// SPDX-License-Identifier: GPL-2.0
  /*
   *	XFRM virtual interface
   *
   *	Copyright (C) 2018 secunet Security Networks AG
   *
   *	Author:
   *	Steffen Klassert <steffen.klassert@secunet.com>
   */
  
  #include <linux/module.h>
  #include <linux/capability.h>
  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/sockios.h>
  #include <linux/icmp.h>
  #include <linux/if.h>
  #include <linux/in.h>
  #include <linux/ip.h>
  #include <linux/net.h>
  #include <linux/in6.h>
  #include <linux/netdevice.h>
  #include <linux/if_link.h>
  #include <linux/if_arp.h>
  #include <linux/icmpv6.h>
  #include <linux/init.h>
  #include <linux/route.h>
  #include <linux/rtnetlink.h>
  #include <linux/netfilter_ipv6.h>
  #include <linux/slab.h>
  #include <linux/hash.h>
  
  #include <linux/uaccess.h>
  #include <linux/atomic.h>
  
  #include <net/icmp.h>
  #include <net/ip.h>
  #include <net/ipv6.h>
  #include <net/ip6_route.h>

  #include <net/ip_tunnels.h>

  #include <net/addrconf.h>
  #include <net/xfrm.h>
  #include <net/net_namespace.h>
  #include <net/netns/generic.h>
  #include <linux/etherdevice.h>
  
  static int xfrmi_dev_init(struct net_device *dev);
  static void xfrmi_dev_setup(struct net_device *dev);
  static struct rtnl_link_ops xfrmi_link_ops __read_mostly;
  static unsigned int xfrmi_net_id __read_mostly;

  static const struct net_device_ops xfrmi_netdev_ops;

  #define XFRMI_HASH_BITS	8
  #define XFRMI_HASH_SIZE	BIT(XFRMI_HASH_BITS)

  
  struct xfrmi_net {
  	/* lists for storing interfaces in use */

  	struct xfrm_if __rcu *xfrmi[XFRMI_HASH_SIZE];

  };
  
  #define for_each_xfrmi_rcu(start, xi) \
  	for (xi = rcu_dereference(start); xi; xi = rcu_dereference(xi->next))

  static u32 xfrmi_hash(u32 if_id)
  {
  	return hash_32(if_id, XFRMI_HASH_BITS);
  }

  static struct xfrm_if *xfrmi_lookup(struct net *net, struct xfrm_state *x)
  {
  	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
  	struct xfrm_if *xi;

  	for_each_xfrmi_rcu(xfrmn->xfrmi[xfrmi_hash(x->if_id)], xi) {

  		if (x->if_id == xi->p.if_id &&
  		    (xi->dev->flags & IFF_UP))
  			return xi;
  	}
  
  	return NULL;
  }

  static struct xfrm_if *xfrmi_decode_session(struct sk_buff *skb,
  					    unsigned short family)

  {

  	struct net_device *dev;

  	int ifindex = 0;

  	if (!secpath_exists(skb) || !skb->dev)

  		return NULL;

  	switch (family) {
  	case AF_INET6:
  		ifindex = inet6_sdif(skb);
  		break;
  	case AF_INET:
  		ifindex = inet_sdif(skb);
  		break;
  	}

  	if (ifindex) {
  		struct net *net = xs_net(xfrm_input_state(skb));

  		dev = dev_get_by_index_rcu(net, ifindex);
  	} else {
  		dev = skb->dev;

  	}

  	if (!dev || !(dev->flags & IFF_UP))
  		return NULL;
  	if (dev->netdev_ops != &xfrmi_netdev_ops)
  		return NULL;
  
  	return netdev_priv(dev);

  }
  
  static void xfrmi_link(struct xfrmi_net *xfrmn, struct xfrm_if *xi)
  {

  	struct xfrm_if __rcu **xip = &xfrmn->xfrmi[xfrmi_hash(xi->p.if_id)];

  
  	rcu_assign_pointer(xi->next , rtnl_dereference(*xip));
  	rcu_assign_pointer(*xip, xi);
  }
  
  static void xfrmi_unlink(struct xfrmi_net *xfrmn, struct xfrm_if *xi)
  {
  	struct xfrm_if __rcu **xip;
  	struct xfrm_if *iter;

  	for (xip = &xfrmn->xfrmi[xfrmi_hash(xi->p.if_id)];

  	     (iter = rtnl_dereference(*xip)) != NULL;
  	     xip = &iter->next) {
  		if (xi == iter) {
  			rcu_assign_pointer(*xip, xi->next);
  			break;
  		}
  	}
  }
  
  static void xfrmi_dev_free(struct net_device *dev)
  {

  	struct xfrm_if *xi = netdev_priv(dev);
  
  	gro_cells_destroy(&xi->gro_cells);

  	free_percpu(dev->tstats);
  }

  static int xfrmi_create(struct net_device *dev)

  {
  	struct xfrm_if *xi = netdev_priv(dev);
  	struct net *net = dev_net(dev);
  	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
  	int err;
  
  	dev->rtnl_link_ops = &xfrmi_link_ops;
  	err = register_netdevice(dev);
  	if (err < 0)
  		goto out;

  	xfrmi_link(xfrmn, xi);
  
  	return 0;
  
  out:
  	return err;
  }

  static struct xfrm_if *xfrmi_locate(struct net *net, struct xfrm_if_parms *p)

  {
  	struct xfrm_if __rcu **xip;
  	struct xfrm_if *xi;
  	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);

  	for (xip = &xfrmn->xfrmi[xfrmi_hash(p->if_id)];

  	     (xi = rtnl_dereference(*xip)) != NULL;

  	     xip = &xi->next)
  		if (xi->p.if_id == p->if_id)

  			return xi;

  
  	return NULL;

  }
  
  static void xfrmi_dev_uninit(struct net_device *dev)
  {
  	struct xfrm_if *xi = netdev_priv(dev);
  	struct xfrmi_net *xfrmn = net_generic(xi->net, xfrmi_net_id);
  
  	xfrmi_unlink(xfrmn, xi);

  }
  
  static void xfrmi_scrub_packet(struct sk_buff *skb, bool xnet)
  {
  	skb->tstamp = 0;
  	skb->pkt_type = PACKET_HOST;
  	skb->skb_iif = 0;
  	skb->ignore_df = 0;
  	skb_dst_drop(skb);

  	nf_reset_ct(skb);

  	nf_reset_trace(skb);
  
  	if (!xnet)
  		return;
  
  	ipvs_reset(skb);
  	secpath_reset(skb);
  	skb_orphan(skb);
  	skb->mark = 0;
  }
  
  static int xfrmi_rcv_cb(struct sk_buff *skb, int err)
  {

  	const struct xfrm_mode *inner_mode;

  	struct net_device *dev;
  	struct xfrm_state *x;
  	struct xfrm_if *xi;
  	bool xnet;

  	if (err && !secpath_exists(skb))

  		return 0;
  
  	x = xfrm_input_state(skb);
  
  	xi = xfrmi_lookup(xs_net(x), x);
  	if (!xi)
  		return 1;
  
  	dev = xi->dev;
  	skb->dev = dev;
  
  	if (err) {
  		dev->stats.rx_errors++;
  		dev->stats.rx_dropped++;
  
  		return 0;
  	}
  
  	xnet = !net_eq(xi->net, dev_net(skb->dev));
  
  	if (xnet) {

  		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(dev_net(skb->dev),
  					       LINUX_MIB_XFRMINSTATEMODEERROR);
  				return -EINVAL;
  			}
  		}
  
  		if (!xfrm_policy_check(NULL, XFRM_POLICY_IN, skb,

  				       inner_mode->family))

  			return -EPERM;
  	}
  
  	xfrmi_scrub_packet(skb, xnet);

  	dev_sw_netstats_rx_add(dev, skb->len);

  
  	return 0;
  }
  
  static int
  xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
  {
  	struct xfrm_if *xi = netdev_priv(dev);
  	struct net_device_stats *stats = &xi->dev->stats;
  	struct dst_entry *dst = skb_dst(skb);
  	unsigned int length = skb->len;
  	struct net_device *tdev;
  	struct xfrm_state *x;
  	int err = -1;
  	int mtu;

  	dst_hold(dst);

  	dst = xfrm_lookup_with_ifid(xi->net, dst, fl, NULL, 0, xi->p.if_id);

  	if (IS_ERR(dst)) {
  		err = PTR_ERR(dst);
  		dst = NULL;
  		goto tx_err_link_failure;
  	}
  
  	x = dst->xfrm;
  	if (!x)
  		goto tx_err_link_failure;
  
  	if (x->if_id != xi->p.if_id)
  		goto tx_err_link_failure;
  
  	tdev = dst->dev;
  
  	if (tdev == dev) {
  		stats->collisions++;
  		net_warn_ratelimited("%s: Local routing loop detected!
  ",

  				     dev->name);

  		goto tx_err_dst_release;
  	}
  
  	mtu = dst_mtu(dst);

  	if (skb->len > mtu) {

  		skb_dst_update_pmtu_no_confirm(skb, mtu);

  
  		if (skb->protocol == htons(ETH_P_IPV6)) {
  			if (mtu < IPV6_MIN_MTU)
  				mtu = IPV6_MIN_MTU;

  			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

  		} else {

  			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
  				      htonl(mtu));

  		}
  
  		dst_release(dst);
  		return -EMSGSIZE;
  	}
  
  	xfrmi_scrub_packet(skb, !net_eq(xi->net, dev_net(dev)));
  	skb_dst_set(skb, dst);
  	skb->dev = tdev;
  
  	err = dst_output(xi->net, skb->sk, skb);
  	if (net_xmit_eval(err) == 0) {
  		struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);
  
  		u64_stats_update_begin(&tstats->syncp);
  		tstats->tx_bytes += length;
  		tstats->tx_packets++;
  		u64_stats_update_end(&tstats->syncp);
  	} else {
  		stats->tx_errors++;
  		stats->tx_aborted_errors++;
  	}
  
  	return 0;
  tx_err_link_failure:
  	stats->tx_carrier_errors++;
  	dst_link_failure(skb);
  tx_err_dst_release:
  	dst_release(dst);
  	return err;
  }
  
  static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev)
  {
  	struct xfrm_if *xi = netdev_priv(dev);
  	struct net_device_stats *stats = &xi->dev->stats;

  	struct dst_entry *dst = skb_dst(skb);

  	struct flowi fl;
  	int ret;
  
  	memset(&fl, 0, sizeof(fl));
  
  	switch (skb->protocol) {
  	case htons(ETH_P_IPV6):
  		xfrm_decode_session(skb, &fl, AF_INET6);
  		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));

  		if (!dst) {
  			fl.u.ip6.flowi6_oif = dev->ifindex;
  			fl.u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC;
  			dst = ip6_route_output(dev_net(dev), NULL, &fl.u.ip6);
  			if (dst->error) {
  				dst_release(dst);
  				stats->tx_carrier_errors++;
  				goto tx_err;
  			}
  			skb_dst_set(skb, dst);
  		}

  		break;
  	case htons(ETH_P_IP):
  		xfrm_decode_session(skb, &fl, AF_INET);
  		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));

  		if (!dst) {
  			struct rtable *rt;
  
  			fl.u.ip4.flowi4_oif = dev->ifindex;
  			fl.u.ip4.flowi4_flags |= FLOWI_FLAG_ANYSRC;
  			rt = __ip_route_output_key(dev_net(dev), &fl.u.ip4);
  			if (IS_ERR(rt)) {
  				stats->tx_carrier_errors++;
  				goto tx_err;
  			}
  			skb_dst_set(skb, &rt->dst);
  		}

  		break;
  	default:
  		goto tx_err;
  	}

  	fl.flowi_oif = xi->p.link;

  
  	ret = xfrmi_xmit2(skb, dev, &fl);
  	if (ret < 0)
  		goto tx_err;
  
  	return NETDEV_TX_OK;
  
  tx_err:
  	stats->tx_errors++;
  	stats->tx_dropped++;
  	kfree_skb(skb);
  	return NETDEV_TX_OK;
  }
  
  static int xfrmi4_err(struct sk_buff *skb, u32 info)
  {
  	const struct iphdr *iph = (const struct iphdr *)skb->data;
  	struct net *net = dev_net(skb->dev);
  	int protocol = iph->protocol;
  	struct ip_comp_hdr *ipch;
  	struct ip_esp_hdr *esph;
  	struct ip_auth_hdr *ah ;
  	struct xfrm_state *x;
  	struct xfrm_if *xi;
  	__be32 spi;
  
  	switch (protocol) {
  	case IPPROTO_ESP:
  		esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
  		spi = esph->spi;
  		break;
  	case IPPROTO_AH:
  		ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
  		spi = ah->spi;
  		break;
  	case IPPROTO_COMP:
  		ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
  		spi = htonl(ntohs(ipch->cpi));
  		break;
  	default:
  		return 0;
  	}
  
  	switch (icmp_hdr(skb)->type) {
  	case ICMP_DEST_UNREACH:
  		if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
  			return 0;
  	case ICMP_REDIRECT:
  		break;
  	default:
  		return 0;
  	}
  
  	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
  			      spi, protocol, AF_INET);
  	if (!x)
  		return 0;
  
  	xi = xfrmi_lookup(net, x);
  	if (!xi) {
  		xfrm_state_put(x);
  		return -1;
  	}
  
  	if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)

  		ipv4_update_pmtu(skb, net, info, 0, protocol);

  	else

  		ipv4_redirect(skb, net, 0, protocol);

  	xfrm_state_put(x);
  
  	return 0;
  }
  
  static int xfrmi6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  		    u8 type, u8 code, int offset, __be32 info)
  {
  	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
  	struct net *net = dev_net(skb->dev);
  	int protocol = iph->nexthdr;
  	struct ip_comp_hdr *ipch;
  	struct ip_esp_hdr *esph;
  	struct ip_auth_hdr *ah;
  	struct xfrm_state *x;
  	struct xfrm_if *xi;
  	__be32 spi;
  
  	switch (protocol) {
  	case IPPROTO_ESP:
  		esph = (struct ip_esp_hdr *)(skb->data + offset);
  		spi = esph->spi;
  		break;
  	case IPPROTO_AH:
  		ah = (struct ip_auth_hdr *)(skb->data + offset);
  		spi = ah->spi;
  		break;
  	case IPPROTO_COMP:
  		ipch = (struct ip_comp_hdr *)(skb->data + offset);
  		spi = htonl(ntohs(ipch->cpi));
  		break;
  	default:
  		return 0;
  	}
  
  	if (type != ICMPV6_PKT_TOOBIG &&
  	    type != NDISC_REDIRECT)
  		return 0;
  
  	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
  			      spi, protocol, AF_INET6);
  	if (!x)
  		return 0;
  
  	xi = xfrmi_lookup(net, x);
  	if (!xi) {
  		xfrm_state_put(x);
  		return -1;
  	}
  
  	if (type == NDISC_REDIRECT)
  		ip6_redirect(skb, net, skb->dev->ifindex, 0,
  			     sock_net_uid(net, NULL));
  	else
  		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
  	xfrm_state_put(x);
  
  	return 0;
  }
  
  static int xfrmi_change(struct xfrm_if *xi, const struct xfrm_if_parms *p)
  {
  	if (xi->p.link != p->link)
  		return -EINVAL;
  
  	xi->p.if_id = p->if_id;
  
  	return 0;
  }
  
  static int xfrmi_update(struct xfrm_if *xi, struct xfrm_if_parms *p)
  {

  	struct net *net = xi->net;

  	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
  	int err;
  
  	xfrmi_unlink(xfrmn, xi);
  	synchronize_net();
  	err = xfrmi_change(xi, p);
  	xfrmi_link(xfrmn, xi);
  	netdev_state_change(xi->dev);
  	return err;
  }
  
  static void xfrmi_get_stats64(struct net_device *dev,
  			       struct rtnl_link_stats64 *s)
  {

  	dev_fetch_sw_netstats(s, dev->tstats);

  
  	s->rx_dropped = dev->stats.rx_dropped;
  	s->tx_dropped = dev->stats.tx_dropped;
  }
  
  static int xfrmi_get_iflink(const struct net_device *dev)
  {
  	struct xfrm_if *xi = netdev_priv(dev);

  	return xi->p.link;

  }
  
  
  static const struct net_device_ops xfrmi_netdev_ops = {
  	.ndo_init	= xfrmi_dev_init,
  	.ndo_uninit	= xfrmi_dev_uninit,
  	.ndo_start_xmit = xfrmi_xmit,
  	.ndo_get_stats64 = xfrmi_get_stats64,
  	.ndo_get_iflink = xfrmi_get_iflink,
  };
  
  static void xfrmi_dev_setup(struct net_device *dev)
  {
  	dev->netdev_ops 	= &xfrmi_netdev_ops;

  	dev->header_ops		= &ip_tunnel_header_ops;

  	dev->type		= ARPHRD_NONE;

  	dev->mtu		= ETH_DATA_LEN;
  	dev->min_mtu		= ETH_MIN_MTU;

  	dev->max_mtu		= IP_MAX_MTU;

  	dev->flags 		= IFF_NOARP;
  	dev->needs_free_netdev	= true;
  	dev->priv_destructor	= xfrmi_dev_free;
  	netif_keep_dst(dev);

  
  	eth_broadcast_addr(dev->broadcast);

  }
  
  static int xfrmi_dev_init(struct net_device *dev)
  {
  	struct xfrm_if *xi = netdev_priv(dev);

  	struct net_device *phydev = __dev_get_by_index(xi->net, xi->p.link);

  	int err;
  
  	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
  	if (!dev->tstats)
  		return -ENOMEM;
  
  	err = gro_cells_init(&xi->gro_cells, dev);
  	if (err) {
  		free_percpu(dev->tstats);
  		return err;
  	}
  
  	dev->features |= NETIF_F_LLTX;

  	if (phydev) {
  		dev->needed_headroom = phydev->needed_headroom;
  		dev->needed_tailroom = phydev->needed_tailroom;

  		if (is_zero_ether_addr(dev->dev_addr))
  			eth_hw_addr_inherit(dev, phydev);
  		if (is_zero_ether_addr(dev->broadcast))
  			memcpy(dev->broadcast, phydev->broadcast,
  			       dev->addr_len);
  	} else {
  		eth_hw_addr_random(dev);
  		eth_broadcast_addr(dev->broadcast);
  	}

  
  	return 0;
  }
  
  static int xfrmi_validate(struct nlattr *tb[], struct nlattr *data[],
  			 struct netlink_ext_ack *extack)
  {
  	return 0;
  }
  
  static void xfrmi_netlink_parms(struct nlattr *data[],
  			       struct xfrm_if_parms *parms)
  {
  	memset(parms, 0, sizeof(*parms));
  
  	if (!data)
  		return;
  
  	if (data[IFLA_XFRM_LINK])
  		parms->link = nla_get_u32(data[IFLA_XFRM_LINK]);
  
  	if (data[IFLA_XFRM_IF_ID])
  		parms->if_id = nla_get_u32(data[IFLA_XFRM_IF_ID]);
  }
  
  static int xfrmi_newlink(struct net *src_net, struct net_device *dev,
  			struct nlattr *tb[], struct nlattr *data[],
  			struct netlink_ext_ack *extack)
  {
  	struct net *net = dev_net(dev);

  	struct xfrm_if_parms p;

  	struct xfrm_if *xi;

  	int err;

  	xfrmi_netlink_parms(data, &p);

  	xi = xfrmi_locate(net, &p);
  	if (xi)
  		return -EEXIST;
  
  	xi = netdev_priv(dev);
  	xi->p = p;
  	xi->net = net;
  	xi->dev = dev;

  
  	err = xfrmi_create(dev);

  	return err;

  }
  
  static void xfrmi_dellink(struct net_device *dev, struct list_head *head)
  {
  	unregister_netdevice_queue(dev, head);
  }
  
  static int xfrmi_changelink(struct net_device *dev, struct nlattr *tb[],
  			   struct nlattr *data[],
  			   struct netlink_ext_ack *extack)
  {

  	struct xfrm_if *xi = netdev_priv(dev);
  	struct net *net = xi->net;

  	struct xfrm_if_parms p;

  	xfrmi_netlink_parms(data, &p);
  	xi = xfrmi_locate(net, &p);

  	if (!xi) {

  		xi = netdev_priv(dev);
  	} else {

  		if (xi->dev != dev)
  			return -EEXIST;

  	}

  	return xfrmi_update(xi, &p);

  }
  
  static size_t xfrmi_get_size(const struct net_device *dev)
  {
  	return
  		/* IFLA_XFRM_LINK */
  		nla_total_size(4) +
  		/* IFLA_XFRM_IF_ID */
  		nla_total_size(4) +
  		0;
  }
  
  static int xfrmi_fill_info(struct sk_buff *skb, const struct net_device *dev)
  {
  	struct xfrm_if *xi = netdev_priv(dev);
  	struct xfrm_if_parms *parm = &xi->p;
  
  	if (nla_put_u32(skb, IFLA_XFRM_LINK, parm->link) ||
  	    nla_put_u32(skb, IFLA_XFRM_IF_ID, parm->if_id))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }

  static struct net *xfrmi_get_link_net(const struct net_device *dev)

  {
  	struct xfrm_if *xi = netdev_priv(dev);

  	return xi->net;

  }
  
  static const struct nla_policy xfrmi_policy[IFLA_XFRM_MAX + 1] = {
  	[IFLA_XFRM_LINK]	= { .type = NLA_U32 },
  	[IFLA_XFRM_IF_ID]	= { .type = NLA_U32 },
  };
  
  static struct rtnl_link_ops xfrmi_link_ops __read_mostly = {
  	.kind		= "xfrm",
  	.maxtype	= IFLA_XFRM_MAX,
  	.policy		= xfrmi_policy,
  	.priv_size	= sizeof(struct xfrm_if),
  	.setup		= xfrmi_dev_setup,
  	.validate	= xfrmi_validate,
  	.newlink	= xfrmi_newlink,
  	.dellink	= xfrmi_dellink,
  	.changelink	= xfrmi_changelink,
  	.get_size	= xfrmi_get_size,
  	.fill_info	= xfrmi_fill_info,
  	.get_link_net	= xfrmi_get_link_net,
  };

  static void __net_exit xfrmi_exit_batch_net(struct list_head *net_exit_list)
  {
  	struct net *net;
  	LIST_HEAD(list);
  
  	rtnl_lock();
  	list_for_each_entry(net, net_exit_list, exit_list) {
  		struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
  		struct xfrm_if __rcu **xip;
  		struct xfrm_if *xi;

  		int i;

  		for (i = 0; i < XFRMI_HASH_SIZE; i++) {
  			for (xip = &xfrmn->xfrmi[i];
  			     (xi = rtnl_dereference(*xip)) != NULL;
  			     xip = &xi->next)
  				unregister_netdevice_queue(xi->dev, &list);
  		}

  	}
  	unregister_netdevice_many(&list);
  	rtnl_unlock();
  }

  static struct pernet_operations xfrmi_net_ops = {

  	.exit_batch = xfrmi_exit_batch_net,

  	.id   = &xfrmi_net_id,
  	.size = sizeof(struct xfrmi_net),
  };
  
  static struct xfrm6_protocol xfrmi_esp6_protocol __read_mostly = {
  	.handler	=	xfrm6_rcv,

  	.input_handler	=	xfrm_input,

  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi6_err,
  	.priority	=	10,
  };
  
  static struct xfrm6_protocol xfrmi_ah6_protocol __read_mostly = {
  	.handler	=	xfrm6_rcv,

  	.input_handler	=	xfrm_input,

  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi6_err,
  	.priority	=	10,
  };
  
  static struct xfrm6_protocol xfrmi_ipcomp6_protocol __read_mostly = {
  	.handler	=	xfrm6_rcv,

  	.input_handler	=	xfrm_input,

  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi6_err,
  	.priority	=	10,
  };

  #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)

  static int xfrmi6_rcv_tunnel(struct sk_buff *skb)
  {
  	const xfrm_address_t *saddr;
  	__be32 spi;
  
  	saddr = (const xfrm_address_t *)&ipv6_hdr(skb)->saddr;
  	spi = xfrm6_tunnel_spi_lookup(dev_net(skb->dev), saddr);
  
  	return xfrm6_rcv_spi(skb, IPPROTO_IPV6, spi, NULL);
  }
  
  static struct xfrm6_tunnel xfrmi_ipv6_handler __read_mostly = {
  	.handler	=	xfrmi6_rcv_tunnel,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi6_err,

  	.priority	=	2,

  };

  
  static struct xfrm6_tunnel xfrmi_ip6ip_handler __read_mostly = {
  	.handler	=	xfrmi6_rcv_tunnel,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi6_err,

  	.priority	=	2,

  };

  #endif

  static struct xfrm4_protocol xfrmi_esp4_protocol __read_mostly = {
  	.handler	=	xfrm4_rcv,
  	.input_handler	=	xfrm_input,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi4_err,
  	.priority	=	10,
  };
  
  static struct xfrm4_protocol xfrmi_ah4_protocol __read_mostly = {
  	.handler	=	xfrm4_rcv,
  	.input_handler	=	xfrm_input,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi4_err,
  	.priority	=	10,
  };
  
  static struct xfrm4_protocol xfrmi_ipcomp4_protocol __read_mostly = {
  	.handler	=	xfrm4_rcv,
  	.input_handler	=	xfrm_input,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi4_err,
  	.priority	=	10,
  };

  #if IS_REACHABLE(CONFIG_INET_XFRM_TUNNEL)

  static int xfrmi4_rcv_tunnel(struct sk_buff *skb)
  {
  	return xfrm4_rcv_spi(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr);
  }
  
  static struct xfrm_tunnel xfrmi_ipip_handler __read_mostly = {
  	.handler	=	xfrmi4_rcv_tunnel,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi4_err,

  	.priority	=	3,

  };

  
  static struct xfrm_tunnel xfrmi_ipip6_handler __read_mostly = {
  	.handler	=	xfrmi4_rcv_tunnel,
  	.cb_handler	=	xfrmi_rcv_cb,
  	.err_handler	=	xfrmi4_err,

  	.priority	=	2,

  };

  #endif

  static int __init xfrmi4_init(void)
  {
  	int err;
  
  	err = xfrm4_protocol_register(&xfrmi_esp4_protocol, IPPROTO_ESP);
  	if (err < 0)
  		goto xfrm_proto_esp_failed;
  	err = xfrm4_protocol_register(&xfrmi_ah4_protocol, IPPROTO_AH);
  	if (err < 0)
  		goto xfrm_proto_ah_failed;
  	err = xfrm4_protocol_register(&xfrmi_ipcomp4_protocol, IPPROTO_COMP);
  	if (err < 0)
  		goto xfrm_proto_comp_failed;

  #if IS_REACHABLE(CONFIG_INET_XFRM_TUNNEL)

  	err = xfrm4_tunnel_register(&xfrmi_ipip_handler, AF_INET);
  	if (err < 0)
  		goto xfrm_tunnel_ipip_failed;

  	err = xfrm4_tunnel_register(&xfrmi_ipip6_handler, AF_INET6);

  	if (err < 0)
  		goto xfrm_tunnel_ipip6_failed;
  #endif

  
  	return 0;

  #if IS_REACHABLE(CONFIG_INET_XFRM_TUNNEL)

  xfrm_tunnel_ipip6_failed:
  	xfrm4_tunnel_deregister(&xfrmi_ipip_handler, AF_INET);
  xfrm_tunnel_ipip_failed:
  	xfrm4_protocol_deregister(&xfrmi_ipcomp4_protocol, IPPROTO_COMP);
  #endif

  xfrm_proto_comp_failed:
  	xfrm4_protocol_deregister(&xfrmi_ah4_protocol, IPPROTO_AH);
  xfrm_proto_ah_failed:
  	xfrm4_protocol_deregister(&xfrmi_esp4_protocol, IPPROTO_ESP);
  xfrm_proto_esp_failed:
  	return err;
  }
  
  static void xfrmi4_fini(void)
  {

  #if IS_REACHABLE(CONFIG_INET_XFRM_TUNNEL)

  	xfrm4_tunnel_deregister(&xfrmi_ipip6_handler, AF_INET6);

  	xfrm4_tunnel_deregister(&xfrmi_ipip_handler, AF_INET);
  #endif

  	xfrm4_protocol_deregister(&xfrmi_ipcomp4_protocol, IPPROTO_COMP);
  	xfrm4_protocol_deregister(&xfrmi_ah4_protocol, IPPROTO_AH);
  	xfrm4_protocol_deregister(&xfrmi_esp4_protocol, IPPROTO_ESP);
  }
  
  static int __init xfrmi6_init(void)
  {
  	int err;
  
  	err = xfrm6_protocol_register(&xfrmi_esp6_protocol, IPPROTO_ESP);
  	if (err < 0)
  		goto xfrm_proto_esp_failed;
  	err = xfrm6_protocol_register(&xfrmi_ah6_protocol, IPPROTO_AH);
  	if (err < 0)
  		goto xfrm_proto_ah_failed;
  	err = xfrm6_protocol_register(&xfrmi_ipcomp6_protocol, IPPROTO_COMP);
  	if (err < 0)
  		goto xfrm_proto_comp_failed;

  #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)

  	err = xfrm6_tunnel_register(&xfrmi_ipv6_handler, AF_INET6);
  	if (err < 0)
  		goto xfrm_tunnel_ipv6_failed;

  	err = xfrm6_tunnel_register(&xfrmi_ip6ip_handler, AF_INET);

  	if (err < 0)
  		goto xfrm_tunnel_ip6ip_failed;
  #endif

  
  	return 0;

  #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)

  xfrm_tunnel_ip6ip_failed:
  	xfrm6_tunnel_deregister(&xfrmi_ipv6_handler, AF_INET6);
  xfrm_tunnel_ipv6_failed:
  	xfrm6_protocol_deregister(&xfrmi_ipcomp6_protocol, IPPROTO_COMP);
  #endif

  xfrm_proto_comp_failed:
  	xfrm6_protocol_deregister(&xfrmi_ah6_protocol, IPPROTO_AH);
  xfrm_proto_ah_failed:
  	xfrm6_protocol_deregister(&xfrmi_esp6_protocol, IPPROTO_ESP);
  xfrm_proto_esp_failed:
  	return err;
  }
  
  static void xfrmi6_fini(void)
  {

  #if IS_REACHABLE(CONFIG_INET6_XFRM_TUNNEL)

  	xfrm6_tunnel_deregister(&xfrmi_ip6ip_handler, AF_INET);

  	xfrm6_tunnel_deregister(&xfrmi_ipv6_handler, AF_INET6);
  #endif

  	xfrm6_protocol_deregister(&xfrmi_ipcomp6_protocol, IPPROTO_COMP);
  	xfrm6_protocol_deregister(&xfrmi_ah6_protocol, IPPROTO_AH);
  	xfrm6_protocol_deregister(&xfrmi_esp6_protocol, IPPROTO_ESP);
  }
  
  static const struct xfrm_if_cb xfrm_if_cb = {
  	.decode_session =	xfrmi_decode_session,
  };
  
  static int __init xfrmi_init(void)
  {
  	const char *msg;
  	int err;
  
  	pr_info("IPsec XFRM device driver
  ");
  
  	msg = "tunnel device";
  	err = register_pernet_device(&xfrmi_net_ops);
  	if (err < 0)
  		goto pernet_dev_failed;
  
  	msg = "xfrm4 protocols";
  	err = xfrmi4_init();
  	if (err < 0)
  		goto xfrmi4_failed;
  
  	msg = "xfrm6 protocols";
  	err = xfrmi6_init();
  	if (err < 0)
  		goto xfrmi6_failed;
  
  
  	msg = "netlink interface";
  	err = rtnl_link_register(&xfrmi_link_ops);
  	if (err < 0)
  		goto rtnl_link_failed;
  
  	xfrm_if_register_cb(&xfrm_if_cb);
  
  	return err;
  
  rtnl_link_failed:
  	xfrmi6_fini();
  xfrmi6_failed:
  	xfrmi4_fini();
  xfrmi4_failed:
  	unregister_pernet_device(&xfrmi_net_ops);
  pernet_dev_failed:
  	pr_err("xfrmi init: failed to register %s
  ", msg);
  	return err;
  }
  
  static void __exit xfrmi_fini(void)
  {
  	xfrm_if_unregister_cb();
  	rtnl_link_unregister(&xfrmi_link_ops);
  	xfrmi4_fini();
  	xfrmi6_fini();
  	unregister_pernet_device(&xfrmi_net_ops);
  }
  
  module_init(xfrmi_init);
  module_exit(xfrmi_fini);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_RTNL_LINK("xfrm");
  MODULE_ALIAS_NETDEV("xfrm0");
  MODULE_AUTHOR("Steffen Klassert");
  MODULE_DESCRIPTION("XFRM virtual interface");