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 59 switch (rule->action) { 60 case FR_ACT_TO_TBL: 61 break; 62 case FR_ACT_UNREACHABLE: 63 rt = net->ipv6.ip6_null_entry; 64 goto discard_pkt; 65 default: 66 case FR_ACT_BLACKHOLE: 67 rt = net->ipv6.ip6_blk_hole_entry; 68 goto discard_pkt; 69 case FR_ACT_PROHIBIT: 70 rt = net->ipv6.ip6_prohibit_entry; 71 goto discard_pkt; 72 } 73 74 table = fib6_get_table(net, rule->table); 75 if (table) 76 rt = lookup(net, table, flp6, flags); 77 78 if (rt != net->ipv6.ip6_null_entry) { 79 struct fib6_rule *r = (struct fib6_rule *)rule; 80 81 /* 82 * If we need to find a source address for this traffic, 83 * we check the result if it meets requirement of the rule. 84 */ 85 if ((rule->flags & FIB_RULE_FIND_SADDR) && 86 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 87 struct in6_addr saddr; 88 89 if (ipv6_dev_get_saddr(net, 90 ip6_dst_idev(&rt->dst)->dev, 91 &flp6->daddr, 92 rt6_flags2srcprefs(flags), 93 &saddr)) 94 goto again; 95 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 96 r->src.plen)) 97 goto again; 98 flp6->saddr = saddr; 99 } 100 goto out; 101 } 102 again: 103 ip6_rt_put(rt); 104 rt = NULL; 105 goto out; 106 107 discard_pkt: 108 dst_hold(&rt->dst); 109 out: 110 arg->result = rt; 111 return rt == NULL ? -EAGAIN : 0; 112 } 113 114 115 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 116 { 117 struct fib6_rule *r = (struct fib6_rule *) rule; 118 struct flowi6 *fl6 = &fl->u.ip6; 119 120 if (r->dst.plen && 121 !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) 122 return 0; 123 124 /* 125 * If FIB_RULE_FIND_SADDR is set and we do not have a 126 * source address for the traffic, we defer check for 127 * source address. 128 */ 129 if (r->src.plen) { 130 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 131 if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, 132 r->src.plen)) 133 return 0; 134 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 135 return 0; 136 } 137 138 if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff)) 139 return 0; 140 141 return 1; 142 } 143 144 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 145 FRA_GENERIC_POLICY, 146 }; 147 148 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 149 struct fib_rule_hdr *frh, 150 struct nlattr **tb) 151 { 152 int err = -EINVAL; 153 struct net *net = sock_net(skb->sk); 154 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 155 156 if (rule->action == FR_ACT_TO_TBL) { 157 if (rule->table == RT6_TABLE_UNSPEC) 158 goto errout; 159 160 if (fib6_new_table(net, rule->table) == NULL) { 161 err = -ENOBUFS; 162 goto errout; 163 } 164 } 165 166 if (frh->src_len) 167 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 168 sizeof(struct in6_addr)); 169 170 if (frh->dst_len) 171 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 172 sizeof(struct in6_addr)); 173 174 rule6->src.plen = frh->src_len; 175 rule6->dst.plen = frh->dst_len; 176 rule6->tclass = frh->tos; 177 178 err = 0; 179 errout: 180 return err; 181 } 182 183 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 184 struct nlattr **tb) 185 { 186 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 187 188 if (frh->src_len && (rule6->src.plen != frh->src_len)) 189 return 0; 190 191 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 192 return 0; 193 194 if (frh->tos && (rule6->tclass != frh->tos)) 195 return 0; 196 197 if (frh->src_len && 198 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 199 return 0; 200 201 if (frh->dst_len && 202 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 203 return 0; 204 205 return 1; 206 } 207 208 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 209 struct fib_rule_hdr *frh) 210 { 211 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 212 213 frh->dst_len = rule6->dst.plen; 214 frh->src_len = rule6->src.plen; 215 frh->tos = rule6->tclass; 216 217 if ((rule6->dst.plen && 218 nla_put(skb, FRA_DST, sizeof(struct in6_addr), 219 &rule6->dst.addr)) || 220 (rule6->src.plen && 221 nla_put(skb, FRA_SRC, sizeof(struct in6_addr), 222 &rule6->src.addr))) 223 goto nla_put_failure; 224 return 0; 225 226 nla_put_failure: 227 return -ENOBUFS; 228 } 229 230 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 231 { 232 return 0x3FFF; 233 } 234 235 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 236 { 237 return nla_total_size(16) /* dst */ 238 + nla_total_size(16); /* src */ 239 } 240 241 static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { 242 .family = AF_INET6, 243 .rule_size = sizeof(struct fib6_rule), 244 .addr_size = sizeof(struct in6_addr), 245 .action = fib6_rule_action, 246 .match = fib6_rule_match, 247 .configure = fib6_rule_configure, 248 .compare = fib6_rule_compare, 249 .fill = fib6_rule_fill, 250 .default_pref = fib6_rule_default_pref, 251 .nlmsg_payload = fib6_rule_nlmsg_payload, 252 .nlgroup = RTNLGRP_IPV6_RULE, 253 .policy = fib6_rule_policy, 254 .owner = THIS_MODULE, 255 .fro_net = &init_net, 256 }; 257 258 static int __net_init fib6_rules_net_init(struct net *net) 259 { 260 struct fib_rules_ops *ops; 261 int err = -ENOMEM; 262 263 ops = fib_rules_register(&fib6_rules_ops_template, net); 264 if (IS_ERR(ops)) 265 return PTR_ERR(ops); 266 net->ipv6.fib6_rules_ops = ops; 267 268 269 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, 270 RT6_TABLE_LOCAL, 0); 271 if (err) 272 goto out_fib6_rules_ops; 273 274 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 275 0x7FFE, RT6_TABLE_MAIN, 0); 276 if (err) 277 goto out_fib6_rules_ops; 278 279 out: 280 return err; 281 282 out_fib6_rules_ops: 283 fib_rules_unregister(ops); 284 goto out; 285 } 286 287 static void __net_exit fib6_rules_net_exit(struct net *net) 288 { 289 fib_rules_unregister(net->ipv6.fib6_rules_ops); 290 } 291 292 static struct pernet_operations fib6_rules_net_ops = { 293 .init = fib6_rules_net_init, 294 .exit = fib6_rules_net_exit, 295 }; 296 297 int __init fib6_rules_init(void) 298 { 299 return register_pernet_subsys(&fib6_rules_net_ops); 300 } 301 302 303 void fib6_rules_cleanup(void) 304 { 305 unregister_pernet_subsys(&fib6_rules_net_ops); 306 } 307