Hi,
This patch fixes a few bugs. The translator was assuming one interface was already allocated in `netif_list` when calling `init_ifs` during startup, and used it to configure the loopback interface [1]. That was possibly true in the past but after upgrading liblwip I found `netif_list` is always null at the first call to `init_ifs`. That breaks fsysopts, the loopback interface and DHCP. fsysopts is broken only when the translator is started without parameters. When that happens, `netif_list` remains null after `init_ifs` finished. Because of that, a call to fsysopts tries to initialize the stack again instead of reconfiguring it [2]. That's linked to the second problem, the lack of loopback interface. `parse_opt` at [2] assumes that a correctly initialized stack will at least have one configured interface, the loopback one. And `init_ifs` only configures it when there's a single netif allocated at `netif_list`, that condition is not met if `netif_list` arrives null. Finally, DHCP fails on lwip if the translator is installed without parameters, like pfinet is: $ showtrans /servers/socket/2 /hurd/pfinet -6 /servers/socket/26 The DHCP client calls fsysopts on the translator [3]. So when installed without parameters, this call to fsysopts tries to initialize the stack again and crashes. This simple patch fixes the problems. --- [1] https://git.savannah.gnu.org/cgit/hurd/hurd.git/tree/lwip/lwip-util.c#n155 [2] https://git.savannah.gnu.org/cgit/hurd/hurd.git/tree/lwip/options.c#n266 [3] https://salsa.debian.org/debian/isc-dhcp/-/blob/master/debian/dhclient-script.hurd#L184
