Store a pointer to the options in the DHCPMessage struct, and pass
this together with an offset around, rather than a uint8_t**.
This avoids us having to (re)compute the pointer; and changes
dhcp_option_append from adjusting both the pointer to the next
option and the remaining size of the options, to just adjusting
the current offset.
This makes the code a bit simpler to follow IMHO, but there should
be no functional change.
Add an explicit stop state for the DHCP client so that the library
user can issue a stop at any time the callback has been called.
When returning from the callback, check also the stop state and
stop any further DHCP processing.
Also move the checking of it to the main message handler, rather than the
options parser.
Fix a bug, so we now drop the packet if any of the magic bytes don't match.
Before we used to only drop the packet if they were all wrong.
Tom Gundersen
Patrik Flykt