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gtpv1u: check message type when decoding payload #112

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mosajjal merged 1 commit into from
May 11, 2025
Merged

gtpv1u: check message type when decoding payload #112

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3 changes: 3 additions & 0 deletions layers/gtp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -176,6 +176,9 @@ func (g *GTPv1U) NextLayerType() gopacket.LayerType {
if len(g.LayerPayload()) == 0 {
return gopacket.LayerTypeZero
}
if g.MessageType != 255 {
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@mosajjal mosajjal Apr 19, 2025

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where does this definition come from? I'm looking at 3GPP TS 29.060 section 7.1 and it doesn't align with this condition.

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@mejedi mejedi Apr 20, 2025 •
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The version you are referring to defines T-PDU (tunneled traffic such as IPv4 or IPv6) and G-PDU in section 3.

In 7.1 it says that G-PDU is message type 255.

return gopacket.LayerTypePayload
}
version := uint8(g.LayerPayload()[0]) >> 4
if version == 4 {
return LayerTypeIPv4
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