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 <linux/export.h> 30 #include <net/ip.h> 31 #include <net/route.h> 32 #include <net/tcp.h> 33 #include <net/ip_fib.h> 34 #include <net/fib_rules.h> 35 36 struct fib4_rule { 37 struct fib_rule common; 38 u8 dst_len; 39 u8 src_len; 40 u8 tos; 41 __be32 src; 42 __be32 srcmask; 43 __be32 dst; 44 __be32 dstmask; 45 #ifdef CONFIG_IP_ROUTE_CLASSID 46 u32 tclassid; 47 #endif 48 }; 49 50 int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res) 51 { 52 struct fib_lookup_arg arg = { 53 .result = res, 54 .flags = FIB_LOOKUP_NOREF, 55 }; 56 int err; 57 58 err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg); 59 #ifdef CONFIG_IP_ROUTE_CLASSID 60 if (arg.rule) 61 res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid; 62 else 63 res->tclassid = 0; 64 #endif 65 return err; 66 } 67 EXPORT_SYMBOL_GPL(__fib_lookup); 68 69 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 70 int flags, struct fib_lookup_arg *arg) 71 { 72 int err = -EAGAIN; 73 struct 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 = fib_get_table(rule->fr_net, rule->table); 94 if (!tbl) 95 goto errout; 96 97 err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags); 98 if (err > 0) 99 err = -EAGAIN; 100 errout: 101 return err; 102 } 103 104 105 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 106 { 107 struct fib4_rule *r = (struct fib4_rule *) rule; 108 struct flowi4 *fl4 = &fl->u.ip4; 109 __be32 daddr = fl4->daddr; 110 __be32 saddr = fl4->saddr; 111 112 if (((saddr ^ r->src) & r->srcmask) || 113 ((daddr ^ r->dst) & r->dstmask)) 114 return 0; 115 116 if (r->tos && (r->tos != fl4->flowi4_tos)) 117 return 0; 118 119 return 1; 120 } 121 122 static struct fib_table *fib_empty_table(struct net *net) 123 { 124 u32 id; 125 126 for (id = 1; id <= RT_TABLE_MAX; id++) 127 if (fib_get_table(net, id) == NULL) 128 return fib_new_table(net, id); 129 return NULL; 130 } 131 132 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 133 FRA_GENERIC_POLICY, 134 [FRA_FLOW] = { .type = NLA_U32 }, 135 }; 136 137 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 138 struct fib_rule_hdr *frh, 139 struct nlattr **tb) 140 { 141 struct net *net = sock_net(skb->sk); 142 int err = -EINVAL; 143 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 144 145 if (frh->tos & ~IPTOS_TOS_MASK) 146 goto errout; 147 148 if (rule->table == RT_TABLE_UNSPEC) { 149 if (rule->action == FR_ACT_TO_TBL) { 150 struct fib_table *table; 151 152 table = fib_empty_table(net); 153 if (table == NULL) { 154 err = -ENOBUFS; 155 goto errout; 156 } 157 158 rule->table = table->tb_id; 159 } 160 } 161 162 if (frh->src_len) 163 rule4->src = nla_get_be32(tb[FRA_SRC]); 164 165 if (frh->dst_len) 166 rule4->dst = nla_get_be32(tb[FRA_DST]); 167 168 #ifdef CONFIG_IP_ROUTE_CLASSID 169 if (tb[FRA_FLOW]) { 170 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 171 if (rule4->tclassid) 172 net->ipv4.fib_num_tclassid_users++; 173 } 174 #endif 175 176 rule4->src_len = frh->src_len; 177 rule4->srcmask = inet_make_mask(rule4->src_len); 178 rule4->dst_len = frh->dst_len; 179 rule4->dstmask = inet_make_mask(rule4->dst_len); 180 rule4->tos = frh->tos; 181 182 net->ipv4.fib_has_custom_rules = true; 183 err = 0; 184 errout: 185 return err; 186 } 187 188 static void fib4_rule_delete(struct fib_rule *rule) 189 { 190 struct net *net = rule->fr_net; 191 #ifdef CONFIG_IP_ROUTE_CLASSID 192 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 193 194 if (rule4->tclassid) 195 net->ipv4.fib_num_tclassid_users--; 196 #endif 197 net->ipv4.fib_has_custom_rules = true; 198 } 199 200 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 201 struct nlattr **tb) 202 { 203 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 204 205 if (frh->src_len && (rule4->src_len != frh->src_len)) 206 return 0; 207 208 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 209 return 0; 210 211 if (frh->tos && (rule4->tos != frh->tos)) 212 return 0; 213 214 #ifdef CONFIG_IP_ROUTE_CLASSID 215 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 216 return 0; 217 #endif 218 219 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 220 return 0; 221 222 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 223 return 0; 224 225 return 1; 226 } 227 228 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 229 struct fib_rule_hdr *frh) 230 { 231 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 232 233 frh->dst_len = rule4->dst_len; 234 frh->src_len = rule4->src_len; 235 frh->tos = rule4->tos; 236 237 if ((rule4->dst_len && 238 nla_put_be32(skb, FRA_DST, rule4->dst)) || 239 (rule4->src_len && 240 nla_put_be32(skb, FRA_SRC, rule4->src))) 241 goto nla_put_failure; 242 #ifdef CONFIG_IP_ROUTE_CLASSID 243 if (rule4->tclassid && 244 nla_put_u32(skb, FRA_FLOW, rule4->tclassid)) 245 goto nla_put_failure; 246 #endif 247 return 0; 248 249 nla_put_failure: 250 return -ENOBUFS; 251 } 252 253 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 254 { 255 return nla_total_size(4) /* dst */ 256 + nla_total_size(4) /* src */ 257 + nla_total_size(4); /* flow */ 258 } 259 260 static void fib4_rule_flush_cache(struct fib_rules_ops *ops) 261 { 262 rt_cache_flush(ops->fro_net); 263 } 264 265 static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = { 266 .family = AF_INET, 267 .rule_size = sizeof(struct fib4_rule), 268 .addr_size = sizeof(u32), 269 .action = fib4_rule_action, 270 .match = fib4_rule_match, 271 .configure = fib4_rule_configure, 272 .delete = fib4_rule_delete, 273 .compare = fib4_rule_compare, 274 .fill = fib4_rule_fill, 275 .default_pref = fib_default_rule_pref, 276 .nlmsg_payload = fib4_rule_nlmsg_payload, 277 .flush_cache = fib4_rule_flush_cache, 278 .nlgroup = RTNLGRP_IPV4_RULE, 279 .policy = fib4_rule_policy, 280 .owner = THIS_MODULE, 281 }; 282 283 static int fib_default_rules_init(struct fib_rules_ops *ops) 284 { 285 int err; 286 287 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); 288 if (err < 0) 289 return err; 290 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); 291 if (err < 0) 292 return err; 293 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); 294 if (err < 0) 295 return err; 296 return 0; 297 } 298 299 int __net_init fib4_rules_init(struct net *net) 300 { 301 int err; 302 struct fib_rules_ops *ops; 303 304 ops = fib_rules_register(&fib4_rules_ops_template, net); 305 if (IS_ERR(ops)) 306 return PTR_ERR(ops); 307 308 err = fib_default_rules_init(ops); 309 if (err < 0) 310 goto fail; 311 net->ipv4.rules_ops = ops; 312 net->ipv4.fib_has_custom_rules = false; 313 return 0; 314 315 fail: 316 /* also cleans all rules already added */ 317 fib_rules_unregister(ops); 318 return err; 319 } 320 321 void __net_exit fib4_rules_exit(struct net *net) 322 { 323 fib_rules_unregister(net->ipv4.rules_ops); 324 } 325