huawei: refactor the connection and disconnection sequences in the bearer

We will now use a step-based state machine to handle the connection and
disconnection sequences. All the previous behaviour is kept, except for these
new things:

 * Instead of just subclassing the 'dialling' step in the 3GPP connection
   sequence, completely subclass the whole 3GPP connection sequence. We do this
   because we don't need to preconfigure PDP contexts with AT+CGDCONT before
   issuing ^NDISDUP.

 * Don't allow IP types other than IPv4. These modems work only with IPv4
   bearers.

 * Remove cancellation signal handler; not needed as we can check the status of
   the cancellation in every 1s timeout.

 * Removed the event source id handling for timeouts; timeouts are never
   cancelled here.

0 files changed, 0 insertions, 0 deletions