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 #ifdef CONFIG_DECNET_ROUTE_FWMARK
  49         u32                     fwmark;
  50         u32                     fwmask;
  51 #endif
  52 };
  53
  54 static struct dn_fib_rule default_rule = {
  55         .common = {
  56                 .refcnt =               ATOMIC_INIT(2),
  57                 .pref =                 0x7fff,
  58                 .table =                RT_TABLE_MAIN,
  59                 .action =               FR_ACT_TO_TBL,
  60         },
  61 };
  62
  63 static LIST_HEAD(dn_fib_rules);
  64
  65
  66 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
  67 {
  68         struct fib_lookup_arg arg = {
  69                 .result = res,
  70         };
  71         int err;
  72
  73         err = fib_rules_lookup(&dn_fib_rules_ops, flp, 0, &arg);
  74         res->r = arg.rule;
  75
  76         return err;
  77 }
  78
  79 static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  80                               int flags, struct fib_lookup_arg *arg)
  81 {
  82         int err = -EAGAIN;
  83         struct dn_fib_table *tbl;
  84
  85         switch(rule->action) {
  86         case FR_ACT_TO_TBL:
  87                 break;
  88
  89         case FR_ACT_UNREACHABLE:
  90                 err = -ENETUNREACH;
  91                 goto errout;
  92
  93         case FR_ACT_PROHIBIT:
  94                 err = -EACCES;
  95                 goto errout;
  96
  97         case FR_ACT_BLACKHOLE:
  98         default:
  99                 err = -EINVAL;
 100                 goto errout;
 101         }
 102
 103         tbl = dn_fib_get_table(rule->table, 0);
 104         if (tbl == NULL)
 105                 goto errout;
 106
 107         err = tbl->lookup(tbl, flp, (struct dn_fib_res *)arg->result);
 108         if (err > 0)
 109                 err = -EAGAIN;
 110 errout:
 111         return err;
 112 }
 113
 114 static struct nla_policy dn_fib_rule_policy[FRA_MAX+1] __read_mostly = {
 115         [FRA_IFNAME]    = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
 116         [FRA_PRIORITY]  = { .type = NLA_U32 },
 117         [FRA_SRC]       = { .type = NLA_U16 },
 118         [FRA_DST]       = { .type = NLA_U16 },
 119         [FRA_FWMARK]    = { .type = NLA_U32 },
 120         [FRA_FWMASK]    = { .type = NLA_U32 },
 121         [FRA_TABLE]     = { .type = NLA_U32 },
 122 };
 123
 124 static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 125 {
 126         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 127         u16 daddr = fl->fld_dst;
 128         u16 saddr = fl->fld_src;
 129
 130         if (((saddr ^ r->src) & r->srcmask) ||
 131             ((daddr ^ r->dst) & r->dstmask))
 132                 return 0;
 133
 134 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 135         if ((r->fwmark ^ fl->fld_fwmark) & r->fwmask)
 136                 return 0;
 137 #endif
 138
 139         return 1;
 140 }
 141
 142 static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 143                                  struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 144                                  struct nlattr **tb)
 145 {
 146         int err = -EINVAL;
 147         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 148
 149         if (frh->src_len > 16 || frh->dst_len > 16 || frh->tos)
 150                 goto  errout;
 151
 152         if (rule->table == RT_TABLE_UNSPEC) {
 153                 if (rule->action == FR_ACT_TO_TBL) {
 154                         struct dn_fib_table *table;
 155
 156                         table = dn_fib_empty_table();
 157                         if (table == NULL) {
 158                                 err = -ENOBUFS;
 159                                 goto errout;
 160                         }
 161
 162                         rule->table = table->n;
 163                 }
 164         }
 165
 166         if (tb[FRA_SRC])
 167                 r->src = nla_get_u16(tb[FRA_SRC]);
 168
 169         if (tb[FRA_DST])
 170                 r->dst = nla_get_u16(tb[FRA_DST]);
 171
 172 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 173         if (tb[FRA_FWMARK]) {
 174                 r->fwmark = nla_get_u32(tb[FRA_FWMARK]);
 175                 if (r->fwmark)
 176                         /* compatibility: if the mark value is non-zero all bits
 177                          * are compared unless a mask is explicitly specified.
 178                          */
 179                         r->fwmask = 0xFFFFFFFF;
 180         }
 181
 182         if (tb[FRA_FWMASK])
 183                 r->fwmask = nla_get_u32(tb[FRA_FWMASK]);
 184 #endif
 185
 186         r->src_len = frh->src_len;
 187         r->srcmask = dnet_make_mask(r->src_len);
 188         r->dst_len = frh->dst_len;
 189         r->dstmask = dnet_make_mask(r->dst_len);
 190         err = 0;
 191 errout:
 192         return err;
 193 }
 194
 195 static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 196                                struct nlattr **tb)
 197 {
 198         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 199
 200         if (frh->src_len && (r->src_len != frh->src_len))
 201                 return 0;
 202
 203         if (frh->dst_len && (r->dst_len != frh->dst_len))
 204                 return 0;
 205
 206 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 207         if (tb[FRA_FWMARK] && (r->fwmark != nla_get_u32(tb[FRA_FWMARK])))
 208                 return 0;
 209
 210         if (tb[FRA_FWMASK] && (r->fwmask != nla_get_u32(tb[FRA_FWMASK])))
 211                 return 0;
 212 #endif
 213
 214         if (tb[FRA_SRC] && (r->src != nla_get_u16(tb[FRA_SRC])))
 215                 return 0;
 216
 217         if (tb[FRA_DST] && (r->dst != nla_get_u16(tb[FRA_DST])))
 218                 return 0;
 219
 220         return 1;
 221 }
 222
 223 unsigned dnet_addr_type(__le16 addr)
 224 {
 225         struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
 226         struct dn_fib_res res;
 227         unsigned ret = RTN_UNICAST;
 228         struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 229
 230         res.r = NULL;
 231
 232         if (tb) {
 233                 if (!tb->lookup(tb, &fl, &res)) {
 234                         ret = res.type;
 235                         dn_fib_res_put(&res);
 236                 }
 237         }
 238         return ret;
 239 }
 240
 241 static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 242                             struct nlmsghdr *nlh, struct fib_rule_hdr *frh)
 243 {
 244         struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 245
 246         frh->family = AF_DECnet;
 247         frh->dst_len = r->dst_len;
 248         frh->src_len = r->src_len;
 249         frh->tos = 0;
 250
 251 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 252         if (r->fwmark)
 253                 NLA_PUT_U32(skb, FRA_FWMARK, r->fwmark);
 254         if (r->fwmask || r->fwmark)
 255                 NLA_PUT_U32(skb, FRA_FWMASK, r->fwmask);
 256 #endif
 257         if (r->dst_len)
 258                 NLA_PUT_U16(skb, FRA_DST, r->dst);
 259         if (r->src_len)
 260                 NLA_PUT_U16(skb, FRA_SRC, r->src);
 261
 262         return 0;
 263
 264 nla_put_failure:
 265         return -ENOBUFS;
 266 }
 267
 268 static u32 dn_fib_rule_default_pref(void)
 269 {
 270         struct list_head *pos;
 271         struct fib_rule *rule;
 272
 273         if (!list_empty(&dn_fib_rules)) {
 274                 pos = dn_fib_rules.next;
 275                 if (pos->next != &dn_fib_rules) {
 276                         rule = list_entry(pos->next, struct fib_rule, list);
 277                         if (rule->pref)
 278                                 return rule->pref - 1;
 279                 }
 280         }
 281
 282         return 0;
 283 }
 284
 285 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 286 {
 287         return fib_rules_dump(skb, cb, AF_DECnet);
 288 }
 289
 290 static struct fib_rules_ops dn_fib_rules_ops = {
 291         .family         = AF_DECnet,
 292         .rule_size      = sizeof(struct dn_fib_rule),
 293         .action         = dn_fib_rule_action,
 294         .match          = dn_fib_rule_match,
 295         .configure      = dn_fib_rule_configure,
 296         .compare        = dn_fib_rule_compare,
 297         .fill           = dn_fib_rule_fill,
 298         .default_pref   = dn_fib_rule_default_pref,
 299         .nlgroup        = RTNLGRP_DECnet_RULE,
 300         .policy         = dn_fib_rule_policy,
 301         .rules_list     = &dn_fib_rules,
 302         .owner          = THIS_MODULE,
 303 };
 304
 305 void __init dn_fib_rules_init(void)
 306 {
 307         list_add_tail(&default_rule.common.list, &dn_fib_rules);
 308         fib_rules_register(&dn_fib_rules_ops);
 309 }
 310
 311 void __exit dn_fib_rules_cleanup(void)
 312 {
 313         fib_rules_unregister(&dn_fib_rules_ops);
 314 }
 315
 316