1 /* 2 * net/sched/ipt.c iptables target interface 3 * 4 *TODO: Add other tables. For now we only support the ipv4 table targets 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * Copyright: Jamal Hadi Salim (2002-13) 12 */ 13 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/string.h> 17 #include <linux/errno.h> 18 #include <linux/skbuff.h> 19 #include <linux/rtnetlink.h> 20 #include <linux/module.h> 21 #include <linux/init.h> 22 #include <linux/slab.h> 23 #include <net/netlink.h> 24 #include <net/pkt_sched.h> 25 #include <linux/tc_act/tc_ipt.h> 26 #include <net/tc_act/tc_ipt.h> 27 28 #include <linux/netfilter_ipv4/ip_tables.h> 29 30 31 #define IPT_TAB_MASK 15 32 static struct tcf_hashinfo ipt_hash_info; 33 34 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook) 35 { 36 struct xt_tgchk_param par; 37 struct xt_target *target; 38 int ret = 0; 39 40 target = xt_request_find_target(AF_INET, t->u.user.name, 41 t->u.user.revision); 42 if (IS_ERR(target)) 43 return PTR_ERR(target); 44 45 t->u.kernel.target = target; 46 par.table = table; 47 par.entryinfo = NULL; 48 par.target = target; 49 par.targinfo = t->data; 50 par.hook_mask = hook; 51 par.family = NFPROTO_IPV4; 52 53 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 54 if (ret < 0) { 55 module_put(t->u.kernel.target->me); 56 return ret; 57 } 58 return 0; 59 } 60 61 static void ipt_destroy_target(struct xt_entry_target *t) 62 { 63 struct xt_tgdtor_param par = { 64 .target = t->u.kernel.target, 65 .targinfo = t->data, 66 }; 67 if (par.target->destroy != NULL) 68 par.target->destroy(&par); 69 module_put(par.target->me); 70 } 71 72 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 73 { 74 int ret = 0; 75 if (ipt) { 76 if (bind) 77 ipt->tcf_bindcnt--; 78 ipt->tcf_refcnt--; 79 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 80 ipt_destroy_target(ipt->tcfi_t); 81 kfree(ipt->tcfi_tname); 82 kfree(ipt->tcfi_t); 83 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 84 ret = ACT_P_DELETED; 85 } 86 } 87 return ret; 88 } 89 90 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 91 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 92 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 93 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 94 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, 95 }; 96 97 static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est, 98 struct tc_action *a, int ovr, int bind) 99 { 100 struct nlattr *tb[TCA_IPT_MAX + 1]; 101 struct tcf_ipt *ipt; 102 struct tcf_common *pc; 103 struct xt_entry_target *td, *t; 104 char *tname; 105 int ret = 0, err; 106 u32 hook = 0; 107 u32 index = 0; 108 109 if (nla == NULL) 110 return -EINVAL; 111 112 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy); 113 if (err < 0) 114 return err; 115 116 if (tb[TCA_IPT_HOOK] == NULL) 117 return -EINVAL; 118 if (tb[TCA_IPT_TARG] == NULL) 119 return -EINVAL; 120 121 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 122 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) 123 return -EINVAL; 124 125 if (tb[TCA_IPT_INDEX] != NULL) 126 index = nla_get_u32(tb[TCA_IPT_INDEX]); 127 128 pc = tcf_hash_check(index, a, bind); 129 if (!pc) { 130 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind); 131 if (IS_ERR(pc)) 132 return PTR_ERR(pc); 133 ret = ACT_P_CREATED; 134 } else { 135 if (bind)/* dont override defaults */ 136 return 0; 137 tcf_ipt_release(to_ipt(pc), bind); 138 139 if (!ovr) 140 return -EEXIST; 141 } 142 ipt = to_ipt(pc); 143 144 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 145 146 err = -ENOMEM; 147 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 148 if (unlikely(!tname)) 149 goto err1; 150 if (tb[TCA_IPT_TABLE] == NULL || 151 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 152 strcpy(tname, "mangle"); 153 154 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 155 if (unlikely(!t)) 156 goto err2; 157 158 err = ipt_init_target(t, tname, hook); 159 if (err < 0) 160 goto err3; 161 162 spin_lock_bh(&ipt->tcf_lock); 163 if (ret != ACT_P_CREATED) { 164 ipt_destroy_target(ipt->tcfi_t); 165 kfree(ipt->tcfi_tname); 166 kfree(ipt->tcfi_t); 167 } 168 ipt->tcfi_tname = tname; 169 ipt->tcfi_t = t; 170 ipt->tcfi_hook = hook; 171 spin_unlock_bh(&ipt->tcf_lock); 172 if (ret == ACT_P_CREATED) 173 tcf_hash_insert(pc, a->ops->hinfo); 174 return ret; 175 176 err3: 177 kfree(t); 178 err2: 179 kfree(tname); 180 err1: 181 if (ret == ACT_P_CREATED) { 182 if (est) 183 gen_kill_estimator(&pc->tcfc_bstats, 184 &pc->tcfc_rate_est); 185 kfree_rcu(pc, tcfc_rcu); 186 } 187 return err; 188 } 189 190 static int tcf_ipt_cleanup(struct tc_action *a, int bind) 191 { 192 struct tcf_ipt *ipt = a->priv; 193 return tcf_ipt_release(ipt, bind); 194 } 195 196 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a, 197 struct tcf_result *res) 198 { 199 int ret = 0, result = 0; 200 struct tcf_ipt *ipt = a->priv; 201 struct xt_action_param par; 202 203 if (skb_unclone(skb, GFP_ATOMIC)) 204 return TC_ACT_UNSPEC; 205 206 spin_lock(&ipt->tcf_lock); 207 208 ipt->tcf_tm.lastuse = jiffies; 209 bstats_update(&ipt->tcf_bstats, skb); 210 211 /* yes, we have to worry about both in and out dev 212 * worry later - danger - this API seems to have changed 213 * from earlier kernels 214 */ 215 par.in = skb->dev; 216 par.out = NULL; 217 par.hooknum = ipt->tcfi_hook; 218 par.target = ipt->tcfi_t->u.kernel.target; 219 par.targinfo = ipt->tcfi_t->data; 220 ret = par.target->target(skb, &par); 221 222 switch (ret) { 223 case NF_ACCEPT: 224 result = TC_ACT_OK; 225 break; 226 case NF_DROP: 227 result = TC_ACT_SHOT; 228 ipt->tcf_qstats.drops++; 229 break; 230 case XT_CONTINUE: 231 result = TC_ACT_PIPE; 232 break; 233 default: 234 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 235 ret); 236 result = TC_POLICE_OK; 237 break; 238 } 239 spin_unlock(&ipt->tcf_lock); 240 return result; 241 242 } 243 244 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 245 { 246 unsigned char *b = skb_tail_pointer(skb); 247 struct tcf_ipt *ipt = a->priv; 248 struct xt_entry_target *t; 249 struct tcf_t tm; 250 struct tc_cnt c; 251 252 /* for simple targets kernel size == user size 253 * user name = target name 254 * for foolproof you need to not assume this 255 */ 256 257 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 258 if (unlikely(!t)) 259 goto nla_put_failure; 260 261 c.bindcnt = ipt->tcf_bindcnt - bind; 262 c.refcnt = ipt->tcf_refcnt - ref; 263 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 264 265 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 266 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 267 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 268 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 269 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 270 goto nla_put_failure; 271 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 272 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 273 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 274 if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm)) 275 goto nla_put_failure; 276 kfree(t); 277 return skb->len; 278 279 nla_put_failure: 280 nlmsg_trim(skb, b); 281 kfree(t); 282 return -1; 283 } 284 285 static struct tc_action_ops act_ipt_ops = { 286 .kind = "ipt", 287 .hinfo = &ipt_hash_info, 288 .type = TCA_ACT_IPT, 289 .owner = THIS_MODULE, 290 .act = tcf_ipt, 291 .dump = tcf_ipt_dump, 292 .cleanup = tcf_ipt_cleanup, 293 .init = tcf_ipt_init, 294 }; 295 296 static struct tc_action_ops act_xt_ops = { 297 .kind = "xt", 298 .hinfo = &ipt_hash_info, 299 .type = TCA_ACT_XT, 300 .owner = THIS_MODULE, 301 .act = tcf_ipt, 302 .dump = tcf_ipt_dump, 303 .cleanup = tcf_ipt_cleanup, 304 .init = tcf_ipt_init, 305 }; 306 307 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 308 MODULE_DESCRIPTION("Iptables target actions"); 309 MODULE_LICENSE("GPL"); 310 MODULE_ALIAS("act_xt"); 311 312 static int __init ipt_init_module(void) 313 { 314 int ret1, ret2, err; 315 err = tcf_hashinfo_init(&ipt_hash_info, IPT_TAB_MASK); 316 if (err) 317 return err; 318 319 ret1 = tcf_register_action(&act_xt_ops); 320 if (ret1 < 0) 321 printk("Failed to load xt action\n"); 322 ret2 = tcf_register_action(&act_ipt_ops); 323 if (ret2 < 0) 324 printk("Failed to load ipt action\n"); 325 326 if (ret1 < 0 && ret2 < 0) { 327 tcf_hashinfo_destroy(&ipt_hash_info); 328 return ret1; 329 } else 330 return 0; 331 } 332 333 static void __exit ipt_cleanup_module(void) 334 { 335 tcf_unregister_action(&act_xt_ops); 336 tcf_unregister_action(&act_ipt_ops); 337 tcf_hashinfo_destroy(&ipt_hash_info); 338 } 339 340 module_init(ipt_init_module); 341 module_exit(ipt_cleanup_module); 342