1 /*
2 * AX.25 release 037
3 *
4 * This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * History
13 * AX.25 036 Jonathan(G4KLX) Split from af_ax25.c.
14 */
15
16 #include <linux/config.h>
17 #include <linux/errno.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
20 #include <linux/in.h>
21 #include <linux/kernel.h>
22 #include <linux/sched.h>
23 #include <linux/timer.h>
24 #include <linux/string.h>
25 #include <linux/sockios.h>
26 #include <linux/net.h>
27 #include <net/ax25.h>
28 #include <linux/inet.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/skbuff.h>
32 #include <net/sock.h>
33 #include <asm/uaccess.h>
34 #include <asm/system.h>
35 #include <linux/fcntl.h>
36 #include <linux/termios.h> /* For TIOCINQ/OUTQ */
37 #include <linux/mm.h>
38 #include <linux/interrupt.h>
39 #include <linux/notifier.h>
40 #include <linux/proc_fs.h>
41 #include <linux/stat.h>
42 #include <linux/netfilter.h>
43 #include <linux/sysctl.h>
44 #include <net/ip.h>
45 #include <net/arp.h>
46
47 /*
48 * IP over AX.25 encapsulation.
49 */
50
51 /*
52 * Shove an AX.25 UI header on an IP packet and handle ARP
53 */
54
55 #ifdef CONFIG_INET
56
ax25_encapsulate(struct sk_buff * skb,struct net_device * dev,unsigned short type,void * daddr,void * saddr,unsigned len)57 int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
58 {
59 unsigned char *buff;
60
61 /* they sometimes come back to us... */
62 if (type == ETH_P_AX25)
63 return 0;
64
65 /* header is an AX.25 UI frame from us to them */
66 buff = skb_push(skb, AX25_HEADER_LEN);
67 *buff++ = 0x00; /* KISS DATA */
68
69 if (daddr != NULL)
70 memcpy(buff, daddr, dev->addr_len); /* Address specified */
71
72 buff[6] &= ~AX25_CBIT;
73 buff[6] &= ~AX25_EBIT;
74 buff[6] |= AX25_SSSID_SPARE;
75 buff += AX25_ADDR_LEN;
76
77 if (saddr != NULL)
78 memcpy(buff, saddr, dev->addr_len);
79 else
80 memcpy(buff, dev->dev_addr, dev->addr_len);
81
82 buff[6] &= ~AX25_CBIT;
83 buff[6] |= AX25_EBIT;
84 buff[6] |= AX25_SSSID_SPARE;
85 buff += AX25_ADDR_LEN;
86
87 *buff++ = AX25_UI; /* UI */
88
89 /* Append a suitable AX.25 PID */
90 switch (type) {
91 case ETH_P_IP:
92 *buff++ = AX25_P_IP;
93 break;
94 case ETH_P_ARP:
95 *buff++ = AX25_P_ARP;
96 break;
97 default:
98 printk(KERN_ERR "AX.25: ax25_encapsulate - wrong protocol type 0x%2.2x\n", type);
99 *buff++ = 0;
100 break;
101 }
102
103 if (daddr != NULL)
104 return AX25_HEADER_LEN;
105
106 return -AX25_HEADER_LEN; /* Unfinished header */
107 }
108
ax25_rebuild_header(struct sk_buff * skb)109 int ax25_rebuild_header(struct sk_buff *skb)
110 {
111 struct sk_buff *ourskb;
112 unsigned char *bp = skb->data;
113 struct net_device *dev;
114 ax25_address *src, *dst;
115 ax25_route *route;
116 ax25_dev *ax25_dev;
117
118 dst = (ax25_address *)(bp + 1);
119 src = (ax25_address *)(bp + 8);
120
121 if (arp_find(bp + 1, skb))
122 return 1;
123
124 route = ax25_rt_find_route(dst, NULL);
125 dev = route->dev;
126
127 if (dev == NULL)
128 dev = skb->dev;
129
130 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
131 return 1;
132
133 if (bp[16] == AX25_P_IP) {
134 if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
135 /*
136 * We copy the buffer and release the original thereby
137 * keeping it straight
138 *
139 * Note: we report 1 back so the caller will
140 * not feed the frame direct to the physical device
141 * We don't want that to happen. (It won't be upset
142 * as we have pulled the frame from the queue by
143 * freeing it).
144 *
145 * NB: TCP modifies buffers that are still
146 * on a device queue, thus we use skb_copy()
147 * instead of using skb_clone() unless this
148 * gets fixed.
149 */
150
151 ax25_address src_c;
152 ax25_address dst_c;
153
154 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
155 kfree_skb(skb);
156 return 1;
157 }
158
159 if (skb->sk != NULL)
160 skb_set_owner_w(ourskb, skb->sk);
161
162 kfree_skb(skb);
163 /* dl9sau: bugfix
164 * after kfree_skb(), dst and src which were pointer
165 * to bp which is part of skb->data would not be valid
166 * anymore hope that after skb_pull(ourskb, ..) our
167 * dsc_c and src_c will not become invalid
168 */
169 bp = ourskb->data;
170 dst_c = *(ax25_address *)(bp + 1);
171 src_c = *(ax25_address *)(bp + 8);
172
173 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
174 ourskb->nh.raw = ourskb->data;
175
176 ax25_send_frame(ourskb, ax25_dev->values[AX25_VALUES_PACLEN], &src_c,
177 &dst_c, route->digipeat, dev);
178
179 return 1;
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 return 1;
197 }
198
199 skb = ourskb;
200 }
201
202 skb->dev = dev;
203
204 ax25_queue_xmit(skb);
205
206 return 1;
207 }
208
209 #else /* INET */
210
ax25_encapsulate(struct sk_buff * skb,struct net_device * dev,unsigned short type,void * daddr,void * saddr,unsigned len)211 int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)
212 {
213 return -AX25_HEADER_LEN;
214 }
215
ax25_rebuild_header(struct sk_buff * skb)216 int ax25_rebuild_header(struct sk_buff *skb)
217 {
218 return 1;
219 }
220
221 #endif
222
223