1 files changed, 726 insertions, 0 deletions

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
new file mode 100644
index 000000000..615c1dcf3
--- /dev/null
+++ b/net/ipv4/ip_vti.c
@@ -0,0 +1,726 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Linux NET3: IP/IP protocol decoder modified to support
+ *		    virtual tunnel interface
+ *
+ *	Authors:
+ *		Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
+ */
+
+/*
+   This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
+
+   For comments look at net/ipv4/ip_gre.c --ANK
+ */
+
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/if_arp.h>
+#include <linux/init.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/if_ether.h>
+#include <linux/icmpv6.h>
+
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/ip_tunnels.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
+static struct rtnl_link_ops vti_link_ops __read_mostly;
+
+static unsigned int vti_net_id __read_mostly;
+static int vti_tunnel_init(struct net_device *dev);
+
+static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
+		     int encap_type, bool update_skb_dev)
+{
+	struct ip_tunnel *tunnel;
+	const struct iphdr *iph = ip_hdr(skb);
+	struct net *net = dev_net(skb->dev);
+	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
+
+	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
+				  iph->saddr, iph->daddr, 0);
+	if (tunnel) {
+		if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+			goto drop;
+
+		XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
+
+		if (update_skb_dev)
+			skb->dev = tunnel->dev;
+
+		return xfrm_input(skb, nexthdr, spi, encap_type);
+	}
+
+	return -EINVAL;
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static int vti_input_proto(struct sk_buff *skb, int nexthdr, __be32 spi,
+			   int encap_type)
+{
+	return vti_input(skb, nexthdr, spi, encap_type, false);
+}
+
+static int vti_rcv(struct sk_buff *skb, __be32 spi, bool update_skb_dev)
+{
+	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
+	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
+
+	return vti_input(skb, ip_hdr(skb)->protocol, spi, 0, update_skb_dev);
+}
+
+static int vti_rcv_proto(struct sk_buff *skb)
+{
+	return vti_rcv(skb, 0, false);
+}
+
+static int vti_rcv_cb(struct sk_buff *skb, int err)
+{
+	unsigned short family;
+	struct net_device *dev;
+	struct xfrm_state *x;
+	const struct xfrm_mode *inner_mode;
+	struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
+	u32 orig_mark = skb->mark;
+	int ret;
+
+	if (!tunnel)
+		return 1;
+
+	dev = tunnel->dev;
+
+	if (err) {
+		dev->stats.rx_errors++;
+		dev->stats.rx_dropped++;
+
+		return 0;
+	}
+
+	x = xfrm_input_state(skb);
+
+	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;
+		}
+	}
+
+	family = inner_mode->family;
+
+	skb->mark = be32_to_cpu(tunnel->parms.i_key);
+	ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
+	skb->mark = orig_mark;
+
+	if (!ret)
+		return -EPERM;
+
+	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
+	skb->dev = dev;
+	dev_sw_netstats_rx_add(dev, skb->len);
+
+	return 0;
+}
+
+static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
+{
+	xfrm_address_t *daddr = (xfrm_address_t *)&dst;
+	xfrm_address_t *saddr = (xfrm_address_t *)&src;
+
+	/* if there is no transform then this tunnel is not functional.
+	 * Or if the xfrm is not mode tunnel.
+	 */
+	if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
+	    x->props.family != AF_INET)
+		return false;
+
+	if (!dst)
+		return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
+
+	if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
+		return false;
+
+	return true;
+}
+
+static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
+			    struct flowi *fl)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct ip_tunnel_parm *parms = &tunnel->parms;
+	struct dst_entry *dst = skb_dst(skb);
+	struct net_device *tdev;	/* Device to other host */
+	int pkt_len = skb->len;
+	int err;
+	int mtu;
+
+	if (!dst) {
+		switch (skb->protocol) {
+		case htons(ETH_P_IP): {
+			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)) {
+				dev->stats.tx_carrier_errors++;
+				goto tx_error_icmp;
+			}
+			dst = &rt->dst;
+			skb_dst_set(skb, dst);
+			break;
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		case htons(ETH_P_IPV6):
+			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);
+				dst = NULL;
+				dev->stats.tx_carrier_errors++;
+				goto tx_error_icmp;
+			}
+			skb_dst_set(skb, dst);
+			break;
+#endif
+		default:
+			dev->stats.tx_carrier_errors++;
+			goto tx_error_icmp;
+		}
+	}
+
+	dst_hold(dst);
+	dst = xfrm_lookup_route(tunnel->net, dst, fl, NULL, 0);
+	if (IS_ERR(dst)) {
+		dev->stats.tx_carrier_errors++;
+		goto tx_error_icmp;
+	}
+
+	if (dst->flags & DST_XFRM_QUEUE)
+		goto xmit;
+
+	if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
+		dev->stats.tx_carrier_errors++;
+		dst_release(dst);
+		goto tx_error_icmp;
+	}
+
+	tdev = dst->dev;
+
+	if (tdev == dev) {
+		dst_release(dst);
+		dev->stats.collisions++;
+		goto tx_error;
+	}
+
+	mtu = dst_mtu(dst);
+	if (skb->len > mtu) {
+		skb_dst_update_pmtu_no_confirm(skb, mtu);
+		if (skb->protocol == htons(ETH_P_IP)) {
+			if (!(ip_hdr(skb)->frag_off & htons(IP_DF)))
+				goto xmit;
+			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				      htonl(mtu));
+		} else {
+			if (mtu < IPV6_MIN_MTU)
+				mtu = IPV6_MIN_MTU;
+
+			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+		}
+
+		dst_release(dst);
+		goto tx_error;
+	}
+
+xmit:
+	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
+	skb_dst_set(skb, dst);
+	skb->dev = skb_dst(skb)->dev;
+
+	err = dst_output(tunnel->net, skb->sk, skb);
+	if (net_xmit_eval(err) == 0)
+		err = pkt_len;
+	iptunnel_xmit_stats(dev, err);
+	return NETDEV_TX_OK;
+
+tx_error_icmp:
+	dst_link_failure(skb);
+tx_error:
+	dev->stats.tx_errors++;
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+/* This function assumes it is being called from dev_queue_xmit()
+ * and that skb is filled properly by that function.
+ */
+static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct flowi fl;
+
+	if (!pskb_inet_may_pull(skb))
+		goto tx_err;
+
+	memset(&fl, 0, sizeof(fl));
+
+	switch (skb->protocol) {
+	case htons(ETH_P_IP):
+		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET);
+		break;
+	case htons(ETH_P_IPV6):
+		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET6);
+		break;
+	default:
+		goto tx_err;
+	}
+
+	/* override mark with tunnel output key */
+	fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
+
+	return vti_xmit(skb, dev, &fl);
+
+tx_err:
+	dev->stats.tx_errors++;
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static int vti4_err(struct sk_buff *skb, u32 info)
+{
+	__be32 spi;
+	__u32 mark;
+	struct xfrm_state *x;
+	struct ip_tunnel *tunnel;
+	struct ip_esp_hdr *esph;
+	struct ip_auth_hdr *ah ;
+	struct ip_comp_hdr *ipch;
+	struct net *net = dev_net(skb->dev);
+	const struct iphdr *iph = (const struct iphdr *)skb->data;
+	int protocol = iph->protocol;
+	struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
+
+	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
+				  iph->daddr, iph->saddr, 0);
+	if (!tunnel)
+		return -1;
+
+	mark = be32_to_cpu(tunnel->parms.o_key);
+
+	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;
+		break;
+	case ICMP_REDIRECT:
+		break;
+	default:
+		return 0;
+	}
+
+	x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
+			      spi, protocol, AF_INET);
+	if (!x)
+		return 0;
+
+	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
+vti_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
+{
+	int err = 0;
+
+	if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
+		if (p->iph.version != 4 || p->iph.protocol != IPPROTO_IPIP ||
+		    p->iph.ihl != 5)
+			return -EINVAL;
+	}
+
+	if (!(p->i_flags & GRE_KEY))
+		p->i_key = 0;
+	if (!(p->o_flags & GRE_KEY))
+		p->o_key = 0;
+
+	p->i_flags = VTI_ISVTI;
+
+	err = ip_tunnel_ctl(dev, p, cmd);
+	if (err)
+		return err;
+
+	if (cmd != SIOCDELTUNNEL) {
+		p->i_flags |= GRE_KEY;
+		p->o_flags |= GRE_KEY;
+	}
+	return 0;
+}
+
+static const struct net_device_ops vti_netdev_ops = {
+	.ndo_init	= vti_tunnel_init,
+	.ndo_uninit	= ip_tunnel_uninit,
+	.ndo_start_xmit	= vti_tunnel_xmit,
+	.ndo_siocdevprivate = ip_tunnel_siocdevprivate,
+	.ndo_change_mtu	= ip_tunnel_change_mtu,
+	.ndo_get_stats64 = dev_get_tstats64,
+	.ndo_get_iflink = ip_tunnel_get_iflink,
+	.ndo_tunnel_ctl	= vti_tunnel_ctl,
+};
+
+static void vti_tunnel_setup(struct net_device *dev)
+{
+	dev->netdev_ops		= &vti_netdev_ops;
+	dev->header_ops		= &ip_tunnel_header_ops;
+	dev->type		= ARPHRD_TUNNEL;
+	ip_tunnel_setup(dev, vti_net_id);
+}
+
+static int vti_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct iphdr *iph = &tunnel->parms.iph;
+
+	__dev_addr_set(dev, &iph->saddr, 4);
+	memcpy(dev->broadcast, &iph->daddr, 4);
+
+	dev->flags		= IFF_NOARP;
+	dev->addr_len		= 4;
+	dev->features		|= NETIF_F_LLTX;
+	netif_keep_dst(dev);
+
+	return ip_tunnel_init(dev);
+}
+
+static void __net_init vti_fb_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct iphdr *iph = &tunnel->parms.iph;
+
+	iph->version		= 4;
+	iph->protocol		= IPPROTO_IPIP;
+	iph->ihl		= 5;
+}
+
+static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
+	.handler	=	vti_rcv_proto,
+	.input_handler	=	vti_input_proto,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	100,
+};
+
+static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
+	.handler	=	vti_rcv_proto,
+	.input_handler	=	vti_input_proto,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	100,
+};
+
+static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
+	.handler	=	vti_rcv_proto,
+	.input_handler	=	vti_input_proto,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	100,
+};
+
+#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
+static int vti_rcv_tunnel(struct sk_buff *skb)
+{
+	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
+	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
+
+	return vti_input(skb, IPPROTO_IPIP, ip_hdr(skb)->saddr, 0, false);
+}
+
+static struct xfrm_tunnel vti_ipip_handler __read_mostly = {
+	.handler	=	vti_rcv_tunnel,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	0,
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+static struct xfrm_tunnel vti_ipip6_handler __read_mostly = {
+	.handler	=	vti_rcv_tunnel,
+	.cb_handler	=	vti_rcv_cb,
+	.err_handler	=	vti4_err,
+	.priority	=	0,
+};
+#endif
+#endif
+
+static int __net_init vti_init_net(struct net *net)
+{
+	int err;
+	struct ip_tunnel_net *itn;
+
+	err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
+	if (err)
+		return err;
+	itn = net_generic(net, vti_net_id);
+	if (itn->fb_tunnel_dev)
+		vti_fb_tunnel_init(itn->fb_tunnel_dev);
+	return 0;
+}
+
+static void __net_exit vti_exit_batch_net(struct list_head *list_net)
+{
+	ip_tunnel_delete_nets(list_net, vti_net_id, &vti_link_ops);
+}
+
+static struct pernet_operations vti_net_ops = {
+	.init = vti_init_net,
+	.exit_batch = vti_exit_batch_net,
+	.id   = &vti_net_id,
+	.size = sizeof(struct ip_tunnel_net),
+};
+
+static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
+			       struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static void vti_netlink_parms(struct nlattr *data[],
+			      struct ip_tunnel_parm *parms,
+			      __u32 *fwmark)
+{
+	memset(parms, 0, sizeof(*parms));
+
+	parms->iph.protocol = IPPROTO_IPIP;
+
+	if (!data)
+		return;
+
+	parms->i_flags = VTI_ISVTI;
+
+	if (data[IFLA_VTI_LINK])
+		parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
+
+	if (data[IFLA_VTI_IKEY])
+		parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
+
+	if (data[IFLA_VTI_OKEY])
+		parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
+
+	if (data[IFLA_VTI_LOCAL])
+		parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
+
+	if (data[IFLA_VTI_REMOTE])
+		parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
+
+	if (data[IFLA_VTI_FWMARK])
+		*fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
+}
+
+static int vti_newlink(struct net *src_net, struct net_device *dev,
+		       struct nlattr *tb[], struct nlattr *data[],
+		       struct netlink_ext_ack *extack)
+{
+	struct ip_tunnel_parm parms;
+	__u32 fwmark = 0;
+
+	vti_netlink_parms(data, &parms, &fwmark);
+	return ip_tunnel_newlink(dev, tb, &parms, fwmark);
+}
+
+static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
+			  struct nlattr *data[],
+			  struct netlink_ext_ack *extack)
+{
+	struct ip_tunnel *t = netdev_priv(dev);
+	__u32 fwmark = t->fwmark;
+	struct ip_tunnel_parm p;
+
+	vti_netlink_parms(data, &p, &fwmark);
+	return ip_tunnel_changelink(dev, tb, &p, fwmark);
+}
+
+static size_t vti_get_size(const struct net_device *dev)
+{
+	return
+		/* IFLA_VTI_LINK */
+		nla_total_size(4) +
+		/* IFLA_VTI_IKEY */
+		nla_total_size(4) +
+		/* IFLA_VTI_OKEY */
+		nla_total_size(4) +
+		/* IFLA_VTI_LOCAL */
+		nla_total_size(4) +
+		/* IFLA_VTI_REMOTE */
+		nla_total_size(4) +
+		/* IFLA_VTI_FWMARK */
+		nla_total_size(4) +
+		0;
+}
+
+static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+	struct ip_tunnel *t = netdev_priv(dev);
+	struct ip_tunnel_parm *p = &t->parms;
+
+	if (nla_put_u32(skb, IFLA_VTI_LINK, p->link) ||
+	    nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key) ||
+	    nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key) ||
+	    nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr) ||
+	    nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr) ||
+	    nla_put_u32(skb, IFLA_VTI_FWMARK, t->fwmark))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
+	[IFLA_VTI_LINK]		= { .type = NLA_U32 },
+	[IFLA_VTI_IKEY]		= { .type = NLA_U32 },
+	[IFLA_VTI_OKEY]		= { .type = NLA_U32 },
+	[IFLA_VTI_LOCAL]	= { .len = sizeof_field(struct iphdr, saddr) },
+	[IFLA_VTI_REMOTE]	= { .len = sizeof_field(struct iphdr, daddr) },
+	[IFLA_VTI_FWMARK]	= { .type = NLA_U32 },
+};
+
+static struct rtnl_link_ops vti_link_ops __read_mostly = {
+	.kind		= "vti",
+	.maxtype	= IFLA_VTI_MAX,
+	.policy		= vti_policy,
+	.priv_size	= sizeof(struct ip_tunnel),
+	.setup		= vti_tunnel_setup,
+	.validate	= vti_tunnel_validate,
+	.newlink	= vti_newlink,
+	.changelink	= vti_changelink,
+	.dellink        = ip_tunnel_dellink,
+	.get_size	= vti_get_size,
+	.fill_info	= vti_fill_info,
+	.get_link_net	= ip_tunnel_get_link_net,
+};
+
+static int __init vti_init(void)
+{
+	const char *msg;
+	int err;
+
+	pr_info("IPv4 over IPsec tunneling driver\n");
+
+	msg = "tunnel device";
+	err = register_pernet_device(&vti_net_ops);
+	if (err < 0)
+		goto pernet_dev_failed;
+
+	msg = "tunnel protocols";
+	err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
+	if (err < 0)
+		goto xfrm_proto_esp_failed;
+	err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
+	if (err < 0)
+		goto xfrm_proto_ah_failed;
+	err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
+	if (err < 0)
+		goto xfrm_proto_comp_failed;
+
+#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
+	msg = "ipip tunnel";
+	err = xfrm4_tunnel_register(&vti_ipip_handler, AF_INET);
+	if (err < 0)
+		goto xfrm_tunnel_ipip_failed;
+#if IS_ENABLED(CONFIG_IPV6)
+	err = xfrm4_tunnel_register(&vti_ipip6_handler, AF_INET6);
+	if (err < 0)
+		goto xfrm_tunnel_ipip6_failed;
+#endif
+#endif
+
+	msg = "netlink interface";
+	err = rtnl_link_register(&vti_link_ops);
+	if (err < 0)
+		goto rtnl_link_failed;
+
+	return err;
+
+rtnl_link_failed:
+#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
+#if IS_ENABLED(CONFIG_IPV6)
+	xfrm4_tunnel_deregister(&vti_ipip6_handler, AF_INET6);
+xfrm_tunnel_ipip6_failed:
+#endif
+	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET);
+xfrm_tunnel_ipip_failed:
+#endif
+	xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
+xfrm_proto_comp_failed:
+	xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
+xfrm_proto_ah_failed:
+	xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
+xfrm_proto_esp_failed:
+	unregister_pernet_device(&vti_net_ops);
+pernet_dev_failed:
+	pr_err("vti init: failed to register %s\n", msg);
+	return err;
+}
+
+static void __exit vti_fini(void)
+{
+	rtnl_link_unregister(&vti_link_ops);
+#if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
+#if IS_ENABLED(CONFIG_IPV6)
+	xfrm4_tunnel_deregister(&vti_ipip6_handler, AF_INET6);
+#endif
+	xfrm4_tunnel_deregister(&vti_ipip_handler, AF_INET);
+#endif
+	xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
+	xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
+	xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
+	unregister_pernet_device(&vti_net_ops);
+}
+
+module_init(vti_init);
+module_exit(vti_fini);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_RTNL_LINK("vti");
+MODULE_ALIAS_NETDEV("ip_vti0");