Add linux tun example

Cargo.toml

@@ -95,5 +95,9 @@ required-features = ["std", "phy-tap_interface", "proto-ipv4", "socket-raw", "so
 name = "dhcp_client"
 required-features = ["std", "phy-tap_interface", "proto-ipv4", "proto-dhcpv4", "socket-raw"]
 
+[[example]]
+name = "tunhttpclient"
+required-features = ["std", "phy-tun_interface", "proto-ipv4", "proto-ipv6", "socket-tcp"]
+
 [profile.release]
 debug = 2

examples/tunhttpclient.rs

@@ -0,0 +1,124 @@
+#[macro_use]
+extern crate log;
+extern crate env_logger;
+extern crate getopts;
+extern crate rand;
+extern crate url;
+extern crate smoltcp;
+
+mod utils;
+
+use smoltcp::phy::wait as phy_wait;
+use std::str::{self, FromStr};
+use std::collections::BTreeMap;
+use std::os::unix::io::AsRawFd;
+use url::Url;
+use smoltcp::wire::{Ipv4Address, Ipv6Address, IpAddress, IpCidr};
+use smoltcp::iface::{NeighborCache, InterfaceBuilder, Routes};
+use smoltcp::socket::{SocketSet, TcpSocket, TcpSocketBuffer};
+use smoltcp::time::Instant;
+use smoltcp::phy::TunInterface;
+
+fn main() {
+    /*
+        Usage:
+
+        Create tun1:
+
+        sudo ip tuntap add dev tun1 mode tun user `id -un`
+        sudo ip link set dev tun1 up
+        sudo ip addr add dev tun1 local 192.168.69.0 remote 192.168.69.1
+        sudo iptables -t filter -I FORWARD -i tun1 -o eth0 -j ACCEPT
+        sudo iptables -t filter -I FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
+        sudo iptables -t nat -I POSTROUTING -o eth0 -j MASQUERADE
+        sudo sysctl net.ipv4.ip_forward=1
+
+        ./tunhttpclient 172.217.28.238 http://google.com
+
+        You should get HTML from google (IP might change throughout history, ping to see)
+    */
+    utils::setup_logging("");
+
+    let (mut opts, mut free) = utils::create_options();
+    utils::add_middleware_options(&mut opts, &mut free);
+    free.push("ADDRESS");
+    free.push("URL");
+
+    let mut matches = utils::parse_options(&opts, free);
+    let device = TunInterface::new("tun1").unwrap();
+    let fd = device.as_raw_fd();
+    let device = utils::parse_middleware_options(&mut matches, device, /*loopback=*/false);
+    let address = IpAddress::from_str(&matches.free[0]).expect("invalid address format");
+    let url = Url::parse(&matches.free[1]).expect("invalid url format");
+
+    let tcp_rx_buffer = TcpSocketBuffer::new(vec![0; 1024]);
+    let tcp_tx_buffer = TcpSocketBuffer::new(vec![0; 1024]);
+    let tcp_socket = TcpSocket::new(tcp_rx_buffer, tcp_tx_buffer);
+
+    let ip_addrs = [IpCidr::new(IpAddress::v4(192, 168, 69, 1), 24),
+                    IpCidr::new(IpAddress::v6(0xfdaa, 0, 0, 0, 0, 0, 0, 1), 64),
+                    IpCidr::new(IpAddress::v6(0xfe80, 0, 0, 0, 0, 0, 0, 1), 64)];
+    let default_v4_gw = Ipv4Address::new(192, 168, 69, 100);
+    let default_v6_gw = Ipv6Address::new(0xfe80, 0, 0, 0, 0, 0, 0, 0x100);
+    let mut routes_storage = [None; 2];
+    let mut routes = Routes::new(&mut routes_storage[..]);
+    routes.add_default_ipv4_route(default_v4_gw).unwrap();
+    routes.add_default_ipv6_route(default_v6_gw).unwrap();
+    let mut iface = InterfaceBuilder::new(device)
+            .ip_addrs(ip_addrs)
+            .routes(routes)
+            .finalize();
+
+    let mut sockets = SocketSet::new(vec![]);
+    let tcp_handle = sockets.add(tcp_socket);
+
+    enum State { Connect, Request, Response };
+    let mut state = State::Connect;
+
+    loop {
+        let timestamp = Instant::now();
+        match iface.poll(&mut sockets, timestamp) {
+            Ok(_) => {},
+            Err(e) => {
+                debug!("poll error: {}",e);
+            }
+        }
+
+        {
+            let mut socket = sockets.get::<TcpSocket>(tcp_handle);
+
+            state = match state {
+                State::Connect if !socket.is_active() => {
+                    debug!("connecting");
+                    let local_port = 49152 + rand::random::<u16>() % 16384;
+                    socket.connect((address, url.port().unwrap_or(80)), local_port).unwrap();
+                    State::Request
+                }
+                State::Request if socket.may_send() => {
+                    debug!("sending request");
+                    let http_get = "GET ".to_owned() + url.path() + " HTTP/1.1\r\n";
+                    socket.send_slice(http_get.as_ref()).expect("cannot send");
+                    let http_host = "Host: ".to_owned() + url.host_str().unwrap() + "\r\n";
+                    socket.send_slice(http_host.as_ref()).expect("cannot send");
+                    socket.send_slice(b"Connection: close\r\n").expect("cannot send");
+                    socket.send_slice(b"\r\n").expect("cannot send");
+                    State::Response
+                }
+                State::Response if socket.can_recv() => {
+                    socket.recv(|data| {
+                        println!("{}", str::from_utf8(data).unwrap_or("(invalid utf8)"));
+                        (data.len(), ())
+                    }).unwrap();
+                    State::Response
+                }
+                State::Response if !socket.may_recv() => {
+                    debug!("received complete response");
+                    break
+                }
+                _ => state
+            }
+        }
+
+        phy_wait(fd, iface.poll_delay(&sockets, timestamp)).expect("wait error");
+    }
+}