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 <linux/export.h>
  27 #include <net/neighbour.h>
  28 #include <net/dst.h>
  29 #include <net/flow.h>
  30 #include <net/fib_rules.h>
  31 #include <net/dn.h>
  32 #include <net/dn_fib.h>
  33 #include <net/dn_neigh.h>
  34 #include <net/dn_dev.h>
  35 #include <net/dn_route.h>
  36
  37 static struct fib_rules_ops *dn_fib_rules_ops;
  38
  39 struct dn_fib_rule
  40 {
  41         struct fib_rule         common;
  42         unsigned char           dst_len;
  43         unsigned char           src_len;
  44         __le16                  src;
  45         __le16                  srcmask;
  46         __le16                  dst;
  47         __le16                  dstmask;
  48         __le16                  srcmap;
  49         u8                      flags;
  50 };
  51
  52
  53 int dn_fib_lookup(struct flowidn *flp, struct dn_fib_res *res)
  54 {
  55         struct fib_lookup_arg arg = {
  56                 .result = res,
  57         };
  58         int err;
  59
  60         err = fib_rules_lookup(dn_fib_rules_ops,
  61                                flowidn_to_flowi(flp), 0, &arg);
  62         res->r = arg.rule;
  63
  64         return err;
  65 }
  66
  67 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  68                               int flags, struct fib_lookup_arg *arg)
  69 {
  70         struct flowidn *fld = &flp->u.dn;
  71         int err = -EAGAIN;
  72         struct dn_fib_table *tbl;
  73
  74         switch(rule->action) {
  75         case FR_ACT_TO_TBL:
  76                 break;
  77
  78         case FR_ACT_UNREACHABLE:
  79                 err = -ENETUNREACH;
  80                 goto errout;
  81
  82         case FR_ACT_PROHIBIT:
  83                 err = -EACCES;
  84                 goto errout;
  85
  86         case FR_ACT_BLACKHOLE:
  87         default:
  88                 err = -EINVAL;
  89                 goto errout;
  90         }
  91
  92         tbl = dn_fib_get_table(rule->table, 0);
  93         if (tbl == NULL)
  94                 goto errout;
  95
  96         err = tbl->lookup(tbl, fld, (struct dn_fib_res *)arg->result);
  97         if (err > 0)
  98                 err = -EAGAIN;
  99 errout:
 100         return err;
 101 }
 102
 103 static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
 104         FRA_GENERIC_POLICY,
 105 };
 106
 107 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 108 {
 109         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 110         struct flowidn *fld = &fl->u.dn;
 111         __le16 daddr = fld->daddr;
 112         __le16 saddr = fld->saddr;
 113
 114         if (((saddr ^ r->src) & r->srcmask) ||
 115             ((daddr ^ r->dst) & r->dstmask))
 116                 return 0;
 117
 118         return 1;
 119 }
 120
 121 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 122                                  struct fib_rule_hdr *frh,
 123                                  struct nlattr **tb)
 124 {
 125         int err = -EINVAL;
 126         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 127
 128         if (frh->tos)
 129                 goto  errout;
 130
 131         if (rule->table == RT_TABLE_UNSPEC) {
 132                 if (rule->action == FR_ACT_TO_TBL) {
 133                         struct dn_fib_table *table;
 134
 135                         table = dn_fib_empty_table();
 136                         if (table == NULL) {
 137                                 err = -ENOBUFS;
 138                                 goto errout;
 139                         }
 140
 141                         rule->table = table->n;
 142                 }
 143         }
 144
 145         if (frh->src_len)
 146                 r->src = nla_get_le16(tb[FRA_SRC]);
 147
 148         if (frh->dst_len)
 149                 r->dst = nla_get_le16(tb[FRA_DST]);
 150
 151         r->src_len = frh->src_len;
 152         r->srcmask = dnet_make_mask(r->src_len);
 153         r->dst_len = frh->dst_len;
 154         r->dstmask = dnet_make_mask(r->dst_len);
 155         err = 0;
 156 errout:
 157         return err;
 158 }
 159
 160 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 161                                struct nlattr **tb)
 162 {
 163         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 164
 165         if (frh->src_len && (r->src_len != frh->src_len))
 166                 return 0;
 167
 168         if (frh->dst_len && (r->dst_len != frh->dst_len))
 169                 return 0;
 170
 171         if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
 172                 return 0;
 173
 174         if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
 175                 return 0;
 176
 177         return 1;
 178 }
 179
 180 unsigned int dnet_addr_type(__le16 addr)
 181 {
 182         struct flowidn fld = { .daddr = addr };
 183         struct dn_fib_res res;
 184         unsigned int ret = RTN_UNICAST;
 185         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 186
 187         res.r = NULL;
 188
 189         if (tb) {
 190                 if (!tb->lookup(tb, &fld, &res)) {
 191                         ret = res.type;
 192                         dn_fib_res_put(&res);
 193                 }
 194         }
 195         return ret;
 196 }
 197
 198 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 199                             struct fib_rule_hdr *frh)
 200 {
 201         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 202
 203         frh->dst_len = r->dst_len;
 204         frh->src_len = r->src_len;
 205         frh->tos = 0;
 206
 207         if ((r->dst_len &&
 208              nla_put_le16(skb, FRA_DST, r->dst)) ||
 209             (r->src_len &&
 210              nla_put_le16(skb, FRA_SRC, r->src)))
 211                 goto nla_put_failure;
 212         return 0;
 213
 214 nla_put_failure:
 215         return -ENOBUFS;
 216 }
 217
 218 static void dn_fib_rule_flush_cache(struct fib_rules_ops *ops)
 219 {
 220         dn_rt_cache_flush(-1);
 221 }
 222
 223 static const struct fib_rules_ops __net_initconst dn_fib_rules_ops_template = {
 224         .family         = AF_DECnet,
 225         .rule_size      = sizeof(struct dn_fib_rule),
 226         .addr_size      = sizeof(u16),
 227         .action         = dn_fib_rule_action,
 228         .match          = dn_fib_rule_match,
 229         .configure      = dn_fib_rule_configure,
 230         .compare        = dn_fib_rule_compare,
 231         .fill           = dn_fib_rule_fill,
 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         rtnl_lock();
 251         fib_rules_unregister(dn_fib_rules_ops);
 252         rtnl_unlock();
 253         rcu_barrier();
 254 }
 255
 256