Peer sharing in IP

src/interfaces/ip.rs

@@ -4,7 +4,9 @@ use alloc::vec;
 use alloc::vec::Vec;
 use core::ops::RangeInclusive;
 use core::time::Duration;
+use rayon::prelude::*;
 use std::net;
+use std::net::TcpStream;
 #[cfg(test)]
 use std::thread;
 
@@ -15,7 +17,10 @@ use crate::res::{IFError, IFResult};
 use crate::std::io::{Read, Write};
 use crate::std::println;
 
-const SOCKET_RANGE: RangeInclusive<i32> = 50000..=50010;
+const SOCKET_RANGE: RangeInclusive<u16> = 50000..=50010;
+
+/// The threshold for the number of peers below which we are desperate
+const PEER_THRESHOLD: usize = 70;
 
 /// Interface for interactions using tcp sockets
 pub struct IPInterface {
@@ -36,26 +41,26 @@ struct IPPackage {
 
 #[derive(Debug)]
 enum MessageType {
-    Service,
-    PeerRequest,
     Common,
+    PeerRequest,
+    PeersShared,
 }
 
 impl MessageType {
     fn from_u8(id: u8) -> IFResult<MessageType> {
         match id {
-            0 => Ok(MessageType::Service),
+            0 => Ok(MessageType::Common),
             1 => Ok(MessageType::PeerRequest),
-            2 => Ok(MessageType::Common),
+            2 => Ok(MessageType::PeersShared),
             _ => Err(IFError::General("Incorrect message type".to_string())),
         }
     }
 
     fn to_u8(&self) -> u8 {
         match self {
-            MessageType::Service => 0,
+            MessageType::Common => 0,
             MessageType::PeerRequest => 1,
-            MessageType::Common => 2,
+            MessageType::PeersShared => 2,
         }
     }
 }
@@ -70,13 +75,17 @@ impl Interface for IPInterface {
         match self.listener.accept() {
             Ok((stream, addr)) => {
                 println!("New client: {:?}", addr);
+                if !self.peers.contains(&addr.ip()) {
+                    self.peers.push(addr.ip());
+                }
                 self.connections.push(stream)
             }
             Err(_e) => return Err(IFError::General(String::from("No incoming connection"))),
         }
 
         println!("Hello from mainloop");
-        for mut connection in &self.connections {
+        let mut new_connections: Vec<TcpStream> = vec![];
+        for connection in &mut self.connections {
             let mut header: [u8; 6] = [0, 0, 0, 0, 0, 0];
             connection.read_exact(&mut header)?;
             let version = header[0];
@@ -87,14 +96,50 @@ impl Interface for IPInterface {
             let mut message: Vec<u8> = vec![];
             message_take.read_to_end(&mut message)?;
 
-            let package = IPPackage {
-                version,
-                package_type,
-                size,
-                message,
-            };
-            self.package_queue.push(package);
+            match package_type {
+                MessageType::PeerRequest => {
+                    let peers_to_share = if self.peers.len() < PEER_THRESHOLD {
+                        self.peers.clone()
+                    } else {
+                        self.peers.iter().skip(7).step_by(2).cloned().collect()
+                    };
+                    let message = serde_cbor::to_vec(&peers_to_share)?;
+                    IPInterface::send_package(
+                        connection,
+                        IPPackage {
+                            version,
+                            package_type,
+                            size: message.len() as u32,
+                            message,
+                        },
+                    )?;
+                }
+                MessageType::Common => {
+                    let package = IPPackage {
+                        version,
+                        package_type,
+                        size,
+                        message,
+                    };
+                    self.package_queue.push(package);
+                }
+                MessageType::PeersShared => {
+                    let peers: Vec<net::IpAddr> = serde_cbor::from_slice(message.as_slice())?;
+                    for peer in peers {
+                        if !self.peers.contains(&peer) {
+                            if let Some(conn) = IPInterface::new_connection(&peer)? {
+                                new_connections.push(conn)
+                            }
+                            self.peers.push(peer);
+                        }
+                    }
+                }
+            }
+        }
+        for conn in new_connections.iter_mut() {
+            self.initialize_connection(conn)?;
         }
+        self.connections.extend(new_connections);
 
         Ok(())
     }
@@ -160,7 +205,7 @@ impl Interface for IPInterface {
 }
 
 impl IPInterface {
-    pub fn new() -> IFResult<Self> {
+    pub fn new(peers: Vec<net::IpAddr>) -> IFResult<Self> {
         let listener = match create_tcp_listener() {
             Some(listener) => listener,
             None => {
@@ -172,11 +217,23 @@ impl IPInterface {
 
         listener.set_nonblocking(true)?;
 
+        let connections = peers
+            .par_iter()
+            .map(Self::new_connection)
+            .filter_map(|r| r.ok())
+            .filter_map(|r| r)
+            .map(|mut c| -> IFResult<TcpStream> {
+                Self::request_peers(&mut c)?;
+                Ok(c)
+            })
+            .filter_map(|r| r.ok())
+            .collect::<Vec<_>>();
+
         Ok(IPInterface {
             id: String::from("IP Interface"),
-            connections: vec![],
+            connections,
             listener,
-            peers: vec![],
+            peers,
             package_queue: vec![],
         })
     }
@@ -200,6 +257,55 @@ impl IPInterface {
 
         Ok(())
     }
+
+    fn initialize_connection(&self, conn: &mut TcpStream) -> IFResult<()> {
+        if self.peers.len() < PEER_THRESHOLD {
+            Self::request_peers(conn)?;
+        }
+        Ok(())
+    }
+
+    fn request_peers(conn: &mut TcpStream) -> IFResult<()> {
+        IPInterface::send_package(
+            conn,
+            IPPackage {
+                version: 0,
+                package_type: MessageType::PeerRequest,
+                size: 0,
+                message: vec![],
+            },
+        )?;
+        Ok(())
+    }
+
+    fn obtain_connection(&mut self, addr: &net::IpAddr) -> IFResult<()> {
+        if self
+            .connections
+            .iter()
+            .any(|con| con.peer_addr().is_ok() && &con.peer_addr().unwrap().ip() == addr)
+        {
+            return Ok(());
+        }
+        if let Some(conn) = Self::new_connection(addr)? {
+            self.connections.push(conn)
+        }
+        Ok(())
+    }
+
+    fn new_connection(addr: &net::IpAddr) -> IFResult<Option<TcpStream>> {
+        for port in SOCKET_RANGE {
+            match net::TcpStream::connect_timeout(
+                &net::SocketAddr::new(*addr, port as u16),
+                Duration::from_millis(500),
+            ) {
+                Ok(connection) => {
+                    return Ok(Some(connection));
+                }
+                Err(_) => continue,
+            };
+        }
+        Ok(None)
+    }
 }
 
 fn create_tcp_listener() -> Option<net::TcpListener> {
@@ -242,8 +348,8 @@ fn bytes_to_size(arr: [u8; 4]) -> u32 {
 fn test_creating_connection() -> IFResult<()> {
     let message = *b"Hello world from iron forest";
 
-    let mut interface1 = IPInterface::new()?;
-    let mut interface2 = IPInterface::new()?;
+    let mut interface1 = IPInterface::new(vec![])?;
+    let mut interface2 = IPInterface::new(vec![])?;
 
     let t1 = std::thread::spawn(move || {
         interface1