diff options
Diffstat (limited to '')
| -rwxr-xr-x | tap-win32/proto.h | 60 | ||||
| -rwxr-xr-x | tap-win32/tapdrvr.c | 197 | ||||
| -rwxr-xr-x | tap-win32/types.h | 1 |
3 files changed, 254 insertions, 4 deletions
diff --git a/tap-win32/proto.h b/tap-win32/proto.h index 0390b08..894a37f 100755 --- a/tap-win32/proto.h +++ b/tap-win32/proto.h @@ -29,9 +29,11 @@ #pragma pack(1) #define IP_HEADER_SIZE 20 +#define IPV6_HEADER_SIZE 40 typedef unsigned char MACADDR [6]; typedef unsigned long IPADDR; +typedef unsigned char IPV6ADDR [16]; //----------------- // Ethernet address @@ -55,6 +57,7 @@ typedef struct MACADDR src; /* source ether addr */ # define ETH_P_IP 0x0800 /* IPv4 protocol */ +# define ETH_P_IPV6 0x86DD /* IPv6 protocol */ # define ETH_P_ARP 0x0806 /* ARP protocol */ USHORT proto; /* packet type ID field */ } ETH_HEADER, *PETH_HEADER; @@ -161,4 +164,61 @@ typedef struct { #define TCPOPT_MAXSEG 2 #define TCPOLEN_MAXSEG 4 +//------------ +// IPv6 Header +//------------ + +typedef struct { + UCHAR version_prio; + UCHAR flow_lbl[3]; + USHORT payload_len; +# define IPPROTO_ICMPV6 0x3a /* ICMP protocol v6 */ + UCHAR nexthdr; + UCHAR hop_limit; + IPV6ADDR saddr; + IPV6ADDR daddr; +} IPV6HDR; + +//-------------------------------------------- +// IPCMPv6 NS/NA Packets (RFC4443 and RFC4861) +//-------------------------------------------- + +// Neighbor Solictiation - RFC 4861, 4.3 +// (this is just the ICMPv6 part of the packet) +typedef struct { + UCHAR type; +# define ICMPV6_TYPE_NS 135 // neighbour solicitation + UCHAR code; +# define ICMPV6_CODE_0 0 // no specific sub-code for NS/NA + USHORT checksum; + ULONG reserved; + IPV6ADDR target_addr; +} ICMPV6_NS; + +// Neighbor Advertisement - RFC 4861, 4.4 + 4.6/4.6.1 +// (this is just the ICMPv6 payload) +typedef struct { + UCHAR type; +# define ICMPV6_TYPE_NA 136 // neighbour advertisement + UCHAR code; +# define ICMPV6_CODE_0 0 // no specific sub-code for NS/NA + USHORT checksum; + UCHAR rso_bits; // Router(0), Solicited(2), Ovrrd(4) + UCHAR reserved[3]; + IPV6ADDR target_addr; +// always include "Target Link-layer Address" option (RFC 4861 4.6.1) + UCHAR opt_type; +#define ICMPV6_OPTION_TLLA 2 + UCHAR opt_length; +#define ICMPV6_LENGTH_TLLA 1 // multiplied by 8 -> 1 = 8 bytes + MACADDR target_macaddr; +} ICMPV6_NA; + +// this is the complete packet with Ethernet and IPv6 headers +typedef struct { + ETH_HEADER eth; + IPV6HDR ipv6; + ICMPV6_NA icmpv6; +} ICMPV6_NA_PKT; + #pragma pack() diff --git a/tap-win32/tapdrvr.c b/tap-win32/tapdrvr.c index 506f1f6..7ab3916 100755 --- a/tap-win32/tapdrvr.c +++ b/tap-win32/tapdrvr.c @@ -1430,6 +1430,158 @@ NDIS_STATUS AdapterModify return l_Status; } +// checksum code for ICMPv6 packet, taken from dhcp.c / udp_checksum +// see RFC 4443, 2.3, and RFC 2460, 8.1 +USHORT +icmpv6_checksum (const UCHAR *buf, + const int len_icmpv6, + const UCHAR *saddr6, + const UCHAR *daddr6) +{ + USHORT word16; + ULONG sum = 0; + int i; + + // make 16 bit words out of every two adjacent 8 bit words and + // calculate the sum of all 16 bit words + for (i = 0; i < len_icmpv6; i += 2){ + word16 = ((buf[i] << 8) & 0xFF00) + ((i + 1 < len_icmpv6) ? (buf[i+1] & 0xFF) : 0); + sum += word16; + } + + // add the IPv6 pseudo header which contains the IP source and destination addresses + for (i = 0; i < 16; i += 2){ + word16 =((saddr6[i] << 8) & 0xFF00) + (saddr6[i+1] & 0xFF); + sum += word16; + } + for (i = 0; i < 16; i += 2){ + word16 =((daddr6[i] << 8) & 0xFF00) + (daddr6[i+1] & 0xFF); + sum += word16; + } + + // the next-header number and the length of the ICMPv6 packet + sum += (USHORT) IPPROTO_ICMPV6 + (USHORT) len_icmpv6; + + // keep only the last 16 bits of the 32 bit calculated sum and add the carries + while (sum >> 16) + sum = (sum & 0xFFFF) + (sum >> 16); + + // Take the one's complement of sum + return ((USHORT) ~sum); +} + +// check IPv6 packet for "is this an IPv6 Neighbor Solicitation that +// the tap driver needs to answer?" +// see RFC 4861 4.3 for the different cases +static IPV6ADDR IPV6_NS_TARGET_MCAST = + { 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x01, 0xff, 0x00, 0x00, 0x08 }; +static IPV6ADDR IPV6_NS_TARGET_UNICAST = + { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08 }; + +BOOLEAN +HandleIPv6NeighborDiscovery( TapAdapterPointer p_Adapter, UCHAR * m_Data ) +{ + const ETH_HEADER * e = (ETH_HEADER *) m_Data; + const IPV6HDR *ipv6 = (IPV6HDR *) (m_Data + sizeof (ETH_HEADER)); + const ICMPV6_NS * icmpv6_ns = (ICMPV6_NS *) (m_Data + sizeof (ETH_HEADER) + sizeof (IPV6HDR)); + ICMPV6_NA_PKT *na; + USHORT icmpv6_len, icmpv6_csum; + + // we don't really care about the destination MAC address here + // - it's either a multicast MAC, or the userland destination MAC + // but since the TAP driver is point-to-point, all packets are "for us" + + // IPv6 target address must be ff02::1::ff00:8 (multicast for + // initial NS) or fe80::1 (unicast for recurrent NUD) + if ( memcmp( ipv6->daddr, IPV6_NS_TARGET_MCAST, + sizeof(IPV6ADDR) ) != 0 && + memcmp( ipv6->daddr, IPV6_NS_TARGET_UNICAST, + sizeof(IPV6ADDR) ) != 0 ) + { + return FALSE; // wrong target address + } + + // IPv6 Next-Header must be ICMPv6 + if ( ipv6->nexthdr != IPPROTO_ICMPV6 ) + { + return FALSE; // wrong next-header + } + + // ICMPv6 type+code must be 135/0 for NS + if ( icmpv6_ns->type != ICMPV6_TYPE_NS || + icmpv6_ns->code != ICMPV6_CODE_0 ) + { + return FALSE; // wrong ICMPv6 type + } + + // ICMPv6 target address must be fe80::8 (magic) + if ( memcmp( icmpv6_ns->target_addr, IPV6_NS_TARGET_UNICAST, + sizeof(IPV6ADDR) ) != 0 ) + { + return FALSE; // not for us + } + + // packet identified, build magic response packet + + na = (ICMPV6_NA_PKT *) MemAlloc (sizeof (ICMPV6_NA_PKT), TRUE); + if ( !na ) return FALSE; + + //------------------------------------------------ + // Initialize Neighbour Advertisement reply packet + //------------------------------------------------ + + // ethernet header + na->eth.proto = htons(ETH_P_IPV6); + COPY_MAC(na->eth.dest, p_Adapter->m_MAC); + COPY_MAC(na->eth.src, p_Adapter->m_TapToUser.dest); + + // IPv6 header + na->ipv6.version_prio = ipv6->version_prio; + NdisMoveMemory( na->ipv6.flow_lbl, ipv6->flow_lbl, + sizeof(na->ipv6.flow_lbl) ); + icmpv6_len = sizeof(ICMPV6_NA_PKT) - sizeof(ETH_HEADER) - sizeof(IPV6HDR); + na->ipv6.payload_len = htons(icmpv6_len); + na->ipv6.nexthdr = IPPROTO_ICMPV6; + na->ipv6.hop_limit = 255; + NdisMoveMemory( na->ipv6.saddr, IPV6_NS_TARGET_UNICAST, + sizeof(IPV6ADDR) ); + NdisMoveMemory( na->ipv6.daddr, ipv6->saddr, + sizeof(IPV6ADDR) ); + + // ICMPv6 + na->icmpv6.type = ICMPV6_TYPE_NA; + na->icmpv6.code = ICMPV6_CODE_0; + na->icmpv6.checksum = 0; + na->icmpv6.rso_bits = 0x60; // Solicited + Override + NdisZeroMemory( na->icmpv6.reserved, sizeof(na->icmpv6.reserved) ); + NdisMoveMemory( na->icmpv6.target_addr, IPV6_NS_TARGET_UNICAST, + sizeof(IPV6ADDR) ); + + // ICMPv6 option "Target Link Layer Address" + na->icmpv6.opt_type = ICMPV6_OPTION_TLLA; + na->icmpv6.opt_length = ICMPV6_LENGTH_TLLA; + COPY_MAC( na->icmpv6.target_macaddr, p_Adapter->m_TapToUser.dest ); + + // calculate and set checksum + icmpv6_csum = icmpv6_checksum ( (UCHAR*) &(na->icmpv6), + icmpv6_len, + na->ipv6.saddr, + na->ipv6.daddr ); + na->icmpv6.checksum = htons( icmpv6_csum ); + + DUMP_PACKET ("HandleIPv6NeighborDiscovery", + (unsigned char *) na, + sizeof (ICMPV6_NA_PKT)); + + InjectPacketDeferred (p_Adapter, (UCHAR *) na, sizeof (ICMPV6_NA_PKT)); + + MemFree (na, sizeof (ICMPV6_NA_PKT)); + + return TRUE; // all fine +} + //==================================================================== // Adapter Transmission //==================================================================== @@ -1566,7 +1718,10 @@ AdapterTransmit (IN NDIS_HANDLE p_AdapterContext, //=============================================== // In Point-To-Point mode, check to see whether - // packet is ARP or IPv4 (if neither, then drop). + // packet is ARP (handled) or IPv4 (sent to app). + // IPv6 packets are inspected for neighbour discovery + // (to be handled locally), and the rest is forwarded + // all other protocols are dropped //=============================================== if (l_Adapter->m_tun) { @@ -1611,6 +1766,27 @@ AdapterTransmit (IN NDIS_HANDLE p_AdapterContext, // Packet looks like IPv4, queue it. l_PacketBuffer->m_SizeFlags |= TP_TUN; + + case ETH_P_IPV6: + // make sure that packet is large + // enough to be IPv6 + if (l_PacketLength + < ETHERNET_HEADER_SIZE + IPV6_HEADER_SIZE) + goto no_queue; + + // broadcasts and multicasts are handled specially + // (to be implemented) + + // neighbor discovery packets to fe80::8 are special + // OpenVPN sets this next-hop to signal "handled by tapdrv" + if ( HandleIPv6NeighborDiscovery( l_Adapter, + l_PacketBuffer->m_Data )) + { + goto no_queue; + } + + // Packet looks like IPv6, queue it :-) + l_PacketBuffer->m_SizeFlags |= TP_TUN; } } @@ -1902,6 +2078,8 @@ TapDeviceHook (IN PDEVICE_OBJECT p_DeviceObject, IN PIRP p_IRP) COPY_MAC (l_Adapter->m_UserToTap.dest, l_Adapter->m_MAC); l_Adapter->m_TapToUser.proto = l_Adapter->m_UserToTap.proto = htons (ETH_P_IP); + l_Adapter->m_UserToTap_IPv6 = l_Adapter->m_UserToTap; + l_Adapter->m_UserToTap_IPv6.proto = htons(ETH_P_IPV6); l_Adapter->m_tun = TRUE; @@ -1939,6 +2117,8 @@ TapDeviceHook (IN PDEVICE_OBJECT p_DeviceObject, IN PIRP p_IRP) COPY_MAC (l_Adapter->m_UserToTap.dest, l_Adapter->m_MAC); l_Adapter->m_TapToUser.proto = l_Adapter->m_UserToTap.proto = htons (ETH_P_IP); + l_Adapter->m_UserToTap_IPv6 = l_Adapter->m_UserToTap; + l_Adapter->m_UserToTap_IPv6.proto = htons(ETH_P_IPV6); l_Adapter->m_tun = TRUE; @@ -2236,10 +2416,18 @@ TapDeviceHook (IN PDEVICE_OBJECT p_DeviceObject, IN PIRP p_IRP) { __try { + ETH_HEADER * p_UserToTap = &l_Adapter->m_UserToTap; + + // for IPv6, need to use ethernet header with IPv6 proto + if ( IPH_GET_VER( ((IPHDR*) p_IRP->AssociatedIrp.SystemBuffer)->version_len) == 6 ) + { + p_UserToTap = &l_Adapter->m_UserToTap_IPv6; + } + p_IRP->IoStatus.Information = l_IrpSp->Parameters.Write.Length; DUMP_PACKET2 ("IRP_MJ_WRITE P2P", - &l_Adapter->m_UserToTap, + p_UserToTap, (unsigned char *) p_IRP->AssociatedIrp.SystemBuffer, l_IrpSp->Parameters.Write.Length); @@ -2258,8 +2446,8 @@ TapDeviceHook (IN PDEVICE_OBJECT p_DeviceObject, IN PIRP p_IRP) NdisMEthIndicateReceive (l_Adapter->m_MiniportAdapterHandle, (NDIS_HANDLE) l_Adapter, - (unsigned char *) &l_Adapter->m_UserToTap, - sizeof (l_Adapter->m_UserToTap), + (unsigned char *) p_UserToTap, + sizeof (ETH_HEADER), (unsigned char *) p_IRP->AssociatedIrp.SystemBuffer, l_IrpSp->Parameters.Write.Length, l_IrpSp->Parameters.Write.Length); @@ -2820,6 +3008,7 @@ VOID ResetTapAdapterState (TapAdapterPointer p_Adapter) p_Adapter->m_remoteNetmask = 0; NdisZeroMemory (&p_Adapter->m_TapToUser, sizeof (p_Adapter->m_TapToUser)); NdisZeroMemory (&p_Adapter->m_UserToTap, sizeof (p_Adapter->m_UserToTap)); + NdisZeroMemory (&p_Adapter->m_UserToTap_IPv6, sizeof (p_Adapter->m_UserToTap_IPv6)); // DHCP Masq p_Adapter->m_dhcp_enabled = FALSE; diff --git a/tap-win32/types.h b/tap-win32/types.h index 9406252..bdc08e7 100755 --- a/tap-win32/types.h +++ b/tap-win32/types.h @@ -143,6 +143,7 @@ typedef struct _TapAdapter IPADDR m_remoteNetmask; ETH_HEADER m_TapToUser; ETH_HEADER m_UserToTap; + ETH_HEADER m_UserToTap_IPv6; // same as UserToTap but proto=ipv6 MACADDR m_MAC_Broadcast; // Used for DHCP server masquerade |