1 /* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * IPv4 Forwarding Information Base: policy rules. 7 * 8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 9 * Thomas Graf <tgraf@suug.ch> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * Fixes: 17 * Rani Assaf : local_rule cannot be deleted 18 * Marc Boucher : routing by fwmark 19 */ 20 21 #include <linux/types.h> 22 #include <linux/kernel.h> 23 #include <linux/netdevice.h> 24 #include <linux/netlink.h> 25 #include <linux/inetdevice.h> 26 #include <linux/init.h> 27 #include <linux/list.h> 28 #include <linux/rcupdate.h> 29 #include <net/ip.h> 30 #include <net/route.h> 31 #include <net/tcp.h> 32 #include <net/ip_fib.h> 33 #include <net/fib_rules.h> 34 35 struct fib4_rule { 36 struct fib_rule common; 37 u8 dst_len; 38 u8 src_len; 39 u8 tos; 40 __be32 src; 41 __be32 srcmask; 42 __be32 dst; 43 __be32 dstmask; 44 #ifdef CONFIG_NET_CLS_ROUTE 45 u32 tclassid; 46 #endif 47 }; 48 49 #ifdef CONFIG_NET_CLS_ROUTE 50 u32 fib_rules_tclass(struct fib_result *res) 51 { 52 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; 53 } 54 #endif 55 56 int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res) 57 { 58 struct fib_lookup_arg arg = { 59 .result = res, 60 .flags = FIB_LOOKUP_NOREF, 61 }; 62 int err; 63 64 err = fib_rules_lookup(net->ipv4.rules_ops, flp, 0, &arg); 65 res->r = arg.rule; 66 67 return err; 68 } 69 70 static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp, 71 int flags, struct fib_lookup_arg *arg) 72 { 73 int err = -EAGAIN; 74 struct fib_table *tbl; 75 76 switch (rule->action) { 77 case FR_ACT_TO_TBL: 78 break; 79 80 case FR_ACT_UNREACHABLE: 81 err = -ENETUNREACH; 82 goto errout; 83 84 case FR_ACT_PROHIBIT: 85 err = -EACCES; 86 goto errout; 87 88 case FR_ACT_BLACKHOLE: 89 default: 90 err = -EINVAL; 91 goto errout; 92 } 93 94 tbl = fib_get_table(rule->fr_net, rule->table); 95 if (!tbl) 96 goto errout; 97 98 err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result, arg->flags); 99 if (err > 0) 100 err = -EAGAIN; 101 errout: 102 return err; 103 } 104 105 106 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 107 { 108 struct fib4_rule *r = (struct fib4_rule *) rule; 109 __be32 daddr = fl->fl4_dst; 110 __be32 saddr = fl->fl4_src; 111 112 if (((saddr ^ r->src) & r->srcmask) || 113 ((daddr ^ r->dst) & r->dstmask)) 114 return 0; 115 116 if (r->tos && (r->tos != fl->fl4_tos)) 117 return 0; 118 119 return 1; 120 } 121 122 static struct fib_table *fib_empty_table(struct net *net) 123 { 124 u32 id; 125 126 for (id = 1; id <= RT_TABLE_MAX; id++) 127 if (fib_get_table(net, id) == NULL) 128 return fib_new_table(net, id); 129 return NULL; 130 } 131 132 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 133 FRA_GENERIC_POLICY, 134 [FRA_FLOW] = { .type = NLA_U32 }, 135 }; 136 137 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 138 struct fib_rule_hdr *frh, 139 struct nlattr **tb) 140 { 141 struct net *net = sock_net(skb->sk); 142 int err = -EINVAL; 143 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 144 145 if (frh->tos & ~IPTOS_TOS_MASK) 146 goto errout; 147 148 if (rule->table == RT_TABLE_UNSPEC) { 149 if (rule->action == FR_ACT_TO_TBL) { 150 struct fib_table *table; 151 152 table = fib_empty_table(net); 153 if (table == NULL) { 154 err = -ENOBUFS; 155 goto errout; 156 } 157 158 rule->table = table->tb_id; 159 } 160 } 161 162 if (frh->src_len) 163 rule4->src = nla_get_be32(tb[FRA_SRC]); 164 165 if (frh->dst_len) 166 rule4->dst = nla_get_be32(tb[FRA_DST]); 167 168 #ifdef CONFIG_NET_CLS_ROUTE 169 if (tb[FRA_FLOW]) 170 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 171 #endif 172 173 rule4->src_len = frh->src_len; 174 rule4->srcmask = inet_make_mask(rule4->src_len); 175 rule4->dst_len = frh->dst_len; 176 rule4->dstmask = inet_make_mask(rule4->dst_len); 177 rule4->tos = frh->tos; 178 179 err = 0; 180 errout: 181 return err; 182 } 183 184 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 185 struct nlattr **tb) 186 { 187 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 188 189 if (frh->src_len && (rule4->src_len != frh->src_len)) 190 return 0; 191 192 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 193 return 0; 194 195 if (frh->tos && (rule4->tos != frh->tos)) 196 return 0; 197 198 #ifdef CONFIG_NET_CLS_ROUTE 199 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 200 return 0; 201 #endif 202 203 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 204 return 0; 205 206 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 207 return 0; 208 209 return 1; 210 } 211 212 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 213 struct fib_rule_hdr *frh) 214 { 215 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 216 217 frh->dst_len = rule4->dst_len; 218 frh->src_len = rule4->src_len; 219 frh->tos = rule4->tos; 220 221 if (rule4->dst_len) 222 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 223 224 if (rule4->src_len) 225 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 226 227 #ifdef CONFIG_NET_CLS_ROUTE 228 if (rule4->tclassid) 229 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 230 #endif 231 return 0; 232 233 nla_put_failure: 234 return -ENOBUFS; 235 } 236 237 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 238 { 239 return nla_total_size(4) /* dst */ 240 + nla_total_size(4) /* src */ 241 + nla_total_size(4); /* flow */ 242 } 243 244 static void fib4_rule_flush_cache(struct fib_rules_ops *ops) 245 { 246 rt_cache_flush(ops->fro_net, -1); 247 } 248 249 static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = { 250 .family = AF_INET, 251 .rule_size = sizeof(struct fib4_rule), 252 .addr_size = sizeof(u32), 253 .action = fib4_rule_action, 254 .match = fib4_rule_match, 255 .configure = fib4_rule_configure, 256 .compare = fib4_rule_compare, 257 .fill = fib4_rule_fill, 258 .default_pref = fib_default_rule_pref, 259 .nlmsg_payload = fib4_rule_nlmsg_payload, 260 .flush_cache = fib4_rule_flush_cache, 261 .nlgroup = RTNLGRP_IPV4_RULE, 262 .policy = fib4_rule_policy, 263 .owner = THIS_MODULE, 264 }; 265 266 static int fib_default_rules_init(struct fib_rules_ops *ops) 267 { 268 int err; 269 270 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); 271 if (err < 0) 272 return err; 273 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); 274 if (err < 0) 275 return err; 276 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); 277 if (err < 0) 278 return err; 279 return 0; 280 } 281 282 int __net_init fib4_rules_init(struct net *net) 283 { 284 int err; 285 struct fib_rules_ops *ops; 286 287 ops = fib_rules_register(&fib4_rules_ops_template, net); 288 if (IS_ERR(ops)) 289 return PTR_ERR(ops); 290 291 err = fib_default_rules_init(ops); 292 if (err < 0) 293 goto fail; 294 net->ipv4.rules_ops = ops; 295 return 0; 296 297 fail: 298 /* also cleans all rules already added */ 299 fib_rules_unregister(ops); 300 return err; 301 } 302 303 void __net_exit fib4_rules_exit(struct net *net) 304 { 305 fib_rules_unregister(net->ipv4.rules_ops); 306 } 307