ref: dfec09c436a8a328fc97007cf2dc3cd5476cc748
dir: /sys/src/9/ip/icmp6.c/
/*
* Internet Control Message Protocol for IPv6
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "ip.h"
#include "ipv6.h"
enum
{
InMsgs6,
InErrors6,
OutMsgs6,
CsumErrs6,
LenErrs6,
HlenErrs6,
HoplimErrs6,
IcmpCodeErrs6,
TargetErrs6,
OptlenErrs6,
AddrmxpErrs6,
RouterAddrErrs6,
Nstats6,
};
enum {
ICMP_USEAD6 = 40,
};
enum {
Oflag = 1<<5,
Sflag = 1<<6,
Rflag = 1<<7,
};
enum {
/* ICMPv6 types */
EchoReply = 0,
UnreachableV6 = 1,
PacketTooBigV6 = 2,
TimeExceedV6 = 3,
SrcQuench = 4,
ParamProblemV6 = 4,
Redirect = 5,
EchoRequest = 8,
TimeExceed = 11,
InParmProblem = 12,
Timestamp = 13,
TimestampReply = 14,
InfoRequest = 15,
InfoReply = 16,
AddrMaskRequest = 17,
AddrMaskReply = 18,
EchoRequestV6 = 128,
EchoReplyV6 = 129,
RouterSolicit = 133,
RouterAdvert = 134,
NbrSolicit = 135,
NbrAdvert = 136,
RedirectV6 = 137,
Maxtype6 = 137,
};
/* on-the-wire packet formats */
typedef struct IPICMP IPICMP;
typedef struct Ndpkt Ndpkt;
typedef struct NdiscC NdiscC;
/* we do this to avoid possible struct padding */
#define ICMPHDR \
IPV6HDR; \
uchar type; \
uchar code; \
uchar cksum[2]; \
uchar icmpid[2]; \
uchar seq[2]
struct IPICMP {
ICMPHDR;
uchar payload[];
};
#define IPICMPSZ offsetof(IPICMP, payload[0])
struct NdiscC {
ICMPHDR;
uchar target[IPaddrlen];
uchar payload[];
};
#define NDISCSZ offsetof(NdiscC, payload[0])
struct Ndpkt {
ICMPHDR;
uchar target[IPaddrlen];
uchar otype;
uchar olen; /* length in units of 8 octets(incl type, code),
* 1 for IEEE 802 addresses */
uchar lnaddr[6]; /* link-layer address */
uchar payload[];
};
#define NDPKTSZ offsetof(Ndpkt, payload[0])
typedef struct Icmppriv6
{
ulong stats[Nstats6];
/* message counts */
ulong in[Maxtype6+1];
ulong out[Maxtype6+1];
} Icmppriv6;
typedef struct Icmpcb6
{
QLock;
uchar headers;
} Icmpcb6;
char *icmpnames6[Maxtype6+1] =
{
[EchoReply] "EchoReply",
[UnreachableV6] "UnreachableV6",
[PacketTooBigV6] "PacketTooBigV6",
[TimeExceedV6] "TimeExceedV6",
[SrcQuench] "SrcQuench",
[Redirect] "Redirect",
[EchoRequest] "EchoRequest",
[TimeExceed] "TimeExceed",
[InParmProblem] "InParmProblem",
[Timestamp] "Timestamp",
[TimestampReply] "TimestampReply",
[InfoRequest] "InfoRequest",
[InfoReply] "InfoReply",
[AddrMaskRequest] "AddrMaskRequest",
[AddrMaskReply] "AddrMaskReply",
[EchoRequestV6] "EchoRequestV6",
[EchoReplyV6] "EchoReplyV6",
[RouterSolicit] "RouterSolicit",
[RouterAdvert] "RouterAdvert",
[NbrSolicit] "NbrSolicit",
[NbrAdvert] "NbrAdvert",
[RedirectV6] "RedirectV6",
};
static char *statnames6[Nstats6] =
{
[InMsgs6] "InMsgs",
[InErrors6] "InErrors",
[OutMsgs6] "OutMsgs",
[CsumErrs6] "CsumErrs",
[LenErrs6] "LenErrs",
[HlenErrs6] "HlenErrs",
[HoplimErrs6] "HoplimErrs",
[IcmpCodeErrs6] "IcmpCodeErrs",
[TargetErrs6] "TargetErrs",
[OptlenErrs6] "OptlenErrs",
[AddrmxpErrs6] "AddrmxpErrs",
[RouterAddrErrs6] "RouterAddrErrs",
};
static char *unreachcode[] =
{
[Icmp6_no_route] "no route to destination",
[Icmp6_ad_prohib] "comm with destination administratively prohibited",
[Icmp6_out_src_scope] "beyond scope of source address",
[Icmp6_adr_unreach] "address unreachable",
[Icmp6_port_unreach] "port unreachable",
[Icmp6_gress_src_fail] "source address failed ingress/egress policy",
[Icmp6_rej_route] "reject route to destination",
[Icmp6_unknown] "icmp unreachable: unknown code",
};
static void icmpkick6(void *x, Block *bp);
static void
icmpcreate6(Conv *c)
{
c->rq = qopen(64*1024, Qmsg, 0, c);
c->wq = qbypass(icmpkick6, c);
}
static void
set_cksum(Block *bp)
{
IPICMP *p = (IPICMP *)(bp->rp);
hnputl(p->vcf, 0); /* borrow IP header as pseudoheader */
hnputs(p->ploadlen, blocklen(bp) - IP6HDR);
p->proto = 0;
p->ttl = ICMPv6; /* ttl gets set later */
hnputs(p->cksum, 0);
hnputs(p->cksum, ptclcsum(bp, 0, blocklen(bp)));
p->proto = ICMPv6;
}
static Block *
newIPICMP(int packetlen)
{
Block *nbp;
nbp = allocb(packetlen);
nbp->wp += packetlen;
memset(nbp->rp, 0, packetlen);
return nbp;
}
static void
icmpadvise6(Proto *icmp, Block *bp, char *msg)
{
ushort recid;
Conv **c, *s;
IPICMP *p;
p = (IPICMP *)bp->rp;
recid = nhgets(p->icmpid);
for(c = icmp->conv; (s = *c) != nil; c++){
if(s->lport == recid)
if(ipcmp(s->laddr, p->src) == 0)
if(ipcmp(s->raddr, p->dst) == 0){
if(s->ignoreadvice)
break;
qhangup(s->rq, msg);
qhangup(s->wq, msg);
break;
}
}
freeblist(bp);
}
static void
icmpkick6(void *x, Block *bp)
{
uchar laddr[IPaddrlen], raddr[IPaddrlen];
Conv *c = x;
IPICMP *p;
Icmppriv6 *ipriv = c->p->priv;
Icmpcb6 *icb = (Icmpcb6*)c->ptcl;
if(bp == nil)
return;
if(icb->headers==6) {
/* get user specified addresses */
bp = pullupblock(bp, ICMP_USEAD6);
if(bp == nil)
return;
bp->rp += 8;
ipmove(laddr, bp->rp);
bp->rp += IPaddrlen;
ipmove(raddr, bp->rp);
bp->rp += IPaddrlen;
bp = padblock(bp, IP6HDR);
}
if(blocklen(bp) < IPICMPSZ){
freeblist(bp);
return;
}
p = (IPICMP *)(bp->rp);
if(icb->headers == 6) {
ipmove(p->dst, raddr);
ipmove(p->src, laddr);
} else {
ipmove(p->dst, c->raddr);
ipmove(p->src, c->laddr);
hnputs(p->icmpid, c->lport);
}
set_cksum(bp);
p->vcf[0] = 0x06 << 4;
if(p->type <= Maxtype6)
ipriv->out[p->type]++;
ipoput6(c->p->f, bp, 0, c->ttl, c->tos, nil);
}
static char*
icmpctl6(Conv *c, char **argv, int argc)
{
Icmpcb6 *icb;
icb = (Icmpcb6*) c->ptcl;
if(argc==1 && strcmp(argv[0], "headers")==0) {
icb->headers = 6;
return nil;
}
return "unknown control request";
}
static void
goticmpkt6(Proto *icmp, Block *bp, int muxkey)
{
ushort recid;
uchar *addr;
Conv **c, *s;
IPICMP *p = (IPICMP *)bp->rp;
if(muxkey == 0) {
recid = nhgets(p->icmpid);
addr = p->src;
} else {
recid = muxkey;
addr = p->dst;
}
for(c = icmp->conv; (s = *c) != nil; c++){
if(s->lport == recid)
if(ipcmp(s->laddr, p->dst) == 0 || ipcmp(s->raddr, addr) == 0)
qpass(s->rq, copyblock(bp, blocklen(bp)));
}
freeblist(bp);
}
static Block *
mkechoreply6(Block *bp, Ipifc *ifc)
{
uchar addr[IPaddrlen];
IPICMP *p = (IPICMP *)(bp->rp);
if(isv6mcast(p->src))
return nil;
ipmove(addr, p->src);
if(!isv6mcast(p->dst))
ipmove(p->src, p->dst);
else if (!ipv6local(ifc, p->src, addr))
return nil;
ipmove(p->dst, addr);
p->type = EchoReplyV6;
set_cksum(bp);
return bp;
}
/*
* sends out an ICMPv6 neighbor solicitation
* suni == SRC_UNSPEC or SRC_UNI,
* tuni == TARG_MULTI => multicast for address resolution,
* and tuni == TARG_UNI => neighbor reachability.
*/
void
icmpns(Fs *f, uchar* src, int suni, uchar* targ, int tuni, uchar* mac)
{
Block *nbp;
Ndpkt *np;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
nbp = newIPICMP(NDPKTSZ);
np = (Ndpkt*) nbp->rp;
if(suni == SRC_UNSPEC)
ipmove(np->src, v6Unspecified);
else
ipmove(np->src, src);
if(tuni == TARG_UNI)
ipmove(np->dst, targ);
else
ipv62smcast(np->dst, targ);
np->type = NbrSolicit;
np->code = 0;
ipmove(np->target, targ);
if(suni != SRC_UNSPEC) {
np->otype = SRC_LLADDR;
np->olen = 1; /* 1+1+6 = 8 = 1 8-octet */
memmove(np->lnaddr, mac, sizeof(np->lnaddr));
} else
nbp->wp -= NDPKTSZ - NDISCSZ;
set_cksum(nbp);
np = (Ndpkt*)nbp->rp;
np->ttl = HOP_LIMIT;
np->vcf[0] = 0x06 << 4;
ipriv->out[NbrSolicit]++;
netlog(f, Logicmp, "sending neighbor solicitation %I\n", targ);
ipoput6(f, nbp, 0, MAXTTL, DFLTTOS, nil);
}
/*
* sends out an ICMPv6 neighbor advertisement. pktflags == RSO flags.
*/
void
icmpna(Fs *f, uchar* src, uchar* dst, uchar* targ, uchar* mac, uchar flags)
{
Block *nbp;
Ndpkt *np;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
nbp = newIPICMP(NDPKTSZ);
np = (Ndpkt*)nbp->rp;
ipmove(np->src, src);
ipmove(np->dst, dst);
np->type = NbrAdvert;
np->code = 0;
np->icmpid[0] = flags;
ipmove(np->target, targ);
np->otype = TARGET_LLADDR;
np->olen = 1;
memmove(np->lnaddr, mac, sizeof(np->lnaddr));
set_cksum(nbp);
np = (Ndpkt*)nbp->rp;
np->ttl = HOP_LIMIT;
np->vcf[0] = 0x06 << 4;
ipriv->out[NbrAdvert]++;
netlog(f, Logicmp, "sending neighbor advertisement %I\n", targ);
ipoput6(f, nbp, 0, MAXTTL, DFLTTOS, nil);
}
void
icmphostunr6(Fs *f, Ipifc *ifc, Block *bp, int code, int tome)
{
int osz = BLEN(bp);
int sz = MIN(IPICMPSZ + osz, v6MINTU);
Block *nbp;
IPICMP *np;
Ip6hdr *p;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
uchar ia[IPaddrlen];
p = (Ip6hdr *)bp->rp;
if(isv6mcast(p->dst) || isv6mcast(p->src) || !ipv6local(ifc, ia, p->src))
return;
netlog(f, Logicmp, "send icmphostunr %I -> src %I dst %I\n",
ia, p->src, p->dst);
nbp = newIPICMP(sz);
np = (IPICMP *)nbp->rp;
ipmove(np->src, ia);
ipmove(np->dst, p->src);
np->type = UnreachableV6;
np->code = code;
memmove(nbp->rp + IPICMPSZ, bp->rp, sz - IPICMPSZ);
set_cksum(nbp);
np->ttl = HOP_LIMIT;
np->vcf[0] = 0x06 << 4;
ipriv->out[UnreachableV6]++;
if(tome)
ipiput6(f, ifc, nbp);
else
ipoput6(f, nbp, 0, MAXTTL, DFLTTOS, nil);
}
void
icmpttlexceeded6(Fs *f, Ipifc *ifc, Block *bp)
{
int osz = BLEN(bp);
int sz = MIN(IPICMPSZ + osz, v6MINTU);
Block *nbp;
IPICMP *np;
Ip6hdr *p;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
uchar ia[IPaddrlen];
p = (Ip6hdr *)bp->rp;
if(isv6mcast(p->dst) || isv6mcast(p->src) || !ipv6local(ifc, ia, p->src))
return;
netlog(f, Logicmp, "send icmpttlexceeded6 %I -> src %I dst %I\n",
ia, p->src, p->dst);
nbp = newIPICMP(sz);
np = (IPICMP *) nbp->rp;
ipmove(np->src, ia);
ipmove(np->dst, p->src);
np->type = TimeExceedV6;
np->code = 0;
memmove(nbp->rp + IPICMPSZ, bp->rp, sz - IPICMPSZ);
set_cksum(nbp);
np->ttl = HOP_LIMIT;
np->vcf[0] = 0x06 << 4;
ipriv->out[TimeExceedV6]++;
ipoput6(f, nbp, 0, MAXTTL, DFLTTOS, nil);
}
void
icmppkttoobig6(Fs *f, Ipifc *ifc, Block *bp)
{
int osz = BLEN(bp);
int sz = MIN(IPICMPSZ + osz, v6MINTU);
Block *nbp;
IPICMP *np;
Ip6hdr *p;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
uchar ia[IPaddrlen];
p = (Ip6hdr *)bp->rp;
if(isv6mcast(p->dst) || isv6mcast(p->src) || !ipv6local(ifc, ia, p->src))
return;
netlog(f, Logicmp, "send icmppkttoobig6 %I -> src %I dst %I\n",
ia, p->src, p->dst);
nbp = newIPICMP(sz);
np = (IPICMP *)nbp->rp;
ipmove(np->src, ia);
ipmove(np->dst, p->src);
np->type = PacketTooBigV6;
np->code = 0;
hnputl(np->icmpid, ifc->maxtu - ifc->m->hsize);
memmove(nbp->rp + IPICMPSZ, bp->rp, sz - IPICMPSZ);
set_cksum(nbp);
np->ttl = HOP_LIMIT;
np->vcf[0] = 0x06 << 4;
ipriv->out[PacketTooBigV6]++;
ipoput6(f, nbp, 0, MAXTTL, DFLTTOS, nil);
}
/*
* RFC 2461, pages 39-40, pages 57-58.
*/
static int
valid(Proto *icmp, Ipifc *ifc, Block *bp, Icmppriv6 *ipriv)
{
int sz, osz, unsp, n, ttl, iplen;
int pktsz = BLEN(bp);
uchar *packet = bp->rp;
IPICMP *p = (IPICMP *) packet;
Ndpkt *np;
USED(ifc);
n = blocklen(bp);
if(n < IPICMPSZ) {
ipriv->stats[HlenErrs6]++;
netlog(icmp->f, Logicmp, "icmp hlen %d\n", n);
goto err;
}
iplen = nhgets(p->ploadlen);
if(iplen > n - IP6HDR) {
ipriv->stats[LenErrs6]++;
netlog(icmp->f, Logicmp, "icmp length %d\n", iplen);
goto err;
}
/* Rather than construct explicit pseudoheader, overwrite IPv6 header */
if(p->proto != ICMPv6) {
/* This code assumes no extension headers!!! */
netlog(icmp->f, Logicmp, "icmp error: extension header\n");
goto err;
}
memset(packet, 0, 4);
ttl = p->ttl;
p->ttl = p->proto;
p->proto = 0;
if(ptclcsum(bp, 0, iplen + IP6HDR)) {
ipriv->stats[CsumErrs6]++;
netlog(icmp->f, Logicmp, "icmp checksum error\n");
goto err;
}
p->proto = p->ttl;
p->ttl = ttl;
/* additional tests for some pkt types */
if (p->type == NbrSolicit || p->type == NbrAdvert ||
p->type == RouterAdvert || p->type == RouterSolicit ||
p->type == RedirectV6) {
if(p->ttl != HOP_LIMIT) {
ipriv->stats[HoplimErrs6]++;
goto err;
}
if(p->code != 0) {
ipriv->stats[IcmpCodeErrs6]++;
goto err;
}
switch (p->type) {
case NbrSolicit:
case NbrAdvert:
np = (Ndpkt*) p;
if(isv6mcast(np->target)) {
ipriv->stats[TargetErrs6]++;
goto err;
}
if(optexsts(np) && np->olen == 0) {
ipriv->stats[OptlenErrs6]++;
goto err;
}
if (p->type == NbrSolicit &&
ipcmp(np->src, v6Unspecified) == 0)
if(!issmcast(np->dst) || optexsts(np)) {
ipriv->stats[AddrmxpErrs6]++;
goto err;
}
if(p->type == NbrAdvert)
if(isv6mcast(np->dst) &&
(nhgets(np->icmpid) & Sflag)){
ipriv->stats[AddrmxpErrs6]++;
goto err;
}
break;
case RouterAdvert:
if(pktsz - IP6HDR < 16) {
ipriv->stats[HlenErrs6]++;
goto err;
}
if(!islinklocal(p->src)) {
ipriv->stats[RouterAddrErrs6]++;
goto err;
}
sz = IPICMPSZ + 8;
while (sz+8 <= pktsz) {
osz = packet[sz+1];
if(osz <= 0) {
ipriv->stats[OptlenErrs6]++;
goto err;
}
sz += 8*osz;
}
break;
case RouterSolicit:
if(pktsz - IP6HDR < 8) {
ipriv->stats[HlenErrs6]++;
goto err;
}
unsp = (ipcmp(p->src, v6Unspecified) == 0);
sz = IPICMPSZ + 8;
while (sz+8 <= pktsz) {
osz = packet[sz+1];
if(osz <= 0 ||
(unsp && packet[sz] == SRC_LLADDR)) {
ipriv->stats[OptlenErrs6]++;
goto err;
}
sz += 8*osz;
}
break;
case RedirectV6:
/* to be filled in */
break;
default:
goto err;
}
}
return 1;
err:
ipriv->stats[InErrors6]++;
return 0;
}
static int
targettype(Fs *f, Ipifc *ifc, uchar *target)
{
Iplifc *lifc;
int t;
if((lifc = iplocalonifc(ifc, target)) != nil)
t = lifc->tentative? Tunitent: Tunirany;
else if(ipproxyifc(f, ifc, target))
t = Tuniproxy;
else
t = 0;
return t;
}
static void
icmpiput6(Proto *icmp, Ipifc *ifc, Block *bp)
{
char *msg, m2[128];
uchar pktflags;
uchar *packet = bp->rp;
uchar ia[IPaddrlen];
Block *r;
IPICMP *p = (IPICMP *)packet;
Icmppriv6 *ipriv = icmp->priv;
Iplifc *lifc;
Ndpkt* np;
Proto *pr;
if(!valid(icmp, ifc, bp, ipriv) || p->type > Maxtype6)
goto raise;
ipriv->in[p->type]++;
switch(p->type) {
case EchoRequestV6:
if(bp->next != nil)
bp = concatblock(bp);
r = mkechoreply6(bp, ifc);
if(r == nil)
goto raise;
ipriv->out[EchoReply]++;
ipoput6(icmp->f, r, 0, MAXTTL, DFLTTOS, nil);
break;
case UnreachableV6:
if(p->code >= nelem(unreachcode))
msg = unreachcode[Icmp6_unknown];
else
msg = unreachcode[p->code];
bp->rp += IPICMPSZ;
if(blocklen(bp) < 8){
ipriv->stats[LenErrs6]++;
goto raise;
}
p = (IPICMP *)bp->rp;
pr = Fsrcvpcolx(icmp->f, p->proto);
if(pr != nil && pr->advise != nil) {
(*pr->advise)(pr, bp, msg);
return;
}
bp->rp -= IPICMPSZ;
goticmpkt6(icmp, bp, 0);
break;
case TimeExceedV6:
if(p->code == 0){
sprint(m2, "ttl exceeded at %I", p->src);
bp->rp += IPICMPSZ;
if(blocklen(bp) < 8){
ipriv->stats[LenErrs6]++;
goto raise;
}
p = (IPICMP *)bp->rp;
pr = Fsrcvpcolx(icmp->f, p->proto);
if(pr != nil && pr->advise != nil) {
(*pr->advise)(pr, bp, m2);
return;
}
bp->rp -= IPICMPSZ;
}
goticmpkt6(icmp, bp, 0);
break;
case RouterAdvert:
case RouterSolicit:
goticmpkt6(icmp, bp, p->type);
break;
case NbrSolicit:
np = (Ndpkt*)p;
pktflags = 0;
if(ifc->sendra6)
pktflags |= Rflag;
switch (targettype(icmp->f, ifc, np->target)) {
case Tunirany:
pktflags |= Oflag;
/* fall through */
case Tuniproxy:
if(ipv6local(ifc, ia, np->src)) {
if(arpenter(icmp->f, V6, np->src, np->lnaddr, 8*np->olen-2, ia, ifc, 0) < 0)
break;
pktflags |= Sflag;
} else
ipmove(ia, np->target);
icmpna(icmp->f, ia, (pktflags & Sflag)? np->src: v6allnodesL,
np->target, ifc->mac, pktflags);
break;
case Tunitent:
/*
* not clear what needs to be done. send up
* an icmp mesg saying don't use this address?
*/
break;
}
freeblist(bp);
break;
case NbrAdvert:
np = (Ndpkt*)p;
/*
* if the target address matches one of the local interface
* addresses and the local interface address has tentative bit
* set, insert into ARP table. this is so the duplicate address
* detection part of ipconfig can discover duplication through
* the arp table.
*/
lifc = iplocalonifc(ifc, np->target);
if(lifc != nil && lifc->tentative)
arpenter(icmp->f, V6, np->target, np->lnaddr, 8*np->olen-2, np->target, ifc, 0);
else if(ipv6local(ifc, ia, np->target))
arpenter(icmp->f, V6, np->target, np->lnaddr, 8*np->olen-2, ia, ifc, 1);
freeblist(bp);
break;
case PacketTooBigV6:
default:
goticmpkt6(icmp, bp, 0);
break;
}
return;
raise:
freeblist(bp);
}
static int
icmpstats6(Proto *icmp6, char *buf, int len)
{
Icmppriv6 *priv;
char *p, *e;
int i;
priv = icmp6->priv;
p = buf;
e = p+len;
for(i = 0; i < Nstats6; i++)
p = seprint(p, e, "%s: %lud\n", statnames6[i], priv->stats[i]);
for(i = 0; i <= Maxtype6; i++)
if(icmpnames6[i])
p = seprint(p, e, "%s: %lud %lud\n", icmpnames6[i],
priv->in[i], priv->out[i]);
return p - buf;
}
/* import from icmp.c */
extern int icmpstate(Conv *c, char *state, int n);
extern char* icmpannounce(Conv *c, char **argv, int argc);
extern char* icmpconnect(Conv *c, char **argv, int argc);
extern void icmpclose(Conv *c);
static void
icmpclose6(Conv *c)
{
Icmpcb6 *icb = (Icmpcb6*)c->ptcl;
icb->headers = 0;
icmpclose(c);
}
void
icmp6init(Fs *fs)
{
Proto *icmp6 = smalloc(sizeof(Proto));
icmp6->priv = smalloc(sizeof(Icmppriv6));
icmp6->name = "icmpv6";
icmp6->connect = icmpconnect;
icmp6->announce = icmpannounce;
icmp6->state = icmpstate;
icmp6->create = icmpcreate6;
icmp6->close = icmpclose6;
icmp6->rcv = icmpiput6;
icmp6->stats = icmpstats6;
icmp6->ctl = icmpctl6;
icmp6->advise = icmpadvise6;
icmp6->gc = nil;
icmp6->ipproto = ICMPv6;
icmp6->nc = 16;
icmp6->ptclsize = sizeof(Icmpcb6);
Fsproto(fs, icmp6);
}