Initial import

1 files changed, 999 insertions, 0 deletions

diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
new file mode 100644
index 000000000..34968cd5c
--- /dev/null
+++ b/net/ipv4/fou.c
@@ -0,0 +1,999 @@
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <net/genetlink.h>
+#include <net/gue.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/udp.h>
+#include <net/udp_tunnel.h>
+#include <net/xfrm.h>
+#include <uapi/linux/fou.h>
+#include <uapi/linux/genetlink.h>
+
+struct fou {
+	struct socket *sock;
+	u8 protocol;
+	u8 flags;
+	__be16 port;
+	u16 type;
+	struct udp_offload udp_offloads;
+	struct list_head list;
+};
+
+#define FOU_F_REMCSUM_NOPARTIAL BIT(0)
+
+struct fou_cfg {
+	u16 type;
+	u8 protocol;
+	u8 flags;
+	struct udp_port_cfg udp_config;
+};
+
+static unsigned int fou_net_id;
+
+struct fou_net {
+	struct list_head fou_list;
+	struct mutex fou_lock;
+};
+
+static inline struct fou *fou_from_sock(struct sock *sk)
+{
+	return sk->sk_user_data;
+}
+
+static void fou_recv_pull(struct sk_buff *skb, size_t len)
+{
+	struct iphdr *iph = ip_hdr(skb);
+
+	/* Remove 'len' bytes from the packet (UDP header and
+	 * FOU header if present).
+	 */
+	iph->tot_len = htons(ntohs(iph->tot_len) - len);
+	__skb_pull(skb, len);
+	skb_postpull_rcsum(skb, udp_hdr(skb), len);
+	skb_reset_transport_header(skb);
+}
+
+static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct fou *fou = fou_from_sock(sk);
+
+	if (!fou)
+		return 1;
+
+	fou_recv_pull(skb, sizeof(struct udphdr));
+
+	return -fou->protocol;
+}
+
+static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
+				  void *data, size_t hdrlen, u8 ipproto,
+				  bool nopartial)
+{
+	__be16 *pd = data;
+	size_t start = ntohs(pd[0]);
+	size_t offset = ntohs(pd[1]);
+	size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
+
+	if (!pskb_may_pull(skb, plen))
+		return NULL;
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
+
+	skb_remcsum_process(skb, (void *)guehdr + hdrlen,
+			    start, offset, nopartial);
+
+	return guehdr;
+}
+
+static int gue_control_message(struct sk_buff *skb, struct guehdr *guehdr)
+{
+	/* No support yet */
+	kfree_skb(skb);
+	return 0;
+}
+
+static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
+{
+	struct fou *fou = fou_from_sock(sk);
+	size_t len, optlen, hdrlen;
+	struct guehdr *guehdr;
+	void *data;
+	u16 doffset = 0;
+
+	if (!fou)
+		return 1;
+
+	len = sizeof(struct udphdr) + sizeof(struct guehdr);
+	if (!pskb_may_pull(skb, len))
+		goto drop;
+
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
+
+	optlen = guehdr->hlen << 2;
+	len += optlen;
+
+	if (!pskb_may_pull(skb, len))
+		goto drop;
+
+	/* guehdr may change after pull */
+	guehdr = (struct guehdr *)&udp_hdr(skb)[1];
+
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	if (guehdr->version != 0 || validate_gue_flags(guehdr, optlen))
+		goto drop;
+
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);
+
+	/* Pull csum through the guehdr now . This can be used if
+	 * there is a remote checksum offload.
+	 */
+	skb_postpull_rcsum(skb, udp_hdr(skb), len);
+
+	data = &guehdr[1];
+
+	if (guehdr->flags & GUE_FLAG_PRIV) {
+		__be32 flags = *(__be32 *)(data + doffset);
+
+		doffset += GUE_LEN_PRIV;
+
+		if (flags & GUE_PFLAG_REMCSUM) {
+			guehdr = gue_remcsum(skb, guehdr, data + doffset,
+					     hdrlen, guehdr->proto_ctype,
+					     !!(fou->flags &
+						FOU_F_REMCSUM_NOPARTIAL));
+			if (!guehdr)
+				goto drop;
+
+			data = &guehdr[1];
+
+			doffset += GUE_PLEN_REMCSUM;
+		}
+	}
+
+	if (unlikely(guehdr->control))
+		return gue_control_message(skb, guehdr);
+
+	__skb_pull(skb, sizeof(struct udphdr) + hdrlen);
+	skb_reset_transport_header(skb);
+
+	return -guehdr->proto_ctype;
+
+drop:
+	kfree_skb(skb);
+	return 0;
+}
+
+static struct sk_buff **fou_gro_receive(struct sk_buff **head,
+					struct sk_buff *skb,
+					struct udp_offload *uoff)
+{
+	const struct net_offload *ops;
+	struct sk_buff **pp = NULL;
+	u8 proto = NAPI_GRO_CB(skb)->proto;
+	const struct net_offload **offloads;
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[proto]);
+	if (!ops || !ops->callbacks.gro_receive)
+		goto out_unlock;
+
+	pp = ops->callbacks.gro_receive(head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return pp;
+}
+
+static int fou_gro_complete(struct sk_buff *skb, int nhoff,
+			    struct udp_offload *uoff)
+{
+	const struct net_offload *ops;
+	u8 proto = NAPI_GRO_CB(skb)->proto;
+	int err = -ENOSYS;
+	const struct net_offload **offloads;
+
+	udp_tunnel_gro_complete(skb, nhoff);
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[proto]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+		goto out_unlock;
+
+	err = ops->callbacks.gro_complete(skb, nhoff);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return err;
+}
+
+static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
+				      struct guehdr *guehdr, void *data,
+				      size_t hdrlen, u8 ipproto,
+				      struct gro_remcsum *grc, bool nopartial)
+{
+	__be16 *pd = data;
+	size_t start = ntohs(pd[0]);
+	size_t offset = ntohs(pd[1]);
+	size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start);
+
+	if (skb->remcsum_offload)
+		return NULL;
+
+	if (!NAPI_GRO_CB(skb)->csum_valid)
+		return NULL;
+
+	/* Pull checksum that will be written */
+	if (skb_gro_header_hard(skb, off + plen)) {
+		guehdr = skb_gro_header_slow(skb, off + plen, off);
+		if (!guehdr)
+			return NULL;
+	}
+
+	skb_gro_remcsum_process(skb, (void *)guehdr + hdrlen,
+				start, offset, grc, nopartial);
+
+	skb->remcsum_offload = 1;
+
+	return guehdr;
+}
+
+static struct sk_buff **gue_gro_receive(struct sk_buff **head,
+					struct sk_buff *skb,
+					struct udp_offload *uoff)
+{
+	const struct net_offload **offloads;
+	const struct net_offload *ops;
+	struct sk_buff **pp = NULL;
+	struct sk_buff *p;
+	struct guehdr *guehdr;
+	size_t len, optlen, hdrlen, off;
+	void *data;
+	u16 doffset = 0;
+	int flush = 1;
+	struct fou *fou = container_of(uoff, struct fou, udp_offloads);
+	struct gro_remcsum grc;
+
+	skb_gro_remcsum_init(&grc);
+
+	off = skb_gro_offset(skb);
+	len = off + sizeof(*guehdr);
+
+	guehdr = skb_gro_header_fast(skb, off);
+	if (skb_gro_header_hard(skb, len)) {
+		guehdr = skb_gro_header_slow(skb, len, off);
+		if (unlikely(!guehdr))
+			goto out;
+	}
+
+	optlen = guehdr->hlen << 2;
+	len += optlen;
+
+	if (skb_gro_header_hard(skb, len)) {
+		guehdr = skb_gro_header_slow(skb, len, off);
+		if (unlikely(!guehdr))
+			goto out;
+	}
+
+	if (unlikely(guehdr->control) || guehdr->version != 0 ||
+	    validate_gue_flags(guehdr, optlen))
+		goto out;
+
+	hdrlen = sizeof(*guehdr) + optlen;
+
+	/* Adjust NAPI_GRO_CB(skb)->csum to account for guehdr,
+	 * this is needed if there is a remote checkcsum offload.
+	 */
+	skb_gro_postpull_rcsum(skb, guehdr, hdrlen);
+
+	data = &guehdr[1];
+
+	if (guehdr->flags & GUE_FLAG_PRIV) {
+		__be32 flags = *(__be32 *)(data + doffset);
+
+		doffset += GUE_LEN_PRIV;
+
+		if (flags & GUE_PFLAG_REMCSUM) {
+			guehdr = gue_gro_remcsum(skb, off, guehdr,
+						 data + doffset, hdrlen,
+						 guehdr->proto_ctype, &grc,
+						 !!(fou->flags &
+						    FOU_F_REMCSUM_NOPARTIAL));
+			if (!guehdr)
+				goto out;
+
+			data = &guehdr[1];
+
+			doffset += GUE_PLEN_REMCSUM;
+		}
+	}
+
+	skb_gro_pull(skb, hdrlen);
+
+	flush = 0;
+
+	for (p = *head; p; p = p->next) {
+		const struct guehdr *guehdr2;
+
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		guehdr2 = (struct guehdr *)(p->data + off);
+
+		/* Compare base GUE header to be equal (covers
+		 * hlen, version, proto_ctype, and flags.
+		 */
+		if (guehdr->word != guehdr2->word) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+
+		/* Compare optional fields are the same. */
+		if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
+					   guehdr->hlen << 2)) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+	}
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[guehdr->proto_ctype]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_receive))
+		goto out_unlock;
+
+	pp = ops->callbacks.gro_receive(head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+out:
+	NAPI_GRO_CB(skb)->flush |= flush;
+	skb_gro_remcsum_cleanup(skb, &grc);
+
+	return pp;
+}
+
+static int gue_gro_complete(struct sk_buff *skb, int nhoff,
+			    struct udp_offload *uoff)
+{
+	const struct net_offload **offloads;
+	struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
+	const struct net_offload *ops;
+	unsigned int guehlen;
+	u8 proto;
+	int err = -ENOENT;
+
+	proto = guehdr->proto_ctype;
+
+	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);
+
+	rcu_read_lock();
+	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
+	ops = rcu_dereference(offloads[proto]);
+	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+		goto out_unlock;
+
+	err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
+
+out_unlock:
+	rcu_read_unlock();
+	return err;
+}
+
+static int fou_add_to_port_list(struct net *net, struct fou *fou)
+{
+	struct fou_net *fn = net_generic(net, fou_net_id);
+	struct fou *fout;
+
+	mutex_lock(&fn->fou_lock);
+	list_for_each_entry(fout, &fn->fou_list, list) {
+		if (fou->port == fout->port) {
+			mutex_unlock(&fn->fou_lock);
+			return -EALREADY;
+		}
+	}
+
+	list_add(&fou->list, &fn->fou_list);
+	mutex_unlock(&fn->fou_lock);
+
+	return 0;
+}
+
+static void fou_release(struct fou *fou)
+{
+	struct socket *sock = fou->sock;
+	struct sock *sk = sock->sk;
+
+	if (sk->sk_family == AF_INET)
+		udp_del_offload(&fou->udp_offloads);
+	list_del(&fou->list);
+	udp_tunnel_sock_release(sock);
+
+	kfree(fou);
+}
+
+static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+	udp_sk(sk)->encap_rcv = fou_udp_recv;
+	fou->protocol = cfg->protocol;
+	fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
+	fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
+	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+	fou->udp_offloads.ipproto = cfg->protocol;
+
+	return 0;
+}
+
+static int gue_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
+{
+	udp_sk(sk)->encap_rcv = gue_udp_recv;
+	fou->udp_offloads.callbacks.gro_receive = gue_gro_receive;
+	fou->udp_offloads.callbacks.gro_complete = gue_gro_complete;
+	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
+
+	return 0;
+}
+
+static int fou_create(struct net *net, struct fou_cfg *cfg,
+		      struct socket **sockp)
+{
+	struct socket *sock = NULL;
+	struct fou *fou = NULL;
+	struct sock *sk;
+	int err;
+
+	/* Open UDP socket */
+	err = udp_sock_create(net, &cfg->udp_config, &sock);
+	if (err < 0)
+		goto error;
+
+	/* Allocate FOU port structure */
+	fou = kzalloc(sizeof(*fou), GFP_KERNEL);
+	if (!fou) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	sk = sock->sk;
+
+	fou->flags = cfg->flags;
+	fou->port = cfg->udp_config.local_udp_port;
+
+	/* Initial for fou type */
+	switch (cfg->type) {
+	case FOU_ENCAP_DIRECT:
+		err = fou_encap_init(sk, fou, cfg);
+		if (err)
+			goto error;
+		break;
+	case FOU_ENCAP_GUE:
+		err = gue_encap_init(sk, fou, cfg);
+		if (err)
+			goto error;
+		break;
+	default:
+		err = -EINVAL;
+		goto error;
+	}
+
+	fou->type = cfg->type;
+
+	udp_sk(sk)->encap_type = 1;
+	udp_encap_enable();
+
+	sk->sk_user_data = fou;
+	fou->sock = sock;
+
+	inet_inc_convert_csum(sk);
+
+	sk->sk_allocation = GFP_ATOMIC;
+
+	if (cfg->udp_config.family == AF_INET) {
+		err = udp_add_offload(&fou->udp_offloads);
+		if (err)
+			goto error;
+	}
+
+	err = fou_add_to_port_list(net, fou);
+	if (err)
+		goto error;
+
+	if (sockp)
+		*sockp = sock;
+
+	return 0;
+
+error:
+	kfree(fou);
+	if (sock)
+		udp_tunnel_sock_release(sock);
+
+	return err;
+}
+
+static int fou_destroy(struct net *net, struct fou_cfg *cfg)
+{
+	struct fou_net *fn = net_generic(net, fou_net_id);
+	__be16 port = cfg->udp_config.local_udp_port;
+	int err = -EINVAL;
+	struct fou *fou;
+
+	mutex_lock(&fn->fou_lock);
+	list_for_each_entry(fou, &fn->fou_list, list) {
+		if (fou->port == port) {
+			fou_release(fou);
+			err = 0;
+			break;
+		}
+	}
+	mutex_unlock(&fn->fou_lock);
+
+	return err;
+}
+
+static struct genl_family fou_nl_family = {
+	.id		= GENL_ID_GENERATE,
+	.hdrsize	= 0,
+	.name		= FOU_GENL_NAME,
+	.version	= FOU_GENL_VERSION,
+	.maxattr	= FOU_ATTR_MAX,
+	.netnsok	= true,
+};
+
+static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
+	[FOU_ATTR_PORT] = { .type = NLA_U16, },
+	[FOU_ATTR_AF] = { .type = NLA_U8, },
+	[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
+	[FOU_ATTR_TYPE] = { .type = NLA_U8, },
+	[FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG, },
+};
+
+static int parse_nl_config(struct genl_info *info,
+			   struct fou_cfg *cfg)
+{
+	memset(cfg, 0, sizeof(*cfg));
+
+	cfg->udp_config.family = AF_INET;
+
+	if (info->attrs[FOU_ATTR_AF]) {
+		u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]);
+
+		if (family != AF_INET && family != AF_INET6)
+			return -EINVAL;
+
+		cfg->udp_config.family = family;
+	}
+
+	if (info->attrs[FOU_ATTR_PORT]) {
+		__be16 port = nla_get_be16(info->attrs[FOU_ATTR_PORT]);
+
+		cfg->udp_config.local_udp_port = port;
+	}
+
+	if (info->attrs[FOU_ATTR_IPPROTO])
+		cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);
+
+	if (info->attrs[FOU_ATTR_TYPE])
+		cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);
+
+	if (info->attrs[FOU_ATTR_REMCSUM_NOPARTIAL])
+		cfg->flags |= FOU_F_REMCSUM_NOPARTIAL;
+
+	return 0;
+}
+
+static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = genl_info_net(info);
+	struct fou_cfg cfg;
+	int err;
+
+	err = parse_nl_config(info, &cfg);
+	if (err)
+		return err;
+
+	return fou_create(net, &cfg, NULL);
+}
+
+static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = genl_info_net(info);
+	struct fou_cfg cfg;
+	int err;
+
+	err = parse_nl_config(info, &cfg);
+	if (err)
+		return err;
+
+	return fou_destroy(net, &cfg);
+}
+
+static int fou_fill_info(struct fou *fou, struct sk_buff *msg)
+{
+	if (nla_put_u8(msg, FOU_ATTR_AF, fou->sock->sk->sk_family) ||
+	    nla_put_be16(msg, FOU_ATTR_PORT, fou->port) ||
+	    nla_put_u8(msg, FOU_ATTR_IPPROTO, fou->protocol) ||
+	    nla_put_u8(msg, FOU_ATTR_TYPE, fou->type))
+		return -1;
+
+	if (fou->flags & FOU_F_REMCSUM_NOPARTIAL)
+		if (nla_put_flag(msg, FOU_ATTR_REMCSUM_NOPARTIAL))
+			return -1;
+	return 0;
+}
+
+static int fou_dump_info(struct fou *fou, u32 portid, u32 seq,
+			 u32 flags, struct sk_buff *skb, u8 cmd)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(skb, portid, seq, &fou_nl_family, flags, cmd);
+	if (!hdr)
+		return -ENOMEM;
+
+	if (fou_fill_info(fou, skb) < 0)
+		goto nla_put_failure;
+
+	genlmsg_end(skb, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+static int fou_nl_cmd_get_port(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = genl_info_net(info);
+	struct fou_net *fn = net_generic(net, fou_net_id);
+	struct sk_buff *msg;
+	struct fou_cfg cfg;
+	struct fou *fout;
+	__be16 port;
+	int ret;
+
+	ret = parse_nl_config(info, &cfg);
+	if (ret)
+		return ret;
+	port = cfg.udp_config.local_udp_port;
+	if (port == 0)
+		return -EINVAL;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	ret = -ESRCH;
+	mutex_lock(&fn->fou_lock);
+	list_for_each_entry(fout, &fn->fou_list, list) {
+		if (port == fout->port) {
+			ret = fou_dump_info(fout, info->snd_portid,
+					    info->snd_seq, 0, msg,
+					    info->genlhdr->cmd);
+			break;
+		}
+	}
+	mutex_unlock(&fn->fou_lock);
+	if (ret < 0)
+		goto out_free;
+
+	return genlmsg_reply(msg, info);
+
+out_free:
+	nlmsg_free(msg);
+	return ret;
+}
+
+static int fou_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct fou_net *fn = net_generic(net, fou_net_id);
+	struct fou *fout;
+	int idx = 0, ret;
+
+	mutex_lock(&fn->fou_lock);
+	list_for_each_entry(fout, &fn->fou_list, list) {
+		if (idx++ < cb->args[0])
+			continue;
+		ret = fou_dump_info(fout, NETLINK_CB(cb->skb).portid,
+				    cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				    skb, FOU_CMD_GET);
+		if (ret)
+			break;
+	}
+	mutex_unlock(&fn->fou_lock);
+
+	cb->args[0] = idx;
+	return skb->len;
+}
+
+static const struct genl_ops fou_nl_ops[] = {
+	{
+		.cmd = FOU_CMD_ADD,
+		.doit = fou_nl_cmd_add_port,
+		.policy = fou_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = FOU_CMD_DEL,
+		.doit = fou_nl_cmd_rm_port,
+		.policy = fou_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = FOU_CMD_GET,
+		.doit = fou_nl_cmd_get_port,
+		.dumpit = fou_nl_dump,
+		.policy = fou_nl_policy,
+	},
+};
+
+size_t fou_encap_hlen(struct ip_tunnel_encap *e)
+{
+	return sizeof(struct udphdr);
+}
+EXPORT_SYMBOL(fou_encap_hlen);
+
+size_t gue_encap_hlen(struct ip_tunnel_encap *e)
+{
+	size_t len;
+	bool need_priv = false;
+
+	len = sizeof(struct udphdr) + sizeof(struct guehdr);
+
+	if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
+		len += GUE_PLEN_REMCSUM;
+		need_priv = true;
+	}
+
+	len += need_priv ? GUE_LEN_PRIV : 0;
+
+	return len;
+}
+EXPORT_SYMBOL(gue_encap_hlen);
+
+static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
+			  struct flowi4 *fl4, u8 *protocol, __be16 sport)
+{
+	struct udphdr *uh;
+
+	skb_push(skb, sizeof(struct udphdr));
+	skb_reset_transport_header(skb);
+
+	uh = udp_hdr(skb);
+
+	uh->dest = e->dport;
+	uh->source = sport;
+	uh->len = htons(skb->len);
+	uh->check = 0;
+	udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
+		     fl4->saddr, fl4->daddr, skb->len);
+
+	*protocol = IPPROTO_UDP;
+}
+
+int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+		     u8 *protocol, struct flowi4 *fl4)
+{
+	bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
+	int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+	__be16 sport;
+
+	skb = iptunnel_handle_offloads(skb, csum, type);
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
+					       skb, 0, 0, false);
+	fou_build_udp(skb, e, fl4, protocol, sport);
+
+	return 0;
+}
+EXPORT_SYMBOL(fou_build_header);
+
+int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+		     u8 *protocol, struct flowi4 *fl4)
+{
+	bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
+	int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
+	struct guehdr *guehdr;
+	size_t hdrlen, optlen = 0;
+	__be16 sport;
+	void *data;
+	bool need_priv = false;
+
+	if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
+	    skb->ip_summed == CHECKSUM_PARTIAL) {
+		csum = false;
+		optlen += GUE_PLEN_REMCSUM;
+		type |= SKB_GSO_TUNNEL_REMCSUM;
+		need_priv = true;
+	}
+
+	optlen += need_priv ? GUE_LEN_PRIV : 0;
+
+	skb = iptunnel_handle_offloads(skb, csum, type);
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	/* Get source port (based on flow hash) before skb_push */
+	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
+					       skb, 0, 0, false);
+
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	skb_push(skb, hdrlen);
+
+	guehdr = (struct guehdr *)skb->data;
+
+	guehdr->control = 0;
+	guehdr->version = 0;
+	guehdr->hlen = optlen >> 2;
+	guehdr->flags = 0;
+	guehdr->proto_ctype = *protocol;
+
+	data = &guehdr[1];
+
+	if (need_priv) {
+		__be32 *flags = data;
+
+		guehdr->flags |= GUE_FLAG_PRIV;
+		*flags = 0;
+		data += GUE_LEN_PRIV;
+
+		if (type & SKB_GSO_TUNNEL_REMCSUM) {
+			u16 csum_start = skb_checksum_start_offset(skb);
+			__be16 *pd = data;
+
+			if (csum_start < hdrlen)
+				return -EINVAL;
+
+			csum_start -= hdrlen;
+			pd[0] = htons(csum_start);
+			pd[1] = htons(csum_start + skb->csum_offset);
+
+			if (!skb_is_gso(skb)) {
+				skb->ip_summed = CHECKSUM_NONE;
+				skb->encapsulation = 0;
+			}
+
+			*flags |= GUE_PFLAG_REMCSUM;
+			data += GUE_PLEN_REMCSUM;
+		}
+
+	}
+
+	fou_build_udp(skb, e, fl4, protocol, sport);
+
+	return 0;
+}
+EXPORT_SYMBOL(gue_build_header);
+
+#ifdef CONFIG_NET_FOU_IP_TUNNELS
+
+static const struct ip_tunnel_encap_ops fou_iptun_ops = {
+	.encap_hlen = fou_encap_hlen,
+	.build_header = fou_build_header,
+};
+
+static const struct ip_tunnel_encap_ops gue_iptun_ops = {
+	.encap_hlen = gue_encap_hlen,
+	.build_header = gue_build_header,
+};
+
+static int ip_tunnel_encap_add_fou_ops(void)
+{
+	int ret;
+
+	ret = ip_tunnel_encap_add_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+	if (ret < 0) {
+		pr_err("can't add fou ops\n");
+		return ret;
+	}
+
+	ret = ip_tunnel_encap_add_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
+	if (ret < 0) {
+		pr_err("can't add gue ops\n");
+		ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void ip_tunnel_encap_del_fou_ops(void)
+{
+	ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
+	ip_tunnel_encap_del_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
+}
+
+#else
+
+static int ip_tunnel_encap_add_fou_ops(void)
+{
+	return 0;
+}
+
+static void ip_tunnel_encap_del_fou_ops(void)
+{
+}
+
+#endif
+
+static __net_init int fou_init_net(struct net *net)
+{
+	struct fou_net *fn = net_generic(net, fou_net_id);
+
+	INIT_LIST_HEAD(&fn->fou_list);
+	mutex_init(&fn->fou_lock);
+	return 0;
+}
+
+static __net_exit void fou_exit_net(struct net *net)
+{
+	struct fou_net *fn = net_generic(net, fou_net_id);
+	struct fou *fou, *next;
+
+	/* Close all the FOU sockets */
+	mutex_lock(&fn->fou_lock);
+	list_for_each_entry_safe(fou, next, &fn->fou_list, list)
+		fou_release(fou);
+	mutex_unlock(&fn->fou_lock);
+}
+
+static struct pernet_operations fou_net_ops = {
+	.init = fou_init_net,
+	.exit = fou_exit_net,
+	.id   = &fou_net_id,
+	.size = sizeof(struct fou_net),
+};
+
+static int __init fou_init(void)
+{
+	int ret;
+
+	ret = register_pernet_device(&fou_net_ops);
+	if (ret)
+		goto exit;
+
+	ret = genl_register_family_with_ops(&fou_nl_family,
+					    fou_nl_ops);
+	if (ret < 0)
+		goto unregister;
+
+	ret = ip_tunnel_encap_add_fou_ops();
+	if (ret == 0)
+		return 0;
+
+	genl_unregister_family(&fou_nl_family);
+unregister:
+	unregister_pernet_device(&fou_net_ops);
+exit:
+	return ret;
+}
+
+static void __exit fou_fini(void)
+{
+	ip_tunnel_encap_del_fou_ops();
+	genl_unregister_family(&fou_nl_family);
+	unregister_pernet_device(&fou_net_ops);
+}
+
+module_init(fou_init);
+module_exit(fou_fini);
+MODULE_AUTHOR("Tom Herbert <therbert@google.com>");
+MODULE_LICENSE("GPL");