* espconn: remove unused espconn code, take 1
This is the easiest part of https://github.com/nodemcu/nodemcu-firmware/issues/3004 .
It removes a bunch of functions that were never called in our tree.
* espconn: De-orbit espconn_gethostbyname
Further work on https://github.com/nodemcu/nodemcu-firmware/issues/3004
While here, remove `mqtt`'s charming DNS-retry logic (which is neither
shared with nor duplicated in other modules) and update its :connect()
return value behavior and documentation.
* espconn: remove scary global pktinfo
A write-only global! How about that.
* net: remove deprecated methods
All the TLS stuff moved over there a long time ago, and
net_createUDPSocket should just do what it says on the tin.
* espconn_secure: remove ESPCONN_SERVER support
We can barely function as a TLS client; being a TLS server seems like a
real stretch. This code was never called from Lua anyway.
* espconn_secure: more code removal
* espconn_secure: simplify ssl options structure
There is nothing "ssl_packet" about this structure. Get rid of the
terrifying "pbuffer" pointer.
Squash two structure types together and eliminate an unused field.
* espconn_secure: refactor mbedtls_msg_info_load
Split out espconn_mbedtls_parse, which we can use as part of our effort
towards addressing https://github.com/nodemcu/nodemcu-firmware/issues/3032
* espconn_secure: introduce TLS cert/key callbacks
The new feature part of https://github.com/nodemcu/nodemcu-firmware/issues/3032
Subsequent work will remove the old mechanism.
* tls: add deprecation warnings
* luacheck: net.ifinfo is a thing now
* tls: remove use of espconn->reverse
* mqtt: stop using espconn->reverse
Instead, just place the espconn structure itself at the top of the user
data. This enlarges the structure somewhat but removes one more layer
of dynamic heap usage and NULL checks.
While here, simplify the code a bit.
* mqtt: remove redundant pointer to connect_info
Everywhere we have the mqtt_state_t we also have the lmqtt_userdata.
* mqtt: doc fixes
* mqtt: note bug
* tls: allow :on(...,nil) to unregister a callback
* mqtt: expose "connfail" callback via :on()
This makes it just like all the other callbacks in the module and is a
revision of behavior called out in
https://github.com/nodemcu/nodemcu-firmware/pull/2967
* mqtt: clarify when puback callback fires
* mqtt: Don't reference stack buffers from the heap
The confusingly-named "mqtt_connection_t" object is just a triple of
- a serialized mqtt message pointer and length
- a buffer pointer (to which the above can be written)
- a message identifier
The last of these must be passed around the mqtt state machine, but the
first two are very local and the buffer is always sourced from the C
stack. Unfortunately, because the entire structure is persisted in the
heap, some callers assume that they can always use the structure without
reinitialization (see mqtt_socket_close), which will trash the C stack.
Sever the pairing between message id and local state, punt the local
state entirely out of the heap, and rename things to be less confusing.
We just don't have the memory to be a real TLS client on the 8266. Put
that in a big box and point at it from the http and mqtt modules; others
may also wish to give reference.
* mqtt:connect() secure parameter should be boolean
Continue to honor the old 0/1 values, but make them undocumented and add
a deprecation warning to the code and docs. Eventually, this should go
away.
* mqtt: rip out deprecated autoreconnect
* mqtt: expose all the callbacks via :on