]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | #include <linux/errno.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/socket.h> | |
19 | #include <linux/in.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/timer.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/sockios.h> | |
25 | #include <linux/net.h> | |
26 | #include <linux/inet.h> | |
27 | #include <linux/skbuff.h> | |
28 | #include <net/sock.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include <asm/system.h> | |
31 | #include <linux/fcntl.h> | |
32 | #include <linux/mm.h> | |
33 | #include <linux/interrupt.h> | |
34 | #include <net/lapb.h> | |
35 | ||
36 | /* | |
37 | * This routine purges all the queues of frames. | |
38 | */ | |
39 | void lapb_clear_queues(struct lapb_cb *lapb) | |
40 | { | |
41 | skb_queue_purge(&lapb->write_queue); | |
42 | skb_queue_purge(&lapb->ack_queue); | |
43 | } | |
44 | ||
45 | /* | |
46 | * This routine purges the input queue of those frames that have been | |
47 | * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the | |
48 | * SDL diagram. | |
49 | */ | |
50 | void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr) | |
51 | { | |
52 | struct sk_buff *skb; | |
53 | int modulus; | |
54 | ||
55 | modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; | |
56 | ||
57 | /* | |
58 | * Remove all the ack-ed frames from the ack queue. | |
59 | */ | |
60 | if (lapb->va != nr) | |
61 | while (skb_peek(&lapb->ack_queue) && lapb->va != nr) { | |
62 | skb = skb_dequeue(&lapb->ack_queue); | |
63 | kfree_skb(skb); | |
64 | lapb->va = (lapb->va + 1) % modulus; | |
65 | } | |
66 | } | |
67 | ||
68 | void lapb_requeue_frames(struct lapb_cb *lapb) | |
69 | { | |
70 | struct sk_buff *skb, *skb_prev = NULL; | |
71 | ||
72 | /* | |
73 | * Requeue all the un-ack-ed frames on the output queue to be picked | |
74 | * up by lapb_kick called from the timer. This arrangement handles the | |
75 | * possibility of an empty output queue. | |
76 | */ | |
77 | while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) { | |
78 | if (!skb_prev) | |
79 | skb_queue_head(&lapb->write_queue, skb); | |
80 | else | |
8728b834 | 81 | skb_append(skb_prev, skb, &lapb->write_queue); |
1da177e4 LT |
82 | skb_prev = skb; |
83 | } | |
84 | } | |
85 | ||
86 | /* | |
87 | * Validate that the value of nr is between va and vs. Return true or | |
88 | * false for testing. | |
89 | */ | |
90 | int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr) | |
91 | { | |
92 | unsigned short vc = lapb->va; | |
93 | int modulus; | |
94 | ||
95 | modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; | |
96 | ||
97 | while (vc != lapb->vs) { | |
98 | if (nr == vc) | |
99 | return 1; | |
100 | vc = (vc + 1) % modulus; | |
101 | } | |
102 | ||
103 | return nr == lapb->vs; | |
104 | } | |
105 | ||
106 | /* | |
107 | * This routine is the centralised routine for parsing the control | |
108 | * information for the different frame formats. | |
109 | */ | |
110 | int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb, | |
111 | struct lapb_frame *frame) | |
112 | { | |
113 | frame->type = LAPB_ILLEGAL; | |
114 | ||
115 | #if LAPB_DEBUG > 2 | |
116 | printk(KERN_DEBUG "lapb: (%p) S%d RX %02X %02X %02X\n", | |
117 | lapb->dev, lapb->state, | |
118 | skb->data[0], skb->data[1], skb->data[2]); | |
119 | #endif | |
120 | ||
121 | /* We always need to look at 2 bytes, sometimes we need | |
122 | * to look at 3 and those cases are handled below. | |
123 | */ | |
124 | if (!pskb_may_pull(skb, 2)) | |
125 | return -1; | |
126 | ||
127 | if (lapb->mode & LAPB_MLP) { | |
128 | if (lapb->mode & LAPB_DCE) { | |
129 | if (skb->data[0] == LAPB_ADDR_D) | |
130 | frame->cr = LAPB_COMMAND; | |
131 | if (skb->data[0] == LAPB_ADDR_C) | |
132 | frame->cr = LAPB_RESPONSE; | |
133 | } else { | |
134 | if (skb->data[0] == LAPB_ADDR_C) | |
135 | frame->cr = LAPB_COMMAND; | |
136 | if (skb->data[0] == LAPB_ADDR_D) | |
137 | frame->cr = LAPB_RESPONSE; | |
138 | } | |
139 | } else { | |
140 | if (lapb->mode & LAPB_DCE) { | |
141 | if (skb->data[0] == LAPB_ADDR_B) | |
142 | frame->cr = LAPB_COMMAND; | |
143 | if (skb->data[0] == LAPB_ADDR_A) | |
144 | frame->cr = LAPB_RESPONSE; | |
145 | } else { | |
146 | if (skb->data[0] == LAPB_ADDR_A) | |
147 | frame->cr = LAPB_COMMAND; | |
148 | if (skb->data[0] == LAPB_ADDR_B) | |
149 | frame->cr = LAPB_RESPONSE; | |
150 | } | |
151 | } | |
152 | ||
153 | skb_pull(skb, 1); | |
154 | ||
155 | if (lapb->mode & LAPB_EXTENDED) { | |
156 | if (!(skb->data[0] & LAPB_S)) { | |
157 | if (!pskb_may_pull(skb, 2)) | |
158 | return -1; | |
159 | /* | |
160 | * I frame - carries NR/NS/PF | |
161 | */ | |
162 | frame->type = LAPB_I; | |
163 | frame->ns = (skb->data[0] >> 1) & 0x7F; | |
164 | frame->nr = (skb->data[1] >> 1) & 0x7F; | |
165 | frame->pf = skb->data[1] & LAPB_EPF; | |
166 | frame->control[0] = skb->data[0]; | |
167 | frame->control[1] = skb->data[1]; | |
168 | skb_pull(skb, 2); | |
169 | } else if ((skb->data[0] & LAPB_U) == 1) { | |
170 | if (!pskb_may_pull(skb, 2)) | |
171 | return -1; | |
172 | /* | |
173 | * S frame - take out PF/NR | |
174 | */ | |
175 | frame->type = skb->data[0] & 0x0F; | |
176 | frame->nr = (skb->data[1] >> 1) & 0x7F; | |
177 | frame->pf = skb->data[1] & LAPB_EPF; | |
178 | frame->control[0] = skb->data[0]; | |
179 | frame->control[1] = skb->data[1]; | |
180 | skb_pull(skb, 2); | |
181 | } else if ((skb->data[0] & LAPB_U) == 3) { | |
182 | /* | |
183 | * U frame - take out PF | |
184 | */ | |
185 | frame->type = skb->data[0] & ~LAPB_SPF; | |
186 | frame->pf = skb->data[0] & LAPB_SPF; | |
187 | frame->control[0] = skb->data[0]; | |
188 | frame->control[1] = 0x00; | |
189 | skb_pull(skb, 1); | |
190 | } | |
191 | } else { | |
192 | if (!(skb->data[0] & LAPB_S)) { | |
193 | /* | |
194 | * I frame - carries NR/NS/PF | |
195 | */ | |
196 | frame->type = LAPB_I; | |
197 | frame->ns = (skb->data[0] >> 1) & 0x07; | |
198 | frame->nr = (skb->data[0] >> 5) & 0x07; | |
199 | frame->pf = skb->data[0] & LAPB_SPF; | |
200 | } else if ((skb->data[0] & LAPB_U) == 1) { | |
201 | /* | |
202 | * S frame - take out PF/NR | |
203 | */ | |
204 | frame->type = skb->data[0] & 0x0F; | |
205 | frame->nr = (skb->data[0] >> 5) & 0x07; | |
206 | frame->pf = skb->data[0] & LAPB_SPF; | |
207 | } else if ((skb->data[0] & LAPB_U) == 3) { | |
208 | /* | |
209 | * U frame - take out PF | |
210 | */ | |
211 | frame->type = skb->data[0] & ~LAPB_SPF; | |
212 | frame->pf = skb->data[0] & LAPB_SPF; | |
213 | } | |
214 | ||
215 | frame->control[0] = skb->data[0]; | |
216 | ||
217 | skb_pull(skb, 1); | |
218 | } | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | /* | |
224 | * This routine is called when the HDLC layer internally generates a | |
225 | * command or response for the remote machine ( eg. RR, UA etc. ). | |
226 | * Only supervisory or unnumbered frames are processed, FRMRs are handled | |
227 | * by lapb_transmit_frmr below. | |
228 | */ | |
229 | void lapb_send_control(struct lapb_cb *lapb, int frametype, | |
230 | int poll_bit, int type) | |
231 | { | |
232 | struct sk_buff *skb; | |
233 | unsigned char *dptr; | |
234 | ||
235 | if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL) | |
236 | return; | |
237 | ||
238 | skb_reserve(skb, LAPB_HEADER_LEN + 1); | |
239 | ||
240 | if (lapb->mode & LAPB_EXTENDED) { | |
241 | if ((frametype & LAPB_U) == LAPB_U) { | |
242 | dptr = skb_put(skb, 1); | |
243 | *dptr = frametype; | |
244 | *dptr |= poll_bit ? LAPB_SPF : 0; | |
245 | } else { | |
246 | dptr = skb_put(skb, 2); | |
247 | dptr[0] = frametype; | |
248 | dptr[1] = (lapb->vr << 1); | |
249 | dptr[1] |= poll_bit ? LAPB_EPF : 0; | |
250 | } | |
251 | } else { | |
252 | dptr = skb_put(skb, 1); | |
253 | *dptr = frametype; | |
254 | *dptr |= poll_bit ? LAPB_SPF : 0; | |
255 | if ((frametype & LAPB_U) == LAPB_S) /* S frames carry NR */ | |
256 | *dptr |= (lapb->vr << 5); | |
257 | } | |
258 | ||
259 | lapb_transmit_buffer(lapb, skb, type); | |
260 | } | |
261 | ||
262 | /* | |
263 | * This routine generates FRMRs based on information previously stored in | |
264 | * the LAPB control block. | |
265 | */ | |
266 | void lapb_transmit_frmr(struct lapb_cb *lapb) | |
267 | { | |
268 | struct sk_buff *skb; | |
269 | unsigned char *dptr; | |
270 | ||
271 | if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL) | |
272 | return; | |
273 | ||
274 | skb_reserve(skb, LAPB_HEADER_LEN + 1); | |
275 | ||
276 | if (lapb->mode & LAPB_EXTENDED) { | |
277 | dptr = skb_put(skb, 6); | |
278 | *dptr++ = LAPB_FRMR; | |
279 | *dptr++ = lapb->frmr_data.control[0]; | |
280 | *dptr++ = lapb->frmr_data.control[1]; | |
281 | *dptr++ = (lapb->vs << 1) & 0xFE; | |
282 | *dptr = (lapb->vr << 1) & 0xFE; | |
283 | if (lapb->frmr_data.cr == LAPB_RESPONSE) | |
284 | *dptr |= 0x01; | |
285 | dptr++; | |
286 | *dptr++ = lapb->frmr_type; | |
287 | ||
288 | #if LAPB_DEBUG > 1 | |
289 | printk(KERN_DEBUG "lapb: (%p) S%d TX FRMR %02X %02X %02X %02X %02X\n", | |
290 | lapb->dev, lapb->state, | |
291 | skb->data[1], skb->data[2], skb->data[3], | |
292 | skb->data[4], skb->data[5]); | |
293 | #endif | |
294 | } else { | |
295 | dptr = skb_put(skb, 4); | |
296 | *dptr++ = LAPB_FRMR; | |
297 | *dptr++ = lapb->frmr_data.control[0]; | |
298 | *dptr = (lapb->vs << 1) & 0x0E; | |
299 | *dptr |= (lapb->vr << 5) & 0xE0; | |
300 | if (lapb->frmr_data.cr == LAPB_RESPONSE) | |
301 | *dptr |= 0x10; | |
302 | dptr++; | |
303 | *dptr++ = lapb->frmr_type; | |
304 | ||
305 | #if LAPB_DEBUG > 1 | |
306 | printk(KERN_DEBUG "lapb: (%p) S%d TX FRMR %02X %02X %02X\n", | |
307 | lapb->dev, lapb->state, skb->data[1], | |
308 | skb->data[2], skb->data[3]); | |
309 | #endif | |
310 | } | |
311 | ||
312 | lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE); | |
313 | } |