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 <asm/atomic.h>
  30 #include <asm/uaccess.h>
  31 #include <net/neighbour.h>
  32 #include <net/dst.h>
  33 #include <net/dn.h>
  34 #include <net/dn_fib.h>
  35 #include <net/dn_neigh.h>
  36 #include <net/dn_dev.h>
  37
  38 struct dn_fib_rule
  39 {
  40         struct dn_fib_rule      *r_next;
  41         atomic_t                r_clntref;
  42         u32                     r_preference;
  43         unsigned char           r_table;
  44         unsigned char           r_action;
  45         unsigned char           r_dst_len;
  46         unsigned char           r_src_len;
  47         dn_address              r_src;
  48         dn_address              r_srcmask;
  49         dn_address              r_dst;
  50         dn_address              r_dstmask;
  51         u8                      r_flags;
  52 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  53         u32                     r_fwmark;
  54 #endif
  55         int                     r_ifindex;
  56         char                    r_ifname[IFNAMSIZ];
  57         int                     r_dead;
  58 };
  59
  60 static struct dn_fib_rule default_rule = {
  61         r_clntref:              ATOMIC_INIT(2),
  62         r_preference:           0x7fff,
  63         r_table:                DN_DEFAULT_TABLE,
  64         r_action:               RTN_UNICAST
  65 };
  66
  67 static struct dn_fib_rule *dn_fib_rules = &default_rule;
  68 static rwlock_t dn_fib_rules_lock = RW_LOCK_UNLOCKED;
  69
  70
  71 int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
  72 {
  73         struct rtattr **rta = arg;
  74         struct rtmsg *rtm = NLMSG_DATA(nlh);
  75         struct dn_fib_rule *r, **rp;
  76         int err = -ESRCH;
  77
  78         for(rp=&dn_fib_rules; (r=*rp) != NULL; rp = &r->r_next) {
  79                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
  80                         rtm->rtm_src_len == r->r_src_len &&
  81                         rtm->rtm_dst_len == r->r_dst_len &&
  82                         (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
  83 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  84                         (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
  85 #endif
  86                         (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
  87                         (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
  88                         (!rta[RTA_IIF-1] || strcmp(RTA_DATA(rta[RTA_IIF-1]), r->r_ifname) == 0) &&
  89                         (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
  90
  91                         err = -EPERM;
  92                         if (r == &default_rule)
  93                                 break;
  94
  95                         write_lock_bh(&dn_fib_rules_lock);
  96                         *rp = r->r_next;
  97                         r->r_dead = 1;
  98                         write_unlock_bh(&dn_fib_rules_lock);
  99                         dn_fib_rule_put(r);
 100                         err = 0;
 101                         break;
 102                 }
 103         }
 104
 105         return err;
 106 }
 107
 108 void dn_fib_rule_put(struct dn_fib_rule *r)
 109 {
 110         if (atomic_dec_and_test(&r->r_clntref)) {
 111                 if (r->r_dead)
 112                         kfree(r);
 113                 else
 114                         printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
 115         }
 116 }
 117
 118
 119 int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 120 {
 121         struct rtattr **rta = arg;
 122         struct rtmsg *rtm = NLMSG_DATA(nlh);
 123         struct dn_fib_rule *r, *new_r, **rp;
 124         unsigned char table_id;
 125
 126         if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
 127                 return -EINVAL;
 128
 129         if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
 130                 return -EINVAL;
 131
 132         if (rtm->rtm_type == RTN_NAT)
 133                 return -EINVAL;
 134
 135         table_id = rtm->rtm_table;
 136         if (table_id == RT_TABLE_UNSPEC) {
 137                 struct dn_fib_table *tb;
 138                 if (rtm->rtm_type == RTN_UNICAST) {
 139                         if ((tb = dn_fib_empty_table()) == NULL)
 140                                 return -ENOBUFS;
 141                         table_id = tb->n;
 142                 }
 143         }
 144
 145         new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
 146         if (!new_r)
 147                 return -ENOMEM;
 148         memset(new_r, 0, sizeof(*new_r));
 149         if (rta[RTA_SRC-1])
 150                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
 151         if (rta[RTA_DST-1])
 152                 memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
 153         new_r->r_src_len = rtm->rtm_src_len;
 154         new_r->r_dst_len = rtm->rtm_dst_len;
 155         new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
 156         new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
 157 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 158         if (rta[RTA_PROTOINFO-1])
 159                 memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
 160 #endif
 161         new_r->r_action = rtm->rtm_type;
 162         new_r->r_flags = rtm->rtm_flags;
 163         if (rta[RTA_PRIORITY-1])
 164                 memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
 165         new_r->r_table = table_id;
 166         if (rta[RTA_IIF-1]) {
 167                 struct net_device *dev;
 168                 memcpy(new_r->r_ifname, RTA_DATA(rta[RTA_IIF-1]), IFNAMSIZ);
 169                 new_r->r_ifname[IFNAMSIZ-1] = 0;
 170                 new_r->r_ifindex = -1;
 171                 dev = __dev_get_by_name(new_r->r_ifname);
 172                 if (dev)
 173                         new_r->r_ifindex = dev->ifindex;
 174         }
 175
 176         rp = &dn_fib_rules;
 177         if (!new_r->r_preference) {
 178                 r = dn_fib_rules;
 179                 if (r && (r = r->r_next) != NULL) {
 180                         rp = &dn_fib_rules->r_next;
 181                         if (r->r_preference)
 182                                 new_r->r_preference = r->r_preference - 1;
 183                 }
 184         }
 185
 186         while((r=*rp) != NULL) {
 187                 if (r->r_preference > new_r->r_preference)
 188                         break;
 189                 rp = &r->r_next;
 190         }
 191
 192         new_r->r_next = r;
 193         atomic_inc(&new_r->r_clntref);
 194         write_lock_bh(&dn_fib_rules_lock);
 195         *rp = new_r;
 196         write_unlock_bh(&dn_fib_rules_lock);
 197         return 0;
 198 }
 199
 200
 201 int dn_fib_lookup(struct dn_fib_key *key, struct dn_fib_res *res)
 202 {
 203         struct dn_fib_rule *r, *policy;
 204         struct dn_fib_table *tb;
 205         dn_address saddr = key->src;
 206         dn_address daddr = key->dst;
 207         int err;
 208
 209         read_lock(&dn_fib_rules_lock);
 210         for(r = dn_fib_rules; r; r = r->r_next) {
 211                 if (((saddr^r->r_src) & r->r_srcmask) ||
 212                     ((daddr^r->r_dst) & r->r_dstmask) ||
 213 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 214                     (r->r_fwmark && r->r_fwmark != key->fwmark) ||
 215 #endif
 216                     (r->r_ifindex && r->r_ifindex != key->iif))
 217                         continue;
 218
 219                 switch(r->r_action) {
 220                         case RTN_UNICAST:
 221                                 policy = r;
 222                                 break;
 223                         case RTN_UNREACHABLE:
 224                                 read_unlock(&dn_fib_rules_lock);
 225                                 return -ENETUNREACH;
 226                         default:
 227                         case RTN_BLACKHOLE:
 228                                 read_unlock(&dn_fib_rules_lock);
 229                                 return -EINVAL;
 230                         case RTN_PROHIBIT:
 231                                 read_unlock(&dn_fib_rules_lock);
 232                                 return -EACCES;
 233                 }
 234
 235                 if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
 236                         continue;
 237                 err = tb->lookup(tb, key, res);
 238                 if (err == 0) {
 239                         res->r = policy;
 240                         if (policy)
 241                                 atomic_inc(&policy->r_clntref);
 242                         read_unlock(&dn_fib_rules_lock);
 243                         return 0;
 244                 }
 245                 if (err < 0 && err != -EAGAIN) {
 246                         read_unlock(&dn_fib_rules_lock);
 247                         return err;
 248                 }
 249         }
 250
 251         read_unlock(&dn_fib_rules_lock);
 252         return -ESRCH;
 253 }
 254
 255 static void dn_fib_rules_detach(struct net_device *dev)
 256 {
 257         struct dn_fib_rule *r;
 258
 259         for(r = dn_fib_rules; r; r = r->r_next) {
 260                 if (r->r_ifindex == dev->ifindex) {
 261                         write_lock_bh(&dn_fib_rules_lock);
 262                         r->r_ifindex = -1;
 263                         write_unlock_bh(&dn_fib_rules_lock);
 264                 }
 265         }
 266 }
 267
 268 static void dn_fib_rules_attach(struct net_device *dev)
 269 {
 270         struct dn_fib_rule *r;
 271
 272         for(r = dn_fib_rules; r; r = r->r_next) {
 273                 if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
 274                         write_lock_bh(&dn_fib_rules_lock);
 275                         r->r_ifindex = dev->ifindex;
 276                         write_unlock_bh(&dn_fib_rules_lock);
 277                 }
 278         }
 279 }
 280
 281 static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
 282 {
 283         struct net_device *dev = ptr;
 284
 285         switch(event) {
 286                 case NETDEV_UNREGISTER:
 287                         dn_fib_rules_detach(dev);
 288                         dn_fib_sync_down(0, dev, 1);
 289                 case NETDEV_REGISTER:
 290                         dn_fib_rules_attach(dev);
 291                         dn_fib_sync_up(dev);
 292         }
 293
 294         return NOTIFY_DONE;
 295 }
 296
 297
 298 static struct notifier_block dn_fib_rules_notifier = {
 299         notifier_call:          dn_fib_rules_event,
 300 };
 301
 302 static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r, struct netlink_callback *cb)
 303 {
 304         struct rtmsg *rtm;
 305         struct nlmsghdr *nlh;
 306         unsigned char *b = skb->tail;
 307
 308
 309         nlh = NLMSG_PUT(skb, NETLINK_CREDS(cb->skb)->pid, cb->nlh->nlmsg_seq, RTM_NEWRULE, sizeof(*rtm));
 310         rtm = NLMSG_DATA(nlh);
 311         rtm->rtm_family = AF_DECnet;
 312         rtm->rtm_dst_len = r->r_dst_len;
 313         rtm->rtm_src_len = r->r_src_len;
 314         rtm->rtm_tos = 0;
 315 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 316         if (r->r_fwmark)
 317                 RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
 318 #endif
 319         rtm->rtm_table = r->r_table;
 320         rtm->rtm_protocol = 0;
 321         rtm->rtm_scope = 0;
 322         rtm->rtm_type = r->r_action;
 323         rtm->rtm_flags = r->r_flags;
 324
 325         if (r->r_dst_len)
 326                 RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
 327         if (r->r_src_len)
 328                 RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
 329         if (r->r_ifname[0])
 330                 RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
 331         if (r->r_preference)
 332                 RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
 333         nlh->nlmsg_len = skb->tail - b;
 334         return skb->len;
 335
 336 nlmsg_failure:
 337 rtattr_failure:
 338         skb_put(skb, b - skb->tail);
 339         return -1;
 340 }
 341
 342 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 343 {
 344         int idx;
 345         int s_idx = cb->args[0];
 346         struct dn_fib_rule *r;
 347
 348         read_lock(&dn_fib_rules_lock);
 349         for(r = dn_fib_rules, idx = 0; r; r = r->r_next, idx++) {
 350                 if (idx < s_idx)
 351                         continue;
 352                 if (dn_fib_fill_rule(skb, r, cb) < 0)
 353                         break;
 354         }
 355         read_unlock(&dn_fib_rules_lock);
 356         cb->args[0] = idx;
 357
 358         return skb->len;
 359 }
 360
 361 void __init dn_fib_rules_init(void)
 362 {
 363         register_netdevice_notifier(&dn_fib_rules_notifier);
 364 }
 365
 366 void __exit dn_fib_rules_cleanup(void)
 367 {
 368         unregister_netdevice_notifier(&dn_fib_rules_notifier);
 369 }
 370
 371