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/*
* 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/debug.h>
#include <common/standard.h>
#include <common/time.h>
#include <types/buffers.h>
#include <types/global.h>
#include <types/polling.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_shutdown_r, out_error;
struct buffer *b = fdtab[fd].cb[DIR_RD].b;
int ret, max, retval, cur_read;
int read_poll = MAX_READ_POLL_LOOPS;
#ifdef DEBUG_FULL
fprintf(stderr,"stream_sock_read : fd=%d, ev=0x%02x, owner=%p\n", fd, fdtab[fd].ev, fdtab[fd].owner);
#endif
retval = 1;
/* stop immediately on errors */
if (fdtab[fd].state == FD_STERROR || (fdtab[fd].ev & FD_POLL_ERR))
goto out_error;
/* stop here if we reached the end of data */
if ((fdtab[fd].ev & (FD_POLL_IN|FD_POLL_HUP)) == FD_POLL_HUP)
goto out_shutdown_r;
cur_read = 0;
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;
cur_read += 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.
*/
if (!(b->flags & BF_STREAMER_FAST) && (cur_read == b->l)) {
b->xfer_small = 0;
b->xfer_large++;
if (b->xfer_large >= 3) {
/* we call this buffer a fast streamer if it manages
* to be filled in one call 3 consecutive times.
*/
b->flags |= (BF_STREAMER | BF_STREAMER_FAST);
//fputc('+', stderr);
}
}
else if ((b->flags & (BF_STREAMER | BF_STREAMER_FAST)) &&
(cur_read <= BUFSIZE / 2)) {
b->xfer_large = 0;
b->xfer_small++;
if (b->xfer_small >= 2) {
/* if the buffer has been at least half full twice,
* we receive faster than we send, so at least it
* is not a "fast streamer".
*/
b->flags &= ~BF_STREAMER_FAST;
//fputc('-', stderr);
}
}
else {
b->xfer_small = 0;
b->xfer_large = 0;
}
EV_FD_CLR(fd, DIR_RD);
goto out_eternity;
}
/* if too many bytes were missing from last read, it means that
* it's pointless trying to read again because the system does
* not have them in buffers. BTW, if FD_POLL_HUP was present,
* it means that we have reached the end and that the connection
* is closed.
*/
if (ret < max) {
if ((b->flags & (BF_STREAMER | BF_STREAMER_FAST)) &&
(cur_read <= BUFSIZE / 2)) {
b->xfer_large = 0;
b->xfer_small++;
if (b->xfer_small >= 3) {
/* we have read less than half of the buffer in
* one pass, and this happened at least 3 times.
* This is definitely not a streamer.
*/
b->flags &= ~(BF_STREAMER | BF_STREAMER_FAST);
//fputc('!', stderr);
}
}
if (fdtab[fd].ev & FD_POLL_HUP)
goto out_shutdown_r;
break;
}
/* generally if we read something smaller than 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 */
goto out_shutdown_r;
}
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_IN;
return retval;
out_shutdown_r:
fdtab[fd].ev &= ~FD_POLL_HUP;
b->flags |= BF_READ_NULL;
goto out_eternity;
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;
fdtab[fd].ev &= ~FD_POLL_STICKY;
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 (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)) {
/* 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, fdtab[fd].peeraddr, fdtab[fd].peerlen) == 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 the system buffer is full, don't insist */
if (ret < max)
break;
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. */
if (!(b->flags & BF_SHUTR_STATUS))
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_OUT;
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;
fdtab[fd].ev &= ~FD_POLL_STICKY;
b->flags |= BF_WRITE_ERROR;
goto out_eternity;
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/