mirror of
https://github.com/warmcat/libwebsockets.git
synced 2025-03-23 00:00:06 +01:00
6f520a5195
Libwebsockets is fundamentally singlethreaded... the existence of the fork and broadcast support, especially in the sample server is giving the wrong idea about how to use it. This replaces broadcast in the sample server with libwebsocket_callback_on_writable_all_protocol(). The whole idea of 'broadcast' is removed. All of the broadcast proxy stuff is removed: data must now be sent from the callback only. Doing othherwise is not reliable since the service loop may close the socket and free the wsi at any time, invalidating a wsi pointer held by another thread (don't do that!) Likewise the confirm_legit_wsi api added recently does not help the other thread case, since if the wsi has been freed dereferencing the wsi to study if it is legit or not will segfault in that case. So this is removed too. The overall effect is to push user code to only operate inside the protocol callbacks or external poll loops, ie, single thread context. Signed-off-by: Andy Green <andy.green@linaro.org>
233 lines
8.4 KiB
Text
233 lines
8.4 KiB
Text
Building the library and test apps
|
|
----------------------------------
|
|
|
|
You need to regenerate the autotools and libtoolize stuff for your system
|
|
|
|
$ ./autogen.sh
|
|
|
|
Then for a Fedora x86_86 box, the following config line was
|
|
needed:
|
|
|
|
./configure --prefix=/usr --libdir=/usr/lib64 --enable-openssl
|
|
|
|
For Apple systems, Christopher Baker reported that this is needed
|
|
(and I was told separately enabling openssl makes trouble somehow)
|
|
|
|
./configure CC="gcc -arch i386 -arch x86_64" CXX="g++ -arch i386 -arch
|
|
x86_64" CPP="gcc -E" CXXCPP="g++ -E" --enable-nofork
|
|
|
|
For mingw build, I did the following to get working build, ping test is
|
|
disabled when building this way
|
|
|
|
1) install mingw64_w32 compiler packages from Fedora
|
|
2) additionally install mingw64-zlib package
|
|
3) ./configure --prefix=/usr --enable-mingw --host=x86_64-w64-mingw32
|
|
4) make
|
|
|
|
For uClibc, you will likely need --enable-builtin-getifaddrs
|
|
|
|
For cross-building, here's an example using the Linaro ARM toolchain
|
|
|
|
./configure --prefix=/usr --host=arm-linux-gnueabi --without-client --without-extensions
|
|
|
|
you can build cross with client and extensions perfectly well, but
|
|
apart from the size shrink this has the nice characteristic that no
|
|
non-toolchain libraries are needed to build it.
|
|
|
|
|
|
otherwise if /usr/local/... and /usr/local/lib are OK then...
|
|
|
|
$ ./configure
|
|
$ make clean
|
|
$ make && sudo make install
|
|
$ libwebsockets-test-server
|
|
|
|
should be enough to get a test server listening on port 7861.
|
|
|
|
|
|
Configure script options
|
|
------------------------
|
|
|
|
There are several other possible configure options
|
|
|
|
--enable-libcrypto by default libwebsockets uses its own
|
|
built-in md5 and sha-1 implementation for
|
|
simplicity. However the libcrypto ones
|
|
may be faster, and in a distro context it
|
|
may be highly desirable to use a common
|
|
library implementation for ease of security
|
|
upgrades. Give this configure option
|
|
to disable the built-in ones and force use
|
|
of the libcrypto (part of openssl) ones.
|
|
|
|
--with-client-cert-dir=dir tells the client ssl support where to
|
|
look for trust certificates to validate
|
|
the remote certificate against.
|
|
|
|
--enable-noping Don't try to build the ping test app
|
|
It needs some unixy environment that
|
|
may choke in other build contexts, this
|
|
lets you cleanly stop it being built
|
|
|
|
--enable-builtin-getifaddrs if your libc lacks getifaddrs, you can build an
|
|
implementation into the library. By default your libc
|
|
one is used.
|
|
|
|
--without-testapps Just build the library not the test apps
|
|
|
|
--without-client Don't build the client part of the library nor the
|
|
test apps that need the client part. Useful to
|
|
minimize library footprint for embedded server-only
|
|
case
|
|
|
|
--without-server Don't build the server part of the library nor the
|
|
test apps that need the server part. Useful to
|
|
minimize library footprint for embedded client-only
|
|
case
|
|
|
|
--without-daemonize Don't build daemonize.c / lws_daemonize
|
|
|
|
--disable-debug Remove all debug logging below lwsl_notice in severity
|
|
from the code -- it's not just defeated from logging
|
|
but removed from compilation
|
|
|
|
--without-extensions Remove all code and data around protocol extensions.
|
|
This reduces the code footprint considerably but
|
|
you will lose extension features like compression.
|
|
However that may be irrelevant for embedded use and
|
|
the code / data size / speed improvements may be
|
|
critical.
|
|
|
|
|
|
Externally configurable important constants
|
|
-------------------------------------------
|
|
|
|
You can control these from configure by just setting them as commandline
|
|
args throgh CFLAGS, eg
|
|
|
|
./configure CFLAGS="-DLWS_MAX_ZLIB_CONN_BUFFER=8192"
|
|
|
|
|
|
They all have reasonable defaults usable for all use-cases except resource-
|
|
constrained, so you only need to take care about them if you want to tune them
|
|
to the amount of memory available.
|
|
|
|
- LWS_MAX_HEADER_NAME_LENGTH default 64: max characters in an HTTP header
|
|
name that libwebsockets can cope with
|
|
|
|
- LWS_MAX_HEADER_LEN default 4096: largest HTTP header value string length
|
|
libwebsockets can cope with
|
|
|
|
- LWS_INITIAL_HDR_ALLOC default 256: amount of memory to allocate initially,
|
|
tradeoff between taking too much and needless realloc
|
|
|
|
- LWS_ADDITIONAL_HDR_ALLOC default 64: how much to additionally realloc if
|
|
the header value string keeps coming
|
|
|
|
- MAX_USER_RX_BUFFER default 4096: max amount of user rx data to buffer at a
|
|
time and pass to user callback LWS_CALLBACK_RECEIVE or
|
|
LWS_CALLBACK_CLIENT_RECEIVE. Large frames are passed to the user callback
|
|
in chunks of this size. Tradeoff between per-connection static memory
|
|
allocation and if you expect to deal with large frames, how much you can
|
|
see at once which can affect efficiency.
|
|
|
|
- MAX_BROADCAST_PAYLOAD default 4096: largest amount of user tx data we can
|
|
broadcast at a time
|
|
|
|
- LWS_MAX_PROTOCOLS default 10: largest amount of different protocols the
|
|
server can serve
|
|
|
|
- LWS_MAX_EXTENSIONS_ACTIVE default 10: largest amount of extensions we can
|
|
choose to have active on one connection
|
|
|
|
- SPEC_LATEST_SUPPORTED default 13: only change if you want to remove support
|
|
for later protocol versions... unlikely
|
|
|
|
- AWAITING_TIMEOUT default 5: after this many seconds without a response, the
|
|
server will hang up on the client
|
|
|
|
- CIPHERS_LIST_STRING default "DEFAULT": SSL Cipher selection. It's advisable
|
|
to tweak the ciphers allowed to be negotiated on secure connections for
|
|
performance reasons, otherwise a slow algorithm may be selected by the two
|
|
endpoints and the server could expend most of its time just encrypting and
|
|
decrypting data, severely limiting the amount of messages it will be able to
|
|
handle per second. For example::
|
|
|
|
"RC4-MD5:RC4-SHA:AES128-SHA:AES256-SHA:HIGH:!DSS:!aNULL"
|
|
|
|
- SYSTEM_RANDOM_FILEPATH default "/dev/urandom": if your random device differs
|
|
you can set it here
|
|
|
|
- LWS_MAX_ZLIB_CONN_BUFFER maximum size a compression buffer is allowed to
|
|
grow to before closing the connection. Some limit is needed or any connecton
|
|
can exhaust all server memory by sending it 4G buffers full of zeros which the
|
|
server is expect to expand atomically. Default is 64KBytes.
|
|
|
|
- LWS_SOMAXCONN maximum number of pending connect requests the listening
|
|
socket can cope with. Default is SOMAXCONN. If you need to use synthetic
|
|
tests that just spam hundreds of connect requests at once without dropping
|
|
any, you can try messing with these as well as ulimit (see later)
|
|
(courtesy Edwin van der Oetelaar)
|
|
|
|
echo "2048 64512" > /proc/sys/net/ipv4/ip_local_port_range
|
|
echo "1" > /proc/sys/net/ipv4/tcp_tw_recycle
|
|
echo "1" > /proc/sys/net/ipv4/tcp_tw_reuse
|
|
echo "10" > /proc/sys/net/ipv4/tcp_fin_timeout
|
|
echo "65536" > /proc/sys/net/core/somaxconn
|
|
echo "65536" > /proc/sys/net/ipv4/tcp_max_syn_backlog
|
|
echo "262144" > /proc/sys/net/netfilter/nf_conntrack_max
|
|
|
|
|
|
Memory efficiency
|
|
-----------------
|
|
|
|
Update at 35f332bb46464feb87eb
|
|
|
|
Embedded server-only configuration without extensions (ie, no compression
|
|
on websocket connections), but with full v13 websocket features and http
|
|
server, built on ARM Cortex-A9:
|
|
|
|
./configure --without-client --without-extensions --disable-debug --enable-nofork --without-daemonize
|
|
|
|
.text .rodata .data .bss
|
|
11476 2664 288 4
|
|
|
|
Context Creation, 1024 fd limit[2]: 12288 (12 bytes per fd)
|
|
Per-connection [3]: 4400 bytes
|
|
|
|
|
|
This shows the impact of the major configuration with/without options at
|
|
13ba5bbc633ea962d46d using Ubuntu ARM on a PandaBoard ES.
|
|
|
|
These are accounting for static allocations from the library elf, there are
|
|
additional dynamic allocations via malloc
|
|
|
|
Static allocations, ARM9
|
|
.text .rodata .data .bss
|
|
All (no without) 35024 9940 336 4104
|
|
without client 25684 7144 336 4104
|
|
without client, exts 21652 6288 288 4104
|
|
without client, exts, debug[1] 19756 3768 288 4104
|
|
without server 30304 8160 336 4104
|
|
without server, exts 25382 7204 288 4104
|
|
without server, exts, debug[1] 23712 4256 288 4104
|
|
|
|
Dynamic allocations: ARM9 (32 bit)
|
|
|
|
Context Creation, 1024 fd limit[2] in ulimit: 12288 (12 bytes per fd)
|
|
Per-connection (excluding headers[3]): 8740
|
|
|
|
Dynamic allocations: x86_64 (64 bit)
|
|
|
|
Context Creation, 1024 fd limit[2] in ulimit: 16384 (16 bytes per fd)
|
|
Per-connection (excluding headers[3]): 9224
|
|
|
|
[1] --disable-debug only removes messages below lwsl_notice. Since that is
|
|
the default logging level the impact is not noticable, error, warn and notice
|
|
logs are all still there.
|
|
|
|
[2] 1024 fd per process is the default limit (set by ulimit) in at least Fedora
|
|
and Ubuntu.
|
|
|
|
[3] known headers are retained via additional mallocs for the lifetime of the
|
|
connection
|