| 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 <net/netfilter/nf_tables_core.h> |
| 18 | #include <net/netfilter/nf_tables.h> |
| 19 | |
| 20 | struct nft_bitwise { |
| 21 | enum nft_registers sreg:8; |
| 22 | enum nft_registers dreg:8; |
| 23 | u8 len; |
| 24 | struct nft_data mask; |
| 25 | struct nft_data xor; |
| 26 | }; |
| 27 | |
| 28 | static void nft_bitwise_eval(const struct nft_expr *expr, |
| 29 | struct nft_data data[NFT_REG_MAX + 1], |
| 30 | const struct nft_pktinfo *pkt) |
| 31 | { |
| 32 | const struct nft_bitwise *priv = nft_expr_priv(expr); |
| 33 | const struct nft_data *src = &data[priv->sreg]; |
| 34 | struct nft_data *dst = &data[priv->dreg]; |
| 35 | unsigned int i; |
| 36 | |
| 37 | for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++) { |
| 38 | dst->data[i] = (src->data[i] & priv->mask.data[i]) ^ |
| 39 | priv->xor.data[i]; |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = { |
| 44 | [NFTA_BITWISE_SREG] = { .type = NLA_U32 }, |
| 45 | [NFTA_BITWISE_DREG] = { .type = NLA_U32 }, |
| 46 | [NFTA_BITWISE_LEN] = { .type = NLA_U32 }, |
| 47 | [NFTA_BITWISE_MASK] = { .type = NLA_NESTED }, |
| 48 | [NFTA_BITWISE_XOR] = { .type = NLA_NESTED }, |
| 49 | }; |
| 50 | |
| 51 | static int nft_bitwise_init(const struct nft_ctx *ctx, |
| 52 | const struct nft_expr *expr, |
| 53 | const struct nlattr * const tb[]) |
| 54 | { |
| 55 | struct nft_bitwise *priv = nft_expr_priv(expr); |
| 56 | struct nft_data_desc d1, d2; |
| 57 | int err; |
| 58 | |
| 59 | if (tb[NFTA_BITWISE_SREG] == NULL || |
| 60 | tb[NFTA_BITWISE_DREG] == NULL || |
| 61 | tb[NFTA_BITWISE_LEN] == NULL || |
| 62 | tb[NFTA_BITWISE_MASK] == NULL || |
| 63 | tb[NFTA_BITWISE_XOR] == NULL) |
| 64 | return -EINVAL; |
| 65 | |
| 66 | priv->sreg = ntohl(nla_get_be32(tb[NFTA_BITWISE_SREG])); |
| 67 | err = nft_validate_input_register(priv->sreg); |
| 68 | if (err < 0) |
| 69 | return err; |
| 70 | |
| 71 | priv->dreg = ntohl(nla_get_be32(tb[NFTA_BITWISE_DREG])); |
| 72 | err = nft_validate_output_register(priv->dreg); |
| 73 | if (err < 0) |
| 74 | return err; |
| 75 | err = nft_validate_data_load(ctx, priv->dreg, NULL, NFT_DATA_VALUE); |
| 76 | if (err < 0) |
| 77 | return err; |
| 78 | |
| 79 | priv->len = ntohl(nla_get_be32(tb[NFTA_BITWISE_LEN])); |
| 80 | |
| 81 | err = nft_data_init(NULL, &priv->mask, &d1, tb[NFTA_BITWISE_MASK]); |
| 82 | if (err < 0) |
| 83 | return err; |
| 84 | if (d1.len != priv->len) |
| 85 | return -EINVAL; |
| 86 | |
| 87 | err = nft_data_init(NULL, &priv->xor, &d2, tb[NFTA_BITWISE_XOR]); |
| 88 | if (err < 0) |
| 89 | return err; |
| 90 | if (d2.len != priv->len) |
| 91 | return -EINVAL; |
| 92 | |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr) |
| 97 | { |
| 98 | const struct nft_bitwise *priv = nft_expr_priv(expr); |
| 99 | |
| 100 | if (nla_put_be32(skb, NFTA_BITWISE_SREG, htonl(priv->sreg))) |
| 101 | goto nla_put_failure; |
| 102 | if (nla_put_be32(skb, NFTA_BITWISE_DREG, htonl(priv->dreg))) |
| 103 | goto nla_put_failure; |
| 104 | if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len))) |
| 105 | goto nla_put_failure; |
| 106 | |
| 107 | if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask, |
| 108 | NFT_DATA_VALUE, priv->len) < 0) |
| 109 | goto nla_put_failure; |
| 110 | |
| 111 | if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor, |
| 112 | NFT_DATA_VALUE, priv->len) < 0) |
| 113 | goto nla_put_failure; |
| 114 | |
| 115 | return 0; |
| 116 | |
| 117 | nla_put_failure: |
| 118 | return -1; |
| 119 | } |
| 120 | |
| 121 | static struct nft_expr_type nft_bitwise_type; |
| 122 | static const struct nft_expr_ops nft_bitwise_ops = { |
| 123 | .type = &nft_bitwise_type, |
| 124 | .size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)), |
| 125 | .eval = nft_bitwise_eval, |
| 126 | .init = nft_bitwise_init, |
| 127 | .dump = nft_bitwise_dump, |
| 128 | }; |
| 129 | |
| 130 | static struct nft_expr_type nft_bitwise_type __read_mostly = { |
| 131 | .name = "bitwise", |
| 132 | .ops = &nft_bitwise_ops, |
| 133 | .policy = nft_bitwise_policy, |
| 134 | .maxattr = NFTA_BITWISE_MAX, |
| 135 | .owner = THIS_MODULE, |
| 136 | }; |
| 137 | |
| 138 | int __init nft_bitwise_module_init(void) |
| 139 | { |
| 140 | return nft_register_expr(&nft_bitwise_type); |
| 141 | } |
| 142 | |
| 143 | void nft_bitwise_module_exit(void) |
| 144 | { |
| 145 | nft_unregister_expr(&nft_bitwise_type); |
| 146 | } |