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 <asm/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_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
58
59 static const struct net_device_ops ipddp_netdev_ops = {
60 .ndo_start_xmit = ipddp_xmit,
61 .ndo_do_ioctl = ipddp_ioctl,
62 .ndo_change_mtu = eth_change_mtu,
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 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
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 __be32 paddr = skb_rtable(skb)->rt_gateway;
121 struct ddpehdr *ddp;
122 struct ipddp_route *rt;
123 struct atalk_addr *our_addr;
124
125 spin_lock(&ipddp_route_lock);
126
127 /*
128 * Find appropriate route to use, based only on IP number.
129 */
130 for(rt = ipddp_route_list; rt != NULL; rt = rt->next)
131 {
132 if(rt->ip == paddr)
133 break;
134 }
135 if(rt == NULL) {
136 spin_unlock(&ipddp_route_lock);
137 return NETDEV_TX_OK;
138 }
139
140 our_addr = atalk_find_dev_addr(rt->dev);
141
142 if(ipddp_mode == IPDDP_DECAP)
143 /*
144 * Pull off the excess room that should not be there.
145 * This is due to a hard-header problem. This is the
146 * quick fix for now though, till it breaks.
147 */
148 skb_pull(skb, 35-(sizeof(struct ddpehdr)+1));
149
150 /* Create the Extended DDP header */
151 ddp = (struct ddpehdr *)skb->data;
152 ddp->deh_len_hops = htons(skb->len + (1<<10));
153 ddp->deh_sum = 0;
154
155 /*
156 * For Localtalk we need aarp_send_ddp to strip the
157 * long DDP header and place a shot DDP header on it.
158 */
159 if(rt->dev->type == ARPHRD_LOCALTLK)
160 {
161 ddp->deh_dnet = 0; /* FIXME more hops?? */
162 ddp->deh_snet = 0;
163 }
164 else
165 {
166 ddp->deh_dnet = rt->at.s_net; /* FIXME more hops?? */
167 ddp->deh_snet = our_addr->s_net;
168 }
169 ddp->deh_dnode = rt->at.s_node;
170 ddp->deh_snode = our_addr->s_node;
171 ddp->deh_dport = 72;
172 ddp->deh_sport = 72;
173
174 *((__u8 *)(ddp+1)) = 22; /* ddp type = IP */
175
176 skb->protocol = htons(ETH_P_ATALK); /* Protocol has changed */
177
178 dev->stats.tx_packets++;
179 dev->stats.tx_bytes += skb->len;
180
181 aarp_send_ddp(rt->dev, skb, &rt->at, NULL);
182
183 spin_unlock(&ipddp_route_lock);
184
185 return NETDEV_TX_OK;
186 }
187
188 /*
189 * Create a routing entry. We first verify that the
190 * record does not already exist. If it does we return -EEXIST
191 */
ipddp_create(struct ipddp_route * new_rt)192 static int ipddp_create(struct ipddp_route *new_rt)
193 {
194 struct ipddp_route *rt = kmalloc(sizeof(*rt), GFP_KERNEL);
195
196 if (rt == NULL)
197 return -ENOMEM;
198
199 rt->ip = new_rt->ip;
200 rt->at = new_rt->at;
201 rt->next = NULL;
202 if ((rt->dev = atrtr_get_dev(&rt->at)) == NULL) {
203 kfree(rt);
204 return -ENETUNREACH;
205 }
206
207 spin_lock_bh(&ipddp_route_lock);
208 if (__ipddp_find_route(rt)) {
209 spin_unlock_bh(&ipddp_route_lock);
210 kfree(rt);
211 return -EEXIST;
212 }
213
214 rt->next = ipddp_route_list;
215 ipddp_route_list = rt;
216
217 spin_unlock_bh(&ipddp_route_lock);
218
219 return 0;
220 }
221
222 /*
223 * Delete a route, we only delete a FULL match.
224 * If route does not exist we return -ENOENT.
225 */
ipddp_delete(struct ipddp_route * rt)226 static int ipddp_delete(struct ipddp_route *rt)
227 {
228 struct ipddp_route **r = &ipddp_route_list;
229 struct ipddp_route *tmp;
230
231 spin_lock_bh(&ipddp_route_lock);
232 while((tmp = *r) != NULL)
233 {
234 if(tmp->ip == rt->ip &&
235 tmp->at.s_net == rt->at.s_net &&
236 tmp->at.s_node == rt->at.s_node)
237 {
238 *r = tmp->next;
239 spin_unlock_bh(&ipddp_route_lock);
240 kfree(tmp);
241 return 0;
242 }
243 r = &tmp->next;
244 }
245
246 spin_unlock_bh(&ipddp_route_lock);
247 return -ENOENT;
248 }
249
250 /*
251 * Find a routing entry, we only return a FULL match
252 */
__ipddp_find_route(struct ipddp_route * rt)253 static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt)
254 {
255 struct ipddp_route *f;
256
257 for(f = ipddp_route_list; f != NULL; f = f->next)
258 {
259 if(f->ip == rt->ip &&
260 f->at.s_net == rt->at.s_net &&
261 f->at.s_node == rt->at.s_node)
262 return f;
263 }
264
265 return NULL;
266 }
267
ipddp_ioctl(struct net_device * dev,struct ifreq * ifr,int cmd)268 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
269 {
270 struct ipddp_route __user *rt = ifr->ifr_data;
271 struct ipddp_route rcp, rcp2, *rp;
272
273 if(!capable(CAP_NET_ADMIN))
274 return -EPERM;
275
276 if(copy_from_user(&rcp, rt, sizeof(rcp)))
277 return -EFAULT;
278
279 switch(cmd)
280 {
281 case SIOCADDIPDDPRT:
282 return ipddp_create(&rcp);
283
284 case SIOCFINDIPDDPRT:
285 spin_lock_bh(&ipddp_route_lock);
286 rp = __ipddp_find_route(&rcp);
287 if (rp)
288 memcpy(&rcp2, rp, sizeof(rcp2));
289 spin_unlock_bh(&ipddp_route_lock);
290
291 if (rp) {
292 if (copy_to_user(rt, &rcp2,
293 sizeof(struct ipddp_route)))
294 return -EFAULT;
295 return 0;
296 } else
297 return -ENOENT;
298
299 case SIOCDELIPDDPRT:
300 return ipddp_delete(&rcp);
301
302 default:
303 return -EINVAL;
304 }
305 }
306
307 static struct net_device *dev_ipddp;
308
309 MODULE_LICENSE("GPL");
310 module_param(ipddp_mode, int, 0);
311
ipddp_init_module(void)312 static int __init ipddp_init_module(void)
313 {
314 dev_ipddp = ipddp_init();
315 if (IS_ERR(dev_ipddp))
316 return PTR_ERR(dev_ipddp);
317 return 0;
318 }
319
ipddp_cleanup_module(void)320 static void __exit ipddp_cleanup_module(void)
321 {
322 struct ipddp_route *p;
323
324 unregister_netdev(dev_ipddp);
325 free_netdev(dev_ipddp);
326
327 while (ipddp_route_list) {
328 p = ipddp_route_list->next;
329 kfree(ipddp_route_list);
330 ipddp_route_list = p;
331 }
332 }
333
334 module_init(ipddp_init_module);
335 module_exit(ipddp_cleanup_module);
336