net/dccp/ackvec.h

   1 #ifndef _ACKVEC_H
   2 #define _ACKVEC_H
   3 /*
   4  *  net/dccp/ackvec.h
   5  *
   6  *  An implementation of the DCCP protocol
   7  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License version 2 as
  11  *      published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/compiler.h>
  15 #include <linux/list.h>
  16 #include <linux/time.h>
  17 #include <linux/types.h>
  18
  19 /* Read about the ECN nonce to see why it is 253 */
  20 #define DCCP_MAX_ACKVEC_LEN 253
  21
  22 #define DCCP_ACKVEC_STATE_RECEIVED      0
  23 #define DCCP_ACKVEC_STATE_ECN_MARKED    (1 << 6)
  24 #define DCCP_ACKVEC_STATE_NOT_RECEIVED  (3 << 6)
  25
  26 #define DCCP_ACKVEC_STATE_MASK          0xC0 /* 11000000 */
  27 #define DCCP_ACKVEC_LEN_MASK            0x3F /* 00111111 */
  28
  29 /** struct dccp_ackvec - ack vector
  30  *
  31  * This data structure is the one defined in the DCCP draft
  32  * Appendix A.
  33  *
  34  * @dccpav_buf_head - circular buffer head
  35  * @dccpav_buf_tail - circular buffer tail
  36  * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
  37  *                     buffer (i.e. %dccpav_buf_head)
  38  * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
  39  *                     by the buffer with State 0
  40  *
  41  * Additionally, the HC-Receiver must keep some information about the
  42  * Ack Vectors it has recently sent. For each packet sent carrying an
  43  * Ack Vector, it remembers four variables:
  44  *
  45  * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
  46  * @dccpav_records - list of dccp_ackvec_record
  47  * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
  48  *
  49  * @dccpav_time         - the time in usecs
  50  * @dccpav_buf - circular buffer of acknowledgeable packets
  51  */
  52 struct dccp_ackvec {
  53         u64             dccpav_buf_ackno;
  54         struct list_head dccpav_records;
  55         struct timeval  dccpav_time;
  56         u8              dccpav_buf_head;
  57         u8              dccpav_buf_tail;
  58         u8              dccpav_ack_ptr;
  59         u8              dccpav_sent_len;
  60         u8              dccpav_vec_len;
  61         u8              dccpav_buf_nonce;
  62         u8              dccpav_ack_nonce;
  63         u8              dccpav_buf[DCCP_MAX_ACKVEC_LEN];
  64 };
  65
  66 /** struct dccp_ackvec_record - ack vector record
  67  *
  68  * ACK vector record as defined in Appendix A of spec.
  69  *
  70  * The list is sorted by dccpavr_ack_seqno
  71  *
  72  * @dccpavr_node - node in dccpav_records
  73  * @dccpavr_ack_seqno - sequence number of the packet this record was sent on
  74  * @dccpavr_ack_ackno - sequence number being acknowledged
  75  * @dccpavr_ack_ptr - pointer into dccpav_buf where this record starts
  76  * @dccpavr_ack_nonce - dccpav_ack_nonce at the time this record was sent
  77  * @dccpavr_sent_len - lenght of the record in dccpav_buf
  78  */
  79 struct dccp_ackvec_record {
  80         struct list_head dccpavr_node;
  81         u64              dccpavr_ack_seqno;
  82         u64              dccpavr_ack_ackno;
  83         u8               dccpavr_ack_ptr;
  84         u8               dccpavr_ack_nonce;
  85         u8               dccpavr_sent_len;
  86 };
  87
  88 struct sock;
  89 struct sk_buff;
  90
  91 #ifdef CONFIG_IP_DCCP_ACKVEC
  92 extern int dccp_ackvec_init(void);
  93 extern void dccp_ackvec_exit(void);
  94
  95 extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
  96 extern void dccp_ackvec_free(struct dccp_ackvec *av);
  97
  98 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
  99                            const u64 ackno, const u8 state);
 100
 101 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
 102                                         struct sock *sk, const u64 ackno);
 103 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 104                              const u8 opt, const u8 *value, const u8 len);
 105
 106 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
 107
 108 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 109 {
 110         return av->dccpav_sent_len != av->dccpav_vec_len;
 111 }
 112 #else /* CONFIG_IP_DCCP_ACKVEC */
 113 static inline int dccp_ackvec_init(void)
 114 {
 115         return 0;
 116 }
 117
 118 static inline void dccp_ackvec_exit(void)
 119 {
 120 }
 121
 122 static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
 123 {
 124         return NULL;
 125 }
 126
 127 static inline void dccp_ackvec_free(struct dccp_ackvec *av)
 128 {
 129 }
 130
 131 static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
 132                                   const u64 ackno, const u8 state)
 133 {
 134         return -1;
 135 }
 136
 137 static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
 138                                                struct sock *sk, const u64 ackno)
 139 {
 140 }
 141
 142 static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 143                                     const u8 opt, const u8 *value, const u8 len)
 144 {
 145         return -1;
 146 }
 147
 148 static inline int dccp_insert_option_ackvec(const struct sock *sk,
 149                                             const struct sk_buff *skb)
 150 {
 151         return -1;
 152 }
 153
 154 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 155 {
 156         return 0;
 157 }
 158 #endif /* CONFIG_IP_DCCP_ACKVEC */
 159 #endif /* _ACKVEC_H */