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 (2002-4) 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_common *tcf_ipt_ht[IPT_TAB_MASK + 1]; 33 static u32 ipt_idx_gen; 34 static DEFINE_RWLOCK(ipt_lock); 35 36 static struct tcf_hashinfo ipt_hash_info = { 37 .htab = tcf_ipt_ht, 38 .hmask = IPT_TAB_MASK, 39 .lock = &ipt_lock, 40 }; 41 42 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook) 43 { 44 struct xt_tgchk_param par; 45 struct xt_target *target; 46 int ret = 0; 47 48 target = xt_request_find_target(AF_INET, t->u.user.name, 49 t->u.user.revision); 50 if (IS_ERR(target)) 51 return PTR_ERR(target); 52 53 t->u.kernel.target = target; 54 par.table = table; 55 par.entryinfo = NULL; 56 par.target = target; 57 par.targinfo = t->data; 58 par.hook_mask = hook; 59 par.family = NFPROTO_IPV4; 60 61 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 62 if (ret < 0) { 63 module_put(t->u.kernel.target->me); 64 return ret; 65 } 66 return 0; 67 } 68 69 static void ipt_destroy_target(struct xt_entry_target *t) 70 { 71 struct xt_tgdtor_param par = { 72 .target = t->u.kernel.target, 73 .targinfo = t->data, 74 }; 75 if (par.target->destroy != NULL) 76 par.target->destroy(&par); 77 module_put(par.target->me); 78 } 79 80 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 81 { 82 int ret = 0; 83 if (ipt) { 84 if (bind) 85 ipt->tcf_bindcnt--; 86 ipt->tcf_refcnt--; 87 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 88 ipt_destroy_target(ipt->tcfi_t); 89 kfree(ipt->tcfi_tname); 90 kfree(ipt->tcfi_t); 91 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 92 ret = ACT_P_DELETED; 93 } 94 } 95 return ret; 96 } 97 98 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 99 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 100 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 101 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 102 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, 103 }; 104 105 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est, 106 struct tc_action *a, int ovr, int bind) 107 { 108 struct nlattr *tb[TCA_IPT_MAX + 1]; 109 struct tcf_ipt *ipt; 110 struct tcf_common *pc; 111 struct xt_entry_target *td, *t; 112 char *tname; 113 int ret = 0, err; 114 u32 hook = 0; 115 u32 index = 0; 116 117 if (nla == NULL) 118 return -EINVAL; 119 120 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy); 121 if (err < 0) 122 return err; 123 124 if (tb[TCA_IPT_HOOK] == NULL) 125 return -EINVAL; 126 if (tb[TCA_IPT_TARG] == NULL) 127 return -EINVAL; 128 129 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 130 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) 131 return -EINVAL; 132 133 if (tb[TCA_IPT_INDEX] != NULL) 134 index = nla_get_u32(tb[TCA_IPT_INDEX]); 135 136 pc = tcf_hash_check(index, a, bind, &ipt_hash_info); 137 if (!pc) { 138 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind, 139 &ipt_idx_gen, &ipt_hash_info); 140 if (IS_ERR(pc)) 141 return PTR_ERR(pc); 142 ret = ACT_P_CREATED; 143 } else { 144 if (!ovr) { 145 tcf_ipt_release(to_ipt(pc), bind); 146 return -EEXIST; 147 } 148 } 149 ipt = to_ipt(pc); 150 151 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 152 153 err = -ENOMEM; 154 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 155 if (unlikely(!tname)) 156 goto err1; 157 if (tb[TCA_IPT_TABLE] == NULL || 158 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 159 strcpy(tname, "mangle"); 160 161 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 162 if (unlikely(!t)) 163 goto err2; 164 165 err = ipt_init_target(t, tname, hook); 166 if (err < 0) 167 goto err3; 168 169 spin_lock_bh(&ipt->tcf_lock); 170 if (ret != ACT_P_CREATED) { 171 ipt_destroy_target(ipt->tcfi_t); 172 kfree(ipt->tcfi_tname); 173 kfree(ipt->tcfi_t); 174 } 175 ipt->tcfi_tname = tname; 176 ipt->tcfi_t = t; 177 ipt->tcfi_hook = hook; 178 spin_unlock_bh(&ipt->tcf_lock); 179 if (ret == ACT_P_CREATED) 180 tcf_hash_insert(pc, &ipt_hash_info); 181 return ret; 182 183 err3: 184 kfree(t); 185 err2: 186 kfree(tname); 187 err1: 188 if (ret == ACT_P_CREATED) { 189 if (est) 190 gen_kill_estimator(&pc->tcfc_bstats, 191 &pc->tcfc_rate_est); 192 kfree_rcu(pc, tcfc_rcu); 193 } 194 return err; 195 } 196 197 static int tcf_ipt_cleanup(struct tc_action *a, int bind) 198 { 199 struct tcf_ipt *ipt = a->priv; 200 return tcf_ipt_release(ipt, bind); 201 } 202 203 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a, 204 struct tcf_result *res) 205 { 206 int ret = 0, result = 0; 207 struct tcf_ipt *ipt = a->priv; 208 struct xt_action_param par; 209 210 if (skb_cloned(skb)) { 211 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 212 return TC_ACT_UNSPEC; 213 } 214 215 spin_lock(&ipt->tcf_lock); 216 217 ipt->tcf_tm.lastuse = jiffies; 218 bstats_update(&ipt->tcf_bstats, skb); 219 220 /* yes, we have to worry about both in and out dev 221 * worry later - danger - this API seems to have changed 222 * from earlier kernels 223 */ 224 par.in = skb->dev; 225 par.out = NULL; 226 par.hooknum = ipt->tcfi_hook; 227 par.target = ipt->tcfi_t->u.kernel.target; 228 par.targinfo = ipt->tcfi_t->data; 229 ret = par.target->target(skb, &par); 230 231 switch (ret) { 232 case NF_ACCEPT: 233 result = TC_ACT_OK; 234 break; 235 case NF_DROP: 236 result = TC_ACT_SHOT; 237 ipt->tcf_qstats.drops++; 238 break; 239 case XT_CONTINUE: 240 result = TC_ACT_PIPE; 241 break; 242 default: 243 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 244 ret); 245 result = TC_POLICE_OK; 246 break; 247 } 248 spin_unlock(&ipt->tcf_lock); 249 return result; 250 251 } 252 253 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 254 { 255 unsigned char *b = skb_tail_pointer(skb); 256 struct tcf_ipt *ipt = a->priv; 257 struct xt_entry_target *t; 258 struct tcf_t tm; 259 struct tc_cnt c; 260 261 /* for simple targets kernel size == user size 262 * user name = target name 263 * for foolproof you need to not assume this 264 */ 265 266 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 267 if (unlikely(!t)) 268 goto nla_put_failure; 269 270 c.bindcnt = ipt->tcf_bindcnt - bind; 271 c.refcnt = ipt->tcf_refcnt - ref; 272 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 273 274 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 275 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 276 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 277 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 278 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 279 goto nla_put_failure; 280 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 281 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 282 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 283 if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm)) 284 goto nla_put_failure; 285 kfree(t); 286 return skb->len; 287 288 nla_put_failure: 289 nlmsg_trim(skb, b); 290 kfree(t); 291 return -1; 292 } 293 294 static struct tc_action_ops act_ipt_ops = { 295 .kind = "ipt", 296 .hinfo = &ipt_hash_info, 297 .type = TCA_ACT_IPT, 298 .capab = TCA_CAP_NONE, 299 .owner = THIS_MODULE, 300 .act = tcf_ipt, 301 .dump = tcf_ipt_dump, 302 .cleanup = tcf_ipt_cleanup, 303 .lookup = tcf_hash_search, 304 .init = tcf_ipt_init, 305 .walk = tcf_generic_walker 306 }; 307 308 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 309 MODULE_DESCRIPTION("Iptables target actions"); 310 MODULE_LICENSE("GPL"); 311 312 static int __init ipt_init_module(void) 313 { 314 return tcf_register_action(&act_ipt_ops); 315 } 316 317 static void __exit ipt_cleanup_module(void) 318 { 319 tcf_unregister_action(&act_ipt_ops); 320 } 321 322 module_init(ipt_init_module); 323 module_exit(ipt_cleanup_module); 324