xref: /freebsd/sys/netgraph/ng_source.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
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
39  */
40 
41 #include <sys/cdefs.h>
42 /*
43  * This node is used for high speed packet geneneration.  It queues
44  * all data received on its 'input' hook and when told to start via
45  * a control message it sends the packets out its 'output' hook.  In
46  * this way this node can be preloaded with a packet stream which it
47  * can then send continuously as fast as possible.
48  *
49  * Currently it just copies the mbufs as required.  It could do various
50  * tricks to try and avoid this.  Probably the best performance would
51  * be achieved by modifying the appropriate drivers to be told to
52  * self-re-enqueue packets (e.g. the if_bge driver could reuse the same
53  * transmit descriptors) under control of this node; perhaps via some
54  * flag in the mbuf or some such.  The node could peek at an appropriate
55  * ifnet flag to see if such support is available for the connected
56  * interface.
57  */
58 
59 #include <sys/param.h>
60 #include <sys/systm.h>
61 #include <sys/errno.h>
62 #include <sys/kernel.h>
63 #include <sys/malloc.h>
64 #include <sys/mbuf.h>
65 #include <sys/socket.h>
66 #include <sys/syslog.h>
67 #include <net/if.h>
68 #include <net/if_var.h>
69 #include <net/if_private.h>
70 #include <netgraph/ng_message.h>
71 #include <netgraph/netgraph.h>
72 #include <netgraph/ng_parse.h>
73 #include <netgraph/ng_ether.h>
74 #include <netgraph/ng_source.h>
75 
76 #define NG_SOURCE_INTR_TICKS		1
77 #define NG_SOURCE_DRIVER_IFQ_MAXLEN	(4*1024)
78 
79 #define	mtod_off(m,off,t)	((t)(mtod((m),caddr_t)+(off)))
80 
81 /* Per node info */
82 struct privdata {
83 	node_p				node;
84 	hook_p				input;
85 	hook_p				output;
86 	struct ng_source_stats		stats;
87 	struct mbufq			snd_queue;	/* packets to send */
88 	struct mbuf			*last_packet;	/* last pkt in queue */
89 	struct ifnet			*output_ifp;
90 	struct callout			intr_ch;
91 	uint64_t			packets;	/* packets to send */
92 	uint32_t			queueOctets;
93 	struct ng_source_embed_info	embed_timestamp;
94 	struct ng_source_embed_cnt_info	embed_counter[NG_SOURCE_COUNTERS];
95 };
96 typedef struct privdata *sc_p;
97 
98 /* Node flags */
99 #define NG_SOURCE_ACTIVE	(NGF_TYPE1)
100 
101 /* Netgraph methods */
102 static ng_constructor_t	ng_source_constructor;
103 static ng_rcvmsg_t	ng_source_rcvmsg;
104 static ng_shutdown_t	ng_source_rmnode;
105 static ng_newhook_t	ng_source_newhook;
106 static ng_connect_t	ng_source_connect;
107 static ng_rcvdata_t	ng_source_rcvdata;
108 static ng_disconnect_t	ng_source_disconnect;
109 
110 /* Other functions */
111 static void		ng_source_intr(node_p, hook_p, void *, int);
112 static void		ng_source_clr_data (sc_p);
113 static int		ng_source_start (sc_p, uint64_t);
114 static void		ng_source_stop (sc_p);
115 static int		ng_source_send (sc_p, int, int *);
116 static int		ng_source_store_output_ifp(sc_p, char *);
117 static void		ng_source_packet_mod(sc_p, struct mbuf *,
118 			    int, int, caddr_t, int);
119 static void		ng_source_mod_counter(sc_p sc,
120 			    struct ng_source_embed_cnt_info *cnt,
121 			    struct mbuf *m, int increment);
122 static int		ng_source_dup_mod(sc_p, struct mbuf *,
123 			    struct mbuf **);
124 
125 /* Parse type for timeval */
126 static const struct ng_parse_struct_field ng_source_timeval_type_fields[] = {
127 #ifdef __i386__
128 	{ "tv_sec",		&ng_parse_int32_type	},
129 #else
130 	{ "tv_sec",		&ng_parse_int64_type	},
131 #endif
132 #ifdef __LP64__
133 	{ "tv_usec",		&ng_parse_int64_type	},
134 #else
135 	{ "tv_usec",		&ng_parse_int32_type	},
136 #endif
137 	{ NULL }
138 };
139 const struct ng_parse_type ng_source_timeval_type = {
140 	&ng_parse_struct_type,
141 	&ng_source_timeval_type_fields
142 };
143 
144 /* Parse type for struct ng_source_stats */
145 static const struct ng_parse_struct_field ng_source_stats_type_fields[]
146 	= NG_SOURCE_STATS_TYPE_INFO;
147 static const struct ng_parse_type ng_source_stats_type = {
148 	&ng_parse_struct_type,
149 	&ng_source_stats_type_fields
150 };
151 
152 /* Parse type for struct ng_source_embed_info */
153 static const struct ng_parse_struct_field ng_source_embed_type_fields[] =
154 	NG_SOURCE_EMBED_TYPE_INFO;
155 static const struct ng_parse_type ng_source_embed_type = {
156 	&ng_parse_struct_type,
157 	&ng_source_embed_type_fields
158 };
159 
160 /* Parse type for struct ng_source_embed_cnt_info */
161 static const struct ng_parse_struct_field ng_source_embed_cnt_type_fields[] =
162 	NG_SOURCE_EMBED_CNT_TYPE_INFO;
163 static const struct ng_parse_type ng_source_embed_cnt_type = {
164 	&ng_parse_struct_type,
165 	&ng_source_embed_cnt_type_fields
166 };
167 
168 /* List of commands and how to convert arguments to/from ASCII */
169 static const struct ng_cmdlist ng_source_cmds[] = {
170 	{
171 	  NGM_SOURCE_COOKIE,
172 	  NGM_SOURCE_GET_STATS,
173 	  "getstats",
174 	  NULL,
175 	  &ng_source_stats_type
176 	},
177 	{
178 	  NGM_SOURCE_COOKIE,
179 	  NGM_SOURCE_CLR_STATS,
180 	  "clrstats",
181 	  NULL,
182 	  NULL
183 	},
184 	{
185 	  NGM_SOURCE_COOKIE,
186 	  NGM_SOURCE_GETCLR_STATS,
187 	  "getclrstats",
188 	  NULL,
189 	  &ng_source_stats_type
190 	},
191 	{
192 	  NGM_SOURCE_COOKIE,
193 	  NGM_SOURCE_START,
194 	  "start",
195 	  &ng_parse_uint64_type,
196 	  NULL
197 	},
198 	{
199 	  NGM_SOURCE_COOKIE,
200 	  NGM_SOURCE_STOP,
201 	  "stop",
202 	  NULL,
203 	  NULL
204 	},
205 	{
206 	  NGM_SOURCE_COOKIE,
207 	  NGM_SOURCE_CLR_DATA,
208 	  "clrdata",
209 	  NULL,
210 	  NULL
211 	},
212 	{
213 	  NGM_SOURCE_COOKIE,
214 	  NGM_SOURCE_SETIFACE,
215 	  "setiface",
216 	  &ng_parse_string_type,
217 	  NULL
218 	},
219 	{
220 	  NGM_SOURCE_COOKIE,
221 	  NGM_SOURCE_SETPPS,
222 	  "setpps",
223 	  &ng_parse_uint32_type,
224 	  NULL
225 	},
226 	{
227 	  NGM_SOURCE_COOKIE,
228 	  NGM_SOURCE_SET_TIMESTAMP,
229 	  "settimestamp",
230 	  &ng_source_embed_type,
231 	  NULL
232 	},
233 	{
234 	  NGM_SOURCE_COOKIE,
235 	  NGM_SOURCE_GET_TIMESTAMP,
236 	  "gettimestamp",
237 	  NULL,
238 	  &ng_source_embed_type
239 	},
240 	{
241 	  NGM_SOURCE_COOKIE,
242 	  NGM_SOURCE_SET_COUNTER,
243 	  "setcounter",
244 	  &ng_source_embed_cnt_type,
245 	  NULL
246 	},
247 	{
248 	  NGM_SOURCE_COOKIE,
249 	  NGM_SOURCE_GET_COUNTER,
250 	  "getcounter",
251 	  &ng_parse_uint8_type,
252 	  &ng_source_embed_cnt_type
253 	},
254 	{ 0 }
255 };
256 
257 /* Netgraph type descriptor */
258 static struct ng_type ng_source_typestruct = {
259 	.version =	NG_ABI_VERSION,
260 	.name =		NG_SOURCE_NODE_TYPE,
261 	.constructor =	ng_source_constructor,
262 	.rcvmsg =	ng_source_rcvmsg,
263 	.shutdown =	ng_source_rmnode,
264 	.newhook =	ng_source_newhook,
265 	.connect =	ng_source_connect,
266 	.rcvdata =	ng_source_rcvdata,
267 	.disconnect =	ng_source_disconnect,
268 	.cmdlist =	ng_source_cmds,
269 };
270 NETGRAPH_INIT(source, &ng_source_typestruct);
271 
272 static int ng_source_set_autosrc(sc_p, uint32_t);
273 
274 /*
275  * Node constructor
276  */
277 static int
278 ng_source_constructor(node_p node)
279 {
280 	sc_p sc;
281 
282 	sc = malloc(sizeof(*sc), M_NETGRAPH, M_WAITOK | M_ZERO);
283 
284 	NG_NODE_SET_PRIVATE(node, sc);
285 	sc->node = node;
286 	mbufq_init(&sc->snd_queue, 2048);
287 	ng_callout_init(&sc->intr_ch);
288 
289 	return (0);
290 }
291 
292 /*
293  * Add a hook
294  */
295 static int
296 ng_source_newhook(node_p node, hook_p hook, const char *name)
297 {
298 	sc_p sc = NG_NODE_PRIVATE(node);
299 
300 	if (strcmp(name, NG_SOURCE_HOOK_INPUT) == 0) {
301 		sc->input = hook;
302 	} else if (strcmp(name, NG_SOURCE_HOOK_OUTPUT) == 0) {
303 		sc->output = hook;
304 		sc->output_ifp = NULL;
305 		bzero(&sc->stats, sizeof(sc->stats));
306 	} else
307 		return (EINVAL);
308 
309 	return (0);
310 }
311 
312 /*
313  * Hook has been added
314  */
315 static int
316 ng_source_connect(hook_p hook)
317 {
318 	sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
319 	struct ng_mesg *msg;
320 	int dummy_error = 0;
321 
322 	/*
323 	 * If this is "output" hook, then request information
324 	 * from our downstream.
325 	 */
326 	if (hook == sc->output) {
327 		NG_MKMESSAGE(msg, NGM_ETHER_COOKIE, NGM_ETHER_GET_IFNAME,
328 		    0, M_NOWAIT);
329 		if (msg == NULL)
330 			return (ENOBUFS);
331 
332 		/*
333 		 * Our hook and peer hook have HK_INVALID flag set,
334 		 * so we can't use NG_SEND_MSG_HOOK() macro here.
335 		 */
336 		NG_SEND_MSG_ID(dummy_error, sc->node, msg,
337 		    NG_NODE_ID(NG_PEER_NODE(sc->output)), NG_NODE_ID(sc->node));
338 	}
339 
340 	return (0);
341 }
342 
343 /*
344  * Receive a control message
345  */
346 static int
347 ng_source_rcvmsg(node_p node, item_p item, hook_p lasthook)
348 {
349 	sc_p sc = NG_NODE_PRIVATE(node);
350 	struct ng_mesg *msg, *resp = NULL;
351 	int error = 0;
352 
353 	NGI_GET_MSG(item, msg);
354 
355 	switch (msg->header.typecookie) {
356 	case NGM_SOURCE_COOKIE:
357 		if (msg->header.flags & NGF_RESP) {
358 			error = EINVAL;
359 			break;
360 		}
361 		switch (msg->header.cmd) {
362 		case NGM_SOURCE_GET_STATS:
363 		case NGM_SOURCE_CLR_STATS:
364 		case NGM_SOURCE_GETCLR_STATS:
365                     {
366 			struct ng_source_stats *stats;
367 
368                         if (msg->header.cmd != NGM_SOURCE_CLR_STATS) {
369                                 NG_MKRESPONSE(resp, msg,
370                                     sizeof(*stats), M_NOWAIT);
371 				if (resp == NULL) {
372 					error = ENOMEM;
373 					goto done;
374 				}
375 				sc->stats.queueOctets = sc->queueOctets;
376 				sc->stats.queueFrames = mbufq_len(&sc->snd_queue);
377 				if ((sc->node->nd_flags & NG_SOURCE_ACTIVE)
378 				    && !timevalisset(&sc->stats.endTime)) {
379 					getmicrotime(&sc->stats.elapsedTime);
380 					timevalsub(&sc->stats.elapsedTime,
381 					    &sc->stats.startTime);
382 				}
383 				stats = (struct ng_source_stats *)resp->data;
384 				bcopy(&sc->stats, stats, sizeof(* stats));
385                         }
386                         if (msg->header.cmd != NGM_SOURCE_GET_STATS)
387 				bzero(&sc->stats, sizeof(sc->stats));
388 		    }
389 		    break;
390 		case NGM_SOURCE_START:
391 		    {
392 			uint64_t packets;
393 
394 			if (msg->header.arglen != sizeof(uint64_t)) {
395 				error = EINVAL;
396 				break;
397 			}
398 
399 			packets = *(uint64_t *)msg->data;
400 
401 			error = ng_source_start(sc, packets);
402 
403 		    	break;
404 		    }
405 		case NGM_SOURCE_STOP:
406 			ng_source_stop(sc);
407 			break;
408 		case NGM_SOURCE_CLR_DATA:
409 			ng_source_clr_data(sc);
410 			break;
411 		case NGM_SOURCE_SETIFACE:
412 		    {
413 			char *ifname = (char *)msg->data;
414 
415 			if (msg->header.arglen < 2) {
416 				error = EINVAL;
417 				break;
418 			}
419 
420 			ng_source_store_output_ifp(sc, ifname);
421 			break;
422 		    }
423 		case NGM_SOURCE_SETPPS:
424 		    {
425 			uint32_t pps;
426 
427 			if (msg->header.arglen != sizeof(uint32_t)) {
428 				error = EINVAL;
429 				break;
430 			}
431 
432 			pps = *(uint32_t *)msg->data;
433 
434 			sc->stats.maxPps = pps;
435 
436 			break;
437 		    }
438 		case NGM_SOURCE_SET_TIMESTAMP:
439 		    {
440 			struct ng_source_embed_info *embed;
441 
442 			if (msg->header.arglen != sizeof(*embed)) {
443 				error = EINVAL;
444 				goto done;
445 			}
446 			embed = (struct ng_source_embed_info *)msg->data;
447 			bcopy(embed, &sc->embed_timestamp, sizeof(*embed));
448 
449 			break;
450 		    }
451 		case NGM_SOURCE_GET_TIMESTAMP:
452 		    {
453 			struct ng_source_embed_info *embed;
454 
455 			NG_MKRESPONSE(resp, msg, sizeof(*embed), M_NOWAIT);
456 			if (resp == NULL) {
457 				error = ENOMEM;
458 				goto done;
459 			}
460 			embed = (struct ng_source_embed_info *)resp->data;
461 			bcopy(&sc->embed_timestamp, embed, sizeof(*embed));
462 
463 			break;
464 		    }
465 		case NGM_SOURCE_SET_COUNTER:
466 		    {
467 			struct ng_source_embed_cnt_info *embed;
468 
469 			if (msg->header.arglen != sizeof(*embed)) {
470 				error = EINVAL;
471 				goto done;
472 			}
473 			embed = (struct ng_source_embed_cnt_info *)msg->data;
474 			if (embed->index >= NG_SOURCE_COUNTERS ||
475 			    !(embed->width == 1 || embed->width == 2 ||
476 			    embed->width == 4)) {
477 				error = EINVAL;
478 				goto done;
479 			}
480 			bcopy(embed, &sc->embed_counter[embed->index],
481 			    sizeof(*embed));
482 
483 			break;
484 		    }
485 		case NGM_SOURCE_GET_COUNTER:
486 		    {
487 			uint8_t index = *(uint8_t *)msg->data;
488 			struct ng_source_embed_cnt_info *embed;
489 
490 			if (index >= NG_SOURCE_COUNTERS) {
491 				error = EINVAL;
492 				goto done;
493 			}
494 			NG_MKRESPONSE(resp, msg, sizeof(*embed), M_NOWAIT);
495 			if (resp == NULL) {
496 				error = ENOMEM;
497 				goto done;
498 			}
499 			embed = (struct ng_source_embed_cnt_info *)resp->data;
500 			bcopy(&sc->embed_counter[index], embed, sizeof(*embed));
501 
502 			break;
503 		    }
504 		default:
505 			error = EINVAL;
506 			break;
507 		}
508 		break;
509 	case NGM_ETHER_COOKIE:
510 		if (!(msg->header.flags & NGF_RESP)) {
511 			error = EINVAL;
512 			break;
513 		}
514 		switch (msg->header.cmd) {
515 		case NGM_ETHER_GET_IFNAME:
516 		    {
517 			char *ifname = (char *)msg->data;
518 
519 			if (msg->header.arglen < 2) {
520 				error = EINVAL;
521 				break;
522 			}
523 
524 			if (ng_source_store_output_ifp(sc, ifname) == 0)
525 				ng_source_set_autosrc(sc, 0);
526 			break;
527 		    }
528 		default:
529 			error = EINVAL;
530 		}
531 		break;
532 	default:
533 		error = EINVAL;
534 		break;
535 	}
536 
537 done:
538 	/* Take care of synchronous response, if any. */
539 	NG_RESPOND_MSG(error, node, item, resp);
540 	/* Free the message and return. */
541 	NG_FREE_MSG(msg);
542 	return (error);
543 }
544 
545 /*
546  * Receive data on a hook
547  *
548  * If data comes in the input hook, enqueue it on the send queue.
549  * If data comes in the output hook, discard it.
550  */
551 static int
552 ng_source_rcvdata(hook_p hook, item_p item)
553 {
554 	sc_p sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
555 	struct mbuf *m;
556 	int error = 0;
557 
558 	NGI_GET_M(item, m);
559 	NG_FREE_ITEM(item);
560 
561 	/* Which hook? */
562 	if (hook == sc->output) {
563 		/* discard */
564 		NG_FREE_M(m);
565 		return (error);
566 	}
567 	KASSERT(hook == sc->input, ("%s: no hook!", __func__));
568 
569 	/* Enqueue packet if the queue isn't full. */
570 	error = mbufq_enqueue(&sc->snd_queue, m);
571 	if (error) {
572 		NG_FREE_M(m);
573 		return (error);
574 	}
575 	sc->queueOctets += m->m_pkthdr.len;
576 	sc->last_packet = m;
577 
578 	return (0);
579 }
580 
581 /*
582  * Shutdown processing
583  */
584 static int
585 ng_source_rmnode(node_p node)
586 {
587 	sc_p sc = NG_NODE_PRIVATE(node);
588 
589 	ng_source_stop(sc);
590 	ng_source_clr_data(sc);
591 	NG_NODE_SET_PRIVATE(node, NULL);
592 	NG_NODE_UNREF(node);
593 	free(sc, M_NETGRAPH);
594 
595 	return (0);
596 }
597 
598 /*
599  * Hook disconnection
600  */
601 static int
602 ng_source_disconnect(hook_p hook)
603 {
604 	sc_p sc;
605 
606 	sc = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
607 	KASSERT(sc != NULL, ("%s: null node private", __func__));
608 	if (NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0 || hook == sc->output)
609 		ng_rmnode_self(NG_HOOK_NODE(hook));
610 	return (0);
611 }
612 
613 /*
614  * Set sc->output_ifp to point to the struct ifnet of the interface
615  * reached via our output hook.
616  */
617 static int
618 ng_source_store_output_ifp(sc_p sc, char *ifname)
619 {
620 	struct ifnet *ifp;
621 
622 	ifp = ifunit(ifname);
623 
624 	if (ifp == NULL) {
625 		printf("%s: can't find interface %s\n", __func__, ifname);
626 		return (EINVAL);
627 	}
628 	sc->output_ifp = ifp;
629 
630 #if 1
631 	/* XXX mucking with a drivers ifqueue size is ugly but we need it
632 	 * to queue a lot of packets to get close to line rate on a gigabit
633 	 * interface with small packets.
634 	 * XXX we should restore the original value at stop or disconnect
635 	 */
636 	if (ifp->if_snd.ifq_maxlen < NG_SOURCE_DRIVER_IFQ_MAXLEN) {
637 		printf("ng_source: changing ifq_maxlen from %d to %d\n",
638 		    ifp->if_snd.ifq_maxlen, NG_SOURCE_DRIVER_IFQ_MAXLEN);
639 		ifp->if_snd.ifq_maxlen = NG_SOURCE_DRIVER_IFQ_MAXLEN;
640 	}
641 #endif
642 	return (0);
643 }
644 
645 /*
646  * Set the attached ethernet node's ethernet source address override flag.
647  */
648 static int
649 ng_source_set_autosrc(sc_p sc, uint32_t flag)
650 {
651 	struct ng_mesg *msg;
652 	int error = 0;
653 
654 	NG_MKMESSAGE(msg, NGM_ETHER_COOKIE, NGM_ETHER_SET_AUTOSRC,
655 	    sizeof (uint32_t), M_NOWAIT);
656 	if (msg == NULL)
657 		return(ENOBUFS);
658 
659 	*(uint32_t *)msg->data = flag;
660 	NG_SEND_MSG_HOOK(error, sc->node, msg, sc->output, 0);
661 	return (error);
662 }
663 
664 /*
665  * Clear out the data we've queued
666  */
667 static void
668 ng_source_clr_data (sc_p sc)
669 {
670 	struct mbuf *m;
671 
672 	for (;;) {
673 		m =  mbufq_dequeue(&sc->snd_queue);
674 		if (m == NULL)
675 			break;
676 		NG_FREE_M(m);
677 	}
678 	sc->queueOctets = 0;
679 	sc->last_packet = NULL;
680 }
681 
682 /*
683  * Start sending queued data out the output hook
684  */
685 static int
686 ng_source_start(sc_p sc, uint64_t packets)
687 {
688 	if (sc->output_ifp == NULL && sc->stats.maxPps == 0) {
689 		printf("ng_source: start without iface or pps configured\n");
690 		return (ENXIO);
691 	}
692 
693 	if (sc->node->nd_flags & NG_SOURCE_ACTIVE)
694 		return (EBUSY);
695 
696 	sc->node->nd_flags |= NG_SOURCE_ACTIVE;
697 
698 	sc->packets = packets;
699 	timevalclear(&sc->stats.elapsedTime);
700 	timevalclear(&sc->stats.endTime);
701 	getmicrotime(&sc->stats.startTime);
702 	getmicrotime(&sc->stats.lastTime);
703 	ng_callout(&sc->intr_ch, sc->node, NULL, 0,
704 	    ng_source_intr, sc, 0);
705 
706 	return (0);
707 }
708 
709 /*
710  * Stop sending queued data out the output hook
711  */
712 static void
713 ng_source_stop(sc_p sc)
714 {
715 	ng_uncallout(&sc->intr_ch, sc->node);
716 	sc->node->nd_flags &= ~NG_SOURCE_ACTIVE;
717 	getmicrotime(&sc->stats.endTime);
718 	sc->stats.elapsedTime = sc->stats.endTime;
719 	timevalsub(&sc->stats.elapsedTime, &sc->stats.startTime);
720 }
721 
722 /*
723  * While active called every NG_SOURCE_INTR_TICKS ticks.
724  * Sends as many packets as the interface connected to our
725  * output hook is able to enqueue.
726  */
727 static void
728 ng_source_intr(node_p node, hook_p hook, void *arg1, int arg2)
729 {
730 	sc_p sc = (sc_p)arg1;
731 	struct ifqueue *ifq;
732 	int packets;
733 
734 	KASSERT(sc != NULL, ("%s: null node private", __func__));
735 
736 	if (sc->packets == 0 || sc->output == NULL
737 	    || (sc->node->nd_flags & NG_SOURCE_ACTIVE) == 0) {
738 		ng_source_stop(sc);
739 		return;
740 	}
741 
742 	if (sc->output_ifp != NULL) {
743 		ifq = (struct ifqueue *)&sc->output_ifp->if_snd;
744 		packets = ifq->ifq_maxlen - ifq->ifq_len;
745 	} else
746 		packets = mbufq_len(&sc->snd_queue);
747 
748 	if (sc->stats.maxPps != 0) {
749 		struct timeval	now, elapsed;
750 		uint64_t	usec;
751 		int		maxpkt;
752 
753 		getmicrotime(&now);
754 		elapsed = now;
755 		timevalsub(&elapsed, &sc->stats.lastTime);
756 		usec = elapsed.tv_sec * 1000000 + elapsed.tv_usec;
757 		maxpkt = (uint64_t)sc->stats.maxPps * usec / 1000000;
758 		sc->stats.lastTime = now;
759 		if (packets > maxpkt)
760 			packets = maxpkt;
761 	}
762 
763 	ng_source_send(sc, packets, NULL);
764 	if (sc->packets == 0)
765 		ng_source_stop(sc);
766 	else
767 		ng_callout(&sc->intr_ch, node, NULL, NG_SOURCE_INTR_TICKS,
768 		    ng_source_intr, sc, 0);
769 }
770 
771 /*
772  * Send packets out our output hook.
773  */
774 static int
775 ng_source_send(sc_p sc, int tosend, int *sent_p)
776 {
777 	struct mbuf *m, *m2;
778 	int sent;
779 	int error = 0;
780 
781 	KASSERT(tosend >= 0, ("%s: negative tosend param", __func__));
782 	KASSERT(sc->node->nd_flags & NG_SOURCE_ACTIVE,
783 	    ("%s: inactive node", __func__));
784 
785 	if ((uint64_t)tosend > sc->packets)
786 		tosend = sc->packets;
787 
788 	/* Go through the queue sending packets one by one. */
789 	for (sent = 0; error == 0 && sent < tosend; ++sent) {
790 		m = mbufq_dequeue(&sc->snd_queue);
791 		if (m == NULL)
792 			break;
793 
794 		/* Duplicate and modify the packet. */
795 		error = ng_source_dup_mod(sc, m, &m2);
796 		if (error) {
797 			if (error == ENOBUFS)
798 				mbufq_prepend(&sc->snd_queue, m);
799 			else
800 				(void)mbufq_enqueue(&sc->snd_queue, m);
801 			break;
802 		}
803 
804 		/*
805 		 * Re-enqueue the original packet for us.  The queue
806 		 * has a free slot, because we dequeued the packet
807 		 * above and this callout function runs under WRITER
808 		 * lock.
809 		 */
810 		error = mbufq_enqueue(&sc->snd_queue, m);
811 		KASSERT(error == 0, ("%s: re-enqueue packet failed", __func__));
812 
813 		sc->stats.outFrames++;
814 		sc->stats.outOctets += m2->m_pkthdr.len;
815 		NG_SEND_DATA_ONLY(error, sc->output, m2);
816 		if (error)
817 			break;
818 	}
819 
820 	sc->packets -= sent;
821 	if (sent_p != NULL)
822 		*sent_p = sent;
823 	return (error);
824 }
825 
826 /*
827  * Modify packet in 'm' by changing 'len' bytes starting at 'offset'
828  * to data in 'cp'.
829  *
830  * The packet data in 'm' must be in a contiguous buffer in a single mbuf.
831  */
832 static void
833 ng_source_packet_mod(sc_p sc, struct mbuf *m, int offset, int len, caddr_t cp,
834     int flags)
835 {
836 	if (len == 0)
837 		return;
838 
839 	/* Can't modify beyond end of packet. */
840 	/* TODO: Pad packet for this case. */
841 	if (offset + len > m->m_len)
842 		return;
843 
844 	bcopy(cp, mtod_off(m, offset, caddr_t), len);
845 }
846 
847 static void
848 ng_source_mod_counter(sc_p sc, struct ng_source_embed_cnt_info *cnt,
849     struct mbuf *m, int increment)
850 {
851 	caddr_t cp;
852 	uint32_t val;
853 
854 	val = htonl(cnt->next_val);
855 	cp = (caddr_t)&val + sizeof(val) - cnt->width;
856 	ng_source_packet_mod(sc, m, cnt->offset, cnt->width, cp, cnt->flags);
857 
858 	if (increment) {
859 		cnt->next_val += increment;
860 
861 		if (increment > 0 && cnt->next_val > cnt->max_val) {
862 			cnt->next_val = cnt->min_val - 1 +
863 			    (cnt->next_val - cnt->max_val);
864 			if (cnt->next_val > cnt->max_val)
865 				cnt->next_val = cnt->max_val;
866 		} else if (increment < 0 && cnt->next_val < cnt->min_val) {
867 			cnt->next_val = cnt->max_val + 1 +
868 			    (cnt->next_val - cnt->min_val);
869 			if (cnt->next_val < cnt->min_val)
870 				cnt->next_val = cnt->max_val;
871 		}
872 	}
873 }
874 
875 static int
876 ng_source_dup_mod(sc_p sc, struct mbuf *m0, struct mbuf **m_ptr)
877 {
878 	struct mbuf *m;
879 	struct ng_source_embed_cnt_info *cnt;
880 	struct ng_source_embed_info *ts;
881 	int modify;
882 	int error = 0;
883 	int i, increment;
884 
885 	/* Are we going to modify packets? */
886 	modify = sc->embed_timestamp.flags & NGM_SOURCE_EMBED_ENABLE;
887 	for (i = 0; !modify && i < NG_SOURCE_COUNTERS; ++i)
888 		modify = sc->embed_counter[i].flags & NGM_SOURCE_EMBED_ENABLE;
889 
890 	/* Duplicate the packet. */
891 	if (modify)
892 		m = m_dup(m0, M_NOWAIT);
893 	else
894 		m = m_copypacket(m0, M_NOWAIT);
895 	if (m == NULL) {
896 		error = ENOBUFS;
897 		goto done;
898 	}
899 	*m_ptr = m;
900 
901 	if (!modify)
902 		goto done;
903 
904 	/* Modify the copied packet for sending. */
905 	KASSERT(M_WRITABLE(m), ("%s: packet not writable", __func__));
906 
907 	for (i = 0; i < NG_SOURCE_COUNTERS; ++i) {
908 		cnt = &sc->embed_counter[i];
909 		if (cnt->flags & NGM_SOURCE_EMBED_ENABLE) {
910 			if ((cnt->flags & NGM_SOURCE_INC_CNT_PER_LIST) == 0 ||
911 			    sc->last_packet == m0)
912 				increment = cnt->increment;
913 			else
914 				increment = 0;
915 			ng_source_mod_counter(sc, cnt, m, increment);
916 		}
917 	}
918 
919 	ts = &sc->embed_timestamp;
920 	if (ts->flags & NGM_SOURCE_EMBED_ENABLE) {
921 		struct timeval now;
922 		getmicrotime(&now);
923 		now.tv_sec = htonl(now.tv_sec);
924 		now.tv_usec = htonl(now.tv_usec);
925 		ng_source_packet_mod(sc, m, ts->offset, sizeof (now),
926 		    (caddr_t)&now, ts->flags);
927 	}
928 
929 done:
930 	return(error);
931 }
932