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