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/config.h> 18 #include <linux/types.h> 19 #include <linux/kernel.h> 20 #include <linux/sched.h> 21 #include <linux/string.h> 22 #include <linux/mm.h> 23 #include <linux/socket.h> 24 #include <linux/sockios.h> 25 #include <linux/in.h> 26 #include <linux/errno.h> 27 #include <linux/interrupt.h> 28 #include <linux/netdevice.h> 29 #include <linux/skbuff.h> 30 #include <linux/rtnetlink.h> 31 #include <linux/module.h> 32 #include <linux/init.h> 33 #include <linux/proc_fs.h> 34 #include <linux/kmod.h> 35 #include <net/sock.h> 36 #include <net/pkt_sched.h> 37 #include <linux/tc_act/tc_ipt.h> 38 #include <net/tc_act/tc_ipt.h> 39 40 #include <linux/netfilter_ipv4/ip_tables.h> 41 42 /* use generic hash table */ 43 #define MY_TAB_SIZE 16 44 #define MY_TAB_MASK 15 45 46 static u32 idx_gen; 47 static struct tcf_ipt *tcf_ipt_ht[MY_TAB_SIZE]; 48 /* ipt hash table lock */ 49 static DEFINE_RWLOCK(ipt_lock); 50 51 /* ovewrride the defaults */ 52 #define tcf_st tcf_ipt 53 #define tcf_t_lock ipt_lock 54 #define tcf_ht tcf_ipt_ht 55 56 #define CONFIG_NET_ACT_INIT 57 #include <net/pkt_act.h> 58 59 static int 60 ipt_init_target(struct ipt_entry_target *t, char *table, unsigned int hook) 61 { 62 struct ipt_target *target; 63 int ret = 0; 64 65 target = ipt_find_target(t->u.user.name, t->u.user.revision); 66 if (!target) 67 return -ENOENT; 68 69 DPRINTK("ipt_init_target: found %s\n", target->name); 70 t->u.kernel.target = target; 71 72 if (t->u.kernel.target->checkentry 73 && !t->u.kernel.target->checkentry(table, NULL, t->data, 74 t->u.target_size - sizeof(*t), 75 hook)) { 76 DPRINTK("ipt_init_target: check failed for `%s'.\n", 77 t->u.kernel.target->name); 78 module_put(t->u.kernel.target->me); 79 ret = -EINVAL; 80 } 81 82 return ret; 83 } 84 85 static void 86 ipt_destroy_target(struct ipt_entry_target *t) 87 { 88 if (t->u.kernel.target->destroy) 89 t->u.kernel.target->destroy(t->data, 90 t->u.target_size - sizeof(*t)); 91 module_put(t->u.kernel.target->me); 92 } 93 94 static int 95 tcf_ipt_release(struct tcf_ipt *p, int bind) 96 { 97 int ret = 0; 98 if (p) { 99 if (bind) 100 p->bindcnt--; 101 p->refcnt--; 102 if (p->bindcnt <= 0 && p->refcnt <= 0) { 103 ipt_destroy_target(p->t); 104 kfree(p->tname); 105 kfree(p->t); 106 tcf_hash_destroy(p); 107 ret = ACT_P_DELETED; 108 } 109 } 110 return ret; 111 } 112 113 static int 114 tcf_ipt_init(struct rtattr *rta, struct rtattr *est, struct tc_action *a, 115 int ovr, int bind) 116 { 117 struct rtattr *tb[TCA_IPT_MAX]; 118 struct tcf_ipt *p; 119 struct ipt_entry_target *td, *t; 120 char *tname; 121 int ret = 0, err; 122 u32 hook = 0; 123 u32 index = 0; 124 125 if (rta == NULL || rtattr_parse_nested(tb, TCA_IPT_MAX, rta) < 0) 126 return -EINVAL; 127 128 if (tb[TCA_IPT_HOOK-1] == NULL || 129 RTA_PAYLOAD(tb[TCA_IPT_HOOK-1]) < sizeof(u32)) 130 return -EINVAL; 131 if (tb[TCA_IPT_TARG-1] == NULL || 132 RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < sizeof(*t)) 133 return -EINVAL; 134 td = (struct ipt_entry_target *)RTA_DATA(tb[TCA_IPT_TARG-1]); 135 if (RTA_PAYLOAD(tb[TCA_IPT_TARG-1]) < td->u.target_size) 136 return -EINVAL; 137 138 if (tb[TCA_IPT_INDEX-1] != NULL && 139 RTA_PAYLOAD(tb[TCA_IPT_INDEX-1]) >= sizeof(u32)) 140 index = *(u32 *)RTA_DATA(tb[TCA_IPT_INDEX-1]); 141 142 p = tcf_hash_check(index, a, ovr, bind); 143 if (p == NULL) { 144 p = tcf_hash_create(index, est, a, sizeof(*p), ovr, bind); 145 if (p == NULL) 146 return -ENOMEM; 147 ret = ACT_P_CREATED; 148 } else { 149 if (!ovr) { 150 tcf_ipt_release(p, bind); 151 return -EEXIST; 152 } 153 } 154 155 hook = *(u32 *)RTA_DATA(tb[TCA_IPT_HOOK-1]); 156 157 err = -ENOMEM; 158 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 159 if (tname == NULL) 160 goto err1; 161 if (tb[TCA_IPT_TABLE - 1] == NULL || 162 rtattr_strlcpy(tname, tb[TCA_IPT_TABLE-1], IFNAMSIZ) >= IFNAMSIZ) 163 strcpy(tname, "mangle"); 164 165 t = kmalloc(td->u.target_size, GFP_KERNEL); 166 if (t == NULL) 167 goto err2; 168 memcpy(t, td, td->u.target_size); 169 170 if ((err = ipt_init_target(t, tname, hook)) < 0) 171 goto err3; 172 173 spin_lock_bh(&p->lock); 174 if (ret != ACT_P_CREATED) { 175 ipt_destroy_target(p->t); 176 kfree(p->tname); 177 kfree(p->t); 178 } 179 p->tname = tname; 180 p->t = t; 181 p->hook = hook; 182 spin_unlock_bh(&p->lock); 183 if (ret == ACT_P_CREATED) 184 tcf_hash_insert(p); 185 return ret; 186 187 err3: 188 kfree(t); 189 err2: 190 kfree(tname); 191 err1: 192 kfree(p); 193 return err; 194 } 195 196 static int 197 tcf_ipt_cleanup(struct tc_action *a, int bind) 198 { 199 struct tcf_ipt *p = PRIV(a, ipt); 200 return tcf_ipt_release(p, bind); 201 } 202 203 static int 204 tcf_ipt(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res) 205 { 206 int ret = 0, result = 0; 207 struct tcf_ipt *p = PRIV(a, ipt); 208 209 if (skb_cloned(skb)) { 210 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 211 return TC_ACT_UNSPEC; 212 } 213 214 spin_lock(&p->lock); 215 216 p->tm.lastuse = jiffies; 217 p->bstats.bytes += skb->len; 218 p->bstats.packets++; 219 220 /* yes, we have to worry about both in and out dev 221 worry later - danger - this API seems to have changed 222 from earlier kernels */ 223 224 /* iptables targets take a double skb pointer in case the skb 225 * needs to be replaced. We don't own the skb, so this must not 226 * happen. The pskb_expand_head above should make sure of this */ 227 ret = p->t->u.kernel.target->target(&skb, skb->dev, NULL, 228 p->hook, p->t->data, NULL); 229 switch (ret) { 230 case NF_ACCEPT: 231 result = TC_ACT_OK; 232 break; 233 case NF_DROP: 234 result = TC_ACT_SHOT; 235 p->qstats.drops++; 236 break; 237 case IPT_CONTINUE: 238 result = TC_ACT_PIPE; 239 break; 240 default: 241 if (net_ratelimit()) 242 printk("Bogus netfilter code %d assume ACCEPT\n", ret); 243 result = TC_POLICE_OK; 244 break; 245 } 246 spin_unlock(&p->lock); 247 return result; 248 249 } 250 251 static int 252 tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 253 { 254 struct ipt_entry_target *t; 255 struct tcf_t tm; 256 struct tc_cnt c; 257 unsigned char *b = skb->tail; 258 struct tcf_ipt *p = PRIV(a, ipt); 259 260 /* for simple targets kernel size == user size 261 ** user name = target name 262 ** for foolproof you need to not assume this 263 */ 264 265 t = kmalloc(p->t->u.user.target_size, GFP_ATOMIC); 266 if (t == NULL) 267 goto rtattr_failure; 268 269 c.bindcnt = p->bindcnt - bind; 270 c.refcnt = p->refcnt - ref; 271 memcpy(t, p->t, p->t->u.user.target_size); 272 strcpy(t->u.user.name, p->t->u.kernel.target->name); 273 274 DPRINTK("\ttcf_ipt_dump tablename %s length %d\n", p->tname, 275 strlen(p->tname)); 276 DPRINTK("\tdump target name %s size %d size user %d " 277 "data[0] %x data[1] %x\n", p->t->u.kernel.target->name, 278 p->t->u.target_size, p->t->u.user.target_size, 279 p->t->data[0], p->t->data[1]); 280 RTA_PUT(skb, TCA_IPT_TARG, p->t->u.user.target_size, t); 281 RTA_PUT(skb, TCA_IPT_INDEX, 4, &p->index); 282 RTA_PUT(skb, TCA_IPT_HOOK, 4, &p->hook); 283 RTA_PUT(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c); 284 RTA_PUT(skb, TCA_IPT_TABLE, IFNAMSIZ, p->tname); 285 tm.install = jiffies_to_clock_t(jiffies - p->tm.install); 286 tm.lastuse = jiffies_to_clock_t(jiffies - p->tm.lastuse); 287 tm.expires = jiffies_to_clock_t(p->tm.expires); 288 RTA_PUT(skb, TCA_IPT_TM, sizeof (tm), &tm); 289 kfree(t); 290 return skb->len; 291 292 rtattr_failure: 293 skb_trim(skb, b - skb->data); 294 kfree(t); 295 return -1; 296 } 297 298 static struct tc_action_ops act_ipt_ops = { 299 .kind = "ipt", 300 .type = TCA_ACT_IPT, 301 .capab = TCA_CAP_NONE, 302 .owner = THIS_MODULE, 303 .act = tcf_ipt, 304 .dump = tcf_ipt_dump, 305 .cleanup = tcf_ipt_cleanup, 306 .lookup = tcf_hash_search, 307 .init = tcf_ipt_init, 308 .walk = tcf_generic_walker 309 }; 310 311 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 312 MODULE_DESCRIPTION("Iptables target actions"); 313 MODULE_LICENSE("GPL"); 314 315 static int __init 316 ipt_init_module(void) 317 { 318 return tcf_register_action(&act_ipt_ops); 319 } 320 321 static void __exit 322 ipt_cleanup_module(void) 323 { 324 tcf_unregister_action(&act_ipt_ops); 325 } 326 327 module_init(ipt_init_module); 328 module_exit(ipt_cleanup_module); 329