net/netfilter/nft_byteorder.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 <asm/unaligned.h>
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/netlink.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_tables_core.h>
  19 #include <net/netfilter/nf_tables.h>
  20
  21 struct nft_byteorder {
  22         enum nft_registers      sreg:8;
  23         enum nft_registers      dreg:8;
  24         enum nft_byteorder_ops  op:8;
  25         u8                      len;
  26         u8                      size;
  27 };
  28
  29 static void nft_byteorder_eval(const struct nft_expr *expr,
  30                                struct nft_regs *regs,
  31                                const struct nft_pktinfo *pkt)
  32 {
  33         const struct nft_byteorder *priv = nft_expr_priv(expr);
  34         u32 *src = &regs->data[priv->sreg];
  35         u32 *dst = &regs->data[priv->dreg];
  36         union { u32 u32; u16 u16; } *s, *d;
  37         unsigned int i;
  38
  39         s = (void *)src;
  40         d = (void *)dst;
  41
  42         switch (priv->size) {
  43         case 8: {
  44                 u64 src64;
  45
  46                 switch (priv->op) {
  47                 case NFT_BYTEORDER_NTOH:
  48                         for (i = 0; i < priv->len / 8; i++) {
  49                                 src64 = get_unaligned((u64 *)&src[i]);
  50                                 put_unaligned_be64(src64, &dst[i]);
  51                         }
  52                         break;
  53                 case NFT_BYTEORDER_HTON:
  54                         for (i = 0; i < priv->len / 8; i++) {
  55                                 src64 = get_unaligned_be64(&src[i]);
  56                                 put_unaligned(src64, (u64 *)&dst[i]);
  57                         }
  58                         break;
  59                 }
  60                 break;
  61         }
  62         case 4:
  63                 switch (priv->op) {
  64                 case NFT_BYTEORDER_NTOH:
  65                         for (i = 0; i < priv->len / 4; i++)
  66                                 d[i].u32 = ntohl((__force __be32)s[i].u32);
  67                         break;
  68                 case NFT_BYTEORDER_HTON:
  69                         for (i = 0; i < priv->len / 4; i++)
  70                                 d[i].u32 = (__force __u32)htonl(s[i].u32);
  71                         break;
  72                 }
  73                 break;
  74         case 2:
  75                 switch (priv->op) {
  76                 case NFT_BYTEORDER_NTOH:
  77                         for (i = 0; i < priv->len / 2; i++)
  78                                 d[i].u16 = ntohs((__force __be16)s[i].u16);
  79                         break;
  80                 case NFT_BYTEORDER_HTON:
  81                         for (i = 0; i < priv->len / 2; i++)
  82                                 d[i].u16 = (__force __u16)htons(s[i].u16);
  83                         break;
  84                 }
  85                 break;
  86         }
  87 }
  88
  89 static const struct nla_policy nft_byteorder_policy[NFTA_BYTEORDER_MAX + 1] = {
  90         [NFTA_BYTEORDER_SREG]   = { .type = NLA_U32 },
  91         [NFTA_BYTEORDER_DREG]   = { .type = NLA_U32 },
  92         [NFTA_BYTEORDER_OP]     = { .type = NLA_U32 },
  93         [NFTA_BYTEORDER_LEN]    = { .type = NLA_U32 },
  94         [NFTA_BYTEORDER_SIZE]   = { .type = NLA_U32 },
  95 };
  96
  97 static int nft_byteorder_init(const struct nft_ctx *ctx,
  98                               const struct nft_expr *expr,
  99                               const struct nlattr * const tb[])
 100 {
 101         struct nft_byteorder *priv = nft_expr_priv(expr);
 102         int err;
 103
 104         if (tb[NFTA_BYTEORDER_SREG] == NULL ||
 105             tb[NFTA_BYTEORDER_DREG] == NULL ||
 106             tb[NFTA_BYTEORDER_LEN] == NULL ||
 107             tb[NFTA_BYTEORDER_SIZE] == NULL ||
 108             tb[NFTA_BYTEORDER_OP] == NULL)
 109                 return -EINVAL;
 110
 111         priv->op = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_OP]));
 112         switch (priv->op) {
 113         case NFT_BYTEORDER_NTOH:
 114         case NFT_BYTEORDER_HTON:
 115                 break;
 116         default:
 117                 return -EINVAL;
 118         }
 119
 120         priv->size = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_SIZE]));
 121         switch (priv->size) {
 122         case 2:
 123         case 4:
 124         case 8:
 125                 break;
 126         default:
 127                 return -EINVAL;
 128         }
 129
 130         priv->sreg = nft_parse_register(tb[NFTA_BYTEORDER_SREG]);
 131         priv->len  = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_LEN]));
 132         err = nft_validate_register_load(priv->sreg, priv->len);
 133         if (err < 0)
 134                 return err;
 135
 136         priv->dreg = nft_parse_register(tb[NFTA_BYTEORDER_DREG]);
 137         return nft_validate_register_store(ctx, priv->dreg, NULL,
 138                                            NFT_DATA_VALUE, priv->len);
 139 }
 140
 141 static int nft_byteorder_dump(struct sk_buff *skb, const struct nft_expr *expr)
 142 {
 143         const struct nft_byteorder *priv = nft_expr_priv(expr);
 144
 145         if (nft_dump_register(skb, NFTA_BYTEORDER_SREG, priv->sreg))
 146                 goto nla_put_failure;
 147         if (nft_dump_register(skb, NFTA_BYTEORDER_DREG, priv->dreg))
 148                 goto nla_put_failure;
 149         if (nla_put_be32(skb, NFTA_BYTEORDER_OP, htonl(priv->op)))
 150                 goto nla_put_failure;
 151         if (nla_put_be32(skb, NFTA_BYTEORDER_LEN, htonl(priv->len)))
 152                 goto nla_put_failure;
 153         if (nla_put_be32(skb, NFTA_BYTEORDER_SIZE, htonl(priv->size)))
 154                 goto nla_put_failure;
 155         return 0;
 156
 157 nla_put_failure:
 158         return -1;
 159 }
 160
 161 static struct nft_expr_type nft_byteorder_type;
 162 static const struct nft_expr_ops nft_byteorder_ops = {
 163         .type           = &nft_byteorder_type,
 164         .size           = NFT_EXPR_SIZE(sizeof(struct nft_byteorder)),
 165         .eval           = nft_byteorder_eval,
 166         .init           = nft_byteorder_init,
 167         .dump           = nft_byteorder_dump,
 168 };
 169
 170 static struct nft_expr_type nft_byteorder_type __read_mostly = {
 171         .name           = "byteorder",
 172         .ops            = &nft_byteorder_ops,
 173         .policy         = nft_byteorder_policy,
 174         .maxattr        = NFTA_BYTEORDER_MAX,
 175         .owner          = THIS_MODULE,
 176 };
 177
 178 int __init nft_byteorder_module_init(void)
 179 {
 180         return nft_register_expr(&nft_byteorder_type);
 181 }
 182
 183 void nft_byteorder_module_exit(void)
 184 {
 185         nft_unregister_expr(&nft_byteorder_type);
 186 }