netfilter: nf_conntrack: fix rt6i_gateway checks for H.323 helper
[linux-3.10.git] / net / rose / rose_in.c
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>
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>
28 #include <net/tcp_states.h>
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) >
184                             (sk->sk_rcvbuf >> 1))
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 }