svn commit: r206452 - head/sys/netinet

[Alexander Leidinger]

Quoting Bruce Simpson <bms at incunabulum.net> (from Thu, 15 Apr 2010  
18:10:04 +0100):

> On 04/10/10 13:05, Bruce M Simpson wrote:
>> Log:
>>   Fix a few issues related to the legacy 4.4 BSD multicast APIs.
>>
>>   IPv4 addresses can and do change during normal operation. Testing by
>>   pfSense developers exposed an issue where OpenOSPFD was using the IPv4
>>   address to leave the OSPF link-scope multicast groups on a dynamic
>>   OpenVPN tun interface, rather than using RFC 3678 with the interface
>>   index, which won't be raced when the interface's addresses change.
>>
>
> I should point out that IP multicast is counter-intuitive in many  
> areas. It seems that knowledge of how to work with it effectively is  
> not that widespread. People who have a need to use it, often have  
> very specific requirements.
>
> IP multicast group membership is always scoped to physical links  
> [1]. The 4.4BSD API originally used the "primary IP address" to  
> identify each link. Unfortunately this is not a persistent  
> identifier, especially so in the use-case which had problems.

Is/was this the reason why multicast does not work in jails?

> In the updated API specified in RFC 3678, the primary key for  
> multicast memberships, changes to the interface index. routed(8) in  
> FreeBSD's SVN tree uses this new API; thanks to phk for reviewing  
> and testing my change.

Will this change make it possible to use multicast in jails now?

Bye,
Alexander.

-- 
Dentist, n.:
	A Prestidigitator who, putting metal in one's mouth,
	pulls coins out of one's pockets.
		-- Ambrose Bierce, "The Devil's Dictionary"

http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137