1 /*
2 * NET/ROM release 007
3 *
4 * This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Most of this code is based on the SDL diagrams published in the 7th
13 * ARRL Computer Networking Conference papers. The diagrams have mistakes
14 * in them, but are mostly correct. Before you modify the code could you
15 * read the SDL diagrams as the code is not obvious and probably very
16 * easy to break;
17 *
18 * History
19 * NET/ROM 001 Jonathan(G4KLX) Cloned from ax25_in.c
20 * NET/ROM 003 Jonathan(G4KLX) Added NET/ROM fragment reception.
21 * Darryl(G7LED) Added missing INFO with NAK case, optimized
22 * INFOACK handling, removed reconnect on error.
23 * NET/ROM 006 Jonathan(G4KLX) Hdrincl removal changes.
24 * NET/ROM 007 Jonathan(G4KLX) New timer architecture.
25 */
26
27 #include <linux/errno.h>
28 #include <linux/types.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/kernel.h>
32 #include <linux/sched.h>
33 #include <linux/timer.h>
34 #include <linux/string.h>
35 #include <linux/sockios.h>
36 #include <linux/net.h>
37 #include <net/ax25.h>
38 #include <linux/inet.h>
39 #include <linux/netdevice.h>
40 #include <linux/skbuff.h>
41 #include <net/sock.h>
42 #include <net/ip.h> /* For ip_rcv */
43 #include <asm/uaccess.h>
44 #include <asm/system.h>
45 #include <linux/fcntl.h>
46 #include <linux/mm.h>
47 #include <linux/interrupt.h>
48 #include <net/netrom.h>
49
50 static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
51 {
52 struct sk_buff *skbo, *skbn = skb;
53
54 skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
55
56 nr_start_idletimer(sk);
57
58 if (more) {
59 sk->protinfo.nr->fraglen += skb->len;
60 skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
61 return 0;
62 }
63
64 if (!more && sk->protinfo.nr->fraglen > 0) { /* End of fragment */
65 sk->protinfo.nr->fraglen += skb->len;
66 skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
67
68 if ((skbn = alloc_skb(sk->protinfo.nr->fraglen, GFP_ATOMIC)) == NULL)
69 return 1;
70
71 skbn->h.raw = skbn->data;
72
73 while ((skbo = skb_dequeue(&sk->protinfo.nr->frag_queue)) != NULL) {
74 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
75 kfree_skb(skbo);
76 }
77
78 sk->protinfo.nr->fraglen = 0;
79 }
80
81 return sock_queue_rcv_skb(sk, skbn);
82 }
83
84 /*
85 * State machine for state 1, Awaiting Connection State.
86 * The handling of the timer(s) is in file nr_timer.c.
87 * Handling of state 0 and connection release is in netrom.c.
88 */
89 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
90 {
91 switch (frametype) {
92
93 case NR_CONNACK:
94 nr_stop_t1timer(sk);
95 nr_start_idletimer(sk);
96 sk->protinfo.nr->your_index = skb->data[17];
97 sk->protinfo.nr->your_id = skb->data[18];
98 sk->protinfo.nr->vs = 0;
99 sk->protinfo.nr->va = 0;
100 sk->protinfo.nr->vr = 0;
101 sk->protinfo.nr->vl = 0;
102 sk->protinfo.nr->state = NR_STATE_3;
103 sk->protinfo.nr->n2count = 0;
104 sk->protinfo.nr->window = skb->data[20];
105 sk->state = TCP_ESTABLISHED;
106 if (!sk->dead)
107 sk->state_change(sk);
108 break;
109
110 case NR_CONNACK | NR_CHOKE_FLAG:
111 nr_disconnect(sk, ECONNREFUSED);
112 break;
113
114 default:
115 break;
116 }
117
118 return 0;
119 }
120
121 /*
122 * State machine for state 2, Awaiting Release State.
123 * The handling of the timer(s) is in file nr_timer.c
124 * Handling of state 0 and connection release is in netrom.c.
125 */
126 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
127 {
128 switch (frametype) {
129
130 case NR_CONNACK | NR_CHOKE_FLAG:
131 nr_disconnect(sk, ECONNRESET);
132 break;
133
134 case NR_DISCREQ:
135 nr_write_internal(sk, NR_DISCACK);
136
137 case NR_DISCACK:
138 nr_disconnect(sk, 0);
139 break;
140
141 default:
142 break;
143 }
144
145 return 0;
146 }
147
148 /*
149 * State machine for state 3, Connected State.
150 * The handling of the timer(s) is in file nr_timer.c
151 * Handling of state 0 and connection release is in netrom.c.
152 */
153 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
154 {
155 struct sk_buff_head temp_queue;
156 struct sk_buff *skbn;
157 unsigned short save_vr;
158 unsigned short nr, ns;
159 int queued = 0;
160
161 nr = skb->data[18];
162 ns = skb->data[17];
163
164 switch (frametype) {
165
166 case NR_CONNREQ:
167 nr_write_internal(sk, NR_CONNACK);
168 break;
169
170 case NR_DISCREQ:
171 nr_write_internal(sk, NR_DISCACK);
172 nr_disconnect(sk, 0);
173 break;
174
175 case NR_CONNACK | NR_CHOKE_FLAG:
176 case NR_DISCACK:
177 nr_disconnect(sk, ECONNRESET);
178 break;
179
180 case NR_INFOACK:
181 case NR_INFOACK | NR_CHOKE_FLAG:
182 case NR_INFOACK | NR_NAK_FLAG:
183 case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
184 if (frametype & NR_CHOKE_FLAG) {
185 sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
186 nr_start_t4timer(sk);
187 } else {
188 sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
189 nr_stop_t4timer(sk);
190 }
191 if (!nr_validate_nr(sk, nr)) {
192 break;
193 }
194 if (frametype & NR_NAK_FLAG) {
195 nr_frames_acked(sk, nr);
196 nr_send_nak_frame(sk);
197 } else {
198 if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
199 nr_frames_acked(sk, nr);
200 } else {
201 nr_check_iframes_acked(sk, nr);
202 }
203 }
204 break;
205
206 case NR_INFO:
207 case NR_INFO | NR_NAK_FLAG:
208 case NR_INFO | NR_CHOKE_FLAG:
209 case NR_INFO | NR_MORE_FLAG:
210 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
211 case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
212 case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
213 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
214 if (frametype & NR_CHOKE_FLAG) {
215 sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
216 nr_start_t4timer(sk);
217 } else {
218 sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
219 nr_stop_t4timer(sk);
220 }
221 if (nr_validate_nr(sk, nr)) {
222 if (frametype & NR_NAK_FLAG) {
223 nr_frames_acked(sk, nr);
224 nr_send_nak_frame(sk);
225 } else {
226 if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
227 nr_frames_acked(sk, nr);
228 } else {
229 nr_check_iframes_acked(sk, nr);
230 }
231 }
232 }
233 queued = 1;
234 skb_queue_head(&sk->protinfo.nr->reseq_queue, skb);
235 if (sk->protinfo.nr->condition & NR_COND_OWN_RX_BUSY)
236 break;
237 skb_queue_head_init(&temp_queue);
238 do {
239 save_vr = sk->protinfo.nr->vr;
240 while ((skbn = skb_dequeue(&sk->protinfo.nr->reseq_queue)) != NULL) {
241 ns = skbn->data[17];
242 if (ns == sk->protinfo.nr->vr) {
243 if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
244 sk->protinfo.nr->vr = (sk->protinfo.nr->vr + 1) % NR_MODULUS;
245 } else {
246 sk->protinfo.nr->condition |= NR_COND_OWN_RX_BUSY;
247 skb_queue_tail(&temp_queue, skbn);
248 }
249 } else if (nr_in_rx_window(sk, ns)) {
250 skb_queue_tail(&temp_queue, skbn);
251 } else {
252 kfree_skb(skbn);
253 }
254 }
255 while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
256 skb_queue_tail(&sk->protinfo.nr->reseq_queue, skbn);
257 }
258 } while (save_vr != sk->protinfo.nr->vr);
259 /*
260 * Window is full, ack it immediately.
261 */
262 if (((sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS) == sk->protinfo.nr->vr) {
263 nr_enquiry_response(sk);
264 } else {
265 if (!(sk->protinfo.nr->condition & NR_COND_ACK_PENDING)) {
266 sk->protinfo.nr->condition |= NR_COND_ACK_PENDING;
267 nr_start_t2timer(sk);
268 }
269 }
270 break;
271
272 default:
273 break;
274 }
275
276 return queued;
277 }
278
279 /* Higher level upcall for a LAPB frame */
280 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
281 {
282 int queued = 0, frametype;
283
284 if (sk->protinfo.nr->state == NR_STATE_0)
285 return 0;
286
287 frametype = skb->data[19];
288
289 switch (sk->protinfo.nr->state) {
290 case NR_STATE_1:
291 queued = nr_state1_machine(sk, skb, frametype);
292 break;
293 case NR_STATE_2:
294 queued = nr_state2_machine(sk, skb, frametype);
295 break;
296 case NR_STATE_3:
297 queued = nr_state3_machine(sk, skb, frametype);
298 break;
299 }
300
301 nr_kick(sk);
302
303 return queued;
304 }
305
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