Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 909 insertions, 0 deletions

diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
new file mode 100644
index 000000000..9a5e79a38
--- /dev/null
+++ b/net/xfrm/xfrm_output.c
@@ -0,0 +1,909 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * xfrm_output.c - Common IPsec encapsulation code.
+ *
+ * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
+ */
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/netfilter.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <net/dst.h>
+#include <net/icmp.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ip6_route.h>
+#include <net/ipv6_stubs.h>
+#endif
+
+#include "xfrm_inout.h"
+
+static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
+static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
+
+static int xfrm_skb_check_space(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
+		- skb_headroom(skb);
+	int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
+
+	if (nhead <= 0) {
+		if (ntail <= 0)
+			return 0;
+		nhead = 0;
+	} else if (ntail < 0)
+		ntail = 0;
+
+	return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
+}
+
+/* Children define the path of the packet through the
+ * Linux networking.  Thus, destinations are stackable.
+ */
+
+static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
+{
+	struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
+
+	skb_dst_drop(skb);
+	return child;
+}
+
+/* Add encapsulation header.
+ *
+ * The IP header will be moved forward to make space for the encapsulation
+ * header.
+ */
+static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct iphdr *iph = ip_hdr(skb);
+	int ihl = iph->ihl * 4;
+
+	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+
+	skb_set_network_header(skb, -x->props.header_len);
+	skb->mac_header = skb->network_header +
+			  offsetof(struct iphdr, protocol);
+	skb->transport_header = skb->network_header + ihl;
+	__skb_pull(skb, ihl);
+	memmove(skb_network_header(skb), iph, ihl);
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
+{
+	const unsigned char *nh = skb_network_header(skb);
+	unsigned int offset = sizeof(struct ipv6hdr);
+	unsigned int packet_len;
+	int found_rhdr = 0;
+
+	packet_len = skb_tail_pointer(skb) - nh;
+	*nexthdr = &ipv6_hdr(skb)->nexthdr;
+
+	while (offset <= packet_len) {
+		struct ipv6_opt_hdr *exthdr;
+
+		switch (**nexthdr) {
+		case NEXTHDR_HOP:
+			break;
+		case NEXTHDR_ROUTING:
+			if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
+				struct ipv6_rt_hdr *rt;
+
+				rt = (struct ipv6_rt_hdr *)(nh + offset);
+				if (rt->type != 0)
+					return offset;
+			}
+			found_rhdr = 1;
+			break;
+		case NEXTHDR_DEST:
+			/* HAO MUST NOT appear more than once.
+			 * XXX: It is better to try to find by the end of
+			 * XXX: packet if HAO exists.
+			 */
+			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
+				net_dbg_ratelimited("mip6: hao exists already, override\n");
+				return offset;
+			}
+
+			if (found_rhdr)
+				return offset;
+
+			break;
+		default:
+			return offset;
+		}
+
+		if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
+			return -EINVAL;
+
+		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
+						 offset);
+		offset += ipv6_optlen(exthdr);
+		if (offset > IPV6_MAXPLEN)
+			return -EINVAL;
+		*nexthdr = &exthdr->nexthdr;
+	}
+
+	return -EINVAL;
+}
+#endif
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
+{
+	switch (x->type->proto) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+	case IPPROTO_DSTOPTS:
+	case IPPROTO_ROUTING:
+		return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
+#endif
+	default:
+		break;
+	}
+
+	return ip6_find_1stfragopt(skb, prevhdr);
+}
+#endif
+
+/* Add encapsulation header.
+ *
+ * The IP header and mutable extension headers will be moved forward to make
+ * space for the encapsulation header.
+ */
+static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	struct ipv6hdr *iph;
+	u8 *prevhdr;
+	int hdr_len;
+
+	iph = ipv6_hdr(skb);
+	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+
+	hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
+	if (hdr_len < 0)
+		return hdr_len;
+	skb_set_mac_header(skb,
+			   (prevhdr - x->props.header_len) - skb->data);
+	skb_set_network_header(skb, -x->props.header_len);
+	skb->transport_header = skb->network_header + hdr_len;
+	__skb_pull(skb, hdr_len);
+	memmove(ipv6_hdr(skb), iph, hdr_len);
+	return 0;
+#else
+	WARN_ON_ONCE(1);
+	return -EAFNOSUPPORT;
+#endif
+}
+
+/* Add route optimization header space.
+ *
+ * The IP header and mutable extension headers will be moved forward to make
+ * space for the route optimization header.
+ */
+static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	struct ipv6hdr *iph;
+	u8 *prevhdr;
+	int hdr_len;
+
+	iph = ipv6_hdr(skb);
+
+	hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
+	if (hdr_len < 0)
+		return hdr_len;
+	skb_set_mac_header(skb,
+			   (prevhdr - x->props.header_len) - skb->data);
+	skb_set_network_header(skb, -x->props.header_len);
+	skb->transport_header = skb->network_header + hdr_len;
+	__skb_pull(skb, hdr_len);
+	memmove(ipv6_hdr(skb), iph, hdr_len);
+
+	x->lastused = ktime_get_real_seconds();
+
+	return 0;
+#else
+	WARN_ON_ONCE(1);
+	return -EAFNOSUPPORT;
+#endif
+}
+
+/* Add encapsulation header.
+ *
+ * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
+ */
+static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct ip_beet_phdr *ph;
+	struct iphdr *top_iph;
+	int hdrlen, optlen;
+
+	hdrlen = 0;
+	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
+	if (unlikely(optlen))
+		hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
+
+	skb_set_network_header(skb, -x->props.header_len - hdrlen +
+			       (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
+	if (x->sel.family != AF_INET6)
+		skb->network_header += IPV4_BEET_PHMAXLEN;
+	skb->mac_header = skb->network_header +
+			  offsetof(struct iphdr, protocol);
+	skb->transport_header = skb->network_header + sizeof(*top_iph);
+
+	xfrm4_beet_make_header(skb);
+
+	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
+
+	top_iph = ip_hdr(skb);
+
+	if (unlikely(optlen)) {
+		if (WARN_ON(optlen < 0))
+			return -EINVAL;
+
+		ph->padlen = 4 - (optlen & 4);
+		ph->hdrlen = optlen / 8;
+		ph->nexthdr = top_iph->protocol;
+		if (ph->padlen)
+			memset(ph + 1, IPOPT_NOP, ph->padlen);
+
+		top_iph->protocol = IPPROTO_BEETPH;
+		top_iph->ihl = sizeof(struct iphdr) / 4;
+	}
+
+	top_iph->saddr = x->props.saddr.a4;
+	top_iph->daddr = x->id.daddr.a4;
+
+	return 0;
+}
+
+/* Add encapsulation header.
+ *
+ * The top IP header will be constructed per RFC 2401.
+ */
+static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
+{
+	bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
+	struct dst_entry *dst = skb_dst(skb);
+	struct iphdr *top_iph;
+	int flags;
+
+	skb_set_inner_network_header(skb, skb_network_offset(skb));
+	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+
+	skb_set_network_header(skb, -x->props.header_len);
+	skb->mac_header = skb->network_header +
+			  offsetof(struct iphdr, protocol);
+	skb->transport_header = skb->network_header + sizeof(*top_iph);
+	top_iph = ip_hdr(skb);
+
+	top_iph->ihl = 5;
+	top_iph->version = 4;
+
+	top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
+
+	/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
+	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
+		top_iph->tos = 0;
+	else
+		top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
+	top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
+					    XFRM_MODE_SKB_CB(skb)->tos);
+
+	flags = x->props.flags;
+	if (flags & XFRM_STATE_NOECN)
+		IP_ECN_clear(top_iph);
+
+	top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
+		0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
+
+	top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
+
+	top_iph->saddr = x->props.saddr.a4;
+	top_iph->daddr = x->id.daddr.a4;
+	ip_select_ident(dev_net(dst->dev), skb, NULL);
+
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct ipv6hdr *top_iph;
+	int dsfield;
+
+	skb_set_inner_network_header(skb, skb_network_offset(skb));
+	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+
+	skb_set_network_header(skb, -x->props.header_len);
+	skb->mac_header = skb->network_header +
+			  offsetof(struct ipv6hdr, nexthdr);
+	skb->transport_header = skb->network_header + sizeof(*top_iph);
+	top_iph = ipv6_hdr(skb);
+
+	top_iph->version = 6;
+
+	memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
+	       sizeof(top_iph->flow_lbl));
+	top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
+
+	if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
+		dsfield = 0;
+	else
+		dsfield = XFRM_MODE_SKB_CB(skb)->tos;
+	dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
+	if (x->props.flags & XFRM_STATE_NOECN)
+		dsfield &= ~INET_ECN_MASK;
+	ipv6_change_dsfield(top_iph, 0, dsfield);
+	top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
+	top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
+	top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
+	return 0;
+}
+
+static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct ipv6hdr *top_iph;
+	struct ip_beet_phdr *ph;
+	int optlen, hdr_len;
+
+	hdr_len = 0;
+	optlen = XFRM_MODE_SKB_CB(skb)->optlen;
+	if (unlikely(optlen))
+		hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
+
+	skb_set_network_header(skb, -x->props.header_len - hdr_len);
+	if (x->sel.family != AF_INET6)
+		skb->network_header += IPV4_BEET_PHMAXLEN;
+	skb->mac_header = skb->network_header +
+			  offsetof(struct ipv6hdr, nexthdr);
+	skb->transport_header = skb->network_header + sizeof(*top_iph);
+	ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
+
+	xfrm6_beet_make_header(skb);
+
+	top_iph = ipv6_hdr(skb);
+	if (unlikely(optlen)) {
+		if (WARN_ON(optlen < 0))
+			return -EINVAL;
+
+		ph->padlen = 4 - (optlen & 4);
+		ph->hdrlen = optlen / 8;
+		ph->nexthdr = top_iph->nexthdr;
+		if (ph->padlen)
+			memset(ph + 1, IPOPT_NOP, ph->padlen);
+
+		top_iph->nexthdr = IPPROTO_BEETPH;
+	}
+
+	top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
+	top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
+	return 0;
+}
+#endif
+
+/* Add encapsulation header.
+ *
+ * On exit, the transport header will be set to the start of the
+ * encapsulation header to be filled in by x->type->output and the mac
+ * header will be set to the nextheader (protocol for IPv4) field of the
+ * extension header directly preceding the encapsulation header, or in
+ * its absence, that of the top IP header.
+ * The value of the network header will always point to the top IP header
+ * while skb->data will point to the payload.
+ */
+static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int err;
+
+	err = xfrm_inner_extract_output(x, skb);
+	if (err)
+		return err;
+
+	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
+	skb->protocol = htons(ETH_P_IP);
+
+	switch (x->outer_mode.encap) {
+	case XFRM_MODE_BEET:
+		return xfrm4_beet_encap_add(x, skb);
+	case XFRM_MODE_TUNNEL:
+		return xfrm4_tunnel_encap_add(x, skb);
+	}
+
+	WARN_ON_ONCE(1);
+	return -EOPNOTSUPP;
+}
+
+static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	int err;
+
+	err = xfrm_inner_extract_output(x, skb);
+	if (err)
+		return err;
+
+	skb->ignore_df = 1;
+	skb->protocol = htons(ETH_P_IPV6);
+
+	switch (x->outer_mode.encap) {
+	case XFRM_MODE_BEET:
+		return xfrm6_beet_encap_add(x, skb);
+	case XFRM_MODE_TUNNEL:
+		return xfrm6_tunnel_encap_add(x, skb);
+	default:
+		WARN_ON_ONCE(1);
+		return -EOPNOTSUPP;
+	}
+#endif
+	WARN_ON_ONCE(1);
+	return -EAFNOSUPPORT;
+}
+
+static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	switch (x->outer_mode.encap) {
+	case XFRM_MODE_BEET:
+	case XFRM_MODE_TUNNEL:
+		if (x->outer_mode.family == AF_INET)
+			return xfrm4_prepare_output(x, skb);
+		if (x->outer_mode.family == AF_INET6)
+			return xfrm6_prepare_output(x, skb);
+		break;
+	case XFRM_MODE_TRANSPORT:
+		if (x->outer_mode.family == AF_INET)
+			return xfrm4_transport_output(x, skb);
+		if (x->outer_mode.family == AF_INET6)
+			return xfrm6_transport_output(x, skb);
+		break;
+	case XFRM_MODE_ROUTEOPTIMIZATION:
+		if (x->outer_mode.family == AF_INET6)
+			return xfrm6_ro_output(x, skb);
+		WARN_ON_ONCE(1);
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+#if IS_ENABLED(CONFIG_NET_PKTGEN)
+int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	return xfrm_outer_mode_output(x, skb);
+}
+EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
+#endif
+
+static int xfrm_output_one(struct sk_buff *skb, int err)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct xfrm_state *x = dst->xfrm;
+	struct net *net = xs_net(x);
+
+	if (err <= 0)
+		goto resume;
+
+	do {
+		err = xfrm_skb_check_space(skb);
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+			goto error_nolock;
+		}
+
+		skb->mark = xfrm_smark_get(skb->mark, x);
+
+		err = xfrm_outer_mode_output(x, skb);
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
+			goto error_nolock;
+		}
+
+		spin_lock_bh(&x->lock);
+
+		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
+			err = -EINVAL;
+			goto error;
+		}
+
+		err = xfrm_state_check_expire(x);
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
+			goto error;
+		}
+
+		err = xfrm_replay_overflow(x, skb);
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
+			goto error;
+		}
+
+		x->curlft.bytes += skb->len;
+		x->curlft.packets++;
+
+		spin_unlock_bh(&x->lock);
+
+		skb_dst_force(skb);
+		if (!skb_dst(skb)) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+			err = -EHOSTUNREACH;
+			goto error_nolock;
+		}
+
+		if (xfrm_offload(skb)) {
+			x->type_offload->encap(x, skb);
+		} else {
+			/* Inner headers are invalid now. */
+			skb->encapsulation = 0;
+
+			err = x->type->output(x, skb);
+			if (err == -EINPROGRESS)
+				goto out;
+		}
+
+resume:
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
+			goto error_nolock;
+		}
+
+		dst = skb_dst_pop(skb);
+		if (!dst) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+			err = -EHOSTUNREACH;
+			goto error_nolock;
+		}
+		skb_dst_set(skb, dst);
+		x = dst->xfrm;
+	} while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
+
+	return 0;
+
+error:
+	spin_unlock_bh(&x->lock);
+error_nolock:
+	kfree_skb(skb);
+out:
+	return err;
+}
+
+int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
+{
+	struct net *net = xs_net(skb_dst(skb)->xfrm);
+
+	while (likely((err = xfrm_output_one(skb, err)) == 0)) {
+		nf_reset_ct(skb);
+
+		err = skb_dst(skb)->ops->local_out(net, sk, skb);
+		if (unlikely(err != 1))
+			goto out;
+
+		if (!skb_dst(skb)->xfrm)
+			return dst_output(net, sk, skb);
+
+		err = nf_hook(skb_dst(skb)->ops->family,
+			      NF_INET_POST_ROUTING, net, sk, skb,
+			      NULL, skb_dst(skb)->dev, xfrm_output2);
+		if (unlikely(err != 1))
+			goto out;
+	}
+
+	if (err == -EINPROGRESS)
+		err = 0;
+
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(xfrm_output_resume);
+
+static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	return xfrm_output_resume(sk, skb, 1);
+}
+
+static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct sk_buff *segs, *nskb;
+
+	BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
+	BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
+	segs = skb_gso_segment(skb, 0);
+	kfree_skb(skb);
+	if (IS_ERR(segs))
+		return PTR_ERR(segs);
+	if (segs == NULL)
+		return -EINVAL;
+
+	skb_list_walk_safe(segs, segs, nskb) {
+		int err;
+
+		skb_mark_not_on_list(segs);
+		err = xfrm_output2(net, sk, segs);
+
+		if (unlikely(err)) {
+			kfree_skb_list(nskb);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+/* For partial checksum offload, the outer header checksum is calculated
+ * by software and the inner header checksum is calculated by hardware.
+ * This requires hardware to know the inner packet type to calculate
+ * the inner header checksum. Save inner ip protocol here to avoid
+ * traversing the packet in the vendor's xmit code.
+ * For IPsec tunnel mode save the ip protocol from the IP header of the
+ * plain text packet. Otherwise If the encap type is IPIP, just save
+ * skb->inner_ipproto in any other case get the ip protocol from the IP
+ * header.
+ */
+static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
+{
+	struct xfrm_offload *xo = xfrm_offload(skb);
+	const struct ethhdr *eth;
+
+	if (!xo)
+		return;
+
+	if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
+		switch (x->outer_mode.family) {
+		case AF_INET:
+			xo->inner_ipproto = ip_hdr(skb)->protocol;
+			break;
+		case AF_INET6:
+			xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
+			break;
+		default:
+			break;
+		}
+
+		return;
+	}
+
+	/* non-Tunnel Mode */
+	if (!skb->encapsulation)
+		return;
+
+	if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
+		xo->inner_ipproto = skb->inner_ipproto;
+		return;
+	}
+
+	if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
+		return;
+
+	eth = (struct ethhdr *)skb_inner_mac_header(skb);
+
+	switch (ntohs(eth->h_proto)) {
+	case ETH_P_IPV6:
+		xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
+		break;
+	case ETH_P_IP:
+		xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
+		break;
+	}
+}
+
+int xfrm_output(struct sock *sk, struct sk_buff *skb)
+{
+	struct net *net = dev_net(skb_dst(skb)->dev);
+	struct xfrm_state *x = skb_dst(skb)->xfrm;
+	int err;
+
+	switch (x->outer_mode.family) {
+	case AF_INET:
+		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+		IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
+		break;
+	case AF_INET6:
+		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
+
+		IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
+		break;
+	}
+
+	secpath_reset(skb);
+
+	if (xfrm_dev_offload_ok(skb, x)) {
+		struct sec_path *sp;
+
+		sp = secpath_set(skb);
+		if (!sp) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+			kfree_skb(skb);
+			return -ENOMEM;
+		}
+
+		sp->olen++;
+		sp->xvec[sp->len++] = x;
+		xfrm_state_hold(x);
+
+		xfrm_get_inner_ipproto(skb, x);
+		skb->encapsulation = 1;
+
+		if (skb_is_gso(skb)) {
+			if (skb->inner_protocol)
+				return xfrm_output_gso(net, sk, skb);
+
+			skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
+			goto out;
+		}
+
+		if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
+			goto out;
+	} else {
+		if (skb_is_gso(skb))
+			return xfrm_output_gso(net, sk, skb);
+	}
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		err = skb_checksum_help(skb);
+		if (err) {
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
+			kfree_skb(skb);
+			return err;
+		}
+	}
+
+out:
+	return xfrm_output2(net, sk, skb);
+}
+EXPORT_SYMBOL_GPL(xfrm_output);
+
+static int xfrm4_tunnel_check_size(struct sk_buff *skb)
+{
+	int mtu, ret = 0;
+
+	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
+		goto out;
+
+	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
+		goto out;
+
+	mtu = dst_mtu(skb_dst(skb));
+	if ((!skb_is_gso(skb) && skb->len > mtu) ||
+	    (skb_is_gso(skb) &&
+	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
+		skb->protocol = htons(ETH_P_IP);
+
+		if (skb->sk)
+			xfrm_local_error(skb, mtu);
+		else
+			icmp_send(skb, ICMP_DEST_UNREACH,
+				  ICMP_FRAG_NEEDED, htonl(mtu));
+		ret = -EMSGSIZE;
+	}
+out:
+	return ret;
+}
+
+static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int err;
+
+	if (x->outer_mode.encap == XFRM_MODE_BEET &&
+	    ip_is_fragment(ip_hdr(skb))) {
+		net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
+		return -EAFNOSUPPORT;
+	}
+
+	err = xfrm4_tunnel_check_size(skb);
+	if (err)
+		return err;
+
+	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
+
+	xfrm4_extract_header(skb);
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int xfrm6_tunnel_check_size(struct sk_buff *skb)
+{
+	int mtu, ret = 0;
+	struct dst_entry *dst = skb_dst(skb);
+
+	if (skb->ignore_df)
+		goto out;
+
+	mtu = dst_mtu(dst);
+	if (mtu < IPV6_MIN_MTU)
+		mtu = IPV6_MIN_MTU;
+
+	if ((!skb_is_gso(skb) && skb->len > mtu) ||
+	    (skb_is_gso(skb) &&
+	     !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
+		skb->dev = dst->dev;
+		skb->protocol = htons(ETH_P_IPV6);
+
+		if (xfrm6_local_dontfrag(skb->sk))
+			ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
+		else if (skb->sk)
+			xfrm_local_error(skb, mtu);
+		else
+			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+		ret = -EMSGSIZE;
+	}
+out:
+	return ret;
+}
+#endif
+
+static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	int err;
+
+	err = xfrm6_tunnel_check_size(skb);
+	if (err)
+		return err;
+
+	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
+
+	xfrm6_extract_header(skb);
+	return 0;
+#else
+	WARN_ON_ONCE(1);
+	return -EAFNOSUPPORT;
+#endif
+}
+
+static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	const struct xfrm_mode *inner_mode;
+
+	if (x->sel.family == AF_UNSPEC)
+		inner_mode = xfrm_ip2inner_mode(x,
+				xfrm_af2proto(skb_dst(skb)->ops->family));
+	else
+		inner_mode = &x->inner_mode;
+
+	if (inner_mode == NULL)
+		return -EAFNOSUPPORT;
+
+	switch (inner_mode->family) {
+	case AF_INET:
+		return xfrm4_extract_output(x, skb);
+	case AF_INET6:
+		return xfrm6_extract_output(x, skb);
+	}
+
+	return -EAFNOSUPPORT;
+}
+
+void xfrm_local_error(struct sk_buff *skb, int mtu)
+{
+	unsigned int proto;
+	struct xfrm_state_afinfo *afinfo;
+
+	if (skb->protocol == htons(ETH_P_IP))
+		proto = AF_INET;
+	else if (skb->protocol == htons(ETH_P_IPV6) &&
+		 skb->sk->sk_family == AF_INET6)
+		proto = AF_INET6;
+	else
+		return;
+
+	afinfo = xfrm_state_get_afinfo(proto);
+	if (afinfo) {
+		afinfo->local_error(skb, mtu);
+		rcu_read_unlock();
+	}
+}
+EXPORT_SYMBOL_GPL(xfrm_local_error);