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/sched.h> 20 #include <linux/string.h> 21 #include <linux/mm.h> 22 #include <linux/socket.h> 23 #include <linux/sockios.h> 24 #include <linux/in.h> 25 #include <linux/errno.h> 26 #include <linux/interrupt.h> 27 #include <linux/netdevice.h> 28 #include <linux/skbuff.h> 29 #include <linux/rtnetlink.h> 30 #include <linux/module.h> 31 #include <linux/init.h> 32 #include <linux/proc_fs.h> 33 #include <linux/kmod.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 ipt_target *target; 56 int ret = 0; 57 58 target = xt_find_target(AF_INET, t->u.user.name, t->u.user.revision); 59 if (!target) 60 return -ENOENT; 61 62 t->u.kernel.target = target; 63 64 ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t), 65 table, hook, 0, 0); 66 if (ret) 67 return ret; 68 69 if (t->u.kernel.target->checkentry 70 && !t->u.kernel.target->checkentry(table, NULL, 71 t->u.kernel.target, t->data, 72 hook)) { 73 module_put(t->u.kernel.target->me); 74 ret = -EINVAL; 75 } 76 77 return ret; 78 } 79 80 static void ipt_destroy_target(struct ipt_entry_target *t) 81 { 82 if (t->u.kernel.target->destroy) 83 t->u.kernel.target->destroy(t->u.kernel.target, t->data); 84 module_put(t->u.kernel.target->me); 85 } 86 87 static int tcf_ipt_release(struct tcf_ipt *ipt, int bind) 88 { 89 int ret = 0; 90 if (ipt) { 91 if (bind) 92 ipt->tcf_bindcnt--; 93 ipt->tcf_refcnt--; 94 if (ipt->tcf_bindcnt <= 0 && ipt->tcf_refcnt <= 0) { 95 ipt_destroy_target(ipt->tcfi_t); 96 kfree(ipt->tcfi_tname); 97 kfree(ipt->tcfi_t); 98 tcf_hash_destroy(&ipt->common, &ipt_hash_info); 99 ret = ACT_P_DELETED; 100 } 101 } 102 return ret; 103 } 104 105 static int tcf_ipt_init(struct rtattr *rta, struct rtattr *est, 106 struct tc_action *a, int ovr, int bind) 107 { 108 struct rtattr *tb[TCA_IPT_MAX]; 109 struct tcf_ipt *ipt; 110 struct tcf_common *pc; 111 struct ipt_entry_target *td, *t; 112 char *tname; 113 int ret = 0, err; 114 u32 hook = 0; 115 u32 index = 0; 116 117 if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0) 118 return -EINVAL; 119 120 if (tb[TCA_IPT_HOOK-1] == NULL || 121 RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32)) 122 return -EINVAL; 123 if (tb[TCA_IPT_TARG-1] == NULL || 124 RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t)) 125 return -EINVAL; 126 td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]); 127 if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size) 128 return -EINVAL; 129 130 if (tb[TCA_IPT_INDEX-1] != NULL && 131 RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32)) 132 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]); 133 134 pc = tcf_hash_check(index, a, bind, &ipt_hash_info); 135 if (!pc) { 136 pc = tcf_hash_create(index, est, a, sizeof(*ipt), bind, 137 &ipt_idx_gen, &ipt_hash_info); 138 if (unlikely(!pc)) 139 return -ENOMEM; 140 ret = ACT_P_CREATED; 141 } else { 142 if (!ovr) { 143 tcf_ipt_release(to_ipt(pc), bind); 144 return -EEXIST; 145 } 146 } 147 ipt = to_ipt(pc); 148 149 hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]); 150 151 err = -ENOMEM; 152 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 153 if (unlikely(!tname)) 154 goto err1; 155 if (tb[TCA_IPT_TABLE - 1] == NULL || 156 rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ) 157 strcpy(tname, "mangle"); 158 159 t = kmalloc(td->u.target_size, GFP_KERNEL); 160 if (unlikely(!t)) 161 goto err2; 162 memcpy(t, td, td->u.target_size); 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; 201 202 if (skb_cloned(skb)) { 203 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 204 return TC_ACT_UNSPEC; 205 } 206 207 spin_lock(&ipt->tcf_lock); 208 209 ipt->tcf_tm.lastuse = jiffies; 210 ipt->tcf_bstats.bytes += skb->len; 211 ipt->tcf_bstats.packets++; 212 213 /* yes, we have to worry about both in and out dev 214 worry later - danger - this API seems to have changed 215 from earlier kernels */ 216 217 /* iptables targets take a double skb pointer in case the skb 218 * needs to be replaced. We don't own the skb, so this must not 219 * happen. The pskb_expand_head above should make sure of this */ 220 ret = ipt->tcfi_t->u.kernel.target->target(&skb, skb->dev, NULL, 221 ipt->tcfi_hook, 222 ipt->tcfi_t->u.kernel.target, 223 ipt->tcfi_t->data); 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; 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 = kmalloc(ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 260 if (unlikely(!t)) 261 goto rtattr_failure; 262 263 c.bindcnt = ipt->tcf_bindcnt - bind; 264 c.refcnt = ipt->tcf_refcnt - ref; 265 memcpy(t, ipt->tcfi_t, ipt->tcfi_t->u.user.target_size); 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 skb_trim(skb, b - skb->data); 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