1 files changed, 433 insertions, 0 deletions
diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
new file mode 100644
index 000000000..963cf8317
--- /dev/null
+++ b/net/netfilter/nft_cmp.c
@@ -0,0 +1,433 @@
+// 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/if_arp.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;
+	u8			sreg;
+	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(&regs->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;
+		fallthrough;
+	case NFT_CMP_LTE:
+		if (d > 0)
+			goto mismatch;
+		break;
+	case NFT_CMP_GT:
+		if (d == 0)
+			goto mismatch;
+		fallthrough;
+	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 = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(priv->data),
+	};
+	int err;
+
+	err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]);
+	if (err < 0)
+		return err;
+
+	err = nft_parse_register_load(tb[NFTA_CMP_SREG], &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;
+}
+
+union nft_cmp_offload_data {
+	u16	val16;
+	u32	val32;
+	u64	val64;
+};
+
+static void nft_payload_n2h(union nft_cmp_offload_data *data,
+			    const u8 *val, u32 len)
+{
+	switch (len) {
+	case 2:
+		data->val16 = ntohs(*((__be16 *)val));
+		break;
+	case 4:
+		data->val32 = ntohl(*((__be32 *)val));
+		break;
+	case 8:
+		data->val64 = be64_to_cpu(*((__be64 *)val));
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
+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];
+	union nft_cmp_offload_data _data, _datamask;
+	u8 *mask = (u8 *)&flow->match.mask;
+	u8 *key = (u8 *)&flow->match.key;
+	u8 *data, *datamask;
+
+	if (priv->op != NFT_CMP_EQ || priv->len > reg->len)
+		return -EOPNOTSUPP;
+
+	if (reg->flags & NFT_OFFLOAD_F_NETWORK2HOST) {
+		nft_payload_n2h(&_data, (u8 *)&priv->data, reg->len);
+		nft_payload_n2h(&_datamask, (u8 *)&reg->mask, reg->len);
+		data = (u8 *)&_data;
+		datamask = (u8 *)&_datamask;
+	} else {
+		data = (u8 *)&priv->data;
+		datamask = (u8 *)&reg->mask;
+	}
+
+	memcpy(key + reg->offset, data, reg->len);
+	memcpy(mask + reg->offset, datamask, reg->len);
+
+	flow->match.dissector.used_keys |= BIT(reg->key);
+	flow->match.dissector.offset[reg->key] = reg->base_offset;
+
+	if (reg->key == FLOW_DISSECTOR_KEY_META &&
+	    reg->offset == offsetof(struct nft_flow_key, meta.ingress_iftype) &&
+	    nft_reg_load16(priv->data.data) != ARPHRD_ETHER)
+		return -EOPNOTSUPP;
+
+	nft_offload_update_dependency(ctx, &priv->data, reg->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,
+	.reduce		= NFT_REDUCE_READONLY,
+	.offload	= nft_cmp_offload,
+};
+
+/* Calculate the mask for the nft_cmp_fast expression. On big endian the
+ * mask needs to include the *upper* bytes when interpreting that data as
+ * something smaller than the full u32, therefore a cpu_to_le32 is done.
+ */
+static u32 nft_cmp_fast_mask(unsigned int len)
+{
+	__le32 mask = cpu_to_le32(~0U >> (sizeof_field(struct nft_cmp_fast_expr,
+					  data) * BITS_PER_BYTE - len));
+
+	return (__force u32)mask;
+}
+
+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 data;
+	struct nft_data_desc desc = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(data),
+	};
+	int err;
+
+	err = nft_data_init(NULL, &data, &desc, tb[NFTA_CMP_DATA]);
+	if (err < 0)
+		return err;
+
+	err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len);
+	if (err < 0)
+		return err;
+
+	desc.len *= BITS_PER_BYTE;
+
+	priv->mask = nft_cmp_fast_mask(desc.len);
+	priv->data = data.data[0] & priv->mask;
+	priv->len  = desc.len;
+	priv->inv  = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ;
+	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	= priv->inv ? NFT_CMP_NEQ : 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);
+	enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ;
+	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(op)))
+		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,
+	.reduce		= NFT_REDUCE_READONLY,
+	.offload	= nft_cmp_fast_offload,
+};
+
+static u32 nft_cmp_mask(u32 bitlen)
+{
+	return (__force u32)cpu_to_le32(~0U >> (sizeof(u32) * BITS_PER_BYTE - bitlen));
+}
+
+static void nft_cmp16_fast_mask(struct nft_data *data, unsigned int bitlen)
+{
+	int len = bitlen / BITS_PER_BYTE;
+	int i, words = len / sizeof(u32);
+
+	for (i = 0; i < words; i++) {
+		data->data[i] = 0xffffffff;
+		bitlen -= sizeof(u32) * BITS_PER_BYTE;
+	}
+
+	if (len % sizeof(u32))
+		data->data[i++] = nft_cmp_mask(bitlen);
+
+	for (; i < 4; i++)
+		data->data[i] = 0;
+}
+
+static int nft_cmp16_fast_init(const struct nft_ctx *ctx,
+			       const struct nft_expr *expr,
+			       const struct nlattr * const tb[])
+{
+	struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
+	struct nft_data_desc desc = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(priv->data),
+	};
+	int err;
+
+	err = nft_data_init(NULL, &priv->data, &desc, tb[NFTA_CMP_DATA]);
+	if (err < 0)
+		return err;
+
+	err = nft_parse_register_load(tb[NFTA_CMP_SREG], &priv->sreg, desc.len);
+	if (err < 0)
+		return err;
+
+	nft_cmp16_fast_mask(&priv->mask, desc.len * BITS_PER_BYTE);
+	priv->inv = ntohl(nla_get_be32(tb[NFTA_CMP_OP])) != NFT_CMP_EQ;
+	priv->len = desc.len;
+
+	return 0;
+}
+
+static int nft_cmp16_fast_offload(struct nft_offload_ctx *ctx,
+				  struct nft_flow_rule *flow,
+				  const struct nft_expr *expr)
+{
+	const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
+	struct nft_cmp_expr cmp = {
+		.data	= priv->data,
+		.sreg	= priv->sreg,
+		.len	= priv->len,
+		.op	= priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ,
+	};
+
+	return __nft_cmp_offload(ctx, flow, &cmp);
+}
+
+static int nft_cmp16_fast_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_cmp16_fast_expr *priv = nft_expr_priv(expr);
+	enum nft_cmp_ops op = priv->inv ? NFT_CMP_NEQ : NFT_CMP_EQ;
+
+	if (nft_dump_register(skb, NFTA_CMP_SREG, priv->sreg))
+		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_CMP_OP, htonl(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;
+}
+
+
+const struct nft_expr_ops nft_cmp16_fast_ops = {
+	.type		= &nft_cmp_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_cmp16_fast_expr)),
+	.eval		= NULL,	/* inlined */
+	.init		= nft_cmp16_fast_init,
+	.dump		= nft_cmp16_fast_dump,
+	.reduce		= NFT_REDUCE_READONLY,
+	.offload	= nft_cmp16_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 data;
+	struct nft_data_desc desc = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(data),
+	};
+	enum nft_cmp_ops op;
+	u8 sreg;
+	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, &desc, tb[NFTA_CMP_DATA]);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	sreg = ntohl(nla_get_be32(tb[NFTA_CMP_SREG]));
+
+	if (op == NFT_CMP_EQ || op == NFT_CMP_NEQ) {
+		if (desc.len <= sizeof(u32))
+			return &nft_cmp_fast_ops;
+		else if (desc.len <= sizeof(data) &&
+			 ((sreg >= NFT_REG_1 && sreg <= NFT_REG_4) ||
+			  (sreg >= NFT_REG32_00 && sreg <= NFT_REG32_12 && sreg % 2 == 0)))
+			return &nft_cmp16_fast_ops;
+	}
+	return &nft_cmp_ops;
+}
+
+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,
+};