#include <machine/rtems-bsd-config.h>
/*
* Copyright (c) 2010 Riccardo Panicucci, Universita` di Pisa
* Copyright (c) 2000-2002 Luigi Rizzo, Universita` di Pisa
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* $FreeBSD$
*/
#ifdef _KERNEL
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <net/if.h> /* IFNAMSIZ */
#include <netinet/in.h>
#include <netinet/ip_var.h> /* ipfw_rule_ref */
#include <netinet/ip_fw.h> /* flow_id */
#include <netinet/ip_dummynet.h>
#include <netinet/ipfw/dn_heap.h>
#include <netinet/ipfw/ip_dn_private.h>
#include <netinet/ipfw/dn_sched.h>
#else
#include <dn_test.h>
#endif
#ifndef MAX64
#define MAX64(x,y) (( (int64_t) ( (y)-(x) )) > 0 ) ? (y) : (x)
#endif
/*
* timestamps are computed on 64 bit using fixed point arithmetic.
* LMAX_BITS, WMAX_BITS are the max number of bits for the packet len
* and sum of weights, respectively. FRAC_BITS is the number of
* fractional bits. We want FRAC_BITS >> WMAX_BITS to avoid too large
* errors when computing the inverse, FRAC_BITS < 32 so we can do 1/w
* using an unsigned 32-bit division, and to avoid wraparounds we need
* LMAX_BITS + WMAX_BITS + FRAC_BITS << 64
* As an example
* FRAC_BITS = 26, LMAX_BITS=14, WMAX_BITS = 19
*/
#ifndef FRAC_BITS
#define FRAC_BITS 28 /* shift for fixed point arithmetic */
#define ONE_FP (1UL << FRAC_BITS)
#endif
/*
* Private information for the scheduler instance:
* sch_heap (key is Finish time) returns the next queue to serve
* ne_heap (key is Start time) stores not-eligible queues
* idle_heap (key=start/finish time) stores idle flows. It must
* support extract-from-middle.
* A flow is only in 1 of the three heaps.
* XXX todo: use a more efficient data structure, e.g. a tree sorted
* by F with min_subtree(S) in each node
*/
struct wf2qp_si {
struct dn_heap sch_heap; /* top extract - key Finish time */
struct dn_heap ne_heap; /* top extract - key Start time */
struct dn_heap idle_heap; /* random extract - key Start=Finish time */
uint64_t V; /* virtual time */
uint32_t inv_wsum; /* inverse of sum of weights */
uint32_t wsum; /* sum of weights */
};
struct wf2qp_queue {
struct dn_queue _q;
uint64_t S, F; /* start time, finish time */
uint32_t inv_w; /* ONE_FP / weight */
int32_t heap_pos; /* position (index) of struct in heap */
};
/*
* This file implements a WF2Q+ scheduler as it has been in dummynet
* since 2000.
* The scheduler supports per-flow queues and has O(log N) complexity.
*
* WF2Q+ needs to drain entries from the idle heap so that we
* can keep the sum of weights up to date. We can do it whenever
* we get a chance, or periodically, or following some other
* strategy. The function idle_check() drains at most N elements
* from the idle heap.
*/
static void
idle_check(struct wf2qp_si *si, int n, int force)
{
struct dn_heap *h = &si->idle_heap;
while (n-- > 0 && h->elements > 0 &&
(force || DN_KEY_LT(HEAP_TOP(h)->key, si->V))) {
struct dn_queue *q = HEAP_TOP(h)->object;
struct wf2qp_queue *alg_fq = (struct wf2qp_queue *)q;
heap_extract(h, NULL);
/* XXX to let the flowset delete the queue we should
* mark it as 'unused' by the scheduler.
*/
alg_fq->S = alg_fq->F + 1; /* Mark timestamp as invalid. */
si->wsum -= q->fs->fs.par[0]; /* adjust sum of weights */
if (si->wsum > 0)
si->inv_wsum = ONE_FP/si->wsum;
}
}
static int
wf2qp_enqueue(struct dn_sch_inst *_si, struct dn_queue *q, struct mbuf *m)
{
struct dn_fsk *fs = q->fs;
struct wf2qp_si *si = (struct wf2qp_si *)(_si + 1);
struct wf2qp_queue *alg_fq;
uint64_t len = m->m_pkthdr.len;
if (m != q->mq.head) {
if (dn_enqueue(q, m, 0)) /* packet was dropped */
return 1;
if (m != q->mq.head) /* queue was already busy */
return 0;
}
/* If reach this point, queue q was idle */
alg_fq = (struct wf2qp_queue *)q;
if (DN_KEY_LT(alg_fq->F, alg_fq->S)) {
/* F<S means timestamps are invalid ->brand new queue. */
alg_fq->S = si->V; /* init start time */
si->wsum += fs->fs.par[0]; /* add weight of new queue. */
si->inv_wsum = ONE_FP/si->wsum;
} else { /* if it was idle then it was in the idle heap */
heap_extract(&si->idle_heap, q);
alg_fq->S = MAX64(alg_fq->F, si->V); /* compute new S */
}
alg_fq->F = alg_fq->S + len * alg_fq->inv_w;
/* if nothing is backlogged, make sure this flow is eligible */
if (si->ne_heap.elements == 0 && si->sch_heap.elements == 0)
si->V = MAX64(alg_fq->S, si->V);
/*
* Look at eligibility. A flow is not eligibile if S>V (when
* this happens, it means that there is some other flow already
* scheduled for the same pipe, so the sch_heap cannot be
* empty). If the flow is not eligible we just store it in the
* ne_heap. Otherwise, we store in the sch_heap.
* Note that for all flows in sch_heap (SCH), S_i <= V,
* and for all flows in ne_heap (NEH), S_i > V.
* So when we need to compute max(V, min(S_i)) forall i in
* SCH+NEH, we only need to look into NEH.
*/
if (DN_KEY_LT(si->V, alg_fq->S)) {
/* S>V means flow Not eligible. */
if (si->sch_heap.elements == 0)
D("++ ouch! not eligible but empty scheduler!");
heap_insert(&si->ne_heap, alg_fq->S, q);
} else {
heap_insert(&si->sch_heap, alg_fq->F, q);
}
return 0;
}
/* XXX invariant: sch > 0 || V >= min(S in neh) */
static struct mbuf *
wf2qp_dequeue(struct dn_sch_inst *_si)
{
/* Access scheduler instance private data */
struct wf2qp_si *si = (struct wf2qp_si *)(_si + 1);
struct mbuf *m;
struct dn_queue *q;
struct dn_heap *sch = &si->sch_heap;
struct dn_heap *neh = &si->ne_heap;
struct wf2qp_queue *alg_fq;
if (sch->elements == 0 && neh->elements == 0) {
/* we have nothing to do. We could kill the idle heap
* altogether and reset V
*/
idle_check(si, 0x7fffffff, 1);
si->V = 0;
si->wsum = 0; /* should be set already */
return NULL; /* quick return if nothing to do */
}
idle_check(si, 1, 0); /* drain something from the idle heap */
/* make sure at least one element is eligible, bumping V
* and moving entries that have become eligible.
* We need to repeat the first part twice, before and
* after extracting the candidate, or enqueue() will
* find the data structure in a wrong state.
*/
m = NULL;
for(;;) {
/*
* Compute V = max(V, min(S_i)). Remember that all elements
* in sch have by definition S_i <= V so if sch is not empty,
* V is surely the max and we must not update it. Conversely,
* if sch is empty we only need to look at neh.
* We don't need to move the queues, as it will be done at the
* next enqueue
*/
if (sch->elements == 0 && neh->elements > 0) {
si->V = MAX64(si->V, HEAP_TOP(neh)->key);
}
while (neh->elements > 0 &&
DN_KEY_LEQ(HEAP_TOP(neh)->key, si->V)) {
q = HEAP_TOP(neh)->object;
alg_fq = (struct wf2qp_queue *)q;
heap_extract(neh, NULL);
heap_insert(sch, alg_fq->F, q);
}
if (m) /* pkt found in previous iteration */
break;
/* ok we have at least one eligible pkt */
q = HEAP_TOP(sch)->object;
alg_fq = (struct wf2qp_queue *)q;
m = dn_dequeue(q);
heap_extract(sch, NULL); /* Remove queue from heap. */
si->V += (uint64_t)(m->m_pkthdr.len) * si->inv_wsum;
alg_fq->S = alg_fq->F; /* Update start time. */
if (q->mq.head == 0) { /* not backlogged any more. */
heap_insert(&si->idle_heap, alg_fq->F, q);
} else { /* Still backlogged. */
/* Update F, store in neh or sch */
uint64_t len = q->mq.head->m_pkthdr.len;
alg_fq->F += len * alg_fq->inv_w;
if (DN_KEY_LEQ(alg_fq->S, si->V)) {
heap_insert(sch, alg_fq->F, q);
} else {
heap_insert(neh, alg_fq->S, q);
}
}
}
return m;
}
static int
wf2qp_new_sched(struct dn_sch_inst *_si)
{
struct wf2qp_si *si = (struct wf2qp_si *)(_si + 1);
int ofs = offsetof(struct wf2qp_queue, heap_pos);
/* all heaps support extract from middle */
if (heap_init(&si->idle_heap, 16, ofs) ||
heap_init(&si->sch_heap, 16, ofs) ||
heap_init(&si->ne_heap, 16, ofs)) {
heap_free(&si->ne_heap);
heap_free(&si->sch_heap);
heap_free(&si->idle_heap);
return ENOMEM;
}
return 0;
}
static int
wf2qp_free_sched(struct dn_sch_inst *_si)
{
struct wf2qp_si *si = (struct wf2qp_si *)(_si + 1);
heap_free(&si->sch_heap);
heap_free(&si->ne_heap);
heap_free(&si->idle_heap);
return 0;
}
static int
wf2qp_new_fsk(struct dn_fsk *fs)
{
ipdn_bound_var(&fs->fs.par[0], 1,
1, 100, "WF2Q+ weight");
return 0;
}
static int
wf2qp_new_queue(struct dn_queue *_q)
{
struct wf2qp_queue *q = (struct wf2qp_queue *)_q;
_q->ni.oid.subtype = DN_SCHED_WF2QP;
q->F = 0; /* not strictly necessary */
q->S = q->F + 1; /* mark timestamp as invalid. */
q->inv_w = ONE_FP / _q->fs->fs.par[0];
if (_q->mq.head != NULL) {
wf2qp_enqueue(_q->_si, _q, _q->mq.head);
}
return 0;
}
/*
* Called when the infrastructure removes a queue (e.g. flowset
* is reconfigured). Nothing to do if we did not 'own' the queue,
* otherwise remove it from the right heap and adjust the sum
* of weights.
*/
static int
wf2qp_free_queue(struct dn_queue *q)
{
struct wf2qp_queue *alg_fq = (struct wf2qp_queue *)q;
struct wf2qp_si *si = (struct wf2qp_si *)(q->_si + 1);
if (alg_fq->S >= alg_fq->F + 1)
return 0; /* nothing to do, not in any heap */
si->wsum -= q->fs->fs.par[0];
if (si->wsum > 0)
si->inv_wsum = ONE_FP/si->wsum;
/* extract from the heap. XXX TODO we may need to adjust V
* to make sure the invariants hold.
*/
if (q->mq.head == NULL) {
heap_extract(&si->idle_heap, q);
} else if (DN_KEY_LT(si->V, alg_fq->S)) {
heap_extract(&si->ne_heap, q);
} else {
heap_extract(&si->sch_heap, q);
}
return 0;
}
/*
* WF2Q+ scheduler descriptor
* contains the type of the scheduler, the name, the size of the
* structures and function pointers.
*/
static struct dn_alg wf2qp_desc = {
_SI( .type = ) DN_SCHED_WF2QP,
_SI( .name = ) "WF2Q+",
_SI( .flags = ) DN_MULTIQUEUE,
/* we need extra space in the si and the queue */
_SI( .schk_datalen = ) 0,
_SI( .si_datalen = ) sizeof(struct wf2qp_si),
_SI( .q_datalen = ) sizeof(struct wf2qp_queue) -
sizeof(struct dn_queue),
_SI( .enqueue = ) wf2qp_enqueue,
_SI( .dequeue = ) wf2qp_dequeue,
_SI( .config = ) NULL,
_SI( .destroy = ) NULL,
_SI( .new_sched = ) wf2qp_new_sched,
_SI( .free_sched = ) wf2qp_free_sched,
_SI( .new_fsk = ) wf2qp_new_fsk,
_SI( .free_fsk = ) NULL,
_SI( .new_queue = ) wf2qp_new_queue,
_SI( .free_queue = ) wf2qp_free_queue,
};
DECLARE_DNSCHED_MODULE(dn_wf2qp, &wf2qp_desc);
