/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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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struct nft_cmp_expr {
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struct nft_data data;
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enum nft_registers sreg:8;
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u8 len;
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enum nft_cmp_ops op:8;
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};
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static void nft_cmp_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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const struct nft_cmp_expr *priv = nft_expr_priv(expr);
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int d;
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d = memcmp(®s->data[priv->sreg], &priv->data, priv->len);
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switch (priv->op) {
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case NFT_CMP_EQ:
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if (d != 0)
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goto mismatch;
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break;
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case NFT_CMP_NEQ:
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if (d == 0)
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goto mismatch;
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break;
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case NFT_CMP_LT:
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if (d == 0)
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goto mismatch;
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/* fall through */
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case NFT_CMP_LTE:
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if (d > 0)
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goto mismatch;
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break;
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case NFT_CMP_GT:
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if (d == 0)
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goto mismatch;
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/* fall through */
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case NFT_CMP_GTE:
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if (d < 0)
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goto mismatch;
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break;
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}
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return;
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mismatch:
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regs->verdict.code = NFT_BREAK;
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}
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static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = {
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[NFTA_CMP_SREG] = { .type = NLA_U32 },
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[NFTA_CMP_OP] = { .type = NLA_U32 },
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[NFTA_CMP_DATA] = { .type = NLA_NESTED },
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};
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static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_cmp_expr *priv = nft_expr_priv(expr);
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struct nft_data_desc desc;
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int err;
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err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc,
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tb[NFTA_CMP_DATA]);
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if (err < 0)
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return err;
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if (desc.type != NFT_DATA_VALUE) {
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err = -EINVAL;
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nft_data_release(&priv->data, desc.type);
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return err;
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}
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priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
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err = nft_validate_register_load(priv->sreg, desc.len);
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if (err < 0)
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return err;
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priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
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priv->len = desc.len;
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return 0;
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}
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static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_cmp_expr *priv = nft_expr_priv(expr);
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if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
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goto nla_put_failure;
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if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
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NFT_DATA_VALUE, priv->len) < 0)
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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 const struct nft_expr_ops nft_cmp_ops = {
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.type = &nft_cmp_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
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.eval = nft_cmp_eval,
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.init = nft_cmp_init,
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.dump = nft_cmp_dump,
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};
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static int nft_cmp_fast_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_cmp_fast_expr *priv = nft_expr_priv(expr);
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struct nft_data_desc desc;
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struct nft_data data;
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u32 mask;
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int err;
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err = nft_data_init(NULL, &data, sizeof(data), &desc,
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tb[NFTA_CMP_DATA]);
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if (err < 0)
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return err;
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priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
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err = nft_validate_register_load(priv->sreg, desc.len);
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if (err < 0)
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return err;
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desc.len *= BITS_PER_BYTE;
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mask = nft_cmp_fast_mask(desc.len);
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priv->data = data.data[0] & mask;
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priv->len = desc.len;
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return 0;
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}
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static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
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struct nft_data data;
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if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
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goto nla_put_failure;
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if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ)))
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goto nla_put_failure;
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data.data[0] = priv->data;
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if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
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NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
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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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const struct nft_expr_ops nft_cmp_fast_ops = {
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.type = &nft_cmp_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
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.eval = NULL, /* inlined */
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.init = nft_cmp_fast_init,
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.dump = nft_cmp_fast_dump,
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};
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static const struct nft_expr_ops *
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nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
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{
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struct nft_data_desc desc;
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struct nft_data data;
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enum nft_cmp_ops op;
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int err;
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if (tb[NFTA_CMP_SREG] == NULL ||
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tb[NFTA_CMP_OP] == NULL ||
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tb[NFTA_CMP_DATA] == NULL)
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return ERR_PTR(-EINVAL);
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op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
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switch (op) {
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case NFT_CMP_EQ:
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case NFT_CMP_NEQ:
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case NFT_CMP_LT:
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case NFT_CMP_LTE:
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case NFT_CMP_GT:
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case NFT_CMP_GTE:
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break;
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default:
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return ERR_PTR(-EINVAL);
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}
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err = nft_data_init(NULL, &data, sizeof(data), &desc,
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tb[NFTA_CMP_DATA]);
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if (err < 0)
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return ERR_PTR(err);
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if (desc.type != NFT_DATA_VALUE) {
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err = -EINVAL;
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goto err1;
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}
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if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ)
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return &nft_cmp_fast_ops;
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return &nft_cmp_ops;
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err1:
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nft_data_release(&data, desc.type);
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return ERR_PTR(-EINVAL);
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}
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struct nft_expr_type nft_cmp_type __read_mostly = {
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.name = "cmp",
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.select_ops = nft_cmp_select_ops,
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.policy = nft_cmp_policy,
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.maxattr = NFTA_CMP_MAX,
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.owner = THIS_MODULE,
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};
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