* slirp: Can I get IPv6-only DHCP working?
@ 2022-08-25 22:38 Peter Delevoryas
2022-08-25 22:56 ` Samuel Thibault
0 siblings, 1 reply; 5+ messages in thread
From: Peter Delevoryas @ 2022-08-25 22:38 UTC (permalink / raw)
Cc: qemu-arm, qemu-devel, clg, samuel.thibault, garnermic, patrick, zhdaniel
I'm having a hard time figuring this out from looking at the code and the
user-level help options.
It seems like there's support for an IPv6 dns proxy, and there's literally a
file called "dhcpv6.c" in slirp, but it has a comment saying it only supports
whatever is necessary for TFTP network boot I guess. Maybe there's no support
then? I'm interested in adding it, if that's the case.
Thanks,
Peter
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: slirp: Can I get IPv6-only DHCP working?
2022-08-25 22:38 slirp: Can I get IPv6-only DHCP working? Peter Delevoryas
@ 2022-08-25 22:56 ` Samuel Thibault
2022-08-25 23:15 ` Peter Delevoryas
0 siblings, 1 reply; 5+ messages in thread
From: Samuel Thibault @ 2022-08-25 22:56 UTC (permalink / raw)
To: Peter Delevoryas; +Cc: qemu-arm, qemu-devel, clg, garnermic, patrick, zhdaniel
Hello,
Peter Delevoryas, le jeu. 25 août 2022 15:38:53 -0700, a ecrit:
> It seems like there's support for an IPv6 dns proxy, and there's literally a
> file called "dhcpv6.c" in slirp, but it has a comment saying it only supports
> whatever is necessary for TFTP network boot I guess.
For which DNS support is welcome :)
> Maybe there's no support then?
It seems there is:
if (ri.want_dns) {
*resp++ = OPTION_DNS_SERVERS >> 8; /* option-code high byte */
*resp++ = OPTION_DNS_SERVERS; /* option-code low byte */
*resp++ = 0; /* option-len high byte */
*resp++ = 16; /* option-len low byte */
memcpy(resp, &slirp->vnameserver_addr6, 16);
resp += 16;
}
Samuel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: slirp: Can I get IPv6-only DHCP working?
2022-08-25 22:56 ` Samuel Thibault
@ 2022-08-25 23:15 ` Peter Delevoryas
2022-08-25 23:20 ` Samuel Thibault
2022-08-26 7:21 ` Thomas Huth
0 siblings, 2 replies; 5+ messages in thread
From: Peter Delevoryas @ 2022-08-25 23:15 UTC (permalink / raw)
To: Samuel Thibault; +Cc: qemu-arm, qemu-devel, clg, garnermic, patrick, zhdaniel
On Fri, Aug 26, 2022 at 12:56:10AM +0200, Samuel Thibault wrote:
> Hello,
>
> Peter Delevoryas, le jeu. 25 août 2022 15:38:53 -0700, a ecrit:
> > It seems like there's support for an IPv6 dns proxy, and there's literally a
> > file called "dhcpv6.c" in slirp, but it has a comment saying it only supports
> > whatever is necessary for TFTP network boot I guess.
>
> For which DNS support is welcome :)
>
> > Maybe there's no support then?
>
> It seems there is:
>
> if (ri.want_dns) {
> *resp++ = OPTION_DNS_SERVERS >> 8; /* option-code high byte */
> *resp++ = OPTION_DNS_SERVERS; /* option-code low byte */
> *resp++ = 0; /* option-len high byte */
> *resp++ = 16; /* option-len low byte */
> memcpy(resp, &slirp->vnameserver_addr6, 16);
> resp += 16;
> }
Well, that's great, but actually I just care about whether slirp supports DHCPv6
address requests. Sorry if I didn't explain that properly.
My goal is to run:
qemu-system-arm -machine fby35-bmc -nographic -mtdblock image-bmc \
-net nic,model=ftgmac100,netdev=nic \
-netdev user,id=nic,hostfwd=::2222-:22
And then see that the BMC received an IPv6 address assignment.
But, slirp currently just supports IP address assignment through BOOTP? I
didn't realize that until looking a little closer at the code. But, since the
DHCPv6 hook "dhcpv6_input" is already there, maybe I can just get something
going through there? I suppose I might need some IPv6 NDP packets to work too,
to ssh through a hostfwd port.
root@bmc-oob:~# ifconfig eth0
eth0 Link encap:Ethernet HWaddr FA:CE:B0:02:20:22
inet addr:10.0.2.15 Bcast:10.0.2.255 Mask:255.255.255.0
inet6 addr: fec0::f8ce:b0ff:fe02:2022/64 Scope:Site
inet6 addr: fe80::f8ce:b0ff:fe02:2022/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:107 errors:0 dropped:0 overruns:0 frame:0
TX packets:136 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:13316 (13.0 KiB) TX bytes:10022 (9.7 KiB)
Interrupt:33
Anyways, I'll do some more investigation on my own, thanks!
Peter
>
> Samuel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: slirp: Can I get IPv6-only DHCP working?
2022-08-25 23:15 ` Peter Delevoryas
@ 2022-08-25 23:20 ` Samuel Thibault
2022-08-26 7:21 ` Thomas Huth
1 sibling, 0 replies; 5+ messages in thread
From: Samuel Thibault @ 2022-08-25 23:20 UTC (permalink / raw)
To: Peter Delevoryas; +Cc: qemu-arm, qemu-devel, clg, garnermic, patrick, zhdaniel
Peter Delevoryas, le jeu. 25 août 2022 16:15:26 -0700, a ecrit:
> On Fri, Aug 26, 2022 at 12:56:10AM +0200, Samuel Thibault wrote:
> > Peter Delevoryas, le jeu. 25 août 2022 15:38:53 -0700, a ecrit:
> > > It seems like there's support for an IPv6 dns proxy, and there's literally a
> > > file called "dhcpv6.c" in slirp, but it has a comment saying it only supports
> > > whatever is necessary for TFTP network boot I guess.
> >
> > For which DNS support is welcome :)
> >
> > > Maybe there's no support then?
> >
> > It seems there is:
> >
> > if (ri.want_dns) {
> > *resp++ = OPTION_DNS_SERVERS >> 8; /* option-code high byte */
> > *resp++ = OPTION_DNS_SERVERS; /* option-code low byte */
> > *resp++ = 0; /* option-len high byte */
> > *resp++ = 16; /* option-len low byte */
> > memcpy(resp, &slirp->vnameserver_addr6, 16);
> > resp += 16;
> > }
>
> Well, that's great, but actually I just care about whether slirp supports DHCPv6
> address requests. Sorry if I didn't explain that properly.
Ah. It doesn't seem to indeed.
> since the DHCPv6 hook "dhcpv6_input" is already there, maybe I can
> just get something going through there?
Probably.
Samuel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: slirp: Can I get IPv6-only DHCP working?
2022-08-25 23:15 ` Peter Delevoryas
2022-08-25 23:20 ` Samuel Thibault
@ 2022-08-26 7:21 ` Thomas Huth
1 sibling, 0 replies; 5+ messages in thread
From: Thomas Huth @ 2022-08-26 7:21 UTC (permalink / raw)
To: qemu-devel
On 26/08/2022 01.15, Peter Delevoryas wrote:
> On Fri, Aug 26, 2022 at 12:56:10AM +0200, Samuel Thibault wrote:
>> Hello,
>>
>> Peter Delevoryas, le jeu. 25 août 2022 15:38:53 -0700, a ecrit:
>>> It seems like there's support for an IPv6 dns proxy, and there's literally a
>>> file called "dhcpv6.c" in slirp, but it has a comment saying it only supports
>>> whatever is necessary for TFTP network boot I guess.
>>
>> For which DNS support is welcome :)
>>
>>> Maybe there's no support then?
>>
>> It seems there is:
>>
>> if (ri.want_dns) {
>> *resp++ = OPTION_DNS_SERVERS >> 8; /* option-code high byte */
>> *resp++ = OPTION_DNS_SERVERS; /* option-code low byte */
>> *resp++ = 0; /* option-len high byte */
>> *resp++ = 16; /* option-len low byte */
>> memcpy(resp, &slirp->vnameserver_addr6, 16);
>> resp += 16;
>> }
>
> Well, that's great, but actually I just care about whether slirp supports DHCPv6
> address requests. Sorry if I didn't explain that properly.
>
> My goal is to run:
>
> qemu-system-arm -machine fby35-bmc -nographic -mtdblock image-bmc \
> -net nic,model=ftgmac100,netdev=nic \
> -netdev user,id=nic,hostfwd=::2222-:22
>
> And then see that the BMC received an IPv6 address assignment.
>
> But, slirp currently just supports IP address assignment through BOOTP? I
> didn't realize that until looking a little closer at the code.
No, slirp support "IPv6 *stateless* address assignment" (if you haven't
heard about that before, I suggest to google it). That means that IPv6
addresses are not administered by a DHCP server, but that each client can
built its own IPv6 address. It basically works like this (don't quote me on
that, it's been a while since I worked with this stuff): Once the network
interface of the client gets activated, the OS creates a link-local IPv6
that can be only used for activating on the link (based on the MAC address).
It then uses this address for sending a "router solicitation" message, and
if there is a router on the link, it replies with a "router advertisment"
that contains a routable prefix. The client then can take this prefix to
form a unique IPv6 address and assign it to its interface. QEMU/slirp
support this way of address assignment, see ndp_send_na() in ip6_icmp.c.
So if your BMC code supports stateless IPv6 address (it certainly should),
you should be fine already).
HTH,
Thomas
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-08-26 7:29 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-25 22:38 slirp: Can I get IPv6-only DHCP working? Peter Delevoryas
2022-08-25 22:56 ` Samuel Thibault
2022-08-25 23:15 ` Peter Delevoryas
2022-08-25 23:20 ` Samuel Thibault
2022-08-26 7:21 ` Thomas Huth
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