cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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packet_history.h (4469B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 *  Packet RX/TX history data structures and routines for TFRC-based protocols.
      4 *
      5 *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
      6 *  Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
      7 *
      8 *  This code has been developed by the University of Waikato WAND
      9 *  research group. For further information please see https://www.wand.net.nz/
     10 *  or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz
     11 *
     12 *  This code also uses code from Lulea University, rereleased as GPL by its
     13 *  authors:
     14 *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
     15 *
     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>.
     19 *
     20 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
     21 */
     22
     23#ifndef _DCCP_PKT_HIST_
     24#define _DCCP_PKT_HIST_
     25
     26#include <linux/list.h>
     27#include <linux/slab.h>
     28#include "tfrc.h"
     29
     30/**
     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
     35 */
     36struct tfrc_tx_hist_entry {
     37	struct tfrc_tx_hist_entry *next;
     38	u64			  seqno;
     39	ktime_t			  stamp;
     40};
     41
     42static inline struct tfrc_tx_hist_entry *
     43	tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
     44{
     45	while (head != NULL && head->seqno != seqno)
     46		head = head->next;
     47	return head;
     48}
     49
     50int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
     51void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
     52
     53/* Subtraction a-b modulo-16, respects circular wrap-around */
     54#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
     55
     56/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
     57#define TFRC_NDUPACK 3
     58
     59/**
     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
     65 */
     66struct tfrc_rx_hist_entry {
     67	u64		 tfrchrx_seqno:48,
     68			 tfrchrx_ccval:4,
     69			 tfrchrx_type:4;
     70	u64		 tfrchrx_ndp:48;
     71	ktime_t		 tfrchrx_tstamp;
     72};
     73
     74/**
     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
     80 */
     81struct tfrc_rx_hist {
     82	struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
     83	u8			  loss_count:2,
     84				  loss_start:2;
     85#define rtt_sample_prev		  loss_start
     86};
     87
     88/**
     89 * tfrc_rx_hist_index - index to reach n-th entry after loss_start
     90 */
     91static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n)
     92{
     93	return (h->loss_start + n) & TFRC_NDUPACK;
     94}
     95
     96/**
     97 * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
     98 */
     99static inline struct tfrc_rx_hist_entry *
    100			tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h)
    101{
    102	return h->ring[tfrc_rx_hist_index(h, h->loss_count)];
    103}
    104
    105/**
    106 * tfrc_rx_hist_entry - return the n-th history entry after loss_start
    107 */
    108static inline struct tfrc_rx_hist_entry *
    109			tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n)
    110{
    111	return h->ring[tfrc_rx_hist_index(h, n)];
    112}
    113
    114/**
    115 * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
    116 */
    117static inline struct tfrc_rx_hist_entry *
    118			tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h)
    119{
    120	return h->ring[h->loss_start];
    121}
    122
    123/* indicate whether previously a packet was detected missing */
    124static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
    125{
    126	return h->loss_count > 0;
    127}
    128
    129void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, const struct sk_buff *skb,
    130			     const u64 ndp);
    131
    132int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
    133
    134struct tfrc_loss_hist;
    135int 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);
    138u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb);
    139int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
    140void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
    141
    142#endif /* _DCCP_PKT_HIST_ */