| 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 | #include <linux/export.h> |
| 18 | |
| 19 | #include <net/fib_rules.h> |
| 20 | #include <net/ipv6.h> |
| 21 | #include <net/addrconf.h> |
| 22 | #include <net/ip6_route.h> |
| 23 | #include <net/netlink.h> |
| 24 | |
| 25 | struct fib6_rule { |
| 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 flowi6 *fl6, |
| 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, |
| 41 | flowi6_to_flowi(fl6), flags, &arg); |
| 42 | |
| 43 | if (arg.result) |
| 44 | return arg.result; |
| 45 | |
| 46 | dst_hold(&net->ipv6.ip6_null_entry->dst); |
| 47 | return &net->ipv6.ip6_null_entry->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 flowi6 *flp6 = &flp->u.ip6; |
| 54 | struct rt6_info *rt = NULL; |
| 55 | struct fib6_table *table; |
| 56 | struct net *net = rule->fr_net; |
| 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 = net->ipv6.ip6_null_entry; |
| 64 | goto discard_pkt; |
| 65 | default: |
| 66 | case FR_ACT_BLACKHOLE: |
| 67 | rt = net->ipv6.ip6_blk_hole_entry; |
| 68 | goto discard_pkt; |
| 69 | case FR_ACT_PROHIBIT: |
| 70 | rt = net->ipv6.ip6_prohibit_entry; |
| 71 | goto discard_pkt; |
| 72 | } |
| 73 | |
| 74 | table = fib6_get_table(net, rule->table); |
| 75 | if (table) |
| 76 | rt = lookup(net, table, flp6, flags); |
| 77 | |
| 78 | if (rt != net->ipv6.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 | |
| 89 | if (ipv6_dev_get_saddr(net, |
| 90 | ip6_dst_idev(&rt->dst)->dev, |
| 91 | &flp6->daddr, |
| 92 | rt6_flags2srcprefs(flags), |
| 93 | &saddr)) |
| 94 | goto again; |
| 95 | if (!ipv6_prefix_equal(&saddr, &r->src.addr, |
| 96 | r->src.plen)) |
| 97 | goto again; |
| 98 | flp6->saddr = saddr; |
| 99 | } |
| 100 | goto out; |
| 101 | } |
| 102 | again: |
| 103 | ip6_rt_put(rt); |
| 104 | rt = NULL; |
| 105 | goto out; |
| 106 | |
| 107 | discard_pkt: |
| 108 | dst_hold(&rt->dst); |
| 109 | out: |
| 110 | arg->result = rt; |
| 111 | return rt == NULL ? -EAGAIN : 0; |
| 112 | } |
| 113 | |
| 114 | |
| 115 | static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) |
| 116 | { |
| 117 | struct fib6_rule *r = (struct fib6_rule *) rule; |
| 118 | struct flowi6 *fl6 = &fl->u.ip6; |
| 119 | |
| 120 | if (r->dst.plen && |
| 121 | !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen)) |
| 122 | return 0; |
| 123 | |
| 124 | /* |
| 125 | * If FIB_RULE_FIND_SADDR is set and we do not have a |
| 126 | * source address for the traffic, we defer check for |
| 127 | * source address. |
| 128 | */ |
| 129 | if (r->src.plen) { |
| 130 | if (flags & RT6_LOOKUP_F_HAS_SADDR) { |
| 131 | if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr, |
| 132 | r->src.plen)) |
| 133 | return 0; |
| 134 | } else if (!(r->common.flags & FIB_RULE_FIND_SADDR)) |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff)) |
| 139 | return 0; |
| 140 | |
| 141 | return 1; |
| 142 | } |
| 143 | |
| 144 | static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = { |
| 145 | FRA_GENERIC_POLICY, |
| 146 | }; |
| 147 | |
| 148 | static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb, |
| 149 | struct fib_rule_hdr *frh, |
| 150 | struct nlattr **tb) |
| 151 | { |
| 152 | int err = -EINVAL; |
| 153 | struct net *net = sock_net(skb->sk); |
| 154 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
| 155 | |
| 156 | if (rule->action == FR_ACT_TO_TBL) { |
| 157 | if (rule->table == RT6_TABLE_UNSPEC) |
| 158 | goto errout; |
| 159 | |
| 160 | if (fib6_new_table(net, rule->table) == NULL) { |
| 161 | err = -ENOBUFS; |
| 162 | goto errout; |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | if (frh->src_len) |
| 167 | nla_memcpy(&rule6->src.addr, tb[FRA_SRC], |
| 168 | sizeof(struct in6_addr)); |
| 169 | |
| 170 | if (frh->dst_len) |
| 171 | nla_memcpy(&rule6->dst.addr, tb[FRA_DST], |
| 172 | sizeof(struct in6_addr)); |
| 173 | |
| 174 | rule6->src.plen = frh->src_len; |
| 175 | rule6->dst.plen = frh->dst_len; |
| 176 | rule6->tclass = frh->tos; |
| 177 | |
| 178 | err = 0; |
| 179 | errout: |
| 180 | return err; |
| 181 | } |
| 182 | |
| 183 | static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, |
| 184 | struct nlattr **tb) |
| 185 | { |
| 186 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
| 187 | |
| 188 | if (frh->src_len && (rule6->src.plen != frh->src_len)) |
| 189 | return 0; |
| 190 | |
| 191 | if (frh->dst_len && (rule6->dst.plen != frh->dst_len)) |
| 192 | return 0; |
| 193 | |
| 194 | if (frh->tos && (rule6->tclass != frh->tos)) |
| 195 | return 0; |
| 196 | |
| 197 | if (frh->src_len && |
| 198 | nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr))) |
| 199 | return 0; |
| 200 | |
| 201 | if (frh->dst_len && |
| 202 | nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr))) |
| 203 | return 0; |
| 204 | |
| 205 | return 1; |
| 206 | } |
| 207 | |
| 208 | static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb, |
| 209 | struct fib_rule_hdr *frh) |
| 210 | { |
| 211 | struct fib6_rule *rule6 = (struct fib6_rule *) rule; |
| 212 | |
| 213 | frh->dst_len = rule6->dst.plen; |
| 214 | frh->src_len = rule6->src.plen; |
| 215 | frh->tos = rule6->tclass; |
| 216 | |
| 217 | if ((rule6->dst.plen && |
| 218 | nla_put(skb, FRA_DST, sizeof(struct in6_addr), |
| 219 | &rule6->dst.addr)) || |
| 220 | (rule6->src.plen && |
| 221 | nla_put(skb, FRA_SRC, sizeof(struct in6_addr), |
| 222 | &rule6->src.addr))) |
| 223 | goto nla_put_failure; |
| 224 | return 0; |
| 225 | |
| 226 | nla_put_failure: |
| 227 | return -ENOBUFS; |
| 228 | } |
| 229 | |
| 230 | static u32 fib6_rule_default_pref(struct fib_rules_ops *ops) |
| 231 | { |
| 232 | return 0x3FFF; |
| 233 | } |
| 234 | |
| 235 | static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule) |
| 236 | { |
| 237 | return nla_total_size(16) /* dst */ |
| 238 | + nla_total_size(16); /* src */ |
| 239 | } |
| 240 | |
| 241 | static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = { |
| 242 | .family = AF_INET6, |
| 243 | .rule_size = sizeof(struct fib6_rule), |
| 244 | .addr_size = sizeof(struct in6_addr), |
| 245 | .action = fib6_rule_action, |
| 246 | .match = fib6_rule_match, |
| 247 | .configure = fib6_rule_configure, |
| 248 | .compare = fib6_rule_compare, |
| 249 | .fill = fib6_rule_fill, |
| 250 | .default_pref = fib6_rule_default_pref, |
| 251 | .nlmsg_payload = fib6_rule_nlmsg_payload, |
| 252 | .nlgroup = RTNLGRP_IPV6_RULE, |
| 253 | .policy = fib6_rule_policy, |
| 254 | .owner = THIS_MODULE, |
| 255 | .fro_net = &init_net, |
| 256 | }; |
| 257 | |
| 258 | static int __net_init fib6_rules_net_init(struct net *net) |
| 259 | { |
| 260 | struct fib_rules_ops *ops; |
| 261 | int err = -ENOMEM; |
| 262 | |
| 263 | ops = fib_rules_register(&fib6_rules_ops_template, net); |
| 264 | if (IS_ERR(ops)) |
| 265 | return PTR_ERR(ops); |
| 266 | net->ipv6.fib6_rules_ops = ops; |
| 267 | |
| 268 | |
| 269 | err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0, |
| 270 | RT6_TABLE_LOCAL, 0); |
| 271 | if (err) |
| 272 | goto out_fib6_rules_ops; |
| 273 | |
| 274 | err = fib_default_rule_add(net->ipv6.fib6_rules_ops, |
| 275 | 0x7FFE, RT6_TABLE_MAIN, 0); |
| 276 | if (err) |
| 277 | goto out_fib6_rules_ops; |
| 278 | |
| 279 | out: |
| 280 | return err; |
| 281 | |
| 282 | out_fib6_rules_ops: |
| 283 | fib_rules_unregister(ops); |
| 284 | goto out; |
| 285 | } |
| 286 | |
| 287 | static void __net_exit fib6_rules_net_exit(struct net *net) |
| 288 | { |
| 289 | fib_rules_unregister(net->ipv6.fib6_rules_ops); |
| 290 | } |
| 291 | |
| 292 | static struct pernet_operations fib6_rules_net_ops = { |
| 293 | .init = fib6_rules_net_init, |
| 294 | .exit = fib6_rules_net_exit, |
| 295 | }; |
| 296 | |
| 297 | int __init fib6_rules_init(void) |
| 298 | { |
| 299 | return register_pernet_subsys(&fib6_rules_net_ops); |
| 300 | } |
| 301 | |
| 302 | |
| 303 | void fib6_rules_cleanup(void) |
| 304 | { |
| 305 | unregister_pernet_subsys(&fib6_rules_net_ops); |
| 306 | } |