ref: f24038d601ebe23a213ca1eaf2cf2faa47c22873
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,
};
/* icmpv6 unreachability codes */
enum {
Icmp6_no_route = 0,
Icmp6_ad_prohib = 1,
Icmp6_out_src_scope = 2,
Icmp6_adr_unreach = 3,
Icmp6_port_unreach = 4,
Icmp6_gress_src_fail = 5,
Icmp6_rej_route = 6,
Icmp6_unknown = 7, /* our own invention for internal use */
};
enum {
MinAdvise = IP6HDR+4, /* minimum needed for us to advise another protocol */
};
/* 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[]; /* link-layer address */
};
typedef struct Icmppriv6
{
ulong stats[Nstats6];
/* message counts */
ulong in[Maxtype6+1];
ulong out[Maxtype6+1];
} Icmppriv6;
typedef struct Icmpcb6
{
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);
int n = blocklen(bp);
hnputl(p->vcf, 0); /* borrow IP header as pseudoheader */
hnputs(p->ploadlen, n - IP6HDR);
p->proto = 0;
p->ttl = ICMPv6; /* ttl gets set later */
hnputs(p->cksum, 0);
hnputs(p->cksum, ptclcsum(bp, 0, n));
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, Ipifc *, 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(BLEN(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);
if(p->type <= Maxtype6)
ipriv->out[p->type]++;
ipoput6(c->p->f, bp, nil, 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, Ipifc *ifc, 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)
if(!islinklocal(s->laddr) || iplocalonifc(ifc, s->laddr) != nil)
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, 0, 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
icmpns6(Fs *f, uchar* src, int suni, uchar* targ, int tuni, uchar* mac, int maclen)
{
Block *nbp;
Ndpkt *np;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
int olen = (2+maclen+7)/8;
nbp = newIPICMP(NDISCSZ + olen*8);
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 = olen;
memmove(np->lnaddr, mac, maclen);
} else
nbp->wp -= olen*8;
set_cksum(nbp);
ipriv->out[NbrSolicit]++;
netlog(f, Logicmp, "sending neighbor solicitation %I\n", targ);
ipoput6(f, nbp, nil, MAXTTL, DFLTTOS, nil);
}
/*
* sends out an ICMPv6 neighbor advertisement. pktflags == RSO flags.
*/
void
icmpna6(Fs *f, uchar* src, uchar* dst, uchar* targ, uchar* mac, int maclen, uchar flags)
{
Block *nbp;
Ndpkt *np;
Proto *icmp = f->t2p[ICMPv6];
Icmppriv6 *ipriv = icmp->priv;
int olen = (2+maclen+7)/8;
nbp = newIPICMP(NDISCSZ + olen*8);
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 = olen;
memmove(np->lnaddr, mac, maclen);
set_cksum(nbp);
ipriv->out[NbrAdvert]++;
netlog(f, Logicmp, "sending neighbor advertisement %I\n", targ);
ipoput6(f, nbp, nil, MAXTTL, DFLTTOS, nil);
}
/*
* Send a ICMPv6 packet back of type/code/arg in response to packet bp
* which was received on ifc. The route hint rh is valid for the
* reverse route.
*/
static void
icmpsend6(Fs *f, Ipifc *ifc, Block *bp, int type, int code, int arg, Routehint *rh)
{
Proto *icmp;
uchar ia[IPaddrlen];
Ip6hdr *p;
Block *nbp;
IPICMP *np;
int sz, osz;
osz = BLEN(bp);
if(osz < IP6HDR)
return;
p = (Ip6hdr *)bp->rp;
if(isv6mcast(p->dst) || isv6mcast(p->src) || !ipv6local(ifc, ia, 0, p->src))
return;
netlog(f, Logicmp, "icmpsend6 %s (%d) %d ia %I -> src %I dst %I\n",
icmpnames6[type], type, code, ia, p->src, p->dst);
sz = MIN(IPICMPSZ + osz, v6MINTU);
nbp = newIPICMP(sz);
np = (IPICMP *)nbp->rp;
ipmove(np->src, ia);
ipmove(np->dst, p->src);
np->type = type;
np->code = code;
hnputs(np->icmpid, 0);
hnputs(np->seq, arg);
memmove(nbp->rp + IPICMPSZ, bp->rp, sz - IPICMPSZ);
set_cksum(nbp);
icmp = f->t2p[ICMPv6];
((Icmppriv6*)icmp->priv)->out[type]++;
if(rh != nil && rh->r != nil && (rh->r->type & Runi) != 0){
np = (IPICMP *)nbp->rp;
np->vcf[0] = IP_VER6 | DFLTTOS>>4;
np->vcf[1] = DFLTTOS<<4;
np->ttl = MAXTTL;
(*icmp->rcv)(icmp, ifc, nbp);
return;
}
ipoput6(f, nbp, nil, MAXTTL, DFLTTOS, rh);
}
void
icmpnohost6(Fs *f, Ipifc *ifc, Block *bp, Routehint *rh)
{
icmpsend6(f, ifc, bp, UnreachableV6, Icmp6_adr_unreach, 0, rh);
}
void
icmpnoconv6(Fs *f, Ipifc *ifc, Block *bp)
{
icmpsend6(f, ifc, bp, UnreachableV6, Icmp6_port_unreach, 0, nil);
}
void
icmpttlexceeded6(Fs *f, Ipifc *ifc, Block *bp)
{
icmpsend6(f, ifc, bp, TimeExceedV6, 0, 0, nil);
}
void
icmppkttoobig6(Fs *f, Ipifc *ifc, Block *bp, int mtu)
{
icmpsend6(f, ifc, bp, PacketTooBigV6, 0, mtu, nil);
}
/*
* RFC 2461, pages 39-40, pages 57-58.
*/
static int
valid(Proto *icmp, Ipifc *, Block *bp, Icmppriv6 *ipriv)
{
int sz, osz, unsp, ttl;
ulong vcf;
int pktsz = BLEN(bp);
uchar *packet = bp->rp;
IPICMP *p = (IPICMP *)packet;
Ndpkt *np;
if(pktsz < IPICMPSZ) {
ipriv->stats[HlenErrs6]++;
netlog(icmp->f, Logicmp, "icmp hlen %d\n", pktsz);
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;
}
vcf = nhgetl(p->vcf);
hnputl(p->vcf, 0); /* borrow IP header as pseudoheader */
ttl = p->ttl;
p->ttl = p->proto;
p->proto = 0;
if(ptclcsum(bp, 0, pktsz)) {
ipriv->stats[CsumErrs6]++;
netlog(icmp->f, Logicmp, "icmp checksum error\n");
goto err;
}
p->proto = p->ttl;
p->ttl = ttl;
hnputl(p->vcf, vcf);
/* 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 != MAXTTL) {
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 void
icmpiput6(Proto *icmp, Ipifc *ifc, Block *bp)
{
char *msg, m2[128];
uchar pktflags;
uchar ia[IPaddrlen];
Block *r;
IPICMP *p;
Icmppriv6 *ipriv = icmp->priv;
Iplifc *lifc;
Ndpkt* np;
Proto *pr;
bp = concatblock(bp);
p = (IPICMP*)bp->rp;
if(!valid(icmp, ifc, bp, ipriv) || p->type > Maxtype6)
goto raise;
ipriv->in[p->type]++;
switch(p->type) {
case EchoRequestV6:
r = mkechoreply6(bp, ifc);
if(r == nil)
goto raise;
ipriv->out[EchoReply]++;
ipoput6(icmp->f, r, nil, MAXTTL, DFLTTOS, nil);
break;
case UnreachableV6:
if(p->code >= nelem(unreachcode))
msg = unreachcode[Icmp6_unknown];
else
msg = unreachcode[p->code];
Advise:
bp->rp += IPICMPSZ;
if(BLEN(bp) < MinAdvise){
ipriv->stats[LenErrs6]++;
goto raise;
}
p = (IPICMP *)bp->rp;
/* get rid of fragment header if this is the first fragment */
if((p->vcf[0] & 0xF0) == IP_VER6 && p->proto == FH && BLEN(bp) >= MinAdvise+IP6FHDR && MinAdvise > IP6HDR){
Fraghdr6 *fh = (Fraghdr6*)(bp->rp + IP6HDR);
if((nhgets(fh->offsetRM) & ~7) == 0){ /* first fragment */
p->proto = fh->nexthdr;
/* copy down payload over fragment header */
bp->rp += IP6HDR;
bp->wp -= IP6FHDR;
memmove(bp->rp, bp->rp+IP6FHDR, BLEN(bp));
hnputs(p->ploadlen, BLEN(bp));
bp->rp -= IP6HDR;
}
}
if((p->vcf[0] & 0xF0) == IP_VER6 && p->proto != FH){
pr = Fsrcvpcolx(icmp->f, p->proto);
if(pr != nil && pr->advise != nil) {
netlog(icmp->f, Logicmp, "advising %s!%I -> %I: %s\n", pr->name, p->src, p->dst, msg);
(*pr->advise)(pr, bp, ifc, msg);
return;
}
}
bp->rp -= IPICMPSZ;
goticmpkt6(icmp, ifc, bp, 0);
break;
case TimeExceedV6:
if(p->code == 0){
snprint(msg = m2, sizeof m2, "ttl exceeded at %I", p->src);
goto Advise;
}
if(p->code == 1){
snprint(msg = m2, sizeof m2, "frag time exceeded at %I", p->src);
goto Advise;
}
goticmpkt6(icmp, ifc, bp, 0);
break;
case PacketTooBigV6:
snprint(msg = m2, sizeof(m2), "packet too big for %lud mtu at %I",
(ulong)nhgetl(p->icmpid), p->src);
goto Advise;
case RouterAdvert:
case RouterSolicit:
goticmpkt6(icmp, ifc, bp, p->type);
break;
case NbrSolicit:
if(ifc->m->maclen == 0)
goto raise;
np = (Ndpkt*)p;
pktflags = 0;
if(ifc->sendra6)
pktflags |= Rflag;
switch(arpforme(icmp->f, V6, np->target, np->src, ifc)){
case Runi:
pktflags |= Oflag;
/* wet floor */
case Rproxy:
if(ipv6local(ifc, ia, 0, 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);
icmpna6(icmp->f, ia, (pktflags & Sflag)? np->src: v6allnodesL,
np->target, ifc->mac, ifc->m->maclen, pktflags);
break;
}
freeblist(bp);
break;
case NbrAdvert:
if(ifc->m->maclen == 0)
goto raise;
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, 0, np->target))
arpenter(icmp->f, V6, np->target, np->lnaddr, 8*np->olen-2, ia, ifc, 1);
freeblist(bp);
break;
default:
goticmpkt6(icmp, ifc, 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);
}