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         u32                     fwmark;
  49         u32                     fwmask;
  50 };
  51
  52 static struct dn_fib_rule default_rule = {
  53         .common = {
  54                 .refcnt =               ATOMIC_INIT(2),
  55                 .pref =                 0x7fff,
  56                 .table =                RT_TABLE_MAIN,
  57                 .action =               FR_ACT_TO_TBL,
  58         },
  59 };
  60
  61 static LIST_HEAD(dn_fib_rules);
  62
  63
  64 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
  65 {
  66         struct fib_lookup_arg arg = {
  67                 .result = res,
  68         };
  69         int err;
  70
  71         err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
  72         res->r = arg.rule;
  73
  74         return err;
  75 }
  76
  77 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  78                               int flags, struct fib_lookup_arg *arg)
  79 {
  80         int err = -EAGAIN;
  81         struct dn_fib_table *tbl;
  82
  83         switch(rule->action) {
  84         case FR_ACT_TO_TBL:
  85                 break;
  86
  87         case FR_ACT_UNREACHABLE:
  88                 err = -ENETUNREACH;
  89                 goto errout;
  90
  91         case FR_ACT_PROHIBIT:
  92                 err = -EACCES;
  93                 goto errout;
  94
  95         case FR_ACT_BLACKHOLE:
  96         default:
  97                 err = -EINVAL;
  98                 goto errout;
  99         }
 100
 101         tbl = dn_fib_get_table(rule->table, 0);
 102         if (tbl == NULL)
 103                 goto errout;
 104
 105         err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
 106         if (err > 0)
 107                 err = -EAGAIN;
 108 errout:
 109         return err;
 110 }
 111
 112 static struct nla_policy dn_fib_rule_policy[FRA_MAX+1] __read_mostly = {
 113         [FRA_IFNAME]    = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
 114         [FRA_PRIORITY]  = { .type = NLA_U32 },
 115         [FRA_SRC]       = { .type = NLA_U16 },
 116         [FRA_DST]       = { .type = NLA_U16 },
 117         [FRA_FWMARK]    = { .type = NLA_U32 },
 118         [FRA_FWMASK]    = { .type = NLA_U32 },
 119         [FRA_TABLE]     = { .type = NLA_U32 },
 120 };
 121
 122 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 123 {
 124         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 125         __le16 daddr = fl->fld_dst;
 126         __le16 saddr = fl->fld_src;
 127
 128         if (((saddr ^ r->src) & r->srcmask) ||
 129             ((daddr ^ r->dst) & r->dstmask))
 130                 return 0;
 131
 132         if ((r->fwmark ^ fl->mark) & r->fwmask)
 133                 return 0;
 134
 135         return 1;
 136 }
 137
 138 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 139                                  struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 140                                  struct nlattr **tb)
 141 {
 142         int err = -EINVAL;
 143         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 144
 145         if (frh->src_len > 16 || frh->dst_len > 16 || frh->tos)
 146                 goto  errout;
 147
 148         if (rule->table == RT_TABLE_UNSPEC) {
 149                 if (rule->action == FR_ACT_TO_TBL) {
 150                         struct dn_fib_table *table;
 151
 152                         table = dn_fib_empty_table();
 153                         if (table == NULL) {
 154                                 err = -ENOBUFS;
 155                                 goto errout;
 156                         }
 157
 158                         rule->table = table->n;
 159                 }
 160         }
 161
 162         if (tb[FRA_SRC])
 163                 r->src = nla_get_u16(tb[FRA_SRC]);
 164
 165         if (tb[FRA_DST])
 166                 r->dst = nla_get_u16(tb[FRA_DST]);
 167
 168         if (tb[FRA_FWMARK]) {
 169                 r->fwmark = nla_get_u32(tb[FRA_FWMARK]);
 170                 if (r->fwmark)
 171                         /* compatibility: if the mark value is non-zero all bits
 172                          * are compared unless a mask is explicitly specified.
 173                          */
 174                         r->fwmask = 0xFFFFFFFF;
 175         }
 176
 177         if (tb[FRA_FWMASK])
 178                 r->fwmask = nla_get_u32(tb[FRA_FWMASK]);
 179
 180         r->src_len = frh->src_len;
 181         r->srcmask = dnet_make_mask(r->src_len);
 182         r->dst_len = frh->dst_len;
 183         r->dstmask = dnet_make_mask(r->dst_len);
 184         err = 0;
 185 errout:
 186         return err;
 187 }
 188
 189 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 190                                struct nlattr **tb)
 191 {
 192         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 193
 194         if (frh->src_len && (r->src_len != frh->src_len))
 195                 return 0;
 196
 197         if (frh->dst_len && (r->dst_len != frh->dst_len))
 198                 return 0;
 199
 200         if (tb[FRA_FWMARK] && (r->fwmark != nla_get_u32(tb[FRA_FWMARK])))
 201                 return 0;
 202
 203         if (tb[FRA_FWMASK] && (r->fwmask != nla_get_u32(tb[FRA_FWMASK])))
 204                 return 0;
 205
 206         if (tb[FRA_SRC] && (r->src != nla_get_u16(tb[FRA_SRC])))
 207                 return 0;
 208
 209         if (tb[FRA_DST] && (r->dst != nla_get_u16(tb[FRA_DST])))
 210                 return 0;
 211
 212         return 1;
 213 }
 214
 215 unsigned dnet_addr_type(__le16 addr)
 216 {
 217         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 218         struct dn_fib_res res;
 219         unsigned ret = RTN_UNICAST;
 220         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 221
 222         res.r = NULL;
 223
 224         if (tb) {
 225                 if (!tb->lookup(tb, &fl, &res)) {
 226                         ret = res.type;
 227                         dn_fib_res_put(&res);
 228                 }
 229         }
 230         return ret;
 231 }
 232
 233 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 234                             struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 235 {
 236         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 237
 238         frh->family = AF_DECnet;
 239         frh->dst_len = r->dst_len;
 240         frh->src_len = r->src_len;
 241         frh->tos = 0;
 242
 243         if (r->fwmark)
 244                 NLA_PUT_U32(skb, FRA_FWMARK, r->fwmark);
 245         if (r->fwmask || r->fwmark)
 246                 NLA_PUT_U32(skb, FRA_FWMASK, r->fwmask);
 247         if (r->dst_len)
 248                 NLA_PUT_U16(skb, FRA_DST, r->dst);
 249         if (r->src_len)
 250                 NLA_PUT_U16(skb, FRA_SRC, r->src);
 251
 252         return 0;
 253
 254 nla_put_failure:
 255         return -ENOBUFS;
 256 }
 257
 258 static u32 dn_fib_rule_default_pref(void)
 259 {
 260         struct list_head *pos;
 261         struct fib_rule *rule;
 262
 263         if (!list_empty(&dn_fib_rules)) {
 264                 pos = dn_fib_rules.next;
 265                 if (pos->next != &dn_fib_rules) {
 266                         rule = list_entry(pos->next, struct fib_rule, list);
 267                         if (rule->pref)
 268                                 return rule->pref - 1;
 269                 }
 270         }
 271
 272         return 0;
 273 }
 274
 275 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 276 {
 277         return fib_rules_dump(skb, cb, AF_DECnet);
 278 }
 279
 280 static struct fib_rules_ops dn_fib_rules_ops = {
 281         .family         = AF_DECnet,
 282         .rule_size      = sizeof(struct dn_fib_rule),
 283         .action         = dn_fib_rule_action,
 284         .match          = dn_fib_rule_match,
 285         .configure      = dn_fib_rule_configure,
 286         .compare        = dn_fib_rule_compare,
 287         .fill           = dn_fib_rule_fill,
 288         .default_pref   = dn_fib_rule_default_pref,
 289         .nlgroup        = RTNLGRP_DECnet_RULE,
 290         .policy         = dn_fib_rule_policy,
 291         .rules_list     = &dn_fib_rules,
 292         .owner          = THIS_MODULE,
 293 };
 294
 295 void __init dn_fib_rules_init(void)
 296 {
 297         list_add_tail(&default_rule.common.list, &dn_fib_rules);
 298         fib_rules_register(&dn_fib_rules_ops);
 299 }
 300
 301 void __exit dn_fib_rules_cleanup(void)
 302 {
 303         fib_rules_unregister(&dn_fib_rules_ops);
 304 }
 305
 306