v4.19.13 snapshot.
diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
new file mode 100644
index 0000000..e72947c
--- /dev/null
+++ b/net/ipv6/tcpv6_offload.c
@@ -0,0 +1,81 @@
+/*
+ * IPV6 GSO/GRO offload support
+ * Linux INET6 implementation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * TCPv6 GSO/GRO support
+ */
+#include <linux/skbuff.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/ip6_checksum.h>
+#include "ip6_offload.h"
+
+static struct sk_buff *tcp6_gro_receive(struct list_head *head,
+ struct sk_buff *skb)
+{
+ /* Don't bother verifying checksum if we're going to flush anyway. */
+ if (!NAPI_GRO_CB(skb)->flush &&
+ skb_gro_checksum_validate(skb, IPPROTO_TCP,
+ ip6_gro_compute_pseudo)) {
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+ }
+
+ return tcp_gro_receive(head, skb);
+}
+
+static int tcp6_gro_complete(struct sk_buff *skb, int thoff)
+{
+ const struct ipv6hdr *iph = ipv6_hdr(skb);
+ struct tcphdr *th = tcp_hdr(skb);
+
+ th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
+ &iph->daddr, 0);
+ skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
+
+ return tcp_gro_complete(skb);
+}
+
+static struct sk_buff *tcp6_gso_segment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct tcphdr *th;
+
+ if (!(skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
+ return ERR_PTR(-EINVAL);
+
+ if (!pskb_may_pull(skb, sizeof(*th)))
+ return ERR_PTR(-EINVAL);
+
+ if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
+ const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+ struct tcphdr *th = tcp_hdr(skb);
+
+ /* Set up pseudo header, usually expect stack to have done
+ * this.
+ */
+
+ th->check = 0;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ __tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
+ }
+
+ return tcp_gso_segment(skb, features);
+}
+static const struct net_offload tcpv6_offload = {
+ .callbacks = {
+ .gso_segment = tcp6_gso_segment,
+ .gro_receive = tcp6_gro_receive,
+ .gro_complete = tcp6_gro_complete,
+ },
+};
+
+int __init tcpv6_offload_init(void)
+{
+ return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
+}