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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * LAPB release 002
4 *
5 * This code REQUIRES 2.1.15 or higher/ NET3.038
6 *
7 * History
8 * LAPB 001 Jonathan Naylor Started Coding
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/errno.h>
14#include <linux/types.h>
15#include <linux/socket.h>
16#include <linux/in.h>
17#include <linux/kernel.h>
18#include <linux/timer.h>
19#include <linux/string.h>
20#include <linux/sockios.h>
21#include <linux/net.h>
22#include <linux/inet.h>
23#include <linux/skbuff.h>
24#include <linux/slab.h>
25#include <net/sock.h>
26#include <linux/uaccess.h>
27#include <linux/fcntl.h>
28#include <linux/mm.h>
29#include <linux/interrupt.h>
30#include <net/lapb.h>
31
32/*
33 * This routine purges all the queues of frames.
34 */
35void lapb_clear_queues(struct lapb_cb *lapb)
36{
37 skb_queue_purge(&lapb->write_queue);
38 skb_queue_purge(&lapb->ack_queue);
39}
40
41/*
42 * This routine purges the input queue of those frames that have been
43 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
44 * SDL diagram.
45 */
46void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr)
47{
48 struct sk_buff *skb;
49 int modulus;
50
51 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
52
53 /*
54 * Remove all the ack-ed frames from the ack queue.
55 */
56 if (lapb->va != nr)
57 while (skb_peek(&lapb->ack_queue) && lapb->va != nr) {
58 skb = skb_dequeue(&lapb->ack_queue);
59 kfree_skb(skb);
60 lapb->va = (lapb->va + 1) % modulus;
61 }
62}
63
64void lapb_requeue_frames(struct lapb_cb *lapb)
65{
66 struct sk_buff *skb, *skb_prev = NULL;
67
68 /*
69 * Requeue all the un-ack-ed frames on the output queue to be picked
70 * up by lapb_kick called from the timer. This arrangement handles the
71 * possibility of an empty output queue.
72 */
73 while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) {
74 if (!skb_prev)
75 skb_queue_head(&lapb->write_queue, skb);
76 else
77 skb_append(skb_prev, skb, &lapb->write_queue);
78 skb_prev = skb;
79 }
80}
81
82/*
83 * Validate that the value of nr is between va and vs. Return true or
84 * false for testing.
85 */
86int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr)
87{
88 unsigned short vc = lapb->va;
89 int modulus;
90
91 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
92
93 while (vc != lapb->vs) {
94 if (nr == vc)
95 return 1;
96 vc = (vc + 1) % modulus;
97 }
98
99 return nr == lapb->vs;
100}
101
102/*
103 * This routine is the centralised routine for parsing the control
104 * information for the different frame formats.
105 */
106int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb,
107 struct lapb_frame *frame)
108{
109 frame->type = LAPB_ILLEGAL;
110
111 lapb_dbg(2, "(%p) S%d RX %3ph\n", lapb->dev, lapb->state, skb->data);
112
113 /* We always need to look at 2 bytes, sometimes we need
114 * to look at 3 and those cases are handled below.
115 */
116 if (!pskb_may_pull(skb, 2))
117 return -1;
118
119 if (lapb->mode & LAPB_MLP) {
120 if (lapb->mode & LAPB_DCE) {
121 if (skb->data[0] == LAPB_ADDR_D)
122 frame->cr = LAPB_COMMAND;
123 if (skb->data[0] == LAPB_ADDR_C)
124 frame->cr = LAPB_RESPONSE;
125 } else {
126 if (skb->data[0] == LAPB_ADDR_C)
127 frame->cr = LAPB_COMMAND;
128 if (skb->data[0] == LAPB_ADDR_D)
129 frame->cr = LAPB_RESPONSE;
130 }
131 } else {
132 if (lapb->mode & LAPB_DCE) {
133 if (skb->data[0] == LAPB_ADDR_B)
134 frame->cr = LAPB_COMMAND;
135 if (skb->data[0] == LAPB_ADDR_A)
136 frame->cr = LAPB_RESPONSE;
137 } else {
138 if (skb->data[0] == LAPB_ADDR_A)
139 frame->cr = LAPB_COMMAND;
140 if (skb->data[0] == LAPB_ADDR_B)
141 frame->cr = LAPB_RESPONSE;
142 }
143 }
144
145 skb_pull(skb, 1);
146
147 if (lapb->mode & LAPB_EXTENDED) {
148 if (!(skb->data[0] & LAPB_S)) {
149 if (!pskb_may_pull(skb, 2))
150 return -1;
151 /*
152 * I frame - carries NR/NS/PF
153 */
154 frame->type = LAPB_I;
155 frame->ns = (skb->data[0] >> 1) & 0x7F;
156 frame->nr = (skb->data[1] >> 1) & 0x7F;
157 frame->pf = skb->data[1] & LAPB_EPF;
158 frame->control[0] = skb->data[0];
159 frame->control[1] = skb->data[1];
160 skb_pull(skb, 2);
161 } else if ((skb->data[0] & LAPB_U) == 1) {
162 if (!pskb_may_pull(skb, 2))
163 return -1;
164 /*
165 * S frame - take out PF/NR
166 */
167 frame->type = skb->data[0] & 0x0F;
168 frame->nr = (skb->data[1] >> 1) & 0x7F;
169 frame->pf = skb->data[1] & LAPB_EPF;
170 frame->control[0] = skb->data[0];
171 frame->control[1] = skb->data[1];
172 skb_pull(skb, 2);
173 } else if ((skb->data[0] & LAPB_U) == 3) {
174 /*
175 * U frame - take out PF
176 */
177 frame->type = skb->data[0] & ~LAPB_SPF;
178 frame->pf = skb->data[0] & LAPB_SPF;
179 frame->control[0] = skb->data[0];
180 frame->control[1] = 0x00;
181 skb_pull(skb, 1);
182 }
183 } else {
184 if (!(skb->data[0] & LAPB_S)) {
185 /*
186 * I frame - carries NR/NS/PF
187 */
188 frame->type = LAPB_I;
189 frame->ns = (skb->data[0] >> 1) & 0x07;
190 frame->nr = (skb->data[0] >> 5) & 0x07;
191 frame->pf = skb->data[0] & LAPB_SPF;
192 } else if ((skb->data[0] & LAPB_U) == 1) {
193 /*
194 * S frame - take out PF/NR
195 */
196 frame->type = skb->data[0] & 0x0F;
197 frame->nr = (skb->data[0] >> 5) & 0x07;
198 frame->pf = skb->data[0] & LAPB_SPF;
199 } else if ((skb->data[0] & LAPB_U) == 3) {
200 /*
201 * U frame - take out PF
202 */
203 frame->type = skb->data[0] & ~LAPB_SPF;
204 frame->pf = skb->data[0] & LAPB_SPF;
205 }
206
207 frame->control[0] = skb->data[0];
208
209 skb_pull(skb, 1);
210 }
211
212 return 0;
213}
214
215/*
216 * This routine is called when the HDLC layer internally generates a
217 * command or response for the remote machine ( eg. RR, UA etc. ).
218 * Only supervisory or unnumbered frames are processed, FRMRs are handled
219 * by lapb_transmit_frmr below.
220 */
221void lapb_send_control(struct lapb_cb *lapb, int frametype,
222 int poll_bit, int type)
223{
224 struct sk_buff *skb;
225 unsigned char *dptr;
226
227 if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL)
228 return;
229
230 skb_reserve(skb, LAPB_HEADER_LEN + 1);
231
232 if (lapb->mode & LAPB_EXTENDED) {
233 if ((frametype & LAPB_U) == LAPB_U) {
234 dptr = skb_put(skb, 1);
235 *dptr = frametype;
236 *dptr |= poll_bit ? LAPB_SPF : 0;
237 } else {
238 dptr = skb_put(skb, 2);
239 dptr[0] = frametype;
240 dptr[1] = (lapb->vr << 1);
241 dptr[1] |= poll_bit ? LAPB_EPF : 0;
242 }
243 } else {
244 dptr = skb_put(skb, 1);
245 *dptr = frametype;
246 *dptr |= poll_bit ? LAPB_SPF : 0;
247 if ((frametype & LAPB_U) == LAPB_S) /* S frames carry NR */
248 *dptr |= (lapb->vr << 5);
249 }
250
251 lapb_transmit_buffer(lapb, skb, type);
252}
253
254/*
255 * This routine generates FRMRs based on information previously stored in
256 * the LAPB control block.
257 */
258void lapb_transmit_frmr(struct lapb_cb *lapb)
259{
260 struct sk_buff *skb;
261 unsigned char *dptr;
262
263 if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL)
264 return;
265
266 skb_reserve(skb, LAPB_HEADER_LEN + 1);
267
268 if (lapb->mode & LAPB_EXTENDED) {
269 dptr = skb_put(skb, 6);
270 *dptr++ = LAPB_FRMR;
271 *dptr++ = lapb->frmr_data.control[0];
272 *dptr++ = lapb->frmr_data.control[1];
273 *dptr++ = (lapb->vs << 1) & 0xFE;
274 *dptr = (lapb->vr << 1) & 0xFE;
275 if (lapb->frmr_data.cr == LAPB_RESPONSE)
276 *dptr |= 0x01;
277 dptr++;
278 *dptr++ = lapb->frmr_type;
279
280 lapb_dbg(1, "(%p) S%d TX FRMR %5ph\n",
281 lapb->dev, lapb->state,
282 &skb->data[1]);
283 } else {
284 dptr = skb_put(skb, 4);
285 *dptr++ = LAPB_FRMR;
286 *dptr++ = lapb->frmr_data.control[0];
287 *dptr = (lapb->vs << 1) & 0x0E;
288 *dptr |= (lapb->vr << 5) & 0xE0;
289 if (lapb->frmr_data.cr == LAPB_RESPONSE)
290 *dptr |= 0x10;
291 dptr++;
292 *dptr++ = lapb->frmr_type;
293
294 lapb_dbg(1, "(%p) S%d TX FRMR %3ph\n",
295 lapb->dev, lapb->state, &skb->data[1]);
296 }
297
298 lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE);
299}
1/*
2 * LAPB release 002
3 *
4 * This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * History
13 * LAPB 001 Jonathan Naylor Started Coding
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/errno.h>
19#include <linux/types.h>
20#include <linux/socket.h>
21#include <linux/in.h>
22#include <linux/kernel.h>
23#include <linux/timer.h>
24#include <linux/string.h>
25#include <linux/sockios.h>
26#include <linux/net.h>
27#include <linux/inet.h>
28#include <linux/skbuff.h>
29#include <linux/slab.h>
30#include <net/sock.h>
31#include <linux/uaccess.h>
32#include <linux/fcntl.h>
33#include <linux/mm.h>
34#include <linux/interrupt.h>
35#include <net/lapb.h>
36
37/*
38 * This routine purges all the queues of frames.
39 */
40void lapb_clear_queues(struct lapb_cb *lapb)
41{
42 skb_queue_purge(&lapb->write_queue);
43 skb_queue_purge(&lapb->ack_queue);
44}
45
46/*
47 * This routine purges the input queue of those frames that have been
48 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
49 * SDL diagram.
50 */
51void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr)
52{
53 struct sk_buff *skb;
54 int modulus;
55
56 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
57
58 /*
59 * Remove all the ack-ed frames from the ack queue.
60 */
61 if (lapb->va != nr)
62 while (skb_peek(&lapb->ack_queue) && lapb->va != nr) {
63 skb = skb_dequeue(&lapb->ack_queue);
64 kfree_skb(skb);
65 lapb->va = (lapb->va + 1) % modulus;
66 }
67}
68
69void lapb_requeue_frames(struct lapb_cb *lapb)
70{
71 struct sk_buff *skb, *skb_prev = NULL;
72
73 /*
74 * Requeue all the un-ack-ed frames on the output queue to be picked
75 * up by lapb_kick called from the timer. This arrangement handles the
76 * possibility of an empty output queue.
77 */
78 while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) {
79 if (!skb_prev)
80 skb_queue_head(&lapb->write_queue, skb);
81 else
82 skb_append(skb_prev, skb, &lapb->write_queue);
83 skb_prev = skb;
84 }
85}
86
87/*
88 * Validate that the value of nr is between va and vs. Return true or
89 * false for testing.
90 */
91int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr)
92{
93 unsigned short vc = lapb->va;
94 int modulus;
95
96 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
97
98 while (vc != lapb->vs) {
99 if (nr == vc)
100 return 1;
101 vc = (vc + 1) % modulus;
102 }
103
104 return nr == lapb->vs;
105}
106
107/*
108 * This routine is the centralised routine for parsing the control
109 * information for the different frame formats.
110 */
111int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb,
112 struct lapb_frame *frame)
113{
114 frame->type = LAPB_ILLEGAL;
115
116 lapb_dbg(2, "(%p) S%d RX %3ph\n", lapb->dev, lapb->state, skb->data);
117
118 /* We always need to look at 2 bytes, sometimes we need
119 * to look at 3 and those cases are handled below.
120 */
121 if (!pskb_may_pull(skb, 2))
122 return -1;
123
124 if (lapb->mode & LAPB_MLP) {
125 if (lapb->mode & LAPB_DCE) {
126 if (skb->data[0] == LAPB_ADDR_D)
127 frame->cr = LAPB_COMMAND;
128 if (skb->data[0] == LAPB_ADDR_C)
129 frame->cr = LAPB_RESPONSE;
130 } else {
131 if (skb->data[0] == LAPB_ADDR_C)
132 frame->cr = LAPB_COMMAND;
133 if (skb->data[0] == LAPB_ADDR_D)
134 frame->cr = LAPB_RESPONSE;
135 }
136 } else {
137 if (lapb->mode & LAPB_DCE) {
138 if (skb->data[0] == LAPB_ADDR_B)
139 frame->cr = LAPB_COMMAND;
140 if (skb->data[0] == LAPB_ADDR_A)
141 frame->cr = LAPB_RESPONSE;
142 } else {
143 if (skb->data[0] == LAPB_ADDR_A)
144 frame->cr = LAPB_COMMAND;
145 if (skb->data[0] == LAPB_ADDR_B)
146 frame->cr = LAPB_RESPONSE;
147 }
148 }
149
150 skb_pull(skb, 1);
151
152 if (lapb->mode & LAPB_EXTENDED) {
153 if (!(skb->data[0] & LAPB_S)) {
154 if (!pskb_may_pull(skb, 2))
155 return -1;
156 /*
157 * I frame - carries NR/NS/PF
158 */
159 frame->type = LAPB_I;
160 frame->ns = (skb->data[0] >> 1) & 0x7F;
161 frame->nr = (skb->data[1] >> 1) & 0x7F;
162 frame->pf = skb->data[1] & LAPB_EPF;
163 frame->control[0] = skb->data[0];
164 frame->control[1] = skb->data[1];
165 skb_pull(skb, 2);
166 } else if ((skb->data[0] & LAPB_U) == 1) {
167 if (!pskb_may_pull(skb, 2))
168 return -1;
169 /*
170 * S frame - take out PF/NR
171 */
172 frame->type = skb->data[0] & 0x0F;
173 frame->nr = (skb->data[1] >> 1) & 0x7F;
174 frame->pf = skb->data[1] & LAPB_EPF;
175 frame->control[0] = skb->data[0];
176 frame->control[1] = skb->data[1];
177 skb_pull(skb, 2);
178 } else if ((skb->data[0] & LAPB_U) == 3) {
179 /*
180 * U frame - take out PF
181 */
182 frame->type = skb->data[0] & ~LAPB_SPF;
183 frame->pf = skb->data[0] & LAPB_SPF;
184 frame->control[0] = skb->data[0];
185 frame->control[1] = 0x00;
186 skb_pull(skb, 1);
187 }
188 } else {
189 if (!(skb->data[0] & LAPB_S)) {
190 /*
191 * I frame - carries NR/NS/PF
192 */
193 frame->type = LAPB_I;
194 frame->ns = (skb->data[0] >> 1) & 0x07;
195 frame->nr = (skb->data[0] >> 5) & 0x07;
196 frame->pf = skb->data[0] & LAPB_SPF;
197 } else if ((skb->data[0] & LAPB_U) == 1) {
198 /*
199 * S frame - take out PF/NR
200 */
201 frame->type = skb->data[0] & 0x0F;
202 frame->nr = (skb->data[0] >> 5) & 0x07;
203 frame->pf = skb->data[0] & LAPB_SPF;
204 } else if ((skb->data[0] & LAPB_U) == 3) {
205 /*
206 * U frame - take out PF
207 */
208 frame->type = skb->data[0] & ~LAPB_SPF;
209 frame->pf = skb->data[0] & LAPB_SPF;
210 }
211
212 frame->control[0] = skb->data[0];
213
214 skb_pull(skb, 1);
215 }
216
217 return 0;
218}
219
220/*
221 * This routine is called when the HDLC layer internally generates a
222 * command or response for the remote machine ( eg. RR, UA etc. ).
223 * Only supervisory or unnumbered frames are processed, FRMRs are handled
224 * by lapb_transmit_frmr below.
225 */
226void lapb_send_control(struct lapb_cb *lapb, int frametype,
227 int poll_bit, int type)
228{
229 struct sk_buff *skb;
230 unsigned char *dptr;
231
232 if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL)
233 return;
234
235 skb_reserve(skb, LAPB_HEADER_LEN + 1);
236
237 if (lapb->mode & LAPB_EXTENDED) {
238 if ((frametype & LAPB_U) == LAPB_U) {
239 dptr = skb_put(skb, 1);
240 *dptr = frametype;
241 *dptr |= poll_bit ? LAPB_SPF : 0;
242 } else {
243 dptr = skb_put(skb, 2);
244 dptr[0] = frametype;
245 dptr[1] = (lapb->vr << 1);
246 dptr[1] |= poll_bit ? LAPB_EPF : 0;
247 }
248 } else {
249 dptr = skb_put(skb, 1);
250 *dptr = frametype;
251 *dptr |= poll_bit ? LAPB_SPF : 0;
252 if ((frametype & LAPB_U) == LAPB_S) /* S frames carry NR */
253 *dptr |= (lapb->vr << 5);
254 }
255
256 lapb_transmit_buffer(lapb, skb, type);
257}
258
259/*
260 * This routine generates FRMRs based on information previously stored in
261 * the LAPB control block.
262 */
263void lapb_transmit_frmr(struct lapb_cb *lapb)
264{
265 struct sk_buff *skb;
266 unsigned char *dptr;
267
268 if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL)
269 return;
270
271 skb_reserve(skb, LAPB_HEADER_LEN + 1);
272
273 if (lapb->mode & LAPB_EXTENDED) {
274 dptr = skb_put(skb, 6);
275 *dptr++ = LAPB_FRMR;
276 *dptr++ = lapb->frmr_data.control[0];
277 *dptr++ = lapb->frmr_data.control[1];
278 *dptr++ = (lapb->vs << 1) & 0xFE;
279 *dptr = (lapb->vr << 1) & 0xFE;
280 if (lapb->frmr_data.cr == LAPB_RESPONSE)
281 *dptr |= 0x01;
282 dptr++;
283 *dptr++ = lapb->frmr_type;
284
285 lapb_dbg(1, "(%p) S%d TX FRMR %5ph\n",
286 lapb->dev, lapb->state,
287 &skb->data[1]);
288 } else {
289 dptr = skb_put(skb, 4);
290 *dptr++ = LAPB_FRMR;
291 *dptr++ = lapb->frmr_data.control[0];
292 *dptr = (lapb->vs << 1) & 0x0E;
293 *dptr |= (lapb->vr << 5) & 0xE0;
294 if (lapb->frmr_data.cr == LAPB_RESPONSE)
295 *dptr |= 0x10;
296 dptr++;
297 *dptr++ = lapb->frmr_type;
298
299 lapb_dbg(1, "(%p) S%d TX FRMR %3ph\n",
300 lapb->dev, lapb->state, &skb->data[1]);
301 }
302
303 lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE);
304}