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 { 37 struct fib_rule common; 38 u8 dst_len; 39 u8 src_len; 40 u8 tos; 41 __be32 src; 42 __be32 srcmask; 43 __be32 dst; 44 __be32 dstmask; 45 #ifdef CONFIG_NET_CLS_ROUTE 46 u32 tclassid; 47 #endif 48 }; 49 50 #ifdef CONFIG_NET_CLS_ROUTE 51 u32 fib_rules_tclass(struct fib_result *res) 52 { 53 return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0; 54 } 55 #endif 56 57 int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res) 58 { 59 struct fib_lookup_arg arg = { 60 .result = res, 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 if ((tbl = fib_get_table(rule->fr_net, rule->table)) == NULL) 95 goto errout; 96 97 err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result); 98 if (err > 0) 99 err = -EAGAIN; 100 errout: 101 return err; 102 } 103 104 105 static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags) 106 { 107 struct fib4_rule *r = (struct fib4_rule *) rule; 108 __be32 daddr = fl->fl4_dst; 109 __be32 saddr = fl->fl4_src; 110 111 if (((saddr ^ r->src) & r->srcmask) || 112 ((daddr ^ r->dst) & r->dstmask)) 113 return 0; 114 115 if (r->tos && (r->tos != fl->fl4_tos)) 116 return 0; 117 118 return 1; 119 } 120 121 static struct fib_table *fib_empty_table(struct net *net) 122 { 123 u32 id; 124 125 for (id = 1; id <= RT_TABLE_MAX; id++) 126 if (fib_get_table(net, id) == NULL) 127 return fib_new_table(net, id); 128 return NULL; 129 } 130 131 static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = { 132 FRA_GENERIC_POLICY, 133 [FRA_FLOW] = { .type = NLA_U32 }, 134 }; 135 136 static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb, 137 struct fib_rule_hdr *frh, 138 struct nlattr **tb) 139 { 140 struct net *net = sock_net(skb->sk); 141 int err = -EINVAL; 142 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 143 144 if (frh->tos & ~IPTOS_TOS_MASK) 145 goto errout; 146 147 if (rule->table == RT_TABLE_UNSPEC) { 148 if (rule->action == FR_ACT_TO_TBL) { 149 struct fib_table *table; 150 151 table = fib_empty_table(net); 152 if (table == NULL) { 153 err = -ENOBUFS; 154 goto errout; 155 } 156 157 rule->table = table->tb_id; 158 } 159 } 160 161 if (frh->src_len) 162 rule4->src = nla_get_be32(tb[FRA_SRC]); 163 164 if (frh->dst_len) 165 rule4->dst = nla_get_be32(tb[FRA_DST]); 166 167 #ifdef CONFIG_NET_CLS_ROUTE 168 if (tb[FRA_FLOW]) 169 rule4->tclassid = nla_get_u32(tb[FRA_FLOW]); 170 #endif 171 172 rule4->src_len = frh->src_len; 173 rule4->srcmask = inet_make_mask(rule4->src_len); 174 rule4->dst_len = frh->dst_len; 175 rule4->dstmask = inet_make_mask(rule4->dst_len); 176 rule4->tos = frh->tos; 177 178 err = 0; 179 errout: 180 return err; 181 } 182 183 static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh, 184 struct nlattr **tb) 185 { 186 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 187 188 if (frh->src_len && (rule4->src_len != frh->src_len)) 189 return 0; 190 191 if (frh->dst_len && (rule4->dst_len != frh->dst_len)) 192 return 0; 193 194 if (frh->tos && (rule4->tos != frh->tos)) 195 return 0; 196 197 #ifdef CONFIG_NET_CLS_ROUTE 198 if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW]))) 199 return 0; 200 #endif 201 202 if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC]))) 203 return 0; 204 205 if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST]))) 206 return 0; 207 208 return 1; 209 } 210 211 static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb, 212 struct fib_rule_hdr *frh) 213 { 214 struct fib4_rule *rule4 = (struct fib4_rule *) rule; 215 216 frh->dst_len = rule4->dst_len; 217 frh->src_len = rule4->src_len; 218 frh->tos = rule4->tos; 219 220 if (rule4->dst_len) 221 NLA_PUT_BE32(skb, FRA_DST, rule4->dst); 222 223 if (rule4->src_len) 224 NLA_PUT_BE32(skb, FRA_SRC, rule4->src); 225 226 #ifdef CONFIG_NET_CLS_ROUTE 227 if (rule4->tclassid) 228 NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid); 229 #endif 230 return 0; 231 232 nla_put_failure: 233 return -ENOBUFS; 234 } 235 236 static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule) 237 { 238 return nla_total_size(4) /* dst */ 239 + nla_total_size(4) /* src */ 240 + nla_total_size(4); /* flow */ 241 } 242 243 static void fib4_rule_flush_cache(struct fib_rules_ops *ops) 244 { 245 rt_cache_flush(ops->fro_net, -1); 246 } 247 248 static const struct fib_rules_ops __net_initdata fib4_rules_ops_template = { 249 .family = AF_INET, 250 .rule_size = sizeof(struct fib4_rule), 251 .addr_size = sizeof(u32), 252 .action = fib4_rule_action, 253 .match = fib4_rule_match, 254 .configure = fib4_rule_configure, 255 .compare = fib4_rule_compare, 256 .fill = fib4_rule_fill, 257 .default_pref = fib_default_rule_pref, 258 .nlmsg_payload = fib4_rule_nlmsg_payload, 259 .flush_cache = fib4_rule_flush_cache, 260 .nlgroup = RTNLGRP_IPV4_RULE, 261 .policy = fib4_rule_policy, 262 .owner = THIS_MODULE, 263 }; 264 265 static int fib_default_rules_init(struct fib_rules_ops *ops) 266 { 267 int err; 268 269 err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0); 270 if (err < 0) 271 return err; 272 err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0); 273 if (err < 0) 274 return err; 275 err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0); 276 if (err < 0) 277 return err; 278 return 0; 279 } 280 281 int __net_init fib4_rules_init(struct net *net) 282 { 283 int err; 284 struct fib_rules_ops *ops; 285 286 ops = fib_rules_register(&fib4_rules_ops_template, net); 287 if (IS_ERR(ops)) 288 return PTR_ERR(ops); 289 290 err = fib_default_rules_init(ops); 291 if (err < 0) 292 goto fail; 293 net->ipv4.rules_ops = ops; 294 return 0; 295 296 fail: 297 /* also cleans all rules already added */ 298 fib_rules_unregister(ops); 299 return err; 300 } 301 302 void __net_exit fib4_rules_exit(struct net *net) 303 { 304 fib_rules_unregister(net->ipv4.rules_ops); 305 } 306