diff options
Diffstat (limited to 'net/dccp/ccids/lib/packet_history.h')
| -rw-r--r-- | net/dccp/ccids/lib/packet_history.h | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h new file mode 100644 index 000000000..159cc9326 --- /dev/null +++ b/net/dccp/ccids/lib/packet_history.h @@ -0,0 +1,142 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Packet RX/TX history data structures and routines for TFRC-based protocols. + * + * Copyright (c) 2007 The University of Aberdeen, Scotland, UK + * Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand. + * + * This code has been developed by the University of Waikato WAND + * research group. For further information please see https://www.wand.net.nz/ + * or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz + * + * This code also uses code from Lulea University, rereleased as GPL by its + * authors: + * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon + * + * Changes to meet Linux coding standards, to make it meet latest ccid3 draft + * and to make it work as a loadable module in the DCCP stack written by + * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. + * + * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> + */ + +#ifndef _DCCP_PKT_HIST_ +#define _DCCP_PKT_HIST_ + +#include <linux/list.h> +#include <linux/slab.h> +#include "tfrc.h" + +/** + * tfrc_tx_hist_entry - Simple singly-linked TX history list + * @next: next oldest entry (LIFO order) + * @seqno: sequence number of this entry + * @stamp: send time of packet with sequence number @seqno + */ +struct tfrc_tx_hist_entry { + struct tfrc_tx_hist_entry *next; + u64 seqno; + ktime_t stamp; +}; + +static inline struct tfrc_tx_hist_entry * + tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno) +{ + while (head != NULL && head->seqno != seqno) + head = head->next; + return head; +} + +int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno); +void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp); + +/* Subtraction a-b modulo-16, respects circular wrap-around */ +#define SUB16(a, b) (((a) + 16 - (b)) & 0xF) + +/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */ +#define TFRC_NDUPACK 3 + +/** + * tfrc_rx_hist_entry - Store information about a single received packet + * @tfrchrx_seqno: DCCP packet sequence number + * @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1) + * @tfrchrx_ndp: the NDP count (if any) of the packet + * @tfrchrx_tstamp: actual receive time of packet + */ +struct tfrc_rx_hist_entry { + u64 tfrchrx_seqno:48, + tfrchrx_ccval:4, + tfrchrx_type:4; + u64 tfrchrx_ndp:48; + ktime_t tfrchrx_tstamp; +}; + +/** + * tfrc_rx_hist - RX history structure for TFRC-based protocols + * @ring: Packet history for RTT sampling and loss detection + * @loss_count: Number of entries in circular history + * @loss_start: Movable index (for loss detection) + * @rtt_sample_prev: Used during RTT sampling, points to candidate entry + */ +struct tfrc_rx_hist { + struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; + u8 loss_count:2, + loss_start:2; +#define rtt_sample_prev loss_start +}; + +/** + * tfrc_rx_hist_index - index to reach n-th entry after loss_start + */ +static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n) +{ + return (h->loss_start + n) & TFRC_NDUPACK; +} + +/** + * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far + */ +static inline struct tfrc_rx_hist_entry * + tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h) +{ + return h->ring[tfrc_rx_hist_index(h, h->loss_count)]; +} + +/** + * tfrc_rx_hist_entry - return the n-th history entry after loss_start + */ +static inline struct tfrc_rx_hist_entry * + tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n) +{ + return h->ring[tfrc_rx_hist_index(h, n)]; +} + +/** + * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected + */ +static inline struct tfrc_rx_hist_entry * + tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h) +{ + return h->ring[h->loss_start]; +} + +/* indicate whether previously a packet was detected missing */ +static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h) +{ + return h->loss_count > 0; +} + +void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb, + const u64 ndp); + +int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb); + +struct tfrc_loss_hist; +int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, struct tfrc_loss_hist *lh, + struct sk_buff *skb, const u64 ndp, + u32 (*first_li)(struct sock *sk), struct sock *sk); +u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb); +int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h); +void tfrc_rx_hist_purge(struct tfrc_rx_hist *h); + +#endif /* _DCCP_PKT_HIST_ */ |