Author:  Pavithra R <pavir@codeaurora.org>
Date:    Sat Aug 1 13:55:33 2020 +0530

nat46: Set IPv6 traffic class from IPv4 ToS value

Set IPv6 traffic class from IPv4 ToS value during
IPv4 to IPv6 translation and vice-versa.

This patch is propagated from kernel 4.4 commit
1cd3b55b059d4513649bb73bc69da931ed3beb7b

Change-Id: Ia14e53447e829c8648c01656237ac902ad8674ec
Signed-off-by: Pavithra R <pavir@codeaurora.org>

--- a/nat46/modules/nat46-core.c
+++ b/nat46/modules/nat46-core.c
@@ -886,11 +886,12 @@ void *get_next_header_ptr6(void *pv6, in
 }
 
 void fill_v4hdr_from_v6hdr(struct iphdr * iph, struct ipv6hdr *ip6h, __u32 v4saddr, __u32 v4daddr, __u16 id, __u16 frag_off, __u16 proto, int l3_payload_len) {
+  uint32_t ver_class_flow = ntohl(*(__be32 *)ip6h);
   iph->ttl = ip6h->hop_limit;
   iph->saddr = v4saddr;
   iph->daddr = v4daddr;
   iph->protocol = proto;
-  *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (0x00/*tos*/ & 0xff));
+  *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | ((ver_class_flow >> 20) & 0xff));
   iph->frag_off = frag_off;
   iph->id = id;
   iph->tot_len = htons( l3_payload_len + IPV4HDRSIZE );
@@ -1859,7 +1860,7 @@ int nat46_ipv4_input(struct sk_buff *old
   uint16_t sport = 0, dport = 0;
 
   int err = 0;
-  int tclass = 0;
+  uint8_t tclass = 0;
   int flowlabel = 0;
   int check_for_l4 = 0;
   int having_l4 = 0;