/* SPDX-License-Identifier: GPL-2.0-only */ #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 <[email protected]> */ #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 … #define DCCPAV_MAX_ACKVEC_LEN … /* Estimated minimum average Ack Vector length - used for updating MPS */ #define DCCPAV_MIN_OPTLEN … /* Threshold for coping with large bursts of losses */ #define DCCPAV_BURST_THRESH … enum dccp_ackvec_states { … }; #define DCCPAV_MAX_RUNLEN … static inline u8 dccp_ackvec_runlen(const u8 *cell) { … } static inline u8 dccp_ackvec_state(const u8 *cell) { … } /** * 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 { … }; /** * 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 { … }; 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) { … } /** * 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 { … }; 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 */
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