* Copyright (C) 1997-2002

/* $NetBSD: altq_blue.c,v 1.27 2025/01/08 13:00:04 joe Exp $ */
/* $KAME: altq_blue.c,v 1.15 2005/04/13 03:44:24 suz Exp $ */

/*
* Copyright (C) 1997-2002
* Sony Computer Science Laboratories Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY SONY CSL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL SONY CSL OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/*
* Copyright (c) 1990-1994 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Systems
* Engineering Group at Lawrence Berkeley Laboratory.
* 4. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: altq_blue.c,v 1.27 2025/01/08 13:00:04 joe Exp $");

#ifdef _KERNEL_OPT
#include "opt_altq.h"
#include "opt_inet.h"
#endif

#ifdef ALTQ_BLUE /* blue is enabled by ALTQ_BLUE option in opt_altq.h */

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/kauth.h>
#include <sys/cprng.h>

#include <net/if.h>
#include <net/if_types.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif

#include <altq/altq.h>
#include <altq/altq_conf.h>
#include <altq/altq_blue.h>

#ifdef ALTQ3_COMPAT
/*
* Blue is proposed and implemented by Wu-chang Feng <[email protected]>.
* more information on Blue is available from
* http://www.eecs.umich.edu/~wuchang/blue/
*/

/* fixed-point uses 12-bit decimal places */
#define FP_SHIFT 12 /* fixed-point shift */

#define BLUE_LIMIT 200 /* default max queue length */
#define BLUE_STATS /* collect statistics */

/* blue_list keeps all blue_state_t's allocated. */
static blue_queue_t *blue_list = NULL;

/* internal function prototypes */
static int blue_enqueue(struct ifaltq *, struct mbuf *);
static struct mbuf *blue_dequeue(struct ifaltq *, int);
static int drop_early(blue_t *);
static int mark_ecn(struct mbuf *, struct altq_pktattr *, int);
static int blue_detach(blue_queue_t *);
static int blue_request(struct ifaltq *, int, void *);

/*
* blue device interface
*/
altqdev_decl(blue);

int
blueopen(dev_t dev, int flag, int fmt,
struct lwp *l)
{
/* everything will be done when the queueing scheme is attached. */
return 0;
}

int
blueclose(dev_t dev, int flag, int fmt,
struct lwp *l)
{
blue_queue_t *rqp;
int err, error = 0;

while ((rqp = blue_list) != NULL) {
/* destroy all */
err = blue_detach(rqp);
if (err != 0 && error == 0)
error = err;
}

return error;
}

int
blueioctl(dev_t dev, ioctlcmd_t cmd, void *addr, int flag,
struct lwp *l)
{
blue_queue_t *rqp;
struct blue_interface *ifacep;
struct ifnet *ifp;
int error = 0;

/* check super-user privilege */
switch (cmd) {
case BLUE_GETSTATS:
break;
default:
if ((error = kauth_authorize_network(l->l_cred,
KAUTH_NETWORK_ALTQ, KAUTH_REQ_NETWORK_ALTQ_BLUE, NULL,
NULL, NULL)) != 0)
return (error);
break;
}

switch (cmd) {

case BLUE_ENABLE:
ifacep = (struct blue_interface *)addr;
if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
error = EBADF;
break;
}
error = altq_enable(rqp->rq_ifq);
break;

case BLUE_DISABLE:
ifacep = (struct blue_interface *)addr;
if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
error = EBADF;
break;
}
error = altq_disable(rqp->rq_ifq);
break;

case BLUE_IF_ATTACH:
ifp = ifunit(((struct blue_interface *)addr)->blue_ifname);
if (ifp == NULL) {
error = ENXIO;
break;
}

/* allocate and initialize blue_state_t */
rqp = malloc(sizeof(blue_queue_t), M_DEVBUF, M_WAITOK|M_ZERO);
if (rqp == NULL) {
error = ENOMEM;
break;
}

rqp->rq_q = malloc(sizeof(class_queue_t), M_DEVBUF,
M_WAITOK|M_ZERO);
if (rqp->rq_q == NULL) {
free(rqp, M_DEVBUF);
error = ENOMEM;
break;
}

rqp->rq_blue = malloc(sizeof(blue_t), M_DEVBUF,
M_WAITOK|M_ZERO);
if (rqp->rq_blue == NULL) {
free(rqp->rq_q, M_DEVBUF);
free(rqp, M_DEVBUF);
error = ENOMEM;
break;
}

rqp->rq_ifq = &ifp->if_snd;
qtail(rqp->rq_q) = NULL;
qlen(rqp->rq_q) = 0;
qlimit(rqp->rq_q) = BLUE_LIMIT;

/* default packet time: 1000 bytes / 10Mbps * 8 * 1000000 */
blue_init(rqp->rq_blue, 0, 800, 1000, 50000);

/*
* set BLUE to this ifnet structure.
*/
error = altq_attach(rqp->rq_ifq, ALTQT_BLUE, rqp,
blue_enqueue, blue_dequeue, blue_request,
NULL, NULL);
if (error) {
free(rqp->rq_blue, M_DEVBUF);
free(rqp->rq_q, M_DEVBUF);
free(rqp, M_DEVBUF);
break;
}

/* add this state to the blue list */
rqp->rq_next = blue_list;
blue_list = rqp;
break;

case BLUE_IF_DETACH:
ifacep = (struct blue_interface *)addr;
if ((rqp = altq_lookup(ifacep->blue_ifname, ALTQT_BLUE)) == NULL) {
error = EBADF;
break;
}
error = blue_detach(rqp);
break;

case BLUE_GETSTATS:
do {
struct blue_stats *q_stats;
blue_t *rp;

q_stats = (struct blue_stats *)addr;
if ((rqp = altq_lookup(q_stats->iface.blue_ifname,
ALTQT_BLUE)) == NULL) {
error = EBADF;
break;
}

q_stats->q_len = qlen(rqp->rq_q);
q_stats->q_limit = qlimit(rqp->rq_q);

rp = rqp->rq_blue;
q_stats->q_pmark = rp->blue_pmark;
q_stats->xmit_packets = rp->blue_stats.xmit_packets;
q_stats->xmit_bytes = rp->blue_stats.xmit_bytes;
q_stats->drop_packets = rp->blue_stats.drop_packets;
q_stats->drop_bytes = rp->blue_stats.drop_bytes;
q_stats->drop_forced = rp->blue_stats.drop_forced;
q_stats->drop_unforced = rp->blue_stats.drop_unforced;
q_stats->marked_packets = rp->blue_stats.marked_packets;

} while (/*CONSTCOND*/ 0);
break;

case BLUE_CONFIG:
do {
struct blue_conf *fc;
int limit;

fc = (struct blue_conf *)addr;
if ((rqp = altq_lookup(fc->iface.blue_ifname,
ALTQT_BLUE)) == NULL) {
error = EBADF;
break;
}
limit = fc->blue_limit;
qlimit(rqp->rq_q) = limit;
fc->blue_limit = limit; /* write back the new value */
if (fc->blue_pkttime > 0)
rqp->rq_blue->blue_pkttime = fc->blue_pkttime;
if (fc->blue_max_pmark > 0)
rqp->rq_blue->blue_max_pmark = fc->blue_max_pmark;
if (fc->blue_hold_time > 0)
rqp->rq_blue->blue_hold_time = fc->blue_hold_time;
rqp->rq_blue->blue_flags = fc->blue_flags;

blue_init(rqp->rq_blue, rqp->rq_blue->blue_flags,
rqp->rq_blue->blue_pkttime,
rqp->rq_blue->blue_max_pmark,
rqp->rq_blue->blue_hold_time);
} while (/*CONSTCOND*/ 0);
break;

default:
error = EINVAL;
break;
}
return error;
}

static int
blue_detach(blue_queue_t *rqp)
{
blue_queue_t *tmp;
int error = 0;

if (ALTQ_IS_ENABLED(rqp->rq_ifq))
altq_disable(rqp->rq_ifq);

if ((error = altq_detach(rqp->rq_ifq)))
return (error);

if (blue_list == rqp)
blue_list = rqp->rq_next;
else {
for (tmp = blue_list; tmp != NULL; tmp = tmp->rq_next)
if (tmp->rq_next == rqp) {
tmp->rq_next = rqp->rq_next;
break;
}
if (tmp == NULL)
printf("blue_detach: no state found in blue_list!\n");
}

free(rqp->rq_q, M_DEVBUF);
free(rqp->rq_blue, M_DEVBUF);
free(rqp, M_DEVBUF);
return error;
}

/*
* blue support routines
*/

int
blue_init(blue_t *rp, int flags, int pkttime, int blue_max_pmark,
int blue_hold_time)
{
int npkts_per_sec;

rp->blue_idle = 1;
rp->blue_flags = flags;
rp->blue_pkttime = pkttime;
rp->blue_max_pmark = blue_max_pmark;
rp->blue_hold_time = blue_hold_time;
if (pkttime == 0)
rp->blue_pkttime = 1;

/* when the link is very slow, adjust blue parameters */
npkts_per_sec = 1000000 / rp->blue_pkttime;
if (npkts_per_sec < 50) {
}
else if (npkts_per_sec < 300) {
}

microtime(&rp->blue_last);
return 0;
}

/*
* enqueue routine:
*
* returns: 0 when successfully queued.
* ENOBUFS when drop occurs.
*/
static int
blue_enqueue(struct ifaltq *ifq, struct mbuf *m)
{
struct altq_pktattr pktattr;
blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;
int error = 0;

pktattr.pattr_class = m->m_pkthdr.pattr_class;
pktattr.pattr_af = m->m_pkthdr.pattr_af;
pktattr.pattr_hdr = m->m_pkthdr.pattr_hdr;

if (blue_addq(rqp->rq_blue, rqp->rq_q, m, &pktattr) == 0)
ifq->ifq_len++;
else
error = ENOBUFS;
return error;
}

#define DTYPE_NODROP 0 /* no drop */
#define DTYPE_FORCED 1 /* a "forced" drop */
#define DTYPE_EARLY 2 /* an "unforced" (early) drop */

int
blue_addq(blue_t *rp, class_queue_t *q, struct mbuf *m,
struct altq_pktattr *pktattr)
{
int droptype;

/*
* if we were idle, this is an enqueue onto an empty queue
* and we should decrement marking probability
*
*/
if (rp->blue_idle) {
struct timeval now;
int t;
rp->blue_idle = 0;
microtime(&now);
t = (now.tv_sec - rp->blue_last.tv_sec);
if ( t > 1) {
rp->blue_pmark = 1;
microtime(&rp->blue_last);
} else {
t = t * 1000000 + (now.tv_usec - rp->blue_last.tv_usec);
if (t > rp->blue_hold_time) {
rp->blue_pmark--;
if (rp->blue_pmark < 0) rp->blue_pmark = 0;
microtime(&rp->blue_last);
}
}
}

/* see if we drop early */
droptype = DTYPE_NODROP;
if (drop_early(rp) && qlen(q) > 1) {
/* mark or drop by blue */
if ((rp->blue_flags & BLUEF_ECN) &&
mark_ecn(m, pktattr, rp->blue_flags)) {
/* successfully marked. do not drop. */
#ifdef BLUE_STATS
rp->blue_stats.marked_packets++;
#endif
} else {
/* unforced drop by blue */
droptype = DTYPE_EARLY;
}
}

/*
* if the queue length hits the hard limit, it's a forced drop.
*/
if (droptype == DTYPE_NODROP && qlen(q) >= qlimit(q))
droptype = DTYPE_FORCED;

/* if successful or forced drop, enqueue this packet. */
if (droptype != DTYPE_EARLY)
_addq(q, m);

if (droptype != DTYPE_NODROP) {
if (droptype == DTYPE_EARLY) {
/* drop the incoming packet */
#ifdef BLUE_STATS
rp->blue_stats.drop_unforced++;
#endif
} else {
struct timeval now;
int t;
/* forced drop, select a victim packet in the queue. */
m = _getq_random(q);
microtime(&now);
t = (now.tv_sec - rp->blue_last.tv_sec);
t = t * 1000000 + (now.tv_usec - rp->blue_last.tv_usec);
if (t > rp->blue_hold_time) {
rp->blue_pmark += rp->blue_max_pmark >> 3;
if (rp->blue_pmark > rp->blue_max_pmark)
rp->blue_pmark = rp->blue_max_pmark;
microtime(&rp->blue_last);
}
#ifdef BLUE_STATS
rp->blue_stats.drop_forced++;
#endif
}
#ifdef BLUE_STATS
rp->blue_stats.drop_packets++;
rp->blue_stats.drop_bytes += m->m_pkthdr.len;
#endif
m_freem(m);
return -1;
}
/* successfully queued */
return 0;
}

/*
* early-drop probability is kept in blue_pmark
*
*/
static int
drop_early(blue_t *rp)
{
if ((cprng_fast32() % rp->blue_max_pmark) < rp->blue_pmark) {
/* drop or mark */
return 1;
}
/* no drop/mark */
return (0);
}

/*
* try to mark CE bit to the packet.
* returns 1 if successfully marked, 0 otherwise.
*/
static int
mark_ecn(struct mbuf *m, struct altq_pktattr *pktattr, int flags)
{
struct mbuf *m0;

if (pktattr == NULL ||
(pktattr->pattr_af != AF_INET && pktattr->pattr_af != AF_INET6))
return 0;

/* verify that pattr_hdr is within the mbuf data */
for (m0 = m; m0 != NULL; m0 = m0->m_next)
if (((char *)pktattr->pattr_hdr >= m0->m_data) &&
((char *)pktattr->pattr_hdr < m0->m_data + m0->m_len))
break;
if (m0 == NULL) {
/* ick, pattr_hdr is stale */
pktattr->pattr_af = AF_UNSPEC;
return 0;
}

switch (pktattr->pattr_af) {
case AF_INET:
if (flags & BLUEF_ECN4) {
struct ip *ip = (struct ip *)pktattr->pattr_hdr;
u_int8_t otos;
int sum;

if (ip->ip_v != 4)
return (0); /* version mismatch! */
if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT)
return (0); /* not-ECT */
if ((ip->ip_tos & IPTOS_ECN_MASK) == IPTOS_ECN_CE)
return (1); /* already marked */

/*
* ecn-capable but not marked,
* mark CE and update checksum
*/
otos = ip->ip_tos;
ip->ip_tos |= IPTOS_ECN_CE;
/*
* update checksum (from RFC1624)
* HC' = ~(~HC + ~m + m')
*/
sum = ~ntohs(ip->ip_sum) & 0xffff;
sum += (~otos & 0xffff) + ip->ip_tos;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16); /* add carry */
ip->ip_sum = htons(~sum & 0xffff);
return 1;
}
break;
#ifdef INET6
case AF_INET6:
if (flags & BLUEF_ECN6) {
struct ip6_hdr *ip6 = (struct ip6_hdr *)pktattr->pattr_hdr;
u_int32_t flowlabel;

flowlabel = ntohl(ip6->ip6_flow);
if ((flowlabel >> 28) != 6)
return (0); /* version mismatch! */
if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
(IPTOS_ECN_NOTECT << 20))
return (0); /* not-ECT */
if ((flowlabel & (IPTOS_ECN_MASK << 20)) ==
(IPTOS_ECN_CE << 20))
return (1); /* already marked */
/*
* ecn-capable but not marked, mark CE
*/
flowlabel |= (IPTOS_ECN_CE << 20);
ip6->ip6_flow = htonl(flowlabel);
return (1);
}
break;
#endif /* INET6 */
}

/* not marked */
return 0;
}

/*
* dequeue routine:
* must be called in splnet.
*
* returns: mbuf dequeued.
* NULL when no packet is available in the queue.
*/

static struct mbuf *
blue_dequeue(struct ifaltq * ifq, int op)
{
blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;
struct mbuf *m = NULL;

if (op == ALTDQ_POLL)
return (qhead(rqp->rq_q));

m = blue_getq(rqp->rq_blue, rqp->rq_q);
if (m != NULL)
ifq->ifq_len--;
return m;
}

struct mbuf *
blue_getq(blue_t *rp, class_queue_t *q)
{
struct mbuf *m;

if ((m = _getq(q)) == NULL) {
if (rp->blue_idle == 0) {
rp->blue_idle = 1;
microtime(&rp->blue_last);
}
return NULL;
}

rp->blue_idle = 0;
#ifdef BLUE_STATS
rp->blue_stats.xmit_packets++;
rp->blue_stats.xmit_bytes += m->m_pkthdr.len;
#endif
return m;
}

static int
blue_request(struct ifaltq *ifq, int req, void *arg)
{
blue_queue_t *rqp = (blue_queue_t *)ifq->altq_disc;

switch (req) {
case ALTRQ_PURGE:
_flushq(rqp->rq_q);
if (ALTQ_IS_ENABLED(ifq))
ifq->ifq_len = 0;
break;
}
return 0;
}

#ifdef KLD_MODULE

static struct altqsw blue_sw =
{"blue", blueopen, blueclose, blueioctl};

ALTQ_MODULE(altq_blue, ALTQT_BLUE, &blue_sw);

#endif /* KLD_MODULE */

#endif /* ALTQ3_COMPAT */
#endif /* ALTQ_BLUE */