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 fib_rules_lookup(net->ipv6.fib6_rules_ops, 41 flowi6_to_flowi(fl6), flags, &arg); 42 43 if (arg.result) 44 return arg.result; 45 46 dst_hold(&net->ipv6.ip6_null_entry->dst); 47 return &net->ipv6.ip6_null_entry->dst; 48 } 49 50 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 51 int flags, struct fib_lookup_arg *arg) 52 { 53 struct flowi6 *flp6 = &flp->u.ip6; 54 struct rt6_info *rt = NULL; 55 struct fib6_table *table; 56 struct net *net = rule->fr_net; 57 pol_lookup_t lookup = arg->lookup_ptr; 58 int err = 0; 59 60 switch (rule->action) { 61 case FR_ACT_TO_TBL: 62 break; 63 case FR_ACT_UNREACHABLE: 64 err = -ENETUNREACH; 65 rt = net->ipv6.ip6_null_entry; 66 goto discard_pkt; 67 default: 68 case FR_ACT_BLACKHOLE: 69 err = -EINVAL; 70 rt = net->ipv6.ip6_blk_hole_entry; 71 goto discard_pkt; 72 case FR_ACT_PROHIBIT: 73 err = -EACCES; 74 rt = net->ipv6.ip6_prohibit_entry; 75 goto discard_pkt; 76 } 77 78 table = fib6_get_table(net, rule->table); 79 if (!table) { 80 err = -EAGAIN; 81 goto out; 82 } 83 84 rt = lookup(net, table, flp6, flags); 85 if (rt != net->ipv6.ip6_null_entry) { 86 struct fib6_rule *r = (struct fib6_rule *)rule; 87 88 /* 89 * If we need to find a source address for this traffic, 90 * we check the result if it meets requirement of the rule. 91 */ 92 if ((rule->flags & FIB_RULE_FIND_SADDR) && 93 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 94 struct in6_addr saddr; 95 96 if (ipv6_dev_get_saddr(net, 97 ip6_dst_idev(&rt->dst)->dev, 98 &flp6->daddr, 99 rt6_flags2srcprefs(flags), 100 &saddr)) 101 goto again; 102 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 103 r->src.plen)) 104 goto again; 105 flp6->saddr = saddr; 106 } 107 err = rt->dst.error; 108 goto out; 109 } 110 again: 111 ip6_rt_put(rt); 112 err = -EAGAIN; 113 rt = NULL; 114 goto out; 115 116 discard_pkt: 117 dst_hold(&rt->dst); 118 out: 119 arg->result = rt; 120 return err; 121 } 122 123 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 124 { 125 struct rt6_info *rt = (struct rt6_info *) arg->result; 126 struct net_device *dev = NULL; 127 128 if (rt->rt6i_idev) 129 dev = rt->rt6i_idev->dev; 130 131 /* do not accept result if the route does 132 * not meet the required prefix length 133 */ 134 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 135 goto suppress_route; 136 137 /* do not accept result if the route uses a device 138 * belonging to a forbidden interface group 139 */ 140 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 141 goto suppress_route; 142 143 return false; 144 145 suppress_route: 146 ip6_rt_put(rt); 147 return true; 148 } 149 150 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 151 { 152 struct fib6_rule *r = (struct fib6_rule *) rule; 153 struct flowi6 *fl6 = &fl->u.ip6; 154 155 if (r->dst.plen && 156 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 157 return 0; 158 159 /* 160 * If FIB_RULE_FIND_SADDR is set and we do not have a 161 * source address for the traffic, we defer check for 162 * source address. 163 */ 164 if (r->src.plen) { 165 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 166 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 167 r->src.plen)) 168 return 0; 169 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 170 return 0; 171 } 172 173 if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel)) 174 return 0; 175 176 return 1; 177 } 178 179 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 180 FRA_GENERIC_POLICY, 181 }; 182 183 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 184 struct fib_rule_hdr *frh, 185 struct nlattr **tb) 186 { 187 int err = -EINVAL; 188 struct net *net = sock_net(skb->sk); 189 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 190 191 if (rule->action == FR_ACT_TO_TBL) { 192 if (rule->table == RT6_TABLE_UNSPEC) 193 goto errout; 194 195 if (fib6_new_table(net, rule->table) == NULL) { 196 err = -ENOBUFS; 197 goto errout; 198 } 199 } 200 201 if (frh->src_len) 202 rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]); 203 204 if (frh->dst_len) 205 rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]); 206 207 rule6->src.plen = frh->src_len; 208 rule6->dst.plen = frh->dst_len; 209 rule6->tclass = frh->tos; 210 211 err = 0; 212 errout: 213 return err; 214 } 215 216 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 217 struct nlattr **tb) 218 { 219 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 220 221 if (frh->src_len && (rule6->src.plen != frh->src_len)) 222 return 0; 223 224 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 225 return 0; 226 227 if (frh->tos && (rule6->tclass != frh->tos)) 228 return 0; 229 230 if (frh->src_len && 231 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 232 return 0; 233 234 if (frh->dst_len && 235 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 236 return 0; 237 238 return 1; 239 } 240 241 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 242 struct fib_rule_hdr *frh) 243 { 244 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 245 246 frh->dst_len = rule6->dst.plen; 247 frh->src_len = rule6->src.plen; 248 frh->tos = rule6->tclass; 249 250 if ((rule6->dst.plen && 251 nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) || 252 (rule6->src.plen && 253 nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr))) 254 goto nla_put_failure; 255 return 0; 256 257 nla_put_failure: 258 return -ENOBUFS; 259 } 260 261 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 262 { 263 return 0x3FFF; 264 } 265 266 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 267 { 268 return nla_total_size(16) /* dst */ 269 + nla_total_size(16); /* src */ 270 } 271 272 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 273 .family = AF_INET6, 274 .rule_size = sizeof(struct fib6_rule), 275 .addr_size = sizeof(struct in6_addr), 276 .action = fib6_rule_action, 277 .match = fib6_rule_match, 278 .suppress = fib6_rule_suppress, 279 .configure = fib6_rule_configure, 280 .compare = fib6_rule_compare, 281 .fill = fib6_rule_fill, 282 .default_pref = fib6_rule_default_pref, 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