57 lines
1.4 KiB
Go
57 lines
1.4 KiB
Go
package arpdis
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// Reference: github.com/malfunkt/arpfox
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// TODO now only support IPv4
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import (
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"github.com/google/gopacket"
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"github.com/google/gopacket/layers"
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)
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var defaultSerializeOpts = gopacket.SerializeOptions{
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FixLengths: true,
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ComputeChecksums: true,
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}
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// NewARPRequest creates a bew ARP packet of type "request.
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func NewARPRequest(src *Addr, dst *Addr) ([]byte, error) {
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return buildPacket(src, dst, layers.ARPRequest)
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}
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// NewARPReply creates a new ARP packet of type "reply".
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func NewARPReply(src *Addr, dst *Addr) ([]byte, error) {
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return buildPacket(src, dst, layers.ARPReply)
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}
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// buildPacket creates an template ARP packet with the given source and
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// destination.
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func buildPacket(src *Addr, dst *Addr, opt uint16) ([]byte, error) {
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ether := layers.Ethernet{
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EthernetType: layers.EthernetTypeARP,
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SrcMAC: src.HardwareAddr,
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DstMAC: dst.HardwareAddr,
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}
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arp := layers.ARP{
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AddrType: layers.LinkTypeEthernet,
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Protocol: layers.EthernetTypeIPv4,
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HwAddressSize: 6,
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ProtAddressSize: 4,
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Operation: opt,
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SourceHwAddress: src.HardwareAddr,
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SourceProtAddress: src.IP.To4(),
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DstHwAddress: dst.HardwareAddr,
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DstProtAddress: dst.IP.To4(),
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}
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buf := gopacket.NewSerializeBuffer()
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err := gopacket.SerializeLayers(buf, defaultSerializeOpts, ðer, &arp)
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if err != nil {
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return nil, err
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}
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return buf.Bytes(), nil
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}
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