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