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|
/* $OpenBSD: frag6.c,v 1.42 2012/01/24 19:08:46 bluhm Exp $ */
/* $KAME: frag6.c,v 1.40 2002/05/27 21:40:31 itojun Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* 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. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT 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 PROJECT 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/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet/in_systm.h> /* for ECN definitions */
#include <netinet/ip.h> /* for ECN definitions */
#include <dev/rndvar.h>
/*
* Define it to get a correct behavior on per-interface statistics.
* You will need to perform an extra routing table lookup, per fragment,
* to do it. This may, or may not be, a performance hit.
*/
#define IN6_IFSTAT_STRICT
void frag6_freef(struct ip6q *);
static int ip6q_locked;
u_int frag6_nfragpackets;
u_int frag6_nfrags;
TAILQ_HEAD(ip6q_head, ip6q) frag6_queue; /* ip6 reassemble queue */
static __inline int ip6q_lock_try(void);
static __inline void ip6q_unlock(void);
static __inline int
ip6q_lock_try()
{
int s;
/* Use splvm() due to mbuf allocation. */
s = splvm();
if (ip6q_locked) {
splx(s);
return (0);
}
ip6q_locked = 1;
splx(s);
return (1);
}
static __inline void
ip6q_unlock()
{
int s;
s = splvm();
ip6q_locked = 0;
splx(s);
}
#ifdef DIAGNOSTIC
#define IP6Q_LOCK() \
do { \
if (ip6q_lock_try() == 0) { \
printf("%s:%d: ip6q already locked\n", __FILE__, __LINE__); \
panic("ip6q_lock"); \
} \
} while (0)
#define IP6Q_LOCK_CHECK() \
do { \
if (ip6q_locked == 0) { \
printf("%s:%d: ip6q lock not held\n", __FILE__, __LINE__); \
panic("ip6q lock check"); \
} \
} while (0)
#else
#define IP6Q_LOCK() (void) ip6q_lock_try()
#define IP6Q_LOCK_CHECK() /* nothing */
#endif
#define IP6Q_UNLOCK() ip6q_unlock()
/*
* Initialise reassembly queue and fragment identifier.
*/
void
frag6_init(void)
{
TAILQ_INIT(&frag6_queue);
}
/*
* In RFC2460, fragment and reassembly rule do not agree with each other,
* in terms of next header field handling in fragment header.
* While the sender will use the same value for all of the fragmented packets,
* receiver is suggested not to check the consistency.
*
* fragment rule (p20):
* (2) A Fragment header containing:
* The Next Header value that identifies the first header of
* the Fragmentable Part of the original packet.
* -> next header field is same for all fragments
*
* reassembly rule (p21):
* The Next Header field of the last header of the Unfragmentable
* Part is obtained from the Next Header field of the first
* fragment's Fragment header.
* -> should grab it from the first fragment only
*
* The following note also contradicts with fragment rule - noone is going to
* send different fragment with different next header field.
*
* additional note (p22):
* The Next Header values in the Fragment headers of different
* fragments of the same original packet may differ. Only the value
* from the Offset zero fragment packet is used for reassembly.
* -> should grab it from the first fragment only
*
* There is no explicit reason given in the RFC. Historical reason maybe?
*/
/*
* Fragment input
*/
int
frag6_input(struct mbuf **mp, int *offp, int proto)
{
struct mbuf *m = *mp, *t;
struct ip6_hdr *ip6;
struct ip6_frag *ip6f;
struct ip6q *q6;
struct ip6asfrag *af6, *ip6af, *naf6, *paf6;
int offset = *offp, nxt, i, next;
int first_frag = 0;
int fragoff, frgpartlen; /* must be larger than u_int16_t */
struct ifnet *dstifp;
#ifdef IN6_IFSTAT_STRICT
struct route_in6 ro;
struct sockaddr_in6 *dst;
#endif
u_int8_t ecn, ecn0;
ip6 = mtod(m, struct ip6_hdr *);
IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
if (ip6f == NULL)
return IPPROTO_DONE;
dstifp = NULL;
#ifdef IN6_IFSTAT_STRICT
/* find the destination interface of the packet. */
bzero(&ro, sizeof(ro));
dst = (struct sockaddr_in6 *)&ro.ro_dst;
dst->sin6_family = AF_INET6;
dst->sin6_len = sizeof(struct sockaddr_in6);
dst->sin6_addr = ip6->ip6_dst;
rtalloc_mpath((struct route *)&ro, &ip6->ip6_src.s6_addr32[0]);
if (ro.ro_rt != NULL && ro.ro_rt->rt_ifa != NULL)
dstifp = ((struct in6_ifaddr *)ro.ro_rt->rt_ifa)->ia_ifp;
if (ro.ro_rt != NULL) {
RTFREE(ro.ro_rt);
ro.ro_rt = NULL;
}
#else
/* we are violating the spec, this is not the destination interface */
if ((m->m_flags & M_PKTHDR) != 0)
dstifp = m->m_pkthdr.rcvif;
#endif
/* jumbo payload can't contain a fragment header */
if (ip6->ip6_plen == 0) {
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, offset);
in6_ifstat_inc(dstifp, ifs6_reass_fail);
return IPPROTO_DONE;
}
/*
* check whether fragment packet's fragment length is
* multiple of 8 octets.
* sizeof(struct ip6_frag) == 8
* sizeof(struct ip6_hdr) = 40
*/
if ((ip6f->ip6f_offlg & IP6F_MORE_FRAG) &&
(((ntohs(ip6->ip6_plen) - offset) & 0x7) != 0)) {
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
offsetof(struct ip6_hdr, ip6_plen));
in6_ifstat_inc(dstifp, ifs6_reass_fail);
return IPPROTO_DONE;
}
ip6stat.ip6s_fragments++;
in6_ifstat_inc(dstifp, ifs6_reass_reqd);
/* offset now points to data portion */
offset += sizeof(struct ip6_frag);
/*
* draft-gont-6man-ipv6-atomic-fragments-00: A host that receives an
* IPv6 packet which includes a Fragment Header with the "Fragment
* Offset" equal to 0 and the "M" bit equal to 0 MUST process such
* packet in isolation from any other packets/fragments.
*/
fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
if (fragoff == 0 && !(ip6f->ip6f_offlg & IP6F_MORE_FRAG)) {
ip6stat.ip6s_reassembled++;
in6_ifstat_inc(dstifp, ifs6_reass_ok);
*offp = offset;
return ip6f->ip6f_nxt;
}
IP6Q_LOCK();
/*
* Enforce upper bound on number of fragments.
* If maxfrag is 0, never accept fragments.
* If maxfrag is -1, accept all fragments without limitation.
*/
if (ip6_maxfrags < 0)
;
else if (frag6_nfrags >= (u_int)ip6_maxfrags)
goto dropfrag;
TAILQ_FOREACH(q6, &frag6_queue, ip6q_queue)
if (ip6f->ip6f_ident == q6->ip6q_ident &&
IN6_ARE_ADDR_EQUAL(&ip6->ip6_src, &q6->ip6q_src) &&
IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &q6->ip6q_dst))
break;
if (q6 == TAILQ_END(&frag6_queue)) {
/*
* the first fragment to arrive, create a reassembly queue.
*/
first_frag = 1;
/*
* Enforce upper bound on number of fragmented packets
* for which we attempt reassembly;
* If maxfragpackets is 0, never accept fragments.
* If maxfragpackets is -1, accept all fragments without
* limitation.
*/
if (ip6_maxfragpackets < 0)
;
else if (frag6_nfragpackets >= (u_int)ip6_maxfragpackets)
goto dropfrag;
frag6_nfragpackets++;
q6 = malloc(sizeof(*q6), M_FTABLE, M_DONTWAIT | M_ZERO);
if (q6 == NULL)
goto dropfrag;
TAILQ_INSERT_HEAD(&frag6_queue, q6, ip6q_queue);
/* ip6q_nxt will be filled afterwards, from 1st fragment */
LIST_INIT(&q6->ip6q_asfrag);
q6->ip6q_ident = ip6f->ip6f_ident;
q6->ip6q_ttl = IPV6_FRAGTTL;
q6->ip6q_src = ip6->ip6_src;
q6->ip6q_dst = ip6->ip6_dst;
q6->ip6q_unfrglen = -1; /* The 1st fragment has not arrived. */
q6->ip6q_nfrag = 0;
}
/*
* If it's the 1st fragment, record the length of the
* unfragmentable part and the next header of the fragment header.
*/
if (fragoff == 0) {
q6->ip6q_unfrglen = offset - sizeof(struct ip6_hdr) -
sizeof(struct ip6_frag);
q6->ip6q_nxt = ip6f->ip6f_nxt;
}
/*
* Check that the reassembled packet would not exceed 65535 bytes
* in size.
* If it would exceed, discard the fragment and return an ICMP error.
*/
frgpartlen = sizeof(struct ip6_hdr) + ntohs(ip6->ip6_plen) - offset;
if (q6->ip6q_unfrglen >= 0) {
/* The 1st fragment has already arrived. */
if (q6->ip6q_unfrglen + fragoff + frgpartlen > IPV6_MAXPACKET) {
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
offset - sizeof(struct ip6_frag) +
offsetof(struct ip6_frag, ip6f_offlg));
IP6Q_UNLOCK();
return (IPPROTO_DONE);
}
} else if (fragoff + frgpartlen > IPV6_MAXPACKET) {
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER,
offset - sizeof(struct ip6_frag) +
offsetof(struct ip6_frag, ip6f_offlg));
IP6Q_UNLOCK();
return (IPPROTO_DONE);
}
/*
* If it's the first fragment, do the above check for each
* fragment already stored in the reassembly queue.
*/
if (fragoff == 0) {
LIST_FOREACH_SAFE(af6, &q6->ip6q_asfrag, ip6af_list, naf6) {
if (q6->ip6q_unfrglen + af6->ip6af_off +
af6->ip6af_frglen > IPV6_MAXPACKET) {
struct mbuf *merr = IP6_REASS_MBUF(af6);
struct ip6_hdr *ip6err;
int erroff = af6->ip6af_offset;
/* dequeue the fragment. */
LIST_REMOVE(af6, ip6af_list);
free(af6, M_FTABLE);
/* adjust pointer. */
ip6err = mtod(merr, struct ip6_hdr *);
/*
* Restore source and destination addresses
* in the erroneous IPv6 header.
*/
ip6err->ip6_src = q6->ip6q_src;
ip6err->ip6_dst = q6->ip6q_dst;
icmp6_error(merr, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff - sizeof(struct ip6_frag) +
offsetof(struct ip6_frag, ip6f_offlg));
}
}
}
ip6af = malloc(sizeof(*ip6af), M_FTABLE, M_DONTWAIT | M_ZERO);
if (ip6af == NULL)
goto dropfrag;
ip6af->ip6af_flow = ip6->ip6_flow;
ip6af->ip6af_mff = ip6f->ip6f_offlg & IP6F_MORE_FRAG;
ip6af->ip6af_off = fragoff;
ip6af->ip6af_frglen = frgpartlen;
ip6af->ip6af_offset = offset;
IP6_REASS_MBUF(ip6af) = m;
if (first_frag) {
paf6 = LIST_END(&q6->ip6q_asfrag);
goto insert;
}
/*
* Handle ECN by comparing this segment with the first one;
* if CE is set, do not lose CE.
* drop if CE and not-ECT are mixed for the same packet.
*/
af6 = LIST_FIRST(&q6->ip6q_asfrag);
ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
ecn0 = (ntohl(af6->ip6af_flow) >> 20) & IPTOS_ECN_MASK;
if (ecn == IPTOS_ECN_CE) {
if (ecn0 == IPTOS_ECN_NOTECT) {
free(ip6af, M_FTABLE);
goto dropfrag;
}
if (ecn0 != IPTOS_ECN_CE)
af6->ip6af_flow |= htonl(IPTOS_ECN_CE << 20);
}
if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) {
free(ip6af, M_FTABLE);
goto dropfrag;
}
/*
* Find a segment which begins after this one does.
*/
for (paf6 = LIST_END(&q6->ip6q_asfrag),
af6 = LIST_FIRST(&q6->ip6q_asfrag);
af6 != LIST_END(&q6->ip6q_asfrag);
paf6 = af6, af6 = LIST_NEXT(af6, ip6af_list))
if (af6->ip6af_off > ip6af->ip6af_off)
break;
/*
* RFC 5722, Errata 3089: When reassembling an IPv6 datagram, if one
* or more its constituent fragments is determined to be an overlapping
* fragment, the entire datagram (and any constituent fragments) MUST
* be silently discarded.
*/
if (paf6 != LIST_END(&q6->ip6q_asfrag)) {
i = (paf6->ip6af_off + paf6->ip6af_frglen) - ip6af->ip6af_off;
if (i > 0) {
#if 0 /* suppress the noisy log */
log(LOG_ERR, "%d bytes of a fragment from %s "
"overlaps the previous fragment\n",
i, ip6_sprintf(&q6->ip6q_src));
#endif
free(ip6af, M_FTABLE);
goto flushfrags;
}
}
if (af6 != LIST_END(&q6->ip6q_asfrag)) {
i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
if (i > 0) {
#if 0 /* suppress the noisy log */
log(LOG_ERR, "%d bytes of a fragment from %s "
"overlaps the succeeding fragment",
i, ip6_sprintf(&q6->ip6q_src));
#endif
free(ip6af, M_FTABLE);
goto flushfrags;
}
}
insert:
/*
* Stick new segment in its place;
* check for complete reassembly.
* Move to front of packet queue, as we are
* the most recently active fragmented packet.
*/
if (paf6 != LIST_END(&q6->ip6q_asfrag))
LIST_INSERT_AFTER(paf6, ip6af, ip6af_list);
else
LIST_INSERT_HEAD(&q6->ip6q_asfrag, ip6af, ip6af_list);
frag6_nfrags++;
q6->ip6q_nfrag++;
#if 0 /* xxx */
if (q6 != TAILQ_FIRST(&frag6_queue)) {
TAILQ_REMOVE(&frag6_queue, q6, ip6q_queue);
TAILQ_INSERT_HEAD(&frag6_queue, q6, ip6q_queue);
}
#endif
next = 0;
for (paf6 = LIST_END(&q6->ip6q_asfrag),
af6 = LIST_FIRST(&q6->ip6q_asfrag);
af6 != LIST_END(&q6->ip6q_asfrag);
paf6 = af6, af6 = LIST_NEXT(af6, ip6af_list)) {
if (af6->ip6af_off != next) {
IP6Q_UNLOCK();
return IPPROTO_DONE;
}
next += af6->ip6af_frglen;
}
if (paf6->ip6af_mff) {
IP6Q_UNLOCK();
return IPPROTO_DONE;
}
/*
* Reassembly is complete; concatenate fragments.
*/
ip6af = LIST_FIRST(&q6->ip6q_asfrag);
LIST_REMOVE(ip6af, ip6af_list);
t = m = IP6_REASS_MBUF(ip6af);
while ((af6 = LIST_FIRST(&q6->ip6q_asfrag)) !=
LIST_END(&q6->ip6q_asfrag)) {
LIST_REMOVE(af6, ip6af_list);
while (t->m_next)
t = t->m_next;
t->m_next = IP6_REASS_MBUF(af6);
m_adj(t->m_next, af6->ip6af_offset);
free(af6, M_FTABLE);
}
/* adjust offset to point where the original next header starts */
offset = ip6af->ip6af_offset - sizeof(struct ip6_frag);
free(ip6af, M_FTABLE);
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_plen = htons((u_short)next + offset - sizeof(struct ip6_hdr));
ip6->ip6_src = q6->ip6q_src;
ip6->ip6_dst = q6->ip6q_dst;
nxt = q6->ip6q_nxt;
/* Delete frag6 header */
if (frag6_deletefraghdr(m, offset) != 0) {
TAILQ_REMOVE(&frag6_queue, q6, ip6q_queue);
frag6_nfrags -= q6->ip6q_nfrag;
free(q6, M_FTABLE);
frag6_nfragpackets--;
goto dropfrag;
}
/*
* Store NXT to the original.
*/
{
u_int8_t *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
*prvnxtp = nxt;
}
TAILQ_REMOVE(&frag6_queue, q6, ip6q_queue);
frag6_nfrags -= q6->ip6q_nfrag;
free(q6, M_FTABLE);
frag6_nfragpackets--;
if (m->m_flags & M_PKTHDR) { /* Isn't it always true? */
int plen = 0;
for (t = m; t; t = t->m_next)
plen += t->m_len;
m->m_pkthdr.len = plen;
}
ip6stat.ip6s_reassembled++;
in6_ifstat_inc(dstifp, ifs6_reass_ok);
/*
* Tell launch routine the next header
*/
*mp = m;
*offp = offset;
IP6Q_UNLOCK();
return nxt;
flushfrags:
while ((af6 = LIST_FIRST(&q6->ip6q_asfrag)) !=
LIST_END(&q6->ip6q_asfrag)) {
LIST_REMOVE(af6, ip6af_list);
m_freem(IP6_REASS_MBUF(af6));
free(af6, M_FTABLE);
}
ip6stat.ip6s_fragdropped += q6->ip6q_nfrag;
TAILQ_REMOVE(&frag6_queue, q6, ip6q_queue);
frag6_nfrags -= q6->ip6q_nfrag;
free(q6, M_FTABLE);
frag6_nfragpackets--;
dropfrag:
in6_ifstat_inc(dstifp, ifs6_reass_fail);
ip6stat.ip6s_fragdropped++;
m_freem(m);
IP6Q_UNLOCK();
return IPPROTO_DONE;
}
/*
* Delete fragment header after the unfragmentable header portions.
*/
int
frag6_deletefraghdr(struct mbuf *m, int offset)
{
struct mbuf *t;
if (m->m_len >= offset + sizeof(struct ip6_frag)) {
ovbcopy(mtod(m, caddr_t), mtod(m, caddr_t) +
sizeof(struct ip6_frag), offset);
m->m_data += sizeof(struct ip6_frag);
m->m_len -= sizeof(struct ip6_frag);
} else {
/* this comes with no copy if the boundary is on cluster */
if ((t = m_split(m, offset, M_DONTWAIT)) == NULL)
return (ENOBUFS);
m_adj(t, sizeof(struct ip6_frag));
m_cat(m, t);
}
return (0);
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
void
frag6_freef(struct ip6q *q6)
{
struct ip6asfrag *af6;
IP6Q_LOCK_CHECK();
while ((af6 = LIST_FIRST(&q6->ip6q_asfrag)) !=
LIST_END(&q6->ip6q_asfrag)) {
struct mbuf *m = IP6_REASS_MBUF(af6);
LIST_REMOVE(af6, ip6af_list);
/*
* Return ICMP time exceeded error for the 1st fragment.
* Just free other fragments.
*/
if (af6->ip6af_off == 0) {
struct ip6_hdr *ip6;
/* adjust pointer */
ip6 = mtod(m, struct ip6_hdr *);
/* restore source and destination addresses */
ip6->ip6_src = q6->ip6q_src;
ip6->ip6_dst = q6->ip6q_dst;
icmp6_error(m, ICMP6_TIME_EXCEEDED,
ICMP6_TIME_EXCEED_REASSEMBLY, 0);
} else
m_freem(m);
free(af6, M_FTABLE);
}
TAILQ_REMOVE(&frag6_queue, q6, ip6q_queue);
frag6_nfrags -= q6->ip6q_nfrag;
free(q6, M_FTABLE);
frag6_nfragpackets--;
}
/*
* IPv6 reassembling timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
frag6_slowtimo(void)
{
struct ip6q *q6, *nq6;
int s = splsoftnet();
extern struct route_in6 ip6_forward_rt;
IP6Q_LOCK();
TAILQ_FOREACH_SAFE(q6, &frag6_queue, ip6q_queue, nq6)
if (--q6->ip6q_ttl == 0) {
ip6stat.ip6s_fragtimeout++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(q6);
}
/*
* If we are over the maximum number of fragments
* (due to the limit being lowered), drain off
* enough to get down to the new limit.
*/
while (frag6_nfragpackets > (u_int)ip6_maxfragpackets &&
!TAILQ_EMPTY(&frag6_queue)) {
ip6stat.ip6s_fragoverflow++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(TAILQ_LAST(&frag6_queue, ip6q_head));
}
IP6Q_UNLOCK();
/*
* Routing changes might produce a better route than we last used;
* make sure we notice eventually, even if forwarding only for one
* destination and the cache is never replaced.
*/
if (ip6_forward_rt.ro_rt) {
RTFREE(ip6_forward_rt.ro_rt);
ip6_forward_rt.ro_rt = 0;
}
splx(s);
}
/*
* Drain off all datagram fragments.
*/
void
frag6_drain(void)
{
struct ip6q *q6;
if (ip6q_lock_try() == 0)
return;
while ((q6 = TAILQ_FIRST(&frag6_queue)) != TAILQ_END(&frag6_queue)) {
ip6stat.ip6s_fragdropped++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(q6);
}
IP6Q_UNLOCK();
}
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