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Add some error handling and other fixes to icmpv6.go
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@ -6,6 +6,7 @@ package yggdrasil
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import "golang.org/x/net/icmp"
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import "encoding/binary"
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import "errors"
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import "unsafe" // TODO investigate if this can be done without resorting to unsafe
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type macAddress [6]byte
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@ -89,54 +90,77 @@ func (i *icmpv6) listen() {
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if i.tun.iface.IsTAP() {
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// TAP mode
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dataout := make([]byte, ETHER+IPV6+32)
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i.read_tap(datain, dataout)
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i.tun.iface.Write(dataout)
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response, err := i.parse_packet_tap(datain)
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if err != nil {
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i.tun.core.log.Printf("Error from icmpv6.parse_packet_tap: %v", err)
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continue
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}
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if response != nil {
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i.tun.iface.Write(response)
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}
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} else {
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// TUN mode
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dataout := make([]byte, IPV6+32)
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i.read_tun(datain, dataout)
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i.tun.iface.Write(dataout)
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response, err := i.parse_packet_tun(datain)
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if err != nil {
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i.tun.core.log.Printf("Error from icmpv6.parse_packet_tun: %v", err)
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continue
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}
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if response != nil {
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i.tun.iface.Write(response)
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}
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}
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}
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}
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func (i *icmpv6) read_tap(datain []byte, dataout []byte) {
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func (i *icmpv6) parse_packet_tap(datain []byte) ([]byte, error) {
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// Set up
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in := (*icmpv6Frame)(unsafe.Pointer(&datain[0]))
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out := (*icmpv6Frame)(unsafe.Pointer(&dataout[0]))
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// Store the peer MAC address
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copy(i.peermac[:6], in.ether.source[:6])
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// Ignore non-IPv6 frames
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if binary.BigEndian.Uint16(in.ether.ethertype[:]) != uint16(0x86DD) {
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return
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return nil, nil
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}
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// Populate the out ethernet headers
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// Create the response buffer
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dataout := make([]byte, ETHER+IPV6+32)
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out := (*icmpv6Frame)(unsafe.Pointer(&dataout[0]))
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// Populate the response ethernet headers
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copy(out.ether.destination[:], in.ether.destination[:])
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copy(out.ether.source[:], i.mymac[:])
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binary.BigEndian.PutUint16(out.ether.ethertype[:], uint16(0x86DD))
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// And for now just copy the rest of the packet we were sent
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copy(dataout[ETHER:ETHER+IPV6], datain[ETHER:ETHER+IPV6])
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// Hand over to parse_packet_tun to interpret the IPv6 packet
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ipv6packet, err := i.parse_packet_tun(datain)
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if err != nil {
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return nil, nil
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}
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// Then pass the IP packet onto the next function
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i.read_tun(datain[ETHER:], dataout[ETHER:])
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// Copy the returned packet to our response ethernet frame
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if ipv6packet != nil {
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copy(dataout[ETHER:ETHER+IPV6], ipv6packet)
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return dataout, nil
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}
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// At this point there is no response to send back
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return nil, nil
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}
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func (i *icmpv6) read_tun(datain []byte, dataout []byte) {
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func (i *icmpv6) parse_packet_tun(datain []byte) ([]byte, error) {
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// Set up
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in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
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dataout := make([]byte, IPV6+32)
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out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
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in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
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// Store the peer link-local address
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copy(i.peerlladdr[:16], in.ipv6.source[:16])
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// Ignore non-ICMPv6 packets
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if in.ipv6.nextheader != uint8(0x3A) {
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return
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return nil, nil
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}
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// What is the ICMPv6 message type?
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@ -155,10 +179,16 @@ func (i *icmpv6) read_tun(datain []byte, dataout []byte) {
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copy(dataout[IPV6:], datain[IPV6:])
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// Calculate the checksum
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i.calculate_checksum(dataout)
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err := i.calculate_checksum(dataout)
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if err != nil {
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return nil, err
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}
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// Return the response packet
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return dataout, nil
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}
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func (i *icmpv6) calculate_checksum(dataout []byte) {
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func (i *icmpv6) calculate_checksum(dataout []byte) (error) {
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// Set up
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out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
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@ -173,15 +203,18 @@ func (i *icmpv6) calculate_checksum(dataout []byte) {
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// Lazy-man's checksum using the icmp library
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icmpv6, err := icmp.ParseMessage(0x3A, dataout[IPV6:])
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if err != nil {
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return
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return err
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}
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// And copy the payload
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payload, err := icmpv6.Marshal(ps)
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if err != nil {
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return
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return err
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}
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copy(dataout[IPV6:], payload)
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// Return nil if successful
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return nil
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}
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func (i *icmpv6) handle_ndp(in *icmpv6Payload, out *icmpv6Payload) {
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