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padd out CSMA payloads to 46 bytes if needed

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This commit is contained in:
Craig Dowell
2009-12-02 16:22:37 -08:00
parent a2c63bf818
commit aa7573e80a
1 changed files with 29 additions and 0 deletions
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29
src/devices/csma/csma-net-device.cc
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@@ -393,6 +393,20 @@ CsmaNetDevice::AddHeader (Ptr<Packet> p, Mac48Address source, Mac48Address de
// in the old Ethernet Blue Book.
//
lengthType = protocolNumber;
//
// All Ethernet frames must carry a minimum payload of 46 bytes. We need
// to pad out if we don't have enough bytes. These must be real bytes
// since they will be written to pcap files and compared in regression
// trace files.
//
if (p->GetSize () < 46)
{
uint8_t buffer[46];
memset (buffer, 0, 46);
Ptr<Packet> padd = Create<Packet> (buffer, 46 - p->GetSize ());
p->AddAtEnd (padd);
}
break;
case LLC:
{
@@ -401,6 +415,21 @@ CsmaNetDevice::AddHeader (Ptr<Packet> p, Mac48Address source, Mac48Address de
LlcSnapHeader llc;
llc.SetType (protocolNumber);
p->AddHeader (llc);
//
// All Ethernet frames must carry a minimum payload of 46 bytes. The
// LLC SNAP header counts as part of this payload. We need to padd out
// if we don't have enough bytes. These must be real bytes since they
// will be written to pcap files and compared in regression trace files.
//
if (p->GetSize () < 46)
{
uint8_t buffer[46];
memset (buffer, 0, 46);
Ptr<Packet> padd = Create<Packet> (buffer, 46 - p->GetSize ());
p->AddAtEnd (padd);
}
//
// This corresponds to the length interpretation of the lengthType field,
// but with an LLC/SNAP header added to the payload as in IEEE 802.2