1*d2912cb1SThomas Gleixner /* SPDX-License-Identifier: GPL-2.0-only */ 2ae31c339SArnaldo Carvalho de Melo #ifndef _ACKVEC_H 3ae31c339SArnaldo Carvalho de Melo #define _ACKVEC_H 4ae31c339SArnaldo Carvalho de Melo /* 5ae31c339SArnaldo Carvalho de Melo * net/dccp/ackvec.h 6ae31c339SArnaldo Carvalho de Melo * 7f17a37c9SGerrit Renker * An implementation of Ack Vectors for the DCCP protocol 8f17a37c9SGerrit Renker * Copyright (c) 2007 University of Aberdeen, Scotland, UK 9ae31c339SArnaldo Carvalho de Melo * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com> 10ae31c339SArnaldo Carvalho de Melo */ 11ae31c339SArnaldo Carvalho de Melo 12b20a9c24SGerrit Renker #include <linux/dccp.h> 13ae31c339SArnaldo Carvalho de Melo #include <linux/compiler.h> 1402bcf28cSAndrea Bittau #include <linux/list.h> 15ae31c339SArnaldo Carvalho de Melo #include <linux/types.h> 16ae31c339SArnaldo Carvalho de Melo 17f17a37c9SGerrit Renker /* 18f17a37c9SGerrit Renker * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN, 19f17a37c9SGerrit Renker * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1 20f17a37c9SGerrit Renker * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives 21f17a37c9SGerrit Renker * more headroom if Ack Ratio is higher or when the sender acknowledges slowly. 22b3d14bffSGerrit Renker * The maximum value is bounded by the u16 types for indices and functions. 23f17a37c9SGerrit Renker */ 24f17a37c9SGerrit Renker #define DCCPAV_NUM_ACKVECS 2 25f17a37c9SGerrit Renker #define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS) 26ae31c339SArnaldo Carvalho de Melo 27361a5c1dSGerrit Renker /* Estimated minimum average Ack Vector length - used for updating MPS */ 28361a5c1dSGerrit Renker #define DCCPAV_MIN_OPTLEN 16 29361a5c1dSGerrit Renker 3038024086SGerrit Renker /* Threshold for coping with large bursts of losses */ 3138024086SGerrit Renker #define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8) 3238024086SGerrit Renker 33f17a37c9SGerrit Renker enum dccp_ackvec_states { 34f17a37c9SGerrit Renker DCCPAV_RECEIVED = 0x00, 35f17a37c9SGerrit Renker DCCPAV_ECN_MARKED = 0x40, 36f17a37c9SGerrit Renker DCCPAV_RESERVED = 0x80, 37f17a37c9SGerrit Renker DCCPAV_NOT_RECEIVED = 0xC0 38f17a37c9SGerrit Renker }; 39f17a37c9SGerrit Renker #define DCCPAV_MAX_RUNLEN 0x3F 40ae31c339SArnaldo Carvalho de Melo 41f17a37c9SGerrit Renker static inline u8 dccp_ackvec_runlen(const u8 *cell) 42f17a37c9SGerrit Renker { 43f17a37c9SGerrit Renker return *cell & DCCPAV_MAX_RUNLEN; 44f17a37c9SGerrit Renker } 45ae31c339SArnaldo Carvalho de Melo 46f17a37c9SGerrit Renker static inline u8 dccp_ackvec_state(const u8 *cell) 47f17a37c9SGerrit Renker { 48f17a37c9SGerrit Renker return *cell & ~DCCPAV_MAX_RUNLEN; 49f17a37c9SGerrit Renker } 50f17a37c9SGerrit Renker 512c53040fSBen Hutchings /** 522c53040fSBen Hutchings * struct dccp_ackvec - Ack Vector main data structure 53ae31c339SArnaldo Carvalho de Melo * 54f17a37c9SGerrit Renker * This implements a fixed-size circular buffer within an array and is largely 55f17a37c9SGerrit Renker * based on Appendix A of RFC 4340. 56ae31c339SArnaldo Carvalho de Melo * 57f17a37c9SGerrit Renker * @av_buf: circular buffer storage area 58f17a37c9SGerrit Renker * @av_buf_head: head index; begin of live portion in @av_buf 59f17a37c9SGerrit Renker * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf 60f17a37c9SGerrit Renker * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf 61b3d14bffSGerrit Renker * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf 62f17a37c9SGerrit Renker * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to 63f17a37c9SGerrit Renker * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf 64b3d14bffSGerrit Renker * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound 65f17a37c9SGerrit Renker * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously) 66ae31c339SArnaldo Carvalho de Melo */ 67ae31c339SArnaldo Carvalho de Melo struct dccp_ackvec { 68f17a37c9SGerrit Renker u8 av_buf[DCCPAV_MAX_ACKVEC_LEN]; 69a47c5104SGerrit Renker u16 av_buf_head; 70f17a37c9SGerrit Renker u16 av_buf_tail; 71f17a37c9SGerrit Renker u64 av_buf_ackno:48; 72b3d14bffSGerrit Renker u64 av_tail_ackno:48; 73f17a37c9SGerrit Renker bool av_buf_nonce[DCCPAV_NUM_ACKVECS]; 74b3d14bffSGerrit Renker u8 av_overflow:1; 75f17a37c9SGerrit Renker struct list_head av_records; 76ae31c339SArnaldo Carvalho de Melo }; 77ae31c339SArnaldo Carvalho de Melo 782c53040fSBen Hutchings /** 792c53040fSBen Hutchings * struct dccp_ackvec_record - Records information about sent Ack Vectors 8002bcf28cSAndrea Bittau * 81f17a37c9SGerrit Renker * These list entries define the additional information which the HC-Receiver 82f17a37c9SGerrit Renker * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. 8302bcf28cSAndrea Bittau * 84f17a37c9SGerrit Renker * @avr_node: the list node in @av_records 85f17a37c9SGerrit Renker * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on 86f17a37c9SGerrit Renker * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to 87f17a37c9SGerrit Renker * @avr_ack_ptr: pointer into @av_buf where this record starts 88f17a37c9SGerrit Renker * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending 89f17a37c9SGerrit Renker * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent 9002bcf28cSAndrea Bittau * 91f17a37c9SGerrit Renker * The list as a whole is sorted in descending order by @avr_ack_seqno. 9202bcf28cSAndrea Bittau */ 9302bcf28cSAndrea Bittau struct dccp_ackvec_record { 94a47c5104SGerrit Renker struct list_head avr_node; 95f17a37c9SGerrit Renker u64 avr_ack_seqno:48; 96f17a37c9SGerrit Renker u64 avr_ack_ackno:48; 97a47c5104SGerrit Renker u16 avr_ack_ptr; 98f17a37c9SGerrit Renker u8 avr_ack_runlen; 99f17a37c9SGerrit Renker u8 avr_ack_nonce:1; 10002bcf28cSAndrea Bittau }; 10102bcf28cSAndrea Bittau 102a402a5aaSJoe Perches int dccp_ackvec_init(void); 103a402a5aaSJoe Perches void dccp_ackvec_exit(void); 1049b07ef5dSArnaldo Carvalho de Melo 105a402a5aaSJoe Perches struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); 106a402a5aaSJoe Perches void dccp_ackvec_free(struct dccp_ackvec *av); 107ae31c339SArnaldo Carvalho de Melo 108a402a5aaSJoe Perches void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb); 109a402a5aaSJoe Perches int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum); 110a402a5aaSJoe Perches void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno); 111a402a5aaSJoe Perches u16 dccp_ackvec_buflen(const struct dccp_ackvec *av); 112ae31c339SArnaldo Carvalho de Melo 113b3d14bffSGerrit Renker static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) 114ae31c339SArnaldo Carvalho de Melo { 115b3d14bffSGerrit Renker return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; 116ae31c339SArnaldo Carvalho de Melo } 1177e87fe84SGerrit Renker 1187e87fe84SGerrit Renker /** 1197e87fe84SGerrit Renker * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb 1207e87fe84SGerrit Renker * @vec: start of vector (offset into skb) 1217e87fe84SGerrit Renker * @len: length of @vec 1227e87fe84SGerrit Renker * @nonce: whether @vec had an ECN nonce of 0 or 1 1237e87fe84SGerrit Renker * @node: FIFO - arranged in descending order of ack_ackno 1242c53040fSBen Hutchings * 1257e87fe84SGerrit Renker * This structure is used by CCIDs to access Ack Vectors in a received skb. 1267e87fe84SGerrit Renker */ 1277e87fe84SGerrit Renker struct dccp_ackvec_parsed { 1287e87fe84SGerrit Renker u8 *vec, 1297e87fe84SGerrit Renker len, 1307e87fe84SGerrit Renker nonce:1; 1317e87fe84SGerrit Renker struct list_head node; 1327e87fe84SGerrit Renker }; 1337e87fe84SGerrit Renker 134a402a5aaSJoe Perches int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce); 135a402a5aaSJoe Perches void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks); 136ae31c339SArnaldo Carvalho de Melo #endif /* _ACKVEC_H */ 137