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