/* $OpenBSD: altq_red.c,v 1.2 2001/08/09 14:32:59 deraadt Exp $ */ /* $KAME: altq_red.c,v 1.8 2000/12/14 08:12:46 thorpej Exp $ */ /* * Copyright (C) 1997-2000 * Sony Computer Science Laboratories Inc. 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 SONY CSL 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 SONY CSL 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. * */ /* * Copyright (c) 1990-1994 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 Computer Systems * Engineering 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. */ #include #include #include #include #include #include #include #include #include #ifdef ALTQ_FLOWVALVE #include #include #endif #include #include #include #include #include #ifdef INET6 #include #endif #include #include #include #ifdef ALTQ_FLOWVALVE #include #endif /* * ALTQ/RED (Random Early Detection) implementation using 32-bit * fixed-point calculation. * * written by kjc using the ns code as a reference. * you can learn more about red and ns from Sally's home page at * http://www-nrg.ee.lbl.gov/floyd/ * * most of the red parameter values are fixed in this implementation * to prevent fixed-point overflow/underflow. * if you change the parameters, watch out for overflow/underflow! * * the parameters used are recommended values by Sally. * the corresponding ns config looks: * q_weight=0.00195 * minthresh=5 maxthresh=15 queue-size=60 * linterm=30 * dropmech=drop-tail * bytes=false (can't be handled by 32-bit fixed-point) * doubleq=false dqthresh=false * wait=true */ /* * alternative red parameters for a slow link. * * assume the queue length becomes from zero to L and keeps L, it takes * N packets for q_avg to reach 63% of L. * when q_weight is 0.002, N is about 500 packets. * for a slow link like dial-up, 500 packets takes more than 1 minute! * when q_weight is 0.008, N is about 127 packets. * when q_weight is 0.016, N is about 63 packets. * bursts of 50 packets are allowd for 0.002, bursts of 25 packets * are allowed for 0.016. * see Sally's paper for more details. */ /* normal red parameters */ #define W_WEIGHT 512 /* inverse of weight of EWMA (511/512) */ /* q_weight = 0.00195 */ /* red parameters for a slow link */ #define W_WEIGHT_1 128 /* inverse of weight of EWMA (127/128) */ /* q_weight = 0.0078125 */ /* red parameters for a very slow link (e.g., dialup) */ #define W_WEIGHT_2 64 /* inverse of weight of EWMA (63/64) */ /* q_weight = 0.015625 */ /* fixed-point uses 12-bit decimal places */ #define FP_SHIFT 12 /* fixed-point shift */ /* red parameters for drop probability */ #define INV_P_MAX 10 /* inverse of max drop probability */ #define TH_MIN 5 /* min threshold */ #define TH_MAX 15 /* max threshold */ #define RED_LIMIT 60 /* default max queue lenght */ #define RED_STATS /* collect statistics */ /* * our default policy for forced-drop is drop-tail. * (in altq-1.1.2 or earlier, the default was random-drop. * but it makes more sense to punish the cause of the surge.) * to switch to the random-drop policy, define "RED_RANDOM_DROP". */ #ifdef ALTQ_FLOWVALVE /* * flow-valve is an extention to protect red from unresponsive flows * and to promote end-to-end congestion control. * flow-valve observes the average drop rates of the flows that have * experienced packet drops in the recent past. * when the average drop rate exceeds the threshold, the flow is * blocked by the flow-valve. the trapped flow should back off * exponentially to escape from the flow-valve. */ #ifdef RED_RANDOM_DROP #error "random-drop can't be used with flow-valve!" #endif #endif /* ALTQ_FLOWVALVE */ /* red_list keeps all red_queue_t's allocated. */ static red_queue_t *red_list = NULL; /* default red parameter values */ static int default_th_min = TH_MIN; static int default_th_max = TH_MAX; static int default_inv_pmax = INV_P_MAX; /* internal function prototypes */ static int red_enqueue __P((struct ifaltq *, struct mbuf *, struct altq_pktattr *)); static struct mbuf *red_dequeue __P((struct ifaltq *, int)); static int red_request __P((struct ifaltq *, int, void *)); static void red_purgeq __P((red_queue_t *)); static int red_detach __P((red_queue_t *)); #ifdef ALTQ_FLOWVALVE static __inline struct fve *flowlist_lookup __P((struct flowvalve *, struct altq_pktattr *, struct timeval *)); static __inline struct fve *flowlist_reclaim __P((struct flowvalve *, struct altq_pktattr *)); static __inline void flowlist_move_to_head __P((struct flowvalve *, struct fve *)); static __inline int fv_p2f __P((struct flowvalve *, int)); static struct flowvalve *fv_alloc __P((struct red *)); static void fv_destroy __P((struct flowvalve *)); static int fv_checkflow __P((struct flowvalve *, struct altq_pktattr *, struct fve **)); static void fv_dropbyred __P((struct flowvalve *fv, struct altq_pktattr *, struct fve *)); #endif /* * red device interface */ altqdev_decl(red); int redopen(dev, flag, fmt, p) dev_t dev; int flag, fmt; struct proc *p; { /* everything will be done when the queueing scheme is attached. */ return 0; } int redclose(dev, flag, fmt, p) dev_t dev; int flag, fmt; struct proc *p; { red_queue_t *rqp; int err, error = 0; while ((rqp = red_list) != NULL) { /* destroy all */ err = red_detach(rqp); if (err != 0 && error == 0) error = err; } return error; } int redioctl(dev, cmd, addr, flag, p) dev_t dev; ioctlcmd_t cmd; caddr_t addr; int flag; struct proc *p; { red_queue_t *rqp; struct red_interface *ifacep; struct ifnet *ifp; int error = 0; /* check super-user privilege */ switch (cmd) { case RED_GETSTATS: break; default: #if (__FreeBSD_version > 400000) if ((error = suser(p)) != 0) #else if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) #endif return (error); break; } switch (cmd) { case RED_ENABLE: ifacep = (struct red_interface *)addr; if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) { error = EBADF; break; } error = altq_enable(rqp->rq_ifq); break; case RED_DISABLE: ifacep = (struct red_interface *)addr; if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) { error = EBADF; break; } error = altq_disable(rqp->rq_ifq); break; case RED_IF_ATTACH: ifp = ifunit(((struct red_interface *)addr)->red_ifname); if (ifp == NULL) { error = ENXIO; break; } /* allocate and initialize red_queue_t */ MALLOC(rqp, red_queue_t *, sizeof(red_queue_t), M_DEVBUF, M_WAITOK); if (rqp == NULL) { error = ENOMEM; break; } bzero(rqp, sizeof(red_queue_t)); MALLOC(rqp->rq_q, class_queue_t *, sizeof(class_queue_t), M_DEVBUF, M_WAITOK); if (rqp->rq_q == NULL) { FREE(rqp, M_DEVBUF); error = ENOMEM; break; } bzero(rqp->rq_q, sizeof(class_queue_t)); rqp->rq_red = red_alloc(0, 0, 0, 0, 0, 0); if (rqp->rq_red == NULL) { FREE(rqp->rq_q, M_DEVBUF); FREE(rqp, M_DEVBUF); error = ENOMEM; break; } rqp->rq_ifq = &ifp->if_snd; qtail(rqp->rq_q) = NULL; qlen(rqp->rq_q) = 0; qlimit(rqp->rq_q) = RED_LIMIT; qtype(rqp->rq_q) = Q_RED; /* * set RED to this ifnet structure. */ error = altq_attach(rqp->rq_ifq, ALTQT_RED, rqp, red_enqueue, red_dequeue, red_request, NULL, NULL); if (error) { red_destroy(rqp->rq_red); FREE(rqp->rq_q, M_DEVBUF); FREE(rqp, M_DEVBUF); break; } /* add this state to the red list */ rqp->rq_next = red_list; red_list = rqp; break; case RED_IF_DETACH: ifacep = (struct red_interface *)addr; if ((rqp = altq_lookup(ifacep->red_ifname, ALTQT_RED)) == NULL) { error = EBADF; break; } error = red_detach(rqp); break; case RED_GETSTATS: do { struct red_stats *q_stats; red_t *rp; q_stats = (struct red_stats *)addr; if ((rqp = altq_lookup(q_stats->iface.red_ifname, ALTQT_RED)) == NULL) { error = EBADF; break; } q_stats->q_len = qlen(rqp->rq_q); q_stats->q_limit = qlimit(rqp->rq_q); rp = rqp->rq_red; q_stats->q_avg = rp->red_avg >> rp->red_wshift; q_stats->xmit_cnt = rp->red_stats.xmit_cnt; q_stats->drop_cnt = rp->red_stats.drop_cnt; q_stats->drop_forced = rp->red_stats.drop_forced; q_stats->drop_unforced = rp->red_stats.drop_unforced; q_stats->marked_packets = rp->red_stats.marked_packets; q_stats->weight = rp->red_weight; q_stats->inv_pmax = rp->red_inv_pmax; q_stats->th_min = rp->red_thmin; q_stats->th_max = rp->red_thmax; #ifdef ALTQ_FLOWVALVE if (rp->red_flowvalve != NULL) { struct flowvalve *fv = rp->red_flowvalve; q_stats->fv_flows = fv->fv_flows; q_stats->fv_pass = fv->fv_stats.pass; q_stats->fv_predrop = fv->fv_stats.predrop; q_stats->fv_alloc = fv->fv_stats.alloc; q_stats->fv_escape = fv->fv_stats.escape; } else { #endif /* ALTQ_FLOWVALVE */ q_stats->fv_flows = 0; q_stats->fv_pass = 0; q_stats->fv_predrop = 0; q_stats->fv_alloc = 0; q_stats->fv_escape = 0; #ifdef ALTQ_FLOWVALVE } #endif /* ALTQ_FLOWVALVE */ } while (0); break; case RED_CONFIG: do { struct red_conf *fc; red_t *new; int s, limit; fc = (struct red_conf *)addr; if ((rqp = altq_lookup(fc->iface.red_ifname, ALTQT_RED)) == NULL) { error = EBADF; break; } new = red_alloc(fc->red_weight, fc->red_inv_pmax, fc->red_thmin, fc->red_thmax, fc->red_flags, fc->red_pkttime); if (new == NULL) { error = ENOMEM; break; } s = splimp(); red_purgeq(rqp); limit = fc->red_limit; if (limit < fc->red_thmax) limit = fc->red_thmax; qlimit(rqp->rq_q) = limit; fc->red_limit = limit; /* write back the new value */ red_destroy(rqp->rq_red); rqp->rq_red = new; splx(s); /* write back new values */ fc->red_limit = limit; fc->red_inv_pmax = rqp->rq_red->red_inv_pmax; fc->red_thmin = rqp->rq_red->red_thmin; fc->red_thmax = rqp->rq_red->red_thmax; } while (0); break; case RED_SETDEFAULTS: do { struct redparams *rp; rp = (struct redparams *)addr; default_th_min = rp->th_min; default_th_max = rp->th_max; default_inv_pmax = rp->inv_pmax; } while (0); break; default: error = EINVAL; break; } return error; } static int red_detach(rqp) red_queue_t *rqp; { red_queue_t *tmp; int error = 0; if (ALTQ_IS_ENABLED(rqp->rq_ifq)) altq_disable(rqp->rq_ifq); if ((error = altq_detach(rqp->rq_ifq))) return (error); if (red_list == rqp) red_list = rqp->rq_next; else { for (tmp = red_list; tmp != NULL; tmp = tmp->rq_next) if (tmp->rq_next == rqp) { tmp->rq_next = rqp->rq_next; break; } if (tmp == NULL) printf("red_detach: no state found in red_list!\n"); } red_destroy(rqp->rq_red); FREE(rqp->rq_q, M_DEVBUF); FREE(rqp, M_DEVBUF); return (error); } /* * red support routines */ red_t * red_alloc(weight, inv_pmax, th_min, th_max, flags, pkttime) int weight, inv_pmax, th_min, th_max; int flags, pkttime; { red_t *rp; int w, i; int npkts_per_sec; MALLOC(rp, red_t *, sizeof(red_t), M_DEVBUF, M_WAITOK); if (rp == NULL) return (NULL); bzero(rp, sizeof(red_t)); rp->red_avg = 0; rp->red_idle = 1; if (weight == 0) rp->red_weight = W_WEIGHT; else rp->red_weight = weight; if (inv_pmax == 0) rp->red_inv_pmax = default_inv_pmax; else rp->red_inv_pmax = inv_pmax; if (th_min == 0) rp->red_thmin = default_th_min; else rp->red_thmin = th_min; if (th_max == 0) rp->red_thmax = default_th_max; else rp->red_thmax = th_max; rp->red_flags = flags; if (pkttime == 0) /* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */ rp->red_pkttime = 800; else rp->red_pkttime = pkttime; if (weight == 0) { /* when the link is very slow, adjust red parameters */ npkts_per_sec = 1000000 / rp->red_pkttime; if (npkts_per_sec < 50) { /* up to about 400Kbps */ rp->red_weight = W_WEIGHT_2; } else if (npkts_per_sec < 300) { /* up to about 2.4Mbps */ rp->red_weight = W_WEIGHT_1; } } /* calculate wshift. weight must be power of 2 */ w = rp->red_weight; for (i = 0; w > 1; i++) w = w >> 1; rp->red_wshift = i; w = 1 << rp->red_wshift; if (w != rp->red_weight) { printf("invalid weight value %d for red! use %d\n", rp->red_weight, w); rp->red_weight = w; } /* * thmin_s and thmax_s are scaled versions of th_min and th_max * to be compared with avg. */ rp->red_thmin_s = rp->red_thmin << (rp->red_wshift + FP_SHIFT); rp->red_thmax_s = rp->red_thmax << (rp->red_wshift + FP_SHIFT); /* * precompute probability denominator * probd = (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point */ rp->red_probd = (2 * (rp->red_thmax - rp->red_thmin) * rp->red_inv_pmax) << FP_SHIFT; /* allocate weight table */ rp->red_wtab = wtab_alloc(rp->red_weight); microtime(&rp->red_last); #ifdef ALTQ_FLOWVALVE if (flags & REDF_FLOWVALVE) rp->red_flowvalve = fv_alloc(rp); /* if fv_alloc failes, flowvalve is just disabled */ #endif return (rp); } void red_destroy(rp) red_t *rp; { #ifdef ALTQ_FLOWVALVE if (rp->red_flowvalve != NULL) fv_destroy(rp->red_flowvalve); #endif wtab_destroy(rp->red_wtab); FREE(rp, M_DEVBUF); } void red_getstats(rp, sp) red_t *rp; struct redstats *sp; { sp->q_avg = rp->red_avg >> rp->red_wshift; sp->xmit_cnt = rp->red_stats.xmit_cnt; sp->drop_cnt = rp->red_stats.drop_cnt; sp->drop_forced = rp->red_stats.drop_forced; sp->drop_unforced = rp->red_stats.drop_unforced; sp->marked_packets = rp->red_stats.marked_packets; } /* * enqueue routine: * * returns: 0 when successfully queued. * ENOBUFS when drop occurs. */ static int red_enqueue(ifq, m, pktattr) struct ifaltq *ifq; struct mbuf *m; struct altq_pktattr *pktattr; { red_queue_t *rqp = (red_queue_t *)ifq->altq_disc; if (red_addq(rqp->rq_red, rqp->rq_q, m, pktattr) < 0) return ENOBUFS; ifq->ifq_len++; return 0; } int red_addq(rp, q, m, pktattr) red_t *rp; class_queue_t *q; struct mbuf *m; struct altq_pktattr *pktattr; { int avg, droptype; int n; #ifdef ALTQ_FLOWVALVE struct fve *fve = NULL; if (rp->red_flowvalve != NULL && rp->red_flowvalve->fv_flows > 0) if (fv_checkflow(rp->red_flowvalve, pktattr, &fve)) { m_freem(m); return (-1); } #endif avg = rp->red_avg; /* * if we were idle, we pretend that n packets arrived during * the idle period. */ if (rp->red_idle) { struct timeval now; int t; rp->red_idle = 0; microtime(&now); t = (now.tv_sec - rp->red_last.tv_sec); if (t > 60) { /* * being idle for more than 1 minute, set avg to zero. * this prevents t from overflow. */ avg = 0; } else { t = t * 1000000 + (now.tv_usec - rp->red_last.tv_usec); n = t / rp->red_pkttime - 1; /* the following line does (avg = (1 - Wq)^n * avg) */ if (n > 0) avg = (avg >> FP_SHIFT) * pow_w(rp->red_wtab, n); } } /* run estimator. (note: avg is scaled by WEIGHT in fixed-point) */ avg += (qlen(q) << FP_SHIFT) - (avg >> rp->red_wshift); rp->red_avg = avg; /* save the new value */ /* * red_count keeps a tally of arriving traffic that has not * been dropped. */ rp->red_count++; /* see if we drop early */ droptype = DTYPE_NODROP; if (avg >= rp->red_thmin_s && qlen(q) > 1) { if (avg >= rp->red_thmax_s) { /* avg >= th_max: forced drop */ droptype = DTYPE_FORCED; } else if (rp->red_old == 0) { /* first exceeds th_min */ rp->red_count = 1; rp->red_old = 1; } else if (drop_early((avg - rp->red_thmin_s) >> rp->red_wshift, rp->red_probd, rp->red_count)) { /* mark or drop by red */ if ((rp->red_flags & REDF_ECN) && mark_ecn(m, pktattr, rp->red_flags)) { /* successfully marked. do not drop. */ rp->red_count = 0; #ifdef RED_STATS rp->red_stats.marked_packets++; #endif } else { /* unforced drop by red */ droptype = DTYPE_EARLY; } } } else { /* avg < th_min */ rp->red_old = 0; } /* * if the queue length hits the hard limit, it's a forced drop. */ if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q)) droptype = DTYPE_FORCED; #ifdef RED_RANDOM_DROP /* if successful or forced drop, enqueue this packet. */ if (droptype != DTYPE_EARLY) _addq(q, m); #else /* if successful, enqueue this packet. */ if (droptype == DTYPE_NODROP) _addq(q, m); #endif if (droptype != DTYPE_NODROP) { if (droptype == DTYPE_EARLY) { /* drop the incoming packet */ #ifdef RED_STATS rp->red_stats.drop_unforced++; #endif } else { /* forced drop, select a victim packet in the queue. */ #ifdef RED_RANDOM_DROP m = _getq_random(q); #endif #ifdef RED_STATS rp->red_stats.drop_forced++; #endif } #ifdef RED_STATS PKTCNTR_ADD(&rp->red_stats.drop_cnt, m_pktlen(m)); #endif rp->red_count = 0; #ifdef ALTQ_FLOWVALVE if (rp->red_flowvalve != NULL) fv_dropbyred(rp->red_flowvalve, pktattr, fve); #endif m_freem(m); return (-1); } /* successfully queued */ #ifdef RED_STATS PKTCNTR_ADD(&rp->red_stats.xmit_cnt, m_pktlen(m)); #endif return (0); } /* * early-drop probability is calculated as follows: * prob = p_max * (avg - th_min) / (th_max - th_min) * prob_a = prob / (2 - count*prob) * = (avg-th_min) / (2*(th_max-th_min)*inv_p_max - count*(avg-th_min)) * here prob_a increases as successive undrop count increases. * (prob_a starts from prob/2, becomes prob when (count == (1 / prob)), * becomes 1 when (count >= (2 / prob))). */ int drop_early(fp_len, fp_probd, count) int fp_len; /* (avg - TH_MIN) in fixed-point */ int fp_probd; /* (2 * (TH_MAX-TH_MIN) / pmax) in fixed-point */ int count; /* how many successive undropped packets */ { int d; /* denominator of drop-probability */ d = fp_probd - count * fp_len; if (d <= 0) /* count exceeds the hard limit: drop or mark */ return (1); /* * now the range of d is [1..600] in fixed-point. (when * th_max-th_min=10 and p_max=1/30) * drop probability = (avg - TH_MIN) / d */ if ((random() % d) < fp_len) { /* drop or mark */ return (1); } /* no drop/mark */ return (0); } /* * try to mark CE bit to the packet. * returns 1 if successfully marked, 0 otherwise. */ int mark_ecn(m, pktattr, flags) struct mbuf *m; struct altq_pktattr *pktattr; int flags; { struct mbuf *m0; if (pktattr == NULL || (pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6)) return (0); /* verify that pattr_hdr is within the mbuf data */ for (m0 = m; m0 != NULL; m0 = m0->m_next) if ((pktattr->pattr_hdr >= m0->m_data) && (pktattr->pattr_hdr < m0->m_data + m0->m_len)) break; if (m0 == NULL) { /* ick, pattr_hdr is stale */ pktattr->pattr_af = AF_UNSPEC; return (0); } switch (pktattr->pattr_af) { case AF_INET: if (flags & REDF_ECN4) { struct ip *ip = (struct ip *)pktattr->pattr_hdr; if (ip->ip_v != 4) return (0); /* version mismatch! */ if (ip->ip_tos & IPTOS_ECT) { /* ECN-capable, mark ECN bit. */ if ((ip->ip_tos & IPTOS_CE) == 0) { #if (IPTOS_CE == 0x01) u_short sum; ip->ip_tos |= IPTOS_CE; /* * optimized version when IPTOS_CE * is 0x01. * HC' = HC -1 when HC > 0 * = 0xfffe when HC = 0 */ sum = ntohs(ip->ip_sum); if (sum == 0) sum = 0xfffe; else sum -= 1; ip->ip_sum = htons(sum); #else /* IPTOS_CE != 0x01 */ long sum; ip->ip_tos |= IPTOS_CE; /* * update checksum (from RFC1624) * HC' = ~(~HC + ~m + m') */ sum = ~ntohs(ip->ip_sum) & 0xffff; sum += 0xffff + IPTOS_CE; sum = (sum >> 16) + (sum & 0xffff); sum += (sum >> 16); /* add carry */ ip->ip_sum = htons(~sum & 0xffff); #endif /* IPTOS_CE != 0x01 */ } return (1); } } break; #ifdef INET6 case AF_INET6: if (flags & REDF_ECN6) { struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr; u_int32_t flowlabel; flowlabel = ntohl(ip6->ip6_flow); if ((flowlabel >> 28) != 6) return (0); /* version mismatch! */ if (flowlabel & (IPTOS_ECT << 20)) { /* ECN-capable, mark ECN bit. */ flowlabel |= (IPTOS_CE << 20); ip6->ip6_flow = htonl(flowlabel); return (1); } } break; #endif /* INET6 */ } /* not marked */ return (0); } /* * dequeue routine: * must be called in splimp. * * returns: mbuf dequeued. * NULL when no packet is available in the queue. */ static struct mbuf * red_dequeue(ifq, op) struct ifaltq *ifq; int op; { red_queue_t *rqp = (red_queue_t *)ifq->altq_disc; struct mbuf *m; if (op == ALTDQ_POLL) return qhead(rqp->rq_q); /* op == ALTDQ_REMOVE */ m = red_getq(rqp->rq_red, rqp->rq_q); if (m != NULL) ifq->ifq_len--; return (m); } struct mbuf * red_getq(rp, q) red_t *rp; class_queue_t *q; { struct mbuf *m; if ((m = _getq(q)) == NULL) { if (rp->red_idle == 0) { rp->red_idle = 1; microtime(&rp->red_last); } return NULL; } rp->red_idle = 0; return (m); } static int red_request(ifq, req, arg) struct ifaltq *ifq; int req; void *arg; { red_queue_t *rqp = (red_queue_t *)ifq->altq_disc; switch (req) { case ALTRQ_PURGE: red_purgeq(rqp); break; } return (0); } static void red_purgeq(rqp) red_queue_t *rqp; { _flushq(rqp->rq_q); if (ALTQ_IS_ENABLED(rqp->rq_ifq)) rqp->rq_ifq->ifq_len = 0; } /* * helper routine to calibrate avg during idle. * pow_w(wtab, n) returns (1 - Wq)^n in fixed-point * here Wq = 1/weight and the code assumes Wq is close to zero. * * w_tab[n] holds ((1 - Wq)^(2^n)) in fixed-point. */ static struct wtab *wtab_list = NULL; /* pointer to wtab list */ struct wtab * wtab_alloc(weight) int weight; { struct wtab *w; int i; for (w = wtab_list; w != NULL; w = w->w_next) if (w->w_weight == weight) { w->w_refcount++; return (w); } MALLOC(w, struct wtab *, sizeof(struct wtab), M_DEVBUF, M_WAITOK); if (w == NULL) panic("wtab_alloc: malloc failed!"); bzero(w, sizeof(struct wtab)); w->w_weight = weight; w->w_refcount = 1; w->w_next = wtab_list; wtab_list = w; /* initialize the weight table */ w->w_tab[0] = ((weight - 1) << FP_SHIFT) / weight; for (i = 1; i < 32; i++) { w->w_tab[i] = (w->w_tab[i-1] * w->w_tab[i-1]) >> FP_SHIFT; if (w->w_tab[i] == 0 && w->w_param_max == 0) w->w_param_max = 1 << i; } return (w); } int wtab_destroy(w) struct wtab *w; { struct wtab *prev; if (--w->w_refcount > 0) return (0); if (wtab_list == w) wtab_list = w->w_next; else for (prev = wtab_list; prev->w_next != NULL; prev = prev->w_next) if (prev->w_next == w) { prev->w_next = w->w_next; break; } FREE(w, M_DEVBUF); return (0); } int32_t pow_w(w, n) struct wtab *w; int n; { int i, bit; int32_t val; if (n >= w->w_param_max) return (0); val = 1 << FP_SHIFT; if (n <= 0) return (val); bit = 1; i = 0; while (n) { if (n & bit) { val = (val * w->w_tab[i]) >> FP_SHIFT; n &= ~bit; } i++; bit <<= 1; } return (val); } #ifdef ALTQ_FLOWVALVE #define FV_PSHIFT 7 /* weight of average drop rate -- 1/128 */ #define FV_PSCALE(x) ((x) << FV_PSHIFT) #define FV_PUNSCALE(x) ((x) >> FV_PSHIFT) #define FV_FSHIFT 5 /* weight of average fraction -- 1/32 */ #define FV_FSCALE(x) ((x) << FV_FSHIFT) #define FV_FUNSCALE(x) ((x) >> FV_FSHIFT) #define FV_TIMER (3 * hz) /* timer value for garbage collector */ #define FV_FLOWLISTSIZE 64 /* how many flows in flowlist */ #define FV_N 10 /* update fve_f every FV_N packets */ #define FV_BACKOFFTHRESH 1 /* backoff threshold interval in second */ #define FV_TTHRESH 3 /* time threshold to delete fve */ #define FV_ALPHA 5 /* extra packet count */ #define FV_STATS #if (__FreeBSD_version > 300000) #define FV_TIMESTAMP(tp) getmicrotime(tp) #else #define FV_TIMESTAMP(tp) { (*(tp)) = time; } #endif /* * Brtt table: 127 entry table to convert drop rate (p) to * the corresponding bandwidth fraction (f) * the following equation is implemented to use scaled values, * fve_p and fve_f, in the fixed point format. * * Brtt(p) = 1 /(sqrt(4*p/3) + min(1,3*sqrt(p*6/8)) * p * (1+32 * p*p)) * f = Brtt(p) / (max_th + alpha) */ #define BRTT_SIZE 128 #define BRTT_SHIFT 12 #define BRTT_MASK 0x0007f000 #define BRTT_PMAX (1 << (FV_PSHIFT + FP_SHIFT)) const int brtt_tab[BRTT_SIZE] = { 0, 1262010, 877019, 703694, 598706, 525854, 471107, 427728, 392026, 361788, 335598, 312506, 291850, 273158, 256081, 240361, 225800, 212247, 199585, 187788, 178388, 169544, 161207, 153333, 145888, 138841, 132165, 125836, 119834, 114141, 108739, 103612, 98747, 94129, 89746, 85585, 81637, 77889, 74333, 70957, 67752, 64711, 61824, 59084, 56482, 54013, 51667, 49440, 47325, 45315, 43406, 41591, 39866, 38227, 36667, 35184, 33773, 32430, 31151, 29933, 28774, 27668, 26615, 25611, 24653, 23740, 22868, 22035, 21240, 20481, 19755, 19062, 18399, 17764, 17157, 16576, 16020, 15487, 14976, 14487, 14017, 13567, 13136, 12721, 12323, 11941, 11574, 11222, 10883, 10557, 10243, 9942, 9652, 9372, 9103, 8844, 8594, 8354, 8122, 7898, 7682, 7474, 7273, 7079, 6892, 6711, 6536, 6367, 6204, 6046, 5893, 5746, 5603, 5464, 5330, 5201, 5075, 4954, 4836, 4722, 4611, 4504, 4400, 4299, 4201, 4106, 4014, 3924 }; static __inline struct fve * flowlist_lookup(fv, pktattr, now) struct flowvalve *fv; struct altq_pktattr *pktattr; struct timeval *now; { struct fve *fve; int flows; struct ip *ip; #ifdef INET6 struct ip6_hdr *ip6; #endif struct timeval tthresh; if (pktattr == NULL) return (NULL); tthresh.tv_sec = now->tv_sec - FV_TTHRESH; flows = 0; /* * search the flow list */ switch (pktattr->pattr_af) { case AF_INET: ip = (struct ip *)pktattr->pattr_hdr; TAILQ_FOREACH(fve, &fv->fv_flowlist, fve_lru){ if (fve->fve_lastdrop.tv_sec == 0) break; if (fve->fve_lastdrop.tv_sec < tthresh.tv_sec) { fve->fve_lastdrop.tv_sec = 0; break; } if (fve->fve_flow.flow_af == AF_INET && fve->fve_flow.flow_ip.ip_src.s_addr == ip->ip_src.s_addr && fve->fve_flow.flow_ip.ip_dst.s_addr == ip->ip_dst.s_addr) return (fve); flows++; } break; #ifdef INET6 case AF_INET6: ip6 = (struct ip6_hdr *)pktattr->pattr_hdr; TAILQ_FOREACH(fve, &fv->fv_flowlist, fve_lru){ if (fve->fve_lastdrop.tv_sec == 0) break; if (fve->fve_lastdrop.tv_sec < tthresh.tv_sec) { fve->fve_lastdrop.tv_sec = 0; break; } if (fve->fve_flow.flow_af == AF_INET6 && IN6_ARE_ADDR_EQUAL(&fve->fve_flow.flow_ip6.ip6_src, &ip6->ip6_src) && IN6_ARE_ADDR_EQUAL(&fve->fve_flow.flow_ip6.ip6_dst, &ip6->ip6_dst)) return (fve); flows++; } break; #endif /* INET6 */ default: /* unknown protocol. no drop. */ return (NULL); } fv->fv_flows = flows; /* save the number of active fve's */ return (NULL); } static __inline struct fve * flowlist_reclaim(fv, pktattr) struct flowvalve *fv; struct altq_pktattr *pktattr; { struct fve *fve; struct ip *ip; #ifdef INET6 struct ip6_hdr *ip6; #endif /* * get an entry from the tail of the LRU list. */ fve = TAILQ_LAST(&fv->fv_flowlist, fv_flowhead); switch (pktattr->pattr_af) { case AF_INET: ip = (struct ip *)pktattr->pattr_hdr; fve->fve_flow.flow_af = AF_INET; fve->fve_flow.flow_ip.ip_src = ip->ip_src; fve->fve_flow.flow_ip.ip_dst = ip->ip_dst; break; #ifdef INET6 case AF_INET6: ip6 = (struct ip6_hdr *)pktattr->pattr_hdr; fve->fve_flow.flow_af = AF_INET6; fve->fve_flow.flow_ip6.ip6_src = ip6->ip6_src; fve->fve_flow.flow_ip6.ip6_dst = ip6->ip6_dst; break; #endif } fve->fve_state = Green; fve->fve_p = 0.0; fve->fve_f = 0.0; fve->fve_ifseq = fv->fv_ifseq - 1; fve->fve_count = 0; fv->fv_flows++; #ifdef FV_STATS fv->fv_stats.alloc++; #endif return (fve); } static __inline void flowlist_move_to_head(fv, fve) struct flowvalve *fv; struct fve *fve; { if (TAILQ_FIRST(&fv->fv_flowlist) != fve) { TAILQ_REMOVE(&fv->fv_flowlist, fve, fve_lru); TAILQ_INSERT_HEAD(&fv->fv_flowlist, fve, fve_lru); } } /* * allocate flowvalve structure */ static struct flowvalve * fv_alloc(rp) struct red *rp; { struct flowvalve *fv; struct fve *fve; int i, num; num = FV_FLOWLISTSIZE; MALLOC(fv, struct flowvalve *, sizeof(struct flowvalve), M_DEVBUF, M_WAITOK); if (fv == NULL) return (NULL); bzero(fv, sizeof(struct flowvalve)); MALLOC(fv->fv_fves, struct fve *, sizeof(struct fve) * num, M_DEVBUF, M_WAITOK); if (fv->fv_fves == NULL) { FREE(fv, M_DEVBUF); return (NULL); } bzero(fv->fv_fves, sizeof(struct fve) * num); fv->fv_flows = 0; TAILQ_INIT(&fv->fv_flowlist); for (i = 0; i < num; i++) { fve = &fv->fv_fves[i]; fve->fve_lastdrop.tv_sec = 0; TAILQ_INSERT_TAIL(&fv->fv_flowlist, fve, fve_lru); } /* initialize drop rate threshold in scaled fixed-point */ fv->fv_pthresh = (FV_PSCALE(1) << FP_SHIFT) / rp->red_inv_pmax; /* initialize drop rate to fraction table */ MALLOC(fv->fv_p2ftab, int *, sizeof(int) * BRTT_SIZE, M_DEVBUF, M_WAITOK); if (fv->fv_p2ftab == NULL) { FREE(fv->fv_fves, M_DEVBUF); FREE(fv, M_DEVBUF); return (NULL); } /* * create the p2f table. * (shift is used to keep the precision) */ for (i = 1; i < BRTT_SIZE; i++) { int f; f = brtt_tab[i] << 8; fv->fv_p2ftab[i] = (f / (rp->red_thmax + FV_ALPHA)) >> 8; } return (fv); } static void fv_destroy(fv) struct flowvalve *fv; { FREE(fv->fv_p2ftab, M_DEVBUF); FREE(fv->fv_fves, M_DEVBUF); FREE(fv, M_DEVBUF); } static __inline int fv_p2f(fv, p) struct flowvalve *fv; int p; { int val, f; if (p >= BRTT_PMAX) f = fv->fv_p2ftab[BRTT_SIZE-1]; else if ((val = (p & BRTT_MASK))) f = fv->fv_p2ftab[(val >> BRTT_SHIFT)]; else f = fv->fv_p2ftab[1]; return (f); } /* * check if an arriving packet should be pre-dropped. * called from red_addq() when a packet arrives. * returns 1 when the packet should be pre-dropped. * should be called in splimp. */ static int fv_checkflow(fv, pktattr, fcache) struct flowvalve *fv; struct altq_pktattr *pktattr; struct fve **fcache; { struct fve *fve; struct timeval now; fv->fv_ifseq++; FV_TIMESTAMP(&now); if ((fve = flowlist_lookup(fv, pktattr, &now)) == NULL) /* no matching entry in the flowlist */ return (0); *fcache = fve; /* update fraction f for every FV_N packets */ if (++fve->fve_count == FV_N) { /* * f = Wf * N / (fv_ifseq - fve_ifseq) + (1 - Wf) * f */ fve->fve_f = (FV_N << FP_SHIFT) / (fv->fv_ifseq - fve->fve_ifseq) + fve->fve_f - FV_FUNSCALE(fve->fve_f); fve->fve_ifseq = fv->fv_ifseq; fve->fve_count = 0; } /* * overpumping test */ if (fve->fve_state == Green && fve->fve_p > fv->fv_pthresh) { int fthresh; /* calculate a threshold */ fthresh = fv_p2f(fv, fve->fve_p); if (fve->fve_f > fthresh) fve->fve_state = Red; } if (fve->fve_state == Red) { /* * backoff test */ if (now.tv_sec - fve->fve_lastdrop.tv_sec > FV_BACKOFFTHRESH) { /* no drop for at least FV_BACKOFFTHRESH sec */ fve->fve_p = 0; fve->fve_state = Green; #ifdef FV_STATS fv->fv_stats.escape++; #endif } else { /* block this flow */ flowlist_move_to_head(fv, fve); fve->fve_lastdrop = now; #ifdef FV_STATS fv->fv_stats.predrop++; #endif return (1); } } /* * p = (1 - Wp) * p */ fve->fve_p -= FV_PUNSCALE(fve->fve_p); if (fve->fve_p < 0) fve->fve_p = 0; #ifdef FV_STATS fv->fv_stats.pass++; #endif return (0); } /* * called from red_addq when a packet is dropped by red. * should be called in splimp. */ static void fv_dropbyred(fv, pktattr, fcache) struct flowvalve *fv; struct altq_pktattr *pktattr; struct fve *fcache; { struct fve *fve; struct timeval now; if (pktattr == NULL) return; FV_TIMESTAMP(&now); if (fcache != NULL) /* the fve of this packet is already cached */ fve = fcache; else if ((fve = flowlist_lookup(fv, pktattr, &now)) == NULL) fve = flowlist_reclaim(fv, pktattr); flowlist_move_to_head(fv, fve); /* * update p: the following line cancels the update * in fv_checkflow() and calculate * p = Wp + (1 - Wp) * p */ fve->fve_p = (1 << FP_SHIFT) + fve->fve_p; fve->fve_lastdrop = now; } #endif /* ALTQ_FLOWVALVE */ #ifdef KLD_MODULE static struct altqsw red_sw = {"red", redopen, redclose, redioctl}; ALTQ_MODULE(altq_red, ALTQT_RED, &red_sw); #endif /* KLD_MODULE */