renet
/
renet
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

tcp: Make initial sequence number random.

master
Dario Nieuwenhuis 2021-10-11 20:21:40 +02:00
parent 17e0ddcee3
commit 61293b2cb2
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
src/socket/tcp.rs
View File

@ -56,11 +56,6 @@ impl fmt::Display for State {
}
}
/// Initial sequence number. This used to be 0, but some servers don't behave correctly
/// with that, so we use a non-zero starting sequence number. TODO: randomize instead.
/// https://github.com/smoltcp-rs/smoltcp/issues/489
const INITIAL_SEQ_NO: TcpSeqNumber = TcpSeqNumber(42);
// Conservative initial RTT estimate.
const RTTE_INITIAL_RTT: u32 = 300;
const RTTE_INITIAL_DEV: u32 = 100;
@ -430,7 +425,7 @@ impl<'a> TcpSocket<'a> {
listen_address: IpAddress::default(),
local_endpoint: IpEndpoint::default(),
remote_endpoint: IpEndpoint::default(),
local_seq_no: INITIAL_SEQ_NO,
local_seq_no: TcpSeqNumber::default(),
remote_seq_no: TcpSeqNumber::default(),
remote_last_seq: TcpSeqNumber::default(),
remote_last_ack: None,
@ -658,7 +653,7 @@ impl<'a> TcpSocket<'a> {
self.listen_address = IpAddress::default();
self.local_endpoint = IpEndpoint::default();
self.remote_endpoint = IpEndpoint::default();
self.local_seq_no = INITIAL_SEQ_NO;
self.local_seq_no = TcpSeqNumber::default();
self.remote_seq_no = TcpSeqNumber::default();
self.remote_last_seq = TcpSeqNumber::default();
self.remote_last_ack = None;
@ -751,18 +746,24 @@ impl<'a> TcpSocket<'a> {
..local_endpoint
};
// Carry over the local sequence number.
let local_seq_no = self.local_seq_no;
self.reset();
self.local_endpoint = local_endpoint;
self.remote_endpoint = remote_endpoint;
self.local_seq_no = local_seq_no;
self.remote_last_seq = local_seq_no;
self.set_state(State::SynSent);
let seq = Self::random_seq_no();
self.local_seq_no = seq;
self.remote_last_seq = seq;
Ok(())
}
fn random_seq_no() -> TcpSeqNumber {
#[cfg(test)]
return TcpSeqNumber(10000);
#[cfg(not(test))]
return TcpSeqNumber(crate::rand::rand_u32() as i32);
}
/// Close the transmit half of the full-duplex connection.
///
/// Note that there is no corresponding function for the receive half of the full-duplex
@ -1575,8 +1576,7 @@ impl<'a> TcpSocket<'a> {
self.local_endpoint = IpEndpoint::new(ip_repr.dst_addr(), repr.dst_port);
self.remote_endpoint = IpEndpoint::new(ip_repr.src_addr(), repr.src_port);
// FIXME: use something more secure here
self.local_seq_no = TcpSeqNumber(!repr.seq_number.0);
self.local_seq_no = Self::random_seq_no();
self.remote_seq_no = repr.seq_number + 1;
self.remote_last_seq = self.local_seq_no;
self.remote_has_sack = repr.sack_permitted;