summaryrefslogtreecommitdiffstats
path: root/net/ax25/ax25_ip.c
blob: 8d62d86816150b9d814f1edc469f065c48a48b80 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/sysctl.h>
#include <net/ip.h>
#include <net/arp.h>

/*
 *	IP over AX.25 encapsulation.
 */

/*
 *	Shove an AX.25 UI header on an IP packet and handle ARP
 */

#ifdef CONFIG_INET

int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
{
	unsigned char *buff;

	/* they sometimes come back to us... */
	if (type == ETH_P_AX25)
		return 0;

	/* header is an AX.25 UI frame from us to them */
	buff = skb_push(skb, AX25_HEADER_LEN);
	*buff++ = 0x00;	/* KISS DATA */

	if (daddr != NULL)
		memcpy(buff, daddr, dev->addr_len);	/* Address specified */

	buff[6] &= ~AX25_CBIT;
	buff[6] &= ~AX25_EBIT;
	buff[6] |= AX25_SSSID_SPARE;
	buff    += AX25_ADDR_LEN;

	if (saddr != NULL)
		memcpy(buff, saddr, dev->addr_len);
	else
		memcpy(buff, dev->dev_addr, dev->addr_len);

	buff[6] &= ~AX25_CBIT;
	buff[6] |= AX25_EBIT;
	buff[6] |= AX25_SSSID_SPARE;
	buff    += AX25_ADDR_LEN;

	*buff++  = AX25_UI;	/* UI */

	/* Append a suitable AX.25 PID */
	switch (type) {
	case ETH_P_IP:
		*buff++ = AX25_P_IP;
		break;
	case ETH_P_ARP:
		*buff++ = AX25_P_ARP;
		break;
	default:
		printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
		*buff++ = 0;
		break;
	}

	if (daddr != NULL)
		return AX25_HEADER_LEN;

	return -AX25_HEADER_LEN;	/* Unfinished header */
}

int ax25_rebuild_header(struct sk_buff *skb)
{
	struct sk_buff *ourskb;
	unsigned char *bp  = skb->data;
	ax25_route *route;
	struct net_device *dev = NULL;
	ax25_address *src, *dst;
	ax25_digi *digipeat = NULL;
	ax25_dev *ax25_dev;
	ax25_cb *ax25;
	char ip_mode = ' ';

	dst = (ax25_address *)(bp + 1);
	src = (ax25_address *)(bp + 8);

	if (arp_find(bp + 1, skb))
		return 1;

	route = ax25_get_route(dst, NULL);
	if (route) {
		digipeat = route->digipeat;
		dev = route->dev;
		ip_mode = route->ip_mode;
	};

	if (dev == NULL)
		dev = skb->dev;

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
		goto put;
	}

	if (bp[16] == AX25_P_IP) {
		if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
			/*
			 *	We copy the buffer and release the original thereby
			 *	keeping it straight
			 *
			 *	Note: we report 1 back so the caller will
			 *	not feed the frame direct to the physical device
			 *	We don't want that to happen. (It won't be upset
			 *	as we have pulled the frame from the queue by
			 *	freeing it).
			 *
			 *	NB: TCP modifies buffers that are still
			 *	on a device queue, thus we use skb_copy()
			 *      instead of using skb_clone() unless this
			 *	gets fixed.
			 */

			ax25_address src_c;
			ax25_address dst_c;

			if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
				kfree_skb(skb);
				goto put;
			}

			if (skb->sk != NULL)
				skb_set_owner_w(ourskb, skb->sk);

			kfree_skb(skb);
			/* dl9sau: bugfix
			 * after kfree_skb(), dst and src which were pointer
			 * to bp which is part of skb->data would not be valid
			 * anymore hope that after skb_pull(ourskb, ..) our
			 * dsc_c and src_c will not become invalid
			 */
			bp  = ourskb->data;
			dst_c = *(ax25_address *)(bp + 1);
			src_c = *(ax25_address *)(bp + 8);

			skb_pull(ourskb, AX25_HEADER_LEN - 1);	/* Keep PID */
			ourskb->nh.raw = ourskb->data;

			ax25=ax25_send_frame(
			    ourskb,
			    ax25_dev->values[AX25_VALUES_PACLEN],
			    &src_c,
			    &dst_c, digipeat, dev);
			if (ax25) {
				ax25_cb_put(ax25);
			}
			goto put;
		}
	}

	bp[7]  &= ~AX25_CBIT;
	bp[7]  &= ~AX25_EBIT;
	bp[7]  |= AX25_SSSID_SPARE;

	bp[14] &= ~AX25_CBIT;
	bp[14] |= AX25_EBIT;
	bp[14] |= AX25_SSSID_SPARE;

	skb_pull(skb, AX25_KISS_HEADER_LEN);

	if (digipeat != NULL) {
		if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
			kfree_skb(skb);
			goto put;
		}

		skb = ourskb;
	}

	ax25_queue_xmit(skb, dev);

put:
	if (route)
		ax25_put_route(route);

	return 1;
}

#else	/* INET */

int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
{
	return -AX25_HEADER_LEN;
}

int ax25_rebuild_header(struct sk_buff *skb)
{
	return 1;
}

#endif

EXPORT_SYMBOL(ax25_hard_header);
EXPORT_SYMBOL(ax25_rebuild_header);