private static bool TryReadEntry(byte[] buffer, int payloadOffset, int payloadLength, GreSourceRouteEntryAddressFamily addressFamily, int offsetInPayload, out GreSourceRouteEntry entry)
{
entry = null;
switch (addressFamily)
{
case GreSourceRouteEntryAddressFamily.IpSourceRoute:
if (offsetInPayload % IpV4Address.SizeOf != 0 || payloadLength % IpV4Address.SizeOf != 0)
{
return(false);
}
int numAddresses = payloadLength / IpV4Address.SizeOf;
IpV4Address[] addresses = new IpV4Address[numAddresses];
for (int i = 0; i != numAddresses; ++i)
{
addresses[i] = buffer.ReadIpV4Address(payloadOffset + i * IpV4Address.SizeOf, Endianity.Big);
}
entry = new GreSourceRouteEntryIp(addresses, offsetInPayload / IpV4Address.SizeOf);
return(true);
case GreSourceRouteEntryAddressFamily.AsSourceRoute:
if (offsetInPayload % sizeof(ushort) != 0 || payloadLength % sizeof(ushort) != 0)
{
return(false);
}
int numAsNumbers = payloadLength / sizeof(ushort);
ushort[] asNumbers = new ushort[numAsNumbers];
for (int i = 0; i != numAsNumbers; ++i)
{
asNumbers[i] = buffer.ReadUShort(payloadOffset + i * sizeof(ushort), Endianity.Big);
}
entry = new GreSourceRouteEntryAs(asNumbers, offsetInPayload / sizeof(ushort));
return(true);
default:
Datagram data = new Datagram(buffer, payloadOffset, payloadLength);
entry = new GreSourceRouteEntryUnknown(addressFamily, data, offsetInPayload);
return(true);
}
}
public static GreLayer NextGreLayer(this Random random)
{
GreVersion version = random.NextEnum<GreVersion>();
bool isChecksum = random.NextBool();
GreSourceRouteEntry[] routing = null;
ushort? routingOffset = null;
bool strictSourceRoute = false;
EthernetType protocolType = random.NextEnum(EthernetType.None);
uint? key = random.NextBool() ? (uint?)random.NextUInt() : null;
if (version == GreVersion.Gre)
{
if (random.NextBool())
{
strictSourceRoute = random.NextBool();
routing = new GreSourceRouteEntry[random.Next(5)];
GreSourceRouteEntryAddressFamily family;
if (random.NextBool())
family = random.NextEnum(GreSourceRouteEntryAddressFamily.None);
else
family = (GreSourceRouteEntryAddressFamily)random.NextUShort();
for (int i = 0; i != routing.Length; ++i)
{
switch (family)
{
case GreSourceRouteEntryAddressFamily.AsSourceRoute:
{
ushort[] asNumbers = ((Func<ushort>)(() => random.NextUShort())).GenerateArray(random.NextInt(1, 5));
routing[i] = new GreSourceRouteEntryAs(asNumbers.AsReadOnly(), random.Next(asNumbers.Length + 1));
break;
}
case GreSourceRouteEntryAddressFamily.IpSourceRoute:
{
IpV4Address[] ips = ((Func<IpV4Address>)(() => random.NextIpV4Address())).GenerateArray(random.NextInt(1, 5));
routing[i] = new GreSourceRouteEntryIp(ips.AsReadOnly(), random.Next(ips.Length + 1));
break;
}
default:
{
int dataLength = random.NextInt(1, 100);
routing[i] = new GreSourceRouteEntryUnknown(family, random.NextDatagram(dataLength), random.Next(dataLength + 1));
break;
}
}
}
routingOffset = 0;
if (routing.Any())
{
int routingIndex = random.Next(routing.Length);
for (int i = 0; i != routingIndex; ++i)
routingOffset += (ushort)routing[i].Length;
}
}
}
else
{
protocolType = EthernetType.PointToPointProtocol;
isChecksum = false;
key = random.NextUInt();
}
return new GreLayer
{
Version = version,
ProtocolType = protocolType,
ChecksumPresent = isChecksum,
Checksum = isChecksum && random.NextBool() ? (ushort?)random.NextUShort() : null,
Key = key,
SequenceNumber = random.NextBool() ? (uint?)random.NextUInt() : null,
AcknowledgmentSequenceNumber = version == GreVersion.EnhancedGre && random.NextBool() ? (uint?)random.NextUInt() : null,
RecursionControl = random.NextByte(8),
// Flags = random.NextByte(32),
Routing = routing == null ? null : routing.AsReadOnly(),
RoutingOffset = routingOffset,
StrictSourceRoute = strictSourceRoute,
};
}