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 #ifdef CONFIG_NET_CLS_ROUTE 80 u32 fib_rules_tclass(struct fib_result *res) 81 { 82 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; 83 } 84 #endif 85 86 int fib_lookup(struct flowi *flp, struct fib_result *res) 87 { 88 struct fib_lookup_arg arg = { 89 .result = res, 90 }; 91 int err; 92 93 err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg); 94 res->r = arg.rule; 95 96 return err; 97 } 98 99 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 100 int flags, struct fib_lookup_arg *arg) 101 { 102 int err = -EAGAIN; 103 struct fib_table *tbl; 104 105 switch (rule->action) { 106 case FR_ACT_TO_TBL: 107 break; 108 109 case FR_ACT_UNREACHABLE: 110 err = -ENETUNREACH; 111 goto errout; 112 113 case FR_ACT_PROHIBIT: 114 err = -EACCES; 115 goto errout; 116 117 case FR_ACT_BLACKHOLE: 118 default: 119 err = -EINVAL; 120 goto errout; 121 } 122 123 if ((tbl = fib_get_table(rule->table)) == NULL) 124 goto errout; 125 126 err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result); 127 if (err > 0) 128 err = -EAGAIN; 129 errout: 130 return err; 131 } 132 133 134 void fib_select_default(const struct flowi *flp, struct fib_result *res) 135 { 136 if (res->r && res->r->action == FR_ACT_TO_TBL && 137 FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) { 138 struct fib_table *tb; 139 if ((tb = fib_get_table(res->r->table)) != NULL) 140 tb->tb_select_default(tb, flp, res); 141 } 142 } 143 144 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 145 { 146 struct fib4_rule *r = (struct fib4_rule *) rule; 147 __be32 daddr = fl->fl4_dst; 148 __be32 saddr = fl->fl4_src; 149 150 if (((saddr ^ r->src) & r->srcmask) || 151 ((daddr ^ r->dst) & r->dstmask)) 152 return 0; 153 154 if (r->tos && (r->tos != fl->fl4_tos)) 155 return 0; 156 157 return 1; 158 } 159 160 static struct fib_table *fib_empty_table(void) 161 { 162 u32 id; 163 164 for (id = 1; id <= RT_TABLE_MAX; id++) 165 if (fib_get_table(id) == NULL) 166 return fib_new_table(id); 167 return NULL; 168 } 169 170 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 171 FRA_GENERIC_POLICY, 172 [FRA_FLOW] = { .type = NLA_U32 }, 173 }; 174 175 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 176 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 177 struct nlattr **tb) 178 { 179 int err = -EINVAL; 180 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 181 182 if (frh->tos & ~IPTOS_TOS_MASK) 183 goto errout; 184 185 if (rule->table == RT_TABLE_UNSPEC) { 186 if (rule->action == FR_ACT_TO_TBL) { 187 struct fib_table *table; 188 189 table = fib_empty_table(); 190 if (table == NULL) { 191 err = -ENOBUFS; 192 goto errout; 193 } 194 195 rule->table = table->tb_id; 196 } 197 } 198 199 if (frh->src_len) 200 rule4->src = nla_get_be32(tb[FRA_SRC]); 201 202 if (frh->dst_len) 203 rule4->dst = nla_get_be32(tb[FRA_DST]); 204 205 #ifdef CONFIG_NET_CLS_ROUTE 206 if (tb[FRA_FLOW]) 207 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 208 #endif 209 210 rule4->src_len = frh->src_len; 211 rule4->srcmask = inet_make_mask(rule4->src_len); 212 rule4->dst_len = frh->dst_len; 213 rule4->dstmask = inet_make_mask(rule4->dst_len); 214 rule4->tos = frh->tos; 215 216 err = 0; 217 errout: 218 return err; 219 } 220 221 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 222 struct nlattr **tb) 223 { 224 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 225 226 if (frh->src_len && (rule4->src_len != frh->src_len)) 227 return 0; 228 229 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 230 return 0; 231 232 if (frh->tos && (rule4->tos != frh->tos)) 233 return 0; 234 235 #ifdef CONFIG_NET_CLS_ROUTE 236 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 237 return 0; 238 #endif 239 240 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 241 return 0; 242 243 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 244 return 0; 245 246 return 1; 247 } 248 249 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 250 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 251 { 252 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 253 254 frh->family = AF_INET; 255 frh->dst_len = rule4->dst_len; 256 frh->src_len = rule4->src_len; 257 frh->tos = rule4->tos; 258 259 if (rule4->dst_len) 260 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 261 262 if (rule4->src_len) 263 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 264 265 #ifdef CONFIG_NET_CLS_ROUTE 266 if (rule4->tclassid) 267 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 268 #endif 269 return 0; 270 271 nla_put_failure: 272 return -ENOBUFS; 273 } 274 275 static u32 fib4_rule_default_pref(void) 276 { 277 struct list_head *pos; 278 struct fib_rule *rule; 279 280 if (!list_empty(&fib4_rules_ops.rules_list)) { 281 pos = fib4_rules_ops.rules_list.next; 282 if (pos->next != &fib4_rules_ops.rules_list) { 283 rule = list_entry(pos->next, struct fib_rule, list); 284 if (rule->pref) 285 return rule->pref - 1; 286 } 287 } 288 289 return 0; 290 } 291 292 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 293 { 294 return nla_total_size(4) /* dst */ 295 + nla_total_size(4) /* src */ 296 + nla_total_size(4); /* flow */ 297 } 298 299 static void fib4_rule_flush_cache(void) 300 { 301 rt_cache_flush(-1); 302 } 303 304 static struct fib_rules_ops fib4_rules_ops = { 305 .family = AF_INET, 306 .rule_size = sizeof(struct fib4_rule), 307 .addr_size = sizeof(u32), 308 .action = fib4_rule_action, 309 .match = fib4_rule_match, 310 .configure = fib4_rule_configure, 311 .compare = fib4_rule_compare, 312 .fill = fib4_rule_fill, 313 .default_pref = fib4_rule_default_pref, 314 .nlmsg_payload = fib4_rule_nlmsg_payload, 315 .flush_cache = fib4_rule_flush_cache, 316 .nlgroup = RTNLGRP_IPV4_RULE, 317 .policy = fib4_rule_policy, 318 .rules_list = LIST_HEAD_INIT(fib4_rules_ops.rules_list), 319 .owner = THIS_MODULE, 320 }; 321 322 void __init fib4_rules_init(void) 323 { 324 list_add_tail(&local_rule.common.list, &fib4_rules_ops.rules_list); 325 list_add_tail(&main_rule.common.list, &fib4_rules_ops.rules_list); 326 list_add_tail(&default_rule.common.list, &fib4_rules_ops.rules_list); 327 328 fib_rules_register(&fib4_rules_ops); 329 } 330