How to use dhcp relay over ipsec0/wwan0 with zero MAC address?
qingtao.cao.au at gmail.com
Tue Nov 24 00:31:38 UTC 2020
Hi Thomas and other DHCP ISC developers,
Good day! This is my very first attempt to contribute back to the DHCP ISC
community. How could I generate and send pull requests for
the git at gitlab.isc.org:isc-projects/dhcp.git repo properly?
Anyway, currently I attached my patchset to the following issue:
Looking forward to hearing from you, much appreciated!
On Thu, Nov 5, 2020 at 12:09 PM Qingtao <qingtao.cao.au at gmail.com> wrote:
> I am trying to use the dhcrelay on an ipsec0 interface that was built upon
> cellular modem interface, wwan0 for example. The problem I am running into
> is that, the QMI qmi_wwan.c kernel driver for the cellular modem works in
> the raw_ip mode and will setup wwanX relevant net_device with type ==
> ARPHRD_NONE and hard_header_len == 0, since the MAC address for wwan0 only
> makes sense for the host and not used on the USB link from the host to the
> cellular modem.
> Then the ipsec0 interface will inherit both the IP address and the MAC
> address, which will upset the dhcp relay daemon: in lpf.c get_hw_addr(),
> switch(sa->sa_family) case structure will thow out the following error:
> Unsupported device type 65534 for "ipsec0"
> The 65534 == 0xFFFE, or ARPHRD_NONE. I am wondering if it is feasible to
> change the get_hw_addr() to regard it as an normal case, for example:
> +@@ -522,6 +522,11 @@ get_hw_addr(const char *name, struct har
> + hw->hbuf = HTYPE_FDDI;
> + memcpy(&hw->hbuf, sa->sa_data, 6);
> + break;
> ++ case ARPHRD_NONE:
> ++ /* When the qmi_wwan.c kernel driver works in the
> ++ * raw_ip mode the length of MAC address is zero */
> ++ memset(hw, 0, sizeof(struct hardware));
> ++ break;
> + default:
> + log_fatal("Unsupported device type %ld for \"%s\"",
> + (long int)sa->sa_family, name);
> Would this work?
> Thanks in advance!
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