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/*
* IRC - Internet Relay Chat, ircd/msgq.c
* Copyright (C) 2000 Kevin L. Mitchell <klmitch@mit.edu>
*
* 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 1, or (at your option)
* any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file
* @brief Outbound message queue implementation.
* @version $Id: msgq.c 1627 2006-03-14 03:56:58Z entrope $
*/
#include "config.h"
#include "msgq.h"
#include "ircd.h"
#include "ircd_alloc.h"
#include "ircd_defs.h"
#include "ircd_features.h"
#include "ircd_log.h"
#include "ircd_reply.h"
#include "ircd_snprintf.h"
#include "numeric.h"
#include "send.h"
#include "s_debug.h"
#include "s_stats.h"
/* #include <assert.h> -- Now using assert in ircd_log.h */
#include <stdarg.h>
#include <string.h>
#include <sys/types.h>
#include <sys/uio.h> /* struct iovec */
#define MB_BASE_SHIFT 5 /**< Log2 of smallest message body to allocate. */
#define MB_MAX_SHIFT 9 /**< Log2 of largest message body to allocate. */
/** Buffer for a single message. */
struct MsgBuf {
struct MsgBuf *next; /**< next msg in global queue */
struct MsgBuf **prev_p; /**< what points to us in linked list */
struct MsgBuf *real; /**< the actual MsgBuf we're attaching */
unsigned int ref; /**< reference count */
unsigned int length; /**< length of message */
unsigned int power; /**< size of buffer (power of 2) */
char msg[1]; /**< the message */
};
/** Return allocated length of the buffer of \a buf. */
#define bufsize(buf) (1 << (buf)->power)
/** Message body for a particular destination. */
struct Msg {
struct Msg *next; /**< next msg */
unsigned int sent; /**< bytes in msg that have already been sent */
struct MsgBuf *msg; /**< actual message in queue */
};
/** Statistics tracking for message sizes. */
struct MsgSizes {
unsigned int msgs; /**< total number of messages */
unsigned int sizes[BUFSIZE]; /**< histogram of message sizes */
};
/** Global tracking data for message buffers. */
static struct {
struct MsgBuf *msglist; /**< list of in-use MsgBuf's */
struct {
unsigned int alloc; /**< number of Msg's allocated */
unsigned int used; /**< number of Msg's in use */
struct Msg *free; /**< freelist of Msg's */
} msgs; /**< tracking info for Msg structs */
size_t tot_bufsize; /**< total amount of memory in buffers */
/** Array of MsgBuf information, one entry for each used bucket size. */
struct {
unsigned int alloc; /**< total MsgBuf's of this size */
unsigned int used; /**< number of MsgBuf's of this size in use */
struct MsgBuf *free; /**< list of free MsgBuf's */
} msgBufs[MB_MAX_SHIFT - MB_BASE_SHIFT + 1];
struct MsgSizes sizes; /**< histogram of message sizes */
} MQData;
/*
* This routine is used to remove a certain amount of data from a given
* queue and release the Msg (and MsgBuf) structure if needed
*/
/** Remove some data from a list within a message queue.
* @param[in,out] mq Message queue to remove from.
* @param[in,out] qlist Particular list within queue to remove from.
* @param[in,out] length_p Number of bytes left to remove.
*/
static void
msgq_delmsg(struct MsgQ *mq, struct MsgQList *qlist, unsigned int *length_p)
{
struct Msg *m;
unsigned int msglen;
assert(0 != mq);
assert(0 != qlist);
assert(0 != qlist->head);
assert(0 != length_p);
m = qlist->head; /* find the msg we're deleting from */
msglen = m->msg->length - m->sent; /* calculate how much is left */
if (*length_p >= msglen) { /* deleted it all? */
mq->length -= msglen; /* decrement length */
mq->count--; /* decrement the message count */
*length_p -= msglen;
msgq_clean(m->msg); /* free up the struct MsgBuf */
m->msg = 0; /* don't let it point anywhere nasty, please */
if (qlist->head == qlist->tail) /* figure out if we emptied the queue */
qlist->head = qlist->tail = 0;
else
qlist->head = m->next; /* just shift the list down some */
MQData.msgs.used--; /* struct Msg is not in use anymore */
m->next = MQData.msgs.free; /* throw it onto the free list */
MQData.msgs.free = m;
} else {
mq->length -= *length_p; /* decrement queue length */
m->sent += *length_p; /* this much of the message has been sent */
*length_p = 0; /* we've dealt with it all */
}
}
/** Initialize \a mq.
* @param[in] mq MsgQ to initialize.
*/
void
msgq_init(struct MsgQ *mq)
{
assert(0 != mq);
mq->length = 0;
mq->count = 0;
mq->queue.head = 0;
mq->queue.tail = 0;
mq->prio.head = 0;
mq->prio.tail = 0;
}
/** Delete bytes from the front of a message queue.
* @param[in] mq Queue to drop data from.
* @param[in] length Number of bytes to drop.
*/
void
msgq_delete(struct MsgQ *mq, unsigned int length)
{
assert(0 != mq);
while (length > 0) {
if (mq->queue.head && mq->queue.head->sent > 0) /* partial msg on norm q */
msgq_delmsg(mq, &mq->queue, &length);
else if (mq->prio.head) /* message (partial or complete) on prio queue */
msgq_delmsg(mq, &mq->prio, &length);
else if (mq->queue.head) /* message on normal queue */
msgq_delmsg(mq, &mq->queue, &length);
else
break;
}
}
/** Map data from a message queue to an I/O vector.
* @param[in] mq Message queue to send from.
* @param[out] iov Output vector.
* @param[in] count Number of elements in \a iov.
* @param[out] len Number of bytes mapped from \a mq to \a iov.
* @return Number of elements filled in \a iov.
*/
int
msgq_mapiov(const struct MsgQ *mq, struct iovec *iov, int count,
unsigned int *len)
{
struct Msg *queue;
struct Msg *prio;
int i = 0;
assert(0 != mq);
assert(0 != iov);
assert(0 != count);
assert(0 != len);
if (mq->length <= 0) /* no data to map */
return 0;
if (mq->queue.head && mq->queue.head->sent > 0) { /* partial msg on norm q */
iov[i].iov_base = mq->queue.head->msg->msg + mq->queue.head->sent;
iov[i].iov_len = mq->queue.head->msg->length - mq->queue.head->sent;
*len += iov[i].iov_len;
queue = mq->queue.head->next; /* where we start later... */
i++; /* filled an iovec... */
if (!--count) /* check for space */
return i;
} else
queue = mq->queue.head; /* start at head of queue */
if (mq->prio.head && mq->prio.head->sent > 0) { /* partial msg on prio q */
iov[i].iov_base = mq->prio.head->msg->msg + mq->prio.head->sent;
iov[i].iov_len = mq->prio.head->msg->length - mq->prio.head->sent;
*len += iov[i].iov_len;
prio = mq->prio.head->next; /* where we start later... */
i++; /* filled an iovec... */
if (!--count) /* check for space */
return i;
} else
prio = mq->prio.head; /* start at head of prio */
for (; prio; prio = prio->next) { /* go through prio queue */
iov[i].iov_base = prio->msg->msg; /* store message */
iov[i].iov_len = prio->msg->length;
*len += iov[i].iov_len;
i++; /* filled an iovec... */
if (!--count) /* check for space */
return i;
}
for (; queue; queue = queue->next) { /* go through normal queue */
iov[i].iov_base = queue->msg->msg;
iov[i].iov_len = queue->msg->length;
*len += iov[i].iov_len;
i++; /* filled an iovec... */
if (!--count) /* check for space */
return i;
}
return i;
}
/** Allocate a message buffer large enough to hold \a length bytes.
* TODO: \a in_mb needs better documentation.
* @param[in] in_mb Some other message buffer(?).
* @param[in] length Number of bytes of space to reserve in output.
* @return Pointer to some usable message buffer.
*/
static struct MsgBuf *
msgq_alloc(struct MsgBuf *in_mb, int length)
{
struct MsgBuf *mb;
int power;
/* Find the power of two size that will accommodate the message */
for (power = MB_BASE_SHIFT; power < MB_MAX_SHIFT + 1; power++)
if ((length - 1) >> power == 0)
break;
assert((1 << power) >= length);
assert((1 << power) <= 512);
length = 1 << power; /* reset the length */
/* If the message needs a buffer of exactly the existing size, just use it */
if (in_mb && in_mb->power == power) {
in_mb->real = in_mb; /* real buffer is this buffer */
return in_mb;
}
/* Try popping one off the freelist first */
if ((mb = MQData.msgBufs[power - MB_BASE_SHIFT].free)) {
MQData.msgBufs[power - MB_BASE_SHIFT].free = mb->next;
} else if (MQData.tot_bufsize < feature_int(FEAT_BUFFERPOOL)) {
/* Allocate another if we won't bust the BUFFERPOOL */
Debug((DEBUG_MALLOC, "Allocating MsgBuf of length %d (total size %zu)",
length, sizeof(struct MsgBuf) + length));
mb = (struct MsgBuf *)MyMalloc(sizeof(struct MsgBuf) + length);
MQData.msgBufs[power - MB_BASE_SHIFT].alloc++;
mb->power = power; /* remember size */
MQData.tot_bufsize += length;
}
if (mb) {
MQData.msgBufs[power - MB_BASE_SHIFT].used++; /* how many are we using? */
mb->real = 0; /* essential initializations */
mb->ref = 1;
if (in_mb) /* remember who's the *real* buffer */
in_mb->real = mb;
} else if (in_mb) /* just use the input buffer */
mb = in_mb->real = in_mb;
return mb; /* return the buffer */
}
/** Deallocate unused message buffers.
*/
static void
msgq_clear_freembs(void)
{
struct MsgBuf *mb;
int i;
/* Walk through the various size classes */
for (i = MB_BASE_SHIFT; i < MB_MAX_SHIFT + 1; i++)
/* walk down the free list */
while ((mb = MQData.msgBufs[i - MB_BASE_SHIFT].free)) {
MQData.msgBufs[i - MB_BASE_SHIFT].free = mb->next; /* shift free list */
MQData.msgBufs[i - MB_BASE_SHIFT].alloc--; /* reduce allocation count */
MQData.tot_bufsize -= 1 << i; /* reduce total buffer allocation count */
MyFree(mb); /* and free the buffer */
}
}
/** Format a message buffer for a client from a format string.
* @param[in] dest %Client that receives the data (may be NULL).
* @param[in] format Format string for message.
* @param[in] vl Argument list for \a format.
* @return Allocated MsgBuf.
*/
struct MsgBuf *
msgq_vmake(struct Client *dest, const char *format, va_list vl)
{
struct MsgBuf *mb;
assert(0 != format);
if (!(mb = msgq_alloc(0, BUFSIZE))) {
if (feature_bool(FEAT_HAS_FERGUSON_FLUSHER)) {
/*
* from "Married With Children" episode were Al bought a REAL toilet
* on the black market because he was tired of the wimpy water
* conserving toilets they make these days --Bleep
*/
/*
* Apparently this doesn't work, the server _has_ to
* dump a few clients to handle the load. A fully loaded
* server cannot handle a net break without dumping some
* clients. If we flush the connections here under a full
* load we may end up starving the kernel for mbufs and
* crash the machine
*/
/*
* attempt to recover from buffer starvation before
* bailing this may help servers running out of memory
*/
flush_connections(0);
mb = msgq_alloc(0, BUFSIZE);
}
if (!mb) { /* OK, try clearing the buffer free list */
msgq_clear_freembs();
mb = msgq_alloc(0, BUFSIZE);
}
if (!mb) { /* OK, try killing a client */
kill_highest_sendq(0); /* Don't kill any server connections */
msgq_clear_freembs(); /* Release whatever was just freelisted */
mb = msgq_alloc(0, BUFSIZE);
}
if (!mb) { /* hmmm... */
kill_highest_sendq(1); /* Try killing a server connection now */
msgq_clear_freembs(); /* Clear freelist again */
mb = msgq_alloc(0, BUFSIZE);
}
if (!mb) /* AIEEEE! */
server_panic("Unable to allocate buffers!");
}
mb->next = MQData.msglist; /* initialize the msgbuf */
mb->prev_p = &MQData.msglist;
/* fill the buffer */
mb->length = ircd_vsnprintf(dest, mb->msg, bufsize(mb) - 1, format, vl);
if (mb->length > bufsize(mb) - 2)
mb->length = bufsize(mb) - 2;
mb->msg[mb->length++] = '\r'; /* add \r\n to buffer */
mb->msg[mb->length++] = '\n';
mb->msg[mb->length] = '\0'; /* not strictly necessary */
assert(mb->length <= bufsize(mb));
if (MQData.msglist) /* link it into the list */
MQData.msglist->prev_p = &mb->next;
MQData.msglist = mb;
return mb;
}
/** Format a message buffer for a client from a format string.
* @param[in] dest %Client that receives the data (may be NULL).
* @param[in] format Format string for message.
* @return Allocated MsgBuf.
*/
struct MsgBuf *
msgq_make(struct Client *dest, const char *format, ...)
{
va_list vl;
struct MsgBuf *mb;
va_start(vl, format);
mb = msgq_vmake(dest, format, vl);
va_end(vl);
return mb;
}
/** Append text to an existing message buffer.
* @param[in] dest %Client for whom to format the message.
* @param[in] mb Message buffer to append to.
* @param[in] format Format string of what to append.
*/
void
msgq_append(struct Client *dest, struct MsgBuf *mb, const char *format, ...)
{
va_list vl;
assert(0 != mb);
assert(0 != format);
assert(0 == mb->real);
assert(2 < mb->length);
assert(bufsize(mb) >= mb->length);
mb->length -= 2; /* back up to before \r\n */
va_start(vl, format); /* append to the buffer */
mb->length += ircd_vsnprintf(dest, mb->msg + mb->length,
bufsize(mb) - mb->length - 1, format, vl);
va_end(vl);
if (mb->length > bufsize(mb) - 2)
mb->length = bufsize(mb) - 2;
mb->msg[mb->length++] = '\r'; /* add \r\n to buffer */
mb->msg[mb->length++] = '\n';
mb->msg[mb->length] = '\0'; /* not strictly necessary */
assert(mb->length <= bufsize(mb));
}
/** Decrement the reference count on \a mb, freeing it if needed.
* @param[in] mb MsgBuf to release.
*/
void
msgq_clean(struct MsgBuf *mb)
{
assert(0 != mb);
assert(0 < mb->ref);
if (!--mb->ref) { /* deallocate the message */
if (mb->prev_p) {
*mb->prev_p = mb->next; /* clip it out of active MsgBuf's list */
if (mb->next)
mb->next->prev_p = mb->prev_p;
}
if (mb->real && mb->real != mb) /* clean up the real buffer */
msgq_clean(mb->real);
mb->next = MQData.msgBufs[mb->power - MB_BASE_SHIFT].free;
MQData.msgBufs[mb->power - MB_BASE_SHIFT].free = mb;
MQData.msgBufs[mb->power - MB_BASE_SHIFT].used--;
mb->prev_p = 0;
}
}
/** Append a message to a peer's message queue.
* @param[in] mq Message queue to append to.
* @param[in] mb Message to append.
* @param[in] prio If non-zero, use the high-priority (lag-busting) message list; else use the normal list.
*/
void
msgq_add(struct MsgQ *mq, struct MsgBuf *mb, int prio)
{
struct MsgQList *qlist;
struct Msg *msg;
assert(0 != mq);
assert(0 != mb);
assert(0 < mb->ref);
assert(0 < mb->length);
/* Priority queue breaks SSL. Does nothing at all iv ever noticed to make any improvements
* to irc. so i'm just flatly breaking it here. -Rubin
*/
prio = 0;
Debug((DEBUG_SEND, "Adding buffer %p [%.*s] length %u to %s queue", mb,
mb->length - 2, mb->msg, mb->length, prio ? "priority" : "normal"));
qlist = prio ? &mq->prio : &mq->queue;
if (!(msg = MQData.msgs.free)) { /* do I need to allocate one? */
msg = (struct Msg *)MyMalloc(sizeof(struct Msg));
MQData.msgs.alloc++; /* we allocated another */
} else /* shift the free list */
MQData.msgs.free = MQData.msgs.free->next;
MQData.msgs.used++; /* we're using another */
msg->next = 0; /* initialize the msg */
msg->sent = 0;
/* Get the real buffer, allocating one if necessary */
if (!mb->real) {
struct MsgBuf *tmp;
MQData.sizes.msgs++; /* update histogram counts */
MQData.sizes.sizes[mb->length - 1]++;
tmp = msgq_alloc(mb, mb->length); /* allocate a close-fitting buffer */
if (tmp != mb) { /* OK, prepare the new "real" buffer */
Debug((DEBUG_SEND, "Copying old buffer %p [%.*s] length %u into new "
"buffer %p size %u", mb, mb->length - 2, mb->msg, mb->length,
tmp, bufsize(tmp)));
memcpy(tmp->msg, mb->msg, mb->length + 1); /* copy string over */
tmp->length = mb->length;
tmp->next = mb->next; /* replace it in the list, now */
if (tmp->next)
tmp->next->prev_p = &tmp->next;
tmp->prev_p = mb->prev_p;
*tmp->prev_p = tmp;
mb->next = 0; /* this one's no longer in the list */
mb->prev_p = 0;
}
}
mb = mb->real; /* work with the real buffer */
mb->ref++; /* increment the ref count on the buffer */
msg->msg = mb; /* point at the real message buffer now */
if (!qlist->head) /* queue list was empty; head and tail point to msg */
qlist->head = qlist->tail = msg;
else {
assert(0 != qlist->tail);
qlist->tail->next = msg; /* queue had something in it; add to end */
qlist->tail = msg;
}
mq->length += mb->length; /* update the queue length */
mq->count++; /* and the queue count */
}
/** Report memory statistics for message buffers.
* @param[in] cptr Client requesting information.
* @param[out] msg_alloc Receives number of bytes allocated in Msg structs.
* @param[out] msgbuf_alloc Receives number of bytes allocated in MsgBuf structs.
*/
void
msgq_count_memory(struct Client *cptr, size_t *msg_alloc, size_t *msgbuf_alloc)
{
int i;
size_t total = 0, size;
assert(0 != cptr);
assert(0 != msg_alloc);
assert(0 != msgbuf_alloc);
/* Data for Msg's is simple, so just send it */
send_reply(cptr, SND_EXPLICIT | RPL_STATSDEBUG,
":Msgs allocated %d(%zu) used %d(%zu) text %zu",
MQData.msgs.alloc, MQData.msgs.alloc * sizeof(struct Msg),
MQData.msgs.used, MQData.msgs.used * sizeof(struct Msg),
MQData.tot_bufsize);
/* count_memory() wants to know the total */
*msg_alloc = MQData.msgs.alloc * sizeof(struct Msg);
/* Ok, now walk through each size class */
for (i = MB_BASE_SHIFT; i < MB_MAX_SHIFT + 1; i++) {
size = sizeof(struct MsgBuf) + (1 << i); /* total size of a buffer */
/* Send information for this buffer size class */
send_reply(cptr, SND_EXPLICIT | RPL_STATSDEBUG,
":MsgBufs of size %zu allocated %d(%zu) used %d(%zu)", 1 << i,
MQData.msgBufs[i - MB_BASE_SHIFT].alloc,
MQData.msgBufs[i - MB_BASE_SHIFT].alloc * size,
MQData.msgBufs[i - MB_BASE_SHIFT].used,
MQData.msgBufs[i - MB_BASE_SHIFT].used * size);
/* count_memory() wants to know the total */
total += MQData.msgBufs[i - MB_BASE_SHIFT].alloc * size;
}
*msgbuf_alloc = total;
}
/** Report remaining space in a MsgBuf.
* @param[in] mb Message buffer to check.
* @return Number of additional bytes that can be appended to the message.
*/
unsigned int
msgq_bufleft(struct MsgBuf *mb)
{
assert(0 != mb);
return bufsize(mb) - mb->length; /* \r\n counted in mb->length */
}
/** Send histogram of message lengths to a client.
* @param[in] cptr Client requesting statistics.
* @param[in] sd Stats descriptor for request (ignored).
* @param[in] param Extra parameter from user (ignored).
*/
void
msgq_histogram(struct Client *cptr, const struct StatDesc *sd, char *param)
{
struct MsgSizes tmp = MQData.sizes; /* All hail structure copy! */
int i;
send_reply(cptr, SND_EXPLICIT | RPL_STATSDEBUG,
":Histogram of message lengths (%lu messages)", tmp.msgs);
for (i = 0; i + 16 <= BUFSIZE; i += 16)
send_reply(cptr, SND_EXPLICIT | RPL_STATSDEBUG, ":% 4d: %u %u %u %u "
"%u %u %u %u %u %u %u %u %u %u %u %u", i + 1,
tmp.sizes[i + 0], tmp.sizes[i + 1], tmp.sizes[i + 2],
tmp.sizes[i + 3], tmp.sizes[i + 4], tmp.sizes[i + 5],
tmp.sizes[i + 6], tmp.sizes[i + 7], tmp.sizes[i + 8],
tmp.sizes[i + 9], tmp.sizes[i + 10], tmp.sizes[i + 11],
tmp.sizes[i + 12], tmp.sizes[i + 13], tmp.sizes[i + 14],
tmp.sizes[i + 15]);
}
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