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 goto out; 108 } 109 again: 110 ip6_rt_put(rt); 111 err = -EAGAIN; 112 rt = NULL; 113 goto out; 114 115 discard_pkt: 116 dst_hold(&rt->dst); 117 out: 118 arg->result = rt; 119 return err; 120 } 121 122 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) 123 { 124 struct rt6_info *rt = (struct rt6_info *) arg->result; 125 struct net_device *dev = rt->rt6i_idev->dev; 126 /* do not accept result if the route does 127 * not meet the required prefix length 128 */ 129 if (rt->rt6i_dst.plen <= rule->suppress_prefixlen) 130 goto suppress_route; 131 132 /* do not accept result if the route uses a device 133 * belonging to a forbidden interface group 134 */ 135 if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup) 136 goto suppress_route; 137 138 return false; 139 140 suppress_route: 141 ip6_rt_put(rt); 142 return true; 143 } 144 145 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 146 { 147 struct fib6_rule *r = (struct fib6_rule *) rule; 148 struct flowi6 *fl6 = &fl->u.ip6; 149 150 if (r->dst.plen && 151 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 152 return 0; 153 154 /* 155 * If FIB_RULE_FIND_SADDR is set and we do not have a 156 * source address for the traffic, we defer check for 157 * source address. 158 */ 159 if (r->src.plen) { 160 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 161 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 162 r->src.plen)) 163 return 0; 164 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 165 return 0; 166 } 167 168 if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff)) 169 return 0; 170 171 return 1; 172 } 173 174 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 175 FRA_GENERIC_POLICY, 176 }; 177 178 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 179 struct fib_rule_hdr *frh, 180 struct nlattr **tb) 181 { 182 int err = -EINVAL; 183 struct net *net = sock_net(skb->sk); 184 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 185 186 if (rule->action == FR_ACT_TO_TBL) { 187 if (rule->table == RT6_TABLE_UNSPEC) 188 goto errout; 189 190 if (fib6_new_table(net, rule->table) == NULL) { 191 err = -ENOBUFS; 192 goto errout; 193 } 194 } 195 196 if (frh->src_len) 197 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 198 sizeof(struct in6_addr)); 199 200 if (frh->dst_len) 201 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 202 sizeof(struct in6_addr)); 203 204 rule6->src.plen = frh->src_len; 205 rule6->dst.plen = frh->dst_len; 206 rule6->tclass = frh->tos; 207 208 err = 0; 209 errout: 210 return err; 211 } 212 213 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 214 struct nlattr **tb) 215 { 216 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 217 218 if (frh->src_len && (rule6->src.plen != frh->src_len)) 219 return 0; 220 221 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 222 return 0; 223 224 if (frh->tos && (rule6->tclass != frh->tos)) 225 return 0; 226 227 if (frh->src_len && 228 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 229 return 0; 230 231 if (frh->dst_len && 232 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 233 return 0; 234 235 return 1; 236 } 237 238 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 239 struct fib_rule_hdr *frh) 240 { 241 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 242 243 frh->dst_len = rule6->dst.plen; 244 frh->src_len = rule6->src.plen; 245 frh->tos = rule6->tclass; 246 247 if ((rule6->dst.plen && 248 nla_put(skb, FRA_DST, sizeof(struct in6_addr), 249 &rule6->dst.addr)) || 250 (rule6->src.plen && 251 nla_put(skb, FRA_SRC, sizeof(struct in6_addr), 252 &rule6->src.addr))) 253 goto nla_put_failure; 254 return 0; 255 256 nla_put_failure: 257 return -ENOBUFS; 258 } 259 260 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 261 { 262 return 0x3FFF; 263 } 264 265 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 266 { 267 return nla_total_size(16) /* dst */ 268 + nla_total_size(16); /* src */ 269 } 270 271 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 272 .family = AF_INET6, 273 .rule_size = sizeof(struct fib6_rule), 274 .addr_size = sizeof(struct in6_addr), 275 .action = fib6_rule_action, 276 .match = fib6_rule_match, 277 .suppress = fib6_rule_suppress, 278 .configure = fib6_rule_configure, 279 .compare = fib6_rule_compare, 280 .fill = fib6_rule_fill, 281 .default_pref = fib6_rule_default_pref, 282 .nlmsg_payload = fib6_rule_nlmsg_payload, 283 .nlgroup = RTNLGRP_IPV6_RULE, 284 .policy = fib6_rule_policy, 285 .owner = THIS_MODULE, 286 .fro_net = &init_net, 287 }; 288 289 static int __net_init fib6_rules_net_init(struct net *net) 290 { 291 struct fib_rules_ops *ops; 292 int err = -ENOMEM; 293 294 ops = fib_rules_register(&fib6_rules_ops_template, net); 295 if (IS_ERR(ops)) 296 return PTR_ERR(ops); 297 net->ipv6.fib6_rules_ops = ops; 298 299 300 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, 301 RT6_TABLE_LOCAL, 0); 302 if (err) 303 goto out_fib6_rules_ops; 304 305 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 306 0x7FFE, RT6_TABLE_MAIN, 0); 307 if (err) 308 goto out_fib6_rules_ops; 309 310 out: 311 return err; 312 313 out_fib6_rules_ops: 314 fib_rules_unregister(ops); 315 goto out; 316 } 317 318 static void __net_exit fib6_rules_net_exit(struct net *net) 319 { 320 fib_rules_unregister(net->ipv6.fib6_rules_ops); 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