1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Packet RX/TX history data structures and routines for TFRC-based protocols.
5 * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
6 * Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
8 * This code has been developed by the University of Waikato WAND
9 * research group. For further information please see http://www.wand.net.nz/
10 * or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
12 * This code also uses code from Lulea University, rereleased as GPL by its
14 * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
16 * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17 * and to make it work as a loadable module in the DCCP stack written by
18 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
20 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
23 #ifndef _DCCP_PKT_HIST_
24 #define _DCCP_PKT_HIST_
26 #include <linux/list.h>
27 #include <linux/slab.h>
31 * tfrc_tx_hist_entry - Simple singly-linked TX history list
32 * @next: next oldest entry (LIFO order)
33 * @seqno: sequence number of this entry
34 * @stamp: send time of packet with sequence number @seqno
36 struct tfrc_tx_hist_entry
{
37 struct tfrc_tx_hist_entry
*next
;
42 static inline struct tfrc_tx_hist_entry
*
43 tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry
*head
, u64 seqno
)
45 while (head
!= NULL
&& head
->seqno
!= seqno
)
50 int tfrc_tx_hist_add(struct tfrc_tx_hist_entry
**headp
, u64 seqno
);
51 void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry
**headp
);
53 /* Subtraction a-b modulo-16, respects circular wrap-around */
54 #define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
56 /* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
57 #define TFRC_NDUPACK 3
60 * tfrc_rx_hist_entry - Store information about a single received packet
61 * @tfrchrx_seqno: DCCP packet sequence number
62 * @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1)
63 * @tfrchrx_ndp: the NDP count (if any) of the packet
64 * @tfrchrx_tstamp: actual receive time of packet
66 struct tfrc_rx_hist_entry
{
71 ktime_t tfrchrx_tstamp
;
75 * tfrc_rx_hist - RX history structure for TFRC-based protocols
76 * @ring: Packet history for RTT sampling and loss detection
77 * @loss_count: Number of entries in circular history
78 * @loss_start: Movable index (for loss detection)
79 * @rtt_sample_prev: Used during RTT sampling, points to candidate entry
82 struct tfrc_rx_hist_entry
*ring
[TFRC_NDUPACK
+ 1];
85 #define rtt_sample_prev loss_start
89 * tfrc_rx_hist_index - index to reach n-th entry after loss_start
91 static inline u8
tfrc_rx_hist_index(const struct tfrc_rx_hist
*h
, const u8 n
)
93 return (h
->loss_start
+ n
) & TFRC_NDUPACK
;
97 * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
99 static inline struct tfrc_rx_hist_entry
*
100 tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist
*h
)
102 return h
->ring
[tfrc_rx_hist_index(h
, h
->loss_count
)];
106 * tfrc_rx_hist_entry - return the n-th history entry after loss_start
108 static inline struct tfrc_rx_hist_entry
*
109 tfrc_rx_hist_entry(const struct tfrc_rx_hist
*h
, const u8 n
)
111 return h
->ring
[tfrc_rx_hist_index(h
, n
)];
115 * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
117 static inline struct tfrc_rx_hist_entry
*
118 tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist
*h
)
120 return h
->ring
[h
->loss_start
];
123 /* indicate whether previously a packet was detected missing */
124 static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist
*h
)
126 return h
->loss_count
> 0;
129 void tfrc_rx_hist_add_packet(struct tfrc_rx_hist
*h
, const struct sk_buff
*skb
,
132 int tfrc_rx_hist_duplicate(struct tfrc_rx_hist
*h
, struct sk_buff
*skb
);
134 struct tfrc_loss_hist
;
135 int tfrc_rx_handle_loss(struct tfrc_rx_hist
*h
, struct tfrc_loss_hist
*lh
,
136 struct sk_buff
*skb
, const u64 ndp
,
137 u32 (*first_li
)(struct sock
*sk
), struct sock
*sk
);
138 u32
tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist
*h
, const struct sk_buff
*skb
);
139 int tfrc_rx_hist_alloc(struct tfrc_rx_hist
*h
);
140 void tfrc_rx_hist_purge(struct tfrc_rx_hist
*h
);
142 #endif /* _DCCP_PKT_HIST_ */