2 * Copyright (c) 2010 Luigi Rizzo, Riccardo Panicucci, Universita` di Pisa
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * Dummynet portions related to packet handling.
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD: user/luigi/ipfw3-head/sys/netinet/ipfw/ip_dn_io.c 203321 2010-01-31 21:39:25Z luigi $");
33 #include "opt_inet6.h"
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
39 #include <sys/kernel.h>
41 #include <sys/module.h>
44 #include <sys/rwlock.h>
45 #include <sys/socket.h>
47 #include <sys/sysctl.h>
48 #include <net/if.h> /* IFNAMSIZ, struct ifaddr, ifq head, lock.h mutex.h */
49 #include <net/netisr.h>
50 #include <netinet/in.h>
51 #include <netinet/ip.h> /* ip_len, ip_off */
52 #include <netinet/ip_var.h> /* ip_output(), IP_FORWARDING */
53 #include <netinet/ip_fw.h>
54 #include <netinet/ipfw/ip_fw_private.h>
55 #include <netinet/ipfw/dn_heap.h>
56 #include <netinet/ip_dummynet.h>
57 #include <netinet/ipfw/ip_dn_private.h>
58 #include <netinet/ipfw/dn_sched.h>
60 #include <netinet/if_ether.h> /* various ether_* routines */
62 #include <netinet/ip6.h> /* for ip6_input, ip6_output prototypes */
63 #include <netinet6/ip6_var.h>
66 * We keep a private variable for the simulation time, but we could
67 * probably use an existing one ("softticks" in sys/kern/kern_timeout.c)
68 * instead of dn_cfg.curr_time
71 struct dn_parms dn_cfg;
73 static long tick_last; /* Last tick duration (usec). */
74 static long tick_delta; /* Last vs standard tick diff (usec). */
75 static long tick_delta_sum; /* Accumulated tick difference (usec).*/
76 static long tick_adjustment; /* Tick adjustments done. */
77 static long tick_lost; /* Lost(coalesced) ticks number. */
78 /* Adjusted vs non-adjusted curr_time difference (ticks). */
79 static long tick_diff;
81 static unsigned long io_pkt;
82 static unsigned long io_pkt_fast;
83 static unsigned long io_pkt_drop;
86 * We use a heap to store entities for which we have pending timer events.
87 * The heap is checked at every tick and all entities with expired events
91 MALLOC_DEFINE(M_DUMMYNET, "dummynet", "dummynet heap");
93 extern void (*bridge_dn_p)(struct mbuf *, struct ifnet *);
99 SYSCTL_DECL(_net_inet);
100 SYSCTL_DECL(_net_inet_ip);
101 SYSCTL_NODE(_net_inet_ip, OID_AUTO, dummynet, CTLFLAG_RW, 0, "Dummynet");
104 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, hash_size,
105 CTLFLAG_RW, &dn_cfg.hash_size, 0, "Default hash table size");
106 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_slot_limit,
107 CTLFLAG_RW, &dn_cfg.slot_limit, 0,
108 "Upper limit in slots for pipe queue.");
109 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, pipe_byte_limit,
110 CTLFLAG_RW, &dn_cfg.byte_limit, 0,
111 "Upper limit in bytes for pipe queue.");
112 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, io_fast,
113 CTLFLAG_RW, &dn_cfg.io_fast, 0, "Enable fast dummynet io.");
114 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, debug,
115 CTLFLAG_RW, &dn_cfg.debug, 0, "Dummynet debug level");
116 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, expire,
117 CTLFLAG_RW, &dn_cfg.expire, 0, "Expire empty queues/pipes");
118 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, expire_cycle,
119 CTLFLAG_RD, &dn_cfg.expire_cycle, 0, "Expire cycle for queues/pipes");
122 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_lookup_depth,
123 CTLFLAG_RD, &dn_cfg.red_lookup_depth, 0, "Depth of RED lookup table");
124 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_avg_pkt_size,
125 CTLFLAG_RD, &dn_cfg.red_avg_pkt_size, 0, "RED Medium packet size");
126 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, red_max_pkt_size,
127 CTLFLAG_RD, &dn_cfg.red_max_pkt_size, 0, "RED Max packet size");
129 /* time adjustment */
130 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_delta,
131 CTLFLAG_RD, &tick_delta, 0, "Last vs standard tick difference (usec).");
132 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_delta_sum,
133 CTLFLAG_RD, &tick_delta_sum, 0, "Accumulated tick difference (usec).");
134 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_adjustment,
135 CTLFLAG_RD, &tick_adjustment, 0, "Tick adjustments done.");
136 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_diff,
137 CTLFLAG_RD, &tick_diff, 0,
138 "Adjusted vs non-adjusted curr_time difference (ticks).");
139 SYSCTL_LONG(_net_inet_ip_dummynet, OID_AUTO, tick_lost,
140 CTLFLAG_RD, &tick_lost, 0,
141 "Number of ticks coalesced by dummynet taskqueue.");
144 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, schk_count,
145 CTLFLAG_RD, &dn_cfg.schk_count, 0, "Number of schedulers");
146 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, si_count,
147 CTLFLAG_RD, &dn_cfg.si_count, 0, "Number of scheduler instances");
148 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, fsk_count,
149 CTLFLAG_RD, &dn_cfg.fsk_count, 0, "Number of flowsets");
150 SYSCTL_INT(_net_inet_ip_dummynet, OID_AUTO, queue_count,
151 CTLFLAG_RD, &dn_cfg.queue_count, 0, "Number of queues");
152 SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt,
153 CTLFLAG_RD, &io_pkt, 0,
154 "Number of packets passed to dummynet.");
155 SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_fast,
156 CTLFLAG_RD, &io_pkt_fast, 0,
157 "Number of packets bypassed dummynet scheduler.");
158 SYSCTL_ULONG(_net_inet_ip_dummynet, OID_AUTO, io_pkt_drop,
159 CTLFLAG_RD, &io_pkt_drop, 0,
160 "Number of packets dropped by dummynet.");
166 static void dummynet_send(struct mbuf *);
169 * Packets processed by dummynet have an mbuf tag associated with
170 * them that carries their dummynet state.
171 * Outside dummynet, only the 'rule' field is relevant, and it must
172 * be at the beginning of the structure.
175 struct ipfw_rule_ref rule; /* matching rule */
177 /* second part, dummynet specific */
178 int dn_dir; /* action when packet comes out.*/
179 /* see ip_fw_private.h */
180 uint64_t output_time; /* when the pkt is due for delivery*/
181 struct ifnet *ifp; /* interface, for ip_output */
182 struct _ip6dn_args ip6opt; /* XXX ipv6 options */
186 * Return the mbuf tag holding the dummynet state (it should
187 * be the first one on the list).
189 static struct dn_pkt_tag *
190 dn_tag_get(struct mbuf *m)
192 struct m_tag *mtag = m_tag_first(m);
193 KASSERT(mtag != NULL &&
194 mtag->m_tag_cookie == MTAG_ABI_COMPAT &&
195 mtag->m_tag_id == PACKET_TAG_DUMMYNET,
196 ("packet on dummynet queue w/o dummynet tag!"));
197 return (struct dn_pkt_tag *)(mtag+1);
201 mq_append(struct mq *q, struct mbuf *m)
206 q->tail->m_nextpkt = m;
212 * Dispose a list of packet. Use a functions so if we need to do
213 * more work, this is a central point to do it.
215 void dn_free_pkts(struct mbuf *mnext)
219 while ((m = mnext) != NULL) {
220 mnext = m->m_nextpkt;
226 red_drops (struct dn_queue *q, int len)
231 * RED calculates the average queue size (avg) using a low-pass filter
232 * with an exponential weighted (w_q) moving average:
233 * avg <- (1-w_q) * avg + w_q * q_size
234 * where q_size is the queue length (measured in bytes or * packets).
236 * If q_size == 0, we compute the idle time for the link, and set
237 * avg = (1 - w_q)^(idle/s)
238 * where s is the time needed for transmitting a medium-sized packet.
240 * Now, if avg < min_th the packet is enqueued.
241 * If avg > max_th the packet is dropped. Otherwise, the packet is
242 * dropped with probability P function of avg.
245 struct dn_fsk *fs = q->fs;
248 /* Queue in bytes or packets? */
249 uint32_t q_size = (fs->fs.flags & DN_QSIZE_BYTES) ?
250 q->ni.len_bytes : q->ni.length;
252 /* Average queue size estimation. */
254 /* Queue is not empty, avg <- avg + (q_size - avg) * w_q */
255 int diff = SCALE(q_size) - q->avg;
256 int64_t v = SCALE_MUL((int64_t)diff, (int64_t)fs->w_q);
261 * Queue is empty, find for how long the queue has been
262 * empty and use a lookup table for computing
263 * (1 - * w_q)^(idle_time/s) where s is the time to send a
268 u_int t = div64((dn_cfg.curr_time - q->q_time), fs->lookup_step);
270 q->avg = (t < fs->lookup_depth) ?
271 SCALE_MUL(q->avg, fs->w_q_lookup[t]) : 0;
276 if (q->avg < fs->min_th) {
278 return (0); /* accept packet */
280 if (q->avg >= fs->max_th) { /* average queue >= max threshold */
281 if (fs->fs.flags & DN_IS_GENTLE_RED) {
283 * According to Gentle-RED, if avg is greater than
284 * max_th the packet is dropped with a probability
285 * p_b = c_3 * avg - c_4
286 * where c_3 = (1 - max_p) / max_th
287 * c_4 = 1 - 2 * max_p
289 p_b = SCALE_MUL((int64_t)fs->c_3, (int64_t)q->avg) -
295 } else if (q->avg > fs->min_th) {
297 * We compute p_b using the linear dropping function
298 * p_b = c_1 * avg - c_2
299 * where c_1 = max_p / (max_th - min_th)
300 * c_2 = max_p * min_th / (max_th - min_th)
302 p_b = SCALE_MUL((int64_t)fs->c_1, (int64_t)q->avg) - fs->c_2;
305 if (fs->fs.flags & DN_QSIZE_BYTES)
306 p_b = div64((p_b * len) , fs->max_pkt_size);
308 q->random = random() & 0xffff;
311 * q->count counts packets arrived since last drop, so a greater
312 * value of q->count means a greater packet drop probability.
314 if (SCALE_MUL(p_b, SCALE((int64_t)q->count)) > q->random) {
316 /* After a drop we calculate a new random value. */
317 q->random = random() & 0xffff;
318 return (1); /* drop */
321 /* End of RED algorithm. */
323 return (0); /* accept */
328 * Enqueue a packet in q, subject to space and queue management policy
329 * (whose parameters are in q->fs).
330 * Update stats for the queue and the scheduler.
331 * Return 0 on success, 1 on drop. The packet is consumed anyways.
334 dn_enqueue(struct dn_queue *q, struct mbuf* m, int drop)
337 struct dn_flow *ni; /* stats for scheduler instance */
340 if (q->fs == NULL || q->_si == NULL) {
341 printf("%s fs %p si %p, dropping\n",
342 __FUNCTION__, q->fs, q->_si);
348 len = m->m_pkthdr.len;
349 /* Update statistics, then check reasons to drop pkt. */
350 q->ni.tot_bytes += len;
352 ni->tot_bytes += len;
356 if (f->plr && random() < f->plr)
358 if (f->flags & DN_IS_RED && red_drops(q, m->m_pkthdr.len))
360 if (f->flags & DN_QSIZE_BYTES) {
361 if (q->ni.len_bytes > f->qsize)
363 } else if (q->ni.length >= f->qsize) {
366 mq_append(&q->mq, m);
368 q->ni.len_bytes += len;
370 ni->len_bytes += len;
382 * Fetch packets from the delay line which are due now. If there are
383 * leftover packets, reinsert the delay line in the heap.
384 * Runs under scheduler lock.
387 transmit_event(struct mq *q, struct delay_line *dline, uint64_t now)
390 struct dn_pkt_tag *pkt = NULL;
392 dline->oid.subtype = 0; /* not in heap */
393 while ((m = dline->mq.head) != NULL) {
395 if (!DN_KEY_LEQ(pkt->output_time, now))
397 dline->mq.head = m->m_nextpkt;
401 dline->oid.subtype = 1; /* in heap */
402 heap_insert(&dn_cfg.evheap, pkt->output_time, dline);
407 * Convert the additional MAC overheads/delays into an equivalent
408 * number of bits for the given data rate. The samples are
409 * in milliseconds so we need to divide by 1000.
412 extra_bits(struct mbuf *m, struct dn_schk *s)
416 struct dn_profile *pf = s->profile;
418 if (!pf || pf->samples_no == 0)
420 index = random() % pf->samples_no;
421 bits = div64((uint64_t)pf->samples[index] * s->link.bandwidth, 1000);
422 if (index >= pf->loss_level) {
423 struct dn_pkt_tag *dt = dn_tag_get(m);
425 dt->dn_dir = DIR_DROP;
431 * Send traffic from a scheduler instance due by 'now'.
432 * Return a pointer to the head of the queue.
435 serve_sched(struct mq *q, struct dn_sch_inst *si, uint64_t now)
438 struct dn_schk *s = si->sched;
439 struct mbuf *m = NULL;
440 int delay_line_idle = (si->dline.mq.head == NULL);
448 bw = s->link.bandwidth;
449 si->kflags &= ~DN_ACTIVE;
452 si->credit += (now - si->sched_time) * bw;
455 si->sched_time = now;
457 while (si->credit >= 0 && (m = s->fp->dequeue(si)) != NULL) {
458 if (m->m_pkthdr.len < 0) {
459 /* Received a packet with negative length.
460 * the scheduler instance will be waken up after
461 * -m->m_pkthdr.len ticks.
463 si->kflags |= DN_ACTIVE;
464 heap_insert(&dn_cfg.evheap, now - m->m_pkthdr.len, si);
466 /* Delete the fake packet */
469 /* Dont' touch credit, exit from the function */
471 } else { /* normal behaviour */
474 len_scaled = (bw == 0) ? 0 : hz *
475 (m->m_pkthdr.len * 8 + extra_bits(m, s));
476 si->credit -= len_scaled;
477 /* Move packet in the delay line */
478 dn_tag_get(m)->output_time += s->link.delay ;
479 mq_append(&si->dline.mq, m);
483 * If credit >= 0 the instance is idle, mark time.
484 * Otherwise put back in the heap, and adjust the output
485 * time of the last inserted packet, m, which was too early.
487 if (si->credit >= 0) {
491 KASSERT (bw > 0, ("bw=0 and credit<0 ?"));
492 t = div64(bw - 1 - si->credit, bw);
494 dn_tag_get(m)->output_time += t;
495 si->kflags |= DN_ACTIVE;
496 heap_insert(&dn_cfg.evheap, now + t, si);
498 if (delay_line_idle && done)
499 transmit_event(q, &si->dline, now);
504 * The timer handler for dummynet. Time is computed in ticks, but
505 * but the code is tolerant to the actual rate at which this is called.
506 * Once complete, the function reschedules itself for the next tick.
509 dummynet_task(void *context, int pending)
512 struct mq q = { NULL, NULL }; /* queue to accumulate results */
516 /* Update number of lost(coalesced) ticks. */
517 tick_lost += pending - 1;
520 /* Last tick duration (usec). */
521 tick_last = (t.tv_sec - dn_cfg.prev_t.tv_sec) * 1000000 +
522 (t.tv_usec - dn_cfg.prev_t.tv_usec);
523 /* Last tick vs standard tick difference (usec). */
524 tick_delta = (tick_last * hz - 1000000) / hz;
525 /* Accumulated tick difference (usec). */
526 tick_delta_sum += tick_delta;
531 * Adjust curr_time if the accumulated tick difference is
532 * greater than the 'standard' tick. Since curr_time should
533 * be monotonically increasing, we do positive adjustments
534 * as required, and throttle curr_time in case of negative
538 if (tick_delta_sum - tick >= 0) {
539 int diff = tick_delta_sum / tick;
541 dn_cfg.curr_time += diff;
543 tick_delta_sum %= tick;
545 } else if (tick_delta_sum + tick <= 0) {
548 tick_delta_sum += tick;
552 /* serve pending events, accumulate in q */
554 struct dn_id *p; /* generic parameter to handler */
556 if (dn_cfg.evheap.elements == 0 ||
557 DN_KEY_LT(dn_cfg.curr_time, HEAP_TOP(&dn_cfg.evheap)->key))
559 p = HEAP_TOP(&dn_cfg.evheap)->object;
560 heap_extract(&dn_cfg.evheap, NULL);
562 if (p->type == DN_SCH_I) {
563 serve_sched(&q, (struct dn_sch_inst *)p, dn_cfg.curr_time);
564 } else { /* extracted a delay line */
565 transmit_event(&q, (struct delay_line *)p, dn_cfg.curr_time);
568 if (dn_cfg.expire && ++dn_cfg.expire_cycle >= dn_cfg.expire) {
569 dn_cfg.expire_cycle = 0;
570 dn_drain_scheduler();
577 dummynet_send(q.head);
581 * forward a chain of packets to the proper destination.
582 * This runs outside the dummynet lock.
585 dummynet_send(struct mbuf *m)
589 for (; m != NULL; m = n) {
590 struct ifnet *ifp = NULL; /* gcc 3.4.6 complains */
596 tag = m_tag_first(m);
597 if (tag == NULL) { /* should not happen */
600 struct dn_pkt_tag *pkt = dn_tag_get(m);
601 /* extract the dummynet info, rename the tag
602 * to carry reinject info.
606 tag->m_tag_cookie = MTAG_IPFW_RULE;
612 SET_HOST_IPLEN(mtod(m, struct ip *));
613 ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
617 /* put header in network format for ip_input() */
618 //SET_NET_IPLEN(mtod(m, struct ip *));
619 netisr_dispatch(NETISR_IP, m);
623 case DIR_IN | PROTO_IPV6:
624 netisr_dispatch(NETISR_IPV6, m);
627 case DIR_OUT | PROTO_IPV6:
628 SET_HOST_IPLEN(mtod(m, struct ip *));
629 ip6_output(m, NULL, NULL, IPV6_FORWARDING, NULL, NULL, NULL);
633 case DIR_FWD | PROTO_IFB: /* DN_TO_IFB_FWD: */
634 if (bridge_dn_p != NULL)
635 ((*bridge_dn_p)(m, ifp));
637 printf("dummynet: if_bridge not loaded\n");
641 case DIR_IN | PROTO_LAYER2: /* DN_TO_ETH_DEMUX: */
643 * The Ethernet code assumes the Ethernet header is
644 * contiguous in the first mbuf header.
645 * Insure this is true.
647 if (m->m_len < ETHER_HDR_LEN &&
648 (m = m_pullup(m, ETHER_HDR_LEN)) == NULL) {
649 printf("dummynet/ether: pullup failed, "
650 "dropping packet\n");
653 ether_demux(m->m_pkthdr.rcvif, m);
656 case DIR_OUT | PROTO_LAYER2: /* N_TO_ETH_OUT: */
657 ether_output_frame(ifp, m);
661 /* drop the packet after some time */
666 printf("dummynet: bad switch %d!\n", dst);
674 tag_mbuf(struct mbuf *m, int dir, struct ip_fw_args *fwa)
676 struct dn_pkt_tag *dt;
679 mtag = m_tag_get(PACKET_TAG_DUMMYNET,
680 sizeof(*dt), M_NOWAIT | M_ZERO);
682 return 1; /* Cannot allocate packet header. */
683 m_tag_prepend(m, mtag); /* Attach to mbuf chain. */
684 dt = (struct dn_pkt_tag *)(mtag + 1);
685 dt->rule = fwa->rule;
686 dt->rule.info &= IPFW_ONEPASS; /* only keep this info */
689 /* dt->output tame is updated as we move through */
690 dt->output_time = dn_cfg.curr_time;
696 * dummynet hook for packets.
697 * We use the argument to locate the flowset fs and the sched_set sch
698 * associated to it. The we apply flow_mask and sched_mask to
699 * determine the queue and scheduler instances.
701 * dir where shall we send the packet after dummynet.
702 * *m0 the mbuf with the packet
703 * ifp the 'ifp' parameter from the caller.
704 * NULL in ip_input, destination interface in ip_output,
707 dummynet_io(struct mbuf **m0, int dir, struct ip_fw_args *fwa)
709 struct mbuf *m = *m0;
710 struct dn_fsk *fs = NULL;
711 struct dn_sch_inst *si;
712 struct dn_queue *q = NULL; /* default */
714 int fs_id = (fwa->rule.info & IPFW_INFO_MASK) +
715 ((fwa->rule.info & IPFW_IS_PIPE) ? 2*DN_MAX_ID : 0);
718 /* we could actually tag outside the lock, but who cares... */
719 if (tag_mbuf(m, dir, fwa))
722 /* if the upper half is busy doing something expensive,
723 * lets queue the packet and move forward
725 mq_append(&dn_cfg.pending, m);
726 m = *m0 = NULL; /* consumed */
727 goto done; /* already active, nothing to do */
729 /* XXX locate_flowset could be optimised with a direct ref. */
730 fs = dn_ht_find(dn_cfg.fshash, fs_id, 0, NULL);
732 goto dropit; /* This queue/pipe does not exist! */
733 if (fs->sched == NULL) /* should not happen */
735 /* find scheduler instance, possibly applying sched_mask */
736 si = ipdn_si_find(fs->sched, &(fwa->f_id));
740 * If the scheduler supports multiple queues, find the right one
741 * (otherwise it will be ignored by enqueue).
743 if (fs->sched->fp->flags & DN_MULTIQUEUE) {
744 q = ipdn_q_find(fs, si, &(fwa->f_id));
748 if (fs->sched->fp->enqueue(si, q, m)) {
749 printf("%s dropped by enqueue\n", __FUNCTION__);
750 /* packet was dropped by enqueue() */
755 if (si->kflags & DN_ACTIVE) {
756 m = *m0 = NULL; /* consumed */
757 goto done; /* already active, nothing to do */
760 /* compute the initial allowance */
762 struct dn_link *p = &fs->sched->link;
763 si->credit = dn_cfg.io_fast ? p->bandwidth : 0;
765 uint64_t burst = (dn_cfg.curr_time - si->idle_time) * p->bandwidth;
766 if (burst > p->burst)
771 /* pass through scheduler and delay line */
772 m = serve_sched(NULL, si, dn_cfg.curr_time);
774 /* optimization -- pass it back to ipfw for immediate send */
775 /* XXX Don't call dummynet_send() if scheduler return the packet
776 * just enqueued. This avoid a lock order reversal.
779 if (/*dn_cfg.io_fast &&*/ m == *m0 && (dir & PROTO_LAYER2) == 0 ) {
780 /* fast io, rename the tag * to carry reinject info. */
781 struct m_tag *tag = m_tag_first(m);
783 tag->m_tag_cookie = MTAG_IPFW_RULE;
786 if (m->m_nextpkt != NULL) {
787 printf("dummynet: fast io: pkt chain detected!\n");
806 return (fs && (fs->fs.flags & DN_NOERROR)) ? 0 : ENOBUFS;