src/mux_h2.c

/*
 * HTTP/2 mux-demux for connections
 *
 * Copyright 2017 Willy Tarreau <w@1wt.eu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 */

#include <common/cfgparse.h>
#include <common/config.h>
#include <proto/connection.h>
#include <proto/stream.h>


/* a few settings from the global section */
static int h2_settings_header_table_size      =  4096; /* initial value */
static int h2_settings_initial_window_size    = 65535; /* initial value */
static int h2_settings_max_concurrent_streams =   100;


/*****************************************************************/
/* functions below are dedicated to the mux setup and management */
/*****************************************************************/

/* Initialize the mux once it's attached. For outgoing connections, the context
 * is already initialized before installing the mux, so we detect incoming
 * connections from the fact that the context is still NULL. Returns < 0 on
 * error.
 */
static int h2_init(struct connection *conn)
{
	if (conn->mux_ctx) {
		/* we don't support outgoing connections for now */
		return -1;
	}

	/* not implemented yet */
	return -1;
}

/* release function for a connection. This one should be called to free all
 * resources allocated to the mux.
 */
static void h2_release(struct connection *conn)
{
}


/*********************************************************/
/* functions below are I/O callbacks from the connection */
/*********************************************************/

/* callback called on recv event by the connection handler */
static void h2_recv(struct connection *conn)
{
}

/* callback called on send event by the connection handler */
static void h2_send(struct connection *conn)
{
}

/* callback called on any event by the connection handler.
 * It applies changes and returns zero, or < 0 if it wants immediate
 * destruction of the connection (which normally doesn not happen in h2).
 */
static int h2_wake(struct connection *conn)
{
	return 0;
}

/*******************************************/
/* functions below are used by the streams */
/*******************************************/

/*
 * Attach a new stream to a connection
 * (Used for outgoing connections)
 */
static struct conn_stream *h2_attach(struct connection *conn)
{
	return NULL;
}

/* callback used to update the mux's polling flags after changing a cs' status.
 * The caller (cs_update_mux_polling) will take care of propagating any changes
 * to the transport layer.
 */
static void h2_update_poll(struct conn_stream *cs)
{
}

/*
 * Detach the stream from the connection and possibly release the connection.
 */
static void h2_detach(struct conn_stream *cs)
{
}

static void h2_shutr(struct conn_stream *cs, enum cs_shr_mode mode)
{
}

static void h2_shutw(struct conn_stream *cs, enum cs_shw_mode mode)
{
}

/*
 * Called from the upper layer, to get more data
 */
static int h2_rcv_buf(struct conn_stream *cs, struct buffer *buf, int count)
{
	/* FIXME: not handled for now */
	cs->flags |= CS_FL_ERROR;
	return 0;
}

/* Called from the upper layer, to send data */
static int h2_snd_buf(struct conn_stream *cs, struct buffer *buf, int flags)
{
	/* FIXME: not handled for now */
	cs->flags |= CS_FL_ERROR;
	return 0;
}


/*******************************************************/
/* functions below are dedicated to the config parsers */
/*******************************************************/

/* config parser for global "tune.h2.header-table-size" */
static int h2_parse_header_table_size(char **args, int section_type, struct proxy *curpx,
                                      struct proxy *defpx, const char *file, int line,
                                      char **err)
{
	if (too_many_args(1, args, err, NULL))
		return -1;

	h2_settings_header_table_size = atoi(args[1]);
	if (h2_settings_header_table_size < 4096 || h2_settings_header_table_size > 65536) {
		memprintf(err, "'%s' expects a numeric value between 4096 and 65536.", args[0]);
		return -1;
	}
	return 0;
}

/* config parser for global "tune.h2.initial-window-size" */
static int h2_parse_initial_window_size(char **args, int section_type, struct proxy *curpx,
                                        struct proxy *defpx, const char *file, int line,
                                        char **err)
{
	if (too_many_args(1, args, err, NULL))
		return -1;

	h2_settings_initial_window_size = atoi(args[1]);
	if (h2_settings_initial_window_size < 0) {
		memprintf(err, "'%s' expects a positive numeric value.", args[0]);
		return -1;
	}
	return 0;
}

/* config parser for global "tune.h2.max-concurrent-streams" */
static int h2_parse_max_concurrent_streams(char **args, int section_type, struct proxy *curpx,
                                           struct proxy *defpx, const char *file, int line,
                                           char **err)
{
	if (too_many_args(1, args, err, NULL))
		return -1;

	h2_settings_max_concurrent_streams = atoi(args[1]);
	if (h2_settings_max_concurrent_streams < 0) {
		memprintf(err, "'%s' expects a positive numeric value.", args[0]);
		return -1;
	}
	return 0;
}


/****************************************/
/* MUX initialization and instanciation */
/***************************************/

/* The mux operations */
const struct mux_ops h2_ops = {
	.init = h2_init,
	.recv = h2_recv,
	.send = h2_send,
	.wake = h2_wake,
	.update_poll = h2_update_poll,
	.rcv_buf = h2_rcv_buf,
	.snd_buf = h2_snd_buf,
	.attach = h2_attach,
	.detach = h2_detach,
	.shutr = h2_shutr,
	.shutw = h2_shutw,
	.release = h2_release,
	.name = "H2",
};

/* ALPN selection : this mux registers ALPN tolen "h2" */
static struct alpn_mux_list alpn_mux_h2 =
	{ .token = IST("h2"), .mode = ALPN_MODE_HTTP, .mux = &h2_ops };

/* config keyword parsers */
static struct cfg_kw_list cfg_kws = {ILH, {
	{ CFG_GLOBAL, "tune.h2.header-table-size",      h2_parse_header_table_size      },
	{ CFG_GLOBAL, "tune.h2.initial-window-size",    h2_parse_initial_window_size    },
	{ CFG_GLOBAL, "tune.h2.max-concurrent-streams", h2_parse_max_concurrent_streams },
	{ 0, NULL, NULL }
}};

__attribute__((constructor))
static void __h2_init(void)
{
	alpn_register_mux(&alpn_mux_h2);
	cfg_register_keywords(&cfg_kws);
}