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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 | * | |
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/types.h> | |
13 | #include <linux/socket.h> | |
14 | #include <linux/in.h> | |
15 | #include <linux/kernel.h> | |
1da177e4 LT |
16 | #include <linux/timer.h> |
17 | #include <linux/string.h> | |
18 | #include <linux/sockios.h> | |
19 | #include <linux/net.h> | |
20 | #include <net/ax25.h> | |
21 | #include <linux/inet.h> | |
22 | #include <linux/netdevice.h> | |
23 | #include <linux/skbuff.h> | |
24 | #include <net/sock.h> | |
c752f073 | 25 | #include <net/tcp_states.h> |
1da177e4 LT |
26 | #include <linux/fcntl.h> |
27 | #include <linux/mm.h> | |
28 | #include <linux/interrupt.h> | |
29 | #include <net/rose.h> | |
30 | ||
31 | /* | |
32 | * State machine for state 1, Awaiting Call Accepted State. | |
33 | * The handling of the timer(s) is in file rose_timer.c. | |
34 | * Handling of state 0 and connection release is in af_rose.c. | |
35 | */ | |
36 | static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
37 | { | |
38 | struct rose_sock *rose = rose_sk(sk); | |
39 | ||
40 | switch (frametype) { | |
41 | case ROSE_CALL_ACCEPTED: | |
42 | rose_stop_timer(sk); | |
43 | rose_start_idletimer(sk); | |
44 | rose->condition = 0x00; | |
45 | rose->vs = 0; | |
46 | rose->va = 0; | |
47 | rose->vr = 0; | |
48 | rose->vl = 0; | |
49 | rose->state = ROSE_STATE_3; | |
50 | sk->sk_state = TCP_ESTABLISHED; | |
51 | if (!sock_flag(sk, SOCK_DEAD)) | |
52 | sk->sk_state_change(sk); | |
53 | break; | |
54 | ||
55 | case ROSE_CLEAR_REQUEST: | |
56 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
57 | rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); | |
58 | rose->neighbour->use--; | |
59 | break; | |
60 | ||
61 | default: | |
62 | break; | |
63 | } | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
68 | /* | |
69 | * State machine for state 2, Awaiting Clear Confirmation State. | |
70 | * The handling of the timer(s) is in file rose_timer.c | |
71 | * Handling of state 0 and connection release is in af_rose.c. | |
72 | */ | |
73 | static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
74 | { | |
75 | struct rose_sock *rose = rose_sk(sk); | |
76 | ||
77 | switch (frametype) { | |
78 | case ROSE_CLEAR_REQUEST: | |
79 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
80 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
81 | rose->neighbour->use--; | |
82 | break; | |
83 | ||
84 | case ROSE_CLEAR_CONFIRMATION: | |
85 | rose_disconnect(sk, 0, -1, -1); | |
86 | rose->neighbour->use--; | |
87 | break; | |
88 | ||
89 | default: | |
90 | break; | |
91 | } | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | /* | |
97 | * State machine for state 3, Connected State. | |
98 | * The handling of the timer(s) is in file rose_timer.c | |
99 | * Handling of state 0 and connection release is in af_rose.c. | |
100 | */ | |
101 | static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) | |
102 | { | |
103 | struct rose_sock *rose = rose_sk(sk); | |
104 | int queued = 0; | |
105 | ||
106 | switch (frametype) { | |
107 | case ROSE_RESET_REQUEST: | |
108 | rose_stop_timer(sk); | |
109 | rose_start_idletimer(sk); | |
110 | rose_write_internal(sk, ROSE_RESET_CONFIRMATION); | |
111 | rose->condition = 0x00; | |
112 | rose->vs = 0; | |
113 | rose->vr = 0; | |
114 | rose->va = 0; | |
115 | rose->vl = 0; | |
116 | rose_requeue_frames(sk); | |
117 | break; | |
118 | ||
119 | case ROSE_CLEAR_REQUEST: | |
120 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
121 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
122 | rose->neighbour->use--; | |
123 | break; | |
124 | ||
125 | case ROSE_RR: | |
126 | case ROSE_RNR: | |
127 | if (!rose_validate_nr(sk, nr)) { | |
128 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
129 | rose->condition = 0x00; | |
130 | rose->vs = 0; | |
131 | rose->vr = 0; | |
132 | rose->va = 0; | |
133 | rose->vl = 0; | |
134 | rose->state = ROSE_STATE_4; | |
135 | rose_start_t2timer(sk); | |
136 | rose_stop_idletimer(sk); | |
137 | } else { | |
138 | rose_frames_acked(sk, nr); | |
139 | if (frametype == ROSE_RNR) { | |
140 | rose->condition |= ROSE_COND_PEER_RX_BUSY; | |
141 | } else { | |
142 | rose->condition &= ~ROSE_COND_PEER_RX_BUSY; | |
143 | } | |
144 | } | |
145 | break; | |
146 | ||
147 | case ROSE_DATA: /* XXX */ | |
148 | rose->condition &= ~ROSE_COND_PEER_RX_BUSY; | |
149 | if (!rose_validate_nr(sk, nr)) { | |
150 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
151 | rose->condition = 0x00; | |
152 | rose->vs = 0; | |
153 | rose->vr = 0; | |
154 | rose->va = 0; | |
155 | rose->vl = 0; | |
156 | rose->state = ROSE_STATE_4; | |
157 | rose_start_t2timer(sk); | |
158 | rose_stop_idletimer(sk); | |
159 | break; | |
160 | } | |
161 | rose_frames_acked(sk, nr); | |
162 | if (ns == rose->vr) { | |
163 | rose_start_idletimer(sk); | |
f4979fce WB |
164 | if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 && |
165 | __sock_queue_rcv_skb(sk, skb) == 0) { | |
1da177e4 LT |
166 | rose->vr = (rose->vr + 1) % ROSE_MODULUS; |
167 | queued = 1; | |
168 | } else { | |
169 | /* Should never happen ! */ | |
170 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
171 | rose->condition = 0x00; | |
172 | rose->vs = 0; | |
173 | rose->vr = 0; | |
174 | rose->va = 0; | |
175 | rose->vl = 0; | |
176 | rose->state = ROSE_STATE_4; | |
177 | rose_start_t2timer(sk); | |
178 | rose_stop_idletimer(sk); | |
179 | break; | |
180 | } | |
181 | if (atomic_read(&sk->sk_rmem_alloc) > | |
95b7d924 | 182 | (sk->sk_rcvbuf >> 1)) |
1da177e4 LT |
183 | rose->condition |= ROSE_COND_OWN_RX_BUSY; |
184 | } | |
185 | /* | |
186 | * If the window is full, ack the frame, else start the | |
187 | * acknowledge hold back timer. | |
188 | */ | |
189 | if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) { | |
190 | rose->condition &= ~ROSE_COND_ACK_PENDING; | |
191 | rose_stop_timer(sk); | |
192 | rose_enquiry_response(sk); | |
193 | } else { | |
194 | rose->condition |= ROSE_COND_ACK_PENDING; | |
195 | rose_start_hbtimer(sk); | |
196 | } | |
197 | break; | |
198 | ||
199 | default: | |
200 | printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype); | |
201 | break; | |
202 | } | |
203 | ||
204 | return queued; | |
205 | } | |
206 | ||
207 | /* | |
208 | * State machine for state 4, Awaiting Reset Confirmation State. | |
209 | * The handling of the timer(s) is in file rose_timer.c | |
210 | * Handling of state 0 and connection release is in af_rose.c. | |
211 | */ | |
212 | static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
213 | { | |
214 | struct rose_sock *rose = rose_sk(sk); | |
215 | ||
216 | switch (frametype) { | |
217 | case ROSE_RESET_REQUEST: | |
218 | rose_write_internal(sk, ROSE_RESET_CONFIRMATION); | |
df561f66 | 219 | fallthrough; |
1da177e4 LT |
220 | case ROSE_RESET_CONFIRMATION: |
221 | rose_stop_timer(sk); | |
222 | rose_start_idletimer(sk); | |
223 | rose->condition = 0x00; | |
224 | rose->va = 0; | |
225 | rose->vr = 0; | |
226 | rose->vs = 0; | |
227 | rose->vl = 0; | |
228 | rose->state = ROSE_STATE_3; | |
229 | rose_requeue_frames(sk); | |
230 | break; | |
231 | ||
232 | case ROSE_CLEAR_REQUEST: | |
233 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
234 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
235 | rose->neighbour->use--; | |
236 | break; | |
237 | ||
238 | default: | |
239 | break; | |
240 | } | |
241 | ||
242 | return 0; | |
243 | } | |
244 | ||
245 | /* | |
246 | * State machine for state 5, Awaiting Call Acceptance State. | |
247 | * The handling of the timer(s) is in file rose_timer.c | |
248 | * Handling of state 0 and connection release is in af_rose.c. | |
249 | */ | |
250 | static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
251 | { | |
252 | if (frametype == ROSE_CLEAR_REQUEST) { | |
253 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
254 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
255 | rose_sk(sk)->neighbour->use--; | |
256 | } | |
257 | ||
258 | return 0; | |
259 | } | |
260 | ||
261 | /* Higher level upcall for a LAPB frame */ | |
262 | int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb) | |
263 | { | |
264 | struct rose_sock *rose = rose_sk(sk); | |
265 | int queued = 0, frametype, ns, nr, q, d, m; | |
266 | ||
267 | if (rose->state == ROSE_STATE_0) | |
268 | return 0; | |
269 | ||
270 | frametype = rose_decode(skb, &ns, &nr, &q, &d, &m); | |
271 | ||
272 | switch (rose->state) { | |
273 | case ROSE_STATE_1: | |
274 | queued = rose_state1_machine(sk, skb, frametype); | |
275 | break; | |
276 | case ROSE_STATE_2: | |
277 | queued = rose_state2_machine(sk, skb, frametype); | |
278 | break; | |
279 | case ROSE_STATE_3: | |
280 | queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m); | |
281 | break; | |
282 | case ROSE_STATE_4: | |
283 | queued = rose_state4_machine(sk, skb, frametype); | |
284 | break; | |
285 | case ROSE_STATE_5: | |
286 | queued = rose_state5_machine(sk, skb, frametype); | |
287 | break; | |
288 | } | |
289 | ||
290 | rose_kick(sk); | |
291 | ||
292 | return queued; | |
293 | } |