1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
use {
    crate::{HEADER_LENGTH, IP_ECHO_SERVER_RESPONSE_LENGTH},
    log::*,
    serde_derive::{Deserialize, Serialize},
    solana_sdk::deserialize_utils::default_on_eof,
    std::{
        io,
        net::{IpAddr, SocketAddr},
        time::Duration,
    },
    tokio::{
        io::{AsyncReadExt, AsyncWriteExt},
        net::{TcpListener, TcpStream},
        runtime::{self, Runtime},
        time::timeout,
    },
};

pub type IpEchoServer = Runtime;

pub const MAX_PORT_COUNT_PER_MESSAGE: usize = 4;

const IO_TIMEOUT: Duration = Duration::from_secs(5);

#[derive(Serialize, Deserialize, Default, Debug)]
pub(crate) struct IpEchoServerMessage {
    tcp_ports: [u16; MAX_PORT_COUNT_PER_MESSAGE], // Fixed size list of ports to avoid vec serde
    udp_ports: [u16; MAX_PORT_COUNT_PER_MESSAGE], // Fixed size list of ports to avoid vec serde
}

#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
pub struct IpEchoServerResponse {
    // Public IP address of request echoed back to the node.
    pub(crate) address: IpAddr,
    // Cluster shred-version of the node running the server.
    #[serde(deserialize_with = "default_on_eof")]
    pub(crate) shred_version: Option<u16>,
}

impl IpEchoServerMessage {
    pub fn new(tcp_ports: &[u16], udp_ports: &[u16]) -> Self {
        let mut msg = Self::default();
        assert!(tcp_ports.len() <= msg.tcp_ports.len());
        assert!(udp_ports.len() <= msg.udp_ports.len());

        msg.tcp_ports[..tcp_ports.len()].copy_from_slice(tcp_ports);
        msg.udp_ports[..udp_ports.len()].copy_from_slice(udp_ports);
        msg
    }
}

pub(crate) fn ip_echo_server_request_length() -> usize {
    const REQUEST_TERMINUS_LENGTH: usize = 1;
    HEADER_LENGTH
        + bincode::serialized_size(&IpEchoServerMessage::default()).unwrap() as usize
        + REQUEST_TERMINUS_LENGTH
}

async fn process_connection(
    mut socket: TcpStream,
    peer_addr: SocketAddr,
    shred_version: Option<u16>,
) -> io::Result<()> {
    info!("connection from {:?}", peer_addr);

    let mut data = vec![0u8; ip_echo_server_request_length()];

    let mut writer = {
        let (mut reader, writer) = socket.split();
        let _ = timeout(IO_TIMEOUT, reader.read_exact(&mut data)).await??;
        writer
    };

    let request_header: String = data[0..HEADER_LENGTH].iter().map(|b| *b as char).collect();
    if request_header != "\0\0\0\0" {
        // Explicitly check for HTTP GET/POST requests to more gracefully handle
        // the case where a user accidentally tried to use a gossip entrypoint in
        // place of a JSON RPC URL:
        if request_header == "GET " || request_header == "POST" {
            // Send HTTP error response
            timeout(
                IO_TIMEOUT,
                writer.write_all(b"HTTP/1.1 400 Bad Request\nContent-length: 0\n\n"),
            )
            .await??;
            return Ok(());
        }
        return Err(io::Error::new(
            io::ErrorKind::Other,
            format!("Bad request header: {}", request_header),
        ));
    }

    let msg =
        bincode::deserialize::<IpEchoServerMessage>(&data[HEADER_LENGTH..]).map_err(|err| {
            io::Error::new(
                io::ErrorKind::Other,
                format!("Failed to deserialize IpEchoServerMessage: {:?}", err),
            )
        })?;

    trace!("request: {:?}", msg);

    // Fire a datagram at each non-zero UDP port
    match std::net::UdpSocket::bind("0.0.0.0:0") {
        Ok(udp_socket) => {
            for udp_port in &msg.udp_ports {
                if *udp_port != 0 {
                    match udp_socket.send_to(&[0], SocketAddr::from((peer_addr.ip(), *udp_port))) {
                        Ok(_) => debug!("Successful send_to udp/{}", udp_port),
                        Err(err) => info!("Failed to send_to udp/{}: {}", udp_port, err),
                    }
                }
            }
        }
        Err(err) => {
            warn!("Failed to bind local udp socket: {}", err);
        }
    }

    // Try to connect to each non-zero TCP port
    for tcp_port in &msg.tcp_ports {
        if *tcp_port != 0 {
            debug!("Connecting to tcp/{}", tcp_port);

            let mut tcp_stream = timeout(
                IO_TIMEOUT,
                TcpStream::connect(&SocketAddr::new(peer_addr.ip(), *tcp_port)),
            )
            .await??;

            debug!("Connection established to tcp/{}", *tcp_port);
            let _ = tcp_stream.shutdown();
        }
    }
    let response = IpEchoServerResponse {
        address: peer_addr.ip(),
        shred_version,
    };
    // "\0\0\0\0" header is added to ensure a valid response will never
    // conflict with the first four bytes of a valid HTTP response.
    let mut bytes = vec![0u8; IP_ECHO_SERVER_RESPONSE_LENGTH];
    bincode::serialize_into(&mut bytes[HEADER_LENGTH..], &response).unwrap();
    trace!("response: {:?}", bytes);
    writer.write_all(&bytes).await
}

async fn run_echo_server(tcp_listener: std::net::TcpListener, shred_version: Option<u16>) {
    info!("bound to {:?}", tcp_listener.local_addr().unwrap());
    let tcp_listener =
        TcpListener::from_std(tcp_listener).expect("Failed to convert std::TcpListener");

    loop {
        match tcp_listener.accept().await {
            Ok((socket, peer_addr)) => {
                runtime::Handle::current().spawn(async move {
                    if let Err(err) = process_connection(socket, peer_addr, shred_version).await {
                        info!("session failed: {:?}", err);
                    }
                });
            }
            Err(err) => warn!("listener accept failed: {:?}", err),
        }
    }
}

/// Starts a simple TCP server on the given port that echos the IP address of any peer that
/// connects.  Used by |get_public_ip_addr|
pub fn ip_echo_server(
    tcp_listener: std::net::TcpListener,
    // Cluster shred-version of the node running the server.
    shred_version: Option<u16>,
) -> IpEchoServer {
    tcp_listener.set_nonblocking(true).unwrap();

    let runtime = Runtime::new().expect("Failed to create Runtime");
    runtime.spawn(run_echo_server(tcp_listener, shred_version));
    runtime
}