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  *              Steve Whitehouse <steve@chygwyn.com>
  15  *              Updated for Thomas Graf's generic rules
  16  *
  17  */
  18 #include <linux/net.h>
  19 #include <linux/init.h>
  20 #include <linux/netlink.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/list.h>
  25 #include <linux/rcupdate.h>
  26 #include <net/neighbour.h>
  27 #include <net/dst.h>
  28 #include <net/flow.h>
  29 #include <net/fib_rules.h>
  30 #include <net/dn.h>
  31 #include <net/dn_fib.h>
  32 #include <net/dn_neigh.h>
  33 #include <net/dn_dev.h>
  34 #include <net/dn_route.h>
  35
  36 static struct fib_rules_ops dn_fib_rules_ops;
  37
  38 struct dn_fib_rule
  39 {
  40         struct fib_rule         common;
  41         unsigned char           dst_len;
  42         unsigned char           src_len;
  43         __le16                  src;
  44         __le16                  srcmask;
  45         __le16                  dst;
  46         __le16                  dstmask;
  47         __le16                  srcmap;
  48         u8                      flags;
  49 };
  50
  51
  52 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
  53 {
  54         struct fib_lookup_arg arg = {
  55                 .result = res,
  56         };
  57         int err;
  58
  59         err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
  60         res->r = arg.rule;
  61
  62         return err;
  63 }
  64
  65 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  66                               int flags, struct fib_lookup_arg *arg)
  67 {
  68         int err = -EAGAIN;
  69         struct dn_fib_table *tbl;
  70
  71         switch(rule->action) {
  72         case FR_ACT_TO_TBL:
  73                 break;
  74
  75         case FR_ACT_UNREACHABLE:
  76                 err = -ENETUNREACH;
  77                 goto errout;
  78
  79         case FR_ACT_PROHIBIT:
  80                 err = -EACCES;
  81                 goto errout;
  82
  83         case FR_ACT_BLACKHOLE:
  84         default:
  85                 err = -EINVAL;
  86                 goto errout;
  87         }
  88
  89         tbl = dn_fib_get_table(rule->table, 0);
  90         if (tbl == NULL)
  91                 goto errout;
  92
  93         err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
  94         if (err > 0)
  95                 err = -EAGAIN;
  96 errout:
  97         return err;
  98 }
  99
 100 static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
 101         FRA_GENERIC_POLICY,
 102 };
 103
 104 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 105 {
 106         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 107         __le16 daddr = fl->fld_dst;
 108         __le16 saddr = fl->fld_src;
 109
 110         if (((saddr ^ r->src) & r->srcmask) ||
 111             ((daddr ^ r->dst) & r->dstmask))
 112                 return 0;
 113
 114         return 1;
 115 }
 116
 117 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 118                                  struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 119                                  struct nlattr **tb)
 120 {
 121         int err = -EINVAL;
 122         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 123
 124         if (frh->tos)
 125                 goto  errout;
 126
 127         if (rule->table == RT_TABLE_UNSPEC) {
 128                 if (rule->action == FR_ACT_TO_TBL) {
 129                         struct dn_fib_table *table;
 130
 131                         table = dn_fib_empty_table();
 132                         if (table == NULL) {
 133                                 err = -ENOBUFS;
 134                                 goto errout;
 135                         }
 136
 137                         rule->table = table->n;
 138                 }
 139         }
 140
 141         if (frh->src_len)
 142                 r->src = nla_get_le16(tb[FRA_SRC]);
 143
 144         if (frh->dst_len)
 145                 r->dst = nla_get_le16(tb[FRA_DST]);
 146
 147         r->src_len = frh->src_len;
 148         r->srcmask = dnet_make_mask(r->src_len);
 149         r->dst_len = frh->dst_len;
 150         r->dstmask = dnet_make_mask(r->dst_len);
 151         err = 0;
 152 errout:
 153         return err;
 154 }
 155
 156 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 157                                struct nlattr **tb)
 158 {
 159         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 160
 161         if (frh->src_len && (r->src_len != frh->src_len))
 162                 return 0;
 163
 164         if (frh->dst_len && (r->dst_len != frh->dst_len))
 165                 return 0;
 166
 167         if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
 168                 return 0;
 169
 170         if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
 171                 return 0;
 172
 173         return 1;
 174 }
 175
 176 unsigned dnet_addr_type(__le16 addr)
 177 {
 178         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 179         struct dn_fib_res res;
 180         unsigned ret = RTN_UNICAST;
 181         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 182
 183         res.r = NULL;
 184
 185         if (tb) {
 186                 if (!tb->lookup(tb, &fl, &res)) {
 187                         ret = res.type;
 188                         dn_fib_res_put(&res);
 189                 }
 190         }
 191         return ret;
 192 }
 193
 194 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 195                             struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 196 {
 197         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 198
 199         frh->family = AF_DECnet;
 200         frh->dst_len = r->dst_len;
 201         frh->src_len = r->src_len;
 202         frh->tos = 0;
 203
 204         if (r->dst_len)
 205                 NLA_PUT_LE16(skb, FRA_DST, r->dst);
 206         if (r->src_len)
 207                 NLA_PUT_LE16(skb, FRA_SRC, r->src);
 208
 209         return 0;
 210
 211 nla_put_failure:
 212         return -ENOBUFS;
 213 }
 214
 215 static u32 dn_fib_rule_default_pref(struct fib_rules_ops *ops)
 216 {
 217         struct list_head *pos;
 218         struct fib_rule *rule;
 219
 220         if (!list_empty(&dn_fib_rules_ops.rules_list)) {
 221                 pos = dn_fib_rules_ops.rules_list.next;
 222                 if (pos->next != &dn_fib_rules_ops.rules_list) {
 223                         rule = list_entry(pos->next, struct fib_rule, list);
 224                         if (rule->pref)
 225                                 return rule->pref - 1;
 226                 }
 227         }
 228
 229         return 0;
 230 }
 231
 232 static void dn_fib_rule_flush_cache(struct fib_rules_ops *ops)
 233 {
 234         dn_rt_cache_flush(-1);
 235 }
 236
 237 static struct fib_rules_ops dn_fib_rules_ops = {
 238         .family         = AF_DECnet,
 239         .rule_size      = sizeof(struct dn_fib_rule),
 240         .addr_size      = sizeof(u16),
 241         .action         = dn_fib_rule_action,
 242         .match          = dn_fib_rule_match,
 243         .configure      = dn_fib_rule_configure,
 244         .compare        = dn_fib_rule_compare,
 245         .fill           = dn_fib_rule_fill,
 246         .default_pref   = dn_fib_rule_default_pref,
 247         .flush_cache    = dn_fib_rule_flush_cache,
 248         .nlgroup        = RTNLGRP_DECnet_RULE,
 249         .policy         = dn_fib_rule_policy,
 250         .rules_list     = LIST_HEAD_INIT(dn_fib_rules_ops.rules_list),
 251         .owner          = THIS_MODULE,
 252         .fro_net        = &init_net,
 253 };
 254
 255 void __init dn_fib_rules_init(void)
 256 {
 257         BUG_ON(fib_default_rule_add(&dn_fib_rules_ops, 0x7fff,
 258                                     RT_TABLE_MAIN, 0));
 259         fib_rules_register(&dn_fib_rules_ops);
 260 }
 261
 262 void __exit dn_fib_rules_cleanup(void)
 263 {
 264         fib_rules_unregister(&dn_fib_rules_ops);
 265 }
 266
 267