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Fix 'DHCPv4 length 0 too short' error

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maride 2019-11-28 18:48:54 +01:00
parent 4bb9dad91e
commit a1281360cd
1 changed files with 8 additions and 1 deletions
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9
ethernet/dhcpv4/dhcp.go
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@ -18,8 +18,15 @@ func HandleDHCPv4Packet(packet gopacket.Packet) error {
var dhcppacket layers.DHCPv4 var dhcppacket layers.DHCPv4
var ethernetpacket layers.Ethernet var ethernetpacket layers.Ethernet
// For some reason I can't find an explanation for,
// packet.Layer(layers.LayerTypeDHCPv4).LayerContents(), which effectively is
// packet.Layers()[3].layerContents(), is empty, but
// packet.Layers()[2].layerPayload() contains the correct DHCP packet.
// ... although both calls should return the same bytes.
// TODO: Open an Issue on github.com/google/gopacket
// Decode raw packet into DHCPv4 // Decode raw packet into DHCPv4
decodeDHCPErr := dhcppacket.DecodeFromBytes(packet.Layer(layers.LayerTypeDHCPv4).LayerContents(), gopacket.NilDecodeFeedback) decodeDHCPErr := dhcppacket.DecodeFromBytes(packet.Layers()[2].LayerPayload(), gopacket.NilDecodeFeedback)
if decodeDHCPErr != nil { if decodeDHCPErr != nil {
// Encountered an error during decoding, most likely a broken packet // Encountered an error during decoding, most likely a broken packet
return decodeDHCPErr return decodeDHCPErr