dhcpcd-discuss

I've had a look at the patches we apply on top of upstream dhcpcd, and this
one is likely to be the culprit:

--- a/if.c
+++ b/if.c
@@ -534,7 +534,7 @@
         /* We reserve the 100 range for virtual interfaces, if and when
          * we can work them out. */
         ifp->metric = 200 + ifp->index;
-        if (if_getssid(ifp) != -1) {
+        if (if_getssid(ifp) != -1 || *ifp->name == 'w') {
             ifp->wireless = 1;
             ifp->metric += 100;
         }

On Thu, May 24, 2018 at 5:42 AM, JED <John@xxxxxxxxxxxxx> wrote:

> Hi, Jeremy. I had the same problem except it worked with 6.11.5 until I
> did apt-get upgrade and THEN it started to fail, still with 6.11.5. I never
> did figure out what changed to break it.
>
> What I did to resolve the issue is a workaround on a later version so I
> had RPi 3 B+ support. I went back to the /etc/network/interfaces
> configuration method and turned off dhcpcd. My GUESS is that dhcpcd is
> "waiting for carrier" because when I send it "dhcpcd -n wwan0" it again
> says "waiting for carrier" but the "interfaces" method SEEMS to just look
> for something else and its dhcp does the job, looking at the interface
> every 5 minutes and completes the dhcp so that ifconfig wwan0 shows the
> correct stuff that modem manager logged when the modem was connected. From
> then on, everything works great. Also, I can issue a command and make it
> happen without waiting for the 5 minutes.
>
> I've just come to this conclusion and NEVER asked Roy about it since we
> exchanged messages early last month, so he's not had a chance before to
> comment on my Wild A** Guess.
>
> I'm in the North Woods(tm) planting 1,000 pine trees and can't access the
> "whatIdid" file on that particular RPi from here since it's powered down,
> so I can't give you specifics of my configuration files or the commands
> that I use to speed things up. They do work on my latest Raspbian copy that
> started with a 2018-04-18-raspbian-stretch download. I'll be home this
> weekend and if Roy hasn't helped by then I'll send you what works for me.
>
> On 5/23/2018 7:05 PM, Jeremy K wrote:
>
>> I'm running Raspbian on the Raspberry Pi and have been encountering DHCP
>> issues with my USB 3G modem.
>>
>> The previous discussion for this issue is here
>> https://github.com/raspberrypi/linux/issues/2544, but to summarise,
>> dhcpcd 6.10.1 works as expected, but dhcpcd 6.11.5 does not.
>>
>> The modem driver (sierra_net) exposes a wwan0 interface, and on dhcpcd
>> 6.10.1, the interface successfully gets the IPv4 address and the interface
>> works as expected.
>>
>> Using dhcpcd 6.11.5, the wwan0 interface does not get an IP address, so I
>> can't use it. If I downgrade back to 6.10.1, then the interface gets the IP
>> address and starts working again.
>>
>> Here is the syslog snippet using 6.10.1 (good)
>>
>> |Sep 7 15:54:40 raspberrypi dhcpcd[250]: wwan0: waiting for carrier Sep 7
>> 15:54:40 raspberrypi kernel: [ 21.042350] IPv6: ADDRCONF(NETDEV_UP): wwan0:
>> link is not ready Sep 7 15:54:41 raspberrypi systemd[1]: Started Raise
>> network interfaces. Sep 7 15:54:42 raspberrypi kernel: [ 22.660424] IPv6:
>> ADDRCONF(NETDEV_CHANGE): wwan0: link becomes ready Sep 7 15:54:42
>> raspberrypi dhcpcd[250]: wwan0: carrier acquired Sep 7 15:54:42 raspberrypi
>> dhcpcd[250]: wwan0: adding address fe80::1e09:995:5f42:fa48 Sep 7 15:54:43
>> raspberrypi dhcpcd[250]: DUID 00:01:00:01:21:44:28:43:26:46:ee:43:01:07
>> Sep 7 15:54:43 raspberrypi dhcpcd[250]: wwan0: IAID ee:43:01:07 Sep 7
>> 15:54:43 raspberrypi dhcpcd[250]: wwan0: soliciting a DHCP lease Sep 7
>> 15:54:43 raspberrypi dhcpcd[250]: wwan0: soliciting an IPv6 router Sep 7
>> 15:54:43 raspberrypi dhcpcd[250]: wwan0: offered 100.113.23.172 from
>> 100.113.23.253 Sep 7 15:54:43 raspberrypi dhcpcd[250]: wwan0: probing
>> address 100.113.23.172/32 <http://100.113.23.172/32>|
>>
>> and the same for 6.11.5 (bad):
>>
>> |Nov 29 02:37:27 raspberrypi dhcpcd[238]: wwan0: waiting for carrier Nov
>> 29 02:37:27 raspberrypi dhcpcd[238]: wwan0: carrier acquired Nov 29
>> 02:37:27 raspberrypi dhcpcd[238]: wwan0: IAID 17:fa:01:07 Nov 29 02:37:27
>> raspberrypi dhcpcd[238]: wwan0: adding address fe80::3cc3:cfbd:f6e4:82ec
>> Nov 29 02:37:27 raspberrypi dhcpcd[238]: wwan0: carrier lost Nov 29
>> 02:37:27 raspberrypi dhcpcd[238]: wwan0: deleting address
>> fe80::3cc3:cfbd:f6e4:82ec |
>>
>>
>> Can anyone help me to figure out why 6.11.5 isn't working as expected,
>> and if there is a configuration I can change to resolve the issue?
>>
>>
>> Regards,
>>
>> Jeremy
>>
>>
>