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https://github.com/brain-hackers/linux-brain.git
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28b1d6ef53
The rule below doesn't work as the kernel raises -ERANGE.
nft add rule netdev nftlb lb01 ip daddr set \
symhash mod 1 map { 0 : 192.168.0.10 } fwd to "eth0"
This patch allows to use the symhash modulus with one
element, in the same way that the other types of hashes and
algorithms that uses the modulus parameter.
Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
251 lines
6.2 KiB
C
251 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2016 Laura Garcia <nevola@gmail.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.h>
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#include <net/netfilter/nf_tables_core.h>
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#include <linux/jhash.h>
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struct nft_jhash {
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enum nft_registers sreg:8;
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enum nft_registers dreg:8;
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u8 len;
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bool autogen_seed:1;
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u32 modulus;
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u32 seed;
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u32 offset;
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};
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static void nft_jhash_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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struct nft_jhash *priv = nft_expr_priv(expr);
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const void *data = ®s->data[priv->sreg];
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u32 h;
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h = reciprocal_scale(jhash(data, priv->len, priv->seed),
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priv->modulus);
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regs->data[priv->dreg] = h + priv->offset;
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}
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struct nft_symhash {
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enum nft_registers dreg:8;
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u32 modulus;
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u32 offset;
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};
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static void nft_symhash_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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struct nft_symhash *priv = nft_expr_priv(expr);
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struct sk_buff *skb = pkt->skb;
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u32 h;
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h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
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regs->data[priv->dreg] = h + priv->offset;
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}
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static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
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[NFTA_HASH_SREG] = { .type = NLA_U32 },
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[NFTA_HASH_DREG] = { .type = NLA_U32 },
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[NFTA_HASH_LEN] = { .type = NLA_U32 },
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[NFTA_HASH_MODULUS] = { .type = NLA_U32 },
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[NFTA_HASH_SEED] = { .type = NLA_U32 },
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[NFTA_HASH_OFFSET] = { .type = NLA_U32 },
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[NFTA_HASH_TYPE] = { .type = NLA_U32 },
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};
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static int nft_jhash_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_jhash *priv = nft_expr_priv(expr);
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u32 len;
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int err;
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if (!tb[NFTA_HASH_SREG] ||
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!tb[NFTA_HASH_DREG] ||
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!tb[NFTA_HASH_LEN] ||
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!tb[NFTA_HASH_MODULUS])
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return -EINVAL;
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if (tb[NFTA_HASH_OFFSET])
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priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
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priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
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priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
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err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
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if (err < 0)
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return err;
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if (len == 0)
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return -ERANGE;
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priv->len = len;
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priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
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if (priv->modulus < 1)
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return -ERANGE;
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if (priv->offset + priv->modulus - 1 < priv->offset)
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return -EOVERFLOW;
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if (tb[NFTA_HASH_SEED]) {
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priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
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} else {
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priv->autogen_seed = true;
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get_random_bytes(&priv->seed, sizeof(priv->seed));
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}
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return nft_validate_register_load(priv->sreg, len) &&
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nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, sizeof(u32));
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}
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static int nft_symhash_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_symhash *priv = nft_expr_priv(expr);
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if (!tb[NFTA_HASH_DREG] ||
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!tb[NFTA_HASH_MODULUS])
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return -EINVAL;
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if (tb[NFTA_HASH_OFFSET])
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priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
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priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
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priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
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if (priv->modulus < 1)
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return -ERANGE;
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if (priv->offset + priv->modulus - 1 < priv->offset)
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return -EOVERFLOW;
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return nft_validate_register_store(ctx, priv->dreg, NULL,
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NFT_DATA_VALUE, sizeof(u32));
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}
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static int nft_jhash_dump(struct sk_buff *skb,
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const struct nft_expr *expr)
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{
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const struct nft_jhash *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
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goto nla_put_failure;
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if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
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goto nla_put_failure;
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if (!priv->autogen_seed &&
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nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
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goto nla_put_failure;
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if (priv->offset != 0)
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if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static int nft_symhash_dump(struct sk_buff *skb,
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const struct nft_expr *expr)
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{
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const struct nft_symhash *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
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goto nla_put_failure;
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if (priv->offset != 0)
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if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -1;
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}
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static struct nft_expr_type nft_hash_type;
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static const struct nft_expr_ops nft_jhash_ops = {
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.type = &nft_hash_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
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.eval = nft_jhash_eval,
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.init = nft_jhash_init,
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.dump = nft_jhash_dump,
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};
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static const struct nft_expr_ops nft_symhash_ops = {
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.type = &nft_hash_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
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.eval = nft_symhash_eval,
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.init = nft_symhash_init,
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.dump = nft_symhash_dump,
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};
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static const struct nft_expr_ops *
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nft_hash_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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u32 type;
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if (!tb[NFTA_HASH_TYPE])
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return &nft_jhash_ops;
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type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
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switch (type) {
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case NFT_HASH_SYM:
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return &nft_symhash_ops;
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case NFT_HASH_JENKINS:
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return &nft_jhash_ops;
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default:
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break;
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}
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return ERR_PTR(-EOPNOTSUPP);
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}
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static struct nft_expr_type nft_hash_type __read_mostly = {
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.name = "hash",
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.select_ops = nft_hash_select_ops,
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.policy = nft_hash_policy,
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.maxattr = NFTA_HASH_MAX,
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.owner = THIS_MODULE,
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};
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static int __init nft_hash_module_init(void)
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{
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return nft_register_expr(&nft_hash_type);
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}
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static void __exit nft_hash_module_exit(void)
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{
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nft_unregister_expr(&nft_hash_type);
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}
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module_init(nft_hash_module_init);
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module_exit(nft_hash_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
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MODULE_ALIAS_NFT_EXPR("hash");
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