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 <types/connection.h>
#include <types/listener.h>

/* 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 */
static inline void conn_xprt_close(struct connection *conn)
{
	if (conn->xprt && conn->xprt->close)
		conn->xprt->close(conn);
}

/* 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 set new flags that were not in CURR POL. 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 simple left shift, a xor, and a mask. This operation
 * detects when POLL:DATA differs from WAIT:CURR. In order to detect the ERROR
 * flag without additional work, we remove it from the copy of the original
 * flags (unshifted) before doing the XOR. This operation is parallelized with
 * the shift and does not induce additional cycles. This explains why we check
 * the error bit shifted left in the mask. Last, the final operation is an AND
 * which the compiler is able to replace with a TEST in boolean conditions. The
 * result is that all these checks are done in 5-6 cycles only and less than 20
 * bytes.
 */
static inline unsigned int conn_data_polling_changes(const struct connection *c)
{
	unsigned int f = c->flags << 2;
	return ((c->flags & ~(CO_FL_ERROR << 2)) ^ f) &
		((CO_FL_ERROR<<2)|CO_FL_WAIT_WR|CO_FL_CURR_WR_ENA|CO_FL_WAIT_RD|CO_FL_CURR_RD_ENA) &
		~(f & (CO_FL_WAIT_WR|CO_FL_WAIT_RD));
}

/* inspects c->flags and returns non-zero if SOCK ENA changes from the CURR ENA
 * or if the WAIT flags set new flags that were not in CURR POL. 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 simple left shift, a xor, and a mask. This operation
 * detects when CURR:POLL differs from SOCK:WAIT. In order to detect the ERROR
 * flag without additional work, we remove it from the copy of the original
 * flags (unshifted) before doing the XOR. This operation is parallelized with
 * the shift and does not induce additional cycles. This explains why we check
 * the error bit shifted left in the mask. Last, the final operation is an AND
 * which the compiler is able to replace with a TEST in boolean conditions. The
 * result is that all these checks are done in 5-6 cycles only and less than 20
 * bytes.
 */
static inline unsigned int conn_sock_polling_changes(const struct connection *c)
{
	unsigned int f = c->flags << 2;
	return ((c->flags & ~(CO_FL_ERROR << 2)) ^ f) &
		((CO_FL_ERROR<<2)|CO_FL_WAIT_WR|CO_FL_SOCK_WR_ENA|CO_FL_WAIT_RD|CO_FL_SOCK_RD_ENA) &
		~(f & (CO_FL_WAIT_WR|CO_FL_WAIT_RD));
}

/* 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;
}

static inline void clear_target(struct target *dest)
{
	dest->type = TARG_TYPE_NONE;
	dest->ptr.v = NULL;
}

static inline void set_target_client(struct target *dest, struct listener *l)
{
	dest->type = TARG_TYPE_CLIENT;
	dest->ptr.l = l;
}

static inline void set_target_server(struct target *dest, struct server *s)
{
	dest->type = TARG_TYPE_SERVER;
	dest->ptr.s = s;
}

static inline void set_target_proxy(struct target *dest, struct proxy *p)
{
	dest->type = TARG_TYPE_PROXY;
	dest->ptr.p = p;
}

static inline void set_target_applet(struct target *dest, struct si_applet *a)
{
	dest->type = TARG_TYPE_APPLET;
	dest->ptr.a = a;
}

static inline void set_target_task(struct target *dest, struct task *t)
{
	dest->type = TARG_TYPE_TASK;
	dest->ptr.t = t;
}

static inline struct target *copy_target(struct target *dest, struct target *src)
{
	*dest = *src;
	return dest;
}

static inline int target_match(struct target *a, struct target *b)
{
	return a->type == b->type && a->ptr.v == b->ptr.v;
}

static inline struct server *target_srv(struct target *t)
{
	if (!t || t->type != TARG_TYPE_SERVER)
		return NULL;
	return t->ptr.s;
}

static inline struct listener *target_client(struct target *t)
{
	if (!t || t->type != TARG_TYPE_CLIENT)
		return NULL;
	return t->ptr.l;
}

/* 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),
	                         conn->target.type != TARG_TYPE_CLIENT) == -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),
	                         conn->target.type != TARG_TYPE_CLIENT) == -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:
 */