inet: Add common IPv6 packet header macros

Adds commonly used IPv6 packet header macros similar to what is available
on NetBSD and FreeBSD in sys/netinet/ip6.h and Android in
libc/include/netinet/ip6.h

Usage example IPV6_VERSION_MASK and IPV6_VERSION:

    if ((ip6->ip6_vfc & IPV6_VERSION_MASK) == IPV6_VERSION)
        return true;

Usage example IPV6_FLOWINFO_MASK:

    ip6->ip6_flow = (flow & IPV6_FLOWINFO_MASK);

The relevant standard is RFC2460 (Internet Protocol, Version 6
Specification). It defines the Internet Protocol version (IPV6_VERSION)
and reduced the size of the flow label field from 24 to 20 bits
(IPV6_FLOWLABEL_MASK). The traffic class and flow label fields together
make up the flow information (IPV6_FLOWINFO_MASK).

Tested on x86_64 GNU/Linux

Signed-off-by: Dan Luedtke <danrl@google.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

0 files changed, 0 insertions, 0 deletions