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 static struct dn_fib_rule default_rule = {
  52         .common = {
  53                 .refcnt =               ATOMIC_INIT(2),
  54                 .pref =                 0x7fff,
  55                 .table =                RT_TABLE_MAIN,
  56                 .action =               FR_ACT_TO_TBL,
  57         },
  58 };
  59
  60 static LIST_HEAD(dn_fib_rules);
  61
  62
  63 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
  64 {
  65         struct fib_lookup_arg arg = {
  66                 .result = res,
  67         };
  68         int err;
  69
  70         err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
  71         res->r = arg.rule;
  72
  73         return err;
  74 }
  75
  76 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  77                               int flags, struct fib_lookup_arg *arg)
  78 {
  79         int err = -EAGAIN;
  80         struct dn_fib_table *tbl;
  81
  82         switch(rule->action) {
  83         case FR_ACT_TO_TBL:
  84                 break;
  85
  86         case FR_ACT_UNREACHABLE:
  87                 err = -ENETUNREACH;
  88                 goto errout;
  89
  90         case FR_ACT_PROHIBIT:
  91                 err = -EACCES;
  92                 goto errout;
  93
  94         case FR_ACT_BLACKHOLE:
  95         default:
  96                 err = -EINVAL;
  97                 goto errout;
  98         }
  99
 100         tbl = dn_fib_get_table(rule->table, 0);
 101         if (tbl == NULL)
 102                 goto errout;
 103
 104         err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
 105         if (err > 0)
 106                 err = -EAGAIN;
 107 errout:
 108         return err;
 109 }
 110
 111 static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
 112         FRA_GENERIC_POLICY,
 113 };
 114
 115 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 116 {
 117         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 118         __le16 daddr = fl->fld_dst;
 119         __le16 saddr = fl->fld_src;
 120
 121         if (((saddr ^ r->src) & r->srcmask) ||
 122             ((daddr ^ r->dst) & r->dstmask))
 123                 return 0;
 124
 125         return 1;
 126 }
 127
 128 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 129                                  struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 130                                  struct nlattr **tb)
 131 {
 132         int err = -EINVAL;
 133         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 134
 135         if (frh->tos)
 136                 goto  errout;
 137
 138         if (rule->table == RT_TABLE_UNSPEC) {
 139                 if (rule->action == FR_ACT_TO_TBL) {
 140                         struct dn_fib_table *table;
 141
 142                         table = dn_fib_empty_table();
 143                         if (table == NULL) {
 144                                 err = -ENOBUFS;
 145                                 goto errout;
 146                         }
 147
 148                         rule->table = table->n;
 149                 }
 150         }
 151
 152         if (frh->src_len)
 153                 r->src = nla_get_le16(tb[FRA_SRC]);
 154
 155         if (frh->dst_len)
 156                 r->dst = nla_get_le16(tb[FRA_DST]);
 157
 158         r->src_len = frh->src_len;
 159         r->srcmask = dnet_make_mask(r->src_len);
 160         r->dst_len = frh->dst_len;
 161         r->dstmask = dnet_make_mask(r->dst_len);
 162         err = 0;
 163 errout:
 164         return err;
 165 }
 166
 167 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 168                                struct nlattr **tb)
 169 {
 170         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 171
 172         if (frh->src_len && (r->src_len != frh->src_len))
 173                 return 0;
 174
 175         if (frh->dst_len && (r->dst_len != frh->dst_len))
 176                 return 0;
 177
 178         if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
 179                 return 0;
 180
 181         if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
 182                 return 0;
 183
 184         return 1;
 185 }
 186
 187 unsigned dnet_addr_type(__le16 addr)
 188 {
 189         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 190         struct dn_fib_res res;
 191         unsigned ret = RTN_UNICAST;
 192         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 193
 194         res.r = NULL;
 195
 196         if (tb) {
 197                 if (!tb->lookup(tb, &fl, &res)) {
 198                         ret = res.type;
 199                         dn_fib_res_put(&res);
 200                 }
 201         }
 202         return ret;
 203 }
 204
 205 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 206                             struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 207 {
 208         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 209
 210         frh->family = AF_DECnet;
 211         frh->dst_len = r->dst_len;
 212         frh->src_len = r->src_len;
 213         frh->tos = 0;
 214
 215         if (r->dst_len)
 216                 NLA_PUT_LE16(skb, FRA_DST, r->dst);
 217         if (r->src_len)
 218                 NLA_PUT_LE16(skb, FRA_SRC, r->src);
 219
 220         return 0;
 221
 222 nla_put_failure:
 223         return -ENOBUFS;
 224 }
 225
 226 static u32 dn_fib_rule_default_pref(void)
 227 {
 228         struct list_head *pos;
 229         struct fib_rule *rule;
 230
 231         if (!list_empty(&dn_fib_rules)) {
 232                 pos = dn_fib_rules.next;
 233                 if (pos->next != &dn_fib_rules) {
 234                         rule = list_entry(pos->next, struct fib_rule, list);
 235                         if (rule->pref)
 236                                 return rule->pref - 1;
 237                 }
 238         }
 239
 240         return 0;
 241 }
 242
 243 static void dn_fib_rule_flush_cache(void)
 244 {
 245         dn_rt_cache_flush(-1);
 246 }
 247
 248 static struct fib_rules_ops dn_fib_rules_ops = {
 249         .family         = AF_DECnet,
 250         .rule_size      = sizeof(struct dn_fib_rule),
 251         .addr_size      = sizeof(u16),
 252         .action         = dn_fib_rule_action,
 253         .match          = dn_fib_rule_match,
 254         .configure      = dn_fib_rule_configure,
 255         .compare        = dn_fib_rule_compare,
 256         .fill           = dn_fib_rule_fill,
 257         .default_pref   = dn_fib_rule_default_pref,
 258         .flush_cache    = dn_fib_rule_flush_cache,
 259         .nlgroup        = RTNLGRP_DECnet_RULE,
 260         .policy         = dn_fib_rule_policy,
 261         .rules_list     = &dn_fib_rules,
 262         .owner          = THIS_MODULE,
 263 };
 264
 265 void __init dn_fib_rules_init(void)
 266 {
 267         list_add_tail(&default_rule.common.list, &dn_fib_rules);
 268         fib_rules_register(&dn_fib_rules_ops);
 269 }
 270
 271 void __exit dn_fib_rules_cleanup(void)
 272 {
 273         fib_rules_unregister(&dn_fib_rules_ops);
 274 }
 275
 276