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 18 #include <net/fib_rules.h> 19 #include <net/ipv6.h> 20 #include <net/addrconf.h> 21 #include <net/ip6_route.h> 22 #include <net/netlink.h> 23 24 struct fib6_rule 25 { 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 flowi *fl, 33 int flags, pol_lookup_t lookup) 34 { 35 struct fib_lookup_arg arg = { 36 .lookup_ptr = lookup, 37 }; 38 39 fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg); 40 if (arg.rule) 41 fib_rule_put(arg.rule); 42 43 if (arg.result) 44 return arg.result; 45 46 dst_hold(&net->ipv6.ip6_null_entry->u.dst); 47 return &net->ipv6.ip6_null_entry->u.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 rt6_info *rt = NULL; 54 struct fib6_table *table; 55 struct net *net = rule->fr_net; 56 pol_lookup_t lookup = arg->lookup_ptr; 57 58 switch (rule->action) { 59 case FR_ACT_TO_TBL: 60 break; 61 case FR_ACT_UNREACHABLE: 62 rt = net->ipv6.ip6_null_entry; 63 goto discard_pkt; 64 default: 65 case FR_ACT_BLACKHOLE: 66 rt = net->ipv6.ip6_blk_hole_entry; 67 goto discard_pkt; 68 case FR_ACT_PROHIBIT: 69 rt = net->ipv6.ip6_prohibit_entry; 70 goto discard_pkt; 71 } 72 73 table = fib6_get_table(net, rule->table); 74 if (table) 75 rt = lookup(net, table, flp, flags); 76 77 if (rt != net->ipv6.ip6_null_entry) { 78 struct fib6_rule *r = (struct fib6_rule *)rule; 79 80 /* 81 * If we need to find a source address for this traffic, 82 * we check the result if it meets requirement of the rule. 83 */ 84 if ((rule->flags & FIB_RULE_FIND_SADDR) && 85 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 86 struct in6_addr saddr; 87 88 if (ipv6_dev_get_saddr(net, 89 ip6_dst_idev(&rt->u.dst)->dev, 90 &flp->fl6_dst, 91 rt6_flags2srcprefs(flags), 92 &saddr)) 93 goto again; 94 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 95 r->src.plen)) 96 goto again; 97 ipv6_addr_copy(&flp->fl6_src, &saddr); 98 } 99 goto out; 100 } 101 again: 102 dst_release(&rt->u.dst); 103 rt = NULL; 104 goto out; 105 106 discard_pkt: 107 dst_hold(&rt->u.dst); 108 out: 109 arg->result = rt; 110 return rt == NULL ? -EAGAIN : 0; 111 } 112 113 114 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 115 { 116 struct fib6_rule *r = (struct fib6_rule *) rule; 117 118 if (r->dst.plen && 119 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 120 return 0; 121 122 /* 123 * If FIB_RULE_FIND_SADDR is set and we do not have a 124 * source address for the traffic, we defer check for 125 * source address. 126 */ 127 if (r->src.plen) { 128 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 129 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 130 r->src.plen)) 131 return 0; 132 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 133 return 0; 134 } 135 136 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 137 return 0; 138 139 return 1; 140 } 141 142 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 143 FRA_GENERIC_POLICY, 144 }; 145 146 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 147 struct fib_rule_hdr *frh, 148 struct nlattr **tb) 149 { 150 int err = -EINVAL; 151 struct net *net = sock_net(skb->sk); 152 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 153 154 if (rule->action == FR_ACT_TO_TBL) { 155 if (rule->table == RT6_TABLE_UNSPEC) 156 goto errout; 157 158 if (fib6_new_table(net, rule->table) == NULL) { 159 err = -ENOBUFS; 160 goto errout; 161 } 162 } 163 164 if (frh->src_len) 165 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 166 sizeof(struct in6_addr)); 167 168 if (frh->dst_len) 169 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 170 sizeof(struct in6_addr)); 171 172 rule6->src.plen = frh->src_len; 173 rule6->dst.plen = frh->dst_len; 174 rule6->tclass = frh->tos; 175 176 err = 0; 177 errout: 178 return err; 179 } 180 181 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 182 struct nlattr **tb) 183 { 184 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 185 186 if (frh->src_len && (rule6->src.plen != frh->src_len)) 187 return 0; 188 189 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 190 return 0; 191 192 if (frh->tos && (rule6->tclass != frh->tos)) 193 return 0; 194 195 if (frh->src_len && 196 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 197 return 0; 198 199 if (frh->dst_len && 200 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 201 return 0; 202 203 return 1; 204 } 205 206 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 207 struct fib_rule_hdr *frh) 208 { 209 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 210 211 frh->dst_len = rule6->dst.plen; 212 frh->src_len = rule6->src.plen; 213 frh->tos = rule6->tclass; 214 215 if (rule6->dst.plen) 216 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 217 &rule6->dst.addr); 218 219 if (rule6->src.plen) 220 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 221 &rule6->src.addr); 222 223 return 0; 224 225 nla_put_failure: 226 return -ENOBUFS; 227 } 228 229 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 230 { 231 return 0x3FFF; 232 } 233 234 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 235 { 236 return nla_total_size(16) /* dst */ 237 + nla_total_size(16); /* src */ 238 } 239 240 static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = { 241 .family = AF_INET6, 242 .rule_size = sizeof(struct fib6_rule), 243 .addr_size = sizeof(struct in6_addr), 244 .action = fib6_rule_action, 245 .match = fib6_rule_match, 246 .configure = fib6_rule_configure, 247 .compare = fib6_rule_compare, 248 .fill = fib6_rule_fill, 249 .default_pref = fib6_rule_default_pref, 250 .nlmsg_payload = fib6_rule_nlmsg_payload, 251 .nlgroup = RTNLGRP_IPV6_RULE, 252 .policy = fib6_rule_policy, 253 .owner = THIS_MODULE, 254 .fro_net = &init_net, 255 }; 256 257 static int __net_init fib6_rules_net_init(struct net *net) 258 { 259 struct fib_rules_ops *ops; 260 int err = -ENOMEM; 261 262 ops = fib_rules_register(&fib6_rules_ops_template, net); 263 if (IS_ERR(ops)) 264 return PTR_ERR(ops); 265 net->ipv6.fib6_rules_ops = ops; 266 267 268 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, 269 RT6_TABLE_LOCAL, 0); 270 if (err) 271 goto out_fib6_rules_ops; 272 273 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 274 0x7FFE, RT6_TABLE_MAIN, 0); 275 if (err) 276 goto out_fib6_rules_ops; 277 278 out: 279 return err; 280 281 out_fib6_rules_ops: 282 fib_rules_unregister(ops); 283 goto out; 284 } 285 286 static void __net_exit fib6_rules_net_exit(struct net *net) 287 { 288 fib_rules_unregister(net->ipv6.fib6_rules_ops); 289 } 290 291 static struct pernet_operations fib6_rules_net_ops = { 292 .init = fib6_rules_net_init, 293 .exit = fib6_rules_net_exit, 294 }; 295 296 int __init fib6_rules_init(void) 297 { 298 return register_pernet_subsys(&fib6_rules_net_ops); 299 } 300 301 302 void fib6_rules_cleanup(void) 303 { 304 unregister_pernet_subsys(&fib6_rules_net_ops); 305 } 306