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 static LIST_HEAD(fib6_rules); 54 55 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags, 56 pol_lookup_t lookup) 57 { 58 struct fib_lookup_arg arg = { 59 .lookup_ptr = lookup, 60 }; 61 62 fib_rules_lookup(&fib6_rules_ops, fl, flags, &arg); 63 if (arg.rule) 64 fib_rule_put(arg.rule); 65 66 if (arg.result) 67 return arg.result; 68 69 dst_hold(&ip6_null_entry.u.dst); 70 return &ip6_null_entry.u.dst; 71 } 72 73 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp, 74 int flags, struct fib_lookup_arg *arg) 75 { 76 struct rt6_info *rt = NULL; 77 struct fib6_table *table; 78 pol_lookup_t lookup = arg->lookup_ptr; 79 80 switch (rule->action) { 81 case FR_ACT_TO_TBL: 82 break; 83 case FR_ACT_UNREACHABLE: 84 rt = &ip6_null_entry; 85 goto discard_pkt; 86 default: 87 case FR_ACT_BLACKHOLE: 88 rt = &ip6_blk_hole_entry; 89 goto discard_pkt; 90 case FR_ACT_PROHIBIT: 91 rt = &ip6_prohibit_entry; 92 goto discard_pkt; 93 } 94 95 table = fib6_get_table(rule->table); 96 if (table) 97 rt = lookup(table, flp, flags); 98 99 if (rt != &ip6_null_entry) { 100 struct fib6_rule *r = (struct fib6_rule *)rule; 101 102 /* 103 * If we need to find a source address for this traffic, 104 * we check the result if it meets requirement of the rule. 105 */ 106 if ((rule->flags & FIB_RULE_FIND_SADDR) && 107 r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) { 108 struct in6_addr saddr; 109 if (ipv6_get_saddr(&rt->u.dst, &flp->fl6_dst, 110 &saddr)) 111 goto again; 112 if (!ipv6_prefix_equal(&saddr, &r->src.addr, 113 r->src.plen)) 114 goto again; 115 ipv6_addr_copy(&flp->fl6_src, &saddr); 116 } 117 goto out; 118 } 119 again: 120 dst_release(&rt->u.dst); 121 rt = NULL; 122 goto out; 123 124 discard_pkt: 125 dst_hold(&rt->u.dst); 126 out: 127 arg->result = rt; 128 return rt == NULL ? -EAGAIN : 0; 129 } 130 131 132 static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 133 { 134 struct fib6_rule *r = (struct fib6_rule *) rule; 135 136 if (r->dst.plen && 137 !ipv6_prefix_equal(&fl->fl6_dst, &r->dst.addr, r->dst.plen)) 138 return 0; 139 140 /* 141 * If FIB_RULE_FIND_SADDR is set and we do not have a 142 * source address for the traffic, we defer check for 143 * source address. 144 */ 145 if (r->src.plen) { 146 if (flags & RT6_LOOKUP_F_HAS_SADDR) { 147 if (!ipv6_prefix_equal(&fl->fl6_src, &r->src.addr, 148 r->src.plen)) 149 return 0; 150 } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) 151 return 0; 152 } 153 154 if (r->tclass && r->tclass != ((ntohl(fl->fl6_flowlabel) >> 20) & 0xff)) 155 return 0; 156 157 return 1; 158 } 159 160 static struct nla_policy fib6_rule_policy[FRA_MAX+1] __read_mostly = { 161 FRA_GENERIC_POLICY, 162 }; 163 164 static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 165 struct nlmsghdr *nlh, struct fib_rule_hdr *frh, 166 struct nlattr **tb) 167 { 168 int err = -EINVAL; 169 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 170 171 if (rule->action == FR_ACT_TO_TBL) { 172 if (rule->table == RT6_TABLE_UNSPEC) 173 goto errout; 174 175 if (fib6_new_table(rule->table) == NULL) { 176 err = -ENOBUFS; 177 goto errout; 178 } 179 } 180 181 if (frh->src_len) 182 nla_memcpy(&rule6->src.addr, tb[FRA_SRC], 183 sizeof(struct in6_addr)); 184 185 if (frh->dst_len) 186 nla_memcpy(&rule6->dst.addr, tb[FRA_DST], 187 sizeof(struct in6_addr)); 188 189 rule6->src.plen = frh->src_len; 190 rule6->dst.plen = frh->dst_len; 191 rule6->tclass = frh->tos; 192 193 err = 0; 194 errout: 195 return err; 196 } 197 198 static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 199 struct nlattr **tb) 200 { 201 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 202 203 if (frh->src_len && (rule6->src.plen != frh->src_len)) 204 return 0; 205 206 if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) 207 return 0; 208 209 if (frh->tos && (rule6->tclass != frh->tos)) 210 return 0; 211 212 if (frh->src_len && 213 nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) 214 return 0; 215 216 if (frh->dst_len && 217 nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) 218 return 0; 219 220 return 1; 221 } 222 223 static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 224 struct nlmsghdr *nlh, struct fib_rule_hdr *frh) 225 { 226 struct fib6_rule *rule6 = (struct fib6_rule *) rule; 227 228 frh->family = AF_INET6; 229 frh->dst_len = rule6->dst.plen; 230 frh->src_len = rule6->src.plen; 231 frh->tos = rule6->tclass; 232 233 if (rule6->dst.plen) 234 NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr), 235 &rule6->dst.addr); 236 237 if (rule6->src.plen) 238 NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr), 239 &rule6->src.addr); 240 241 return 0; 242 243 nla_put_failure: 244 return -ENOBUFS; 245 } 246 247 static u32 fib6_rule_default_pref(void) 248 { 249 return 0x3FFF; 250 } 251 252 static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) 253 { 254 return nla_total_size(16) /* dst */ 255 + nla_total_size(16); /* src */ 256 } 257 258 static struct fib_rules_ops fib6_rules_ops = { 259 .family = AF_INET6, 260 .rule_size = sizeof(struct fib6_rule), 261 .addr_size = sizeof(struct in6_addr), 262 .action = fib6_rule_action, 263 .match = fib6_rule_match, 264 .configure = fib6_rule_configure, 265 .compare = fib6_rule_compare, 266 .fill = fib6_rule_fill, 267 .default_pref = fib6_rule_default_pref, 268 .nlmsg_payload = fib6_rule_nlmsg_payload, 269 .nlgroup = RTNLGRP_IPV6_RULE, 270 .policy = fib6_rule_policy, 271 .rules_list = &fib6_rules, 272 .owner = THIS_MODULE, 273 }; 274 275 void __init fib6_rules_init(void) 276 { 277 list_add_tail(&local_rule.common.list, &fib6_rules); 278 list_add_tail(&main_rule.common.list, &fib6_rules); 279 280 fib_rules_register(&fib6_rules_ops); 281 } 282 283 void fib6_rules_cleanup(void) 284 { 285 fib_rules_unregister(&fib6_rules_ops); 286 } 287