[linux-2.6-block.git] / net / lapb / lapb_out.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	LAPB release 002
 *
 *	This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *	History
 *	LAPB 001	Jonathan Naylor	Started Coding
 *	LAPB 002	Jonathan Naylor	New timer architecture.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/inet.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/lapb.h>

/*
 *  This procedure is passed a buffer descriptor for an iframe. It builds
 *  the rest of the control part of the frame and then writes it out.
 */
static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
{
	unsigned char *frame;

	if (!skb)
		return;

	if (lapb->mode & LAPB_EXTENDED) {
		frame = skb_push(skb, 2);

		frame[0] = LAPB_I;
		frame[0] |= lapb->vs << 1;
		frame[1] = poll_bit ? LAPB_EPF : 0;
		frame[1] |= lapb->vr << 1;
	} else {
		frame = skb_push(skb, 1);

		*frame = LAPB_I;
		*frame |= poll_bit ? LAPB_SPF : 0;
		*frame |= lapb->vr << 5;
		*frame |= lapb->vs << 1;
	}

	lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n",
		 lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);

	lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
}

void lapb_kick(struct lapb_cb *lapb)
{
	struct sk_buff *skb, *skbn;
	unsigned short modulus, start, end;

	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
	start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs;
	end   = (lapb->va + lapb->window) % modulus;

	if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) &&
	    start != end && skb_peek(&lapb->write_queue)) {
		lapb->vs = start;

		/*
		 * Dequeue the frame and copy it.
		 */
		skb = skb_dequeue(&lapb->write_queue);

		do {
			if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
				skb_queue_head(&lapb->write_queue, skb);
				break;
			}

			if (skb->sk)
				skb_set_owner_w(skbn, skb->sk);

			/*
			 * Transmit the frame copy.
			 */
			lapb_send_iframe(lapb, skbn, LAPB_POLLOFF);

			lapb->vs = (lapb->vs + 1) % modulus;

			/*
			 * Requeue the original data frame.
			 */
			skb_queue_tail(&lapb->ack_queue, skb);

		} while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL);

		lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;

		if (!lapb_t1timer_running(lapb))
			lapb_start_t1timer(lapb);
	}
}

void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type)
{
	unsigned char *ptr;

	ptr = skb_push(skb, 1);

	if (lapb->mode & LAPB_MLP) {
		if (lapb->mode & LAPB_DCE) {
			if (type == LAPB_COMMAND)
				*ptr = LAPB_ADDR_C;
			if (type == LAPB_RESPONSE)
				*ptr = LAPB_ADDR_D;
		} else {
			if (type == LAPB_COMMAND)
				*ptr = LAPB_ADDR_D;
			if (type == LAPB_RESPONSE)
				*ptr = LAPB_ADDR_C;
		}
	} else {
		if (lapb->mode & LAPB_DCE) {
			if (type == LAPB_COMMAND)
				*ptr = LAPB_ADDR_A;
			if (type == LAPB_RESPONSE)
				*ptr = LAPB_ADDR_B;
		} else {
			if (type == LAPB_COMMAND)
				*ptr = LAPB_ADDR_B;
			if (type == LAPB_RESPONSE)
				*ptr = LAPB_ADDR_A;
		}
	}

	lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data);

	if (!lapb_data_transmit(lapb, skb))
		kfree_skb(skb);
}

void lapb_establish_data_link(struct lapb_cb *lapb)
{
	lapb->condition = 0x00;
	lapb->n2count   = 0;

	if (lapb->mode & LAPB_EXTENDED) {
		lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state);
		lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
	} else {
		lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state);
		lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
	}

	lapb_start_t1timer(lapb);
	lapb_stop_t2timer(lapb);
}

void lapb_enquiry_response(struct lapb_cb *lapb)
{
	lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n",
		 lapb->dev, lapb->state, lapb->vr);

	lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);

	lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
}

void lapb_timeout_response(struct lapb_cb *lapb)
{
	lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n",
		 lapb->dev, lapb->state, lapb->vr);
	lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);

	lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
}

void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr)
{
	if (lapb->vs == nr) {
		lapb_frames_acked(lapb, nr);
		lapb_stop_t1timer(lapb);
		lapb->n2count = 0;
	} else if (lapb->va != nr) {
		lapb_frames_acked(lapb, nr);
		lapb_start_t1timer(lapb);
	}
}

void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf)
{
	if (type == LAPB_COMMAND && pf)
		lapb_enquiry_response(lapb);
}
Commit	Line	Data
ee5d8f4d	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* LAPB release 002
	4	*
	5	* This code REQUIRES 2.1.15 or higher/ NET3.038
	6	*
1da177e4 LT	7	* History
	8	* LAPB 001 Jonathan Naylor Started Coding
	9	* LAPB 002 Jonathan Naylor New timer architecture.
	10	*/
	11
a508da6c JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
a508da6c JP	13
1da177e4 LT	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 <linux/inet.h>
	24	#include <linux/skbuff.h>
5a0e3ad6	25	#include <linux/slab.h>
1da177e4	26	#include <net/sock.h>
7c0f6ba6	27	#include <linux/uaccess.h>
1da177e4 LT	28	#include <linux/fcntl.h>
	29	#include <linux/mm.h>
	30	#include <linux/interrupt.h>
	31	#include <net/lapb.h>
	32
56d6c3d7	33	/*
1da177e4 LT	34	* This procedure is passed a buffer descriptor for an iframe. It builds
	35	* the rest of the control part of the frame and then writes it out.
	36	*/
	37	static void lapb_send_iframe(struct lapb_cb lapb, struct sk_buff skb, int poll_bit)
	38	{
	39	unsigned char *frame;
	40
	41	if (!skb)
	42	return;
	43
	44	if (lapb->mode & LAPB_EXTENDED) {
	45	frame = skb_push(skb, 2);
	46
	47	frame[0] = LAPB_I;
	48	frame[0] \|= lapb->vs << 1;
	49	frame[1] = poll_bit ? LAPB_EPF : 0;
	50	frame[1] \|= lapb->vr << 1;
	51	} else {
	52	frame = skb_push(skb, 1);
	53
	54	*frame = LAPB_I;
	55	*frame \|= poll_bit ? LAPB_SPF : 0;
	56	*frame \|= lapb->vr << 5;
	57	*frame \|= lapb->vs << 1;
	58	}
	59
a508da6c JP	60	lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n",
a508da6c JP	61	lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);
1da177e4	62
56d6c3d7	63	lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
1da177e4 LT	64	}
	65
	66	void lapb_kick(struct lapb_cb *lapb)
	67	{
	68	struct sk_buff skb, skbn;
	69	unsigned short modulus, start, end;
	70
	71	modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
	72	start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs;
	73	end = (lapb->va + lapb->window) % modulus;
	74
	75	if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) &&
	76	start != end && skb_peek(&lapb->write_queue)) {
	77	lapb->vs = start;
	78
	79	/*
	80	* Dequeue the frame and copy it.
	81	*/
	82	skb = skb_dequeue(&lapb->write_queue);
	83
	84	do {
	85	if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
	86	skb_queue_head(&lapb->write_queue, skb);
	87	break;
	88	}
	89
	90	if (skb->sk)
	91	skb_set_owner_w(skbn, skb->sk);
	92
	93	/*
	94	* Transmit the frame copy.
	95	*/
	96	lapb_send_iframe(lapb, skbn, LAPB_POLLOFF);
	97
	98	lapb->vs = (lapb->vs + 1) % modulus;
	99
	100	/*
	101	* Requeue the original data frame.
	102	*/
	103	skb_queue_tail(&lapb->ack_queue, skb);
	104
	105	} while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL);
	106
	107	lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
	108
	109	if (!lapb_t1timer_running(lapb))
	110	lapb_start_t1timer(lapb);
	111	}
	112	}
	113
	114	void lapb_transmit_buffer(struct lapb_cb lapb, struct sk_buff skb, int type)
	115	{
	116	unsigned char *ptr;
	117
	118	ptr = skb_push(skb, 1);
	119
	120	if (lapb->mode & LAPB_MLP) {
	121	if (lapb->mode & LAPB_DCE) {
	122	if (type == LAPB_COMMAND)
	123	*ptr = LAPB_ADDR_C;
	124	if (type == LAPB_RESPONSE)
	125	*ptr = LAPB_ADDR_D;
	126	} else {
	127	if (type == LAPB_COMMAND)
128	*ptr = LAPB_ADDR_D;
129	if (type == LAPB_RESPONSE)
130	*ptr = LAPB_ADDR_C;
131	}
132	} else {
133	if (lapb->mode & LAPB_DCE) {
134	if (type == LAPB_COMMAND)
135	*ptr = LAPB_ADDR_A;
136	if (type == LAPB_RESPONSE)
137	*ptr = LAPB_ADDR_B;
138	} else {
139	if (type == LAPB_COMMAND)
140	*ptr = LAPB_ADDR_B;
141	if (type == LAPB_RESPONSE)
142	*ptr = LAPB_ADDR_A;
143	}
144	}
145
0d08df6c	146	lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data);
1da177e4 LT	147
	148	if (!lapb_data_transmit(lapb, skb))
	149	kfree_skb(skb);
	150	}
	151
	152	void lapb_establish_data_link(struct lapb_cb *lapb)
	153	{
	154	lapb->condition = 0x00;
	155	lapb->n2count = 0;
	156
	157	if (lapb->mode & LAPB_EXTENDED) {
a508da6c	158	lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state);
1da177e4 LT	159	lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
1da177e4 LT	160	} else {
a508da6c	161	lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state);
1da177e4 LT	162	lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
	163	}
	164
	165	lapb_start_t1timer(lapb);
	166	lapb_stop_t2timer(lapb);
	167	}
	168
	169	void lapb_enquiry_response(struct lapb_cb *lapb)
	170	{
a508da6c JP	171	lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n",
a508da6c JP	172	lapb->dev, lapb->state, lapb->vr);
1da177e4 LT	173
	174	lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);
	175
	176	lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
	177	}
	178
	179	void lapb_timeout_response(struct lapb_cb *lapb)
	180	{
a508da6c JP	181	lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n",
a508da6c JP	182	lapb->dev, lapb->state, lapb->vr);
1da177e4 LT	183	lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
	184
	185	lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
	186	}
	187
	188	void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr)
	189	{
	190	if (lapb->vs == nr) {
	191	lapb_frames_acked(lapb, nr);
	192	lapb_stop_t1timer(lapb);
	193	lapb->n2count = 0;
	194	} else if (lapb->va != nr) {
	195	lapb_frames_acked(lapb, nr);
	196	lapb_start_t1timer(lapb);
	197	}
	198	}
	199
	200	void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf)
	201	{
	202	if (type == LAPB_COMMAND && pf)
	203	lapb_enquiry_response(lapb);
	204	}