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 <net/netlink.h> 23 #include <net/pkt_sched.h> 24 #include <linux/tc_act/tc_ipt.h> 25 #include <net/tc_act/tc_ipt.h> 26 27 #include <linux/netfilter_ipv4/ip_tables.h> 28 29 30 #define IPT_TAB_MASK 15 31 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1]; 32 static u32 ipt_idx_gen; 33 static DEFINE_RWLOCK(ipt_lock); 34 35 static struct tcf_hashinfo ipt_hash_info = { 36 .htab = tcf_ipt_ht, 37 .hmask = IPT_TAB_MASK, 38 .lock = &ipt_lock, 39 }; 40 41 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook) 42 { 43 struct xt_tgchk_param par; 44 struct xt_target *target; 45 int ret = 0; 46 47 target = xt_request_find_target(AF_INET, t->u.user.name, 48 t->u.user.revision); 49 if (!target) 50 return -ENOENT; 51 52 t->u.kernel.target = target; 53 par.table = table; 54 par.entryinfo = NULL; 55 par.target = target; 56 par.targinfo = t->data; 57 par.hook_mask = hook; 58 par.family = NFPROTO_IPV4; 59 60 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 61 if (ret < 0) { 62 module_put(t->u.kernel.target->me); 63 return ret; 64 } 65 return 0; 66 } 67 68 static void ipt_destroy_target(struct ipt_entry_target *t) 69 { 70 struct xt_tgdtor_param par = { 71 .target = t->u.kernel.target, 72 .targinfo = t->data, 73 }; 74 if (par.target->destroy != NULL) 75 par.target->destroy(&par); 76 module_put(par.target->me); 77 } 78 79 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 80 { 81 int ret = 0; 82 if (ipt) { 83 if (bind) 84 ipt->tcf_bindcnt--; 85 ipt->tcf_refcnt--; 86 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 87 ipt_destroy_target(ipt->tcfi_t); 88 kfree(ipt->tcfi_tname); 89 kfree(ipt->tcfi_t); 90 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 91 ret = ACT_P_DELETED; 92 } 93 } 94 return ret; 95 } 96 97 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 98 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 99 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 100 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 101 [TCA_IPT_TARG] = { .len = sizeof(struct ipt_entry_target) }, 102 }; 103 104 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est, 105 struct tc_action *a, int ovr, int bind) 106 { 107 struct nlattr *tb[TCA_IPT_MAX + 1]; 108 struct tcf_ipt *ipt; 109 struct tcf_common *pc; 110 struct ipt_entry_target *td, *t; 111 char *tname; 112 int ret = 0, err; 113 u32 hook = 0; 114 u32 index = 0; 115 116 if (nla == NULL) 117 return -EINVAL; 118 119 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy); 120 if (err < 0) 121 return err; 122 123 if (tb[TCA_IPT_HOOK] == NULL) 124 return -EINVAL; 125 if (tb[TCA_IPT_TARG] == NULL) 126 return -EINVAL; 127 128 td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 129 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) 130 return -EINVAL; 131 132 if (tb[TCA_IPT_INDEX] != NULL) 133 index = nla_get_u32(tb[TCA_IPT_INDEX]); 134 135 pc = tcf_hash_check(index, a, bind, &ipt_hash_info); 136 if (!pc) { 137 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind, 138 &ipt_idx_gen, &ipt_hash_info); 139 if (IS_ERR(pc)) 140 return PTR_ERR(pc); 141 ret = ACT_P_CREATED; 142 } else { 143 if (!ovr) { 144 tcf_ipt_release(to_ipt(pc), bind); 145 return -EEXIST; 146 } 147 } 148 ipt = to_ipt(pc); 149 150 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 151 152 err = -ENOMEM; 153 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 154 if (unlikely(!tname)) 155 goto err1; 156 if (tb[TCA_IPT_TABLE] == NULL || 157 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 158 strcpy(tname, "mangle"); 159 160 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 161 if (unlikely(!t)) 162 goto err2; 163 164 if ((err = ipt_init_target(t, tname, hook)) < 0) 165 goto err3; 166 167 spin_lock_bh(&ipt->tcf_lock); 168 if (ret != ACT_P_CREATED) { 169 ipt_destroy_target(ipt->tcfi_t); 170 kfree(ipt->tcfi_tname); 171 kfree(ipt->tcfi_t); 172 } 173 ipt->tcfi_tname = tname; 174 ipt->tcfi_t = t; 175 ipt->tcfi_hook = hook; 176 spin_unlock_bh(&ipt->tcf_lock); 177 if (ret == ACT_P_CREATED) 178 tcf_hash_insert(pc, &ipt_hash_info); 179 return ret; 180 181 err3: 182 kfree(t); 183 err2: 184 kfree(tname); 185 err1: 186 kfree(pc); 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, 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_target_param par; 202 203 if (skb_cloned(skb)) { 204 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 205 return TC_ACT_UNSPEC; 206 } 207 208 spin_lock(&ipt->tcf_lock); 209 210 ipt->tcf_tm.lastuse = jiffies; 211 ipt->tcf_bstats.bytes += qdisc_pkt_len(skb); 212 ipt->tcf_bstats.packets++; 213 214 /* yes, we have to worry about both in and out dev 215 worry later - danger - this API seems to have changed 216 from earlier kernels */ 217 par.in = skb->dev; 218 par.out = NULL; 219 par.hooknum = ipt->tcfi_hook; 220 par.target = ipt->tcfi_t->u.kernel.target; 221 par.targinfo = ipt->tcfi_t->data; 222 ret = par.target->target(skb, &par); 223 224 switch (ret) { 225 case NF_ACCEPT: 226 result = TC_ACT_OK; 227 break; 228 case NF_DROP: 229 result = TC_ACT_SHOT; 230 ipt->tcf_qstats.drops++; 231 break; 232 case IPT_CONTINUE: 233 result = TC_ACT_PIPE; 234 break; 235 default: 236 if (net_ratelimit()) 237 printk("Bogus netfilter code %d assume ACCEPT\n", ret); 238 result = TC_POLICE_OK; 239 break; 240 } 241 spin_unlock(&ipt->tcf_lock); 242 return result; 243 244 } 245 246 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 247 { 248 unsigned char *b = skb_tail_pointer(skb); 249 struct tcf_ipt *ipt = a->priv; 250 struct ipt_entry_target *t; 251 struct tcf_t tm; 252 struct tc_cnt c; 253 254 /* for simple targets kernel size == user size 255 ** user name = target name 256 ** for foolproof you need to not assume this 257 */ 258 259 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 260 if (unlikely(!t)) 261 goto nla_put_failure; 262 263 c.bindcnt = ipt->tcf_bindcnt - bind; 264 c.refcnt = ipt->tcf_refcnt - ref; 265 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 266 267 NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t); 268 NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index); 269 NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook); 270 NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c); 271 NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname); 272 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 273 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 274 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 275 NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm); 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 .capab = TCA_CAP_NONE, 290 .owner = THIS_MODULE, 291 .act = tcf_ipt, 292 .dump = tcf_ipt_dump, 293 .cleanup = tcf_ipt_cleanup, 294 .lookup = tcf_hash_search, 295 .init = tcf_ipt_init, 296 .walk = tcf_generic_walker 297 }; 298 299 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 300 MODULE_DESCRIPTION("Iptables target actions"); 301 MODULE_LICENSE("GPL"); 302 303 static int __init ipt_init_module(void) 304 { 305 return tcf_register_action(&act_ipt_ops); 306 } 307 308 static void __exit ipt_cleanup_module(void) 309 { 310 tcf_unregister_action(&act_ipt_ops); 311 } 312 313 module_init(ipt_init_module); 314 module_exit(ipt_cleanup_module); 315