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![Jeremy Sowden](/assets/img/avatar_default.png)
Hitherto nft_bitwise has only supported boolean operations: NOT, AND, OR and XOR. Extend it to do shifts as well. Signed-off-by: Jeremy Sowden <jeremy@azazel.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
301 lines
7.1 KiB
C
301 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables_offload.h>
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struct nft_bitwise {
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enum nft_registers sreg:8;
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enum nft_registers dreg:8;
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enum nft_bitwise_ops op:8;
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u8 len;
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struct nft_data mask;
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struct nft_data xor;
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struct nft_data data;
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};
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static void nft_bitwise_eval_bool(u32 *dst, const u32 *src,
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const struct nft_bitwise *priv)
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{
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unsigned int i;
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for (i = 0; i < DIV_ROUND_UP(priv->len, 4); i++)
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dst[i] = (src[i] & priv->mask.data[i]) ^ priv->xor.data[i];
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}
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static void nft_bitwise_eval_lshift(u32 *dst, const u32 *src,
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const struct nft_bitwise *priv)
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{
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u32 shift = priv->data.data[0];
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unsigned int i;
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u32 carry = 0;
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for (i = DIV_ROUND_UP(priv->len, sizeof(u32)); i > 0; i--) {
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dst[i - 1] = (src[i - 1] << shift) | carry;
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carry = src[i - 1] >> (BITS_PER_TYPE(u32) - shift);
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}
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}
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static void nft_bitwise_eval_rshift(u32 *dst, const u32 *src,
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const struct nft_bitwise *priv)
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{
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u32 shift = priv->data.data[0];
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unsigned int i;
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u32 carry = 0;
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for (i = 0; i < DIV_ROUND_UP(priv->len, sizeof(u32)); i++) {
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dst[i] = carry | (src[i] >> shift);
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carry = src[i] << (BITS_PER_TYPE(u32) - shift);
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}
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}
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void nft_bitwise_eval(const struct nft_expr *expr,
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struct nft_regs *regs, const struct nft_pktinfo *pkt)
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{
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const struct nft_bitwise *priv = nft_expr_priv(expr);
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const u32 *src = ®s->data[priv->sreg];
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u32 *dst = ®s->data[priv->dreg];
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switch (priv->op) {
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case NFT_BITWISE_BOOL:
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nft_bitwise_eval_bool(dst, src, priv);
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break;
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case NFT_BITWISE_LSHIFT:
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nft_bitwise_eval_lshift(dst, src, priv);
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break;
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case NFT_BITWISE_RSHIFT:
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nft_bitwise_eval_rshift(dst, src, priv);
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break;
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}
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}
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static const struct nla_policy nft_bitwise_policy[NFTA_BITWISE_MAX + 1] = {
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[NFTA_BITWISE_SREG] = { .type = NLA_U32 },
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[NFTA_BITWISE_DREG] = { .type = NLA_U32 },
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[NFTA_BITWISE_LEN] = { .type = NLA_U32 },
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[NFTA_BITWISE_MASK] = { .type = NLA_NESTED },
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[NFTA_BITWISE_XOR] = { .type = NLA_NESTED },
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[NFTA_BITWISE_OP] = { .type = NLA_U32 },
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[NFTA_BITWISE_DATA] = { .type = NLA_NESTED },
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};
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static int nft_bitwise_init_bool(struct nft_bitwise *priv,
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const struct nlattr *const tb[])
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{
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struct nft_data_desc d1, d2;
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int err;
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if (tb[NFTA_BITWISE_DATA])
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return -EINVAL;
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if (!tb[NFTA_BITWISE_MASK] ||
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!tb[NFTA_BITWISE_XOR])
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return -EINVAL;
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err = nft_data_init(NULL, &priv->mask, sizeof(priv->mask), &d1,
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tb[NFTA_BITWISE_MASK]);
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if (err < 0)
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return err;
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if (d1.type != NFT_DATA_VALUE || d1.len != priv->len) {
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err = -EINVAL;
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goto err1;
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}
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err = nft_data_init(NULL, &priv->xor, sizeof(priv->xor), &d2,
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tb[NFTA_BITWISE_XOR]);
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if (err < 0)
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goto err1;
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if (d2.type != NFT_DATA_VALUE || d2.len != priv->len) {
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err = -EINVAL;
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goto err2;
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}
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return 0;
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err2:
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nft_data_release(&priv->xor, d2.type);
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err1:
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nft_data_release(&priv->mask, d1.type);
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return err;
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}
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static int nft_bitwise_init_shift(struct nft_bitwise *priv,
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const struct nlattr *const tb[])
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{
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struct nft_data_desc d;
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int err;
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if (tb[NFTA_BITWISE_MASK] ||
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tb[NFTA_BITWISE_XOR])
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return -EINVAL;
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if (!tb[NFTA_BITWISE_DATA])
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return -EINVAL;
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err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &d,
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tb[NFTA_BITWISE_DATA]);
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if (err < 0)
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return err;
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if (d.type != NFT_DATA_VALUE || d.len != sizeof(u32) ||
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priv->data.data[0] >= BITS_PER_TYPE(u32)) {
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nft_data_release(&priv->data, d.type);
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return -EINVAL;
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}
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return 0;
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}
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static int nft_bitwise_init(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_bitwise *priv = nft_expr_priv(expr);
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u32 len;
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int err;
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if (!tb[NFTA_BITWISE_SREG] ||
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!tb[NFTA_BITWISE_DREG] ||
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!tb[NFTA_BITWISE_LEN])
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return -EINVAL;
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err = nft_parse_u32_check(tb[NFTA_BITWISE_LEN], U8_MAX, &len);
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if (err < 0)
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return err;
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priv->len = len;
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priv->sreg = nft_parse_register(tb[NFTA_BITWISE_SREG]);
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err = nft_validate_register_load(priv->sreg, priv->len);
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if (err < 0)
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return err;
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priv->dreg = nft_parse_register(tb[NFTA_BITWISE_DREG]);
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err = nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, priv->len);
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if (err < 0)
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return err;
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if (tb[NFTA_BITWISE_OP]) {
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priv->op = ntohl(nla_get_be32(tb[NFTA_BITWISE_OP]));
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switch (priv->op) {
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case NFT_BITWISE_BOOL:
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case NFT_BITWISE_LSHIFT:
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case NFT_BITWISE_RSHIFT:
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break;
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default:
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return -EOPNOTSUPP;
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}
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} else {
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priv->op = NFT_BITWISE_BOOL;
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}
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switch(priv->op) {
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case NFT_BITWISE_BOOL:
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err = nft_bitwise_init_bool(priv, tb);
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break;
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case NFT_BITWISE_LSHIFT:
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case NFT_BITWISE_RSHIFT:
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err = nft_bitwise_init_shift(priv, tb);
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break;
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}
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return err;
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}
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static int nft_bitwise_dump_bool(struct sk_buff *skb,
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const struct nft_bitwise *priv)
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{
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if (nft_data_dump(skb, NFTA_BITWISE_MASK, &priv->mask,
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NFT_DATA_VALUE, priv->len) < 0)
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return -1;
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if (nft_data_dump(skb, NFTA_BITWISE_XOR, &priv->xor,
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NFT_DATA_VALUE, priv->len) < 0)
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return -1;
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return 0;
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}
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static int nft_bitwise_dump_shift(struct sk_buff *skb,
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const struct nft_bitwise *priv)
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{
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if (nft_data_dump(skb, NFTA_BITWISE_DATA, &priv->data,
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NFT_DATA_VALUE, sizeof(u32)) < 0)
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return -1;
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return 0;
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}
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static int nft_bitwise_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_bitwise *priv = nft_expr_priv(expr);
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int err = 0;
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if (nft_dump_register(skb, NFTA_BITWISE_SREG, priv->sreg))
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return -1;
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if (nft_dump_register(skb, NFTA_BITWISE_DREG, priv->dreg))
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return -1;
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if (nla_put_be32(skb, NFTA_BITWISE_LEN, htonl(priv->len)))
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return -1;
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if (nla_put_be32(skb, NFTA_BITWISE_OP, htonl(priv->op)))
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return -1;
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switch (priv->op) {
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case NFT_BITWISE_BOOL:
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err = nft_bitwise_dump_bool(skb, priv);
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break;
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case NFT_BITWISE_LSHIFT:
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case NFT_BITWISE_RSHIFT:
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err = nft_bitwise_dump_shift(skb, priv);
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break;
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}
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return err;
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}
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static struct nft_data zero;
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static int nft_bitwise_offload(struct nft_offload_ctx *ctx,
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struct nft_flow_rule *flow,
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const struct nft_expr *expr)
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{
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const struct nft_bitwise *priv = nft_expr_priv(expr);
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struct nft_offload_reg *reg = &ctx->regs[priv->dreg];
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if (priv->op != NFT_BITWISE_BOOL)
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return -EOPNOTSUPP;
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if (memcmp(&priv->xor, &zero, sizeof(priv->xor)) ||
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priv->sreg != priv->dreg || priv->len != reg->len)
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return -EOPNOTSUPP;
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memcpy(®->mask, &priv->mask, sizeof(priv->mask));
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return 0;
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}
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static const struct nft_expr_ops nft_bitwise_ops = {
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.type = &nft_bitwise_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_bitwise)),
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.eval = nft_bitwise_eval,
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.init = nft_bitwise_init,
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.dump = nft_bitwise_dump,
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.offload = nft_bitwise_offload,
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};
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struct nft_expr_type nft_bitwise_type __read_mostly = {
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.name = "bitwise",
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.ops = &nft_bitwise_ops,
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.policy = nft_bitwise_policy,
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.maxattr = NFTA_BITWISE_MAX,
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.owner = THIS_MODULE,
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};
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