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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables_offload.h>
#include <net/netfilter/nf_tables.h>
struct nft_cmp_expr {
struct nft_data data;
enum nft_registers sreg:8;
u8 len;
enum nft_cmp_ops op:8;
};
void nft_cmp_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
int d;
d = memcmp(®s->data[priv->sreg], &priv->data, priv->len);
switch (priv->op) {
case NFT_CMP_EQ:
if (d != 0)
goto mismatch;
break;
case NFT_CMP_NEQ:
if (d == 0)
goto mismatch;
break;
case NFT_CMP_LT:
if (d == 0)
goto mismatch;
/* fall through */
case NFT_CMP_LTE:
if (d > 0)
goto mismatch;
break;
case NFT_CMP_GT:
if (d == 0)
goto mismatch;
/* fall through */
case NFT_CMP_GTE:
if (d < 0)
goto mismatch;
break;
}
return;
mismatch:
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_cmp_policy[NFTA_CMP_MAX + 1] = {
[NFTA_CMP_SREG] = { .type = NLA_U32 },
[NFTA_CMP_OP] = { .type = NLA_U32 },
[NFTA_CMP_DATA] = { .type = NLA_NESTED },
};
static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_cmp_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc;
int err;
err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return err;
priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
err = nft_validate_register_load(priv->sreg, desc.len);
if (err < 0)
return err;
priv->op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
priv->len = desc.len;
return 0;
}
static int nft_cmp_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_CMP_OP, htonl(priv->op)))
goto nla_put_failure;
if (nft_data_dump(skb, NFTA_CMP_DATA, &priv->data,
NFT_DATA_VALUE, priv->len) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static int __nft_cmp_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_cmp_expr *priv)
{
struct nft_offload_reg *reg = &ctx->regs[priv->sreg];
u8 *mask = (u8 *)&flow->match.mask;
u8 *key = (u8 *)&flow->match.key;
if (priv->op != NFT_CMP_EQ)
return -EOPNOTSUPP;
memcpy(key + reg->offset, &priv->data, priv->len);
memcpy(mask + reg->offset, ®->mask, priv->len);
flow->match.dissector.used_keys |= BIT(reg->key);
flow->match.dissector.offset[reg->key] = reg->base_offset;
nft_offload_update_dependency(ctx, &priv->data, priv->len);
return 0;
}
static int nft_cmp_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_expr *expr)
{
const struct nft_cmp_expr *priv = nft_expr_priv(expr);
return __nft_cmp_offload(ctx, flow, priv);
}
static const struct nft_expr_ops nft_cmp_ops = {
.type = &nft_cmp_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_expr)),
.eval = nft_cmp_eval,
.init = nft_cmp_init,
.dump = nft_cmp_dump,
.offload = nft_cmp_offload,
};
static int nft_cmp_fast_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
struct nft_data_desc desc;
struct nft_data data;
u32 mask;
int err;
err = nft_data_init(NULL, &data, sizeof(data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return err;
priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
err = nft_validate_register_load(priv->sreg, desc.len);
if (err < 0)
return err;
desc.len *= BITS_PER_BYTE;
mask = nft_cmp_fast_mask(desc.len);
priv->data = data.data[0] & mask;
priv->len = desc.len;
return 0;
}
static int nft_cmp_fast_offload(struct nft_offload_ctx *ctx,
struct nft_flow_rule *flow,
const struct nft_expr *expr)
{
const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
struct nft_cmp_expr cmp = {
.data = {
.data = {
[0] = priv->data,
},
},
.sreg = priv->sreg,
.len = priv->len / BITS_PER_BYTE,
.op = NFT_CMP_EQ,
};
return __nft_cmp_offload(ctx, flow, &cmp);
}
static int nft_cmp_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
struct nft_data data;
if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
goto nla_put_failure;
if (nla_put_be32(skb, NFTA_CMP_OP, htonl(NFT_CMP_EQ)))
goto nla_put_failure;
data.data[0] = priv->data;
if (nft_data_dump(skb, NFTA_CMP_DATA, &data,
NFT_DATA_VALUE, priv->len / BITS_PER_BYTE) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
const struct nft_expr_ops nft_cmp_fast_ops = {
.type = &nft_cmp_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_cmp_fast_expr)),
.eval = NULL, /* inlined */
.init = nft_cmp_fast_init,
.dump = nft_cmp_fast_dump,
.offload = nft_cmp_fast_offload,
};
static const struct nft_expr_ops *
nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
{
struct nft_data_desc desc;
struct nft_data data;
enum nft_cmp_ops op;
int err;
if (tb[NFTA_CMP_SREG] == NULL ||
tb[NFTA_CMP_OP] == NULL ||
tb[NFTA_CMP_DATA] == NULL)
return ERR_PTR(-EINVAL);
op = ntohl(nla_get_be32(tb[NFTA_CMP_OP]));
switch (op) {
case NFT_CMP_EQ:
case NFT_CMP_NEQ:
case NFT_CMP_LT:
case NFT_CMP_LTE:
case NFT_CMP_GT:
case NFT_CMP_GTE:
break;
default:
return ERR_PTR(-EINVAL);
}
err = nft_data_init(NULL, &data, sizeof(data), &desc,
tb[NFTA_CMP_DATA]);
if (err < 0)
return ERR_PTR(err);
if (desc.type != NFT_DATA_VALUE) {
err = -EINVAL;
goto err1;
}
if (desc.len <= sizeof(u32) && op == NFT_CMP_EQ)
return &nft_cmp_fast_ops;
return &nft_cmp_ops;
err1:
nft_data_release(&data, desc.type);
return ERR_PTR(-EINVAL);
}
struct nft_expr_type nft_cmp_type __read_mostly = {
.name = "cmp",
.select_ops = nft_cmp_select_ops,
.policy = nft_cmp_policy,
.maxattr = NFTA_CMP_MAX,
.owner = THIS_MODULE,
};
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