net/xfrm/xfrm_input.c - fs/xfs/xfs-linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * xfrm_input.c
  *
  * Changes:
  * 	YOSHIFUJI Hideaki @USAGI
  * 		Split up af-specific portion
  *
  */

 #include <linux/bottom_half.h>
 #include <linux/cache.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/percpu.h>
 #include <net/dst.h>
 #include <net/ip.h>
 #include <net/xfrm.h>
 #include <net/ip_tunnels.h>
 #include <net/ip6_tunnel.h>

 #include "xfrm_inout.h"

 struct xfrm_trans_tasklet {
 	struct tasklet_struct tasklet;
 	struct sk_buff_head queue;
 };

 struct xfrm_trans_cb {
 	union {
 		struct inet_skb_parm	h4;
 #if IS_ENABLED(CONFIG_IPV6)
 		struct inet6_skb_parm	h6;
 #endif
 	} header;
 	int (*finish)(struct net *net, struct sock *sk, struct sk_buff *skb);
 	struct net *net;
 };

 #define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))

 static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
 static struct xfrm_input_afinfo const __rcu *xfrm_input_afinfo[AF_INET6 + 1];

 static struct gro_cells gro_cells;
 static struct net_device xfrm_napi_dev;

 static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);

 int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo)
 {
 	int err = 0;

 	if (WARN_ON(afinfo->family >= ARRAY_SIZE(xfrm_input_afinfo)))
 		return -EAFNOSUPPORT;

 	spin_lock_bh(&xfrm_input_afinfo_lock);
 	if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
 		err = -EEXIST;
 	else
 		rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
 	spin_unlock_bh(&xfrm_input_afinfo_lock);
 	return err;
 }
 EXPORT_SYMBOL(xfrm_input_register_afinfo);

 int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo)
 {
 	int err = 0;

 	spin_lock_bh(&xfrm_input_afinfo_lock);
 	if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
 		if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
 			err = -EINVAL;
 		else
 			RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
 	}
 	spin_unlock_bh(&xfrm_input_afinfo_lock);
 	synchronize_rcu();
 	return err;
 }
 EXPORT_SYMBOL(xfrm_input_unregister_afinfo);

 static const struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
 {
 	const struct xfrm_input_afinfo *afinfo;

 	if (WARN_ON_ONCE(family >= ARRAY_SIZE(xfrm_input_afinfo)))
 		return NULL;

 	rcu_read_lock();
 	afinfo = rcu_dereference(xfrm_input_afinfo[family]);
 	if (unlikely(!afinfo))
 		rcu_read_unlock();
 	return afinfo;
 }

 static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
 		       int err)
 {
 	int ret;
 	const struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);

 	if (!afinfo)
 		return -EAFNOSUPPORT;

 	ret = afinfo->callback(skb, protocol, err);
 	rcu_read_unlock();

 	return ret;
 }

 struct sec_path *secpath_set(struct sk_buff *skb)
 {
 	struct sec_path *sp, *tmp = skb_ext_find(skb, SKB_EXT_SEC_PATH);

 	sp = skb_ext_add(skb, SKB_EXT_SEC_PATH);
 	if (!sp)
 		return NULL;

 	if (tmp) /* reused existing one (was COW'd if needed) */
 		return sp;

 	/* allocated new secpath */
 	memset(sp->ovec, 0, sizeof(sp->ovec));
 	sp->olen = 0;
 	sp->len = 0;

 	return sp;
 }
 EXPORT_SYMBOL(secpath_set);

 /* Fetch spi and seq from ipsec header */

 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 {
 	int offset, offset_seq;
 	int hlen;

 	switch (nexthdr) {
 	case IPPROTO_AH:
 		hlen = sizeof(struct ip_auth_hdr);
 		offset = offsetof(struct ip_auth_hdr, spi);
 		offset_seq = offsetof(struct ip_auth_hdr, seq_no);
 		break;
 	case IPPROTO_ESP:
 		hlen = sizeof(struct ip_esp_hdr);
 		offset = offsetof(struct ip_esp_hdr, spi);
 		offset_seq = offsetof(struct ip_esp_hdr, seq_no);
 		break;
 	case IPPROTO_COMP:
 		if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
 			return -EINVAL;
 		*spi = htonl(ntohs(*(__be16 *)(skb_transport_header(skb) + 2)));
 		*seq = 0;
 		return 0;
 	default:
 		return 1;
 	}

 	if (!pskb_may_pull(skb, hlen))
 		return -EINVAL;

 	*spi = *(__be32 *)(skb_transport_header(skb) + offset);
 	*seq = *(__be32 *)(skb_transport_header(skb) + offset_seq);
 	return 0;
 }
 EXPORT_SYMBOL(xfrm_parse_spi);

 static int xfrm4_remove_beet_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct iphdr *iph;
 	int optlen = 0;
 	int err = -EINVAL;

 	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
 		struct ip_beet_phdr *ph;
 		int phlen;

 		if (!pskb_may_pull(skb, sizeof(*ph)))
 			goto out;

 		ph = (struct ip_beet_phdr *)skb->data;

 		phlen = sizeof(*ph) + ph->padlen;
 		optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
 		if (optlen < 0 || optlen & 3 || optlen > 250)
 			goto out;

 		XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;

 		if (!pskb_may_pull(skb, phlen))
 			goto out;
 		__skb_pull(skb, phlen);
 	}

 	skb_push(skb, sizeof(*iph));
 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);

 	xfrm4_beet_make_header(skb);

 	iph = ip_hdr(skb);

 	iph->ihl += optlen / 4;
 	iph->tot_len = htons(skb->len);
 	iph->daddr = x->sel.daddr.a4;
 	iph->saddr = x->sel.saddr.a4;
 	iph->check = 0;
 	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
 	err = 0;
 out:
 	return err;
 }

 static void ipip_ecn_decapsulate(struct sk_buff *skb)
 {
 	struct iphdr *inner_iph = ipip_hdr(skb);

 	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
 		IP_ECN_set_ce(inner_iph);
 }

 static int xfrm4_remove_tunnel_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -EINVAL;

 	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
 		goto out;

 	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 		goto out;

 	err = skb_unclone(skb, GFP_ATOMIC);
 	if (err)
 		goto out;

 	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
 		ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
 	if (!(x->props.flags & XFRM_STATE_NOECN))
 		ipip_ecn_decapsulate(skb);

 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);
 	if (skb->mac_len)
 		eth_hdr(skb)->h_proto = skb->protocol;

 	err = 0;

 out:
 	return err;
 }

 static void ipip6_ecn_decapsulate(struct sk_buff *skb)
 {
 	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);

 	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
 		IP6_ECN_set_ce(skb, inner_iph);
 }

 static int xfrm6_remove_tunnel_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -EINVAL;

 	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
 		goto out;
 	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 		goto out;

 	err = skb_unclone(skb, GFP_ATOMIC);
 	if (err)
 		goto out;

 	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
 		ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
 			       ipipv6_hdr(skb));
 	if (!(x->props.flags & XFRM_STATE_NOECN))
 		ipip6_ecn_decapsulate(skb);

 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);
 	if (skb->mac_len)
 		eth_hdr(skb)->h_proto = skb->protocol;

 	err = 0;

 out:
 	return err;
 }

 static int xfrm6_remove_beet_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct ipv6hdr *ip6h;
 	int size = sizeof(struct ipv6hdr);
 	int err;

 	err = skb_cow_head(skb, size + skb->mac_len);
 	if (err)
 		goto out;

 	__skb_push(skb, size);
 	skb_reset_network_header(skb);
 	skb_mac_header_rebuild(skb);

 	xfrm6_beet_make_header(skb);

 	ip6h = ipv6_hdr(skb);
 	ip6h->payload_len = htons(skb->len - size);
 	ip6h->daddr = x->sel.daddr.in6;
 	ip6h->saddr = x->sel.saddr.in6;
 	err = 0;
 out:
 	return err;
 }

 /* Remove encapsulation header.
  *
  * The IP header will be moved over the top of the encapsulation
  * header.
  *
  * On entry, the transport header shall point to where the IP header
  * should be and the network header shall be set to where the IP
  * header currently is.  skb->data shall point to the start of the
  * payload.
  */
 static int
 xfrm_inner_mode_encap_remove(struct xfrm_state *x,
 			     const struct xfrm_mode *inner_mode,
 			     struct sk_buff *skb)
 {
 	switch (inner_mode->encap) {
 	case XFRM_MODE_BEET:
 		if (inner_mode->family == AF_INET)
 			return xfrm4_remove_beet_encap(x, skb);
 		if (inner_mode->family == AF_INET6)
 			return xfrm6_remove_beet_encap(x, skb);
 		break;
 	case XFRM_MODE_TUNNEL:
 		if (inner_mode->family == AF_INET)
 			return xfrm4_remove_tunnel_encap(x, skb);
 		if (inner_mode->family == AF_INET6)
 			return xfrm6_remove_tunnel_encap(x, skb);
 		break;
 	}

 	WARN_ON_ONCE(1);
 	return -EOPNOTSUPP;
 }

 static int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 	const struct xfrm_mode *inner_mode = &x->inner_mode;
 	const struct xfrm_state_afinfo *afinfo;
 	int err = -EAFNOSUPPORT;

 	rcu_read_lock();
 	afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
 	if (likely(afinfo))
 		err = afinfo->extract_input(x, skb);
 	rcu_read_unlock();

 	if (err)
 		return err;

 	if (x->sel.family == AF_UNSPEC) {
 		inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 		if (!inner_mode)
 			return -EAFNOSUPPORT;
 	}

 	switch (inner_mode->family) {
 	case AF_INET:
 		skb->protocol = htons(ETH_P_IP);
 		break;
 	case AF_INET6:
 		skb->protocol = htons(ETH_P_IPV6);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		break;
 	}

 	return xfrm_inner_mode_encap_remove(x, inner_mode, skb);
 }

 /* Remove encapsulation header.
  *
  * The IP header will be moved over the top of the encapsulation header.
  *
  * On entry, skb_transport_header() shall point to where the IP header
  * should be and skb_network_header() shall be set to where the IP header
  * currently is.  skb->data shall point to the start of the payload.
  */
 static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int ihl = skb->data - skb_transport_header(skb);

 	if (skb->transport_header != skb->network_header) {
 		memmove(skb_transport_header(skb),
 			skb_network_header(skb), ihl);
 		skb->network_header = skb->transport_header;
 	}
 	ip_hdr(skb)->tot_len = htons(skb->len + ihl);
 	skb_reset_transport_header(skb);
 	return 0;
 }

 static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 #if IS_ENABLED(CONFIG_IPV6)
 	int ihl = skb->data - skb_transport_header(skb);

 	if (skb->transport_header != skb->network_header) {
 		memmove(skb_transport_header(skb),
 			skb_network_header(skb), ihl);
 		skb->network_header = skb->transport_header;
 	}
 	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
 					   sizeof(struct ipv6hdr));
 	skb_reset_transport_header(skb);
 	return 0;
 #else
 	WARN_ON_ONCE(1);
 	return -EAFNOSUPPORT;
 #endif
 }

 static int xfrm_inner_mode_input(struct xfrm_state *x,
 				 const struct xfrm_mode *inner_mode,
 				 struct sk_buff *skb)
 {
 	switch (inner_mode->encap) {
 	case XFRM_MODE_BEET:
 	case XFRM_MODE_TUNNEL:
 		return xfrm_prepare_input(x, skb);
 	case XFRM_MODE_TRANSPORT:
 		if (inner_mode->family == AF_INET)
 			return xfrm4_transport_input(x, skb);
 		if (inner_mode->family == AF_INET6)
 			return xfrm6_transport_input(x, skb);
 		break;
 	case XFRM_MODE_ROUTEOPTIMIZATION:
 		WARN_ON_ONCE(1);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		break;
 	}

 	return -EOPNOTSUPP;
 }

 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 {
 	const struct xfrm_state_afinfo *afinfo;
 	struct net *net = dev_net(skb->dev);
 	const struct xfrm_mode *inner_mode;
 	int err;
 	__be32 seq;
 	__be32 seq_hi;
 	struct xfrm_state *x = NULL;
 	xfrm_address_t *daddr;
 	u32 mark = skb->mark;
 	unsigned int family = AF_UNSPEC;
 	int decaps = 0;
 	int async = 0;
 	bool xfrm_gro = false;
 	bool crypto_done = false;
 	struct xfrm_offload *xo = xfrm_offload(skb);
 	struct sec_path *sp;

 	if (encap_type < 0) {
 		x = xfrm_input_state(skb);

 		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 			if (x->km.state == XFRM_STATE_ACQ)
 				XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
 			else
 				XFRM_INC_STATS(net,
 					       LINUX_MIB_XFRMINSTATEINVALID);

 			if (encap_type == -1)
 				dev_put(skb->dev);
 			goto drop;
 		}

 		family = x->outer_mode.family;

 		/* An encap_type of -1 indicates async resumption. */
 		if (encap_type == -1) {
 			async = 1;
 			seq = XFRM_SKB_CB(skb)->seq.input.low;
 			goto resume;
 		}

 		/* encap_type < -1 indicates a GRO call. */
 		encap_type = 0;
 		seq = XFRM_SPI_SKB_CB(skb)->seq;

 		if (xo && (xo->flags & CRYPTO_DONE)) {
 			crypto_done = true;
 			family = XFRM_SPI_SKB_CB(skb)->family;

 			if (!(xo->status & CRYPTO_SUCCESS)) {
 				if (xo->status &
 				    (CRYPTO_TRANSPORT_AH_AUTH_FAILED |
 				     CRYPTO_TRANSPORT_ESP_AUTH_FAILED |
 				     CRYPTO_TUNNEL_AH_AUTH_FAILED |
 				     CRYPTO_TUNNEL_ESP_AUTH_FAILED)) {

 					xfrm_audit_state_icvfail(x, skb,
 								 x->type->proto);
 					x->stats.integrity_failed++;
 					XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 					goto drop;
 				}

 				if (xo->status & CRYPTO_INVALID_PROTOCOL) {
 					XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 					goto drop;
 				}

 				XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 				goto drop;
 			}

 			if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 				XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 				goto drop;
 			}
 		}

 		goto lock;
 	}

 	family = XFRM_SPI_SKB_CB(skb)->family;

 	/* if tunnel is present override skb->mark value with tunnel i_key */
 	switch (family) {
 	case AF_INET:
 		if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)
 			mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);
 		break;
 	case AF_INET6:
 		if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)
 			mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);
 		break;
 	}

 	sp = secpath_set(skb);
 	if (!sp) {
 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 		goto drop;
 	}

 	seq = 0;
 	if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
 		secpath_reset(skb);
 		XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 		goto drop;
 	}

 	daddr = (xfrm_address_t *)(skb_network_header(skb) +
 				   XFRM_SPI_SKB_CB(skb)->daddroff);
 	do {
 		sp = skb_sec_path(skb);

 		if (sp->len == XFRM_MAX_DEPTH) {
 			secpath_reset(skb);
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
 			goto drop;
 		}

 		x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);
 		if (x == NULL) {
 			secpath_reset(skb);
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
 			xfrm_audit_state_notfound(skb, family, spi, seq);
 			goto drop;
 		}

 		skb->mark = xfrm_smark_get(skb->mark, x);

 		sp->xvec[sp->len++] = x;

 		skb_dst_force(skb);
 		if (!skb_dst(skb)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
 			goto drop;
 		}

 lock:
 		spin_lock(&x->lock);

 		if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 			if (x->km.state == XFRM_STATE_ACQ)
 				XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
 			else
 				XFRM_INC_STATS(net,
 					       LINUX_MIB_XFRMINSTATEINVALID);
 			goto drop_unlock;
 		}

 		if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
 			goto drop_unlock;
 		}

 		if (x->repl->check(x, skb, seq)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 			goto drop_unlock;
 		}

 		if (xfrm_state_check_expire(x)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
 			goto drop_unlock;
 		}

 		spin_unlock(&x->lock);

 		if (xfrm_tunnel_check(skb, x, family)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 			goto drop;
 		}

 		seq_hi = htonl(xfrm_replay_seqhi(x, seq));

 		XFRM_SKB_CB(skb)->seq.input.low = seq;
 		XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;

 		dev_hold(skb->dev);

 		if (crypto_done)
 			nexthdr = x->type_offload->input_tail(x, skb);
 		else
 			nexthdr = x->type->input(x, skb);

 		if (nexthdr == -EINPROGRESS)
 			return 0;
 resume:
 		dev_put(skb->dev);

 		spin_lock(&x->lock);
 		if (nexthdr <= 0) {
 			if (nexthdr == -EBADMSG) {
 				xfrm_audit_state_icvfail(x, skb,
 							 x->type->proto);
 				x->stats.integrity_failed++;
 			}
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
 			goto drop_unlock;
 		}

 		/* only the first xfrm gets the encap type */
 		encap_type = 0;

 		if (async && x->repl->recheck(x, skb, seq)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
 			goto drop_unlock;
 		}

 		x->repl->advance(x, seq);

 		x->curlft.bytes += skb->len;
 		x->curlft.packets++;

 		spin_unlock(&x->lock);

 		XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;

 		inner_mode = &x->inner_mode;

 		if (x->sel.family == AF_UNSPEC) {
 			inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 			if (inner_mode == NULL) {
 				XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 				goto drop;
 			}
 		}

 		if (xfrm_inner_mode_input(x, inner_mode, skb)) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
 			goto drop;
 		}

 		if (x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL) {
 			decaps = 1;
 			break;
 		}

 		/*
 		 * We need the inner address.  However, we only get here for
 		 * transport mode so the outer address is identical.
 		 */
 		daddr = &x->id.daddr;
 		family = x->outer_mode.family;

 		err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 		if (err < 0) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
 			goto drop;
 		}
 		crypto_done = false;
 	} while (!err);

 	err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
 	if (err)
 		goto drop;

 	nf_reset_ct(skb);

 	if (decaps) {
 		sp = skb_sec_path(skb);
 		if (sp)
 			sp->olen = 0;
 		skb_dst_drop(skb);
 		gro_cells_receive(&gro_cells, skb);
 		return 0;
 	} else {
 		xo = xfrm_offload(skb);
 		if (xo)
 			xfrm_gro = xo->flags & XFRM_GRO;

 		err = -EAFNOSUPPORT;
 		rcu_read_lock();
 		afinfo = xfrm_state_afinfo_get_rcu(x->inner_mode.family);
 		if (likely(afinfo))
 			err = afinfo->transport_finish(skb, xfrm_gro || async);
 		rcu_read_unlock();
 		if (xfrm_gro) {
 			sp = skb_sec_path(skb);
 			if (sp)
 				sp->olen = 0;
 			skb_dst_drop(skb);
 			gro_cells_receive(&gro_cells, skb);
 			return err;
 		}

 		return err;
 	}

 drop_unlock:
 	spin_unlock(&x->lock);
 drop:
 	xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
 	kfree_skb(skb);
 	return 0;
 }
 EXPORT_SYMBOL(xfrm_input);

 int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
 {
 	return xfrm_input(skb, nexthdr, 0, -1);
 }
 EXPORT_SYMBOL(xfrm_input_resume);

 static void xfrm_trans_reinject(unsigned long data)
 {
 	struct xfrm_trans_tasklet *trans = (void *)data;
 	struct sk_buff_head queue;
 	struct sk_buff *skb;

 	__skb_queue_head_init(&queue);
 	skb_queue_splice_init(&trans->queue, &queue);

 	while ((skb = __skb_dequeue(&queue)))
 		XFRM_TRANS_SKB_CB(skb)->finish(XFRM_TRANS_SKB_CB(skb)->net,
 					       NULL, skb);
 }

 int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb,
 			 int (*finish)(struct net *, struct sock *,
 				       struct sk_buff *))
 {
 	struct xfrm_trans_tasklet *trans;

 	trans = this_cpu_ptr(&xfrm_trans_tasklet);

 	if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
 		return -ENOBUFS;

 	BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));

 	XFRM_TRANS_SKB_CB(skb)->finish = finish;
 	XFRM_TRANS_SKB_CB(skb)->net = net;
 	__skb_queue_tail(&trans->queue, skb);
 	tasklet_schedule(&trans->tasklet);
 	return 0;
 }
 EXPORT_SYMBOL(xfrm_trans_queue_net);

 int xfrm_trans_queue(struct sk_buff *skb,
 		     int (*finish)(struct net *, struct sock *,
 				   struct sk_buff *))
 {
 	return xfrm_trans_queue_net(dev_net(skb->dev), skb, finish);
 }
 EXPORT_SYMBOL(xfrm_trans_queue);

 void __init xfrm_input_init(void)
 {
 	int err;
 	int i;

 	init_dummy_netdev(&xfrm_napi_dev);
 	err = gro_cells_init(&gro_cells, &xfrm_napi_dev);
 	if (err)
 		gro_cells.cells = NULL;

 	for_each_possible_cpu(i) {
 		struct xfrm_trans_tasklet *trans;

 		trans = &per_cpu(xfrm_trans_tasklet, i);
 		__skb_queue_head_init(&trans->queue);
 		tasklet_init(&trans->tasklet, xfrm_trans_reinject,
 			     (unsigned long)trans);
 	}
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* xfrm_input.c
	*
	* Changes:
	* YOSHIFUJI Hideaki @USAGI
	* Split up af-specific portion
	*
	*/

	#include <linux/bottom_half.h>
	#include <linux/cache.h>
	#include <linux/interrupt.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/netdevice.h>
	#include <linux/percpu.h>
	#include <net/dst.h>
	#include <net/ip.h>
	#include <net/xfrm.h>
	#include <net/ip_tunnels.h>
	#include <net/ip6_tunnel.h>

	#include "xfrm_inout.h"

	struct xfrm_trans_tasklet {
	struct tasklet_struct tasklet;
	struct sk_buff_head queue;
	};

	struct xfrm_trans_cb {
	union {
	struct inet_skb_parm h4;
	#if IS_ENABLED(CONFIG_IPV6)
	struct inet6_skb_parm h6;
	#endif
	} header;
	int (finish)(struct net net, struct sock sk, struct sk_buff skb);
	struct net *net;
	};

	#define XFRM_TRANS_SKB_CB(__skb) ((struct xfrm_trans_cb *)&((__skb)->cb[0]))

	static DEFINE_SPINLOCK(xfrm_input_afinfo_lock);
	static struct xfrm_input_afinfo const __rcu *xfrm_input_afinfo[AF_INET6 + 1];

	static struct gro_cells gro_cells;
	static struct net_device xfrm_napi_dev;

	static DEFINE_PER_CPU(struct xfrm_trans_tasklet, xfrm_trans_tasklet);

	int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo)
	{
	int err = 0;

	if (WARN_ON(afinfo->family >= ARRAY_SIZE(xfrm_input_afinfo)))
	return -EAFNOSUPPORT;

	spin_lock_bh(&xfrm_input_afinfo_lock);
	if (unlikely(xfrm_input_afinfo[afinfo->family] != NULL))
	err = -EEXIST;
	else
	rcu_assign_pointer(xfrm_input_afinfo[afinfo->family], afinfo);
	spin_unlock_bh(&xfrm_input_afinfo_lock);
	return err;
	}
	EXPORT_SYMBOL(xfrm_input_register_afinfo);

	int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo)
	{
	int err = 0;

	spin_lock_bh(&xfrm_input_afinfo_lock);
	if (likely(xfrm_input_afinfo[afinfo->family] != NULL)) {
	if (unlikely(xfrm_input_afinfo[afinfo->family] != afinfo))
	err = -EINVAL;
	else
	RCU_INIT_POINTER(xfrm_input_afinfo[afinfo->family], NULL);
	}
	spin_unlock_bh(&xfrm_input_afinfo_lock);
	synchronize_rcu();
	return err;
	}
	EXPORT_SYMBOL(xfrm_input_unregister_afinfo);

	static const struct xfrm_input_afinfo *xfrm_input_get_afinfo(unsigned int family)
	{
	const struct xfrm_input_afinfo *afinfo;

	if (WARN_ON_ONCE(family >= ARRAY_SIZE(xfrm_input_afinfo)))
	return NULL;

	rcu_read_lock();
	afinfo = rcu_dereference(xfrm_input_afinfo[family]);
	if (unlikely(!afinfo))
	rcu_read_unlock();
	return afinfo;
	}

	static int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family, u8 protocol,
	int err)
	{
	int ret;
	const struct xfrm_input_afinfo *afinfo = xfrm_input_get_afinfo(family);

	if (!afinfo)
	return -EAFNOSUPPORT;

	ret = afinfo->callback(skb, protocol, err);
	rcu_read_unlock();

	return ret;
	}

	struct sec_path secpath_set(struct sk_buff skb)
	{
	struct sec_path sp, tmp = skb_ext_find(skb, SKB_EXT_SEC_PATH);

	sp = skb_ext_add(skb, SKB_EXT_SEC_PATH);
	if (!sp)
	return NULL;

	if (tmp) /* reused existing one (was COW'd if needed) */
	return sp;

	/* allocated new secpath */
	memset(sp->ovec, 0, sizeof(sp->ovec));
	sp->olen = 0;
	sp->len = 0;

	return sp;
	}
	EXPORT_SYMBOL(secpath_set);

	/* Fetch spi and seq from ipsec header */

	int xfrm_parse_spi(struct sk_buff skb, u8 nexthdr, __be32 spi, __be32 *seq)
	{
	int offset, offset_seq;
	int hlen;

	switch (nexthdr) {
	case IPPROTO_AH:
	hlen = sizeof(struct ip_auth_hdr);
	offset = offsetof(struct ip_auth_hdr, spi);
	offset_seq = offsetof(struct ip_auth_hdr, seq_no);
	break;
	case IPPROTO_ESP:
	hlen = sizeof(struct ip_esp_hdr);
	offset = offsetof(struct ip_esp_hdr, spi);
	offset_seq = offsetof(struct ip_esp_hdr, seq_no);
	break;
	case IPPROTO_COMP:
	if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
	return -EINVAL;
	spi = htonl(ntohs((__be16 *)(skb_transport_header(skb) + 2)));
	*seq = 0;
	return 0;
	default:
	return 1;
	}

	if (!pskb_may_pull(skb, hlen))
	return -EINVAL;

	spi = (__be32 *)(skb_transport_header(skb) + offset);
	seq = (__be32 *)(skb_transport_header(skb) + offset_seq);
	return 0;
	}
	EXPORT_SYMBOL(xfrm_parse_spi);

	static int xfrm4_remove_beet_encap(struct xfrm_state x, struct sk_buff skb)
	{
	struct iphdr *iph;
	int optlen = 0;
	int err = -EINVAL;

	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
	struct ip_beet_phdr *ph;
	int phlen;

	if (!pskb_may_pull(skb, sizeof(*ph)))
	goto out;

	ph = (struct ip_beet_phdr *)skb->data;

	phlen = sizeof(*ph) + ph->padlen;
	optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
	if (optlen < 0 \|\| optlen & 3 \|\| optlen > 250)
	goto out;

	XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;

	if (!pskb_may_pull(skb, phlen))
	goto out;
	__skb_pull(skb, phlen);
	}

	skb_push(skb, sizeof(*iph));
	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);

	xfrm4_beet_make_header(skb);

	iph = ip_hdr(skb);

	iph->ihl += optlen / 4;
	iph->tot_len = htons(skb->len);
	iph->daddr = x->sel.daddr.a4;
	iph->saddr = x->sel.saddr.a4;
	iph->check = 0;
	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
	err = 0;
	out:
	return err;
	}

	static void ipip_ecn_decapsulate(struct sk_buff *skb)
	{
	struct iphdr *inner_iph = ipip_hdr(skb);

	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
	IP_ECN_set_ce(inner_iph);
	}

	static int xfrm4_remove_tunnel_encap(struct xfrm_state x, struct sk_buff skb)
	{
	int err = -EINVAL;

	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
	goto out;

	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	goto out;

	err = skb_unclone(skb, GFP_ATOMIC);
	if (err)
	goto out;

	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
	if (!(x->props.flags & XFRM_STATE_NOECN))
	ipip_ecn_decapsulate(skb);

	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);
	if (skb->mac_len)
	eth_hdr(skb)->h_proto = skb->protocol;

	err = 0;

	out:
	return err;
	}

	static void ipip6_ecn_decapsulate(struct sk_buff *skb)
	{
	struct ipv6hdr *inner_iph = ipipv6_hdr(skb);

	if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
	IP6_ECN_set_ce(skb, inner_iph);
	}

	static int xfrm6_remove_tunnel_encap(struct xfrm_state x, struct sk_buff skb)
	{
	int err = -EINVAL;

	if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
	goto out;
	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
	goto out;

	err = skb_unclone(skb, GFP_ATOMIC);
	if (err)
	goto out;

	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
	ipipv6_hdr(skb));
	if (!(x->props.flags & XFRM_STATE_NOECN))
	ipip6_ecn_decapsulate(skb);

	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);
	if (skb->mac_len)
	eth_hdr(skb)->h_proto = skb->protocol;

	err = 0;

	out:
	return err;
	}

	static int xfrm6_remove_beet_encap(struct xfrm_state x, struct sk_buff skb)
	{
	struct ipv6hdr *ip6h;
	int size = sizeof(struct ipv6hdr);
	int err;

	err = skb_cow_head(skb, size + skb->mac_len);
	if (err)
	goto out;

	__skb_push(skb, size);
	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);

	xfrm6_beet_make_header(skb);

	ip6h = ipv6_hdr(skb);
	ip6h->payload_len = htons(skb->len - size);
	ip6h->daddr = x->sel.daddr.in6;
	ip6h->saddr = x->sel.saddr.in6;
	err = 0;
	out:
	return err;
	}

	/* Remove encapsulation header.
	*
	* The IP header will be moved over the top of the encapsulation
	* header.
	*
	* On entry, the transport header shall point to where the IP header
	* should be and the network header shall be set to where the IP
	* header currently is. skb->data shall point to the start of the
	* payload.
	*/
	static int
	xfrm_inner_mode_encap_remove(struct xfrm_state *x,
	const struct xfrm_mode *inner_mode,
	struct sk_buff *skb)
	{
	switch (inner_mode->encap) {
	case XFRM_MODE_BEET:
	if (inner_mode->family == AF_INET)
	return xfrm4_remove_beet_encap(x, skb);
	if (inner_mode->family == AF_INET6)
	return xfrm6_remove_beet_encap(x, skb);
	break;
	case XFRM_MODE_TUNNEL:
	if (inner_mode->family == AF_INET)
	return xfrm4_remove_tunnel_encap(x, skb);
	if (inner_mode->family == AF_INET6)
	return xfrm6_remove_tunnel_encap(x, skb);
	break;
	}

	WARN_ON_ONCE(1);
	return -EOPNOTSUPP;
	}

	static int xfrm_prepare_input(struct xfrm_state x, struct sk_buff skb)
	{
	const struct xfrm_mode *inner_mode = &x->inner_mode;
	const struct xfrm_state_afinfo *afinfo;
	int err = -EAFNOSUPPORT;

	rcu_read_lock();
	afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
	if (likely(afinfo))
	err = afinfo->extract_input(x, skb);
	rcu_read_unlock();

	if (err)
	return err;

	if (x->sel.family == AF_UNSPEC) {
	inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
	if (!inner_mode)
	return -EAFNOSUPPORT;
	}

	switch (inner_mode->family) {
	case AF_INET:
	skb->protocol = htons(ETH_P_IP);
	break;
	case AF_INET6:
	skb->protocol = htons(ETH_P_IPV6);
	break;
	default:
	WARN_ON_ONCE(1);
	break;
	}

	return xfrm_inner_mode_encap_remove(x, inner_mode, skb);
	}

	/* Remove encapsulation header.
	*
	* The IP header will be moved over the top of the encapsulation header.
	*
	* On entry, skb_transport_header() shall point to where the IP header
	* should be and skb_network_header() shall be set to where the IP header
	* currently is. skb->data shall point to the start of the payload.
	*/
	static int xfrm4_transport_input(struct xfrm_state x, struct sk_buff skb)
	{
	int ihl = skb->data - skb_transport_header(skb);

	if (skb->transport_header != skb->network_header) {
	memmove(skb_transport_header(skb),
	skb_network_header(skb), ihl);
	skb->network_header = skb->transport_header;
	}
	ip_hdr(skb)->tot_len = htons(skb->len + ihl);
	skb_reset_transport_header(skb);
	return 0;
	}

	static int xfrm6_transport_input(struct xfrm_state x, struct sk_buff skb)
	{
	#if IS_ENABLED(CONFIG_IPV6)
	int ihl = skb->data - skb_transport_header(skb);

	if (skb->transport_header != skb->network_header) {
	memmove(skb_transport_header(skb),
	skb_network_header(skb), ihl);
	skb->network_header = skb->transport_header;
	}
	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
	sizeof(struct ipv6hdr));
	skb_reset_transport_header(skb);
	return 0;
	#else
	WARN_ON_ONCE(1);
	return -EAFNOSUPPORT;
	#endif
	}

	static int xfrm_inner_mode_input(struct xfrm_state *x,
	const struct xfrm_mode *inner_mode,
	struct sk_buff *skb)
	{
	switch (inner_mode->encap) {
	case XFRM_MODE_BEET:
	case XFRM_MODE_TUNNEL:
	return xfrm_prepare_input(x, skb);
	case XFRM_MODE_TRANSPORT:
	if (inner_mode->family == AF_INET)
	return xfrm4_transport_input(x, skb);
	if (inner_mode->family == AF_INET6)
	return xfrm6_transport_input(x, skb);
	break;
	case XFRM_MODE_ROUTEOPTIMIZATION:
	WARN_ON_ONCE(1);
	break;
	default:
	WARN_ON_ONCE(1);
	break;
	}

	return -EOPNOTSUPP;
	}

	int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
	{
	const struct xfrm_state_afinfo *afinfo;
	struct net *net = dev_net(skb->dev);
	const struct xfrm_mode *inner_mode;
	int err;
	__be32 seq;
	__be32 seq_hi;
	struct xfrm_state *x = NULL;
	xfrm_address_t *daddr;
	u32 mark = skb->mark;
	unsigned int family = AF_UNSPEC;
	int decaps = 0;
	int async = 0;
	bool xfrm_gro = false;
	bool crypto_done = false;
	struct xfrm_offload *xo = xfrm_offload(skb);
	struct sec_path *sp;

	if (encap_type < 0) {
	x = xfrm_input_state(skb);

	if (unlikely(x->km.state != XFRM_STATE_VALID)) {
	if (x->km.state == XFRM_STATE_ACQ)
	XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
	else
	XFRM_INC_STATS(net,
	LINUX_MIB_XFRMINSTATEINVALID);

	if (encap_type == -1)
	dev_put(skb->dev);
	goto drop;
	}

	family = x->outer_mode.family;

	/* An encap_type of -1 indicates async resumption. */
	if (encap_type == -1) {
	async = 1;
	seq = XFRM_SKB_CB(skb)->seq.input.low;
	goto resume;
	}

	/* encap_type < -1 indicates a GRO call. */
	encap_type = 0;
	seq = XFRM_SPI_SKB_CB(skb)->seq;

	if (xo && (xo->flags & CRYPTO_DONE)) {
	crypto_done = true;
	family = XFRM_SPI_SKB_CB(skb)->family;

	if (!(xo->status & CRYPTO_SUCCESS)) {
	if (xo->status &
	(CRYPTO_TRANSPORT_AH_AUTH_FAILED \|
	CRYPTO_TRANSPORT_ESP_AUTH_FAILED \|
	CRYPTO_TUNNEL_AH_AUTH_FAILED \|
	CRYPTO_TUNNEL_ESP_AUTH_FAILED)) {

	xfrm_audit_state_icvfail(x, skb,
	x->type->proto);
	x->stats.integrity_failed++;
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
	goto drop;
	}

	if (xo->status & CRYPTO_INVALID_PROTOCOL) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
	goto drop;
	}

	XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
	goto drop;
	}

	if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
	goto drop;
	}
	}

	goto lock;
	}

	family = XFRM_SPI_SKB_CB(skb)->family;

	/* if tunnel is present override skb->mark value with tunnel i_key */
	switch (family) {
	case AF_INET:
	if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)
	mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4->parms.i_key);
	break;
	case AF_INET6:
	if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)
	mark = be32_to_cpu(XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6->parms.i_key);
	break;
	}

	sp = secpath_set(skb);
	if (!sp) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
	goto drop;
	}

	seq = 0;
	if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0) {
	secpath_reset(skb);
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
	goto drop;
	}

	daddr = (xfrm_address_t *)(skb_network_header(skb) +
	XFRM_SPI_SKB_CB(skb)->daddroff);
	do {
	sp = skb_sec_path(skb);

	if (sp->len == XFRM_MAX_DEPTH) {
	secpath_reset(skb);
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
	goto drop;
	}

	x = xfrm_state_lookup(net, mark, daddr, spi, nexthdr, family);
	if (x == NULL) {
	secpath_reset(skb);
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
	xfrm_audit_state_notfound(skb, family, spi, seq);
	goto drop;
	}

	skb->mark = xfrm_smark_get(skb->mark, x);

	sp->xvec[sp->len++] = x;

	skb_dst_force(skb);
	if (!skb_dst(skb)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
	goto drop;
	}

	lock:
	spin_lock(&x->lock);

	if (unlikely(x->km.state != XFRM_STATE_VALID)) {
	if (x->km.state == XFRM_STATE_ACQ)
	XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);
	else
	XFRM_INC_STATS(net,
	LINUX_MIB_XFRMINSTATEINVALID);
	goto drop_unlock;
	}

	if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMISMATCH);
	goto drop_unlock;
	}

	if (x->repl->check(x, skb, seq)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
	goto drop_unlock;
	}

	if (xfrm_state_check_expire(x)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEEXPIRED);
	goto drop_unlock;
	}

	spin_unlock(&x->lock);

	if (xfrm_tunnel_check(skb, x, family)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
	goto drop;
	}

	seq_hi = htonl(xfrm_replay_seqhi(x, seq));

	XFRM_SKB_CB(skb)->seq.input.low = seq;
	XFRM_SKB_CB(skb)->seq.input.hi = seq_hi;

	dev_hold(skb->dev);

	if (crypto_done)
	nexthdr = x->type_offload->input_tail(x, skb);
	else
	nexthdr = x->type->input(x, skb);

	if (nexthdr == -EINPROGRESS)
	return 0;
	resume:
	dev_put(skb->dev);

	spin_lock(&x->lock);
	if (nexthdr <= 0) {
	if (nexthdr == -EBADMSG) {
	xfrm_audit_state_icvfail(x, skb,
	x->type->proto);
	x->stats.integrity_failed++;
	}
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEPROTOERROR);
	goto drop_unlock;
	}

	/* only the first xfrm gets the encap type */
	encap_type = 0;

	if (async && x->repl->recheck(x, skb, seq)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATESEQERROR);
	goto drop_unlock;
	}

	x->repl->advance(x, seq);

	x->curlft.bytes += skb->len;
	x->curlft.packets++;

	spin_unlock(&x->lock);

	XFRM_MODE_SKB_CB(skb)->protocol = nexthdr;

	inner_mode = &x->inner_mode;

	if (x->sel.family == AF_UNSPEC) {
	inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
	if (inner_mode == NULL) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
	goto drop;
	}
	}

	if (xfrm_inner_mode_input(x, inner_mode, skb)) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
	goto drop;
	}

	if (x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL) {
	decaps = 1;
	break;
	}

	/*
	* We need the inner address. However, we only get here for
	* transport mode so the outer address is identical.
	*/
	daddr = &x->id.daddr;
	family = x->outer_mode.family;

	err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
	if (err < 0) {
	XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
	goto drop;
	}
	crypto_done = false;
	} while (!err);

	err = xfrm_rcv_cb(skb, family, x->type->proto, 0);
	if (err)
	goto drop;

	nf_reset_ct(skb);

	if (decaps) {
	sp = skb_sec_path(skb);
	if (sp)
	sp->olen = 0;
	skb_dst_drop(skb);
	gro_cells_receive(&gro_cells, skb);
	return 0;
	} else {
	xo = xfrm_offload(skb);
	if (xo)
	xfrm_gro = xo->flags & XFRM_GRO;

	err = -EAFNOSUPPORT;
	rcu_read_lock();
	afinfo = xfrm_state_afinfo_get_rcu(x->inner_mode.family);
	if (likely(afinfo))
	err = afinfo->transport_finish(skb, xfrm_gro \|\| async);
	rcu_read_unlock();
	if (xfrm_gro) {
	sp = skb_sec_path(skb);
	if (sp)
	sp->olen = 0;
	skb_dst_drop(skb);
	gro_cells_receive(&gro_cells, skb);
	return err;
	}

	return err;
	}

	drop_unlock:
	spin_unlock(&x->lock);
	drop:
	xfrm_rcv_cb(skb, family, x && x->type ? x->type->proto : nexthdr, -1);
	kfree_skb(skb);
	return 0;
	}
	EXPORT_SYMBOL(xfrm_input);

	int xfrm_input_resume(struct sk_buff *skb, int nexthdr)
	{
	return xfrm_input(skb, nexthdr, 0, -1);
	}
	EXPORT_SYMBOL(xfrm_input_resume);

	static void xfrm_trans_reinject(unsigned long data)
	{
	struct xfrm_trans_tasklet trans = (void )data;
	struct sk_buff_head queue;
	struct sk_buff *skb;

	__skb_queue_head_init(&queue);
	skb_queue_splice_init(&trans->queue, &queue);

	while ((skb = __skb_dequeue(&queue)))
	XFRM_TRANS_SKB_CB(skb)->finish(XFRM_TRANS_SKB_CB(skb)->net,
	NULL, skb);
	}

	int xfrm_trans_queue_net(struct net net, struct sk_buff skb,
	int (finish)(struct net , struct sock *,
	struct sk_buff *))
	{
	struct xfrm_trans_tasklet *trans;

	trans = this_cpu_ptr(&xfrm_trans_tasklet);

	if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
	return -ENOBUFS;

	BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));

	XFRM_TRANS_SKB_CB(skb)->finish = finish;
	XFRM_TRANS_SKB_CB(skb)->net = net;
	__skb_queue_tail(&trans->queue, skb);
	tasklet_schedule(&trans->tasklet);
	return 0;
	}
	EXPORT_SYMBOL(xfrm_trans_queue_net);

	int xfrm_trans_queue(struct sk_buff *skb,
	int (finish)(struct net , struct sock *,
	struct sk_buff *))
	{
	return xfrm_trans_queue_net(dev_net(skb->dev), skb, finish);
	}
	EXPORT_SYMBOL(xfrm_trans_queue);

	void __init xfrm_input_init(void)
	{
	int err;
	int i;

	init_dummy_netdev(&xfrm_napi_dev);
	err = gro_cells_init(&gro_cells, &xfrm_napi_dev);
	if (err)
	gro_cells.cells = NULL;

	for_each_possible_cpu(i) {
	struct xfrm_trans_tasklet *trans;

	trans = &per_cpu(xfrm_trans_tasklet, i);
	__skb_queue_head_init(&trans->queue);
	tasklet_init(&trans->tasklet, xfrm_trans_reinject,
	(unsigned long)trans);
	}
	}