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
  35 static struct fib_rules_ops dn_fib_rules_ops;
  36
  37 struct dn_fib_rule
  38 {
  39         struct fib_rule         common;
  40         unsigned char           dst_len;
  41         unsigned char           src_len;
  42         __le16                  src;
  43         __le16                  srcmask;
  44         __le16                  dst;
  45         __le16                  dstmask;
  46         __le16                  srcmap;
  47         u8                      flags;
  48 };
  49
  50 static struct dn_fib_rule default_rule = {
  51         .common = {
  52                 .refcnt =               ATOMIC_INIT(2),
  53                 .pref =                 0x7fff,
  54                 .table =                RT_TABLE_MAIN,
  55                 .action =               FR_ACT_TO_TBL,
  56         },
  57 };
  58
  59 static LIST_HEAD(dn_fib_rules);
  60
  61
  62 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
  63 {
  64         struct fib_lookup_arg arg = {
  65                 .result = res,
  66         };
  67         int err;
  68
  69         err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
  70         res->r = arg.rule;
  71
  72         return err;
  73 }
  74
  75 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  76                               int flags, struct fib_lookup_arg *arg)
  77 {
  78         int err = -EAGAIN;
  79         struct dn_fib_table *tbl;
  80
  81         switch(rule->action) {
  82         case FR_ACT_TO_TBL:
  83                 break;
  84
  85         case FR_ACT_UNREACHABLE:
  86                 err = -ENETUNREACH;
  87                 goto errout;
  88
  89         case FR_ACT_PROHIBIT:
  90                 err = -EACCES;
  91                 goto errout;
  92
  93         case FR_ACT_BLACKHOLE:
  94         default:
  95                 err = -EINVAL;
  96                 goto errout;
  97         }
  98
  99         tbl = dn_fib_get_table(rule->table, 0);
 100         if (tbl == NULL)
 101                 goto errout;
 102
 103         err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
 104         if (err > 0)
 105                 err = -EAGAIN;
 106 errout:
 107         return err;
 108 }
 109
 110 static struct nla_policy dn_fib_rule_policy[FRA_MAX+1] __read_mostly = {
 111         FRA_GENERIC_POLICY,
 112         [FRA_SRC]       = { .type = NLA_U16 },
 113         [FRA_DST]       = { .type = NLA_U16 },
 114 };
 115
 116 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 117 {
 118         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 119         __le16 daddr = fl->fld_dst;
 120         __le16 saddr = fl->fld_src;
 121
 122         if (((saddr ^ r->src) & r->srcmask) ||
 123             ((daddr ^ r->dst) & r->dstmask))
 124                 return 0;
 125
 126         return 1;
 127 }
 128
 129 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 130                                  struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 131                                  struct nlattr **tb)
 132 {
 133         int err = -EINVAL;
 134         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 135
 136         if (frh->src_len > 16 || frh->dst_len > 16 || frh->tos)
 137                 goto  errout;
 138
 139         if (rule->table == RT_TABLE_UNSPEC) {
 140                 if (rule->action == FR_ACT_TO_TBL) {
 141                         struct dn_fib_table *table;
 142
 143                         table = dn_fib_empty_table();
 144                         if (table == NULL) {
 145                                 err = -ENOBUFS;
 146                                 goto errout;
 147                         }
 148
 149                         rule->table = table->n;
 150                 }
 151         }
 152
 153         if (tb[FRA_SRC])
 154                 r->src = nla_get_u16(tb[FRA_SRC]);
 155
 156         if (tb[FRA_DST])
 157                 r->dst = nla_get_u16(tb[FRA_DST]);
 158
 159         r->src_len = frh->src_len;
 160         r->srcmask = dnet_make_mask(r->src_len);
 161         r->dst_len = frh->dst_len;
 162         r->dstmask = dnet_make_mask(r->dst_len);
 163         err = 0;
 164 errout:
 165         return err;
 166 }
 167
 168 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 169                                struct nlattr **tb)
 170 {
 171         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 172
 173         if (frh->src_len && (r->src_len != frh->src_len))
 174                 return 0;
 175
 176         if (frh->dst_len && (r->dst_len != frh->dst_len))
 177                 return 0;
 178
 179         if (tb[FRA_SRC] && (r->src != nla_get_u16(tb[FRA_SRC])))
 180                 return 0;
 181
 182         if (tb[FRA_DST] && (r->dst != nla_get_u16(tb[FRA_DST])))
 183                 return 0;
 184
 185         return 1;
 186 }
 187
 188 unsigned dnet_addr_type(__le16 addr)
 189 {
 190         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 191         struct dn_fib_res res;
 192         unsigned ret = RTN_UNICAST;
 193         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 194
 195         res.r = NULL;
 196
 197         if (tb) {
 198                 if (!tb->lookup(tb, &fl, &res)) {
 199                         ret = res.type;
 200                         dn_fib_res_put(&res);
 201                 }
 202         }
 203         return ret;
 204 }
 205
 206 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 207                             struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 208 {
 209         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 210
 211         frh->family = AF_DECnet;
 212         frh->dst_len = r->dst_len;
 213         frh->src_len = r->src_len;
 214         frh->tos = 0;
 215
 216         if (r->dst_len)
 217                 NLA_PUT_U16(skb, FRA_DST, r->dst);
 218         if (r->src_len)
 219                 NLA_PUT_U16(skb, FRA_SRC, r->src);
 220
 221         return 0;
 222
 223 nla_put_failure:
 224         return -ENOBUFS;
 225 }
 226
 227 static u32 dn_fib_rule_default_pref(void)
 228 {
 229         struct list_head *pos;
 230         struct fib_rule *rule;
 231
 232         if (!list_empty(&dn_fib_rules)) {
 233                 pos = dn_fib_rules.next;
 234                 if (pos->next != &dn_fib_rules) {
 235                         rule = list_entry(pos->next, struct fib_rule, list);
 236                         if (rule->pref)
 237                                 return rule->pref - 1;
 238                 }
 239         }
 240
 241         return 0;
 242 }
 243
 244 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 245 {
 246         return fib_rules_dump(skb, cb, AF_DECnet);
 247 }
 248
 249 static struct fib_rules_ops dn_fib_rules_ops = {
 250         .family         = AF_DECnet,
 251         .rule_size      = sizeof(struct dn_fib_rule),
 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         .nlgroup        = RTNLGRP_DECnet_RULE,
 259         .policy         = dn_fib_rule_policy,
 260         .rules_list     = &dn_fib_rules,
 261         .owner          = THIS_MODULE,
 262 };
 263
 264 void __init dn_fib_rules_init(void)
 265 {
 266         list_add_tail(&default_rule.common.list, &dn_fib_rules);
 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