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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 *
6 * Most of this code is based on the SDL diagrams published in the 7th ARRL
7 * Computer Networking Conference papers. The diagrams have mistakes in them,
8 * but are mostly correct. Before you modify the code could you read the SDL
9 * diagrams as the code is not obvious and probably very easy to break.
10 */
11#include <linux/errno.h>
12#include <linux/filter.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 <net/ax25.h>
22#include <linux/inet.h>
23#include <linux/netdevice.h>
24#include <linux/skbuff.h>
25#include <net/sock.h>
26#include <net/tcp_states.h>
27#include <linux/fcntl.h>
28#include <linux/mm.h>
29#include <linux/interrupt.h>
30#include <net/rose.h>
31
32/*
33 * State machine for state 1, Awaiting Call Accepted State.
34 * The handling of the timer(s) is in file rose_timer.c.
35 * Handling of state 0 and connection release is in af_rose.c.
36 */
37static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
38{
39 struct rose_sock *rose = rose_sk(sk);
40
41 switch (frametype) {
42 case ROSE_CALL_ACCEPTED:
43 rose_stop_timer(sk);
44 rose_start_idletimer(sk);
45 rose->condition = 0x00;
46 rose->vs = 0;
47 rose->va = 0;
48 rose->vr = 0;
49 rose->vl = 0;
50 rose->state = ROSE_STATE_3;
51 sk->sk_state = TCP_ESTABLISHED;
52 if (!sock_flag(sk, SOCK_DEAD))
53 sk->sk_state_change(sk);
54 break;
55
56 case ROSE_CLEAR_REQUEST:
57 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
58 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
59 rose->neighbour->use--;
60 break;
61
62 default:
63 break;
64 }
65
66 return 0;
67}
68
69/*
70 * State machine for state 2, Awaiting Clear Confirmation State.
71 * The handling of the timer(s) is in file rose_timer.c
72 * Handling of state 0 and connection release is in af_rose.c.
73 */
74static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
75{
76 struct rose_sock *rose = rose_sk(sk);
77
78 switch (frametype) {
79 case ROSE_CLEAR_REQUEST:
80 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
81 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
82 rose->neighbour->use--;
83 break;
84
85 case ROSE_CLEAR_CONFIRMATION:
86 rose_disconnect(sk, 0, -1, -1);
87 rose->neighbour->use--;
88 break;
89
90 default:
91 break;
92 }
93
94 return 0;
95}
96
97/*
98 * State machine for state 3, Connected State.
99 * The handling of the timer(s) is in file rose_timer.c
100 * Handling of state 0 and connection release is in af_rose.c.
101 */
102static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
103{
104 struct rose_sock *rose = rose_sk(sk);
105 int queued = 0;
106
107 switch (frametype) {
108 case ROSE_RESET_REQUEST:
109 rose_stop_timer(sk);
110 rose_start_idletimer(sk);
111 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
112 rose->condition = 0x00;
113 rose->vs = 0;
114 rose->vr = 0;
115 rose->va = 0;
116 rose->vl = 0;
117 rose_requeue_frames(sk);
118 break;
119
120 case ROSE_CLEAR_REQUEST:
121 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
122 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
123 rose->neighbour->use--;
124 break;
125
126 case ROSE_RR:
127 case ROSE_RNR:
128 if (!rose_validate_nr(sk, nr)) {
129 rose_write_internal(sk, ROSE_RESET_REQUEST);
130 rose->condition = 0x00;
131 rose->vs = 0;
132 rose->vr = 0;
133 rose->va = 0;
134 rose->vl = 0;
135 rose->state = ROSE_STATE_4;
136 rose_start_t2timer(sk);
137 rose_stop_idletimer(sk);
138 } else {
139 rose_frames_acked(sk, nr);
140 if (frametype == ROSE_RNR) {
141 rose->condition |= ROSE_COND_PEER_RX_BUSY;
142 } else {
143 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
144 }
145 }
146 break;
147
148 case ROSE_DATA: /* XXX */
149 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
150 if (!rose_validate_nr(sk, nr)) {
151 rose_write_internal(sk, ROSE_RESET_REQUEST);
152 rose->condition = 0x00;
153 rose->vs = 0;
154 rose->vr = 0;
155 rose->va = 0;
156 rose->vl = 0;
157 rose->state = ROSE_STATE_4;
158 rose_start_t2timer(sk);
159 rose_stop_idletimer(sk);
160 break;
161 }
162 rose_frames_acked(sk, nr);
163 if (ns == rose->vr) {
164 rose_start_idletimer(sk);
165 if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
166 __sock_queue_rcv_skb(sk, skb) == 0) {
167 rose->vr = (rose->vr + 1) % ROSE_MODULUS;
168 queued = 1;
169 } else {
170 /* Should never happen ! */
171 rose_write_internal(sk, ROSE_RESET_REQUEST);
172 rose->condition = 0x00;
173 rose->vs = 0;
174 rose->vr = 0;
175 rose->va = 0;
176 rose->vl = 0;
177 rose->state = ROSE_STATE_4;
178 rose_start_t2timer(sk);
179 rose_stop_idletimer(sk);
180 break;
181 }
182 if (atomic_read(&sk->sk_rmem_alloc) >
183 (sk->sk_rcvbuf >> 1))
184 rose->condition |= ROSE_COND_OWN_RX_BUSY;
185 }
186 /*
187 * If the window is full, ack the frame, else start the
188 * acknowledge hold back timer.
189 */
190 if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
191 rose->condition &= ~ROSE_COND_ACK_PENDING;
192 rose_stop_timer(sk);
193 rose_enquiry_response(sk);
194 } else {
195 rose->condition |= ROSE_COND_ACK_PENDING;
196 rose_start_hbtimer(sk);
197 }
198 break;
199
200 default:
201 printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
202 break;
203 }
204
205 return queued;
206}
207
208/*
209 * State machine for state 4, Awaiting Reset Confirmation State.
210 * The handling of the timer(s) is in file rose_timer.c
211 * Handling of state 0 and connection release is in af_rose.c.
212 */
213static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
214{
215 struct rose_sock *rose = rose_sk(sk);
216
217 switch (frametype) {
218 case ROSE_RESET_REQUEST:
219 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
220 fallthrough;
221 case ROSE_RESET_CONFIRMATION:
222 rose_stop_timer(sk);
223 rose_start_idletimer(sk);
224 rose->condition = 0x00;
225 rose->va = 0;
226 rose->vr = 0;
227 rose->vs = 0;
228 rose->vl = 0;
229 rose->state = ROSE_STATE_3;
230 rose_requeue_frames(sk);
231 break;
232
233 case ROSE_CLEAR_REQUEST:
234 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
235 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
236 rose->neighbour->use--;
237 break;
238
239 default:
240 break;
241 }
242
243 return 0;
244}
245
246/*
247 * State machine for state 5, Awaiting Call Acceptance State.
248 * The handling of the timer(s) is in file rose_timer.c
249 * Handling of state 0 and connection release is in af_rose.c.
250 */
251static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
252{
253 if (frametype == ROSE_CLEAR_REQUEST) {
254 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
255 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
256 rose_sk(sk)->neighbour->use--;
257 }
258
259 return 0;
260}
261
262/* Higher level upcall for a LAPB frame */
263int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
264{
265 struct rose_sock *rose = rose_sk(sk);
266 int queued = 0, frametype, ns, nr, q, d, m;
267
268 if (rose->state == ROSE_STATE_0)
269 return 0;
270
271 frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
272
273 switch (rose->state) {
274 case ROSE_STATE_1:
275 queued = rose_state1_machine(sk, skb, frametype);
276 break;
277 case ROSE_STATE_2:
278 queued = rose_state2_machine(sk, skb, frametype);
279 break;
280 case ROSE_STATE_3:
281 queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
282 break;
283 case ROSE_STATE_4:
284 queued = rose_state4_machine(sk, skb, frametype);
285 break;
286 case ROSE_STATE_5:
287 queued = rose_state5_machine(sk, skb, frametype);
288 break;
289 }
290
291 rose_kick(sk);
292
293 return queued;
294}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 *
6 * Most of this code is based on the SDL diagrams published in the 7th ARRL
7 * Computer Networking Conference papers. The diagrams have mistakes in them,
8 * but are mostly correct. Before you modify the code could you read the SDL
9 * diagrams as the code is not obvious and probably very easy to break.
10 */
11#include <linux/errno.h>
12#include <linux/filter.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 <net/ax25.h>
22#include <linux/inet.h>
23#include <linux/netdevice.h>
24#include <linux/skbuff.h>
25#include <net/sock.h>
26#include <net/tcp_states.h>
27#include <linux/fcntl.h>
28#include <linux/mm.h>
29#include <linux/interrupt.h>
30#include <net/rose.h>
31
32/*
33 * State machine for state 1, Awaiting Call Accepted State.
34 * The handling of the timer(s) is in file rose_timer.c.
35 * Handling of state 0 and connection release is in af_rose.c.
36 */
37static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
38{
39 struct rose_sock *rose = rose_sk(sk);
40
41 switch (frametype) {
42 case ROSE_CALL_ACCEPTED:
43 rose_stop_timer(sk);
44 rose_start_idletimer(sk);
45 rose->condition = 0x00;
46 rose->vs = 0;
47 rose->va = 0;
48 rose->vr = 0;
49 rose->vl = 0;
50 rose->state = ROSE_STATE_3;
51 sk->sk_state = TCP_ESTABLISHED;
52 if (!sock_flag(sk, SOCK_DEAD))
53 sk->sk_state_change(sk);
54 break;
55
56 case ROSE_CLEAR_REQUEST:
57 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
58 rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
59 rose->neighbour->use--;
60 break;
61
62 default:
63 break;
64 }
65
66 return 0;
67}
68
69/*
70 * State machine for state 2, Awaiting Clear Confirmation State.
71 * The handling of the timer(s) is in file rose_timer.c
72 * Handling of state 0 and connection release is in af_rose.c.
73 */
74static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
75{
76 struct rose_sock *rose = rose_sk(sk);
77
78 switch (frametype) {
79 case ROSE_CLEAR_REQUEST:
80 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
81 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
82 rose->neighbour->use--;
83 break;
84
85 case ROSE_CLEAR_CONFIRMATION:
86 rose_disconnect(sk, 0, -1, -1);
87 rose->neighbour->use--;
88 break;
89
90 default:
91 break;
92 }
93
94 return 0;
95}
96
97/*
98 * State machine for state 3, Connected State.
99 * The handling of the timer(s) is in file rose_timer.c
100 * Handling of state 0 and connection release is in af_rose.c.
101 */
102static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
103{
104 struct rose_sock *rose = rose_sk(sk);
105 int queued = 0;
106
107 switch (frametype) {
108 case ROSE_RESET_REQUEST:
109 rose_stop_timer(sk);
110 rose_start_idletimer(sk);
111 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
112 rose->condition = 0x00;
113 rose->vs = 0;
114 rose->vr = 0;
115 rose->va = 0;
116 rose->vl = 0;
117 rose_requeue_frames(sk);
118 break;
119
120 case ROSE_CLEAR_REQUEST:
121 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
122 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
123 rose->neighbour->use--;
124 break;
125
126 case ROSE_RR:
127 case ROSE_RNR:
128 if (!rose_validate_nr(sk, nr)) {
129 rose_write_internal(sk, ROSE_RESET_REQUEST);
130 rose->condition = 0x00;
131 rose->vs = 0;
132 rose->vr = 0;
133 rose->va = 0;
134 rose->vl = 0;
135 rose->state = ROSE_STATE_4;
136 rose_start_t2timer(sk);
137 rose_stop_idletimer(sk);
138 } else {
139 rose_frames_acked(sk, nr);
140 if (frametype == ROSE_RNR) {
141 rose->condition |= ROSE_COND_PEER_RX_BUSY;
142 } else {
143 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
144 }
145 }
146 break;
147
148 case ROSE_DATA: /* XXX */
149 rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
150 if (!rose_validate_nr(sk, nr)) {
151 rose_write_internal(sk, ROSE_RESET_REQUEST);
152 rose->condition = 0x00;
153 rose->vs = 0;
154 rose->vr = 0;
155 rose->va = 0;
156 rose->vl = 0;
157 rose->state = ROSE_STATE_4;
158 rose_start_t2timer(sk);
159 rose_stop_idletimer(sk);
160 break;
161 }
162 rose_frames_acked(sk, nr);
163 if (ns == rose->vr) {
164 rose_start_idletimer(sk);
165 if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
166 __sock_queue_rcv_skb(sk, skb) == 0) {
167 rose->vr = (rose->vr + 1) % ROSE_MODULUS;
168 queued = 1;
169 } else {
170 /* Should never happen ! */
171 rose_write_internal(sk, ROSE_RESET_REQUEST);
172 rose->condition = 0x00;
173 rose->vs = 0;
174 rose->vr = 0;
175 rose->va = 0;
176 rose->vl = 0;
177 rose->state = ROSE_STATE_4;
178 rose_start_t2timer(sk);
179 rose_stop_idletimer(sk);
180 break;
181 }
182 if (atomic_read(&sk->sk_rmem_alloc) >
183 (sk->sk_rcvbuf >> 1))
184 rose->condition |= ROSE_COND_OWN_RX_BUSY;
185 }
186 /*
187 * If the window is full, ack the frame, else start the
188 * acknowledge hold back timer.
189 */
190 if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
191 rose->condition &= ~ROSE_COND_ACK_PENDING;
192 rose_stop_timer(sk);
193 rose_enquiry_response(sk);
194 } else {
195 rose->condition |= ROSE_COND_ACK_PENDING;
196 rose_start_hbtimer(sk);
197 }
198 break;
199
200 default:
201 printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
202 break;
203 }
204
205 return queued;
206}
207
208/*
209 * State machine for state 4, Awaiting Reset Confirmation State.
210 * The handling of the timer(s) is in file rose_timer.c
211 * Handling of state 0 and connection release is in af_rose.c.
212 */
213static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
214{
215 struct rose_sock *rose = rose_sk(sk);
216
217 switch (frametype) {
218 case ROSE_RESET_REQUEST:
219 rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
220 fallthrough;
221 case ROSE_RESET_CONFIRMATION:
222 rose_stop_timer(sk);
223 rose_start_idletimer(sk);
224 rose->condition = 0x00;
225 rose->va = 0;
226 rose->vr = 0;
227 rose->vs = 0;
228 rose->vl = 0;
229 rose->state = ROSE_STATE_3;
230 rose_requeue_frames(sk);
231 break;
232
233 case ROSE_CLEAR_REQUEST:
234 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
235 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
236 rose->neighbour->use--;
237 break;
238
239 default:
240 break;
241 }
242
243 return 0;
244}
245
246/*
247 * State machine for state 5, Awaiting Call Acceptance State.
248 * The handling of the timer(s) is in file rose_timer.c
249 * Handling of state 0 and connection release is in af_rose.c.
250 */
251static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
252{
253 if (frametype == ROSE_CLEAR_REQUEST) {
254 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
255 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
256 rose_sk(sk)->neighbour->use--;
257 }
258
259 return 0;
260}
261
262/* Higher level upcall for a LAPB frame */
263int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
264{
265 struct rose_sock *rose = rose_sk(sk);
266 int queued = 0, frametype, ns, nr, q, d, m;
267
268 if (rose->state == ROSE_STATE_0)
269 return 0;
270
271 frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
272
273 switch (rose->state) {
274 case ROSE_STATE_1:
275 queued = rose_state1_machine(sk, skb, frametype);
276 break;
277 case ROSE_STATE_2:
278 queued = rose_state2_machine(sk, skb, frametype);
279 break;
280 case ROSE_STATE_3:
281 queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
282 break;
283 case ROSE_STATE_4:
284 queued = rose_state4_machine(sk, skb, frametype);
285 break;
286 case ROSE_STATE_5:
287 queued = rose_state5_machine(sk, skb, frametype);
288 break;
289 }
290
291 rose_kick(sk);
292
293 return queued;
294}