[PATCH] sysfs: (driver/block) if show/store is missing return -EIO
[linux-2.6.git] / net / netrom / nr_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 Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8  * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
9  */
10 #include <linux/errno.h>
11 #include <linux/types.h>
12 #include <linux/socket.h>
13 #include <linux/in.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
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>
25 #include <net/tcp.h>
26 #include <net/ip.h>                     /* For ip_rcv */
27 #include <asm/uaccess.h>
28 #include <asm/system.h>
29 #include <linux/fcntl.h>
30 #include <linux/mm.h>
31 #include <linux/interrupt.h>
32 #include <net/netrom.h>
33
34 static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
35 {
36         struct sk_buff *skbo, *skbn = skb;
37         struct nr_sock *nr = nr_sk(sk);
38
39         skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
40
41         nr_start_idletimer(sk);
42
43         if (more) {
44                 nr->fraglen += skb->len;
45                 skb_queue_tail(&nr->frag_queue, skb);
46                 return 0;
47         }
48
49         if (!more && nr->fraglen > 0) { /* End of fragment */
50                 nr->fraglen += skb->len;
51                 skb_queue_tail(&nr->frag_queue, skb);
52
53                 if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
54                         return 1;
55
56                 skbn->h.raw = skbn->data;
57
58                 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
59                         memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
60                         kfree_skb(skbo);
61                 }
62
63                 nr->fraglen = 0;
64         }
65
66         return sock_queue_rcv_skb(sk, skbn);
67 }
68
69 /*
70  * State machine for state 1, Awaiting Connection State.
71  * The handling of the timer(s) is in file nr_timer.c.
72  * Handling of state 0 and connection release is in netrom.c.
73  */
74 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
75         int frametype)
76 {
77         switch (frametype) {
78         case NR_CONNACK: {
79                 struct nr_sock *nr = nr_sk(sk);
80
81                 nr_stop_t1timer(sk);
82                 nr_start_idletimer(sk);
83                 nr->your_index = skb->data[17];
84                 nr->your_id    = skb->data[18];
85                 nr->vs         = 0;
86                 nr->va         = 0;
87                 nr->vr         = 0;
88                 nr->vl         = 0;
89                 nr->state      = NR_STATE_3;
90                 nr->n2count    = 0;
91                 nr->window     = skb->data[20];
92                 sk->sk_state   = TCP_ESTABLISHED;
93                 if (!sock_flag(sk, SOCK_DEAD))
94                         sk->sk_state_change(sk);
95                 break;
96         }
97
98         case NR_CONNACK | NR_CHOKE_FLAG:
99                 nr_disconnect(sk, ECONNREFUSED);
100                 break;
101
102         default:
103                 break;
104         }
105         return 0;
106 }
107
108 /*
109  * State machine for state 2, Awaiting Release State.
110  * The handling of the timer(s) is in file nr_timer.c
111  * Handling of state 0 and connection release is in netrom.c.
112  */
113 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
114         int frametype)
115 {
116         switch (frametype) {
117         case NR_CONNACK | NR_CHOKE_FLAG:
118                 nr_disconnect(sk, ECONNRESET);
119                 break;
120
121         case NR_DISCREQ:
122                 nr_write_internal(sk, NR_DISCACK);
123
124         case NR_DISCACK:
125                 nr_disconnect(sk, 0);
126                 break;
127
128         default:
129                 break;
130         }
131         return 0;
132 }
133
134 /*
135  * State machine for state 3, Connected State.
136  * The handling of the timer(s) is in file nr_timer.c
137  * Handling of state 0 and connection release is in netrom.c.
138  */
139 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
140 {
141         struct nr_sock *nrom = nr_sk(sk);
142         struct sk_buff_head temp_queue;
143         struct sk_buff *skbn;
144         unsigned short save_vr;
145         unsigned short nr, ns;
146         int queued = 0;
147
148         nr = skb->data[18];
149         ns = skb->data[17];
150
151         switch (frametype) {
152         case NR_CONNREQ:
153                 nr_write_internal(sk, NR_CONNACK);
154                 break;
155
156         case NR_DISCREQ:
157                 nr_write_internal(sk, NR_DISCACK);
158                 nr_disconnect(sk, 0);
159                 break;
160
161         case NR_CONNACK | NR_CHOKE_FLAG:
162         case NR_DISCACK:
163                 nr_disconnect(sk, ECONNRESET);
164                 break;
165
166         case NR_INFOACK:
167         case NR_INFOACK | NR_CHOKE_FLAG:
168         case NR_INFOACK | NR_NAK_FLAG:
169         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
170                 if (frametype & NR_CHOKE_FLAG) {
171                         nrom->condition |= NR_COND_PEER_RX_BUSY;
172                         nr_start_t4timer(sk);
173                 } else {
174                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
175                         nr_stop_t4timer(sk);
176                 }
177                 if (!nr_validate_nr(sk, nr)) {
178                         break;
179                 }
180                 if (frametype & NR_NAK_FLAG) {
181                         nr_frames_acked(sk, nr);
182                         nr_send_nak_frame(sk);
183                 } else {
184                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
185                                 nr_frames_acked(sk, nr);
186                         } else {
187                                 nr_check_iframes_acked(sk, nr);
188                         }
189                 }
190                 break;
191
192         case NR_INFO:
193         case NR_INFO | NR_NAK_FLAG:
194         case NR_INFO | NR_CHOKE_FLAG:
195         case NR_INFO | NR_MORE_FLAG:
196         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
197         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
198         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
199         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
200                 if (frametype & NR_CHOKE_FLAG) {
201                         nrom->condition |= NR_COND_PEER_RX_BUSY;
202                         nr_start_t4timer(sk);
203                 } else {
204                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
205                         nr_stop_t4timer(sk);
206                 }
207                 if (nr_validate_nr(sk, nr)) {
208                         if (frametype & NR_NAK_FLAG) {
209                                 nr_frames_acked(sk, nr);
210                                 nr_send_nak_frame(sk);
211                         } else {
212                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
213                                         nr_frames_acked(sk, nr);
214                                 } else {
215                                         nr_check_iframes_acked(sk, nr);
216                                 }
217                         }
218                 }
219                 queued = 1;
220                 skb_queue_head(&nrom->reseq_queue, skb);
221                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
222                         break;
223                 skb_queue_head_init(&temp_queue);
224                 do {
225                         save_vr = nrom->vr;
226                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
227                                 ns = skbn->data[17];
228                                 if (ns == nrom->vr) {
229                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
230                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
231                                         } else {
232                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
233                                                 skb_queue_tail(&temp_queue, skbn);
234                                         }
235                                 } else if (nr_in_rx_window(sk, ns)) {
236                                         skb_queue_tail(&temp_queue, skbn);
237                                 } else {
238                                         kfree_skb(skbn);
239                                 }
240                         }
241                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
242                                 skb_queue_tail(&nrom->reseq_queue, skbn);
243                         }
244                 } while (save_vr != nrom->vr);
245                 /*
246                  * Window is full, ack it immediately.
247                  */
248                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
249                         nr_enquiry_response(sk);
250                 } else {
251                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
252                                 nrom->condition |= NR_COND_ACK_PENDING;
253                                 nr_start_t2timer(sk);
254                         }
255                 }
256                 break;
257
258         default:
259                 break;
260         }
261         return queued;
262 }
263
264 /* Higher level upcall for a LAPB frame - called with sk locked */
265 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
266 {
267         struct nr_sock *nr = nr_sk(sk);
268         int queued = 0, frametype;
269
270         if (nr->state == NR_STATE_0)
271                 return 0;
272
273         frametype = skb->data[19];
274
275         switch (nr->state) {
276         case NR_STATE_1:
277                 queued = nr_state1_machine(sk, skb, frametype);
278                 break;
279         case NR_STATE_2:
280                 queued = nr_state2_machine(sk, skb, frametype);
281                 break;
282         case NR_STATE_3:
283                 queued = nr_state3_machine(sk, skb, frametype);
284                 break;
285         }
286
287         nr_kick(sk);
288
289         return queued;
290 }