src/stream_sock.c - haproxy - Gitiles

 /*
  * Functions operating on SOCK_STREAM and buffers.
  *
  * Copyright 2000-2007 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/standard.h>
 #include <common/time.h>

 #include <types/buffers.h>
 #include <types/global.h>
 #include <types/polling.h>
 #include <types/session.h>

 #include <proto/client.h>
 #include <proto/fd.h>
 #include <proto/stream_sock.h>
 #include <proto/task.h>


 /*
  * this function is called on a read event from a stream socket.
  * It returns 0 if we have a high confidence that we will not be
  * able to read more data without polling first. Returns non-zero
  * otherwise.
  */
 int stream_sock_read(int fd) {
 	__label__ out_eternity, out_wakeup, out_error;
 	struct buffer *b = fdtab[fd].cb[DIR_RD].b;
 	int ret, max, retval;
 	int read_poll = MAX_READ_POLL_LOOPS;

 #ifdef DEBUG_FULL
 	fprintf(stderr,"stream_sock_read : fd=%d, owner=%p\n", fd, fdtab[fd].owner);
 #endif

 	retval = 1;

 	if (unlikely(fdtab[fd].ev & FD_POLL_HUP)) {
 		/* connection closed */
 		b->flags |= BF_READ_NULL;
 		goto out_eternity;
 	}
 	else if (unlikely(fdtab[fd].state == FD_STERROR || (fdtab[fd].ev & FD_POLL_ERR))) {
 		goto out_error;
 	}

 	while (1) {
 		/*
 		 * 1. compute the maximum block size we can read at once.
 		 */
 		if (b->l == 0) { /* let's realign the buffer to optimize I/O */
 			b->r = b->w = b->lr  = b->data;
 			max = b->rlim - b->data;
 		}
 		else if (b->r > b->w) {
 			max = b->rlim - b->r;
 		}
 		else {
 			max = b->w - b->r;
 			/* FIXME: theorically, if w>0, we shouldn't have rlim < data+size anymore
 			 * since it means that the rewrite protection has been removed. This
 			 * implies that the if statement can be removed.
 			 */
 			if (max > b->rlim - b->data)
 				max = b->rlim - b->data;
 		}

 		if (unlikely(max == 0)) {
 			/* Not anymore room to store data. This should theorically
 			 * never happen, but better safe than sorry !
 			 */
 			EV_FD_CLR(fd, DIR_RD);
 			goto out_eternity;
 		}

 		/*
 		 * 2. read the largest possible block
 		 */
 #ifndef MSG_NOSIGNAL
 		{
 			int skerr;
 			socklen_t lskerr = sizeof(skerr);

 			ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &skerr, &lskerr);
 			if (ret == -1 || skerr)
 				ret = -1;
 			else
 				ret = recv(fd, b->r, max, 0);
 		}
 #else
 		ret = recv(fd, b->r, max, MSG_NOSIGNAL);
 #endif
 		if (ret > 0) {
 			b->r += ret;
 			b->l += ret;
 			b->flags |= BF_PARTIAL_READ;

 			if (b->r == b->data + BUFSIZE) {
 				b->r = b->data; /* wrap around the buffer */
 			}

 			b->total += ret;

 			if (b->l == b->rlim - b->data) {
 				/* The buffer is now full, there's no point in going through
 				 * the loop again.
 				 */
 				EV_FD_CLR(fd, DIR_RD);
 				goto out_eternity;
 			}

 			/* generally if we read something smaller than the 1 or 2 MSS,
 			 * it means that it's not worth trying to read again. It may
 			 * also happen on headers, but the application then can stop
 			 * reading before we start polling.
 			 */
 			if (ret < MIN_RET_FOR_READ_LOOP)
 				break;

 			if (--read_poll <= 0)
 				break;

 		}
 		else if (ret == 0) {
 			/* connection closed */
 			b->flags |= BF_READ_NULL;
 			goto out_eternity;
 		}
 		else if (errno == EAGAIN) {
 			/* Ignore EAGAIN but inform the poller that there is
 			 * nothing to read left. But we may have done some work
 			 * justifying to notify the task.
 			 */
 			retval = 0;
 			break;
 		}
 		else {
 			goto out_error;
 		}
 	} /* while (1) */

 	/*
 	 * The only way to get out of this loop is to have stopped reading
 	 * without any error nor close, either by limiting the number of
 	 * loops, or because of an EAGAIN. We only rearm the timer if we
 	 * have at least read something.
 	 */

 	if (b->flags & BF_PARTIAL_READ) {
 		if (tv_add_ifset(&b->rex, &now, &b->rto))
 			goto out_wakeup;
 	out_eternity:
 		tv_eternity(&b->rex);
 	}

  out_wakeup:
 	if (b->flags & BF_READ_STATUS)
 		task_wakeup(fdtab[fd].owner);
 	fdtab[fd].ev &= ~FD_POLL_RD;
 	return retval;

  out_error:
 	/* There was an error. we must wakeup the task. No need to clear
 	 * the events, the task will do it.
 	 */
 	fdtab[fd].state = FD_STERROR;
 	b->flags |= BF_READ_ERROR;
 	goto out_eternity;
 }


 /*
  * this function is called on a write event from a stream socket.
  * It returns 0 if we have a high confidence that we will not be
  * able to write more data without polling first. Returns non-zero
  * otherwise.
  */
 int stream_sock_write(int fd) {
 	__label__ out_eternity, out_wakeup, out_error;
 	struct buffer *b = fdtab[fd].cb[DIR_WR].b;
 	int ret, max, retval;
 	int write_poll = MAX_WRITE_POLL_LOOPS;

 #ifdef DEBUG_FULL
 	fprintf(stderr,"stream_sock_write : fd=%d, owner=%p\n", fd, fdtab[fd].owner);
 #endif

 	retval = 1;
 	if (unlikely(fdtab[fd].state == FD_STERROR || (fdtab[fd].ev & FD_POLL_ERR)))
 		goto out_error;

 	while (1) {
 		if (b->l == 0) { /* let's realign the buffer to optimize I/O */
 			b->r = b->w = b->lr  = b->data;
 			max = 0;
 		}
 		else if (b->r > b->w) {
 			max = b->r - b->w;
 		}
 		else {
 			max = b->data + BUFSIZE - b->w;
 		}

 		if (max == 0) {
 			/* may be we have received a connection acknowledgement in TCP mode without data */
 			if (likely(fdtab[fd].state == FD_STCONN)) {
 				struct session *s = fdtab[fd].owner->context;

 				/* We have no data to send to check the connection, and
 				 * getsockopt() will not inform us whether the connection
 				 * is still pending. So we'll reuse connect() to check the
 				 * state of the socket. This has the advantage of givig us
 				 * the following info :
 				 *  - error
 				 *  - connecting (EALREADY, EINPROGRESS)
 				 *  - connected (EISCONN, 0)
 				 */
 				if ((connect(fd, (struct sockaddr *)&s->srv_addr, sizeof(s->srv_addr)) == 0))
 					errno = 0;

 				if (errno == EALREADY || errno == EINPROGRESS) {
 					retval = 0;
 					goto out_wakeup;
 				}

 				if (errno && errno != EISCONN)
 					goto out_error;

 				/* OK we just need to indicate that we got a connection
 				 * and that we wrote nothing.
 				 */
 				b->flags |= BF_WRITE_NULL;
 				fdtab[fd].state = FD_STREADY;
 			}

 			/* Funny, we were called to write something but there wasn't
 			 * anything. Theorically we cannot get there, but just in case,
 			 * let's disable the write event and pretend we never came there.
 			 */
 			EV_FD_CLR(fd, DIR_WR);
 			goto out_eternity;
 		}

 #ifndef MSG_NOSIGNAL
 		{
 			int skerr;
 			socklen_t lskerr = sizeof(skerr);

 			ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &skerr, &lskerr);
 			if (ret == -1 || skerr)
 				ret = -1;
 			else
 				ret = send(fd, b->w, max, MSG_DONTWAIT);
 		}
 #else
 		ret = send(fd, b->w, max, MSG_DONTWAIT | MSG_NOSIGNAL);
 #endif

 		if (ret > 0) {
 			b->l -= ret;
 			b->w += ret;

 			b->flags |= BF_PARTIAL_WRITE;

 			if (b->w == b->data + BUFSIZE) {
 				b->w = b->data; /* wrap around the buffer */
 			}

 			if (!b->l) {
 				EV_FD_CLR(fd, DIR_WR);
 				goto out_eternity;
 			}

 			if (--write_poll <= 0)
 				break;
 		}
 		else if (ret == 0 || errno == EAGAIN) {
 			/* nothing written, just pretend we were never called
 			 * and wait for the socket to be ready. But we may have
 			 * done some work justifying to notify the task.
 			 */
 			retval = 0;
 			break;
 		}
 		else {
 			goto out_error;
 		}
 	} /* while (1) */

 	/*
 	 * The only way to get out of this loop is to have stopped writing
 	 * without any error, either by limiting the number of loops, or
 	 * because of an EAGAIN. We only rearm the timer if we have at least
 	 * written something.
 	 */

 	if (b->flags & BF_PARTIAL_WRITE) {
 		if (tv_add_ifset(&b->wex, &now, &b->wto)) {
 			/* FIXME: to prevent the client from expiring read timeouts during writes,
 			 * we refresh it. A solution would be to merge read+write timeouts into a
 			 * unique one, although that needs some study particularly on full-duplex
 			 * TCP connections. */
 			b->rex = b->wex;
 			goto out_wakeup;
 		}
 	out_eternity:
 		tv_eternity(&b->wex);
 	}

  out_wakeup:
 	if (b->flags & BF_WRITE_STATUS)
 		task_wakeup(fdtab[fd].owner);
 	fdtab[fd].ev &= ~FD_POLL_WR;
 	return retval;

  out_error:
 	/* There was an error. we must wakeup the task. No need to clear
 	 * the events, the task will do it.
 	 */
 	fdtab[fd].state = FD_STERROR;
 	b->flags |= BF_WRITE_ERROR;
 	goto out_eternity;


 }


 /*
  * Local variables:
  *  c-indent-level: 8
  *  c-basic-offset: 8
  * End:
  */
	/*
	* Functions operating on SOCK_STREAM and buffers.
	*
	* Copyright 2000-2007 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/standard.h>
	#include <common/time.h>

	#include <types/buffers.h>
	#include <types/global.h>
	#include <types/polling.h>
	#include <types/session.h>

	#include <proto/client.h>
	#include <proto/fd.h>
	#include <proto/stream_sock.h>
	#include <proto/task.h>


	/*
	* this function is called on a read event from a stream socket.
	* It returns 0 if we have a high confidence that we will not be
	* able to read more data without polling first. Returns non-zero
	* otherwise.
	*/
	int stream_sock_read(int fd) {
	__label__ out_eternity, out_wakeup, out_error;
	struct buffer *b = fdtab[fd].cb[DIR_RD].b;
	int ret, max, retval;
	int read_poll = MAX_READ_POLL_LOOPS;

	#ifdef DEBUG_FULL
	fprintf(stderr,"stream_sock_read : fd=%d, owner=%p\n", fd, fdtab[fd].owner);
	#endif

	retval = 1;

	if (unlikely(fdtab[fd].ev & FD_POLL_HUP)) {
	/* connection closed */
	b->flags \|= BF_READ_NULL;
	goto out_eternity;
	}
	else if (unlikely(fdtab[fd].state == FD_STERROR \|\| (fdtab[fd].ev & FD_POLL_ERR))) {
	goto out_error;
	}

	while (1) {
	/*
	* 1. compute the maximum block size we can read at once.
	*/
	if (b->l == 0) { /* let's realign the buffer to optimize I/O */
	b->r = b->w = b->lr = b->data;
	max = b->rlim - b->data;
	}
	else if (b->r > b->w) {
	max = b->rlim - b->r;
	}
	else {
	max = b->w - b->r;
	/* FIXME: theorically, if w>0, we shouldn't have rlim < data+size anymore
	* since it means that the rewrite protection has been removed. This
	* implies that the if statement can be removed.
	*/
	if (max > b->rlim - b->data)
	max = b->rlim - b->data;
	}

	if (unlikely(max == 0)) {
	/* Not anymore room to store data. This should theorically
	* never happen, but better safe than sorry !
	*/
	EV_FD_CLR(fd, DIR_RD);
	goto out_eternity;
	}

	/*
	* 2. read the largest possible block
	*/
	#ifndef MSG_NOSIGNAL
	{
	int skerr;
	socklen_t lskerr = sizeof(skerr);

	ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &skerr, &lskerr);
	if (ret == -1 \|\| skerr)
	ret = -1;
	else
	ret = recv(fd, b->r, max, 0);
	}
	#else
	ret = recv(fd, b->r, max, MSG_NOSIGNAL);
	#endif
	if (ret > 0) {
	b->r += ret;
	b->l += ret;
	b->flags \|= BF_PARTIAL_READ;

	if (b->r == b->data + BUFSIZE) {
	b->r = b->data; /* wrap around the buffer */
	}

	b->total += ret;

	if (b->l == b->rlim - b->data) {
	/* The buffer is now full, there's no point in going through
	* the loop again.
	*/
	EV_FD_CLR(fd, DIR_RD);
	goto out_eternity;
	}

	/* generally if we read something smaller than the 1 or 2 MSS,
	* it means that it's not worth trying to read again. It may
	* also happen on headers, but the application then can stop
	* reading before we start polling.
	*/
	if (ret < MIN_RET_FOR_READ_LOOP)
	break;

	if (--read_poll <= 0)
	break;

	}
	else if (ret == 0) {
	/* connection closed */
	b->flags \|= BF_READ_NULL;
	goto out_eternity;
	}
	else if (errno == EAGAIN) {
	/* Ignore EAGAIN but inform the poller that there is
	* nothing to read left. But we may have done some work
	* justifying to notify the task.
	*/
	retval = 0;
	break;
	}
	else {
	goto out_error;
	}
	} /* while (1) */

	/*
	* The only way to get out of this loop is to have stopped reading
	* without any error nor close, either by limiting the number of
	* loops, or because of an EAGAIN. We only rearm the timer if we
	* have at least read something.
	*/

	if (b->flags & BF_PARTIAL_READ) {
	if (tv_add_ifset(&b->rex, &now, &b->rto))
	goto out_wakeup;
	out_eternity:
	tv_eternity(&b->rex);
	}

	out_wakeup:
	if (b->flags & BF_READ_STATUS)
	task_wakeup(fdtab[fd].owner);
	fdtab[fd].ev &= ~FD_POLL_RD;
	return retval;

	out_error:
	/* There was an error. we must wakeup the task. No need to clear
	* the events, the task will do it.
	*/
	fdtab[fd].state = FD_STERROR;
	b->flags \|= BF_READ_ERROR;
	goto out_eternity;
	}


	/*
	* this function is called on a write event from a stream socket.
	* It returns 0 if we have a high confidence that we will not be
	* able to write more data without polling first. Returns non-zero
	* otherwise.
	*/
	int stream_sock_write(int fd) {
	__label__ out_eternity, out_wakeup, out_error;
	struct buffer *b = fdtab[fd].cb[DIR_WR].b;
	int ret, max, retval;
	int write_poll = MAX_WRITE_POLL_LOOPS;

	#ifdef DEBUG_FULL
	fprintf(stderr,"stream_sock_write : fd=%d, owner=%p\n", fd, fdtab[fd].owner);
	#endif

	retval = 1;
	if (unlikely(fdtab[fd].state == FD_STERROR \|\| (fdtab[fd].ev & FD_POLL_ERR)))
	goto out_error;

	while (1) {
	if (b->l == 0) { /* let's realign the buffer to optimize I/O */
	b->r = b->w = b->lr = b->data;
	max = 0;
	}
	else if (b->r > b->w) {
	max = b->r - b->w;
	}
	else {
	max = b->data + BUFSIZE - b->w;
	}

	if (max == 0) {
	/* may be we have received a connection acknowledgement in TCP mode without data */
	if (likely(fdtab[fd].state == FD_STCONN)) {
	struct session *s = fdtab[fd].owner->context;

	/* We have no data to send to check the connection, and
	* getsockopt() will not inform us whether the connection
	* is still pending. So we'll reuse connect() to check the
	* state of the socket. This has the advantage of givig us
	* the following info :
	* - error
	* - connecting (EALREADY, EINPROGRESS)
	* - connected (EISCONN, 0)
	*/
	if ((connect(fd, (struct sockaddr *)&s->srv_addr, sizeof(s->srv_addr)) == 0))
	errno = 0;

	if (errno == EALREADY \|\| errno == EINPROGRESS) {
	retval = 0;
	goto out_wakeup;
	}

	if (errno && errno != EISCONN)
	goto out_error;

	/* OK we just need to indicate that we got a connection
	* and that we wrote nothing.
	*/
	b->flags \|= BF_WRITE_NULL;
	fdtab[fd].state = FD_STREADY;
	}

	/* Funny, we were called to write something but there wasn't
	* anything. Theorically we cannot get there, but just in case,
	* let's disable the write event and pretend we never came there.
	*/
	EV_FD_CLR(fd, DIR_WR);
	goto out_eternity;
	}

	#ifndef MSG_NOSIGNAL
	{
	int skerr;
	socklen_t lskerr = sizeof(skerr);

	ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &skerr, &lskerr);
	if (ret == -1 \|\| skerr)
	ret = -1;
	else
	ret = send(fd, b->w, max, MSG_DONTWAIT);
	}
	#else
	ret = send(fd, b->w, max, MSG_DONTWAIT \| MSG_NOSIGNAL);
	#endif

	if (ret > 0) {
	b->l -= ret;
	b->w += ret;

	b->flags \|= BF_PARTIAL_WRITE;

	if (b->w == b->data + BUFSIZE) {
	b->w = b->data; /* wrap around the buffer */
	}

	if (!b->l) {
	EV_FD_CLR(fd, DIR_WR);
	goto out_eternity;
	}

	if (--write_poll <= 0)
	break;
	}
	else if (ret == 0 \|\| errno == EAGAIN) {
	/* nothing written, just pretend we were never called
	* and wait for the socket to be ready. But we may have
	* done some work justifying to notify the task.
	*/
	retval = 0;
	break;
	}
	else {
	goto out_error;
	}
	} /* while (1) */

	/*
	* The only way to get out of this loop is to have stopped writing
	* without any error, either by limiting the number of loops, or
	* because of an EAGAIN. We only rearm the timer if we have at least
	* written something.
	*/

	if (b->flags & BF_PARTIAL_WRITE) {
	if (tv_add_ifset(&b->wex, &now, &b->wto)) {
	/* FIXME: to prevent the client from expiring read timeouts during writes,
	* we refresh it. A solution would be to merge read+write timeouts into a
	* unique one, although that needs some study particularly on full-duplex
	* TCP connections. */
	b->rex = b->wex;
	goto out_wakeup;
	}
	out_eternity:
	tv_eternity(&b->wex);
	}

	out_wakeup:
	if (b->flags & BF_WRITE_STATUS)
	task_wakeup(fdtab[fd].owner);
	fdtab[fd].ev &= ~FD_POLL_WR;
	return retval;

	out_error:
	/* There was an error. we must wakeup the task. No need to clear
	* the events, the task will do it.
	*/
	fdtab[fd].state = FD_STERROR;
	b->flags \|= BF_WRITE_ERROR;
	goto out_eternity;


	}



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