net/netfilter/nft_meta.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nf_tables.h>
  17 #include <linux/in.h>
  18 #include <linux/ip.h>
  19 #include <linux/ipv6.h>
  20 #include <linux/smp.h>
  21 #include <net/dst.h>
  22 #include <net/sock.h>
  23 #include <net/tcp_states.h> /* for TCP_TIME_WAIT */
  24 #include <net/netfilter/nf_tables.h>
  25 #include <net/netfilter/nft_meta.h>
  26
  27 void nft_meta_get_eval(const struct nft_expr *expr,
  28                        struct nft_data data[NFT_REG_MAX + 1],
  29                        const struct nft_pktinfo *pkt)
  30 {
  31         const struct nft_meta *priv = nft_expr_priv(expr);
  32         const struct sk_buff *skb = pkt->skb;
  33         const struct net_device *in = pkt->in, *out = pkt->out;
  34         struct nft_data *dest = &data[priv->dreg];
  35
  36         switch (priv->key) {
  37         case NFT_META_LEN:
  38                 dest->data[0] = skb->len;
  39                 break;
  40         case NFT_META_PROTOCOL:
  41                 *(__be16 *)dest->data = skb->protocol;
  42                 break;
  43         case NFT_META_NFPROTO:
  44                 dest->data[0] = pkt->ops->pf;
  45                 break;
  46         case NFT_META_L4PROTO:
  47                 dest->data[0] = pkt->tprot;
  48                 break;
  49         case NFT_META_PRIORITY:
  50                 dest->data[0] = skb->priority;
  51                 break;
  52         case NFT_META_MARK:
  53                 dest->data[0] = skb->mark;
  54                 break;
  55         case NFT_META_IIF:
  56                 if (in == NULL)
  57                         goto err;
  58                 dest->data[0] = in->ifindex;
  59                 break;
  60         case NFT_META_OIF:
  61                 if (out == NULL)
  62                         goto err;
  63                 dest->data[0] = out->ifindex;
  64                 break;
  65         case NFT_META_IIFNAME:
  66                 if (in == NULL)
  67                         goto err;
  68                 strncpy((char *)dest->data, in->name, sizeof(dest->data));
  69                 break;
  70         case NFT_META_OIFNAME:
  71                 if (out == NULL)
  72                         goto err;
  73                 strncpy((char *)dest->data, out->name, sizeof(dest->data));
  74                 break;
  75         case NFT_META_IIFTYPE:
  76                 if (in == NULL)
  77                         goto err;
  78                 *(u16 *)dest->data = in->type;
  79                 break;
  80         case NFT_META_OIFTYPE:
  81                 if (out == NULL)
  82                         goto err;
  83                 *(u16 *)dest->data = out->type;
  84                 break;
  85         case NFT_META_SKUID:
  86                 if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
  87                         goto err;
  88
  89                 read_lock_bh(&skb->sk->sk_callback_lock);
  90                 if (skb->sk->sk_socket == NULL ||
  91                     skb->sk->sk_socket->file == NULL) {
  92                         read_unlock_bh(&skb->sk->sk_callback_lock);
  93                         goto err;
  94                 }
  95
  96                 dest->data[0] =
  97                         from_kuid_munged(&init_user_ns,
  98                                 skb->sk->sk_socket->file->f_cred->fsuid);
  99                 read_unlock_bh(&skb->sk->sk_callback_lock);
 100                 break;
 101         case NFT_META_SKGID:
 102                 if (skb->sk == NULL || skb->sk->sk_state == TCP_TIME_WAIT)
 103                         goto err;
 104
 105                 read_lock_bh(&skb->sk->sk_callback_lock);
 106                 if (skb->sk->sk_socket == NULL ||
 107                     skb->sk->sk_socket->file == NULL) {
 108                         read_unlock_bh(&skb->sk->sk_callback_lock);
 109                         goto err;
 110                 }
 111                 dest->data[0] =
 112                         from_kgid_munged(&init_user_ns,
 113                                  skb->sk->sk_socket->file->f_cred->fsgid);
 114                 read_unlock_bh(&skb->sk->sk_callback_lock);
 115                 break;
 116 #ifdef CONFIG_IP_ROUTE_CLASSID
 117         case NFT_META_RTCLASSID: {
 118                 const struct dst_entry *dst = skb_dst(skb);
 119
 120                 if (dst == NULL)
 121                         goto err;
 122                 dest->data[0] = dst->tclassid;
 123                 break;
 124         }
 125 #endif
 126 #ifdef CONFIG_NETWORK_SECMARK
 127         case NFT_META_SECMARK:
 128                 dest->data[0] = skb->secmark;
 129                 break;
 130 #endif
 131         case NFT_META_PKTTYPE:
 132                 if (skb->pkt_type != PACKET_LOOPBACK) {
 133                         dest->data[0] = skb->pkt_type;
 134                         break;
 135                 }
 136
 137                 switch (pkt->ops->pf) {
 138                 case NFPROTO_IPV4:
 139                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 140                                 dest->data[0] = PACKET_MULTICAST;
 141                         else
 142                                 dest->data[0] = PACKET_BROADCAST;
 143                         break;
 144                 case NFPROTO_IPV6:
 145                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 146                                 dest->data[0] = PACKET_MULTICAST;
 147                         else
 148                                 dest->data[0] = PACKET_BROADCAST;
 149                         break;
 150                 default:
 151                         WARN_ON(1);
 152                         goto err;
 153                 }
 154                 break;
 155         case NFT_META_CPU:
 156                 dest->data[0] = smp_processor_id();
 157                 break;
 158         default:
 159                 WARN_ON(1);
 160                 goto err;
 161         }
 162         return;
 163
 164 err:
 165         data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 166 }
 167 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 168
 169 void nft_meta_set_eval(const struct nft_expr *expr,
 170                        struct nft_data data[NFT_REG_MAX + 1],
 171                        const struct nft_pktinfo *pkt)
 172 {
 173         const struct nft_meta *meta = nft_expr_priv(expr);
 174         struct sk_buff *skb = pkt->skb;
 175         u32 value = data[meta->sreg].data[0];
 176
 177         switch (meta->key) {
 178         case NFT_META_MARK:
 179                 skb->mark = value;
 180                 break;
 181         case NFT_META_PRIORITY:
 182                 skb->priority = value;
 183                 break;
 184         case NFT_META_NFTRACE:
 185                 skb->nf_trace = 1;
 186                 break;
 187         default:
 188                 WARN_ON(1);
 189         }
 190 }
 191 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 192
 193 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 194         [NFTA_META_DREG]        = { .type = NLA_U32 },
 195         [NFTA_META_KEY]         = { .type = NLA_U32 },
 196         [NFTA_META_SREG]        = { .type = NLA_U32 },
 197 };
 198 EXPORT_SYMBOL_GPL(nft_meta_policy);
 199
 200 int nft_meta_get_init(const struct nft_ctx *ctx,
 201                       const struct nft_expr *expr,
 202                       const struct nlattr * const tb[])
 203 {
 204         struct nft_meta *priv = nft_expr_priv(expr);
 205         int err;
 206
 207         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 208         switch (priv->key) {
 209         case NFT_META_LEN:
 210         case NFT_META_PROTOCOL:
 211         case NFT_META_NFPROTO:
 212         case NFT_META_L4PROTO:
 213         case NFT_META_PRIORITY:
 214         case NFT_META_MARK:
 215         case NFT_META_IIF:
 216         case NFT_META_OIF:
 217         case NFT_META_IIFNAME:
 218         case NFT_META_OIFNAME:
 219         case NFT_META_IIFTYPE:
 220         case NFT_META_OIFTYPE:
 221         case NFT_META_SKUID:
 222         case NFT_META_SKGID:
 223 #ifdef CONFIG_IP_ROUTE_CLASSID
 224         case NFT_META_RTCLASSID:
 225 #endif
 226 #ifdef CONFIG_NETWORK_SECMARK
 227         case NFT_META_SECMARK:
 228 #endif
 229         case NFT_META_PKTTYPE:
 230         case NFT_META_CPU:
 231                 break;
 232         default:
 233                 return -EOPNOTSUPP;
 234         }
 235
 236         priv->dreg = ntohl(nla_get_be32(tb[NFTA_META_DREG]));
 237         err = nft_validate_output_register(priv->dreg);
 238         if (err < 0)
 239                 return err;
 240
 241         err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE);
 242         if (err < 0)
 243                 return err;
 244
 245         return 0;
 246 }
 247 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 248
 249 int nft_meta_set_init(const struct nft_ctx *ctx,
 250                       const struct nft_expr *expr,
 251                       const struct nlattr * const tb[])
 252 {
 253         struct nft_meta *priv = nft_expr_priv(expr);
 254         int err;
 255
 256         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 257         switch (priv->key) {
 258         case NFT_META_MARK:
 259         case NFT_META_PRIORITY:
 260         case NFT_META_NFTRACE:
 261                 break;
 262         default:
 263                 return -EOPNOTSUPP;
 264         }
 265
 266         priv->sreg = ntohl(nla_get_be32(tb[NFTA_META_SREG]));
 267         err = nft_validate_input_register(priv->sreg);
 268         if (err < 0)
 269                 return err;
 270
 271         return 0;
 272 }
 273 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 274
 275 int nft_meta_get_dump(struct sk_buff *skb,
 276                       const struct nft_expr *expr)
 277 {
 278         const struct nft_meta *priv = nft_expr_priv(expr);
 279
 280         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 281                 goto nla_put_failure;
 282         if (nla_put_be32(skb, NFTA_META_DREG, htonl(priv->dreg)))
 283                 goto nla_put_failure;
 284         return 0;
 285
 286 nla_put_failure:
 287         return -1;
 288 }
 289 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 290
 291 int nft_meta_set_dump(struct sk_buff *skb,
 292                       const struct nft_expr *expr)
 293 {
 294         const struct nft_meta *priv = nft_expr_priv(expr);
 295
 296         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 297                 goto nla_put_failure;
 298         if (nla_put_be32(skb, NFTA_META_SREG, htonl(priv->sreg)))
 299                 goto nla_put_failure;
 300
 301         return 0;
 302
 303 nla_put_failure:
 304         return -1;
 305 }
 306 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 307
 308 static struct nft_expr_type nft_meta_type;
 309 static const struct nft_expr_ops nft_meta_get_ops = {
 310         .type           = &nft_meta_type,
 311         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 312         .eval           = nft_meta_get_eval,
 313         .init           = nft_meta_get_init,
 314         .dump           = nft_meta_get_dump,
 315 };
 316
 317 static const struct nft_expr_ops nft_meta_set_ops = {
 318         .type           = &nft_meta_type,
 319         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 320         .eval           = nft_meta_set_eval,
 321         .init           = nft_meta_set_init,
 322         .dump           = nft_meta_set_dump,
 323 };
 324
 325 static const struct nft_expr_ops *
 326 nft_meta_select_ops(const struct nft_ctx *ctx,
 327                     const struct nlattr * const tb[])
 328 {
 329         if (tb[NFTA_META_KEY] == NULL)
 330                 return ERR_PTR(-EINVAL);
 331
 332         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 333                 return ERR_PTR(-EINVAL);
 334
 335         if (tb[NFTA_META_DREG])
 336                 return &nft_meta_get_ops;
 337
 338         if (tb[NFTA_META_SREG])
 339                 return &nft_meta_set_ops;
 340
 341         return ERR_PTR(-EINVAL);
 342 }
 343
 344 static struct nft_expr_type nft_meta_type __read_mostly = {
 345         .name           = "meta",
 346         .select_ops     = &nft_meta_select_ops,
 347         .policy         = nft_meta_policy,
 348         .maxattr        = NFTA_META_MAX,
 349         .owner          = THIS_MODULE,
 350 };
 351
 352 static int __init nft_meta_module_init(void)
 353 {
 354         return nft_register_expr(&nft_meta_type);
 355 }
 356
 357 static void __exit nft_meta_module_exit(void)
 358 {
 359         nft_unregister_expr(&nft_meta_type);
 360 }
 361
 362 module_init(nft_meta_module_init);
 363 module_exit(nft_meta_module_exit);
 364
 365 MODULE_LICENSE("GPL");
 366 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 367 MODULE_ALIAS_NFT_EXPR("meta");