net/netfilter/nft_byteorder.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   4  *
   5  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   6  */
   7
   8 #include <asm/unaligned.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/netlink.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter/nf_tables.h>
  15 #include <net/netfilter/nf_tables_core.h>
  16 #include <net/netfilter/nf_tables.h>
  17
  18 struct nft_byteorder {
  19         u8                      sreg;
  20         u8                      dreg;
  21         enum nft_byteorder_ops  op:8;
  22         u8                      len;
  23         u8                      size;
  24 };
  25
  26 void nft_byteorder_eval(const struct nft_expr *expr,
  27                         struct nft_regs *regs,
  28                         const struct nft_pktinfo *pkt)
  29 {
  30         const struct nft_byteorder *priv = nft_expr_priv(expr);
  31         u32 *src = &regs->data[priv->sreg];
  32         u32 *dst = &regs->data[priv->dreg];
  33         union { u32 u32; u16 u16; } *s, *d;
  34         unsigned int i;
  35
  36         s = (void *)src;
  37         d = (void *)dst;
  38
  39         switch (priv->size) {
  40         case 8: {
  41                 u64 src64;
  42
  43                 switch (priv->op) {
  44                 case NFT_BYTEORDER_NTOH:
  45                         for (i = 0; i < priv->len / 8; i++) {
  46                                 src64 = nft_reg_load64(&src[i]);
  47                                 nft_reg_store64(&dst[i], be64_to_cpu(src64));
  48                         }
  49                         break;
  50                 case NFT_BYTEORDER_HTON:
  51                         for (i = 0; i < priv->len / 8; i++) {
  52                                 src64 = (__force __u64)
  53                                         cpu_to_be64(nft_reg_load64(&src[i]));
  54                                 nft_reg_store64(&dst[i], src64);
  55                         }
  56                         break;
  57                 }
  58                 break;
  59         }
  60         case 4:
  61                 switch (priv->op) {
  62                 case NFT_BYTEORDER_NTOH:
  63                         for (i = 0; i < priv->len / 4; i++)
  64                                 d[i].u32 = ntohl((__force __be32)s[i].u32);
  65                         break;
  66                 case NFT_BYTEORDER_HTON:
  67                         for (i = 0; i < priv->len / 4; i++)
  68                                 d[i].u32 = (__force __u32)htonl(s[i].u32);
  69                         break;
  70                 }
  71                 break;
  72         case 2:
  73                 switch (priv->op) {
  74                 case NFT_BYTEORDER_NTOH:
  75                         for (i = 0; i < priv->len / 2; i++)
  76                                 d[i].u16 = ntohs((__force __be16)s[i].u16);
  77                         break;
  78                 case NFT_BYTEORDER_HTON:
  79                         for (i = 0; i < priv->len / 2; i++)
  80                                 d[i].u16 = (__force __u16)htons(s[i].u16);
  81                         break;
  82                 }
  83                 break;
  84         }
  85 }
  86
  87 static const struct nla_policy nft_byteorder_policy[NFTA_BYTEORDER_MAX + 1] = {
  88         [NFTA_BYTEORDER_SREG]   = { .type = NLA_U32 },
  89         [NFTA_BYTEORDER_DREG]   = { .type = NLA_U32 },
  90         [NFTA_BYTEORDER_OP]     = { .type = NLA_U32 },
  91         [NFTA_BYTEORDER_LEN]    = { .type = NLA_U32 },
  92         [NFTA_BYTEORDER_SIZE]   = { .type = NLA_U32 },
  93 };
  94
  95 static int nft_byteorder_init(const struct nft_ctx *ctx,
  96                               const struct nft_expr *expr,
  97                               const struct nlattr * const tb[])
  98 {
  99         struct nft_byteorder *priv = nft_expr_priv(expr);
 100         u32 size, len;
 101         int err;
 102
 103         if (tb[NFTA_BYTEORDER_SREG] == NULL ||
 104             tb[NFTA_BYTEORDER_DREG] == NULL ||
 105             tb[NFTA_BYTEORDER_LEN] == NULL ||
 106             tb[NFTA_BYTEORDER_SIZE] == NULL ||
 107             tb[NFTA_BYTEORDER_OP] == NULL)
 108                 return -EINVAL;
 109
 110         priv->op = ntohl(nla_get_be32(tb[NFTA_BYTEORDER_OP]));
 111         switch (priv->op) {
 112         case NFT_BYTEORDER_NTOH:
 113         case NFT_BYTEORDER_HTON:
 114                 break;
 115         default:
 116                 return -EINVAL;
 117         }
 118
 119         err = nft_parse_u32_check(tb[NFTA_BYTEORDER_SIZE], U8_MAX, &size);
 120         if (err < 0)
 121                 return err;
 122
 123         priv->size = size;
 124
 125         switch (priv->size) {
 126         case 2:
 127         case 4:
 128         case 8:
 129                 break;
 130         default:
 131                 return -EINVAL;
 132         }
 133
 134         err = nft_parse_u32_check(tb[NFTA_BYTEORDER_LEN], U8_MAX, &len);
 135         if (err < 0)
 136                 return err;
 137
 138         priv->len = len;
 139
 140         err = nft_parse_register_load(tb[NFTA_BYTEORDER_SREG], &priv->sreg,
 141                                       priv->len);
 142         if (err < 0)
 143                 return err;
 144
 145         return nft_parse_register_store(ctx, tb[NFTA_BYTEORDER_DREG],
 146                                         &priv->dreg, NULL, NFT_DATA_VALUE,
 147                                         priv->len);
 148 }
 149
 150 static int nft_byteorder_dump(struct sk_buff *skb, const struct nft_expr *expr)
 151 {
 152         const struct nft_byteorder *priv = nft_expr_priv(expr);
 153
 154         if (nft_dump_register(skb, NFTA_BYTEORDER_SREG, priv->sreg))
 155                 goto nla_put_failure;
 156         if (nft_dump_register(skb, NFTA_BYTEORDER_DREG, priv->dreg))
 157                 goto nla_put_failure;
 158         if (nla_put_be32(skb, NFTA_BYTEORDER_OP, htonl(priv->op)))
 159                 goto nla_put_failure;
 160         if (nla_put_be32(skb, NFTA_BYTEORDER_LEN, htonl(priv->len)))
 161                 goto nla_put_failure;
 162         if (nla_put_be32(skb, NFTA_BYTEORDER_SIZE, htonl(priv->size)))
 163                 goto nla_put_failure;
 164         return 0;
 165
 166 nla_put_failure:
 167         return -1;
 168 }
 169
 170 static const struct nft_expr_ops nft_byteorder_ops = {
 171         .type           = &nft_byteorder_type,
 172         .size           = NFT_EXPR_SIZE(sizeof(struct nft_byteorder)),
 173         .eval           = nft_byteorder_eval,
 174         .init           = nft_byteorder_init,
 175         .dump           = nft_byteorder_dump,
 176 };
 177
 178 struct nft_expr_type nft_byteorder_type __read_mostly = {
 179         .name           = "byteorder",
 180         .ops            = &nft_byteorder_ops,
 181         .policy         = nft_byteorder_policy,
 182         .maxattr        = NFTA_BYTEORDER_MAX,
 183         .owner          = THIS_MODULE,
 184 };