include/proto/connection.h

/*
 * include/proto/connection.h
 * This file contains connection function prototypes
 *
 * Copyright (C) 2000-2012 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_CONNECTION_H
#define _PROTO_CONNECTION_H

#include <common/config.h>
#include <common/memory.h>
#include <types/connection.h>
#include <types/listener.h>
#include <proto/obj_type.h>

extern struct pool_head *pool2_connection;

/* perform minimal intializations, report 0 in case of error, 1 if OK. */
int init_connection();

/* I/O callback for fd-based connections. It calls the read/write handlers
 * provided by the connection's sock_ops. Returns 0.
 */
int conn_fd_handler(int fd);

/* receive a PROXY protocol header over a connection */
int conn_recv_proxy(struct connection *conn, int flag);
int make_proxy_line(char *buf, int buf_len, struct sockaddr_storage *src, struct sockaddr_storage *dst);

/* calls the init() function of the transport layer if any.
 * Returns <0 in case of error.
 */
static inline int conn_xprt_init(struct connection *conn)
{
	if (conn->xprt && conn->xprt->init)
		return conn->xprt->init(conn);
	return 0;
}

/* Calls the close() function of the transport layer if any, and always unsets
 * the transport layer. However this is not done if the CO_FL_XPRT_TRACKED flag
 * is set, which allows logs to take data from the transport layer very late if
 * needed.
 */
static inline void conn_xprt_close(struct connection *conn)
{
	if (conn->xprt && !(conn->flags & CO_FL_XPRT_TRACKED)) {
		if (conn->xprt->close)
			conn->xprt->close(conn);
		conn->xprt = NULL;
	}
}

/* Update polling on connection <c>'s file descriptor depending on its current
 * state as reported in the connection's CO_FL_CURR_* flags, reports of EAGAIN
 * in CO_FL_WAIT_*, and the sock layer expectations indicated by CO_FL_SOCK_*.
 * The connection flags are updated with the new flags at the end of the
 * operation. Polling is totally disabled if an error was reported.
 */
void conn_update_sock_polling(struct connection *c);

/* Update polling on connection <c>'s file descriptor depending on its current
 * state as reported in the connection's CO_FL_CURR_* flags, reports of EAGAIN
 * in CO_FL_WAIT_*, and the data layer expectations indicated by CO_FL_DATA_*.
 * The connection flags are updated with the new flags at the end of the
 * operation. Polling is totally disabled if an error was reported.
 */
void conn_update_data_polling(struct connection *c);

/* This callback is used to send a valid PROXY protocol line to a socket being
 * established from the local machine. It sets the protocol addresses to the
 * local and remote address. This is typically used with health checks or when
 * it is not possible to determine the other end's address. It returns 0 if it
 * fails in a fatal way or needs to poll to go further, otherwise it returns
 * non-zero and removes itself from the connection's flags (the bit is provided
 * in <flag> by the caller). It is designed to be called by the connection
 * handler and relies on it to commit polling changes. Note that this function
 * expects to be able to send the whole line at once, which should always be
 * possible since it is supposed to start at the first byte of the outgoing
 * data segment.
 */
int conn_local_send_proxy(struct connection *conn, unsigned int flag);

/* inspects c->flags and returns non-zero if DATA ENA changes from the CURR ENA
 * or if the WAIT flags are set with their respective ENA flags. Additionally,
 * non-zero is also returned if an error was reported on the connection. This
 * function is used quite often and is inlined. In order to proceed optimally
 * with very little code and CPU cycles, the bits are arranged so that a change
 * can be detected by a few left shifts, a xor, and a mask. These operations
 * detect when W&D are both enabled for either direction, when C&D differ for
 * either direction and when Error is set. The trick consists in first keeping
 * only the bits we're interested in, since they don't collide when shifted,
 * and to perform the AND at the end. In practice, the compiler is able to
 * replace the last AND with a TEST in boolean conditions. This results in
 * checks that are done in 4-6 cycles and less than 30 bytes.
 */
static inline unsigned int conn_data_polling_changes(const struct connection *c)
{
	unsigned int f = c->flags;
	f &= CO_FL_DATA_WR_ENA | CO_FL_DATA_RD_ENA | CO_FL_CURR_WR_ENA |
	     CO_FL_CURR_RD_ENA | CO_FL_ERROR | CO_FL_WAIT_WR | CO_FL_WAIT_RD;

	f = (f & (f << 2)) |                         /* test W & D */
	    ((f ^ (f << 1)) & (CO_FL_CURR_WR_ENA|CO_FL_CURR_RD_ENA));    /* test C ^ D */
	return f & (CO_FL_WAIT_WR | CO_FL_WAIT_RD | CO_FL_CURR_WR_ENA | CO_FL_CURR_RD_ENA | CO_FL_ERROR);
}

/* inspects c->flags and returns non-zero if SOCK ENA changes from the CURR ENA
 * or if the WAIT flags are set with their respective ENA flags. Additionally,
 * non-zero is also returned if an error was reported on the connection. This
 * function is used quite often and is inlined. In order to proceed optimally
 * with very little code and CPU cycles, the bits are arranged so that a change
 * can be detected by a few left shifts, a xor, and a mask. These operations
 * detect when W&S are both enabled for either direction, when C&S differ for
 * either direction and when Error is set. The trick consists in first keeping
 * only the bits we're interested in, since they don't collide when shifted,
 * and to perform the AND at the end. In practice, the compiler is able to
 * replace the last AND with a TEST in boolean conditions. This results in
 * checks that are done in 4-6 cycles and less than 30 bytes.
 */
static inline unsigned int conn_sock_polling_changes(const struct connection *c)
{
	unsigned int f = c->flags;
	f &= CO_FL_SOCK_WR_ENA | CO_FL_SOCK_RD_ENA | CO_FL_CURR_WR_ENA |
	     CO_FL_CURR_RD_ENA | CO_FL_ERROR | CO_FL_WAIT_WR | CO_FL_WAIT_RD;

	f = (f & (f << 3)) |                         /* test W & S */
	    ((f ^ (f << 2)) & (CO_FL_CURR_WR_ENA|CO_FL_CURR_RD_ENA));    /* test C ^ S */
	return f & (CO_FL_WAIT_WR | CO_FL_WAIT_RD | CO_FL_CURR_WR_ENA | CO_FL_CURR_RD_ENA | CO_FL_ERROR);
}

/* Automatically updates polling on connection <c> depending on the DATA flags
 * if no handshake is in progress.
 */
static inline void conn_cond_update_data_polling(struct connection *c)
{
	if (!(c->flags & CO_FL_POLL_SOCK) && conn_data_polling_changes(c))
		conn_update_data_polling(c);
}

/* Automatically updates polling on connection <c> depending on the SOCK flags
 * if a handshake is in progress.
 */
static inline void conn_cond_update_sock_polling(struct connection *c)
{
	if ((c->flags & CO_FL_POLL_SOCK) && conn_sock_polling_changes(c))
		conn_update_sock_polling(c);
}

/* Automatically update polling on connection <c> depending on the DATA and
 * SOCK flags, and on whether a handshake is in progress or not. This may be
 * called at any moment when there is a doubt about the effectiveness of the
 * polling state, for instance when entering or leaving the handshake state.
 */
static inline void conn_cond_update_polling(struct connection *c)
{
	if (!(c->flags & CO_FL_POLL_SOCK) && conn_data_polling_changes(c))
		conn_update_data_polling(c);
	else if ((c->flags & CO_FL_POLL_SOCK) && conn_sock_polling_changes(c))
		conn_update_sock_polling(c);
}

/***** Event manipulation primitives for use by DATA I/O callbacks *****/
/* The __conn_* versions do not propagate to lower layers and are only meant
 * to be used by handlers called by the connection handler. The other ones
 * may be used anywhere.
 */
static inline void __conn_data_want_recv(struct connection *c)
{
	c->flags |= CO_FL_DATA_RD_ENA;
}

static inline void __conn_data_stop_recv(struct connection *c)
{
	c->flags &= ~CO_FL_DATA_RD_ENA;
}

static inline void __conn_data_poll_recv(struct connection *c)
{
	c->flags |= CO_FL_WAIT_RD | CO_FL_DATA_RD_ENA;
}

static inline void __conn_data_want_send(struct connection *c)
{
	c->flags |= CO_FL_DATA_WR_ENA;
}

static inline void __conn_data_stop_send(struct connection *c)
{
	c->flags &= ~CO_FL_DATA_WR_ENA;
}

static inline void __conn_data_poll_send(struct connection *c)
{
	c->flags |= CO_FL_WAIT_WR | CO_FL_DATA_WR_ENA;
}

static inline void __conn_data_stop_both(struct connection *c)
{
	c->flags &= ~(CO_FL_DATA_WR_ENA | CO_FL_DATA_RD_ENA);
}

static inline void conn_data_want_recv(struct connection *c)
{
	__conn_data_want_recv(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_stop_recv(struct connection *c)
{
	__conn_data_stop_recv(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_poll_recv(struct connection *c)
{
	__conn_data_poll_recv(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_want_send(struct connection *c)
{
	__conn_data_want_send(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_stop_send(struct connection *c)
{
	__conn_data_stop_send(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_poll_send(struct connection *c)
{
	__conn_data_poll_send(c);
	conn_cond_update_data_polling(c);
}

static inline void conn_data_stop_both(struct connection *c)
{
	__conn_data_stop_both(c);
	conn_cond_update_data_polling(c);
}

/***** Event manipulation primitives for use by handshake I/O callbacks *****/
/* The __conn_* versions do not propagate to lower layers and are only meant
 * to be used by handlers called by the connection handler. The other ones
 * may be used anywhere.
 */
static inline void __conn_sock_want_recv(struct connection *c)
{
	c->flags |= CO_FL_SOCK_RD_ENA;
}

static inline void __conn_sock_stop_recv(struct connection *c)
{
	c->flags &= ~CO_FL_SOCK_RD_ENA;
}

static inline void __conn_sock_poll_recv(struct connection *c)
{
	c->flags |= CO_FL_WAIT_RD | CO_FL_SOCK_RD_ENA;
}

static inline void __conn_sock_want_send(struct connection *c)
{
	c->flags |= CO_FL_SOCK_WR_ENA;
}

static inline void __conn_sock_stop_send(struct connection *c)
{
	c->flags &= ~CO_FL_SOCK_WR_ENA;
}

static inline void __conn_sock_poll_send(struct connection *c)
{
	c->flags |= CO_FL_WAIT_WR | CO_FL_SOCK_WR_ENA;
}

static inline void __conn_sock_stop_both(struct connection *c)
{
	c->flags &= ~(CO_FL_SOCK_WR_ENA | CO_FL_SOCK_RD_ENA);
}

static inline void conn_sock_want_recv(struct connection *c)
{
	__conn_sock_want_recv(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_stop_recv(struct connection *c)
{
	__conn_sock_stop_recv(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_poll_recv(struct connection *c)
{
	__conn_sock_poll_recv(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_want_send(struct connection *c)
{
	__conn_sock_want_send(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_stop_send(struct connection *c)
{
	__conn_sock_stop_send(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_poll_send(struct connection *c)
{
	__conn_sock_poll_send(c);
	conn_cond_update_sock_polling(c);
}

static inline void conn_sock_stop_both(struct connection *c)
{
	__conn_sock_stop_both(c);
	conn_cond_update_sock_polling(c);
}

/* shutdown management */
static inline void conn_sock_read0(struct connection *c)
{
	c->flags |= CO_FL_SOCK_RD_SH;
	__conn_sock_stop_recv(c);
}

static inline void conn_data_read0(struct connection *c)
{
	c->flags |= CO_FL_DATA_RD_SH;
	__conn_data_stop_recv(c);
}

static inline void conn_sock_shutw(struct connection *c)
{
	c->flags |= CO_FL_SOCK_WR_SH;
	__conn_sock_stop_send(c);
}

static inline void conn_data_shutw(struct connection *c)
{
	c->flags |= CO_FL_DATA_WR_SH;
	__conn_data_stop_send(c);
}

/* detect sock->data read0 transition */
static inline int conn_data_read0_pending(struct connection *c)
{
	return (c->flags & (CO_FL_DATA_RD_SH | CO_FL_SOCK_RD_SH)) == CO_FL_SOCK_RD_SH;
}

/* detect data->sock shutw transition */
static inline int conn_sock_shutw_pending(struct connection *c)
{
	return (c->flags & (CO_FL_DATA_WR_SH | CO_FL_SOCK_WR_SH)) == CO_FL_DATA_WR_SH;
}

/* Retrieves the connection's source address */
static inline void conn_get_from_addr(struct connection *conn)
{
	if (conn->flags & CO_FL_ADDR_FROM_SET)
		return;

	if (!conn->ctrl || !conn->ctrl->get_src)
		return;

	if (conn->ctrl->get_src(conn->t.sock.fd, (struct sockaddr *)&conn->addr.from,
	                        sizeof(conn->addr.from),
	                        obj_type(conn->target) != OBJ_TYPE_LISTENER) == -1)
		return;
	conn->flags |= CO_FL_ADDR_FROM_SET;
}

/* Retrieves the connection's original destination address */
static inline void conn_get_to_addr(struct connection *conn)
{
	if (conn->flags & CO_FL_ADDR_TO_SET)
		return;

	if (!conn->ctrl || !conn->ctrl->get_dst)
		return;

	if (conn->ctrl->get_dst(conn->t.sock.fd, (struct sockaddr *)&conn->addr.to,
	                        sizeof(conn->addr.to),
	                        obj_type(conn->target) != OBJ_TYPE_LISTENER) == -1)
		return;
	conn->flags |= CO_FL_ADDR_TO_SET;
}

/* Assigns a connection with the appropriate data, ctrl, transport layers, and owner. */
static inline void conn_assign(struct connection *conn, const struct data_cb *data,
                               const struct protocol *ctrl, const struct xprt_ops *xprt,
                               void *owner)
{
	conn->data = data;
	conn->ctrl = ctrl;
	conn->xprt = xprt;
	conn->owner = owner;
}

/* prepares a connection with the appropriate data, ctrl, transport layers, and
 * owner. The transport state and context are set to 0.
 */
static inline void conn_prepare(struct connection *conn, const struct data_cb *data,
                                const struct protocol *ctrl, const struct xprt_ops *xprt,
                                void *owner)
{
	conn_assign(conn, data, ctrl, xprt, owner);
	conn->xprt_st = 0;
	conn->xprt_ctx = NULL;
}

#endif /* _PROTO_CONNECTION_H */

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */