286cf4357a
Adapt the pt sul owner list to be an array, and define two different lists, one that acts like before and is the default for existing users, and another that has the ability to cooperate with systemwide suspend to restrict the interval spent suspended so that it will wake in time for the earliest thing on this wake-suspend sul list. Clean the api a bit and add lws_sul_cancel() that only needs the sul as the argument. Add a flag for client creation info to indicate that this client connection is important enough that, eg, validity checking it to detect silently dead connections should go on the wake-suspend sul list. That flag is exposed in secure streams policy so it can be added to a streamtype with "swake_validity": true Deprecate out the old vhost timer stuff that predates sul. Add a flag LWS_WITH_DEPRECATED_THINGS in cmake so users can get it back temporarily before it will be removed in a v4.2. Adapt all remaining in-tree users of it to use explicit suls. |
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|---|---|---|
| .. | ||
| async-dns | ||
| dhcpclient | ||
| ntpclient | ||
| CMakeLists.txt | ||
| README.md | ||
| system.c | ||
LWS System Helpers
Lws now has a little collection of helper utilities for common network-based functions necessary for normal device operation, eg, async DNS, ntpclient (necessary for tls validation), and DHCP client.
Conventions
If any system helper is enabled for build, lws creates an additional vhost
"system" at Context Creation time. Wsi that are created for the system
features are bound to this. In the context object, this is available as
.vhost_system.
Attaching to an existing context from other threads
To simplify the case different pieces of code want to attach to a single lws_context at runtime, from different thread contexts, lws_system has an api via an lws_system operation function pointer where the other threads can use platform-specific locking to request callbacks to their own code from the lws event loop thread context safely.
For convenience, the callback can be delayed until the system has entered or passed a specified system state, eg, LWS_SYSTATE_OPERATIONAL so the code will only get called back after the network, ntpclient and auth have been done. Additionally an opaque pointer can be passed to the callback when it is called from the lws event loop context.
Implementing the system-specific locking
lws_system_ops_t struct has a member .attach
int (*attach)(struct lws_context *context, int tsi, lws_attach_cb_t *cb,
lws_system_states_t state, void *opaque,
struct lws_attach_item **get);
This should be defined in user code as setting locking, then passing the arguments through to a non-threadsafe helper
int
__lws_system_attach(struct lws_context *context, int tsi, lws_attach_cb_t *cb,
lws_system_states_t state, void *opaque,
struct lws_attach_item **get);
that does the actual attach work. When it returns, the locking should be unlocked and the return passed back.
Attaching the callback request
User code should call the lws_system_ops_t .attach function like
lws_system_get_ops(context)->attach(...);
The callback function which will be called from the lws event loop context should look like this
void my_callback(struct lws_context *context, int tsi, void *opaque);
with the callback function name passed into the (*attach)() call above. When the callback happens, the opaque user pointer set at the (*attach)() call is passed back to it as an argument.