Re: [ECOS] Re: Does FreeBSD stack support multiple IP addresses?

["Lambrecht Jürgen" <J.Lambrecht@TELEVIC.com>]

On 02/19/2016 07:11 PM, Grant Edwards wrote:
> On 2016-02-19, Grant Edwards <grant.b.edwards@gmail.com> wrote:
>
>> Can one assign multiple IP addresses (on different subnets) to a
>> single interface when using the eCos FreeBSD network stack?
>>
>> I know modern BSD and Linux stacks all support that, but does the eCos
>> implementation?
> Some poking through the source doe and subsequent experimentation has
> answered my question in the affirmative.
>
> You use SIOCAIFADDR(_IN6) instead of SIOCASIFADDR and its brethren.
>
I had 2 problems to assign 2 IP addresses with different netmasks:
- To assign an IP address an set a netmask are 2 different ioctl calls. 
To set the netmask, you cannot specify for which IP address you set it. 
The code (current/src/sys/netinet/in.c) is written in such a way that 
the netmask is set on the last IP address you added on that interface. 
So that should be OK if you keep the correct order.
- It is only possible to assign a class A/B/C netmask. CIDR netmasks are 
not possible. I fixed current/src/sys/netinet/in.c for it, but I also 
adapted the ioctl to combine setting IP address and netmask in 1 call 
(so I cannot commit it back). Let me know if you want my fix.

Short answer: yes it is possible.

Kind regards,
Jürgen

P.S.: CIDR is possible in the freeBSD stack, it is only the ioctl in 
current/src/sys/netinet/in.c that is the limitation

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Jürgen Lambrecht
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