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