structs.h

h内核

/* 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 ipfragok);
	int		(*setsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 int optlen);
	int		(*getsockopt)	(struct sock *sk,
					 int level,
					 int optname,
					 char __user *optval,
					 int __user *optlen);
	struct dst_entry *(*get_dst)	(struct sctp_association *asoc,
					 union sctp_addr *daddr,
					 union sctp_addr *saddr);
	void		(*get_saddr)	(struct sctp_association *asoc,
					 struct dst_entry *dst,
					 union sctp_addr *daddr,
					 union sctp_addr *saddr);
	void		(*copy_addrlist) (struct list_head *,
					  struct net_device *);
	void		(*dst_saddr)	(union sctp_addr *saddr,
					 struct dst_entry *dst,
					 unsigned short port);
	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		(*to_sk_saddr)	(union sctp_addr *,
					 struct sock *sk);
	void		(*to_sk_daddr)	(union sctp_addr *,
					 struct sock *sk);
	void		(*from_addr_param) (union sctp_addr *,
					    union sctp_addr_param *,
					    __u16 port, int iif);	
	int		(*to_addr_param) (const union sctp_addr *,
					  union sctp_addr_param *); 
	int		(*addr_valid)	(union sctp_addr *,
					 struct sctp_sock *);
	sctp_scope_t	(*scope) (union sctp_addr *);
	void		(*inaddr_any)	(union sctp_addr *, unsigned short);
	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);
	__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 *, __u16 *);
	struct sock *(*create_accept_sk) (struct sock *sk,
					  struct sctp_association *asoc);
	void (*addr_v4map) (struct sctp_sock *, union sctp_addr *);
	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;
	/* Chunks that have been transmitted. */
	struct list_head track;
	/* 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;
	char send_failed;
	/* Control whether chunks from this message can be abandoned. */
	char can_abandon;
};

struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
					    struct sctp_sndrcvinfo *,
					    struct msghdr *, int len);
void sctp_datamsg_put(struct sctp_datamsg *);
void sctp_datamsg_free(struct sctp_datamsg *);
void sctp_datamsg_track(struct sctp_chunk *);
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 {
	/* These first three elements MUST PRECISELY match the first
	 * three elements of struct sk_buff.  This allows us to reuse
	 * all the skb_* queue management functions.
	 */
	struct sctp_chunk *next;
	struct sctp_chunk *prev;
	struct sk_buff_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;
	} 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;

	__u8 rtt_in_progress;	/* Is this chunk used for RTT calculation? */
	__u8 resent;		/* Has this chunk ever been retransmitted. */
	__u8 has_tsn;		/* Does this chunk have a TSN yet? */
	__u8 has_ssn;		/* Does this chunk have a SSN yet? */
	__u8 singleton;		/* Was this the only chunk in the packet? */
	__u8 end_of_packet;	/* Was this the last chunk in the packet? */
	__u8 ecn_ce_done;	/* Have we processed the ECN CE bit? */
	__u8 pdiscard;		/* Discard the whole packet now? */
	__u8 tsn_gap_acked;	/* Is this chunk acked by a GAP ACK? */
	__u8 fast_retransmit;	 /* Is this chunk fast retransmitted? */
	__u8 tsn_missing_report; /* Data chunk missing counter. */
};

void sctp_chunk_hold(struct sctp_chunk *);
void sctp_chunk_put(struct sctp_chunk *);
int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
			  struct iovec *data);
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);

/* This is a structure for holding either an IPv6 or an IPv4 address.  */
/* sin_family -- AF_INET or AF_INET6
 * sin_port -- ordinary port number
 * sin_addr -- cast to either (struct in_addr) or (struct in6_addr)
 */
struct sctp_sockaddr_entry {
	struct list_head list;
	union sctp_addr a;
};

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 sk_buff_head chunks;

	/* 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;

	/* This packet contains a COOKIE-ECHO chunk. */
	char has_cookie_echo;

	/* This packet containsa SACK chunk. */
	char has_sack;

	/* SCTP cannot fragment this packet. So let ip fragment it. */
	char ipfragok;

	int malloced;
};

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 *);
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;
	int	 dead;

	/* 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:
	 */
	__u32 rtt;		/* This is the most recent RTT.	 */

	/* RTO	       : The current retransmission timeout value.  */
	__u32 rto;

	/* RTTVAR      : The current RTT variation.  */
	__u32 rttvar;

	/* SRTT	       : The current smoothed round trip time.	*/
	__u32 srtt;

	/* 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.
	 */
	int rto_pending;

	/*
	 * 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;

	/* PMTU	      : The current known path MTU.  */
	__u32 pmtu;

	/* Destination */
	struct dst_entry *dst;
	/* Source address. */
	union sctp_addr saddr;

	/* When was the last time(in jiffies) that a data packet was sent on
	 * this transport?  This is used to adjust the cwnd when the transport
	 * becomes inactive.
	 */
	unsigned long last_time_used;

	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
	 * the destination address every heartbeat interval.
	 */
	int hb_interval;

	/* When was the last time (in jiffies) that we heard from this
	 * transport?  We use this to pick new active and retran paths.
	 */
	unsigned long 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;

	/* active      : The current active state of this destination,
	 *	       :  i.e. DOWN, UP, etc.
	 */
	int active;

	/* hb_allowed  : The current heartbeat state of this destination,
	 *	       :  i.e. ALLOW-HB, NO-HEARTBEAT, etc.
	 */
	int hb_allowed;

	/* These are the error stats for this destination.  */

	/* Error count : The current error count for this destination.	*/
	unsigned short error_count;

	/* This is the max_retrans value for the transport and will
	 * be initialized to proto.max_retrans.path.  This can be changed