1 /*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine, randomly fail to work with new
5 * releases, misbehave and/or generally screw up. It might even work.
6 *
7 * This code REQUIRES 2.1.15 or higher
8 *
9 * This module:
10 * This module is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 *
15 * History
16 * X.25 001 Jonathan Naylor Started coding.
17 * 2000-09-04 Henner Eisen Prevent freeing a dangling skb.
18 */
19
20 #include <linux/config.h>
21 #include <linux/errno.h>
22 #include <linux/types.h>
23 #include <linux/socket.h>
24 #include <linux/in.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/timer.h>
28 #include <linux/string.h>
29 #include <linux/sockios.h>
30 #include <linux/net.h>
31 #include <linux/stat.h>
32 #include <linux/inet.h>
33 #include <linux/netdevice.h>
34 #include <linux/skbuff.h>
35 #include <net/sock.h>
36 #include <asm/segment.h>
37 #include <asm/system.h>
38 #include <asm/uaccess.h>
39 #include <linux/fcntl.h>
40 #include <linux/termios.h> /* For TIOCINQ/OUTQ */
41 #include <linux/mm.h>
42 #include <linux/interrupt.h>
43 #include <linux/notifier.h>
44 #include <linux/proc_fs.h>
45 #include <linux/if_arp.h>
46 #include <net/x25.h>
47
x25_receive_data(struct sk_buff * skb,struct x25_neigh * neigh)48 static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *neigh)
49 {
50 struct sock *sk;
51 unsigned short frametype;
52 unsigned int lci;
53
54 frametype = skb->data[2];
55 lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
56
57 /*
58 * LCI of zero is always for us, and its always a link control
59 * frame.
60 */
61 if (lci == 0) {
62 x25_link_control(skb, neigh, frametype);
63 return 0;
64 }
65
66 /*
67 * Find an existing socket.
68 */
69 if ((sk = x25_find_socket(lci, neigh)) != NULL) {
70 int queued = 1;
71
72 skb->h.raw = skb->data;
73 bh_lock_sock(sk);
74 if (!sk->lock.users) {
75 queued = x25_process_rx_frame(sk, skb);
76 } else {
77 sk_add_backlog(sk, skb);
78 }
79 bh_unlock_sock(sk);
80 return queued;
81 }
82
83 /*
84 * Is is a Call Request ? if so process it.
85 */
86 if (frametype == X25_CALL_REQUEST)
87 return x25_rx_call_request(skb, neigh, lci);
88
89 /*
90 * Its not a Call Request, nor is it a control frame.
91 * Let caller throw it away.
92 */
93 /*
94 x25_transmit_clear_request(neigh, lci, 0x0D);
95 */
96 printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
97
98 return 0;
99 }
100
x25_lapb_receive_frame(struct sk_buff * skb,struct net_device * dev,struct packet_type * ptype)101 int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
102 {
103 struct x25_neigh *neigh;
104 int queued;
105
106 skb->sk = NULL;
107
108 /*
109 * Packet received from unrecognised device, throw it away.
110 */
111 if ((neigh = x25_get_neigh(dev)) == NULL) {
112 printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
113 kfree_skb(skb);
114 return 0;
115 }
116
117 switch (skb->data[0]) {
118 case 0x00:
119 skb_pull(skb, 1);
120 queued = x25_receive_data(skb, neigh);
121 if( ! queued )
122 /* We need to free the skb ourselves because
123 * net_bh() won't care about our return code.
124 */
125 kfree_skb(skb);
126 return 0;
127
128 case 0x01:
129 x25_link_established(neigh);
130 kfree_skb(skb);
131 return 0;
132
133 case 0x02:
134 x25_link_terminated(neigh);
135 kfree_skb(skb);
136 return 0;
137
138 case 0x03:
139 kfree_skb(skb);
140 return 0;
141
142 default:
143 kfree_skb(skb);
144 return 0;
145 }
146 }
147
x25_llc_receive_frame(struct sk_buff * skb,struct net_device * dev,struct packet_type * ptype)148 int x25_llc_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
149 {
150 struct x25_neigh *neigh;
151
152 skb->sk = NULL;
153
154 /*
155 * Packet received from unrecognised device, throw it away.
156 */
157 if ((neigh = x25_get_neigh(dev)) == NULL) {
158 printk(KERN_DEBUG "X.25: unknown_neighbour - %s\n", dev->name);
159 kfree_skb(skb);
160 return 0;
161 }
162
163 return x25_receive_data(skb, neigh);
164 }
165
x25_establish_link(struct x25_neigh * neigh)166 void x25_establish_link(struct x25_neigh *neigh)
167 {
168 struct sk_buff *skb;
169 unsigned char *ptr;
170
171 switch (neigh->dev->type) {
172 case ARPHRD_X25:
173 if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
174 printk(KERN_ERR "x25_dev: out of memory\n");
175 return;
176 }
177 ptr = skb_put(skb, 1);
178 *ptr = 0x01;
179 break;
180
181 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
182 case ARPHRD_ETHER:
183 return;
184 #endif
185 default:
186 return;
187 }
188
189 skb->protocol = htons(ETH_P_X25);
190 skb->dev = neigh->dev;
191
192 dev_queue_xmit(skb);
193 }
194
x25_terminate_link(struct x25_neigh * neigh)195 void x25_terminate_link(struct x25_neigh *neigh)
196 {
197 struct sk_buff *skb;
198 unsigned char *ptr;
199
200 switch (neigh->dev->type) {
201 case ARPHRD_X25:
202 if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
203 printk(KERN_ERR "x25_dev: out of memory\n");
204 return;
205 }
206 ptr = skb_put(skb, 1);
207 *ptr = 0x02;
208 break;
209
210 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
211 case ARPHRD_ETHER:
212 return;
213 #endif
214 default:
215 return;
216 }
217
218 skb->protocol = htons(ETH_P_X25);
219 skb->dev = neigh->dev;
220
221 dev_queue_xmit(skb);
222 }
223
x25_send_frame(struct sk_buff * skb,struct x25_neigh * neigh)224 void x25_send_frame(struct sk_buff *skb, struct x25_neigh *neigh)
225 {
226 unsigned char *dptr;
227
228 skb->nh.raw = skb->data;
229
230 switch (neigh->dev->type) {
231 case ARPHRD_X25:
232 dptr = skb_push(skb, 1);
233 *dptr = 0x00;
234 break;
235
236 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
237 case ARPHRD_ETHER:
238 kfree_skb(skb);
239 return;
240 #endif
241 default:
242 kfree_skb(skb);
243 return;
244 }
245
246 skb->protocol = htons(ETH_P_X25);
247 skb->dev = neigh->dev;
248
249 dev_queue_xmit(skb);
250 }
251