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