Initial import

1 files changed, 1937 insertions, 0 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
new file mode 100644
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+++ b/include/net/sctp/structs.h
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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 Intel Corp.
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email addresses:
+ *    lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ *    Randall Stewart	    <randall@sctp.chicago.il.us>
+ *    Ken Morneau	    <kmorneau@cisco.com>
+ *    Qiaobing Xie	    <qxie1@email.mot.com>
+ *    La Monte H.P. Yarroll <piggy@acm.org>
+ *    Karl Knutson	    <karl@athena.chicago.il.us>
+ *    Jon Grimm		    <jgrimm@us.ibm.com>
+ *    Xingang Guo	    <xingang.guo@intel.com>
+ *    Hui Huang		    <hui.huang@nokia.com>
+ *    Sridhar Samudrala	    <sri@us.ibm.com>
+ *    Daisy Chang	    <daisyc@us.ibm.com>
+ *    Dajiang Zhang	    <dajiang.zhang@nokia.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>
+ */
+
+#ifndef __sctp_structs_h__
+#define __sctp_structs_h__
+
+#include <linux/ktime.h>
+#include <linux/socket.h>	/* linux/in.h needs this!!    */
+#include <linux/in.h>		/* We get struct sockaddr_in. */
+#include <linux/in6.h>		/* We get struct in6_addr     */
+#include <linux/ipv6.h>
+#include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
+#include <linux/atomic.h>		/* This gets us atomic counters.  */
+#include <linux/skbuff.h>	/* We need sk_buff_head. */
+#include <linux/workqueue.h>	/* We need tq_struct.	 */
+#include <linux/sctp.h>		/* We need sctp* header structs.  */
+#include <net/sctp/auth.h>	/* We need auth specific structs */
+
+/* A convenience structure for handling sockaddr structures.
+ * We should wean ourselves off this.
+ */
+union sctp_addr {
+	struct sockaddr_in v4;
+	struct sockaddr_in6 v6;
+	struct sockaddr sa;
+};
+
+/* Forward declarations for data structures. */
+struct sctp_globals;
+struct sctp_endpoint;
+struct sctp_association;
+struct sctp_transport;
+struct sctp_packet;
+struct sctp_chunk;
+struct sctp_inq;
+struct sctp_outq;
+struct sctp_bind_addr;
+struct sctp_ulpq;
+struct sctp_ep_common;
+struct sctp_ssnmap;
+struct crypto_hash;
+
+
+#include <net/sctp/tsnmap.h>
+#include <net/sctp/ulpevent.h>
+#include <net/sctp/ulpqueue.h>
+
+/* Structures useful for managing bind/connect. */
+
+struct sctp_bind_bucket {
+	unsigned short	port;
+	unsigned short	fastreuse;
+	struct hlist_node	node;
+	struct hlist_head	owner;
+	struct net	*net;
+};
+
+struct sctp_bind_hashbucket {
+	spinlock_t	lock;
+	struct hlist_head	chain;
+};
+
+/* Used for hashing all associations.  */
+struct sctp_hashbucket {
+	rwlock_t	lock;
+	struct hlist_head	chain;
+} __attribute__((__aligned__(8)));
+
+
+/* The SCTP globals structure. */
+extern struct sctp_globals {
+	/* This is a list of groups of functions for each address
+	 * family that we support.
+	 */
+	struct list_head address_families;
+
+	/* This is the hash of all endpoints. */
+	struct sctp_hashbucket *ep_hashtable;
+	/* This is the hash of all associations. */
+	struct sctp_hashbucket *assoc_hashtable;
+	/* This is the sctp port control hash.	*/
+	struct sctp_bind_hashbucket *port_hashtable;
+
+	/* Sizes of above hashtables. */
+	int ep_hashsize;
+	int assoc_hashsize;
+	int port_hashsize;
+
+	/* Default initialization values to be applied to new associations. */
+	__u16 max_instreams;
+	__u16 max_outstreams;
+
+	/* Flag to indicate whether computing and verifying checksum
+	 * is disabled. */
+        bool checksum_disable;
+} sctp_globals;
+
+#define sctp_max_instreams		(sctp_globals.max_instreams)
+#define sctp_max_outstreams		(sctp_globals.max_outstreams)
+#define sctp_address_families		(sctp_globals.address_families)
+#define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
+#define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
+#define sctp_assoc_hashsize		(sctp_globals.assoc_hashsize)
+#define sctp_assoc_hashtable		(sctp_globals.assoc_hashtable)
+#define sctp_port_hashsize		(sctp_globals.port_hashsize)
+#define sctp_port_hashtable		(sctp_globals.port_hashtable)
+#define sctp_checksum_disable		(sctp_globals.checksum_disable)
+
+/* SCTP Socket type: UDP or TCP style. */
+typedef enum {
+	SCTP_SOCKET_UDP = 0,
+	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
+	SCTP_SOCKET_TCP
+} sctp_socket_type_t;
+
+/* Per socket SCTP information. */
+struct sctp_sock {
+	/* inet_sock has to be the first member of sctp_sock */
+	struct inet_sock inet;
+	/* What kind of a socket is this? */
+	sctp_socket_type_t type;
+
+	/* PF_ family specific functions.  */
+	struct sctp_pf *pf;
+
+	/* Access to HMAC transform. */
+	struct crypto_hash *hmac;
+	char *sctp_hmac_alg;
+
+	/* What is our base endpointer? */
+	struct sctp_endpoint *ep;
+
+	struct sctp_bind_bucket *bind_hash;
+	/* Various Socket Options.  */
+	__u16 default_stream;
+	__u32 default_ppid;
+	__u16 default_flags;
+	__u32 default_context;
+	__u32 default_timetolive;
+	__u32 default_rcv_context;
+	int max_burst;
+
+	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
+	 * the destination address every heartbeat interval. This value
+	 * will be inherited by all new associations.
+	 */
+	__u32 hbinterval;
+
+	/* This is the max_retrans value for new associations. */
+	__u16 pathmaxrxt;
+
+	/* The initial Path MTU to use for new associations. */
+	__u32 pathmtu;
+
+	/* The default SACK delay timeout for new associations. */
+	__u32 sackdelay;
+	__u32 sackfreq;
+
+	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
+	__u32 param_flags;
+
+	struct sctp_initmsg initmsg;
+	struct sctp_rtoinfo rtoinfo;
+	struct sctp_paddrparams paddrparam;
+	struct sctp_event_subscribe subscribe;
+	struct sctp_assocparams assocparams;
+
+	int user_frag;
+
+	__u32 autoclose;
+	__u8 nodelay;
+	__u8 disable_fragments;
+	__u8 v4mapped;
+	__u8 frag_interleave;
+	__u32 adaptation_ind;
+	__u32 pd_point;
+	__u8 recvrcvinfo;
+	__u8 recvnxtinfo;
+
+	atomic_t pd_mode;
+	/* Receive to here while partial delivery is in effect. */
+	struct sk_buff_head pd_lobby;
+
+	/* These must be the last fields, as they will skipped on copies,
+	 * like on accept and peeloff operations
+	 */
+	struct list_head auto_asconf_list;
+	int do_auto_asconf;
+};
+
+static inline struct sctp_sock *sctp_sk(const struct sock *sk)
+{
+       return (struct sctp_sock *)sk;
+}
+
+static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
+{
+       return (struct sock *)sp;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+struct sctp6_sock {
+       struct sctp_sock  sctp;
+       struct ipv6_pinfo inet6;
+};
+#endif /* CONFIG_IPV6 */
+
+
+/* This is our APPLICATION-SPECIFIC state cookie.
+ * THIS IS NOT DICTATED BY THE SPECIFICATION.
+ */
+/* These are the parts of an association which we send in the cookie.
+ * Most of these are straight out of:
+ * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
+ *
+ */
+
+struct sctp_cookie {
+
+	/* My	       : Tag expected in every inbound packet and sent
+	 * Verification: in the INIT or INIT ACK chunk.
+	 * Tag	       :
+	 */
+	__u32 my_vtag;
+
+	/* Peer's      : Tag expected in every outbound packet except
+	 * Verification: in the INIT chunk.
+	 * Tag	       :
+	 */
+	__u32 peer_vtag;
+
+	/* The rest of these are not from the spec, but really need to
+	 * be in the cookie.
+	 */
+
+	/* My Tie Tag  : Assist in discovering a restarting association. */
+	__u32 my_ttag;
+
+	/* Peer's Tie Tag: Assist in discovering a restarting association. */
+	__u32 peer_ttag;
+
+	/* When does this cookie expire? */
+	ktime_t expiration;
+
+	/* Number of inbound/outbound streams which are set
+	 * and negotiated during the INIT process.
+	 */
+	__u16 sinit_num_ostreams;
+	__u16 sinit_max_instreams;
+
+	/* This is the first sequence number I used.  */
+	__u32 initial_tsn;
+
+	/* This holds the originating address of the INIT packet.  */
+	union sctp_addr peer_addr;
+
+	/* IG Section 2.35.3 
+	 * Include the source port of the INIT-ACK
+	 */
+	__u16		my_port;
+
+	__u8 prsctp_capable;
+
+	/* Padding for future use */
+	__u8 padding;  		
+
+	__u32 adaptation_ind;
+
+	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
+	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS * sizeof(__u16) + 2];
+	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
+
+	/* This is a shim for my peer's INIT packet, followed by
+	 * a copy of the raw address list of the association.
+	 * The length of the raw address list is saved in the
+	 * raw_addr_list_len field, which will be used at the time when
+	 * the association TCB is re-constructed from the cookie.
+	 */
+	__u32 raw_addr_list_len;
+	struct sctp_init_chunk peer_init[0];
+};
+
+
+/* The format of our cookie that we send to our peer. */
+struct sctp_signed_cookie {
+	__u8 signature[SCTP_SECRET_SIZE];
+	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
+	struct sctp_cookie c;
+} __packed;
+
+/* This is another convenience type to allocate memory for address
+ * params for the maximum size and pass such structures around
+ * internally.
+ */
+union sctp_addr_param {
+	struct sctp_paramhdr p;
+	struct sctp_ipv4addr_param v4;
+	struct sctp_ipv6addr_param v6;
+};
+
+/* A convenience type to allow walking through the various
+ * parameters and avoid casting all over the place.
+ */
+union sctp_params {
+	void *v;
+	struct sctp_paramhdr *p;
+	struct sctp_cookie_preserve_param *life;
+	struct sctp_hostname_param *dns;
+	struct sctp_cookie_param *cookie;
+	struct sctp_supported_addrs_param *sat;
+	struct sctp_ipv4addr_param *v4;
+	struct sctp_ipv6addr_param *v6;
+	union sctp_addr_param *addr;
+	struct sctp_adaptation_ind_param *aind;
+	struct sctp_supported_ext_param *ext;
+	struct sctp_random_param *random;
+	struct sctp_chunks_param *chunks;
+	struct sctp_hmac_algo_param *hmac_algo;
+	struct sctp_addip_param *addip;
+};
+
+/* RFC 2960.  Section 3.3.5 Heartbeat.
+ *    Heartbeat Information: variable length
+ *    The Sender-specific Heartbeat Info field should normally include
+ *    information about the sender's current time when this HEARTBEAT
+ *    chunk is sent and the destination transport address to which this
+ *    HEARTBEAT is sent (see Section 8.3).
+ */
+typedef struct sctp_sender_hb_info {
+	struct sctp_paramhdr param_hdr;
+	union sctp_addr daddr;
+	unsigned long sent_at;
+	__u64 hb_nonce;
+} __packed sctp_sender_hb_info_t;
+
+/*
+ *  RFC 2960 1.3.2 Sequenced Delivery within Streams
+ *
+ *  The term "stream" is used in SCTP to refer to a sequence of user
+ *  messages that are to be delivered to the upper-layer protocol in
+ *  order with respect to other messages within the same stream.  This is
+ *  in contrast to its usage in TCP, where it refers to a sequence of
+ *  bytes (in this document a byte is assumed to be eight bits).
+ *  ...
+ *
+ *  This is the structure we use to track both our outbound and inbound
+ *  SSN, or Stream Sequence Numbers.
+ */
+
+struct sctp_stream {
+	__u16 *ssn;
+	unsigned int len;
+};
+
+struct sctp_ssnmap {
+	struct sctp_stream in;
+	struct sctp_stream out;
+};
+
+struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
+				    gfp_t gfp);
+void sctp_ssnmap_free(struct sctp_ssnmap *map);
+void sctp_ssnmap_clear(struct sctp_ssnmap *map);
+
+/* What is the current SSN number for this stream? */
+static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
+{
+	return stream->ssn[id];
+}
+
+/* Return the next SSN number for this stream.	*/
+static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
+{
+	return stream->ssn[id]++;
+}
+
+/* Skip over this ssn and all below. */
+static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id, 
+				 __u16 ssn)
+{
+	stream->ssn[id] = ssn+1;
+}
+              
+/*
+ * Pointers to address related SCTP functions.
+ * (i.e. things that depend on the address family.)
+ */
+struct sctp_af {
+	int		(*sctp_xmit)	(struct sk_buff *skb,
+					 struct sctp_transport *);
+	int		(*setsockopt)	(struct sock *sk,
+					 int level,
+					 int optname,
+					 char __user *optval,
+					 unsigned int optlen);
+	int		(*getsockopt)	(struct sock *sk,
+					 int level,
+					 int optname,
+					 char __user *optval,
+					 int __user *optlen);
+	int		(*compat_setsockopt)	(struct sock *sk,
+					 int level,
+					 int optname,
+					 char __user *optval,
+					 unsigned int optlen);
+	int		(*compat_getsockopt)	(struct sock *sk,
+					 int level,
+					 int optname,
+					 char __user *optval,
+					 int __user *optlen);
+	void		(*get_dst)	(struct sctp_transport *t,
+					 union sctp_addr *saddr,
+					 struct flowi *fl,
+					 struct sock *sk);
+	void		(*get_saddr)	(struct sctp_sock *sk,
+					 struct sctp_transport *t,
+					 struct flowi *fl);
+	void		(*copy_addrlist) (struct list_head *,
+					  struct net_device *);
+	int		(*cmp_addr)	(const union sctp_addr *addr1,
+					 const union sctp_addr *addr2);
+	void		(*addr_copy)	(union sctp_addr *dst,
+					 union sctp_addr *src);
+	void		(*from_skb)	(union sctp_addr *,
+					 struct sk_buff *skb,
+					 int saddr);
+	void		(*from_sk)	(union sctp_addr *,
+					 struct sock *sk);
+	void		(*from_addr_param) (union sctp_addr *,
+					    union sctp_addr_param *,
+					    __be16 port, int iif);
+	int		(*to_addr_param) (const union sctp_addr *,
+					  union sctp_addr_param *); 
+	int		(*addr_valid)	(union sctp_addr *,
+					 struct sctp_sock *,
+					 const struct sk_buff *);
+	sctp_scope_t	(*scope) (union sctp_addr *);
+	void		(*inaddr_any)	(union sctp_addr *, __be16);
+	int		(*is_any)	(const union sctp_addr *);
+	int		(*available)	(union sctp_addr *,
+					 struct sctp_sock *);
+	int		(*skb_iif)	(const struct sk_buff *sk);
+	int		(*is_ce)	(const struct sk_buff *sk);
+	void		(*seq_dump_addr)(struct seq_file *seq,
+					 union sctp_addr *addr);
+	void		(*ecn_capable)(struct sock *sk);
+	__u16		net_header_len;
+	int		sockaddr_len;
+	sa_family_t	sa_family;
+	struct list_head list;
+};
+
+struct sctp_af *sctp_get_af_specific(sa_family_t);
+int sctp_register_af(struct sctp_af *);
+
+/* Protocol family functions. */
+struct sctp_pf {
+	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
+	void (*skb_msgname)  (struct sk_buff *, char *, int *);
+	int  (*af_supported) (sa_family_t, struct sctp_sock *);
+	int  (*cmp_addr) (const union sctp_addr *,
+			  const union sctp_addr *,
+			  struct sctp_sock *);
+	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
+	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
+	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
+	struct sock *(*create_accept_sk) (struct sock *sk,
+					  struct sctp_association *asoc);
+	int (*addr_to_user)(struct sctp_sock *sk, union sctp_addr *addr);
+	void (*to_sk_saddr)(union sctp_addr *, struct sock *sk);
+	void (*to_sk_daddr)(union sctp_addr *, struct sock *sk);
+	struct sctp_af *af;
+};
+
+
+/* Structure to track chunk fragments that have been acked, but peer
+ * fragments of the same message have not.
+ */
+struct sctp_datamsg {
+	/* Chunks waiting to be submitted to lower layer. */
+	struct list_head chunks;
+	/* Reference counting. */
+	atomic_t refcnt;
+	/* When is this message no longer interesting to the peer? */
+	unsigned long expires_at;
+	/* Did the messenge fail to send? */
+	int send_error;
+	u8 send_failed:1,
+	   can_abandon:1,   /* can chunks from this message can be abandoned. */
+	   can_delay;	    /* should this message be Nagle delayed */
+};
+
+struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
+					    struct sctp_sndrcvinfo *,
+					    struct iov_iter *);
+void sctp_datamsg_free(struct sctp_datamsg *);
+void sctp_datamsg_put(struct sctp_datamsg *);
+void sctp_chunk_fail(struct sctp_chunk *, int error);
+int sctp_chunk_abandoned(struct sctp_chunk *);
+
+/* RFC2960 1.4 Key Terms
+ *
+ * o Chunk: A unit of information within an SCTP packet, consisting of
+ * a chunk header and chunk-specific content.
+ *
+ * As a matter of convenience, we remember the SCTP common header for
+ * each chunk as well as a few other header pointers...
+ */
+struct sctp_chunk {
+	struct list_head list;
+
+	atomic_t refcnt;
+
+	/* This is our link to the per-transport transmitted list.  */
+	struct list_head transmitted_list;
+
+	/* This field is used by chunks that hold fragmented data.
+	 * For the first fragment this is the list that holds the rest of
+	 * fragments. For the remaining fragments, this is the link to the
+	 * frag_list maintained in the first fragment.
+	 */
+	struct list_head frag_list;
+
+	/* This points to the sk_buff containing the actual data.  */
+	struct sk_buff *skb;
+
+	/* These are the SCTP headers by reverse order in a packet.
+	 * Note that some of these may happen more than once.  In that
+	 * case, we point at the "current" one, whatever that means
+	 * for that level of header.
+	 */
+
+	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
+	union sctp_params param_hdr;
+	union {
+		__u8 *v;
+		struct sctp_datahdr *data_hdr;
+		struct sctp_inithdr *init_hdr;
+		struct sctp_sackhdr *sack_hdr;
+		struct sctp_heartbeathdr *hb_hdr;
+		struct sctp_sender_hb_info *hbs_hdr;
+		struct sctp_shutdownhdr *shutdown_hdr;
+		struct sctp_signed_cookie *cookie_hdr;
+		struct sctp_ecnehdr *ecne_hdr;
+		struct sctp_cwrhdr *ecn_cwr_hdr;
+		struct sctp_errhdr *err_hdr;
+		struct sctp_addiphdr *addip_hdr;
+		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
+		struct sctp_authhdr *auth_hdr;
+	} subh;
+
+	__u8 *chunk_end;
+
+	struct sctp_chunkhdr *chunk_hdr;
+	struct sctphdr *sctp_hdr;
+
+	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
+	struct sctp_sndrcvinfo sinfo;
+
+	/* Which association does this belong to?  */
+	struct sctp_association *asoc;
+
+	/* What endpoint received this chunk? */
+	struct sctp_ep_common *rcvr;
+
+	/* We fill this in if we are calculating RTT. */
+	unsigned long sent_at;
+
+	/* What is the origin IP address for this chunk?  */
+	union sctp_addr source;
+	/* Destination address for this chunk. */
+	union sctp_addr dest;
+
+	/* For outbound message, track all fragments for SEND_FAILED. */
+	struct sctp_datamsg *msg;
+
+	/* For an inbound chunk, this tells us where it came from.
+	 * For an outbound chunk, it tells us where we'd like it to
+	 * go.	It is NULL if we have no preference.
+	 */
+	struct sctp_transport *transport;
+
+	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
+	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
+	 * spec violates the principle premis that all chunks are processed
+	 * in order.
+	 */
+	struct sk_buff *auth_chunk;
+
+#define SCTP_CAN_FRTX 0x0
+#define SCTP_NEED_FRTX 0x1
+#define SCTP_DONT_FRTX 0x2
+	__u16	rtt_in_progress:1,	/* This chunk used for RTT calc? */
+		resent:1,		/* Has this chunk ever been resent. */
+		has_tsn:1,		/* Does this chunk have a TSN yet? */
+		has_ssn:1,		/* Does this chunk have a SSN yet? */
+		singleton:1,		/* Only chunk in the packet? */
+		end_of_packet:1,	/* Last chunk in the packet? */
+		ecn_ce_done:1,		/* Have we processed the ECN CE bit? */
+		pdiscard:1,		/* Discard the whole packet now? */
+		tsn_gap_acked:1,	/* Is this chunk acked by a GAP ACK? */
+		data_accepted:1,	/* At least 1 chunk accepted */
+		auth:1,			/* IN: was auth'ed | OUT: needs auth */
+		has_asconf:1,		/* IN: have seen an asconf before */
+		tsn_missing_report:2,	/* Data chunk missing counter. */
+		fast_retransmit:2;	/* Is this chunk fast retransmitted? */
+};
+
+void sctp_chunk_hold(struct sctp_chunk *);
+void sctp_chunk_put(struct sctp_chunk *);
+int sctp_user_addto_chunk(struct sctp_chunk *chunk, int len,
+			  struct iov_iter *from);
+void sctp_chunk_free(struct sctp_chunk *);
+void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
+struct sctp_chunk *sctp_chunkify(struct sk_buff *,
+				 const struct sctp_association *,
+				 struct sock *);
+void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
+		     union sctp_addr *);
+const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
+
+enum {
+	SCTP_ADDR_NEW,		/* new address added to assoc/ep */
+	SCTP_ADDR_SRC,		/* address can be used as source */
+	SCTP_ADDR_DEL,		/* address about to be deleted */
+};
+
+/* This is a structure for holding either an IPv6 or an IPv4 address.  */
+struct sctp_sockaddr_entry {
+	struct list_head list;
+	struct rcu_head	rcu;
+	union sctp_addr a;
+	__u8 state;
+	__u8 valid;
+};
+
+#define SCTP_ADDRESS_TICK_DELAY	500
+
+typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
+
+/* This structure holds lists of chunks as we are assembling for
+ * transmission.
+ */
+struct sctp_packet {
+	/* These are the SCTP header values (host order) for the packet. */
+	__u16 source_port;
+	__u16 destination_port;
+	__u32 vtag;
+
+	/* This contains the payload chunks.  */
+	struct list_head chunk_list;
+
+	/* This is the overhead of the sctp and ip headers. */
+	size_t overhead;
+	/* This is the total size of all chunks INCLUDING padding.  */
+	size_t size;
+
+	/* The packet is destined for this transport address.
+	 * The function we finally use to pass down to the next lower
+	 * layer lives in the transport structure.
+	 */
+	struct sctp_transport *transport;
+
+	/* pointer to the auth chunk for this packet */
+	struct sctp_chunk *auth;
+
+	u8  has_cookie_echo:1,	/* This packet contains a COOKIE-ECHO chunk. */
+	    has_sack:1,		/* This packet contains a SACK chunk. */
+	    has_auth:1,		/* This packet contains an AUTH chunk */
+	    has_data:1,		/* This packet contains at least 1 DATA chunk */
+	    ipfragok:1;		/* So let ip fragment this packet */
+};
+
+struct sctp_packet *sctp_packet_init(struct sctp_packet *,
+				     struct sctp_transport *,
+				     __u16 sport, __u16 dport);
+struct sctp_packet *sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
+sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
+                                       struct sctp_chunk *, int);
+sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
+                                     struct sctp_chunk *);
+int sctp_packet_transmit(struct sctp_packet *);
+void sctp_packet_free(struct sctp_packet *);
+
+static inline int sctp_packet_empty(struct sctp_packet *packet)
+{
+	return packet->size == packet->overhead;
+}
+
+/* This represents a remote transport address.
+ * For local transport addresses, we just use union sctp_addr.
+ *
+ * RFC2960 Section 1.4 Key Terms
+ *
+ *   o	Transport address:  A Transport Address is traditionally defined
+ *	by Network Layer address, Transport Layer protocol and Transport
+ *	Layer port number.  In the case of SCTP running over IP, a
+ *	transport address is defined by the combination of an IP address
+ *	and an SCTP port number (where SCTP is the Transport protocol).
+ *
+ * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
+ *
+ *   o	The sender keeps a separate congestion control parameter set for
+ *	each of the destination addresses it can send to (not each
+ *	source-destination pair but for each destination).  The parameters
+ *	should decay if the address is not used for a long enough time
+ *	period.
+ *
+ */
+struct sctp_transport {
+	/* A list of transports. */
+	struct list_head transports;
+
+	/* Reference counting. */
+	atomic_t refcnt;
+	__u32	 dead:1,
+		/* RTO-Pending : A flag used to track if one of the DATA
+		 *		chunks sent to this address is currently being
+		 *		used to compute a RTT. If this flag is 0,
+		 *		the next DATA chunk sent to this destination
+		 *		should be used to compute a RTT and this flag
+		 *		should be set. Every time the RTT
+		 *		calculation completes (i.e. the DATA chunk
+		 *		is SACK'd) clear this flag.
+		 */
+		 rto_pending:1,
+
+		/*
+		 * hb_sent : a flag that signals that we have a pending
+		 * heartbeat.
+		 */
+		hb_sent:1,
+
+		/* Is the Path MTU update pending on this tranport */
+		pmtu_pending:1;
+
+	/* Has this transport moved the ctsn since we last sacked */
+	__u32 sack_generation;
+	u32 dst_cookie;
+
+	struct flowi fl;
+
+	/* This is the peer's IP address and port. */
+	union sctp_addr ipaddr;
+
+	/* These are the functions we call to handle LLP stuff.	 */
+	struct sctp_af *af_specific;
+
+	/* Which association do we belong to?  */
+	struct sctp_association *asoc;
+
+	/* RFC2960
+	 *
+	 * 12.3 Per Transport Address Data
+	 *
+	 * For each destination transport address in the peer's
+	 * address list derived from the INIT or INIT ACK chunk, a
+	 * number of data elements needs to be maintained including:
+	 */
+	/* RTO	       : The current retransmission timeout value.  */
+	unsigned long rto;
+
+	__u32 rtt;		/* This is the most recent RTT.	 */
+
+	/* RTTVAR      : The current RTT variation.  */
+	__u32 rttvar;
+
+	/* SRTT	       : The current smoothed round trip time.	*/
+	__u32 srtt;
+
+	/*
+	 * These are the congestion stats.
+	 */
+	/* cwnd	       : The current congestion window.	 */
+	__u32 cwnd;		  /* This is the actual cwnd.  */
+
+	/* ssthresh    : The current slow start threshold value.  */
+	__u32 ssthresh;
+
+	/* partial     : The tracking method for increase of cwnd when in
+	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
+	 */
+	__u32 partial_bytes_acked;
+
+	/* Data that has been sent, but not acknowledged. */
+	__u32 flight_size;
+
+	__u32 burst_limited;	/* Holds old cwnd when max.burst is applied */
+
+	/* Destination */
+	struct dst_entry *dst;
+	/* Source address. */
+	union sctp_addr saddr;
+
+	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
+	 * the destination address every heartbeat interval.
+	 */
+	unsigned long hbinterval;
+
+	/* SACK delay timeout */
+	unsigned long sackdelay;
+	__u32 sackfreq;
+
+	/* When was the last time that we heard from this transport? We use
+	 * this to pick new active and retran paths.
+	 */
+	ktime_t last_time_heard;
+
+	/* Last time(in jiffies) when cwnd is reduced due to the congestion
+	 * indication based on ECNE chunk.
+	 */
+	unsigned long last_time_ecne_reduced;
+
+	/* This is the max_retrans value for the transport and will
+	 * be initialized from the assocs value.  This can be changed
+	 * using the SCTP_SET_PEER_ADDR_PARAMS socket option.
+	 */
+	__u16 pathmaxrxt;
+
+	/* This is the partially failed retrans value for the transport
+	 * and will be initialized from the assocs value.  This can be changed
+	 * using the SCTP_PEER_ADDR_THLDS socket option
+	 */
+	int pf_retrans;
+	/* PMTU	      : The current known path MTU.  */
+	__u32 pathmtu;
+
+	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
+	__u32 param_flags;
+
+	/* The number of times INIT has been sent on this transport. */
+	int init_sent_count;
+
+	/* state       : The current state of this destination,
+	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKNOWN.
+	 */
+	int state;
+
+	/* These are the error stats for this destination.  */
+
+	/* Error count : The current error count for this destination.	*/
+	unsigned short error_count;
+
+	/* Per	       : A timer used by each destination.
+	 * Destination :
+	 * Timer       :
+	 *
+	 * [Everywhere else in the text this is called T3-rtx. -ed]
+	 */
+	struct timer_list T3_rtx_timer;
+
+	/* Heartbeat timer is per destination. */
+	struct timer_list hb_timer;
+
+	/* Timer to handle ICMP proto unreachable envets */
+	struct timer_list proto_unreach_timer;
+
+	/* Since we're using per-destination retransmission timers
+	 * (see above), we're also using per-destination "transmitted"
+	 * queues.  This probably ought to be a private struct
+	 * accessible only within the outqueue, but it's not, yet.
+	 */
+	struct list_head transmitted;
+
+	/* We build bundle-able packets for this transport here.  */
+	struct sctp_packet packet;
+
+	/* This is the list of transports that have chunks to send.  */
+	struct list_head send_ready;
+
+	/* State information saved for SFR_CACC algorithm. The key
+	 * idea in SFR_CACC is to maintain state at the sender on a
+	 * per-destination basis when a changeover happens.
+	 *	char changeover_active;
+	 *	char cycling_changeover;
+	 *	__u32 next_tsn_at_change;
+	 *	char cacc_saw_newack;
+	 */
+	struct {
+		/* An unsigned integer, which stores the next TSN to be
+		 * used by the sender, at the moment of changeover.
+		 */
+		__u32 next_tsn_at_change;
+
+		/* A flag which indicates the occurrence of a changeover */
+		char changeover_active;
+
+		/* A flag which indicates whether the change of primary is
+		 * the first switch to this destination address during an
+		 * active switch.
+		 */
+		char cycling_changeover;
+
+		/* A temporary flag, which is used during the processing of
+		 * a SACK to estimate the causative TSN(s)'s group.
+		 */
+		char cacc_saw_newack;
+	} cacc;
+
+	/* 64-bit random number sent with heartbeat. */
+	__u64 hb_nonce;
+
+	struct rcu_head rcu;
+};
+
+struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,
+					  gfp_t);
+void sctp_transport_set_owner(struct sctp_transport *,
+			      struct sctp_association *);
+void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
+			  struct sctp_sock *);
+void sctp_transport_pmtu(struct sctp_transport *, struct sock *sk);
+void sctp_transport_free(struct sctp_transport *);
+void sctp_transport_reset_timers(struct sctp_transport *);
+void sctp_transport_hold(struct sctp_transport *);
+void sctp_transport_put(struct sctp_transport *);
+void sctp_transport_update_rto(struct sctp_transport *, __u32);
+void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
+void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
+void sctp_transport_burst_limited(struct sctp_transport *);
+void sctp_transport_burst_reset(struct sctp_transport *);
+unsigned long sctp_transport_timeout(struct sctp_transport *);
+void sctp_transport_reset(struct sctp_transport *);
+void sctp_transport_update_pmtu(struct sock *, struct sctp_transport *, u32);
+void sctp_transport_immediate_rtx(struct sctp_transport *);
+
+
+/* This is the structure we use to queue packets as they come into
+ * SCTP.  We write packets to it and read chunks from it.
+ */
+struct sctp_inq {
+	/* This is actually a queue of sctp_chunk each
+	 * containing a partially decoded packet.
+	 */
+	struct list_head in_chunk_list;
+	/* This is the packet which is currently off the in queue and is
+	 * being worked on through the inbound chunk processing.
+	 */
+	struct sctp_chunk *in_progress;
+
+	/* This is the delayed task to finish delivering inbound
+	 * messages.
+	 */
+	struct work_struct immediate;
+};
+
+void sctp_inq_init(struct sctp_inq *);
+void sctp_inq_free(struct sctp_inq *);
+void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
+struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
+struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
+void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
+
+/* This is the structure we use to hold outbound chunks.  You push
+ * chunks in and they automatically pop out the other end as bundled
+ * packets (it calls (*output_handler)()).
+ *
+ * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
+ * and 8.2 of the v13 draft.
+ *
+ * It handles retransmissions.	The connection to the timeout portion
+ * of the state machine is through sctp_..._timeout() and timeout_handler.
+ *
+ * If you feed it SACKs, it will eat them.
+ *
+ * If you give it big chunks, it will fragment them.
+ *
+ * It assigns TSN's to data chunks.  This happens at the last possible
+ * instant before transmission.
+ *
+ * When free()'d, it empties itself out via output_handler().
+ */
+struct sctp_outq {
+	struct sctp_association *asoc;
+
+	/* Data pending that has never been transmitted.  */
+	struct list_head out_chunk_list;
+
+	unsigned int out_qlen;	/* Total length of queued data chunks. */
+
+	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
+	unsigned int error;
+
+	/* These are control chunks we want to send.  */
+	struct list_head control_chunk_list;
+
+	/* These are chunks that have been sacked but are above the
+	 * CTSN, or cumulative tsn ack point.
+	 */
+	struct list_head sacked;
+
+	/* Put chunks on this list to schedule them for
+	 * retransmission.
+	 */
+	struct list_head retransmit;
+
+	/* Put chunks on this list to save them for FWD TSN processing as
+	 * they were abandoned.
+	 */
+	struct list_head abandoned;
+
+	/* How many unackd bytes do we have in-flight?	*/
+	__u32 outstanding_bytes;
+
+	/* Are we doing fast-rtx on this queue */
+	char fast_rtx;
+
+	/* Corked? */
+	char cork;
+};
+
+void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
+void sctp_outq_teardown(struct sctp_outq *);
+void sctp_outq_free(struct sctp_outq*);
+int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk);
+int sctp_outq_sack(struct sctp_outq *, struct sctp_chunk *);
+int sctp_outq_is_empty(const struct sctp_outq *);
+void sctp_outq_restart(struct sctp_outq *);
+
+void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
+		     sctp_retransmit_reason_t);
+void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
+int sctp_outq_uncork(struct sctp_outq *);
+/* Uncork and flush an outqueue.  */
+static inline void sctp_outq_cork(struct sctp_outq *q)
+{
+	q->cork = 1;
+}
+
+/* These bind address data fields common between endpoints and associations */
+struct sctp_bind_addr {
+
+	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
+	 *
+	 * SCTP Port:	The local SCTP port number the endpoint is
+	 *		bound to.
+	 */
+	__u16 port;
+
+	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
+	 *
+	 * Address List: The list of IP addresses that this instance
+	 *	has bound.  This information is passed to one's
+	 *	peer(s) in INIT and INIT ACK chunks.
+	 */
+	struct list_head address_list;
+};
+
+void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
+void sctp_bind_addr_free(struct sctp_bind_addr *);
+int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
+			const struct sctp_bind_addr *src,
+			sctp_scope_t scope, gfp_t gfp,
+			int flags);
+int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
+			const struct sctp_bind_addr *src,
+			gfp_t gfp);
+int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
+		       __u8 addr_state, gfp_t gfp);
+int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *);
+int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
+			 struct sctp_sock *);
+int sctp_bind_addr_conflict(struct sctp_bind_addr *, const union sctp_addr *,
+			 struct sctp_sock *, struct sctp_sock *);
+int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
+			 const union sctp_addr *addr);
+union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
+					const union sctp_addr	*addrs,
+					int			addrcnt,
+					struct sctp_sock	*opt);
+union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
+					 int *addrs_len,
+					 gfp_t gfp);
+int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
+			   __u16 port, gfp_t gfp);
+
+sctp_scope_t sctp_scope(const union sctp_addr *);
+int sctp_in_scope(struct net *net, const union sctp_addr *addr, const sctp_scope_t scope);
+int sctp_is_any(struct sock *sk, const union sctp_addr *addr);
+int sctp_is_ep_boundall(struct sock *sk);
+
+
+/* What type of endpoint?  */
+typedef enum {
+	SCTP_EP_TYPE_SOCKET,
+	SCTP_EP_TYPE_ASSOCIATION,
+} sctp_endpoint_type_t;
+
+/*
+ * A common base class to bridge the implmentation view of a
+ * socket (usually listening) endpoint versus an association's
+ * local endpoint.
+ * This common structure is useful for several purposes:
+ *   1) Common interface for lookup routines.
+ *	a) Subfunctions work for either endpoint or association
+ *	b) Single interface to lookup allows hiding the lookup lock rather
+ *	   than acquiring it externally.
+ *   2) Common interface for the inbound chunk handling/state machine.
+ *   3) Common object handling routines for reference counting, etc.
+ *   4) Disentangle association lookup from endpoint lookup, where we
+ *	do not have to find our endpoint to find our association.
+ *
+ */
+
+struct sctp_ep_common {
+	/* Fields to help us manage our entries in the hash tables. */
+	struct hlist_node node;
+	int hashent;
+
+	/* Runtime type information.  What kind of endpoint is this? */
+	sctp_endpoint_type_t type;
+
+	/* Some fields to help us manage this object.
+	 *   refcnt   - Reference count access to this object.
+	 *   dead     - Do not attempt to use this object.
+	 */
+	atomic_t    refcnt;
+	bool	    dead;
+
+	/* What socket does this endpoint belong to?  */
+	struct sock *sk;
+
+	/* This is where we receive inbound chunks.  */
+	struct sctp_inq	  inqueue;
+
+	/* This substructure includes the defining parameters of the
+	 * endpoint:
+	 * bind_addr.port is our shared port number.
+	 * bind_addr.address_list is our set of local IP addresses.
+	 */
+	struct sctp_bind_addr bind_addr;
+};
+
+
+/* RFC Section 1.4 Key Terms
+ *
+ * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
+ *   multi-homed host, an SCTP endpoint is represented to its peers as a
+ *   combination of a set of eligible destination transport addresses to
+ *   which SCTP packets can be sent and a set of eligible source
+ *   transport addresses from which SCTP packets can be received.
+ *   All transport addresses used by an SCTP endpoint must use the
+ *   same port number, but can use multiple IP addresses. A transport
+ *   address used by an SCTP endpoint must not be used by another
+ *   SCTP endpoint. In other words, a transport address is unique
+ *   to an SCTP endpoint.
+ *
+ * From an implementation perspective, each socket has one of these.
+ * A TCP-style socket will have exactly one association on one of
+ * these.  An UDP-style socket will have multiple associations hanging
+ * off one of these.
+ */
+
+struct sctp_endpoint {
+	/* Common substructure for endpoint and association. */
+	struct sctp_ep_common base;
+
+	/* Associations: A list of current associations and mappings
+	 *	      to the data consumers for each association. This
+	 *	      may be in the form of a hash table or other
+	 *	      implementation dependent structure. The data
+	 *	      consumers may be process identification
+	 *	      information such as file descriptors, named pipe
+	 *	      pointer, or table pointers dependent on how SCTP
+	 *	      is implemented.
+	 */
+	/* This is really a list of struct sctp_association entries. */
+	struct list_head asocs;
+
+	/* Secret Key: A secret key used by this endpoint to compute
+	 *	      the MAC.	This SHOULD be a cryptographic quality
+	 *	      random number with a sufficient length.
+	 *	      Discussion in [RFC1750] can be helpful in
+	 *	      selection of the key.
+	 */
+	__u8 secret_key[SCTP_SECRET_SIZE];
+
+ 	/* digest:  This is a digest of the sctp cookie.  This field is
+ 	 * 	    only used on the receive path when we try to validate
+ 	 * 	    that the cookie has not been tampered with.  We put
+ 	 * 	    this here so we pre-allocate this once and can re-use
+ 	 * 	    on every receive.
+ 	 */
+ 	__u8 *digest;
+ 
+	/* sendbuf acct. policy.	*/
+	__u32 sndbuf_policy;
+
+	/* rcvbuf acct. policy.	*/
+	__u32 rcvbuf_policy;
+
+	/* SCTP AUTH: array of the HMACs that will be allocated
+	 * we need this per association so that we don't serialize
+	 */
+	struct crypto_hash **auth_hmacs;
+
+	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
+	 struct sctp_hmac_algo_param *auth_hmacs_list;
+
+	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
+	struct sctp_chunks_param *auth_chunk_list;
+
+	/* SCTP-AUTH: endpoint shared keys */
+	struct list_head endpoint_shared_keys;
+	__u16 active_key_id;
+	__u8  auth_enable;
+};
+
+/* Recover the outter endpoint structure. */
+static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
+{
+	struct sctp_endpoint *ep;
+
+	ep = container_of(base, struct sctp_endpoint, base);
+	return ep;
+}
+
+/* These are function signatures for manipulating endpoints.  */
+struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
+void sctp_endpoint_free(struct sctp_endpoint *);
+void sctp_endpoint_put(struct sctp_endpoint *);
+void sctp_endpoint_hold(struct sctp_endpoint *);
+void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
+struct sctp_association *sctp_endpoint_lookup_assoc(
+	const struct sctp_endpoint *ep,
+	const union sctp_addr *paddr,
+	struct sctp_transport **);
+int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
+				const union sctp_addr *);
+struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
+					struct net *, const union sctp_addr *);
+int sctp_has_association(struct net *net, const union sctp_addr *laddr,
+			 const union sctp_addr *paddr);
+
+int sctp_verify_init(struct net *net, const struct sctp_endpoint *ep,
+		     const struct sctp_association *asoc,
+		     sctp_cid_t, sctp_init_chunk_t *peer_init,
+		     struct sctp_chunk *chunk, struct sctp_chunk **err_chunk);
+int sctp_process_init(struct sctp_association *, struct sctp_chunk *chunk,
+		      const union sctp_addr *peer,
+		      sctp_init_chunk_t *init, gfp_t gfp);
+__u32 sctp_generate_tag(const struct sctp_endpoint *);
+__u32 sctp_generate_tsn(const struct sctp_endpoint *);
+
+struct sctp_inithdr_host {
+	__u32 init_tag;
+	__u32 a_rwnd;
+	__u16 num_outbound_streams;
+	__u16 num_inbound_streams;
+	__u32 initial_tsn;
+};
+
+/* SCTP_GET_ASSOC_STATS counters */
+struct sctp_priv_assoc_stats {
+	/* Maximum observed rto in the association during subsequent
+	 * observations. Value is set to 0 if no RTO measurement took place
+	 * The transport where the max_rto was observed is returned in
+	 * obs_rto_ipaddr
+	 */
+	struct sockaddr_storage obs_rto_ipaddr;
+	__u64 max_obs_rto;
+	/* Total In and Out SACKs received and sent */
+	__u64 isacks;
+	__u64 osacks;
+	/* Total In and Out packets received and sent */
+	__u64 opackets;
+	__u64 ipackets;
+	/* Total retransmitted chunks */
+	__u64 rtxchunks;
+	/* TSN received > next expected */
+	__u64 outofseqtsns;
+	/* Duplicate Chunks received */
+	__u64 idupchunks;
+	/* Gap Ack Blocks received */
+	__u64 gapcnt;
+	/* Unordered data chunks sent and received */
+	__u64 ouodchunks;
+	__u64 iuodchunks;
+	/* Ordered data chunks sent and received */
+	__u64 oodchunks;
+	__u64 iodchunks;
+	/* Control chunks sent and received */
+	__u64 octrlchunks;
+	__u64 ictrlchunks;
+};
+
+/* RFC2960
+ *
+ * 12. Recommended Transmission Control Block (TCB) Parameters
+ *
+ * This section details a recommended set of parameters that should
+ * be contained within the TCB for an implementation. This section is
+ * for illustrative purposes and should not be deemed as requirements
+ * on an implementation or as an exhaustive list of all parameters
+ * inside an SCTP TCB. Each implementation may need its own additional
+ * parameters for optimization.
+ */
+
+
+/* Here we have information about each individual association. */
+struct sctp_association {
+
+	/* A base structure common to endpoint and association.
+	 * In this context, it represents the associations's view
+	 * of the local endpoint of the association.
+	 */
+	struct sctp_ep_common base;
+
+	/* Associations on the same socket. */
+	struct list_head asocs;
+
+	/* association id. */
+	sctp_assoc_t assoc_id;
+
+	/* This is our parent endpoint.	 */
+	struct sctp_endpoint *ep;
+
+	/* These are those association elements needed in the cookie.  */
+	struct sctp_cookie c;
+
+	/* This is all information about our peer.  */
+	struct {
+		/* transport_addr_list
+		 *
+		 * Peer	       : A list of SCTP transport addresses that the
+		 * Transport   : peer is bound to. This information is derived
+		 * Address     : from the INIT or INIT ACK and is used to
+		 * List	       : associate an inbound packet with a given
+		 *	       : association. Normally this information is
+		 *	       : hashed or keyed for quick lookup and access
+		 *	       : of the TCB.
+		 *	       : The list is also initialized with the list
+		 *	       : of addresses passed with the sctp_connectx()
+		 *	       : call.
+		 *
+		 * It is a list of SCTP_transport's.
+		 */
+		struct list_head transport_addr_list;
+
+		/* rwnd
+		 *
+		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
+		 */
+		__u32 rwnd;
+
+		/* transport_count
+		 *
+		 * Peer        : A count of the number of peer addresses
+		 * Transport   : in the Peer Transport Address List.
+		 * Address     :
+		 * Count       :
+		 */
+		__u16 transport_count;
+
+		/* port
+		 *   The transport layer port number.
+		 */
+		__u16 port;
+
+		/* primary_path
+		 *
+		 * Primary     : This is the current primary destination
+		 * Path	       : transport address of the peer endpoint.  It
+		 *	       : may also specify a source transport address
+		 *	       : on this endpoint.
+		 *
+		 * All of these paths live on transport_addr_list.
+		 *
+		 * At the bakeoffs, we discovered that the intent of
+		 * primaryPath is that it only changes when the ULP
+		 * asks to have it changed.  We add the activePath to
+		 * designate the connection we are currently using to
+		 * transmit new data and most control chunks.
+		 */
+		struct sctp_transport *primary_path;
+
+		/* Cache the primary path address here, when we
+		 * need a an address for msg_name.
+		 */
+		union sctp_addr primary_addr;
+
+		/* active_path
+		 *   The path that we are currently using to
+		 *   transmit new data and most control chunks.
+		 */
+		struct sctp_transport *active_path;
+
+		/* retran_path
+		 *
+		 * RFC2960 6.4 Multi-homed SCTP Endpoints
+		 * ...
+		 * Furthermore, when its peer is multi-homed, an
+		 * endpoint SHOULD try to retransmit a chunk to an
+		 * active destination transport address that is
+		 * different from the last destination address to
+		 * which the DATA chunk was sent.
+		 */
+		struct sctp_transport *retran_path;
+
+		/* Pointer to last transport I have sent on.  */
+		struct sctp_transport *last_sent_to;
+
+		/* This is the last transport I have received DATA on.	*/
+		struct sctp_transport *last_data_from;
+
+		/*
+		 * Mapping  An array of bits or bytes indicating which out of
+		 * Array    order TSN's have been received (relative to the
+		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
+		 *	    order packets have been received, this array
+		 *	    will be set to all zero. This structure may be
+		 *	    in the form of a circular buffer or bit array.
+		 *
+		 * Last Rcvd   : This is the last TSN received in
+		 * TSN	       : sequence. This value is set initially by
+		 *	       : taking the peer's Initial TSN, received in
+		 *	       : the INIT or INIT ACK chunk, and subtracting
+		 *	       : one from it.
+		 *
+		 * Throughout most of the specification this is called the
+		 * "Cumulative TSN ACK Point".	In this case, we
+		 * ignore the advice in 12.2 in favour of the term
+		 * used in the bulk of the text.  This value is hidden
+		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
+		 */
+		struct sctp_tsnmap tsn_map;
+
+		/* This mask is used to disable sending the ASCONF chunk
+		 * with specified parameter to peer.
+		 */
+		__be16 addip_disabled_mask;
+
+		/* These are capabilities which our peer advertised.  */
+		__u8	ecn_capable:1,      /* Can peer do ECN? */
+			ipv4_address:1,     /* Peer understands IPv4 addresses? */
+			ipv6_address:1,     /* Peer understands IPv6 addresses? */
+			hostname_address:1, /* Peer understands DNS addresses? */
+			asconf_capable:1,   /* Does peer support ADDIP? */
+			prsctp_capable:1,   /* Can peer do PR-SCTP? */
+			auth_capable:1;     /* Is peer doing SCTP-AUTH? */
+
+		/* Ack State   : This flag indicates if the next received
+		 *             : packet is to be responded to with a
+		 *             : SACK. This is initializedto 0.  When a packet
+		 *             : is received it is incremented. If this value
+		 *             : reaches 2 or more, a SACK is sent and the
+		 *             : value is reset to 0. Note: This is used only
+		 *             : when no DATA chunks are received out of
+		 *             : order.  When DATA chunks are out of order,
+		 *             : SACK's are not delayed (see Section 6).
+		 */
+		__u8    sack_needed;     /* Do we need to sack the peer? */
+		__u32	sack_cnt;
+		__u32	sack_generation;
+
+		__u32   adaptation_ind;	 /* Adaptation Code point. */
+
+		struct sctp_inithdr_host i;
+		void *cookie;
+		int cookie_len;
+
+		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
+		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
+		 * Initial TSN Value minus 1
+		 */
+		__u32 addip_serial;
+
+		/* SCTP-AUTH: We need to know pears random number, hmac list
+		 * and authenticated chunk list.  All that is part of the
+		 * cookie and these are just pointers to those locations
+		 */
+		sctp_random_param_t *peer_random;
+		sctp_chunks_param_t *peer_chunks;
+		sctp_hmac_algo_param_t *peer_hmacs;
+	} peer;
+
+	/* State       : A state variable indicating what state the
+	 *	       : association is in, i.e. COOKIE-WAIT,
+	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
+	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
+	 *
+	 *		Note: No "CLOSED" state is illustrated since if a
+	 *		association is "CLOSED" its TCB SHOULD be removed.
+	 *
+	 *		In this implementation we DO have a CLOSED
+	 *		state which is used during initiation and shutdown.
+	 *
+	 *		State takes values from SCTP_STATE_*.
+	 */
+	sctp_state_t state;
+
+	/* Overall     : The overall association error count.
+	 * Error Count : [Clear this any time I get something.]
+	 */
+	int overall_error_count;
+
+	/* The cookie life I award for any cookie.  */
+	ktime_t cookie_life;
+
+	/* These are the association's initial, max, and min RTO values.
+	 * These values will be initialized by system defaults, but can
+	 * be modified via the SCTP_RTOINFO socket option.
+	 */
+	unsigned long rto_initial;
+	unsigned long rto_max;
+	unsigned long rto_min;
+
+	/* Maximum number of new data packets that can be sent in a burst.  */
+	int max_burst;
+
+	/* This is the max_retrans value for the association.  This value will
+	 * be initialized initialized from system defaults, but can be
+	 * modified by the SCTP_ASSOCINFO socket option.
+	 */
+	int max_retrans;
+
+	/* This is the partially failed retrans value for the transport
+	 * and will be initialized from the assocs value.  This can be
+	 * changed using the SCTP_PEER_ADDR_THLDS socket option
+	 */
+	int pf_retrans;
+
+	/* Maximum number of times the endpoint will retransmit INIT  */
+	__u16 max_init_attempts;
+
+	/* How many times have we resent an INIT? */
+	__u16 init_retries;
+
+	/* The largest timeout or RTO value to use in attempting an INIT */
+	unsigned long max_init_timeo;
+
+	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
+	 * the destination address every heartbeat interval. This value
+	 * will be inherited by all new transports.
+	 */
+	unsigned long hbinterval;
+
+	/* This is the max_retrans value for new transports in the
+	 * association.
+	 */
+	__u16 pathmaxrxt;
+
+	/* Flag that path mtu update is pending */
+	__u8   pmtu_pending;
+
+	/* Association : The smallest PMTU discovered for all of the
+	 * PMTU	       : peer's transport addresses.
+	 */
+	__u32 pathmtu;
+
+	/* Flags controlling Heartbeat, SACK delay, and Path MTU Discovery. */
+	__u32 param_flags;
+
+	__u32 sackfreq;
+	/* SACK delay timeout */
+	unsigned long sackdelay;
+
+	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
+	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
+
+	/* Transport to which SHUTDOWN chunk was last sent.  */
+	struct sctp_transport *shutdown_last_sent_to;
+
+	/* Transport to which INIT chunk was last sent.  */
+	struct sctp_transport *init_last_sent_to;
+
+	/* How many times have we resent a SHUTDOWN */
+	int shutdown_retries;
+
+	/* Next TSN    : The next TSN number to be assigned to a new
+	 *	       : DATA chunk.  This is sent in the INIT or INIT
+	 *	       : ACK chunk to the peer and incremented each
+	 *	       : time a DATA chunk is assigned a TSN
+	 *	       : (normally just prior to transmit or during
+	 *	       : fragmentation).
+	 */
+	__u32 next_tsn;
+
+	/*
+	 * Last Rcvd   : This is the last TSN received in sequence.  This value
+	 * TSN	       : is set initially by taking the peer's Initial TSN,
+	 *	       : received in the INIT or INIT ACK chunk, and
+	 *	       : subtracting one from it.
+	 *
+	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
+	 */
+
+	__u32 ctsn_ack_point;
+
+	/* PR-SCTP Advanced.Peer.Ack.Point */
+	__u32 adv_peer_ack_point;
+
+	/* Highest TSN that is acknowledged by incoming SACKs. */
+	__u32 highest_sacked;
+
+	/* TSN marking the fast recovery exit point */
+	__u32 fast_recovery_exit;
+
+	/* Flag to track the current fast recovery state */
+	__u8 fast_recovery;
+
+	/* The number of unacknowledged data chunks.  Reported through
+	 * the SCTP_STATUS sockopt.
+	 */
+	__u16 unack_data;
+
+	/* The total number of data chunks that we've had to retransmit
+	 * as the result of a T3 timer expiration
+	 */
+	__u32 rtx_data_chunks;
+
+	/* This is the association's receive buffer space.  This value is used
+	 * to set a_rwnd field in an INIT or a SACK chunk.
+	 */
+	__u32 rwnd;
+
+	/* This is the last advertised value of rwnd over a SACK chunk. */
+	__u32 a_rwnd;
+
+	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
+	 * to slop over a maximum of the association's frag_point.
+	 */
+	__u32 rwnd_over;
+
+	/* Keeps treack of rwnd pressure.  This happens when we have
+	 * a window, but not recevie buffer (i.e small packets).  This one
+	 * is releases slowly (1 PMTU at a time ).
+	 */
+	__u32 rwnd_press;
+
+	/* This is the sndbuf size in use for the association.
+	 * This corresponds to the sndbuf size for the association,
+	 * as specified in the sk->sndbuf.
+	 */
+	int sndbuf_used;
+
+	/* This is the amount of memory that this association has allocated
+	 * in the receive path at any given time.
+	 */
+	atomic_t rmem_alloc;
+
+	/* This is the wait queue head for send requests waiting on
+	 * the association sndbuf space.
+	 */
+	wait_queue_head_t	wait;
+
+	/* The message size at which SCTP fragmentation will occur. */
+	__u32 frag_point;
+	__u32 user_frag;
+
+	/* Counter used to count INIT errors. */
+	int init_err_counter;
+
+	/* Count the number of INIT cycles (for doubling timeout). */
+	int init_cycle;
+
+	/* Default send parameters. */
+	__u16 default_stream;
+	__u16 default_flags;
+	__u32 default_ppid;
+	__u32 default_context;
+	__u32 default_timetolive;
+
+	/* Default receive parameters */
+	__u32 default_rcv_context;
+
+	/* This tracks outbound ssn for a given stream.	 */
+	struct sctp_ssnmap *ssnmap;
+
+	/* All outbound chunks go through this structure.  */
+	struct sctp_outq outqueue;
+
+	/* A smart pipe that will handle reordering and fragmentation,
+	 * as well as handle passing events up to the ULP.
+	 */
+	struct sctp_ulpq ulpq;
+
+	/* Last TSN that caused an ECNE Chunk to be sent.  */
+	__u32 last_ecne_tsn;
+
+	/* Last TSN that caused a CWR Chunk to be sent.	 */
+	__u32 last_cwr_tsn;
+
+	/* How many duplicated TSNs have we seen?  */
+	int numduptsns;
+
+	/* These are to support
+	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
+	 *  and Enforcement of Flow and Message Limits"
+	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
+	 * or "ADDIP" for short.
+	 */
+
+
+
+	/* 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).
+	 *
+	 * [This is our one-and-only-one ASCONF in flight.  If we do
+	 * not have an ASCONF in flight, this is NULL.]
+	 */
+	struct sctp_chunk *addip_last_asconf;
+
+	/* ADDIP Section 5.2 Upon reception of an ASCONF Chunk.
+	 *
+	 * This is needed to implement itmes E1 - E4 of the updated
+	 * spec.  Here is the justification:
+	 *
+	 * Since the peer may bundle multiple ASCONF chunks toward us,
+	 * we now need the ability to cache multiple ACKs.  The section
+	 * describes in detail how they are cached and cleaned up.
+	 */
+	struct list_head asconf_ack_list;
+
+	/* These ASCONF chunks are waiting to be sent.
+	 *
+	 * These chunaks can't be pushed to outqueue until receiving
+	 * ASCONF_ACK for the previous ASCONF indicated by
+	 * addip_last_asconf, so as to guarantee that only one ASCONF
+	 * is in flight at any time.
+	 *
+	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
+	 *
+	 * In defining the ASCONF Chunk transfer procedures, it is
+	 * essential that these transfers MUST NOT cause congestion
+	 * within the network.	To achieve this, we place these
+	 * restrictions on the transfer 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).
+	 *
+	 *
+	 * [I really think this is EXACTLY the sort of intelligence
+	 *  which already resides in sctp_outq.	 Please move this
+	 *  queue and its supporting logic down there.	--piggy]
+	 */
+	struct list_head addip_chunk_list;
+
+	/* ADDIP Section 4.1 ASCONF Chunk Procedures
+	 *
+	 * A2) A serial number should be assigned to the Chunk. The
+	 * serial number SHOULD be a monotonically increasing
+	 * number. The serial number SHOULD be initialized at
+	 * the start of the association to the same value as the
+	 * Initial TSN and every time a new ASCONF chunk is created
+	 * it is incremented by one after assigning the serial number
+	 * to the newly created chunk.
+	 *
+	 * ADDIP
+	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
+	 *
+	 * Serial Number : 32 bits (unsigned integer)
+	 *
+	 * This value represents a Serial Number for the ASCONF
+	 * Chunk. The valid range of Serial Number is from 0 to
+	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
+	 * after reaching 4294967295.
+	 */
+	__u32 addip_serial;
+	int src_out_of_asoc_ok;
+	union sctp_addr *asconf_addr_del_pending;
+	struct sctp_transport *new_transport;
+
+	/* SCTP AUTH: list of the endpoint shared keys.  These
+	 * keys are provided out of band by the user applicaton
+	 * and can't change during the lifetime of the association
+	 */
+	struct list_head endpoint_shared_keys;
+
+	/* SCTP AUTH:
+	 * The current generated assocaition shared key (secret)
+	 */
+	struct sctp_auth_bytes *asoc_shared_key;
+
+	/* SCTP AUTH: hmac id of the first peer requested algorithm
+	 * that we support.
+	 */
+	__u16 default_hmac_id;
+
+	__u16 active_key_id;
+
+	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
+	     temp:1;		/* Is it a temporary association? */
+
+	struct sctp_priv_assoc_stats stats;
+};
+
+
+/* An eyecatcher for determining if we are really looking at an
+ * association data structure.
+ */
+enum {
+	SCTP_ASSOC_EYECATCHER = 0xa550c123,
+};
+
+/* Recover the outter association structure. */
+static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
+{
+	struct sctp_association *asoc;
+
+	asoc = container_of(base, struct sctp_association, base);
+	return asoc;
+}
+
+/* These are function signatures for manipulating associations.	 */
+
+
+struct sctp_association *
+sctp_association_new(const struct sctp_endpoint *, const struct sock *,
+		     sctp_scope_t scope, gfp_t gfp);
+void sctp_association_free(struct sctp_association *);
+void sctp_association_put(struct sctp_association *);
+void sctp_association_hold(struct sctp_association *);
+
+struct sctp_transport *sctp_assoc_choose_alter_transport(
+	struct sctp_association *, struct sctp_transport *);
+void sctp_assoc_update_retran_path(struct sctp_association *);
+struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
+					  const union sctp_addr *);
+int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
+			    const union sctp_addr *laddr);
+struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
+				     const union sctp_addr *address,
+				     const gfp_t gfp,
+				     const int peer_state);
+void sctp_assoc_del_peer(struct sctp_association *asoc,
+			 const union sctp_addr *addr);
+void sctp_assoc_rm_peer(struct sctp_association *asoc,
+			 struct sctp_transport *peer);
+void sctp_assoc_control_transport(struct sctp_association *,
+				  struct sctp_transport *,
+				  sctp_transport_cmd_t, sctp_sn_error_t);
+struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
+struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
+					   struct net *,
+					   const union sctp_addr *,
+					   const union sctp_addr *);
+void sctp_assoc_migrate(struct sctp_association *, struct sock *);
+void sctp_assoc_update(struct sctp_association *old,
+		       struct sctp_association *new);
+
+__u32 sctp_association_get_next_tsn(struct sctp_association *);
+
+void sctp_assoc_sync_pmtu(struct sock *, struct sctp_association *);
+void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned int);
+void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned int);
+void sctp_assoc_set_primary(struct sctp_association *,
+			    struct sctp_transport *);
+void sctp_assoc_del_nonprimary_peers(struct sctp_association *,
+				    struct sctp_transport *);
+int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
+				     sctp_scope_t, gfp_t);
+int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
+					 struct sctp_cookie*,
+					 gfp_t gfp);
+int sctp_assoc_set_id(struct sctp_association *, gfp_t);
+void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc);
+struct sctp_chunk *sctp_assoc_lookup_asconf_ack(
+					const struct sctp_association *asoc,
+					__be32 serial);
+void sctp_asconf_queue_teardown(struct sctp_association *asoc);
+
+int sctp_cmp_addr_exact(const union sctp_addr *ss1,
+			const union sctp_addr *ss2);
+struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
+
+/* A convenience structure to parse out SCTP specific CMSGs. */
+typedef struct sctp_cmsgs {
+	struct sctp_initmsg *init;
+	struct sctp_sndrcvinfo *srinfo;
+	struct sctp_sndinfo *sinfo;
+} sctp_cmsgs_t;
+
+/* Structure for tracking memory objects */
+typedef struct {
+	char *label;
+	atomic_t *counter;
+} sctp_dbg_objcnt_entry_t;
+
+#endif /* __sctp_structs_h__ */