void Connection::segment_arrived(TCP::Packet_ptr incoming) {
signal_packet_received(incoming);
if(incoming->has_options()) {
try {
parse_options(incoming);
}
catch(TCPBadOptionException err) {
debug("<TCP::Connection::receive> %s \n", err.what());
}
}
// Let state handle what to do when incoming packet arrives, and modify the outgoing packet.
switch(state_->handle(*this, incoming)) {
case State::OK: {
// Do nothing.
break;
}
case State::CLOSED: {
debug("<TCP::Connection::receive> (%s => %s) State handle finished with CLOSED. We're done, ask host() to delete the connection.\n",
prev_state_->to_string().c_str(), state_->to_string().c_str());
writeq_reset();
signal_close();
break;
};
case State::CLOSE: {
debug("<TCP::Connection::receive> State handle finished with CLOSE. onDisconnect has been called, close the connection. \n");
state_->close(*this);
break;
};
}
}
void Connection::parse_options(TCP::Packet_ptr packet) {
assert(packet->has_options());
debug("<TCP::parse_options> Parsing options. Offset: %u, Options: %u \n",
packet->offset(), packet->options_length());
auto* opt = packet->options();
while((char*)opt < packet->data()) {
auto* option = (TCP::Option*)opt;
switch(option->kind) {
case Option::END: {
return;
}
case Option::NOP: {
opt++;
break;
}
case Option::MSS: {
// unlikely
if(option->length != 4)
throw TCPBadOptionException{Option::MSS, "length != 4"};
// unlikely
if(!packet->isset(SYN))
throw TCPBadOptionException{Option::MSS, "Non-SYN packet"};
auto* opt_mss = (Option::opt_mss*)option;
uint16_t mss = ntohs(opt_mss->mss);
cb.SND.MSS = mss;
debug2("<TCP::parse_options@Option:MSS> MSS: %u \n", mss);
opt += option->length;
break;
}
default:
return;
}
}
}