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 71 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 72 int flags, struct fib_lookup_arg *arg) 73 { 74 int err = -EAGAIN; 75 struct fib_table *tbl; 76 77 switch (rule->action) { 78 case FR_ACT_TO_TBL: 79 break; 80 81 case FR_ACT_UNREACHABLE: 82 err = -ENETUNREACH; 83 goto errout; 84 85 case FR_ACT_PROHIBIT: 86 err = -EACCES; 87 goto errout; 88 89 case FR_ACT_BLACKHOLE: 90 default: 91 err = -EINVAL; 92 goto errout; 93 } 94 95 tbl = fib_get_table(rule->fr_net, rule->table); 96 if (!tbl) 97 goto errout; 98 99 err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags); 100 if (err > 0) 101 err = -EAGAIN; 102 errout: 103 return err; 104 } 105 106 107 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 108 { 109 struct fib4_rule *r = (struct fib4_rule *) rule; 110 struct flowi4 *fl4 = &fl->u.ip4; 111 __be32 daddr = fl4->daddr; 112 __be32 saddr = fl4->saddr; 113 114 if (((saddr ^ r->src) & r->srcmask) || 115 ((daddr ^ r->dst) & r->dstmask)) 116 return 0; 117 118 if (r->tos && (r->tos != fl4->flowi4_tos)) 119 return 0; 120 121 return 1; 122 } 123 124 static struct fib_table *fib_empty_table(struct net *net) 125 { 126 u32 id; 127 128 for (id = 1; id <= RT_TABLE_MAX; id++) 129 if (fib_get_table(net, id) == NULL) 130 return fib_new_table(net, id); 131 return NULL; 132 } 133 134 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 135 FRA_GENERIC_POLICY, 136 [FRA_FLOW] = { .type = NLA_U32 }, 137 }; 138 139 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 140 struct fib_rule_hdr *frh, 141 struct nlattr **tb) 142 { 143 struct net *net = sock_net(skb->sk); 144 int err = -EINVAL; 145 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 146 147 if (frh->tos & ~IPTOS_TOS_MASK) 148 goto errout; 149 150 if (rule->table == RT_TABLE_UNSPEC) { 151 if (rule->action == FR_ACT_TO_TBL) { 152 struct fib_table *table; 153 154 table = fib_empty_table(net); 155 if (table == NULL) { 156 err = -ENOBUFS; 157 goto errout; 158 } 159 160 rule->table = table->tb_id; 161 } 162 } 163 164 if (frh->src_len) 165 rule4->src = nla_get_be32(tb[FRA_SRC]); 166 167 if (frh->dst_len) 168 rule4->dst = nla_get_be32(tb[FRA_DST]); 169 170 #ifdef CONFIG_IP_ROUTE_CLASSID 171 if (tb[FRA_FLOW]) 172 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 173 #endif 174 175 rule4->src_len = frh->src_len; 176 rule4->srcmask = inet_make_mask(rule4->src_len); 177 rule4->dst_len = frh->dst_len; 178 rule4->dstmask = inet_make_mask(rule4->dst_len); 179 rule4->tos = frh->tos; 180 181 err = 0; 182 errout: 183 return err; 184 } 185 186 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 187 struct nlattr **tb) 188 { 189 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 190 191 if (frh->src_len && (rule4->src_len != frh->src_len)) 192 return 0; 193 194 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 195 return 0; 196 197 if (frh->tos && (rule4->tos != frh->tos)) 198 return 0; 199 200 #ifdef CONFIG_IP_ROUTE_CLASSID 201 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 202 return 0; 203 #endif 204 205 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 206 return 0; 207 208 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 209 return 0; 210 211 return 1; 212 } 213 214 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 215 struct fib_rule_hdr *frh) 216 { 217 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 218 219 frh->dst_len = rule4->dst_len; 220 frh->src_len = rule4->src_len; 221 frh->tos = rule4->tos; 222 223 if (rule4->dst_len) 224 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 225 226 if (rule4->src_len) 227 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 228 229 #ifdef CONFIG_IP_ROUTE_CLASSID 230 if (rule4->tclassid) 231 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 232 #endif 233 return 0; 234 235 nla_put_failure: 236 return -ENOBUFS; 237 } 238 239 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 240 { 241 return nla_total_size(4) /* dst */ 242 + nla_total_size(4) /* src */ 243 + nla_total_size(4); /* flow */ 244 } 245 246 static void fib4_rule_flush_cache(struct fib_rules_ops *ops) 247 { 248 rt_cache_flush(ops->fro_net, -1); 249 } 250 251 static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = { 252 .family = AF_INET, 253 .rule_size = sizeof(struct fib4_rule), 254 .addr_size = sizeof(u32), 255 .action = fib4_rule_action, 256 .match = fib4_rule_match, 257 .configure = fib4_rule_configure, 258 .compare = fib4_rule_compare, 259 .fill = fib4_rule_fill, 260 .default_pref = fib_default_rule_pref, 261 .nlmsg_payload = fib4_rule_nlmsg_payload, 262 .flush_cache = fib4_rule_flush_cache, 263 .nlgroup = RTNLGRP_IPV4_RULE, 264 .policy = fib4_rule_policy, 265 .owner = THIS_MODULE, 266 }; 267 268 static int fib_default_rules_init(struct fib_rules_ops *ops) 269 { 270 int err; 271 272 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); 273 if (err < 0) 274 return err; 275 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); 276 if (err < 0) 277 return err; 278 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); 279 if (err < 0) 280 return err; 281 return 0; 282 } 283 284 int __net_init fib4_rules_init(struct net *net) 285 { 286 int err; 287 struct fib_rules_ops *ops; 288 289 ops = fib_rules_register(&fib4_rules_ops_template, net); 290 if (IS_ERR(ops)) 291 return PTR_ERR(ops); 292 293 err = fib_default_rules_init(ops); 294 if (err < 0) 295 goto fail; 296 net->ipv4.rules_ops = ops; 297 return 0; 298 299 fail: 300 /* also cleans all rules already added */ 301 fib_rules_unregister(ops); 302 return err; 303 } 304 305 void __net_exit fib4_rules_exit(struct net *net) 306 { 307 fib_rules_unregister(net->ipv4.rules_ops); 308 } 309