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 .flags = FIB_LOOKUP_NOREF, 38 }; 39 40 fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg); 41 42 if (arg.result) 43 return arg.result; 44 45 dst_hold(&net->ipv6.ip6_null_entry->dst); 46 return &net->ipv6.ip6_null_entry->dst; 47 } 48 49 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 50 int flags, struct fib_lookup_arg *arg) 51 { 52 struct rt6_info *rt = NULL; 53 struct fib6_table *table; 54 struct net *net = rule->fr_net; 55 pol_lookup_t lookup = arg->lookup_ptr; 56 57 switch (rule->action) { 58 case FR_ACT_TO_TBL: 59 break; 60 case FR_ACT_UNREACHABLE: 61 rt = net->ipv6.ip6_null_entry; 62 goto discard_pkt; 63 default: 64 case FR_ACT_BLACKHOLE: 65 rt = net->ipv6.ip6_blk_hole_entry; 66 goto discard_pkt; 67 case FR_ACT_PROHIBIT: 68 rt = net->ipv6.ip6_prohibit_entry; 69 goto discard_pkt; 70 } 71 72 table = fib6_get_table(net, rule->table); 73 if (table) 74 rt = lookup(net, table, flp, flags); 75 76 if (rt != net->ipv6.ip6_null_entry) { 77 struct fib6_rule *r = (struct fib6_rule *)rule; 78 79 /* 80 * If we need to find a source address for this traffic, 81 * we check the result if it meets requirement of the rule. 82 */ 83 if ((rule->flags & FIB_RULE_FIND_SADDR) && 84 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 85 struct in6_addr saddr; 86 87 if (ipv6_dev_get_saddr(net, 88 ip6_dst_idev(&rt->dst)->dev, 89 &flp->fl6_dst, 90 rt6_flags2srcprefs(flags), 91 &saddr)) 92 goto again; 93 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 94 r->src.plen)) 95 goto again; 96 ipv6_addr_copy(&flp->fl6_src, &saddr); 97 } 98 goto out; 99 } 100 again: 101 dst_release(&rt->dst); 102 rt = NULL; 103 goto out; 104 105 discard_pkt: 106 dst_hold(&rt->dst); 107 out: 108 arg->result = rt; 109 return rt == NULL ? -EAGAIN : 0; 110 } 111 112 113 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 114 { 115 struct fib6_rule *r = (struct fib6_rule *) rule; 116 117 if (r->dst.plen && 118 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 119 return 0; 120 121 /* 122 * If FIB_RULE_FIND_SADDR is set and we do not have a 123 * source address for the traffic, we defer check for 124 * source address. 125 */ 126 if (r->src.plen) { 127 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 128 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 129 r->src.plen)) 130 return 0; 131 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 132 return 0; 133 } 134 135 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 136 return 0; 137 138 return 1; 139 } 140 141 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 142 FRA_GENERIC_POLICY, 143 }; 144 145 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 146 struct fib_rule_hdr *frh, 147 struct nlattr **tb) 148 { 149 int err = -EINVAL; 150 struct net *net = sock_net(skb->sk); 151 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 152 153 if (rule->action == FR_ACT_TO_TBL) { 154 if (rule->table == RT6_TABLE_UNSPEC) 155 goto errout; 156 157 if (fib6_new_table(net, rule->table) == NULL) { 158 err = -ENOBUFS; 159 goto errout; 160 } 161 } 162 163 if (frh->src_len) 164 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 165 sizeof(struct in6_addr)); 166 167 if (frh->dst_len) 168 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 169 sizeof(struct in6_addr)); 170 171 rule6->src.plen = frh->src_len; 172 rule6->dst.plen = frh->dst_len; 173 rule6->tclass = frh->tos; 174 175 err = 0; 176 errout: 177 return err; 178 } 179 180 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 181 struct nlattr **tb) 182 { 183 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 184 185 if (frh->src_len && (rule6->src.plen != frh->src_len)) 186 return 0; 187 188 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 189 return 0; 190 191 if (frh->tos && (rule6->tclass != frh->tos)) 192 return 0; 193 194 if (frh->src_len && 195 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 196 return 0; 197 198 if (frh->dst_len && 199 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 200 return 0; 201 202 return 1; 203 } 204 205 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 206 struct fib_rule_hdr *frh) 207 { 208 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 209 210 frh->dst_len = rule6->dst.plen; 211 frh->src_len = rule6->src.plen; 212 frh->tos = rule6->tclass; 213 214 if (rule6->dst.plen) 215 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 216 &rule6->dst.addr); 217 218 if (rule6->src.plen) 219 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 220 &rule6->src.addr); 221 222 return 0; 223 224 nla_put_failure: 225 return -ENOBUFS; 226 } 227 228 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 229 { 230 return 0x3FFF; 231 } 232 233 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 234 { 235 return nla_total_size(16) /* dst */ 236 + nla_total_size(16); /* src */ 237 } 238 239 static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = { 240 .family = AF_INET6, 241 .rule_size = sizeof(struct fib6_rule), 242 .addr_size = sizeof(struct in6_addr), 243 .action = fib6_rule_action, 244 .match = fib6_rule_match, 245 .configure = fib6_rule_configure, 246 .compare = fib6_rule_compare, 247 .fill = fib6_rule_fill, 248 .default_pref = fib6_rule_default_pref, 249 .nlmsg_payload = fib6_rule_nlmsg_payload, 250 .nlgroup = RTNLGRP_IPV6_RULE, 251 .policy = fib6_rule_policy, 252 .owner = THIS_MODULE, 253 .fro_net = &init_net, 254 }; 255 256 static int __net_init fib6_rules_net_init(struct net *net) 257 { 258 struct fib_rules_ops *ops; 259 int err = -ENOMEM; 260 261 ops = fib_rules_register(&fib6_rules_ops_template, net); 262 if (IS_ERR(ops)) 263 return PTR_ERR(ops); 264 net->ipv6.fib6_rules_ops = ops; 265 266 267 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, 268 RT6_TABLE_LOCAL, 0); 269 if (err) 270 goto out_fib6_rules_ops; 271 272 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 273 0x7FFE, RT6_TABLE_MAIN, 0); 274 if (err) 275 goto out_fib6_rules_ops; 276 277 out: 278 return err; 279 280 out_fib6_rules_ops: 281 fib_rules_unregister(ops); 282 goto out; 283 } 284 285 static void __net_exit fib6_rules_net_exit(struct net *net) 286 { 287 fib_rules_unregister(net->ipv6.fib6_rules_ops); 288 } 289 290 static struct pernet_operations fib6_rules_net_ops = { 291 .init = fib6_rules_net_init, 292 .exit = fib6_rules_net_exit, 293 }; 294 295 int __init fib6_rules_init(void) 296 { 297 return register_pernet_subsys(&fib6_rules_net_ops); 298 } 299 300 301 void fib6_rules_cleanup(void) 302 { 303 unregister_pernet_subsys(&fib6_rules_net_ops); 304 } 305