This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp"

Socket options

==============

DCCP_SOCKOPT_QPOLICY_ID sets the dequeuing policy for outgoing packets. It takes

a policy ID as argument and can only be set before the connection (i.e. changes

during an established connection are not supported). Currently, two policies are

defined: the "simple" policy (DCCPQ_POLICY_SIMPLE), which does nothing special,

and a priority-based variant (DCCPQ_POLICY_PRIO). The latter allows to pass an

u32 priority value as ancillary data to sendmsg(), where higher numbers indicate

a higher packet priority (similar to SO_PRIORITY). This ancillary data needs to

be formatted using a cmsg(3) message header filled in as follows:

	cmsg->cmsg_level = SOL_DCCP;

	cmsg->cmsg_type	 = DCCP_SCM_PRIORITY;

	cmsg->cmsg_len	 = CMSG_LEN(sizeof(uint32_t));	/* or CMSG_LEN(4) */

DCCP_SOCKOPT_QPOLICY_TXQLEN sets the maximum length of the output queue. A zero

value is always interpreted as unbounded queue length. If different from zero,

the interpretation of this parameter depends on the current dequeuing policy

(see above): the "simple" policy will enforce a fixed queue size by returning

EAGAIN, whereas the "prio" policy enforces a fixed queue length by dropping the

lowest-priority packet first. The default value for this parameter is

initialised from /proc/sys/net/dccp/default/tx_qlen.

DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of

service codes (RFC 4340, sec. 8.1.2); if this socket option is not set,

DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet

size (application payload size) in bytes, see RFC 4340, section 14.

DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs

supported by the endpoint (see include/linux/dccp.h for symbolic constants).

The caller needs to provide a sufficiently large (> 2) array of type uint8_t.

DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same

time, combining the operation of the next two socket options. This option is

preferrable over the latter two, since often applications will use the same

type of CCID for both directions; and mixed use of CCIDs is not currently well

understood. This socket option takes as argument at least one uint8_t value, or

an array of uint8_t values, which must match available CCIDS (see above). CCIDs

must be registered on the socket before calling connect() or listen().

DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or sets

the preference list for the TX CCID, using the same format as DCCP_SOCKOPT_CCID.

Please note that the getsockopt argument type here is `int', not uint8_t.

DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID.

DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold

timewait state when closing the connection (RFC 4340, 8.3). The usual case is

that the closing server sends a CloseReq, whereupon the client holds timewait

	importance for retransmitted acknowledgments and feature negotiation,

	data packets are never retransmitted. Analogue of tcp_retries2.

send_ndp = 1

	Whether or not to send NDP count options (sec. 7.7.2).

send_ackvec = 1

	Whether or not to send Ack Vector options (sec. 11.5).

ack_ratio = 2

	The default Ack Ratio (sec. 11.3) to use.

tx_ccid = 2

	Default CCID for the sender-receiver half-connection. Depending on the

	choice of CCID, the Send Ack Vector feature is enabled automatically.

	Default CCID for the sender-receiver half-connection.

rx_ccid = 2

	Default CCID for the receiver-sender half-connection; see tx_ccid.

	Default CCID for the receiver-sender half-connection.

seq_window = 100

	The initial sequence window (sec. 7.5.2) of the sender. This influences

	the local ackno validity and the remote seqno validity windows (7.5.1).

	The initial sequence window (sec. 7.5.2).

tx_qlen = 5

	The size of the transmit buffer in packets. A value of 0 corresponds

	DCCPO_TIMESTAMP_ECHO = 42,

	DCCPO_ELAPSED_TIME = 43,

	DCCPO_MAX = 45,

	DCCPO_MIN_RX_CCID_SPECIFIC = 128,	/* from sender to receiver */

	DCCPO_MAX_RX_CCID_SPECIFIC = 191,

	DCCPO_MIN_TX_CCID_SPECIFIC = 192,	/* from receiver to sender */

	DCCPO_MAX_TX_CCID_SPECIFIC = 255,

	DCCPO_MIN_CCID_SPECIFIC = 128,

	DCCPO_MAX_CCID_SPECIFIC = 255,

};

/* maximum size of a single TLV-encoded DCCP option (sans type/len bytes) */

#define DCCP_SINGLE_OPT_MAXLEN	253

/* DCCP CCIDS */

enum {

};

/* DCCP features (RFC 4340 section 6.4) */

enum dccp_feature_numbers {

enum {

	DCCPF_RESERVED = 0,

	DCCPF_CCID = 1,

	DCCPF_SHORT_SEQNOS = 2,

	DCCPF_SHORT_SEQNOS = 2,		/* XXX: not yet implemented */

	DCCPF_SEQUENCE_WINDOW = 3,

	DCCPF_ECN_INCAPABLE = 4,

	DCCPF_ECN_INCAPABLE = 4,	/* XXX: not yet implemented */

	DCCPF_ACK_RATIO = 5,

	DCCPF_SEND_ACK_VECTOR = 6,

	DCCPF_SEND_NDP_COUNT = 7,

	DCCPF_MIN_CSUM_COVER = 8,

	DCCPF_DATA_CHECKSUM = 9,

	DCCPF_DATA_CHECKSUM = 9,	/* XXX: not yet implemented */

	/* 10-127 reserved */

	DCCPF_MIN_CCID_SPECIFIC = 128,

	DCCPF_SEND_LEV_RATE = 192,	/* RFC 4342, sec. 8.4 */

	DCCPF_MAX_CCID_SPECIFIC = 255,

};

/* DCCP socket control message types for cmsg */

enum dccp_cmsg_type {

	DCCP_SCM_PRIORITY = 1,

	DCCP_SCM_QPOLICY_MAX = 0xFFFF,

	/* ^-- Up to here reserved exclusively for qpolicy parameters */

	DCCP_SCM_MAX

};

/* DCCP priorities for outgoing/queued packets */

enum dccp_packet_dequeueing_policy {

	DCCPQ_POLICY_SIMPLE,

	DCCPQ_POLICY_PRIO,

	DCCPQ_POLICY_MAX

/* this structure is argument to DCCP_SOCKOPT_CHANGE_X */

struct dccp_so_feat {

	__u8 dccpsf_feat;

	__u8 __user *dccpsf_val;

	__u8 dccpsf_len;

};

/* DCCP socket options */

#define DCCP_SOCKOPT_SERVER_TIMEWAIT	6

#define DCCP_SOCKOPT_SEND_CSCOV		10

#define DCCP_SOCKOPT_RECV_CSCOV		11

#define DCCP_SOCKOPT_AVAILABLE_CCIDS	12

#define DCCP_SOCKOPT_CCID		13

#define DCCP_SOCKOPT_TX_CCID		14

#define DCCP_SOCKOPT_RX_CCID		15

#define DCCP_SOCKOPT_QPOLICY_ID		16

#define DCCP_SOCKOPT_QPOLICY_TXQLEN	17

#define DCCP_SOCKOPT_CCID_RX_INFO	128

#define DCCP_SOCKOPT_CCID_TX_INFO	192

	return __dccp_hdr_len(dccp_hdr(skb));

}

/* initial values for each feature */

#define DCCPF_INITIAL_SEQUENCE_WINDOW		100

#define DCCPF_INITIAL_ACK_RATIO			2

#define DCCPF_INITIAL_CCID			DCCPC_CCID2

#define DCCPF_INITIAL_SEND_ACK_VECTOR		1

/* FIXME: for now we're default to 1 but it should really be 0 */

#define DCCPF_INITIAL_SEND_NDP_COUNT		1

/**

  * struct dccp_minisock - Minimal DCCP connection representation

  *

  * Will be used to pass the state from dccp_request_sock to dccp_sock.

  *

  * @dccpms_sequence_window - Sequence Window Feature (section 7.5.2)

  * @dccpms_ccid - Congestion Control Id (CCID) (section 10)

  * @dccpms_send_ack_vector - Send Ack Vector Feature (section 11.5)

  * @dccpms_send_ndp_count - Send NDP Count Feature (7.7.2)

  * @dccpms_ack_ratio - Ack Ratio Feature (section 11.3)

  * @dccpms_pending - List of features being negotiated

  * @dccpms_conf -

  */

struct dccp_minisock {

	__u64			dccpms_sequence_window;

	__u8			dccpms_rx_ccid;

	__u8			dccpms_tx_ccid;

	__u8			dccpms_send_ack_vector;

	__u8			dccpms_send_ndp_count;

	__u8			dccpms_ack_ratio;

	struct list_head	dccpms_pending;

	struct list_head	dccpms_conf;

};

struct dccp_opt_conf {

	__u8			*dccpoc_val;

	__u8			dccpoc_len;

};

struct dccp_opt_pend {

	struct list_head	dccpop_node;

	__u8			dccpop_type;

	__u8			dccpop_feat;

	__u8		        *dccpop_val;

	__u8			dccpop_len;

	int			dccpop_conf;

	struct dccp_opt_conf    *dccpop_sc;

};

extern void dccp_minisock_init(struct dccp_minisock *dmsk);

/**

 * struct dccp_request_sock  -  represent DCCP-specific connection request

 * @dreq_inet_rsk: structure inherited from

 * @dreq_iss: initial sequence number sent on the Response (RFC 4340, 7.1)

 * @dreq_isr: initial sequence number received on the Request

 * @dreq_service: service code present on the Request (there is just one)

 * @dreq_featneg: feature negotiation options for this connection

 * The following two fields are analogous to the ones in dccp_sock:

 * @dreq_timestamp_echo: last received timestamp to echo (13.1)

 * @dreq_timestamp_echo: the time of receiving the last @dreq_timestamp_echo

	__u64			 dreq_iss;

	__u64			 dreq_isr;

	__be32			 dreq_service;

	struct list_head	 dreq_featneg;

	__u32			 dreq_timestamp_echo;

	__u32			 dreq_timestamp_time;

};

 * @dccps_timestamp_time - time of receiving latest @dccps_timestamp_echo

 * @dccps_l_ack_ratio - feature-local Ack Ratio

 * @dccps_r_ack_ratio - feature-remote Ack Ratio

 * @dccps_l_seq_win - local Sequence Window (influences ack number validity)

 * @dccps_r_seq_win - remote Sequence Window (influences seq number validity)

 * @dccps_pcslen - sender   partial checksum coverage (via sockopt)

 * @dccps_pcrlen - receiver partial checksum coverage (via sockopt)

 * @dccps_send_ndp_count - local Send NDP Count feature (7.7.2)

 * @dccps_ndp_count - number of Non Data Packets since last data packet

 * @dccps_mss_cache - current value of MSS (path MTU minus header sizes)

 * @dccps_rate_last - timestamp for rate-limiting DCCP-Sync (RFC 4340, 7.5.4)

 * @dccps_featneg - tracks feature-negotiation state (mostly during handshake)

 * @dccps_minisock - associated minisock (accessed via dccp_msk)

 * @dccps_hc_rx_ackvec - rx half connection ack vector

 * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving half-connection)

 * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection)

 * @dccps_options_received - parsed set of retrieved options

 * @dccps_qpolicy - TX dequeueing policy, one of %dccp_packet_dequeueing_policy

 * @dccps_tx_qlen - maximum length of the TX queue

 * @dccps_role - role of this sock, one of %dccp_role

 * @dccps_hc_rx_insert_options - receiver wants to add options when acking

 * @dccps_hc_tx_insert_options - sender wants to add options when sending

 * @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3)

 * @dccps_sync_scheduled - flag which signals "send out-of-band message soon"

 * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets

 * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing)

 * @dccps_xmit_timer - timer for when CCID is not ready to send

 * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)

 */

struct dccp_sock {

	__u32				dccps_timestamp_time;

	__u16				dccps_l_ack_ratio;

	__u16				dccps_r_ack_ratio;

	__u64				dccps_l_seq_win:48;

	__u64				dccps_r_seq_win:48;

	__u8				dccps_pcslen:4;

	__u8				dccps_pcrlen:4;

	__u8				dccps_send_ndp_count:1;

	__u16				dccps_pcslen;

	__u16				dccps_pcrlen;

	__u64				dccps_ndp_count:48;

	unsigned long			dccps_rate_last;

	struct list_head		dccps_featneg;

	struct dccp_minisock		dccps_minisock;

	struct dccp_ackvec		*dccps_hc_rx_ackvec;

	struct ccid			*dccps_hc_rx_ccid;

	struct ccid			*dccps_hc_tx_ccid;

	struct dccp_options_received	dccps_options_received;

	__u8				dccps_qpolicy;

	__u32				dccps_tx_qlen;

	enum dccp_role			dccps_role:2;

	__u8				dccps_hc_rx_insert_options:1;

	__u8				dccps_hc_tx_insert_options:1;

	__u8				dccps_server_timewait:1;

	__u8				dccps_sync_scheduled:1;

	struct tasklet_struct		dccps_xmitlet;

	struct timer_list		dccps_xmit_timer;

};

	return (struct dccp_sock *)sk;

}

static inline struct dccp_minisock *dccp_msk(const struct sock *sk)

{

	return (struct dccp_minisock *)&dccp_sk(sk)->dccps_minisock;

}

static inline const char *dccp_role(const struct sock *sk)

{

	switch (dccp_sk(sk)->dccps_role) {

/* Use define here intentionally to get WARN_ON location shown at the caller */

#define tcp_verify_left_out(tp)	WARN_ON(tcp_left_out(tp) > tp->packets_out)

/*

 * Convert RFC3390 larger initial windows into an equivalent number of packets.

 *

 * John Heffner states:

 *

 *	The RFC specifies a window of no more than 4380 bytes

 *	unless 2*MSS > 4380.  Reading the pseudocode in the RFC

 *	is a bit misleading because they use a clamp at 4380 bytes

 *	rather than a multiplier in the relevant range.

 */

static inline u32 rfc3390_bytes_to_packets(const u32 bytes)

{

	return bytes <= 1095 ? 4 : (bytes > 1460 ? 2 : 3);

}

extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);

extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);

	def_tristate y if (IP_DCCP = y && INET_DIAG = y)

	def_tristate m

config IP_DCCP_ACKVEC

	bool

source "net/dccp/ccids/Kconfig"

menu "DCCP Kernel Hacking"

obj-$(CONFIG_IP_DCCP) += dccp.o dccp_ipv4.o

dccp-y := ccid.o feat.o input.o minisocks.o options.o \

	  qpolicy.o output.o proto.o timer.o ackvec.o

dccp-y := ccid.o feat.o input.o minisocks.o options.o output.o proto.o timer.o

dccp_ipv4-y := ipv4.o

obj-$(subst y,$(CONFIG_IP_DCCP),$(CONFIG_IPV6)) += dccp_ipv6.o

dccp_ipv6-y := ipv6.o

dccp-$(CONFIG_IP_DCCP_ACKVEC) += ackvec.o

obj-$(CONFIG_INET_DCCP_DIAG) += dccp_diag.o

obj-$(CONFIG_NET_DCCPPROBE) += dccp_probe.o