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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * X.25 Packet Layer release 002
3 *
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +09004 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/kernel.h>
21#include <linux/netdevice.h>
22#include <linux/skbuff.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090023#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <net/sock.h>
25#include <linux/if_arp.h>
26#include <net/x25.h>
Andrew Hendry5ebfbc02010-04-22 16:12:36 -070027#include <net/x25device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
30{
31 struct sock *sk;
32 unsigned short frametype;
33 unsigned int lci;
34
Matthew Daleycb101ed2011-10-14 18:45:04 +000035 if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
36 return 0;
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 frametype = skb->data[2];
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +090039 lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41 /*
42 * LCI of zero is always for us, and its always a link control
43 * frame.
44 */
45 if (lci == 0) {
46 x25_link_control(skb, nb, frametype);
47 return 0;
48 }
49
50 /*
51 * Find an existing socket.
52 */
53 if ((sk = x25_find_socket(lci, nb)) != NULL) {
54 int queued = 1;
55
Arnaldo Carvalho de Melobadff6d2007-03-13 13:06:52 -030056 skb_reset_transport_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 bh_lock_sock(sk);
58 if (!sock_owned_by_user(sk)) {
59 queued = x25_process_rx_frame(sk, skb);
60 } else {
Zhu Yia3a858f2010-03-04 18:01:47 +000061 queued = !sk_add_backlog(sk, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 }
63 bh_unlock_sock(sk);
Andrew Hendry9d0f7d22007-01-15 19:29:31 -080064 sock_put(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 return queued;
66 }
67
68 /*
69 * Is is a Call Request ? if so process it.
70 */
71 if (frametype == X25_CALL_REQUEST)
72 return x25_rx_call_request(skb, nb, lci);
73
74 /*
Andrew Hendry95a9dc42007-02-08 13:34:02 -080075 * Its not a Call Request, nor is it a control frame.
76 * Can we forward it?
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 */
Andrew Hendry95a9dc42007-02-08 13:34:02 -080078
79 if (x25_forward_data(lci, nb, skb)) {
80 if (frametype == X25_CLEAR_CONFIRMATION) {
81 x25_clear_forward_by_lci(lci);
82 }
83 kfree_skb(skb);
84 return 1;
85 }
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087/*
88 x25_transmit_clear_request(nb, lci, 0x0D);
89*/
90
91 if (frametype != X25_CLEAR_CONFIRMATION)
92 printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
93
94 return 0;
95}
96
97int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
David S. Millerf2ccd8f2005-08-09 19:34:12 -070098 struct packet_type *ptype, struct net_device *orig_dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
100 struct sk_buff *nskb;
101 struct x25_neigh *nb;
102
YOSHIFUJI Hideaki721499e2008-07-19 22:34:43 -0700103 if (!net_eq(dev_net(dev), &init_net))
Eric W. Biedermane730c152007-09-17 11:53:39 -0700104 goto drop;
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 nskb = skb_copy(skb, GFP_ATOMIC);
107 if (!nskb)
108 goto drop;
109 kfree_skb(skb);
110 skb = nskb;
111
112 /*
113 * Packet received from unrecognised device, throw it away.
114 */
115 nb = x25_get_neigh(dev);
116 if (!nb) {
117 printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
118 goto drop;
119 }
120
Matthew Daleycb101ed2011-10-14 18:45:04 +0000121 if (!pskb_may_pull(skb, 1))
122 return 0;
123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 switch (skb->data[0]) {
Andrew Hendry5ebfbc02010-04-22 16:12:36 -0700125
126 case X25_IFACE_DATA:
127 skb_pull(skb, 1);
128 if (x25_receive_data(skb, nb)) {
129 x25_neigh_put(nb);
130 goto out;
131 }
132 break;
133
134 case X25_IFACE_CONNECT:
135 x25_link_established(nb);
136 break;
137
138 case X25_IFACE_DISCONNECT:
139 x25_link_terminated(nb);
140 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 }
142 x25_neigh_put(nb);
143drop:
144 kfree_skb(skb);
145out:
146 return 0;
147}
148
149void x25_establish_link(struct x25_neigh *nb)
150{
151 struct sk_buff *skb;
152 unsigned char *ptr;
153
154 switch (nb->dev->type) {
Joe Perchesfddc5f32011-07-01 09:43:13 +0000155 case ARPHRD_X25:
156 if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
157 printk(KERN_ERR "x25_dev: out of memory\n");
158 return;
159 }
160 ptr = skb_put(skb, 1);
161 *ptr = X25_IFACE_CONNECT;
162 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
Igor Maravić29c36262011-12-12 02:58:23 +0000164#if IS_ENABLED(CONFIG_LLC)
Joe Perchesfddc5f32011-07-01 09:43:13 +0000165 case ARPHRD_ETHER:
166 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167#endif
Joe Perchesfddc5f32011-07-01 09:43:13 +0000168 default:
169 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 }
171
172 skb->protocol = htons(ETH_P_X25);
173 skb->dev = nb->dev;
174
175 dev_queue_xmit(skb);
176}
177
178void x25_terminate_link(struct x25_neigh *nb)
179{
180 struct sk_buff *skb;
181 unsigned char *ptr;
182
Igor Maravić29c36262011-12-12 02:58:23 +0000183#if IS_ENABLED(CONFIG_LLC)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 if (nb->dev->type == ARPHRD_ETHER)
185 return;
186#endif
187 if (nb->dev->type != ARPHRD_X25)
188 return;
189
190 skb = alloc_skb(1, GFP_ATOMIC);
191 if (!skb) {
192 printk(KERN_ERR "x25_dev: out of memory\n");
193 return;
194 }
195
196 ptr = skb_put(skb, 1);
Andrew Hendry5ebfbc02010-04-22 16:12:36 -0700197 *ptr = X25_IFACE_DISCONNECT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
199 skb->protocol = htons(ETH_P_X25);
200 skb->dev = nb->dev;
201 dev_queue_xmit(skb);
202}
203
204void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
205{
206 unsigned char *dptr;
207
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -0700208 skb_reset_network_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210 switch (nb->dev->type) {
Joe Perchesfddc5f32011-07-01 09:43:13 +0000211 case ARPHRD_X25:
212 dptr = skb_push(skb, 1);
213 *dptr = X25_IFACE_DATA;
214 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Igor Maravić29c36262011-12-12 02:58:23 +0000216#if IS_ENABLED(CONFIG_LLC)
Joe Perchesfddc5f32011-07-01 09:43:13 +0000217 case ARPHRD_ETHER:
218 kfree_skb(skb);
219 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220#endif
Joe Perchesfddc5f32011-07-01 09:43:13 +0000221 default:
222 kfree_skb(skb);
223 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 }
225
226 skb->protocol = htons(ETH_P_X25);
227 skb->dev = nb->dev;
228
229 dev_queue_xmit(skb);
230}