void parse_ipv4(packet_in b, Parsed_packet p)
{
b.extract <Ipv4_h>(out p.ip);
vss_model.VSSModel.verify((p.ip.version == 4), error.IPv4IncorrectVersion);
vss_model.VSSModel.verify((p.ip.ihl == 5), error.IPv4OptionsNotSupported);
ck.clear();
ck.update <Ipv4_h>(p.ip);
vss_model.VSSModel.verify((ck.get() == 0), error.IPv4ChecksumError);
accept(b, p);
}
private void parse_ipv4(packet_in b, Parsed_packet p)
{
b.extract(out p.ip);
verify.apply(p.ip.version == (bit4)4, new IPv4IncorrectVersion()); // FIXME how are we handling errors? D: NOTE P4 gives it as error.IPV4IncorrectVersion
verify.apply(p.ip.ihl == (bit4)5, new IPv4OptionsNotSupported());
ck.clear();
ck.update(p.ip);
verify.apply(ck.get() == (bit16)0, new IPv4ChecksumError());
// transition accept
}
void start(packet_in b, Parsed_packet p)
{
b.extract <Ethernet_h>(out p.ethernet);
switch ((System.UInt16)p.ethernet.etherType)
{
case 0x800:
parse_ipv4(b, p);
break;
}
}
private void start(packet_in b, Parsed_packet p)
{
// NOTE type unknown and no type arg specified
b.extract(out p.ethernet); // NOTE P4 doesn't specify direction of argument, only of parameter at declaration (i.e. not at call site)
switch (p.ethernet.etherType.Value) // NOTE P4 doesn't specify value
{
case 0x0800: // InfInt
return(parse_ipv4(b, p)); // NOTE P4 just gives us parse_ipv4 - could it also give us more args?
break;
default: parseError = error.NoMatch; // no default rule: all other packets rejected FIXME do we need to generate code for this?
}
}