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