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/config.h>
27#include <linux/module.h>
28#include <linux/kernel.h>
29#include <linux/init.h>
30#include <linux/netdevice.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
39static const char version[] = KERN_INFO "ipddp.c:v0.01 8/28/97 Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n";
40
41static struct ipddp_route *ipddp_route_list;
42
43#ifdef CONFIG_IPDDP_ENCAP
44static int ipddp_mode = IPDDP_ENCAP;
45#else
46static int ipddp_mode = IPDDP_DECAP;
47#endif
48
49/* Index to functions, as function prototypes. */
50static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev);
51static struct net_device_stats *ipddp_get_stats(struct net_device *dev);
52static int ipddp_create(struct ipddp_route *new_rt);
53static int ipddp_delete(struct ipddp_route *rt);
54static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt);
55static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
56
57
58static int __init ipddp_init(struct net_device *dev)
59{
60	static unsigned version_printed;
61
62	SET_MODULE_OWNER(dev);
63
64	if (version_printed++ == 0)
65                printk(version);
66
67	/* Let the user now what mode we are in */
68	if(ipddp_mode == IPDDP_ENCAP)
69		printk("%s: Appletalk-IP Encap. mode by Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n",
70			dev->name);
71	if(ipddp_mode == IPDDP_DECAP)
72		printk("%s: Appletalk-IP Decap. mode by Jay Schulist <jschlst@samba.org>\n",
73			dev->name);
74
75	/* Fill in the device structure with ethernet-generic values. */
76        ether_setup(dev);
77
78	/* Initalize the device structure. */
79        dev->hard_start_xmit = ipddp_xmit;
80
81        dev->priv = kmalloc(sizeof(struct net_device_stats), GFP_KERNEL);
82        if(!dev->priv)
83                return -ENOMEM;
84        memset(dev->priv,0,sizeof(struct net_device_stats));
85
86        dev->get_stats      = ipddp_get_stats;
87        dev->do_ioctl       = ipddp_ioctl;
88
89        dev->type = ARPHRD_IPDDP;       	/* IP over DDP tunnel */
90        dev->mtu = 585;
91        dev->flags |= IFF_NOARP;
92
93        /*
94         *      The worst case header we will need is currently a
95         *      ethernet header (14 bytes) and a ddp header (sizeof ddpehdr+1)
96         *      We send over SNAP so that takes another 8 bytes.
97         */
98        dev->hard_header_len = 14+8+sizeof(struct ddpehdr)+1;
99
100        return 0;
101}
102
103/*
104 * Get the current statistics. This may be called with the card open or closed.
105 */
106static struct net_device_stats *ipddp_get_stats(struct net_device *dev)
107{
108        return dev->priv;
109}
110
111/*
112 * Transmit LLAP/ELAP frame using aarp_send_ddp.
113 */
114static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
115{
116	u32 paddr = ((struct rtable*)skb->dst)->rt_gateway;
117        struct ddpehdr *ddp;
118        struct ipddp_route *rt;
119        struct at_addr *our_addr;
120
121	/*
122         * Find appropriate route to use, based only on IP number.
123         */
124        for(rt = ipddp_route_list; rt != NULL; rt = rt->next)
125        {
126                if(rt->ip == paddr)
127                        break;
128        }
129        if(rt == NULL)
130                return 0;
131
132        our_addr = atalk_find_dev_addr(rt->dev);
133
134	if(ipddp_mode == IPDDP_DECAP)
135		/*
136		 * Pull off the excess room that should not be there.
137		 * This is due to a hard-header problem. This is the
138		 * quick fix for now though, till it breaks.
139		 */
140		skb_pull(skb, 35-(sizeof(struct ddpehdr)+1));
141
142	/* Create the Extended DDP header */
143	ddp = (struct ddpehdr *)skb->data;
144        ddp->deh_len = skb->len;
145        ddp->deh_hops = 1;
146        ddp->deh_pad = 0;
147        ddp->deh_sum = 0;
148
149	/*
150         * For Localtalk we need aarp_send_ddp to strip the
151         * long DDP header and place a shot DDP header on it.
152         */
153        if(rt->dev->type == ARPHRD_LOCALTLK)
154        {
155                ddp->deh_dnet  = 0;
156                ddp->deh_snet  = 0;
157        }
158        else
159        {
160                ddp->deh_dnet  = rt->at.s_net;
161                ddp->deh_snet  = our_addr->s_net;
162        }
163        ddp->deh_dnode = rt->at.s_node;
164        ddp->deh_snode = our_addr->s_node;
165        ddp->deh_dport = 72;
166        ddp->deh_sport = 72;
167
168        *((__u8 *)(ddp+1)) = 22;        	/* ddp type = IP */
169        *((__u16 *)ddp)=ntohs(*((__u16 *)ddp));	/* fix up length field */
170
171        skb->protocol = htons(ETH_P_ATALK);     /* Protocol has changed */
172
173	((struct net_device_stats *) dev->priv)->tx_packets++;
174        ((struct net_device_stats *) dev->priv)->tx_bytes+=skb->len;
175
176        if(aarp_send_ddp(rt->dev, skb, &rt->at, NULL) < 0)
177                dev_kfree_skb(skb);
178
179        return 0;
180}
181
182/*
183 * Create a routing entry. We first verify that the
184 * record does not already exist. If it does we return -EEXIST
185 */
186static int ipddp_create(struct ipddp_route *new_rt)
187{
188        struct ipddp_route *rt =(struct ipddp_route*) kmalloc(sizeof(*rt), GFP_KERNEL);
189
190        if (rt == NULL)
191                return -ENOMEM;
192
193        rt->ip = new_rt->ip;
194        rt->at = new_rt->at;
195        rt->next = NULL;
196        if ((rt->dev = atrtr_get_dev(&rt->at)) == NULL) {
197		kfree(rt);
198                return -ENETUNREACH;
199        }
200
201	if (ipddp_find_route(rt)) {
202		kfree(rt);
203		return -EEXIST;
204	}
205
206        rt->next = ipddp_route_list;
207        ipddp_route_list = rt;
208
209        return 0;
210}
211
212/*
213 * Delete a route, we only delete a FULL match.
214 * If route does not exist we return -ENOENT.
215 */
216static int ipddp_delete(struct ipddp_route *rt)
217{
218        struct ipddp_route **r = &ipddp_route_list;
219        struct ipddp_route *tmp;
220
221        while((tmp = *r) != NULL)
222        {
223                if(tmp->ip == rt->ip
224                        && tmp->at.s_net == rt->at.s_net
225                        && tmp->at.s_node == rt->at.s_node)
226                {
227                        *r = tmp->next;
228                        kfree(tmp);
229                        return 0;
230                }
231                r = &tmp->next;
232        }
233
234        return (-ENOENT);
235}
236
237/*
238 * Find a routing entry, we only return a FULL match
239 */
240static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt)
241{
242        struct ipddp_route *f;
243
244        for(f = ipddp_route_list; f != NULL; f = f->next)
245        {
246                if(f->ip == rt->ip
247                        && f->at.s_net == rt->at.s_net
248                        && f->at.s_node == rt->at.s_node)
249                        return (f);
250        }
251
252        return (NULL);
253}
254
255static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
256{
257        struct ipddp_route *rt = (struct ipddp_route *)ifr->ifr_data;
258        struct ipddp_route rcp;
259
260        if(!capable(CAP_NET_ADMIN))
261                return -EPERM;
262
263	if(copy_from_user(&rcp, rt, sizeof(rcp)))
264		return -EFAULT;
265
266        switch(cmd)
267        {
268		case SIOCADDIPDDPRT:
269                        return (ipddp_create(&rcp));
270
271                case SIOCFINDIPDDPRT:
272                        if(copy_to_user(rt, ipddp_find_route(&rcp), sizeof(struct ipddp_route)))
273                                return -EFAULT;
274                        return 0;
275
276                case SIOCDELIPDDPRT:
277                        return (ipddp_delete(&rcp));
278
279                default:
280                        return -EINVAL;
281        }
282}
283
284static struct net_device dev_ipddp;
285
286MODULE_LICENSE("GPL");
287MODULE_PARM(ipddp_mode, "i");
288
289static int __init ipddp_init_module(void)
290{
291	int err;
292
293	dev_ipddp.init = ipddp_init;
294	err=dev_alloc_name(&dev_ipddp, "ipddp%d");
295        if(err < 0)
296                return err;
297
298	if(register_netdev(&dev_ipddp) != 0)
299                return -EIO;
300
301	return 0;
302}
303
304static void __exit ipddp_cleanup_module(void)
305{
306        struct ipddp_route *p;
307
308	unregister_netdev(&dev_ipddp);
309        kfree(dev_ipddp.priv);
310
311        while (ipddp_route_list) {
312                p = ipddp_route_list->next;
313                kfree(ipddp_route_list);
314                ipddp_route_list = p;
315        }
316}
317
318module_init(ipddp_init_module);
319module_exit(ipddp_cleanup_module);
320