Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next

Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset container Netfilter/IPVS update for net-next:

1) Add UDP tunnel support for ICMP errors in IPVS.

Julian Anastasov says:

This patchset is a followup to the commit that adds UDP/GUE tunnel:
"ipvs: allow tunneling with gue encapsulation".

What we do is to put tunnel real servers in hash table (patch 1),
add function to lookup tunnels (patch 2) and use it to strip the
embedded tunnel headers from ICMP errors (patch 3).

2) Extend xt_owner to match for supplementary groups, from
   Lukasz Pawelczyk.

3) Remove unused oif field in flow_offload_tuple object, from
   Taehee Yoo.

4) Release basechain counters from workqueue to skip synchronize_rcu()
   call. From Florian Westphal.

5) Replace skb_make_writable() by skb_ensure_writable(). Patchset
   from Florian Westphal.

6) Checksum support for gue encapsulation in IPVS, from Jacky Hu.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 287 insertions, 43 deletions

diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c
index 7588aeaa605f..ba34ac25ee7b 100644
--- a/net/netfilter/ipvs/ip_vs_app.c
+++ b/net/netfilter/ipvs/ip_vs_app.c
@@ -363,7 +363,7 @@ static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb,
 	struct tcphdr *th;
 	__u32 seq;
 
-	if (!skb_make_writable(skb, tcp_offset + sizeof(*th)))
+	if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
 		return 0;
 
 	th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
@@ -440,7 +440,7 @@ static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb,
 	struct tcphdr *th;
 	__u32 seq;
 
-	if (!skb_make_writable(skb, tcp_offset + sizeof(*th)))
+	if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
 		return 0;
 
 	th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 8ebf21149ec3..58f84da6e3b0 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -39,6 +39,7 @@
 #include <net/tcp.h>
 #include <net/udp.h>
 #include <net/icmp.h>                   /* for icmp_send */
+#include <net/gue.h>
 #include <net/route.h>
 #include <net/ip6_checksum.h>
 #include <net/netns/generic.h>		/* net_generic() */
@@ -897,7 +898,7 @@ static int handle_response_icmp(int af, struct sk_buff *skb,
 	if (IPPROTO_TCP == protocol || IPPROTO_UDP == protocol ||
 	    IPPROTO_SCTP == protocol)
 		offset += 2 * sizeof(__u16);
-	if (!skb_make_writable(skb, offset))
+	if (skb_ensure_writable(skb, offset))
 		goto out;
 
 #ifdef CONFIG_IP_VS_IPV6
@@ -1287,7 +1288,7 @@ handle_response(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
 
 	IP_VS_DBG_PKT(11, af, pp, skb, iph->off, "Outgoing packet");
 
-	if (!skb_make_writable(skb, iph->len))
+	if (skb_ensure_writable(skb, iph->len))
 		goto drop;
 
 	/* mangle the packet */
@@ -1579,6 +1580,41 @@ ip_vs_try_to_schedule(struct netns_ipvs *ipvs, int af, struct sk_buff *skb,
 	return 1;
 }
 
+/* Check the UDP tunnel and return its header length */
+static int ipvs_udp_decap(struct netns_ipvs *ipvs, struct sk_buff *skb,
+			  unsigned int offset, __u16 af,
+			  const union nf_inet_addr *daddr, __u8 *proto)
+{
+	struct udphdr _udph, *udph;
+	struct ip_vs_dest *dest;
+
+	udph = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
+	if (!udph)
+		goto unk;
+	offset += sizeof(struct udphdr);
+	dest = ip_vs_find_tunnel(ipvs, af, daddr, udph->dest);
+	if (!dest)
+		goto unk;
+	if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		struct guehdr _gueh, *gueh;
+
+		gueh = skb_header_pointer(skb, offset, sizeof(_gueh), &_gueh);
+		if (!gueh)
+			goto unk;
+		if (gueh->control != 0 || gueh->version != 0)
+			goto unk;
+		/* Later we can support also IPPROTO_IPV6 */
+		if (gueh->proto_ctype != IPPROTO_IPIP)
+			goto unk;
+		*proto = gueh->proto_ctype;
+		return sizeof(struct udphdr) + sizeof(struct guehdr) +
+		       (gueh->hlen << 2);
+	}
+
+unk:
+	return 0;
+}
+
 /*
  *	Handle ICMP messages in the outside-to-inside direction (incoming).
  *	Find any that might be relevant, check against existing connections,
@@ -1598,6 +1634,7 @@ ip_vs_in_icmp(struct netns_ipvs *ipvs, struct sk_buff *skb, int *related,
 	struct ip_vs_proto_data *pd;
 	unsigned int offset, offset2, ihl, verdict;
 	bool ipip, new_cp = false;
+	union nf_inet_addr *raddr;
 
 	*related = 1;
 
@@ -1636,20 +1673,51 @@ ip_vs_in_icmp(struct netns_ipvs *ipvs, struct sk_buff *skb, int *related,
 	cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 	if (cih == NULL)
 		return NF_ACCEPT; /* The packet looks wrong, ignore */
+	raddr = (union nf_inet_addr *)&cih->daddr;
 
 	/* Special case for errors for IPIP packets */
 	ipip = false;
 	if (cih->protocol == IPPROTO_IPIP) {
+		struct ip_vs_dest *dest;
+
 		if (unlikely(cih->frag_off & htons(IP_OFFSET)))
 			return NF_ACCEPT;
 		/* Error for our IPIP must arrive at LOCAL_IN */
 		if (!(skb_rtable(skb)->rt_flags & RTCF_LOCAL))
 			return NF_ACCEPT;
+		dest = ip_vs_find_tunnel(ipvs, AF_INET, raddr, 0);
+		/* Only for known tunnel */
+		if (!dest || dest->tun_type != IP_VS_CONN_F_TUNNEL_TYPE_IPIP)
+			return NF_ACCEPT;
 		offset += cih->ihl * 4;
 		cih = skb_header_pointer(skb, offset, sizeof(_ciph), &_ciph);
 		if (cih == NULL)
 			return NF_ACCEPT; /* The packet looks wrong, ignore */
 		ipip = true;
+	} else if (cih->protocol == IPPROTO_UDP &&	/* Can be UDP encap */
+		   /* Error for our tunnel must arrive at LOCAL_IN */
+		   (skb_rtable(skb)->rt_flags & RTCF_LOCAL)) {
+		__u8 iproto;
+		int ulen;
+
+		/* Non-first fragment has no UDP header */
+		if (unlikely(cih->frag_off & htons(IP_OFFSET)))
+			return NF_ACCEPT;
+		offset2 = offset + cih->ihl * 4;
+		ulen = ipvs_udp_decap(ipvs, skb, offset2, AF_INET, raddr,
+				      &iproto);
+		if (ulen > 0) {
+			/* Skip IP and UDP tunnel headers */
+			offset = offset2 + ulen;
+			/* Now we should be at the original IP header */
+			cih = skb_header_pointer(skb, offset, sizeof(_ciph),
+						 &_ciph);
+			if (cih && cih->version == 4 && cih->ihl >= 5 &&
+			    iproto == IPPROTO_IPIP)
+				ipip = true;
+			else
+				return NF_ACCEPT;
+		}
 	}
 
 	pd = ip_vs_proto_data_get(ipvs, cih->protocol);
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 0e887159425c..ad19ac08622f 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -515,15 +515,36 @@ static inline unsigned int ip_vs_rs_hashkey(int af,
 static void ip_vs_rs_hash(struct netns_ipvs *ipvs, struct ip_vs_dest *dest)
 {
 	unsigned int hash;
+	__be16 port;
 
 	if (dest->in_rs_table)
 		return;
 
+	switch (IP_VS_DFWD_METHOD(dest)) {
+	case IP_VS_CONN_F_MASQ:
+		port = dest->port;
+		break;
+	case IP_VS_CONN_F_TUNNEL:
+		switch (dest->tun_type) {
+		case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
+			port = dest->tun_port;
+			break;
+		case IP_VS_CONN_F_TUNNEL_TYPE_IPIP:
+			port = 0;
+			break;
+		default:
+			return;
+		}
+		break;
+	default:
+		return;
+	}
+
 	/*
 	 *	Hash by proto,addr,port,
 	 *	which are the parameters of the real service.
 	 */
-	hash = ip_vs_rs_hashkey(dest->af, &dest->addr, dest->port);
+	hash = ip_vs_rs_hashkey(dest->af, &dest->addr, port);
 
 	hlist_add_head_rcu(&dest->d_list, &ipvs->rs_table[hash]);
 	dest->in_rs_table = 1;
@@ -555,7 +576,8 @@ bool ip_vs_has_real_service(struct netns_ipvs *ipvs, int af, __u16 protocol,
 		if (dest->port == dport &&
 		    dest->af == af &&
 		    ip_vs_addr_equal(af, &dest->addr, daddr) &&
-		    (dest->protocol == protocol || dest->vfwmark)) {
+		    (dest->protocol == protocol || dest->vfwmark) &&
+		    IP_VS_DFWD_METHOD(dest) == IP_VS_CONN_F_MASQ) {
 			/* HIT */
 			return true;
 		}
@@ -585,7 +607,37 @@ struct ip_vs_dest *ip_vs_find_real_service(struct netns_ipvs *ipvs, int af,
 		if (dest->port == dport &&
 		    dest->af == af &&
 		    ip_vs_addr_equal(af, &dest->addr, daddr) &&
-			(dest->protocol == protocol || dest->vfwmark)) {
+		    (dest->protocol == protocol || dest->vfwmark) &&
+		    IP_VS_DFWD_METHOD(dest) == IP_VS_CONN_F_MASQ) {
+			/* HIT */
+			return dest;
+		}
+	}
+
+	return NULL;
+}
+
+/* Find real service record by <af,addr,tun_port>.
+ * In case of multiple records with the same <af,addr,tun_port>, only
+ * the first found record is returned.
+ *
+ * To be called under RCU lock.
+ */
+struct ip_vs_dest *ip_vs_find_tunnel(struct netns_ipvs *ipvs, int af,
+				     const union nf_inet_addr *daddr,
+				     __be16 tun_port)
+{
+	struct ip_vs_dest *dest;
+	unsigned int hash;
+
+	/* Check for "full" addressed entries */
+	hash = ip_vs_rs_hashkey(af, daddr, tun_port);
+
+	hlist_for_each_entry_rcu(dest, &ipvs->rs_table[hash], d_list) {
+		if (dest->tun_port == tun_port &&
+		    dest->af == af &&
+		    ip_vs_addr_equal(af, &dest->addr, daddr) &&
+		    IP_VS_DFWD_METHOD(dest) == IP_VS_CONN_F_TUNNEL) {
 			/* HIT */
 			return dest;
 		}
@@ -831,24 +883,29 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
 	conn_flags = udest->conn_flags & IP_VS_CONN_F_DEST_MASK;
 	conn_flags |= IP_VS_CONN_F_INACTIVE;
 
+	/* Need to rehash? */
+	if ((udest->conn_flags & IP_VS_CONN_F_FWD_MASK) !=
+	    IP_VS_DFWD_METHOD(dest) ||
+	    udest->tun_type != dest->tun_type ||
+	    udest->tun_port != dest->tun_port)
+		ip_vs_rs_unhash(dest);
+
 	/* set the tunnel info */
 	dest->tun_type = udest->tun_type;
 	dest->tun_port = udest->tun_port;
+	dest->tun_flags = udest->tun_flags;
 
 	/* set the IP_VS_CONN_F_NOOUTPUT flag if not masquerading/NAT */
 	if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != IP_VS_CONN_F_MASQ) {
 		conn_flags |= IP_VS_CONN_F_NOOUTPUT;
 	} else {
-		/*
-		 *    Put the real service in rs_table if not present.
-		 *    For now only for NAT!
-		 */
-		ip_vs_rs_hash(ipvs, dest);
 		/* FTP-NAT requires conntrack for mangling */
 		if (svc->port == FTPPORT)
 			ip_vs_register_conntrack(svc);
 	}
 	atomic_set(&dest->conn_flags, conn_flags);
+	/* Put the real service in rs_table if not present. */
+	ip_vs_rs_hash(ipvs, dest);
 
 	/* bind the service */
 	old_svc = rcu_dereference_protected(dest->svc, 1);
@@ -2911,6 +2968,7 @@ static const struct nla_policy ip_vs_dest_policy[IPVS_DEST_ATTR_MAX + 1] = {
 	[IPVS_DEST_ATTR_ADDR_FAMILY]	= { .type = NLA_U16 },
 	[IPVS_DEST_ATTR_TUN_TYPE]	= { .type = NLA_U8 },
 	[IPVS_DEST_ATTR_TUN_PORT]	= { .type = NLA_U16 },
+	[IPVS_DEST_ATTR_TUN_FLAGS]	= { .type = NLA_U16 },
 };
 
 static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
@@ -3217,6 +3275,8 @@ static int ip_vs_genl_fill_dest(struct sk_buff *skb, struct ip_vs_dest *dest)
 		       dest->tun_type) ||
 	    nla_put_be16(skb, IPVS_DEST_ATTR_TUN_PORT,
 			 dest->tun_port) ||
+	    nla_put_u16(skb, IPVS_DEST_ATTR_TUN_FLAGS,
+			dest->tun_flags) ||
 	    nla_put_u32(skb, IPVS_DEST_ATTR_U_THRESH, dest->u_threshold) ||
 	    nla_put_u32(skb, IPVS_DEST_ATTR_L_THRESH, dest->l_threshold) ||
 	    nla_put_u32(skb, IPVS_DEST_ATTR_ACTIVE_CONNS,
@@ -3337,7 +3397,8 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
 	/* If a full entry was requested, check for the additional fields */
 	if (full_entry) {
 		struct nlattr *nla_fwd, *nla_weight, *nla_u_thresh,
-			      *nla_l_thresh, *nla_tun_type, *nla_tun_port;
+			      *nla_l_thresh, *nla_tun_type, *nla_tun_port,
+			      *nla_tun_flags;
 
 		nla_fwd		= attrs[IPVS_DEST_ATTR_FWD_METHOD];
 		nla_weight	= attrs[IPVS_DEST_ATTR_WEIGHT];
@@ -3345,6 +3406,7 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
 		nla_l_thresh	= attrs[IPVS_DEST_ATTR_L_THRESH];
 		nla_tun_type	= attrs[IPVS_DEST_ATTR_TUN_TYPE];
 		nla_tun_port	= attrs[IPVS_DEST_ATTR_TUN_PORT];
+		nla_tun_flags	= attrs[IPVS_DEST_ATTR_TUN_FLAGS];
 
 		if (!(nla_fwd && nla_weight && nla_u_thresh && nla_l_thresh))
 			return -EINVAL;
@@ -3360,6 +3422,9 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
 
 		if (nla_tun_port)
 			udest->tun_port = nla_get_be16(nla_tun_port);
+
+		if (nla_tun_flags)
+			udest->tun_flags = nla_get_u16(nla_tun_flags);
 	}
 
 	return 0;
diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
index fe69d46ff779..5cbefa927f09 100644
--- a/net/netfilter/ipvs/ip_vs_ftp.c
+++ b/net/netfilter/ipvs/ip_vs_ftp.c
@@ -273,7 +273,7 @@ static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
 		return 1;
 
 	/* Linear packets are much easier to deal with. */
-	if (!skb_make_writable(skb, skb->len))
+	if (skb_ensure_writable(skb, skb->len))
 		return 0;
 
 	if (cp->app_data == (void *) IP_VS_FTP_PASV) {
@@ -439,7 +439,7 @@ static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
 		return 1;
 
 	/* Linear packets are much easier to deal with. */
-	if (!skb_make_writable(skb, skb->len))
+	if (skb_ensure_writable(skb, skb->len))
 		return 0;
 
 	data = data_start = ip_vs_ftp_data_ptr(skb, ipvsh);
diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c
index b58ddb7dffd1..a0921adc31a9 100644
--- a/net/netfilter/ipvs/ip_vs_proto_sctp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c
@@ -101,7 +101,7 @@ sctp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 #endif
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, sctphoff + sizeof(*sctph)))
+	if (skb_ensure_writable(skb, sctphoff + sizeof(*sctph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
@@ -148,7 +148,7 @@ sctp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 #endif
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, sctphoff + sizeof(*sctph)))
+	if (skb_ensure_writable(skb, sctphoff + sizeof(*sctph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
diff --git a/net/netfilter/ipvs/ip_vs_proto_tcp.c b/net/netfilter/ipvs/ip_vs_proto_tcp.c
index 00ce07dda980..089ee592a955 100644
--- a/net/netfilter/ipvs/ip_vs_proto_tcp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_tcp.c
@@ -163,7 +163,7 @@ tcp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 	oldlen = skb->len - tcphoff;
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
+	if (skb_ensure_writable(skb, tcphoff + sizeof(*tcph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
@@ -241,7 +241,7 @@ tcp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 	oldlen = skb->len - tcphoff;
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
+	if (skb_ensure_writable(skb, tcphoff + sizeof(*tcph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
diff --git a/net/netfilter/ipvs/ip_vs_proto_udp.c b/net/netfilter/ipvs/ip_vs_proto_udp.c
index 92c078abcb3e..de366aa3c03b 100644
--- a/net/netfilter/ipvs/ip_vs_proto_udp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_udp.c
@@ -153,7 +153,7 @@ udp_snat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 	oldlen = skb->len - udphoff;
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, udphoff+sizeof(*udph)))
+	if (skb_ensure_writable(skb, udphoff + sizeof(*udph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
@@ -236,7 +236,7 @@ udp_dnat_handler(struct sk_buff *skb, struct ip_vs_protocol *pp,
 	oldlen = skb->len - udphoff;
 
 	/* csum_check requires unshared skb */
-	if (!skb_make_writable(skb, udphoff+sizeof(*udph)))
+	if (skb_ensure_writable(skb, udphoff + sizeof(*udph)))
 		return 0;
 
 	if (unlikely(cp->app != NULL)) {
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 8d6f94b67772..af3379d5e5bc 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -40,6 +40,7 @@
 #include <net/ipv6.h>
 #include <net/ip6_route.h>
 #include <net/ip_tunnels.h>
+#include <net/ip6_checksum.h>
 #include <net/addrconf.h>
 #include <linux/icmpv6.h>
 #include <linux/netfilter.h>
@@ -279,7 +280,7 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs,
 		}
 
 		/* don't propagate ttl change to cloned packets */
-		if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
+		if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
 			return false;
 
 		ipv6_hdr(skb)->hop_limit--;
@@ -294,7 +295,7 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs,
 		}
 
 		/* don't propagate ttl change to cloned packets */
-		if (!skb_make_writable(skb, sizeof(struct iphdr)))
+		if (skb_ensure_writable(skb, sizeof(struct iphdr)))
 			return false;
 
 		/* Decrease ttl */
@@ -385,8 +386,13 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
 		mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 		if (!dest)
 			goto err_put;
-		if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
+		if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
 			mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
+			if ((dest->tun_flags &
+			     IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+			    skb->ip_summed == CHECKSUM_PARTIAL)
+				mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
+		}
 		if (mtu < 68) {
 			IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
 			goto err_put;
@@ -540,8 +546,13 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
 		mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
 		if (!dest)
 			goto err_put;
-		if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
+		if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
 			mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
+			if ((dest->tun_flags &
+			     IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+			    skb->ip_summed == CHECKSUM_PARTIAL)
+				mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
+		}
 		if (mtu < IPV6_MIN_MTU) {
 			IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
 				     IPV6_MIN_MTU);
@@ -796,7 +807,7 @@ ip_vs_nat_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 	}
 
 	/* copy-on-write the packet before mangling it */
-	if (!skb_make_writable(skb, sizeof(struct iphdr)))
+	if (skb_ensure_writable(skb, sizeof(struct iphdr)))
 		goto tx_error;
 
 	if (skb_cow(skb, rt->dst.dev->hard_header_len))
@@ -885,7 +896,7 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	}
 
 	/* copy-on-write the packet before mangling it */
-	if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
+	if (skb_ensure_writable(skb, sizeof(struct ipv6hdr)))
 		goto tx_error;
 
 	if (skb_cow(skb, rt->dst.dev->hard_header_len))
@@ -1006,17 +1017,56 @@ ipvs_gue_encap(struct net *net, struct sk_buff *skb,
 	__be16 sport = udp_flow_src_port(net, skb, 0, 0, false);
 	struct udphdr  *udph;	/* Our new UDP header */
 	struct guehdr  *gueh;	/* Our new GUE header */
+	size_t hdrlen, optlen = 0;
+	void *data;
+	bool need_priv = false;
+
+	if ((cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+	    skb->ip_summed == CHECKSUM_PARTIAL) {
+		optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
+		need_priv = true;
+	}
 
-	skb_push(skb, sizeof(struct guehdr));
+	hdrlen = sizeof(struct guehdr) + optlen;
+
+	skb_push(skb, hdrlen);
 
 	gueh = (struct guehdr *)skb->data;
 
 	gueh->control = 0;
 	gueh->version = 0;
-	gueh->hlen = 0;
+	gueh->hlen = optlen >> 2;
 	gueh->flags = 0;
 	gueh->proto_ctype = *next_protocol;
 
+	data = &gueh[1];
+
+	if (need_priv) {
+		__be32 *flags = data;
+		u16 csum_start = skb_checksum_start_offset(skb);
+		__be16 *pd;
+
+		gueh->flags |= GUE_FLAG_PRIV;
+		*flags = 0;
+		data += GUE_LEN_PRIV;
+
+		if (csum_start < hdrlen)
+			return -EINVAL;
+
+		csum_start -= hdrlen;
+		pd = data;
+		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;
+	}
+
 	skb_push(skb, sizeof(struct udphdr));
 	skb_reset_transport_header(skb);
 
@@ -1070,6 +1120,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 	unsigned int max_headroom;		/* The extra header space needed */
 	int ret, local;
 	int tun_type, gso_type;
+	int tun_flags;
 
 	EnterFunction(10);
 
@@ -1092,9 +1143,19 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
 
 	tun_type = cp->dest->tun_type;
+	tun_flags = cp->dest->tun_flags;
 
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		size_t gue_hdrlen, gue_optlen = 0;
+
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+		    skb->ip_summed == CHECKSUM_PARTIAL) {
+			gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
+		}
+		gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
+
+		max_headroom += sizeof(struct udphdr) + gue_hdrlen;
+	}
 
 	/* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
 	dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
@@ -1105,8 +1166,17 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 		goto tx_error;
 
 	gso_type = __tun_gso_type_mask(AF_INET, cp->af);
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		gso_type |= SKB_GSO_UDP_TUNNEL;
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
+		    (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
+			gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+		else
+			gso_type |= SKB_GSO_UDP_TUNNEL;
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+		    skb->ip_summed == CHECKSUM_PARTIAL) {
+			gso_type |= SKB_GSO_TUNNEL_REMCSUM;
+		}
+	}
 
 	if (iptunnel_handle_offloads(skb, gso_type))
 		goto tx_error;
@@ -1115,8 +1185,19 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 
 	skb_set_inner_ipproto(skb, next_protocol);
 
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		ipvs_gue_encap(net, skb, cp, &next_protocol);
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		bool check = false;
+
+		if (ipvs_gue_encap(net, skb, cp, &next_protocol))
+			goto tx_error;
+
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
+		    (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
+			check = true;
+
+		udp_set_csum(!check, skb, saddr, cp->daddr.ip, skb->len);
+	}
+
 
 	skb_push(skb, sizeof(struct iphdr));
 	skb_reset_network_header(skb);
@@ -1174,6 +1255,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	unsigned int max_headroom;	/* The extra header space needed */
 	int ret, local;
 	int tun_type, gso_type;
+	int tun_flags;
 
 	EnterFunction(10);
 
@@ -1197,9 +1279,19 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
 
 	tun_type = cp->dest->tun_type;
+	tun_flags = cp->dest->tun_flags;
 
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		size_t gue_hdrlen, gue_optlen = 0;
+
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+		    skb->ip_summed == CHECKSUM_PARTIAL) {
+			gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
+		}
+		gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
+
+		max_headroom += sizeof(struct udphdr) + gue_hdrlen;
+	}
 
 	skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
 					 &next_protocol, &payload_len,
@@ -1208,8 +1300,17 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 		goto tx_error;
 
 	gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		gso_type |= SKB_GSO_UDP_TUNNEL;
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
+		    (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
+			gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+		else
+			gso_type |= SKB_GSO_UDP_TUNNEL;
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
+		    skb->ip_summed == CHECKSUM_PARTIAL) {
+			gso_type |= SKB_GSO_TUNNEL_REMCSUM;
+		}
+	}
 
 	if (iptunnel_handle_offloads(skb, gso_type))
 		goto tx_error;
@@ -1218,8 +1319,18 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 
 	skb_set_inner_ipproto(skb, next_protocol);
 
-	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
-		ipvs_gue_encap(net, skb, cp, &next_protocol);
+	if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
+		bool check = false;
+
+		if (ipvs_gue_encap(net, skb, cp, &next_protocol))
+			goto tx_error;
+
+		if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
+		    (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
+			check = true;
+
+		udp6_set_csum(!check, skb, &saddr, &cp->daddr.in6, skb->len);
+	}
 
 	skb_push(skb, sizeof(struct ipv6hdr));
 	skb_reset_network_header(skb);
@@ -1404,7 +1515,7 @@ ip_vs_icmp_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
 	}
 
 	/* copy-on-write the packet before mangling it */
-	if (!skb_make_writable(skb, offset))
+	if (skb_ensure_writable(skb, offset))
 		goto tx_error;
 
 	if (skb_cow(skb, rt->dst.dev->hard_header_len))
@@ -1493,7 +1604,7 @@ ip_vs_icmp_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	}
 
 	/* copy-on-write the packet before mangling it */
-	if (!skb_make_writable(skb, offset))
+	if (skb_ensure_writable(skb, offset))
 		goto tx_error;
 
 	if (skb_cow(skb, rt->dst.dev->hard_header_len))