--- zzzz-none-000/linux-3.10.107/include/net/inet_ecn.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/net/inet_ecn.h	2021-02-04 17:41:59.000000000 +0000
@@ -111,17 +111,31 @@
 
 struct ipv6hdr;
 
-static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
+/* Note:
+ * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
+ * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
+ * In IPv6 case, no checksum compensates the change in IPv6 header,
+ * so we have to update skb->csum.
+ */
+static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
 {
+	__be32 from, to;
+
 	if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
 		return 0;
-	*(__be32*)iph |= htonl(INET_ECN_CE << 20);
+
+	from = *(__be32 *)iph;
+	to = from | htonl(INET_ECN_CE << 20);
+	net_hdr_word(iph) |= htonl(INET_ECN_CE << 20);
+
+	if (skb->ip_summed == CHECKSUM_COMPLETE)
+		skb->csum = csum_add(csum_sub(skb->csum, from), to);
 	return 1;
 }
 
 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
 {
-	*(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
+	net_hdr_word(iph) &= ~htonl(INET_ECN_MASK << 20);
 }
 
 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
@@ -134,13 +148,15 @@
 {
 	switch (skb->protocol) {
 	case cpu_to_be16(ETH_P_IP):
-		if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
+		if (skb_network_header(skb) + sizeof(struct iphdr) <=
+		    skb_tail_pointer(skb))
 			return IP_ECN_set_ce(ip_hdr(skb));
 		break;
 
 	case cpu_to_be16(ETH_P_IPV6):
-		if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail)
-			return IP6_ECN_set_ce(ipv6_hdr(skb));
+		if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
+		    skb_tail_pointer(skb))
+			return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
 		break;
 	}
 
@@ -148,7 +164,7 @@
 }
 
 /*
- * RFC 6080 4.2
+ * RFC 6040 4.2
  *  To decapsulate the inner header at the tunnel egress, a compliant
  *  tunnel egress MUST set the outgoing ECN field to the codepoint at the
  *  intersection of the appropriate arriving inner header (row) and outer