kern/177362: [netinet] [patch] Wrong control used to return TOS

[Michael Tuexen]

The following reply was made to PR kern/177362; it has been noted by GNATS.

From: Michael Tuexen <tuexen at freebsd.org>
To: Mark Andrews <marka at isc.org>
Cc: bug-followup at FreeBSD.org
Subject: Re: kern/177362: [netinet] [patch] Wrong control used to return TOS
Date: Wed, 27 Mar 2013 13:16:30 +0100

 On Mar 27, 2013, at 12:54 PM, Mark Andrews wrote:
 
 >=20
 > In message <25EB2335-645C-42ED-B90A-6D07A33280DB at freebsd.org>, Michael =
 Tuexen w
 > rites:
 >> It was not done by accident. The returned cmsg_type is IP_RECVTOS =
 instead=20
 >> of IP_TOS to keep it consistent with the handling of the IP_RECVTTL =
 socket=20
 >> option.
 >> I found it more important to be consistent within the same protocol =
 family
 >> than across different ones.
 >> I think that unfortunately IP_RECVTOS is not defined in any standard.
 >>=20
 >> Best regards
 >> Michael
 >=20
 > And Linux uses IP_TOS to return the value.
 ... which is consistent with the IP_RECVTTL socket option on Linux, =
 where it returns
 a cmsg with cmsg_type IP_TTL, which is also different from how this is =
 handled in
 FreeBSD.
 
 I think Solaris uses for IPv4 socket options the same cmsg_type
 as the optname for the socket option to enable the reception of the =
 cmsg.
 
 So it looks like there is no standard here, Linux, FreeBSD and Solaris
 are each consistent with itself, but Linux does it differently from
 FreeBSD and Solaris.
 
 Best regards
 Michael
 >=20
 > --=20
 > Mark Andrews, ISC
 > 1 Seymour St., Dundas Valley, NSW 2117, Australia
 > PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org
 >=20