Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
nr_in.c
Go to the documentation of this file.
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 ([email protected])
8  * Copyright Darryl Miles G7LED ([email protected])
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/timer.h>
16 #include <linux/string.h>
17 #include <linux/sockios.h>
18 #include <linux/net.h>
19 #include <linux/slab.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 <linux/fcntl.h>
28 #include <linux/mm.h>
29 #include <linux/interrupt.h>
30 #include <net/netrom.h>
31 
32 static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
33 {
34  struct sk_buff *skbo, *skbn = skb;
35  struct nr_sock *nr = nr_sk(sk);
36 
37  skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
38 
39  nr_start_idletimer(sk);
40 
41  if (more) {
42  nr->fraglen += skb->len;
43  skb_queue_tail(&nr->frag_queue, skb);
44  return 0;
45  }
46 
47  if (!more && nr->fraglen > 0) { /* End of fragment */
48  nr->fraglen += skb->len;
49  skb_queue_tail(&nr->frag_queue, skb);
50 
51  if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
52  return 1;
53 
54  skb_reset_transport_header(skbn);
55 
56  while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
57  skb_copy_from_linear_data(skbo,
58  skb_put(skbn, skbo->len),
59  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  case NR_RESET:
103  if (sysctl_netrom_reset_circuit)
104  nr_disconnect(sk, ECONNRESET);
105  break;
106 
107  default:
108  break;
109  }
110  return 0;
111 }
112 
113 /*
114  * State machine for state 2, Awaiting Release State.
115  * The handling of the timer(s) is in file nr_timer.c
116  * Handling of state 0 and connection release is in netrom.c.
117  */
118 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
119  int frametype)
120 {
121  switch (frametype) {
122  case NR_CONNACK | NR_CHOKE_FLAG:
123  nr_disconnect(sk, ECONNRESET);
124  break;
125 
126  case NR_DISCREQ:
127  nr_write_internal(sk, NR_DISCACK);
128 
129  case NR_DISCACK:
130  nr_disconnect(sk, 0);
131  break;
132 
133  case NR_RESET:
134  if (sysctl_netrom_reset_circuit)
135  nr_disconnect(sk, ECONNRESET);
136  break;
137 
138  default:
139  break;
140  }
141  return 0;
142 }
143 
144 /*
145  * State machine for state 3, Connected State.
146  * The handling of the timer(s) is in file nr_timer.c
147  * Handling of state 0 and connection release is in netrom.c.
148  */
149 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
150 {
151  struct nr_sock *nrom = nr_sk(sk);
152  struct sk_buff_head temp_queue;
153  struct sk_buff *skbn;
154  unsigned short save_vr;
155  unsigned short nr, ns;
156  int queued = 0;
157 
158  nr = skb->data[18];
159  ns = skb->data[17];
160 
161  switch (frametype) {
162  case NR_CONNREQ:
163  nr_write_internal(sk, NR_CONNACK);
164  break;
165 
166  case NR_DISCREQ:
167  nr_write_internal(sk, NR_DISCACK);
168  nr_disconnect(sk, 0);
169  break;
170 
171  case NR_CONNACK | NR_CHOKE_FLAG:
172  case NR_DISCACK:
173  nr_disconnect(sk, ECONNRESET);
174  break;
175 
176  case NR_INFOACK:
177  case NR_INFOACK | NR_CHOKE_FLAG:
178  case NR_INFOACK | NR_NAK_FLAG:
179  case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
180  if (frametype & NR_CHOKE_FLAG) {
181  nrom->condition |= NR_COND_PEER_RX_BUSY;
182  nr_start_t4timer(sk);
183  } else {
184  nrom->condition &= ~NR_COND_PEER_RX_BUSY;
185  nr_stop_t4timer(sk);
186  }
187  if (!nr_validate_nr(sk, nr)) {
188  break;
189  }
190  if (frametype & NR_NAK_FLAG) {
191  nr_frames_acked(sk, nr);
192  nr_send_nak_frame(sk);
193  } else {
194  if (nrom->condition & NR_COND_PEER_RX_BUSY) {
195  nr_frames_acked(sk, nr);
196  } else {
197  nr_check_iframes_acked(sk, nr);
198  }
199  }
200  break;
201 
202  case NR_INFO:
203  case NR_INFO | NR_NAK_FLAG:
204  case NR_INFO | NR_CHOKE_FLAG:
205  case NR_INFO | NR_MORE_FLAG:
206  case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
207  case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
208  case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
209  case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
210  if (frametype & NR_CHOKE_FLAG) {
211  nrom->condition |= NR_COND_PEER_RX_BUSY;
212  nr_start_t4timer(sk);
213  } else {
214  nrom->condition &= ~NR_COND_PEER_RX_BUSY;
215  nr_stop_t4timer(sk);
216  }
217  if (nr_validate_nr(sk, nr)) {
218  if (frametype & NR_NAK_FLAG) {
219  nr_frames_acked(sk, nr);
220  nr_send_nak_frame(sk);
221  } else {
222  if (nrom->condition & NR_COND_PEER_RX_BUSY) {
223  nr_frames_acked(sk, nr);
224  } else {
225  nr_check_iframes_acked(sk, nr);
226  }
227  }
228  }
229  queued = 1;
230  skb_queue_head(&nrom->reseq_queue, skb);
231  if (nrom->condition & NR_COND_OWN_RX_BUSY)
232  break;
233  skb_queue_head_init(&temp_queue);
234  do {
235  save_vr = nrom->vr;
236  while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
237  ns = skbn->data[17];
238  if (ns == nrom->vr) {
239  if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
240  nrom->vr = (nrom->vr + 1) % NR_MODULUS;
241  } else {
242  nrom->condition |= NR_COND_OWN_RX_BUSY;
243  skb_queue_tail(&temp_queue, skbn);
244  }
245  } else if (nr_in_rx_window(sk, ns)) {
246  skb_queue_tail(&temp_queue, skbn);
247  } else {
248  kfree_skb(skbn);
249  }
250  }
251  while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
252  skb_queue_tail(&nrom->reseq_queue, skbn);
253  }
254  } while (save_vr != nrom->vr);
255  /*
256  * Window is full, ack it immediately.
257  */
258  if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
259  nr_enquiry_response(sk);
260  } else {
261  if (!(nrom->condition & NR_COND_ACK_PENDING)) {
262  nrom->condition |= NR_COND_ACK_PENDING;
263  nr_start_t2timer(sk);
264  }
265  }
266  break;
267 
268  case NR_RESET:
269  if (sysctl_netrom_reset_circuit)
270  nr_disconnect(sk, ECONNRESET);
271  break;
272 
273  default:
274  break;
275  }
276  return queued;
277 }
278 
279 /* Higher level upcall for a LAPB frame - called with sk locked */
280 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
281 {
282  struct nr_sock *nr = nr_sk(sk);
283  int queued = 0, frametype;
284 
285  if (nr->state == NR_STATE_0)
286  return 0;
287 
288  frametype = skb->data[19];
289 
290  switch (nr->state) {
291  case NR_STATE_1:
292  queued = nr_state1_machine(sk, skb, frametype);
293  break;
294  case NR_STATE_2:
295  queued = nr_state2_machine(sk, skb, frametype);
296  break;
297  case NR_STATE_3:
298  queued = nr_state3_machine(sk, skb, frametype);
299  break;
300  }
301 
302  nr_kick(sk);
303 
304  return queued;
305 }
Generated on Thu Jan 10 2013 15:01:09 for Linux Kernel by   doxygen 1.8.2