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1da177e4 LT |
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) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) | |
8 | * | |
9 | * Most of this code is based on the SDL diagrams published in the 7th ARRL | |
10 | * Computer Networking Conference papers. The diagrams have mistakes in them, | |
11 | * but are mostly correct. Before you modify the code could you read the SDL | |
12 | * diagrams as the code is not obvious and probably very easy to break. | |
13 | */ | |
14 | #include <linux/errno.h> | |
15 | #include <linux/types.h> | |
16 | #include <linux/socket.h> | |
17 | #include <linux/in.h> | |
18 | #include <linux/kernel.h> | |
1da177e4 LT |
19 | #include <linux/timer.h> |
20 | #include <linux/string.h> | |
21 | #include <linux/sockios.h> | |
22 | #include <linux/net.h> | |
23 | #include <net/ax25.h> | |
24 | #include <linux/inet.h> | |
25 | #include <linux/netdevice.h> | |
26 | #include <linux/skbuff.h> | |
27 | #include <net/sock.h> | |
c752f073 | 28 | #include <net/tcp_states.h> |
1da177e4 LT |
29 | #include <linux/fcntl.h> |
30 | #include <linux/mm.h> | |
31 | #include <linux/interrupt.h> | |
32 | #include <net/rose.h> | |
33 | ||
34 | /* | |
35 | * State machine for state 1, Awaiting Call Accepted State. | |
36 | * The handling of the timer(s) is in file rose_timer.c. | |
37 | * Handling of state 0 and connection release is in af_rose.c. | |
38 | */ | |
39 | static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
40 | { | |
41 | struct rose_sock *rose = rose_sk(sk); | |
42 | ||
43 | switch (frametype) { | |
44 | case ROSE_CALL_ACCEPTED: | |
45 | rose_stop_timer(sk); | |
46 | rose_start_idletimer(sk); | |
47 | rose->condition = 0x00; | |
48 | rose->vs = 0; | |
49 | rose->va = 0; | |
50 | rose->vr = 0; | |
51 | rose->vl = 0; | |
52 | rose->state = ROSE_STATE_3; | |
53 | sk->sk_state = TCP_ESTABLISHED; | |
54 | if (!sock_flag(sk, SOCK_DEAD)) | |
55 | sk->sk_state_change(sk); | |
56 | break; | |
57 | ||
58 | case ROSE_CLEAR_REQUEST: | |
59 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
60 | rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); | |
61 | rose->neighbour->use--; | |
62 | break; | |
63 | ||
64 | default: | |
65 | break; | |
66 | } | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | /* | |
72 | * State machine for state 2, Awaiting Clear Confirmation State. | |
73 | * The handling of the timer(s) is in file rose_timer.c | |
74 | * Handling of state 0 and connection release is in af_rose.c. | |
75 | */ | |
76 | static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
77 | { | |
78 | struct rose_sock *rose = rose_sk(sk); | |
79 | ||
80 | switch (frametype) { | |
81 | case ROSE_CLEAR_REQUEST: | |
82 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
83 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
84 | rose->neighbour->use--; | |
85 | break; | |
86 | ||
87 | case ROSE_CLEAR_CONFIRMATION: | |
88 | rose_disconnect(sk, 0, -1, -1); | |
89 | rose->neighbour->use--; | |
90 | break; | |
91 | ||
92 | default: | |
93 | break; | |
94 | } | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | /* | |
100 | * State machine for state 3, Connected State. | |
101 | * The handling of the timer(s) is in file rose_timer.c | |
102 | * Handling of state 0 and connection release is in af_rose.c. | |
103 | */ | |
104 | static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) | |
105 | { | |
106 | struct rose_sock *rose = rose_sk(sk); | |
107 | int queued = 0; | |
108 | ||
109 | switch (frametype) { | |
110 | case ROSE_RESET_REQUEST: | |
111 | rose_stop_timer(sk); | |
112 | rose_start_idletimer(sk); | |
113 | rose_write_internal(sk, ROSE_RESET_CONFIRMATION); | |
114 | rose->condition = 0x00; | |
115 | rose->vs = 0; | |
116 | rose->vr = 0; | |
117 | rose->va = 0; | |
118 | rose->vl = 0; | |
119 | rose_requeue_frames(sk); | |
120 | break; | |
121 | ||
122 | case ROSE_CLEAR_REQUEST: | |
123 | rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); | |
124 | rose_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
125 | rose->neighbour->use--; | |
126 | break; | |
127 | ||
128 | case ROSE_RR: | |
129 | case ROSE_RNR: | |
130 | if (!rose_validate_nr(sk, nr)) { | |
131 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
132 | rose->condition = 0x00; | |
133 | rose->vs = 0; | |
134 | rose->vr = 0; | |
135 | rose->va = 0; | |
136 | rose->vl = 0; | |
137 | rose->state = ROSE_STATE_4; | |
138 | rose_start_t2timer(sk); | |
139 | rose_stop_idletimer(sk); | |
140 | } else { | |
141 | rose_frames_acked(sk, nr); | |
142 | if (frametype == ROSE_RNR) { | |
143 | rose->condition |= ROSE_COND_PEER_RX_BUSY; | |
144 | } else { | |
145 | rose->condition &= ~ROSE_COND_PEER_RX_BUSY; | |
146 | } | |
147 | } | |
148 | break; | |
149 | ||
150 | case ROSE_DATA: /* XXX */ | |
151 | rose->condition &= ~ROSE_COND_PEER_RX_BUSY; | |
152 | if (!rose_validate_nr(sk, nr)) { | |
153 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
154 | rose->condition = 0x00; | |
155 | rose->vs = 0; | |
156 | rose->vr = 0; | |
157 | rose->va = 0; | |
158 | rose->vl = 0; | |
159 | rose->state = ROSE_STATE_4; | |
160 | rose_start_t2timer(sk); | |
161 | rose_stop_idletimer(sk); | |
162 | break; | |
163 | } | |
164 | rose_frames_acked(sk, nr); | |
165 | if (ns == rose->vr) { | |
166 | rose_start_idletimer(sk); | |
167 | if (sock_queue_rcv_skb(sk, skb) == 0) { | |
168 | rose->vr = (rose->vr + 1) % ROSE_MODULUS; | |
169 | queued = 1; | |
170 | } else { | |
171 | /* Should never happen ! */ | |
172 | rose_write_internal(sk, ROSE_RESET_REQUEST); | |
173 | rose->condition = 0x00; | |
174 | rose->vs = 0; | |
175 | rose->vr = 0; | |
176 | rose->va = 0; | |
177 | rose->vl = 0; | |
178 | rose->state = ROSE_STATE_4; | |
179 | rose_start_t2timer(sk); | |
180 | rose_stop_idletimer(sk); | |
181 | break; | |
182 | } | |
183 | if (atomic_read(&sk->sk_rmem_alloc) > | |
95b7d924 | 184 | (sk->sk_rcvbuf >> 1)) |
1da177e4 LT |
185 | rose->condition |= ROSE_COND_OWN_RX_BUSY; |
186 | } | |
187 | /* | |
188 | * If the window is full, ack the frame, else start the | |
189 | * acknowledge hold back timer. | |
190 | */ | |
191 | if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) { | |
192 | rose->condition &= ~ROSE_COND_ACK_PENDING; | |
193 | rose_stop_timer(sk); | |
194 | rose_enquiry_response(sk); | |
195 | } else { | |
196 | rose->condition |= ROSE_COND_ACK_PENDING; | |
197 | rose_start_hbtimer(sk); | |
198 | } | |
199 | break; | |
200 | ||
201 | default: | |
202 | printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype); | |
203 | break; | |
204 | } | |
205 | ||
206 | return queued; | |
207 | } | |
208 | ||
209 | /* | |
210 | * State machine for state 4, Awaiting Reset Confirmation State. | |
211 | * The handling of the timer(s) is in file rose_timer.c | |
212 | * Handling of state 0 and connection release is in af_rose.c. | |
213 | */ | |
214 | static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
215 | { | |
216 | struct rose_sock *rose = rose_sk(sk); | |
217 | ||
218 | switch (frametype) { | |
219 | case ROSE_RESET_REQUEST: | |
220 | rose_write_internal(sk, ROSE_RESET_CONFIRMATION); | |
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 | */ | |
251 | static 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 */ | |
263 | int 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 | } |