RTA_TABLE undeclared (for kernel 2.6.17.4)

[Arie0510]

When compiling OpenVPN 2.5.0 for an old Readynas sparc with linux 2.6.17.4 I received the error below:

networking_sitnl.c: In function `sitnl_route_set':
networking_sitnl.c:873: error: `RTA_TABLE' undeclared (first use in this function)
networking_sitnl.c:873: error: (Each undeclared identifier is reported only once
networking_sitnl.c:873: error: for each function it appears in.)

Googling around learned that RTA_TABLE was introduced in kernel 2.6.19 which could explain this error.

[Gert Döring]

As a workaround, you can always build with configure --enable-iproute2 which will make it fall back to using the "ip" command for ifconfig/route. Which should hopefully be available.

As for RTA_TABLE and if we can handle this in a useful way "if missing" I pass on the ticket to ordex. He knows sitnl things :-)

[Antonio Quartulli]

In my opinion this is not something we can really check at build time.
There are tons of constants that do not exist on "$some old kernel" and we can't check for all of them.

One easy approach would be to check the kernel version currently running on the system, but we may have backports or we may be building for another host.

Since I don't expect many people to be running kernels <2.6.19, I'd rather leave this as it is and, like Gert said, rather point them to --enable-iproute2.