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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/errno.h>
10#include <linux/types.h>
11#include <linux/socket.h>
12#include <linux/in.h>
13#include <linux/kernel.h>
Ralf Baechle70868ea2006-05-03 23:25:17 -070014#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/timer.h>
16#include <linux/string.h>
17#include <linux/sockios.h>
18#include <linux/net.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090019#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <net/ax25.h>
21#include <linux/inet.h>
22#include <linux/netdevice.h>
23#include <linux/if_arp.h>
24#include <linux/skbuff.h>
25#include <net/sock.h>
26#include <asm/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/fcntl.h>
28#include <linux/termios.h> /* For TIOCINQ/OUTQ */
29#include <linux/mm.h>
30#include <linux/interrupt.h>
31#include <linux/notifier.h>
32#include <linux/proc_fs.h>
33#include <linux/stat.h>
34#include <linux/netfilter.h>
35#include <linux/sysctl.h>
36#include <net/ip.h>
37#include <net/arp.h>
38
39/*
40 * IP over AX.25 encapsulation.
41 */
42
43/*
44 * Shove an AX.25 UI header on an IP packet and handle ARP
45 */
46
47#ifdef CONFIG_INET
48
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -070049int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
50 unsigned short type, const void *daddr,
Eric Dumazet95c96172012-04-15 05:58:06 +000051 const void *saddr, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
53 unsigned char *buff;
54
55 /* they sometimes come back to us... */
56 if (type == ETH_P_AX25)
57 return 0;
58
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090059 /* header is an AX.25 UI frame from us to them */
60 buff = skb_push(skb, AX25_HEADER_LEN);
61 *buff++ = 0x00; /* KISS DATA */
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 if (daddr != NULL)
64 memcpy(buff, daddr, dev->addr_len); /* Address specified */
65
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090066 buff[6] &= ~AX25_CBIT;
67 buff[6] &= ~AX25_EBIT;
68 buff[6] |= AX25_SSSID_SPARE;
69 buff += AX25_ADDR_LEN;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090071 if (saddr != NULL)
72 memcpy(buff, saddr, dev->addr_len);
73 else
74 memcpy(buff, dev->dev_addr, dev->addr_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090076 buff[6] &= ~AX25_CBIT;
77 buff[6] |= AX25_EBIT;
78 buff[6] |= AX25_SSSID_SPARE;
79 buff += AX25_ADDR_LEN;
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090081 *buff++ = AX25_UI; /* UI */
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090083 /* Append a suitable AX.25 PID */
84 switch (type) {
85 case ETH_P_IP:
86 *buff++ = AX25_P_IP;
87 break;
88 case ETH_P_ARP:
89 *buff++ = AX25_P_ARP;
90 break;
91 default:
92 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
93 *buff++ = 0;
94 break;
95 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 if (daddr != NULL)
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +090098 return AX25_HEADER_LEN;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
100 return -AX25_HEADER_LEN; /* Unfinished header */
101}
102
103int ax25_rebuild_header(struct sk_buff *skb)
104{
105 struct sk_buff *ourskb;
106 unsigned char *bp = skb->data;
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700107 ax25_route *route;
108 struct net_device *dev = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 ax25_address *src, *dst;
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700110 ax25_digi *digipeat = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 ax25_dev *ax25_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 ax25_cb *ax25;
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700113 char ip_mode = ' ';
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
115 dst = (ax25_address *)(bp + 1);
116 src = (ax25_address *)(bp + 8);
117
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900118 if (arp_find(bp + 1, skb))
119 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700121 route = ax25_get_route(dst, NULL);
122 if (route) {
123 digipeat = route->digipeat;
124 dev = route->dev;
125 ip_mode = route->ip_mode;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700126 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
128 if (dev == NULL)
129 dev = skb->dev;
130
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900131 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
132 goto put;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 }
134
135 if (bp[16] == AX25_P_IP) {
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700136 if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 /*
138 * We copy the buffer and release the original thereby
139 * keeping it straight
140 *
141 * Note: we report 1 back so the caller will
142 * not feed the frame direct to the physical device
143 * We don't want that to happen. (It won't be upset
144 * as we have pulled the frame from the queue by
145 * freeing it).
146 *
147 * NB: TCP modifies buffers that are still
148 * on a device queue, thus we use skb_copy()
149 * instead of using skb_clone() unless this
150 * gets fixed.
151 */
152
153 ax25_address src_c;
154 ax25_address dst_c;
155
156 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
157 kfree_skb(skb);
158 goto put;
159 }
160
161 if (skb->sk != NULL)
162 skb_set_owner_w(ourskb, skb->sk);
163
164 kfree_skb(skb);
165 /* dl9sau: bugfix
166 * after kfree_skb(), dst and src which were pointer
167 * to bp which is part of skb->data would not be valid
168 * anymore hope that after skb_pull(ourskb, ..) our
169 * dsc_c and src_c will not become invalid
170 */
171 bp = ourskb->data;
172 dst_c = *(ax25_address *)(bp + 1);
173 src_c = *(ax25_address *)(bp + 8);
174
175 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
Arnaldo Carvalho de Meloc1d2bbe2007-04-10 20:45:18 -0700176 skb_reset_network_header(ourskb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
178 ax25=ax25_send_frame(
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900179 ourskb,
180 ax25_dev->values[AX25_VALUES_PACLEN],
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 &src_c,
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700182 &dst_c, digipeat, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 if (ax25) {
184 ax25_cb_put(ax25);
185 }
186 goto put;
187 }
188 }
189
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900190 bp[7] &= ~AX25_CBIT;
191 bp[7] &= ~AX25_EBIT;
192 bp[7] |= AX25_SSSID_SPARE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900194 bp[14] &= ~AX25_CBIT;
195 bp[14] |= AX25_EBIT;
196 bp[14] |= AX25_SSSID_SPARE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
198 skb_pull(skb, AX25_KISS_HEADER_LEN);
199
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700200 if (digipeat != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
202 kfree_skb(skb);
203 goto put;
204 }
205
206 skb = ourskb;
207 }
208
Arnaldo Carvalho de Melo29c4be52005-04-21 16:46:56 -0700209 ax25_queue_xmit(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211put:
Ralf Baechle DL5RB006f68b2006-07-03 19:30:18 -0700212 if (route)
213 ax25_put_route(route);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
YOSHIFUJI Hideaki528930b2007-02-09 23:24:31 +0900215 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216}
217
218#else /* INET */
219
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700220int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
221 unsigned short type, const void *daddr,
Eric Dumazet95c96172012-04-15 05:58:06 +0000222 const void *saddr, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223{
224 return -AX25_HEADER_LEN;
225}
226
227int ax25_rebuild_header(struct sk_buff *skb)
228{
229 return 1;
230}
231
232#endif
233
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700234const struct header_ops ax25_header_ops = {
235 .create = ax25_hard_header,
236 .rebuild = ax25_rebuild_header,
237};
238
Ralf Baechle70868ea2006-05-03 23:25:17 -0700239EXPORT_SYMBOL(ax25_hard_header);
240EXPORT_SYMBOL(ax25_rebuild_header);
Stephen Hemminger3b04ddd2007-10-09 01:40:57 -0700241EXPORT_SYMBOL(ax25_header_ops);
242