tayga: fix broken ICMP checksum on big-endian machines

This patches fixes wrong ICMP checksum of translated packets on
big-endian machines #16715
The patch is authored by upstream author
Nathan Lutchansky <lutchann@litech.org>
Source of the patch: http://forum.mikrotik.com/viewtopic.php?f=15&t=82329

Signed-off-by: Ondrej Caletka <ondrej@caletka.cz>

diff --git a/ipv6/tayga/patches/002-bigendian_wrong_checksum.patch b/ipv6/tayga/patches/002-bigendian_wrong_checksum.patch
new file mode 100644 (file)
index 0000000..d8deac3
--- /dev/null
+++ b/ipv6/tayga/patches/002-bigendian_wrong_checksum.patch
@@ -0,0 +1,53 @@
+--- a/nat64.c
++++ b/nat64.c
+@@ -19,6 +19,11 @@
+ 
+ extern struct config *gcfg;
+ 
++static uint16_t checksum_extend_byte(uint8_t b)
++{
++      return htons(b << 8);
++}
++
+ static uint16_t ip_checksum(void *d, int c)
+ {
+       uint32_t sum = 0xffff;
+@@ -30,7 +35,7 @@ static uint16_t ip_checksum(void *d, int
+       }
+ 
+       if (c)
+-              sum += htons(*((uint8_t *)p) << 8);
++              sum += checksum_extend_byte(*((uint8_t *)p));
+ 
+       while (sum > 0xffff)
+               sum = (sum & 0xffff) + (sum >> 16);
+@@ -180,10 +185,12 @@ static int xlate_payload_4to6(struct pkt
+               cksum = ones_add(p->icmp->cksum, cksum);
+               if (p->icmp->type == 8) {
+                       p->icmp->type = 128;
+-                      p->icmp->cksum = ones_add(cksum, ~(128 - 8));
++                      p->icmp->cksum = ones_add(cksum,
++                                              ~checksum_extend_byte(128 - 8));
+               } else {
+                       p->icmp->type = 129;
+-                      p->icmp->cksum = ones_add(cksum, ~(129 - 0));
++                      p->icmp->cksum = ones_add(cksum,
++                                              ~checksum_extend_byte(129 - 0));
+               }
+               return 0;
+       case 17:
+@@ -668,10 +675,12 @@ static int xlate_payload_6to4(struct pkt
+               cksum = ones_add(p->icmp->cksum, cksum);
+               if (p->icmp->type == 128) {
+                       p->icmp->type = 8;
+-                      p->icmp->cksum = ones_add(cksum, 128 - 8);
++                      p->icmp->cksum = ones_add(cksum,
++                                              checksum_extend_byte(128 - 8));
+               } else {
+                       p->icmp->type = 0;
+-                      p->icmp->cksum = ones_add(cksum, 129 - 0);
++                      p->icmp->cksum = ones_add(cksum,
++                                              checksum_extend_byte(129 - 0));
+               }
+               return 0;
+       case 17: