1 /* 2 * net/ipv6/fib6_rules.c IPv6 Routing Policy Rules 3 * 4 * Copyright (C)2003-2006 Helsinki University of Technology 5 * Copyright (C)2003-2006 USAGI/WIDE Project 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation, version 2. 10 * 11 * Authors 12 * Thomas Graf <tgraf@suug.ch> 13 * Ville Nuorvala <vnuorval@tcs.hut.fi> 14 */ 15 16 #include <linux/netdevice.h> 17 #include <linux/export.h> 18 19 #include <net/fib_rules.h> 20 #include <net/ipv6.h> 21 #include <net/addrconf.h> 22 #include <net/ip6_route.h> 23 #include <net/netlink.h> 24 25 struct fib6_rule { 26 struct fib_rule common; 27 struct rt6key src; 28 struct rt6key dst; 29 u8 tclass; 30 }; 31 32 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6, 33 int flags, pol_lookup_t lookup) 34 { 35 struct fib_lookup_arg arg = { 36 .lookup_ptr = lookup, 37 .flags = FIB_LOOKUP_NOREF, 38 }; 39 40 /* update flow if oif or iif point to device enslaved to l3mdev */ 41 l3mdev_update_flow(net, flowi6_to_flowi(fl6)); 42 43 fib_rules_lookup(net->ipv6.fib6_rules_ops, 44 flowi6_to_flowi(fl6), flags, &arg); 45 46 if (arg.result) 47 return arg.result; 48 49 dst_hold(&net->ipv6.ip6_null_entry->dst); 50 return &net->ipv6.ip6_null_entry->dst; 51 } 52 53 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 54 int flags, struct fib_lookup_arg *arg) 55 { 56 struct flowi6 *flp6 = &flp->u.ip6; 57 struct rt6_info *rt = NULL; 58 struct fib6_table *table; 59 struct net *net = rule->fr_net; 60 pol_lookup_t lookup = arg->lookup_ptr; 61 int err = 0; 62 u32 tb_id; 63 64 switch (rule->action) { 65 case FR_ACT_TO_TBL: 66 break; 67 case FR_ACT_UNREACHABLE: 68 err = -ENETUNREACH; 69 rt = net->ipv6.ip6_null_entry; 70 goto discard_pkt; 71 default: 72 case FR_ACT_BLACKHOLE: 73 err = -EINVAL; 74 rt = net->ipv6.ip6_blk_hole_entry; 75 goto discard_pkt; 76 case FR_ACT_PROHIBIT: 77 err = -EACCES; 78 rt = net->ipv6.ip6_prohibit_entry; 79 goto discard_pkt; 80 } 81 82 tb_id = fib_rule_get_table(rule, arg); 83 table = fib6_get_table(net, tb_id); 84 if (!table) { 85 err = -EAGAIN; 86 goto out; 87 } 88 89 rt = lookup(net, table, flp6, flags); 90 if (rt != net->ipv6.ip6_null_entry) { 91 struct fib6_rule *r = (struct fib6_rule *)rule; 92 93 /* 94 * If we need to find a source address for this traffic, 95 * we check the result if it meets requirement of the rule. 96 */ 97 if ((rule->flags & FIB_RULE_FIND_SADDR) && 98 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 99 struct in6_addr saddr; 100 101 if (ipv6_dev_get_saddr(net, 102 ip6_dst_idev(&rt->dst)->dev, 103 &flp6->daddr, 104 rt6_flags2srcprefs(flags), 105 &saddr)) 106 goto again; 107 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 108 r->src.plen)) 109 goto again; 110 flp6->saddr = saddr; 111 } 112 err = rt->dst.error; 113 if (err != -EAGAIN) 114 goto out; 115 } 116 again: 117 ip6_rt_put(rt); 118 err = -EAGAIN; 119 rt = NULL; 120 goto out; 121 122 discard_pkt: 123 dst_hold(&rt->dst); 124 out: 125 arg->result = rt; 126 return err; 127 } 128 129 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 130 { 131 struct rt6_info *rt = (struct rt6_info *) arg->result; 132 struct net_device *dev = NULL; 133 134 if (rt->rt6i_idev) 135 dev = rt->rt6i_idev->dev; 136 137 /* do not accept result if the route does 138 * not meet the required prefix length 139 */ 140 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 141 goto suppress_route; 142 143 /* do not accept result if the route uses a device 144 * belonging to a forbidden interface group 145 */ 146 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 147 goto suppress_route; 148 149 return false; 150 151 suppress_route: 152 ip6_rt_put(rt); 153 return true; 154 } 155 156 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 157 { 158 struct fib6_rule *r = (struct fib6_rule *) rule; 159 struct flowi6 *fl6 = &fl->u.ip6; 160 161 if (r->dst.plen && 162 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 163 return 0; 164 165 /* 166 * If FIB_RULE_FIND_SADDR is set and we do not have a 167 * source address for the traffic, we defer check for 168 * source address. 169 */ 170 if (r->src.plen) { 171 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 172 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 173 r->src.plen)) 174 return 0; 175 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 176 return 0; 177 } 178 179 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 180 return 0; 181 182 return 1; 183 } 184 185 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 186 FRA_GENERIC_POLICY, 187 }; 188 189 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 190 struct fib_rule_hdr *frh, 191 struct nlattr **tb) 192 { 193 int err = -EINVAL; 194 struct net *net = sock_net(skb->sk); 195 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 196 197 if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) { 198 if (rule->table == RT6_TABLE_UNSPEC) 199 goto errout; 200 201 if (fib6_new_table(net, rule->table) == NULL) { 202 err = -ENOBUFS; 203 goto errout; 204 } 205 } 206 207 if (frh->src_len) 208 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 209 210 if (frh->dst_len) 211 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 212 213 rule6->src.plen = frh->src_len; 214 rule6->dst.plen = frh->dst_len; 215 rule6->tclass = frh->tos; 216 217 err = 0; 218 errout: 219 return err; 220 } 221 222 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 223 struct nlattr **tb) 224 { 225 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 226 227 if (frh->src_len && (rule6->src.plen != frh->src_len)) 228 return 0; 229 230 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 231 return 0; 232 233 if (frh->tos && (rule6->tclass != frh->tos)) 234 return 0; 235 236 if (frh->src_len && 237 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 238 return 0; 239 240 if (frh->dst_len && 241 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 242 return 0; 243 244 return 1; 245 } 246 247 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 248 struct fib_rule_hdr *frh) 249 { 250 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 251 252 frh->dst_len = rule6->dst.plen; 253 frh->src_len = rule6->src.plen; 254 frh->tos = rule6->tclass; 255 256 if ((rule6->dst.plen && 257 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 258 (rule6->src.plen && 259 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 260 goto nla_put_failure; 261 return 0; 262 263 nla_put_failure: 264 return -ENOBUFS; 265 } 266 267 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 268 { 269 return nla_total_size(16) /* dst */ 270 + nla_total_size(16); /* src */ 271 } 272 273 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 274 .family = AF_INET6, 275 .rule_size = sizeof(struct fib6_rule), 276 .addr_size = sizeof(struct in6_addr), 277 .action = fib6_rule_action, 278 .match = fib6_rule_match, 279 .suppress = fib6_rule_suppress, 280 .configure = fib6_rule_configure, 281 .compare = fib6_rule_compare, 282 .fill = fib6_rule_fill, 283 .nlmsg_payload = fib6_rule_nlmsg_payload, 284 .nlgroup = RTNLGRP_IPV6_RULE, 285 .policy = fib6_rule_policy, 286 .owner = THIS_MODULE, 287 .fro_net = &init_net, 288 }; 289 290 static int __net_init fib6_rules_net_init(struct net *net) 291 { 292 struct fib_rules_ops *ops; 293 int err = -ENOMEM; 294 295 ops = fib_rules_register(&fib6_rules_ops_template, net); 296 if (IS_ERR(ops)) 297 return PTR_ERR(ops); 298 299 err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0); 300 if (err) 301 goto out_fib6_rules_ops; 302 303 err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0); 304 if (err) 305 goto out_fib6_rules_ops; 306 307 net->ipv6.fib6_rules_ops = ops; 308 out: 309 return err; 310 311 out_fib6_rules_ops: 312 fib_rules_unregister(ops); 313 goto out; 314 } 315 316 static void __net_exit fib6_rules_net_exit(struct net *net) 317 { 318 rtnl_lock(); 319 fib_rules_unregister(net->ipv6.fib6_rules_ops); 320 rtnl_unlock(); 321 } 322 323 static struct pernet_operations fib6_rules_net_ops = { 324 .init = fib6_rules_net_init, 325 .exit = fib6_rules_net_exit, 326 }; 327 328 int __init fib6_rules_init(void) 329 { 330 return register_pernet_subsys(&fib6_rules_net_ops); 331 } 332 333 334 void fib6_rules_cleanup(void) 335 { 336 unregister_pernet_subsys(&fib6_rules_net_ops); 337 } 338