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 <asm/uaccess.h> 15 #include <asm/system.h> 16 #include <asm/bitops.h> 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/string.h> 20 #include <linux/mm.h> 21 #include <linux/socket.h> 22 #include <linux/sockios.h> 23 #include <linux/in.h> 24 #include <linux/errno.h> 25 #include <linux/interrupt.h> 26 #include <linux/netdevice.h> 27 #include <linux/skbuff.h> 28 #include <linux/rtnetlink.h> 29 #include <linux/module.h> 30 #include <linux/init.h> 31 #include <linux/proc_fs.h> 32 #include <linux/kmod.h> 33 #include <net/netlink.h> 34 #include <net/sock.h> 35 #include <net/pkt_sched.h> 36 #include <linux/tc_act/tc_ipt.h> 37 #include <net/tc_act/tc_ipt.h> 38 39 #include <linux/netfilter_ipv4/ip_tables.h> 40 41 42 #define IPT_TAB_MASK 15 43 static struct tcf_common *tcf_ipt_ht[IPT_TAB_MASK + 1]; 44 static u32 ipt_idx_gen; 45 static DEFINE_RWLOCK(ipt_lock); 46 47 static struct tcf_hashinfo ipt_hash_info = { 48 .htab = tcf_ipt_ht, 49 .hmask = IPT_TAB_MASK, 50 .lock = &ipt_lock, 51 }; 52 53 static int ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook) 54 { 55 struct xt_target *target; 56 int ret = 0; 57 58 target = xt_request_find_target(AF_INET, t->u.user.name, 59 t->u.user.revision); 60 if (!target) 61 return -ENOENT; 62 63 t->u.kernel.target = target; 64 65 ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t), 66 table, hook, 0, 0); 67 if (ret) { 68 module_put(t->u.kernel.target->me); 69 return ret; 70 } 71 if (t->u.kernel.target->checkentry 72 && !t->u.kernel.target->checkentry(table, NULL, 73 t->u.kernel.target, t->data, 74 hook)) { 75 module_put(t->u.kernel.target->me); 76 ret = -EINVAL; 77 } 78 79 return ret; 80 } 81 82 static void ipt_destroy_target(struct ipt_entry_target *t) 83 { 84 if (t->u.kernel.target->destroy) 85 t->u.kernel.target->destroy(t->u.kernel.target, t->data); 86 module_put(t->u.kernel.target->me); 87 } 88 89 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 90 { 91 int ret = 0; 92 if (ipt) { 93 if (bind) 94 ipt->tcf_bindcnt--; 95 ipt->tcf_refcnt--; 96 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 97 ipt_destroy_target(ipt->tcfi_t); 98 kfree(ipt->tcfi_tname); 99 kfree(ipt->tcfi_t); 100 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 101 ret = ACT_P_DELETED; 102 } 103 } 104 return ret; 105 } 106 107 static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est, 108 struct tc_action *a, int ovr, int bind) 109 { 110 struct rtattr *tb[TCA_IPT_MAX]; 111 struct tcf_ipt *ipt; 112 struct tcf_common *pc; 113 struct ipt_entry_target *td, *t; 114 char *tname; 115 int ret = 0, err; 116 u32 hook = 0; 117 u32 index = 0; 118 119 if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0) 120 return -EINVAL; 121 122 if (tb[TCA_IPT_HOOK-1] == NULL || 123 RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32)) 124 return -EINVAL; 125 if (tb[TCA_IPT_TARG-1] == NULL || 126 RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t)) 127 return -EINVAL; 128 td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]); 129 if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size) 130 return -EINVAL; 131 132 if (tb[TCA_IPT_INDEX-1] != NULL && 133 RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32)) 134 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]); 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 (unlikely(!pc)) 141 return -ENOMEM; 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 = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]); 152 153 err = -ENOMEM; 154 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 155 if (unlikely(!tname)) 156 goto err1; 157 if (tb[TCA_IPT_TABLE - 1] == NULL || 158 rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], 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 if ((err = ipt_init_target(t, tname, hook)) < 0) 166 goto err3; 167 168 spin_lock_bh(&ipt->tcf_lock); 169 if (ret != ACT_P_CREATED) { 170 ipt_destroy_target(ipt->tcfi_t); 171 kfree(ipt->tcfi_tname); 172 kfree(ipt->tcfi_t); 173 } 174 ipt->tcfi_tname = tname; 175 ipt->tcfi_t = t; 176 ipt->tcfi_hook = hook; 177 spin_unlock_bh(&ipt->tcf_lock); 178 if (ret == ACT_P_CREATED) 179 tcf_hash_insert(pc, &ipt_hash_info); 180 return ret; 181 182 err3: 183 kfree(t); 184 err2: 185 kfree(tname); 186 err1: 187 kfree(pc); 188 return err; 189 } 190 191 static int tcf_ipt_cleanup(struct tc_action *a, int bind) 192 { 193 struct tcf_ipt *ipt = a->priv; 194 return tcf_ipt_release(ipt, bind); 195 } 196 197 static int tcf_ipt(struct sk_buff *skb, struct tc_action *a, 198 struct tcf_result *res) 199 { 200 int ret = 0, result = 0; 201 struct tcf_ipt *ipt = a->priv; 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 += skb->len; 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 */ 217 218 /* iptables targets take a double skb pointer in case the skb 219 * needs to be replaced. We don't own the skb, so this must not 220 * happen. The pskb_expand_head above should make sure of this */ 221 ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL, 222 ipt->tcfi_hook, 223 ipt->tcfi_t->u.kernel.target, 224 ipt->tcfi_t->data); 225 switch (ret) { 226 case NF_ACCEPT: 227 result = TC_ACT_OK; 228 break; 229 case NF_DROP: 230 result = TC_ACT_SHOT; 231 ipt->tcf_qstats.drops++; 232 break; 233 case IPT_CONTINUE: 234 result = TC_ACT_PIPE; 235 break; 236 default: 237 if (net_ratelimit()) 238 printk("Bogus netfilter code %d assume ACCEPT\n", ret); 239 result = TC_POLICE_OK; 240 break; 241 } 242 spin_unlock(&ipt->tcf_lock); 243 return result; 244 245 } 246 247 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 248 { 249 unsigned char *b = skb_tail_pointer(skb); 250 struct tcf_ipt *ipt = a->priv; 251 struct ipt_entry_target *t; 252 struct tcf_t tm; 253 struct tc_cnt c; 254 255 /* for simple targets kernel size == user size 256 ** user name = target name 257 ** for foolproof you need to not assume this 258 */ 259 260 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 261 if (unlikely(!t)) 262 goto rtattr_failure; 263 264 c.bindcnt = ipt->tcf_bindcnt - bind; 265 c.refcnt = ipt->tcf_refcnt - ref; 266 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 267 268 RTA_PUT(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t); 269 RTA_PUT(skb, TCA_IPT_INDEX, 4, &ipt->tcf_index); 270 RTA_PUT(skb, TCA_IPT_HOOK, 4, &ipt->tcfi_hook); 271 RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c); 272 RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, ipt->tcfi_tname); 273 tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); 274 tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); 275 tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); 276 RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm); 277 kfree(t); 278 return skb->len; 279 280 rtattr_failure: 281 nlmsg_trim(skb, b); 282 kfree(t); 283 return -1; 284 } 285 286 static struct tc_action_ops act_ipt_ops = { 287 .kind = "ipt", 288 .hinfo = &ipt_hash_info, 289 .type = TCA_ACT_IPT, 290 .capab = TCA_CAP_NONE, 291 .owner = THIS_MODULE, 292 .act = tcf_ipt, 293 .dump = tcf_ipt_dump, 294 .cleanup = tcf_ipt_cleanup, 295 .lookup = tcf_hash_search, 296 .init = tcf_ipt_init, 297 .walk = tcf_generic_walker 298 }; 299 300 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 301 MODULE_DESCRIPTION("Iptables target actions"); 302 MODULE_LICENSE("GPL"); 303 304 static int __init ipt_init_module(void) 305 { 306 return tcf_register_action(&act_ipt_ops); 307 } 308 309 static void __exit ipt_cleanup_module(void) 310 { 311 tcf_unregister_action(&act_ipt_ops); 312 } 313 314 module_init(ipt_init_module); 315 module_exit(ipt_cleanup_module); 316