C++ APIs wrapping SS client
These are intended to provide an experimental protocol-independent c++
api even more abstracted than secure streams, along the lines of
"wget -Omyfile https://example.com/thing"
WIP
CTest does not directly support daemon spawn as part of the test flow,
we have to specify it as a "fixture" dependency and then hack up daemonization
in a shellscript... this last part unfortunately limits its ability to run to
unix type platforms.
On those though, if the PROXY_API cmake option is enabled, the ctest flow will
spawn the proxy and run lws-minimal-secure-strems-client against it
When ss is proxied, the handle CREATING state is deferred until the handle links up
to the proxy. So user code should only start using it when it sees CREATING. If it
tries to use it before then, we won'tget anywhere but we should make sure not to crash
on the NULL proxy link cwsi.
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.
Currently only the low 8 bits of an SS state are proxied in a total packet
length of 8 octets. Keep that format and behaviour since all the defined
states fit in 8 bits, but also allow for 32-bit states using a packet length
of 11 octets with the same command.
This lets us proxy user states (from http mapping) which start at a user
base of 1000.
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.
Before this we simply proxy the CREATING state from the proxy
version of the stream to the client version of the stream.
However this can result in disordering of onward connection
attempt request happening before the client has called back its
CREATING (*state()), meaning that any metadata set in the
state handler is missed for the onward connection.
This patch suppresses the CREATING forwarded from the proxy
and instead does its own local CREATING state callback at the
time the proxy indicates that the remote stream creation
(ie, with the requested policy streamtype) succeeded.
This then guarantees that the client has seen CREATING, and
had a chance to set metadata there, before the onward connection
request goes out. Since metadata has higher priority at the
writeable than the onward connection request it also means
any metadata set in client CREATING gets sync'd to the proxy
before the onward connection.
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.
