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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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
11 */
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/in.h>
16#include <linux/kernel.h>
17#include <linux/timer.h>
18#include <linux/string.h>
19#include <linux/sockios.h>
20#include <linux/net.h>
21#include <linux/slab.h>
22#include <net/ax25.h>
23#include <linux/inet.h>
24#include <linux/netdevice.h>
25#include <linux/skbuff.h>
26#include <net/sock.h>
27#include <net/tcp_states.h>
28#include <asm/uaccess.h>
29#include <asm/system.h>
30#include <linux/fcntl.h>
31#include <linux/mm.h>
32#include <linux/interrupt.h>
33
34/*
35 * This routine purges all the queues of frames.
36 */
37void ax25_clear_queues(ax25_cb *ax25)
38{
39 skb_queue_purge(&ax25->write_queue);
40 skb_queue_purge(&ax25->ack_queue);
41 skb_queue_purge(&ax25->reseq_queue);
42 skb_queue_purge(&ax25->frag_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 */
50void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)
51{
52 struct sk_buff *skb;
53
54 /*
55 * Remove all the ack-ed frames from the ack queue.
56 */
57 if (ax25->va != nr) {
58 while (skb_peek(&ax25->ack_queue) != NULL && ax25->va != nr) {
59 skb = skb_dequeue(&ax25->ack_queue);
60 kfree_skb(skb);
61 ax25->va = (ax25->va + 1) % ax25->modulus;
62 }
63 }
64}
65
66void ax25_requeue_frames(ax25_cb *ax25)
67{
68 struct sk_buff *skb;
69
70 /*
71 * Requeue all the un-ack-ed frames on the output queue to be picked
72 * up by ax25_kick called from the timer. This arrangement handles the
73 * possibility of an empty output queue.
74 */
75 while ((skb = skb_dequeue_tail(&ax25->ack_queue)) != NULL)
76 skb_queue_head(&ax25->write_queue, skb);
77}
78
79/*
80 * Validate that the value of nr is between va and vs. Return true or
81 * false for testing.
82 */
83int ax25_validate_nr(ax25_cb *ax25, unsigned short nr)
84{
85 unsigned short vc = ax25->va;
86
87 while (vc != ax25->vs) {
88 if (nr == vc) return 1;
89 vc = (vc + 1) % ax25->modulus;
90 }
91
92 if (nr == ax25->vs) return 1;
93
94 return 0;
95}
96
97/*
98 * This routine is the centralised routine for parsing the control
99 * information for the different frame formats.
100 */
101int ax25_decode(ax25_cb *ax25, struct sk_buff *skb, int *ns, int *nr, int *pf)
102{
103 unsigned char *frame;
104 int frametype = AX25_ILLEGAL;
105
106 frame = skb->data;
107 *ns = *nr = *pf = 0;
108
109 if (ax25->modulus == AX25_MODULUS) {
110 if ((frame[0] & AX25_S) == 0) {
111 frametype = AX25_I; /* I frame - carries NR/NS/PF */
112 *ns = (frame[0] >> 1) & 0x07;
113 *nr = (frame[0] >> 5) & 0x07;
114 *pf = frame[0] & AX25_PF;
115 } else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */
116 frametype = frame[0] & 0x0F;
117 *nr = (frame[0] >> 5) & 0x07;
118 *pf = frame[0] & AX25_PF;
119 } else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */
120 frametype = frame[0] & ~AX25_PF;
121 *pf = frame[0] & AX25_PF;
122 }
123 skb_pull(skb, 1);
124 } else {
125 if ((frame[0] & AX25_S) == 0) {
126 frametype = AX25_I; /* I frame - carries NR/NS/PF */
127 *ns = (frame[0] >> 1) & 0x7F;
128 *nr = (frame[1] >> 1) & 0x7F;
129 *pf = frame[1] & AX25_EPF;
130 skb_pull(skb, 2);
131 } else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */
132 frametype = frame[0] & 0x0F;
133 *nr = (frame[1] >> 1) & 0x7F;
134 *pf = frame[1] & AX25_EPF;
135 skb_pull(skb, 2);
136 } else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */
137 frametype = frame[0] & ~AX25_PF;
138 *pf = frame[0] & AX25_PF;
139 skb_pull(skb, 1);
140 }
141 }
142
143 return frametype;
144}
145
146/*
147 * This routine is called when the HDLC layer internally generates a
148 * command or response for the remote machine ( eg. RR, UA etc. ).
149 * Only supervisory or unnumbered frames are processed.
150 */
151void ax25_send_control(ax25_cb *ax25, int frametype, int poll_bit, int type)
152{
153 struct sk_buff *skb;
154 unsigned char *dptr;
155
156 if ((skb = alloc_skb(ax25->ax25_dev->dev->hard_header_len + 2, GFP_ATOMIC)) == NULL)
157 return;
158
159 skb_reserve(skb, ax25->ax25_dev->dev->hard_header_len);
160
161 skb_reset_network_header(skb);
162
163 /* Assume a response - address structure for DTE */
164 if (ax25->modulus == AX25_MODULUS) {
165 dptr = skb_put(skb, 1);
166 *dptr = frametype;
167 *dptr |= (poll_bit) ? AX25_PF : 0;
168 if ((frametype & AX25_U) == AX25_S) /* S frames carry NR */
169 *dptr |= (ax25->vr << 5);
170 } else {
171 if ((frametype & AX25_U) == AX25_U) {
172 dptr = skb_put(skb, 1);
173 *dptr = frametype;
174 *dptr |= (poll_bit) ? AX25_PF : 0;
175 } else {
176 dptr = skb_put(skb, 2);
177 dptr[0] = frametype;
178 dptr[1] = (ax25->vr << 1);
179 dptr[1] |= (poll_bit) ? AX25_EPF : 0;
180 }
181 }
182
183 ax25_transmit_buffer(ax25, skb, type);
184}
185
186/*
187 * Send a 'DM' to an unknown connection attempt, or an invalid caller.
188 *
189 * Note: src here is the sender, thus it's the target of the DM
190 */
191void ax25_return_dm(struct net_device *dev, ax25_address *src, ax25_address *dest, ax25_digi *digi)
192{
193 struct sk_buff *skb;
194 char *dptr;
195 ax25_digi retdigi;
196
197 if (dev == NULL)
198 return;
199
200 if ((skb = alloc_skb(dev->hard_header_len + 1, GFP_ATOMIC)) == NULL)
201 return; /* Next SABM will get DM'd */
202
203 skb_reserve(skb, dev->hard_header_len);
204 skb_reset_network_header(skb);
205
206 ax25_digi_invert(digi, &retdigi);
207
208 dptr = skb_put(skb, 1);
209
210 *dptr = AX25_DM | AX25_PF;
211
212 /*
213 * Do the address ourselves
214 */
215 dptr = skb_push(skb, ax25_addr_size(digi));
216 dptr += ax25_addr_build(dptr, dest, src, &retdigi, AX25_RESPONSE, AX25_MODULUS);
217
218 ax25_queue_xmit(skb, dev);
219}
220
221/*
222 * Exponential backoff for AX.25
223 */
224void ax25_calculate_t1(ax25_cb *ax25)
225{
226 int n, t = 2;
227
228 switch (ax25->backoff) {
229 case 0:
230 break;
231
232 case 1:
233 t += 2 * ax25->n2count;
234 break;
235
236 case 2:
237 for (n = 0; n < ax25->n2count; n++)
238 t *= 2;
239 if (t > 8) t = 8;
240 break;
241 }
242
243 ax25->t1 = t * ax25->rtt;
244}
245
246/*
247 * Calculate the Round Trip Time
248 */
249void ax25_calculate_rtt(ax25_cb *ax25)
250{
251 if (ax25->backoff == 0)
252 return;
253
254 if (ax25_t1timer_running(ax25) && ax25->n2count == 0)
255 ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10;
256
257 if (ax25->rtt < AX25_T1CLAMPLO)
258 ax25->rtt = AX25_T1CLAMPLO;
259
260 if (ax25->rtt > AX25_T1CLAMPHI)
261 ax25->rtt = AX25_T1CLAMPHI;
262}
263
264void ax25_disconnect(ax25_cb *ax25, int reason)
265{
266 ax25_clear_queues(ax25);
267
268 ax25_stop_t1timer(ax25);
269 ax25_stop_t2timer(ax25);
270 ax25_stop_t3timer(ax25);
271 ax25_stop_idletimer(ax25);
272
273 ax25->state = AX25_STATE_0;
274
275 ax25_link_failed(ax25, reason);
276
277 if (ax25->sk != NULL) {
278 local_bh_disable();
279 bh_lock_sock(ax25->sk);
280 ax25->sk->sk_state = TCP_CLOSE;
281 ax25->sk->sk_err = reason;
282 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
283 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
284 ax25->sk->sk_state_change(ax25->sk);
285 sock_set_flag(ax25->sk, SOCK_DEAD);
286 }
287 bh_unlock_sock(ax25->sk);
288 local_bh_enable();
289 }
290}
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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
11 */
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/in.h>
16#include <linux/kernel.h>
17#include <linux/timer.h>
18#include <linux/string.h>
19#include <linux/sockios.h>
20#include <linux/net.h>
21#include <linux/slab.h>
22#include <net/ax25.h>
23#include <linux/inet.h>
24#include <linux/netdevice.h>
25#include <linux/skbuff.h>
26#include <net/sock.h>
27#include <net/tcp_states.h>
28#include <asm/uaccess.h>
29#include <linux/fcntl.h>
30#include <linux/mm.h>
31#include <linux/interrupt.h>
32
33/*
34 * This routine purges all the queues of frames.
35 */
36void ax25_clear_queues(ax25_cb *ax25)
37{
38 skb_queue_purge(&ax25->write_queue);
39 skb_queue_purge(&ax25->ack_queue);
40 skb_queue_purge(&ax25->reseq_queue);
41 skb_queue_purge(&ax25->frag_queue);
42}
43
44/*
45 * This routine purges the input queue of those frames that have been
46 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
47 * SDL diagram.
48 */
49void ax25_frames_acked(ax25_cb *ax25, unsigned short nr)
50{
51 struct sk_buff *skb;
52
53 /*
54 * Remove all the ack-ed frames from the ack queue.
55 */
56 if (ax25->va != nr) {
57 while (skb_peek(&ax25->ack_queue) != NULL && ax25->va != nr) {
58 skb = skb_dequeue(&ax25->ack_queue);
59 kfree_skb(skb);
60 ax25->va = (ax25->va + 1) % ax25->modulus;
61 }
62 }
63}
64
65void ax25_requeue_frames(ax25_cb *ax25)
66{
67 struct sk_buff *skb;
68
69 /*
70 * Requeue all the un-ack-ed frames on the output queue to be picked
71 * up by ax25_kick called from the timer. This arrangement handles the
72 * possibility of an empty output queue.
73 */
74 while ((skb = skb_dequeue_tail(&ax25->ack_queue)) != NULL)
75 skb_queue_head(&ax25->write_queue, skb);
76}
77
78/*
79 * Validate that the value of nr is between va and vs. Return true or
80 * false for testing.
81 */
82int ax25_validate_nr(ax25_cb *ax25, unsigned short nr)
83{
84 unsigned short vc = ax25->va;
85
86 while (vc != ax25->vs) {
87 if (nr == vc) return 1;
88 vc = (vc + 1) % ax25->modulus;
89 }
90
91 if (nr == ax25->vs) return 1;
92
93 return 0;
94}
95
96/*
97 * This routine is the centralised routine for parsing the control
98 * information for the different frame formats.
99 */
100int ax25_decode(ax25_cb *ax25, struct sk_buff *skb, int *ns, int *nr, int *pf)
101{
102 unsigned char *frame;
103 int frametype = AX25_ILLEGAL;
104
105 frame = skb->data;
106 *ns = *nr = *pf = 0;
107
108 if (ax25->modulus == AX25_MODULUS) {
109 if ((frame[0] & AX25_S) == 0) {
110 frametype = AX25_I; /* I frame - carries NR/NS/PF */
111 *ns = (frame[0] >> 1) & 0x07;
112 *nr = (frame[0] >> 5) & 0x07;
113 *pf = frame[0] & AX25_PF;
114 } else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */
115 frametype = frame[0] & 0x0F;
116 *nr = (frame[0] >> 5) & 0x07;
117 *pf = frame[0] & AX25_PF;
118 } else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */
119 frametype = frame[0] & ~AX25_PF;
120 *pf = frame[0] & AX25_PF;
121 }
122 skb_pull(skb, 1);
123 } else {
124 if ((frame[0] & AX25_S) == 0) {
125 frametype = AX25_I; /* I frame - carries NR/NS/PF */
126 *ns = (frame[0] >> 1) & 0x7F;
127 *nr = (frame[1] >> 1) & 0x7F;
128 *pf = frame[1] & AX25_EPF;
129 skb_pull(skb, 2);
130 } else if ((frame[0] & AX25_U) == 1) { /* S frame - take out PF/NR */
131 frametype = frame[0] & 0x0F;
132 *nr = (frame[1] >> 1) & 0x7F;
133 *pf = frame[1] & AX25_EPF;
134 skb_pull(skb, 2);
135 } else if ((frame[0] & AX25_U) == 3) { /* U frame - take out PF */
136 frametype = frame[0] & ~AX25_PF;
137 *pf = frame[0] & AX25_PF;
138 skb_pull(skb, 1);
139 }
140 }
141
142 return frametype;
143}
144
145/*
146 * This routine is called when the HDLC layer internally generates a
147 * command or response for the remote machine ( eg. RR, UA etc. ).
148 * Only supervisory or unnumbered frames are processed.
149 */
150void ax25_send_control(ax25_cb *ax25, int frametype, int poll_bit, int type)
151{
152 struct sk_buff *skb;
153 unsigned char *dptr;
154
155 if ((skb = alloc_skb(ax25->ax25_dev->dev->hard_header_len + 2, GFP_ATOMIC)) == NULL)
156 return;
157
158 skb_reserve(skb, ax25->ax25_dev->dev->hard_header_len);
159
160 skb_reset_network_header(skb);
161
162 /* Assume a response - address structure for DTE */
163 if (ax25->modulus == AX25_MODULUS) {
164 dptr = skb_put(skb, 1);
165 *dptr = frametype;
166 *dptr |= (poll_bit) ? AX25_PF : 0;
167 if ((frametype & AX25_U) == AX25_S) /* S frames carry NR */
168 *dptr |= (ax25->vr << 5);
169 } else {
170 if ((frametype & AX25_U) == AX25_U) {
171 dptr = skb_put(skb, 1);
172 *dptr = frametype;
173 *dptr |= (poll_bit) ? AX25_PF : 0;
174 } else {
175 dptr = skb_put(skb, 2);
176 dptr[0] = frametype;
177 dptr[1] = (ax25->vr << 1);
178 dptr[1] |= (poll_bit) ? AX25_EPF : 0;
179 }
180 }
181
182 ax25_transmit_buffer(ax25, skb, type);
183}
184
185/*
186 * Send a 'DM' to an unknown connection attempt, or an invalid caller.
187 *
188 * Note: src here is the sender, thus it's the target of the DM
189 */
190void ax25_return_dm(struct net_device *dev, ax25_address *src, ax25_address *dest, ax25_digi *digi)
191{
192 struct sk_buff *skb;
193 char *dptr;
194 ax25_digi retdigi;
195
196 if (dev == NULL)
197 return;
198
199 if ((skb = alloc_skb(dev->hard_header_len + 1, GFP_ATOMIC)) == NULL)
200 return; /* Next SABM will get DM'd */
201
202 skb_reserve(skb, dev->hard_header_len);
203 skb_reset_network_header(skb);
204
205 ax25_digi_invert(digi, &retdigi);
206
207 dptr = skb_put(skb, 1);
208
209 *dptr = AX25_DM | AX25_PF;
210
211 /*
212 * Do the address ourselves
213 */
214 dptr = skb_push(skb, ax25_addr_size(digi));
215 dptr += ax25_addr_build(dptr, dest, src, &retdigi, AX25_RESPONSE, AX25_MODULUS);
216
217 ax25_queue_xmit(skb, dev);
218}
219
220/*
221 * Exponential backoff for AX.25
222 */
223void ax25_calculate_t1(ax25_cb *ax25)
224{
225 int n, t = 2;
226
227 switch (ax25->backoff) {
228 case 0:
229 break;
230
231 case 1:
232 t += 2 * ax25->n2count;
233 break;
234
235 case 2:
236 for (n = 0; n < ax25->n2count; n++)
237 t *= 2;
238 if (t > 8) t = 8;
239 break;
240 }
241
242 ax25->t1 = t * ax25->rtt;
243}
244
245/*
246 * Calculate the Round Trip Time
247 */
248void ax25_calculate_rtt(ax25_cb *ax25)
249{
250 if (ax25->backoff == 0)
251 return;
252
253 if (ax25_t1timer_running(ax25) && ax25->n2count == 0)
254 ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10;
255
256 if (ax25->rtt < AX25_T1CLAMPLO)
257 ax25->rtt = AX25_T1CLAMPLO;
258
259 if (ax25->rtt > AX25_T1CLAMPHI)
260 ax25->rtt = AX25_T1CLAMPHI;
261}
262
263void ax25_disconnect(ax25_cb *ax25, int reason)
264{
265 ax25_clear_queues(ax25);
266
267 ax25_stop_t1timer(ax25);
268 ax25_stop_t2timer(ax25);
269 ax25_stop_t3timer(ax25);
270 ax25_stop_idletimer(ax25);
271
272 ax25->state = AX25_STATE_0;
273
274 ax25_link_failed(ax25, reason);
275
276 if (ax25->sk != NULL) {
277 local_bh_disable();
278 bh_lock_sock(ax25->sk);
279 ax25->sk->sk_state = TCP_CLOSE;
280 ax25->sk->sk_err = reason;
281 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
282 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
283 ax25->sk->sk_state_change(ax25->sk);
284 sock_set_flag(ax25->sk, SOCK_DEAD);
285 }
286 bh_unlock_sock(ax25->sk);
287 local_bh_enable();
288 }
289}