xref: /freebsd/sys/netgraph/ng_source.c (revision e1fe3dba5ce2826061f6489765be9b4a341736a9)
1 /*
2  * ng_source.c
3  */
4 
5 /*-
6  * Copyright (c) 2005 Gleb Smirnoff <glebius@FreeBSD.org>
7  * Copyright 2002 Sandvine Inc.
8  * All rights reserved.
9  *
10  * Subject to the following obligations and disclaimer of warranty, use and
11  * redistribution of this software, in source or object code forms, with or
12  * without modifications are expressly permitted by Sandvine Inc.; provided,
13  * however, that:
14  * 1. Any and all reproductions of the source or object code must include the
15  *    copyright notice above and the following disclaimer of warranties; and
16  * 2. No rights are granted, in any manner or form, to use Sandvine Inc.
17  *    trademarks, including the mark "SANDVINE" on advertising, endorsements,
18  *    or otherwise except as such appears in the above copyright notice or in
19  *    the software.
20  *
21  * THIS SOFTWARE IS BEING PROVIDED BY SANDVINE "AS IS", AND TO THE MAXIMUM
22  * EXTENT PERMITTED BY LAW, SANDVINE MAKES NO REPRESENTATIONS OR WARRANTIES,
23  * EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, INCLUDING WITHOUT LIMITATION,
24  * ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
25  * PURPOSE, OR NON-INFRINGEMENT.  SANDVINE DOES NOT WARRANT, GUARANTEE, OR
26  * MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE
27  * USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY
28  * OR OTHERWISE.  IN NO EVENT SHALL SANDVINE BE LIABLE FOR ANY DAMAGES
29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF SANDVINE IS ADVISED OF THE POSSIBILITY OF SUCH
36  * DAMAGE.
37  *
38  * Author: Dave Chapeskie <dchapeskie@sandvine.com>
39  */
40 
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 /*
45  * This node is used for high speed packet geneneration.  It queues
46  * all data recieved on its 'input' hook and when told to start via
47  * a control message it sends the packets out its 'output' hook.  In
48  * this way this node can be preloaded with a packet stream which it
49  * can then send continuously as fast as possible.
50  *
51  * Currently it just copies the mbufs as required.  It could do various
52  * tricks to try and avoid this.  Probably the best performance would
53  * be achieved by modifying the appropriate drivers to be told to
54  * self-re-enqueue packets (e.g. the if_bge driver could reuse the same
55  * transmit descriptors) under control of this node; perhaps via some
56  * flag in the mbuf or some such.  The node could peek at an appropriate
57  * ifnet flag to see if such support is available for the connected
58  * interface.
59  */
60 
61 #include <sys/param.h>
62 #include <sys/systm.h>
63 #include <sys/errno.h>
64 #include <sys/kernel.h>
65 #include <sys/malloc.h>
66 #include <sys/mbuf.h>
67 #include <sys/socket.h>
68 #include <sys/syslog.h>
69 #include <net/if.h>
70 #include <net/if_var.h>
71 #include <netgraph/ng_message.h>
72 #include <netgraph/netgraph.h>
73 #include <netgraph/ng_parse.h>
74 #include <netgraph/ng_ether.h>
75 #include <netgraph/ng_source.h>
76 
77 #define NG_SOURCE_INTR_TICKS		1
78 #define NG_SOURCE_DRIVER_IFQ_MAXLEN	(4*1024)
79 
80 /* Per node info */
81 struct privdata {
82 	node_p				node;
83 	hook_p				input;
84 	hook_p				output;
85 	struct ng_source_stats		stats;
86 	struct ifqueue			snd_queue;	/* packets to send */
87 	struct ifnet			*output_ifp;
88 	struct callout			intr_ch;
89 	uint64_t			packets;	/* packets to send */
90 	uint32_t			queueOctets;
91 };
92 typedef struct privdata *sc_p;
93 
94 /* Node flags */
95 #define NG_SOURCE_ACTIVE	(NGF_TYPE1)
96 
97 /* Netgraph methods */
98 static ng_constructor_t	ng_source_constructor;
99 static ng_rcvmsg_t	ng_source_rcvmsg;
100 static ng_shutdown_t	ng_source_rmnode;
101 static ng_newhook_t	ng_source_newhook;
102 static ng_connect_t	ng_source_connect;
103 static ng_rcvdata_t	ng_source_rcvdata;
104 static ng_disconnect_t	ng_source_disconnect;
105 
106 /* Other functions */
107 static void		ng_source_intr(node_p, hook_p, void *, int);
108 static void		ng_source_clr_data (sc_p);
109 static int		ng_source_start (sc_p, uint64_t);
110 static void		ng_source_stop (sc_p);
111 static int		ng_source_send (sc_p, int, int *);
112 static int		ng_source_store_output_ifp(sc_p, char *);
113 
114 /* Parse type for timeval */
115 static const struct ng_parse_struct_field ng_source_timeval_type_fields[] = {
116 	{ "tv_sec",		&ng_parse_int32_type	},
117 	{ "tv_usec",		&ng_parse_int32_type	},
118 	{ NULL }
119 };
120 const struct ng_parse_type ng_source_timeval_type = {
121 	&ng_parse_struct_type,
122 	&ng_source_timeval_type_fields
123 };
124 
125 /* Parse type for struct ng_source_stats */
126 static const struct ng_parse_struct_field ng_source_stats_type_fields[]
127 	= NG_SOURCE_STATS_TYPE_INFO;
128 static const struct ng_parse_type ng_source_stats_type = {
129 	&ng_parse_struct_type,
130 	&ng_source_stats_type_fields
131 };
132 
133 /* List of commands and how to convert arguments to/from ASCII */
134 static const struct ng_cmdlist ng_source_cmds[] = {
135 	{
136 	  NGM_SOURCE_COOKIE,
137 	  NGM_SOURCE_GET_STATS,
138 	  "getstats",
139 	  NULL,
140 	  &ng_source_stats_type
141 	},
142 	{
143 	  NGM_SOURCE_COOKIE,
144 	  NGM_SOURCE_CLR_STATS,
145 	  "clrstats",
146 	  NULL,
147 	  NULL
148 	},
149 	{
150 	  NGM_SOURCE_COOKIE,
151 	  NGM_SOURCE_GETCLR_STATS,
152 	  "getclrstats",
153 	  NULL,
154 	  &ng_source_stats_type
155 	},
156 	{
157 	  NGM_SOURCE_COOKIE,
158 	  NGM_SOURCE_START,
159 	  "start",
160 	  &ng_parse_uint64_type,
161 	  NULL
162 	},
163 	{
164 	  NGM_SOURCE_COOKIE,
165 	  NGM_SOURCE_STOP,
166 	  "stop",
167 	  NULL,
168 	  NULL
169 	},
170 	{
171 	  NGM_SOURCE_COOKIE,
172 	  NGM_SOURCE_CLR_DATA,
173 	  "clrdata",
174 	  NULL,
175 	  NULL
176 	},
177 	{
178 	  NGM_SOURCE_COOKIE,
179 	  NGM_SOURCE_SETIFACE,
180 	  "setiface",
181 	  &ng_parse_string_type,
182 	  NULL
183 	},
184 	{
185 	  NGM_SOURCE_COOKIE,
186 	  NGM_SOURCE_SETPPS,
187 	  "setpps",
188 	  &ng_parse_uint32_type,
189 	  NULL
190 	},
191 	{ 0 }
192 };
193 
194 /* Netgraph type descriptor */
195 static struct ng_type ng_source_typestruct = {
196 	.version =	NG_ABI_VERSION,
197 	.name =		NG_SOURCE_NODE_TYPE,
198 	.constructor =	ng_source_constructor,
199 	.rcvmsg =	ng_source_rcvmsg,
200 	.shutdown =	ng_source_rmnode,
201 	.newhook =	ng_source_newhook,
202 	.connect =	ng_source_connect,
203 	.rcvdata =	ng_source_rcvdata,
204 	.disconnect =	ng_source_disconnect,
205 	.cmdlist =	ng_source_cmds,
206 };
207 NETGRAPH_INIT(source, &ng_source_typestruct);
208 
209 static int ng_source_set_autosrc(sc_p, uint32_t);
210 
211 /*
212  * Node constructor
213  */
214 static int
215 ng_source_constructor(node_p node)
216 {
217 	sc_p sc;
218 
219 	sc = malloc(sizeof(*sc), M_NETGRAPH, M_NOWAIT | M_ZERO);
220 	if (sc == NULL)
221 		return (ENOMEM);
222 
223 	NG_NODE_SET_PRIVATE(node, sc);
224 	sc->node = node;
225 	sc->snd_queue.ifq_maxlen = 2048;	/* XXX not checked */
226 	ng_callout_init(&sc->intr_ch);
227 
228 	return (0);
229 }
230 
231 /*
232  * Add a hook
233  */
234 static int
235 ng_source_newhook(node_p node, hook_p hook, const char *name)
236 {
237 	sc_p sc = NG_NODE_PRIVATE(node);
238 
239 	if (strcmp(name, NG_SOURCE_HOOK_INPUT) == 0) {
240 		sc->input = hook;
241 	} else if (strcmp(name, NG_SOURCE_HOOK_OUTPUT) == 0) {
242 		sc->output = hook;
243 		sc->output_ifp = 0;
244 		bzero(&sc->stats, sizeof(sc->stats));
245 	} else
246 		return (EINVAL);
247 
248 	return (0);
249 }
250 
251 /*
252  * Hook has been added
253  */
254 static int
255 ng_source_connect(hook_p hook)
256 {
257 	sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
258 	struct ng_mesg *msg;
259 	int dummy_error = 0;
260 
261 	/*
262 	 * If this is "output" hook, then request information
263 	 * from our downstream.
264 	 */
265 	if (hook == sc->output) {
266 		NG_MKMESSAGE(msg, NGM_ETHER_COOKIE, NGM_ETHER_GET_IFNAME,
267 		    0, M_NOWAIT);
268 		if (msg == NULL)
269 			return (ENOBUFS);
270 
271 		/*
272 		 * Our hook and peer hook have HK_INVALID flag set,
273 		 * so we can't use NG_SEND_MSG_HOOK() macro here.
274 		 */
275 		NG_SEND_MSG_ID(dummy_error, sc->node, msg,
276 		    NG_NODE_ID(NG_PEER_NODE(sc->output)), NG_NODE_ID(sc->node));
277 	}
278 
279 	return (0);
280 }
281 
282 /*
283  * Receive a control message
284  */
285 static int
286 ng_source_rcvmsg(node_p node, item_p item, hook_p lasthook)
287 {
288 	sc_p sc = NG_NODE_PRIVATE(node);
289 	struct ng_mesg *msg, *resp = NULL;
290 	int error = 0;
291 
292 	NGI_GET_MSG(item, msg);
293 
294 	switch (msg->header.typecookie) {
295 	case NGM_SOURCE_COOKIE:
296 		if (msg->header.flags & NGF_RESP) {
297 			error = EINVAL;
298 			break;
299 		}
300 		switch (msg->header.cmd) {
301 		case NGM_SOURCE_GET_STATS:
302 		case NGM_SOURCE_CLR_STATS:
303 		case NGM_SOURCE_GETCLR_STATS:
304                     {
305 			struct ng_source_stats *stats;
306 
307                         if (msg->header.cmd != NGM_SOURCE_CLR_STATS) {
308                                 NG_MKRESPONSE(resp, msg,
309                                     sizeof(*stats), M_NOWAIT);
310 				if (resp == NULL) {
311 					error = ENOMEM;
312 					goto done;
313 				}
314 				sc->stats.queueOctets = sc->queueOctets;
315 				sc->stats.queueFrames = sc->snd_queue.ifq_len;
316 				if ((sc->node->nd_flags & NG_SOURCE_ACTIVE)
317 				    && !timevalisset(&sc->stats.endTime)) {
318 					getmicrotime(&sc->stats.elapsedTime);
319 					timevalsub(&sc->stats.elapsedTime,
320 					    &sc->stats.startTime);
321 				}
322 				stats = (struct ng_source_stats *)resp->data;
323 				bcopy(&sc->stats, stats, sizeof(* stats));
324                         }
325                         if (msg->header.cmd != NGM_SOURCE_GET_STATS)
326 				bzero(&sc->stats, sizeof(sc->stats));
327 		    }
328 		    break;
329 		case NGM_SOURCE_START:
330 		    {
331 			uint64_t packets;
332 
333 			if (msg->header.arglen != sizeof(uint64_t)) {
334 				error = EINVAL;
335 				break;
336 			}
337 
338 			packets = *(uint64_t *)msg->data;
339 
340 			error = ng_source_start(sc, packets);
341 
342 		    	break;
343 		    }
344 		case NGM_SOURCE_STOP:
345 			ng_source_stop(sc);
346 			break;
347 		case NGM_SOURCE_CLR_DATA:
348 			ng_source_clr_data(sc);
349 			break;
350 		case NGM_SOURCE_SETIFACE:
351 		    {
352 			char *ifname = (char *)msg->data;
353 
354 			if (msg->header.arglen < 2) {
355 				error = EINVAL;
356 				break;
357 			}
358 
359 			ng_source_store_output_ifp(sc, ifname);
360 			break;
361 		    }
362 		case NGM_SOURCE_SETPPS:
363 		    {
364 			uint32_t pps;
365 
366 			if (msg->header.arglen != sizeof(uint32_t)) {
367 				error = EINVAL;
368 				break;
369 			}
370 
371 			pps = *(uint32_t *)msg->data;
372 
373 			sc->stats.maxPps = pps;
374 
375 			break;
376 		    }
377 		default:
378 			error = EINVAL;
379 			break;
380 		}
381 		break;
382 	case NGM_ETHER_COOKIE:
383 		if (!(msg->header.flags & NGF_RESP)) {
384 			error = EINVAL;
385 			break;
386 		}
387 		switch (msg->header.cmd) {
388 		case NGM_ETHER_GET_IFNAME:
389 		    {
390 			char *ifname = (char *)msg->data;
391 
392 			if (msg->header.arglen < 2) {
393 				error = EINVAL;
394 				break;
395 			}
396 
397 			if (ng_source_store_output_ifp(sc, ifname) == 0)
398 				ng_source_set_autosrc(sc, 0);
399 			break;
400 		    }
401 		default:
402 			error = EINVAL;
403 		}
404 		break;
405 	default:
406 		error = EINVAL;
407 		break;
408 	}
409 
410 done:
411 	/* Take care of synchronous response, if any. */
412 	NG_RESPOND_MSG(error, node, item, resp);
413 	/* Free the message and return. */
414 	NG_FREE_MSG(msg);
415 	return (error);
416 }
417 
418 /*
419  * Receive data on a hook
420  *
421  * If data comes in the input hook, enqueue it on the send queue.
422  * If data comes in the output hook, discard it.
423  */
424 static int
425 ng_source_rcvdata(hook_p hook, item_p item)
426 {
427 	sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
428 	struct mbuf *m;
429 	int error = 0;
430 
431 	NGI_GET_M(item, m);
432 	NG_FREE_ITEM(item);
433 
434 	/* Which hook? */
435 	if (hook == sc->output) {
436 		/* discard */
437 		NG_FREE_M(m);
438 		return (error);
439 	}
440 	KASSERT(hook == sc->input, ("%s: no hook!", __func__));
441 
442 	/* Enqueue packet. */
443 	/* XXX should we check IF_QFULL() ? */
444 	_IF_ENQUEUE(&sc->snd_queue, m);
445 	sc->queueOctets += m->m_pkthdr.len;
446 
447 	return (0);
448 }
449 
450 /*
451  * Shutdown processing
452  */
453 static int
454 ng_source_rmnode(node_p node)
455 {
456 	sc_p sc = NG_NODE_PRIVATE(node);
457 
458 	ng_source_stop(sc);
459 	ng_source_clr_data(sc);
460 	NG_NODE_SET_PRIVATE(node, NULL);
461 	NG_NODE_UNREF(node);
462 	free(sc, M_NETGRAPH);
463 
464 	return (0);
465 }
466 
467 /*
468  * Hook disconnection
469  */
470 static int
471 ng_source_disconnect(hook_p hook)
472 {
473 	sc_p sc;
474 
475 	sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
476 	KASSERT(sc != NULL, ("%s: null node private", __func__));
477 	if (NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0 || hook == sc->output)
478 		ng_rmnode_self(NG_HOOK_NODE(hook));
479 	return (0);
480 }
481 
482 /*
483  * Set sc->output_ifp to point to the the struct ifnet of the interface
484  * reached via our output hook.
485  */
486 static int
487 ng_source_store_output_ifp(sc_p sc, char *ifname)
488 {
489 	struct ifnet *ifp;
490 	int s;
491 
492 	ifp = ifunit(ifname);
493 
494 	if (ifp == NULL) {
495 		printf("%s: can't find interface %d\n", __func__, if_index);
496 		return (EINVAL);
497 	}
498 	sc->output_ifp = ifp;
499 
500 #if 1
501 	/* XXX mucking with a drivers ifqueue size is ugly but we need it
502 	 * to queue a lot of packets to get close to line rate on a gigabit
503 	 * interface with small packets.
504 	 * XXX we should restore the original value at stop or disconnect
505 	 */
506 	s = splimp();		/* XXX is this required? */
507 	if (ifp->if_snd.ifq_maxlen < NG_SOURCE_DRIVER_IFQ_MAXLEN) {
508 		printf("ng_source: changing ifq_maxlen from %d to %d\n",
509 		    ifp->if_snd.ifq_maxlen, NG_SOURCE_DRIVER_IFQ_MAXLEN);
510 		ifp->if_snd.ifq_maxlen = NG_SOURCE_DRIVER_IFQ_MAXLEN;
511 	}
512 	splx(s);
513 #endif
514 	return (0);
515 }
516 
517 /*
518  * Set the attached ethernet node's ethernet source address override flag.
519  */
520 static int
521 ng_source_set_autosrc(sc_p sc, uint32_t flag)
522 {
523 	struct ng_mesg *msg;
524 	int error = 0;
525 
526 	NG_MKMESSAGE(msg, NGM_ETHER_COOKIE, NGM_ETHER_SET_AUTOSRC,
527 	    sizeof (uint32_t), M_NOWAIT);
528 	if (msg == NULL)
529 		return(ENOBUFS);
530 
531 	*(uint32_t *)msg->data = flag;
532 	NG_SEND_MSG_HOOK(error, sc->node, msg, sc->output, 0);
533 	return (error);
534 }
535 
536 /*
537  * Clear out the data we've queued
538  */
539 static void
540 ng_source_clr_data (sc_p sc)
541 {
542 	struct mbuf *m;
543 
544 	for (;;) {
545 		_IF_DEQUEUE(&sc->snd_queue, m);
546 		if (m == NULL)
547 			break;
548 		NG_FREE_M(m);
549 	}
550 	sc->queueOctets = 0;
551 }
552 
553 /*
554  * Start sending queued data out the output hook
555  */
556 static int
557 ng_source_start(sc_p sc, uint64_t packets)
558 {
559 	if (sc->output_ifp == NULL) {
560 		printf("ng_source: start without iface configured\n");
561 		return (ENXIO);
562 	}
563 
564 	if (sc->node->nd_flags & NG_SOURCE_ACTIVE)
565 		return (EBUSY);
566 
567 	sc->node->nd_flags |= NG_SOURCE_ACTIVE;
568 
569 	sc->packets = packets;
570 	timevalclear(&sc->stats.elapsedTime);
571 	timevalclear(&sc->stats.endTime);
572 	getmicrotime(&sc->stats.startTime);
573 	getmicrotime(&sc->stats.lastTime);
574 	ng_callout(&sc->intr_ch, sc->node, NULL, 0,
575 	    ng_source_intr, sc, 0);
576 
577 	return (0);
578 }
579 
580 /*
581  * Stop sending queued data out the output hook
582  */
583 static void
584 ng_source_stop(sc_p sc)
585 {
586 	ng_uncallout(&sc->intr_ch, sc->node);
587 	sc->node->nd_flags &= ~NG_SOURCE_ACTIVE;
588 	getmicrotime(&sc->stats.endTime);
589 	sc->stats.elapsedTime = sc->stats.endTime;
590 	timevalsub(&sc->stats.elapsedTime, &sc->stats.startTime);
591 }
592 
593 /*
594  * While active called every NG_SOURCE_INTR_TICKS ticks.
595  * Sends as many packets as the interface connected to our
596  * output hook is able to enqueue.
597  */
598 static void
599 ng_source_intr(node_p node, hook_p hook, void *arg1, int arg2)
600 {
601 	sc_p sc = (sc_p)arg1;
602 	struct ifqueue *ifq;
603 	int packets;
604 
605 	KASSERT(sc != NULL, ("%s: null node private", __func__));
606 
607 	if (sc->packets == 0 || sc->output == NULL
608 	    || (sc->node->nd_flags & NG_SOURCE_ACTIVE) == 0) {
609 		ng_source_stop(sc);
610 		return;
611 	}
612 
613 	if (sc->output_ifp != NULL) {
614 		ifq = (struct ifqueue *)&sc->output_ifp->if_snd;
615 		packets = ifq->ifq_maxlen - ifq->ifq_len;
616 	} else
617 		packets = sc->snd_queue.ifq_len;
618 
619 	if (sc->stats.maxPps != 0) {
620 		struct timeval	now, elapsed;
621 		uint64_t	usec;
622 		int		maxpkt;
623 
624 		getmicrotime(&now);
625 		elapsed = now;
626 		timevalsub(&elapsed, &sc->stats.lastTime);
627 		usec = elapsed.tv_sec * 1000000 + elapsed.tv_usec;
628 		maxpkt = (uint64_t)sc->stats.maxPps * usec / 1000000;
629 		sc->stats.lastTime = now;
630 		if (packets > maxpkt)
631 			packets = maxpkt;
632 	}
633 
634 	ng_source_send(sc, packets, NULL);
635 	if (sc->packets == 0)
636 		ng_source_stop(sc);
637 	else
638 		ng_callout(&sc->intr_ch, node, NULL, NG_SOURCE_INTR_TICKS,
639 		    ng_source_intr, sc, 0);
640 }
641 
642 /*
643  * Send packets out our output hook.
644  */
645 static int
646 ng_source_send(sc_p sc, int tosend, int *sent_p)
647 {
648 	struct mbuf *m, *m2;
649 	int sent;
650 	int error = 0;
651 
652 	KASSERT(tosend >= 0, ("%s: negative tosend param", __func__));
653 	KASSERT(sc->node->nd_flags & NG_SOURCE_ACTIVE,
654 	    ("%s: inactive node", __func__));
655 
656 	if ((uint64_t)tosend > sc->packets)
657 		tosend = sc->packets;
658 
659 	/* Go through the queue sending packets one by one. */
660 	for (sent = 0; error == 0 && sent < tosend; ++sent) {
661 		_IF_DEQUEUE(&sc->snd_queue, m);
662 		if (m == NULL)
663 			break;
664 
665 		/* Duplicate the packet. */
666 		m2 = m_copypacket(m, M_DONTWAIT);
667 		if (m2 == NULL) {
668 			_IF_PREPEND(&sc->snd_queue, m);
669 			error = ENOBUFS;
670 			break;
671 		}
672 
673 		/* Re-enqueue the original packet for us. */
674 		_IF_ENQUEUE(&sc->snd_queue, m);
675 
676 		sc->stats.outFrames++;
677 		sc->stats.outOctets += m2->m_pkthdr.len;
678 		NG_SEND_DATA_ONLY(error, sc->output, m2);
679 		if (error)
680 			break;
681 	}
682 
683 	sc->packets -= sent;
684 	if (sent_p != NULL)
685 		*sent_p = sent;
686 	return (error);
687 }
688