diff --git a/net/core/dev.c b/net/core/dev.c
index 0096349..4d2b516 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1162,9 +1162,17 @@
 	unsigned int csum;
 	int ret = 0, offset = skb->h.raw - skb->data;
 
-	if (inward) {
-		skb->ip_summed = CHECKSUM_NONE;
-		goto out;
+	if (inward)
+		goto out_set_summed;
+
+	if (unlikely(skb_shinfo(skb)->gso_size)) {
+		static int warned;
+
+		WARN_ON(!warned);
+		warned = 1;
+
+		/* Let GSO fix up the checksum. */
+		goto out_set_summed;
 	}
 
 	if (skb_cloned(skb)) {
@@ -1181,6 +1189,8 @@
 	BUG_ON(skb->csum + 2 > offset);
 
 	*(u16*)(skb->h.raw + skb->csum) = csum_fold(csum);
+
+out_set_summed:
 	skb->ip_summed = CHECKSUM_NONE;
 out:	
 	return ret;
@@ -1201,17 +1211,35 @@
 	struct sk_buff *segs = ERR_PTR(-EPROTONOSUPPORT);
 	struct packet_type *ptype;
 	int type = skb->protocol;
+	int err;
 
 	BUG_ON(skb_shinfo(skb)->frag_list);
-	BUG_ON(skb->ip_summed != CHECKSUM_HW);
 
 	skb->mac.raw = skb->data;
 	skb->mac_len = skb->nh.raw - skb->data;
 	__skb_pull(skb, skb->mac_len);
 
+	if (unlikely(skb->ip_summed != CHECKSUM_HW)) {
+		static int warned;
+
+		WARN_ON(!warned);
+		warned = 1;
+
+		if (skb_header_cloned(skb) &&
+		    (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+			return ERR_PTR(err);
+	}
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type) & 15], list) {
 		if (ptype->type == type && !ptype->dev && ptype->gso_segment) {
+			if (unlikely(skb->ip_summed != CHECKSUM_HW)) {
+				err = ptype->gso_send_check(skb);
+				segs = ERR_PTR(err);
+				if (err || skb_gso_ok(skb, features))
+					break;
+				__skb_push(skb, skb->data - skb->nh.raw);
+			}
 			segs = ptype->gso_segment(skb, features);
 			break;
 		}
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 318d467..c84a320 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1097,6 +1097,40 @@
 
 EXPORT_SYMBOL(inet_sk_rebuild_header);
 
+static int inet_gso_send_check(struct sk_buff *skb)
+{
+	struct iphdr *iph;
+	struct net_protocol *ops;
+	int proto;
+	int ihl;
+	int err = -EINVAL;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
+		goto out;
+
+	iph = skb->nh.iph;
+	ihl = iph->ihl * 4;
+	if (ihl < sizeof(*iph))
+		goto out;
+
+	if (unlikely(!pskb_may_pull(skb, ihl)))
+		goto out;
+
+	skb->h.raw = __skb_pull(skb, ihl);
+	iph = skb->nh.iph;
+	proto = iph->protocol & (MAX_INET_PROTOS - 1);
+	err = -EPROTONOSUPPORT;
+
+	rcu_read_lock();
+	ops = rcu_dereference(inet_protos[proto]);
+	if (likely(ops && ops->gso_send_check))
+		err = ops->gso_send_check(skb);
+	rcu_read_unlock();
+
+out:
+	return err;
+}
+
 static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
@@ -1162,6 +1196,7 @@
 static struct net_protocol tcp_protocol = {
 	.handler =	tcp_v4_rcv,
 	.err_handler =	tcp_v4_err,
+	.gso_send_check = tcp_v4_gso_send_check,
 	.gso_segment =	tcp_tso_segment,
 	.no_policy =	1,
 };
@@ -1208,6 +1243,7 @@
 static struct packet_type ip_packet_type = {
 	.type = __constant_htons(ETH_P_IP),
 	.func = ip_rcv,
+	.gso_send_check = inet_gso_send_check,
 	.gso_segment = inet_gso_segment,
 };
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5a886e6..a891133 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -496,6 +496,24 @@
 	}
 }
 
+int tcp_v4_gso_send_check(struct sk_buff *skb)
+{
+	struct iphdr *iph;
+	struct tcphdr *th;
+
+	if (!pskb_may_pull(skb, sizeof(*th)))
+		return -EINVAL;
+
+	iph = skb->nh.iph;
+	th = skb->h.th;
+
+	th->check = 0;
+	th->check = ~tcp_v4_check(th, skb->len, iph->saddr, iph->daddr, 0);
+	skb->csum = offsetof(struct tcphdr, check);
+	skb->ip_summed = CHECKSUM_HW;
+	return 0;
+}
+
 /*
  *	This routine will send an RST to the other tcp.
  *
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 0c17dec..4332726 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -57,12 +57,71 @@
 
 DEFINE_SNMP_STAT(struct ipstats_mib, ipv6_statistics) __read_mostly;
 
+static struct inet6_protocol *ipv6_gso_pull_exthdrs(struct sk_buff *skb,
+						    int proto)
+{
+	struct inet6_protocol *ops = NULL;
+
+	for (;;) {
+		struct ipv6_opt_hdr *opth;
+		int len;
+
+		if (proto != NEXTHDR_HOP) {
+			ops = rcu_dereference(inet6_protos[proto]);
+
+			if (unlikely(!ops))
+				break;
+
+			if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
+				break;
+		}
+
+		if (unlikely(!pskb_may_pull(skb, 8)))
+			break;
+
+		opth = (void *)skb->data;
+		len = opth->hdrlen * 8 + 8;
+
+		if (unlikely(!pskb_may_pull(skb, len)))
+			break;
+
+		proto = opth->nexthdr;
+		__skb_pull(skb, len);
+	}
+
+	return ops;
+}
+
+static int ipv6_gso_send_check(struct sk_buff *skb)
+{
+	struct ipv6hdr *ipv6h;
+	struct inet6_protocol *ops;
+	int err = -EINVAL;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
+		goto out;
+
+	ipv6h = skb->nh.ipv6h;
+	__skb_pull(skb, sizeof(*ipv6h));
+	err = -EPROTONOSUPPORT;
+
+	rcu_read_lock();
+	ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
+	if (likely(ops && ops->gso_send_check)) {
+		skb->h.raw = skb->data;
+		err = ops->gso_send_check(skb);
+	}
+	rcu_read_unlock();
+
+out:
+	return err;
+}
+
 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, int features)
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
 	struct ipv6hdr *ipv6h;
 	struct inet6_protocol *ops;
-	int proto;
 
 	if (unlikely(skb_shinfo(skb)->gso_type &
 		     ~(SKB_GSO_UDP |
@@ -76,42 +135,15 @@
 		goto out;
 
 	ipv6h = skb->nh.ipv6h;
-	proto = ipv6h->nexthdr;
 	__skb_pull(skb, sizeof(*ipv6h));
+	segs = ERR_PTR(-EPROTONOSUPPORT);
 
 	rcu_read_lock();
-	for (;;) {
-		struct ipv6_opt_hdr *opth;
-		int len;
-
-		if (proto != NEXTHDR_HOP) {
-			ops = rcu_dereference(inet6_protos[proto]);
-
-			if (unlikely(!ops))
-				goto unlock;
-
-			if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
-				break;
-		}
-
-		if (unlikely(!pskb_may_pull(skb, 8)))
-			goto unlock;
-
-		opth = (void *)skb->data;
-		len = opth->hdrlen * 8 + 8;
-
-		if (unlikely(!pskb_may_pull(skb, len)))
-			goto unlock;
-
-		proto = opth->nexthdr;
-		__skb_pull(skb, len);
-	}
-
-	skb->h.raw = skb->data;
-	if (likely(ops->gso_segment))
+	ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
+	if (likely(ops && ops->gso_segment)) {
+		skb->h.raw = skb->data;
 		segs = ops->gso_segment(skb, features);
-
-unlock:
+	}
 	rcu_read_unlock();
 
 	if (unlikely(IS_ERR(segs)))
@@ -130,6 +162,7 @@
 static struct packet_type ipv6_packet_type = {
 	.type = __constant_htons(ETH_P_IPV6), 
 	.func = ipv6_rcv,
+	.gso_send_check = ipv6_gso_send_check,
 	.gso_segment = ipv6_gso_segment,
 };
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5bdcb90..923989d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -552,6 +552,24 @@
 	}
 }
 
+static int tcp_v6_gso_send_check(struct sk_buff *skb)
+{
+	struct ipv6hdr *ipv6h;
+	struct tcphdr *th;
+
+	if (!pskb_may_pull(skb, sizeof(*th)))
+		return -EINVAL;
+
+	ipv6h = skb->nh.ipv6h;
+	th = skb->h.th;
+
+	th->check = 0;
+	th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
+				     IPPROTO_TCP, 0);
+	skb->csum = offsetof(struct tcphdr, check);
+	skb->ip_summed = CHECKSUM_HW;
+	return 0;
+}
 
 static void tcp_v6_send_reset(struct sk_buff *skb)
 {
@@ -1603,6 +1621,7 @@
 static struct inet6_protocol tcpv6_protocol = {
 	.handler	=	tcp_v6_rcv,
 	.err_handler	=	tcp_v6_err,
+	.gso_send_check	=	tcp_v6_gso_send_check,
 	.gso_segment	=	tcp_tso_segment,
 	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 };