net/decnet/dn_rules.c

   1
   2 /*
   3  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   4  *              operating system.  DECnet is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              DECnet Routing Forwarding Information Base (Rules)
   8  *
   9  * Author:      Steve Whitehouse <SteveW@ACM.org>
  10  *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
  11  *
  12  *
  13  * Changes:
  14  *
  15  */
  16 #include <linux/config.h>
  17 #include <linux/string.h>
  18 #include <linux/net.h>
  19 #include <linux/socket.h>
  20 #include <linux/sockios.h>
  21 #include <linux/init.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/netlink.h>
  24 #include <linux/rtnetlink.h>
  25 #include <linux/proc_fs.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/timer.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/in_route.h>
  30 #include <linux/list.h>
  31 #include <linux/rcupdate.h>
  32 #include <asm/atomic.h>
  33 #include <asm/uaccess.h>
  34 #include <net/neighbour.h>
  35 #include <net/dst.h>
  36 #include <net/flow.h>
  37 #include <net/dn.h>
  38 #include <net/dn_fib.h>
  39 #include <net/dn_neigh.h>
  40 #include <net/dn_dev.h>
  41
  42 struct dn_fib_rule
  43 {
  44         struct hlist_node       r_hlist;
  45         atomic_t                r_clntref;
  46         u32                     r_preference;
  47         unsigned char           r_table;
  48         unsigned char           r_action;
  49         unsigned char           r_dst_len;
  50         unsigned char           r_src_len;
  51         __le16                  r_src;
  52         __le16                  r_srcmask;
  53         __le16                  r_dst;
  54         __le16                  r_dstmask;
  55         __le16                  r_srcmap;
  56         u8                      r_flags;
  57 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  58         u32                     r_fwmark;
  59 #endif
  60         int                     r_ifindex;
  61         char                    r_ifname[IFNAMSIZ];
  62         int                     r_dead;
  63         struct rcu_head         rcu;
  64 };
  65
  66 static struct dn_fib_rule default_rule = {
  67         .r_clntref =            ATOMIC_INIT(2),
  68         .r_preference =         0x7fff,
  69         .r_table =              RT_TABLE_MAIN,
  70         .r_action =             RTN_UNICAST
  71 };
  72
  73 static struct hlist_head dn_fib_rules;
  74
  75 int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
  76 {
  77         struct rtattr **rta = arg;
  78         struct rtmsg *rtm = NLMSG_DATA(nlh);
  79         struct dn_fib_rule *r;
  80         struct hlist_node *node;
  81         int err = -ESRCH;
  82
  83         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
  84                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
  85                         rtm->rtm_src_len == r->r_src_len &&
  86                         rtm->rtm_dst_len == r->r_dst_len &&
  87                         (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
  88 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  89                         (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
  90 #endif
  91                         (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
  92                         (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
  93                         (!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
  94                         (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
  95
  96                         err = -EPERM;
  97                         if (r == &default_rule)
  98                                 break;
  99
 100                         hlist_del_rcu(&r->r_hlist);
 101                         r->r_dead = 1;
 102                         dn_fib_rule_put(r);
 103                         err = 0;
 104                         break;
 105                 }
 106         }
 107
 108         return err;
 109 }
 110
 111 static inline void dn_fib_rule_put_rcu(struct rcu_head *head)
 112 {
 113         struct dn_fib_rule *r = container_of(head, struct dn_fib_rule, rcu);
 114         kfree(r);
 115 }
 116
 117 void dn_fib_rule_put(struct dn_fib_rule *r)
 118 {
 119         if (atomic_dec_and_test(&r->r_clntref)) {
 120                 if (r->r_dead)
 121                         call_rcu(&r->rcu, dn_fib_rule_put_rcu);
 122                 else
 123                         printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
 124         }
 125 }
 126
 127
 128 int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 129 {
 130         struct rtattr **rta = arg;
 131         struct rtmsg *rtm = NLMSG_DATA(nlh);
 132         struct dn_fib_rule *r, *new_r, *last = NULL;
 133         struct hlist_node *node = NULL;
 134         unsigned char table_id;
 135
 136         if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
 137                 return -EINVAL;
 138
 139         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 140                 return -EINVAL;
 141
 142         if (rtm->rtm_type == RTN_NAT)
 143                 return -EINVAL;
 144
 145         table_id = rtm->rtm_table;
 146         if (table_id == RT_TABLE_UNSPEC) {
 147                 struct dn_fib_table *tb;
 148                 if (rtm->rtm_type == RTN_UNICAST) {
 149                         if ((tb = dn_fib_empty_table()) == NULL)
 150                                 return -ENOBUFS;
 151                         table_id = tb->n;
 152                 }
 153         }
 154
 155         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 156         if (!new_r)
 157                 return -ENOMEM;
 158         memset(new_r, 0, sizeof(*new_r));
 159
 160         if (rta[RTA_SRC-1])
 161                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
 162         if (rta[RTA_DST-1])
 163                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
 164         if (rta[RTA_GATEWAY-1])
 165                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 2);
 166         new_r->r_src_len = rtm->rtm_src_len;
 167         new_r->r_dst_len = rtm->rtm_dst_len;
 168         new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
 169         new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
 170 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 171         if (rta[RTA_PROTOINFO-1])
 172                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 173 #endif
 174         new_r->r_action = rtm->rtm_type;
 175         new_r->r_flags = rtm->rtm_flags;
 176         if (rta[RTA_PRIORITY-1])
 177                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 178         new_r->r_table = table_id;
 179         if (rta[RTA_IIF-1]) {
 180                 struct net_device *dev;
 181                 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
 182                 new_r->r_ifindex = -1;
 183                 dev = dev_get_by_name(new_r->r_ifname);
 184                 if (dev) {
 185                         new_r->r_ifindex = dev->ifindex;
 186                         dev_put(dev);
 187                 }
 188         }
 189
 190         r = container_of(dn_fib_rules.first, struct dn_fib_rule, r_hlist);
 191         if (!new_r->r_preference) {
 192                 if (r && r->r_hlist.next != NULL) {
 193                         r = container_of(r->r_hlist.next, struct dn_fib_rule, r_hlist);
 194                         if (r->r_preference)
 195                                 new_r->r_preference = r->r_preference - 1;
 196                 }
 197         }
 198
 199         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
 200                 if (r->r_preference > new_r->r_preference)
 201                         break;
 202                 last = r;
 203         }
 204         atomic_inc(&new_r->r_clntref);
 205
 206         if (last)
 207                 hlist_add_after_rcu(&last->r_hlist, &new_r->r_hlist);
 208         else
 209                 hlist_add_before_rcu(&new_r->r_hlist, &r->r_hlist);
 210         return 0;
 211 }
 212
 213
 214 int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
 215 {
 216         struct dn_fib_rule *r, *policy;
 217         struct dn_fib_table *tb;
 218         __le16 saddr = flp->fld_src;
 219         __le16 daddr = flp->fld_dst;
 220         struct hlist_node *node;
 221         int err;
 222
 223         rcu_read_lock();
 224
 225         hlist_for_each_entry_rcu(r, node, &dn_fib_rules, r_hlist) {
 226                 if (((saddr^r->r_src) & r->r_srcmask) ||
 227                     ((daddr^r->r_dst) & r->r_dstmask) ||
 228 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 229                     (r->r_fwmark && r->r_fwmark != flp->fld_fwmark) ||
 230 #endif
 231                     (r->r_ifindex && r->r_ifindex != flp->iif))
 232                         continue;
 233
 234                 switch(r->r_action) {
 235                         case RTN_UNICAST:
 236                         case RTN_NAT:
 237                                 policy = r;
 238                                 break;
 239                         case RTN_UNREACHABLE:
 240                                 rcu_read_unlock();
 241                                 return -ENETUNREACH;
 242                         default:
 243                         case RTN_BLACKHOLE:
 244                                 rcu_read_unlock();
 245                                 return -EINVAL;
 246                         case RTN_PROHIBIT:
 247                                 rcu_read_unlock();
 248                                 return -EACCES;
 249                 }
 250
 251                 if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
 252                         continue;
 253                 err = tb->lookup(tb, flp, res);
 254                 if (err == 0) {
 255                         res->r = policy;
 256                         if (policy)
 257                                 atomic_inc(&policy->r_clntref);
 258                         rcu_read_unlock();
 259                         return 0;
 260                 }
 261                 if (err < 0 && err != -EAGAIN) {
 262                         rcu_read_unlock();
 263                         return err;
 264                 }
 265         }
 266
 267         rcu_read_unlock();
 268         return -ESRCH;
 269 }
 270
 271 unsigned dnet_addr_type(__le16 addr)
 272 {
 273         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 274         struct dn_fib_res res;
 275         unsigned ret = RTN_UNICAST;
 276         struct dn_fib_table *tb = dn_fib_tables[RT_TABLE_LOCAL];
 277
 278         res.r = NULL;
 279
 280         if (tb) {
 281                 if (!tb->lookup(tb, &fl, &res)) {
 282                         ret = res.type;
 283                         dn_fib_res_put(&res);
 284                 }
 285         }
 286         return ret;
 287 }
 288
 289 __le16 dn_fib_rules_policy(__le16 saddr, struct dn_fib_res *res, unsigned *flags)
 290 {
 291         struct dn_fib_rule *r = res->r;
 292
 293         if (r->r_action == RTN_NAT) {
 294                 int addrtype = dnet_addr_type(r->r_srcmap);
 295
 296                 if (addrtype == RTN_NAT) {
 297                         saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
 298                         *flags |= RTCF_SNAT;
 299                 } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
 300                         saddr = r->r_srcmap;
 301                         *flags |= RTCF_MASQ;
 302                 }
 303         }
 304         return saddr;
 305 }
 306
 307 static void dn_fib_rules_detach(struct net_device *dev)
 308 {
 309         struct hlist_node *node;
 310         struct dn_fib_rule *r;
 311
 312         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
 313                 if (r->r_ifindex == dev->ifindex)
 314                         r->r_ifindex = -1;
 315         }
 316 }
 317
 318 static void dn_fib_rules_attach(struct net_device *dev)
 319 {
 320         struct hlist_node *node;
 321         struct dn_fib_rule *r;
 322
 323         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
 324                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
 325                         r->r_ifindex = dev->ifindex;
 326         }
 327 }
 328
 329 static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 330 {
 331         struct net_device *dev = ptr;
 332
 333         switch(event) {
 334                 case NETDEV_UNREGISTER:
 335                         dn_fib_rules_detach(dev);
 336                         dn_fib_sync_down(0, dev, 1);
 337                 case NETDEV_REGISTER:
 338                         dn_fib_rules_attach(dev);
 339                         dn_fib_sync_up(dev);
 340         }
 341
 342         return NOTIFY_DONE;
 343 }
 344
 345
 346 static struct notifier_block dn_fib_rules_notifier = {
 347         .notifier_call =        dn_fib_rules_event,
 348 };
 349
 350 static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r,
 351                             struct netlink_callback *cb, unsigned int flags)
 352 {
 353         struct rtmsg *rtm;
 354         struct nlmsghdr *nlh;
 355         unsigned char *b = skb->tail;
 356
 357
 358         nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
 359         rtm = NLMSG_DATA(nlh);
 360         rtm->rtm_family = AF_DECnet;
 361         rtm->rtm_dst_len = r->r_dst_len;
 362         rtm->rtm_src_len = r->r_src_len;
 363         rtm->rtm_tos = 0;
 364 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 365         if (r->r_fwmark)
 366                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 367 #endif
 368         rtm->rtm_table = r->r_table;
 369         rtm->rtm_protocol = 0;
 370         rtm->rtm_scope = 0;
 371         rtm->rtm_type = r->r_action;
 372         rtm->rtm_flags = r->r_flags;
 373
 374         if (r->r_dst_len)
 375                 RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
 376         if (r->r_src_len)
 377                 RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
 378         if (r->r_ifname[0])
 379                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 380         if (r->r_preference)
 381                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 382         if (r->r_srcmap)
 383                 RTA_PUT(skb, RTA_GATEWAY, 2, &r->r_srcmap);
 384         nlh->nlmsg_len = skb->tail - b;
 385         return skb->len;
 386
 387 nlmsg_failure:
 388 rtattr_failure:
 389         skb_trim(skb, b - skb->data);
 390         return -1;
 391 }
 392
 393 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 394 {
 395         int idx = 0;
 396         int s_idx = cb->args[0];
 397         struct dn_fib_rule *r;
 398         struct hlist_node *node;
 399
 400         rcu_read_lock();
 401         hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
 402                 if (idx < s_idx)
 403                         goto next;
 404                 if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
 405                         break;
 406 next:
 407                 idx++;
 408         }
 409         rcu_read_unlock();
 410         cb->args[0] = idx;
 411
 412         return skb->len;
 413 }
 414
 415 void __init dn_fib_rules_init(void)
 416 {
 417         INIT_HLIST_HEAD(&dn_fib_rules);
 418         hlist_add_head(&default_rule.r_hlist, &dn_fib_rules);
 419         register_netdevice_notifier(&dn_fib_rules_notifier);
 420 }
 421
 422 void __exit dn_fib_rules_cleanup(void)
 423 {
 424         unregister_netdevice_notifier(&dn_fib_rules_notifier);
 425 }
 426
 427