under load, writing packet sizes to the socket that are normally fine
can do partial writes, eg asking to write 4096 may only take 2800 of
it and return 2800 from the actual send.
Until now lws assumed that if it was safe to send, it could take any
size buffer, that's not the case under load.
This patch changes lws_write to return the amount actually taken...
that and the meaning of it becomes tricky when dealing with
compressed links, the amount taken and the amount sent differ. Also
there is no way to recover at the moment from a protocol-encoded
frame only being partially accepted... however for http file send
content it can and does recover now.
Small frames don't have to take any care about it but large atomic
sends (> 2K) have been seen to fail under load.
Signed-off-by: Andy Green <andy.green@linaro.org>
The function has a logical problem when the size of the requested
allocation is 0, it will return NULL which is overloaded as
failure.
Actually the whole function is evil as an api, this patch moves
it out of the public API space and fixes it to return 0 for
success or 1 for fail. Private code does not need to to return
wsi->user_space and public code should only get that from the
callback as discussed on trac recently.
Thanks to Edwin for debugging the problem.
Reported-by: Edwin van den Oetelaar <oetelaar.automatisering@gmail.com>
Signed-off-by: Andy Green <andy.green@linaro.org>
The two cases where I introduced snprintf are either already
safe for buffer overflow or can be made so with one extra
statement, allowing sprintf.
Signed-off-by: Andy Green <andy.green@linaro.org>
This brings the library sources into compliance with checkpatch
style except for three or four exceptions like WIN32 related stuff
and one long string constant I don't want to break into multiple
sprintf calls.
There should be no functional or compilability change from all
this (hopefully).
Signed-off-by: Andy Green <andy.green@linaro.org>
This big patch replaces the malloc / realloc per header
approach used until now with a single three-level struct
that gets malloc'd during the header union phase and freed
in one go when we transition to a different union phase.
It's more expensive in that we malloc a bit more than 4Kbytes,
but it's a lot cheaper in terms of malloc, frees, heap fragmentation,
no reallocs, nothing to configure. It also moves from arrays of
pointers (8 bytes on x86_64) to unsigned short offsets into the
data array, (2 bytes on all platforms).
The 3-level thing is all in one struct
- array indexed by the header enum, pointing to first "fragment" index
(ie, header type to fragment lookup, or 0 for none)
- array of fragments indexes, enough for 2 x the number of known headers
(fragment array... note that fragments can point to a "next"
fragment if the same header is spread across multiple entries)
- linear char array where the known header payload gets written
(fragments point into null-terminated strings stored in here,
only the known header content is stored)
http headers can legally be split over multiple headers of the same
name which should be concatenated. This scheme does not linearly
conatenate them but uses a linked list in the fragment structs to
link them. There are apis to get the total length and copy out a
linear, concatenated version to a buffer.
Signed-off-by: Andy Green <andy.green@linaro.org>
A new protocol member is defined that controls the size of rx
buffer allocation per connection. For compatibility 0 size
allocates 4096, but you should adapt your protocol definition
array in the user code to declare an appropriate value.
See the changelog for more detail.
The advantage is the rx frame buffer size is now tailored to
what is expected from the protocol, rather than being fixed
to a default of 4096. If your protocol only sends frames of
a dozen bytes this allows you to only allocate an rx frame
buffer of the same size.
For example the per-connection allocation (excluding headers)
for the test server fell from ~4500 to < 750 bytes with this.
Signed-off-by: Andy Green <andy.green@linaro.org>
This reduces the size of struct libwebscocket from 4840 to 4552
on x86_64
There are also big benefits on malloc pool fragmentation and
allocation, the header allocations only exist between the first
peer communication and websocket connection establishment for
both server and client.
Signed-off-by: Andy Green <andy.green@linaro.org>
Large chunks of struct libwebsocket members actually have a mutually
exclusive lifecycle, eg, once the http headers are finished they sit
there unused until the instance is destroyed.
This makes a big improvement in memory efficiency by making four
categories of member: always needed, needed for header processing,
needed for http processing, and needed for ws processing. The last
three are mutually exclusive and bound into a union inside the wsi.
Care needs taking now at "union transitions", although we zeroed down
the struct at init, the other union siblings have been writing the
same memory by the time later member siblings start to use it. So
it must be cleared down appropriately when we cross from one
mutually-exclusive use to another.
Signed-off-by: Andy Green <andy.green@linaro.org>
Since v13 was defined as the released ietf version the older versions
are deprecated. This patch strips out everything to do with the older
versions and gets rid of the option to send stuff unmasked.
The in-tree md5 implementation is then also deleted as nothing needs
it any more, 1280 loc are shed in all
Signed-off-by: Andy Green <andy.green@linaro.org>
The new --without-extensions config flag completely removes all code
and data related to extensions from the build throughout the library
when given.
Signed-off-by: Andy Green <andy.green@linaro.org>
Move server-only stuff into their own files and make building
that depend on not having --without-server on the configure
Make fragments in other places conditional as well
Remove client-related members from struct libwebscket when
building LWS_NO_CLIENT
Apps:
normal: build test server, client, fraggle, ping
--without-client: build test server
--without-server: build test client, ping
Signed-off-by: Andy Green <andy.green@linaro.org>
