This method is used to retrieve the first known good conn_stream from
the mux. It will be used to find the other end of a connection when
dealing with the proxy protocol for example.
Commit d4dd22d ("MINOR: h2: Let user of h2_recv() and h2_send() know xfer
has been done") changed the API without documenting the expected returned
values which appear to come out of nowhere in the code :-( Please don't
do that anymore! The description was recovered from the commit message.
We wake up all the streams waiting to send data when we have space available
in the mux buffer. Doing so means we probably wake way too many streams,
because after a few the buffer will probably be full instead. So keep a
list of all the streams that are about to send data, and if we detect that
the buffer is full, unschedule the tasks and put the streams back to the
send_list.
Avoid using conn_xprt_want_send/recv, and totally nuke cs_want_send/recv,
from the upper layers. The polling is now directly handled by the connection
layer, it is activated on subscribe(), and unactivated once we got the event
and we woke the related task.
In h2_recv(), return 1 if we have data available, or if h2_recv_allowed()
failed, to be sure h2_process() is called.
Also don't subscribe if our buffer is full.
When we're closing a stream, is there's no stream left and a goaway was sent,
close the connection, there's no reason to keep it open.
[wt: it's likely that this is needed in 1.8 as well, though it's unclear
how to trigger this issue, some tests are needed]
We will need to know if a mux was created for a front or a back
connection and once it's established it's much harder, so let's
introduce H2_CF_IS_BACK for this.
For backend connections we'll have to initialize streams but not allocate
conn_streams since they'll already be there. Thus this patch splits the
h2c_stream_new() function into one dedicated to allocation of a new stream
and another one supposed to attach this stream to an existing frontend
connection.
Till now in order to figure the timeouts, we used to retrieve the proxy
from the session's owner, but the new API provides it so it's better to
simply take it from the caller at init time. We take this opportunity to
store the pointer to the proxy into the h2 connection so that we can
reuse it later when needed.
The init function was split into the mux init and the front init, but it
appears that most of the code will be common between the two sides when
implementing the backend init. Thus let's simply make this a unique
h2_init() function.
h2_snd_buf() must not accept to send data if the preface was not yet
received nor sent. At the moment it doesn't happen but it can with
server-side H2.
At a few places we check these states to detect if a stream has valid
data/errcode or is one of the two dummy streams (idle or closed). It
will become problematic for outgoing streams as it will not be possible
to report errors for example since the stream will switch from IDLE
state only after sending a HEADERS frame.
There is a safer solution consisting in checking the stream ID, which
may only be zero in the dummy streams. This patch changes the test to
only rely on the stream ID.
If we can't send data for a stream because of its flow control, make sure
not to put it in the send_list, until the flow control lets it send again.
This is specific to 1.9, and should not be backported.
When subscribing, we don't need to provide a list element, only the h2 mux
needs it. So instead, Add a list element to struct h2s, and use it when a
list is needed.
This forces us to use the unsubscribe method, since we can't just unsubscribe
by using LIST_DEL anymore.
This patch is larger than it should be because it includes some renaming.
As we don't know how subscriptions are handled, we can't just assume we can
use LIST_DEL() to unsubscribe, so introduce a new method to mux and connections
to do so.
Commit 8ae735da0 ("MEDIUM: mux_h2: Revamp the send path when blocking.")
added a tasklet allocation in h2_stream_new(), however the error exit path
fails to reset h2s in case the tasklet cannot be allocated, resulting in
the h2s pointer to be returned as valid to the caller. Let's readjust the
exit path to always return NULL on error and to always log as well (since
there is no reason for not logging on such important errors).
No backport is needed, this is strictly 1.9-dev.
Since commit 7505f94f9 ("MEDIUM: h2: Don't use a wake() method anymore."),
the H2 mux's init() calls h2_process(). But this last one may detect an
early error and call h2_release(), destroying the connection, and return
-1. At this point we're screwed because the caller will still dereference
the connection for various things ranging from the configuration of the
proxy protocol header to the retries. We could simply return -1 here upon
failure but that's not enough since the stream layer really needs to keep
its connection structure allocated (to clean it up in session_kill_embryonic
or for example because it holds the destination address to reconnect to
when the connection goes to the backend). Thus the correct solution here is
to only schedule a wakeup of the I/O callback so that the init succeeds,
and that the connection is only handled later.
No backport is needed, this is 1.9-specific.
While it was possible to consider the status before parsing response
headers, it's wrong to do it for request headers and could lead to
random behaviours due to this status matching other fields instead.
Additionnally there is little to no value in doing this for each and
every new header field. It's much better to reset the content-length
at once in the callerwhen seeing such statuses (which currently is only
the H2 mux).
No backport is needed, this is purely 1.9.
The h2 parser has this specificity that if it cannot send the headers
frame resulting from the headers it just parsed, it needs to drop it
and parse it again later. Since commit 8852850 ("MEDIUM: h1: let the
caller pass the initial parser's state"), when this happens the parser
remains in the data state and the headers are not parsed again next
time, resulting in a parse error. Let's reset the parser on exit there.
No backport is needed.
If we're detaching the conn_stream, and it was subscribed to be waken up
when more data was available to receive, unsubscribe it.
No backport is needed.
Empty both send_list and fctl_list when destroying the h2 context, so that
if we're freeing the stream after, it doesn't try to remove itself from the
now-deleted list.
No backport is needed.
Till now it was very difficult for a mux to know what proxy it was
working for. Let's pass the proxy when the mux is instanciated at
init() time. It's not yet used but the H1 mux will definitely need
it, just like the H2 mux when dealing with backend connections.
The h1 parser used to systematically turn header field names to lower
case because it was designed for H2. Let's add a flag which is off by
default to condition this behaviour so that when using it from an H1
parser it will not affect the message.
The HTTP status is not relevant to the H1 message but to the H2 stream
itself. It used to be placed there by pure convenience but better move
it before it's too hard to remove.
This state was only a delimiter between headers and body but it now
causes more harm than good because it requires someone to change it.
Since the H1 parser knows if we're in DATA or CHUNK_SIZE, simply let
it set the right next state so that h1m->state constantly matches
what is expected afterwards.
This will allow the parser to fill some extra fields like the method or
status without having to store them permanently in the HTTP message. At
this point however the parser cannot restart from an interrupted read.
There's no reason to have the two sides in H1 format since we only use
one at a time (the response at the moment). While completely removing
the request declaration, let's rename the response to "h1m" to clarify
that it's the unique h1 message there.
This is the *parsing* state of an HTTP/1 message. Currently the h1_state
is composite as it's made both of parsing and control (100SENT, BODY,
DONE, TUNNEL, ENDING etc). The purpose here is to have a purely H1 state
that can be used by H1 parsers. For now it's equivalent to h1_state.
Instead of waiting for the connection layer to let us know we can read,
attempt to receive as soon as process_stream() is called, and subscribe
to receive events if we can't receive yet.
Now, except for idle connections, the recv(), send() and wake() methods are
no more, all the lower layers do is waking tasklet for anybody waiting
for I/O events.
Change fctl_list and send_list to be lists of struct wait_list, and nuke
send_wait_list, as it's now redundant.
Make the code responsible for shutr/shutw subscribe to those lists.
Instead of having our wake() method called each time a fd event happens,
just subscribe to recv/send events, and get our tasklet called when that
happens. If any recv/send was possible, the equivalent of what h2_wake_cb()
will be done.
Let the connection layer know we're always interested in getting more data,
so that we get scheduled as soon as data is available, instead of relying
on the wake() method.
Make h2_recv() and h2_send() return 1 if data has been sent/received, or 0
if it did not. That way the caller will be able to know if more work may
have to be done.
Remove the recv() method from mux and conn_stream.
The goal is to always receive from the upper layers, instead of waiting
for the connection later. For now, recv() is still called from the wake()
method, but that should change soon.
For struct connection, struct conn_stream, and for the h2 mux, add 2 new
lists, one that handles waiters for recv, and one that handles waiters for
recv and send. That way we can ask to subscribe for either recv or send.
Christopher noticed that the CS_FL_EOS to CS_FL_REOS conversion was
incomplete : when the connectionis closed, we mark the streams with EOS
instead of REOS, causing the loss of any possibly pending data. At the
moment it's not an issue since H2 is used only with a client, but with
servers it could be a real problem if servers close the connection right
after sending their response.
This patch should be backported to 1.8.
The h2 mux currently lacks some basic transparency. Some errors cause the
connection to be aborted but they couldn't be reported. With this patch,
almost all situations where an error will cause a stream or connection to
be aborted without the ability for an existing stream to report it will be
reported in the logs. This at least provides a solution to monitor the
activity and abnormal traffic.
While parsing a headers frame, if the frame is wrapped in the buffer
and needs to be unwrapped, it will be duplicated before being processed.
But if it contains certain combinations of invalid flags, the parser
returns without releasing the temporary buffer leading to a memory
leak.
This fix needs to be backported to 1.8.
The handshake processing time used to be stored per stream, which was
valid when there was exactly one stream per session. With H2 and
multiplexing it's not the case anymore and the reported handshake times
are wrong in the logs as it's computed between the TCP accept() and the
stream creation. Let's first move the handshake where it belongs, which
is the session.
However, this is not enough because we don't want to report an excessive
idle time either for H2 (since many requests use the connection).
So the solution used here is to have the stream retrieve sess->tv_accept
and the handshake duration when the stream is created, and let the mux
immediately reset them. This way, the handshake time becomes zero for the
second and subsequent requests in H2 (which was already the case in H1),
and the idle time exactly counts how long the connection remained unused
while it could be used, so in H1 it runs from the end of the previous
response and in H2 it runs from the end of the previous request since the
channel is already available.
This patch will need to be backported to 1.8.
