blob: 36fc3bf6d8827c4a47de80900ebee0a5ab54e7fa [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/kernel.h>
22#include <linux/netdevice.h>
23#include <linux/skbuff.h>
24#include <net/sock.h>
25#include <linux/if_arp.h>
26#include <net/x25.h>
27
28static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
29{
30 struct sock *sk;
31 unsigned short frametype;
32 unsigned int lci;
33
34 frametype = skb->data[2];
35 lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
36
37 /*
38 * LCI of zero is always for us, and its always a link control
39 * frame.
40 */
41 if (lci == 0) {
42 x25_link_control(skb, nb, frametype);
43 return 0;
44 }
45
46 /*
47 * Find an existing socket.
48 */
49 if ((sk = x25_find_socket(lci, nb)) != NULL) {
50 int queued = 1;
51
52 skb->h.raw = skb->data;
53 bh_lock_sock(sk);
54 if (!sock_owned_by_user(sk)) {
55 queued = x25_process_rx_frame(sk, skb);
56 } else {
57 sk_add_backlog(sk, skb);
58 }
59 bh_unlock_sock(sk);
60 return queued;
61 }
62
63 /*
64 * Is is a Call Request ? if so process it.
65 */
66 if (frametype == X25_CALL_REQUEST)
67 return x25_rx_call_request(skb, nb, lci);
68
69 /*
70 * Its not a Call Request, nor is it a control frame.
71 * Let caller throw it away.
72 */
73/*
74 x25_transmit_clear_request(nb, lci, 0x0D);
75*/
76
77 if (frametype != X25_CLEAR_CONFIRMATION)
78 printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
79
80 return 0;
81}
82
83int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
84 struct packet_type *ptype)
85{
86 struct sk_buff *nskb;
87 struct x25_neigh *nb;
88
89 nskb = skb_copy(skb, GFP_ATOMIC);
90 if (!nskb)
91 goto drop;
92 kfree_skb(skb);
93 skb = nskb;
94
95 /*
96 * Packet received from unrecognised device, throw it away.
97 */
98 nb = x25_get_neigh(dev);
99 if (!nb) {
100 printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
101 goto drop;
102 }
103
104 switch (skb->data[0]) {
105 case 0x00:
106 skb_pull(skb, 1);
107 if (x25_receive_data(skb, nb)) {
108 x25_neigh_put(nb);
109 goto out;
110 }
111 break;
112 case 0x01:
113 x25_link_established(nb);
114 break;
115 case 0x02:
116 x25_link_terminated(nb);
117 break;
118 }
119 x25_neigh_put(nb);
120drop:
121 kfree_skb(skb);
122out:
123 return 0;
124}
125
126void x25_establish_link(struct x25_neigh *nb)
127{
128 struct sk_buff *skb;
129 unsigned char *ptr;
130
131 switch (nb->dev->type) {
132 case ARPHRD_X25:
133 if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
134 printk(KERN_ERR "x25_dev: out of memory\n");
135 return;
136 }
137 ptr = skb_put(skb, 1);
138 *ptr = 0x01;
139 break;
140
141#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
142 case ARPHRD_ETHER:
143 return;
144#endif
145 default:
146 return;
147 }
148
149 skb->protocol = htons(ETH_P_X25);
150 skb->dev = nb->dev;
151
152 dev_queue_xmit(skb);
153}
154
155void x25_terminate_link(struct x25_neigh *nb)
156{
157 struct sk_buff *skb;
158 unsigned char *ptr;
159
160#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
161 if (nb->dev->type == ARPHRD_ETHER)
162 return;
163#endif
164 if (nb->dev->type != ARPHRD_X25)
165 return;
166
167 skb = alloc_skb(1, GFP_ATOMIC);
168 if (!skb) {
169 printk(KERN_ERR "x25_dev: out of memory\n");
170 return;
171 }
172
173 ptr = skb_put(skb, 1);
174 *ptr = 0x02;
175
176 skb->protocol = htons(ETH_P_X25);
177 skb->dev = nb->dev;
178 dev_queue_xmit(skb);
179}
180
181void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
182{
183 unsigned char *dptr;
184
185 skb->nh.raw = skb->data;
186
187 switch (nb->dev->type) {
188 case ARPHRD_X25:
189 dptr = skb_push(skb, 1);
190 *dptr = 0x00;
191 break;
192
193#if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
194 case ARPHRD_ETHER:
195 kfree_skb(skb);
196 return;
197#endif
198 default:
199 kfree_skb(skb);
200 return;
201 }
202
203 skb->protocol = htons(ETH_P_X25);
204 skb->dev = nb->dev;
205
206 dev_queue_xmit(skb);
207}