[mirror_ubuntu-bionic-kernel.git] / net / rose / rose_in.c

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 *
 * Most of this code is based on the SDL diagrams published in the 7th ARRL
 * Computer Networking Conference papers. The diagrams have mistakes in them,
 * but are mostly correct. Before you modify the code could you read the SDL
 * diagrams as the code is not obvious and probably very easy to break.
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/rose.h>

/*
 * State machine for state 1, Awaiting Call Accepted State.
 * The handling of the timer(s) is in file rose_timer.c.
 * Handling of state 0 and connection release is in af_rose.c.
 */
static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct rose_sock *rose = rose_sk(sk);

	switch (frametype) {
	case ROSE_CALL_ACCEPTED:
		rose_stop_timer(sk);
		rose_start_idletimer(sk);
		rose->condition = 0x00;
		rose->vs        = 0;
		rose->va        = 0;
		rose->vr        = 0;
		rose->vl        = 0;
		rose->state     = ROSE_STATE_3;
		sk->sk_state	= TCP_ESTABLISHED;
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
		break;

	case ROSE_CLEAR_REQUEST:
		rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
		rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
		rose->neighbour->use--;
		break;

	default:
		break;
	}

	return 0;
}

/*
 * State machine for state 2, Awaiting Clear Confirmation State.
 * The handling of the timer(s) is in file rose_timer.c
 * Handling of state 0 and connection release is in af_rose.c.
 */
static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct rose_sock *rose = rose_sk(sk);

	switch (frametype) {
	case ROSE_CLEAR_REQUEST:
		rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
		rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
		rose->neighbour->use--;
		break;

	case ROSE_CLEAR_CONFIRMATION:
		rose_disconnect(sk, 0, -1, -1);
		rose->neighbour->use--;
		break;

	default:
		break;
	}

	return 0;
}

/*
 * State machine for state 3, Connected State.
 * The handling of the timer(s) is in file rose_timer.c
 * Handling of state 0 and connection release is in af_rose.c.
 */
static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
{
	struct rose_sock *rose = rose_sk(sk);
	int queued = 0;

	switch (frametype) {
	case ROSE_RESET_REQUEST:
		rose_stop_timer(sk);
		rose_start_idletimer(sk);
		rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
		rose->condition = 0x00;
		rose->vs        = 0;
		rose->vr        = 0;
		rose->va        = 0;
		rose->vl        = 0;
		rose_requeue_frames(sk);
		break;

	case ROSE_CLEAR_REQUEST:
		rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
		rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
		rose->neighbour->use--;
		break;

	case ROSE_RR:
	case ROSE_RNR:
		if (!rose_validate_nr(sk, nr)) {
			rose_write_internal(sk, ROSE_RESET_REQUEST);
			rose->condition = 0x00;
			rose->vs        = 0;
			rose->vr        = 0;
			rose->va        = 0;
			rose->vl        = 0;
			rose->state     = ROSE_STATE_4;
			rose_start_t2timer(sk);
			rose_stop_idletimer(sk);
		} else {
			rose_frames_acked(sk, nr);
			if (frametype == ROSE_RNR) {
				rose->condition |= ROSE_COND_PEER_RX_BUSY;
			} else {
				rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
			}
		}
		break;

	case ROSE_DATA:	/* XXX */
		rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
		if (!rose_validate_nr(sk, nr)) {
			rose_write_internal(sk, ROSE_RESET_REQUEST);
			rose->condition = 0x00;
			rose->vs        = 0;
			rose->vr        = 0;
			rose->va        = 0;
			rose->vl        = 0;
			rose->state     = ROSE_STATE_4;
			rose_start_t2timer(sk);
			rose_stop_idletimer(sk);
			break;
		}
		rose_frames_acked(sk, nr);
		if (ns == rose->vr) {
			rose_start_idletimer(sk);
			if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
			    __sock_queue_rcv_skb(sk, skb) == 0) {
				rose->vr = (rose->vr + 1) % ROSE_MODULUS;
				queued = 1;
			} else {
				/* Should never happen ! */
				rose_write_internal(sk, ROSE_RESET_REQUEST);
				rose->condition = 0x00;
				rose->vs        = 0;
				rose->vr        = 0;
				rose->va        = 0;
				rose->vl        = 0;
				rose->state     = ROSE_STATE_4;
				rose_start_t2timer(sk);
				rose_stop_idletimer(sk);
				break;
			}
			if (atomic_read(&sk->sk_rmem_alloc) >
			    (sk->sk_rcvbuf >> 1))
				rose->condition |= ROSE_COND_OWN_RX_BUSY;
		}
		/*
		 * If the window is full, ack the frame, else start the
		 * acknowledge hold back timer.
		 */
		if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
			rose->condition &= ~ROSE_COND_ACK_PENDING;
			rose_stop_timer(sk);
			rose_enquiry_response(sk);
		} else {
			rose->condition |= ROSE_COND_ACK_PENDING;
			rose_start_hbtimer(sk);
		}
		break;

	default:
		printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
		break;
	}

	return queued;
}

/*
 * State machine for state 4, Awaiting Reset Confirmation State.
 * The handling of the timer(s) is in file rose_timer.c
 * Handling of state 0 and connection release is in af_rose.c.
 */
static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct rose_sock *rose = rose_sk(sk);

	switch (frametype) {
	case ROSE_RESET_REQUEST:
		rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
		/* fall through */
	case ROSE_RESET_CONFIRMATION:
		rose_stop_timer(sk);
		rose_start_idletimer(sk);
		rose->condition = 0x00;
		rose->va        = 0;
		rose->vr        = 0;
		rose->vs        = 0;
		rose->vl        = 0;
		rose->state     = ROSE_STATE_3;
		rose_requeue_frames(sk);
		break;

	case ROSE_CLEAR_REQUEST:
		rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
		rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
		rose->neighbour->use--;
		break;

	default:
		break;
	}

	return 0;
}

/*
 * State machine for state 5, Awaiting Call Acceptance State.
 * The handling of the timer(s) is in file rose_timer.c
 * Handling of state 0 and connection release is in af_rose.c.
 */
static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	if (frametype == ROSE_CLEAR_REQUEST) {
		rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
		rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
		rose_sk(sk)->neighbour->use--;
	}

	return 0;
}

/* Higher level upcall for a LAPB frame */
int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
	struct rose_sock *rose = rose_sk(sk);
	int queued = 0, frametype, ns, nr, q, d, m;

	if (rose->state == ROSE_STATE_0)
		return 0;

	frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);

	switch (rose->state) {
	case ROSE_STATE_1:
		queued = rose_state1_machine(sk, skb, frametype);
		break;
	case ROSE_STATE_2:
		queued = rose_state2_machine(sk, skb, frametype);
		break;
	case ROSE_STATE_3:
		queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
		break;
	case ROSE_STATE_4:
		queued = rose_state4_machine(sk, skb, frametype);
		break;
	case ROSE_STATE_5:
		queued = rose_state5_machine(sk, skb, frametype);
		break;
	}

	rose_kick(sk);

	return queued;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This program is free software; you can redistribute it and/or modify
	3	* it under the terms of the GNU General Public License as published by
	4	* the Free Software Foundation; either version 2 of the License, or
	5	* (at your option) any later version.
	6	*
	7	* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
	8	*
	9	* Most of this code is based on the SDL diagrams published in the 7th ARRL
	10	* Computer Networking Conference papers. The diagrams have mistakes in them,
	11	* but are mostly correct. Before you modify the code could you read the SDL
	12	* diagrams as the code is not obvious and probably very easy to break.
	13	*/
	14	#include <linux/errno.h>
	15	#include <linux/types.h>
	16	#include <linux/socket.h>
	17	#include <linux/in.h>
	18	#include <linux/kernel.h>
1da177e4 LT	19	#include <linux/timer.h>
	20	#include <linux/string.h>
	21	#include <linux/sockios.h>
	22	#include <linux/net.h>
	23	#include <net/ax25.h>
	24	#include <linux/inet.h>
	25	#include <linux/netdevice.h>
	26	#include <linux/skbuff.h>
	27	#include <net/sock.h>
c752f073	28	#include <net/tcp_states.h>
1da177e4 LT	29	#include <linux/fcntl.h>
	30	#include <linux/mm.h>
	31	#include <linux/interrupt.h>
	32	#include <net/rose.h>
	33
	34	/*
	35	* State machine for state 1, Awaiting Call Accepted State.
	36	* The handling of the timer(s) is in file rose_timer.c.
	37	* Handling of state 0 and connection release is in af_rose.c.
	38	*/
	39	static int rose_state1_machine(struct sock sk, struct sk_buff skb, int frametype)
	40	{
	41	struct rose_sock *rose = rose_sk(sk);
	42
	43	switch (frametype) {
	44	case ROSE_CALL_ACCEPTED:
	45	rose_stop_timer(sk);
	46	rose_start_idletimer(sk);
	47	rose->condition = 0x00;
	48	rose->vs = 0;
	49	rose->va = 0;
	50	rose->vr = 0;
	51	rose->vl = 0;
	52	rose->state = ROSE_STATE_3;
	53	sk->sk_state = TCP_ESTABLISHED;
	54	if (!sock_flag(sk, SOCK_DEAD))
	55	sk->sk_state_change(sk);
	56	break;
	57
	58	case ROSE_CLEAR_REQUEST:
	59	rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
	60	rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
	61	rose->neighbour->use--;
	62	break;
	63
	64	default:
	65	break;
	66	}
	67
	68	return 0;
	69	}
	70
	71	/*
	72	* State machine for state 2, Awaiting Clear Confirmation State.
	73	* The handling of the timer(s) is in file rose_timer.c
	74	* Handling of state 0 and connection release is in af_rose.c.
	75	*/
	76	static int rose_state2_machine(struct sock sk, struct sk_buff skb, int frametype)
	77	{
	78	struct rose_sock *rose = rose_sk(sk);
	79
	80	switch (frametype) {
	81	case ROSE_CLEAR_REQUEST:
	82	rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
	83	rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
	84	rose->neighbour->use--;
	85	break;
	86
	87	case ROSE_CLEAR_CONFIRMATION:
	88	rose_disconnect(sk, 0, -1, -1);
	89	rose->neighbour->use--;
	90	break;
	91
	92	default:
93	break;
94	}
95
96	return 0;
97	}
98
99	/*
100	* State machine for state 3, Connected State.
101	* The handling of the timer(s) is in file rose_timer.c
102	* Handling of state 0 and connection release is in af_rose.c.
103	*/
104	static int rose_state3_machine(struct sock sk, struct sk_buff skb, int frametype, int ns, int nr, int q, int d, int m)
105	{
106	struct rose_sock *rose = rose_sk(sk);
107	int queued = 0;
108
109	switch (frametype) {
110	case ROSE_RESET_REQUEST:
111	rose_stop_timer(sk);
112	rose_start_idletimer(sk);
113	rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
114	rose->condition = 0x00;
115	rose->vs = 0;
116	rose->vr = 0;
117	rose->va = 0;
118	rose->vl = 0;
119	rose_requeue_frames(sk);
120	break;
121
122	case ROSE_CLEAR_REQUEST:
123	rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
124	rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
125	rose->neighbour->use--;
126	break;
127
128	case ROSE_RR:
129	case ROSE_RNR:
130	if (!rose_validate_nr(sk, nr)) {
131	rose_write_internal(sk, ROSE_RESET_REQUEST);
132	rose->condition = 0x00;
133	rose->vs = 0;
134	rose->vr = 0;
135	rose->va = 0;
136	rose->vl = 0;
137	rose->state = ROSE_STATE_4;
138	rose_start_t2timer(sk);
139	rose_stop_idletimer(sk);
140	} else {
141	rose_frames_acked(sk, nr);
142	if (frametype == ROSE_RNR) {
143	rose->condition \|= ROSE_COND_PEER_RX_BUSY;
144	} else {
145	rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
146	}
147	}
148	break;
149
150	case ROSE_DATA: /* XXX */
151	rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
152	if (!rose_validate_nr(sk, nr)) {
153	rose_write_internal(sk, ROSE_RESET_REQUEST);
154	rose->condition = 0x00;
155	rose->vs = 0;
156	rose->vr = 0;
157	rose->va = 0;
158	rose->vl = 0;
159	rose->state = ROSE_STATE_4;
160	rose_start_t2timer(sk);
161	rose_stop_idletimer(sk);
162	break;
163	}
164	rose_frames_acked(sk, nr);
165	if (ns == rose->vr) {
166	rose_start_idletimer(sk);
f4979fce WB	167	if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
f4979fce WB	168	__sock_queue_rcv_skb(sk, skb) == 0) {
1da177e4 LT	169	rose->vr = (rose->vr + 1) % ROSE_MODULUS;
	170	queued = 1;
	171	} else {
	172	/* Should never happen ! */
	173	rose_write_internal(sk, ROSE_RESET_REQUEST);
	174	rose->condition = 0x00;
	175	rose->vs = 0;
	176	rose->vr = 0;
	177	rose->va = 0;
	178	rose->vl = 0;
	179	rose->state = ROSE_STATE_4;
	180	rose_start_t2timer(sk);
	181	rose_stop_idletimer(sk);
	182	break;
	183	}
	184	if (atomic_read(&sk->sk_rmem_alloc) >
95b7d924	185	(sk->sk_rcvbuf >> 1))
1da177e4 LT	186	rose->condition \|= ROSE_COND_OWN_RX_BUSY;
	187	}
	188	/*
	189	* If the window is full, ack the frame, else start the
	190	* acknowledge hold back timer.
	191	*/
	192	if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
	193	rose->condition &= ~ROSE_COND_ACK_PENDING;
	194	rose_stop_timer(sk);
	195	rose_enquiry_response(sk);
	196	} else {
	197	rose->condition \|= ROSE_COND_ACK_PENDING;
	198	rose_start_hbtimer(sk);
	199	}
	200	break;
	201
	202	default:
	203	printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
	204	break;
	205	}
	206
	207	return queued;
	208	}
	209
	210	/*
	211	* State machine for state 4, Awaiting Reset Confirmation State.
	212	* The handling of the timer(s) is in file rose_timer.c
	213	* Handling of state 0 and connection release is in af_rose.c.
	214	*/
	215	static int rose_state4_machine(struct sock sk, struct sk_buff skb, int frametype)
	216	{
	217	struct rose_sock *rose = rose_sk(sk);
	218
	219	switch (frametype) {
	220	case ROSE_RESET_REQUEST:
	221	rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
a05b8c43	222	/* fall through */
1da177e4 LT	223	case ROSE_RESET_CONFIRMATION:
	224	rose_stop_timer(sk);
	225	rose_start_idletimer(sk);
	226	rose->condition = 0x00;
	227	rose->va = 0;
	228	rose->vr = 0;
	229	rose->vs = 0;
	230	rose->vl = 0;
	231	rose->state = ROSE_STATE_3;
	232	rose_requeue_frames(sk);
	233	break;
	234
	235	case ROSE_CLEAR_REQUEST:
	236	rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
	237	rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
	238	rose->neighbour->use--;
	239	break;
	240
	241	default:
	242	break;
	243	}
	244
	245	return 0;
	246	}
	247
	248	/*
	249	* State machine for state 5, Awaiting Call Acceptance State.
	250	* The handling of the timer(s) is in file rose_timer.c
	251	* Handling of state 0 and connection release is in af_rose.c.
	252	*/
	253	static int rose_state5_machine(struct sock sk, struct sk_buff skb, int frametype)
	254	{
	255	if (frametype == ROSE_CLEAR_REQUEST) {
	256	rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
	257	rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
	258	rose_sk(sk)->neighbour->use--;
	259	}
	260
	261	return 0;
	262	}
	263
	264	/* Higher level upcall for a LAPB frame */
	265	int rose_process_rx_frame(struct sock sk, struct sk_buff skb)
	266	{
	267	struct rose_sock *rose = rose_sk(sk);
	268	int queued = 0, frametype, ns, nr, q, d, m;
	269
	270	if (rose->state == ROSE_STATE_0)
	271	return 0;
	272
	273	frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
	274
	275	switch (rose->state) {
	276	case ROSE_STATE_1:
	277	queued = rose_state1_machine(sk, skb, frametype);
	278	break;
	279	case ROSE_STATE_2:
	280	queued = rose_state2_machine(sk, skb, frametype);
	281	break;
	282	case ROSE_STATE_3:
	283	queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
	284	break;
	285	case ROSE_STATE_4:
	286	queued = rose_state4_machine(sk, skb, frametype);
287	break;
288	case ROSE_STATE_5:
289	queued = rose_state5_machine(sk, skb, frametype);
290	break;
291	}
292
293	rose_kick(sk);
294
295	return queued;
296	}