include/coap2/pdu.h:
src/pdu.c:
tests/test_pdu.c:
Change parameter max_delta to max_opt to better reflect actual usage.
include/coap2/pdu.h:
src/pdu.c:
Remove unneeded COAP_OPT_LONG and COAP_OPT_END definitions.
Remove unused function coap_add_option_later().
src/pdu.c:
Update coap_pdu_parse_opt() to sanity check the valid lengths of all the
known options.
src/coap_io_lwip.c:
src/net.c:
Ignore packets < 4 bytes
Send back a RST for UDP/DTLS if malformed PDU.
src/option.c:
Clean up coap_option_filter_get() documentation.