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/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_seqno - the Sequence Number used for the packet
  46  *                     (HC-Receiver seqno)
  47  * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
  48  * @dccpav_ack_ackno - the Acknowledgement Number used for the packet
  49  *                     (HC-Sender seqno)
  50  * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
  51  *
  52  * @dccpav_time         - the time in usecs
  53  * @dccpav_buf - circular buffer of acknowledgeable packets
  54  */
  55 struct dccp_ackvec {
  56         u64             dccpav_buf_ackno;
  57         u64             dccpav_ack_seqno;
  58         u64             dccpav_ack_ackno;
  59         struct timeval  dccpav_time;
  60         u8              dccpav_buf_head;
  61         u8              dccpav_buf_tail;
  62         u8              dccpav_ack_ptr;
  63         u8              dccpav_sent_len;
  64         u8              dccpav_vec_len;
  65         u8              dccpav_buf_nonce;
  66         u8              dccpav_ack_nonce;
  67         u8              dccpav_buf[DCCP_MAX_ACKVEC_LEN];
  68 };
  69
  70 struct sock;
  71 struct sk_buff;
  72
  73 #ifdef CONFIG_IP_DCCP_ACKVEC
  74 extern int dccp_ackvec_init(void);
  75 extern void dccp_ackvec_exit(void);
  76
  77 extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
  78 extern void dccp_ackvec_free(struct dccp_ackvec *av);
  79
  80 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
  81                            const u64 ackno, const u8 state);
  82
  83 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
  84                                         struct sock *sk, const u64 ackno);
  85 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
  86                              const u8 opt, const u8 *value, const u8 len);
  87
  88 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
  89
  90 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
  91 {
  92         return av->dccpav_sent_len != av->dccpav_vec_len;
  93 }
  94 #else /* CONFIG_IP_DCCP_ACKVEC */
  95 static inline int dccp_ackvec_init(void)
  96 {
  97         return 0;
  98 }
  99
 100 static inline void dccp_ackvec_exit(void)
 101 {
 102 }
 103
 104 static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
 105 {
 106         return NULL;
 107 }
 108
 109 static inline void dccp_ackvec_free(struct dccp_ackvec *av)
 110 {
 111 }
 112
 113 static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
 114                                   const u64 ackno, const u8 state)
 115 {
 116         return -1;
 117 }
 118
 119 static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
 120                                                struct sock *sk, const u64 ackno)
 121 {
 122 }
 123
 124 static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
 125                                     const u8 opt, const u8 *value, const u8 len)
 126 {
 127         return -1;
 128 }
 129
 130 static inline int dccp_insert_option_ackvec(const struct sock *sk,
 131                                             const struct sk_buff *skb)
 132 {
 133         return -1;
 134 }
 135
 136 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
 137 {
 138         return 0;
 139 }
 140 #endif /* CONFIG_IP_DCCP_ACKVEC */
 141 #endif /* _ACKVEC_H */