diff options
Diffstat (limited to 'net/dccp/ackvec.h')
| -rw-r--r-- | net/dccp/ackvec.h | 205 |
1 files changed, 105 insertions, 100 deletions
diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h index d0fd6c60c57..3284bfa988c 100644 --- a/net/dccp/ackvec.h +++ b/net/dccp/ackvec.h @@ -3,131 +3,136 @@ /* * net/dccp/ackvec.h * - * An implementation of the DCCP protocol + * An implementation of Ack Vectors for the DCCP protocol + * Copyright (c) 2007 University of Aberdeen, Scotland, UK * 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/config.h> +#include <linux/dccp.h> #include <linux/compiler.h> -#include <linux/time.h> +#include <linux/list.h> #include <linux/types.h> -/* Read about the ECN nonce to see why it is 253 */ -#define DCCP_MAX_ACKVEC_LEN 253 +/* + * 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 + +/* Threshold for coping with large bursts of losses */ +#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8) -#define DCCP_ACKVEC_STATE_RECEIVED 0 -#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6) -#define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6) +enum dccp_ackvec_states { + DCCPAV_RECEIVED = 0x00, + DCCPAV_ECN_MARKED = 0x40, + DCCPAV_RESERVED = 0x80, + DCCPAV_NOT_RECEIVED = 0xC0 +}; +#define DCCPAV_MAX_RUNLEN 0x3F -#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */ -#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */ +static inline u8 dccp_ackvec_runlen(const u8 *cell) +{ + return *cell & DCCPAV_MAX_RUNLEN; +} + +static inline u8 dccp_ackvec_state(const u8 *cell) +{ + return *cell & ~DCCPAV_MAX_RUNLEN; +} -/** struct dccp_ackvec - ack vector +/** + * struct dccp_ackvec - Ack Vector main data structure * - * This data structure is the one defined in the DCCP draft - * Appendix A. + * This implements a fixed-size circular buffer within an array and is largely + * based on Appendix A of RFC 4340. * - * @dccpav_buf_head - circular buffer head - * @dccpav_buf_tail - circular buffer tail - * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the - * buffer (i.e. %dccpav_buf_head) - * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked - * by the buffer with State 0 + * @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) + */ +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; + struct list_head av_records; +}; + +/** + * struct dccp_ackvec_record - Records information about sent Ack Vectors * - * 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: + * These list entries define the additional information which the HC-Receiver + * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. * - * @dccpav_ack_seqno - the Sequence Number used for the packet - * (HC-Receiver seqno) - * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement. - * @dccpav_ack_ackno - the Acknowledgement Number used for the packet - * (HC-Sender seqno) - * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0. + * @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 * - * @dccpav_buf_len - circular buffer length - * @dccpav_time - the time in usecs - * @dccpav_buf - circular buffer of acknowledgeable packets + * The list as a whole is sorted in descending order by @avr_ack_seqno. */ -struct dccp_ackvec { - unsigned int dccpav_buf_head; - unsigned int dccpav_buf_tail; - u64 dccpav_buf_ackno; - u64 dccpav_ack_seqno; - u64 dccpav_ack_ackno; - unsigned int dccpav_ack_ptr; - unsigned int dccpav_sent_len; - unsigned int dccpav_vec_len; - unsigned int dccpav_buf_len; - struct timeval dccpav_time; - u8 dccpav_buf_nonce; - u8 dccpav_ack_nonce; - u8 dccpav_buf[0]; +struct dccp_ackvec_record { + struct list_head avr_node; + u64 avr_ack_seqno:48; + u64 avr_ack_ackno:48; + u16 avr_ack_ptr; + u8 avr_ack_runlen; + u8 avr_ack_nonce:1; }; -struct sock; -struct sk_buff; - -#ifdef CONFIG_IP_DCCP_ACKVEC -extern struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len, - const gfp_t priority); -extern void dccp_ackvec_free(struct dccp_ackvec *av); - -extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, - const u64 ackno, const u8 state); +int dccp_ackvec_init(void); +void dccp_ackvec_exit(void); -extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, - struct sock *sk, const u64 ackno); -extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, - const u8 opt, const u8 *value, const u8 len); +struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); +void dccp_ackvec_free(struct dccp_ackvec *av); -extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); +void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb); +int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum); +void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno); +u16 dccp_ackvec_buflen(const struct dccp_ackvec *av); -static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) -{ - return av->dccpav_sent_len != av->dccpav_vec_len; -} -#else /* CONFIG_IP_DCCP_ACKVEC */ -static inline struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len, - const gfp_t priority) +static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) { - return NULL; + return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; } -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_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 u8 opt, const u8 *value, const u8 len) -{ - return -1; -} - -static inline int dccp_insert_option_ackvec(const struct sock *sk, - const struct sk_buff *skb) -{ - return -1; -} +/** + * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb + * @vec: start of vector (offset into skb) + * @len: length of @vec + * @nonce: whether @vec had an ECN nonce of 0 or 1 + * @node: FIFO - arranged in descending order of ack_ackno + * + * This structure is used by CCIDs to access Ack Vectors in a received skb. + */ +struct dccp_ackvec_parsed { + u8 *vec, + len, + nonce:1; + struct list_head node; +}; -static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) -{ - return 0; -} -#endif /* CONFIG_IP_DCCP_ACKVEC */ +int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce); +void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks); #endif /* _ACKVEC_H */ |