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 <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
  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         /* Initalize 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  */
 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  */
 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  */
 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  */
 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
 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
 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
 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);