Break out the core ss_set_metadata action into a subfunction that
takes the lws_ss_metadata_t, and is fixed to retire heap-based
values before they go out of scope, and adapt the exported version
to call through to that.
Simplify extract_metadata() to reuse the subfunction as well, in
both well-known and custom header cases.
Teach lws how to deal with date: and retry-after:
Add quick selftest into apt-test-lws_tokenize
Expand lws_retry_sul_schedule_retry_wsi() to check for retry_after and
increase the backoff if a larger one found.
Finally, change SS h1 protocol to handle 503 + retry-after: as a
failure, and apply any increased backoff from retry-after
automatically.
This adds a per-streamtype JSON mapping table in the policy.
In addition to the previous flow, it lets you generate custom
SS state notifications for specific http response codes, eg:
"http_resp_map": [ { "530": 1530 }, { "531": 1531 } ],
It's not recommended to overload the transport-layer response
code with application layer responses. It's better to return
a 200 and then in the application protocol inside http, explain
what happened from the application perspective, usually with
JSON. But this is designed to let you handle existing systems
that do overload the transport layer response code.
SS states for user use start at LWSSSCS_USER_BASE, which is
1000.
You can do a basic test with minimal-secure-streams and --respmap
flag, this will go to httpbin.org and get a 404, and the warmcat.com
policy has the mapping for 404 -> LWSSSCS_USER_BASE (1000).
Since the mapping emits states, these are serialized and handled
like any other state in the proxy case.
The policy2c example / tool is also updated to handle the additional
mapping tables.
At the moment you can define and set per-stream metadata at the client,
which will be string-substituted and if configured in the policy, set in
related outgoing protocol specific content like h1 headers.
This patch extends the metadata concept to also check incoming protocol-
specific content like h1 headers and where it matches the binding in the
streamtype's metadata entry, make it available to the client by name, via
a new lws_ss_get_metadata() api.
Currently warmcat.com has additional headers for
server: lwsws (well-known header name)
test-custom-header: hello (custom header name)
minimal-secure-streams test is updated to try to recover these both
in direct and -client (via proxy) versions. The corresponding metadata
part of the "mintest" stream policy from warmcat.com is
{
"srv": "server:"
}, {
"test": "test-custom-header:"
},
If built direct, or at the proxy, the stream has access to the static
policy metadata definitions and can store the rx metadata in the stream
metadata allocation, with heap-allocated a value. For client side that
talks to a proxy, only the proxy knows the policy, and it returns rx
metadata inside the serialized link to the client, which stores it on
the heap attached to the stream.
In addition an optimization for mapping static policy metadata definitions
to individual stream handle metadata is changed to match by name.
Formalize the LWSSSSRET_ enums into a type "lws_ss_state_return_t"
returned by the rx, tx and state callbacks, and some private helpers
lws_ss_backoff() and lws_ss_event_helper().
Remove LWSSSSRET_SS_HANDLE_DESTROYED concept... the two helpers that could
have destroyed the ss and returned that, now return LWSSSSRET_DESTROY_ME
to the caller to perform or pass up to their caller instead.
Handle helper returns in all the ss protocols and update the rx / tx
calls to have their returns from rx / tx / event helper and ss backoff
all handled by unified code.
Change the default to not process multipart mime at SS layer.
If it's desired, then set "http_multipart_ss_in" true in the policy on the streamtype.
To test, use lws-minimal-secure-streams-avs, which uses SS processing as it is.
To check it without the processing, change #if 1 to #if 0 around the policy for
"http_multipart_ss_in" in both places in avs.c, and also enable the hexdump in ss_avs_metadata_rx()
also in avs.c, and observe the multipart framing is passed through unchanged.
Add initial support for defining servers using Secure Streams
policy and api semantics.
Serving h1, h2 and ws should be functional, the new minimal
example shows a combined http + SS server with an incrementing
ws message shown in the browser over tls, in around 200 lines
of user code.
NOP out anything to do with plugins, they're not currently used.
Update the docs correspondingly.
Presently a vh is allocated per trust store at policy parsing-time, this
is no problem on a linux-class device or if you decide you need a dynamic
policy for functionality reasons.
However if you're in a constrained enough situation that the static policy
makes sense, in the case your trust stores do not have 100% duty cycle, ie,
are anyway always in use, the currently-unused vhosts and their x.509 stack
are sitting there taking up heap for no immediate benefit.
This patch modifies behaviour in ..._STATIC_POLICY_ONLY so that vhosts and
associated x.509 tls contexts are not instantiated until a secure stream using
them is created; they are refcounted, and when the last logical secure
stream using a vhost is destroyed, the vhost and its tls context is also
destroyed.
If another ss connection is created that wants to use the trust store, the
vhost and x.509 context is regenerated again as needed.
Currently the refcounting is by ss, it's also possible to move the refcounting
to be by connection. The choice is between the delay to generate the vh
being visisble at logical ss creation-time, or at connection-time. It's anyway
not preferable to have ss instantiated and taking up space with no associated
connection or connection attempt underway.
NB you will need to reprocess any static policies after this patch so they
conform to the trust_store changes.
Currently we always reserve a fakewsi per pt so events that don't have a related actual
wsi, like vhost-protocol-init or vhost cert init via protocol callback can make callbacks
that look reasonable to user protocol handler code expecting a valid wsi every time.
This patch splits out stuff that user callbacks often unconditionally expect to be in
a wsi, like context pointer, vhost pointer etc into a substructure, which is composed
into struct lws at the top of it. Internal references (struct lws is opaque, so there
are only internal references) are all updated to go via the substructre, the compiler
should make that a NOP.
Helpers are added when fakewsi is used and referenced.
If not PLAT_FREERTOS, we continue to provide a full fakewsi in the pt as before,
although the helpers improve consistency by zeroing down the substructure. There is
a huge amount of user code out there over the last 10 years that did not always have
the minimal examples to follow, some of it does some unexpected things.
If it is PLAT_FREERTOS, that is a newer thing in lws and users have the benefit of
being able to follow the minimal examples' approach. For PLAT_FREERTOS we don't
reserve the fakewsi in the pt any more, saving around 800 bytes. The helpers then
create a struct lws_a (the substructure) on the stack, zero it down (but it is only
like 4 pointers) and prepare it with whatever we know like the context.
Then we cast it to a struct lws * and use it in the user protocol handler call.
In this case, the remainder of the struct lws is undefined. However the amount of
old protocol handlers that might touch things outside of the substructure in
PLAT_FREERTOS is very limited compared to legacy lws user code and the saving is
significant on constrained devices.
User handlers should not be touching everything in a wsi every time anyway, there
are several cases where there is no valid wsi to do the call with. Dereference of
things outside the substructure should only happen when the callback reason shows
there is a valid wsi bound to the activity (as in all the minimal examples).
Callbacks can ask the caller to, eg, destroy the ss handle now. But some
callback returns are handled and produced inside other helper apis, eg
lws_ss_backoff() may have to had fulfilled the callback request to destroy
the ss... therefore it has to signal to its caller, and its callers have
to check and exit their flow accordingly.
Allow usage of ${metadata} string substitution in more policy elements
for MQTT:
- associated subscription topic in policy
- associated publish topic in policy
- associated will topic in policy
- associated will message in policy
Tested against lws-minimal-mqtt-client-multi / mosquitto
It's not safe to destroy objects inside a callback from a parent that
still has references to the object.
Formalize what the user code can indicate by its return code from the
callback functions and provide the implementations at the parents.
- LWSSSSRET_OK: no action, OK
- LWSSSSRET_DISCONNECT_ME: disconnect the underlying connection
- LWSSSSRET_DESTROY_ME: destroy the ss object
- LWSSSSRET_TX_DONT_SEND: for tx, give up the tx opportunity since nothing to send
Some streamtypes do not pass or receive payload meaningfully. Allow them
to just leave their related cb NULL. Ditto for state, although I'm not sure
how useful such a streamtype can be.
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.
When most of ss-h2 was combined into ss-h1 during development, the h2 difference
about needing HTTP_FINAL to signal h2 FIN flag was accidentally dropped. In
many cases the peer can infer it, from, eg, content-length reached. But we need
to replace explicitly doing it to cover all cases.
You can disconnect the stream by returning -1 from tx(). You can
give up your chance to send anything by returning 1 from tx().
Returning 0 sends `*len` amount of the provided buffer.
Returning <0 from rx() also disconnects the stream.
