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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 */
9#include <linux/config.h>
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/socket.h>
13#include <linux/in.h>
14#include <linux/kernel.h>
15#include <linux/sched.h>
16#include <linux/timer.h>
17#include <linux/string.h>
18#include <linux/sockios.h>
19#include <linux/net.h>
20#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>
27#include <asm/system.h>
28#include <linux/fcntl.h>
29#include <linux/termios.h> /* For TIOCINQ/OUTQ */
30#include <linux/mm.h>
31#include <linux/interrupt.h>
32#include <linux/notifier.h>
33#include <linux/proc_fs.h>
34#include <linux/stat.h>
35#include <linux/netfilter.h>
36#include <linux/sysctl.h>
37#include <net/ip.h>
38#include <net/arp.h>
39
40/*
41 * IP over AX.25 encapsulation.
42 */
43
44/*
45 * Shove an AX.25 UI header on an IP packet and handle ARP
46 */
47
48#ifdef CONFIG_INET
49
50int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
51{
52 unsigned char *buff;
53
54 /* they sometimes come back to us... */
55 if (type == ETH_P_AX25)
56 return 0;
57
58 /* header is an AX.25 UI frame from us to them */
59 buff = skb_push(skb, AX25_HEADER_LEN);
60 *buff++ = 0x00; /* KISS DATA */
61
62 if (daddr != NULL)
63 memcpy(buff, daddr, dev->addr_len); /* Address specified */
64
65 buff[6] &= ~AX25_CBIT;
66 buff[6] &= ~AX25_EBIT;
67 buff[6] |= AX25_SSSID_SPARE;
68 buff += AX25_ADDR_LEN;
69
70 if (saddr != NULL)
71 memcpy(buff, saddr, dev->addr_len);
72 else
73 memcpy(buff, dev->dev_addr, dev->addr_len);
74
75 buff[6] &= ~AX25_CBIT;
76 buff[6] |= AX25_EBIT;
77 buff[6] |= AX25_SSSID_SPARE;
78 buff += AX25_ADDR_LEN;
79
80 *buff++ = AX25_UI; /* UI */
81
82 /* Append a suitable AX.25 PID */
83 switch (type) {
84 case ETH_P_IP:
85 *buff++ = AX25_P_IP;
86 break;
87 case ETH_P_ARP:
88 *buff++ = AX25_P_ARP;
89 break;
90 default:
91 printk(KERN_ERR "AX.25: ax25_encapsulate - wrong protocol type 0x%2.2x\n", type);
92 *buff++ = 0;
93 break;
94 }
95
96 if (daddr != NULL)
97 return AX25_HEADER_LEN;
98
99 return -AX25_HEADER_LEN; /* Unfinished header */
100}
101
102int ax25_rebuild_header(struct sk_buff *skb)
103{
104 struct sk_buff *ourskb;
105 unsigned char *bp = skb->data;
106 struct net_device *dev;
107 ax25_address *src, *dst;
108 ax25_dev *ax25_dev;
109 ax25_route _route, *route = &_route;
110 ax25_cb *ax25;
111
112 dst = (ax25_address *)(bp + 1);
113 src = (ax25_address *)(bp + 8);
114
115 if (arp_find(bp + 1, skb))
116 return 1;
117
118 route = ax25_rt_find_route(route, dst, NULL);
119 dev = route->dev;
120
121 if (dev == NULL)
122 dev = skb->dev;
123
124 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
125 goto put;
126 }
127
128 if (bp[16] == AX25_P_IP) {
129 if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
130 /*
131 * We copy the buffer and release the original thereby
132 * keeping it straight
133 *
134 * Note: we report 1 back so the caller will
135 * not feed the frame direct to the physical device
136 * We don't want that to happen. (It won't be upset
137 * as we have pulled the frame from the queue by
138 * freeing it).
139 *
140 * NB: TCP modifies buffers that are still
141 * on a device queue, thus we use skb_copy()
142 * instead of using skb_clone() unless this
143 * gets fixed.
144 */
145
146 ax25_address src_c;
147 ax25_address dst_c;
148
149 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
150 kfree_skb(skb);
151 goto put;
152 }
153
154 if (skb->sk != NULL)
155 skb_set_owner_w(ourskb, skb->sk);
156
157 kfree_skb(skb);
158 /* dl9sau: bugfix
159 * after kfree_skb(), dst and src which were pointer
160 * to bp which is part of skb->data would not be valid
161 * anymore hope that after skb_pull(ourskb, ..) our
162 * dsc_c and src_c will not become invalid
163 */
164 bp = ourskb->data;
165 dst_c = *(ax25_address *)(bp + 1);
166 src_c = *(ax25_address *)(bp + 8);
167
168 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
169 ourskb->nh.raw = ourskb->data;
170
171 ax25=ax25_send_frame(
172 ourskb,
173 ax25_dev->values[AX25_VALUES_PACLEN],
174 &src_c,
175 &dst_c, route->digipeat, dev);
176 if (ax25) {
177 ax25_cb_put(ax25);
178 }
179 goto put;
180 }
181 }
182
183 bp[7] &= ~AX25_CBIT;
184 bp[7] &= ~AX25_EBIT;
185 bp[7] |= AX25_SSSID_SPARE;
186
187 bp[14] &= ~AX25_CBIT;
188 bp[14] |= AX25_EBIT;
189 bp[14] |= AX25_SSSID_SPARE;
190
191 skb_pull(skb, AX25_KISS_HEADER_LEN);
192
193 if (route->digipeat != NULL) {
194 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
195 kfree_skb(skb);
196 goto put;
197 }
198
199 skb = ourskb;
200 }
201
Arnaldo Carvalho de Melo29c4be52005-04-21 16:46:56 -0700202 ax25_queue_xmit(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204put:
205 ax25_put_route(route);
206
207 return 1;
208}
209
210#else /* INET */
211
212int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
213{
214 return -AX25_HEADER_LEN;
215}
216
217int ax25_rebuild_header(struct sk_buff *skb)
218{
219 return 1;
220}
221
222#endif
223