/*- * Copyright (c) 1991-1997 Regents of the University of California. * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the Network Research * Group at Lawrence Berkeley Laboratory. * 4. Neither the name of the University nor of the Laboratory may be used * to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * LBL code modified by speer@eng.sun.com, May 1977. * For questions and/or comments, please send mail to cbq@ee.lbl.gov * * @(#)rm_class.c 1.48 97/12/05 SMI * $KAME: altq_rmclass.c,v 1.19 2005/04/13 03:44:25 suz Exp $ * $FreeBSD$ */ #include "opt_altq.h" #include "opt_inet.h" #include "opt_inet6.h" #ifdef ALTQ_CBQ /* cbq is enabled by ALTQ_CBQ option in opt_altq.h */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Local Macros */ #define reset_cutoff(ifd) { ifd->cutoff_ = RM_MAXDEPTH; } /* * Local routines. */ static int rmc_satisfied(struct rm_class *, struct timeval *); static void rmc_wrr_set_weights(struct rm_ifdat *); static void rmc_depth_compute(struct rm_class *); static void rmc_depth_recompute(rm_class_t *); static mbuf_t *_rmc_wrr_dequeue_next(struct rm_ifdat *, int); static mbuf_t *_rmc_prr_dequeue_next(struct rm_ifdat *, int); static int _rmc_addq(rm_class_t *, mbuf_t *); static void _rmc_dropq(rm_class_t *); static mbuf_t *_rmc_getq(rm_class_t *); static mbuf_t *_rmc_pollq(rm_class_t *); static int rmc_under_limit(struct rm_class *, struct timeval *); static void rmc_tl_satisfied(struct rm_ifdat *, struct timeval *); static void rmc_drop_action(struct rm_class *); static void rmc_restart(void *); static void rmc_root_overlimit(struct rm_class *, struct rm_class *); #define BORROW_OFFTIME /* * BORROW_OFFTIME (experimental): * borrow the offtime of the class borrowing from. * the reason is that when its own offtime is set, the class is unable * to borrow much, especially when cutoff is taking effect. * but when the borrowed class is overloaded (advidle is close to minidle), * use the borrowing class's offtime to avoid overload. */ #define ADJUST_CUTOFF /* * ADJUST_CUTOFF (experimental): * if no underlimit class is found due to cutoff, increase cutoff and * retry the scheduling loop. * also, don't invoke delay_actions while cutoff is taking effect, * since a sleeping class won't have a chance to be scheduled in the * next loop. * * now heuristics for setting the top-level variable (cutoff_) becomes: * 1. if a packet arrives for a not-overlimit class, set cutoff * to the depth of the class. * 2. if cutoff is i, and a packet arrives for an overlimit class * with an underlimit ancestor at a lower level than i (say j), * then set cutoff to j. * 3. at scheduling a packet, if there is no underlimit class * due to the current cutoff level, increase cutoff by 1 and * then try to schedule again. */ /* * rm_class_t * * rmc_newclass(...) - Create a new resource management class at priority * 'pri' on the interface given by 'ifd'. * * nsecPerByte is the data rate of the interface in nanoseconds/byte. * E.g., 800 for a 10Mb/s ethernet. If the class gets less * than 100% of the bandwidth, this number should be the * 'effective' rate for the class. Let f be the * bandwidth fraction allocated to this class, and let * nsPerByte be the data rate of the output link in * nanoseconds/byte. Then nsecPerByte is set to * nsPerByte / f. E.g., 1600 (= 800 / .5) * for a class that gets 50% of an ethernet's bandwidth. * * action the routine to call when the class is over limit. * * maxq max allowable queue size for class (in packets). * * parent parent class pointer. * * borrow class to borrow from (should be either 'parent' or null). * * maxidle max value allowed for class 'idle' time estimate (this * parameter determines how large an initial burst of packets * can be before overlimit action is invoked. * * offtime how long 'delay' action will delay when class goes over * limit (this parameter determines the steady-state burst * size when a class is running over its limit). * * Maxidle and offtime have to be computed from the following: If the * average packet size is s, the bandwidth fraction allocated to this * class is f, we want to allow b packet bursts, and the gain of the * averaging filter is g (= 1 - 2^(-RM_FILTER_GAIN)), then: * * ptime = s * nsPerByte * (1 - f) / f * maxidle = ptime * (1 - g^b) / g^b * minidle = -ptime * (1 / (f - 1)) * offtime = ptime * (1 + 1/(1 - g) * (1 - g^(b - 1)) / g^(b - 1) * * Operationally, it's convenient to specify maxidle & offtime in units * independent of the link bandwidth so the maxidle & offtime passed to * this routine are the above values multiplied by 8*f/(1000*nsPerByte). * (The constant factor is a scale factor needed to make the parameters * integers. This scaling also means that the 'unscaled' values of * maxidle*nsecPerByte/8 and offtime*nsecPerByte/8 will be in microseconds, * not nanoseconds.) Also note that the 'idle' filter computation keeps * an estimate scaled upward by 2^RM_FILTER_GAIN so the passed value of * maxidle also must be scaled upward by this value. Thus, the passed * values for maxidle and offtime can be computed as follows: * * maxidle = maxidle * 2^RM_FILTER_GAIN * 8 / (1000 * nsecPerByte) * offtime = offtime * 8 / (1000 * nsecPerByte) * * When USE_HRTIME is employed, then maxidle and offtime become: * maxidle = maxilde * (8.0 / nsecPerByte); * offtime = offtime * (8.0 / nsecPerByte); */ struct rm_class * rmc_newclass(int pri, struct rm_ifdat *ifd, u_int nsecPerByte, void (*action)(rm_class_t *, rm_class_t *), int maxq, struct rm_class *parent, struct rm_class *borrow, u_int maxidle, int minidle, u_int offtime, int pktsize, int flags) { struct rm_class *cl; struct rm_class *peer; int s; if (pri >= RM_MAXPRIO) return (NULL); #ifndef ALTQ_RED if (flags & RMCF_RED) { #ifdef ALTQ_DEBUG printf("rmc_newclass: RED not configured for CBQ!\n"); #endif return (NULL); } #endif #ifndef ALTQ_RIO if (flags & RMCF_RIO) { #ifdef ALTQ_DEBUG printf("rmc_newclass: RIO not configured for CBQ!\n"); #endif return (NULL); } #endif #ifndef ALTQ_CODEL if (flags & RMCF_CODEL) { #ifdef ALTQ_DEBUG printf("rmc_newclass: CODEL not configured for CBQ!\n"); #endif return (NULL); } #endif cl = malloc(sizeof(struct rm_class), M_DEVBUF, M_NOWAIT | M_ZERO); if (cl == NULL) return (NULL); CALLOUT_INIT(&cl->callout_); cl->q_ = malloc(sizeof(class_queue_t), M_DEVBUF, M_NOWAIT | M_ZERO); if (cl->q_ == NULL) { free(cl, M_DEVBUF); return (NULL); } /* * Class initialization. */ cl->children_ = NULL; cl->parent_ = parent; cl->borrow_ = borrow; cl->leaf_ = 1; cl->ifdat_ = ifd; cl->pri_ = pri; cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */ cl->depth_ = 0; cl->qthresh_ = 0; cl->ns_per_byte_ = nsecPerByte; qlimit(cl->q_) = maxq; qtype(cl->q_) = Q_DROPHEAD; qlen(cl->q_) = 0; cl->flags_ = flags; #if 1 /* minidle is also scaled in ALTQ */ cl->minidle_ = (minidle * (int)nsecPerByte) / 8; if (cl->minidle_ > 0) cl->minidle_ = 0; #else cl->minidle_ = minidle; #endif cl->maxidle_ = (maxidle * nsecPerByte) / 8; if (cl->maxidle_ == 0) cl->maxidle_ = 1; #if 1 /* offtime is also scaled in ALTQ */ cl->avgidle_ = cl->maxidle_; cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN; if (cl->offtime_ == 0) cl->offtime_ = 1; #else cl->avgidle_ = 0; cl->offtime_ = (offtime * nsecPerByte) / 8; #endif cl->overlimit = action; #ifdef ALTQ_RED if (flags & (RMCF_RED|RMCF_RIO)) { int red_flags, red_pkttime; red_flags = 0; if (flags & RMCF_ECN) red_flags |= REDF_ECN; if (flags & RMCF_FLOWVALVE) red_flags |= REDF_FLOWVALVE; #ifdef ALTQ_RIO if (flags & RMCF_CLEARDSCP) red_flags |= RIOF_CLEARDSCP; #endif red_pkttime = nsecPerByte * pktsize / 1000; if (flags & RMCF_RED) { cl->red_ = red_alloc(0, 0, qlimit(cl->q_) * 10/100, qlimit(cl->q_) * 30/100, red_flags, red_pkttime); if (cl->red_ != NULL) qtype(cl->q_) = Q_RED; } #ifdef ALTQ_RIO else { cl->red_ = (red_t *)rio_alloc(0, NULL, red_flags, red_pkttime); if (cl->red_ != NULL) qtype(cl->q_) = Q_RIO; } #endif } #endif /* ALTQ_RED */ #ifdef ALTQ_CODEL if (flags & RMCF_CODEL) { cl->codel_ = codel_alloc(5, 100, 0); if (cl->codel_ != NULL) qtype(cl->q_) = Q_CODEL; } #endif /* * put the class into the class tree */ s = splnet(); IFQ_LOCK(ifd->ifq_); if ((peer = ifd->active_[pri]) != NULL) { /* find the last class at this pri */ cl->peer_ = peer; while (peer->peer_ != ifd->active_[pri]) peer = peer->peer_; peer->peer_ = cl; } else { ifd->active_[pri] = cl; cl->peer_ = cl; } if (cl->parent_) { cl->next_ = parent->children_; parent->children_ = cl; parent->leaf_ = 0; } /* * Compute the depth of this class and its ancestors in the class * hierarchy. */ rmc_depth_compute(cl); /* * If CBQ's WRR is enabled, then initialize the class WRR state. */ if (ifd->wrr_) { ifd->num_[pri]++; ifd->alloc_[pri] += cl->allotment_; rmc_wrr_set_weights(ifd); } IFQ_UNLOCK(ifd->ifq_); splx(s); return (cl); } int rmc_modclass(struct rm_class *cl, u_int nsecPerByte, int maxq, u_int maxidle, int minidle, u_int offtime, int pktsize) { struct rm_ifdat *ifd; u_int old_allotment; int s; ifd = cl->ifdat_; old_allotment = cl->allotment_; s = splnet(); IFQ_LOCK(ifd->ifq_); cl->allotment_ = RM_NS_PER_SEC / nsecPerByte; /* Bytes per sec */ cl->qthresh_ = 0; cl->ns_per_byte_ = nsecPerByte; qlimit(cl->q_) = maxq; #if 1 /* minidle is also scaled in ALTQ */ cl->minidle_ = (minidle * nsecPerByte) / 8; if (cl->minidle_ > 0) cl->minidle_ = 0; #else cl->minidle_ = minidle; #endif cl->maxidle_ = (maxidle * nsecPerByte) / 8; if (cl->maxidle_ == 0) cl->maxidle_ = 1; #if 1 /* offtime is also scaled in ALTQ */ cl->avgidle_ = cl->maxidle_; cl->offtime_ = ((offtime * nsecPerByte) / 8) >> RM_FILTER_GAIN; if (cl->offtime_ == 0) cl->offtime_ = 1; #else cl->avgidle_ = 0; cl->offtime_ = (offtime * nsecPerByte) / 8; #endif /* * If CBQ's WRR is enabled, then initialize the class WRR state. */ if (ifd->wrr_) { ifd->alloc_[cl->pri_] += cl->allotment_ - old_allotment; rmc_wrr_set_weights(ifd); } IFQ_UNLOCK(ifd->ifq_); splx(s); return (0); } /* * static void * rmc_wrr_set_weights(struct rm_ifdat *ifdat) - This function computes * the appropriate run robin weights for the CBQ weighted round robin * algorithm. * * Returns: NONE */ static void rmc_wrr_set_weights(struct rm_ifdat *ifd) { int i; struct rm_class *cl, *clh; for (i = 0; i < RM_MAXPRIO; i++) { /* * This is inverted from that of the simulator to * maintain precision. */ if (ifd->num_[i] == 0) ifd->M_[i] = 0; else ifd->M_[i] = ifd->alloc_[i] / (ifd->num_[i] * ifd->maxpkt_); /* * Compute the weighted allotment for each class. * This takes the expensive div instruction out * of the main loop for the wrr scheduling path. * These only get recomputed when a class comes or * goes. */ if (ifd->active_[i] != NULL) { clh = cl = ifd->active_[i]; do { /* safe-guard for slow link or alloc_ == 0 */ if (ifd->M_[i] == 0) cl->w_allotment_ = 0; else cl->w_allotment_ = cl->allotment_ / ifd->M_[i]; cl = cl->peer_; } while ((cl != NULL) && (cl != clh)); } } } int rmc_get_weight(struct rm_ifdat *ifd, int pri) { if ((pri >= 0) && (pri < RM_MAXPRIO)) return (ifd->M_[pri]); else return (0); } /* * static void * rmc_depth_compute(struct rm_class *cl) - This function computes the * appropriate depth of class 'cl' and its ancestors. * * Returns: NONE */ static void rmc_depth_compute(struct rm_class *cl) { rm_class_t *t = cl, *p; /* * Recompute the depth for the branch of the tree. */ while (t != NULL) { p = t->parent_; if (p && (t->depth_ >= p->depth_)) { p->depth_ = t->depth_ + 1; t = p; } else t = NULL; } } /* * static void * rmc_depth_recompute(struct rm_class *cl) - This function re-computes * the depth of the tree after a class has been deleted. * * Returns: NONE */ static void rmc_depth_recompute(rm_class_t *cl) { #if 1 /* ALTQ */ rm_class_t *p, *t; p = cl; while (p != NULL) { if ((t = p->children_) == NULL) { p->depth_ = 0; } else { int cdepth = 0; while (t != NULL) { if (t->depth_ > cdepth) cdepth = t->depth_; t = t->next_; } if (p->depth_ == cdepth + 1) /* no change to this parent */ return; p->depth_ = cdepth + 1; } p = p->parent_; } #else rm_class_t *t; if (cl->depth_ >= 1) { if (cl->children_ == NULL) { cl->depth_ = 0; } else if ((t = cl->children_) != NULL) { while (t != NULL) { if (t->children_ != NULL) rmc_depth_recompute(t); t = t->next_; } } else rmc_depth_compute(cl); } #endif } /* * void * rmc_delete_class(struct rm_ifdat *ifdat, struct rm_class *cl) - This * function deletes a class from the link-sharing structure and frees * all resources associated with the class. * * Returns: NONE */ void rmc_delete_class(struct rm_ifdat *ifd, struct rm_class *cl) { struct rm_class *p, *head, *previous; int s; ASSERT(cl->children_ == NULL); if (cl->sleeping_) CALLOUT_STOP(&cl->callout_); s = splnet(); IFQ_LOCK(ifd->ifq_); /* * Free packets in the packet queue. * XXX - this may not be a desired behavior. Packets should be * re-queued. */ rmc_dropall(cl); /* * If the class has a parent, then remove the class from the * class from the parent's children chain. */ if (cl->parent_ != NULL) { head = cl->parent_->children_; p = previous = head; if (head->next_ == NULL) { ASSERT(head == cl); cl->parent_->children_ = NULL; cl->parent_->leaf_ = 1; } else while (p != NULL) { if (p == cl) { if (cl == head) cl->parent_->children_ = cl->next_; else previous->next_ = cl->next_; cl->next_ = NULL; p = NULL; } else { previous = p; p = p->next_; } } } /* * Delete class from class priority peer list. */ if ((p = ifd->active_[cl->pri_]) != NULL) { /* * If there is more than one member of this priority * level, then look for class(cl) in the priority level. */ if (p != p->peer_) { while (p->peer_ != cl) p = p->peer_; p->peer_ = cl->peer_; if (ifd->active_[cl->pri_] == cl) ifd->active_[cl->pri_] = cl->peer_; } else { ASSERT(p == cl); ifd->active_[cl->pri_] = NULL; } } /* * Recompute the WRR weights. */ if (ifd->wrr_) { ifd->alloc_[cl->pri_] -= cl->allotment_; ifd->num_[cl->pri_]--; rmc_wrr_set_weights(ifd); } /* * Re-compute the depth of the tree. */ #if 1 /* ALTQ */ rmc_depth_recompute(cl->parent_); #else rmc_depth_recompute(ifd->root_); #endif IFQ_UNLOCK(ifd->ifq_); splx(s); /* * Free the class structure. */ if (cl->red_ != NULL) { #ifdef ALTQ_RIO if (q_is_rio(cl->q_)) rio_destroy((rio_t *)cl->red_); #endif #ifdef ALTQ_RED if (q_is_red(cl->q_)) red_destroy(cl->red_); #endif #ifdef ALTQ_CODEL if (q_is_codel(cl->q_)) codel_destroy(cl->codel_); #endif } free(cl->q_, M_DEVBUF); free(cl, M_DEVBUF); } /* * void * rmc_init(...) - Initialize the resource management data structures * associated with the output portion of interface 'ifp'. 'ifd' is * where the structures will be built (for backwards compatibility, the * structures aren't kept in the ifnet struct). 'nsecPerByte' * gives the link speed (inverse of bandwidth) in nanoseconds/byte. * 'restart' is the driver-specific routine that the generic 'delay * until under limit' action will call to restart output. `maxq' * is the queue size of the 'link' & 'default' classes. 'maxqueued' * is the maximum number of packets that the resource management * code will allow to be queued 'downstream' (this is typically 1). * * Returns: NONE */ void rmc_init(struct ifaltq *ifq, struct rm_ifdat *ifd, u_int nsecPerByte, void (*restart)(struct ifaltq *), int maxq, int maxqueued, u_int maxidle, int minidle, u_int offtime, int flags) { int i, mtu; /* * Initialize the CBQ tracing/debug facility. */ CBQTRACEINIT(); bzero((char *)ifd, sizeof (*ifd)); mtu = ifq->altq_ifp->if_mtu; ifd->ifq_ = ifq; ifd->restart = restart; ifd->maxqueued_ = maxqueued; ifd->ns_per_byte_ = nsecPerByte; ifd->maxpkt_ = mtu; ifd->wrr_ = (flags & RMCF_WRR) ? 1 : 0; ifd->efficient_ = (flags & RMCF_EFFICIENT) ? 1 : 0; #if 1 ifd->maxiftime_ = mtu * nsecPerByte / 1000 * 16; if (mtu * nsecPerByte > 10 * 1000000) ifd->maxiftime_ /= 4; #endif reset_cutoff(ifd); CBQTRACE(rmc_init, 'INIT', ifd->cutoff_); /* * Initialize the CBQ's WRR state. */ for (i = 0; i < RM_MAXPRIO; i++) { ifd->alloc_[i] = 0; ifd->M_[i] = 0; ifd->num_[i] = 0; ifd->na_[i] = 0; ifd->active_[i] = NULL; } /* * Initialize current packet state. */ ifd->qi_ = 0; ifd->qo_ = 0; for (i = 0; i < RM_MAXQUEUED; i++) { ifd->class_[i] = NULL; ifd->curlen_[i] = 0; ifd->borrowed_[i] = NULL; } /* * Create the root class of the link-sharing structure. */ if ((ifd->root_ = rmc_newclass(0, ifd, nsecPerByte, rmc_root_overlimit, maxq, 0, 0, maxidle, minidle, offtime, 0, 0)) == NULL) { printf("rmc_init: root class not allocated\n"); return ; } ifd->root_->depth_ = 0; } /* * void * rmc_queue_packet(struct rm_class *cl, mbuf_t *m) - Add packet given by * mbuf 'm' to queue for resource class 'cl'. This routine is called * by a driver's if_output routine. This routine must be called with * output packet completion interrupts locked out (to avoid racing with * rmc_dequeue_next). * * Returns: 0 on successful queueing * -1 when packet drop occurs */ int rmc_queue_packet(struct rm_class *cl, mbuf_t *m) { struct timeval now; struct rm_ifdat *ifd = cl->ifdat_; int cpri = cl->pri_; int is_empty = qempty(cl->q_); RM_GETTIME(now); if (ifd->cutoff_ > 0) { if (TV_LT(&cl->undertime_, &now)) { if (ifd->cutoff_ > cl->depth_) ifd->cutoff_ = cl->depth_; CBQTRACE(rmc_queue_packet, 'ffoc', cl->depth_); } #if 1 /* ALTQ */ else { /* * the class is overlimit. if the class has * underlimit ancestors, set cutoff to the lowest * depth among them. */ struct rm_class *borrow = cl->borrow_; while (borrow != NULL && borrow->depth_ < ifd->cutoff_) { if (TV_LT(&borrow->undertime_, &now)) { ifd->cutoff_ = borrow->depth_; CBQTRACE(rmc_queue_packet, 'ffob', ifd->cutoff_); break; } borrow = borrow->borrow_; } } #else /* !ALTQ */ else if ((ifd->cutoff_ > 1) && cl->borrow_) { if (TV_LT(&cl->borrow_->undertime_, &now)) { ifd->cutoff_ = cl->borrow_->depth_; CBQTRACE(rmc_queue_packet, 'ffob', cl->borrow_->depth_); } } #endif /* !ALTQ */ } if (_rmc_addq(cl, m) < 0) /* failed */ return (-1); if (is_empty) { CBQTRACE(rmc_queue_packet, 'ytpe', cl->stats_.handle); ifd->na_[cpri]++; } if (qlen(cl->q_) > qlimit(cl->q_)) { /* note: qlimit can be set to 0 or 1 */ rmc_drop_action(cl); return (-1); } return (0); } /* * void * rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now) - Check all * classes to see if there are satified. */ static void rmc_tl_satisfied(struct rm_ifdat *ifd, struct timeval *now) { int i; rm_class_t *p, *bp; for (i = RM_MAXPRIO - 1; i >= 0; i--) { if ((bp = ifd->active_[i]) != NULL) { p = bp; do { if (!rmc_satisfied(p, now)) { ifd->cutoff_ = p->depth_; return; } p = p->peer_; } while (p != bp); } } reset_cutoff(ifd); } /* * rmc_satisfied - Return 1 of the class is satisfied. O, otherwise. */ static int rmc_satisfied(struct rm_class *cl, struct timeval *now) { rm_class_t *p; if (cl == NULL) return (1); if (TV_LT(now, &cl->undertime_)) return (1); if (cl->depth_ == 0) { if (!cl->sleeping_ && (qlen(cl->q_) > cl->qthresh_)) return (0); else return (1); } if (cl->children_ != NULL) { p = cl->children_; while (p != NULL) { if (!rmc_satisfied(p, now)) return (0); p = p->next_; } } return (1); } /* * Return 1 if class 'cl' is under limit or can borrow from a parent, * 0 if overlimit. As a side-effect, this routine will invoke the * class overlimit action if the class if overlimit. */ static int rmc_under_limit(struct rm_class *cl, struct timeval *now) { rm_class_t *p = cl; rm_class_t *top; struct rm_ifdat *ifd = cl->ifdat_; ifd->borrowed_[ifd->qi_] = NULL; /* * If cl is the root class, then always return that it is * underlimit. Otherwise, check to see if the class is underlimit. */ if (cl->parent_ == NULL) return (1); if (cl->sleeping_) { if (TV_LT(now, &cl->undertime_)) return (0); CALLOUT_STOP(&cl->callout_); cl->sleeping_ = 0; cl->undertime_.tv_sec = 0; return (1); } top = NULL; while (cl->undertime_.tv_sec && TV_LT(now, &cl->undertime_)) { if (((cl = cl->borrow_) == NULL) || (cl->depth_ > ifd->cutoff_)) { #ifdef ADJUST_CUTOFF if (cl != NULL) /* cutoff is taking effect, just return false without calling the delay action. */ return (0); #endif #ifdef BORROW_OFFTIME /* * check if the class can borrow offtime too. * borrow offtime from the top of the borrow * chain if the top class is not overloaded. */ if (cl != NULL) { /* cutoff is taking effect, use this class as top. */ top = cl; CBQTRACE(rmc_under_limit, 'ffou', ifd->cutoff_); } if (top != NULL && top->avgidle_ == top->minidle_) top = NULL; p->overtime_ = *now; (p->overlimit)(p, top); #else p->overtime_ = *now; (p->overlimit)(p, NULL); #endif return (0); } top = cl; } if (cl != p) ifd->borrowed_[ifd->qi_] = cl; return (1); } /* * _rmc_wrr_dequeue_next() - This is scheduler for WRR as opposed to * Packet-by-packet round robin. * * The heart of the weighted round-robin scheduler, which decides which * class next gets to send a packet. Highest priority first, then * weighted round-robin within priorites. * * Each able-to-send class gets to send until its byte allocation is * exhausted. Thus, the active pointer is only changed after a class has * exhausted its allocation. * * If the scheduler finds no class that is underlimit or able to borrow, * then the first class found that had a nonzero queue and is allowed to * borrow gets to send. */ static mbuf_t * _rmc_wrr_dequeue_next(struct rm_ifdat *ifd, int op) { struct rm_class *cl = NULL, *first = NULL; u_int deficit; int cpri; mbuf_t *m; struct timeval now; RM_GETTIME(now); /* * if the driver polls the top of the queue and then removes * the polled packet, we must return the same packet. */ if (op == ALTDQ_REMOVE && ifd->pollcache_) { cl = ifd->pollcache_; cpri = cl->pri_; if (ifd->efficient_) { /* check if this class is overlimit */ if (cl->undertime_.tv_sec != 0 && rmc_under_limit(cl, &now) == 0) first = cl; } ifd->pollcache_ = NULL; goto _wrr_out; } else { /* mode == ALTDQ_POLL || pollcache == NULL */ ifd->pollcache_ = NULL; ifd->borrowed_[ifd->qi_] = NULL; } #ifdef ADJUST_CUTOFF _again: #endif for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) { if (ifd->na_[cpri] == 0) continue; deficit = 0; /* * Loop through twice for a priority level, if some class * was unable to send a packet the first round because * of the weighted round-robin mechanism. * During the second loop at this level, deficit==2. * (This second loop is not needed if for every class, * "M[cl->pri_])" times "cl->allotment" is greater than * the byte size for the largest packet in the class.) */ _wrr_loop: cl = ifd->active_[cpri]; ASSERT(cl != NULL); do { if ((deficit < 2) && (cl->bytes_alloc_ <= 0)) cl->bytes_alloc_ += cl->w_allotment_; if (!qempty(cl->q_)) { if ((cl->undertime_.tv_sec == 0) || rmc_under_limit(cl, &now)) { if (cl->bytes_alloc_ > 0 || deficit > 1) goto _wrr_out; /* underlimit but no alloc */ deficit = 1; #if 1 ifd->borrowed_[ifd->qi_] = NULL; #endif } else if (first == NULL && cl->borrow_ != NULL) first = cl; /* borrowing candidate */ } cl->bytes_alloc_ = 0; cl = cl->peer_; } while (cl != ifd->active_[cpri]); if (deficit == 1) { /* first loop found an underlimit class with deficit */ /* Loop on same priority level, with new deficit. */ deficit = 2; goto _wrr_loop; } } #ifdef ADJUST_CUTOFF /* * no underlimit class found. if cutoff is taking effect, * increase cutoff and try again. */ if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) { ifd->cutoff_++; CBQTRACE(_rmc_wrr_dequeue_next, 'ojda', ifd->cutoff_); goto _again; } #endif /* ADJUST_CUTOFF */ /* * If LINK_EFFICIENCY is turned on, then the first overlimit * class we encounter will send a packet if all the classes * of the link-sharing structure are overlimit. */ reset_cutoff(ifd); CBQTRACE(_rmc_wrr_dequeue_next, 'otsr', ifd->cutoff_); if (!ifd->efficient_ || first == NULL) return (NULL); cl = first; cpri = cl->pri_; #if 0 /* too time-consuming for nothing */ if (cl->sleeping_) CALLOUT_STOP(&cl->callout_); cl->sleeping_ = 0; cl->undertime_.tv_sec = 0; #endif ifd->borrowed_[ifd->qi_] = cl->borrow_; ifd->cutoff_ = cl->borrow_->depth_; /* * Deque the packet and do the book keeping... */ _wrr_out: if (op == ALTDQ_REMOVE) { m = _rmc_getq(cl); if (m == NULL) panic("_rmc_wrr_dequeue_next"); if (qempty(cl->q_)) ifd->na_[cpri]--; /* * Update class statistics and link data. */ if (cl->bytes_alloc_ > 0) cl->bytes_alloc_ -= m_pktlen(m); if ((cl->bytes_alloc_ <= 0) || first == cl) ifd->active_[cl->pri_] = cl->peer_; else ifd->active_[cl->pri_] = cl; ifd->class_[ifd->qi_] = cl; ifd->curlen_[ifd->qi_] = m_pktlen(m); ifd->now_[ifd->qi_] = now; ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_; ifd->queued_++; } else { /* mode == ALTDQ_PPOLL */ m = _rmc_pollq(cl); ifd->pollcache_ = cl; } return (m); } /* * Dequeue & return next packet from the highest priority class that * has a packet to send & has enough allocation to send it. This * routine is called by a driver whenever it needs a new packet to * output. */ static mbuf_t * _rmc_prr_dequeue_next(struct rm_ifdat *ifd, int op) { mbuf_t *m; int cpri; struct rm_class *cl, *first = NULL; struct timeval now; RM_GETTIME(now); /* * if the driver polls the top of the queue and then removes * the polled packet, we must return the same packet. */ if (op == ALTDQ_REMOVE && ifd->pollcache_) { cl = ifd->pollcache_; cpri = cl->pri_; ifd->pollcache_ = NULL; goto _prr_out; } else { /* mode == ALTDQ_POLL || pollcache == NULL */ ifd->pollcache_ = NULL; ifd->borrowed_[ifd->qi_] = NULL; } #ifdef ADJUST_CUTOFF _again: #endif for (cpri = RM_MAXPRIO - 1; cpri >= 0; cpri--) { if (ifd->na_[cpri] == 0) continue; cl = ifd->active_[cpri]; ASSERT(cl != NULL); do { if (!qempty(cl->q_)) { if ((cl->undertime_.tv_sec == 0) || rmc_under_limit(cl, &now)) goto _prr_out; if (first == NULL && cl->borrow_ != NULL) first = cl; } cl = cl->peer_; } while (cl != ifd->active_[cpri]); } #ifdef ADJUST_CUTOFF /* * no underlimit class found. if cutoff is taking effect, increase * cutoff and try again. */ if (first != NULL && ifd->cutoff_ < ifd->root_->depth_) { ifd->cutoff_++; goto _again; } #endif /* ADJUST_CUTOFF */ /* * If LINK_EFFICIENCY is turned on, then the first overlimit * class we encounter will send a packet if all the classes * of the link-sharing structure are overlimit. */ reset_cutoff(ifd); if (!ifd->efficient_ || first == NULL) return (NULL); cl = first; cpri = cl->pri_; #if 0 /* too time-consuming for nothing */ if (cl->sleeping_) CALLOUT_STOP(&cl->callout_); cl->sleeping_ = 0; cl->undertime_.tv_sec = 0; #endif ifd->borrowed_[ifd->qi_] = cl->borrow_; ifd->cutoff_ = cl->borrow_->depth_; /* * Deque the packet and do the book keeping... */ _prr_out: if (op == ALTDQ_REMOVE) { m = _rmc_getq(cl); if (m == NULL) panic("_rmc_prr_dequeue_next"); if (qempty(cl->q_)) ifd->na_[cpri]--; ifd->active_[cpri] = cl->peer_; ifd->class_[ifd->qi_] = cl; ifd->curlen_[ifd->qi_] = m_pktlen(m); ifd->now_[ifd->qi_] = now; ifd->qi_ = (ifd->qi_ + 1) % ifd->maxqueued_; ifd->queued_++; } else { /* mode == ALTDQ_POLL */ m = _rmc_pollq(cl); ifd->pollcache_ = cl; } return (m); } /* * mbuf_t * * rmc_dequeue_next(struct rm_ifdat *ifd, struct timeval *now) - this function * is invoked by the packet driver to get the next packet to be * dequeued and output on the link. If WRR is enabled, then the * WRR dequeue next routine will determine the next packet to sent. * Otherwise, packet-by-packet round robin is invoked. * * Returns: NULL, if a packet is not available or if all * classes are overlimit. * * Otherwise, Pointer to the next packet. */ mbuf_t * rmc_dequeue_next(struct rm_ifdat *ifd, int mode) { if (ifd->queued_ >= ifd->maxqueued_) return (NULL); else if (ifd->wrr_) return (_rmc_wrr_dequeue_next(ifd, mode)); else return (_rmc_prr_dequeue_next(ifd, mode)); } /* * Update the utilization estimate for the packet that just completed. * The packet's class & the parent(s) of that class all get their * estimators updated. This routine is called by the driver's output- * packet-completion interrupt service routine. */ /* * a macro to approximate "divide by 1000" that gives 0.000999, * if a value has enough effective digits. * (on pentium, mul takes 9 cycles but div takes 46!) */ #define NSEC_TO_USEC(t) (((t) >> 10) + ((t) >> 16) + ((t) >> 17)) void rmc_update_class_util(struct rm_ifdat *ifd) { int idle, avgidle, pktlen; int pkt_time, tidle; rm_class_t *cl, *borrowed; rm_class_t *borrows; struct timeval *nowp; /* * Get the most recent completed class. */ if ((cl = ifd->class_[ifd->qo_]) == NULL) return; pktlen = ifd->curlen_[ifd->qo_]; borrowed = ifd->borrowed_[ifd->qo_]; borrows = borrowed; PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen); /* * Run estimator on class and its ancestors. */ /* * rm_update_class_util is designed to be called when the * transfer is completed from a xmit complete interrupt, * but most drivers don't implement an upcall for that. * so, just use estimated completion time. * as a result, ifd->qi_ and ifd->qo_ are always synced. */ nowp = &ifd->now_[ifd->qo_]; /* get pkt_time (for link) in usec */ #if 1 /* use approximation */ pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_; pkt_time = NSEC_TO_USEC(pkt_time); #else pkt_time = ifd->curlen_[ifd->qo_] * ifd->ns_per_byte_ / 1000; #endif #if 1 /* ALTQ4PPP */ if (TV_LT(nowp, &ifd->ifnow_)) { int iftime; /* * make sure the estimated completion time does not go * too far. it can happen when the link layer supports * data compression or the interface speed is set to * a much lower value. */ TV_DELTA(&ifd->ifnow_, nowp, iftime); if (iftime+pkt_time < ifd->maxiftime_) { TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_); } else { TV_ADD_DELTA(nowp, ifd->maxiftime_, &ifd->ifnow_); } } else { TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_); } #else if (TV_LT(nowp, &ifd->ifnow_)) { TV_ADD_DELTA(&ifd->ifnow_, pkt_time, &ifd->ifnow_); } else { TV_ADD_DELTA(nowp, pkt_time, &ifd->ifnow_); } #endif while (cl != NULL) { TV_DELTA(&ifd->ifnow_, &cl->last_, idle); if (idle >= 2000000) /* * this class is idle enough, reset avgidle. * (TV_DELTA returns 2000000 us when delta is large.) */ cl->avgidle_ = cl->maxidle_; /* get pkt_time (for class) in usec */ #if 1 /* use approximation */ pkt_time = pktlen * cl->ns_per_byte_; pkt_time = NSEC_TO_USEC(pkt_time); #else pkt_time = pktlen * cl->ns_per_byte_ / 1000; #endif idle -= pkt_time; avgidle = cl->avgidle_; avgidle += idle - (avgidle >> RM_FILTER_GAIN); cl->avgidle_ = avgidle; /* Are we overlimit ? */ if (avgidle <= 0) { CBQTRACE(rmc_update_class_util, 'milo', cl->stats_.handle); #if 1 /* ALTQ */ /* * need some lower bound for avgidle, otherwise * a borrowing class gets unbounded penalty. */ if (avgidle < cl->minidle_) avgidle = cl->avgidle_ = cl->minidle_; #endif /* set next idle to make avgidle 0 */ tidle = pkt_time + (((1 - RM_POWER) * avgidle) >> RM_FILTER_GAIN); TV_ADD_DELTA(nowp, tidle, &cl->undertime_); ++cl->stats_.over; } else { cl->avgidle_ = (avgidle > cl->maxidle_) ? cl->maxidle_ : avgidle; cl->undertime_.tv_sec = 0; if (cl->sleeping_) { CALLOUT_STOP(&cl->callout_); cl->sleeping_ = 0; } } if (borrows != NULL) { if (borrows != cl) ++cl->stats_.borrows; else borrows = NULL; } cl->last_ = ifd->ifnow_; cl->last_pkttime_ = pkt_time; #if 1 if (cl->parent_ == NULL) { /* take stats of root class */ PKTCNTR_ADD(&cl->stats_.xmit_cnt, pktlen); } #endif cl = cl->parent_; } /* * Check to see if cutoff needs to set to a new level. */ cl = ifd->class_[ifd->qo_]; if (borrowed && (ifd->cutoff_ >= borrowed->depth_)) { #if 1 /* ALTQ */ if ((qlen(cl->q_) <= 0) || TV_LT(nowp, &borrowed->undertime_)) { rmc_tl_satisfied(ifd, nowp); CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_); } else { ifd->cutoff_ = borrowed->depth_; CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_); } #else /* !ALTQ */ if ((qlen(cl->q_) <= 1) || TV_LT(&now, &borrowed->undertime_)) { reset_cutoff(ifd); #ifdef notdef rmc_tl_satisfied(ifd, &now); #endif CBQTRACE(rmc_update_class_util, 'broe', ifd->cutoff_); } else { ifd->cutoff_ = borrowed->depth_; CBQTRACE(rmc_update_class_util, 'ffob', borrowed->depth_); } #endif /* !ALTQ */ } /* * Release class slot */ ifd->borrowed_[ifd->qo_] = NULL; ifd->class_[ifd->qo_] = NULL; ifd->qo_ = (ifd->qo_ + 1) % ifd->maxqueued_; ifd->queued_--; } /* * void * rmc_drop_action(struct rm_class *cl) - Generic (not protocol-specific) * over-limit action routines. These get invoked by rmc_under_limit() * if a class with packets to send if over its bandwidth limit & can't * borrow from a parent class. * * Returns: NONE */ static void rmc_drop_action(struct rm_class *cl) { struct rm_ifdat *ifd = cl->ifdat_; ASSERT(qlen(cl->q_) > 0); _rmc_dropq(cl); if (qempty(cl->q_)) ifd->na_[cl->pri_]--; } void rmc_dropall(struct rm_class *cl) { struct rm_ifdat *ifd = cl->ifdat_; if (!qempty(cl->q_)) { _flushq(cl->q_); ifd->na_[cl->pri_]--; } } #if (__FreeBSD_version > 300000) /* hzto() is removed from FreeBSD-3.0 */ static int hzto(struct timeval *); static int hzto(tv) struct timeval *tv; { struct timeval t2; getmicrotime(&t2); t2.tv_sec = tv->tv_sec - t2.tv_sec; t2.tv_usec = tv->tv_usec - t2.tv_usec; return (tvtohz(&t2)); } #endif /* __FreeBSD_version > 300000 */ /* * void * rmc_delay_action(struct rm_class *cl) - This function is the generic CBQ * delay action routine. It is invoked via rmc_under_limit when the * packet is discoverd to be overlimit. * * If the delay action is result of borrow class being overlimit, then * delay for the offtime of the borrowing class that is overlimit. * * Returns: NONE */ void rmc_delay_action(struct rm_class *cl, struct rm_class *borrow) { int delay, t, extradelay; cl->stats_.overactions++; TV_DELTA(&cl->undertime_, &cl->overtime_, delay); #ifndef BORROW_OFFTIME delay += cl->offtime_; #endif if (!cl->sleeping_) { CBQTRACE(rmc_delay_action, 'yled', cl->stats_.handle); #ifdef BORROW_OFFTIME if (borrow != NULL) extradelay = borrow->offtime_; else #endif extradelay = cl->offtime_; #ifdef ALTQ /* * XXX recalculate suspend time: * current undertime is (tidle + pkt_time) calculated * from the last transmission. * tidle: time required to bring avgidle back to 0 * pkt_time: target waiting time for this class * we need to replace pkt_time by offtime */ extradelay -= cl->last_pkttime_; #endif if (extradelay > 0) { TV_ADD_DELTA(&cl->undertime_, extradelay, &cl->undertime_); delay += extradelay; } cl->sleeping_ = 1; cl->stats_.delays++; /* * Since packets are phased randomly with respect to the * clock, 1 tick (the next clock tick) can be an arbitrarily * short time so we have to wait for at least two ticks. * NOTE: If there's no other traffic, we need the timer as * a 'backstop' to restart this class. */ if (delay > tick * 2) { /* FreeBSD rounds up the tick */ t = hzto(&cl->undertime_); } else t = 2; CALLOUT_RESET(&cl->callout_, t, rmc_restart, cl); } } /* * void * rmc_restart() - is just a helper routine for rmc_delay_action -- it is * called by the system timer code & is responsible checking if the * class is still sleeping (it might have been restarted as a side * effect of the queue scan on a packet arrival) and, if so, restarting * output for the class. Inspecting the class state & restarting output * require locking the class structure. In general the driver is * responsible for locking but this is the only routine that is not * called directly or indirectly from the interface driver so it has * know about system locking conventions. Under bsd, locking is done * by raising IPL to splimp so that's what's implemented here. On a * different system this would probably need to be changed. * * Returns: NONE */ static void rmc_restart(void *arg) { struct rm_class *cl = arg; struct rm_ifdat *ifd = cl->ifdat_; struct epoch_tracker et; int s; s = splnet(); NET_EPOCH_ENTER(et); IFQ_LOCK(ifd->ifq_); CURVNET_SET(ifd->ifq_->altq_ifp->if_vnet); if (cl->sleeping_) { cl->sleeping_ = 0; cl->undertime_.tv_sec = 0; if (ifd->queued_ < ifd->maxqueued_ && ifd->restart != NULL) { CBQTRACE(rmc_restart, 'trts', cl->stats_.handle); (ifd->restart)(ifd->ifq_); } } CURVNET_RESTORE(); IFQ_UNLOCK(ifd->ifq_); NET_EPOCH_EXIT(et); splx(s); } /* * void * rmc_root_overlimit(struct rm_class *cl) - This the generic overlimit * handling routine for the root class of the link sharing structure. * * Returns: NONE */ static void rmc_root_overlimit(struct rm_class *cl, struct rm_class *borrow) { panic("rmc_root_overlimit"); } /* * Packet Queue handling routines. Eventually, this is to localize the * effects on the code whether queues are red queues or droptail * queues. */ static int _rmc_addq(rm_class_t *cl, mbuf_t *m) { #ifdef ALTQ_RIO if (q_is_rio(cl->q_)) return rio_addq((rio_t *)cl->red_, cl->q_, m, cl->pktattr_); #endif #ifdef ALTQ_RED if (q_is_red(cl->q_)) return red_addq(cl->red_, cl->q_, m, cl->pktattr_); #endif /* ALTQ_RED */ #ifdef ALTQ_CODEL if (q_is_codel(cl->q_)) return codel_addq(cl->codel_, cl->q_, m); #endif if (cl->flags_ & RMCF_CLEARDSCP) write_dsfield(m, cl->pktattr_, 0); _addq(cl->q_, m); return (0); } /* note: _rmc_dropq is not called for red */ static void _rmc_dropq(rm_class_t *cl) { mbuf_t *m; if ((m = _getq(cl->q_)) != NULL) m_freem(m); } static mbuf_t * _rmc_getq(rm_class_t *cl) { #ifdef ALTQ_RIO if (q_is_rio(cl->q_)) return rio_getq((rio_t *)cl->red_, cl->q_); #endif #ifdef ALTQ_RED if (q_is_red(cl->q_)) return red_getq(cl->red_, cl->q_); #endif #ifdef ALTQ_CODEL if (q_is_codel(cl->q_)) return codel_getq(cl->codel_, cl->q_); #endif return _getq(cl->q_); } static mbuf_t * _rmc_pollq(rm_class_t *cl) { return qhead(cl->q_); } #ifdef CBQ_TRACE struct cbqtrace cbqtrace_buffer[NCBQTRACE+1]; struct cbqtrace *cbqtrace_ptr = NULL; int cbqtrace_count; /* * DDB hook to trace cbq events: * the last 1024 events are held in a circular buffer. * use "call cbqtrace_dump(N)" to display 20 events from Nth event. */ void cbqtrace_dump(int); static char *rmc_funcname(void *); static struct rmc_funcs { void *func; char *name; } rmc_funcs[] = { rmc_init, "rmc_init", rmc_queue_packet, "rmc_queue_packet", rmc_under_limit, "rmc_under_limit", rmc_update_class_util, "rmc_update_class_util", rmc_delay_action, "rmc_delay_action", rmc_restart, "rmc_restart", _rmc_wrr_dequeue_next, "_rmc_wrr_dequeue_next", NULL, NULL }; static char *rmc_funcname(void *func) { struct rmc_funcs *fp; for (fp = rmc_funcs; fp->func != NULL; fp++) if (fp->func == func) return (fp->name); return ("unknown"); } void cbqtrace_dump(int counter) { int i, *p; char *cp; counter = counter % NCBQTRACE; p = (int *)&cbqtrace_buffer[counter]; for (i=0; i<20; i++) { printf("[0x%x] ", *p++); printf("%s: ", rmc_funcname((void *)*p++)); cp = (char *)p++; printf("%c%c%c%c: ", cp[0], cp[1], cp[2], cp[3]); printf("%d\n",*p++); if (p >= (int *)&cbqtrace_buffer[NCBQTRACE]) p = (int *)cbqtrace_buffer; } } #endif /* CBQ_TRACE */ #endif /* ALTQ_CBQ */ #if defined(ALTQ_CBQ) || defined(ALTQ_RED) || defined(ALTQ_RIO) || \ defined(ALTQ_HFSC) || defined(ALTQ_PRIQ) || defined(ALTQ_CODEL) #if !defined(__GNUC__) || defined(ALTQ_DEBUG) void _addq(class_queue_t *q, mbuf_t *m) { mbuf_t *m0; if ((m0 = qtail(q)) != NULL) m->m_nextpkt = m0->m_nextpkt; else m0 = m; m0->m_nextpkt = m; qtail(q) = m; qlen(q)++; } mbuf_t * _getq(class_queue_t *q) { mbuf_t *m, *m0; if ((m = qtail(q)) == NULL) return (NULL); if ((m0 = m->m_nextpkt) != m) m->m_nextpkt = m0->m_nextpkt; else { ASSERT(qlen(q) == 1); qtail(q) = NULL; } qlen(q)--; m0->m_nextpkt = NULL; return (m0); } /* drop a packet at the tail of the queue */ mbuf_t * _getq_tail(class_queue_t *q) { mbuf_t *m, *m0, *prev; if ((m = m0 = qtail(q)) == NULL) return NULL; do { prev = m0; m0 = m0->m_nextpkt; } while (m0 != m); prev->m_nextpkt = m->m_nextpkt; if (prev == m) { ASSERT(qlen(q) == 1); qtail(q) = NULL; } else qtail(q) = prev; qlen(q)--; m->m_nextpkt = NULL; return (m); } /* randomly select a packet in the queue */ mbuf_t * _getq_random(class_queue_t *q) { struct mbuf *m; int i, n; if ((m = qtail(q)) == NULL) return NULL; if (m->m_nextpkt == m) { ASSERT(qlen(q) == 1); qtail(q) = NULL; } else { struct mbuf *prev = NULL; n = arc4random() % qlen(q) + 1; for (i = 0; i < n; i++) { prev = m; m = m->m_nextpkt; } prev->m_nextpkt = m->m_nextpkt; if (m == qtail(q)) qtail(q) = prev; } qlen(q)--; m->m_nextpkt = NULL; return (m); } void _removeq(class_queue_t *q, mbuf_t *m) { mbuf_t *m0, *prev; m0 = qtail(q); do { prev = m0; m0 = m0->m_nextpkt; } while (m0 != m); prev->m_nextpkt = m->m_nextpkt; if (prev == m) qtail(q) = NULL; else if (qtail(q) == m) qtail(q) = prev; qlen(q)--; } void _flushq(class_queue_t *q) { mbuf_t *m; while ((m = _getq(q)) != NULL) m_freem(m); ASSERT(qlen(q) == 0); } #endif /* !__GNUC__ || ALTQ_DEBUG */ #endif /* ALTQ_CBQ || ALTQ_RED || ALTQ_RIO || ALTQ_HFSC || ALTQ_PRIQ */