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/*
* include/proto/channel.h
* Channel management definitions, macros and inline functions.
*
* Copyright (C) 2000-2014 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_CHANNEL_H
#define _PROTO_CHANNEL_H
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <common/config.h>
#include <common/chunk.h>
#include <common/ticks.h>
#include <common/time.h>
#include <types/channel.h>
#include <types/global.h>
#include <types/stream.h>
#include <types/stream_interface.h>
#include <proto/applet.h>
#include <proto/task.h>
/* perform minimal intializations, report 0 in case of error, 1 if OK. */
int init_channel();
unsigned long long __channel_forward(struct channel *chn, unsigned long long bytes);
/* SI-to-channel functions working with buffers */
int ci_putblk(struct channel *chn, const char *str, int len);
struct buffer *ci_swpbuf(struct channel *chn, struct buffer *buf);
int ci_putchr(struct channel *chn, char c);
int ci_getline_nc(const struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
int ci_getblk_nc(const struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
int co_inject(struct channel *chn, const char *msg, int len);
int co_getline(const struct channel *chn, char *str, int len);
int co_getblk(const struct channel *chn, char *blk, int len, int offset);
int co_getline_nc(const struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
int co_getblk_nc(const struct channel *chn, char **blk1, int *len1, char **blk2, int *len2);
/* returns a pointer to the stream the channel belongs to */
static inline struct stream *chn_strm(const struct channel *chn)
{
if (chn->flags & CF_ISRESP)
return LIST_ELEM(chn, struct stream *, res);
else
return LIST_ELEM(chn, struct stream *, req);
}
/* returns a pointer to the stream interface feeding the channel (producer) */
static inline struct stream_interface *chn_prod(const struct channel *chn)
{
if (chn->flags & CF_ISRESP)
return &LIST_ELEM(chn, struct stream *, res)->si[1];
else
return &LIST_ELEM(chn, struct stream *, req)->si[0];
}
/* returns a pointer to the stream interface consuming the channel (producer) */
static inline struct stream_interface *chn_cons(const struct channel *chn)
{
if (chn->flags & CF_ISRESP)
return &LIST_ELEM(chn, struct stream *, res)->si[0];
else
return &LIST_ELEM(chn, struct stream *, req)->si[1];
}
/* Initialize all fields in the channel. */
static inline void channel_init(struct channel *chn)
{
chn->buf = &buf_empty;
chn->to_forward = 0;
chn->last_read = now_ms;
chn->xfer_small = chn->xfer_large = 0;
chn->total = 0;
chn->pipe = NULL;
chn->analysers = 0;
chn->flags = 0;
}
/* Schedule up to <bytes> more bytes to be forwarded via the channel without
* notifying the owner task. Any data pending in the buffer are scheduled to be
* sent as well, in the limit of the number of bytes to forward. This must be
* the only method to use to schedule bytes to be forwarded. If the requested
* number is too large, it is automatically adjusted. The number of bytes taken
* into account is returned. Directly touching ->to_forward will cause lockups
* when buf->o goes down to zero if nobody is ready to push the remaining data.
*/
static inline unsigned long long channel_forward(struct channel *chn, unsigned long long bytes)
{
/* hint: avoid comparisons on long long for the fast case, since if the
* length does not fit in an unsigned it, it will never be forwarded at
* once anyway.
*/
if (bytes <= ~0U) {
unsigned int bytes32 = bytes;
if (bytes32 <= chn->buf->i) {
/* OK this amount of bytes might be forwarded at once */
b_adv(chn->buf, bytes32);
return bytes;
}
}
return __channel_forward(chn, bytes);
}
/* Forwards any input data and marks the channel for permanent forwarding */
static inline void channel_forward_forever(struct channel *chn)
{
b_adv(chn->buf, chn->buf->i);
chn->to_forward = CHN_INFINITE_FORWARD;
}
/*********************************************************************/
/* These functions are used to compute various channel content sizes */
/*********************************************************************/
/* Reports non-zero if the channel is empty, which means both its
* buffer and pipe are empty. The construct looks strange but is
* jump-less and much more efficient on both 32 and 64-bit than
* the boolean test.
*/
static inline unsigned int channel_is_empty(const struct channel *c)
{
return !(c->buf->o | (long)c->pipe);
}
/* Returns non-zero if the channel is rewritable, which means that the buffer
* it is attached to has at least <maxrewrite> bytes immediately available.
* This is used to decide when a request or response may be parsed when some
* data from a previous exchange might still be present.
*/
static inline int channel_is_rewritable(const struct channel *chn)
{
int rem = chn->buf->size;
rem -= chn->buf->o;
rem -= chn->buf->i;
rem -= global.tune.maxrewrite;
return rem >= 0;
}
/* Tells whether data are likely to leave the buffer. This is used to know when
* we can safely ignore the reserve since we know we cannot retry a connection.
* It returns zero if data are blocked, non-zero otherwise.
*/
static inline int channel_may_send(const struct channel *chn)
{
return chn_cons(chn)->state == SI_ST_EST;
}
/* Returns non-zero if the channel can still receive data. This is used to
* decide when to stop reading into a buffer when we want to ensure that we
* leave the reserve untouched after all pending outgoing data are forwarded.
* The reserved space is taken into account if ->to_forward indicates that an
* end of transfer is close to happen. Note that both ->buf->o and ->to_forward
* are considered as available since they're supposed to leave the buffer. The
* test is optimized to avoid as many operations as possible for the fast case
* and to be used as an "if" condition. Just like channel_recv_limit(), we
* never allow to overwrite the reserve until the output stream interface is
* connected, otherwise we could spin on a POST with http-send-name-header.
*/
static inline int channel_may_recv(const struct channel *chn)
{
int rem = chn->buf->size;
if (chn->buf == &buf_empty)
return 1;
rem -= chn->buf->o;
rem -= chn->buf->i;
if (!rem)
return 0; /* buffer already full */
if (rem > global.tune.maxrewrite)
return 1; /* reserve not yet reached */
if (!channel_may_send(chn))
return 0; /* don't touch reserve until we can send */
/* Now we know there's some room left in the reserve and we may
* forward. As long as i-to_fwd < size-maxrw, we may still
* receive. This is equivalent to i+maxrw-size < to_fwd,
* which is logical since i+maxrw-size is what overlaps with
* the reserve, and we want to ensure they're covered by scheduled
* forwards.
*/
rem = chn->buf->i + global.tune.maxrewrite - chn->buf->size;
return rem < 0 || (unsigned int)rem < chn->to_forward;
}
/* Returns true if the channel's input is already closed */
static inline int channel_input_closed(struct channel *chn)
{
return ((chn->flags & CF_SHUTR) != 0);
}
/* Returns true if the channel's output is already closed */
static inline int channel_output_closed(struct channel *chn)
{
return ((chn->flags & CF_SHUTW) != 0);
}
/* Check channel timeouts, and set the corresponding flags. The likely/unlikely
* have been optimized for fastest normal path. The read/write timeouts are not
* set if there was activity on the channel. That way, we don't have to update
* the timeout on every I/O. Note that the analyser timeout is always checked.
*/
static inline void channel_check_timeouts(struct channel *chn)
{
if (likely(!(chn->flags & (CF_SHUTR|CF_READ_TIMEOUT|CF_READ_ACTIVITY|CF_READ_NOEXP))) &&
unlikely(tick_is_expired(chn->rex, now_ms)))
chn->flags |= CF_READ_TIMEOUT;
if (likely(!(chn->flags & (CF_SHUTW|CF_WRITE_TIMEOUT|CF_WRITE_ACTIVITY))) &&
unlikely(tick_is_expired(chn->wex, now_ms)))
chn->flags |= CF_WRITE_TIMEOUT;
if (likely(!(chn->flags & CF_ANA_TIMEOUT)) &&
unlikely(tick_is_expired(chn->analyse_exp, now_ms)))
chn->flags |= CF_ANA_TIMEOUT;
}
/* Erase any content from channel <buf> and adjusts flags accordingly. Note
* that any spliced data is not affected since we may not have any access to
* it.
*/
static inline void channel_erase(struct channel *chn)
{
chn->to_forward = 0;
b_reset(chn->buf);
}
/* marks the channel as "shutdown" ASAP for reads */
static inline void channel_shutr_now(struct channel *chn)
{
chn->flags |= CF_SHUTR_NOW;
}
/* marks the channel as "shutdown" ASAP for writes */
static inline void channel_shutw_now(struct channel *chn)
{
chn->flags |= CF_SHUTW_NOW;
}
/* marks the channel as "shutdown" ASAP in both directions */
static inline void channel_abort(struct channel *chn)
{
chn->flags |= CF_SHUTR_NOW | CF_SHUTW_NOW;
chn->flags &= ~CF_AUTO_CONNECT;
}
/* allow the consumer to try to establish a new connection. */
static inline void channel_auto_connect(struct channel *chn)
{
chn->flags |= CF_AUTO_CONNECT;
}
/* prevent the consumer from trying to establish a new connection, and also
* disable auto shutdown forwarding.
*/
static inline void channel_dont_connect(struct channel *chn)
{
chn->flags &= ~(CF_AUTO_CONNECT|CF_AUTO_CLOSE);
}
/* allow the producer to forward shutdown requests */
static inline void channel_auto_close(struct channel *chn)
{
chn->flags |= CF_AUTO_CLOSE;
}
/* prevent the producer from forwarding shutdown requests */
static inline void channel_dont_close(struct channel *chn)
{
chn->flags &= ~CF_AUTO_CLOSE;
}
/* allow the producer to read / poll the input */
static inline void channel_auto_read(struct channel *chn)
{
chn->flags &= ~CF_DONT_READ;
}
/* prevent the producer from read / poll the input */
static inline void channel_dont_read(struct channel *chn)
{
chn->flags |= CF_DONT_READ;
}
/*************************************************/
/* Buffer operations in the context of a channel */
/*************************************************/
/* Return the max number of bytes the buffer can contain so that once all the
* pending bytes are forwarded, the buffer still has global.tune.maxrewrite
* bytes free. The result sits between chn->size - maxrewrite and chn->size.
* It is important to mention that if buf->i is already larger than size-maxrw
* the condition above cannot be satisfied and the lowest size will be returned
* anyway. The principles are the following :
* 0) the empty buffer has a limit of zero
* 1) a non-connected buffer cannot touch the reserve
* 2) infinite forward can always fill the buffer since all data will leave
* 3) all output bytes are considered in transit since they're leaving
* 4) all input bytes covered by to_forward are considered in transit since
* they'll be converted to output bytes.
* 5) all input bytes not covered by to_forward as considered remaining
* 6) all bytes scheduled to be forwarded minus what is already in the input
* buffer will be in transit during future rounds.
* 7) 4+5+6 imply that the amount of input bytes (i) is irrelevant to the max
* usable length, only to_forward and output count. The difference is
* visible when to_forward > i.
* 8) the reserve may be covered up to the amount of bytes in transit since
* these bytes will only take temporary space.
*
* A typical buffer looks like this :
*
* <-------------- max_len ----------->
* <---- o ----><----- i -----> <--- 0..maxrewrite --->
* +------------+--------------+-------+----------------------+
* |////////////|\\\\\\\\\\\\\\|xxxxxxx| reserve |
* +------------+--------+-----+-------+----------------------+
* <- fwd -> <-avail->
*
* Or when to_forward > i :
*
* <-------------- max_len ----------->
* <---- o ----><----- i -----> <--- 0..maxrewrite --->
* +------------+--------------+-------+----------------------+
* |////////////|\\\\\\\\\\\\\\|xxxxxxx| reserve |
* +------------+--------+-----+-------+----------------------+
* <-avail->
* <------------------ fwd ---------------->
*
* - the amount of buffer bytes in transit is : min(i, fwd) + o
* - some scheduled bytes may be in transit (up to fwd - i)
* - the reserve is max(0, maxrewrite - transit)
* - the maximum usable buffer length is size - reserve.
* - the available space is max_len - i - o
*
* So the formula to compute the buffer's maximum length to protect the reserve
* when reading new data is :
*
* max = size - maxrewrite + min(maxrewrite, transit)
* = size - max(maxrewrite - transit, 0)
*
* But WARNING! The conditions might change during the transfer and it could
* very well happen that a buffer would contain more bytes than max_len due to
* i+o already walking over the reserve (eg: after a header rewrite), including
* i or o alone hitting the limit. So it is critical to always consider that
* bounds may have already been crossed and that available space may be negative
* for example. Due to this it is perfectly possible for this function to return
* a value that is lower than current i+o.
*/
static inline int channel_recv_limit(const struct channel *chn)
{
unsigned int transit;
int reserve;
/* return zero if empty */
reserve = chn->buf->size;
if (chn->buf == &buf_empty)
goto end;
/* return size - maxrewrite if we can't send */
reserve = global.tune.maxrewrite;
if (unlikely(!channel_may_send(chn)))
goto end;
/* We need to check what remains of the reserve after o and to_forward
* have been transmitted, but they can overflow together and they can
* cause an integer underflow in the comparison since both are unsigned
* while maxrewrite is signed.
* The code below has been verified for being a valid check for this :
* - if (o + to_forward) overflow => return size [ large enough ]
* - if o + to_forward >= maxrw => return size [ large enough ]
* - otherwise return size - (maxrw - (o + to_forward))
*/
transit = chn->buf->o + chn->to_forward;
reserve -= transit;
if (transit < chn->to_forward || // addition overflow
transit >= (unsigned)global.tune.maxrewrite) // enough transit data
return chn->buf->size;
end:
return chn->buf->size - reserve;
}
/* Returns the amount of space available at the input of the buffer, taking the
* reserved space into account if ->to_forward indicates that an end of transfer
* is close to happen. The test is optimized to avoid as many operations as
* possible for the fast case.
*/
static inline int channel_recv_max(const struct channel *chn)
{
int ret;
ret = channel_recv_limit(chn) - chn->buf->i - chn->buf->o;
if (ret < 0)
ret = 0;
return ret;
}
/* Allocates a buffer for channel <chn>, but only if it's guaranteed that it's
* not the last available buffer or it's the response buffer. Unless the buffer
* is the response buffer, an extra control is made so that we always keep
* <tune.buffers.reserved> buffers available after this allocation. Returns 0 in
* case of failure, non-zero otherwise.
*
* If no buffer are available, the requester, represented by <wait> pointer,
* will be added in the list of objects waiting for an available buffer.
*/
static inline int channel_alloc_buffer(struct channel *chn, struct buffer_wait *wait)
{
int margin = 0;
if (!(chn->flags & CF_ISRESP))
margin = global.tune.reserved_bufs;
if (b_alloc_margin(&chn->buf, margin) != NULL)
return 1;
if (LIST_ISEMPTY(&wait->list))
LIST_ADDQ(&buffer_wq, &wait->list);
return 0;
}
/* Releases a possibly allocated buffer for channel <chn>. If it was not
* allocated, this function does nothing. Else the buffer is released and we try
* to wake up as many streams/applets as possible. */
static inline void channel_release_buffer(struct channel *chn, struct buffer_wait *wait)
{
if (chn->buf->size && buffer_empty(chn->buf)) {
b_free(&chn->buf);
offer_buffers(wait->target, tasks_run_queue + applets_active_queue);
}
}
/* Truncate any unread data in the channel's buffer, and disable forwarding.
* Outgoing data are left intact. This is mainly to be used to send error
* messages after existing data.
*/
static inline void channel_truncate(struct channel *chn)
{
if (!chn->buf->o)
return channel_erase(chn);
chn->to_forward = 0;
if (!chn->buf->i)
return;
chn->buf->i = 0;
}
/*
* Advance the channel buffer's read pointer by <len> bytes. This is useful
* when data have been read directly from the buffer. It is illegal to call
* this function with <len> causing a wrapping at the end of the buffer. It's
* the caller's responsibility to ensure that <len> is never larger than
* chn->o. Channel flag WRITE_PARTIAL is set.
*/
static inline void co_skip(struct channel *chn, int len)
{
chn->buf->o -= len;
if (buffer_empty(chn->buf))
chn->buf->p = chn->buf->data;
/* notify that some data was written to the SI from the buffer */
chn->flags |= CF_WRITE_PARTIAL;
}
/* Tries to copy chunk <chunk> into the channel's buffer after length controls.
* The chn->o and to_forward pointers are updated. If the channel's input is
* closed, -2 is returned. If the block is too large for this buffer, -3 is
* returned. If there is not enough room left in the buffer, -1 is returned.
* Otherwise the number of bytes copied is returned (0 being a valid number).
* Channel flag READ_PARTIAL is updated if some data can be transferred. The
* chunk's length is updated with the number of bytes sent.
*/
static inline int ci_putchk(struct channel *chn, struct chunk *chunk)
{
int ret;
ret = ci_putblk(chn, chunk->str, chunk->len);
if (ret > 0)
chunk->len -= ret;
return ret;
}
/* Tries to copy string <str> at once into the channel's buffer after length
* controls. The chn->o and to_forward pointers are updated. If the channel's
* input is closed, -2 is returned. If the block is too large for this buffer,
* -3 is returned. If there is not enough room left in the buffer, -1 is
* returned. Otherwise the number of bytes copied is returned (0 being a valid
* number). Channel flag READ_PARTIAL is updated if some data can be
* transferred.
*/
static inline int ci_putstr(struct channel *chn, const char *str)
{
return ci_putblk(chn, str, strlen(str));
}
/*
* Return one char from the channel's buffer. If the buffer is empty and the
* channel is closed, return -2. If the buffer is just empty, return -1. The
* buffer's pointer is not advanced, it's up to the caller to call co_skip(buf,
* 1) when it has consumed the char. Also note that this function respects the
* chn->o limit.
*/
static inline int co_getchr(struct channel *chn)
{
/* closed or empty + imminent close = -2; empty = -1 */
if (unlikely((chn->flags & CF_SHUTW) || channel_is_empty(chn))) {
if (chn->flags & (CF_SHUTW|CF_SHUTW_NOW))
return -2;
return -1;
}
return *buffer_wrap_sub(chn->buf, chn->buf->p - chn->buf->o);
}
#endif /* _PROTO_CHANNEL_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/