drivers/net/appletalk/ipddp.c

   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
  43 #ifdef CONFIG_IPDDP_ENCAP
  44 static int ipddp_mode = IPDDP_ENCAP;
  45 #else
  46 static int ipddp_mode = IPDDP_DECAP;
  47 #endif
  48
  49 /* Index to functions, as function prototypes. */
  50 static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev);
  51 static int ipddp_create(struct ipddp_route *new_rt);
  52 static int ipddp_delete(struct ipddp_route *rt);
  53 static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt);
  54 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
  55
  56 static const struct net_device_ops ipddp_netdev_ops = {
  57         .ndo_start_xmit         = ipddp_xmit,
  58         .ndo_do_ioctl           = ipddp_ioctl,
  59         .ndo_change_mtu         = eth_change_mtu,
  60         .ndo_set_mac_address    = eth_mac_addr,
  61         .ndo_validate_addr      = eth_validate_addr,
  62 };
  63
  64 static struct net_device * __init ipddp_init(void)
  65 {
  66         static unsigned version_printed;
  67         struct net_device *dev;
  68         int err;
  69
  70         dev = alloc_etherdev(0);
  71         if (!dev)
  72                 return ERR_PTR(-ENOMEM);
  73
  74         strcpy(dev->name, "ipddp%d");
  75
  76         if (version_printed++ == 0)
  77                 printk(version);
  78
  79         /* Initalize the device structure. */
  80         dev->netdev_ops = &ipddp_netdev_ops;
  81
  82         dev->type = ARPHRD_IPDDP;               /* IP over DDP tunnel */
  83         dev->mtu = 585;
  84         dev->flags |= IFF_NOARP;
  85
  86         /*
  87          *      The worst case header we will need is currently a
  88          *      ethernet header (14 bytes) and a ddp header (sizeof ddpehdr+1)
  89          *      We send over SNAP so that takes another 8 bytes.
  90          */
  91         dev->hard_header_len = 14+8+sizeof(struct ddpehdr)+1;
  92
  93         err = register_netdev(dev);
  94         if (err) {
  95                 free_netdev(dev);
  96                 return ERR_PTR(err);
  97         }
  98
  99         /* Let the user now what mode we are in */
 100         if(ipddp_mode == IPDDP_ENCAP)
 101                 printk("%s: Appletalk-IP Encap. mode by Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n",
 102                         dev->name);
 103         if(ipddp_mode == IPDDP_DECAP)
 104                 printk("%s: Appletalk-IP Decap. mode by Jay Schulist <jschlst@samba.org>\n",
 105                         dev->name);
 106
 107         return dev;
 108 }
 109
 110
 111 /*
 112  * Transmit LLAP/ELAP frame using aarp_send_ddp.
 113  */
 114 static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
 115 {
 116         __be32 paddr = ((struct rtable*)skb->dst)->rt_gateway;
 117         struct ddpehdr *ddp;
 118         struct ipddp_route *rt;
 119         struct atalk_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_hops = htons(skb->len + (1<<10));
 145         ddp->deh_sum = 0;
 146
 147         /*
 148          * For Localtalk we need aarp_send_ddp to strip the
 149          * long DDP header and place a shot DDP header on it.
 150          */
 151         if(rt->dev->type == ARPHRD_LOCALTLK)
 152         {
 153                 ddp->deh_dnet  = 0;   /* FIXME more hops?? */
 154                 ddp->deh_snet  = 0;
 155         }
 156         else
 157         {
 158                 ddp->deh_dnet  = rt->at.s_net;   /* FIXME more hops?? */
 159                 ddp->deh_snet  = our_addr->s_net;
 160         }
 161         ddp->deh_dnode = rt->at.s_node;
 162         ddp->deh_snode = our_addr->s_node;
 163         ddp->deh_dport = 72;
 164         ddp->deh_sport = 72;
 165
 166         *((__u8 *)(ddp+1)) = 22;                /* ddp type = IP */
 167
 168         skb->protocol = htons(ETH_P_ATALK);     /* Protocol has changed */
 169
 170         dev->stats.tx_packets++;
 171         dev->stats.tx_bytes += skb->len;
 172
 173         if(aarp_send_ddp(rt->dev, skb, &rt->at, NULL) < 0)
 174                 dev_kfree_skb(skb);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * Create a routing entry. We first verify that the
 181  * record does not already exist. If it does we return -EEXIST
 182  */
 183 static int ipddp_create(struct ipddp_route *new_rt)
 184 {
 185         struct ipddp_route *rt = kmalloc(sizeof(*rt), GFP_KERNEL);
 186
 187         if (rt == NULL)
 188                 return -ENOMEM;
 189
 190         rt->ip = new_rt->ip;
 191         rt->at = new_rt->at;
 192         rt->next = NULL;
 193         if ((rt->dev = atrtr_get_dev(&rt->at)) == NULL) {
 194                 kfree(rt);
 195                 return -ENETUNREACH;
 196         }
 197
 198         if (ipddp_find_route(rt)) {
 199                 kfree(rt);
 200                 return -EEXIST;
 201         }
 202
 203         rt->next = ipddp_route_list;
 204         ipddp_route_list = rt;
 205
 206         return 0;
 207 }
 208
 209 /*
 210  * Delete a route, we only delete a FULL match.
 211  * If route does not exist we return -ENOENT.
 212  */
 213 static int ipddp_delete(struct ipddp_route *rt)
 214 {
 215         struct ipddp_route **r = &ipddp_route_list;
 216         struct ipddp_route *tmp;
 217
 218         while((tmp = *r) != NULL)
 219         {
 220                 if(tmp->ip == rt->ip
 221                         && tmp->at.s_net == rt->at.s_net
 222                         && tmp->at.s_node == rt->at.s_node)
 223                 {
 224                         *r = tmp->next;
 225                         kfree(tmp);
 226                         return 0;
 227                 }
 228                 r = &tmp->next;
 229         }
 230
 231         return (-ENOENT);
 232 }
 233
 234 /*
 235  * Find a routing entry, we only return a FULL match
 236  */
 237 static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt)
 238 {
 239         struct ipddp_route *f;
 240
 241         for(f = ipddp_route_list; f != NULL; f = f->next)
 242         {
 243                 if(f->ip == rt->ip
 244                         && f->at.s_net == rt->at.s_net
 245                         && f->at.s_node == rt->at.s_node)
 246                         return (f);
 247         }
 248
 249         return (NULL);
 250 }
 251
 252 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 253 {
 254         struct ipddp_route __user *rt = ifr->ifr_data;
 255         struct ipddp_route rcp;
 256
 257         if(!capable(CAP_NET_ADMIN))
 258                 return -EPERM;
 259
 260         if(copy_from_user(&rcp, rt, sizeof(rcp)))
 261                 return -EFAULT;
 262
 263         switch(cmd)
 264         {
 265                 case SIOCADDIPDDPRT:
 266                         return (ipddp_create(&rcp));
 267
 268                 case SIOCFINDIPDDPRT:
 269                         if(copy_to_user(rt, ipddp_find_route(&rcp), sizeof(struct ipddp_route)))
 270                                 return -EFAULT;
 271                         return 0;
 272
 273                 case SIOCDELIPDDPRT:
 274                         return (ipddp_delete(&rcp));
 275
 276                 default:
 277                         return -EINVAL;
 278         }
 279 }
 280
 281 static struct net_device *dev_ipddp;
 282
 283 MODULE_LICENSE("GPL");
 284 module_param(ipddp_mode, int, 0);
 285
 286 static int __init ipddp_init_module(void)
 287 {
 288         dev_ipddp = ipddp_init();
 289         if (IS_ERR(dev_ipddp))
 290                 return PTR_ERR(dev_ipddp);
 291         return 0;
 292 }
 293
 294 static void __exit ipddp_cleanup_module(void)
 295 {
 296         struct ipddp_route *p;
 297
 298         unregister_netdev(dev_ipddp);
 299         free_netdev(dev_ipddp);
 300
 301         while (ipddp_route_list) {
 302                 p = ipddp_route_list->next;
 303                 kfree(ipddp_route_list);
 304                 ipddp_route_list = p;
 305         }
 306 }
 307
 308 module_init(ipddp_init_module);
 309 module_exit(ipddp_cleanup_module);