1]);
}

/* Initialize the universe into something sensible.  */
SCTP_STATIC __init int sctp_init(void)
{
	int i;
	int status = -EINVAL;
	unsigned long goal;
	int order;

	/* SCTP_DEBUG sanity check. */
	if (!sctp_sanity_check())
		goto out;

	status = proto_register(&sctp_prot, 1);
	if (status)
		goto out;

	/* Add SCTP to inet_protos hash table.  */
	status = -EAGAIN;
	if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
		goto err_add_protocol;

	/* Add SCTP(TCP and UDP style) to inetsw linked list.  */
	inet_register_protosw(&sctp_seqpacket_protosw);
	inet_register_protosw(&sctp_stream_protosw);

	/* Allocate a cache pools. */
	status = -ENOBUFS;
	sctp_bucket_cachep = kmem_cache_create("sctp_bind_bucket",
					       sizeof(struct sctp_bind_bucket),
					       0, SLAB_HWCACHE_ALIGN,
					       NULL, NULL);

	if (!sctp_bucket_cachep)
		goto err_bucket_cachep;

	sctp_chunk_cachep = kmem_cache_create("sctp_chunk",
					       sizeof(struct sctp_chunk),
					       0, SLAB_HWCACHE_ALIGN,
					       NULL, NULL);
	if (!sctp_chunk_cachep)
		goto err_chunk_cachep;

	/* Allocate and initialise sctp mibs.  */
	status = init_sctp_mibs();
	if (status)
		goto err_init_mibs;

	/* Initialize proc fs directory.  */
	status = sctp_proc_init();
	if (status)
		goto err_init_proc;

	/* Initialize object count debugging.  */
	sctp_dbg_objcnt_init();

	/* Initialize the SCTP specific PF functions. */
	sctp_register_pf(&sctp_pf_inet, PF_INET);
	/*
	 * 14. Suggested SCTP Protocol Parameter Values
	 */
	/* The following protocol parameters are RECOMMENDED:  */
	/* RTO.Initial              - 3  seconds */
	sctp_rto_initial		= SCTP_RTO_INITIAL;
	/* RTO.Min                  - 1  second */
	sctp_rto_min	 		= SCTP_RTO_MIN;
	/* RTO.Max                 -  60 seconds */
	sctp_rto_max 			= SCTP_RTO_MAX;
	/* RTO.Alpha                - 1/8 */
	sctp_rto_alpha	        	= SCTP_RTO_ALPHA;
	/* RTO.Beta                 - 1/4 */
	sctp_rto_beta			= SCTP_RTO_BETA;

	/* Valid.Cookie.Life        - 60  seconds */
	sctp_valid_cookie_life		= SCTP_DEFAULT_COOKIE_LIFE;

	/* Whether Cookie Preservative is enabled(1) or not(0) */
	sctp_cookie_preserve_enable 	= 1;

	/* Max.Burst		    - 4 */
	sctp_max_burst 			= SCTP_MAX_BURST;

	/* Association.Max.Retrans  - 10 attempts
	 * Path.Max.Retrans         - 5  attempts (per destination address)
	 * Max.Init.Retransmits     - 8  attempts
	 */
	sctp_max_retrans_association 	= 10;
	sctp_max_retrans_path		= 5;
	sctp_max_retrans_init		= 8;

	/* Sendbuffer growth	    - do per-socket accounting */
	sctp_sndbuf_policy		= 0;

	/* Rcvbuffer growth	    - do per-socket accounting */
	sctp_rcvbuf_policy		= 0;

	/* HB.interval              - 30 seconds */
	sctp_hb_interval		= SCTP_DEFAULT_TIMEOUT_HEARTBEAT;

	/* delayed SACK timeout */
	sctp_sack_timeout		= SCTP_DEFAULT_TIMEOUT_SACK;

	/* Implementation specific variables. */

	/* Initialize default stream count setup information. */
	sctp_max_instreams    		= SCTP_DEFAULT_INSTREAMS;
	sctp_max_outstreams   		= SCTP_DEFAULT_OUTSTREAMS;

	/* Initialize handle used for association ids. */
	idr_init(&sctp_assocs_id);

	/* Size and allocate the association hash table.
	 * The methodology is similar to that of the tcp hash tables.
	 */
	if (num_physpages >= (128 * 1024))
		goal = num_physpages >> (22 - PAGE_SHIFT);
	else
		goal = num_physpages >> (24 - PAGE_SHIFT);

	for (order = 0; (1UL << order) < goal; order++)
		;

	do {
		sctp_assoc_hashsize = (1UL << order) * PAGE_SIZE /
					sizeof(struct sctp_hashbucket);
		if ((sctp_assoc_hashsize > (64 * 1024)) && order > 0)
			continue;
		sctp_assoc_hashtable = (struct sctp_hashbucket *)
					__get_free_pages(GFP_ATOMIC, order);
	} while (!sctp_assoc_hashtable && --order > 0);
	if (!sctp_assoc_hashtable) {
		printk(KERN_ERR "SCTP: Failed association hash alloc.\n");
		status = -ENOMEM;
		goto err_ahash_alloc;
	}
	for (i = 0; i < sctp_assoc_hashsize; i++) {
		rwlock_init(&sctp_assoc_hashtable[i].lock);
		sctp_assoc_hashtable[i].chain = NULL;
	}

	/* Allocate and initialize the endpoint hash table.  */
	sctp_ep_hashsize = 64;
	sctp_ep_hashtable = (struct sctp_hashbucket *)
		kmalloc(64 * sizeof(struct sctp_hashbucket), GFP_KERNEL);
	if (!sctp_ep_hashtable) {
		printk(KERN_ERR "SCTP: Failed endpoint_hash alloc.\n");
		status = -ENOMEM;
		goto err_ehash_alloc;
	}
	for (i = 0; i < sctp_ep_hashsize; i++) {
		rwlock_init(&sctp_ep_hashtable[i].lock);
		sctp_ep_hashtable[i].chain = NULL;
	}

	/* Allocate and initialize the SCTP port hash table.  */
	do {
		sctp_port_hashsize = (1UL << order) * PAGE_SIZE /
					sizeof(struct sctp_bind_hashbucket);
		if ((sctp_port_hashsize > (64 * 1024)) && order > 0)
			continue;
		sctp_port_hashtable = (struct sctp_bind_hashbucket *)
					__get_free_pages(GFP_ATOMIC, order);
	} while (!sctp_port_hashtable && --order > 0);
	if (!sctp_port_hashtable) {
		printk(KERN_ERR "SCTP: Failed bind hash alloc.");
		status = -ENOMEM;
		goto err_bhash_alloc;
	}
	for (i = 0; i < sctp_port_hashsize; i++) {
		spin_lock_init(&sctp_port_hashtable[i].lock);
		sctp_port_hashtable[i].chain = NULL;
	}

	spin_lock_init(&sctp_port_alloc_lock);
	sctp_port_rover = sysctl_local_port_range[0] - 1;

	printk(KERN_INFO "SCTP: Hash tables configured "
			 "(established %d bind %d)\n",
		sctp_assoc_hashsize, sctp_port_hashsize);

	/* Disable ADDIP by default. */
	sctp_addip_enable = 0;

	/* Enable PR-SCTP by default. */
	sctp_prsctp_enable = 1;

	sctp_sysctl_register();

	INIT_LIST_HEAD(&sctp_address_families);
	sctp_register_af(&sctp_ipv4_specific);

	status = sctp_v6_init();
	if (status)
		goto err_v6_init;

	/* Initialize the control inode/socket for handling OOTB packets.  */
	if ((status = sctp_ctl_sock_init())) {
		printk (KERN_ERR
			"SCTP: Failed to initialize the SCTP control sock.\n");
		goto err_ctl_sock_init;
	}

	/* Initialize the local address list. */
	INIT_LIST_HEAD(&sctp_local_addr_list);
	spin_lock_init(&sctp_local_addr_lock);

	/* Register notifier for inet address additions/deletions. */
	register_inetaddr_notifier(&sctp_inetaddr_notifier);

	sctp_get_local_addr_list();

	__unsafe(THIS_MODULE);
	status = 0;
out:
	return status;
err_ctl_sock_init:
	sctp_v6_exit();
err_v6_init:
	sctp_sysctl_unregister();
	list_del(&sctp_ipv4_specific.list);
	free_pages((unsigned long)sctp_port_hashtable,
		   get_order(sctp_port_hashsize *
			     sizeof(struct sctp_bind_hashbucket)));
err_bhash_alloc:
	kfree(sctp_ep_hashtable);
err_ehash_alloc:
	free_pages((unsigned long)sctp_assoc_hashtable,
		   get_order(sctp_assoc_hashsize *
			     sizeof(struct sctp_hashbucket)));
err_ahash_alloc:
	sctp_dbg_objcnt_exit();
err_init_proc:
	sctp_proc_exit();
	cleanup_sctp_mibs();
err_init_mibs:
	kmem_cache_destroy(sctp_chunk_cachep);
err_chunk_cachep:
	kmem_cache_destroy(sctp_bucket_cachep);
err_bucket_cachep:
	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
	inet_unregister_protosw(&sctp_seqpacket_protosw);
	inet_unregister_protosw(&sctp_stream_protosw);
err_add_protocol:
	proto_unregister(&sctp_prot);
	goto out;
}

/* Exit handler for the SCTP protocol.  */
SCTP_STATIC __exit void sctp_exit(void)
{
	/* BUG.  This should probably do something useful like clean
	 * up all the remaining associations and all that memory.
	 */

	/* Unregister notifier for inet address additions/deletions. */
	unregister_inetaddr_notifier(&sctp_inetaddr_notifier);

	/* Free the local address list.  */
	sctp_free_local_addr_list();

	/* Free the control endpoint.  */
	sock_release(sctp_ctl_socket);

	sctp_v6_exit();
	sctp_sysctl_unregister();
	list_del(&sctp_ipv4_specific.list);

	free_pages((unsigned long)sctp_assoc_hashtable,
		   get_order(sctp_assoc_hashsize *
			     sizeof(struct sctp_hashbucket)));
	kfree(sctp_ep_hashtable);
	free_pages((unsigned long)sctp_port_hashtable,
		   get_order(sctp_port_hashsize *
			     sizeof(struct sctp_bind_hashbucket)));

	kmem_cache_destroy(sctp_chunk_cachep);
	kmem_cache_destroy(sctp_bucket_cachep);

	sctp_dbg_objcnt_exit();
	sctp_proc_exit();
	cleanup_sctp_mibs();

	inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
	inet_unregister_protosw(&sctp_seqpacket_protosw);
	inet_unregister_protosw(&sctp_stream_protosw);
	proto_unregister(&sctp_prot);
}

module_init(sctp_init);
module_exit(sctp_exit);

/*
 * __stringify doesn't likes enums, so use IPPROTO_SCTP value (132) directly.
 */
MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-proto-132");
MODULE_AUTHOR("Linux Kernel SCTP developers <lksctp-developers@lists.sourceforge.net>");
MODULE_DESCRIPTION("Support for the SCTP protocol (RFC2960)");
MODULE_LICENSE("GPL");