Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 701 insertions, 0 deletions

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
new file mode 100644
index 000000000..c9f89f035
--- /dev/null
+++ b/net/netfilter/nft_exthdr.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ */
+
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <linux/sctp.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/sctp/sctp.h>
+#include <net/tcp.h>
+
+struct nft_exthdr {
+	u8			type;
+	u8			offset;
+	u8			len;
+	u8			op;
+	u8			dreg;
+	u8			sreg;
+	u8			flags;
+};
+
+static unsigned int optlen(const u8 *opt, unsigned int offset)
+{
+	/* Beware zero-length options: make finite progress */
+	if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
+		return 1;
+	else
+		return opt[offset + 1];
+}
+
+static int nft_skb_copy_to_reg(const struct sk_buff *skb, int offset, u32 *dest, unsigned int len)
+{
+	if (len % NFT_REG32_SIZE)
+		dest[len / NFT_REG32_SIZE] = 0;
+
+	return skb_copy_bits(skb, offset, dest, len);
+}
+
+static void nft_exthdr_ipv6_eval(const struct nft_expr *expr,
+				 struct nft_regs *regs,
+				 const struct nft_pktinfo *pkt)
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 *dest = &regs->data[priv->dreg];
+	unsigned int offset = 0;
+	int err;
+
+	if (pkt->skb->protocol != htons(ETH_P_IPV6))
+		goto err;
+
+	err = ipv6_find_hdr(pkt->skb, &offset, priv->type, NULL, NULL);
+	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
+		nft_reg_store8(dest, err >= 0);
+		return;
+	} else if (err < 0) {
+		goto err;
+	}
+	offset += priv->offset;
+
+	if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
+		goto err;
+	return;
+err:
+	regs->verdict.code = NFT_BREAK;
+}
+
+/* find the offset to specified option.
+ *
+ * If target header is found, its offset is set in *offset and return option
+ * number. Otherwise, return negative error.
+ *
+ * If the first fragment doesn't contain the End of Options it is considered
+ * invalid.
+ */
+static int ipv4_find_option(struct net *net, struct sk_buff *skb,
+			    unsigned int *offset, int target)
+{
+	unsigned char optbuf[sizeof(struct ip_options) + 40];
+	struct ip_options *opt = (struct ip_options *)optbuf;
+	struct iphdr *iph, _iph;
+	unsigned int start;
+	bool found = false;
+	__be32 info;
+	int optlen;
+
+	iph = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
+	if (!iph)
+		return -EBADMSG;
+	start = sizeof(struct iphdr);
+
+	optlen = iph->ihl * 4 - (int)sizeof(struct iphdr);
+	if (optlen <= 0)
+		return -ENOENT;
+
+	memset(opt, 0, sizeof(struct ip_options));
+	/* Copy the options since __ip_options_compile() modifies
+	 * the options.
+	 */
+	if (skb_copy_bits(skb, start, opt->__data, optlen))
+		return -EBADMSG;
+	opt->optlen = optlen;
+
+	if (__ip_options_compile(net, opt, NULL, &info))
+		return -EBADMSG;
+
+	switch (target) {
+	case IPOPT_SSRR:
+	case IPOPT_LSRR:
+		if (!opt->srr)
+			break;
+		found = target == IPOPT_SSRR ? opt->is_strictroute :
+					       !opt->is_strictroute;
+		if (found)
+			*offset = opt->srr + start;
+		break;
+	case IPOPT_RR:
+		if (!opt->rr)
+			break;
+		*offset = opt->rr + start;
+		found = true;
+		break;
+	case IPOPT_RA:
+		if (!opt->router_alert)
+			break;
+		*offset = opt->router_alert + start;
+		found = true;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return found ? target : -ENOENT;
+}
+
+static void nft_exthdr_ipv4_eval(const struct nft_expr *expr,
+				 struct nft_regs *regs,
+				 const struct nft_pktinfo *pkt)
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 *dest = &regs->data[priv->dreg];
+	struct sk_buff *skb = pkt->skb;
+	unsigned int offset;
+	int err;
+
+	if (skb->protocol != htons(ETH_P_IP))
+		goto err;
+
+	err = ipv4_find_option(nft_net(pkt), skb, &offset, priv->type);
+	if (priv->flags & NFT_EXTHDR_F_PRESENT) {
+		nft_reg_store8(dest, err >= 0);
+		return;
+	} else if (err < 0) {
+		goto err;
+	}
+	offset += priv->offset;
+
+	if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0)
+		goto err;
+	return;
+err:
+	regs->verdict.code = NFT_BREAK;
+}
+
+static void *
+nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
+		       unsigned int len, void *buffer, unsigned int *tcphdr_len)
+{
+	struct tcphdr *tcph;
+
+	if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP)
+		return NULL;
+
+	tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(*tcph), buffer);
+	if (!tcph)
+		return NULL;
+
+	*tcphdr_len = __tcp_hdrlen(tcph);
+	if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len)
+		return NULL;
+
+	return skb_header_pointer(pkt->skb, nft_thoff(pkt), *tcphdr_len, buffer);
+}
+
+static void nft_exthdr_tcp_eval(const struct nft_expr *expr,
+				struct nft_regs *regs,
+				const struct nft_pktinfo *pkt)
+{
+	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	unsigned int i, optl, tcphdr_len, offset;
+	u32 *dest = &regs->data[priv->dreg];
+	struct tcphdr *tcph;
+	u8 *opt;
+
+	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+	if (!tcph)
+		goto err;
+
+	opt = (u8 *)tcph;
+	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
+		optl = optlen(opt, i);
+
+		if (priv->type != opt[i])
+			continue;
+
+		if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
+			goto err;
+
+		offset = i + priv->offset;
+		if (priv->flags & NFT_EXTHDR_F_PRESENT) {
+			nft_reg_store8(dest, 1);
+		} else {
+			if (priv->len % NFT_REG32_SIZE)
+				dest[priv->len / NFT_REG32_SIZE] = 0;
+			memcpy(dest, opt + offset, priv->len);
+		}
+
+		return;
+	}
+
+err:
+	if (priv->flags & NFT_EXTHDR_F_PRESENT)
+		*dest = 0;
+	else
+		regs->verdict.code = NFT_BREAK;
+}
+
+static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
+				    struct nft_regs *regs,
+				    const struct nft_pktinfo *pkt)
+{
+	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	unsigned int i, optl, tcphdr_len, offset;
+	struct tcphdr *tcph;
+	u8 *opt;
+
+	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+	if (!tcph)
+		goto err;
+
+	if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len))
+		goto err;
+
+	tcph = (struct tcphdr *)(pkt->skb->data + nft_thoff(pkt));
+	opt = (u8 *)tcph;
+
+	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
+		union {
+			__be16 v16;
+			__be32 v32;
+		} old, new;
+
+		optl = optlen(opt, i);
+
+		if (priv->type != opt[i])
+			continue;
+
+		if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
+			goto err;
+
+		offset = i + priv->offset;
+
+		switch (priv->len) {
+		case 2:
+			old.v16 = get_unaligned((u16 *)(opt + offset));
+			new.v16 = (__force __be16)nft_reg_load16(
+				&regs->data[priv->sreg]);
+
+			switch (priv->type) {
+			case TCPOPT_MSS:
+				/* increase can cause connection to stall */
+				if (ntohs(old.v16) <= ntohs(new.v16))
+					return;
+			break;
+			}
+
+			if (old.v16 == new.v16)
+				return;
+
+			put_unaligned(new.v16, (u16*)(opt + offset));
+			inet_proto_csum_replace2(&tcph->check, pkt->skb,
+						 old.v16, new.v16, false);
+			break;
+		case 4:
+			new.v32 = regs->data[priv->sreg];
+			old.v32 = get_unaligned((u32 *)(opt + offset));
+
+			if (old.v32 == new.v32)
+				return;
+
+			put_unaligned(new.v32, (u32*)(opt + offset));
+			inet_proto_csum_replace4(&tcph->check, pkt->skb,
+						 old.v32, new.v32, false);
+			break;
+		default:
+			WARN_ON_ONCE(1);
+			break;
+		}
+
+		return;
+	}
+	return;
+err:
+	regs->verdict.code = NFT_BREAK;
+}
+
+static void nft_exthdr_tcp_strip_eval(const struct nft_expr *expr,
+				      struct nft_regs *regs,
+				      const struct nft_pktinfo *pkt)
+{
+	u8 buff[sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE];
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	unsigned int i, tcphdr_len, optl;
+	struct tcphdr *tcph;
+	u8 *opt;
+
+	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
+	if (!tcph)
+		goto err;
+
+	if (skb_ensure_writable(pkt->skb, nft_thoff(pkt) + tcphdr_len))
+		goto drop;
+
+	tcph = (struct tcphdr *)(pkt->skb->data + nft_thoff(pkt));
+	opt = (u8 *)tcph;
+
+	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
+		unsigned int j;
+
+		optl = optlen(opt, i);
+		if (priv->type != opt[i])
+			continue;
+
+		if (i + optl > tcphdr_len)
+			goto drop;
+
+		for (j = 0; j < optl; ++j) {
+			u16 n = TCPOPT_NOP;
+			u16 o = opt[i+j];
+
+			if ((i + j) % 2 == 0) {
+				o <<= 8;
+				n <<= 8;
+			}
+			inet_proto_csum_replace2(&tcph->check, pkt->skb, htons(o),
+						 htons(n), false);
+		}
+		memset(opt + i, TCPOPT_NOP, optl);
+		return;
+	}
+
+	/* option not found, continue. This allows to do multiple
+	 * option removals per rule.
+	 */
+	return;
+err:
+	regs->verdict.code = NFT_BREAK;
+	return;
+drop:
+	/* can't remove, no choice but to drop */
+	regs->verdict.code = NF_DROP;
+}
+
+static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
+				 struct nft_regs *regs,
+				 const struct nft_pktinfo *pkt)
+{
+	unsigned int offset = nft_thoff(pkt) + sizeof(struct sctphdr);
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 *dest = &regs->data[priv->dreg];
+	const struct sctp_chunkhdr *sch;
+	struct sctp_chunkhdr _sch;
+
+	if (pkt->tprot != IPPROTO_SCTP)
+		goto err;
+
+	do {
+		sch = skb_header_pointer(pkt->skb, offset, sizeof(_sch), &_sch);
+		if (!sch || !sch->length)
+			break;
+
+		if (sch->type == priv->type) {
+			if (priv->flags & NFT_EXTHDR_F_PRESENT) {
+				nft_reg_store8(dest, true);
+				return;
+			}
+			if (priv->offset + priv->len > ntohs(sch->length) ||
+			    offset + ntohs(sch->length) > pkt->skb->len)
+				break;
+
+			if (nft_skb_copy_to_reg(pkt->skb, offset + priv->offset,
+						dest, priv->len) < 0)
+				break;
+			return;
+		}
+		offset += SCTP_PAD4(ntohs(sch->length));
+	} while (offset < pkt->skb->len);
+err:
+	if (priv->flags & NFT_EXTHDR_F_PRESENT)
+		nft_reg_store8(dest, false);
+	else
+		regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_exthdr_policy[NFTA_EXTHDR_MAX + 1] = {
+	[NFTA_EXTHDR_DREG]		= { .type = NLA_U32 },
+	[NFTA_EXTHDR_TYPE]		= { .type = NLA_U8 },
+	[NFTA_EXTHDR_OFFSET]		= { .type = NLA_U32 },
+	[NFTA_EXTHDR_LEN]		= { .type = NLA_U32 },
+	[NFTA_EXTHDR_FLAGS]		= { .type = NLA_U32 },
+	[NFTA_EXTHDR_OP]		= { .type = NLA_U32 },
+	[NFTA_EXTHDR_SREG]		= { .type = NLA_U32 },
+};
+
+static int nft_exthdr_init(const struct nft_ctx *ctx,
+			   const struct nft_expr *expr,
+			   const struct nlattr * const tb[])
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
+	int err;
+
+	if (!tb[NFTA_EXTHDR_DREG] ||
+	    !tb[NFTA_EXTHDR_TYPE] ||
+	    !tb[NFTA_EXTHDR_OFFSET] ||
+	    !tb[NFTA_EXTHDR_LEN])
+		return -EINVAL;
+
+	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
+	if (err < 0)
+		return err;
+
+	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
+	if (err < 0)
+		return err;
+
+	if (tb[NFTA_EXTHDR_FLAGS]) {
+		err = nft_parse_u32_check(tb[NFTA_EXTHDR_FLAGS], U8_MAX, &flags);
+		if (err < 0)
+			return err;
+
+		if (flags & ~NFT_EXTHDR_F_PRESENT)
+			return -EINVAL;
+	}
+
+	if (tb[NFTA_EXTHDR_OP]) {
+		err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
+		if (err < 0)
+			return err;
+	}
+
+	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
+	priv->offset = offset;
+	priv->len    = len;
+	priv->flags  = flags;
+	priv->op     = op;
+
+	return nft_parse_register_store(ctx, tb[NFTA_EXTHDR_DREG],
+					&priv->dreg, NULL, NFT_DATA_VALUE,
+					priv->len);
+}
+
+static int nft_exthdr_tcp_set_init(const struct nft_ctx *ctx,
+				   const struct nft_expr *expr,
+				   const struct nlattr * const tb[])
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	u32 offset, len, flags = 0, op = NFT_EXTHDR_OP_IPV6;
+	int err;
+
+	if (!tb[NFTA_EXTHDR_SREG] ||
+	    !tb[NFTA_EXTHDR_TYPE] ||
+	    !tb[NFTA_EXTHDR_OFFSET] ||
+	    !tb[NFTA_EXTHDR_LEN])
+		return -EINVAL;
+
+	if (tb[NFTA_EXTHDR_DREG] || tb[NFTA_EXTHDR_FLAGS])
+		return -EINVAL;
+
+	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OFFSET], U8_MAX, &offset);
+	if (err < 0)
+		return err;
+
+	err = nft_parse_u32_check(tb[NFTA_EXTHDR_LEN], U8_MAX, &len);
+	if (err < 0)
+		return err;
+
+	if (offset < 2)
+		return -EOPNOTSUPP;
+
+	switch (len) {
+	case 2: break;
+	case 4: break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = nft_parse_u32_check(tb[NFTA_EXTHDR_OP], U8_MAX, &op);
+	if (err < 0)
+		return err;
+
+	priv->type   = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
+	priv->offset = offset;
+	priv->len    = len;
+	priv->flags  = flags;
+	priv->op     = op;
+
+	return nft_parse_register_load(tb[NFTA_EXTHDR_SREG], &priv->sreg,
+				       priv->len);
+}
+
+static int nft_exthdr_tcp_strip_init(const struct nft_ctx *ctx,
+				     const struct nft_expr *expr,
+				     const struct nlattr * const tb[])
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+
+	if (tb[NFTA_EXTHDR_SREG] ||
+	    tb[NFTA_EXTHDR_DREG] ||
+	    tb[NFTA_EXTHDR_FLAGS] ||
+	    tb[NFTA_EXTHDR_OFFSET] ||
+	    tb[NFTA_EXTHDR_LEN])
+		return -EINVAL;
+
+	if (!tb[NFTA_EXTHDR_TYPE])
+		return -EINVAL;
+
+	priv->type = nla_get_u8(tb[NFTA_EXTHDR_TYPE]);
+	priv->op = NFT_EXTHDR_OP_TCPOPT;
+
+	return 0;
+}
+
+static int nft_exthdr_ipv4_init(const struct nft_ctx *ctx,
+				const struct nft_expr *expr,
+				const struct nlattr * const tb[])
+{
+	struct nft_exthdr *priv = nft_expr_priv(expr);
+	int err = nft_exthdr_init(ctx, expr, tb);
+
+	if (err < 0)
+		return err;
+
+	switch (priv->type) {
+	case IPOPT_SSRR:
+	case IPOPT_LSRR:
+	case IPOPT_RR:
+	case IPOPT_RA:
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int nft_exthdr_dump_common(struct sk_buff *skb, const struct nft_exthdr *priv)
+{
+	if (nla_put_u8(skb, NFTA_EXTHDR_TYPE, priv->type))
+		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_EXTHDR_OFFSET, htonl(priv->offset)))
+		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_EXTHDR_LEN, htonl(priv->len)))
+		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_EXTHDR_FLAGS, htonl(priv->flags)))
+		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_EXTHDR_OP, htonl(priv->op)))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static int nft_exthdr_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_exthdr *priv = nft_expr_priv(expr);
+
+	if (nft_dump_register(skb, NFTA_EXTHDR_DREG, priv->dreg))
+		return -1;
+
+	return nft_exthdr_dump_common(skb, priv);
+}
+
+static int nft_exthdr_dump_set(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_exthdr *priv = nft_expr_priv(expr);
+
+	if (nft_dump_register(skb, NFTA_EXTHDR_SREG, priv->sreg))
+		return -1;
+
+	return nft_exthdr_dump_common(skb, priv);
+}
+
+static int nft_exthdr_dump_strip(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_exthdr *priv = nft_expr_priv(expr);
+
+	return nft_exthdr_dump_common(skb, priv);
+}
+
+static const struct nft_expr_ops nft_exthdr_ipv6_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_ipv6_eval,
+	.init		= nft_exthdr_init,
+	.dump		= nft_exthdr_dump,
+};
+
+static const struct nft_expr_ops nft_exthdr_ipv4_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_ipv4_eval,
+	.init		= nft_exthdr_ipv4_init,
+	.dump		= nft_exthdr_dump,
+};
+
+static const struct nft_expr_ops nft_exthdr_tcp_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_tcp_eval,
+	.init		= nft_exthdr_init,
+	.dump		= nft_exthdr_dump,
+};
+
+static const struct nft_expr_ops nft_exthdr_tcp_set_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_tcp_set_eval,
+	.init		= nft_exthdr_tcp_set_init,
+	.dump		= nft_exthdr_dump_set,
+};
+
+static const struct nft_expr_ops nft_exthdr_tcp_strip_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_tcp_strip_eval,
+	.init		= nft_exthdr_tcp_strip_init,
+	.dump		= nft_exthdr_dump_strip,
+};
+
+static const struct nft_expr_ops nft_exthdr_sctp_ops = {
+	.type		= &nft_exthdr_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
+	.eval		= nft_exthdr_sctp_eval,
+	.init		= nft_exthdr_init,
+	.dump		= nft_exthdr_dump,
+};
+
+static const struct nft_expr_ops *
+nft_exthdr_select_ops(const struct nft_ctx *ctx,
+		      const struct nlattr * const tb[])
+{
+	u32 op;
+
+	if (!tb[NFTA_EXTHDR_OP])
+		return &nft_exthdr_ipv6_ops;
+
+	if (tb[NFTA_EXTHDR_SREG] && tb[NFTA_EXTHDR_DREG])
+		return ERR_PTR(-EOPNOTSUPP);
+
+	op = ntohl(nla_get_be32(tb[NFTA_EXTHDR_OP]));
+	switch (op) {
+	case NFT_EXTHDR_OP_TCPOPT:
+		if (tb[NFTA_EXTHDR_SREG])
+			return &nft_exthdr_tcp_set_ops;
+		if (tb[NFTA_EXTHDR_DREG])
+			return &nft_exthdr_tcp_ops;
+		return &nft_exthdr_tcp_strip_ops;
+	case NFT_EXTHDR_OP_IPV6:
+		if (tb[NFTA_EXTHDR_DREG])
+			return &nft_exthdr_ipv6_ops;
+		break;
+	case NFT_EXTHDR_OP_IPV4:
+		if (ctx->family != NFPROTO_IPV6) {
+			if (tb[NFTA_EXTHDR_DREG])
+				return &nft_exthdr_ipv4_ops;
+		}
+		break;
+	case NFT_EXTHDR_OP_SCTP:
+		if (tb[NFTA_EXTHDR_DREG])
+			return &nft_exthdr_sctp_ops;
+		break;
+	}
+
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+struct nft_expr_type nft_exthdr_type __read_mostly = {
+	.name		= "exthdr",
+	.select_ops	= nft_exthdr_select_ops,
+	.policy		= nft_exthdr_policy,
+	.maxattr	= NFTA_EXTHDR_MAX,
+	.owner		= THIS_MODULE,
+};