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 static struct fib6_rule main_rule = { 35 .common = { 36 .refcnt = ATOMIC_INIT(2), 37 .pref = 0x7FFE, 38 .action = FR_ACT_TO_TBL, 39 .table = RT6_TABLE_MAIN, 40 }, 41 }; 42 43 static struct fib6_rule local_rule = { 44 .common = { 45 .refcnt = ATOMIC_INIT(2), 46 .pref = 0, 47 .action = FR_ACT_TO_TBL, 48 .table = RT6_TABLE_LOCAL, 49 .flags = FIB_RULE_PERMANENT, 50 }, 51 }; 52 53 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags, 54 pol_lookup_t lookup) 55 { 56 struct fib_lookup_arg arg = { 57 .lookup_ptr = lookup, 58 }; 59 60 fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg); 61 if (arg.rule) 62 fib_rule_put(arg.rule); 63 64 if (arg.result) 65 return arg.result; 66 67 dst_hold(&ip6_null_entry.u.dst); 68 return &ip6_null_entry.u.dst; 69 } 70 71 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 72 int flags, struct fib_lookup_arg *arg) 73 { 74 struct rt6_info *rt = NULL; 75 struct fib6_table *table; 76 pol_lookup_t lookup = arg->lookup_ptr; 77 78 switch (rule->action) { 79 case FR_ACT_TO_TBL: 80 break; 81 case FR_ACT_UNREACHABLE: 82 rt = &ip6_null_entry; 83 goto discard_pkt; 84 default: 85 case FR_ACT_BLACKHOLE: 86 rt = &ip6_blk_hole_entry; 87 goto discard_pkt; 88 case FR_ACT_PROHIBIT: 89 rt = &ip6_prohibit_entry; 90 goto discard_pkt; 91 } 92 93 table = fib6_get_table(rule->table); 94 if (table) 95 rt = lookup(table, flp, flags); 96 97 if (rt != &ip6_null_entry) { 98 struct fib6_rule *r = (struct fib6_rule *)rule; 99 100 /* 101 * If we need to find a source address for this traffic, 102 * we check the result if it meets requirement of the rule. 103 */ 104 if ((rule->flags & FIB_RULE_FIND_SADDR) && 105 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 106 struct in6_addr saddr; 107 if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst, 108 &saddr)) 109 goto again; 110 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 111 r->src.plen)) 112 goto again; 113 ipv6_addr_copy(&flp->fl6_src, &saddr); 114 } 115 goto out; 116 } 117 again: 118 dst_release(&rt->u.dst); 119 rt = NULL; 120 goto out; 121 122 discard_pkt: 123 dst_hold(&rt->u.dst); 124 out: 125 arg->result = rt; 126 return rt == NULL ? -EAGAIN : 0; 127 } 128 129 130 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 131 { 132 struct fib6_rule *r = (struct fib6_rule *) rule; 133 134 if (r->dst.plen && 135 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 136 return 0; 137 138 /* 139 * If FIB_RULE_FIND_SADDR is set and we do not have a 140 * source address for the traffic, we defer check for 141 * source address. 142 */ 143 if (r->src.plen) { 144 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 145 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 146 r->src.plen)) 147 return 0; 148 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 149 return 0; 150 } 151 152 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 153 return 0; 154 155 return 1; 156 } 157 158 static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { 159 FRA_GENERIC_POLICY, 160 }; 161 162 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 163 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 164 struct nlattr **tb) 165 { 166 int err = -EINVAL; 167 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 168 169 if (rule->action == FR_ACT_TO_TBL) { 170 if (rule->table == RT6_TABLE_UNSPEC) 171 goto errout; 172 173 if (fib6_new_table(rule->table) == NULL) { 174 err = -ENOBUFS; 175 goto errout; 176 } 177 } 178 179 if (frh->src_len) 180 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 181 sizeof(struct in6_addr)); 182 183 if (frh->dst_len) 184 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 185 sizeof(struct in6_addr)); 186 187 rule6->src.plen = frh->src_len; 188 rule6->dst.plen = frh->dst_len; 189 rule6->tclass = frh->tos; 190 191 err = 0; 192 errout: 193 return err; 194 } 195 196 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 197 struct nlattr **tb) 198 { 199 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 200 201 if (frh->src_len && (rule6->src.plen != frh->src_len)) 202 return 0; 203 204 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 205 return 0; 206 207 if (frh->tos && (rule6->tclass != frh->tos)) 208 return 0; 209 210 if (frh->src_len && 211 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 212 return 0; 213 214 if (frh->dst_len && 215 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 216 return 0; 217 218 return 1; 219 } 220 221 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 222 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 223 { 224 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 225 226 frh->family = AF_INET6; 227 frh->dst_len = rule6->dst.plen; 228 frh->src_len = rule6->src.plen; 229 frh->tos = rule6->tclass; 230 231 if (rule6->dst.plen) 232 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 233 &rule6->dst.addr); 234 235 if (rule6->src.plen) 236 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 237 &rule6->src.addr); 238 239 return 0; 240 241 nla_put_failure: 242 return -ENOBUFS; 243 } 244 245 static u32 fib6_rule_default_pref(void) 246 { 247 return 0x3FFF; 248 } 249 250 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 251 { 252 return nla_total_size(16) /* dst */ 253 + nla_total_size(16); /* src */ 254 } 255 256 static struct fib_rules_ops fib6_rules_ops = { 257 .family = AF_INET6, 258 .rule_size = sizeof(struct fib6_rule), 259 .addr_size = sizeof(struct in6_addr), 260 .action = fib6_rule_action, 261 .match = fib6_rule_match, 262 .configure = fib6_rule_configure, 263 .compare = fib6_rule_compare, 264 .fill = fib6_rule_fill, 265 .default_pref = fib6_rule_default_pref, 266 .nlmsg_payload = fib6_rule_nlmsg_payload, 267 .nlgroup = RTNLGRP_IPV6_RULE, 268 .policy = fib6_rule_policy, 269 .rules_list = LIST_HEAD_INIT(fib6_rules_ops.rules_list), 270 .owner = THIS_MODULE, 271 }; 272 273 void __init fib6_rules_init(void) 274 { 275 list_add_tail(&local_rule.common.list, &fib6_rules_ops.rules_list); 276 list_add_tail(&main_rule.common.list, &fib6_rules_ops.rules_list); 277 278 fib_rules_register(&fib6_rules_ops); 279 } 280 281 void fib6_rules_cleanup(void) 282 { 283 fib_rules_unregister(&fib6_rules_ops); 284 } 285