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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/netinet6/frag6.c |
/*-
* 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.
*
* $KAME: frag6.c,v 1.33 2002/01/07 11:34:48 kjc Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/netinet6/frag6.c 238479 2012-07-15 11:27:15Z bz $");
#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 <net/vnet.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 <security/mac/mac_framework.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
static void frag6_enq(struct ip6asfrag *, struct ip6asfrag *);
static void frag6_deq(struct ip6asfrag *);
static void frag6_insque(struct ip6q *, struct ip6q *);
static void frag6_remque(struct ip6q *);
static void frag6_freef(struct ip6q *);
static struct mtx ip6qlock;
/*
* These fields all protected by ip6qlock.
*/
static VNET_DEFINE(u_int, frag6_nfragpackets);
static VNET_DEFINE(u_int, frag6_nfrags);
static VNET_DEFINE(struct ip6q, ip6q); /* ip6 reassemble queue */
#define V_frag6_nfragpackets VNET(frag6_nfragpackets)
#define V_frag6_nfrags VNET(frag6_nfrags)
#define V_ip6q VNET(ip6q)
#define IP6Q_LOCK_INIT() mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF);
#define IP6Q_LOCK() mtx_lock(&ip6qlock)
#define IP6Q_TRYLOCK() mtx_trylock(&ip6qlock)
#define IP6Q_LOCK_ASSERT() mtx_assert(&ip6qlock, MA_OWNED)
#define IP6Q_UNLOCK() mtx_unlock(&ip6qlock)
static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header");
/*
* Initialise reassembly queue and fragment identifier.
*/
static void
frag6_change(void *tag)
{
V_ip6_maxfragpackets = nmbclusters / 4;
V_ip6_maxfrags = nmbclusters / 4;
}
void
frag6_init(void)
{
V_ip6_maxfragpackets = nmbclusters / 4;
V_ip6_maxfrags = nmbclusters / 4;
V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q;
if (!IS_DEFAULT_VNET(curvnet))
return;
EVENTHANDLER_REGISTER(nmbclusters_change,
frag6_change, NULL, EVENTHANDLER_PRI_ANY);
IP6Q_LOCK_INIT();
}
/*
* 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, *af6dwn;
#ifdef IN6_IFSTAT_STRICT
struct in6_ifaddr *ia;
#endif
int offset = *offp, nxt, i, next;
int first_frag = 0;
int fragoff, frgpartlen; /* must be larger than u_int16_t */
struct ifnet *dstifp;
u_int8_t ecn, ecn0;
#if 0
char ip6buf[INET6_ADDRSTRLEN];
#endif
ip6 = mtod(m, struct ip6_hdr *);
#ifndef PULLDOWN_TEST
IP6_EXTHDR_CHECK(m, offset, sizeof(struct ip6_frag), IPPROTO_DONE);
ip6f = (struct ip6_frag *)((caddr_t)ip6 + offset);
#else
IP6_EXTHDR_GET(ip6f, struct ip6_frag *, m, offset, sizeof(*ip6f));
if (ip6f == NULL)
return (IPPROTO_DONE);
#endif
dstifp = NULL;
#ifdef IN6_IFSTAT_STRICT
/* find the destination interface of the packet. */
if ((ia = ip6_getdstifaddr(m)) != NULL) {
dstifp = ia->ia_ifp;
ifa_free(&ia->ia_ifa);
}
#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;
}
V_ip6stat.ip6s_fragments++;
in6_ifstat_inc(dstifp, ifs6_reass_reqd);
/* offset now points to data portion */
offset += sizeof(struct ip6_frag);
/*
* XXX-BZ RFC XXXX (draft-gont-6man-ipv6-atomic-fragments)
* Handle "atomic" fragments (offset and m bit set to 0) upfront,
* unrelated to any reassembly. Just skip the fragment header.
*/
if ((ip6f->ip6f_offlg & ~IP6F_RESERVED_MASK) == 0) {
/* XXX-BZ we want dedicated counters for this. */
V_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 (V_ip6_maxfrags < 0)
;
else if (V_frag6_nfrags >= (u_int)V_ip6_maxfrags)
goto dropfrag;
for (q6 = V_ip6q.ip6q_next; q6 != &V_ip6q; q6 = q6->ip6q_next)
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)
#ifdef MAC
&& mac_ip6q_match(m, q6)
#endif
)
break;
if (q6 == &V_ip6q) {
/*
* 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 (V_ip6_maxfragpackets < 0)
;
else if (V_frag6_nfragpackets >= (u_int)V_ip6_maxfragpackets)
goto dropfrag;
V_frag6_nfragpackets++;
q6 = (struct ip6q *)malloc(sizeof(struct ip6q), M_FTABLE,
M_NOWAIT);
if (q6 == NULL)
goto dropfrag;
bzero(q6, sizeof(*q6));
#ifdef MAC
if (mac_ip6q_init(q6, M_NOWAIT) != 0) {
free(q6, M_FTABLE);
goto dropfrag;
}
mac_ip6q_create(m, q6);
#endif
frag6_insque(q6, &V_ip6q);
/* ip6q_nxt will be filled afterwards, from 1st fragment */
q6->ip6q_down = q6->ip6q_up = (struct ip6asfrag *)q6;
#ifdef notyet
q6->ip6q_nxtp = (u_char *)nxtp;
#endif
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_ecn =
(ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
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.
*/
fragoff = ntohs(ip6f->ip6f_offlg & IP6F_OFF_MASK);
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) {
for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
af6 = af6dwn) {
af6dwn = af6->ip6af_down;
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. */
frag6_deq(af6);
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 = (struct ip6asfrag *)malloc(sizeof(struct ip6asfrag), M_FTABLE,
M_NOWAIT);
if (ip6af == NULL)
goto dropfrag;
bzero(ip6af, sizeof(*ip6af));
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) {
af6 = (struct ip6asfrag *)q6;
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.
*/
ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
ecn0 = q6->ip6q_ecn;
if (ecn == IPTOS_ECN_CE) {
if (ecn0 == IPTOS_ECN_NOTECT) {
free(ip6af, M_FTABLE);
goto dropfrag;
}
if (ecn0 != IPTOS_ECN_CE)
q6->ip6q_ecn = IPTOS_ECN_CE;
}
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 (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
af6 = af6->ip6af_down)
if (af6->ip6af_off > ip6af->ip6af_off)
break;
#if 0
/*
* If there is a preceding segment, it may provide some of
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us.
*/
if (af6->ip6af_up != (struct ip6asfrag *)q6) {
i = af6->ip6af_up->ip6af_off + af6->ip6af_up->ip6af_frglen
- ip6af->ip6af_off;
if (i > 0) {
if (i >= ip6af->ip6af_frglen)
goto dropfrag;
m_adj(IP6_REASS_MBUF(ip6af), i);
ip6af->ip6af_off += i;
ip6af->ip6af_frglen -= i;
}
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
while (af6 != (struct ip6asfrag *)q6 &&
ip6af->ip6af_off + ip6af->ip6af_frglen > af6->ip6af_off) {
i = (ip6af->ip6af_off + ip6af->ip6af_frglen) - af6->ip6af_off;
if (i < af6->ip6af_frglen) {
af6->ip6af_frglen -= i;
af6->ip6af_off += i;
m_adj(IP6_REASS_MBUF(af6), i);
break;
}
af6 = af6->ip6af_down;
m_freem(IP6_REASS_MBUF(af6->ip6af_up));
frag6_deq(af6->ip6af_up);
}
#else
/*
* If the incoming framgent overlaps some existing fragments in
* the reassembly queue, drop it, since it is dangerous to override
* existing fragments from a security point of view.
* We don't know which fragment is the bad guy - here we trust
* fragment that came in earlier, with no real reason.
*
* Note: due to changes after disabling this part, mbuf passed to
* m_adj() below now does not meet the requirement.
*/
if (af6->ip6af_up != (struct ip6asfrag *)q6) {
i = af6->ip6af_up->ip6af_off + af6->ip6af_up->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(ip6buf, &q6->ip6q_src));
#endif
free(ip6af, M_FTABLE);
goto dropfrag;
}
}
if (af6 != (struct ip6asfrag *)q6) {
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(ip6buf, &q6->ip6q_src));
#endif
free(ip6af, M_FTABLE);
goto dropfrag;
}
}
#endif
insert:
#ifdef MAC
if (!first_frag)
mac_ip6q_update(m, q6);
#endif
/*
* 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.
*/
frag6_enq(ip6af, af6->ip6af_up);
V_frag6_nfrags++;
q6->ip6q_nfrag++;
#if 0 /* xxx */
if (q6 != V_ip6q.ip6q_next) {
frag6_remque(q6);
frag6_insque(q6, &V_ip6q);
}
#endif
next = 0;
for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
af6 = af6->ip6af_down) {
if (af6->ip6af_off != next) {
IP6Q_UNLOCK();
return IPPROTO_DONE;
}
next += af6->ip6af_frglen;
}
if (af6->ip6af_up->ip6af_mff) {
IP6Q_UNLOCK();
return IPPROTO_DONE;
}
/*
* Reassembly is complete; concatenate fragments.
*/
ip6af = q6->ip6q_down;
t = m = IP6_REASS_MBUF(ip6af);
af6 = ip6af->ip6af_down;
frag6_deq(ip6af);
while (af6 != (struct ip6asfrag *)q6) {
af6dwn = af6->ip6af_down;
frag6_deq(af6);
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);
af6 = af6dwn;
}
/* 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));
if (q6->ip6q_ecn == IPTOS_ECN_CE)
ip6->ip6_flow |= htonl(IPTOS_ECN_CE << 20);
nxt = q6->ip6q_nxt;
#ifdef notyet
*q6->ip6q_nxtp = (u_char)(nxt & 0xff);
#endif
/* Delete frag6 header */
if (m->m_len >= offset + sizeof(struct ip6_frag)) {
/* This is the only possible case with !PULLDOWN_TEST */
ovbcopy((caddr_t)ip6, (caddr_t)ip6 + 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) {
frag6_remque(q6);
V_frag6_nfrags -= q6->ip6q_nfrag;
#ifdef MAC
mac_ip6q_destroy(q6);
#endif
free(q6, M_FTABLE);
V_frag6_nfragpackets--;
goto dropfrag;
}
m_adj(t, sizeof(struct ip6_frag));
m_cat(m, t);
}
/*
* Store NXT to the original.
*/
{
char *prvnxtp = ip6_get_prevhdr(m, offset); /* XXX */
*prvnxtp = nxt;
}
frag6_remque(q6);
V_frag6_nfrags -= q6->ip6q_nfrag;
#ifdef MAC
mac_ip6q_reassemble(q6, m);
mac_ip6q_destroy(q6);
#endif
free(q6, M_FTABLE);
V_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;
}
V_ip6stat.ip6s_reassembled++;
in6_ifstat_inc(dstifp, ifs6_reass_ok);
/*
* Tell launch routine the next header
*/
*mp = m;
*offp = offset;
IP6Q_UNLOCK();
return nxt;
dropfrag:
IP6Q_UNLOCK();
in6_ifstat_inc(dstifp, ifs6_reass_fail);
V_ip6stat.ip6s_fragdropped++;
m_freem(m);
return IPPROTO_DONE;
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
void
frag6_freef(struct ip6q *q6)
{
struct ip6asfrag *af6, *down6;
IP6Q_LOCK_ASSERT();
for (af6 = q6->ip6q_down; af6 != (struct ip6asfrag *)q6;
af6 = down6) {
struct mbuf *m = IP6_REASS_MBUF(af6);
down6 = af6->ip6af_down;
frag6_deq(af6);
/*
* 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);
}
frag6_remque(q6);
V_frag6_nfrags -= q6->ip6q_nfrag;
#ifdef MAC
mac_ip6q_destroy(q6);
#endif
free(q6, M_FTABLE);
V_frag6_nfragpackets--;
}
/*
* Put an ip fragment on a reassembly chain.
* Like insque, but pointers in middle of structure.
*/
void
frag6_enq(struct ip6asfrag *af6, struct ip6asfrag *up6)
{
IP6Q_LOCK_ASSERT();
af6->ip6af_up = up6;
af6->ip6af_down = up6->ip6af_down;
up6->ip6af_down->ip6af_up = af6;
up6->ip6af_down = af6;
}
/*
* To frag6_enq as remque is to insque.
*/
void
frag6_deq(struct ip6asfrag *af6)
{
IP6Q_LOCK_ASSERT();
af6->ip6af_up->ip6af_down = af6->ip6af_down;
af6->ip6af_down->ip6af_up = af6->ip6af_up;
}
void
frag6_insque(struct ip6q *new, struct ip6q *old)
{
IP6Q_LOCK_ASSERT();
new->ip6q_prev = old;
new->ip6q_next = old->ip6q_next;
old->ip6q_next->ip6q_prev= new;
old->ip6q_next = new;
}
void
frag6_remque(struct ip6q *p6)
{
IP6Q_LOCK_ASSERT();
p6->ip6q_prev->ip6q_next = p6->ip6q_next;
p6->ip6q_next->ip6q_prev = p6->ip6q_prev;
}
/*
* IPv6 reassembling timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
frag6_slowtimo(void)
{
VNET_ITERATOR_DECL(vnet_iter);
struct ip6q *q6;
VNET_LIST_RLOCK_NOSLEEP();
IP6Q_LOCK();
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
q6 = V_ip6q.ip6q_next;
if (q6)
while (q6 != &V_ip6q) {
--q6->ip6q_ttl;
q6 = q6->ip6q_next;
if (q6->ip6q_prev->ip6q_ttl == 0) {
V_ip6stat.ip6s_fragtimeout++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(q6->ip6q_prev);
}
}
/*
* 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 (V_frag6_nfragpackets > (u_int)V_ip6_maxfragpackets &&
V_ip6q.ip6q_prev) {
V_ip6stat.ip6s_fragoverflow++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(V_ip6q.ip6q_prev);
}
CURVNET_RESTORE();
}
IP6Q_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
}
/*
* Drain off all datagram fragments.
*/
void
frag6_drain(void)
{
VNET_ITERATOR_DECL(vnet_iter);
VNET_LIST_RLOCK_NOSLEEP();
if (IP6Q_TRYLOCK() == 0) {
VNET_LIST_RUNLOCK_NOSLEEP();
return;
}
VNET_FOREACH(vnet_iter) {
CURVNET_SET(vnet_iter);
while (V_ip6q.ip6q_next != &V_ip6q) {
V_ip6stat.ip6s_fragdropped++;
/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */
frag6_freef(V_ip6q.ip6q_next);
}
CURVNET_RESTORE();
}
IP6Q_UNLOCK();
VNET_LIST_RUNLOCK_NOSLEEP();
}