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_target *target; 44 int ret = 0; 45 46 target = xt_request_find_target(AF_INET, t->u.user.name, 47 t->u.user.revision); 48 if (!target) 49 return -ENOENT; 50 51 t->u.kernel.target = target; 52 53 ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t), 54 table, hook, 0, 0); 55 if (ret) { 56 module_put(t->u.kernel.target->me); 57 return ret; 58 } 59 if (t->u.kernel.target->checkentry 60 && !t->u.kernel.target->checkentry(table, NULL, 61 t->u.kernel.target, t->data, 62 hook)) { 63 module_put(t->u.kernel.target->me); 64 ret = -EINVAL; 65 } 66 67 return ret; 68 } 69 70 static void ipt_destroy_target(struct ipt_entry_target *t) 71 { 72 if (t->u.kernel.target->destroy) 73 t->u.kernel.target->destroy(t->u.kernel.target, t->data); 74 module_put(t->u.kernel.target->me); 75 } 76 77 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 78 { 79 int ret = 0; 80 if (ipt) { 81 if (bind) 82 ipt->tcf_bindcnt--; 83 ipt->tcf_refcnt--; 84 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 85 ipt_destroy_target(ipt->tcfi_t); 86 kfree(ipt->tcfi_tname); 87 kfree(ipt->tcfi_t); 88 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 89 ret = ACT_P_DELETED; 90 } 91 } 92 return ret; 93 } 94 95 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 96 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 97 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 98 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 99 [TCA_IPT_TARG] = { .len = sizeof(struct ipt_entry_target) }, 100 }; 101 102 static int tcf_ipt_init(struct nlattr *nla, struct nlattr *est, 103 struct tc_action *a, int ovr, int bind) 104 { 105 struct nlattr *tb[TCA_IPT_MAX + 1]; 106 struct tcf_ipt *ipt; 107 struct tcf_common *pc; 108 struct ipt_entry_target *td, *t; 109 char *tname; 110 int ret = 0, err; 111 u32 hook = 0; 112 u32 index = 0; 113 114 if (nla == NULL) 115 return -EINVAL; 116 117 err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy); 118 if (err < 0) 119 return err; 120 121 if (tb[TCA_IPT_HOOK] == NULL) 122 return -EINVAL; 123 if (tb[TCA_IPT_TARG] == NULL) 124 return -EINVAL; 125 126 td = (struct ipt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 127 if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) 128 return -EINVAL; 129 130 if (tb[TCA_IPT_INDEX] != NULL) 131 index = nla_get_u32(tb[TCA_IPT_INDEX]); 132 133 pc = tcf_hash_check(index, a, bind, &ipt_hash_info); 134 if (!pc) { 135 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind, 136 &ipt_idx_gen, &ipt_hash_info); 137 if (unlikely(!pc)) 138 return -ENOMEM; 139 ret = ACT_P_CREATED; 140 } else { 141 if (!ovr) { 142 tcf_ipt_release(to_ipt(pc), bind); 143 return -EEXIST; 144 } 145 } 146 ipt = to_ipt(pc); 147 148 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 149 150 err = -ENOMEM; 151 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 152 if (unlikely(!tname)) 153 goto err1; 154 if (tb[TCA_IPT_TABLE] == NULL || 155 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 156 strcpy(tname, "mangle"); 157 158 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 159 if (unlikely(!t)) 160 goto err2; 161 162 if ((err = ipt_init_target(t, tname, hook)) < 0) 163 goto err3; 164 165 spin_lock_bh(&ipt->tcf_lock); 166 if (ret != ACT_P_CREATED) { 167 ipt_destroy_target(ipt->tcfi_t); 168 kfree(ipt->tcfi_tname); 169 kfree(ipt->tcfi_t); 170 } 171 ipt->tcfi_tname = tname; 172 ipt->tcfi_t = t; 173 ipt->tcfi_hook = hook; 174 spin_unlock_bh(&ipt->tcf_lock); 175 if (ret == ACT_P_CREATED) 176 tcf_hash_insert(pc, &ipt_hash_info); 177 return ret; 178 179 err3: 180 kfree(t); 181 err2: 182 kfree(tname); 183 err1: 184 kfree(pc); 185 return err; 186 } 187 188 static int tcf_ipt_cleanup(struct tc_action *a, int bind) 189 { 190 struct tcf_ipt *ipt = a->priv; 191 return tcf_ipt_release(ipt, bind); 192 } 193 194 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a, 195 struct tcf_result *res) 196 { 197 int ret = 0, result = 0; 198 struct tcf_ipt *ipt = a->priv; 199 200 if (skb_cloned(skb)) { 201 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 202 return TC_ACT_UNSPEC; 203 } 204 205 spin_lock(&ipt->tcf_lock); 206 207 ipt->tcf_tm.lastuse = jiffies; 208 ipt->tcf_bstats.bytes += skb->len; 209 ipt->tcf_bstats.packets++; 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 ret = ipt->tcfi_t->u.kernel.target->target(skb, skb->dev, NULL, 215 ipt->tcfi_hook, 216 ipt->tcfi_t->u.kernel.target, 217 ipt->tcfi_t->data); 218 switch (ret) { 219 case NF_ACCEPT: 220 result = TC_ACT_OK; 221 break; 222 case NF_DROP: 223 result = TC_ACT_SHOT; 224 ipt->tcf_qstats.drops++; 225 break; 226 case IPT_CONTINUE: 227 result = TC_ACT_PIPE; 228 break; 229 default: 230 if (net_ratelimit()) 231 printk("Bogus netfilter code %d assume ACCEPT\n", ret); 232 result = TC_POLICE_OK; 233 break; 234 } 235 spin_unlock(&ipt->tcf_lock); 236 return result; 237 238 } 239 240 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 241 { 242 unsigned char *b = skb_tail_pointer(skb); 243 struct tcf_ipt *ipt = a->priv; 244 struct ipt_entry_target *t; 245 struct tcf_t tm; 246 struct tc_cnt c; 247 248 /* for simple targets kernel size == user size 249 ** user name = target name 250 ** for foolproof you need to not assume this 251 */ 252 253 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 254 if (unlikely(!t)) 255 goto nla_put_failure; 256 257 c.bindcnt = ipt->tcf_bindcnt - bind; 258 c.refcnt = ipt->tcf_refcnt - ref; 259 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 260 261 NLA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t); 262 NLA_PUT_U32(skb, TCA_IPT_INDEX, ipt->tcf_index); 263 NLA_PUT_U32(skb, TCA_IPT_HOOK, ipt->tcfi_hook); 264 NLA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c); 265 NLA_PUT_STRING(skb, TCA_IPT_TABLE, ipt->tcfi_tname); 266 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 267 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 268 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 269 NLA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm); 270 kfree(t); 271 return skb->len; 272 273 nla_put_failure: 274 nlmsg_trim(skb, b); 275 kfree(t); 276 return -1; 277 } 278 279 static struct tc_action_ops act_ipt_ops = { 280 .kind = "ipt", 281 .hinfo = &ipt_hash_info, 282 .type = TCA_ACT_IPT, 283 .capab = TCA_CAP_NONE, 284 .owner = THIS_MODULE, 285 .act = tcf_ipt, 286 .dump = tcf_ipt_dump, 287 .cleanup = tcf_ipt_cleanup, 288 .lookup = tcf_hash_search, 289 .init = tcf_ipt_init, 290 .walk = tcf_generic_walker 291 }; 292 293 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 294 MODULE_DESCRIPTION("Iptables target actions"); 295 MODULE_LICENSE("GPL"); 296 297 static int __init ipt_init_module(void) 298 { 299 return tcf_register_action(&act_ipt_ops); 300 } 301 302 static void __exit ipt_cleanup_module(void) 303 { 304 tcf_unregister_action(&act_ipt_ops); 305 } 306 307 module_init(ipt_init_module); 308 module_exit(ipt_cleanup_module); 309