Re: [PATCH net-next 2/2] bpf: support ipv6 for bpf_skb_{set,get}_tunnel_key

On Mon, Jan 11, 2016 at 01:16:39AM +0100, Daniel Borkmann wrote:

After IPv6 support has recently been added to metadata dst and related
encaps, add support for populating/reading it from an eBPF program.

Commit d3aa45ce6b ("bpf: add helpers to access tunnel metadata") started
with initial IPv4-only support back then (due to IPv6 metadata support
not being available yet).

To stay compatible with older programs, we need to test for the passed
structure size. Also TOS and TTL support from the ip_tunnel_info key has
been added. Tested with vxlan devs in collect meta data mode with IPv4,
IPv6 and in compat mode over different network namespaces.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

...

 struct bpf_tunnel_key {
 	__u32 tunnel_id;
-	__u32 remote_ipv4;
+	union {
+		__u32 remote_ipv4;
+		__u32 remote_ipv6[4];
+	};
+	__u8 tunnel_tos;
+	__u8 tunnel_ttl;
 };

Acked-by: Alexei Starovoitov <ast@kernel.org>

was hoping that you would mention that people should upgrade
their llvm to 3.7 release or later, since old pre-release
had a bug when dealing with such structs and some
'lazy' folks may still be running some old version ;)

btw, three minor bugs were fixed after 3.7 was released.
llvm 3.7.1 and 3.8 have no known issues in bpf backend.