text: /*
   * include/proto/stream_interface.h
   * This file contains stream_interface function prototypes
   *
   * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation, version 2.1
   * exclusively.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #ifndef _PROTO_STREAM_INTERFACE_H
  #define _PROTO_STREAM_INTERFACE_H
  
  #include <stdlib.h>
  
  #include <common/config.h>
  #include <types/server.h>
  #include <types/stream.h>
  #include <types/stream_interface.h>
  #include <proto/applet.h>
  #include <proto/channel.h>
  #include <proto/connection.h>
  
  
  extern struct si_ops si_embedded_ops;
  extern struct si_ops si_conn_ops;
  extern struct si_ops si_applet_ops;
  extern struct data_cb si_conn_cb;
  
  /* main event functions used to move data between sockets and buffers */
  int si_check_timeouts(struct stream_interface *si);
  void si_report_error(struct stream_interface *si);
  void si_retnclose(struct stream_interface *si, const struct buffer *msg);
  int conn_si_send_proxy(struct connection *conn, unsigned int flag);
  struct appctx *si_register_handler(struct stream_interface *si, struct applet *app);
  void si_applet_wake_cb(struct stream_interface *si);
  void si_update(struct stream_interface *si);
  int si_cs_recv(struct conn_stream *cs);
  struct task *si_cs_io_cb(struct task *t, void *ctx, unsigned short state);
  void si_update_both(struct stream_interface *si_f, struct stream_interface *si_b);
  
  /* returns the channel which receives data from this stream interface (input channel) */
  static inline struct channel *si_ic(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_ISBACK)
  		return &LIST_ELEM(si, struct stream *, si[1])->res;
  	else
  		return &LIST_ELEM(si, struct stream *, si[0])->req;
  }
  
  /* returns the channel which feeds data to this stream interface (output channel) */
  static inline struct channel *si_oc(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_ISBACK)
  		return &LIST_ELEM(si, struct stream *, si[1])->req;
  	else
  		return &LIST_ELEM(si, struct stream *, si[0])->res;
  }
  
  /* returns the buffer which receives data from this stream interface (input channel's buffer) */
  static inline struct buffer *si_ib(struct stream_interface *si)
  {
  	return &si_ic(si)->buf;
  }
  
  /* returns the buffer which feeds data to this stream interface (output channel's buffer) */
  static inline struct buffer *si_ob(struct stream_interface *si)
  {
  	return &si_oc(si)->buf;
  }
  
  /* returns the stream associated to a stream interface */
  static inline struct stream *si_strm(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_ISBACK)
  		return LIST_ELEM(si, struct stream *, si[1]);
  	else
  		return LIST_ELEM(si, struct stream *, si[0]);
  }
  
  /* returns the task associated to this stream interface */
  static inline struct task *si_task(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_ISBACK)
  		return LIST_ELEM(si, struct stream *, si[1])->task;
  	else
  		return LIST_ELEM(si, struct stream *, si[0])->task;
  }
  
  /* returns the stream interface on the other side. Used during forwarding. */
  static inline struct stream_interface *si_opposite(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_ISBACK)
  		return &LIST_ELEM(si, struct stream *, si[1])->si[0];
  	else
  		return &LIST_ELEM(si, struct stream *, si[0])->si[1];
  }
  
  /* initializes a stream interface in the SI_ST_INI state. It's detached from
   * any endpoint and only keeps its side which is expected to have already been
   * set.
   */
  static inline int si_reset(struct stream_interface *si)
  {
  	si->err_type       = SI_ET_NONE;
  	si->conn_retries   = 0;  /* used for logging too */
  	si->exp            = TICK_ETERNITY;
  	si->flags         &= SI_FL_ISBACK;
  	si->end            = NULL;
  	si->state          = si->prev_state = SI_ST_INI;
  	si->ops            = &si_embedded_ops;
  	si->wait_event.task = tasklet_new();
  	if (!si->wait_event.task)
  		return -1;
  	si->wait_event.task->process    = si_cs_io_cb;
  	si->wait_event.task->context = si;
  	si->wait_event.events = 0;
  	return 0;
  }
  
  /* sets the current and previous state of a stream interface to <state>. This
   * is mainly used to create one in the established state on incoming
   * conncetions.
   */
  static inline void si_set_state(struct stream_interface *si, int state)
  {
  	si->state = si->prev_state = state;
  }
  
  /* only detaches the endpoint from the SI, which means that it's set to
   * NULL and that ->ops is mapped to si_embedded_ops. The previous endpoint
   * is returned.
   */
  static inline enum obj_type *si_detach_endpoint(struct stream_interface *si)
  {
  	enum obj_type *prev = si->end;
  
  	si->end = NULL;
  	si->ops = &si_embedded_ops;
  	return prev;
  }
  
  /* Release the endpoint if it's a connection or an applet, then nullify it.
   * Note: released connections are closed then freed.
   */
  static inline void si_release_endpoint(struct stream_interface *si)
  {
  	struct connection *conn;
  	struct conn_stream *cs;
  	struct appctx *appctx;
  
  	if (!si->end)
  		return;
  
  	if ((cs = objt_cs(si->end))) {
  		if (si->wait_event.events != 0)
  			cs->conn->mux->unsubscribe(cs, si->wait_event.events,
  			    &si->wait_event);
  		cs_destroy(cs);
  	}
  	else if ((appctx = objt_appctx(si->end))) {
  		if (appctx->applet->release && si->state < SI_ST_DIS)
  			appctx->applet->release(appctx);
  		appctx_free(appctx); /* we share the connection pool */
  	} else if ((conn = objt_conn(si->end))) {
  		conn_stop_tracking(conn);
  		conn_full_close(conn);
  		conn_free(conn);
  	}
  	si_detach_endpoint(si);
  }
  
  /* Attach conn_stream <cs> to the stream interface <si>. The stream interface
   * is configured to work with a connection and the connection it configured
   * with a stream interface data layer.
   */
  static inline void si_attach_cs(struct stream_interface *si, struct conn_stream *cs)
  {
  	si->ops = &si_conn_ops;
  	si->end = &cs->obj_type;
  	cs_attach(cs, si, &si_conn_cb);
  }
  
  /* Returns true if a connection is attached to the stream interface <si> and
   * if this connection is ready.
   */
  static inline int si_conn_ready(struct stream_interface *si)
  {
  	struct connection *conn = cs_conn(objt_cs(si->end));
  
  	return conn && conn_ctrl_ready(conn) && conn_xprt_ready(conn);
  }
  
  /* Attach appctx <appctx> to the stream interface <si>. The stream interface
   * is configured to work with an applet context.
   */
  static inline void si_attach_appctx(struct stream_interface *si, struct appctx *appctx)
  {
  	si->ops = &si_applet_ops;
  	si->end = &appctx->obj_type;
  	appctx->owner = si;
  }
  
  /* returns a pointer to the appctx being run in the SI, which must be valid */
  static inline struct appctx *si_appctx(struct stream_interface *si)
  {
  	return __objt_appctx(si->end);
  }
  
  /* call the applet's release function if any. Needs to be called upon close() */
  static inline void si_applet_release(struct stream_interface *si)
  {
  	struct appctx *appctx;
  
  	appctx = objt_appctx(si->end);
  	if (appctx && appctx->applet->release && si->state < SI_ST_DIS)
  		appctx->applet->release(appctx);
  }
  
  /* Returns non-zero if the stream interface's Rx path is blocked */
  static inline int si_rx_blocked(const struct stream_interface *si)
  {
  	return !!(si->flags & SI_FL_RXBLK_ANY);
  }
  
  /* Returns non-zero if the stream interface's endpoint is ready to receive */
  static inline int si_rx_endp_ready(const struct stream_interface *si)
  {
  	return !(si->flags & SI_FL_RX_WAIT_EP);
  }
  
  /* The stream interface announces it is ready to try to deliver more data to the input buffer */
  static inline void si_rx_endp_more(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_RX_WAIT_EP;
  }
  
  /* The stream interface announces it doesn't have more data for the input buffer */
  static inline void si_rx_endp_done(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RX_WAIT_EP;
  }
  
  /* Tell a stream interface the input channel is OK with it sending it some data */
  static inline void si_rx_chan_rdy(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_RXBLK_CHAN;
  }
  
  /* Tell a stream interface the input channel is not OK with it sending it some data */
  static inline void si_rx_chan_blk(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RXBLK_CHAN;
  }
  
  /* Tell a stream interface the other side is connected */
  static inline void si_rx_conn_rdy(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_RXBLK_CONN;
  }
  
  /* Tell a stream interface it must wait for the other side to connect */
  static inline void si_rx_conn_blk(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RXBLK_CONN;
  }
  
  /* The stream interface just got the input buffer it was waiting for */
  static inline void si_rx_buff_rdy(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_RXBLK_BUFF;
  }
  
  /* The stream interface failed to get an input buffer and is waiting for it.
   * Since it indicates a willingness to deliver data to the buffer that will
   * have to be retried, we automatically clear RXBLK_ENDP to be called again
   * as soon as RXBLK_BUFF is cleared.
   */
  static inline void si_rx_buff_blk(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RXBLK_BUFF;
  }
  
  /* Tell a stream interface some room was made in the input buffer */
  static inline void si_rx_room_rdy(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_RXBLK_ROOM;
  }
  
  /* The stream interface announces it failed to put data into the input buffer
   * by lack of room. Since it indicates a willingness to deliver data to the
   * buffer that will have to be retried, we automatically clear RXBLK_ENDP to
   * be called again as soon as RXBLK_ROOM is cleared.
   */
  static inline void si_rx_room_blk(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RXBLK_ROOM;
  }
  
  /* The stream interface announces it will never put new data into the input
   * buffer and that it's not waiting for its endpoint to deliver anything else.
   * This function obviously doesn't have a _rdy equivalent.
   */
  static inline void si_rx_shut_blk(struct stream_interface *si)
  {
  	si->flags |=  SI_FL_RXBLK_SHUT;
  }
  
  /* Returns non-zero if the stream interface's Rx path is blocked */
  static inline int si_tx_blocked(const struct stream_interface *si)
  {
  	return !!(si->flags & SI_FL_WAIT_DATA);
  }
  
  /* Returns non-zero if the stream interface's endpoint is ready to transmit */
  static inline int si_tx_endp_ready(const struct stream_interface *si)
  {
  	return (si->flags & SI_FL_WANT_GET);
  }
  
  /* Report that a stream interface wants to get some data from the output buffer */
  static inline void si_want_get(struct stream_interface *si)
  {
  	si->flags |= SI_FL_WANT_GET;
  }
  
  /* Report that a stream interface failed to get some data from the output buffer */
  static inline void si_cant_get(struct stream_interface *si)
  {
  	si->flags |= SI_FL_WANT_GET | SI_FL_WAIT_DATA;
  }
  
  /* Report that a stream interface doesn't want to get data from the output buffer */
  static inline void si_stop_get(struct stream_interface *si)
  {
  	si->flags &= ~SI_FL_WANT_GET;
  }
  
  /* Report that a stream interface won't get any more data from the output buffer */
  static inline void si_done_get(struct stream_interface *si)
  {
  	si->flags &= ~(SI_FL_WANT_GET | SI_FL_WAIT_DATA);
  }
  
  /* Try to allocate a new conn_stream and assign it to the interface. If
   * an endpoint was previously allocated, it is released first. The newly
   * allocated conn_stream is initialized, assigned to the stream interface,
   * and returned.
   */
  static inline struct conn_stream *si_alloc_cs(struct stream_interface *si, struct connection *conn)
  {
  	struct conn_stream *cs;
  
  	si_release_endpoint(si);
  
  	cs = cs_new(conn);
  	if (cs)
  		si_attach_cs(si, cs);
  
  	return cs;
  }
  
  /* Try to allocate a buffer for the stream-int's input channel. It relies on
   * channel_alloc_buffer() for this so it abides by its rules. It returns 0 on
   * failure, non-zero otherwise. If no buffer is available, the requester,
   * represented by the <wait> pointer, will be added in the list of objects
   * waiting for an available buffer, and SI_FL_RXBLK_BUFF will be set on the
   * stream-int and SI_FL_RX_WAIT_EP cleared. The requester will be responsible
   * for calling this function to try again once woken up.
   */
  static inline int si_alloc_ibuf(struct stream_interface *si, struct buffer_wait *wait)
  {
  	int ret;
  
  	ret = channel_alloc_buffer(si_ic(si), wait);
  	if (!ret)
  		si_rx_buff_blk(si);
  	return ret;
  }
  
  /* Release the interface's existing endpoint (connection or appctx) and
   * allocate then initialize a new appctx which is assigned to the interface
   * and returned. NULL may be returned upon memory shortage. Applet <applet>
   * is assigned to the appctx, but it may be NULL.
   */
  static inline struct appctx *si_alloc_appctx(struct stream_interface *si, struct applet *applet)
  {
  	struct appctx *appctx;
  
  	si_release_endpoint(si);
  	appctx = appctx_new(applet, tid_bit);
  	if (appctx) {
  		si_attach_appctx(si, appctx);
  		appctx->t->nice = si_strm(si)->task->nice;
  	}
  
  	return appctx;
  }
  
  /* Sends a shutr to the connection using the data layer */
  static inline void si_shutr(struct stream_interface *si)
  {
  	si->ops->shutr(si);
  }
  
  /* Sends a shutw to the connection using the data layer */
  static inline void si_shutw(struct stream_interface *si)
  {
  	si->ops->shutw(si);
  }
  
  /* This is to be used after making some room available in a channel. It will
   * return without doing anything if the stream interface's RX path is blocked.
   * It will automatically mark the stream interface as busy processing the end
   * point in order to avoid useless repeated wakeups.
   * It will then call ->chk_rcv() to enable receipt of new data.
   */
  static inline void si_chk_rcv(struct stream_interface *si)
  {
  	if (si->flags & SI_FL_RXBLK_CONN && (si_opposite(si)->state >= SI_ST_EST))
  		si_rx_conn_rdy(si);
  
  	if (si_rx_blocked(si) || !si_rx_endp_ready(si))
  		return;
  
  	if (si->state != SI_ST_EST)
  		return;
  
  	si->flags |= SI_FL_RX_WAIT_EP;
  	si->ops->chk_rcv(si);
  }
  
  /* This tries to perform a synchronous receive on the stream interface to
   * try to collect last arrived data. In practice it's only implemented on
   * conn_streams. Returns 0 if nothing was done, non-zero if new data or a
   * shutdown were collected. This may result on some delayed receive calls
   * to be programmed and performed later, though it doesn't provide any
   * such guarantee.
   */
  static inline int si_sync_recv(struct stream_interface *si)
  {
  	struct conn_stream *cs;
  
  	if (si->state != SI_ST_EST)
  		return 0;
  
  	cs = objt_cs(si->end);
  	if (!cs)
  		return 0; // only conn_streams are supported
  
  	if (si->wait_event.events & SUB_RETRY_RECV)
  		return 0; // already subscribed
  
  	if (!si_rx_endp_ready(si) || si_rx_blocked(si))
  		return 0; // already failed
  
  	return si_cs_recv(cs);
  }
  
  /* Calls chk_snd on the connection using the data layer */
  static inline void si_chk_snd(struct stream_interface *si)
  {
  	si->ops->chk_snd(si);
  }
  
  /* Calls chk_snd on the connection using the ctrl layer */
  static inline int si_connect(struct stream_interface *si, struct connection *conn)
  {
  	int ret = SF_ERR_NONE;
  
  	if (unlikely(!conn || !conn->ctrl || !conn->ctrl->connect))
  		return SF_ERR_INTERNAL;
  
  	if (!conn_ctrl_ready(conn) || !conn_xprt_ready(conn)) {
  		ret = conn->ctrl->connect(conn, !channel_is_empty(si_oc(si)), 0);
  		if (ret != SF_ERR_NONE)
  			return ret;
  
  		/* we're in the process of establishing a connection */
  		si->state = SI_ST_CON;
  	}
  	else {
  		/* reuse the existing connection */
  
  		/* the connection is established */
  		si->state = SI_ST_EST;
  	}
  
  	/* needs src ip/port for logging */
  	if (si->flags & SI_FL_SRC_ADDR)
  		conn_get_from_addr(conn);
  
  	return ret;
  }
  
  /* Returns info about the conn_stream <cs>, if not NULL. It call the mux layer's
   * get_cs_info() function, if it exists. On success, it returns a cs_info
   * structure. Otherwise, on error, if the mux does not implement get_cs_info()
   * or if conn_stream is NULL, NULL is returned.
   */
  static inline const struct cs_info *si_get_cs_info(struct conn_stream *cs)
  {
  	if (cs && cs->conn->mux->get_cs_info)
  		return cs->conn->mux->get_cs_info(cs);
  	return NULL;
  }
  
  /* for debugging, reports the stream interface state name */
  static inline const char *si_state_str(int state)
  {
  	switch (state) {
  	case SI_ST_INI: return "INI";
  	case SI_ST_REQ: return "REQ";
  	case SI_ST_QUE: return "QUE";
  	case SI_ST_TAR: return "TAR";
  	case SI_ST_ASS: return "ASS";
  	case SI_ST_CON: return "CON";
  	case SI_ST_CER: return "CER";
  	case SI_ST_EST: return "EST";
  	case SI_ST_DIS: return "DIS";
  	case SI_ST_CLO: return "CLO";
  	default:        return "???";
  	}
  }
  
  #endif /* _PROTO_STREAM_INTERFACE_H */
  
  /*
   * Local variables:
   *  c-indent-level: 8
   *  c-basic-offset: 8
   * End:
   */
  