diff options
Diffstat (limited to 'node/Switch.cpp')
| -rw-r--r-- | node/Switch.cpp | 85 |
1 files changed, 72 insertions, 13 deletions
diff --git a/node/Switch.cpp b/node/Switch.cpp index b7a9c522..97befbc6 100644 --- a/node/Switch.cpp +++ b/node/Switch.cpp @@ -154,25 +154,84 @@ void Switch::onLocalEthernet(const SharedPtr<Network> &network,const MAC &from,c MulticastGroup mg(to,0); if (to.isBroadcast()) { - if ( - (etherType == ZT_ETHERTYPE_ARP)&& - (len >= 28)&& - ( - (((const unsigned char *)data)[2] == 0x08)&& - (((const unsigned char *)data)[3] == 0x00)&& - (((const unsigned char *)data)[4] == 6)&& - (((const unsigned char *)data)[5] == 4)&& - (((const unsigned char *)data)[7] == 0x01) - ) - ) { - // Cram IPv4 IP into ADI field to make IPv4 ARP broadcast channel specific and scalable - // Also: enableBroadcast() does not apply to ARP since it's required for IPv4 + if ( (etherType == ZT_ETHERTYPE_ARP) && (len >= 28) && ((((const uint8_t *)data)[2] == 0x08)&&(((const uint8_t *)data)[3] == 0x00)&&(((const uint8_t *)data)[4] == 6)&&(((const uint8_t *)data)[5] == 4)&&(((const uint8_t *)data)[7] == 0x01)) ) { + /* IPv4 ARP is one of the few special cases that we impose upon what is + * otherwise a straightforward Ethernet switch emulation. Vanilla ARP + * is dumb old broadcast and simply doesn't scale. ZeroTier multicast + * groups have an additional field called ADI (additional distinguishing + * information) which was added specifically for ARP though it could + * be used for other things too. We then take ARP broadcasts and turn + * them into multicasts by stuffing the IP address being queried into + * the 32-bit ADI field. In practice this uses our multicast pub/sub + * system to implement a kind of extended/distributed ARP table. */ mg = MulticastGroup::deriveMulticastGroupForAddressResolution(InetAddress(((const unsigned char *)data) + 24,4,0)); } else if (!nconf->enableBroadcast()) { // Don't transmit broadcasts if this network doesn't want them TRACE("%.16llx: dropped broadcast since ff:ff:ff:ff:ff:ff is not enabled",network->id()); return; } + } else if ((etherType == ZT_ETHERTYPE_IPV6)&&(len >= (40 + 8 + 16))) { + /* IPv6 NDP emulation on ZeroTier-RFC4193 addressed networks! This allows + * for multicast-free operation in IPv6 networks, which both improves + * performance and is friendlier to mobile and (especially) IoT devices. + * In the future there may be a no-multicast build option for embedded + * and IoT use and this will be the preferred addressing mode. Note that + * it plays nice with our L2 emulation philosophy and even with bridging. + * While "real" devices behind the bridge can't have ZT-RFC4193 addresses + * themselves, they can look these addresses up with NDP and it will + * work just fine. */ + if ((reinterpret_cast<const uint8_t *>(data)[6] == 0x3a)&&(reinterpret_cast<const uint8_t *>(data)[40] == 0x87)) { // ICMPv6 neighbor solicitation + for(std::vector<InetAddress>::const_iterator sip(nconf->staticIps().begin()),sipend(nconf->staticIps().end());sip!=sipend;++sip) { + if ((sip->ss_family == AF_INET6)&&(Utils::ntoh((uint16_t)reinterpret_cast<const struct sockaddr_in6 *>(&(*sip))->sin6_port) == 88)) { + const uint8_t *my6 = reinterpret_cast<const uint8_t *>(reinterpret_cast<const struct sockaddr_in6 *>(&(*sip))->sin6_addr.s6_addr); + if ((my6[0] == 0xfd)&&(my6[9] == 0x99)&&(my6[10] == 0x93)) { // ZT-RFC4193 == fd__:____:____:____:__99:93__:____:____ / 88 + const uint8_t *pkt6 = reinterpret_cast<const uint8_t *>(data) + 40 + 8; + unsigned int ptr = 0; + while (ptr != 11) { + if (pkt6[ptr] != my6[ptr]) + break; + ++ptr; + } + if (ptr == 11) { // /88 matches an assigned address on this network + const Address atPeer(pkt6 + ptr,5); + if (atPeer != RR->identity.address()) { + const MAC atPeerMac(atPeer,network->id()); + TRACE("ZT-RFC4193 NDP emulation: %.16llx: forging response for %s/%s",network->id(),atPeer.toString().c_str(),atPeerMac.toString().c_str()); + + uint8_t adv[72]; + adv[0] = 0x60; adv[1] = 0x00; adv[2] = 0x00; adv[3] = 0x00; + adv[4] = 0x00; adv[5] = 0x20; + adv[6] = 0x3a; adv[7] = 0xff; + for(int i=0;i<16;++i) adv[8 + i] = pkt6[i]; + for(int i=0;i<16;++i) adv[24 + i] = my6[i]; + adv[40] = 0x88; adv[41] = 0x00; + adv[42] = 0x00; adv[43] = 0x00; // future home of checksum + adv[44] = 0x60; adv[45] = 0x00; adv[46] = 0x00; adv[47] = 0x00; + for(int i=0;i<16;++i) adv[48 + i] = pkt6[i]; + adv[64] = 0x02; adv[65] = 0x01; + adv[66] = atPeerMac[0]; adv[67] = atPeerMac[1]; adv[68] = atPeerMac[2]; adv[69] = atPeerMac[3]; adv[70] = atPeerMac[4]; adv[71] = atPeerMac[5]; + + uint16_t pseudo_[36]; + uint8_t *const pseudo = reinterpret_cast<uint8_t *>(pseudo_); + for(int i=0;i<32;++i) pseudo[i] = adv[8 + i]; + pseudo[32] = 0x00; pseudo[33] = 0x00; pseudo[34] = 0x00; pseudo[35] = 0x20; + pseudo[36] = 0x00; pseudo[37] = 0x00; pseudo[38] = 0x00; pseudo[39] = 0x3a; + for(int i=0;i<32;++i) pseudo[40 + i] = adv[40 + i]; + uint32_t checksum = 0; + for(int i=0;i<36;++i) checksum += Utils::hton(pseudo_[i]); + while ((checksum >> 16)) checksum = (checksum & 0xffff) + (checksum >> 16); + checksum = ~checksum; + adv[42] = (checksum >> 8) & 0xff; + adv[43] = checksum & 0xff; + + RR->node->putFrame(network->id(),atPeerMac,from,ZT_ETHERTYPE_IPV6,0,adv,72); + return; // stop processing: we have handled this frame with a spoofed local reply so no need to send it anywhere + } + } + } + } + } + } } /* Learn multicast groups for bridged-in hosts. |