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 unsigned int srcprefs = 0; 88 89 if (flags & RT6_LOOKUP_F_SRCPREF_TMP) 90 srcprefs |= IPV6_PREFER_SRC_TMP; 91 if (flags & RT6_LOOKUP_F_SRCPREF_PUBLIC) 92 srcprefs |= IPV6_PREFER_SRC_PUBLIC; 93 if (flags & RT6_LOOKUP_F_SRCPREF_COA) 94 srcprefs |= IPV6_PREFER_SRC_COA; 95 96 if (ipv6_dev_get_saddr(net, 97 ip6_dst_idev(&rt->u.dst)->dev, 98 &flp->fl6_dst, srcprefs, 99 &saddr)) 100 goto again; 101 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 102 r->src.plen)) 103 goto again; 104 ipv6_addr_copy(&flp->fl6_src, &saddr); 105 } 106 goto out; 107 } 108 again: 109 dst_release(&rt->u.dst); 110 rt = NULL; 111 goto out; 112 113 discard_pkt: 114 dst_hold(&rt->u.dst); 115 out: 116 arg->result = rt; 117 return rt == NULL ? -EAGAIN : 0; 118 } 119 120 121 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 122 { 123 struct fib6_rule *r = (struct fib6_rule *) rule; 124 125 if (r->dst.plen && 126 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 127 return 0; 128 129 /* 130 * If FIB_RULE_FIND_SADDR is set and we do not have a 131 * source address for the traffic, we defer check for 132 * source address. 133 */ 134 if (r->src.plen) { 135 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 136 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 137 r->src.plen)) 138 return 0; 139 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 140 return 0; 141 } 142 143 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 144 return 0; 145 146 return 1; 147 } 148 149 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 150 FRA_GENERIC_POLICY, 151 }; 152 153 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 154 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 155 struct nlattr **tb) 156 { 157 int err = -EINVAL; 158 struct net *net = sock_net(skb->sk); 159 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 160 161 if (rule->action == FR_ACT_TO_TBL) { 162 if (rule->table == RT6_TABLE_UNSPEC) 163 goto errout; 164 165 if (fib6_new_table(net, rule->table) == NULL) { 166 err = -ENOBUFS; 167 goto errout; 168 } 169 } 170 171 if (frh->src_len) 172 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 173 sizeof(struct in6_addr)); 174 175 if (frh->dst_len) 176 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 177 sizeof(struct in6_addr)); 178 179 rule6->src.plen = frh->src_len; 180 rule6->dst.plen = frh->dst_len; 181 rule6->tclass = frh->tos; 182 183 err = 0; 184 errout: 185 return err; 186 } 187 188 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 189 struct nlattr **tb) 190 { 191 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 192 193 if (frh->src_len && (rule6->src.plen != frh->src_len)) 194 return 0; 195 196 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 197 return 0; 198 199 if (frh->tos && (rule6->tclass != frh->tos)) 200 return 0; 201 202 if (frh->src_len && 203 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 204 return 0; 205 206 if (frh->dst_len && 207 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 208 return 0; 209 210 return 1; 211 } 212 213 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 214 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 215 { 216 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 217 218 frh->family = AF_INET6; 219 frh->dst_len = rule6->dst.plen; 220 frh->src_len = rule6->src.plen; 221 frh->tos = rule6->tclass; 222 223 if (rule6->dst.plen) 224 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 225 &rule6->dst.addr); 226 227 if (rule6->src.plen) 228 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 229 &rule6->src.addr); 230 231 return 0; 232 233 nla_put_failure: 234 return -ENOBUFS; 235 } 236 237 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 238 { 239 return 0x3FFF; 240 } 241 242 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 243 { 244 return nla_total_size(16) /* dst */ 245 + nla_total_size(16); /* src */ 246 } 247 248 static struct fib_rules_ops fib6_rules_ops_template = { 249 .family = AF_INET6, 250 .rule_size = sizeof(struct fib6_rule), 251 .addr_size = sizeof(struct in6_addr), 252 .action = fib6_rule_action, 253 .match = fib6_rule_match, 254 .configure = fib6_rule_configure, 255 .compare = fib6_rule_compare, 256 .fill = fib6_rule_fill, 257 .default_pref = fib6_rule_default_pref, 258 .nlmsg_payload = fib6_rule_nlmsg_payload, 259 .nlgroup = RTNLGRP_IPV6_RULE, 260 .policy = fib6_rule_policy, 261 .owner = THIS_MODULE, 262 .fro_net = &init_net, 263 }; 264 265 static int fib6_rules_net_init(struct net *net) 266 { 267 int err = -ENOMEM; 268 269 net->ipv6.fib6_rules_ops = kmemdup(&fib6_rules_ops_template, 270 sizeof(*net->ipv6.fib6_rules_ops), 271 GFP_KERNEL); 272 if (!net->ipv6.fib6_rules_ops) 273 goto out; 274 275 net->ipv6.fib6_rules_ops->fro_net = net; 276 INIT_LIST_HEAD(&net->ipv6.fib6_rules_ops->rules_list); 277 278 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, 279 RT6_TABLE_LOCAL, FIB_RULE_PERMANENT); 280 if (err) 281 goto out_fib6_rules_ops; 282 283 err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 284 0x7FFE, RT6_TABLE_MAIN, 0); 285 if (err) 286 goto out_fib6_default_rule_add; 287 288 err = fib_rules_register(net->ipv6.fib6_rules_ops); 289 if (err) 290 goto out_fib6_default_rule_add; 291 out: 292 return err; 293 294 out_fib6_default_rule_add: 295 fib_rules_cleanup_ops(net->ipv6.fib6_rules_ops); 296 out_fib6_rules_ops: 297 kfree(net->ipv6.fib6_rules_ops); 298 goto out; 299 } 300 301 static void fib6_rules_net_exit(struct net *net) 302 { 303 fib_rules_unregister(net->ipv6.fib6_rules_ops); 304 kfree(net->ipv6.fib6_rules_ops); 305 } 306 307 static struct pernet_operations fib6_rules_net_ops = { 308 .init = fib6_rules_net_init, 309 .exit = fib6_rules_net_exit, 310 }; 311 312 int __init fib6_rules_init(void) 313 { 314 return register_pernet_subsys(&fib6_rules_net_ops); 315 } 316 317 318 void fib6_rules_cleanup(void) 319 { 320 unregister_pernet_subsys(&fib6_rules_net_ops); 321 } 322