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      1 /*	$NetBSD: altq_fifoq.c,v 1.19 2025/01/08 13:00:04 joe Exp $	*/
      2 /*	$KAME: altq_fifoq.c,v 1.12 2003/07/10 12:07:48 kjc Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 1997-2002
      6  *	Sony Computer Science Laboratories Inc.  All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY SONY CSL AND CONTRIBUTORS ``AS IS'' AND
     18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     20  * ARE DISCLAIMED.  IN NO EVENT SHALL SONY CSL OR CONTRIBUTORS BE LIABLE
     21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     27  * SUCH DAMAGE.
     28  */
     29 
     30 #include <sys/cdefs.h>
     31 __KERNEL_RCSID(0, "$NetBSD: altq_fifoq.c,v 1.19 2025/01/08 13:00:04 joe Exp $");
     32 
     33 #ifdef _KERNEL_OPT
     34 #include "opt_altq.h"
     35 #endif
     36 
     37 #ifdef ALTQ_FIFOQ  /* fifoq is enabled by ALTQ_FIFOQ option in opt_altq.h */
     38 
     39 /*
     40  * FIFOQ is an altq sample implementation.  There will be little
     41  * need to use FIFOQ as an alternative queueing scheme.
     42  * But this code is provided as a template for those who want to
     43  * write their own queueing schemes.
     44  */
     45 
     46 #include <sys/param.h>
     47 #include <sys/malloc.h>
     48 #include <sys/mbuf.h>
     49 #include <sys/socket.h>
     50 #include <sys/sockio.h>
     51 #include <sys/systm.h>
     52 #include <sys/proc.h>
     53 #include <sys/errno.h>
     54 #include <sys/kernel.h>
     55 #include <sys/kauth.h>
     56 
     57 #include <net/if.h>
     58 #include <net/if_types.h>
     59 #include <netinet/in.h>
     60 
     61 #include <altq/altq.h>
     62 #include <altq/altq_conf.h>
     63 #include <altq/altq_fifoq.h>
     64 
     65 #ifdef ALTQ3_COMPAT
     66 
     67 #define	FIFOQ_STATS	/* collect statistics */
     68 
     69 /* fifoq_list keeps all fifoq_state_t's allocated. */
     70 static fifoq_state_t *fifoq_list = NULL;
     71 
     72 /* internal function prototypes */
     73 static int		fifoq_enqueue(struct ifaltq *, struct mbuf *);
     74 static struct mbuf 	*fifoq_dequeue(struct ifaltq *, int);
     75 static int 		fifoq_detach(fifoq_state_t *);
     76 static int		fifoq_request(struct ifaltq *, int, void *);
     77 static void 		fifoq_purge(fifoq_state_t *);
     78 
     79 /*
     80  * fifoq device interface
     81  */
     82 altqdev_decl(fifoq);
     83 
     84 int
     85 fifoqopen(dev_t dev, int flag, int fmt,
     86     struct lwp *l)
     87 {
     88 	/* everything will be done when the queueing scheme is attached. */
     89 	return 0;
     90 }
     91 
     92 /*
     93  * there are 2 ways to act on close.
     94  *   detach-all-on-close:
     95  *	use for the daemon style approach.  if the daemon dies, all the
     96  *	resource will be released.
     97  *   no-action-on-close:
     98  *	use for the command style approach.  (e.g.  fifoq on/off)
     99  *
    100  * note: close is called not on every close but when the last reference
    101  *       is removed (only once with multiple simultaneous references.)
    102  */
    103 int
    104 fifoqclose(dev_t dev, int flag, int fmt,
    105     struct lwp *l)
    106 {
    107 	fifoq_state_t *q;
    108 	int err, error = 0;
    109 
    110 	while ((q = fifoq_list) != NULL) {
    111 		/* destroy all */
    112 		err = fifoq_detach(q);
    113 		if (err != 0 && error == 0)
    114 			error = err;
    115 	}
    116 
    117 	return error;
    118 }
    119 
    120 int
    121 fifoqioctl(dev_t dev, ioctlcmd_t cmd, void *addr, int flag,
    122     struct lwp *l)
    123 {
    124 	fifoq_state_t *q;
    125 	struct fifoq_interface *ifacep;
    126 	struct ifnet *ifp;
    127 	int	error = 0;
    128 
    129 	/* check super-user privilege */
    130 	switch (cmd) {
    131 	case FIFOQ_GETSTATS:
    132 		break;
    133 	default:
    134 		if ((error = kauth_authorize_network(l->l_cred,
    135 		    KAUTH_NETWORK_ALTQ, KAUTH_REQ_NETWORK_ALTQ_FIFOQ, NULL,
    136 		    NULL, NULL)) != 0)
    137 			return error;
    138 		break;
    139 	}
    140 
    141 	switch (cmd) {
    142 	case FIFOQ_ENABLE:
    143 		ifacep = (struct fifoq_interface *)addr;
    144 		if ((q = altq_lookup(ifacep->fifoq_ifname, ALTQT_FIFOQ))
    145 		    == NULL) {
    146 			error = EBADF;
    147 			break;
    148 		}
    149 		error = altq_enable(q->q_ifq);
    150 		break;
    151 
    152 	case FIFOQ_DISABLE:
    153 		ifacep = (struct fifoq_interface *)addr;
    154 		if ((q = altq_lookup(ifacep->fifoq_ifname, ALTQT_FIFOQ))
    155 		    == NULL) {
    156 			error = EBADF;
    157 			break;
    158 		}
    159 		error = altq_disable(q->q_ifq);
    160 		break;
    161 
    162 	case FIFOQ_IF_ATTACH:
    163 		ifp = ifunit(((struct fifoq_interface *)addr)->fifoq_ifname);
    164 		if (ifp == NULL) {
    165 			error = ENXIO;
    166 			break;
    167 		}
    168 
    169 		/* allocate and initialize fifoq_state_t */
    170 		q = malloc(sizeof(fifoq_state_t), M_DEVBUF, M_WAITOK|M_ZERO);
    171 		if (q == NULL) {
    172 			error = ENOMEM;
    173 			break;
    174 		}
    175 
    176 		q->q_ifq = &ifp->if_snd;
    177 		q->q_head = q->q_tail = NULL;
    178 		q->q_len = 0;
    179 		q->q_limit = FIFOQ_LIMIT;
    180 
    181 		/*
    182 		 * set FIFOQ to this ifnet structure.
    183 		 */
    184 		error = altq_attach(q->q_ifq, ALTQT_FIFOQ, q,
    185 				    fifoq_enqueue, fifoq_dequeue, fifoq_request,
    186 				    NULL, NULL);
    187 		if (error) {
    188 			free(q, M_DEVBUF);
    189 			break;
    190 		}
    191 
    192 		/* add this state to the fifoq list */
    193 		q->q_next = fifoq_list;
    194 		fifoq_list = q;
    195 		break;
    196 
    197 	case FIFOQ_IF_DETACH:
    198 		ifacep = (struct fifoq_interface *)addr;
    199 		if ((q = altq_lookup(ifacep->fifoq_ifname, ALTQT_FIFOQ))
    200 		    == NULL) {
    201 			error = EBADF;
    202 			break;
    203 		}
    204 		error = fifoq_detach(q);
    205 		break;
    206 
    207 	case FIFOQ_GETSTATS:
    208 		do {
    209 			struct fifoq_getstats *q_stats;
    210 
    211 			q_stats = (struct fifoq_getstats *)addr;
    212 			if ((q = altq_lookup(q_stats->iface.fifoq_ifname,
    213 					     ALTQT_FIFOQ)) == NULL) {
    214 				error = EBADF;
    215 				break;
    216 			}
    217 
    218 			q_stats->q_len		= q->q_len;
    219 			q_stats->q_limit 	= q->q_limit;
    220 			q_stats->xmit_cnt	= q->q_stats.xmit_cnt;
    221 			q_stats->drop_cnt 	= q->q_stats.drop_cnt;
    222 			q_stats->period   	= q->q_stats.period;
    223 		} while (/*CONSTCOND*/ 0);
    224 		break;
    225 
    226 	case FIFOQ_CONFIG:
    227 		do {
    228 			struct fifoq_conf *fc;
    229 			int limit;
    230 
    231 			fc = (struct fifoq_conf *)addr;
    232 			if ((q = altq_lookup(fc->iface.fifoq_ifname,
    233 					     ALTQT_FIFOQ)) == NULL) {
    234 				error = EBADF;
    235 				break;
    236 			}
    237 			limit = fc->fifoq_limit;
    238 			if (limit < 0)
    239 				limit = 0;
    240 			q->q_limit = limit;
    241 			fc->fifoq_limit = limit;
    242 		} while (/*CONSTCOND*/ 0);
    243 		break;
    244 
    245 	default:
    246 		error = EINVAL;
    247 		break;
    248 	}
    249 	return error;
    250 }
    251 
    252 /*
    253  * fifoq support routines
    254  */
    255 
    256 /*
    257  * enqueue routine:
    258  *
    259  *	returns: 0 when successfully queued.
    260  *		 ENOBUFS when drop occurs.
    261  */
    262 static int
    263 fifoq_enqueue(struct ifaltq *ifq, struct mbuf *m)
    264 {
    265 	fifoq_state_t *q = (fifoq_state_t *)ifq->altq_disc;
    266 
    267 	/* if the queue is full, drop the incoming packet(drop-tail) */
    268 	if (q->q_len >= q->q_limit) {
    269 #ifdef FIFOQ_STATS
    270 		PKTCNTR_ADD(&q->q_stats.drop_cnt, m_pktlen(m));
    271 #endif
    272 		m_freem(m);
    273 		return ENOBUFS;
    274 	}
    275 
    276 	/* enqueue the packet at the taile of the queue */
    277 	m->m_nextpkt = NULL;
    278 	if (q->q_tail == NULL)
    279 		q->q_head = m;
    280 	else
    281 		q->q_tail->m_nextpkt = m;
    282 	q->q_tail = m;
    283 	q->q_len++;
    284 	ifq->ifq_len++;
    285 	return 0;
    286 }
    287 
    288 /*
    289  * dequeue routine:
    290  *	must be called in splnet.
    291  *
    292  *	returns: mbuf dequeued.
    293  *		 NULL when no packet is available in the queue.
    294  */
    295 /*
    296  * ALTDQ_PEEK is provided for drivers which need to know the next packet
    297  * to send in advance.
    298  * when ALTDQ_PEEK is specified, the next packet to be dequeued is
    299  * returned without dequeueing the packet.
    300  * when ALTDQ_DEQUEUE is called *immediately after* an ALTDQ_PEEK
    301  * operation, the same packet should be returned.
    302  */
    303 static struct mbuf *
    304 fifoq_dequeue(struct ifaltq *ifq, int op)
    305 {
    306 	fifoq_state_t *q = (fifoq_state_t *)ifq->altq_disc;
    307 	struct mbuf *m = NULL;
    308 
    309 	if (op == ALTDQ_POLL)
    310 		return (q->q_head);
    311 
    312 	if ((m = q->q_head) == NULL)
    313 		return NULL;
    314 
    315 	if ((q->q_head = m->m_nextpkt) == NULL)
    316 		q->q_tail = NULL;
    317 	m->m_nextpkt = NULL;
    318 	q->q_len--;
    319 	ifq->ifq_len--;
    320 #ifdef FIFOQ_STATS
    321 	PKTCNTR_ADD(&q->q_stats.xmit_cnt, m_pktlen(m));
    322 	if (q->q_len == 0)
    323 		q->q_stats.period++;
    324 #endif
    325 	return m;
    326 }
    327 
    328 static int
    329 fifoq_request(struct ifaltq *ifq, int req, void *arg)
    330 {
    331 	fifoq_state_t *q = (fifoq_state_t *)ifq->altq_disc;
    332 
    333 	switch (req) {
    334 	case ALTRQ_PURGE:
    335 		fifoq_purge(q);
    336 		break;
    337 	}
    338 	return 0;
    339 }
    340 
    341 
    342 static int
    343 fifoq_detach(fifoq_state_t *q)
    344 {
    345 	fifoq_state_t *tmp;
    346 	int error = 0;
    347 
    348 	if (ALTQ_IS_ENABLED(q->q_ifq))
    349 		altq_disable(q->q_ifq);
    350 
    351 	fifoq_purge(q);
    352 
    353 	if ((error = altq_detach(q->q_ifq)))
    354 		return error;
    355 
    356 	if (fifoq_list == q)
    357 		fifoq_list = q->q_next;
    358 	else {
    359 		for (tmp = fifoq_list; tmp != NULL; tmp = tmp->q_next)
    360 			if (tmp->q_next == q) {
    361 				tmp->q_next = q->q_next;
    362 				break;
    363 			}
    364 		if (tmp == NULL)
    365 			printf("fifoq_detach: no state in fifoq_list!\n");
    366 	}
    367 
    368 	free(q, M_DEVBUF);
    369 	return error;
    370 }
    371 
    372 /*
    373  * fifoq_purge
    374  * should be called in splnet or after disabling the fifoq.
    375  */
    376 static void
    377 fifoq_purge(fifoq_state_t *q)
    378 {
    379 	struct mbuf *m;
    380 
    381 	while ((m = q->q_head) != NULL) {
    382 		q->q_head = m->m_nextpkt;
    383 		m_freem(m);
    384 	}
    385 	q->q_tail = NULL;
    386 	q->q_len = 0;
    387 	if (ALTQ_IS_ENABLED(q->q_ifq))
    388 		q->q_ifq->ifq_len = 0;
    389 }
    390 
    391 #ifdef KLD_MODULE
    392 
    393 static struct altqsw fifoq_sw =
    394 	{"fifoq", fifoqopen, fifoqclose, fifoqioctl};
    395 
    396 ALTQ_MODULE(altq_fifoq, ALTQT_FIFOQ, &fifoq_sw);
    397 
    398 #endif /* KLD_MODULE */
    399 
    400 #endif /* ALTQ3_COMPAT */
    401 #endif /* ALTQ_FIFOQ */
    402