xref: /freebsd/sys/netgraph/ng_pipe.c (revision 4c9a0adad18263ec8725d9bfc5f560c6ad1da8bd)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004-2010 University of Zagreb
5  * Copyright (c) 2007-2008 FreeBSD Foundation
6  *
7  * This software was developed by the University of Zagreb and the
8  * FreeBSD Foundation under sponsorship by the Stichting NLnet and the
9  * FreeBSD Foundation.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /*
34  * This node permits simple traffic shaping by emulating bandwidth
35  * and delay, as well as random packet losses.
36  * The node has two hooks, upper and lower. Traffic flowing from upper to
37  * lower hook is referenced as downstream, and vice versa. Parameters for
38  * both directions can be set separately, except for delay.
39  */
40 
41 #include <sys/param.h>
42 #include <sys/errno.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
46 #include <sys/mbuf.h>
47 #include <sys/time.h>
48 
49 #include <vm/uma.h>
50 
51 #include <net/vnet.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 
57 #include <netgraph/ng_message.h>
58 #include <netgraph/netgraph.h>
59 #include <netgraph/ng_parse.h>
60 #include <netgraph/ng_pipe.h>
61 
62 static MALLOC_DEFINE(M_NG_PIPE, "ng_pipe", "ng_pipe");
63 
64 /* Packet header struct */
65 struct ngp_hdr {
66 	TAILQ_ENTRY(ngp_hdr)	ngp_link;	/* next pkt in queue */
67 	struct timeval		when;		/* this packet's due time */
68 	struct mbuf		*m;		/* ptr to the packet data */
69 };
70 TAILQ_HEAD(p_head, ngp_hdr);
71 
72 /* FIFO queue struct */
73 struct ngp_fifo {
74 	TAILQ_ENTRY(ngp_fifo)	fifo_le;	/* list of active queues only */
75 	struct p_head		packet_head;	/* FIFO queue head */
76 	u_int32_t		hash;		/* flow signature */
77 	struct timeval		vtime;		/* virtual time, for WFQ */
78 	u_int32_t		rr_deficit;	/* for DRR */
79 	u_int32_t		packets;	/* # of packets in this queue */
80 };
81 
82 /* Per hook info */
83 struct hookinfo {
84 	hook_p			hook;
85 	int			noqueue;	/* bypass any processing */
86 	TAILQ_HEAD(, ngp_fifo)	fifo_head;	/* FIFO queues */
87 	TAILQ_HEAD(, ngp_hdr)	qout_head;	/* delay queue head */
88 	struct timeval		qin_utime;
89 	struct ng_pipe_hookcfg	cfg;
90 	struct ng_pipe_hookrun	run;
91 	struct ng_pipe_hookstat	stats;
92 	uint64_t		*ber_p;		/* loss_p(BER,psize) map */
93 };
94 
95 /* Per node info */
96 struct node_priv {
97 	u_int64_t		delay;
98 	u_int32_t		overhead;
99 	u_int32_t		header_offset;
100 	struct hookinfo		lower;
101 	struct hookinfo		upper;
102 	struct callout		timer;
103 	int			timer_scheduled;
104 };
105 typedef struct node_priv *priv_p;
106 
107 /* Macro for calculating the virtual time for packet dequeueing in WFQ */
108 #define FIFO_VTIME_SORT(plen)						\
109 	if (hinfo->cfg.wfq && hinfo->cfg.bandwidth) {			\
110 		ngp_f->vtime.tv_usec = now->tv_usec + ((uint64_t) (plen) \
111 			+ priv->overhead ) * hinfo->run.fifo_queues *	\
112 			8000000 / hinfo->cfg.bandwidth;			\
113 		ngp_f->vtime.tv_sec = now->tv_sec +			\
114 			ngp_f->vtime.tv_usec / 1000000;			\
115 		ngp_f->vtime.tv_usec = ngp_f->vtime.tv_usec % 1000000;	\
116 		TAILQ_FOREACH(ngp_f1, &hinfo->fifo_head, fifo_le)	\
117 			if (ngp_f1->vtime.tv_sec > ngp_f->vtime.tv_sec || \
118 			    (ngp_f1->vtime.tv_sec == ngp_f->vtime.tv_sec && \
119 			    ngp_f1->vtime.tv_usec > ngp_f->vtime.tv_usec)) \
120 				break;					\
121 		if (ngp_f1 == NULL)					\
122 			TAILQ_INSERT_TAIL(&hinfo->fifo_head, ngp_f, fifo_le); \
123 		else							\
124 			TAILQ_INSERT_BEFORE(ngp_f1, ngp_f, fifo_le);	\
125 	} else								\
126 		TAILQ_INSERT_TAIL(&hinfo->fifo_head, ngp_f, fifo_le);	\
127 
128 static void	parse_cfg(struct ng_pipe_hookcfg *, struct ng_pipe_hookcfg *,
129 			struct hookinfo *, priv_p);
130 static void	pipe_dequeue(struct hookinfo *, struct timeval *);
131 static void	ngp_callout(node_p, hook_p, void *, int);
132 static int	ngp_modevent(module_t, int, void *);
133 
134 /* zone for storing ngp_hdr-s */
135 static uma_zone_t ngp_zone;
136 
137 /* Netgraph methods */
138 static ng_constructor_t	ngp_constructor;
139 static ng_rcvmsg_t	ngp_rcvmsg;
140 static ng_shutdown_t	ngp_shutdown;
141 static ng_newhook_t	ngp_newhook;
142 static ng_rcvdata_t	ngp_rcvdata;
143 static ng_disconnect_t	ngp_disconnect;
144 
145 /* Parse type for struct ng_pipe_hookstat */
146 static const struct ng_parse_struct_field
147 	ng_pipe_hookstat_type_fields[] = NG_PIPE_HOOKSTAT_INFO;
148 static const struct ng_parse_type ng_pipe_hookstat_type = {
149 	&ng_parse_struct_type,
150 	&ng_pipe_hookstat_type_fields
151 };
152 
153 /* Parse type for struct ng_pipe_stats */
154 static const struct ng_parse_struct_field ng_pipe_stats_type_fields[] =
155 	NG_PIPE_STATS_INFO(&ng_pipe_hookstat_type);
156 static const struct ng_parse_type ng_pipe_stats_type = {
157 	&ng_parse_struct_type,
158 	&ng_pipe_stats_type_fields
159 };
160 
161 /* Parse type for struct ng_pipe_hookrun */
162 static const struct ng_parse_struct_field
163 	ng_pipe_hookrun_type_fields[] = NG_PIPE_HOOKRUN_INFO;
164 static const struct ng_parse_type ng_pipe_hookrun_type = {
165 	&ng_parse_struct_type,
166 	&ng_pipe_hookrun_type_fields
167 };
168 
169 /* Parse type for struct ng_pipe_run */
170 static const struct ng_parse_struct_field
171 	ng_pipe_run_type_fields[] = NG_PIPE_RUN_INFO(&ng_pipe_hookrun_type);
172 static const struct ng_parse_type ng_pipe_run_type = {
173 	&ng_parse_struct_type,
174 	&ng_pipe_run_type_fields
175 };
176 
177 /* Parse type for struct ng_pipe_hookcfg */
178 static const struct ng_parse_struct_field
179 	ng_pipe_hookcfg_type_fields[] = NG_PIPE_HOOKCFG_INFO;
180 static const struct ng_parse_type ng_pipe_hookcfg_type = {
181 	&ng_parse_struct_type,
182 	&ng_pipe_hookcfg_type_fields
183 };
184 
185 /* Parse type for struct ng_pipe_cfg */
186 static const struct ng_parse_struct_field
187 	ng_pipe_cfg_type_fields[] = NG_PIPE_CFG_INFO(&ng_pipe_hookcfg_type);
188 static const struct ng_parse_type ng_pipe_cfg_type = {
189 	&ng_parse_struct_type,
190 	&ng_pipe_cfg_type_fields
191 };
192 
193 /* List of commands and how to convert arguments to/from ASCII */
194 static const struct ng_cmdlist ngp_cmds[] = {
195 	{
196 		.cookie =	NGM_PIPE_COOKIE,
197 		.cmd =		NGM_PIPE_GET_STATS,
198 		.name = 	"getstats",
199 		.respType =	 &ng_pipe_stats_type
200 	},
201 	{
202 		.cookie =	NGM_PIPE_COOKIE,
203 		.cmd =		NGM_PIPE_CLR_STATS,
204 		.name =		"clrstats"
205 	},
206 	{
207 		.cookie =	NGM_PIPE_COOKIE,
208 		.cmd =		NGM_PIPE_GETCLR_STATS,
209 		.name =		"getclrstats",
210 		.respType =	&ng_pipe_stats_type
211 	},
212 	{
213 		.cookie =	NGM_PIPE_COOKIE,
214 		.cmd =		NGM_PIPE_GET_RUN,
215 		.name =		"getrun",
216 		.respType =	&ng_pipe_run_type
217 	},
218 	{
219 		.cookie =	NGM_PIPE_COOKIE,
220 		.cmd =		NGM_PIPE_GET_CFG,
221 		.name =		"getcfg",
222 		.respType =	&ng_pipe_cfg_type
223 	},
224 	{
225 		.cookie =	NGM_PIPE_COOKIE,
226 		.cmd =		NGM_PIPE_SET_CFG,
227 		.name =		"setcfg",
228 		.mesgType =	&ng_pipe_cfg_type,
229 	},
230 	{ 0 }
231 };
232 
233 /* Netgraph type descriptor */
234 static struct ng_type ng_pipe_typestruct = {
235 	.version =	NG_ABI_VERSION,
236 	.name =		NG_PIPE_NODE_TYPE,
237 	.mod_event =	ngp_modevent,
238 	.constructor =	ngp_constructor,
239 	.shutdown =	ngp_shutdown,
240 	.rcvmsg =	ngp_rcvmsg,
241 	.newhook =	ngp_newhook,
242 	.rcvdata =	ngp_rcvdata,
243 	.disconnect =	ngp_disconnect,
244 	.cmdlist =	ngp_cmds
245 };
246 NETGRAPH_INIT(pipe, &ng_pipe_typestruct);
247 
248 /* Node constructor */
249 static int
250 ngp_constructor(node_p node)
251 {
252 	priv_p priv;
253 
254 	priv = malloc(sizeof(*priv), M_NG_PIPE, M_ZERO | M_WAITOK);
255 	NG_NODE_SET_PRIVATE(node, priv);
256 
257 	/* Mark node as single-threaded */
258 	NG_NODE_FORCE_WRITER(node);
259 
260 	ng_callout_init(&priv->timer);
261 
262 	return (0);
263 }
264 
265 /* Add a hook */
266 static int
267 ngp_newhook(node_p node, hook_p hook, const char *name)
268 {
269 	const priv_p priv = NG_NODE_PRIVATE(node);
270 	struct hookinfo *hinfo;
271 
272 	if (strcmp(name, NG_PIPE_HOOK_UPPER) == 0) {
273 		bzero(&priv->upper, sizeof(priv->upper));
274 		priv->upper.hook = hook;
275 		NG_HOOK_SET_PRIVATE(hook, &priv->upper);
276 	} else if (strcmp(name, NG_PIPE_HOOK_LOWER) == 0) {
277 		bzero(&priv->lower, sizeof(priv->lower));
278 		priv->lower.hook = hook;
279 		NG_HOOK_SET_PRIVATE(hook, &priv->lower);
280 	} else
281 		return (EINVAL);
282 
283 	/* Load non-zero initial cfg values */
284 	hinfo = NG_HOOK_PRIVATE(hook);
285 	hinfo->cfg.qin_size_limit = 50;
286 	hinfo->cfg.fifo = 1;
287 	hinfo->cfg.droptail = 1;
288 	TAILQ_INIT(&hinfo->fifo_head);
289 	TAILQ_INIT(&hinfo->qout_head);
290 	return (0);
291 }
292 
293 /* Receive a control message */
294 static int
295 ngp_rcvmsg(node_p node, item_p item, hook_p lasthook)
296 {
297 	const priv_p priv = NG_NODE_PRIVATE(node);
298 	struct ng_mesg *resp = NULL;
299 	struct ng_mesg *msg, *flow_msg;
300 	struct ng_pipe_stats *stats;
301 	struct ng_pipe_run *run;
302 	struct ng_pipe_cfg *cfg;
303 	int error = 0;
304 	int prev_down, now_down, cmd;
305 
306 	NGI_GET_MSG(item, msg);
307 	switch (msg->header.typecookie) {
308 	case NGM_PIPE_COOKIE:
309 		switch (msg->header.cmd) {
310 		case NGM_PIPE_GET_STATS:
311 		case NGM_PIPE_CLR_STATS:
312 		case NGM_PIPE_GETCLR_STATS:
313 			if (msg->header.cmd != NGM_PIPE_CLR_STATS) {
314 				NG_MKRESPONSE(resp, msg,
315 				    sizeof(*stats), M_NOWAIT);
316 				if (resp == NULL) {
317 					error = ENOMEM;
318 					break;
319 				}
320 				stats = (struct ng_pipe_stats *) resp->data;
321 				bcopy(&priv->upper.stats, &stats->downstream,
322 				    sizeof(stats->downstream));
323 				bcopy(&priv->lower.stats, &stats->upstream,
324 				    sizeof(stats->upstream));
325 			}
326 			if (msg->header.cmd != NGM_PIPE_GET_STATS) {
327 				bzero(&priv->upper.stats,
328 				    sizeof(priv->upper.stats));
329 				bzero(&priv->lower.stats,
330 				    sizeof(priv->lower.stats));
331 			}
332 			break;
333 		case NGM_PIPE_GET_RUN:
334 			NG_MKRESPONSE(resp, msg, sizeof(*run), M_NOWAIT);
335 			if (resp == NULL) {
336 				error = ENOMEM;
337 				break;
338 			}
339 			run = (struct ng_pipe_run *) resp->data;
340 			bcopy(&priv->upper.run, &run->downstream,
341 				sizeof(run->downstream));
342 			bcopy(&priv->lower.run, &run->upstream,
343 				sizeof(run->upstream));
344 			break;
345 		case NGM_PIPE_GET_CFG:
346 			NG_MKRESPONSE(resp, msg, sizeof(*cfg), M_NOWAIT);
347 			if (resp == NULL) {
348 				error = ENOMEM;
349 				break;
350 			}
351 			cfg = (struct ng_pipe_cfg *) resp->data;
352 			bcopy(&priv->upper.cfg, &cfg->downstream,
353 				sizeof(cfg->downstream));
354 			bcopy(&priv->lower.cfg, &cfg->upstream,
355 				sizeof(cfg->upstream));
356 			cfg->delay = priv->delay;
357 			cfg->overhead = priv->overhead;
358 			cfg->header_offset = priv->header_offset;
359 			if (cfg->upstream.bandwidth ==
360 			    cfg->downstream.bandwidth) {
361 				cfg->bandwidth = cfg->upstream.bandwidth;
362 				cfg->upstream.bandwidth = 0;
363 				cfg->downstream.bandwidth = 0;
364 			} else
365 				cfg->bandwidth = 0;
366 			break;
367 		case NGM_PIPE_SET_CFG:
368 			cfg = (struct ng_pipe_cfg *) msg->data;
369 			if (msg->header.arglen != sizeof(*cfg)) {
370 				error = EINVAL;
371 				break;
372 			}
373 
374 			if (cfg->delay == -1)
375 				priv->delay = 0;
376 			else if (cfg->delay > 0 && cfg->delay < 10000000)
377 				priv->delay = cfg->delay;
378 
379 			if (cfg->bandwidth == -1) {
380 				priv->upper.cfg.bandwidth = 0;
381 				priv->lower.cfg.bandwidth = 0;
382 				priv->overhead = 0;
383 			} else if (cfg->bandwidth >= 100 &&
384 			    cfg->bandwidth <= 1000000000) {
385 				priv->upper.cfg.bandwidth = cfg->bandwidth;
386 				priv->lower.cfg.bandwidth = cfg->bandwidth;
387 				if (cfg->bandwidth >= 10000000)
388 					priv->overhead = 8+4+12; /* Ethernet */
389 				else
390 					priv->overhead = 10; /* HDLC */
391 			}
392 
393 			if (cfg->overhead == -1)
394 				priv->overhead = 0;
395 			else if (cfg->overhead > 0 &&
396 			    cfg->overhead < MAX_OHSIZE)
397 				priv->overhead = cfg->overhead;
398 
399 			if (cfg->header_offset == -1)
400 				priv->header_offset = 0;
401 			else if (cfg->header_offset > 0 &&
402 			    cfg->header_offset < 64)
403 				priv->header_offset = cfg->header_offset;
404 
405 			prev_down = priv->upper.cfg.ber == 1 ||
406 			    priv->lower.cfg.ber == 1;
407 			parse_cfg(&priv->upper.cfg, &cfg->downstream,
408 			    &priv->upper, priv);
409 			parse_cfg(&priv->lower.cfg, &cfg->upstream,
410 			    &priv->lower, priv);
411 			now_down = priv->upper.cfg.ber == 1 ||
412 			    priv->lower.cfg.ber == 1;
413 
414 			if (prev_down != now_down) {
415 				if (now_down)
416 					cmd = NGM_LINK_IS_DOWN;
417 				else
418 					cmd = NGM_LINK_IS_UP;
419 
420 				if (priv->lower.hook != NULL) {
421 					NG_MKMESSAGE(flow_msg, NGM_FLOW_COOKIE,
422 					    cmd, 0, M_NOWAIT);
423 					if (flow_msg != NULL)
424 						NG_SEND_MSG_HOOK(error, node,
425 						    flow_msg, priv->lower.hook,
426 						    0);
427 				}
428 				if (priv->upper.hook != NULL) {
429 					NG_MKMESSAGE(flow_msg, NGM_FLOW_COOKIE,
430 					    cmd, 0, M_NOWAIT);
431 					if (flow_msg != NULL)
432 						NG_SEND_MSG_HOOK(error, node,
433 						    flow_msg, priv->upper.hook,
434 						    0);
435 				}
436 			}
437 			break;
438 		default:
439 			error = EINVAL;
440 			break;
441 		}
442 		break;
443 	default:
444 		error = EINVAL;
445 		break;
446 	}
447 	NG_RESPOND_MSG(error, node, item, resp);
448 	NG_FREE_MSG(msg);
449 
450 	return (error);
451 }
452 
453 static void
454 parse_cfg(struct ng_pipe_hookcfg *current, struct ng_pipe_hookcfg *new,
455 	struct hookinfo *hinfo, priv_p priv)
456 {
457 
458 	if (new->ber == -1) {
459 		current->ber = 0;
460 		if (hinfo->ber_p) {
461 			free(hinfo->ber_p, M_NG_PIPE);
462 			hinfo->ber_p = NULL;
463 		}
464 	} else if (new->ber >= 1 && new->ber <= 1000000000000) {
465 		static const uint64_t one = 0x1000000000000; /* = 2^48 */
466 		uint64_t p0, p;
467 		uint32_t fsize, i;
468 
469 		if (hinfo->ber_p == NULL)
470 			hinfo->ber_p =
471 			    malloc((MAX_FSIZE + MAX_OHSIZE) * sizeof(uint64_t),
472 			    M_NG_PIPE, M_WAITOK);
473 		current->ber = new->ber;
474 
475 		/*
476 		 * For given BER and each frame size N (in bytes) calculate
477 		 * the probability P_OK that the frame is clean:
478 		 *
479 		 * P_OK(BER,N) = (1 - 1/BER)^(N*8)
480 		 *
481 		 * We use a 64-bit fixed-point format with decimal point
482 		 * positioned between bits 47 and 48.
483 		 */
484 		p0 = one - one / new->ber;
485 		p = one;
486 		for (fsize = 0; fsize < MAX_FSIZE + MAX_OHSIZE; fsize++) {
487 			hinfo->ber_p[fsize] = p;
488 			for (i = 0; i < 8; i++)
489 				p = (p * (p0 & 0xffff) >> 48) +
490 				    (p * ((p0 >> 16) & 0xffff) >> 32) +
491 				    (p * (p0 >> 32) >> 16);
492 		}
493 	}
494 
495 	if (new->qin_size_limit == -1)
496 		current->qin_size_limit = 0;
497 	else if (new->qin_size_limit >= 5)
498 		current->qin_size_limit = new->qin_size_limit;
499 
500 	if (new->qout_size_limit == -1)
501 		current->qout_size_limit = 0;
502 	else if (new->qout_size_limit >= 5)
503 		current->qout_size_limit = new->qout_size_limit;
504 
505 	if (new->duplicate == -1)
506 		current->duplicate = 0;
507 	else if (new->duplicate > 0 && new->duplicate <= 50)
508 		current->duplicate = new->duplicate;
509 
510 	if (new->fifo) {
511 		current->fifo = 1;
512 		current->wfq = 0;
513 		current->drr = 0;
514 	}
515 
516 	if (new->wfq) {
517 		current->fifo = 0;
518 		current->wfq = 1;
519 		current->drr = 0;
520 	}
521 
522 	if (new->drr) {
523 		current->fifo = 0;
524 		current->wfq = 0;
525 		/* DRR quantum */
526 		if (new->drr >= 32)
527 			current->drr = new->drr;
528 		else
529 			current->drr = 2048;		/* default quantum */
530 	}
531 
532 	if (new->droptail) {
533 		current->droptail = 1;
534 		current->drophead = 0;
535 	}
536 
537 	if (new->drophead) {
538 		current->droptail = 0;
539 		current->drophead = 1;
540 	}
541 
542 	if (new->bandwidth == -1) {
543 		current->bandwidth = 0;
544 		current->fifo = 1;
545 		current->wfq = 0;
546 		current->drr = 0;
547 	} else if (new->bandwidth >= 100 && new->bandwidth <= 1000000000)
548 		current->bandwidth = new->bandwidth;
549 
550 	if (current->bandwidth | priv->delay |
551 	    current->duplicate | current->ber)
552 		hinfo->noqueue = 0;
553 	else
554 		hinfo->noqueue = 1;
555 }
556 
557 /*
558  * Compute a hash signature for a packet. This function suffers from the
559  * NIH sindrome, so probably it would be wise to look around what other
560  * folks have found out to be a good and efficient IP hash function...
561  */
562 static int
563 ip_hash(struct mbuf *m, int offset)
564 {
565 	u_int64_t i;
566 	struct ip *ip = (struct ip *)(mtod(m, u_char *) + offset);
567 
568 	if (m->m_len < sizeof(struct ip) + offset ||
569 	    ip->ip_v != 4 || ip->ip_hl << 2 != sizeof(struct ip))
570 		return 0;
571 
572 	i = ((u_int64_t) ip->ip_src.s_addr ^
573 	    ((u_int64_t) ip->ip_src.s_addr << 13) ^
574 	    ((u_int64_t) ip->ip_dst.s_addr << 7) ^
575 	    ((u_int64_t) ip->ip_dst.s_addr << 19));
576 	return (i ^ (i >> 32));
577 }
578 
579 /*
580  * Receive data on a hook - both in upstream and downstream direction.
581  * We put the frame on the inbound queue, and try to initiate dequeuing
582  * sequence immediately. If inbound queue is full, discard one frame
583  * depending on dropping policy (from the head or from the tail of the
584  * queue).
585  */
586 static int
587 ngp_rcvdata(hook_p hook, item_p item)
588 {
589 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
590 	const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
591 	struct timeval uuptime;
592 	struct timeval *now = &uuptime;
593 	struct ngp_fifo *ngp_f = NULL, *ngp_f1;
594 	struct ngp_hdr *ngp_h = NULL;
595 	struct mbuf *m;
596 	int hash, plen;
597 	int error = 0;
598 
599 	/*
600 	 * Shortcut from inbound to outbound hook when neither of
601 	 * bandwidth, delay, BER or duplication probability is
602 	 * configured, nor we have queued frames to drain.
603 	 */
604 	if (hinfo->run.qin_frames == 0 && hinfo->run.qout_frames == 0 &&
605 	    hinfo->noqueue) {
606 		struct hookinfo *dest;
607 		if (hinfo == &priv->lower)
608 			dest = &priv->upper;
609 		else
610 			dest = &priv->lower;
611 
612 		/* Send the frame. */
613 		plen = NGI_M(item)->m_pkthdr.len;
614 		NG_FWD_ITEM_HOOK(error, item, dest->hook);
615 
616 		/* Update stats. */
617 		if (error) {
618 			hinfo->stats.out_disc_frames++;
619 			hinfo->stats.out_disc_octets += plen;
620 		} else {
621 			hinfo->stats.fwd_frames++;
622 			hinfo->stats.fwd_octets += plen;
623 		}
624 
625 		return (error);
626 	}
627 
628 	microuptime(now);
629 
630 	/*
631 	 * If this was an empty queue, update service deadline time.
632 	 */
633 	if (hinfo->run.qin_frames == 0) {
634 		struct timeval *when = &hinfo->qin_utime;
635 		if (when->tv_sec < now->tv_sec || (when->tv_sec == now->tv_sec
636 		    && when->tv_usec < now->tv_usec)) {
637 			when->tv_sec = now->tv_sec;
638 			when->tv_usec = now->tv_usec;
639 		}
640 	}
641 
642 	/* Populate the packet header */
643 	ngp_h = uma_zalloc(ngp_zone, M_NOWAIT);
644 	KASSERT((ngp_h != NULL), ("ngp_h zalloc failed (1)"));
645 	NGI_GET_M(item, m);
646 	KASSERT(m != NULL, ("NGI_GET_M failed"));
647 	ngp_h->m = m;
648 	NG_FREE_ITEM(item);
649 
650 	if (hinfo->cfg.fifo)
651 		hash = 0;	/* all packets go into a single FIFO queue */
652 	else
653 		hash = ip_hash(m, priv->header_offset);
654 
655 	/* Find the appropriate FIFO queue for the packet and enqueue it*/
656 	TAILQ_FOREACH(ngp_f, &hinfo->fifo_head, fifo_le)
657 		if (hash == ngp_f->hash)
658 			break;
659 	if (ngp_f == NULL) {
660 		ngp_f = uma_zalloc(ngp_zone, M_NOWAIT);
661 		KASSERT(ngp_h != NULL, ("ngp_h zalloc failed (2)"));
662 		TAILQ_INIT(&ngp_f->packet_head);
663 		ngp_f->hash = hash;
664 		ngp_f->packets = 1;
665 		ngp_f->rr_deficit = hinfo->cfg.drr;	/* DRR quantum */
666 		hinfo->run.fifo_queues++;
667 		TAILQ_INSERT_TAIL(&ngp_f->packet_head, ngp_h, ngp_link);
668 		FIFO_VTIME_SORT(m->m_pkthdr.len);
669 	} else {
670 		TAILQ_INSERT_TAIL(&ngp_f->packet_head, ngp_h, ngp_link);
671 		ngp_f->packets++;
672 	}
673 	hinfo->run.qin_frames++;
674 	hinfo->run.qin_octets += m->m_pkthdr.len;
675 
676 	/* Discard a frame if inbound queue limit has been reached */
677 	if (hinfo->run.qin_frames > hinfo->cfg.qin_size_limit) {
678 		struct mbuf *m1;
679 		int longest = 0;
680 
681 		/* Find the longest queue */
682 		TAILQ_FOREACH(ngp_f1, &hinfo->fifo_head, fifo_le)
683 			if (ngp_f1->packets > longest) {
684 				longest = ngp_f1->packets;
685 				ngp_f = ngp_f1;
686 			}
687 
688 		/* Drop a frame from the queue head/tail, depending on cfg */
689 		if (hinfo->cfg.drophead)
690 			ngp_h = TAILQ_FIRST(&ngp_f->packet_head);
691 		else
692 			ngp_h = TAILQ_LAST(&ngp_f->packet_head, p_head);
693 		TAILQ_REMOVE(&ngp_f->packet_head, ngp_h, ngp_link);
694 		m1 = ngp_h->m;
695 		uma_zfree(ngp_zone, ngp_h);
696 		hinfo->run.qin_octets -= m1->m_pkthdr.len;
697 		hinfo->stats.in_disc_octets += m1->m_pkthdr.len;
698 		m_freem(m1);
699 		if (--(ngp_f->packets) == 0) {
700 			TAILQ_REMOVE(&hinfo->fifo_head, ngp_f, fifo_le);
701 			uma_zfree(ngp_zone, ngp_f);
702 			hinfo->run.fifo_queues--;
703 		}
704 		hinfo->run.qin_frames--;
705 		hinfo->stats.in_disc_frames++;
706 	}
707 
708 	/*
709 	 * Try to start the dequeuing process immediately.
710 	 */
711 	pipe_dequeue(hinfo, now);
712 
713 	return (0);
714 }
715 
716 /*
717  * Dequeueing sequence - we basically do the following:
718  *  1) Try to extract the frame from the inbound (bandwidth) queue;
719  *  2) In accordance to BER specified, discard the frame randomly;
720  *  3) If the frame survives BER, prepend it with delay info and move it
721  *     to outbound (delay) queue;
722  *  4) Loop to 2) until bandwidth quota for this timeslice is reached, or
723  *     inbound queue is flushed completely;
724  *  5) Dequeue frames from the outbound queue and send them downstream until
725  *     outbound queue is flushed completely, or the next frame in the queue
726  *     is not due to be dequeued yet
727  */
728 static void
729 pipe_dequeue(struct hookinfo *hinfo, struct timeval *now) {
730 	static uint64_t rand, oldrand;
731 	const node_p node = NG_HOOK_NODE(hinfo->hook);
732 	const priv_p priv = NG_NODE_PRIVATE(node);
733 	struct hookinfo *dest;
734 	struct ngp_fifo *ngp_f, *ngp_f1;
735 	struct ngp_hdr *ngp_h;
736 	struct timeval *when;
737 	struct mbuf *m;
738 	int plen, error = 0;
739 
740 	/* Which one is the destination hook? */
741 	if (hinfo == &priv->lower)
742 		dest = &priv->upper;
743 	else
744 		dest = &priv->lower;
745 
746 	/* Bandwidth queue processing */
747 	while ((ngp_f = TAILQ_FIRST(&hinfo->fifo_head))) {
748 		when = &hinfo->qin_utime;
749 		if (when->tv_sec > now->tv_sec || (when->tv_sec == now->tv_sec
750 		    && when->tv_usec > now->tv_usec))
751 			break;
752 
753 		ngp_h = TAILQ_FIRST(&ngp_f->packet_head);
754 		m = ngp_h->m;
755 
756 		/* Deficit Round Robin (DRR) processing */
757 		if (hinfo->cfg.drr) {
758 			if (ngp_f->rr_deficit >= m->m_pkthdr.len) {
759 				ngp_f->rr_deficit -= m->m_pkthdr.len;
760 			} else {
761 				ngp_f->rr_deficit += hinfo->cfg.drr;
762 				TAILQ_REMOVE(&hinfo->fifo_head, ngp_f, fifo_le);
763 				TAILQ_INSERT_TAIL(&hinfo->fifo_head,
764 				    ngp_f, fifo_le);
765 				continue;
766 			}
767 		}
768 
769 		/*
770 		 * Either create a duplicate and pass it on, or dequeue
771 		 * the original packet...
772 		 */
773 		if (hinfo->cfg.duplicate &&
774 		    random() % 100 <= hinfo->cfg.duplicate) {
775 			ngp_h = uma_zalloc(ngp_zone, M_NOWAIT);
776 			KASSERT(ngp_h != NULL, ("ngp_h zalloc failed (3)"));
777 			m = m_dup(m, M_NOWAIT);
778 			KASSERT(m != NULL, ("m_dup failed"));
779 			ngp_h->m = m;
780 		} else {
781 			TAILQ_REMOVE(&ngp_f->packet_head, ngp_h, ngp_link);
782 			hinfo->run.qin_frames--;
783 			hinfo->run.qin_octets -= m->m_pkthdr.len;
784 			ngp_f->packets--;
785 		}
786 
787 		/* Calculate the serialization delay */
788 		if (hinfo->cfg.bandwidth) {
789 			hinfo->qin_utime.tv_usec +=
790 			    ((uint64_t) m->m_pkthdr.len + priv->overhead ) *
791 			    8000000 / hinfo->cfg.bandwidth;
792 			hinfo->qin_utime.tv_sec +=
793 			    hinfo->qin_utime.tv_usec / 1000000;
794 			hinfo->qin_utime.tv_usec =
795 			    hinfo->qin_utime.tv_usec % 1000000;
796 		}
797 		when = &ngp_h->when;
798 		when->tv_sec = hinfo->qin_utime.tv_sec;
799 		when->tv_usec = hinfo->qin_utime.tv_usec;
800 
801 		/* Sort / rearrange inbound queues */
802 		if (ngp_f->packets) {
803 			if (hinfo->cfg.wfq) {
804 				TAILQ_REMOVE(&hinfo->fifo_head, ngp_f, fifo_le);
805 				FIFO_VTIME_SORT(TAILQ_FIRST(
806 				    &ngp_f->packet_head)->m->m_pkthdr.len)
807 			}
808 		} else {
809 			TAILQ_REMOVE(&hinfo->fifo_head, ngp_f, fifo_le);
810 			uma_zfree(ngp_zone, ngp_f);
811 			hinfo->run.fifo_queues--;
812 		}
813 
814 		/* Randomly discard the frame, according to BER setting */
815 		if (hinfo->cfg.ber) {
816 			oldrand = rand;
817 			rand = random();
818 			if (((oldrand ^ rand) << 17) >=
819 			    hinfo->ber_p[priv->overhead + m->m_pkthdr.len]) {
820 				hinfo->stats.out_disc_frames++;
821 				hinfo->stats.out_disc_octets += m->m_pkthdr.len;
822 				uma_zfree(ngp_zone, ngp_h);
823 				m_freem(m);
824 				continue;
825 			}
826 		}
827 
828 		/* Discard frame if outbound queue size limit exceeded */
829 		if (hinfo->cfg.qout_size_limit &&
830 		    hinfo->run.qout_frames>=hinfo->cfg.qout_size_limit) {
831 			hinfo->stats.out_disc_frames++;
832 			hinfo->stats.out_disc_octets += m->m_pkthdr.len;
833 			uma_zfree(ngp_zone, ngp_h);
834 			m_freem(m);
835 			continue;
836 		}
837 
838 		/* Calculate the propagation delay */
839 		when->tv_usec += priv->delay;
840 		when->tv_sec += when->tv_usec / 1000000;
841 		when->tv_usec = when->tv_usec % 1000000;
842 
843 		/* Put the frame into the delay queue */
844 		TAILQ_INSERT_TAIL(&hinfo->qout_head, ngp_h, ngp_link);
845 		hinfo->run.qout_frames++;
846 		hinfo->run.qout_octets += m->m_pkthdr.len;
847 	}
848 
849 	/* Delay queue processing */
850 	while ((ngp_h = TAILQ_FIRST(&hinfo->qout_head))) {
851 		when = &ngp_h->when;
852 		m = ngp_h->m;
853 		if (when->tv_sec > now->tv_sec ||
854 		    (when->tv_sec == now->tv_sec &&
855 		    when->tv_usec > now->tv_usec))
856 			break;
857 
858 		/* Update outbound queue stats */
859 		plen = m->m_pkthdr.len;
860 		hinfo->run.qout_frames--;
861 		hinfo->run.qout_octets -= plen;
862 
863 		/* Dequeue the packet from qout */
864 		TAILQ_REMOVE(&hinfo->qout_head, ngp_h, ngp_link);
865 		uma_zfree(ngp_zone, ngp_h);
866 
867 		NG_SEND_DATA(error, dest->hook, m, meta);
868 		if (error) {
869 			hinfo->stats.out_disc_frames++;
870 			hinfo->stats.out_disc_octets += plen;
871 		} else {
872 			hinfo->stats.fwd_frames++;
873 			hinfo->stats.fwd_octets += plen;
874 		}
875 	}
876 
877 	if ((hinfo->run.qin_frames != 0 || hinfo->run.qout_frames != 0) &&
878 	    !priv->timer_scheduled) {
879 		ng_callout(&priv->timer, node, NULL, 1, ngp_callout, NULL, 0);
880 		priv->timer_scheduled = 1;
881 	}
882 }
883 
884 /*
885  * This routine is called on every clock tick.  We poll connected hooks
886  * for queued frames by calling pipe_dequeue().
887  */
888 static void
889 ngp_callout(node_p node, hook_p hook, void *arg1, int arg2)
890 {
891 	const priv_p priv = NG_NODE_PRIVATE(node);
892 	struct timeval now;
893 
894 	priv->timer_scheduled = 0;
895 	microuptime(&now);
896 	if (priv->upper.hook != NULL)
897 		pipe_dequeue(&priv->upper, &now);
898 	if (priv->lower.hook != NULL)
899 		pipe_dequeue(&priv->lower, &now);
900 }
901 
902 /*
903  * Shutdown processing
904  *
905  * This is tricky. If we have both a lower and upper hook, then we
906  * probably want to extricate ourselves and leave the two peers
907  * still linked to each other. Otherwise we should just shut down as
908  * a normal node would.
909  */
910 static int
911 ngp_shutdown(node_p node)
912 {
913 	const priv_p priv = NG_NODE_PRIVATE(node);
914 
915 	if (priv->timer_scheduled)
916 		ng_uncallout(&priv->timer, node);
917 	if (priv->lower.hook && priv->upper.hook)
918 		ng_bypass(priv->lower.hook, priv->upper.hook);
919 	else {
920 		if (priv->upper.hook != NULL)
921 			ng_rmhook_self(priv->upper.hook);
922 		if (priv->lower.hook != NULL)
923 			ng_rmhook_self(priv->lower.hook);
924 	}
925 	NG_NODE_UNREF(node);
926 	free(priv, M_NG_PIPE);
927 	return (0);
928 }
929 
930 /*
931  * Hook disconnection
932  */
933 static int
934 ngp_disconnect(hook_p hook)
935 {
936 	struct hookinfo *const hinfo = NG_HOOK_PRIVATE(hook);
937 	struct ngp_fifo *ngp_f;
938 	struct ngp_hdr *ngp_h;
939 
940 	KASSERT(hinfo != NULL, ("%s: null info", __FUNCTION__));
941 	hinfo->hook = NULL;
942 
943 	/* Flush all fifo queues associated with the hook */
944 	while ((ngp_f = TAILQ_FIRST(&hinfo->fifo_head))) {
945 		while ((ngp_h = TAILQ_FIRST(&ngp_f->packet_head))) {
946 			TAILQ_REMOVE(&ngp_f->packet_head, ngp_h, ngp_link);
947 			m_freem(ngp_h->m);
948 			uma_zfree(ngp_zone, ngp_h);
949 		}
950 		TAILQ_REMOVE(&hinfo->fifo_head, ngp_f, fifo_le);
951 		uma_zfree(ngp_zone, ngp_f);
952 	}
953 
954 	/* Flush the delay queue */
955 	while ((ngp_h = TAILQ_FIRST(&hinfo->qout_head))) {
956 		TAILQ_REMOVE(&hinfo->qout_head, ngp_h, ngp_link);
957 		m_freem(ngp_h->m);
958 		uma_zfree(ngp_zone, ngp_h);
959 	}
960 
961 	/* Release the packet loss probability table (BER) */
962 	if (hinfo->ber_p)
963 		free(hinfo->ber_p, M_NG_PIPE);
964 
965 	return (0);
966 }
967 
968 static int
969 ngp_modevent(module_t mod, int type, void *unused)
970 {
971 	int error = 0;
972 
973 	switch (type) {
974 	case MOD_LOAD:
975 		ngp_zone = uma_zcreate("ng_pipe", max(sizeof(struct ngp_hdr),
976 		    sizeof (struct ngp_fifo)), NULL, NULL, NULL, NULL,
977 		    UMA_ALIGN_PTR, 0);
978 		if (ngp_zone == NULL)
979 			panic("ng_pipe: couldn't allocate descriptor zone");
980 		break;
981 	case MOD_UNLOAD:
982 		uma_zdestroy(ngp_zone);
983 		break;
984 	default:
985 		error = EOPNOTSUPP;
986 		break;
987 	}
988 
989 	return (error);
990 }
991