| 1 | /* |
| 2 | * net/sched/act_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 (2002-13) |
| 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 <linux/slab.h> |
| 23 | #include <net/netlink.h> |
| 24 | #include <net/pkt_sched.h> |
| 25 | #include <linux/tc_act/tc_ipt.h> |
| 26 | #include <net/tc_act/tc_ipt.h> |
| 27 | |
| 28 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 29 | |
| 30 | |
| 31 | #define IPT_TAB_MASK 15 |
| 32 | |
| 33 | static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook) |
| 34 | { |
| 35 | struct xt_tgchk_param par; |
| 36 | struct xt_target *target; |
| 37 | struct ipt_entry e = {}; |
| 38 | int ret = 0; |
| 39 | |
| 40 | target = xt_request_find_target(AF_INET, t->u.user.name, |
| 41 | t->u.user.revision); |
| 42 | if (IS_ERR(target)) |
| 43 | return PTR_ERR(target); |
| 44 | |
| 45 | t->u.kernel.target = target; |
| 46 | memset(&par, 0, sizeof(par)); |
| 47 | par.table = table; |
| 48 | par.entryinfo = &e; |
| 49 | par.target = target; |
| 50 | par.targinfo = t->data; |
| 51 | par.hook_mask = hook; |
| 52 | par.family = NFPROTO_IPV4; |
| 53 | |
| 54 | ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); |
| 55 | if (ret < 0) { |
| 56 | module_put(t->u.kernel.target->me); |
| 57 | return ret; |
| 58 | } |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | static void ipt_destroy_target(struct xt_entry_target *t) |
| 63 | { |
| 64 | struct xt_tgdtor_param par = { |
| 65 | .target = t->u.kernel.target, |
| 66 | .targinfo = t->data, |
| 67 | }; |
| 68 | if (par.target->destroy != NULL) |
| 69 | par.target->destroy(&par); |
| 70 | module_put(par.target->me); |
| 71 | } |
| 72 | |
| 73 | static void tcf_ipt_release(struct tc_action *a, int bind) |
| 74 | { |
| 75 | struct tcf_ipt *ipt = to_ipt(a); |
| 76 | ipt_destroy_target(ipt->tcfi_t); |
| 77 | kfree(ipt->tcfi_tname); |
| 78 | kfree(ipt->tcfi_t); |
| 79 | } |
| 80 | |
| 81 | static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { |
| 82 | [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, |
| 83 | [TCA_IPT_HOOK] = { .type = NLA_U32 }, |
| 84 | [TCA_IPT_INDEX] = { .type = NLA_U32 }, |
| 85 | [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, |
| 86 | }; |
| 87 | |
| 88 | static int tcf_ipt_init(struct net *net, struct nlattr *nla, struct nlattr *est, |
| 89 | struct tc_action *a, int ovr, int bind) |
| 90 | { |
| 91 | struct nlattr *tb[TCA_IPT_MAX + 1]; |
| 92 | struct tcf_ipt *ipt; |
| 93 | struct xt_entry_target *td, *t; |
| 94 | char *tname; |
| 95 | int ret = 0, err; |
| 96 | u32 hook = 0; |
| 97 | u32 index = 0; |
| 98 | |
| 99 | if (nla == NULL) |
| 100 | return -EINVAL; |
| 101 | |
| 102 | err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy); |
| 103 | if (err < 0) |
| 104 | return err; |
| 105 | |
| 106 | if (tb[TCA_IPT_HOOK] == NULL) |
| 107 | return -EINVAL; |
| 108 | if (tb[TCA_IPT_TARG] == NULL) |
| 109 | return -EINVAL; |
| 110 | |
| 111 | td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); |
| 112 | if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) |
| 113 | return -EINVAL; |
| 114 | |
| 115 | if (tb[TCA_IPT_INDEX] != NULL) |
| 116 | index = nla_get_u32(tb[TCA_IPT_INDEX]); |
| 117 | |
| 118 | if (!tcf_hash_check(index, a, bind) ) { |
| 119 | ret = tcf_hash_create(index, est, a, sizeof(*ipt), bind, false); |
| 120 | if (ret) |
| 121 | return ret; |
| 122 | ret = ACT_P_CREATED; |
| 123 | } else { |
| 124 | if (bind)/* dont override defaults */ |
| 125 | return 0; |
| 126 | tcf_hash_release(a, bind); |
| 127 | |
| 128 | if (!ovr) |
| 129 | return -EEXIST; |
| 130 | } |
| 131 | ipt = to_ipt(a); |
| 132 | |
| 133 | hook = nla_get_u32(tb[TCA_IPT_HOOK]); |
| 134 | |
| 135 | err = -ENOMEM; |
| 136 | tname = kmalloc(IFNAMSIZ, GFP_KERNEL); |
| 137 | if (unlikely(!tname)) |
| 138 | goto err1; |
| 139 | if (tb[TCA_IPT_TABLE] == NULL || |
| 140 | nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) |
| 141 | strcpy(tname, "mangle"); |
| 142 | |
| 143 | t = kmemdup(td, td->u.target_size, GFP_KERNEL); |
| 144 | if (unlikely(!t)) |
| 145 | goto err2; |
| 146 | |
| 147 | err = ipt_init_target(t, tname, hook); |
| 148 | if (err < 0) |
| 149 | goto err3; |
| 150 | |
| 151 | spin_lock_bh(&ipt->tcf_lock); |
| 152 | if (ret != ACT_P_CREATED) { |
| 153 | ipt_destroy_target(ipt->tcfi_t); |
| 154 | kfree(ipt->tcfi_tname); |
| 155 | kfree(ipt->tcfi_t); |
| 156 | } |
| 157 | ipt->tcfi_tname = tname; |
| 158 | ipt->tcfi_t = t; |
| 159 | ipt->tcfi_hook = hook; |
| 160 | spin_unlock_bh(&ipt->tcf_lock); |
| 161 | if (ret == ACT_P_CREATED) |
| 162 | tcf_hash_insert(a); |
| 163 | return ret; |
| 164 | |
| 165 | err3: |
| 166 | kfree(t); |
| 167 | err2: |
| 168 | kfree(tname); |
| 169 | err1: |
| 170 | if (ret == ACT_P_CREATED) |
| 171 | tcf_hash_cleanup(a, est); |
| 172 | return err; |
| 173 | } |
| 174 | |
| 175 | static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a, |
| 176 | struct tcf_result *res) |
| 177 | { |
| 178 | int ret = 0, result = 0; |
| 179 | struct tcf_ipt *ipt = a->priv; |
| 180 | struct xt_action_param par; |
| 181 | |
| 182 | if (skb_unclone(skb, GFP_ATOMIC)) |
| 183 | return TC_ACT_UNSPEC; |
| 184 | |
| 185 | spin_lock(&ipt->tcf_lock); |
| 186 | |
| 187 | ipt->tcf_tm.lastuse = jiffies; |
| 188 | bstats_update(&ipt->tcf_bstats, skb); |
| 189 | |
| 190 | /* yes, we have to worry about both in and out dev |
| 191 | * worry later - danger - this API seems to have changed |
| 192 | * from earlier kernels |
| 193 | */ |
| 194 | par.net = dev_net(skb->dev); |
| 195 | par.in = skb->dev; |
| 196 | par.out = NULL; |
| 197 | par.hooknum = ipt->tcfi_hook; |
| 198 | par.target = ipt->tcfi_t->u.kernel.target; |
| 199 | par.targinfo = ipt->tcfi_t->data; |
| 200 | ret = par.target->target(skb, &par); |
| 201 | |
| 202 | switch (ret) { |
| 203 | case NF_ACCEPT: |
| 204 | result = TC_ACT_OK; |
| 205 | break; |
| 206 | case NF_DROP: |
| 207 | result = TC_ACT_SHOT; |
| 208 | ipt->tcf_qstats.drops++; |
| 209 | break; |
| 210 | case XT_CONTINUE: |
| 211 | result = TC_ACT_PIPE; |
| 212 | break; |
| 213 | default: |
| 214 | net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", |
| 215 | ret); |
| 216 | result = TC_POLICE_OK; |
| 217 | break; |
| 218 | } |
| 219 | spin_unlock(&ipt->tcf_lock); |
| 220 | return result; |
| 221 | |
| 222 | } |
| 223 | |
| 224 | static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) |
| 225 | { |
| 226 | unsigned char *b = skb_tail_pointer(skb); |
| 227 | struct tcf_ipt *ipt = a->priv; |
| 228 | struct xt_entry_target *t; |
| 229 | struct tcf_t tm; |
| 230 | struct tc_cnt c; |
| 231 | |
| 232 | /* for simple targets kernel size == user size |
| 233 | * user name = target name |
| 234 | * for foolproof you need to not assume this |
| 235 | */ |
| 236 | |
| 237 | t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); |
| 238 | if (unlikely(!t)) |
| 239 | goto nla_put_failure; |
| 240 | |
| 241 | c.bindcnt = ipt->tcf_bindcnt - bind; |
| 242 | c.refcnt = ipt->tcf_refcnt - ref; |
| 243 | strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); |
| 244 | |
| 245 | if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || |
| 246 | nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || |
| 247 | nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || |
| 248 | nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || |
| 249 | nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) |
| 250 | goto nla_put_failure; |
| 251 | tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install); |
| 252 | tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse); |
| 253 | tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires); |
| 254 | if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm)) |
| 255 | goto nla_put_failure; |
| 256 | kfree(t); |
| 257 | return skb->len; |
| 258 | |
| 259 | nla_put_failure: |
| 260 | nlmsg_trim(skb, b); |
| 261 | kfree(t); |
| 262 | return -1; |
| 263 | } |
| 264 | |
| 265 | static struct tc_action_ops act_ipt_ops = { |
| 266 | .kind = "ipt", |
| 267 | .type = TCA_ACT_IPT, |
| 268 | .owner = THIS_MODULE, |
| 269 | .act = tcf_ipt, |
| 270 | .dump = tcf_ipt_dump, |
| 271 | .cleanup = tcf_ipt_release, |
| 272 | .init = tcf_ipt_init, |
| 273 | }; |
| 274 | |
| 275 | static struct tc_action_ops act_xt_ops = { |
| 276 | .kind = "xt", |
| 277 | .type = TCA_ACT_XT, |
| 278 | .owner = THIS_MODULE, |
| 279 | .act = tcf_ipt, |
| 280 | .dump = tcf_ipt_dump, |
| 281 | .cleanup = tcf_ipt_release, |
| 282 | .init = tcf_ipt_init, |
| 283 | }; |
| 284 | |
| 285 | MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); |
| 286 | MODULE_DESCRIPTION("Iptables target actions"); |
| 287 | MODULE_LICENSE("GPL"); |
| 288 | MODULE_ALIAS("act_xt"); |
| 289 | |
| 290 | static int __init ipt_init_module(void) |
| 291 | { |
| 292 | int ret1, ret2; |
| 293 | |
| 294 | ret1 = tcf_register_action(&act_xt_ops, IPT_TAB_MASK); |
| 295 | if (ret1 < 0) |
| 296 | printk("Failed to load xt action\n"); |
| 297 | ret2 = tcf_register_action(&act_ipt_ops, IPT_TAB_MASK); |
| 298 | if (ret2 < 0) |
| 299 | printk("Failed to load ipt action\n"); |
| 300 | |
| 301 | if (ret1 < 0 && ret2 < 0) { |
| 302 | return ret1; |
| 303 | } else |
| 304 | return 0; |
| 305 | } |
| 306 | |
| 307 | static void __exit ipt_cleanup_module(void) |
| 308 | { |
| 309 | tcf_unregister_action(&act_xt_ops); |
| 310 | tcf_unregister_action(&act_ipt_ops); |
| 311 | } |
| 312 | |
| 313 | module_init(ipt_init_module); |
| 314 | module_exit(ipt_cleanup_module); |