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 static struct fib_rules_ops fib6_rules_ops; 33 34 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags, 35 pol_lookup_t lookup) 36 { 37 struct fib_lookup_arg arg = { 38 .lookup_ptr = lookup, 39 }; 40 41 fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg); 42 if (arg.rule) 43 fib_rule_put(arg.rule); 44 45 if (arg.result) 46 return arg.result; 47 48 dst_hold(&ip6_null_entry.u.dst); 49 return &ip6_null_entry.u.dst; 50 } 51 52 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 53 int flags, struct fib_lookup_arg *arg) 54 { 55 struct rt6_info *rt = NULL; 56 struct fib6_table *table; 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 = &ip6_null_entry; 64 goto discard_pkt; 65 default: 66 case FR_ACT_BLACKHOLE: 67 rt = &ip6_blk_hole_entry; 68 goto discard_pkt; 69 case FR_ACT_PROHIBIT: 70 rt = &ip6_prohibit_entry; 71 goto discard_pkt; 72 } 73 74 table = fib6_get_table(rule->table); 75 if (table) 76 rt = lookup(table, flp, flags); 77 78 if (rt != &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 if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst, 89 &saddr)) 90 goto again; 91 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 92 r->src.plen)) 93 goto again; 94 ipv6_addr_copy(&flp->fl6_src, &saddr); 95 } 96 goto out; 97 } 98 again: 99 dst_release(&rt->u.dst); 100 rt = NULL; 101 goto out; 102 103 discard_pkt: 104 dst_hold(&rt->u.dst); 105 out: 106 arg->result = rt; 107 return rt == NULL ? -EAGAIN : 0; 108 } 109 110 111 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 112 { 113 struct fib6_rule *r = (struct fib6_rule *) rule; 114 115 if (r->dst.plen && 116 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 117 return 0; 118 119 /* 120 * If FIB_RULE_FIND_SADDR is set and we do not have a 121 * source address for the traffic, we defer check for 122 * source address. 123 */ 124 if (r->src.plen) { 125 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 126 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 127 r->src.plen)) 128 return 0; 129 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 130 return 0; 131 } 132 133 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 134 return 0; 135 136 return 1; 137 } 138 139 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 140 FRA_GENERIC_POLICY, 141 }; 142 143 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 144 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 145 struct nlattr **tb) 146 { 147 int err = -EINVAL; 148 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 149 150 if (rule->action == FR_ACT_TO_TBL) { 151 if (rule->table == RT6_TABLE_UNSPEC) 152 goto errout; 153 154 if (fib6_new_table(rule->table) == NULL) { 155 err = -ENOBUFS; 156 goto errout; 157 } 158 } 159 160 if (frh->src_len) 161 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 162 sizeof(struct in6_addr)); 163 164 if (frh->dst_len) 165 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 166 sizeof(struct in6_addr)); 167 168 rule6->src.plen = frh->src_len; 169 rule6->dst.plen = frh->dst_len; 170 rule6->tclass = frh->tos; 171 172 err = 0; 173 errout: 174 return err; 175 } 176 177 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 178 struct nlattr **tb) 179 { 180 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 181 182 if (frh->src_len && (rule6->src.plen != frh->src_len)) 183 return 0; 184 185 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 186 return 0; 187 188 if (frh->tos && (rule6->tclass != frh->tos)) 189 return 0; 190 191 if (frh->src_len && 192 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 193 return 0; 194 195 if (frh->dst_len && 196 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 197 return 0; 198 199 return 1; 200 } 201 202 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 203 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 204 { 205 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 206 207 frh->family = AF_INET6; 208 frh->dst_len = rule6->dst.plen; 209 frh->src_len = rule6->src.plen; 210 frh->tos = rule6->tclass; 211 212 if (rule6->dst.plen) 213 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 214 &rule6->dst.addr); 215 216 if (rule6->src.plen) 217 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 218 &rule6->src.addr); 219 220 return 0; 221 222 nla_put_failure: 223 return -ENOBUFS; 224 } 225 226 static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) 227 { 228 return 0x3FFF; 229 } 230 231 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 232 { 233 return nla_total_size(16) /* dst */ 234 + nla_total_size(16); /* src */ 235 } 236 237 static struct fib_rules_ops fib6_rules_ops = { 238 .family = AF_INET6, 239 .rule_size = sizeof(struct fib6_rule), 240 .addr_size = sizeof(struct in6_addr), 241 .action = fib6_rule_action, 242 .match = fib6_rule_match, 243 .configure = fib6_rule_configure, 244 .compare = fib6_rule_compare, 245 .fill = fib6_rule_fill, 246 .default_pref = fib6_rule_default_pref, 247 .nlmsg_payload = fib6_rule_nlmsg_payload, 248 .nlgroup = RTNLGRP_IPV6_RULE, 249 .policy = fib6_rule_policy, 250 .rules_list = LIST_HEAD_INIT(fib6_rules_ops.rules_list), 251 .owner = THIS_MODULE, 252 .fro_net = &init_net, 253 }; 254 255 static int __init fib6_default_rules_init(void) 256 { 257 int err; 258 259 err = fib_default_rule_add(&fib6_rules_ops, 0, 260 RT6_TABLE_LOCAL, FIB_RULE_PERMANENT); 261 if (err < 0) 262 return err; 263 err = fib_default_rule_add(&fib6_rules_ops, 0x7FFE, RT6_TABLE_MAIN, 0); 264 if (err < 0) 265 return err; 266 return 0; 267 } 268 269 int __init fib6_rules_init(void) 270 { 271 int ret; 272 273 ret = fib6_default_rules_init(); 274 if (ret) 275 goto out; 276 277 ret = fib_rules_register(&fib6_rules_ops); 278 if (ret) 279 goto out_default_rules_init; 280 out: 281 return ret; 282 283 out_default_rules_init: 284 fib_rules_cleanup_ops(&fib6_rules_ops); 285 goto out; 286 } 287 288 void fib6_rules_cleanup(void) 289 { 290 fib_rules_unregister(&fib6_rules_ops); 291 } 292