/*
* net/dccp/ackvec.h
*
- * An implementation of Ack Vectors for the DCCP protocol
- * Copyright (c) 2007 University of Aberdeen, Scotland, UK
+ * An implementation of the DCCP protocol
* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
+ *
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
#include <linux/dccp.h>
#include <linux/compiler.h>
+#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/types.h>
-/*
- * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN,
- * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1
- * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives
- * more headroom if Ack Ratio is higher or when the sender acknowledges slowly.
- * The maximum value is bounded by the u16 types for indices and functions.
- */
-#define DCCPAV_NUM_ACKVECS 2
-#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
-
-/* Estimated minimum average Ack Vector length - used for updating MPS */
-#define DCCPAV_MIN_OPTLEN 16
-
-enum dccp_ackvec_states {
- DCCPAV_RECEIVED = 0x00,
- DCCPAV_ECN_MARKED = 0x40,
- DCCPAV_RESERVED = 0x80,
- DCCPAV_NOT_RECEIVED = 0xC0
-};
-#define DCCPAV_MAX_RUNLEN 0x3F
+/* We can spread an ack vector across multiple options */
+#define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2)
-static inline u8 dccp_ackvec_runlen(const u8 *cell)
-{
- return *cell & DCCPAV_MAX_RUNLEN;
-}
+#define DCCP_ACKVEC_STATE_RECEIVED 0
+#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6)
+#define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6)
-static inline u8 dccp_ackvec_state(const u8 *cell)
-{
- return *cell & ~DCCPAV_MAX_RUNLEN;
-}
+#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */
+#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */
-/** struct dccp_ackvec - Ack Vector main data structure
+/** struct dccp_ackvec - ack vector
+ *
+ * This data structure is the one defined in RFC 4340, Appendix A.
+ *
+ * @av_buf_head - circular buffer head
+ * @av_buf_tail - circular buffer tail
+ * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the
+ * buffer (i.e. %av_buf_head)
+ * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
+ * by the buffer with State 0
*
- * This implements a fixed-size circular buffer within an array and is largely
- * based on Appendix A of RFC 4340.
+ * Additionally, the HC-Receiver must keep some information about the
+ * Ack Vectors it has recently sent. For each packet sent carrying an
+ * Ack Vector, it remembers four variables:
*
- * @av_buf: circular buffer storage area
- * @av_buf_head: head index; begin of live portion in @av_buf
- * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf
- * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf
- * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf
- * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to
- * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
- * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
- * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
- * @av_veclen: length of the live portion of @av_buf
+ * @av_records - list of dccp_ackvec_record
+ * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
+ *
+ * @av_time - the time in usecs
+ * @av_buf - circular buffer of acknowledgeable packets
*/
struct dccp_ackvec {
- u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
- u16 av_buf_head;
- u16 av_buf_tail;
- u64 av_buf_ackno:48;
- u64 av_tail_ackno:48;
- bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
- u8 av_overflow:1;
+ u64 av_buf_ackno;
struct list_head av_records;
+ ktime_t av_time;
+ u16 av_buf_head;
u16 av_vec_len;
+ u8 av_buf_nonce;
+ u8 av_ack_nonce;
+ u8 av_buf[DCCP_MAX_ACKVEC_LEN];
};
-/** struct dccp_ackvec_record - Records information about sent Ack Vectors
+/** struct dccp_ackvec_record - ack vector record
*
- * These list entries define the additional information which the HC-Receiver
- * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A.
+ * ACK vector record as defined in Appendix A of spec.
*
- * @avr_node: the list node in @av_records
- * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on
- * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to
- * @avr_ack_ptr: pointer into @av_buf where this record starts
- * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending
- * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent
+ * The list is sorted by avr_ack_seqno
*
- * The list as a whole is sorted in descending order by @avr_ack_seqno.
+ * @avr_node - node in av_records
+ * @avr_ack_seqno - sequence number of the packet this record was sent on
+ * @avr_ack_ackno - sequence number being acknowledged
+ * @avr_ack_ptr - pointer into av_buf where this record starts
+ * @avr_ack_nonce - av_ack_nonce at the time this record was sent
+ * @avr_sent_len - lenght of the record in av_buf
*/
struct dccp_ackvec_record {
struct list_head avr_node;
- u64 avr_ack_seqno:48;
- u64 avr_ack_ackno:48;
+ u64 avr_ack_seqno;
+ u64 avr_ack_ackno;
u16 avr_ack_ptr;
- u8 avr_ack_runlen;
- u8 avr_ack_nonce:1;
+ u16 avr_sent_len;
+ u8 avr_ack_nonce;
};
struct sock;
struct sk_buff;
-#ifdef CONFIG_IP_DCCP_ACKVEC
extern int dccp_ackvec_init(void);
extern void dccp_ackvec_exit(void);
u64 *ackno, const u8 opt,
const u8 *value, const u8 len);
-extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
-extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
-extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
-
-static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
-{
- return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
-}
-#else /* CONFIG_IP_DCCP_ACKVEC */
-static inline int dccp_ackvec_init(void)
-{
- return 0;
-}
-
-static inline void dccp_ackvec_exit(void)
-{
-}
-
-static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
-{
- return NULL;
-}
-
-static inline void dccp_ackvec_free(struct dccp_ackvec *av)
-{
-}
-
-static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
- const u64 ackno, const u8 state)
-{
- return -1;
-}
-
-static inline void dccp_ackvec_clear_state(struct dccp_ackvec *av,
- const u64 ackno)
-{
-}
-
-static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
- struct sock *sk, const u64 ackno)
-{
-}
-
-static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
- const u64 *ackno, const u8 opt,
- const u8 *value, const u8 len)
-{
- return -1;
-}
-
-static inline int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 nonce)
-{
- return -1;
-}
-
-static inline u16 dccp_ackvec_buflen(const struct dccp_ackvec *av)
-{
- return 0;
-}
+extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
-static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
+static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
{
- return true;
+ return av->av_vec_len;
}
-#endif /* CONFIG_IP_DCCP_ACKVEC */
#endif /* _ACKVEC_H */
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