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