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 <asm/atomic.h>
  31 #include <asm/uaccess.h>
  32 #include <net/neighbour.h>
  33 #include <net/dst.h>
  34 #include <net/flow.h>
  35 #include <net/dn.h>
  36 #include <net/dn_fib.h>
  37 #include <net/dn_neigh.h>
  38 #include <net/dn_dev.h>
  39
  40 struct dn_fib_rule
  41 {
  42         struct dn_fib_rule      *r_next;
  43         atomic_t                r_clntref;
  44         u32                     r_preference;
  45         unsigned char           r_table;
  46         unsigned char           r_action;
  47         unsigned char           r_dst_len;
  48         unsigned char           r_src_len;
  49         dn_address              r_src;
  50         dn_address              r_srcmask;
  51         dn_address              r_dst;
  52         dn_address              r_dstmask;
  53         dn_address              r_srcmap;
  54         u8                      r_flags;
  55 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  56         u32                     r_fwmark;
  57 #endif
  58         int                     r_ifindex;
  59         char                    r_ifname[IFNAMSIZ];
  60         int                     r_dead;
  61 };
  62
  63 static struct dn_fib_rule default_rule = {
  64         .r_clntref =            ATOMIC_INIT(2),
  65         .r_preference =         0x7fff,
  66         .r_table =              RT_TABLE_MAIN,
  67         .r_action =             RTN_UNICAST
  68 };
  69
  70 static struct dn_fib_rule *dn_fib_rules = &default_rule;
  71 static DEFINE_RWLOCK(dn_fib_rules_lock);
  72
  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, **rp;
  79         int err = -ESRCH;
  80
  81         for(rp=&dn_fib_rules; (r=*rp) != NULL; rp = &r->r_next) {
  82                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
  83                         rtm->rtm_src_len == r->r_src_len &&
  84                         rtm->rtm_dst_len == r->r_dst_len &&
  85                         (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
  86 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  87                         (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
  88 #endif
  89                         (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
  90                         (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
  91                         (!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
  92                         (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
  93
  94                         err = -EPERM;
  95                         if (r == &default_rule)
  96                                 break;
  97
  98                         write_lock_bh(&dn_fib_rules_lock);
  99                         *rp = r->r_next;
 100                         r->r_dead = 1;
 101                         write_unlock_bh(&dn_fib_rules_lock);
 102                         dn_fib_rule_put(r);
 103                         err = 0;
 104                         break;
 105                 }
 106         }
 107
 108         return err;
 109 }
 110
 111 void dn_fib_rule_put(struct dn_fib_rule *r)
 112 {
 113         if (atomic_dec_and_test(&r->r_clntref)) {
 114                 if (r->r_dead)
 115                         kfree(r);
 116                 else
 117                         printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
 118         }
 119 }
 120
 121
 122 int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 123 {
 124         struct rtattr **rta = arg;
 125         struct rtmsg *rtm = NLMSG_DATA(nlh);
 126         struct dn_fib_rule *r, *new_r, **rp;
 127         unsigned char table_id;
 128
 129         if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
 130                 return -EINVAL;
 131
 132         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 133                 return -EINVAL;
 134
 135         if (rtm->rtm_type == RTN_NAT)
 136                 return -EINVAL;
 137
 138         table_id = rtm->rtm_table;
 139         if (table_id == RT_TABLE_UNSPEC) {
 140                 struct dn_fib_table *tb;
 141                 if (rtm->rtm_type == RTN_UNICAST) {
 142                         if ((tb = dn_fib_empty_table()) == NULL)
 143                                 return -ENOBUFS;
 144                         table_id = tb->n;
 145                 }
 146         }
 147
 148         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 149         if (!new_r)
 150                 return -ENOMEM;
 151         memset(new_r, 0, sizeof(*new_r));
 152         if (rta[RTA_SRC-1])
 153                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
 154         if (rta[RTA_DST-1])
 155                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
 156         if (rta[RTA_GATEWAY-1])
 157                 memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 2);
 158         new_r->r_src_len = rtm->rtm_src_len;
 159         new_r->r_dst_len = rtm->rtm_dst_len;
 160         new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
 161         new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
 162 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 163         if (rta[RTA_PROTOINFO-1])
 164                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 165 #endif
 166         new_r->r_action = rtm->rtm_type;
 167         new_r->r_flags = rtm->rtm_flags;
 168         if (rta[RTA_PRIORITY-1])
 169                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 170         new_r->r_table = table_id;
 171         if (rta[RTA_IIF-1]) {
 172                 struct net_device *dev;
 173                 rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
 174                 new_r->r_ifindex = -1;
 175                 dev = dev_get_by_name(new_r->r_ifname);
 176                 if (dev) {
 177                         new_r->r_ifindex = dev->ifindex;
 178                         dev_put(dev);
 179                 }
 180         }
 181
 182         rp = &dn_fib_rules;
 183         if (!new_r->r_preference) {
 184                 r = dn_fib_rules;
 185                 if (r && (r = r->r_next) != NULL) {
 186                         rp = &dn_fib_rules->r_next;
 187                         if (r->r_preference)
 188                                 new_r->r_preference = r->r_preference - 1;
 189                 }
 190         }
 191
 192         while((r=*rp) != NULL) {
 193                 if (r->r_preference > new_r->r_preference)
 194                         break;
 195                 rp = &r->r_next;
 196         }
 197
 198         new_r->r_next = r;
 199         atomic_inc(&new_r->r_clntref);
 200         write_lock_bh(&dn_fib_rules_lock);
 201         *rp = new_r;
 202         write_unlock_bh(&dn_fib_rules_lock);
 203         return 0;
 204 }
 205
 206
 207 int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
 208 {
 209         struct dn_fib_rule *r, *policy;
 210         struct dn_fib_table *tb;
 211         dn_address saddr = flp->fld_src;
 212         dn_address daddr = flp->fld_dst;
 213         int err;
 214
 215         read_lock(&dn_fib_rules_lock);
 216         for(r = dn_fib_rules; r; r = r->r_next) {
 217                 if (((saddr^r->r_src) & r->r_srcmask) ||
 218                     ((daddr^r->r_dst) & r->r_dstmask) ||
 219 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 220                     (r->r_fwmark && r->r_fwmark != flp->fld_fwmark) ||
 221 #endif
 222                     (r->r_ifindex && r->r_ifindex != flp->iif))
 223                         continue;
 224
 225                 switch(r->r_action) {
 226                         case RTN_UNICAST:
 227                         case RTN_NAT:
 228                                 policy = r;
 229                                 break;
 230                         case RTN_UNREACHABLE:
 231                                 read_unlock(&dn_fib_rules_lock);
 232                                 return -ENETUNREACH;
 233                         default:
 234                         case RTN_BLACKHOLE:
 235                                 read_unlock(&dn_fib_rules_lock);
 236                                 return -EINVAL;
 237                         case RTN_PROHIBIT:
 238                                 read_unlock(&dn_fib_rules_lock);
 239                                 return -EACCES;
 240                 }
 241
 242                 if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
 243                         continue;
 244                 err = tb->lookup(tb, flp, res);
 245                 if (err == 0) {
 246                         res->r = policy;
 247                         if (policy)
 248                                 atomic_inc(&policy->r_clntref);
 249                         read_unlock(&dn_fib_rules_lock);
 250                         return 0;
 251                 }
 252                 if (err < 0 && err != -EAGAIN) {
 253                         read_unlock(&dn_fib_rules_lock);
 254                         return err;
 255                 }
 256         }
 257
 258         read_unlock(&dn_fib_rules_lock);
 259         return -ESRCH;
 260 }
 261
 262 unsigned dnet_addr_type(__u16 addr)
 263 {
 264         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 265         struct dn_fib_res res;
 266         unsigned ret = RTN_UNICAST;
 267         struct dn_fib_table *tb = dn_fib_tables[RT_TABLE_LOCAL];
 268
 269         res.r = NULL;
 270
 271         if (tb) {
 272                 if (!tb->lookup(tb, &fl, &res)) {
 273                         ret = res.type;
 274                         dn_fib_res_put(&res);
 275                 }
 276         }
 277         return ret;
 278 }
 279
 280 __u16 dn_fib_rules_policy(__u16 saddr, struct dn_fib_res *res, unsigned *flags)
 281 {
 282         struct dn_fib_rule *r = res->r;
 283
 284         if (r->r_action == RTN_NAT) {
 285                 int addrtype = dnet_addr_type(r->r_srcmap);
 286
 287                 if (addrtype == RTN_NAT) {
 288                         saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
 289                         *flags |= RTCF_SNAT;
 290                 } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
 291                         saddr = r->r_srcmap;
 292                         *flags |= RTCF_MASQ;
 293                 }
 294         }
 295         return saddr;
 296 }
 297
 298 static void dn_fib_rules_detach(struct net_device *dev)
 299 {
 300         struct dn_fib_rule *r;
 301
 302         for(r = dn_fib_rules; r; r = r->r_next) {
 303                 if (r->r_ifindex == dev->ifindex) {
 304                         write_lock_bh(&dn_fib_rules_lock);
 305                         r->r_ifindex = -1;
 306                         write_unlock_bh(&dn_fib_rules_lock);
 307                 }
 308         }
 309 }
 310
 311 static void dn_fib_rules_attach(struct net_device *dev)
 312 {
 313         struct dn_fib_rule *r;
 314
 315         for(r = dn_fib_rules; r; r = r->r_next) {
 316                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
 317                         write_lock_bh(&dn_fib_rules_lock);
 318                         r->r_ifindex = dev->ifindex;
 319                         write_unlock_bh(&dn_fib_rules_lock);
 320                 }
 321         }
 322 }
 323
 324 static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 325 {
 326         struct net_device *dev = ptr;
 327
 328         switch(event) {
 329                 case NETDEV_UNREGISTER:
 330                         dn_fib_rules_detach(dev);
 331                         dn_fib_sync_down(0, dev, 1);
 332                 case NETDEV_REGISTER:
 333                         dn_fib_rules_attach(dev);
 334                         dn_fib_sync_up(dev);
 335         }
 336
 337         return NOTIFY_DONE;
 338 }
 339
 340
 341 static struct notifier_block dn_fib_rules_notifier = {
 342         .notifier_call =        dn_fib_rules_event,
 343 };
 344
 345 static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r,
 346                             struct netlink_callback *cb, unsigned int flags)
 347 {
 348         struct rtmsg *rtm;
 349         struct nlmsghdr *nlh;
 350         unsigned char *b = skb->tail;
 351
 352
 353         nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
 354         rtm = NLMSG_DATA(nlh);
 355         rtm->rtm_family = AF_DECnet;
 356         rtm->rtm_dst_len = r->r_dst_len;
 357         rtm->rtm_src_len = r->r_src_len;
 358         rtm->rtm_tos = 0;
 359 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 360         if (r->r_fwmark)
 361                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 362 #endif
 363         rtm->rtm_table = r->r_table;
 364         rtm->rtm_protocol = 0;
 365         rtm->rtm_scope = 0;
 366         rtm->rtm_type = r->r_action;
 367         rtm->rtm_flags = r->r_flags;
 368
 369         if (r->r_dst_len)
 370                 RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
 371         if (r->r_src_len)
 372                 RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
 373         if (r->r_ifname[0])
 374                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 375         if (r->r_preference)
 376                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 377         if (r->r_srcmap)
 378                 RTA_PUT(skb, RTA_GATEWAY, 2, &r->r_srcmap);
 379         nlh->nlmsg_len = skb->tail - b;
 380         return skb->len;
 381
 382 nlmsg_failure:
 383 rtattr_failure:
 384         skb_trim(skb, b - skb->data);
 385         return -1;
 386 }
 387
 388 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 389 {
 390         int idx;
 391         int s_idx = cb->args[0];
 392         struct dn_fib_rule *r;
 393
 394         read_lock(&dn_fib_rules_lock);
 395         for(r = dn_fib_rules, idx = 0; r; r = r->r_next, idx++) {
 396                 if (idx < s_idx)
 397                         continue;
 398                 if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
 399                         break;
 400         }
 401         read_unlock(&dn_fib_rules_lock);
 402         cb->args[0] = idx;
 403
 404         return skb->len;
 405 }
 406
 407 void __init dn_fib_rules_init(void)
 408 {
 409         register_netdevice_notifier(&dn_fib_rules_notifier);
 410 }
 411
 412 void __exit dn_fib_rules_cleanup(void)
 413 {
 414         unregister_netdevice_notifier(&dn_fib_rules_notifier);
 415 }
 416
 417