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(void) 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 void __init fib4_rules_init(void) 315 { 316 BUG_ON(fib_default_rules_init()); 317 fib_rules_register(&fib4_rules_ops); 318 } 319