recipes-kernel/linux/linux-mediatek-5.4/mediatek/nf_hnat/999-4501-mtk-pptp-offload-support.patch

--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -33,6 +33,7 @@
 #include <net/route.h>
 #include <net/gre.h>
 #include <net/pptp.h>
+#include <net/netfilter/nf_flow_table.h>
 
 #include <linux/uaccess.h>
 
@@ -40,6 +41,9 @@
 
 #define MAX_CALLID 65535
 
+int (*mtk_pptp_seq_next)(u16 call_id, u32 *val) = NULL;
+EXPORT_SYMBOL(mtk_pptp_seq_next);
+
 static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
 static struct pppox_sock __rcu **callid_sock;
 
@@ -128,6 +132,26 @@ static void del_chan(struct pppox_sock *
 	spin_unlock(&chan_lock);
 }
 
+#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
+static int pptp_flow_offload_check(struct ppp_channel *chan,
+				   struct flow_offload_hw_path *path)
+{
+	struct sock *sk = (struct sock *)chan->private;
+	struct pppox_sock *po = pppox_sk(sk);
+
+	if (path->flags & FLOW_OFFLOAD_PATH_TNL)
+		return -EEXIST;
+
+	if (sk_pppox(po)->sk_state & PPPOX_DEAD)
+		return -EINVAL;
+
+	path->flags |= FLOW_OFFLOAD_PATH_TNL;
+	path->tnl_type = FLOW_OFFLOAD_TNL_PPTP;
+
+	return 0;
+}
+#endif /* IS_ENABLED(CONFIG_NF_FLOW_TABLE) */
+
 static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 {
 	struct sock *sk = (struct sock *) chan->private;
@@ -140,6 +164,7 @@ static int pptp_xmit(struct ppp_channel
 	int islcp;
 	int len;
 	unsigned char *data;
+	u32 seq_sent_hw;
 	__u32 seq_recv;
 
 
@@ -204,7 +229,14 @@ static int pptp_xmit(struct ppp_channel
 	hdr->gre_hd.protocol = GRE_PROTO_PPP;
 	hdr->call_id = htons(opt->dst_addr.call_id);
 
-	hdr->seq = htonl(++opt->seq_sent);
+	if (mtk_pptp_seq_next && !mtk_pptp_seq_next(opt->dst_addr.call_id,
+						    &seq_sent_hw)) {
+		opt->seq_sent = seq_sent_hw;
+		hdr->seq = htonl(opt->seq_sent);
+	} else {
+		hdr->seq = htonl(++opt->seq_sent);
+	}
+
 	if (opt->ack_sent != seq_recv)	{
 		/* send ack with this message */
 		hdr->gre_hd.flags |= GRE_ACK;
@@ -598,6 +630,9 @@ static int pptp_ppp_ioctl(struct ppp_cha
 static const struct ppp_channel_ops pptp_chan_ops = {
 	.start_xmit = pptp_xmit,
 	.ioctl      = pptp_ppp_ioctl,
+#if IS_ENABLED(CONFIG_NF_FLOW_TABLE)
+	.flow_offload_check = pptp_flow_offload_check,
+#endif /* IS_ENABLED(CONFIG_NF_FLOW_TABLE) */
 };
 
 static struct proto pptp_sk_proto __read_mostly = {
--- a/include/net/pptp.h
+++ b/include/net/pptp.h
@@ -2,6 +2,8 @@
 #ifndef _NET_PPTP_H
 #define _NET_PPTP_H
 
+#include <net/gre.h>
+
 #define PPP_LCP_ECHOREQ 0x09
 #define PPP_LCP_ECHOREP 0x0A
 #define SC_RCV_BITS     (SC_RCV_B7_1|SC_RCV_B7_0|SC_RCV_ODDP|SC_RCV_EVNP)
@@ -20,5 +22,7 @@ struct pptp_gre_header {
 	__be32 ack;
 } __packed;
 
+/* symbol exported from linux kernel driver/net/ppp/pptp.c */
+extern int (*mtk_pptp_seq_next)(uint16_t call_id, uint32_t *val);
 
 #endif