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 */
9 #include <linux/errno.h>
10 #include <linux/types.h>
11 #include <linux/socket.h>
12 #include <linux/in.h>
13 #include <linux/kernel.h>
14 #include <linux/timer.h>
15 #include <linux/string.h>
16 #include <linux/sockios.h>
17 #include <linux/net.h>
18 #include <net/ax25.h>
19 #include <linux/inet.h>
20 #include <linux/netdevice.h>
21 #include <linux/skbuff.h>
22 #include <net/sock.h>
23 #include <net/tcp_states.h>
24 #include <asm/uaccess.h>
25 #include <asm/system.h>
26 #include <linux/fcntl.h>
27 #include <linux/mm.h>
28 #include <linux/interrupt.h>
29 #include <net/netrom.h>
30
31 /*
32 * This routine purges all of the queues of frames.
33 */
34 void nr_clear_queues(struct sock *sk)
35 {
36 struct nr_sock *nr = nr_sk(sk);
37
38 skb_queue_purge(&sk->sk_write_queue);
39 skb_queue_purge(&nr->ack_queue);
40 skb_queue_purge(&nr->reseq_queue);
41 skb_queue_purge(&nr->frag_queue);
42 }
43
44 /*
45 * This routine purges the input queue of those frames that have been
46 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
47 * SDL diagram.
48 */
49 void nr_frames_acked(struct sock *sk, unsigned short nr)
50 {
51 struct nr_sock *nrom = nr_sk(sk);
52 struct sk_buff *skb;
53
54 /*
55 * Remove all the ack-ed frames from the ack queue.
56 */
57 if (nrom->va != nr) {
58 while (skb_peek(&nrom->ack_queue) != NULL && nrom->va != nr) {
59 skb = skb_dequeue(&nrom->ack_queue);
60 kfree_skb(skb);
61 nrom->va = (nrom->va + 1) % NR_MODULUS;
62 }
63 }
64 }
65
66 /*
67 * Requeue all the un-ack-ed frames on the output queue to be picked
68 * up by nr_kick called from the timer. This arrangement handles the
69 * possibility of an empty output queue.
70 */
71 void nr_requeue_frames(struct sock *sk)
72 {
73 struct sk_buff *skb, *skb_prev = NULL;
74
75 while ((skb = skb_dequeue(&nr_sk(sk)->ack_queue)) != NULL) {
76 if (skb_prev == NULL)
77 skb_queue_head(&sk->sk_write_queue, skb);
78 else
79 skb_append(skb_prev, skb, &sk->sk_write_queue);
80 skb_prev = skb;
81 }
82 }
83
84 /*
85 * Validate that the value of nr is between va and vs. Return true or
86 * false for testing.
87 */
88 int nr_validate_nr(struct sock *sk, unsigned short nr)
89 {
90 struct nr_sock *nrom = nr_sk(sk);
91 unsigned short vc = nrom->va;
92
93 while (vc != nrom->vs) {
94 if (nr == vc) return 1;
95 vc = (vc + 1) % NR_MODULUS;
96 }
97
98 return nr == nrom->vs;
99 }
100
101 /*
102 * Check that ns is within the receive window.
103 */
104 int nr_in_rx_window(struct sock *sk, unsigned short ns)
105 {
106 struct nr_sock *nr = nr_sk(sk);
107 unsigned short vc = nr->vr;
108 unsigned short vt = (nr->vl + nr->window) % NR_MODULUS;
109
110 while (vc != vt) {
111 if (ns == vc) return 1;
112 vc = (vc + 1) % NR_MODULUS;
113 }
114
115 return 0;
116 }
117
118 /*
119 * This routine is called when the HDLC layer internally generates a
120 * control frame.
121 */
122 void nr_write_internal(struct sock *sk, int frametype)
123 {
124 struct nr_sock *nr = nr_sk(sk);
125 struct sk_buff *skb;
126 unsigned char *dptr;
127 int len, timeout;
128
129 len = NR_NETWORK_LEN + NR_TRANSPORT_LEN;
130
131 switch (frametype & 0x0F) {
132 case NR_CONNREQ:
133 len += 17;
134 break;
135 case NR_CONNACK:
136 len += (nr->bpqext) ? 2 : 1;
137 break;
138 case NR_DISCREQ:
139 case NR_DISCACK:
140 case NR_INFOACK:
141 break;
142 default:
143 printk(KERN_ERR "NET/ROM: nr_write_internal - invalid frame type %d\n", frametype);
144 return;
145 }
146
147 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
148 return;
149
150 /*
151 * Space for AX.25 and NET/ROM network header
152 */
153 skb_reserve(skb, NR_NETWORK_LEN);
154
155 dptr = skb_put(skb, skb_tailroom(skb));
156
157 switch (frametype & 0x0F) {
158 case NR_CONNREQ:
159 timeout = nr->t1 / HZ;
160 *dptr++ = nr->my_index;
161 *dptr++ = nr->my_id;
162 *dptr++ = 0;
163 *dptr++ = 0;
164 *dptr++ = frametype;
165 *dptr++ = nr->window;
166 memcpy(dptr, &nr->user_addr, AX25_ADDR_LEN);
167 dptr[6] &= ~AX25_CBIT;
168 dptr[6] &= ~AX25_EBIT;
169 dptr[6] |= AX25_SSSID_SPARE;
170 dptr += AX25_ADDR_LEN;
171 memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN);
172 dptr[6] &= ~AX25_CBIT;
173 dptr[6] &= ~AX25_EBIT;
174 dptr[6] |= AX25_SSSID_SPARE;
175 dptr += AX25_ADDR_LEN;
176 *dptr++ = timeout % 256;
177 *dptr++ = timeout / 256;
178 break;
179
180 case NR_CONNACK:
181 *dptr++ = nr->your_index;
182 *dptr++ = nr->your_id;
183 *dptr++ = nr->my_index;
184 *dptr++ = nr->my_id;
185 *dptr++ = frametype;
186 *dptr++ = nr->window;
187 if (nr->bpqext) *dptr++ = sysctl_netrom_network_ttl_initialiser;
188 break;
189
190 case NR_DISCREQ:
191 case NR_DISCACK:
192 *dptr++ = nr->your_index;
193 *dptr++ = nr->your_id;
194 *dptr++ = 0;
195 *dptr++ = 0;
196 *dptr++ = frametype;
197 break;
198
199 case NR_INFOACK:
200 *dptr++ = nr->your_index;
201 *dptr++ = nr->your_id;
202 *dptr++ = 0;
203 *dptr++ = nr->vr;
204 *dptr++ = frametype;
205 break;
206 }
207
208 nr_transmit_buffer(sk, skb);
209 }
210
211 /*
212 * This routine is called to send an error reply.
213 */
214 void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags)
215 {
216 struct sk_buff *skbn;
217 unsigned char *dptr;
218 int len;
219
220 len = NR_NETWORK_LEN + NR_TRANSPORT_LEN + 1;
221
222 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL)
223 return;
224
225 skb_reserve(skbn, 0);
226
227 dptr = skb_put(skbn, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
228
229 skb_copy_from_linear_data_offset(skb, 7, dptr, AX25_ADDR_LEN);
230 dptr[6] &= ~AX25_CBIT;
231 dptr[6] &= ~AX25_EBIT;
232 dptr[6] |= AX25_SSSID_SPARE;
233 dptr += AX25_ADDR_LEN;
234
235 skb_copy_from_linear_data(skb, dptr, AX25_ADDR_LEN);
236 dptr[6] &= ~AX25_CBIT;
237 dptr[6] |= AX25_EBIT;
238 dptr[6] |= AX25_SSSID_SPARE;
239 dptr += AX25_ADDR_LEN;
240
241 *dptr++ = sysctl_netrom_network_ttl_initialiser;
242
243 if (mine) {
244 *dptr++ = 0;
245 *dptr++ = 0;
246 *dptr++ = skb->data[15];
247 *dptr++ = skb->data[16];
248 } else {
249 *dptr++ = skb->data[15];
250 *dptr++ = skb->data[16];
251 *dptr++ = 0;
252 *dptr++ = 0;
253 }
254
255 *dptr++ = cmdflags;
256 *dptr++ = 0;
257
258 if (!nr_route_frame(skbn, NULL))
259 kfree_skb(skbn);
260 }
261
262 void nr_disconnect(struct sock *sk, int reason)
263 {
264 nr_stop_t1timer(sk);
265 nr_stop_t2timer(sk);
266 nr_stop_t4timer(sk);
267 nr_stop_idletimer(sk);
268
269 nr_clear_queues(sk);
270
271 nr_sk(sk)->state = NR_STATE_0;
272
273 sk->sk_state = TCP_CLOSE;
274 sk->sk_err = reason;
275 sk->sk_shutdown |= SEND_SHUTDOWN;
276
277 if (!sock_flag(sk, SOCK_DEAD)) {
278 sk->sk_state_change(sk);
279 sock_set_flag(sk, SOCK_DEAD);
280 }
281 }
282
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