v4.19.13 snapshot.
diff --git a/net/sctp/offload.c b/net/sctp/offload.c
new file mode 100644
index 0000000..123e9f2
--- /dev/null
+++ b/net/sctp/offload.c
@@ -0,0 +1,129 @@
+/*
+ * sctp_offload - GRO/GSO Offloading for SCTP
+ *
+ * Copyright (C) 2015, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/socket.h>
+#include <linux/sctp.h>
+#include <linux/proc_fs.h>
+#include <linux/vmalloc.h>
+#include <linux/module.h>
+#include <linux/kfifo.h>
+#include <linux/time.h>
+#include <net/net_namespace.h>
+
+#include <linux/skbuff.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/checksum.h>
+#include <net/protocol.h>
+
+static __le32 sctp_gso_make_checksum(struct sk_buff *skb)
+{
+ skb->ip_summed = CHECKSUM_NONE;
+ skb->csum_not_inet = 0;
+ return sctp_compute_cksum(skb, skb_transport_offset(skb));
+}
+
+static struct sk_buff *sctp_gso_segment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct sctphdr *sh;
+
+ if (!skb_is_gso_sctp(skb))
+ goto out;
+
+ sh = sctp_hdr(skb);
+ if (!pskb_may_pull(skb, sizeof(*sh)))
+ goto out;
+
+ __skb_pull(skb, sizeof(*sh));
+
+ if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+ /* Packet is from an untrusted source, reset gso_segs. */
+ struct skb_shared_info *pinfo = skb_shinfo(skb);
+ struct sk_buff *frag_iter;
+
+ pinfo->gso_segs = 0;
+ if (skb->len != skb->data_len) {
+ /* Means we have chunks in here too */
+ pinfo->gso_segs++;
+ }
+
+ skb_walk_frags(skb, frag_iter)
+ pinfo->gso_segs++;
+
+ segs = NULL;
+ goto out;
+ }
+
+ segs = skb_segment(skb, features | NETIF_F_HW_CSUM | NETIF_F_SG);
+ if (IS_ERR(segs))
+ goto out;
+
+ /* All that is left is update SCTP CRC if necessary */
+ if (!(features & NETIF_F_SCTP_CRC)) {
+ for (skb = segs; skb; skb = skb->next) {
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ sh = sctp_hdr(skb);
+ sh->checksum = sctp_gso_make_checksum(skb);
+ }
+ }
+ }
+
+out:
+ return segs;
+}
+
+static const struct net_offload sctp_offload = {
+ .callbacks = {
+ .gso_segment = sctp_gso_segment,
+ },
+};
+
+static const struct net_offload sctp6_offload = {
+ .callbacks = {
+ .gso_segment = sctp_gso_segment,
+ },
+};
+
+static const struct skb_checksum_ops crc32c_csum_ops = {
+ .update = sctp_csum_update,
+ .combine = sctp_csum_combine,
+};
+
+int __init sctp_offload_init(void)
+{
+ int ret;
+
+ ret = inet_add_offload(&sctp_offload, IPPROTO_SCTP);
+ if (ret)
+ goto out;
+
+ ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
+ if (ret)
+ goto ipv4;
+
+ crc32c_csum_stub = &crc32c_csum_ops;
+ return ret;
+
+ipv4:
+ inet_del_offload(&sctp_offload, IPPROTO_SCTP);
+out:
+ return ret;
+}