diff options
Diffstat (limited to 'net/dccp/ackvec.h')
| -rw-r--r-- | net/dccp/ackvec.h | 204 |
1 files changed, 113 insertions, 91 deletions
diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h index 6cdca79..bcb64fb 100644 --- a/net/dccp/ackvec.h +++ b/net/dccp/ackvec.h @@ -3,134 +3,156 @@ /* * 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 - -/* Threshold for coping with large bursts of losses */ -#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8) - -enum dccp_ackvec_states { - DCCPAV_RECEIVED = 0x00, - DCCPAV_ECN_MARKED = 0x40, - DCCPAV_RESERVED = 0x80, - DCCPAV_NOT_RECEIVED = 0xC0 -}; -#define DCCPAV_MAX_RUNLEN 0x3F +/* Read about the ECN nonce to see why it is 253 */ +#define DCCP_MAX_ACKVEC_OPT_LEN 253 +/* We can spread an ack vector across multiple options */ +#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 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. * - * This implements a fixed-size circular buffer within an array and is largely - * based on Appendix A of RFC 4340. + * @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 * - * @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) + * 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_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; }; -extern int dccp_ackvec_init(void); +struct sock; +struct sk_buff; + +#ifdef CONFIG_IP_DCCP_ACKVEC +extern int dccp_ackvec_init(void); extern void dccp_ackvec_exit(void); extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); extern void dccp_ackvec_free(struct dccp_ackvec *av); -extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb); -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); +extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, + const u64 ackno, const u8 state); + +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, + u64 *ackno, const u8 opt, + const u8 *value, const u8 len); -static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) +extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); + +static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) +{ + return av->av_vec_len; +} +#else /* CONFIG_IP_DCCP_ACKVEC */ +static inline int dccp_ackvec_init(void) { - return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; + return 0; } -/** - * 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 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; +} -extern int dccp_ackvec_parsed_add(struct list_head *head, - u8 *vec, u8 len, u8 nonce); -extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks); +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_insert_option_ackvec(const struct sock *sk, + const struct sk_buff *skb) +{ + return -1; +} + +static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) +{ + return 0; +} +#endif /* CONFIG_IP_DCCP_ACKVEC */ #endif /* _ACKVEC_H */ |