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 int tcf_ipt_init(struct rtattr *rta, struct rtattr *est, 96 struct tc_action *a, int ovr, int bind) 97 { 98 struct rtattr *tb[TCA_IPT_MAX]; 99 struct tcf_ipt *ipt; 100 struct tcf_common *pc; 101 struct ipt_entry_target *td, *t; 102 char *tname; 103 int ret = 0, err; 104 u32 hook = 0; 105 u32 index = 0; 106 107 if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0) 108 return -EINVAL; 109 110 if (tb[TCA_IPT_HOOK-1] == NULL || 111 RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32)) 112 return -EINVAL; 113 if (tb[TCA_IPT_TARG-1] == NULL || 114 RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t)) 115 return -EINVAL; 116 td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]); 117 if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size) 118 return -EINVAL; 119 120 if (tb[TCA_IPT_INDEX-1] != NULL && 121 RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32)) 122 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]); 123 124 pc = tcf_hash_check(index, a, bind, &ipt_hash_info); 125 if (!pc) { 126 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind, 127 &ipt_idx_gen, &ipt_hash_info); 128 if (unlikely(!pc)) 129 return -ENOMEM; 130 ret = ACT_P_CREATED; 131 } else { 132 if (!ovr) { 133 tcf_ipt_release(to_ipt(pc), bind); 134 return -EEXIST; 135 } 136 } 137 ipt = to_ipt(pc); 138 139 hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]); 140 141 err = -ENOMEM; 142 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 143 if (unlikely(!tname)) 144 goto err1; 145 if (tb[TCA_IPT_TABLE - 1] == NULL || 146 rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ) 147 strcpy(tname, "mangle"); 148 149 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 150 if (unlikely(!t)) 151 goto err2; 152 153 if ((err = ipt_init_target(t, tname, hook)) < 0) 154 goto err3; 155 156 spin_lock_bh(&ipt->tcf_lock); 157 if (ret != ACT_P_CREATED) { 158 ipt_destroy_target(ipt->tcfi_t); 159 kfree(ipt->tcfi_tname); 160 kfree(ipt->tcfi_t); 161 } 162 ipt->tcfi_tname = tname; 163 ipt->tcfi_t = t; 164 ipt->tcfi_hook = hook; 165 spin_unlock_bh(&ipt->tcf_lock); 166 if (ret == ACT_P_CREATED) 167 tcf_hash_insert(pc, &ipt_hash_info); 168 return ret; 169 170 err3: 171 kfree(t); 172 err2: 173 kfree(tname); 174 err1: 175 kfree(pc); 176 return err; 177 } 178 179 static int tcf_ipt_cleanup(struct tc_action *a, int bind) 180 { 181 struct tcf_ipt *ipt = a->priv; 182 return tcf_ipt_release(ipt, bind); 183 } 184 185 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a, 186 struct tcf_result *res) 187 { 188 int ret = 0, result = 0; 189 struct tcf_ipt *ipt = a->priv; 190 191 if (skb_cloned(skb)) { 192 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 193 return TC_ACT_UNSPEC; 194 } 195 196 spin_lock(&ipt->tcf_lock); 197 198 ipt->tcf_tm.lastuse = jiffies; 199 ipt->tcf_bstats.bytes += skb->len; 200 ipt->tcf_bstats.packets++; 201 202 /* yes, we have to worry about both in and out dev 203 worry later - danger - this API seems to have changed 204 from earlier kernels */ 205 ret = ipt->tcfi_t->u.kernel.target->target(skb, skb->dev, NULL, 206 ipt->tcfi_hook, 207 ipt->tcfi_t->u.kernel.target, 208 ipt->tcfi_t->data); 209 switch (ret) { 210 case NF_ACCEPT: 211 result = TC_ACT_OK; 212 break; 213 case NF_DROP: 214 result = TC_ACT_SHOT; 215 ipt->tcf_qstats.drops++; 216 break; 217 case IPT_CONTINUE: 218 result = TC_ACT_PIPE; 219 break; 220 default: 221 if (net_ratelimit()) 222 printk("Bogus netfilter code %d assume ACCEPT\n", ret); 223 result = TC_POLICE_OK; 224 break; 225 } 226 spin_unlock(&ipt->tcf_lock); 227 return result; 228 229 } 230 231 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 232 { 233 unsigned char *b = skb_tail_pointer(skb); 234 struct tcf_ipt *ipt = a->priv; 235 struct ipt_entry_target *t; 236 struct tcf_t tm; 237 struct tc_cnt c; 238 239 /* for simple targets kernel size == user size 240 ** user name = target name 241 ** for foolproof you need to not assume this 242 */ 243 244 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 245 if (unlikely(!t)) 246 goto rtattr_failure; 247 248 c.bindcnt = ipt->tcf_bindcnt - bind; 249 c.refcnt = ipt->tcf_refcnt - ref; 250 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 251 252 RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t); 253 RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index); 254 RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook); 255 RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c); 256 RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, ipt->tcfi_tname); 257 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 258 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 259 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 260 RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm); 261 kfree(t); 262 return skb->len; 263 264 rtattr_failure: 265 nlmsg_trim(skb, b); 266 kfree(t); 267 return -1; 268 } 269 270 static struct tc_action_ops act_ipt_ops = { 271 .kind = "ipt", 272 .hinfo = &ipt_hash_info, 273 .type = TCA_ACT_IPT, 274 .capab = TCA_CAP_NONE, 275 .owner = THIS_MODULE, 276 .act = tcf_ipt, 277 .dump = tcf_ipt_dump, 278 .cleanup = tcf_ipt_cleanup, 279 .lookup = tcf_hash_search, 280 .init = tcf_ipt_init, 281 .walk = tcf_generic_walker 282 }; 283 284 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 285 MODULE_DESCRIPTION("Iptables target actions"); 286 MODULE_LICENSE("GPL"); 287 288 static int __init ipt_init_module(void) 289 { 290 return tcf_register_action(&act_ipt_ops); 291 } 292 293 static void __exit ipt_cleanup_module(void) 294 { 295 tcf_unregister_action(&act_ipt_ops); 296 } 297 298 module_init(ipt_init_module); 299 module_exit(ipt_cleanup_module); 300