Search for ports sequentially instead of at random for more predictable port selection

This commit is contained in:
Michael Vines 2020-04-09 13:35:23 -07:00
parent 91159ea8e3
commit 032127b591
1 changed files with 20 additions and 40 deletions

View File

@ -261,54 +261,34 @@ pub fn bind_common_in_range(
ip_addr: IpAddr,
range: PortRange,
) -> io::Result<(u16, (UdpSocket, TcpListener))> {
let (start, end) = range;
let mut tries_left = end - start;
let mut rand_port = thread_rng().gen_range(start, end);
loop {
match bind_common(ip_addr, rand_port, false) {
Ok((sock, listener)) => {
break Result::Ok((sock.local_addr().unwrap().port(), (sock, listener)));
}
Err(err) => {
if tries_left == 0 {
return Err(err);
}
}
for port in range.0..range.1 {
if let Ok((sock, listener)) = bind_common(ip_addr, port, false) {
return Result::Ok((sock.local_addr().unwrap().port(), (sock, listener)));
}
rand_port += 1;
if rand_port == end {
rand_port = start;
}
tries_left -= 1;
}
return Err(io::Error::new(
io::ErrorKind::Other,
format!("No available TCP/UDP ports in {:?}", range),
));
}
pub fn bind_in_range(ip_addr: IpAddr, range: PortRange) -> io::Result<(u16, UdpSocket)> {
let sock = udp_socket(false)?;
let (start, end) = range;
let mut tries_left = end - start;
let mut rand_port = thread_rng().gen_range(start, end);
loop {
let addr = SocketAddr::new(ip_addr, rand_port);
for port in range.0..range.1 {
let addr = SocketAddr::new(ip_addr, port);
match sock.bind(&SockAddr::from(addr)) {
Ok(_) => {
let sock = sock.into_udp_socket();
break Result::Ok((sock.local_addr().unwrap().port(), sock));
}
Err(err) => {
if tries_left == 0 {
return Err(err);
}
}
if sock.bind(&SockAddr::from(addr)).is_ok() {
let sock = sock.into_udp_socket();
return Result::Ok((sock.local_addr().unwrap().port(), sock));
}
rand_port += 1;
if rand_port == end {
rand_port = start;
}
tries_left -= 1;
}
return Err(io::Error::new(
io::ErrorKind::Other,
format!("No available UDP ports in {:?}", range),
));
}
// binds many sockets to the same port in a range
@ -454,10 +434,10 @@ mod tests {
}
#[test]
#[should_panic]
fn test_bind_in_range_nil() {
let ip_addr = IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0));
let _ = bind_in_range(ip_addr, (2000, 2000));
bind_in_range(ip_addr, (2000, 2000)).unwrap_err();
bind_in_range(ip_addr, (2000, 1999)).unwrap_err();
}
#[test]