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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * |
4 | * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) | |
5 | * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) | |
6 | */ | |
7 | #include <linux/errno.h> | |
8 | #include <linux/types.h> | |
9 | #include <linux/socket.h> | |
10 | #include <linux/in.h> | |
11 | #include <linux/kernel.h> | |
1da177e4 LT |
12 | #include <linux/timer.h> |
13 | #include <linux/string.h> | |
14 | #include <linux/sockios.h> | |
15 | #include <linux/net.h> | |
16 | #include <net/ax25.h> | |
17 | #include <linux/inet.h> | |
18 | #include <linux/netdevice.h> | |
19 | #include <linux/skbuff.h> | |
20 | #include <net/sock.h> | |
c752f073 | 21 | #include <net/tcp_states.h> |
7c0f6ba6 | 22 | #include <linux/uaccess.h> |
1da177e4 LT |
23 | #include <linux/fcntl.h> |
24 | #include <linux/mm.h> | |
25 | #include <linux/interrupt.h> | |
26 | ||
27 | /* | |
28 | * State machine for state 1, Awaiting Connection State. | |
29 | * The handling of the timer(s) is in file ax25_ds_timer.c. | |
30 | * Handling of state 0 and connection release is in ax25.c. | |
31 | */ | |
32 | static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type) | |
33 | { | |
34 | switch (frametype) { | |
35 | case AX25_SABM: | |
36 | ax25->modulus = AX25_MODULUS; | |
37 | ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; | |
38 | ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); | |
39 | break; | |
40 | ||
41 | case AX25_SABME: | |
42 | ax25->modulus = AX25_EMODULUS; | |
43 | ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW]; | |
44 | ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); | |
45 | break; | |
46 | ||
47 | case AX25_DISC: | |
48 | ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE); | |
49 | break; | |
50 | ||
51 | case AX25_UA: | |
52 | ax25_calculate_rtt(ax25); | |
53 | ax25_stop_t1timer(ax25); | |
54 | ax25_start_t3timer(ax25); | |
55 | ax25_start_idletimer(ax25); | |
56 | ax25->vs = 0; | |
57 | ax25->va = 0; | |
58 | ax25->vr = 0; | |
59 | ax25->state = AX25_STATE_3; | |
60 | ax25->n2count = 0; | |
61 | if (ax25->sk != NULL) { | |
62 | bh_lock_sock(ax25->sk); | |
63 | ax25->sk->sk_state = TCP_ESTABLISHED; | |
64 | /* | |
65 | * For WAIT_SABM connections we will produce an accept | |
66 | * ready socket here | |
67 | */ | |
68 | if (!sock_flag(ax25->sk, SOCK_DEAD)) | |
69 | ax25->sk->sk_state_change(ax25->sk); | |
70 | bh_unlock_sock(ax25->sk); | |
71 | } | |
72 | ax25_dama_on(ax25); | |
73 | ||
96de0e25 | 74 | /* according to DK4EG's spec we are required to |
1da177e4 LT |
75 | * send a RR RESPONSE FINAL NR=0. |
76 | */ | |
77 | ||
78 | ax25_std_enquiry_response(ax25); | |
79 | break; | |
80 | ||
81 | case AX25_DM: | |
82 | if (pf) | |
83 | ax25_disconnect(ax25, ECONNREFUSED); | |
84 | break; | |
85 | ||
86 | default: | |
87 | if (pf) | |
88 | ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); | |
89 | break; | |
90 | } | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | /* | |
96 | * State machine for state 2, Awaiting Release State. | |
97 | * The handling of the timer(s) is in file ax25_ds_timer.c | |
98 | * Handling of state 0 and connection release is in ax25.c. | |
99 | */ | |
100 | static int ax25_ds_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type) | |
101 | { | |
102 | switch (frametype) { | |
103 | case AX25_SABM: | |
104 | case AX25_SABME: | |
105 | ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); | |
106 | ax25_dama_off(ax25); | |
107 | break; | |
108 | ||
109 | case AX25_DISC: | |
110 | ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); | |
111 | ax25_dama_off(ax25); | |
112 | ax25_disconnect(ax25, 0); | |
113 | break; | |
114 | ||
115 | case AX25_DM: | |
116 | case AX25_UA: | |
117 | if (pf) { | |
118 | ax25_dama_off(ax25); | |
119 | ax25_disconnect(ax25, 0); | |
120 | } | |
121 | break; | |
122 | ||
123 | case AX25_I: | |
124 | case AX25_REJ: | |
125 | case AX25_RNR: | |
126 | case AX25_RR: | |
127 | if (pf) { | |
128 | ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); | |
129 | ax25_dama_off(ax25); | |
130 | } | |
131 | break; | |
132 | ||
133 | default: | |
134 | break; | |
135 | } | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | /* | |
141 | * State machine for state 3, Connected State. | |
142 | * The handling of the timer(s) is in file ax25_timer.c | |
143 | * Handling of state 0 and connection release is in ax25.c. | |
144 | */ | |
145 | static int ax25_ds_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type) | |
146 | { | |
147 | int queued = 0; | |
148 | ||
149 | switch (frametype) { | |
150 | case AX25_SABM: | |
151 | case AX25_SABME: | |
152 | if (frametype == AX25_SABM) { | |
153 | ax25->modulus = AX25_MODULUS; | |
154 | ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; | |
155 | } else { | |
156 | ax25->modulus = AX25_EMODULUS; | |
157 | ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW]; | |
158 | } | |
159 | ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); | |
160 | ax25_stop_t1timer(ax25); | |
161 | ax25_start_t3timer(ax25); | |
162 | ax25_start_idletimer(ax25); | |
163 | ax25->condition = 0x00; | |
164 | ax25->vs = 0; | |
165 | ax25->va = 0; | |
166 | ax25->vr = 0; | |
167 | ax25_requeue_frames(ax25); | |
168 | ax25_dama_on(ax25); | |
169 | break; | |
170 | ||
171 | case AX25_DISC: | |
172 | ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); | |
173 | ax25_dama_off(ax25); | |
174 | ax25_disconnect(ax25, 0); | |
175 | break; | |
176 | ||
177 | case AX25_DM: | |
178 | ax25_dama_off(ax25); | |
179 | ax25_disconnect(ax25, ECONNRESET); | |
180 | break; | |
181 | ||
182 | case AX25_RR: | |
183 | case AX25_RNR: | |
184 | if (frametype == AX25_RR) | |
185 | ax25->condition &= ~AX25_COND_PEER_RX_BUSY; | |
186 | else | |
187 | ax25->condition |= AX25_COND_PEER_RX_BUSY; | |
188 | ||
189 | if (ax25_validate_nr(ax25, nr)) { | |
190 | if (ax25_check_iframes_acked(ax25, nr)) | |
191 | ax25->n2count=0; | |
192 | if (type == AX25_COMMAND && pf) | |
193 | ax25_ds_enquiry_response(ax25); | |
194 | } else { | |
195 | ax25_ds_nr_error_recovery(ax25); | |
196 | ax25->state = AX25_STATE_1; | |
197 | } | |
198 | break; | |
199 | ||
200 | case AX25_REJ: | |
201 | ax25->condition &= ~AX25_COND_PEER_RX_BUSY; | |
202 | ||
203 | if (ax25_validate_nr(ax25, nr)) { | |
204 | if (ax25->va != nr) | |
205 | ax25->n2count=0; | |
206 | ||
207 | ax25_frames_acked(ax25, nr); | |
208 | ax25_calculate_rtt(ax25); | |
209 | ax25_stop_t1timer(ax25); | |
210 | ax25_start_t3timer(ax25); | |
211 | ax25_requeue_frames(ax25); | |
212 | ||
213 | if (type == AX25_COMMAND && pf) | |
214 | ax25_ds_enquiry_response(ax25); | |
215 | } else { | |
216 | ax25_ds_nr_error_recovery(ax25); | |
217 | ax25->state = AX25_STATE_1; | |
218 | } | |
219 | break; | |
220 | ||
221 | case AX25_I: | |
222 | if (!ax25_validate_nr(ax25, nr)) { | |
223 | ax25_ds_nr_error_recovery(ax25); | |
224 | ax25->state = AX25_STATE_1; | |
225 | break; | |
226 | } | |
227 | if (ax25->condition & AX25_COND_PEER_RX_BUSY) { | |
228 | ax25_frames_acked(ax25, nr); | |
229 | ax25->n2count = 0; | |
230 | } else { | |
231 | if (ax25_check_iframes_acked(ax25, nr)) | |
232 | ax25->n2count = 0; | |
233 | } | |
234 | if (ax25->condition & AX25_COND_OWN_RX_BUSY) { | |
235 | if (pf) ax25_ds_enquiry_response(ax25); | |
236 | break; | |
237 | } | |
238 | if (ns == ax25->vr) { | |
239 | ax25->vr = (ax25->vr + 1) % ax25->modulus; | |
240 | queued = ax25_rx_iframe(ax25, skb); | |
241 | if (ax25->condition & AX25_COND_OWN_RX_BUSY) | |
242 | ax25->vr = ns; /* ax25->vr - 1 */ | |
243 | ax25->condition &= ~AX25_COND_REJECT; | |
244 | if (pf) { | |
245 | ax25_ds_enquiry_response(ax25); | |
246 | } else { | |
247 | if (!(ax25->condition & AX25_COND_ACK_PENDING)) { | |
248 | ax25->condition |= AX25_COND_ACK_PENDING; | |
249 | ax25_start_t2timer(ax25); | |
250 | } | |
251 | } | |
252 | } else { | |
253 | if (ax25->condition & AX25_COND_REJECT) { | |
254 | if (pf) ax25_ds_enquiry_response(ax25); | |
255 | } else { | |
256 | ax25->condition |= AX25_COND_REJECT; | |
257 | ax25_ds_enquiry_response(ax25); | |
258 | ax25->condition &= ~AX25_COND_ACK_PENDING; | |
259 | } | |
260 | } | |
261 | break; | |
262 | ||
263 | case AX25_FRMR: | |
264 | case AX25_ILLEGAL: | |
265 | ax25_ds_establish_data_link(ax25); | |
266 | ax25->state = AX25_STATE_1; | |
267 | break; | |
268 | ||
269 | default: | |
270 | break; | |
271 | } | |
272 | ||
273 | return queued; | |
274 | } | |
275 | ||
276 | /* | |
277 | * Higher level upcall for a LAPB frame | |
278 | */ | |
279 | int ax25_ds_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type) | |
280 | { | |
281 | int queued = 0, frametype, ns, nr, pf; | |
282 | ||
283 | frametype = ax25_decode(ax25, skb, &ns, &nr, &pf); | |
284 | ||
285 | switch (ax25->state) { | |
286 | case AX25_STATE_1: | |
287 | queued = ax25_ds_state1_machine(ax25, skb, frametype, pf, type); | |
288 | break; | |
289 | case AX25_STATE_2: | |
290 | queued = ax25_ds_state2_machine(ax25, skb, frametype, pf, type); | |
291 | break; | |
292 | case AX25_STATE_3: | |
293 | queued = ax25_ds_state3_machine(ax25, skb, frametype, ns, nr, pf, type); | |
294 | break; | |
295 | } | |
296 | ||
297 | return queued; | |
298 | } |