haproxy/src/stream_interface.c

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[MAJOR] add a connection error state to the stream_interface Tracking connection status changes was hard, and some code was redundant. A new SI_ST_CER state was added to the stream interface to indicate a past connection error, and an SI_FL_ERR flag was added to report past I/O error. The stream_sock code does not set the connection to SI_ST_CLO anymore in case of I/O error, it's the upper layer which does it. This makes it possible to know exactly when the file descriptors are allocated. The new SI_ST_CER state permitted to split tcp_connection_status() in two parts, one processing SI_ST_CON and the other one SI_ST_CER. Synchronous connection errors now make use of this last state, hence eliminating duplicate code. Some ib<->ob copy paste errors were found and fixed, and all entities setting SI_ST_CLO also shut the buffers down. Some of these stream_interface specific functions and structures have migrated to a new stream_interface.c file. Some types of errors are still not detected by the buffers. For instance, let's assume the following scenario in one single pass of process_session: a connection sits in SI_ST_TAR state during a retry. At TAR expiration, a new connection attempt is made, the connection is obtained and srv->cur_sess is increased. Then the buffer timeout is fires and everything is cleared, the new state becomes SI_ST_CLO. The cleaning code checks that previous state was either SI_ST_CON or SI_ST_EST to release the connection. But that's wrong because last state is still SI_ST_TAR. So the server's connection count does not get decreased. This means that prev_state must not be used, and must be replaced by some transition detection instead of level detection. The following debugging line was useful to track state changes : fprintf(stderr, "%s:%d: cs=%d ss=%d(%d) rqf=0x%08x rpf=0x%08x\n", __FUNCTION__, __LINE__, s->si[0].state, s->si[1].state, s->si[1].err_type, s->req->flags, s-> rep->flags);
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/*
* Functions managing stream_interface structures
*
* Copyright 2000-2008 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 <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/standard.h>
#include <common/ticks.h>
#include <common/time.h>
#include <proto/buffers.h>
#include <proto/client.h>
#include <proto/fd.h>
#include <proto/stream_sock.h>
#include <proto/task.h>
/*
* This function only has to be called once after a wakeup event in case of
* suspected timeout. It controls the stream interface timeouts and sets
* si->flags accordingly. It does NOT close anything, as this timeout may
* be used for any purpose. It returns 1 if the timeout fired, otherwise
* zero.
*/
int stream_int_check_timeouts(struct stream_interface *si)
{
if (tick_is_expired(si->exp, now_ms)) {
si->flags |= SI_FL_EXP;
return 1;
}
return 0;
}
/* to be called only when in SI_ST_DIS with SI_FL_ERR */
[MAJOR] add a connection error state to the stream_interface Tracking connection status changes was hard, and some code was redundant. A new SI_ST_CER state was added to the stream interface to indicate a past connection error, and an SI_FL_ERR flag was added to report past I/O error. The stream_sock code does not set the connection to SI_ST_CLO anymore in case of I/O error, it's the upper layer which does it. This makes it possible to know exactly when the file descriptors are allocated. The new SI_ST_CER state permitted to split tcp_connection_status() in two parts, one processing SI_ST_CON and the other one SI_ST_CER. Synchronous connection errors now make use of this last state, hence eliminating duplicate code. Some ib<->ob copy paste errors were found and fixed, and all entities setting SI_ST_CLO also shut the buffers down. Some of these stream_interface specific functions and structures have migrated to a new stream_interface.c file. Some types of errors are still not detected by the buffers. For instance, let's assume the following scenario in one single pass of process_session: a connection sits in SI_ST_TAR state during a retry. At TAR expiration, a new connection attempt is made, the connection is obtained and srv->cur_sess is increased. Then the buffer timeout is fires and everything is cleared, the new state becomes SI_ST_CLO. The cleaning code checks that previous state was either SI_ST_CON or SI_ST_EST to release the connection. But that's wrong because last state is still SI_ST_TAR. So the server's connection count does not get decreased. This means that prev_state must not be used, and must be replaced by some transition detection instead of level detection. The following debugging line was useful to track state changes : fprintf(stderr, "%s:%d: cs=%d ss=%d(%d) rqf=0x%08x rpf=0x%08x\n", __FUNCTION__, __LINE__, s->si[0].state, s->si[1].state, s->si[1].err_type, s->req->flags, s-> rep->flags);
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void stream_int_report_error(struct stream_interface *si)
{
if (!si->err_type)
si->err_type = SI_ET_DATA_ERR;
si->ob->flags |= BF_WRITE_ERROR;
si->ib->flags |= BF_READ_ERROR;
}
/*
* Returns a message into the output buffer, and flushes the input buffer. The
* output buffer doesn't need to be empty before this. The message is contained
* in a "chunk". If it is null, then an empty message is used.
*/
void stream_int_return(struct stream_interface *si, const struct chunk *msg)
{
buffer_flush(si->ib);
buffer_flush(si->ob);
if (msg && msg->len)
buffer_write(si->ob, msg->str, msg->len);
}
/*
* Returns a message to the client ; the connection is shut down for read,
* and the request is cleared so that no server connection can be initiated.
* The buffer is marked for read shutdown on the other side to protect the
* message, and the buffer write is enabled. The message is contained in a
* "chunk". If it is null, then an empty message is used. The reply buffer
* doesn't need to be empty before this. The goal of this function is to
* return error messages to a client.
*/
void stream_int_retnclose(struct stream_interface *si, const struct chunk *msg)
{
buffer_abort(si->ib);
buffer_flush(si->ob);
buffer_shutr_now(si->ob);
if (msg && msg->len)
buffer_write(si->ob, msg->str, msg->len);
si->ob->wex = tick_add_ifset(now_ms, si->ob->wto);
buffer_write_ena(si->ob);
}
[MAJOR] add a connection error state to the stream_interface Tracking connection status changes was hard, and some code was redundant. A new SI_ST_CER state was added to the stream interface to indicate a past connection error, and an SI_FL_ERR flag was added to report past I/O error. The stream_sock code does not set the connection to SI_ST_CLO anymore in case of I/O error, it's the upper layer which does it. This makes it possible to know exactly when the file descriptors are allocated. The new SI_ST_CER state permitted to split tcp_connection_status() in two parts, one processing SI_ST_CON and the other one SI_ST_CER. Synchronous connection errors now make use of this last state, hence eliminating duplicate code. Some ib<->ob copy paste errors were found and fixed, and all entities setting SI_ST_CLO also shut the buffers down. Some of these stream_interface specific functions and structures have migrated to a new stream_interface.c file. Some types of errors are still not detected by the buffers. For instance, let's assume the following scenario in one single pass of process_session: a connection sits in SI_ST_TAR state during a retry. At TAR expiration, a new connection attempt is made, the connection is obtained and srv->cur_sess is increased. Then the buffer timeout is fires and everything is cleared, the new state becomes SI_ST_CLO. The cleaning code checks that previous state was either SI_ST_CON or SI_ST_EST to release the connection. But that's wrong because last state is still SI_ST_TAR. So the server's connection count does not get decreased. This means that prev_state must not be used, and must be replaced by some transition detection instead of level detection. The following debugging line was useful to track state changes : fprintf(stderr, "%s:%d: cs=%d ss=%d(%d) rqf=0x%08x rpf=0x%08x\n", __FUNCTION__, __LINE__, s->si[0].state, s->si[1].state, s->si[1].err_type, s->req->flags, s-> rep->flags);
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/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/