The helper function exec_user_callback executes within the context of an
lwIP C callback, and the user (Python) callback to be scheduled may want to
perform further TCP/IP actions, so the latter should be scheduled to run
outside the lwIP context (otherwise it's effectively a "hard IRQ" and such
callbacks have lots of restrictions).
If tcp_write returns ERR_MEM then it's not a fatal error but instead means
the caller should retry the write later on (and this is what lwIP's netconn
API does).
This fixes problems where a TCP send would raise OSError(ENOMEM) in
situations where the TCP/IP stack is under heavy load. See eg issues #1897
and #1971.
Setting MICROPY_PY_USSL and MICROPY_SSL_MBEDTLS at the Makefile-level will
now build mbedTLS from source and include it in the build, with the ussl
module using this TLS library. Extra settings like MBEDTLS_CONFIG_FILE may
need to be provided by a given port.
If a port wants to use its own mbedTLS library then it should not set
MICROPY_SSL_MBEDTLS at the Makefile-level but rather set it at the C level,
and provide the library as part of the build in its own way (see eg esp32
port).
In d5f0c87bb9 this call to tcp_poll() was
added to put a timeout on closing TCP sockets. But after calling
tcp_close() the PCB may be freed and therefore invalid, so tcp_poll() can
not be used at that point. As a fix this commit calls tcp_poll() before
closing the TCP PCB. If the PCB is subsequently closed and freed by
tcp_close() or tcp_abort() then the PCB will not be on any active list and
the callback will not be executed, which is the desired behaviour (the
_lwip_tcp_close_poll() callback only needs to be called if the PCB remains
active for longer than the timeout).
Commit 2848a613ac introduced a bug where
lwip_socket_free_incoming() accessed pcb.tcp->state after the PCB was
closed. The state may have changed due to that close call, or the PCB may
be freed and therefore invalid. This commit fixes that by calling
lwip_socket_free_incoming() before the PCB is closed.
For example: i2c.writevto(addr, (buf1, buf2)). This allows to efficiently
(wrt memory) write data composed of separate buffers, such as a command
followed by a large amount of data.
It consists of:
1. "do_handhake" param (default True) to wrap_socket(). If it's False,
handshake won't be performed by wrap_socket(), as it would be done in
blocking way normally. Instead, SSL socket can be set to non-blocking mode,
and handshake would be performed before the first read/write request (by
just returning EAGAIN to these requests, while instead reading/writing/
processing handshake over the connection). Unfortunately, axTLS doesn't
really support non-blocking handshake correctly. So, while framework for
this is implemented on MicroPython's module side, in case of axTLS, it
won't work reliably.
2. Implementation of .setblocking() method. It must be called on SSL socket
for blocking vs non-blocking operation to be handled correctly (for
example, it's not enough to wrap non-blocking socket with wrap_socket()
call - resulting SSL socket won't be itself non-blocking). Note that
.setblocking() propagates call to the underlying socket object, as
expected.
For this, add wrap_socket(do_handshake=False) param. CPython doesn't have
such a param at a module's global function, and at SSLContext.wrap_socket()
it has do_handshake_on_connect param, but that uselessly long.
Beyond that, make write() handle not just MBEDTLS_ERR_SSL_WANT_WRITE, but
also MBEDTLS_ERR_SSL_WANT_READ, as during handshake, write call may be
actually preempted by need to read next handshake message from peer.
Likewise, for read(). And even after the initial negotiation, situations
like that may happen e.g. with renegotiation. Both
MBEDTLS_ERR_SSL_WANT_READ and MBEDTLS_ERR_SSL_WANT_WRITE are however mapped
to the same None return code. The idea is that if the same read()/write()
method is called repeatedly, the progress will be made step by step anyway.
The caveat is if user wants to add the underlying socket to uselect.poll().
To be reliable, in this case, the socket should be polled for both POLL_IN
and POLL_OUT, as we don't know the actual expected direction. But that's
actually problematic. Consider for example that write() ends with
MBEDTLS_ERR_SSL_WANT_READ, but gets converted to None. We put the
underlying socket on pull using POLL_IN|POLL_OUT but that probably returns
immediately with POLL_OUT, as underlyings socket is writable. We call the
same ussl write() again, which again results in MBEDTLS_ERR_SSL_WANT_READ,
etc. We thus go into busy-loop.
So, the handling in this patch is temporary and needs fixing. But exact way
to fix it is not clear. One way is to provide explicit function for
handshake (CPython has do_handshake()), and let *that* return distinct
codes like WANT_READ/WANT_WRITE. But as mentioned above, past the initial
handshake, such situation may happen again with at least renegotiation. So
apparently, the only robust solution is to return "out of bound" special
sentinels like WANT_READ/WANT_WRITE from read()/write() directly. CPython
throws exceptions for these, but those are expensive to adopt that way for
efficiency-conscious implementation like MicroPython.
In CPython the random module is seeded differently on each import, and so
this new macro option MICROPY_PY_URANDOM_SEED_INIT_FUNC allows to implement
such a behaviour.
Since commit da938a83b5 the tcp_arg() that is
set for the new connection is the new connection itself, and the parent
listening socket is found in the pcb->connected entry.
Use uos.dupterm for REPL configuration of the main USB_VCP(0) stream on
dupterm slot 1, if USB is enabled. This means dupterm can also be used to
disable the boot REPL port if desired, via uos.dupterm(None, 1).
For efficiency this adds a simple hook to the global uos.dupterm code to
work with streams that are known to be native streams.
Some users of this module may require the LwIP stack to run at an elevated
priority, to protect against concurrency issues with processing done by the
underlying network interface. Since LwIP doesn't provide such protection
it must be done here (the other option is to run LwIP in a separate thread,
and use thread protection mechanisms, but that is a more heavyweight
solution).
The bug polling for readability was: if alloc==0 and tcp.item==NULL then
the code would incorrectly check tcp.array[iget] which is an invalid
dereference when alloc==0. This patch refactors the code to use a helper
function lwip_socket_incoming_array() to return the correct pointer for the
incomming connection array.
Fixes issue #4511.
As mentioned in #4450, `websocket` was experimental with a single intended
user, `webrepl`. Therefore, we'll make this change without a weak
link `websocket` -> `uwebsocket`.
Previously crypto-algorithms impl was included even if MICROPY_SSL_MBEDTLS
was in effect, thus we relied on the compiler/linker to cut out the unused
functions.
Python defines warnings as belonging to categories, where category is a
warning type (descending from exception type). This is useful, as e.g.
allows to disable warnings selectively and provide user-defined warning
types. So, implement this in MicroPython, except that categories are
represented just with strings. However, enough hooks are left to implement
categories differently per-port (e.g. as types), without need to patch each
and every usage.
This header is deprecated as of mbedtls 2.8.0, as shipped with Ubuntu
18.04. Leads to #warning which is promoted to error with uPy compile
options.
Note that the current version of mbedtls is 2.14 at the time of writing.
It's more robust to have the version defined statically in a header file,
rather than dynamically generating it via git using a git tag. In case
git doesn't exist, or a different source control tool is used, it's
important to still have the uPy version number available.
Damien George