[linux.git] / net / netrom / nr_in.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright Jonathan Naylor G4KLX ([email protected])
 * Copyright Darryl Miles G7LED ([email protected])
 */
#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 <linux/slab.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/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/netrom.h>

static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
{
	struct sk_buff *skbo, *skbn = skb;
	struct nr_sock *nr = nr_sk(sk);

	skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);

	nr_start_idletimer(sk);

	if (more) {
		nr->fraglen += skb->len;
		skb_queue_tail(&nr->frag_queue, skb);
		return 0;
	}

	if (!more && nr->fraglen > 0) {	/* End of fragment */
		nr->fraglen += skb->len;
		skb_queue_tail(&nr->frag_queue, skb);

		if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
			return 1;

		skb_reset_transport_header(skbn);

		while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
			skb_copy_from_linear_data(skbo,
						  skb_put(skbn, skbo->len),
						  skbo->len);
			kfree_skb(skbo);
		}

		nr->fraglen = 0;
	}

	return sock_queue_rcv_skb(sk, skbn);
}

/*
 * State machine for state 1, Awaiting Connection State.
 * The handling of the timer(s) is in file nr_timer.c.
 * Handling of state 0 and connection release is in netrom.c.
 */
static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
	int frametype)
{
	switch (frametype) {
	case NR_CONNACK: {
		struct nr_sock *nr = nr_sk(sk);

		nr_stop_t1timer(sk);
		nr_start_idletimer(sk);
		nr->your_index = skb->data[17];
		nr->your_id    = skb->data[18];
		nr->vs	       = 0;
		nr->va	       = 0;
		nr->vr	       = 0;
		nr->vl	       = 0;
		nr->state      = NR_STATE_3;
		nr->n2count    = 0;
		nr->window     = skb->data[20];
		sk->sk_state   = TCP_ESTABLISHED;
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
		break;
	}

	case NR_CONNACK | NR_CHOKE_FLAG:
		nr_disconnect(sk, ECONNREFUSED);
		break;

	case NR_RESET:
		if (sysctl_netrom_reset_circuit)
			nr_disconnect(sk, ECONNRESET);
		break;

	default:
		break;
	}
	return 0;
}

/*
 * State machine for state 2, Awaiting Release State.
 * The handling of the timer(s) is in file nr_timer.c
 * Handling of state 0 and connection release is in netrom.c.
 */
static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
	int frametype)
{
	switch (frametype) {
	case NR_CONNACK | NR_CHOKE_FLAG:
		nr_disconnect(sk, ECONNRESET);
		break;

	case NR_DISCREQ:
		nr_write_internal(sk, NR_DISCACK);
		/* fall through */
	case NR_DISCACK:
		nr_disconnect(sk, 0);
		break;

	case NR_RESET:
		if (sysctl_netrom_reset_circuit)
			nr_disconnect(sk, ECONNRESET);
		break;

	default:
		break;
	}
	return 0;
}

/*
 * State machine for state 3, Connected State.
 * The handling of the timer(s) is in file nr_timer.c
 * Handling of state 0 and connection release is in netrom.c.
 */
static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct nr_sock *nrom = nr_sk(sk);
	struct sk_buff_head temp_queue;
	struct sk_buff *skbn;
	unsigned short save_vr;
	unsigned short nr, ns;
	int queued = 0;

	nr = skb->data[18];
	ns = skb->data[17];

	switch (frametype) {
	case NR_CONNREQ:
		nr_write_internal(sk, NR_CONNACK);
		break;

	case NR_DISCREQ:
		nr_write_internal(sk, NR_DISCACK);
		nr_disconnect(sk, 0);
		break;

	case NR_CONNACK | NR_CHOKE_FLAG:
	case NR_DISCACK:
		nr_disconnect(sk, ECONNRESET);
		break;

	case NR_INFOACK:
	case NR_INFOACK | NR_CHOKE_FLAG:
	case NR_INFOACK | NR_NAK_FLAG:
	case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
		if (frametype & NR_CHOKE_FLAG) {
			nrom->condition |= NR_COND_PEER_RX_BUSY;
			nr_start_t4timer(sk);
		} else {
			nrom->condition &= ~NR_COND_PEER_RX_BUSY;
			nr_stop_t4timer(sk);
		}
		if (!nr_validate_nr(sk, nr)) {
			break;
		}
		if (frametype & NR_NAK_FLAG) {
			nr_frames_acked(sk, nr);
			nr_send_nak_frame(sk);
		} else {
			if (nrom->condition & NR_COND_PEER_RX_BUSY) {
				nr_frames_acked(sk, nr);
			} else {
				nr_check_iframes_acked(sk, nr);
			}
		}
		break;

	case NR_INFO:
	case NR_INFO | NR_NAK_FLAG:
	case NR_INFO | NR_CHOKE_FLAG:
	case NR_INFO | NR_MORE_FLAG:
	case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
	case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
	case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
	case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
		if (frametype & NR_CHOKE_FLAG) {
			nrom->condition |= NR_COND_PEER_RX_BUSY;
			nr_start_t4timer(sk);
		} else {
			nrom->condition &= ~NR_COND_PEER_RX_BUSY;
			nr_stop_t4timer(sk);
		}
		if (nr_validate_nr(sk, nr)) {
			if (frametype & NR_NAK_FLAG) {
				nr_frames_acked(sk, nr);
				nr_send_nak_frame(sk);
			} else {
				if (nrom->condition & NR_COND_PEER_RX_BUSY) {
					nr_frames_acked(sk, nr);
				} else {
					nr_check_iframes_acked(sk, nr);
				}
			}
		}
		queued = 1;
		skb_queue_head(&nrom->reseq_queue, skb);
		if (nrom->condition & NR_COND_OWN_RX_BUSY)
			break;
		skb_queue_head_init(&temp_queue);
		do {
			save_vr = nrom->vr;
			while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
				ns = skbn->data[17];
				if (ns == nrom->vr) {
					if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
						nrom->vr = (nrom->vr + 1) % NR_MODULUS;
					} else {
						nrom->condition |= NR_COND_OWN_RX_BUSY;
						skb_queue_tail(&temp_queue, skbn);
					}
				} else if (nr_in_rx_window(sk, ns)) {
					skb_queue_tail(&temp_queue, skbn);
				} else {
					kfree_skb(skbn);
				}
			}
			while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
				skb_queue_tail(&nrom->reseq_queue, skbn);
			}
		} while (save_vr != nrom->vr);
		/*
		 * Window is full, ack it immediately.
		 */
		if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
			nr_enquiry_response(sk);
		} else {
			if (!(nrom->condition & NR_COND_ACK_PENDING)) {
				nrom->condition |= NR_COND_ACK_PENDING;
				nr_start_t2timer(sk);
			}
		}
		break;

	case NR_RESET:
		if (sysctl_netrom_reset_circuit)
			nr_disconnect(sk, ECONNRESET);
		break;

	default:
		break;
	}
	return queued;
}

/* Higher level upcall for a LAPB frame - called with sk locked */
int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
	struct nr_sock *nr = nr_sk(sk);
	int queued = 0, frametype;

	if (nr->state == NR_STATE_0)
		return 0;

	frametype = skb->data[19];

	switch (nr->state) {
	case NR_STATE_1:
		queued = nr_state1_machine(sk, skb, frametype);
		break;
	case NR_STATE_2:
		queued = nr_state2_machine(sk, skb, frametype);
		break;
	case NR_STATE_3:
		queued = nr_state3_machine(sk, skb, frametype);
		break;
	}

	nr_kick(sk);

	return queued;
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
1da177e4 LT	3	*
	4	* Copyright Jonathan Naylor G4KLX ([email protected])
	5	* Copyright Darryl Miles G7LED ([email protected])
	6	*/
	7	#include <linux/errno.h>
	8	#include <linux/types.h>
	9	#include <linux/socket.h>
	10	#include <linux/in.h>
	11	#include <linux/kernel.h>
1da177e4 LT	12	#include <linux/timer.h>
	13	#include <linux/string.h>
	14	#include <linux/sockios.h>
	15	#include <linux/net.h>
5a0e3ad6	16	#include <linux/slab.h>
1da177e4 LT	17	#include <net/ax25.h>
	18	#include <linux/inet.h>
	19	#include <linux/netdevice.h>
	20	#include <linux/skbuff.h>
	21	#include <net/sock.h>
c752f073	22	#include <net/tcp_states.h>
dc8e5416	23	#include <linux/uaccess.h>
1da177e4 LT	24	#include <linux/fcntl.h>
	25	#include <linux/mm.h>
	26	#include <linux/interrupt.h>
	27	#include <net/netrom.h>
	28
	29	static int nr_queue_rx_frame(struct sock sk, struct sk_buff skb, int more)
	30	{
	31	struct sk_buff skbo, skbn = skb;
	32	struct nr_sock *nr = nr_sk(sk);
	33
	34	skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
	35
	36	nr_start_idletimer(sk);
	37
	38	if (more) {
	39	nr->fraglen += skb->len;
	40	skb_queue_tail(&nr->frag_queue, skb);
	41	return 0;
	42	}
	43
	44	if (!more && nr->fraglen > 0) { /* End of fragment */
	45	nr->fraglen += skb->len;
	46	skb_queue_tail(&nr->frag_queue, skb);
	47
	48	if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
	49	return 1;
	50
badff6d0	51	skb_reset_transport_header(skbn);
1da177e4 LT	52
1da177e4 LT	53	while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
1a4e2d09 ACM	54	skb_copy_from_linear_data(skbo,
	55	skb_put(skbn, skbo->len),
	56	skbo->len);
1da177e4 LT	57	kfree_skb(skbo);
	58	}
	59
	60	nr->fraglen = 0;
	61	}
	62
	63	return sock_queue_rcv_skb(sk, skbn);
	64	}
	65
	66	/*
	67	* State machine for state 1, Awaiting Connection State.
	68	* The handling of the timer(s) is in file nr_timer.c.
	69	* Handling of state 0 and connection release is in netrom.c.
	70	*/
	71	static int nr_state1_machine(struct sock sk, struct sk_buff skb,
	72	int frametype)
	73	{
	74	switch (frametype) {
	75	case NR_CONNACK: {
	76	struct nr_sock *nr = nr_sk(sk);
	77
	78	nr_stop_t1timer(sk);
	79	nr_start_idletimer(sk);
	80	nr->your_index = skb->data[17];
	81	nr->your_id = skb->data[18];
	82	nr->vs = 0;
	83	nr->va = 0;
	84	nr->vr = 0;
	85	nr->vl = 0;
	86	nr->state = NR_STATE_3;
	87	nr->n2count = 0;
	88	nr->window = skb->data[20];
	89	sk->sk_state = TCP_ESTABLISHED;
	90	if (!sock_flag(sk, SOCK_DEAD))
	91	sk->sk_state_change(sk);
	92	break;
	93	}
	94
	95	case NR_CONNACK \| NR_CHOKE_FLAG:
	96	nr_disconnect(sk, ECONNREFUSED);
	97	break;
	98
e21ce8c7	99	case NR_RESET:
0d77d59f	100	if (sysctl_netrom_reset_circuit)
e21ce8c7 RB	101	nr_disconnect(sk, ECONNRESET);
	102	break;
	103
1da177e4 LT	104	default:
	105	break;
	106	}
	107	return 0;
	108	}
	109
	110	/*
	111	* State machine for state 2, Awaiting Release State.
	112	* The handling of the timer(s) is in file nr_timer.c
	113	* Handling of state 0 and connection release is in netrom.c.
	114	*/
	115	static int nr_state2_machine(struct sock sk, struct sk_buff skb,
	116	int frametype)
	117	{
	118	switch (frametype) {
	119	case NR_CONNACK \| NR_CHOKE_FLAG:
	120	nr_disconnect(sk, ECONNRESET);
	121	break;
	122
	123	case NR_DISCREQ:
	124	nr_write_internal(sk, NR_DISCACK);
e28101a3	125	/* fall through */
1da177e4 LT	126	case NR_DISCACK:
	127	nr_disconnect(sk, 0);
	128	break;
	129
e21ce8c7	130	case NR_RESET:
0d77d59f	131	if (sysctl_netrom_reset_circuit)
e21ce8c7 RB	132	nr_disconnect(sk, ECONNRESET);
	133	break;
	134
1da177e4 LT	135	default:
	136	break;
	137	}
	138	return 0;
	139	}
	140
	141	/*
	142	* State machine for state 3, Connected State.
	143	* The handling of the timer(s) is in file nr_timer.c
	144	* Handling of state 0 and connection release is in netrom.c.
	145	*/
	146	static int nr_state3_machine(struct sock sk, struct sk_buff skb, int frametype)
	147	{
	148	struct nr_sock *nrom = nr_sk(sk);
	149	struct sk_buff_head temp_queue;
	150	struct sk_buff *skbn;
	151	unsigned short save_vr;
	152	unsigned short nr, ns;
	153	int queued = 0;
	154
	155	nr = skb->data[18];
	156	ns = skb->data[17];
	157
	158	switch (frametype) {
	159	case NR_CONNREQ:
	160	nr_write_internal(sk, NR_CONNACK);
	161	break;
	162
	163	case NR_DISCREQ:
	164	nr_write_internal(sk, NR_DISCACK);
	165	nr_disconnect(sk, 0);
	166	break;
	167
	168	case NR_CONNACK \| NR_CHOKE_FLAG:
	169	case NR_DISCACK:
	170	nr_disconnect(sk, ECONNRESET);
	171	break;
	172
	173	case NR_INFOACK:
	174	case NR_INFOACK \| NR_CHOKE_FLAG:
	175	case NR_INFOACK \| NR_NAK_FLAG:
	176	case NR_INFOACK \| NR_NAK_FLAG \| NR_CHOKE_FLAG:
	177	if (frametype & NR_CHOKE_FLAG) {
	178	nrom->condition \|= NR_COND_PEER_RX_BUSY;
	179	nr_start_t4timer(sk);
	180	} else {
	181	nrom->condition &= ~NR_COND_PEER_RX_BUSY;
	182	nr_stop_t4timer(sk);
	183	}
	184	if (!nr_validate_nr(sk, nr)) {
	185	break;
	186	}
	187	if (frametype & NR_NAK_FLAG) {
	188	nr_frames_acked(sk, nr);
	189	nr_send_nak_frame(sk);
	190	} else {
	191	if (nrom->condition & NR_COND_PEER_RX_BUSY) {
	192	nr_frames_acked(sk, nr);
	193	} else {
	194	nr_check_iframes_acked(sk, nr);
	195	}
	196	}
	197	break;
	198
199	case NR_INFO:
200	case NR_INFO \| NR_NAK_FLAG:
201	case NR_INFO \| NR_CHOKE_FLAG:
202	case NR_INFO \| NR_MORE_FLAG:
203	case NR_INFO \| NR_NAK_FLAG \| NR_CHOKE_FLAG:
204	case NR_INFO \| NR_CHOKE_FLAG \| NR_MORE_FLAG:
205	case NR_INFO \| NR_NAK_FLAG \| NR_MORE_FLAG:
206	case NR_INFO \| NR_NAK_FLAG \| NR_CHOKE_FLAG \| NR_MORE_FLAG:
207	if (frametype & NR_CHOKE_FLAG) {
208	nrom->condition \|= NR_COND_PEER_RX_BUSY;
209	nr_start_t4timer(sk);
210	} else {
211	nrom->condition &= ~NR_COND_PEER_RX_BUSY;
212	nr_stop_t4timer(sk);
213	}
214	if (nr_validate_nr(sk, nr)) {
215	if (frametype & NR_NAK_FLAG) {
216	nr_frames_acked(sk, nr);
217	nr_send_nak_frame(sk);
218	} else {
219	if (nrom->condition & NR_COND_PEER_RX_BUSY) {
220	nr_frames_acked(sk, nr);
221	} else {
222	nr_check_iframes_acked(sk, nr);
223	}
224	}
225	}
226	queued = 1;
227	skb_queue_head(&nrom->reseq_queue, skb);
228	if (nrom->condition & NR_COND_OWN_RX_BUSY)
229	break;
230	skb_queue_head_init(&temp_queue);
231	do {
232	save_vr = nrom->vr;
233	while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
234	ns = skbn->data[17];
235	if (ns == nrom->vr) {
236	if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
237	nrom->vr = (nrom->vr + 1) % NR_MODULUS;
238	} else {
239	nrom->condition \|= NR_COND_OWN_RX_BUSY;
240	skb_queue_tail(&temp_queue, skbn);
241	}
242	} else if (nr_in_rx_window(sk, ns)) {
243	skb_queue_tail(&temp_queue, skbn);
244	} else {
245	kfree_skb(skbn);
246	}
247	}
248	while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
249	skb_queue_tail(&nrom->reseq_queue, skbn);
250	}
251	} while (save_vr != nrom->vr);
252	/*
253	* Window is full, ack it immediately.
254	*/
255	if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
256	nr_enquiry_response(sk);
257	} else {
258	if (!(nrom->condition & NR_COND_ACK_PENDING)) {
259	nrom->condition \|= NR_COND_ACK_PENDING;
260	nr_start_t2timer(sk);
261	}
262	}
263	break;
264
e21ce8c7	265	case NR_RESET:
0d77d59f	266	if (sysctl_netrom_reset_circuit)
e21ce8c7 RB	267	nr_disconnect(sk, ECONNRESET);
	268	break;
	269
1da177e4 LT	270	default:
	271	break;
	272	}
	273	return queued;
	274	}
	275
	276	/* Higher level upcall for a LAPB frame - called with sk locked */
	277	int nr_process_rx_frame(struct sock sk, struct sk_buff skb)
	278	{
	279	struct nr_sock *nr = nr_sk(sk);
	280	int queued = 0, frametype;
	281
	282	if (nr->state == NR_STATE_0)
	283	return 0;
	284
	285	frametype = skb->data[19];
	286
	287	switch (nr->state) {
	288	case NR_STATE_1:
	289	queued = nr_state1_machine(sk, skb, frametype);
	290	break;
	291	case NR_STATE_2:
	292	queued = nr_state2_machine(sk, skb, frametype);
	293	break;
	294	case NR_STATE_3:
	295	queued = nr_state3_machine(sk, skb, frametype);
	296	break;
	297	}
	298
	299	nr_kick(sk);
	300
	301	return queued;
	302	}