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alistair23-linux/include/linux/dccp.h
Gerrit Renker 0c86962076 [DCCP]: Integrate state transitions for passive-close 
This adds the necessary state transitions for the two forms of passive-close

 * PASSIVE_CLOSE    - which is entered when a host   receives a Close;
 * PASSIVE_CLOSEREQ - which is entered when a client receives a CloseReq.

Here is a detailed account of what the patch does in each state.

1) Receiving CloseReq

  The pseudo-code in 8.5 says:

     Step 13: Process CloseReq
          If P.type == CloseReq and S.state < CLOSEREQ,
              Generate Close
              S.state := CLOSING
              Set CLOSING timer.

  This means we need to address what to do in CLOSED, LISTEN, REQUEST, RESPOND, PARTOPEN, and OPEN.

   * CLOSED:         silently ignore - it may be a late or duplicate CloseReq;
   * LISTEN/RESPOND: will not appear, since Step 7 is performed first (we know we are the client);
   * REQUEST:        perform Step 13 directly (no need to enqueue packet);
   * OPEN/PARTOPEN:  enter PASSIVE_CLOSEREQ so that the application has a chance to process unread data.

  When already in PASSIVE_CLOSEREQ, no second CloseReq is enqueued. In any other state, the CloseReq is ignored.
  I think that this offers some robustness against rare and pathological cases: e.g. a simultaneous close where
  the client sends a Close and the server a CloseReq. The client will then be retransmitting its Close until it
  gets the Reset, so ignoring the CloseReq while in state CLOSING is sane.

2) Receiving Close

  The code below from 8.5 is unconditional.

     Step 14: Process Close
          If P.type == Close,
              Generate Reset(Closed)
              Tear down connection
              Drop packet and return

  Thus we need to consider all states:
   * CLOSED:           silently ignore, since this can happen when a retransmitted or late Close arrives;
   * LISTEN:           dccp_rcv_state_process() will generate a Reset ("No Connection");
   * REQUEST:          perform Step 14 directly (no need to enqueue packet);
   * RESPOND:          dccp_check_req() will generate a Reset ("Packet Error") -- left it at that;
   * OPEN/PARTOPEN:    enter PASSIVE_CLOSE so that application has a chance to process unread data;
   * CLOSEREQ:         server performed active-close -- perform Step 14;
   * CLOSING:          simultaneous-close: use a tie-breaker to avoid message ping-pong (see comment);
   * PASSIVE_CLOSEREQ: ignore - the peer has a bug (sending first a CloseReq and now a Close);
   * TIMEWAIT:         packet is ignored.

   Note that the condition of receiving a packet in state CLOSED here is different from the condition "there
   is no socket for such a connection": the socket still exists, but its state indicates it is unusable.

   Last, dccp_finish_passive_close sets either DCCP_CLOSED or DCCP_CLOSING = TCP_CLOSING, so that
   sk_stream_wait_close() will wait for the final Reset (which will trigger CLOSING => CLOSED).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:55:13 -08:00

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#ifndef _LINUX_DCCP_H
#define _LINUX_DCCP_H
#include <linux/types.h>
#include <asm/byteorder.h>
/**
* struct dccp_hdr - generic part of DCCP packet header
*
* @dccph_sport - Relevant port on the endpoint that sent this packet
* @dccph_dport - Relevant port on the other endpoint
* @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
* @dccph_ccval - Used by the HC-Sender CCID
* @dccph_cscov - Parts of the packet that are covered by the Checksum field
* @dccph_checksum - Internet checksum, depends on dccph_cscov
* @dccph_x - 0 = 24 bit sequence number, 1 = 48
* @dccph_type - packet type, see DCCP_PKT_ prefixed macros
* @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
*/
struct dccp_hdr {
__be16 dccph_sport,
dccph_dport;
__u8 dccph_doff;
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 dccph_cscov:4,
dccph_ccval:4;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 dccph_ccval:4,
dccph_cscov:4;
#else
#error "Adjust your <asm/byteorder.h> defines"
#endif
__sum16 dccph_checksum;
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 dccph_x:1,
dccph_type:4,
dccph_reserved:3;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 dccph_reserved:3,
dccph_type:4,
dccph_x:1;
#else
#error "Adjust your <asm/byteorder.h> defines"
#endif
__u8 dccph_seq2;
__be16 dccph_seq;
};
/**
* struct dccp_hdr_ext - the low bits of a 48 bit seq packet
*
* @dccph_seq_low - low 24 bits of a 48 bit seq packet
*/
struct dccp_hdr_ext {
__be32 dccph_seq_low;
};
/**
* struct dccp_hdr_request - Connection initiation request header
*
* @dccph_req_service - Service to which the client app wants to connect
*/
struct dccp_hdr_request {
__be32 dccph_req_service;
};
/**
* struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
*
* @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
* @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
*/
struct dccp_hdr_ack_bits {
__be16 dccph_reserved1;
__be16 dccph_ack_nr_high;
__be32 dccph_ack_nr_low;
};
/**
* struct dccp_hdr_response - Connection initiation response header
*
* @dccph_resp_ack - 48 bit Acknowledgment Number Subheader (5.3)
* @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
*/
struct dccp_hdr_response {
struct dccp_hdr_ack_bits dccph_resp_ack;
__be32 dccph_resp_service;
};
/**
* struct dccp_hdr_reset - Unconditionally shut down a connection
*
* @dccph_reset_ack - 48 bit Acknowledgment Number Subheader (5.6)
* @dccph_reset_code - one of %dccp_reset_codes
* @dccph_reset_data - the Data 1 ... Data 3 fields from 5.6
*/
struct dccp_hdr_reset {
struct dccp_hdr_ack_bits dccph_reset_ack;
__u8 dccph_reset_code,
dccph_reset_data[3];
};
enum dccp_pkt_type {
DCCP_PKT_REQUEST = 0,
DCCP_PKT_RESPONSE,
DCCP_PKT_DATA,
DCCP_PKT_ACK,
DCCP_PKT_DATAACK,
DCCP_PKT_CLOSEREQ,
DCCP_PKT_CLOSE,
DCCP_PKT_RESET,
DCCP_PKT_SYNC,
DCCP_PKT_SYNCACK,
DCCP_PKT_INVALID,
};
#define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID
static inline unsigned int dccp_packet_hdr_len(const __u8 type)
{
if (type == DCCP_PKT_DATA)
return 0;
if (type == DCCP_PKT_DATAACK ||
type == DCCP_PKT_ACK ||
type == DCCP_PKT_SYNC ||
type == DCCP_PKT_SYNCACK ||
type == DCCP_PKT_CLOSE ||
type == DCCP_PKT_CLOSEREQ)
return sizeof(struct dccp_hdr_ack_bits);
if (type == DCCP_PKT_REQUEST)
return sizeof(struct dccp_hdr_request);
if (type == DCCP_PKT_RESPONSE)
return sizeof(struct dccp_hdr_response);
return sizeof(struct dccp_hdr_reset);
}
enum dccp_reset_codes {
DCCP_RESET_CODE_UNSPECIFIED = 0,
DCCP_RESET_CODE_CLOSED,
DCCP_RESET_CODE_ABORTED,
DCCP_RESET_CODE_NO_CONNECTION,
DCCP_RESET_CODE_PACKET_ERROR,
DCCP_RESET_CODE_OPTION_ERROR,
DCCP_RESET_CODE_MANDATORY_ERROR,
DCCP_RESET_CODE_CONNECTION_REFUSED,
DCCP_RESET_CODE_BAD_SERVICE_CODE,
DCCP_RESET_CODE_TOO_BUSY,
DCCP_RESET_CODE_BAD_INIT_COOKIE,
DCCP_RESET_CODE_AGGRESSION_PENALTY,
DCCP_MAX_RESET_CODES /* Leave at the end! */
};
/* DCCP options */
enum {
DCCPO_PADDING = 0,
DCCPO_MANDATORY = 1,
DCCPO_MIN_RESERVED = 3,
DCCPO_MAX_RESERVED = 31,
DCCPO_CHANGE_L = 32,
DCCPO_CONFIRM_L = 33,
DCCPO_CHANGE_R = 34,
DCCPO_CONFIRM_R = 35,
DCCPO_NDP_COUNT = 37,
DCCPO_ACK_VECTOR_0 = 38,
DCCPO_ACK_VECTOR_1 = 39,
DCCPO_TIMESTAMP = 41,
DCCPO_TIMESTAMP_ECHO = 42,
DCCPO_ELAPSED_TIME = 43,
DCCPO_MAX = 45,
DCCPO_MIN_CCID_SPECIFIC = 128,
DCCPO_MAX_CCID_SPECIFIC = 255,
};
/* DCCP CCIDS */
enum {
DCCPC_CCID2 = 2,
DCCPC_CCID3 = 3,
};
/* DCCP features (RFC 4340 section 6.4) */
enum {
DCCPF_RESERVED = 0,
DCCPF_CCID = 1,
DCCPF_SHORT_SEQNOS = 2, /* XXX: not yet implemented */
DCCPF_SEQUENCE_WINDOW = 3,
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, /* XXX: not yet implemented */
/* 10-127 reserved */
DCCPF_MIN_CCID_SPECIFIC = 128,
DCCPF_MAX_CCID_SPECIFIC = 255,
};
/* 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_PACKET_SIZE 1 /* XXX deprecated, without effect */
#define DCCP_SOCKOPT_SERVICE 2
#define DCCP_SOCKOPT_CHANGE_L 3
#define DCCP_SOCKOPT_CHANGE_R 4
#define DCCP_SOCKOPT_GET_CUR_MPS 5
#define DCCP_SOCKOPT_SEND_CSCOV 10
#define DCCP_SOCKOPT_RECV_CSCOV 11
#define DCCP_SOCKOPT_CCID_RX_INFO 128
#define DCCP_SOCKOPT_CCID_TX_INFO 192
/* maximum number of services provided on the same listening port */
#define DCCP_SERVICE_LIST_MAX_LEN 32
#ifdef __KERNEL__
#include <linux/in.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/uio.h>
#include <linux/workqueue.h>
#include <net/inet_connection_sock.h>
#include <net/inet_sock.h>
#include <net/inet_timewait_sock.h>
#include <net/tcp_states.h>
enum dccp_state {
DCCP_OPEN = TCP_ESTABLISHED,
DCCP_REQUESTING = TCP_SYN_SENT,
DCCP_LISTEN = TCP_LISTEN,
DCCP_RESPOND = TCP_SYN_RECV,
/*
* States involved in closing a DCCP connection:
* 1) ACTIVE_CLOSEREQ is entered by a server sending a CloseReq.
*
* 2) CLOSING can have three different meanings (RFC 4340, 8.3):
* a. Client has performed active-close, has sent a Close to the server
* from state OPEN or PARTOPEN, and is waiting for the final Reset
* (in this case, SOCK_DONE == 1).
* b. Client is asked to perform passive-close, by receiving a CloseReq
* in (PART)OPEN state. It sends a Close and waits for final Reset
* (in this case, SOCK_DONE == 0).
* c. Server performs an active-close as in (a), keeps TIMEWAIT state.
*
* 3) The following intermediate states are employed to give passively
* closing nodes a chance to process their unread data:
* - PASSIVE_CLOSE (from OPEN => CLOSED) and
* - PASSIVE_CLOSEREQ (from (PART)OPEN to CLOSING; case (b) above).
*/
DCCP_ACTIVE_CLOSEREQ = TCP_FIN_WAIT1,
DCCP_PASSIVE_CLOSE = TCP_CLOSE_WAIT, /* any node receiving a Close */
DCCP_CLOSING = TCP_CLOSING,
DCCP_TIME_WAIT = TCP_TIME_WAIT,
DCCP_CLOSED = TCP_CLOSE,
DCCP_PARTOPEN = TCP_MAX_STATES,
DCCP_PASSIVE_CLOSEREQ, /* clients receiving CloseReq */
DCCP_MAX_STATES
};
#define DCCP_STATE_MASK 0x1f
enum {
DCCPF_OPEN = TCPF_ESTABLISHED,
DCCPF_REQUESTING = TCPF_SYN_SENT,
DCCPF_LISTEN = TCPF_LISTEN,
DCCPF_RESPOND = TCPF_SYN_RECV,
DCCPF_ACTIVE_CLOSEREQ = TCPF_FIN_WAIT1,
DCCPF_CLOSING = TCPF_CLOSING,
DCCPF_TIME_WAIT = TCPF_TIME_WAIT,
DCCPF_CLOSED = TCPF_CLOSE,
DCCPF_PARTOPEN = (1 << DCCP_PARTOPEN),
};
static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
{
return (struct dccp_hdr *)skb_transport_header(skb);
}
static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen)
{
skb_push(skb, headlen);
skb_reset_transport_header(skb);
return memset(skb_transport_header(skb), 0, headlen);
}
static inline struct dccp_hdr_ext *dccp_hdrx(const struct dccp_hdr *dh)
{
return (struct dccp_hdr_ext *)((unsigned char *)dh + sizeof(*dh));
}
static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
{
return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
}
static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);
return __dccp_basic_hdr_len(dh);
}
static inline __u64 dccp_hdr_seq(const struct dccp_hdr *dh)
{
__u64 seq_nr = ntohs(dh->dccph_seq);
if (dh->dccph_x != 0)
seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(dh)->dccph_seq_low);
else
seq_nr += (u32)dh->dccph_seq2 << 16;
return seq_nr;
}
static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb)
{
return (struct dccp_hdr_request *)(skb_transport_header(skb) +
dccp_basic_hdr_len(skb));
}
static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb)
{
return (struct dccp_hdr_ack_bits *)(skb_transport_header(skb) +
dccp_basic_hdr_len(skb));
}
static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb)
{
const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb);
return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + ntohl(dhack->dccph_ack_nr_low);
}
static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb)
{
return (struct dccp_hdr_response *)(skb_transport_header(skb) +
dccp_basic_hdr_len(skb));
}
static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
{
return (struct dccp_hdr_reset *)(skb_transport_header(skb) +
dccp_basic_hdr_len(skb));
}
static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh)
{
return __dccp_basic_hdr_len(dh) +
dccp_packet_hdr_len(dh->dccph_type);
}
static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
{
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
#define DCCP_NDP_LIMIT 0xFFFFFF
/**
* 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);
extern int dccp_parse_options(struct sock *sk, struct sk_buff *skb);
struct dccp_request_sock {
struct inet_request_sock dreq_inet_rsk;
__u64 dreq_iss;
__u64 dreq_isr;
__be32 dreq_service;
};
static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
{
return (struct dccp_request_sock *)req;
}
extern struct inet_timewait_death_row dccp_death_row;
struct dccp_options_received {
u32 dccpor_ndp; /* only 24 bits */
u32 dccpor_timestamp;
u32 dccpor_timestamp_echo;
u32 dccpor_elapsed_time;
};
struct ccid;
enum dccp_role {
DCCP_ROLE_UNDEFINED,
DCCP_ROLE_LISTEN,
DCCP_ROLE_CLIENT,
DCCP_ROLE_SERVER,
};
struct dccp_service_list {
__u32 dccpsl_nr;
__be32 dccpsl_list[0];
};
#define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)
#define DCCP_SERVICE_CODE_IS_ABSENT 0
static inline int dccp_list_has_service(const struct dccp_service_list *sl,
const __be32 service)
{
if (likely(sl != NULL)) {
u32 i = sl->dccpsl_nr;
while (i--)
if (sl->dccpsl_list[i] == service)
return 1;
}
return 0;
}
struct dccp_ackvec;
/**
* struct dccp_sock - DCCP socket state
*
* @dccps_swl - sequence number window low
* @dccps_swh - sequence number window high
* @dccps_awl - acknowledgement number window low
* @dccps_awh - acknowledgement number window high
* @dccps_iss - initial sequence number sent
* @dccps_isr - initial sequence number received
* @dccps_osr - first OPEN sequence number received
* @dccps_gss - greatest sequence number sent
* @dccps_gsr - greatest valid sequence number received
* @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss
* @dccps_service - first (passive sock) or unique (active sock) service code
* @dccps_service_list - second .. last service code on passive socket
* @dccps_timestamp_time - time of latest TIMESTAMP option
* @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option
* @dccps_l_ack_ratio - feature-local Ack Ratio
* @dccps_r_ack_ratio - feature-remote Ack Ratio
* @dccps_pcslen - sender partial checksum coverage (via sockopt)
* @dccps_pcrlen - receiver partial checksum coverage (via sockopt)
* @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_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_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_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 {
/* inet_connection_sock has to be the first member of dccp_sock */
struct inet_connection_sock dccps_inet_connection;
#define dccps_syn_rtt dccps_inet_connection.icsk_ack.lrcvtime
__u64 dccps_swl;
__u64 dccps_swh;
__u64 dccps_awl;
__u64 dccps_awh;
__u64 dccps_iss;
__u64 dccps_isr;
__u64 dccps_osr;
__u64 dccps_gss;
__u64 dccps_gsr;
__u64 dccps_gar;
__be32 dccps_service;
struct dccp_service_list *dccps_service_list;
ktime_t dccps_timestamp_time;
__u32 dccps_timestamp_echo;
__u16 dccps_l_ack_ratio;
__u16 dccps_r_ack_ratio;
__u16 dccps_pcslen;
__u16 dccps_pcrlen;
unsigned long dccps_ndp_count;
__u32 dccps_mss_cache;
unsigned long dccps_rate_last;
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;
enum dccp_role dccps_role:2;
__u8 dccps_hc_rx_insert_options:1;
__u8 dccps_hc_tx_insert_options:1;
struct timer_list dccps_xmit_timer;
};
static inline struct dccp_sock *dccp_sk(const struct sock *sk)
{
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) {
case DCCP_ROLE_UNDEFINED: return "undefined";
case DCCP_ROLE_LISTEN: return "listen";
case DCCP_ROLE_SERVER: return "server";
case DCCP_ROLE_CLIENT: return "client";
}
return NULL;
}
#endif /* __KERNEL__ */
#endif /* _LINUX_DCCP_H */
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