| #ifndef _ACKVEC_H |
| #define _ACKVEC_H |
| /* |
| * net/dccp/ackvec.h |
| * |
| * 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/dccp.h> |
| #include <linux/compiler.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 |
| |
| 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 main data structure |
| * |
| * This implements a fixed-size circular buffer within an array and is largely |
| * based on Appendix A of RFC 4340. |
| * |
| * @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 |
| * |
| * These list entries define the additional information which the HC-Receiver |
| * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. |
| * |
| * @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 as a whole is sorted in descending order by @avr_ack_seqno. |
| */ |
| 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; |
| }; |
| |
| int dccp_ackvec_init(void); |
| void dccp_ackvec_exit(void); |
| |
| struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); |
| void dccp_ackvec_free(struct dccp_ackvec *av); |
| |
| 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 bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) |
| { |
| return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; |
| } |
| |
| /** |
| * 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; |
| }; |
| |
| 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 */ |