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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x25_timer.c (3667B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *	X.25 Packet Layer release 002
      4 *
      5 *	This is ALPHA test software. This code may break your machine,
      6 *	randomly fail to work with new releases, misbehave and/or generally
      7 *	screw up. It might even work.
      8 *
      9 *	This code REQUIRES 2.1.15 or higher
     10 *
     11 *	History
     12 *	X.25 001	Jonathan Naylor	Started coding.
     13 *	X.25 002	Jonathan Naylor	New timer architecture.
     14 *					Centralised disconnection processing.
     15 */
     16
     17#include <linux/errno.h>
     18#include <linux/jiffies.h>
     19#include <linux/timer.h>
     20#include <net/sock.h>
     21#include <net/tcp_states.h>
     22#include <net/x25.h>
     23
     24static void x25_heartbeat_expiry(struct timer_list *t);
     25static void x25_timer_expiry(struct timer_list *t);
     26
     27void x25_init_timers(struct sock *sk)
     28{
     29	struct x25_sock *x25 = x25_sk(sk);
     30
     31	timer_setup(&x25->timer, x25_timer_expiry, 0);
     32
     33	/* initialized by sock_init_data */
     34	sk->sk_timer.function = x25_heartbeat_expiry;
     35}
     36
     37void x25_start_heartbeat(struct sock *sk)
     38{
     39	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
     40}
     41
     42void x25_stop_heartbeat(struct sock *sk)
     43{
     44	del_timer(&sk->sk_timer);
     45}
     46
     47void x25_start_t2timer(struct sock *sk)
     48{
     49	struct x25_sock *x25 = x25_sk(sk);
     50
     51	mod_timer(&x25->timer, jiffies + x25->t2);
     52}
     53
     54void x25_start_t21timer(struct sock *sk)
     55{
     56	struct x25_sock *x25 = x25_sk(sk);
     57
     58	mod_timer(&x25->timer, jiffies + x25->t21);
     59}
     60
     61void x25_start_t22timer(struct sock *sk)
     62{
     63	struct x25_sock *x25 = x25_sk(sk);
     64
     65	mod_timer(&x25->timer, jiffies + x25->t22);
     66}
     67
     68void x25_start_t23timer(struct sock *sk)
     69{
     70	struct x25_sock *x25 = x25_sk(sk);
     71
     72	mod_timer(&x25->timer, jiffies + x25->t23);
     73}
     74
     75void x25_stop_timer(struct sock *sk)
     76{
     77	del_timer(&x25_sk(sk)->timer);
     78}
     79
     80unsigned long x25_display_timer(struct sock *sk)
     81{
     82	struct x25_sock *x25 = x25_sk(sk);
     83
     84	if (!timer_pending(&x25->timer))
     85		return 0;
     86
     87	return x25->timer.expires - jiffies;
     88}
     89
     90static void x25_heartbeat_expiry(struct timer_list *t)
     91{
     92	struct sock *sk = from_timer(sk, t, sk_timer);
     93
     94	bh_lock_sock(sk);
     95	if (sock_owned_by_user(sk)) /* can currently only occur in state 3 */
     96		goto restart_heartbeat;
     97
     98	switch (x25_sk(sk)->state) {
     99
    100		case X25_STATE_0:
    101			/*
    102			 * Magic here: If we listen() and a new link dies
    103			 * before it is accepted() it isn't 'dead' so doesn't
    104			 * get removed.
    105			 */
    106			if (sock_flag(sk, SOCK_DESTROY) ||
    107			    (sk->sk_state == TCP_LISTEN &&
    108			     sock_flag(sk, SOCK_DEAD))) {
    109				bh_unlock_sock(sk);
    110				x25_destroy_socket_from_timer(sk);
    111				return;
    112			}
    113			break;
    114
    115		case X25_STATE_3:
    116			/*
    117			 * Check for the state of the receive buffer.
    118			 */
    119			x25_check_rbuf(sk);
    120			break;
    121	}
    122restart_heartbeat:
    123	x25_start_heartbeat(sk);
    124	bh_unlock_sock(sk);
    125}
    126
    127/*
    128 *	Timer has expired, it may have been T2, T21, T22, or T23. We can tell
    129 *	by the state machine state.
    130 */
    131static inline void x25_do_timer_expiry(struct sock * sk)
    132{
    133	struct x25_sock *x25 = x25_sk(sk);
    134
    135	switch (x25->state) {
    136
    137		case X25_STATE_3:	/* T2 */
    138			if (x25->condition & X25_COND_ACK_PENDING) {
    139				x25->condition &= ~X25_COND_ACK_PENDING;
    140				x25_enquiry_response(sk);
    141			}
    142			break;
    143
    144		case X25_STATE_1:	/* T21 */
    145		case X25_STATE_4:	/* T22 */
    146			x25_write_internal(sk, X25_CLEAR_REQUEST);
    147			x25->state = X25_STATE_2;
    148			x25_start_t23timer(sk);
    149			break;
    150
    151		case X25_STATE_2:	/* T23 */
    152			x25_disconnect(sk, ETIMEDOUT, 0, 0);
    153			break;
    154	}
    155}
    156
    157static void x25_timer_expiry(struct timer_list *t)
    158{
    159	struct x25_sock *x25 = from_timer(x25, t, timer);
    160	struct sock *sk = &x25->sk;
    161
    162	bh_lock_sock(sk);
    163	if (sock_owned_by_user(sk)) { /* can currently only occur in state 3 */
    164		if (x25_sk(sk)->state == X25_STATE_3)
    165			x25_start_t2timer(sk);
    166	} else
    167		x25_do_timer_expiry(sk);
    168	bh_unlock_sock(sk);
    169}