Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 1301 insertions, 0 deletions

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
new file mode 100644
index 0000000000..beeae624c4
--- /dev/null
+++ b/net/ipv4/ip_tunnel.c
@@ -0,0 +1,1301 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013 Nicira, Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.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/in6.h>
+#include <linux/inetdevice.h>
+#include <linux/igmp.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/if_vlan.h>
+#include <linux/rculist.h>
+#include <linux/err.h>
+
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/protocol.h>
+#include <net/ip_tunnels.h>
+#include <net/arp.h>
+#include <net/checksum.h>
+#include <net/dsfield.h>
+#include <net/inet_ecn.h>
+#include <net/xfrm.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+#include <net/udp.h>
+#include <net/dst_metadata.h>
+
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/ipv6.h>
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+#endif
+
+static unsigned int ip_tunnel_hash(__be32 key, __be32 remote)
+{
+	return hash_32((__force u32)key ^ (__force u32)remote,
+			 IP_TNL_HASH_BITS);
+}
+
+static bool ip_tunnel_key_match(const struct ip_tunnel_parm *p,
+				__be16 flags, __be32 key)
+{
+	if (p->i_flags & TUNNEL_KEY) {
+		if (flags & TUNNEL_KEY)
+			return key == p->i_key;
+		else
+			/* key expected, none present */
+			return false;
+	} else
+		return !(flags & TUNNEL_KEY);
+}
+
+/* Fallback tunnel: no source, no destination, no key, no options
+
+   Tunnel hash table:
+   We require exact key match i.e. if a key is present in packet
+   it will match only tunnel with the same key; if it is not present,
+   it will match only keyless tunnel.
+
+   All keysless packets, if not matched configured keyless tunnels
+   will match fallback tunnel.
+   Given src, dst and key, find appropriate for input tunnel.
+*/
+struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
+				   int link, __be16 flags,
+				   __be32 remote, __be32 local,
+				   __be32 key)
+{
+	struct ip_tunnel *t, *cand = NULL;
+	struct hlist_head *head;
+	struct net_device *ndev;
+	unsigned int hash;
+
+	hash = ip_tunnel_hash(key, remote);
+	head = &itn->tunnels[hash];
+
+	hlist_for_each_entry_rcu(t, head, hash_node) {
+		if (local != t->parms.iph.saddr ||
+		    remote != t->parms.iph.daddr ||
+		    !(t->dev->flags & IFF_UP))
+			continue;
+
+		if (!ip_tunnel_key_match(&t->parms, flags, key))
+			continue;
+
+		if (t->parms.link == link)
+			return t;
+		else
+			cand = t;
+	}
+
+	hlist_for_each_entry_rcu(t, head, hash_node) {
+		if (remote != t->parms.iph.daddr ||
+		    t->parms.iph.saddr != 0 ||
+		    !(t->dev->flags & IFF_UP))
+			continue;
+
+		if (!ip_tunnel_key_match(&t->parms, flags, key))
+			continue;
+
+		if (t->parms.link == link)
+			return t;
+		else if (!cand)
+			cand = t;
+	}
+
+	hash = ip_tunnel_hash(key, 0);
+	head = &itn->tunnels[hash];
+
+	hlist_for_each_entry_rcu(t, head, hash_node) {
+		if ((local != t->parms.iph.saddr || t->parms.iph.daddr != 0) &&
+		    (local != t->parms.iph.daddr || !ipv4_is_multicast(local)))
+			continue;
+
+		if (!(t->dev->flags & IFF_UP))
+			continue;
+
+		if (!ip_tunnel_key_match(&t->parms, flags, key))
+			continue;
+
+		if (t->parms.link == link)
+			return t;
+		else if (!cand)
+			cand = t;
+	}
+
+	hlist_for_each_entry_rcu(t, head, hash_node) {
+		if ((!(flags & TUNNEL_NO_KEY) && t->parms.i_key != key) ||
+		    t->parms.iph.saddr != 0 ||
+		    t->parms.iph.daddr != 0 ||
+		    !(t->dev->flags & IFF_UP))
+			continue;
+
+		if (t->parms.link == link)
+			return t;
+		else if (!cand)
+			cand = t;
+	}
+
+	if (cand)
+		return cand;
+
+	t = rcu_dereference(itn->collect_md_tun);
+	if (t && t->dev->flags & IFF_UP)
+		return t;
+
+	ndev = READ_ONCE(itn->fb_tunnel_dev);
+	if (ndev && ndev->flags & IFF_UP)
+		return netdev_priv(ndev);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_lookup);
+
+static struct hlist_head *ip_bucket(struct ip_tunnel_net *itn,
+				    struct ip_tunnel_parm *parms)
+{
+	unsigned int h;
+	__be32 remote;
+	__be32 i_key = parms->i_key;
+
+	if (parms->iph.daddr && !ipv4_is_multicast(parms->iph.daddr))
+		remote = parms->iph.daddr;
+	else
+		remote = 0;
+
+	if (!(parms->i_flags & TUNNEL_KEY) && (parms->i_flags & VTI_ISVTI))
+		i_key = 0;
+
+	h = ip_tunnel_hash(i_key, remote);
+	return &itn->tunnels[h];
+}
+
+static void ip_tunnel_add(struct ip_tunnel_net *itn, struct ip_tunnel *t)
+{
+	struct hlist_head *head = ip_bucket(itn, &t->parms);
+
+	if (t->collect_md)
+		rcu_assign_pointer(itn->collect_md_tun, t);
+	hlist_add_head_rcu(&t->hash_node, head);
+}
+
+static void ip_tunnel_del(struct ip_tunnel_net *itn, struct ip_tunnel *t)
+{
+	if (t->collect_md)
+		rcu_assign_pointer(itn->collect_md_tun, NULL);
+	hlist_del_init_rcu(&t->hash_node);
+}
+
+static struct ip_tunnel *ip_tunnel_find(struct ip_tunnel_net *itn,
+					struct ip_tunnel_parm *parms,
+					int type)
+{
+	__be32 remote = parms->iph.daddr;
+	__be32 local = parms->iph.saddr;
+	__be32 key = parms->i_key;
+	__be16 flags = parms->i_flags;
+	int link = parms->link;
+	struct ip_tunnel *t = NULL;
+	struct hlist_head *head = ip_bucket(itn, parms);
+
+	hlist_for_each_entry_rcu(t, head, hash_node) {
+		if (local == t->parms.iph.saddr &&
+		    remote == t->parms.iph.daddr &&
+		    link == t->parms.link &&
+		    type == t->dev->type &&
+		    ip_tunnel_key_match(&t->parms, flags, key))
+			break;
+	}
+	return t;
+}
+
+static struct net_device *__ip_tunnel_create(struct net *net,
+					     const struct rtnl_link_ops *ops,
+					     struct ip_tunnel_parm *parms)
+{
+	int err;
+	struct ip_tunnel *tunnel;
+	struct net_device *dev;
+	char name[IFNAMSIZ];
+
+	err = -E2BIG;
+	if (parms->name[0]) {
+		if (!dev_valid_name(parms->name))
+			goto failed;
+		strscpy(name, parms->name, IFNAMSIZ);
+	} else {
+		if (strlen(ops->kind) > (IFNAMSIZ - 3))
+			goto failed;
+		strcpy(name, ops->kind);
+		strcat(name, "%d");
+	}
+
+	ASSERT_RTNL();
+	dev = alloc_netdev(ops->priv_size, name, NET_NAME_UNKNOWN, ops->setup);
+	if (!dev) {
+		err = -ENOMEM;
+		goto failed;
+	}
+	dev_net_set(dev, net);
+
+	dev->rtnl_link_ops = ops;
+
+	tunnel = netdev_priv(dev);
+	tunnel->parms = *parms;
+	tunnel->net = net;
+
+	err = register_netdevice(dev);
+	if (err)
+		goto failed_free;
+
+	return dev;
+
+failed_free:
+	free_netdev(dev);
+failed:
+	return ERR_PTR(err);
+}
+
+static int ip_tunnel_bind_dev(struct net_device *dev)
+{
+	struct net_device *tdev = NULL;
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	const struct iphdr *iph;
+	int hlen = LL_MAX_HEADER;
+	int mtu = ETH_DATA_LEN;
+	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
+
+	iph = &tunnel->parms.iph;
+
+	/* Guess output device to choose reasonable mtu and needed_headroom */
+	if (iph->daddr) {
+		struct flowi4 fl4;
+		struct rtable *rt;
+
+		ip_tunnel_init_flow(&fl4, iph->protocol, iph->daddr,
+				    iph->saddr, tunnel->parms.o_key,
+				    RT_TOS(iph->tos), dev_net(dev),
+				    tunnel->parms.link, tunnel->fwmark, 0, 0);
+		rt = ip_route_output_key(tunnel->net, &fl4);
+
+		if (!IS_ERR(rt)) {
+			tdev = rt->dst.dev;
+			ip_rt_put(rt);
+		}
+		if (dev->type != ARPHRD_ETHER)
+			dev->flags |= IFF_POINTOPOINT;
+
+		dst_cache_reset(&tunnel->dst_cache);
+	}
+
+	if (!tdev && tunnel->parms.link)
+		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
+
+	if (tdev) {
+		hlen = tdev->hard_header_len + tdev->needed_headroom;
+		mtu = min(tdev->mtu, IP_MAX_MTU);
+	}
+
+	dev->needed_headroom = t_hlen + hlen;
+	mtu -= t_hlen + (dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0);
+
+	if (mtu < IPV4_MIN_MTU)
+		mtu = IPV4_MIN_MTU;
+
+	return mtu;
+}
+
+static struct ip_tunnel *ip_tunnel_create(struct net *net,
+					  struct ip_tunnel_net *itn,
+					  struct ip_tunnel_parm *parms)
+{
+	struct ip_tunnel *nt;
+	struct net_device *dev;
+	int t_hlen;
+	int mtu;
+	int err;
+
+	dev = __ip_tunnel_create(net, itn->rtnl_link_ops, parms);
+	if (IS_ERR(dev))
+		return ERR_CAST(dev);
+
+	mtu = ip_tunnel_bind_dev(dev);
+	err = dev_set_mtu(dev, mtu);
+	if (err)
+		goto err_dev_set_mtu;
+
+	nt = netdev_priv(dev);
+	t_hlen = nt->hlen + sizeof(struct iphdr);
+	dev->min_mtu = ETH_MIN_MTU;
+	dev->max_mtu = IP_MAX_MTU - t_hlen;
+	if (dev->type == ARPHRD_ETHER)
+		dev->max_mtu -= dev->hard_header_len;
+
+	ip_tunnel_add(itn, nt);
+	return nt;
+
+err_dev_set_mtu:
+	unregister_netdevice(dev);
+	return ERR_PTR(err);
+}
+
+void ip_tunnel_md_udp_encap(struct sk_buff *skb, struct ip_tunnel_info *info)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	const struct udphdr *udph;
+
+	if (iph->protocol != IPPROTO_UDP)
+		return;
+
+	udph = (struct udphdr *)((__u8 *)iph + (iph->ihl << 2));
+	info->encap.sport = udph->source;
+	info->encap.dport = udph->dest;
+}
+EXPORT_SYMBOL(ip_tunnel_md_udp_encap);
+
+int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
+		  const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
+		  bool log_ecn_error)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	int err;
+
+#ifdef CONFIG_NET_IPGRE_BROADCAST
+	if (ipv4_is_multicast(iph->daddr)) {
+		DEV_STATS_INC(tunnel->dev, multicast);
+		skb->pkt_type = PACKET_BROADCAST;
+	}
+#endif
+
+	if ((!(tpi->flags&TUNNEL_CSUM) &&  (tunnel->parms.i_flags&TUNNEL_CSUM)) ||
+	     ((tpi->flags&TUNNEL_CSUM) && !(tunnel->parms.i_flags&TUNNEL_CSUM))) {
+		DEV_STATS_INC(tunnel->dev, rx_crc_errors);
+		DEV_STATS_INC(tunnel->dev, rx_errors);
+		goto drop;
+	}
+
+	if (tunnel->parms.i_flags&TUNNEL_SEQ) {
+		if (!(tpi->flags&TUNNEL_SEQ) ||
+		    (tunnel->i_seqno && (s32)(ntohl(tpi->seq) - tunnel->i_seqno) < 0)) {
+			DEV_STATS_INC(tunnel->dev, rx_fifo_errors);
+			DEV_STATS_INC(tunnel->dev, rx_errors);
+			goto drop;
+		}
+		tunnel->i_seqno = ntohl(tpi->seq) + 1;
+	}
+
+	skb_set_network_header(skb, (tunnel->dev->type == ARPHRD_ETHER) ? ETH_HLEN : 0);
+
+	err = IP_ECN_decapsulate(iph, skb);
+	if (unlikely(err)) {
+		if (log_ecn_error)
+			net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
+					&iph->saddr, iph->tos);
+		if (err > 1) {
+			DEV_STATS_INC(tunnel->dev, rx_frame_errors);
+			DEV_STATS_INC(tunnel->dev, rx_errors);
+			goto drop;
+		}
+	}
+
+	dev_sw_netstats_rx_add(tunnel->dev, skb->len);
+	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
+
+	if (tunnel->dev->type == ARPHRD_ETHER) {
+		skb->protocol = eth_type_trans(skb, tunnel->dev);
+		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
+	} else {
+		skb->dev = tunnel->dev;
+	}
+
+	if (tun_dst)
+		skb_dst_set(skb, (struct dst_entry *)tun_dst);
+
+	gro_cells_receive(&tunnel->gro_cells, skb);
+	return 0;
+
+drop:
+	if (tun_dst)
+		dst_release((struct dst_entry *)tun_dst);
+	kfree_skb(skb);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_rcv);
+
+int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *ops,
+			    unsigned int num)
+{
+	if (num >= MAX_IPTUN_ENCAP_OPS)
+		return -ERANGE;
+
+	return !cmpxchg((const struct ip_tunnel_encap_ops **)
+			&iptun_encaps[num],
+			NULL, ops) ? 0 : -1;
+}
+EXPORT_SYMBOL(ip_tunnel_encap_add_ops);
+
+int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *ops,
+			    unsigned int num)
+{
+	int ret;
+
+	if (num >= MAX_IPTUN_ENCAP_OPS)
+		return -ERANGE;
+
+	ret = (cmpxchg((const struct ip_tunnel_encap_ops **)
+		       &iptun_encaps[num],
+		       ops, NULL) == ops) ? 0 : -1;
+
+	synchronize_net();
+
+	return ret;
+}
+EXPORT_SYMBOL(ip_tunnel_encap_del_ops);
+
+int ip_tunnel_encap_setup(struct ip_tunnel *t,
+			  struct ip_tunnel_encap *ipencap)
+{
+	int hlen;
+
+	memset(&t->encap, 0, sizeof(t->encap));
+
+	hlen = ip_encap_hlen(ipencap);
+	if (hlen < 0)
+		return hlen;
+
+	t->encap.type = ipencap->type;
+	t->encap.sport = ipencap->sport;
+	t->encap.dport = ipencap->dport;
+	t->encap.flags = ipencap->flags;
+
+	t->encap_hlen = hlen;
+	t->hlen = t->encap_hlen + t->tun_hlen;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);
+
+static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
+			    struct rtable *rt, __be16 df,
+			    const struct iphdr *inner_iph,
+			    int tunnel_hlen, __be32 dst, bool md)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	int pkt_size;
+	int mtu;
+
+	tunnel_hlen = md ? tunnel_hlen : tunnel->hlen;
+	pkt_size = skb->len - tunnel_hlen;
+	pkt_size -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0;
+
+	if (df) {
+		mtu = dst_mtu(&rt->dst) - (sizeof(struct iphdr) + tunnel_hlen);
+		mtu -= dev->type == ARPHRD_ETHER ? dev->hard_header_len : 0;
+	} else {
+		mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
+	}
+
+	if (skb_valid_dst(skb))
+		skb_dst_update_pmtu_no_confirm(skb, mtu);
+
+	if (skb->protocol == htons(ETH_P_IP)) {
+		if (!skb_is_gso(skb) &&
+		    (inner_iph->frag_off & htons(IP_DF)) &&
+		    mtu < pkt_size) {
+			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
+			return -E2BIG;
+		}
+	}
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (skb->protocol == htons(ETH_P_IPV6)) {
+		struct rt6_info *rt6;
+		__be32 daddr;
+
+		rt6 = skb_valid_dst(skb) ? (struct rt6_info *)skb_dst(skb) :
+					   NULL;
+		daddr = md ? dst : tunnel->parms.iph.daddr;
+
+		if (rt6 && mtu < dst_mtu(skb_dst(skb)) &&
+			   mtu >= IPV6_MIN_MTU) {
+			if ((daddr && !ipv4_is_multicast(daddr)) ||
+			    rt6->rt6i_dst.plen == 128) {
+				rt6->rt6i_flags |= RTF_MODIFIED;
+				dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
+			}
+		}
+
+		if (!skb_is_gso(skb) && mtu >= IPV6_MIN_MTU &&
+					mtu < pkt_size) {
+			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
+			return -E2BIG;
+		}
+	}
+#endif
+	return 0;
+}
+
+void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
+		       u8 proto, int tunnel_hlen)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	u32 headroom = sizeof(struct iphdr);
+	struct ip_tunnel_info *tun_info;
+	const struct ip_tunnel_key *key;
+	const struct iphdr *inner_iph;
+	struct rtable *rt = NULL;
+	struct flowi4 fl4;
+	__be16 df = 0;
+	u8 tos, ttl;
+	bool use_cache;
+
+	tun_info = skb_tunnel_info(skb);
+	if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
+		     ip_tunnel_info_af(tun_info) != AF_INET))
+		goto tx_error;
+	key = &tun_info->key;
+	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+	inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+	tos = key->tos;
+	if (tos == 1) {
+		if (skb->protocol == htons(ETH_P_IP))
+			tos = inner_iph->tos;
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
+	}
+	ip_tunnel_init_flow(&fl4, proto, key->u.ipv4.dst, key->u.ipv4.src,
+			    tunnel_id_to_key32(key->tun_id), RT_TOS(tos),
+			    dev_net(dev), 0, skb->mark, skb_get_hash(skb),
+			    key->flow_flags);
+
+	if (!tunnel_hlen)
+		tunnel_hlen = ip_encap_hlen(&tun_info->encap);
+
+	if (ip_tunnel_encap(skb, &tun_info->encap, &proto, &fl4) < 0)
+		goto tx_error;
+
+	use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
+	if (use_cache)
+		rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl4.saddr);
+	if (!rt) {
+		rt = ip_route_output_key(tunnel->net, &fl4);
+		if (IS_ERR(rt)) {
+			DEV_STATS_INC(dev, tx_carrier_errors);
+			goto tx_error;
+		}
+		if (use_cache)
+			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
+					  fl4.saddr);
+	}
+	if (rt->dst.dev == dev) {
+		ip_rt_put(rt);
+		DEV_STATS_INC(dev, collisions);
+		goto tx_error;
+	}
+
+	if (key->tun_flags & TUNNEL_DONT_FRAGMENT)
+		df = htons(IP_DF);
+	if (tnl_update_pmtu(dev, skb, rt, df, inner_iph, tunnel_hlen,
+			    key->u.ipv4.dst, true)) {
+		ip_rt_put(rt);
+		goto tx_error;
+	}
+
+	tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
+	ttl = key->ttl;
+	if (ttl == 0) {
+		if (skb->protocol == htons(ETH_P_IP))
+			ttl = inner_iph->ttl;
+		else if (skb->protocol == htons(ETH_P_IPV6))
+			ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
+		else
+			ttl = ip4_dst_hoplimit(&rt->dst);
+	}
+
+	headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
+	if (headroom > READ_ONCE(dev->needed_headroom))
+		WRITE_ONCE(dev->needed_headroom, headroom);
+
+	if (skb_cow_head(skb, READ_ONCE(dev->needed_headroom))) {
+		ip_rt_put(rt);
+		goto tx_dropped;
+	}
+	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, proto, tos, ttl,
+		      df, !net_eq(tunnel->net, dev_net(dev)));
+	return;
+tx_error:
+	DEV_STATS_INC(dev, tx_errors);
+	goto kfree;
+tx_dropped:
+	DEV_STATS_INC(dev, tx_dropped);
+kfree:
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(ip_md_tunnel_xmit);
+
+void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
+		    const struct iphdr *tnl_params, u8 protocol)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct ip_tunnel_info *tun_info = NULL;
+	const struct iphdr *inner_iph;
+	unsigned int max_headroom;	/* The extra header space needed */
+	struct rtable *rt = NULL;		/* Route to the other host */
+	__be16 payload_protocol;
+	bool use_cache = false;
+	struct flowi4 fl4;
+	bool md = false;
+	bool connected;
+	u8 tos, ttl;
+	__be32 dst;
+	__be16 df;
+
+	inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+	connected = (tunnel->parms.iph.daddr != 0);
+	payload_protocol = skb_protocol(skb, true);
+
+	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
+	dst = tnl_params->daddr;
+	if (dst == 0) {
+		/* NBMA tunnel */
+
+		if (!skb_dst(skb)) {
+			DEV_STATS_INC(dev, tx_fifo_errors);
+			goto tx_error;
+		}
+
+		tun_info = skb_tunnel_info(skb);
+		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX) &&
+		    ip_tunnel_info_af(tun_info) == AF_INET &&
+		    tun_info->key.u.ipv4.dst) {
+			dst = tun_info->key.u.ipv4.dst;
+			md = true;
+			connected = true;
+		} else if (payload_protocol == htons(ETH_P_IP)) {
+			rt = skb_rtable(skb);
+			dst = rt_nexthop(rt, inner_iph->daddr);
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (payload_protocol == htons(ETH_P_IPV6)) {
+			const struct in6_addr *addr6;
+			struct neighbour *neigh;
+			bool do_tx_error_icmp;
+			int addr_type;
+
+			neigh = dst_neigh_lookup(skb_dst(skb),
+						 &ipv6_hdr(skb)->daddr);
+			if (!neigh)
+				goto tx_error;
+
+			addr6 = (const struct in6_addr *)&neigh->primary_key;
+			addr_type = ipv6_addr_type(addr6);
+
+			if (addr_type == IPV6_ADDR_ANY) {
+				addr6 = &ipv6_hdr(skb)->daddr;
+				addr_type = ipv6_addr_type(addr6);
+			}
+
+			if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
+				do_tx_error_icmp = true;
+			else {
+				do_tx_error_icmp = false;
+				dst = addr6->s6_addr32[3];
+			}
+			neigh_release(neigh);
+			if (do_tx_error_icmp)
+				goto tx_error_icmp;
+		}
+#endif
+		else
+			goto tx_error;
+
+		if (!md)
+			connected = false;
+	}
+
+	tos = tnl_params->tos;
+	if (tos & 0x1) {
+		tos &= ~0x1;
+		if (payload_protocol == htons(ETH_P_IP)) {
+			tos = inner_iph->tos;
+			connected = false;
+		} else if (payload_protocol == htons(ETH_P_IPV6)) {
+			tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
+			connected = false;
+		}
+	}
+
+	ip_tunnel_init_flow(&fl4, protocol, dst, tnl_params->saddr,
+			    tunnel->parms.o_key, RT_TOS(tos),
+			    dev_net(dev), tunnel->parms.link,
+			    tunnel->fwmark, skb_get_hash(skb), 0);
+
+	if (ip_tunnel_encap(skb, &tunnel->encap, &protocol, &fl4) < 0)
+		goto tx_error;
+
+	if (connected && md) {
+		use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
+		if (use_cache)
+			rt = dst_cache_get_ip4(&tun_info->dst_cache,
+					       &fl4.saddr);
+	} else {
+		rt = connected ? dst_cache_get_ip4(&tunnel->dst_cache,
+						&fl4.saddr) : NULL;
+	}
+
+	if (!rt) {
+		rt = ip_route_output_key(tunnel->net, &fl4);
+
+		if (IS_ERR(rt)) {
+			DEV_STATS_INC(dev, tx_carrier_errors);
+			goto tx_error;
+		}
+		if (use_cache)
+			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
+					  fl4.saddr);
+		else if (!md && connected)
+			dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst,
+					  fl4.saddr);
+	}
+
+	if (rt->dst.dev == dev) {
+		ip_rt_put(rt);
+		DEV_STATS_INC(dev, collisions);
+		goto tx_error;
+	}
+
+	df = tnl_params->frag_off;
+	if (payload_protocol == htons(ETH_P_IP) && !tunnel->ignore_df)
+		df |= (inner_iph->frag_off & htons(IP_DF));
+
+	if (tnl_update_pmtu(dev, skb, rt, df, inner_iph, 0, 0, false)) {
+		ip_rt_put(rt);
+		goto tx_error;
+	}
+
+	if (tunnel->err_count > 0) {
+		if (time_before(jiffies,
+				tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
+			tunnel->err_count--;
+
+			dst_link_failure(skb);
+		} else
+			tunnel->err_count = 0;
+	}
+
+	tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
+	ttl = tnl_params->ttl;
+	if (ttl == 0) {
+		if (payload_protocol == htons(ETH_P_IP))
+			ttl = inner_iph->ttl;
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (payload_protocol == htons(ETH_P_IPV6))
+			ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
+#endif
+		else
+			ttl = ip4_dst_hoplimit(&rt->dst);
+	}
+
+	max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
+			+ rt->dst.header_len + ip_encap_hlen(&tunnel->encap);
+	if (max_headroom > READ_ONCE(dev->needed_headroom))
+		WRITE_ONCE(dev->needed_headroom, max_headroom);
+
+	if (skb_cow_head(skb, READ_ONCE(dev->needed_headroom))) {
+		ip_rt_put(rt);
+		DEV_STATS_INC(dev, tx_dropped);
+		kfree_skb(skb);
+		return;
+	}
+
+	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
+		      df, !net_eq(tunnel->net, dev_net(dev)));
+	return;
+
+#if IS_ENABLED(CONFIG_IPV6)
+tx_error_icmp:
+	dst_link_failure(skb);
+#endif
+tx_error:
+	DEV_STATS_INC(dev, tx_errors);
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_xmit);
+
+static void ip_tunnel_update(struct ip_tunnel_net *itn,
+			     struct ip_tunnel *t,
+			     struct net_device *dev,
+			     struct ip_tunnel_parm *p,
+			     bool set_mtu,
+			     __u32 fwmark)
+{
+	ip_tunnel_del(itn, t);
+	t->parms.iph.saddr = p->iph.saddr;
+	t->parms.iph.daddr = p->iph.daddr;
+	t->parms.i_key = p->i_key;
+	t->parms.o_key = p->o_key;
+	if (dev->type != ARPHRD_ETHER) {
+		__dev_addr_set(dev, &p->iph.saddr, 4);
+		memcpy(dev->broadcast, &p->iph.daddr, 4);
+	}
+	ip_tunnel_add(itn, t);
+
+	t->parms.iph.ttl = p->iph.ttl;
+	t->parms.iph.tos = p->iph.tos;
+	t->parms.iph.frag_off = p->iph.frag_off;
+
+	if (t->parms.link != p->link || t->fwmark != fwmark) {
+		int mtu;
+
+		t->parms.link = p->link;
+		t->fwmark = fwmark;
+		mtu = ip_tunnel_bind_dev(dev);
+		if (set_mtu)
+			dev->mtu = mtu;
+	}
+	dst_cache_reset(&t->dst_cache);
+	netdev_state_change(dev);
+}
+
+int ip_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
+{
+	int err = 0;
+	struct ip_tunnel *t = netdev_priv(dev);
+	struct net *net = t->net;
+	struct ip_tunnel_net *itn = net_generic(net, t->ip_tnl_net_id);
+
+	switch (cmd) {
+	case SIOCGETTUNNEL:
+		if (dev == itn->fb_tunnel_dev) {
+			t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
+			if (!t)
+				t = netdev_priv(dev);
+		}
+		memcpy(p, &t->parms, sizeof(*p));
+		break;
+
+	case SIOCADDTUNNEL:
+	case SIOCCHGTUNNEL:
+		err = -EPERM;
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+			goto done;
+		if (p->iph.ttl)
+			p->iph.frag_off |= htons(IP_DF);
+		if (!(p->i_flags & VTI_ISVTI)) {
+			if (!(p->i_flags & TUNNEL_KEY))
+				p->i_key = 0;
+			if (!(p->o_flags & TUNNEL_KEY))
+				p->o_key = 0;
+		}
+
+		t = ip_tunnel_find(itn, p, itn->type);
+
+		if (cmd == SIOCADDTUNNEL) {
+			if (!t) {
+				t = ip_tunnel_create(net, itn, p);
+				err = PTR_ERR_OR_ZERO(t);
+				break;
+			}
+
+			err = -EEXIST;
+			break;
+		}
+		if (dev != itn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
+			if (t) {
+				if (t->dev != dev) {
+					err = -EEXIST;
+					break;
+				}
+			} else {
+				unsigned int nflags = 0;
+
+				if (ipv4_is_multicast(p->iph.daddr))
+					nflags = IFF_BROADCAST;
+				else if (p->iph.daddr)
+					nflags = IFF_POINTOPOINT;
+
+				if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
+					err = -EINVAL;
+					break;
+				}
+
+				t = netdev_priv(dev);
+			}
+		}
+
+		if (t) {
+			err = 0;
+			ip_tunnel_update(itn, t, dev, p, true, 0);
+		} else {
+			err = -ENOENT;
+		}
+		break;
+
+	case SIOCDELTUNNEL:
+		err = -EPERM;
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+			goto done;
+
+		if (dev == itn->fb_tunnel_dev) {
+			err = -ENOENT;
+			t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
+			if (!t)
+				goto done;
+			err = -EPERM;
+			if (t == netdev_priv(itn->fb_tunnel_dev))
+				goto done;
+			dev = t->dev;
+		}
+		unregister_netdevice(dev);
+		err = 0;
+		break;
+
+	default:
+		err = -EINVAL;
+	}
+
+done:
+	return err;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_ctl);
+
+int ip_tunnel_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
+			     void __user *data, int cmd)
+{
+	struct ip_tunnel_parm p;
+	int err;
+
+	if (copy_from_user(&p, data, sizeof(p)))
+		return -EFAULT;
+	err = dev->netdev_ops->ndo_tunnel_ctl(dev, &p, cmd);
+	if (!err && copy_to_user(data, &p, sizeof(p)))
+		return -EFAULT;
+	return err;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_siocdevprivate);
+
+int __ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	int t_hlen = tunnel->hlen + sizeof(struct iphdr);
+	int max_mtu = IP_MAX_MTU - t_hlen;
+
+	if (dev->type == ARPHRD_ETHER)
+		max_mtu -= dev->hard_header_len;
+
+	if (new_mtu < ETH_MIN_MTU)
+		return -EINVAL;
+
+	if (new_mtu > max_mtu) {
+		if (strict)
+			return -EINVAL;
+
+		new_mtu = max_mtu;
+	}
+
+	dev->mtu = new_mtu;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__ip_tunnel_change_mtu);
+
+int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
+{
+	return __ip_tunnel_change_mtu(dev, new_mtu, true);
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_change_mtu);
+
+static void ip_tunnel_dev_free(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+
+	gro_cells_destroy(&tunnel->gro_cells);
+	dst_cache_destroy(&tunnel->dst_cache);
+	free_percpu(dev->tstats);
+}
+
+void ip_tunnel_dellink(struct net_device *dev, struct list_head *head)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct ip_tunnel_net *itn;
+
+	itn = net_generic(tunnel->net, tunnel->ip_tnl_net_id);
+
+	if (itn->fb_tunnel_dev != dev) {
+		ip_tunnel_del(itn, netdev_priv(dev));
+		unregister_netdevice_queue(dev, head);
+	}
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_dellink);
+
+struct net *ip_tunnel_get_link_net(const struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+
+	return tunnel->net;
+}
+EXPORT_SYMBOL(ip_tunnel_get_link_net);
+
+int ip_tunnel_get_iflink(const struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+
+	return tunnel->parms.link;
+}
+EXPORT_SYMBOL(ip_tunnel_get_iflink);
+
+int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
+				  struct rtnl_link_ops *ops, char *devname)
+{
+	struct ip_tunnel_net *itn = net_generic(net, ip_tnl_net_id);
+	struct ip_tunnel_parm parms;
+	unsigned int i;
+
+	itn->rtnl_link_ops = ops;
+	for (i = 0; i < IP_TNL_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&itn->tunnels[i]);
+
+	if (!ops || !net_has_fallback_tunnels(net)) {
+		struct ip_tunnel_net *it_init_net;
+
+		it_init_net = net_generic(&init_net, ip_tnl_net_id);
+		itn->type = it_init_net->type;
+		itn->fb_tunnel_dev = NULL;
+		return 0;
+	}
+
+	memset(&parms, 0, sizeof(parms));
+	if (devname)
+		strscpy(parms.name, devname, IFNAMSIZ);
+
+	rtnl_lock();
+	itn->fb_tunnel_dev = __ip_tunnel_create(net, ops, &parms);
+	/* FB netdevice is special: we have one, and only one per netns.
+	 * Allowing to move it to another netns is clearly unsafe.
+	 */
+	if (!IS_ERR(itn->fb_tunnel_dev)) {
+		itn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
+		itn->fb_tunnel_dev->mtu = ip_tunnel_bind_dev(itn->fb_tunnel_dev);
+		ip_tunnel_add(itn, netdev_priv(itn->fb_tunnel_dev));
+		itn->type = itn->fb_tunnel_dev->type;
+	}
+	rtnl_unlock();
+
+	return PTR_ERR_OR_ZERO(itn->fb_tunnel_dev);
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_init_net);
+
+static void ip_tunnel_destroy(struct net *net, struct ip_tunnel_net *itn,
+			      struct list_head *head,
+			      struct rtnl_link_ops *ops)
+{
+	struct net_device *dev, *aux;
+	int h;
+
+	for_each_netdev_safe(net, dev, aux)
+		if (dev->rtnl_link_ops == ops)
+			unregister_netdevice_queue(dev, head);
+
+	for (h = 0; h < IP_TNL_HASH_SIZE; h++) {
+		struct ip_tunnel *t;
+		struct hlist_node *n;
+		struct hlist_head *thead = &itn->tunnels[h];
+
+		hlist_for_each_entry_safe(t, n, thead, hash_node)
+			/* If dev is in the same netns, it has already
+			 * been added to the list by the previous loop.
+			 */
+			if (!net_eq(dev_net(t->dev), net))
+				unregister_netdevice_queue(t->dev, head);
+	}
+}
+
+void ip_tunnel_delete_nets(struct list_head *net_list, unsigned int id,
+			   struct rtnl_link_ops *ops)
+{
+	struct ip_tunnel_net *itn;
+	struct net *net;
+	LIST_HEAD(list);
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list) {
+		itn = net_generic(net, id);
+		ip_tunnel_destroy(net, itn, &list, ops);
+	}
+	unregister_netdevice_many(&list);
+	rtnl_unlock();
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_delete_nets);
+
+int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
+		      struct ip_tunnel_parm *p, __u32 fwmark)
+{
+	struct ip_tunnel *nt;
+	struct net *net = dev_net(dev);
+	struct ip_tunnel_net *itn;
+	int mtu;
+	int err;
+
+	nt = netdev_priv(dev);
+	itn = net_generic(net, nt->ip_tnl_net_id);
+
+	if (nt->collect_md) {
+		if (rtnl_dereference(itn->collect_md_tun))
+			return -EEXIST;
+	} else {
+		if (ip_tunnel_find(itn, p, dev->type))
+			return -EEXIST;
+	}
+
+	nt->net = net;
+	nt->parms = *p;
+	nt->fwmark = fwmark;
+	err = register_netdevice(dev);
+	if (err)
+		goto err_register_netdevice;
+
+	if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
+		eth_hw_addr_random(dev);
+
+	mtu = ip_tunnel_bind_dev(dev);
+	if (tb[IFLA_MTU]) {
+		unsigned int max = IP_MAX_MTU - (nt->hlen + sizeof(struct iphdr));
+
+		if (dev->type == ARPHRD_ETHER)
+			max -= dev->hard_header_len;
+
+		mtu = clamp(dev->mtu, (unsigned int)ETH_MIN_MTU, max);
+	}
+
+	err = dev_set_mtu(dev, mtu);
+	if (err)
+		goto err_dev_set_mtu;
+
+	ip_tunnel_add(itn, nt);
+	return 0;
+
+err_dev_set_mtu:
+	unregister_netdevice(dev);
+err_register_netdevice:
+	return err;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_newlink);
+
+int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
+			 struct ip_tunnel_parm *p, __u32 fwmark)
+{
+	struct ip_tunnel *t;
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct net *net = tunnel->net;
+	struct ip_tunnel_net *itn = net_generic(net, tunnel->ip_tnl_net_id);
+
+	if (dev == itn->fb_tunnel_dev)
+		return -EINVAL;
+
+	t = ip_tunnel_find(itn, p, dev->type);
+
+	if (t) {
+		if (t->dev != dev)
+			return -EEXIST;
+	} else {
+		t = tunnel;
+
+		if (dev->type != ARPHRD_ETHER) {
+			unsigned int nflags = 0;
+
+			if (ipv4_is_multicast(p->iph.daddr))
+				nflags = IFF_BROADCAST;
+			else if (p->iph.daddr)
+				nflags = IFF_POINTOPOINT;
+
+			if ((dev->flags ^ nflags) &
+			    (IFF_POINTOPOINT | IFF_BROADCAST))
+				return -EINVAL;
+		}
+	}
+
+	ip_tunnel_update(itn, t, dev, p, !tb[IFLA_MTU], fwmark);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_changelink);
+
+int ip_tunnel_init(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct iphdr *iph = &tunnel->parms.iph;
+	int err;
+
+	dev->needs_free_netdev = true;
+	dev->priv_destructor = ip_tunnel_dev_free;
+	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+
+	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
+	if (err) {
+		free_percpu(dev->tstats);
+		return err;
+	}
+
+	err = gro_cells_init(&tunnel->gro_cells, dev);
+	if (err) {
+		dst_cache_destroy(&tunnel->dst_cache);
+		free_percpu(dev->tstats);
+		return err;
+	}
+
+	tunnel->dev = dev;
+	tunnel->net = dev_net(dev);
+	strcpy(tunnel->parms.name, dev->name);
+	iph->version		= 4;
+	iph->ihl		= 5;
+
+	if (tunnel->collect_md)
+		netif_keep_dst(dev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_init);
+
+void ip_tunnel_uninit(struct net_device *dev)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	struct net *net = tunnel->net;
+	struct ip_tunnel_net *itn;
+
+	itn = net_generic(net, tunnel->ip_tnl_net_id);
+	ip_tunnel_del(itn, netdev_priv(dev));
+	if (itn->fb_tunnel_dev == dev)
+		WRITE_ONCE(itn->fb_tunnel_dev, NULL);
+
+	dst_cache_reset(&tunnel->dst_cache);
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_uninit);
+
+/* Do least required initialization, rest of init is done in tunnel_init call */
+void ip_tunnel_setup(struct net_device *dev, unsigned int net_id)
+{
+	struct ip_tunnel *tunnel = netdev_priv(dev);
+	tunnel->ip_tnl_net_id = net_id;
+}
+EXPORT_SYMBOL_GPL(ip_tunnel_setup);
+
+MODULE_LICENSE("GPL");