| 1 | /* |
| 2 | * INET An implementation of the TCP/IP protocol suite for the LINUX |
| 3 | * operating system. INET is implemented using the BSD Socket |
| 4 | * interface as the means of communication with the user level. |
| 5 | * |
| 6 | * IPv4 Forwarding Information Base: policy rules. |
| 7 | * |
| 8 | * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> |
| 9 | * Thomas Graf <tgraf@suug.ch> |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU General Public License |
| 13 | * as published by the Free Software Foundation; either version |
| 14 | * 2 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | * Fixes: |
| 17 | * Rani Assaf : local_rule cannot be deleted |
| 18 | * Marc Boucher : routing by fwmark |
| 19 | */ |
| 20 | |
| 21 | #include <linux/types.h> |
| 22 | #include <linux/kernel.h> |
| 23 | #include <linux/netdevice.h> |
| 24 | #include <linux/netlink.h> |
| 25 | #include <linux/inetdevice.h> |
| 26 | #include <linux/init.h> |
| 27 | #include <linux/list.h> |
| 28 | #include <linux/rcupdate.h> |
| 29 | #include <net/ip.h> |
| 30 | #include <net/route.h> |
| 31 | #include <net/tcp.h> |
| 32 | #include <net/ip_fib.h> |
| 33 | #include <net/fib_rules.h> |
| 34 | |
| 35 | static struct fib_rules_ops fib4_rules_ops; |
| 36 | |
| 37 | struct fib4_rule |
| 38 | { |
| 39 | struct fib_rule common; |
| 40 | u8 dst_len; |
| 41 | u8 src_len; |
| 42 | u8 tos; |
| 43 | __be32 src; |
| 44 | __be32 srcmask; |
| 45 | __be32 dst; |
| 46 | __be32 dstmask; |
| 47 | #ifdef CONFIG_NET_CLS_ROUTE |
| 48 | u32 tclassid; |
| 49 | #endif |
| 50 | }; |
| 51 | |
| 52 | #ifdef CONFIG_NET_CLS_ROUTE |
| 53 | u32 fib_rules_tclass(struct fib_result *res) |
| 54 | { |
| 55 | return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; |
| 56 | } |
| 57 | #endif |
| 58 | |
| 59 | int fib_lookup(struct flowi *flp, struct fib_result *res) |
| 60 | { |
| 61 | struct fib_lookup_arg arg = { |
| 62 | .result = res, |
| 63 | }; |
| 64 | int err; |
| 65 | |
| 66 | err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg); |
| 67 | res->r = arg.rule; |
| 68 | |
| 69 | return err; |
| 70 | } |
| 71 | |
| 72 | static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, |
| 73 | int flags, struct fib_lookup_arg *arg) |
| 74 | { |
| 75 | int err = -EAGAIN; |
| 76 | struct fib_table *tbl; |
| 77 | |
| 78 | switch (rule->action) { |
| 79 | case FR_ACT_TO_TBL: |
| 80 | break; |
| 81 | |
| 82 | case FR_ACT_UNREACHABLE: |
| 83 | err = -ENETUNREACH; |
| 84 | goto errout; |
| 85 | |
| 86 | case FR_ACT_PROHIBIT: |
| 87 | err = -EACCES; |
| 88 | goto errout; |
| 89 | |
| 90 | case FR_ACT_BLACKHOLE: |
| 91 | default: |
| 92 | err = -EINVAL; |
| 93 | goto errout; |
| 94 | } |
| 95 | |
| 96 | if ((tbl = fib_get_table(rule->table)) == NULL) |
| 97 | goto errout; |
| 98 | |
| 99 | err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result); |
| 100 | if (err > 0) |
| 101 | err = -EAGAIN; |
| 102 | errout: |
| 103 | return err; |
| 104 | } |
| 105 | |
| 106 | |
| 107 | void fib_select_default(const struct flowi *flp, struct fib_result *res) |
| 108 | { |
| 109 | if (res->r && res->r->action == FR_ACT_TO_TBL && |
| 110 | FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) { |
| 111 | struct fib_table *tb; |
| 112 | if ((tb = fib_get_table(res->r->table)) != NULL) |
| 113 | tb->tb_select_default(tb, flp, res); |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) |
| 118 | { |
| 119 | struct fib4_rule *r = (struct fib4_rule *) rule; |
| 120 | __be32 daddr = fl->fl4_dst; |
| 121 | __be32 saddr = fl->fl4_src; |
| 122 | |
| 123 | if (((saddr ^ r->src) & r->srcmask) || |
| 124 | ((daddr ^ r->dst) & r->dstmask)) |
| 125 | return 0; |
| 126 | |
| 127 | if (r->tos && (r->tos != fl->fl4_tos)) |
| 128 | return 0; |
| 129 | |
| 130 | return 1; |
| 131 | } |
| 132 | |
| 133 | static struct fib_table *fib_empty_table(void) |
| 134 | { |
| 135 | u32 id; |
| 136 | |
| 137 | for (id = 1; id <= RT_TABLE_MAX; id++) |
| 138 | if (fib_get_table(id) == NULL) |
| 139 | return fib_new_table(id); |
| 140 | return NULL; |
| 141 | } |
| 142 | |
| 143 | static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { |
| 144 | FRA_GENERIC_POLICY, |
| 145 | [FRA_FLOW] = { .type = NLA_U32 }, |
| 146 | }; |
| 147 | |
| 148 | static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, |
| 149 | struct nlmsghdr *nlh, struct fib_rule_hdr *frh, |
| 150 | struct nlattr **tb) |
| 151 | { |
| 152 | int err = -EINVAL; |
| 153 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
| 154 | |
| 155 | if (frh->tos & ~IPTOS_TOS_MASK) |
| 156 | goto errout; |
| 157 | |
| 158 | if (rule->table == RT_TABLE_UNSPEC) { |
| 159 | if (rule->action == FR_ACT_TO_TBL) { |
| 160 | struct fib_table *table; |
| 161 | |
| 162 | table = fib_empty_table(); |
| 163 | if (table == NULL) { |
| 164 | err = -ENOBUFS; |
| 165 | goto errout; |
| 166 | } |
| 167 | |
| 168 | rule->table = table->tb_id; |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | if (frh->src_len) |
| 173 | rule4->src = nla_get_be32(tb[FRA_SRC]); |
| 174 | |
| 175 | if (frh->dst_len) |
| 176 | rule4->dst = nla_get_be32(tb[FRA_DST]); |
| 177 | |
| 178 | #ifdef CONFIG_NET_CLS_ROUTE |
| 179 | if (tb[FRA_FLOW]) |
| 180 | rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); |
| 181 | #endif |
| 182 | |
| 183 | rule4->src_len = frh->src_len; |
| 184 | rule4->srcmask = inet_make_mask(rule4->src_len); |
| 185 | rule4->dst_len = frh->dst_len; |
| 186 | rule4->dstmask = inet_make_mask(rule4->dst_len); |
| 187 | rule4->tos = frh->tos; |
| 188 | |
| 189 | err = 0; |
| 190 | errout: |
| 191 | return err; |
| 192 | } |
| 193 | |
| 194 | static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, |
| 195 | struct nlattr **tb) |
| 196 | { |
| 197 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
| 198 | |
| 199 | if (frh->src_len && (rule4->src_len != frh->src_len)) |
| 200 | return 0; |
| 201 | |
| 202 | if (frh->dst_len && (rule4->dst_len != frh->dst_len)) |
| 203 | return 0; |
| 204 | |
| 205 | if (frh->tos && (rule4->tos != frh->tos)) |
| 206 | return 0; |
| 207 | |
| 208 | #ifdef CONFIG_NET_CLS_ROUTE |
| 209 | if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) |
| 210 | return 0; |
| 211 | #endif |
| 212 | |
| 213 | if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) |
| 214 | return 0; |
| 215 | |
| 216 | if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) |
| 217 | return 0; |
| 218 | |
| 219 | return 1; |
| 220 | } |
| 221 | |
| 222 | static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, |
| 223 | struct nlmsghdr *nlh, struct fib_rule_hdr *frh) |
| 224 | { |
| 225 | struct fib4_rule *rule4 = (struct fib4_rule *) rule; |
| 226 | |
| 227 | frh->family = AF_INET; |
| 228 | frh->dst_len = rule4->dst_len; |
| 229 | frh->src_len = rule4->src_len; |
| 230 | frh->tos = rule4->tos; |
| 231 | |
| 232 | if (rule4->dst_len) |
| 233 | NLA_PUT_BE32(skb, FRA_DST, rule4->dst); |
| 234 | |
| 235 | if (rule4->src_len) |
| 236 | NLA_PUT_BE32(skb, FRA_SRC, rule4->src); |
| 237 | |
| 238 | #ifdef CONFIG_NET_CLS_ROUTE |
| 239 | if (rule4->tclassid) |
| 240 | NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); |
| 241 | #endif |
| 242 | return 0; |
| 243 | |
| 244 | nla_put_failure: |
| 245 | return -ENOBUFS; |
| 246 | } |
| 247 | |
| 248 | static u32 fib4_rule_default_pref(struct fib_rules_ops *ops) |
| 249 | { |
| 250 | struct list_head *pos; |
| 251 | struct fib_rule *rule; |
| 252 | |
| 253 | if (!list_empty(&fib4_rules_ops.rules_list)) { |
| 254 | pos = fib4_rules_ops.rules_list.next; |
| 255 | if (pos->next != &fib4_rules_ops.rules_list) { |
| 256 | rule = list_entry(pos->next, struct fib_rule, list); |
| 257 | if (rule->pref) |
| 258 | return rule->pref - 1; |
| 259 | } |
| 260 | } |
| 261 | |
| 262 | return 0; |
| 263 | } |
| 264 | |
| 265 | static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) |
| 266 | { |
| 267 | return nla_total_size(4) /* dst */ |
| 268 | + nla_total_size(4) /* src */ |
| 269 | + nla_total_size(4); /* flow */ |
| 270 | } |
| 271 | |
| 272 | static void fib4_rule_flush_cache(void) |
| 273 | { |
| 274 | rt_cache_flush(-1); |
| 275 | } |
| 276 | |
| 277 | static struct fib_rules_ops fib4_rules_ops = { |
| 278 | .family = AF_INET, |
| 279 | .rule_size = sizeof(struct fib4_rule), |
| 280 | .addr_size = sizeof(u32), |
| 281 | .action = fib4_rule_action, |
| 282 | .match = fib4_rule_match, |
| 283 | .configure = fib4_rule_configure, |
| 284 | .compare = fib4_rule_compare, |
| 285 | .fill = fib4_rule_fill, |
| 286 | .default_pref = fib4_rule_default_pref, |
| 287 | .nlmsg_payload = fib4_rule_nlmsg_payload, |
| 288 | .flush_cache = fib4_rule_flush_cache, |
| 289 | .nlgroup = RTNLGRP_IPV4_RULE, |
| 290 | .policy = fib4_rule_policy, |
| 291 | .rules_list = LIST_HEAD_INIT(fib4_rules_ops.rules_list), |
| 292 | .owner = THIS_MODULE, |
| 293 | }; |
| 294 | |
| 295 | static int __init fib_default_rules_init(void) |
| 296 | { |
| 297 | int err; |
| 298 | |
| 299 | err = fib_default_rule_add(&fib4_rules_ops, 0, |
| 300 | RT_TABLE_LOCAL, FIB_RULE_PERMANENT); |
| 301 | if (err < 0) |
| 302 | return err; |
| 303 | err = fib_default_rule_add(&fib4_rules_ops, 0x7FFE, |
| 304 | RT_TABLE_MAIN, 0); |
| 305 | if (err < 0) |
| 306 | return err; |
| 307 | err = fib_default_rule_add(&fib4_rules_ops, 0x7FFF, |
| 308 | RT_TABLE_DEFAULT, 0); |
| 309 | if (err < 0) |
| 310 | return err; |
| 311 | return 0; |
| 312 | } |
| 313 | |
| 314 | int __net_init fib4_rules_init(struct net *net) |
| 315 | { |
| 316 | int err; |
| 317 | |
| 318 | fib_rules_register(net, &fib4_rules_ops); |
| 319 | err = fib_default_rules_init(); |
| 320 | if (err < 0) |
| 321 | goto fail; |
| 322 | return 0; |
| 323 | |
| 324 | fail: |
| 325 | /* also cleans all rules already added */ |
| 326 | fib_rules_unregister(net, &fib4_rules_ops); |
| 327 | return err; |
| 328 | } |
| 329 | |
| 330 | void __net_exit fib4_rules_exit(struct net *net) |
| 331 | { |
| 332 | fib_rules_unregister(net, &fib4_rules_ops); |
| 333 | } |