1 /*
2 * ipddp.c: IP to Appletalk-IP Encapsulation driver for Linux
3 * Appletalk-IP to IP Decapsulation driver for Linux
4 *
5 * Authors:
6 * - DDP-IP Encap by: Bradford W. Johnson <johns393@maroon.tc.umn.edu>
7 * - DDP-IP Decap by: Jay Schulist <jschlst@samba.org>
8 *
9 * Derived from:
10 * - Almost all code already existed in net/appletalk/ddp.c I just
11 * moved/reorginized it into a driver file. Original IP-over-DDP code
12 * was done by Bradford W. Johnson <johns393@maroon.tc.umn.edu>
13 * - skeleton.c: A network driver outline for linux.
14 * Written 1993-94 by Donald Becker.
15 * - dummy.c: A dummy net driver. By Nick Holloway.
16 * - MacGate: A user space Daemon for Appletalk-IP Decap for
17 * Linux by Jay Schulist <jschlst@samba.org>
18 *
19 * Copyright 1993 United States Government as represented by the
20 * Director, National Security Agency.
21 *
22 * This software may be used and distributed according to the terms
23 * of the GNU General Public License, incorporated herein by reference.
24 */
25
26 #include <linux/module.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/netdevice.h>
30 #include <linux/etherdevice.h>
31 #include <linux/ip.h>
32 #include <linux/atalk.h>
33 #include <linux/if_arp.h>
34 #include <net/route.h>
35 #include <asm/uaccess.h>
36
37 #include "ipddp.h" /* Our stuff */
38
39 static const char version[] = KERN_INFO "ipddp.c:v0.01 8/28/97 Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n";
40
41 static struct ipddp_route *ipddp_route_list;
42 static DEFINE_SPINLOCK(ipddp_route_lock);
43
44 #ifdef CONFIG_IPDDP_ENCAP
45 static int ipddp_mode = IPDDP_ENCAP;
46 #else
47 static int ipddp_mode = IPDDP_DECAP;
48 #endif
49
50 /* Index to functions, as function prototypes. */
51 static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev);
52 static int ipddp_create(struct ipddp_route *new_rt);
53 static int ipddp_delete(struct ipddp_route *rt);
54 static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt);
55 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
56
57 static const struct net_device_ops ipddp_netdev_ops = {
58 .ndo_start_xmit = ipddp_xmit,
59 .ndo_do_ioctl = ipddp_ioctl,
60 .ndo_change_mtu = eth_change_mtu,
61 .ndo_set_mac_address = eth_mac_addr,
62 .ndo_validate_addr = eth_validate_addr,
63 };
64
65 static struct net_device * __init ipddp_init(void)
66 {
67 static unsigned version_printed;
68 struct net_device *dev;
69 int err;
70
71 dev = alloc_etherdev(0);
72 if (!dev)
73 return ERR_PTR(-ENOMEM);
74
75 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
76 strcpy(dev->name, "ipddp%d");
77
78 if (version_printed++ == 0)
79 printk(version);
80
81 /* Initalize the device structure. */
82 dev->netdev_ops = &ipddp_netdev_ops;
83
84 dev->type = ARPHRD_IPDDP; /* IP over DDP tunnel */
85 dev->mtu = 585;
86 dev->flags |= IFF_NOARP;
87
88 /*
89 * The worst case header we will need is currently a
90 * ethernet header (14 bytes) and a ddp header (sizeof ddpehdr+1)
91 * We send over SNAP so that takes another 8 bytes.
92 */
93 dev->hard_header_len = 14+8+sizeof(struct ddpehdr)+1;
94
95 err = register_netdev(dev);
96 if (err) {
97 free_netdev(dev);
98 return ERR_PTR(err);
99 }
100
101 /* Let the user now what mode we are in */
102 if(ipddp_mode == IPDDP_ENCAP)
103 printk("%s: Appletalk-IP Encap. mode by Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n",
104 dev->name);
105 if(ipddp_mode == IPDDP_DECAP)
106 printk("%s: Appletalk-IP Decap. mode by Jay Schulist <jschlst@samba.org>\n",
107 dev->name);
108
109 return dev;
110 }
111
112
113 /*
114 * Transmit LLAP/ELAP frame using aarp_send_ddp.
115 */
116 static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
117 {
118 __be32 paddr = skb_rtable(skb)->rt_gateway;
119 struct ddpehdr *ddp;
120 struct ipddp_route *rt;
121 struct atalk_addr *our_addr;
122
123 spin_lock(&ipddp_route_lock);
124
125 /*
126 * Find appropriate route to use, based only on IP number.
127 */
128 for(rt = ipddp_route_list; rt != NULL; rt = rt->next)
129 {
130 if(rt->ip == paddr)
131 break;
132 }
133 if(rt == NULL) {
134 spin_unlock(&ipddp_route_lock);
135 return 0;
136 }
137
138 our_addr = atalk_find_dev_addr(rt->dev);
139
140 if(ipddp_mode == IPDDP_DECAP)
141 /*
142 * Pull off the excess room that should not be there.
143 * This is due to a hard-header problem. This is the
144 * quick fix for now though, till it breaks.
145 */
146 skb_pull(skb, 35-(sizeof(struct ddpehdr)+1));
147
148 /* Create the Extended DDP header */
149 ddp = (struct ddpehdr *)skb->data;
150 ddp->deh_len_hops = htons(skb->len + (1<<10));
151 ddp->deh_sum = 0;
152
153 /*
154 * For Localtalk we need aarp_send_ddp to strip the
155 * long DDP header and place a shot DDP header on it.
156 */
157 if(rt->dev->type == ARPHRD_LOCALTLK)
158 {
159 ddp->deh_dnet = 0; /* FIXME more hops?? */
160 ddp->deh_snet = 0;
161 }
162 else
163 {
164 ddp->deh_dnet = rt->at.s_net; /* FIXME more hops?? */
165 ddp->deh_snet = our_addr->s_net;
166 }
167 ddp->deh_dnode = rt->at.s_node;
168 ddp->deh_snode = our_addr->s_node;
169 ddp->deh_dport = 72;
170 ddp->deh_sport = 72;
171
172 *((__u8 *)(ddp+1)) = 22; /* ddp type = IP */
173
174 skb->protocol = htons(ETH_P_ATALK); /* Protocol has changed */
175
176 dev->stats.tx_packets++;
177 dev->stats.tx_bytes += skb->len;
178
179 aarp_send_ddp(rt->dev, skb, &rt->at, NULL);
180
181 spin_unlock(&ipddp_route_lock);
182
183 return 0;
184 }
185
186 /*
187 * Create a routing entry. We first verify that the
188 * record does not already exist. If it does we return -EEXIST
189 */
190 static int ipddp_create(struct ipddp_route *new_rt)
191 {
192 struct ipddp_route *rt = kmalloc(sizeof(*rt), GFP_KERNEL);
193
194 if (rt == NULL)
195 return -ENOMEM;
196
197 rt->ip = new_rt->ip;
198 rt->at = new_rt->at;
199 rt->next = NULL;
200 if ((rt->dev = atrtr_get_dev(&rt->at)) == NULL) {
201 kfree(rt);
202 return -ENETUNREACH;
203 }
204
205 spin_lock_bh(&ipddp_route_lock);
206 if (__ipddp_find_route(rt)) {
207 spin_unlock_bh(&ipddp_route_lock);
208 kfree(rt);
209 return -EEXIST;
210 }
211
212 rt->next = ipddp_route_list;
213 ipddp_route_list = rt;
214
215 spin_unlock_bh(&ipddp_route_lock);
216
217 return 0;
218 }
219
220 /*
221 * Delete a route, we only delete a FULL match.
222 * If route does not exist we return -ENOENT.
223 */
224 static int ipddp_delete(struct ipddp_route *rt)
225 {
226 struct ipddp_route **r = &ipddp_route_list;
227 struct ipddp_route *tmp;
228
229 spin_lock_bh(&ipddp_route_lock);
230 while((tmp = *r) != NULL)
231 {
232 if(tmp->ip == rt->ip
233 && tmp->at.s_net == rt->at.s_net
234 && tmp->at.s_node == rt->at.s_node)
235 {
236 *r = tmp->next;
237 spin_unlock_bh(&ipddp_route_lock);
238 kfree(tmp);
239 return 0;
240 }
241 r = &tmp->next;
242 }
243
244 spin_unlock_bh(&ipddp_route_lock);
245 return (-ENOENT);
246 }
247
248 /*
249 * Find a routing entry, we only return a FULL match
250 */
251 static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt)
252 {
253 struct ipddp_route *f;
254
255 for(f = ipddp_route_list; f != NULL; f = f->next)
256 {
257 if(f->ip == rt->ip
258 && f->at.s_net == rt->at.s_net
259 && f->at.s_node == rt->at.s_node)
260 return (f);
261 }
262
263 return (NULL);
264 }
265
266 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
267 {
268 struct ipddp_route __user *rt = ifr->ifr_data;
269 struct ipddp_route rcp, rcp2, *rp;
270
271 if(!capable(CAP_NET_ADMIN))
272 return -EPERM;
273
274 if(copy_from_user(&rcp, rt, sizeof(rcp)))
275 return -EFAULT;
276
277 switch(cmd)
278 {
279 case SIOCADDIPDDPRT:
280 return (ipddp_create(&rcp));
281
282 case SIOCFINDIPDDPRT:
283 spin_lock_bh(&ipddp_route_lock);
284 rp = __ipddp_find_route(&rcp);
285 if (rp)
286 memcpy(&rcp2, rp, sizeof(rcp2));
287 spin_unlock_bh(&ipddp_route_lock);
288
289 if (rp) {
290 if (copy_to_user(rt, &rcp2,
291 sizeof(struct ipddp_route)))
292 return -EFAULT;
293 return 0;
294 } else
295 return -ENOENT;
296
297 case SIOCDELIPDDPRT:
298 return (ipddp_delete(&rcp));
299
300 default:
301 return -EINVAL;
302 }
303 }
304
305 static struct net_device *dev_ipddp;
306
307 MODULE_LICENSE("GPL");
308 module_param(ipddp_mode, int, 0);
309
310 static int __init ipddp_init_module(void)
311 {
312 dev_ipddp = ipddp_init();
313 if (IS_ERR(dev_ipddp))
314 return PTR_ERR(dev_ipddp);
315 return 0;
316 }
317
318 static void __exit ipddp_cleanup_module(void)
319 {
320 struct ipddp_route *p;
321
322 unregister_netdev(dev_ipddp);
323 free_netdev(dev_ipddp);
324
325 while (ipddp_route_list) {
326 p = ipddp_route_list->next;
327 kfree(ipddp_route_list);
328 ipddp_route_list = p;
329 }
330 }
331
332 module_init(ipddp_init_module);
333 module_exit(ipddp_cleanup_module);
334
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