ref: 909323e92a4e694bff5908e500d8655ac1bbd932
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, }; 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[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 { 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, 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); 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, 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 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, 0, 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, 0, 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, 0, 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 *, Block *bp, Icmppriv6 *ipriv) { int sz, osz, unsp, ttl; 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; } memset(packet, 0, 4); 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; /* 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 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, 0, 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, msg); return; } } bp->rp -= IPICMPSZ; goticmpkt6(icmp, 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, 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, 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, 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); 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, 0, np->target)) arpenter(icmp->f, V6, np->target, np->lnaddr, 8*np->olen-2, ia, ifc, 1); freeblist(bp); break; 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); }