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 <linux/slab.h>
35 #include <net/route.h>
36 #include <linux/uaccess.h>
37
38 #include "ipddp.h" /* Our stuff */
39
40 static const char version[] = KERN_INFO "ipddp.c:v0.01 8/28/97 Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n";
41
42 static struct ipddp_route *ipddp_route_list;
43 static DEFINE_SPINLOCK(ipddp_route_lock);
44
45 #ifdef CONFIG_IPDDP_ENCAP
46 static int ipddp_mode = IPDDP_ENCAP;
47 #else
48 static int ipddp_mode = IPDDP_DECAP;
49 #endif
50
51 /* Index to functions, as function prototypes. */
52 static netdev_tx_t ipddp_xmit(struct sk_buff *skb,
53 struct net_device *dev);
54 static int ipddp_create(struct ipddp_route *new_rt);
55 static int ipddp_delete(struct ipddp_route *rt);
56 static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt);
57 static int ipddp_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
58 void __user *data, int cmd);
59
60 static const struct net_device_ops ipddp_netdev_ops = {
61 .ndo_start_xmit = ipddp_xmit,
62 .ndo_siocdevprivate = ipddp_siocdevprivate,
63 .ndo_set_mac_address = eth_mac_addr,
64 .ndo_validate_addr = eth_validate_addr,
65 };
66
ipddp_init(void)67 static struct net_device * __init ipddp_init(void)
68 {
69 static unsigned version_printed;
70 struct net_device *dev;
71 int err;
72
73 dev = alloc_etherdev(0);
74 if (!dev)
75 return ERR_PTR(-ENOMEM);
76
77 netif_keep_dst(dev);
78 strcpy(dev->name, "ipddp%d");
79
80 if (version_printed++ == 0)
81 printk(version);
82
83 /* Initialize the device structure. */
84 dev->netdev_ops = &ipddp_netdev_ops;
85
86 dev->type = ARPHRD_IPDDP; /* IP over DDP tunnel */
87 dev->mtu = 585;
88 dev->flags |= IFF_NOARP;
89
90 /*
91 * The worst case header we will need is currently a
92 * ethernet header (14 bytes) and a ddp header (sizeof ddpehdr+1)
93 * We send over SNAP so that takes another 8 bytes.
94 */
95 dev->hard_header_len = 14+8+sizeof(struct ddpehdr)+1;
96
97 err = register_netdev(dev);
98 if (err) {
99 free_netdev(dev);
100 return ERR_PTR(err);
101 }
102
103 /* Let the user now what mode we are in */
104 if(ipddp_mode == IPDDP_ENCAP)
105 printk("%s: Appletalk-IP Encap. mode by Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n",
106 dev->name);
107 if(ipddp_mode == IPDDP_DECAP)
108 printk("%s: Appletalk-IP Decap. mode by Jay Schulist <jschlst@samba.org>\n",
109 dev->name);
110
111 return dev;
112 }
113
114
115 /*
116 * Transmit LLAP/ELAP frame using aarp_send_ddp.
117 */
ipddp_xmit(struct sk_buff * skb,struct net_device * dev)118 static netdev_tx_t ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
119 {
120 struct rtable *rtable = skb_rtable(skb);
121 __be32 paddr = 0;
122 struct ddpehdr *ddp;
123 struct ipddp_route *rt;
124 struct atalk_addr *our_addr;
125
126 if (rtable->rt_gw_family == AF_INET)
127 paddr = rtable->rt_gw4;
128
129 spin_lock(&ipddp_route_lock);
130
131 /*
132 * Find appropriate route to use, based only on IP number.
133 */
134 for(rt = ipddp_route_list; rt != NULL; rt = rt->next)
135 {
136 if(rt->ip == paddr)
137 break;
138 }
139 if(rt == NULL) {
140 spin_unlock(&ipddp_route_lock);
141 return NETDEV_TX_OK;
142 }
143
144 our_addr = atalk_find_dev_addr(rt->dev);
145
146 if(ipddp_mode == IPDDP_DECAP)
147 /*
148 * Pull off the excess room that should not be there.
149 * This is due to a hard-header problem. This is the
150 * quick fix for now though, till it breaks.
151 */
152 skb_pull(skb, 35-(sizeof(struct ddpehdr)+1));
153
154 /* Create the Extended DDP header */
155 ddp = (struct ddpehdr *)skb->data;
156 ddp->deh_len_hops = htons(skb->len + (1<<10));
157 ddp->deh_sum = 0;
158
159 /*
160 * For Localtalk we need aarp_send_ddp to strip the
161 * long DDP header and place a shot DDP header on it.
162 */
163 if(rt->dev->type == ARPHRD_LOCALTLK)
164 {
165 ddp->deh_dnet = 0; /* FIXME more hops?? */
166 ddp->deh_snet = 0;
167 }
168 else
169 {
170 ddp->deh_dnet = rt->at.s_net; /* FIXME more hops?? */
171 ddp->deh_snet = our_addr->s_net;
172 }
173 ddp->deh_dnode = rt->at.s_node;
174 ddp->deh_snode = our_addr->s_node;
175 ddp->deh_dport = 72;
176 ddp->deh_sport = 72;
177
178 *((__u8 *)(ddp+1)) = 22; /* ddp type = IP */
179
180 skb->protocol = htons(ETH_P_ATALK); /* Protocol has changed */
181
182 dev->stats.tx_packets++;
183 dev->stats.tx_bytes += skb->len;
184
185 aarp_send_ddp(rt->dev, skb, &rt->at, NULL);
186
187 spin_unlock(&ipddp_route_lock);
188
189 return NETDEV_TX_OK;
190 }
191
192 /*
193 * Create a routing entry. We first verify that the
194 * record does not already exist. If it does we return -EEXIST
195 */
ipddp_create(struct ipddp_route * new_rt)196 static int ipddp_create(struct ipddp_route *new_rt)
197 {
198 struct ipddp_route *rt = kzalloc(sizeof(*rt), GFP_KERNEL);
199
200 if (rt == NULL)
201 return -ENOMEM;
202
203 rt->ip = new_rt->ip;
204 rt->at = new_rt->at;
205 rt->next = NULL;
206 if ((rt->dev = atrtr_get_dev(&rt->at)) == NULL) {
207 kfree(rt);
208 return -ENETUNREACH;
209 }
210
211 spin_lock_bh(&ipddp_route_lock);
212 if (__ipddp_find_route(rt)) {
213 spin_unlock_bh(&ipddp_route_lock);
214 kfree(rt);
215 return -EEXIST;
216 }
217
218 rt->next = ipddp_route_list;
219 ipddp_route_list = rt;
220
221 spin_unlock_bh(&ipddp_route_lock);
222
223 return 0;
224 }
225
226 /*
227 * Delete a route, we only delete a FULL match.
228 * If route does not exist we return -ENOENT.
229 */
ipddp_delete(struct ipddp_route * rt)230 static int ipddp_delete(struct ipddp_route *rt)
231 {
232 struct ipddp_route **r = &ipddp_route_list;
233 struct ipddp_route *tmp;
234
235 spin_lock_bh(&ipddp_route_lock);
236 while((tmp = *r) != NULL)
237 {
238 if(tmp->ip == rt->ip &&
239 tmp->at.s_net == rt->at.s_net &&
240 tmp->at.s_node == rt->at.s_node)
241 {
242 *r = tmp->next;
243 spin_unlock_bh(&ipddp_route_lock);
244 kfree(tmp);
245 return 0;
246 }
247 r = &tmp->next;
248 }
249
250 spin_unlock_bh(&ipddp_route_lock);
251 return -ENOENT;
252 }
253
254 /*
255 * Find a routing entry, we only return a FULL match
256 */
__ipddp_find_route(struct ipddp_route * rt)257 static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt)
258 {
259 struct ipddp_route *f;
260
261 for(f = ipddp_route_list; f != NULL; f = f->next)
262 {
263 if(f->ip == rt->ip &&
264 f->at.s_net == rt->at.s_net &&
265 f->at.s_node == rt->at.s_node)
266 return f;
267 }
268
269 return NULL;
270 }
271
ipddp_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * data,int cmd)272 static int ipddp_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
273 void __user *data, int cmd)
274 {
275 struct ipddp_route rcp, rcp2, *rp;
276
277 if (in_compat_syscall())
278 return -EOPNOTSUPP;
279
280 if(!capable(CAP_NET_ADMIN))
281 return -EPERM;
282
283 if (copy_from_user(&rcp, data, sizeof(rcp)))
284 return -EFAULT;
285
286 switch(cmd)
287 {
288 case SIOCADDIPDDPRT:
289 return ipddp_create(&rcp);
290
291 case SIOCFINDIPDDPRT:
292 spin_lock_bh(&ipddp_route_lock);
293 rp = __ipddp_find_route(&rcp);
294 if (rp) {
295 memset(&rcp2, 0, sizeof(rcp2));
296 rcp2.ip = rp->ip;
297 rcp2.at = rp->at;
298 rcp2.flags = rp->flags;
299 }
300 spin_unlock_bh(&ipddp_route_lock);
301
302 if (rp) {
303 if (copy_to_user(data, &rcp2,
304 sizeof(struct ipddp_route)))
305 return -EFAULT;
306 return 0;
307 } else
308 return -ENOENT;
309
310 case SIOCDELIPDDPRT:
311 return ipddp_delete(&rcp);
312
313 default:
314 return -EINVAL;
315 }
316 }
317
318 static struct net_device *dev_ipddp;
319
320 MODULE_LICENSE("GPL");
321 module_param(ipddp_mode, int, 0);
322
ipddp_init_module(void)323 static int __init ipddp_init_module(void)
324 {
325 dev_ipddp = ipddp_init();
326 return PTR_ERR_OR_ZERO(dev_ipddp);
327 }
328
ipddp_cleanup_module(void)329 static void __exit ipddp_cleanup_module(void)
330 {
331 struct ipddp_route *p;
332
333 unregister_netdev(dev_ipddp);
334 free_netdev(dev_ipddp);
335
336 while (ipddp_route_list) {
337 p = ipddp_route_list->next;
338 kfree(ipddp_route_list);
339 ipddp_route_list = p;
340 }
341 }
342
343 module_init(ipddp_init_module);
344 module_exit(ipddp_cleanup_module);
345
