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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>
Ralf Baechle70868ea2006-05-03 23:25:17 -070015#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/sched.h>
17#include <linux/timer.h>
18#include <linux/string.h>
19#include <linux/sockios.h>
20#include <linux/net.h>
21#include <net/ax25.h>
22#include <linux/inet.h>
23#include <linux/netdevice.h>
24#include <linux/if_arp.h>
25#include <linux/skbuff.h>
26#include <net/sock.h>
27#include <asm/uaccess.h>
28#include <asm/system.h>
29#include <linux/fcntl.h>
30#include <linux/termios.h> /* For TIOCINQ/OUTQ */
31#include <linux/mm.h>
32#include <linux/interrupt.h>
33#include <linux/notifier.h>
34#include <linux/proc_fs.h>
35#include <linux/stat.h>
36#include <linux/netfilter.h>
37#include <linux/sysctl.h>
38#include <net/ip.h>
39#include <net/arp.h>
40
41/*
42 * IP over AX.25 encapsulation.
43 */
44
45/*
46 * Shove an AX.25 UI header on an IP packet and handle ARP
47 */
48
49#ifdef CONFIG_INET
50
Ralf Baechle6f749982005-09-12 14:21:01 -070051int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned 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
59 /* header is an AX.25 UI frame from us to them */
60 buff = skb_push(skb, AX25_HEADER_LEN);
61 *buff++ = 0x00; /* KISS DATA */
62
63 if (daddr != NULL)
64 memcpy(buff, daddr, dev->addr_len); /* Address specified */
65
66 buff[6] &= ~AX25_CBIT;
67 buff[6] &= ~AX25_EBIT;
68 buff[6] |= AX25_SSSID_SPARE;
69 buff += AX25_ADDR_LEN;
70
71 if (saddr != NULL)
72 memcpy(buff, saddr, dev->addr_len);
73 else
74 memcpy(buff, dev->dev_addr, dev->addr_len);
75
76 buff[6] &= ~AX25_CBIT;
77 buff[6] |= AX25_EBIT;
78 buff[6] |= AX25_SSSID_SPARE;
79 buff += AX25_ADDR_LEN;
80
81 *buff++ = AX25_UI; /* UI */
82
83 /* 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:
Ralf Baechle6f749982005-09-12 14:21:01 -070092 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 *buff++ = 0;
94 break;
95 }
96
97 if (daddr != NULL)
98 return AX25_HEADER_LEN;
99
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;
107 struct net_device *dev;
108 ax25_address *src, *dst;
109 ax25_dev *ax25_dev;
110 ax25_route _route, *route = &_route;
111 ax25_cb *ax25;
112
113 dst = (ax25_address *)(bp + 1);
114 src = (ax25_address *)(bp + 8);
115
116 if (arp_find(bp + 1, skb))
117 return 1;
118
119 route = ax25_rt_find_route(route, dst, NULL);
120 dev = route->dev;
121
122 if (dev == NULL)
123 dev = skb->dev;
124
125 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
126 goto put;
127 }
128
129 if (bp[16] == AX25_P_IP) {
130 if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
131 /*
132 * We copy the buffer and release the original thereby
133 * keeping it straight
134 *
135 * Note: we report 1 back so the caller will
136 * not feed the frame direct to the physical device
137 * We don't want that to happen. (It won't be upset
138 * as we have pulled the frame from the queue by
139 * freeing it).
140 *
141 * NB: TCP modifies buffers that are still
142 * on a device queue, thus we use skb_copy()
143 * instead of using skb_clone() unless this
144 * gets fixed.
145 */
146
147 ax25_address src_c;
148 ax25_address dst_c;
149
150 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
151 kfree_skb(skb);
152 goto put;
153 }
154
155 if (skb->sk != NULL)
156 skb_set_owner_w(ourskb, skb->sk);
157
158 kfree_skb(skb);
159 /* dl9sau: bugfix
160 * after kfree_skb(), dst and src which were pointer
161 * to bp which is part of skb->data would not be valid
162 * anymore hope that after skb_pull(ourskb, ..) our
163 * dsc_c and src_c will not become invalid
164 */
165 bp = ourskb->data;
166 dst_c = *(ax25_address *)(bp + 1);
167 src_c = *(ax25_address *)(bp + 8);
168
169 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
170 ourskb->nh.raw = ourskb->data;
171
172 ax25=ax25_send_frame(
173 ourskb,
174 ax25_dev->values[AX25_VALUES_PACLEN],
175 &src_c,
176 &dst_c, route->digipeat, dev);
177 if (ax25) {
178 ax25_cb_put(ax25);
179 }
180 goto put;
181 }
182 }
183
184 bp[7] &= ~AX25_CBIT;
185 bp[7] &= ~AX25_EBIT;
186 bp[7] |= AX25_SSSID_SPARE;
187
188 bp[14] &= ~AX25_CBIT;
189 bp[14] |= AX25_EBIT;
190 bp[14] |= AX25_SSSID_SPARE;
191
192 skb_pull(skb, AX25_KISS_HEADER_LEN);
193
194 if (route->digipeat != NULL) {
195 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
196 kfree_skb(skb);
197 goto put;
198 }
199
200 skb = ourskb;
201 }
202
Arnaldo Carvalho de Melo29c4be52005-04-21 16:46:56 -0700203 ax25_queue_xmit(skb, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
205put:
206 ax25_put_route(route);
207
208 return 1;
209}
210
211#else /* INET */
212
Ralf Baechle6f749982005-09-12 14:21:01 -0700213int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
215 return -AX25_HEADER_LEN;
216}
217
218int ax25_rebuild_header(struct sk_buff *skb)
219{
220 return 1;
221}
222
223#endif
224
Ralf Baechle70868ea2006-05-03 23:25:17 -0700225EXPORT_SYMBOL(ax25_hard_header);
226EXPORT_SYMBOL(ax25_rebuild_header);