Subject: [PATCH ipsec-next v2] esp: Consolidate esp4 and esp6

From: Steffen Klassert <[email-masked]>
Date: Wed, 6 May 2026 10:15:06 +0200

This patch merges common code of esp4.c and esp6.c into
xfrm_esp.c. This almost halves the size of the ESP
implementation for the price of three indirect calls
on UDP/TCP encapsulation. No functional changes.

Changes from the RFC version:

- Fix a typo in the commit message.

- Remove some old comments that don't make sense anymore.

- Let the ->input_encap functions return the needed offsets.

- Remove the IP_MAX_MTU check from UDP/TCP encap.
  The IPv4/IPv6 local_out function will do that ceck later.

- The comment on IPv4 ESP offload with UDP encapsulation
  is true for IPv4 and IPv6, so remove the IPv4 from the
  comment.

Changes since v1:

- Remove some now unused code.

- Whitespace fixes.

- Cleanup the header length calculation in the input path for
  UDP/TCP encapsulation.

- Move the skb_pull_rcsum() call to the generic esp_input_done2()
  function.

- Move the skb_postpull_rcsum() call to the offloading codepath,
  it is needed only there.

Signed-off-by: Steffen Klassert <[email-masked]>
Tested-by: Tobias Brunner <[email-masked]>
---
 include/net/esp.h       |    9 +-
 include/net/xfrm.h      |    3 +
 net/ipv4/esp4.c         | 1068 ++------------------------------------
 net/ipv4/esp4_offload.c |    3 +-
 net/ipv6/esp6.c         | 1086 ++-------------------------------------
 net/ipv6/esp6_offload.c |   12 +-
 net/xfrm/Makefile       |    1 +
 net/xfrm/xfrm_esp.c     | 1012 ++++++++++++++++++++++++++++++++++++
 8 files changed, 1135 insertions(+), 2059 deletions(-)
 create mode 100644 net/xfrm/xfrm_esp.c

diff --git a/include/net/esp.h b/include/net/esp.h
index 322950727dd0..e1ae485ac1c7 100644
--- a/include/net/esp.h
+++ b/include/net/esp.h
@@ -44,7 +44,10 @@ struct esp_info {
 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp);
 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp);
 int esp_input_done2(struct sk_buff *skb, int err);
-int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp);
-int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp);
-int esp6_input_done2(struct sk_buff *skb, int err);
+int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack);
+int esp_init_authenc(struct xfrm_state *x, struct netlink_ext_ack *extack);
+void esp_destroy(struct xfrm_state *x);
+int esp_input(struct xfrm_state *x, struct sk_buff *skb);
+int esp_output(struct xfrm_state *x, struct sk_buff *skb);
+
 #endif
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 10d3edde6b2f..d99b6f57ecda 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -455,7 +455,10 @@ struct xfrm_type {
 					      struct netlink_ext_ack *extack);
 	void			(*destructor)(struct xfrm_state *);
 	int			(*input)(struct xfrm_state *, struct sk_buff *skb);
+	int			(*input_encap)(struct sk_buff *skb, struct xfrm_state *x);
 	int			(*output)(struct xfrm_state *, struct sk_buff *pskb);
+	struct sock		*(*find_tcp_sk)(struct xfrm_state *x);
+	void			(*output_encap_csum)(struct sk_buff *skb);
 	int			(*reject)(struct xfrm_state *, struct sk_buff *,
 					  const struct flowi *);
 };
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 6dfc0bcdef65..0498bbb5060e 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -1,123 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0-only
-#define pr_fmt(fmt) "IPsec: " fmt
 
 #include <crypto/aead.h>
 #include <crypto/authenc.h>
-#include <linux/err.h>
-#include <linux/module.h>
 #include <net/ip.h>
-#include <net/xfrm.h>
 #include <net/esp.h>
-#include <linux/scatterlist.h>
-#include <linux/kernel.h>
-#include <linux/pfkeyv2.h>
-#include <linux/rtnetlink.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/in6.h>
 #include <net/icmp.h>
-#include <net/protocol.h>
-#include <net/udp.h>
-#include <net/tcp.h>
 #include <net/espintcp.h>
-#include <linux/skbuff_ref.h>
-
-#include <linux/highmem.h>
-
-struct esp_skb_cb {
-	struct xfrm_skb_cb xfrm;
-	void *tmp;
-};
-
-struct esp_output_extra {
-	__be32 seqhi;
-	u32 esphoff;
-};
-
-#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
-
-/*
- * Allocate an AEAD request structure with extra space for SG and IV.
- *
- * For alignment considerations the IV is placed at the front, followed
- * by the request and finally the SG list.
- *
- * TODO: Use spare space in skb for this where possible.
- */
-static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
-{
-	unsigned int len;
-
-	len = extralen;
-
-	len += crypto_aead_ivsize(aead);
-
-	if (len) {
-		len += crypto_aead_alignmask(aead) &
-		       ~(crypto_tfm_ctx_alignment() - 1);
-		len = ALIGN(len, crypto_tfm_ctx_alignment());
-	}
-
-	len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
-	len = ALIGN(len, __alignof__(struct scatterlist));
-
-	len += sizeof(struct scatterlist) * nfrags;
-
-	return kmalloc(len, GFP_ATOMIC);
-}
-
-static inline void *esp_tmp_extra(void *tmp)
-{
-	return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
-}
-
-static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
-{
-	return crypto_aead_ivsize(aead) ?
-	       PTR_ALIGN((u8 *)tmp + extralen,
-			 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
-}
-
-static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
-{
-	struct aead_request *req;
-
-	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
-				crypto_tfm_ctx_alignment());
-	aead_request_set_tfm(req, aead);
-	return req;
-}
-
-static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
-					     struct aead_request *req)
-{
-	return (void *)ALIGN((unsigned long)(req + 1) +
-			     crypto_aead_reqsize(aead),
-			     __alignof__(struct scatterlist));
-}
-
-static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
-{
-	struct crypto_aead *aead = x->data;
-	int extralen = 0;
-	u8 *iv;
-	struct aead_request *req;
-	struct scatterlist *sg;
-
-	if (x->props.flags & XFRM_STATE_ESN)
-		extralen += sizeof(struct esp_output_extra);
-
-	iv = esp_tmp_iv(aead, tmp, extralen);
-	req = esp_tmp_req(aead, iv);
-
-	/* Unref skb_frag_pages in the src scatterlist if necessary.
-	 * Skip the first sg which comes from skb->data.
-	 */
-	if (req->src != req->dst)
-		for (sg = sg_next(req->src); sg; sg = sg_next(sg))
-			skb_page_unref(page_to_netmem(sg_page(sg)),
-				       skb->pp_recycle);
-}
 
 #ifdef CONFIG_INET_ESPINTCP
 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
@@ -145,790 +33,69 @@ static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
 	return sk;
 }
 
-static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
-{
-	struct sock *sk;
-	int err;
-
-	rcu_read_lock();
-
-	sk = esp_find_tcp_sk(x);
-	err = PTR_ERR_OR_ZERO(sk);
-	if (err) {
-		kfree_skb(skb);
-		goto out;
-	}
-
-	bh_lock_sock(sk);
-	if (sock_owned_by_user(sk))
-		err = espintcp_queue_out(sk, skb);
-	else
-		err = espintcp_push_skb(sk, skb);
-	bh_unlock_sock(sk);
-
-	sock_put(sk);
-
-out:
-	rcu_read_unlock();
-	return err;
-}
-
-static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
-				   struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct xfrm_state *x = dst->xfrm;
-
-	return esp_output_tcp_finish(x, skb);
-}
-
-static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
-{
-	int err;
-
-	local_bh_disable();
-	err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
-	local_bh_enable();
-
-	/* EINPROGRESS just happens to do the right thing.  It
-	 * actually means that the skb has been consumed and
-	 * isn't coming back.
-	 */
-	return err ?: -EINPROGRESS;
-}
 #else
-static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
+static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
 {
 	WARN_ON(1);
-	return -EOPNOTSUPP;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 #endif
 
-static void esp_output_done(void *data, int err)
-{
-	struct sk_buff *skb = data;
-	struct xfrm_offload *xo = xfrm_offload(skb);
-	void *tmp;
-	struct xfrm_state *x;
-
-	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
-		struct sec_path *sp = skb_sec_path(skb);
-
-		x = sp->xvec[sp->len - 1];
-	} else {
-		x = skb_dst(skb)->xfrm;
-	}
-
-	tmp = ESP_SKB_CB(skb)->tmp;
-	esp_ssg_unref(x, tmp, skb);
-	kfree(tmp);
-
-	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
-		if (err) {
-			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
-			kfree_skb(skb);
-			return;
-		}
-
-		skb_push(skb, skb->data - skb_mac_header(skb));
-		secpath_reset(skb);
-		xfrm_dev_resume(skb);
-	} else {
-		if (!err &&
-		    x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) {
-			err = esp_output_tail_tcp(x, skb);
-			if (err != -EINPROGRESS)
-				kfree_skb(skb);
-		} else {
-			xfrm_output_resume(skb_to_full_sk(skb), skb, err);
-		}
-	}
-}
-
-/* Move ESP header back into place. */
-static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
-{
-	struct ip_esp_hdr *esph = (void *)(skb->data + offset);
-	void *tmp = ESP_SKB_CB(skb)->tmp;
-	__be32 *seqhi = esp_tmp_extra(tmp);
-
-	esph->seq_no = esph->spi;
-	esph->spi = *seqhi;
-}
-
-static void esp_output_restore_header(struct sk_buff *skb)
-{
-	void *tmp = ESP_SKB_CB(skb)->tmp;
-	struct esp_output_extra *extra = esp_tmp_extra(tmp);
-
-	esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
-				sizeof(__be32));
-}
-
-static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
-					       struct xfrm_state *x,
-					       struct ip_esp_hdr *esph,
-					       struct esp_output_extra *extra)
-{
-	/* For ESN we move the header forward by 4 bytes to
-	 * accommodate the high bits.  We will move it back after
-	 * encryption.
-	 */
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		__u32 seqhi;
-		struct xfrm_offload *xo = xfrm_offload(skb);
-
-		if (xo)
-			seqhi = xo->seq.hi;
-		else
-			seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
-
-		extra->esphoff = (unsigned char *)esph -
-				 skb_transport_header(skb);
-		esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
-		extra->seqhi = esph->spi;
-		esph->seq_no = htonl(seqhi);
-	}
-
-	esph->spi = x->id.spi;
-
-	return esph;
-}
-
-static void esp_output_done_esn(void *data, int err)
+static void esp4_output_encap_csum(struct sk_buff *skb)
 {
-	struct sk_buff *skb = data;
-
-	esp_output_restore_header(skb);
-	esp_output_done(data, err);
-}
-
-static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
-					       int encap_type,
-					       struct esp_info *esp,
-					       __be16 sport,
-					       __be16 dport)
-{
-	struct udphdr *uh;
-	unsigned int len;
-	struct xfrm_offload *xo = xfrm_offload(skb);
-
-	len = skb->len + esp->tailen - skb_transport_offset(skb);
-	if (len + sizeof(struct iphdr) > IP_MAX_MTU)
-		return ERR_PTR(-EMSGSIZE);
-
-	uh = (struct udphdr *)esp->esph;
-	uh->source = sport;
-	uh->dest = dport;
-	uh->len = htons(len);
-	uh->check = 0;
-
-	/* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
-	 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
-	 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
-	 */
-	if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
-		*skb_mac_header(skb) = IPPROTO_UDP;
-
-	return (struct ip_esp_hdr *)(uh + 1);
-}
-
-#ifdef CONFIG_INET_ESPINTCP
-static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
-						    struct sk_buff *skb,
-						    struct esp_info *esp)
-{
-	__be16 *lenp = (void *)esp->esph;
-	struct ip_esp_hdr *esph;
-	unsigned int len;
-	struct sock *sk;
-
-	len = skb->len + esp->tailen - skb_transport_offset(skb);
-	if (len > IP_MAX_MTU)
-		return ERR_PTR(-EMSGSIZE);
-
-	rcu_read_lock();
-	sk = esp_find_tcp_sk(x);
-	rcu_read_unlock();
-
-	if (IS_ERR(sk))
-		return ERR_CAST(sk);
-
-	sock_put(sk);
-
-	*lenp = htons(len);
-	esph = (struct ip_esp_hdr *)(lenp + 1);
-
-	return esph;
-}
-#else
-static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
-						    struct sk_buff *skb,
-						    struct esp_info *esp)
-{
-	return ERR_PTR(-EOPNOTSUPP);
 }
-#endif
 
-static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
-			    struct esp_info *esp)
+static int esp4_input_encap(struct sk_buff *skb, struct xfrm_state *x)
 {
+	const struct iphdr *iph = ip_hdr(skb);
+	int ihl = iph->ihl * 4;
 	struct xfrm_encap_tmpl *encap = x->encap;
-	struct ip_esp_hdr *esph;
-	__be16 sport, dport;
-	int encap_type;
-
-	spin_lock_bh(&x->lock);
-	sport = encap->encap_sport;
-	dport = encap->encap_dport;
-	encap_type = encap->encap_type;
-	spin_unlock_bh(&x->lock);
+	struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
+	struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
+	int ret = skb_network_header_len(skb);
+	__be16 source;
 
-	switch (encap_type) {
-	default:
-	case UDP_ENCAP_ESPINUDP:
-		esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
-		break;
+	switch (x->encap->encap_type) {
 	case TCP_ENCAP_ESPINTCP:
-		esph = esp_output_tcp_encap(x, skb, esp);
+		source = th->source;
+		ret -= sizeof(struct tcphdr);
 		break;
-	}
-
-	if (IS_ERR(esph))
-		return PTR_ERR(esph);
-
-	esp->esph = esph;
-
-	return 0;
-}
-
-int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
-{
-	u8 *tail;
-	int nfrags;
-	int esph_offset;
-	struct page *page;
-	struct sk_buff *trailer;
-	int tailen = esp->tailen;
-
-	/* this is non-NULL only with TCP/UDP Encapsulation */
-	if (x->encap) {
-		int err = esp_output_encap(x, skb, esp);
-
-		if (err < 0)
-			return err;
-	}
-
-	if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
-	    ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
-		goto cow;
-
-	if (!skb_cloned(skb)) {
-		if (tailen <= skb_tailroom(skb)) {
-			nfrags = 1;
-			trailer = skb;
-			tail = skb_tail_pointer(trailer);
-
-			goto skip_cow;
-		} else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
-			   && !skb_has_frag_list(skb)) {
-			int allocsize;
-			struct sock *sk = skb->sk;
-			struct page_frag *pfrag = &x->xfrag;
-
-			esp->inplace = false;
-
-			allocsize = ALIGN(tailen, L1_CACHE_BYTES);
-
-			spin_lock_bh(&x->lock);
-
-			if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
-				spin_unlock_bh(&x->lock);
-				goto cow;
-			}
-
-			page = pfrag->page;
-			get_page(page);
-
-			tail = page_address(page) + pfrag->offset;
-
-			esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
-
-			nfrags = skb_shinfo(skb)->nr_frags;
-
-			__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
-					     tailen);
-			skb_shinfo(skb)->nr_frags = ++nfrags;
-
-			pfrag->offset = pfrag->offset + allocsize;
-
-			spin_unlock_bh(&x->lock);
-
-			nfrags++;
-
-			skb_len_add(skb, tailen);
-			if (sk && sk_fullsock(sk))
-				refcount_add(tailen, &sk->sk_wmem_alloc);
-
-			goto out;
-		}
-	}
-
-cow:
-	esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
-
-	nfrags = skb_cow_data(skb, tailen, &trailer);
-	if (nfrags < 0)
-		goto out;
-	tail = skb_tail_pointer(trailer);
-	esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
-
-skip_cow:
-	esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
-	pskb_put(skb, trailer, tailen);
-
-out:
-	return nfrags;
-}
-EXPORT_SYMBOL_GPL(esp_output_head);
-
-int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
-{
-	u8 *iv;
-	int alen;
-	void *tmp;
-	int ivlen;
-	int assoclen;
-	int extralen;
-	struct page *page;
-	struct ip_esp_hdr *esph;
-	struct crypto_aead *aead;
-	struct aead_request *req;
-	struct scatterlist *sg, *dsg;
-	struct esp_output_extra *extra;
-	int err = -ENOMEM;
-
-	assoclen = sizeof(struct ip_esp_hdr);
-	extralen = 0;
-
-	if (x->props.flags & XFRM_STATE_ESN) {
-		extralen += sizeof(*extra);
-		assoclen += sizeof(__be32);
-	}
-
-	aead = x->data;
-	alen = crypto_aead_authsize(aead);
-	ivlen = crypto_aead_ivsize(aead);
-
-	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
-	if (!tmp)
-		goto error;
-
-	extra = esp_tmp_extra(tmp);
-	iv = esp_tmp_iv(aead, tmp, extralen);
-	req = esp_tmp_req(aead, iv);
-	sg = esp_req_sg(aead, req);
-
-	if (esp->inplace)
-		dsg = sg;
-	else
-		dsg = &sg[esp->nfrags];
-
-	esph = esp_output_set_extra(skb, x, esp->esph, extra);
-	esp->esph = esph;
-
-	sg_init_table(sg, esp->nfrags);
-	err = skb_to_sgvec(skb, sg,
-		           (unsigned char *)esph - skb->data,
-		           assoclen + ivlen + esp->clen + alen);
-	if (unlikely(err < 0))
-		goto error_free;
-
-	if (!esp->inplace) {
-		int allocsize;
-		struct page_frag *pfrag = &x->xfrag;
-
-		allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
-
-		spin_lock_bh(&x->lock);
-		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
-			spin_unlock_bh(&x->lock);
-			goto error_free;
-		}
-
-		skb_shinfo(skb)->nr_frags = 1;
-
-		page = pfrag->page;
-		get_page(page);
-		/* replace page frags in skb with new page */
-		__skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
-		pfrag->offset = pfrag->offset + allocsize;
-		spin_unlock_bh(&x->lock);
-
-		sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
-		err = skb_to_sgvec(skb, dsg,
-			           (unsigned char *)esph - skb->data,
-			           assoclen + ivlen + esp->clen + alen);
-		if (unlikely(err < 0))
-			goto error_free;
-	}
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		aead_request_set_callback(req, 0, esp_output_done_esn, skb);
-	else
-		aead_request_set_callback(req, 0, esp_output_done, skb);
-
-	aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
-	aead_request_set_ad(req, assoclen);
-
-	memset(iv, 0, ivlen);
-	memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
-	       min(ivlen, 8));
-
-	ESP_SKB_CB(skb)->tmp = tmp;
-	err = crypto_aead_encrypt(req);
-
-	switch (err) {
-	case -EINPROGRESS:
-		goto error;
-
-	case -ENOSPC:
-		err = NET_XMIT_DROP;
+	case UDP_ENCAP_ESPINUDP:
+		source = uh->source;
+		ret -= sizeof(struct udphdr);
 		break;
-
-	case 0:
-		if ((x->props.flags & XFRM_STATE_ESN))
-			esp_output_restore_header(skb);
-	}
-
-	if (sg != dsg)
-		esp_ssg_unref(x, tmp, skb);
-
-	if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
-		err = esp_output_tail_tcp(x, skb);
-
-error_free:
-	kfree(tmp);
-error:
-	return err;
-}
-EXPORT_SYMBOL_GPL(esp_output_tail);
-
-static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
-{
-	int alen;
-	int blksize;
-	struct ip_esp_hdr *esph;
-	struct crypto_aead *aead;
-	struct esp_info esp;
-
-	esp.inplace = true;
-
-	esp.proto = *skb_mac_header(skb);
-	*skb_mac_header(skb) = IPPROTO_ESP;
-
-	/* skb is pure payload to encrypt */
-
-	aead = x->data;
-	alen = crypto_aead_authsize(aead);
-
-	esp.tfclen = 0;
-	if (x->tfcpad) {
-		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
-		u32 padto;
-
-		padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
-		if (skb->len < padto)
-			esp.tfclen = padto - skb->len;
-	}
-	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
-	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
-	esp.plen = esp.clen - skb->len - esp.tfclen;
-	esp.tailen = esp.tfclen + esp.plen + alen;
-
-	esp.esph = ip_esp_hdr(skb);
-
-	esp.nfrags = esp_output_head(x, skb, &esp);
-	if (esp.nfrags < 0)
-		return esp.nfrags;
-
-	esph = esp.esph;
-	esph->spi = x->id.spi;
-
-	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
-	esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
-				 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
-
-	skb_push(skb, -skb_network_offset(skb));
-
-	return esp_output_tail(x, skb, &esp);
-}
-
-static inline int esp_remove_trailer(struct sk_buff *skb)
-{
-	struct xfrm_state *x = xfrm_input_state(skb);
-	struct crypto_aead *aead = x->data;
-	int alen, hlen, elen;
-	int padlen, trimlen;
-	__wsum csumdiff;
-	u8 nexthdr[2];
-	int ret;
-
-	alen = crypto_aead_authsize(aead);
-	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
-	elen = skb->len - hlen;
-
-	if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
-		BUG();
-
-	ret = -EINVAL;
-	padlen = nexthdr[0];
-	if (padlen + 2 + alen >= elen) {
-		net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
-				    padlen + 2, elen - alen);
-		goto out;
-	}
-
-	trimlen = alen + padlen + 2;
-	if (skb->ip_summed == CHECKSUM_COMPLETE) {
-		csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
-		skb->csum = csum_block_sub(skb->csum, csumdiff,
-					   skb->len - trimlen);
-	}
-	ret = pskb_trim(skb, skb->len - trimlen);
-	if (unlikely(ret))
-		return ret;
-
-	ret = nexthdr[1];
-
-out:
-	return ret;
-}
-
-int esp_input_done2(struct sk_buff *skb, int err)
-{
-	const struct iphdr *iph;
-	struct xfrm_state *x = xfrm_input_state(skb);
-	struct xfrm_offload *xo = xfrm_offload(skb);
-	struct crypto_aead *aead = x->data;
-	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
-	int ihl;
-
-	if (!xo || !(xo->flags & CRYPTO_DONE))
-		kfree(ESP_SKB_CB(skb)->tmp);
-
-	if (unlikely(err))
-		goto out;
-
-	err = esp_remove_trailer(skb);
-	if (unlikely(err < 0))
+	default:
+		WARN_ON_ONCE(1);
+		ret = -1;
 		goto out;
-
-	iph = ip_hdr(skb);
-	ihl = iph->ihl * 4;
-
-	if (x->encap) {
-		struct xfrm_encap_tmpl *encap = x->encap;
-		struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
-		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
-		__be16 source;
-
-		switch (x->encap->encap_type) {
-		case TCP_ENCAP_ESPINTCP:
-			source = th->source;
-			break;
-		case UDP_ENCAP_ESPINUDP:
-			source = uh->source;
-			break;
-		default:
-			WARN_ON_ONCE(1);
-			err = -EINVAL;
-			goto out;
-		}
-
-		/*
-		 * 1) if the NAT-T peer's IP or port changed then
-		 *    advertise the change to the keying daemon.
-		 *    This is an inbound SA, so just compare
-		 *    SRC ports.
-		 */
-		if (iph->saddr != x->props.saddr.a4 ||
-		    source != encap->encap_sport) {
-			xfrm_address_t ipaddr;
-
-			ipaddr.a4 = iph->saddr;
-			km_new_mapping(x, &ipaddr, source);
-
-			/* XXX: perhaps add an extra
-			 * policy check here, to see
-			 * if we should allow or
-			 * reject a packet from a
-			 * different source
-			 * address/port.
-			 */
-		}
-
-		/*
-		 * 2) ignore UDP/TCP checksums in case
-		 *    of NAT-T in Transport Mode, or
-		 *    perform other post-processing fixes
-		 *    as per draft-ietf-ipsec-udp-encaps-06,
-		 *    section 3.1.2
-		 */
-		if (x->props.mode == XFRM_MODE_TRANSPORT)
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
 	}
 
-	skb_pull_rcsum(skb, hlen);
-	if (x->props.mode == XFRM_MODE_TUNNEL ||
-	    x->props.mode == XFRM_MODE_IPTFS)
-		skb_reset_transport_header(skb);
-	else
-		skb_set_transport_header(skb, -ihl);
-
-	/* RFC4303: Drop dummy packets without any error */
-	if (err == IPPROTO_NONE)
-		err = -EINVAL;
-
-out:
-	return err;
-}
-EXPORT_SYMBOL_GPL(esp_input_done2);
-
-static void esp_input_done(void *data, int err)
-{
-	struct sk_buff *skb = data;
-
-	xfrm_input_resume(skb, esp_input_done2(skb, err));
-}
-
-static void esp_input_restore_header(struct sk_buff *skb)
-{
-	esp_restore_header(skb, 0);
-	__skb_pull(skb, 4);
-}
-
-static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
-{
-	struct xfrm_state *x = xfrm_input_state(skb);
-	struct ip_esp_hdr *esph;
-
-	/* For ESN we move the header forward by 4 bytes to
-	 * accommodate the high bits.  We will move it back after
-	 * decryption.
+	/*
+	 * 1) if the NAT-T peer's IP or port changed then
+	 *    advertise the change to the keying daemon.
+	 *    This is an inbound SA, so just compare
+	 *    SRC ports.
 	 */
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		esph = skb_push(skb, 4);
-		*seqhi = esph->spi;
-		esph->spi = esph->seq_no;
-		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
-	}
-}
-
-static void esp_input_done_esn(void *data, int err)
-{
-	struct sk_buff *skb = data;
+	if (iph->saddr != x->props.saddr.a4 ||
+	    source != encap->encap_sport) {
+		xfrm_address_t ipaddr;
 
-	esp_input_restore_header(skb);
-	esp_input_done(data, err);
-}
-
-/*
- * Note: detecting truncated vs. non-truncated authentication data is very
- * expensive, so we only support truncated data, which is the recommended
- * and common case.
- */
-static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
-{
-	struct crypto_aead *aead = x->data;
-	struct aead_request *req;
-	struct sk_buff *trailer;
-	int ivlen = crypto_aead_ivsize(aead);
-	int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
-	int nfrags;
-	int assoclen;
-	int seqhilen;
-	__be32 *seqhi;
-	void *tmp;
-	u8 *iv;
-	struct scatterlist *sg;
-	int err = -EINVAL;
-
-	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
-		goto out;
-
-	if (elen <= 0)
-		goto out;
-
-	assoclen = sizeof(struct ip_esp_hdr);
-	seqhilen = 0;
-
-	if (x->props.flags & XFRM_STATE_ESN) {
-		seqhilen += sizeof(__be32);
-		assoclen += seqhilen;
-	}
-
-	if (!skb_cloned(skb)) {
-		if (!skb_is_nonlinear(skb)) {
-			nfrags = 1;
-
-			goto skip_cow;
-		} else if (!skb_has_frag_list(skb)) {
-			nfrags = skb_shinfo(skb)->nr_frags;
-			nfrags++;
-
-			goto skip_cow;
-		}
-	}
-
-	err = skb_cow_data(skb, 0, &trailer);
-	if (err < 0)
-		goto out;
-
-	nfrags = err;
-
-skip_cow:
-	err = -ENOMEM;
-	tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
-	if (!tmp)
-		goto out;
-
-	ESP_SKB_CB(skb)->tmp = tmp;
-	seqhi = esp_tmp_extra(tmp);
-	iv = esp_tmp_iv(aead, tmp, seqhilen);
-	req = esp_tmp_req(aead, iv);
-	sg = esp_req_sg(aead, req);
-
-	esp_input_set_header(skb, seqhi);
-
-	sg_init_table(sg, nfrags);
-	err = skb_to_sgvec(skb, sg, 0, skb->len);
-	if (unlikely(err < 0)) {
-		kfree(tmp);
-		goto out;
+		ipaddr.a4 = iph->saddr;
+		km_new_mapping(x, &ipaddr, source);
 	}
 
-	skb->ip_summed = CHECKSUM_NONE;
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		aead_request_set_callback(req, 0, esp_input_done_esn, skb);
-	else
-		aead_request_set_callback(req, 0, esp_input_done, skb);
-
-	aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
-	aead_request_set_ad(req, assoclen);
-
-	err = crypto_aead_decrypt(req);
-	if (err == -EINPROGRESS)
-		goto out;
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		esp_input_restore_header(skb);
-
-	err = esp_input_done2(skb, err);
+	/*
+	 * 2) ignore UDP/TCP checksums in case
+	 *    of NAT-T in Transport Mode, or
+	 *    perform other post-processing fixes
+	 *    as per draft-ietf-ipsec-udp-encaps-06,
+	 *    section 3.1.2
+	 */
+	if (x->props.mode == XFRM_MODE_TRANSPORT)
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 out:
-	return err;
+	return ret;
 }
 
 static int esp4_err(struct sk_buff *skb, u32 info)
@@ -963,146 +130,6 @@ static int esp4_err(struct sk_buff *skb, u32 info)
 	return 0;
 }
 
-static void esp_destroy(struct xfrm_state *x)
-{
-	struct crypto_aead *aead = x->data;
-
-	if (!aead)
-		return;
-
-	crypto_free_aead(aead);
-}
-
-static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
-{
-	char aead_name[CRYPTO_MAX_ALG_NAME];
-	struct crypto_aead *aead;
-	int err;
-
-	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
-		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
-		NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-		return -ENAMETOOLONG;
-	}
-
-	aead = crypto_alloc_aead(aead_name, 0, 0);
-	err = PTR_ERR(aead);
-	if (IS_ERR(aead))
-		goto error;
-
-	x->data = aead;
-
-	err = crypto_aead_setkey(aead, x->aead->alg_key,
-				 (x->aead->alg_key_len + 7) / 8);
-	if (err)
-		goto error;
-
-	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
-	if (err)
-		goto error;
-
-	return 0;
-
-error:
-	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-	return err;
-}
-
-static int esp_init_authenc(struct xfrm_state *x,
-			    struct netlink_ext_ack *extack)
-{
-	struct crypto_aead *aead;
-	struct crypto_authenc_key_param *param;
-	struct rtattr *rta;
-	char *key;
-	char *p;
-	char authenc_name[CRYPTO_MAX_ALG_NAME];
-	unsigned int keylen;
-	int err;
-
-	err = -ENAMETOOLONG;
-
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
-			     "%s%sauthencesn(%s,%s)%s",
-			     x->geniv ?: "", x->geniv ? "(" : "",
-			     x->aalg ? x->aalg->alg_name : "digest_null",
-			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
-			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-			goto error;
-		}
-	} else {
-		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
-			     "%s%sauthenc(%s,%s)%s",
-			     x->geniv ?: "", x->geniv ? "(" : "",
-			     x->aalg ? x->aalg->alg_name : "digest_null",
-			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
-			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-			goto error;
-		}
-	}
-
-	aead = crypto_alloc_aead(authenc_name, 0, 0);
-	err = PTR_ERR(aead);
-	if (IS_ERR(aead)) {
-		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-		goto error;
-	}
-
-	x->data = aead;
-
-	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
-		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
-	err = -ENOMEM;
-	key = kmalloc(keylen, GFP_KERNEL);
-	if (!key)
-		goto error;
-
-	p = key;
-	rta = (void *)p;
-	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
-	rta->rta_len = RTA_LENGTH(sizeof(*param));
-	param = RTA_DATA(rta);
-	p += RTA_SPACE(sizeof(*param));
-
-	if (x->aalg) {
-		struct xfrm_algo_desc *aalg_desc;
-
-		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
-		p += (x->aalg->alg_key_len + 7) / 8;
-
-		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
-		BUG_ON(!aalg_desc);
-
-		err = -EINVAL;
-		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
-		    crypto_aead_authsize(aead)) {
-			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-			goto free_key;
-		}
-
-		err = crypto_aead_setauthsize(
-			aead, x->aalg->alg_trunc_len / 8);
-		if (err) {
-			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-			goto free_key;
-		}
-	}
-
-	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
-	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
-
-	err = crypto_aead_setkey(aead, key, keylen);
-
-free_key:
-	kfree_sensitive(key);
-
-error:
-	return err;
-}
-
 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
@@ -1167,13 +194,16 @@ static int esp4_rcv_cb(struct sk_buff *skb, int err)
 
 static const struct xfrm_type esp_type =
 {
-	.owner		= THIS_MODULE,
-	.proto	     	= IPPROTO_ESP,
-	.flags		= XFRM_TYPE_REPLAY_PROT,
-	.init_state	= esp_init_state,
-	.destructor	= esp_destroy,
-	.input		= esp_input,
-	.output		= esp_output,
+	.owner			= THIS_MODULE,
+	.proto			= IPPROTO_ESP,
+	.flags			= XFRM_TYPE_REPLAY_PROT,
+	.init_state		= esp_init_state,
+	.destructor		= esp_destroy,
+	.input			= esp_input,
+	.input_encap		= esp4_input_encap,
+	.output			= esp_output,
+	.find_tcp_sk		= esp_find_tcp_sk,
+	.output_encap_csum	= esp4_output_encap_csum,
 };
 
 static struct xfrm4_protocol esp4_protocol = {
diff --git a/net/ipv4/esp4_offload.c b/net/ipv4/esp4_offload.c
index abd77162f5e7..293623dacdd4 100644
--- a/net/ipv4/esp4_offload.c
+++ b/net/ipv4/esp4_offload.c
@@ -252,8 +252,9 @@ static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct crypto_aead *aead = x->data;
 	struct xfrm_offload *xo = xfrm_offload(skb);
+	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 
-	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
+	if (!pskb_may_pull(skb, hlen))
 		return -EINVAL;
 
 	if (!(xo->flags & CRYPTO_DONE))
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 9f75313734f8..9d6e03051086 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -11,130 +11,15 @@
  *	This file is derived from net/ipv4/esp.c
  */
 
-#define pr_fmt(fmt) "IPv6: " fmt
-
 #include <crypto/aead.h>
 #include <crypto/authenc.h>
-#include <linux/err.h>
-#include <linux/module.h>
 #include <net/ip.h>
-#include <net/xfrm.h>
 #include <net/esp.h>
-#include <linux/scatterlist.h>
-#include <linux/kernel.h>
-#include <linux/pfkeyv2.h>
-#include <linux/random.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
 #include <net/ip6_checksum.h>
 #include <net/ip6_route.h>
-#include <net/icmp.h>
-#include <net/ipv6.h>
-#include <net/protocol.h>
-#include <net/udp.h>
 #include <linux/icmpv6.h>
-#include <net/tcp.h>
 #include <net/espintcp.h>
 #include <net/inet6_hashtables.h>
-#include <linux/skbuff_ref.h>
-
-#include <linux/highmem.h>
-
-struct esp_skb_cb {
-	struct xfrm_skb_cb xfrm;
-	void *tmp;
-};
-
-struct esp_output_extra {
-	__be32 seqhi;
-	u32 esphoff;
-};
-
-#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
-
-/*
- * Allocate an AEAD request structure with extra space for SG and IV.
- *
- * For alignment considerations the upper 32 bits of the sequence number are
- * placed at the front, if present. Followed by the IV, the request and finally
- * the SG list.
- *
- * TODO: Use spare space in skb for this where possible.
- */
-static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
-{
-	unsigned int len;
-
-	len = seqihlen;
-
-	len += crypto_aead_ivsize(aead);
-
-	if (len) {
-		len += crypto_aead_alignmask(aead) &
-		       ~(crypto_tfm_ctx_alignment() - 1);
-		len = ALIGN(len, crypto_tfm_ctx_alignment());
-	}
-
-	len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
-	len = ALIGN(len, __alignof__(struct scatterlist));
-
-	len += sizeof(struct scatterlist) * nfrags;
-
-	return kmalloc(len, GFP_ATOMIC);
-}
-
-static inline void *esp_tmp_extra(void *tmp)
-{
-	return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
-}
-
-static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
-{
-	return crypto_aead_ivsize(aead) ?
-	       PTR_ALIGN((u8 *)tmp + seqhilen,
-			 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
-}
-
-static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
-{
-	struct aead_request *req;
-
-	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
-				crypto_tfm_ctx_alignment());
-	aead_request_set_tfm(req, aead);
-	return req;
-}
-
-static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
-					     struct aead_request *req)
-{
-	return (void *)ALIGN((unsigned long)(req + 1) +
-			     crypto_aead_reqsize(aead),
-			     __alignof__(struct scatterlist));
-}
-
-static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
-{
-	struct crypto_aead *aead = x->data;
-	int extralen = 0;
-	u8 *iv;
-	struct aead_request *req;
-	struct scatterlist *sg;
-
-	if (x->props.flags & XFRM_STATE_ESN)
-		extralen += sizeof(struct esp_output_extra);
-
-	iv = esp_tmp_iv(aead, tmp, extralen);
-	req = esp_tmp_req(aead, iv);
-
-	/* Unref skb_frag_pages in the src scatterlist if necessary.
-	 * Skip the first sg which comes from skb->data.
-	 */
-	if (req->src != req->dst)
-		for (sg = sg_next(req->src); sg; sg = sg_next(sg))
-			skb_page_unref(page_to_netmem(sg_page(sg)),
-				       skb->pp_recycle);
-}
 
 #ifdef CONFIG_INET6_ESPINTCP
 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
@@ -162,66 +47,15 @@ static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
 	return sk;
 }
 
-static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
-{
-	struct sock *sk;
-	int err;
-
-	rcu_read_lock();
-
-	sk = esp6_find_tcp_sk(x);
-	err = PTR_ERR_OR_ZERO(sk);
-	if (err) {
-		kfree_skb(skb);
-		goto out;
-	}
-
-	bh_lock_sock(sk);
-	if (sock_owned_by_user(sk))
-		err = espintcp_queue_out(sk, skb);
-	else
-		err = espintcp_push_skb(sk, skb);
-	bh_unlock_sock(sk);
-
-	sock_put(sk);
-
-out:
-	rcu_read_unlock();
-	return err;
-}
-
-static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
-				   struct sk_buff *skb)
-{
-	struct dst_entry *dst = skb_dst(skb);
-	struct xfrm_state *x = dst->xfrm;
-
-	return esp_output_tcp_finish(x, skb);
-}
-
-static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
-{
-	int err;
-
-	local_bh_disable();
-	err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
-	local_bh_enable();
-
-	/* EINPROGRESS just happens to do the right thing.  It
-	 * actually means that the skb has been consumed and
-	 * isn't coming back.
-	 */
-	return err ?: -EINPROGRESS;
-}
 #else
-static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
+static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
 {
 	WARN_ON(1);
-	return -EOPNOTSUPP;
+	return ERR_PTR(-EOPNOTSUPP);
 }
 #endif
 
-static void esp_output_encap_csum(struct sk_buff *skb)
+static void esp6_output_encap_csum(struct sk_buff *skb)
 {
 	/* UDP encap with IPv6 requires a valid checksum */
 	if (*skb_mac_header(skb) == IPPROTO_UDP) {
@@ -238,738 +72,63 @@ static void esp_output_encap_csum(struct sk_buff *skb)
 	}
 }
 
-static void esp_output_done(void *data, int err)
-{
-	struct sk_buff *skb = data;
-	struct xfrm_offload *xo = xfrm_offload(skb);
-	void *tmp;
-	struct xfrm_state *x;
-
-	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
-		struct sec_path *sp = skb_sec_path(skb);
-
-		x = sp->xvec[sp->len - 1];
-	} else {
-		x = skb_dst(skb)->xfrm;
-	}
-
-	tmp = ESP_SKB_CB(skb)->tmp;
-	esp_ssg_unref(x, tmp, skb);
-	kfree(tmp);
-
-	esp_output_encap_csum(skb);
-
-	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
-		if (err) {
-			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
-			kfree_skb(skb);
-			return;
-		}
-
-		skb_push(skb, skb->data - skb_mac_header(skb));
-		secpath_reset(skb);
-		xfrm_dev_resume(skb);
-	} else {
-		if (!err &&
-		    x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) {
-			err = esp_output_tail_tcp(x, skb);
-			if (err != -EINPROGRESS)
-				kfree_skb(skb);
-		} else {
-			xfrm_output_resume(skb_to_full_sk(skb), skb, err);
-		}
-	}
-}
-
-/* Move ESP header back into place. */
-static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
-{
-	struct ip_esp_hdr *esph = (void *)(skb->data + offset);
-	void *tmp = ESP_SKB_CB(skb)->tmp;
-	__be32 *seqhi = esp_tmp_extra(tmp);
-
-	esph->seq_no = esph->spi;
-	esph->spi = *seqhi;
-}
-
-static void esp_output_restore_header(struct sk_buff *skb)
-{
-	void *tmp = ESP_SKB_CB(skb)->tmp;
-	struct esp_output_extra *extra = esp_tmp_extra(tmp);
-
-	esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
-				sizeof(__be32));
-}
-
-static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
-					     struct xfrm_state *x,
-					     struct ip_esp_hdr *esph,
-					     struct esp_output_extra *extra)
-{
-	/* For ESN we move the header forward by 4 bytes to
-	 * accommodate the high bits.  We will move it back after
-	 * encryption.
-	 */
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		__u32 seqhi;
-		struct xfrm_offload *xo = xfrm_offload(skb);
-
-		if (xo)
-			seqhi = xo->seq.hi;
-		else
-			seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
-
-		extra->esphoff = (unsigned char *)esph -
-				 skb_transport_header(skb);
-		esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
-		extra->seqhi = esph->spi;
-		esph->seq_no = htonl(seqhi);
-	}
-
-	esph->spi = x->id.spi;
-
-	return esph;
-}
-
-static void esp_output_done_esn(void *data, int err)
-{
-	struct sk_buff *skb = data;
-
-	esp_output_restore_header(skb);
-	esp_output_done(data, err);
-}
-
-static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
-					       int encap_type,
-					       struct esp_info *esp,
-					       __be16 sport,
-					       __be16 dport)
+static int esp6_input_encap(struct sk_buff *skb, struct xfrm_state *x)
 {
+	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	int offset = skb_network_offset(skb) + sizeof(*ip6h);
+	struct xfrm_encap_tmpl *encap = x->encap;
+	int hdr_len = skb_network_header_len(skb);
+	u8 nexthdr = ip6h->nexthdr;
+	__be16 frag_off, source;
 	struct udphdr *uh;
-	unsigned int len;
-
-	len = skb->len + esp->tailen - skb_transport_offset(skb);
-	if (len > U16_MAX)
-		return ERR_PTR(-EMSGSIZE);
-
-	uh = (struct udphdr *)esp->esph;
-	uh->source = sport;
-	uh->dest = dport;
-	uh->len = htons(len);
-	uh->check = 0;
-
-	*skb_mac_header(skb) = IPPROTO_UDP;
-
-	return (struct ip_esp_hdr *)(uh + 1);
-}
-
-#ifdef CONFIG_INET6_ESPINTCP
-static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
-						struct sk_buff *skb,
-						struct esp_info *esp)
-{
-	__be16 *lenp = (void *)esp->esph;
-	struct ip_esp_hdr *esph;
-	unsigned int len;
-	struct sock *sk;
-
-	len = skb->len + esp->tailen - skb_transport_offset(skb);
-	if (len > IP_MAX_MTU)
-		return ERR_PTR(-EMSGSIZE);
-
-	rcu_read_lock();
-	sk = esp6_find_tcp_sk(x);
-	rcu_read_unlock();
-
-	if (IS_ERR(sk))
-		return ERR_CAST(sk);
-
-	sock_put(sk);
-
-	*lenp = htons(len);
-	esph = (struct ip_esp_hdr *)(lenp + 1);
+	struct tcphdr *th;
+	int ret;
 
-	return esph;
-}
-#else
-static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
-						struct sk_buff *skb,
-						struct esp_info *esp)
-{
-	return ERR_PTR(-EOPNOTSUPP);
-}
-#endif
+	ret = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
+	if (ret == -1)
+		return ret;
 
-static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
-			    struct esp_info *esp)
-{
-	struct xfrm_encap_tmpl *encap = x->encap;
-	struct ip_esp_hdr *esph;
-	__be16 sport, dport;
-	int encap_type;
+	ret += hdr_len;
 
-	spin_lock_bh(&x->lock);
-	sport = encap->encap_sport;
-	dport = encap->encap_dport;
-	encap_type = encap->encap_type;
-	spin_unlock_bh(&x->lock);
+	uh = (void *)(skb->data + ret);
+	th = (void *)(skb->data + ret);
 
-	switch (encap_type) {
-	default:
-	case UDP_ENCAP_ESPINUDP:
-		esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
-		break;
+	switch (x->encap->encap_type) {
 	case TCP_ENCAP_ESPINTCP:
-		esph = esp6_output_tcp_encap(x, skb, esp);
+		source = th->source;
 		break;
-	}
-
-	if (IS_ERR(esph))
-		return PTR_ERR(esph);
-
-	esp->esph = esph;
-
-	return 0;
-}
-
-int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
-{
-	u8 *tail;
-	int nfrags;
-	int esph_offset;
-	struct page *page;
-	struct sk_buff *trailer;
-	int tailen = esp->tailen;
-
-	if (x->encap) {
-		int err = esp6_output_encap(x, skb, esp);
-
-		if (err < 0)
-			return err;
-	}
-
-	if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
-	    ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
-		goto cow;
-
-	if (!skb_cloned(skb)) {
-		if (tailen <= skb_tailroom(skb)) {
-			nfrags = 1;
-			trailer = skb;
-			tail = skb_tail_pointer(trailer);
-
-			goto skip_cow;
-		} else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
-			   && !skb_has_frag_list(skb)) {
-			int allocsize;
-			struct sock *sk = skb->sk;
-			struct page_frag *pfrag = &x->xfrag;
-
-			esp->inplace = false;
-
-			allocsize = ALIGN(tailen, L1_CACHE_BYTES);
-
-			spin_lock_bh(&x->lock);
-
-			if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
-				spin_unlock_bh(&x->lock);
-				goto cow;
-			}
-
-			page = pfrag->page;
-			get_page(page);
-
-			tail = page_address(page) + pfrag->offset;
-
-			esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
-
-			nfrags = skb_shinfo(skb)->nr_frags;
-
-			__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
-					     tailen);
-			skb_shinfo(skb)->nr_frags = ++nfrags;
-
-			pfrag->offset = pfrag->offset + allocsize;
-
-			spin_unlock_bh(&x->lock);
-
-			nfrags++;
-
-			skb->len += tailen;
-			skb->data_len += tailen;
-			skb->truesize += tailen;
-			if (sk && sk_fullsock(sk))
-				refcount_add(tailen, &sk->sk_wmem_alloc);
-
-			goto out;
-		}
-	}
-
-cow:
-	esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
-
-	nfrags = skb_cow_data(skb, tailen, &trailer);
-	if (nfrags < 0)
-		goto out;
-	tail = skb_tail_pointer(trailer);
-	esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
-
-skip_cow:
-	esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
-	pskb_put(skb, trailer, tailen);
-
-out:
-	return nfrags;
-}
-EXPORT_SYMBOL_GPL(esp6_output_head);
-
-int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
-{
-	u8 *iv;
-	int alen;
-	void *tmp;
-	int ivlen;
-	int assoclen;
-	int extralen;
-	struct page *page;
-	struct ip_esp_hdr *esph;
-	struct aead_request *req;
-	struct crypto_aead *aead;
-	struct scatterlist *sg, *dsg;
-	struct esp_output_extra *extra;
-	int err = -ENOMEM;
-
-	assoclen = sizeof(struct ip_esp_hdr);
-	extralen = 0;
-
-	if (x->props.flags & XFRM_STATE_ESN) {
-		extralen += sizeof(*extra);
-		assoclen += sizeof(__be32);
-	}
-
-	aead = x->data;
-	alen = crypto_aead_authsize(aead);
-	ivlen = crypto_aead_ivsize(aead);
-
-	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
-	if (!tmp)
-		goto error;
-
-	extra = esp_tmp_extra(tmp);
-	iv = esp_tmp_iv(aead, tmp, extralen);
-	req = esp_tmp_req(aead, iv);
-	sg = esp_req_sg(aead, req);
-
-	if (esp->inplace)
-		dsg = sg;
-	else
-		dsg = &sg[esp->nfrags];
-
-	esph = esp_output_set_esn(skb, x, esp->esph, extra);
-	esp->esph = esph;
-
-	sg_init_table(sg, esp->nfrags);
-	err = skb_to_sgvec(skb, sg,
-		           (unsigned char *)esph - skb->data,
-		           assoclen + ivlen + esp->clen + alen);
-	if (unlikely(err < 0))
-		goto error_free;
-
-	if (!esp->inplace) {
-		int allocsize;
-		struct page_frag *pfrag = &x->xfrag;
-
-		allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
-
-		spin_lock_bh(&x->lock);
-		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
-			spin_unlock_bh(&x->lock);
-			goto error_free;
-		}
-
-		skb_shinfo(skb)->nr_frags = 1;
-
-		page = pfrag->page;
-		get_page(page);
-		/* replace page frags in skb with new page */
-		__skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
-		pfrag->offset = pfrag->offset + allocsize;
-		spin_unlock_bh(&x->lock);
-
-		sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
-		err = skb_to_sgvec(skb, dsg,
-			           (unsigned char *)esph - skb->data,
-			           assoclen + ivlen + esp->clen + alen);
-		if (unlikely(err < 0))
-			goto error_free;
-	}
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		aead_request_set_callback(req, 0, esp_output_done_esn, skb);
-	else
-		aead_request_set_callback(req, 0, esp_output_done, skb);
-
-	aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
-	aead_request_set_ad(req, assoclen);
-
-	memset(iv, 0, ivlen);
-	memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
-	       min(ivlen, 8));
-
-	ESP_SKB_CB(skb)->tmp = tmp;
-	err = crypto_aead_encrypt(req);
-
-	switch (err) {
-	case -EINPROGRESS:
-		goto error;
-
-	case -ENOSPC:
-		err = NET_XMIT_DROP;
+	case UDP_ENCAP_ESPINUDP:
+		source = uh->source;
 		break;
-
-	case 0:
-		if ((x->props.flags & XFRM_STATE_ESN))
-			esp_output_restore_header(skb);
-		esp_output_encap_csum(skb);
-	}
-
-	if (sg != dsg)
-		esp_ssg_unref(x, tmp, skb);
-
-	if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
-		err = esp_output_tail_tcp(x, skb);
-
-error_free:
-	kfree(tmp);
-error:
-	return err;
-}
-EXPORT_SYMBOL_GPL(esp6_output_tail);
-
-static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
-{
-	int alen;
-	int blksize;
-	struct ip_esp_hdr *esph;
-	struct crypto_aead *aead;
-	struct esp_info esp;
-
-	esp.inplace = true;
-
-	esp.proto = *skb_mac_header(skb);
-	*skb_mac_header(skb) = IPPROTO_ESP;
-
-	/* skb is pure payload to encrypt */
-
-	aead = x->data;
-	alen = crypto_aead_authsize(aead);
-
-	esp.tfclen = 0;
-	if (x->tfcpad) {
-		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
-		u32 padto;
-
-		padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
-		if (skb->len < padto)
-			esp.tfclen = padto - skb->len;
-	}
-	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
-	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
-	esp.plen = esp.clen - skb->len - esp.tfclen;
-	esp.tailen = esp.tfclen + esp.plen + alen;
-
-	esp.esph = ip_esp_hdr(skb);
-
-	esp.nfrags = esp6_output_head(x, skb, &esp);
-	if (esp.nfrags < 0)
-		return esp.nfrags;
-
-	esph = esp.esph;
-	esph->spi = x->id.spi;
-
-	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
-	esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
-			    ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
-
-	skb_push(skb, -skb_network_offset(skb));
-
-	return esp6_output_tail(x, skb, &esp);
-}
-
-static inline int esp_remove_trailer(struct sk_buff *skb)
-{
-	struct xfrm_state *x = xfrm_input_state(skb);
-	struct crypto_aead *aead = x->data;
-	int alen, hlen, elen;
-	int padlen, trimlen;
-	__wsum csumdiff;
-	u8 nexthdr[2];
-	int ret;
-
-	alen = crypto_aead_authsize(aead);
-	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
-	elen = skb->len - hlen;
-
-	ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
-	BUG_ON(ret);
-
-	ret = -EINVAL;
-	padlen = nexthdr[0];
-	if (padlen + 2 + alen >= elen) {
-		net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
-				    padlen + 2, elen - alen);
-		goto out;
-	}
-
-	trimlen = alen + padlen + 2;
-	if (skb->ip_summed == CHECKSUM_COMPLETE) {
-		csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
-		skb->csum = csum_block_sub(skb->csum, csumdiff,
-					   skb->len - trimlen);
-	}
-	ret = pskb_trim(skb, skb->len - trimlen);
-	if (unlikely(ret))
-		return ret;
-
-	ret = nexthdr[1];
-
-out:
-	return ret;
-}
-
-int esp6_input_done2(struct sk_buff *skb, int err)
-{
-	struct xfrm_state *x = xfrm_input_state(skb);
-	struct xfrm_offload *xo = xfrm_offload(skb);
-	struct crypto_aead *aead = x->data;
-	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
-	int hdr_len = skb_network_header_len(skb);
-
-	if (!xo || !(xo->flags & CRYPTO_DONE))
-		kfree(ESP_SKB_CB(skb)->tmp);
-
-	if (unlikely(err))
-		goto out;
-
-	err = esp_remove_trailer(skb);
-	if (unlikely(err < 0))
-		goto out;
-
-	if (x->encap) {
-		const struct ipv6hdr *ip6h = ipv6_hdr(skb);
-		int offset = skb_network_offset(skb) + sizeof(*ip6h);
-		struct xfrm_encap_tmpl *encap = x->encap;
-		u8 nexthdr = ip6h->nexthdr;
-		__be16 frag_off, source;
-		struct udphdr *uh;
-		struct tcphdr *th;
-
-		offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
-		if (offset == -1) {
-			err = -EINVAL;
-			goto out;
-		}
-
-		uh = (void *)(skb->data + offset);
-		th = (void *)(skb->data + offset);
-		hdr_len += offset;
-
-		switch (x->encap->encap_type) {
-		case TCP_ENCAP_ESPINTCP:
-			source = th->source;
-			break;
-		case UDP_ENCAP_ESPINUDP:
-			source = uh->source;
-			break;
-		default:
-			WARN_ON_ONCE(1);
-			err = -EINVAL;
-			goto out;
-		}
-
-		/*
-		 * 1) if the NAT-T peer's IP or port changed then
-		 *    advertise the change to the keying daemon.
-		 *    This is an inbound SA, so just compare
-		 *    SRC ports.
-		 */
-		if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
-		    source != encap->encap_sport) {
-			xfrm_address_t ipaddr;
-
-			memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
-			km_new_mapping(x, &ipaddr, source);
-
-			/* XXX: perhaps add an extra
-			 * policy check here, to see
-			 * if we should allow or
-			 * reject a packet from a
-			 * different source
-			 * address/port.
-			 */
-		}
-
-		/*
-		 * 2) ignore UDP/TCP checksums in case
-		 *    of NAT-T in Transport Mode, or
-		 *    perform other post-processing fixes
-		 *    as per draft-ietf-ipsec-udp-encaps-06,
-		 *    section 3.1.2
-		 */
-		if (x->props.mode == XFRM_MODE_TRANSPORT)
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
+	default:
+		WARN_ON_ONCE(1);
+		return -1;
 	}
 
-	skb_postpull_rcsum(skb, skb_network_header(skb),
-			   skb_network_header_len(skb));
-	skb_pull_rcsum(skb, hlen);
-	if (x->props.mode == XFRM_MODE_TUNNEL ||
-	    x->props.mode == XFRM_MODE_IPTFS)
-		skb_reset_transport_header(skb);
-	else
-		skb_set_transport_header(skb, -hdr_len);
-
-	/* RFC4303: Drop dummy packets without any error */
-	if (err == IPPROTO_NONE)
-		err = -EINVAL;
-
-out:
-	return err;
-}
-EXPORT_SYMBOL_GPL(esp6_input_done2);
-
-static void esp_input_done(void *data, int err)
-{
-	struct sk_buff *skb = data;
-
-	xfrm_input_resume(skb, esp6_input_done2(skb, err));
-}
-
-static void esp_input_restore_header(struct sk_buff *skb)
-{
-	esp_restore_header(skb, 0);
-	__skb_pull(skb, 4);
-}
-
-static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
-{
-	struct xfrm_state *x = xfrm_input_state(skb);
-
-	/* For ESN we move the header forward by 4 bytes to
-	 * accommodate the high bits.  We will move it back after
-	 * decryption.
+	/*
+	 * 1) if the NAT-T peer's IP or port changed then
+	 *    advertise the change to the keying daemon.
+	 *    This is an inbound SA, so just compare
+	 *    SRC ports.
 	 */
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		struct ip_esp_hdr *esph = skb_push(skb, 4);
-
-		*seqhi = esph->spi;
-		esph->spi = esph->seq_no;
-		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
-	}
-}
-
-static void esp_input_done_esn(void *data, int err)
-{
-	struct sk_buff *skb = data;
-
-	esp_input_restore_header(skb);
-	esp_input_done(data, err);
-}
-
-static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
-{
-	struct crypto_aead *aead = x->data;
-	struct aead_request *req;
-	struct sk_buff *trailer;
-	int ivlen = crypto_aead_ivsize(aead);
-	int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
-	int nfrags;
-	int assoclen;
-	int seqhilen;
-	int ret = 0;
-	void *tmp;
-	__be32 *seqhi;
-	u8 *iv;
-	struct scatterlist *sg;
-
-	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	if (elen <= 0) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	assoclen = sizeof(struct ip_esp_hdr);
-	seqhilen = 0;
-
-	if (x->props.flags & XFRM_STATE_ESN) {
-		seqhilen += sizeof(__be32);
-		assoclen += seqhilen;
-	}
-
-	if (!skb_cloned(skb)) {
-		if (!skb_is_nonlinear(skb)) {
-			nfrags = 1;
-
-			goto skip_cow;
-		} else if (!skb_has_frag_list(skb)) {
-			nfrags = skb_shinfo(skb)->nr_frags;
-			nfrags++;
-
-			goto skip_cow;
-		}
-	}
-
-	nfrags = skb_cow_data(skb, 0, &trailer);
-	if (nfrags < 0) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
+	    source != encap->encap_sport) {
+		xfrm_address_t ipaddr;
 
-skip_cow:
-	ret = -ENOMEM;
-	tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
-	if (!tmp)
-		goto out;
-
-	ESP_SKB_CB(skb)->tmp = tmp;
-	seqhi = esp_tmp_extra(tmp);
-	iv = esp_tmp_iv(aead, tmp, seqhilen);
-	req = esp_tmp_req(aead, iv);
-	sg = esp_req_sg(aead, req);
-
-	esp_input_set_header(skb, seqhi);
-
-	sg_init_table(sg, nfrags);
-	ret = skb_to_sgvec(skb, sg, 0, skb->len);
-	if (unlikely(ret < 0)) {
-		kfree(tmp);
-		goto out;
+		memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
+		km_new_mapping(x, &ipaddr, source);
 	}
 
-	skb->ip_summed = CHECKSUM_NONE;
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		aead_request_set_callback(req, 0, esp_input_done_esn, skb);
-	else
-		aead_request_set_callback(req, 0, esp_input_done, skb);
-
-	aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
-	aead_request_set_ad(req, assoclen);
-
-	ret = crypto_aead_decrypt(req);
-	if (ret == -EINPROGRESS)
-		goto out;
-
-	if ((x->props.flags & XFRM_STATE_ESN))
-		esp_input_restore_header(skb);
-
-	ret = esp6_input_done2(skb, ret);
+	/*
+	 * 2) ignore UDP/TCP checksums in case
+	 *    of NAT-T in Transport Mode, or
+	 *    perform other post-processing fixes
+	 *    as per draft-ietf-ipsec-udp-encaps-06,
+	 *    section 3.1.2
+	 */
+	if (x->props.mode == XFRM_MODE_TRANSPORT)
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-out:
 	return ret;
 }
 
@@ -1000,146 +159,6 @@ static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	return 0;
 }
 
-static void esp6_destroy(struct xfrm_state *x)
-{
-	struct crypto_aead *aead = x->data;
-
-	if (!aead)
-		return;
-
-	crypto_free_aead(aead);
-}
-
-static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
-{
-	char aead_name[CRYPTO_MAX_ALG_NAME];
-	struct crypto_aead *aead;
-	int err;
-
-	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
-		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
-		NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-		return -ENAMETOOLONG;
-	}
-
-	aead = crypto_alloc_aead(aead_name, 0, 0);
-	err = PTR_ERR(aead);
-	if (IS_ERR(aead))
-		goto error;
-
-	x->data = aead;
-
-	err = crypto_aead_setkey(aead, x->aead->alg_key,
-				 (x->aead->alg_key_len + 7) / 8);
-	if (err)
-		goto error;
-
-	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
-	if (err)
-		goto error;
-
-	return 0;
-
-error:
-	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-	return err;
-}
-
-static int esp_init_authenc(struct xfrm_state *x,
-			    struct netlink_ext_ack *extack)
-{
-	struct crypto_aead *aead;
-	struct crypto_authenc_key_param *param;
-	struct rtattr *rta;
-	char *key;
-	char *p;
-	char authenc_name[CRYPTO_MAX_ALG_NAME];
-	unsigned int keylen;
-	int err;
-
-	err = -ENAMETOOLONG;
-
-	if ((x->props.flags & XFRM_STATE_ESN)) {
-		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
-			     "%s%sauthencesn(%s,%s)%s",
-			     x->geniv ?: "", x->geniv ? "(" : "",
-			     x->aalg ? x->aalg->alg_name : "digest_null",
-			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
-			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-			goto error;
-		}
-	} else {
-		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
-			     "%s%sauthenc(%s,%s)%s",
-			     x->geniv ?: "", x->geniv ? "(" : "",
-			     x->aalg ? x->aalg->alg_name : "digest_null",
-			     x->ealg->alg_name,
-			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
-			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
-			goto error;
-		}
-	}
-
-	aead = crypto_alloc_aead(authenc_name, 0, 0);
-	err = PTR_ERR(aead);
-	if (IS_ERR(aead)) {
-		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-		goto error;
-	}
-
-	x->data = aead;
-
-	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
-		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
-	err = -ENOMEM;
-	key = kmalloc(keylen, GFP_KERNEL);
-	if (!key)
-		goto error;
-
-	p = key;
-	rta = (void *)p;
-	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
-	rta->rta_len = RTA_LENGTH(sizeof(*param));
-	param = RTA_DATA(rta);
-	p += RTA_SPACE(sizeof(*param));
-
-	if (x->aalg) {
-		struct xfrm_algo_desc *aalg_desc;
-
-		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
-		p += (x->aalg->alg_key_len + 7) / 8;
-
-		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
-		BUG_ON(!aalg_desc);
-
-		err = -EINVAL;
-		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
-		    crypto_aead_authsize(aead)) {
-			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-			goto free_key;
-		}
-
-		err = crypto_aead_setauthsize(
-			aead, x->aalg->alg_trunc_len / 8);
-		if (err) {
-			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
-			goto free_key;
-		}
-	}
-
-	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
-	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
-
-	err = crypto_aead_setkey(aead, key, keylen);
-
-free_key:
-	kfree(key);
-
-error:
-	return err;
-}
-
 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
 {
 	struct crypto_aead *aead;
@@ -1213,13 +232,16 @@ static int esp6_rcv_cb(struct sk_buff *skb, int err)
 }
 
 static const struct xfrm_type esp6_type = {
-	.owner		= THIS_MODULE,
-	.proto		= IPPROTO_ESP,
-	.flags		= XFRM_TYPE_REPLAY_PROT,
-	.init_state	= esp6_init_state,
-	.destructor	= esp6_destroy,
-	.input		= esp6_input,
-	.output		= esp6_output,
+	.owner			= THIS_MODULE,
+	.proto			= IPPROTO_ESP,
+	.flags			= XFRM_TYPE_REPLAY_PROT,
+	.init_state		= esp6_init_state,
+	.destructor		= esp_destroy,
+	.input			= esp_input,
+	.input_encap		= esp6_input_encap,
+	.output			= esp_output,
+	.find_tcp_sk		= esp6_find_tcp_sk,
+	.output_encap_csum	= esp6_output_encap_csum,
 };
 
 static struct xfrm6_protocol esp6_protocol = {
diff --git a/net/ipv6/esp6_offload.c b/net/ipv6/esp6_offload.c
index 22895521a57d..b1c38d7d286e 100644
--- a/net/ipv6/esp6_offload.c
+++ b/net/ipv6/esp6_offload.c
@@ -290,14 +290,18 @@ static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct crypto_aead *aead = x->data;
 	struct xfrm_offload *xo = xfrm_offload(skb);
+	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 
-	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
+	if (!pskb_may_pull(skb, hlen))
 		return -EINVAL;
 
 	if (!(xo->flags & CRYPTO_DONE))
 		skb->ip_summed = CHECKSUM_NONE;
+	else
+		skb_postpull_rcsum(skb, skb_network_header(skb),
+				   skb_network_header_len(skb));
 
-	return esp6_input_done2(skb, 0);
+	return esp_input_done2(skb, 0);
 }
 
 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
@@ -340,7 +344,7 @@ static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features
 	esp.tailen = esp.tfclen + esp.plen + alen;
 
 	if (!hw_offload || !skb_is_gso(skb)) {
-		esp.nfrags = esp6_output_head(x, skb, &esp);
+		esp.nfrags = esp_output_head(x, skb, &esp);
 		if (esp.nfrags < 0)
 			return esp.nfrags;
 	}
@@ -384,7 +388,7 @@ static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features
 		return 0;
 	}
 
-	err = esp6_output_tail(x, skb, &esp);
+	err = esp_output_tail(x, skb, &esp);
 	if (err)
 		return err;
 
diff --git a/net/xfrm/Makefile b/net/xfrm/Makefile
index 5a1787587cb3..2a8995a34bdd 100644
--- a/net/xfrm/Makefile
+++ b/net/xfrm/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_XFRM_INTERFACE) += xfrm_interface.o
 obj-$(CONFIG_XFRM_IPTFS) += xfrm_iptfs.o
 obj-$(CONFIG_XFRM_ESPINTCP) += espintcp.o
 obj-$(CONFIG_DEBUG_INFO_BTF) += xfrm_state_bpf.o
+obj-$(CONFIG_XFRM_ESP) += xfrm_esp.o
diff --git a/net/xfrm/xfrm_esp.c b/net/xfrm/xfrm_esp.c
new file mode 100644
index 000000000000..4f75e1ace3bb
--- /dev/null
+++ b/net/xfrm/xfrm_esp.c
@@ -0,0 +1,1012 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <crypto/aead.h>
+#include <crypto/authenc.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <net/ip.h>
+#include <net/xfrm.h>
+#include <net/esp.h>
+#include <linux/scatterlist.h>
+#include <linux/kernel.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/in6.h>
+#include <net/icmp.h>
+#include <net/protocol.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+#include <net/espintcp.h>
+#include <linux/skbuff_ref.h>
+
+#include <linux/highmem.h>
+
+struct esp_skb_cb {
+	struct xfrm_skb_cb xfrm;
+	void *tmp;
+};
+
+struct esp_output_extra {
+	__be32 seqhi;
+	u32 esphoff;
+};
+
+#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
+
+/*
+ * Allocate an AEAD request structure with extra space for SG and IV.
+ *
+ * For alignment considerations the IV is placed at the front, followed
+ * by the request and finally the SG list.
+ *
+ * TODO: Use spare space in skb for this where possible.
+ */
+static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
+{
+	unsigned int len;
+
+	len = extralen;
+
+	len += crypto_aead_ivsize(aead);
+
+	if (len) {
+		len += crypto_aead_alignmask(aead) &
+		       ~(crypto_tfm_ctx_alignment() - 1);
+		len = ALIGN(len, crypto_tfm_ctx_alignment());
+	}
+
+	len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
+	len = ALIGN(len, __alignof__(struct scatterlist));
+
+	len += sizeof(struct scatterlist) * nfrags;
+
+	return kmalloc(len, GFP_ATOMIC);
+}
+
+static inline void *esp_tmp_extra(void *tmp)
+{
+	return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
+}
+
+static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
+{
+	return crypto_aead_ivsize(aead) ?
+	       PTR_ALIGN((u8 *)tmp + extralen,
+			 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
+}
+
+static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
+{
+	struct aead_request *req;
+
+	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
+				crypto_tfm_ctx_alignment());
+	aead_request_set_tfm(req, aead);
+	return req;
+}
+
+static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
+					     struct aead_request *req)
+{
+	return (void *)ALIGN((unsigned long)(req + 1) +
+			     crypto_aead_reqsize(aead),
+			     __alignof__(struct scatterlist));
+}
+
+static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
+{
+	struct crypto_aead *aead = x->data;
+	int extralen = 0;
+	u8 *iv;
+	struct aead_request *req;
+	struct scatterlist *sg;
+
+	if (x->props.flags & XFRM_STATE_ESN)
+		extralen += sizeof(struct esp_output_extra);
+
+	iv = esp_tmp_iv(aead, tmp, extralen);
+	req = esp_tmp_req(aead, iv);
+
+	/* Unref skb_frag_pages in the src scatterlist if necessary.
+	 * Skip the first sg which comes from skb->data.
+	 */
+	if (req->src != req->dst)
+		for (sg = sg_next(req->src); sg; sg = sg_next(sg))
+			skb_page_unref(page_to_netmem(sg_page(sg)),
+				       skb->pp_recycle);
+}
+
+#ifdef CONFIG_INET_ESPINTCP
+static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct sock *sk;
+	int err;
+
+	rcu_read_lock();
+
+	sk = x->type->find_tcp_sk(x);
+	err = PTR_ERR_OR_ZERO(sk);
+	if (err) {
+		kfree_skb(skb);
+		goto out;
+	}
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk))
+		err = espintcp_queue_out(sk, skb);
+	else
+		err = espintcp_push_skb(sk, skb);
+	bh_unlock_sock(sk);
+
+	sock_put(sk);
+
+out:
+	rcu_read_unlock();
+	return err;
+}
+
+static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
+				   struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	struct xfrm_state *x = dst->xfrm;
+
+	return esp_output_tcp_finish(x, skb);
+}
+
+static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int err;
+
+	local_bh_disable();
+	err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
+	local_bh_enable();
+
+	/* EINPROGRESS just happens to do the right thing.  It
+	 * actually means that the skb has been consumed and
+	 * isn't coming back.
+	 */
+	return err ?: -EINPROGRESS;
+}
+#else
+static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
+{
+	WARN_ON(1);
+	return -EOPNOTSUPP;
+}
+#endif
+
+static void esp_output_done(void *data, int err)
+{
+	struct sk_buff *skb = data;
+	struct xfrm_offload *xo = xfrm_offload(skb);
+	void *tmp;
+	struct xfrm_state *x;
+
+	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
+		struct sec_path *sp = skb_sec_path(skb);
+
+		x = sp->xvec[sp->len - 1];
+	} else {
+		x = skb_dst(skb)->xfrm;
+	}
+
+	tmp = ESP_SKB_CB(skb)->tmp;
+	esp_ssg_unref(x, tmp, skb);
+	kfree(tmp);
+
+	x->type->output_encap_csum(skb);
+
+	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
+		if (err) {
+			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
+			kfree_skb(skb);
+			return;
+		}
+
+		skb_push(skb, skb->data - skb_mac_header(skb));
+		secpath_reset(skb);
+		xfrm_dev_resume(skb);
+	} else {
+		if (!err &&
+		    x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) {
+			err = esp_output_tail_tcp(x, skb);
+			if (err != -EINPROGRESS)
+				kfree_skb(skb);
+		} else {
+			xfrm_output_resume(skb_to_full_sk(skb), skb, err);
+		}
+	}
+}
+
+/* Move ESP header back into place. */
+static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
+{
+	struct ip_esp_hdr *esph = (void *)(skb->data + offset);
+	void *tmp = ESP_SKB_CB(skb)->tmp;
+	__be32 *seqhi = esp_tmp_extra(tmp);
+
+	esph->seq_no = esph->spi;
+	esph->spi = *seqhi;
+}
+
+static void esp_output_restore_header(struct sk_buff *skb)
+{
+	void *tmp = ESP_SKB_CB(skb)->tmp;
+	struct esp_output_extra *extra = esp_tmp_extra(tmp);
+
+	esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
+				sizeof(__be32));
+}
+
+static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
+					     struct xfrm_state *x,
+					     struct ip_esp_hdr *esph,
+					     struct esp_output_extra *extra)
+{
+	/* For ESN we move the header forward by 4 bytes to
+	 * accommodate the high bits.  We will move it back after
+	 * encryption.
+	 */
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		__u32 seqhi;
+		struct xfrm_offload *xo = xfrm_offload(skb);
+
+		if (xo)
+			seqhi = xo->seq.hi;
+		else
+			seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
+
+		extra->esphoff = (unsigned char *)esph -
+				 skb_transport_header(skb);
+		esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
+		extra->seqhi = esph->spi;
+		esph->seq_no = htonl(seqhi);
+	}
+
+	esph->spi = x->id.spi;
+
+	return esph;
+}
+
+static void esp_output_done_esn(void *data, int err)
+{
+	struct sk_buff *skb = data;
+
+	esp_output_restore_header(skb);
+	esp_output_done(data, err);
+}
+
+static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
+					       int encap_type,
+					       struct esp_info *esp,
+					       __be16 sport,
+					       __be16 dport)
+{
+	struct udphdr *uh;
+	unsigned int len;
+	struct xfrm_offload *xo = xfrm_offload(skb);
+
+	len = skb->len + esp->tailen - skb_transport_offset(skb);
+
+	uh = (struct udphdr *)esp->esph;
+	uh->source = sport;
+	uh->dest = dport;
+	uh->len = htons(len);
+	uh->check = 0;
+
+	/* For ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
+	 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
+	 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
+	 */
+	if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
+		*skb_mac_header(skb) = IPPROTO_UDP;
+
+	return (struct ip_esp_hdr *)(uh + 1);
+}
+
+#ifdef CONFIG_INET_ESPINTCP
+static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
+					       struct sk_buff *skb,
+					       struct esp_info *esp)
+{
+	__be16 *lenp = (void *)esp->esph;
+	struct ip_esp_hdr *esph;
+	unsigned int len;
+	struct sock *sk;
+
+	len = skb->len + esp->tailen - skb_transport_offset(skb);
+
+	rcu_read_lock();
+	sk = x->type->find_tcp_sk(x);
+	rcu_read_unlock();
+
+	if (IS_ERR(sk))
+		return ERR_CAST(sk);
+
+	sock_put(sk);
+
+	*lenp = htons(len);
+	esph = (struct ip_esp_hdr *)(lenp + 1);
+
+	return esph;
+}
+#else
+static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
+					       struct sk_buff *skb,
+					       struct esp_info *esp)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+#endif
+
+static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
+			    struct esp_info *esp)
+{
+	struct xfrm_encap_tmpl *encap = x->encap;
+	struct ip_esp_hdr *esph;
+	__be16 sport, dport;
+	int encap_type;
+
+	esph = ERR_PTR(-EOPNOTSUPP);
+
+	spin_lock_bh(&x->lock);
+	sport = encap->encap_sport;
+	dport = encap->encap_dport;
+	encap_type = encap->encap_type;
+	spin_unlock_bh(&x->lock);
+
+	switch (encap_type) {
+	default:
+	case UDP_ENCAP_ESPINUDP:
+		esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
+		break;
+	case TCP_ENCAP_ESPINTCP:
+		esph = esp_output_tcp_encap(x, skb, esp);
+		break;
+	}
+
+	if (IS_ERR(esph))
+		return PTR_ERR(esph);
+
+	esp->esph = esph;
+
+	return 0;
+}
+
+int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
+{
+	u8 *tail;
+	int nfrags;
+	int esph_offset;
+	struct page *page;
+	struct sk_buff *trailer;
+	int tailen = esp->tailen;
+
+	/* this is non-NULL only with TCP/UDP Encapsulation */
+	if (x->encap) {
+		int err = esp_output_encap(x, skb, esp);
+
+		if (err < 0)
+			return err;
+	}
+
+	if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
+	    ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
+		goto cow;
+
+	if (!skb_cloned(skb)) {
+		if (tailen <= skb_tailroom(skb)) {
+			nfrags = 1;
+			trailer = skb;
+			tail = skb_tail_pointer(trailer);
+
+			goto skip_cow;
+		} else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) &&
+			    !skb_has_frag_list(skb)) {
+			int allocsize;
+			struct sock *sk = skb->sk;
+			struct page_frag *pfrag = &x->xfrag;
+
+			esp->inplace = false;
+
+			allocsize = ALIGN(tailen, L1_CACHE_BYTES);
+
+			spin_lock_bh(&x->lock);
+
+			if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
+				spin_unlock_bh(&x->lock);
+				goto cow;
+			}
+
+			page = pfrag->page;
+			get_page(page);
+
+			tail = page_address(page) + pfrag->offset;
+
+			esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
+
+			nfrags = skb_shinfo(skb)->nr_frags;
+
+			__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
+					     tailen);
+			skb_shinfo(skb)->nr_frags = ++nfrags;
+
+			pfrag->offset = pfrag->offset + allocsize;
+
+			spin_unlock_bh(&x->lock);
+
+			nfrags++;
+
+			skb_len_add(skb, tailen);
+			if (sk && sk_fullsock(sk))
+				refcount_add(tailen, &sk->sk_wmem_alloc);
+
+			goto out;
+		}
+	}
+
+cow:
+	esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
+
+	nfrags = skb_cow_data(skb, tailen, &trailer);
+	if (nfrags < 0)
+		goto out;
+	tail = skb_tail_pointer(trailer);
+	esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
+
+skip_cow:
+	esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
+	pskb_put(skb, trailer, tailen);
+
+out:
+	return nfrags;
+}
+EXPORT_SYMBOL_GPL(esp_output_head);
+
+int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
+{
+	u8 *iv;
+	int alen;
+	void *tmp;
+	int ivlen;
+	int assoclen;
+	int extralen;
+	struct page *page;
+	struct ip_esp_hdr *esph;
+	struct crypto_aead *aead;
+	struct aead_request *req;
+	struct scatterlist *sg, *dsg;
+	struct esp_output_extra *extra;
+	int err = -ENOMEM;
+
+	assoclen = sizeof(struct ip_esp_hdr);
+	extralen = 0;
+
+	if (x->props.flags & XFRM_STATE_ESN) {
+		extralen += sizeof(*extra);
+		assoclen += sizeof(__be32);
+	}
+
+	aead = x->data;
+	alen = crypto_aead_authsize(aead);
+	ivlen = crypto_aead_ivsize(aead);
+
+	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
+	if (!tmp)
+		goto error;
+
+	extra = esp_tmp_extra(tmp);
+	iv = esp_tmp_iv(aead, tmp, extralen);
+	req = esp_tmp_req(aead, iv);
+	sg = esp_req_sg(aead, req);
+
+	if (esp->inplace)
+		dsg = sg;
+	else
+		dsg = &sg[esp->nfrags];
+
+	esph = esp_output_set_esn(skb, x, esp->esph, extra);
+	esp->esph = esph;
+
+	sg_init_table(sg, esp->nfrags);
+	err = skb_to_sgvec(skb, sg,
+			   (unsigned char *)esph - skb->data,
+			    assoclen + ivlen + esp->clen + alen);
+	if (unlikely(err < 0))
+		goto error_free;
+
+	if (!esp->inplace) {
+		int allocsize;
+		struct page_frag *pfrag = &x->xfrag;
+
+		allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
+
+		spin_lock_bh(&x->lock);
+		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
+			spin_unlock_bh(&x->lock);
+			goto error_free;
+		}
+
+		skb_shinfo(skb)->nr_frags = 1;
+
+		page = pfrag->page;
+		get_page(page);
+		/* replace page frags in skb with new page */
+		__skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
+		pfrag->offset = pfrag->offset + allocsize;
+		spin_unlock_bh(&x->lock);
+
+		sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
+		err = skb_to_sgvec(skb, dsg,
+				   (unsigned char *)esph - skb->data,
+				    assoclen + ivlen + esp->clen + alen);
+		if (unlikely(err < 0))
+			goto error_free;
+	}
+
+	if ((x->props.flags & XFRM_STATE_ESN))
+		aead_request_set_callback(req, 0, esp_output_done_esn, skb);
+	else
+		aead_request_set_callback(req, 0, esp_output_done, skb);
+
+	aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
+	aead_request_set_ad(req, assoclen);
+
+	memset(iv, 0, ivlen);
+	memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
+	       min(ivlen, 8));
+
+	ESP_SKB_CB(skb)->tmp = tmp;
+	err = crypto_aead_encrypt(req);
+
+	switch (err) {
+	case -EINPROGRESS:
+		goto error;
+
+	case -ENOSPC:
+		err = NET_XMIT_DROP;
+		break;
+
+	case 0:
+		if ((x->props.flags & XFRM_STATE_ESN))
+			esp_output_restore_header(skb);
+		x->type->output_encap_csum(skb);
+	}
+
+	if (sg != dsg)
+		esp_ssg_unref(x, tmp, skb);
+
+	if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
+		err = esp_output_tail_tcp(x, skb);
+
+error_free:
+	kfree(tmp);
+error:
+	return err;
+}
+EXPORT_SYMBOL_GPL(esp_output_tail);
+
+int esp_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+	int alen;
+	int blksize;
+	struct ip_esp_hdr *esph;
+	struct crypto_aead *aead;
+	struct esp_info esp;
+
+	esp.inplace = true;
+
+	esp.proto = *skb_mac_header(skb);
+	*skb_mac_header(skb) = IPPROTO_ESP;
+
+	/* skb is pure payload to encrypt */
+
+	aead = x->data;
+	alen = crypto_aead_authsize(aead);
+
+	esp.tfclen = 0;
+	if (x->tfcpad) {
+		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
+		u32 padto;
+
+		padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
+		if (skb->len < padto)
+			esp.tfclen = padto - skb->len;
+	}
+	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
+	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
+	esp.plen = esp.clen - skb->len - esp.tfclen;
+	esp.tailen = esp.tfclen + esp.plen + alen;
+
+	esp.esph = ip_esp_hdr(skb);
+
+	esp.nfrags = esp_output_head(x, skb, &esp);
+	if (esp.nfrags < 0)
+		return esp.nfrags;
+
+	esph = esp.esph;
+	esph->spi = x->id.spi;
+
+	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
+	esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
+				 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
+
+	skb_push(skb, -skb_network_offset(skb));
+
+	return esp_output_tail(x, skb, &esp);
+}
+EXPORT_SYMBOL_GPL(esp_output);
+
+static inline int esp_remove_trailer(struct sk_buff *skb)
+{
+	struct xfrm_state *x = xfrm_input_state(skb);
+	struct crypto_aead *aead = x->data;
+	int alen, hlen, elen;
+	int padlen, trimlen;
+	__wsum csumdiff;
+	u8 nexthdr[2];
+	int ret;
+
+	alen = crypto_aead_authsize(aead);
+	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
+	elen = skb->len - hlen;
+
+	if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
+		BUG();
+
+	ret = -EINVAL;
+	padlen = nexthdr[0];
+	if (padlen + 2 + alen >= elen) {
+		net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
+				    padlen + 2, elen - alen);
+		goto out;
+	}
+
+	trimlen = alen + padlen + 2;
+	if (skb->ip_summed == CHECKSUM_COMPLETE) {
+		csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
+		skb->csum = csum_block_sub(skb->csum, csumdiff,
+					   skb->len - trimlen);
+	}
+	ret = pskb_trim(skb, skb->len - trimlen);
+	if (unlikely(ret))
+		return ret;
+
+	ret = nexthdr[1];
+
+out:
+	return ret;
+}
+
+int esp_input_done2(struct sk_buff *skb, int err)
+{
+	struct xfrm_state *x = xfrm_input_state(skb);
+	struct xfrm_offload *xo = xfrm_offload(skb);
+	struct crypto_aead *aead = x->data;
+	int hdr_len = skb_network_header_len(skb);
+	int nexthdr;
+	int hlen;
+
+	if (!xo || !(xo->flags & CRYPTO_DONE))
+		kfree(ESP_SKB_CB(skb)->tmp);
+
+	if (unlikely(err))
+		goto out;
+
+	err = esp_remove_trailer(skb);
+	if (unlikely(err < 0))
+		goto out;
+
+	nexthdr = err;
+
+	if (x->encap) {
+		hdr_len = x->type->input_encap(skb, x);
+		if (unlikely(hdr_len == -1)) {
+			err = -EINVAL;
+			goto out;
+		}
+	}
+
+	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
+	skb_pull_rcsum(skb, hlen);
+
+	if (x->props.mode == XFRM_MODE_TUNNEL ||
+	    x->props.mode == XFRM_MODE_IPTFS)
+		skb_reset_transport_header(skb);
+	else
+		skb_set_transport_header(skb, -hdr_len);
+
+	/* RFC4303: Drop dummy packets without any error */
+	if (nexthdr == IPPROTO_NONE)
+		err = -EINVAL;
+	else
+		err = nexthdr;
+
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(esp_input_done2);
+
+static void esp_input_done(void *data, int err)
+{
+	struct sk_buff *skb = data;
+
+	xfrm_input_resume(skb, esp_input_done2(skb, err));
+}
+
+static void esp_input_restore_header(struct sk_buff *skb)
+{
+	esp_restore_header(skb, 0);
+	__skb_pull(skb, 4);
+}
+
+static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
+{
+	struct xfrm_state *x = xfrm_input_state(skb);
+	struct ip_esp_hdr *esph;
+
+	/* For ESN we move the header forward by 4 bytes to
+	 * accommodate the high bits.  We will move it back after
+	 * decryption.
+	 */
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		esph = skb_push(skb, 4);
+		*seqhi = esph->spi;
+		esph->spi = esph->seq_no;
+		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
+	}
+}
+
+static void esp_input_done_esn(void *data, int err)
+{
+	struct sk_buff *skb = data;
+
+	esp_input_restore_header(skb);
+	esp_input_done(data, err);
+}
+
+/*
+ * Note: detecting truncated vs. non-truncated authentication data is very
+ * expensive, so we only support truncated data, which is the recommended
+ * and common case.
+ */
+int esp_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+	struct crypto_aead *aead = x->data;
+	struct aead_request *req;
+	struct sk_buff *trailer;
+	int ivlen = crypto_aead_ivsize(aead);
+	int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
+	int nfrags;
+	int assoclen;
+	int seqhilen;
+	__be32 *seqhi;
+	void *tmp;
+	u8 *iv;
+	struct scatterlist *sg;
+	int err = -EINVAL;
+
+	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
+		goto out;
+
+	if (elen <= 0)
+		goto out;
+
+	assoclen = sizeof(struct ip_esp_hdr);
+	seqhilen = 0;
+
+	if (x->props.flags & XFRM_STATE_ESN) {
+		seqhilen += sizeof(__be32);
+		assoclen += seqhilen;
+	}
+
+	if (!skb_cloned(skb)) {
+		if (!skb_is_nonlinear(skb)) {
+			nfrags = 1;
+
+			goto skip_cow;
+		} else if (!skb_has_frag_list(skb)) {
+			nfrags = skb_shinfo(skb)->nr_frags;
+			nfrags++;
+
+			goto skip_cow;
+		}
+	}
+
+	err = skb_cow_data(skb, 0, &trailer);
+	if (err < 0)
+		goto out;
+
+	nfrags = err;
+
+skip_cow:
+	err = -ENOMEM;
+	tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
+	if (!tmp)
+		goto out;
+
+	ESP_SKB_CB(skb)->tmp = tmp;
+	seqhi = esp_tmp_extra(tmp);
+	iv = esp_tmp_iv(aead, tmp, seqhilen);
+	req = esp_tmp_req(aead, iv);
+	sg = esp_req_sg(aead, req);
+
+	esp_input_set_header(skb, seqhi);
+
+	sg_init_table(sg, nfrags);
+	err = skb_to_sgvec(skb, sg, 0, skb->len);
+	if (unlikely(err < 0)) {
+		kfree(tmp);
+		goto out;
+	}
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	if ((x->props.flags & XFRM_STATE_ESN))
+		aead_request_set_callback(req, 0, esp_input_done_esn, skb);
+	else
+		aead_request_set_callback(req, 0, esp_input_done, skb);
+
+	aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
+	aead_request_set_ad(req, assoclen);
+
+	err = crypto_aead_decrypt(req);
+	if (err == -EINPROGRESS)
+		goto out;
+
+	if ((x->props.flags & XFRM_STATE_ESN))
+		esp_input_restore_header(skb);
+
+	err = esp_input_done2(skb, err);
+
+out:
+	return err;
+}
+EXPORT_SYMBOL_GPL(esp_input);
+
+void esp_destroy(struct xfrm_state *x)
+{
+	struct crypto_aead *aead = x->data;
+
+	if (!aead)
+		return;
+
+	crypto_free_aead(aead);
+}
+EXPORT_SYMBOL_GPL(esp_destroy);
+
+int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
+{
+	char aead_name[CRYPTO_MAX_ALG_NAME];
+	struct crypto_aead *aead;
+	int err;
+
+	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
+		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
+		NL_SET_ERR_MSG(extack, "Algorithm name is too long");
+		return -ENAMETOOLONG;
+	}
+
+	aead = crypto_alloc_aead(aead_name, 0, 0);
+	err = PTR_ERR(aead);
+	if (IS_ERR(aead))
+		goto error;
+
+	x->data = aead;
+
+	err = crypto_aead_setkey(aead, x->aead->alg_key,
+				 (x->aead->alg_key_len + 7) / 8);
+	if (err)
+		goto error;
+
+	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
+	if (err)
+		goto error;
+
+	return 0;
+
+error:
+	NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
+	return err;
+}
+EXPORT_SYMBOL_GPL(esp_init_aead);
+
+int esp_init_authenc(struct xfrm_state *x, struct netlink_ext_ack *extack)
+{
+	struct crypto_aead *aead;
+	struct crypto_authenc_key_param *param;
+	struct rtattr *rta;
+	char *key;
+	char *p;
+	char authenc_name[CRYPTO_MAX_ALG_NAME];
+	unsigned int keylen;
+	int err;
+
+	err = -ENAMETOOLONG;
+
+	if ((x->props.flags & XFRM_STATE_ESN)) {
+		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
+			     "%s%sauthencesn(%s,%s)%s",
+			     x->geniv ?: "", x->geniv ? "(" : "",
+			     x->aalg ? x->aalg->alg_name : "digest_null",
+			     x->ealg->alg_name,
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
+			goto error;
+		}
+	} else {
+		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
+			     "%s%sauthenc(%s,%s)%s",
+			     x->geniv ?: "", x->geniv ? "(" : "",
+			     x->aalg ? x->aalg->alg_name : "digest_null",
+			     x->ealg->alg_name,
+			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
+			NL_SET_ERR_MSG(extack, "Algorithm name is too long");
+			goto error;
+		}
+	}
+
+	aead = crypto_alloc_aead(authenc_name, 0, 0);
+	err = PTR_ERR(aead);
+	if (IS_ERR(aead)) {
+		NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
+		goto error;
+	}
+
+	x->data = aead;
+
+	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
+		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
+	err = -ENOMEM;
+	key = kmalloc(keylen, GFP_KERNEL);
+	if (!key)
+		goto error;
+
+	p = key;
+	rta = (void *)p;
+	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
+	rta->rta_len = RTA_LENGTH(sizeof(*param));
+	param = RTA_DATA(rta);
+	p += RTA_SPACE(sizeof(*param));
+
+	if (x->aalg) {
+		struct xfrm_algo_desc *aalg_desc;
+
+		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
+		p += (x->aalg->alg_key_len + 7) / 8;
+
+		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
+		BUG_ON(!aalg_desc);
+
+		err = -EINVAL;
+		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
+		    crypto_aead_authsize(aead)) {
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
+			goto free_key;
+		}
+
+		err = crypto_aead_setauthsize(aead,
+					      x->aalg->alg_trunc_len / 8);
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
+			goto free_key;
+		}
+	}
+
+	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
+	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
+
+	err = crypto_aead_setkey(aead, key, keylen);
+
+free_key:
+	kfree_sensitive(key);
+
+error:
+	return err;
+}
+EXPORT_SYMBOL_GPL(esp_init_authenc);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Generic ESP");
-- 
2.43.0