linux/net/decnet/dn_rules.c
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   1// SPDX-License-Identifier: GPL-2.0
   2
   3/*
   4 * DECnet       An implementation of the DECnet protocol suite for the LINUX
   5 *              operating system.  DECnet is implemented using the  BSD Socket
   6 *              interface as the means of communication with the user level.
   7 *
   8 *              DECnet Routing Forwarding Information Base (Rules)
   9 *
  10 * Author:      Steve Whitehouse <SteveW@ACM.org>
  11 *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
  12 *
  13 *
  14 * Changes:
  15 *              Steve Whitehouse <steve@chygwyn.com>
  16 *              Updated for Thomas Graf's generic rules
  17 *
  18 */
  19#include <linux/net.h>
  20#include <linux/init.h>
  21#include <linux/netlink.h>
  22#include <linux/rtnetlink.h>
  23#include <linux/netdevice.h>
  24#include <linux/spinlock.h>
  25#include <linux/list.h>
  26#include <linux/rcupdate.h>
  27#include <linux/export.h>
  28#include <net/neighbour.h>
  29#include <net/dst.h>
  30#include <net/flow.h>
  31#include <net/fib_rules.h>
  32#include <net/dn.h>
  33#include <net/dn_fib.h>
  34#include <net/dn_neigh.h>
  35#include <net/dn_dev.h>
  36#include <net/dn_route.h>
  37
  38static struct fib_rules_ops *dn_fib_rules_ops;
  39
  40struct dn_fib_rule
  41{
  42        struct fib_rule         common;
  43        unsigned char           dst_len;
  44        unsigned char           src_len;
  45        __le16                  src;
  46        __le16                  srcmask;
  47        __le16                  dst;
  48        __le16                  dstmask;
  49        __le16                  srcmap;
  50        u8                      flags;
  51};
  52
  53
  54int dn_fib_lookup(struct flowidn *flp, struct dn_fib_res *res)
  55{
  56        struct fib_lookup_arg arg = {
  57                .result = res,
  58        };
  59        int err;
  60
  61        err = fib_rules_lookup(dn_fib_rules_ops,
  62                               flowidn_to_flowi(flp), 0, &arg);
  63        res->r = arg.rule;
  64
  65        return err;
  66}
  67
  68static int dn_fib_rule_action(struct fib_rule *rule, struct flowi *flp,
  69                              int flags, struct fib_lookup_arg *arg)
  70{
  71        struct flowidn *fld = &flp->u.dn;
  72        int err = -EAGAIN;
  73        struct dn_fib_table *tbl;
  74
  75        switch(rule->action) {
  76        case FR_ACT_TO_TBL:
  77                break;
  78
  79        case FR_ACT_UNREACHABLE:
  80                err = -ENETUNREACH;
  81                goto errout;
  82
  83        case FR_ACT_PROHIBIT:
  84                err = -EACCES;
  85                goto errout;
  86
  87        case FR_ACT_BLACKHOLE:
  88        default:
  89                err = -EINVAL;
  90                goto errout;
  91        }
  92
  93        tbl = dn_fib_get_table(rule->table, 0);
  94        if (tbl == NULL)
  95                goto errout;
  96
  97        err = tbl->lookup(tbl, fld, (struct dn_fib_res *)arg->result);
  98        if (err > 0)
  99                err = -EAGAIN;
 100errout:
 101        return err;
 102}
 103
 104static const struct nla_policy dn_fib_rule_policy[FRA_MAX+1] = {
 105        FRA_GENERIC_POLICY,
 106};
 107
 108static int dn_fib_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
 109{
 110        struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 111        struct flowidn *fld = &fl->u.dn;
 112        __le16 daddr = fld->daddr;
 113        __le16 saddr = fld->saddr;
 114
 115        if (((saddr ^ r->src) & r->srcmask) ||
 116            ((daddr ^ r->dst) & r->dstmask))
 117                return 0;
 118
 119        return 1;
 120}
 121
 122static int dn_fib_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 123                                 struct fib_rule_hdr *frh,
 124                                 struct nlattr **tb,
 125                                 struct netlink_ext_ack *extack)
 126{
 127        int err = -EINVAL;
 128        struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 129
 130        if (frh->tos) {
 131                NL_SET_ERR_MSG(extack, "Invalid tos value");
 132                goto  errout;
 133        }
 134
 135        if (rule->table == RT_TABLE_UNSPEC) {
 136                if (rule->action == FR_ACT_TO_TBL) {
 137                        struct dn_fib_table *table;
 138
 139                        table = dn_fib_empty_table();
 140                        if (table == NULL) {
 141                                err = -ENOBUFS;
 142                                goto errout;
 143                        }
 144
 145                        rule->table = table->n;
 146                }
 147        }
 148
 149        if (frh->src_len)
 150                r->src = nla_get_le16(tb[FRA_SRC]);
 151
 152        if (frh->dst_len)
 153                r->dst = nla_get_le16(tb[FRA_DST]);
 154
 155        r->src_len = frh->src_len;
 156        r->srcmask = dnet_make_mask(r->src_len);
 157        r->dst_len = frh->dst_len;
 158        r->dstmask = dnet_make_mask(r->dst_len);
 159        err = 0;
 160errout:
 161        return err;
 162}
 163
 164static int dn_fib_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 165                               struct nlattr **tb)
 166{
 167        struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 168
 169        if (frh->src_len && (r->src_len != frh->src_len))
 170                return 0;
 171
 172        if (frh->dst_len && (r->dst_len != frh->dst_len))
 173                return 0;
 174
 175        if (frh->src_len && (r->src != nla_get_le16(tb[FRA_SRC])))
 176                return 0;
 177
 178        if (frh->dst_len && (r->dst != nla_get_le16(tb[FRA_DST])))
 179                return 0;
 180
 181        return 1;
 182}
 183
 184unsigned int dnet_addr_type(__le16 addr)
 185{
 186        struct flowidn fld = { .daddr = addr };
 187        struct dn_fib_res res;
 188        unsigned int ret = RTN_UNICAST;
 189        struct dn_fib_table *tb = dn_fib_get_table(RT_TABLE_LOCAL, 0);
 190
 191        res.r = NULL;
 192
 193        if (tb) {
 194                if (!tb->lookup(tb, &fld, &res)) {
 195                        ret = res.type;
 196                        dn_fib_res_put(&res);
 197                }
 198        }
 199        return ret;
 200}
 201
 202static int dn_fib_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 203                            struct fib_rule_hdr *frh)
 204{
 205        struct dn_fib_rule *r = (struct dn_fib_rule *)rule;
 206
 207        frh->dst_len = r->dst_len;
 208        frh->src_len = r->src_len;
 209        frh->tos = 0;
 210
 211        if ((r->dst_len &&
 212             nla_put_le16(skb, FRA_DST, r->dst)) ||
 213            (r->src_len &&
 214             nla_put_le16(skb, FRA_SRC, r->src)))
 215                goto nla_put_failure;
 216        return 0;
 217
 218nla_put_failure:
 219        return -ENOBUFS;
 220}
 221
 222static void dn_fib_rule_flush_cache(struct fib_rules_ops *ops)
 223{
 224        dn_rt_cache_flush(-1);
 225}
 226
 227static const struct fib_rules_ops __net_initconst dn_fib_rules_ops_template = {
 228        .family         = AF_DECnet,
 229        .rule_size      = sizeof(struct dn_fib_rule),
 230        .addr_size      = sizeof(u16),
 231        .action         = dn_fib_rule_action,
 232        .match          = dn_fib_rule_match,
 233        .configure      = dn_fib_rule_configure,
 234        .compare        = dn_fib_rule_compare,
 235        .fill           = dn_fib_rule_fill,
 236        .flush_cache    = dn_fib_rule_flush_cache,
 237        .nlgroup        = RTNLGRP_DECnet_RULE,
 238        .policy         = dn_fib_rule_policy,
 239        .owner          = THIS_MODULE,
 240        .fro_net        = &init_net,
 241};
 242
 243void __init dn_fib_rules_init(void)
 244{
 245        dn_fib_rules_ops =
 246                fib_rules_register(&dn_fib_rules_ops_template, &init_net);
 247        BUG_ON(IS_ERR(dn_fib_rules_ops));
 248        BUG_ON(fib_default_rule_add(dn_fib_rules_ops, 0x7fff,
 249                                    RT_TABLE_MAIN, 0));
 250}
 251
 252void __exit dn_fib_rules_cleanup(void)
 253{
 254        rtnl_lock();
 255        fib_rules_unregister(dn_fib_rules_ops);
 256        rtnl_unlock();
 257        rcu_barrier();
 258}
 259
 260
 261