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_regs *regs,
  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 sock *sk;
  35         u32 *dest = &regs->data[priv->dreg];
  36
  37         switch (priv->key) {
  38         case NFT_META_LEN:
  39                 *dest = skb->len;
  40                 break;
  41         case NFT_META_PROTOCOL:
  42                 *dest = 0;
  43                 *(__be16 *)dest = skb->protocol;
  44                 break;
  45         case NFT_META_NFPROTO:
  46                 *dest = pkt->pf;
  47                 break;
  48         case NFT_META_L4PROTO:
  49                 *dest = pkt->tprot;
  50                 break;
  51         case NFT_META_PRIORITY:
  52                 *dest = skb->priority;
  53                 break;
  54         case NFT_META_MARK:
  55                 *dest = skb->mark;
  56                 break;
  57         case NFT_META_IIF:
  58                 if (in == NULL)
  59                         goto err;
  60                 *dest = in->ifindex;
  61                 break;
  62         case NFT_META_OIF:
  63                 if (out == NULL)
  64                         goto err;
  65                 *dest = out->ifindex;
  66                 break;
  67         case NFT_META_IIFNAME:
  68                 if (in == NULL)
  69                         goto err;
  70                 strncpy((char *)dest, in->name, IFNAMSIZ);
  71                 break;
  72         case NFT_META_OIFNAME:
  73                 if (out == NULL)
  74                         goto err;
  75                 strncpy((char *)dest, out->name, IFNAMSIZ);
  76                 break;
  77         case NFT_META_IIFTYPE:
  78                 if (in == NULL)
  79                         goto err;
  80                 *dest = 0;
  81                 *(u16 *)dest = in->type;
  82                 break;
  83         case NFT_META_OIFTYPE:
  84                 if (out == NULL)
  85                         goto err;
  86                 *dest = 0;
  87                 *(u16 *)dest = out->type;
  88                 break;
  89         case NFT_META_SKUID:
  90                 sk = skb_to_full_sk(skb);
  91                 if (!sk || !sk_fullsock(sk))
  92                         goto err;
  93
  94                 read_lock_bh(&sk->sk_callback_lock);
  95                 if (sk->sk_socket == NULL ||
  96                     sk->sk_socket->file == NULL) {
  97                         read_unlock_bh(&sk->sk_callback_lock);
  98                         goto err;
  99                 }
 100
 101                 *dest = from_kuid_munged(&init_user_ns,
 102                                 sk->sk_socket->file->f_cred->fsuid);
 103                 read_unlock_bh(&sk->sk_callback_lock);
 104                 break;
 105         case NFT_META_SKGID:
 106                 sk = skb_to_full_sk(skb);
 107                 if (!sk || !sk_fullsock(sk))
 108                         goto err;
 109
 110                 read_lock_bh(&sk->sk_callback_lock);
 111                 if (sk->sk_socket == NULL ||
 112                     sk->sk_socket->file == NULL) {
 113                         read_unlock_bh(&sk->sk_callback_lock);
 114                         goto err;
 115                 }
 116                 *dest = from_kgid_munged(&init_user_ns,
 117                                  sk->sk_socket->file->f_cred->fsgid);
 118                 read_unlock_bh(&sk->sk_callback_lock);
 119                 break;
 120 #ifdef CONFIG_IP_ROUTE_CLASSID
 121         case NFT_META_RTCLASSID: {
 122                 const struct dst_entry *dst = skb_dst(skb);
 123
 124                 if (dst == NULL)
 125                         goto err;
 126                 *dest = dst->tclassid;
 127                 break;
 128         }
 129 #endif
 130 #ifdef CONFIG_NETWORK_SECMARK
 131         case NFT_META_SECMARK:
 132                 *dest = skb->secmark;
 133                 break;
 134 #endif
 135         case NFT_META_PKTTYPE:
 136                 if (skb->pkt_type != PACKET_LOOPBACK) {
 137                         *dest = skb->pkt_type;
 138                         break;
 139                 }
 140
 141                 switch (pkt->pf) {
 142                 case NFPROTO_IPV4:
 143                         if (ipv4_is_multicast(ip_hdr(skb)->daddr))
 144                                 *dest = PACKET_MULTICAST;
 145                         else
 146                                 *dest = PACKET_BROADCAST;
 147                         break;
 148                 case NFPROTO_IPV6:
 149                         if (ipv6_hdr(skb)->daddr.s6_addr[0] == 0xFF)
 150                                 *dest = PACKET_MULTICAST;
 151                         else
 152                                 *dest = PACKET_BROADCAST;
 153                         break;
 154                 case NFPROTO_NETDEV:
 155                         switch (skb->protocol) {
 156                         case htons(ETH_P_IP): {
 157                                 int noff = skb_network_offset(skb);
 158                                 struct iphdr *iph, _iph;
 159
 160                                 iph = skb_header_pointer(skb, noff,
 161                                                          sizeof(_iph), &_iph);
 162                                 if (!iph)
 163                                         goto err;
 164
 165                                 if (ipv4_is_multicast(iph->daddr))
 166                                         *dest = PACKET_MULTICAST;
 167                                 else
 168                                         *dest = PACKET_BROADCAST;
 169
 170                                 break;
 171                         }
 172                         case htons(ETH_P_IPV6):
 173                                 *dest = PACKET_MULTICAST;
 174                                 break;
 175                         default:
 176                                 WARN_ON_ONCE(1);
 177                                 goto err;
 178                         }
 179                         break;
 180                 default:
 181                         WARN_ON_ONCE(1);
 182                         goto err;
 183                 }
 184                 break;
 185         case NFT_META_CPU:
 186                 *dest = raw_smp_processor_id();
 187                 break;
 188         case NFT_META_IIFGROUP:
 189                 if (in == NULL)
 190                         goto err;
 191                 *dest = in->group;
 192                 break;
 193         case NFT_META_OIFGROUP:
 194                 if (out == NULL)
 195                         goto err;
 196                 *dest = out->group;
 197                 break;
 198 #ifdef CONFIG_CGROUP_NET_CLASSID
 199         case NFT_META_CGROUP:
 200                 sk = skb_to_full_sk(skb);
 201                 if (!sk || !sk_fullsock(sk))
 202                         goto err;
 203                 *dest = sk->sk_classid;
 204                 break;
 205 #endif
 206         default:
 207                 WARN_ON(1);
 208                 goto err;
 209         }
 210         return;
 211
 212 err:
 213         regs->verdict.code = NFT_BREAK;
 214 }
 215 EXPORT_SYMBOL_GPL(nft_meta_get_eval);
 216
 217 void nft_meta_set_eval(const struct nft_expr *expr,
 218                        struct nft_regs *regs,
 219                        const struct nft_pktinfo *pkt)
 220 {
 221         const struct nft_meta *meta = nft_expr_priv(expr);
 222         struct sk_buff *skb = pkt->skb;
 223         u32 value = regs->data[meta->sreg];
 224
 225         switch (meta->key) {
 226         case NFT_META_MARK:
 227                 skb->mark = value;
 228                 break;
 229         case NFT_META_PRIORITY:
 230                 skb->priority = value;
 231                 break;
 232         case NFT_META_NFTRACE:
 233                 skb->nf_trace = 1;
 234                 break;
 235         default:
 236                 WARN_ON(1);
 237         }
 238 }
 239 EXPORT_SYMBOL_GPL(nft_meta_set_eval);
 240
 241 const struct nla_policy nft_meta_policy[NFTA_META_MAX + 1] = {
 242         [NFTA_META_DREG]        = { .type = NLA_U32 },
 243         [NFTA_META_KEY]         = { .type = NLA_U32 },
 244         [NFTA_META_SREG]        = { .type = NLA_U32 },
 245 };
 246 EXPORT_SYMBOL_GPL(nft_meta_policy);
 247
 248 int nft_meta_get_init(const struct nft_ctx *ctx,
 249                       const struct nft_expr *expr,
 250                       const struct nlattr * const tb[])
 251 {
 252         struct nft_meta *priv = nft_expr_priv(expr);
 253         unsigned int len;
 254
 255         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 256         switch (priv->key) {
 257         case NFT_META_PROTOCOL:
 258         case NFT_META_IIFTYPE:
 259         case NFT_META_OIFTYPE:
 260                 len = sizeof(u16);
 261                 break;
 262         case NFT_META_NFPROTO:
 263         case NFT_META_L4PROTO:
 264         case NFT_META_LEN:
 265         case NFT_META_PRIORITY:
 266         case NFT_META_MARK:
 267         case NFT_META_IIF:
 268         case NFT_META_OIF:
 269         case NFT_META_SKUID:
 270         case NFT_META_SKGID:
 271 #ifdef CONFIG_IP_ROUTE_CLASSID
 272         case NFT_META_RTCLASSID:
 273 #endif
 274 #ifdef CONFIG_NETWORK_SECMARK
 275         case NFT_META_SECMARK:
 276 #endif
 277         case NFT_META_PKTTYPE:
 278         case NFT_META_CPU:
 279         case NFT_META_IIFGROUP:
 280         case NFT_META_OIFGROUP:
 281 #ifdef CONFIG_CGROUP_NET_CLASSID
 282         case NFT_META_CGROUP:
 283 #endif
 284                 len = sizeof(u32);
 285                 break;
 286         case NFT_META_IIFNAME:
 287         case NFT_META_OIFNAME:
 288                 len = IFNAMSIZ;
 289                 break;
 290         default:
 291                 return -EOPNOTSUPP;
 292         }
 293
 294         priv->dreg = nft_parse_register(tb[NFTA_META_DREG]);
 295         return nft_validate_register_store(ctx, priv->dreg, NULL,
 296                                            NFT_DATA_VALUE, len);
 297 }
 298 EXPORT_SYMBOL_GPL(nft_meta_get_init);
 299
 300 int nft_meta_set_init(const struct nft_ctx *ctx,
 301                       const struct nft_expr *expr,
 302                       const struct nlattr * const tb[])
 303 {
 304         struct nft_meta *priv = nft_expr_priv(expr);
 305         unsigned int len;
 306         int err;
 307
 308         priv->key = ntohl(nla_get_be32(tb[NFTA_META_KEY]));
 309         switch (priv->key) {
 310         case NFT_META_MARK:
 311         case NFT_META_PRIORITY:
 312                 len = sizeof(u32);
 313                 break;
 314         case NFT_META_NFTRACE:
 315                 len = sizeof(u8);
 316                 break;
 317         default:
 318                 return -EOPNOTSUPP;
 319         }
 320
 321         priv->sreg = nft_parse_register(tb[NFTA_META_SREG]);
 322         err = nft_validate_register_load(priv->sreg, len);
 323         if (err < 0)
 324                 return err;
 325
 326         return 0;
 327 }
 328 EXPORT_SYMBOL_GPL(nft_meta_set_init);
 329
 330 int nft_meta_get_dump(struct sk_buff *skb,
 331                       const struct nft_expr *expr)
 332 {
 333         const struct nft_meta *priv = nft_expr_priv(expr);
 334
 335         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 336                 goto nla_put_failure;
 337         if (nft_dump_register(skb, NFTA_META_DREG, priv->dreg))
 338                 goto nla_put_failure;
 339         return 0;
 340
 341 nla_put_failure:
 342         return -1;
 343 }
 344 EXPORT_SYMBOL_GPL(nft_meta_get_dump);
 345
 346 int nft_meta_set_dump(struct sk_buff *skb,
 347                       const struct nft_expr *expr)
 348 {
 349         const struct nft_meta *priv = nft_expr_priv(expr);
 350
 351         if (nla_put_be32(skb, NFTA_META_KEY, htonl(priv->key)))
 352                 goto nla_put_failure;
 353         if (nft_dump_register(skb, NFTA_META_SREG, priv->sreg))
 354                 goto nla_put_failure;
 355
 356         return 0;
 357
 358 nla_put_failure:
 359         return -1;
 360 }
 361 EXPORT_SYMBOL_GPL(nft_meta_set_dump);
 362
 363 static struct nft_expr_type nft_meta_type;
 364 static const struct nft_expr_ops nft_meta_get_ops = {
 365         .type           = &nft_meta_type,
 366         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 367         .eval           = nft_meta_get_eval,
 368         .init           = nft_meta_get_init,
 369         .dump           = nft_meta_get_dump,
 370 };
 371
 372 static const struct nft_expr_ops nft_meta_set_ops = {
 373         .type           = &nft_meta_type,
 374         .size           = NFT_EXPR_SIZE(sizeof(struct nft_meta)),
 375         .eval           = nft_meta_set_eval,
 376         .init           = nft_meta_set_init,
 377         .dump           = nft_meta_set_dump,
 378 };
 379
 380 static const struct nft_expr_ops *
 381 nft_meta_select_ops(const struct nft_ctx *ctx,
 382                     const struct nlattr * const tb[])
 383 {
 384         if (tb[NFTA_META_KEY] == NULL)
 385                 return ERR_PTR(-EINVAL);
 386
 387         if (tb[NFTA_META_DREG] && tb[NFTA_META_SREG])
 388                 return ERR_PTR(-EINVAL);
 389
 390         if (tb[NFTA_META_DREG])
 391                 return &nft_meta_get_ops;
 392
 393         if (tb[NFTA_META_SREG])
 394                 return &nft_meta_set_ops;
 395
 396         return ERR_PTR(-EINVAL);
 397 }
 398
 399 static struct nft_expr_type nft_meta_type __read_mostly = {
 400         .name           = "meta",
 401         .select_ops     = &nft_meta_select_ops,
 402         .policy         = nft_meta_policy,
 403         .maxattr        = NFTA_META_MAX,
 404         .owner          = THIS_MODULE,
 405 };
 406
 407 static int __init nft_meta_module_init(void)
 408 {
 409         return nft_register_expr(&nft_meta_type);
 410 }
 411
 412 static void __exit nft_meta_module_exit(void)
 413 {
 414         nft_unregister_expr(&nft_meta_type);
 415 }
 416
 417 module_init(nft_meta_module_init);
 418 module_exit(nft_meta_module_exit);
 419
 420 MODULE_LICENSE("GPL");
 421 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 422 MODULE_ALIAS_NFT_EXPR("meta");