[PATCH] added ipv6_dst_lookup_flow define for VZ7 kernels

[Benedikt Braunger]

This patch adds an additional check for OpenVZ / Virtuozzo 7 custom
kernels to ensure ipv6_dst_lookup_flow is defined.
It also splits the very long version checking into multiple lines for
better reading.

Signed-off-by: Benedikt Braunger <b.braunger at syseleven.de>
---
Since the error mentioned in "Wireguard DKMS build on OpenVZ 7" still
occures, I searched for a way to check if the module is compiled on 
a VZ kernel. This patch works for me, I tested on Virtuozzo 7 and 
plain CentOS 7. Can compile on both without error and the module is
loadable.
Probably Virtuozzo will backuport ipv6_dst_lookup_flow some day but
they can't (or don't want to) tell me when.
If so one can compare VZVERSION to the current one to ensure the definition
for older verions.

 src/compat/compat.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/compat/compat.h b/src/compat/compat.h
index 3e8e005..7700e7b 100644
--- a/src/compat/compat.h
+++ b/src/compat/compat.h
@@ -91,7 +91,13 @@
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0) && LINUX_VERSION_CODE >= KERNEL_VERSION(3, 16, 83)
 #define ipv6_dst_lookup_flow(a, b, c, d) ipv6_dst_lookup_flow(b, c, d)
-#elif (LINUX_VERSION_CODE < KERNEL_VERSION(5, 4, 5) && LINUX_VERSION_CODE >= KERNEL_VERSION(5, 4, 0)) || (LINUX_VERSION_CODE < KERNEL_VERSION(5, 3, 18) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 20, 0) && !defined(ISUBUNTU1904)) || (!defined(ISRHEL8) && !defined(ISDEBIAN) && !defined(ISUBUNTU1804) && LINUX_VERSION_CODE < KERNEL_VERSION(4, 19, 119) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0)) || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 181) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0)) || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 9, 224) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)) || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 224) && !defined(ISUBUNTU1604) && !defined(ISRHEL7))
+#elif (LINUX_VERSION_CODE < KERNEL_VERSION(5, 4, 5) && LINUX_VERSION_CODE >= KERNEL_VERSION(5, 4, 0))\
+  || (LINUX_VERSION_CODE < KERNEL_VERSION(5, 3, 18) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 20, 0) && !defined(ISUBUNTU1904))\
+  || (!defined(ISRHEL8) && !defined(ISDEBIAN) && !defined(ISUBUNTU1804) && LINUX_VERSION_CODE < KERNEL_VERSION(4, 19, 119) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0))\
+  || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 181) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 10, 0))\
+  || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 9, 224) && LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0))\
+  || (LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 224) && !defined(ISUBUNTU1604) && !defined(ISRHEL7))\
+  || (LINUX_VERSION_CODE == KERNEL_VERSION(3, 10, 0) && defined(ISRHEL7) && defined(VZVERSION))
 #define ipv6_dst_lookup_flow(a, b, c, d) ipv6_dst_lookup(a, b, &dst, c) + (void *)0 ?: dst
 #endif
 
-- 
2.25.1