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 static struct fib4_rule default_rule = { 53 .common = { 54 .refcnt = ATOMIC_INIT(2), 55 .pref = 0x7FFF, 56 .table = RT_TABLE_DEFAULT, 57 .action = FR_ACT_TO_TBL, 58 }, 59 }; 60 61 static struct fib4_rule main_rule = { 62 .common = { 63 .refcnt = ATOMIC_INIT(2), 64 .pref = 0x7FFE, 65 .table = RT_TABLE_MAIN, 66 .action = FR_ACT_TO_TBL, 67 }, 68 }; 69 70 static struct fib4_rule local_rule = { 71 .common = { 72 .refcnt = ATOMIC_INIT(2), 73 .table = RT_TABLE_LOCAL, 74 .action = FR_ACT_TO_TBL, 75 .flags = FIB_RULE_PERMANENT, 76 }, 77 }; 78 79 static LIST_HEAD(fib4_rules); 80 81 #ifdef CONFIG_NET_CLS_ROUTE 82 u32 fib_rules_tclass(struct fib_result *res) 83 { 84 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; 85 } 86 #endif 87 88 int fib_lookup(struct flowi *flp, struct fib_result *res) 89 { 90 struct fib_lookup_arg arg = { 91 .result = res, 92 }; 93 int err; 94 95 err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg); 96 res->r = arg.rule; 97 98 return err; 99 } 100 101 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 102 int flags, struct fib_lookup_arg *arg) 103 { 104 int err = -EAGAIN; 105 struct fib_table *tbl; 106 107 switch (rule->action) { 108 case FR_ACT_TO_TBL: 109 break; 110 111 case FR_ACT_UNREACHABLE: 112 err = -ENETUNREACH; 113 goto errout; 114 115 case FR_ACT_PROHIBIT: 116 err = -EACCES; 117 goto errout; 118 119 case FR_ACT_BLACKHOLE: 120 default: 121 err = -EINVAL; 122 goto errout; 123 } 124 125 if ((tbl = fib_get_table(rule->table)) == NULL) 126 goto errout; 127 128 err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result); 129 if (err > 0) 130 err = -EAGAIN; 131 errout: 132 return err; 133 } 134 135 136 void fib_select_default(const struct flowi *flp, struct fib_result *res) 137 { 138 if (res->r && res->r->action == FR_ACT_TO_TBL && 139 FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) { 140 struct fib_table *tb; 141 if ((tb = fib_get_table(res->r->table)) != NULL) 142 tb->tb_select_default(tb, flp, res); 143 } 144 } 145 146 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 147 { 148 struct fib4_rule *r = (struct fib4_rule *) rule; 149 __be32 daddr = fl->fl4_dst; 150 __be32 saddr = fl->fl4_src; 151 152 if (((saddr ^ r->src) & r->srcmask) || 153 ((daddr ^ r->dst) & r->dstmask)) 154 return 0; 155 156 if (r->tos && (r->tos != fl->fl4_tos)) 157 return 0; 158 159 return 1; 160 } 161 162 static struct fib_table *fib_empty_table(void) 163 { 164 u32 id; 165 166 for (id = 1; id <= RT_TABLE_MAX; id++) 167 if (fib_get_table(id) == NULL) 168 return fib_new_table(id); 169 return NULL; 170 } 171 172 static struct nla_policy fib4_rule_policy[FRA_MAX+1] __read_mostly = { 173 FRA_GENERIC_POLICY, 174 [FRA_SRC] = { .type = NLA_U32 }, 175 [FRA_DST] = { .type = NLA_U32 }, 176 [FRA_FLOW] = { .type = NLA_U32 }, 177 }; 178 179 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 180 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 181 struct nlattr **tb) 182 { 183 int err = -EINVAL; 184 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 185 186 if (frh->src_len > 32 || frh->dst_len > 32 || 187 (frh->tos & ~IPTOS_TOS_MASK)) 188 goto errout; 189 190 if (rule->table == RT_TABLE_UNSPEC) { 191 if (rule->action == FR_ACT_TO_TBL) { 192 struct fib_table *table; 193 194 table = fib_empty_table(); 195 if (table == NULL) { 196 err = -ENOBUFS; 197 goto errout; 198 } 199 200 rule->table = table->tb_id; 201 } 202 } 203 204 if (tb[FRA_SRC]) 205 rule4->src = nla_get_be32(tb[FRA_SRC]); 206 207 if (tb[FRA_DST]) 208 rule4->dst = nla_get_be32(tb[FRA_DST]); 209 210 #ifdef CONFIG_NET_CLS_ROUTE 211 if (tb[FRA_FLOW]) 212 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 213 #endif 214 215 rule4->src_len = frh->src_len; 216 rule4->srcmask = inet_make_mask(rule4->src_len); 217 rule4->dst_len = frh->dst_len; 218 rule4->dstmask = inet_make_mask(rule4->dst_len); 219 rule4->tos = frh->tos; 220 221 err = 0; 222 errout: 223 return err; 224 } 225 226 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 227 struct nlattr **tb) 228 { 229 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 230 231 if (frh->src_len && (rule4->src_len != frh->src_len)) 232 return 0; 233 234 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 235 return 0; 236 237 if (frh->tos && (rule4->tos != frh->tos)) 238 return 0; 239 240 #ifdef CONFIG_NET_CLS_ROUTE 241 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 242 return 0; 243 #endif 244 245 if (tb[FRA_SRC] && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 246 return 0; 247 248 if (tb[FRA_DST] && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 249 return 0; 250 251 return 1; 252 } 253 254 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 255 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 256 { 257 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 258 259 frh->family = AF_INET; 260 frh->dst_len = rule4->dst_len; 261 frh->src_len = rule4->src_len; 262 frh->tos = rule4->tos; 263 264 if (rule4->dst_len) 265 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 266 267 if (rule4->src_len) 268 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 269 270 #ifdef CONFIG_NET_CLS_ROUTE 271 if (rule4->tclassid) 272 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 273 #endif 274 return 0; 275 276 nla_put_failure: 277 return -ENOBUFS; 278 } 279 280 int fib4_rules_dump(struct sk_buff *skb, struct netlink_callback *cb) 281 { 282 return fib_rules_dump(skb, cb, AF_INET); 283 } 284 285 static u32 fib4_rule_default_pref(void) 286 { 287 struct list_head *pos; 288 struct fib_rule *rule; 289 290 if (!list_empty(&fib4_rules)) { 291 pos = fib4_rules.next; 292 if (pos->next != &fib4_rules) { 293 rule = list_entry(pos->next, struct fib_rule, list); 294 if (rule->pref) 295 return rule->pref - 1; 296 } 297 } 298 299 return 0; 300 } 301 302 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 303 { 304 return nla_total_size(4) /* dst */ 305 + nla_total_size(4) /* src */ 306 + nla_total_size(4); /* flow */ 307 } 308 309 static struct fib_rules_ops fib4_rules_ops = { 310 .family = AF_INET, 311 .rule_size = sizeof(struct fib4_rule), 312 .action = fib4_rule_action, 313 .match = fib4_rule_match, 314 .configure = fib4_rule_configure, 315 .compare = fib4_rule_compare, 316 .fill = fib4_rule_fill, 317 .default_pref = fib4_rule_default_pref, 318 .nlmsg_payload = fib4_rule_nlmsg_payload, 319 .nlgroup = RTNLGRP_IPV4_RULE, 320 .policy = fib4_rule_policy, 321 .rules_list = &fib4_rules, 322 .owner = THIS_MODULE, 323 }; 324 325 void __init fib4_rules_init(void) 326 { 327 list_add_tail(&local_rule.common.list, &fib4_rules); 328 list_add_tail(&main_rule.common.list, &fib4_rules); 329 list_add_tail(&default_rule.common.list, &fib4_rules); 330 331 fib_rules_register(&fib4_rules_ops); 332 } 333