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 RFC 4340, Appendix A.
  32  *
  33  * @dccpav_buf_head - circular buffer head
  34  * @dccpav_buf_tail - circular buffer tail
  35  * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
  36  *                     buffer (i.e. %dccpav_buf_head)
  37  * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
  38  *                     by the buffer with State 0
  39  *
  40  * Additionally, the HC-Receiver must keep some information about the
  41  * Ack Vectors it has recently sent. For each packet sent carrying an
  42  * Ack Vector, it remembers four variables:
  43  *
  44  * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
  45  * @dccpav_records - list of dccp_ackvec_record
  46  * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
  47  *
  48  * @dccpav_time         - the time in usecs
  49  * @dccpav_buf - circular buffer of acknowledgeable packets
  50  */
  51 struct dccp_ackvec {
  52         u64             dccpav_buf_ackno;
  53         struct list_head dccpav_records;
  54         struct timeval  dccpav_time;
  55         u8              dccpav_buf_head;
  56         u8              dccpav_ack_ptr;
  57         u8              dccpav_vec_len;
  58         u8              dccpav_buf_nonce;
  59         u8              dccpav_ack_nonce;
  60         u8              dccpav_buf[DCCP_MAX_ACKVEC_LEN];
  61 };
  62
  63 /** struct dccp_ackvec_record - ack vector record
  64  *
  65  * ACK vector record as defined in Appendix A of spec.
  66  *
  67  * The list is sorted by dccpavr_ack_seqno
  68  *
  69  * @dccpavr_node - node in dccpav_records
  70  * @dccpavr_ack_seqno - sequence number of the packet this record was sent on
  71  * @dccpavr_ack_ackno - sequence number being acknowledged
  72  * @dccpavr_ack_ptr - pointer into dccpav_buf where this record starts
  73  * @dccpavr_ack_nonce - dccpav_ack_nonce at the time this record was sent
  74  * @dccpavr_sent_len - lenght of the record in dccpav_buf
  75  */
  76 struct dccp_ackvec_record {
  77         struct list_head dccpavr_node;
  78         u64              dccpavr_ack_seqno;
  79         u64              dccpavr_ack_ackno;
  80         u8               dccpavr_ack_ptr;
  81         u8               dccpavr_ack_nonce;
  82         u8               dccpavr_sent_len;
  83 };
  84
  85 struct sock;
  86 struct sk_buff;
  87
  88 #ifdef CONFIG_IP_DCCP_ACKVEC
  89 extern int dccp_ackvec_init(void);
  90 extern void dccp_ackvec_exit(void);
  91
  92 extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
  93 extern void dccp_ackvec_free(struct dccp_ackvec *av);
  94
  95 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
  96                            const u64 ackno, const u8 state);
  97
  98 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
  99                                         struct sock *sk, const u64 ackno);
 100 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 101                              const u8 opt, const u8 *value, const u8 len);
 102
 103 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
 104
 105 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 106 {
 107         return av->dccpav_vec_len;
 108 }
 109 #else /* CONFIG_IP_DCCP_ACKVEC */
 110 static inline int dccp_ackvec_init(void)
 111 {
 112         return 0;
 113 }
 114
 115 static inline void dccp_ackvec_exit(void)
 116 {
 117 }
 118
 119 static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
 120 {
 121         return NULL;
 122 }
 123
 124 static inline void dccp_ackvec_free(struct dccp_ackvec *av)
 125 {
 126 }
 127
 128 static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
 129                                   const u64 ackno, const u8 state)
 130 {
 131         return -1;
 132 }
 133
 134 static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
 135                                                struct sock *sk, const u64 ackno)
 136 {
 137 }
 138
 139 static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 140                                     const u8 opt, const u8 *value, const u8 len)
 141 {
 142         return -1;
 143 }
 144
 145 static inline int dccp_insert_option_ackvec(const struct sock *sk,
 146                                             const struct sk_buff *skb)
 147 {
 148         return -1;
 149 }
 150
 151 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 152 {
 153         return 0;
 154 }
 155 #endif /* CONFIG_IP_DCCP_ACKVEC */
 156 #endif /* _ACKVEC_H */