chore(release) temporary disable the MIPS musl target until new versions

of `libc` is released with `libc::sock_txtime`

.github/workflows/release.yml

@@ -26,9 +26,9 @@ jobs:
           - aarch64-unknown-linux-gnu
           - aarch64-unknown-linux-musl
           - mips-unknown-linux-gnu
-          - mips-unknown-linux-musl
+          #- mips-unknown-linux-musl # currently does not build due to libc::sock_txtime not found, need a newer release of libc
           - mipsel-unknown-linux-gnu
-          - mipsel-unknown-linux-musl
+          #- mipsel-unknown-linux-musl
 
     steps:
       - uses: actions/checkout@v3

README.md

@@ -35,7 +35,7 @@ Table of Contents
 
 # Latest release
 
-[v0.3.1](https://github.com/dndx/phantun/releases/tag/v0.3.1)
+[v0.4.2](https://github.com/dndx/phantun/releases/tag/v0.4.2)
 
 # Overview
 
@@ -59,6 +59,7 @@ Phantun is written in 100% safe Rust. It has been optimized extensively to scale
 systems and has no issue saturating all available CPU resources on a fast connection.
 See the [Performance](#performance) section for benchmarking results.
 
+![Phantun benchmark results](images/phantun-vs-udp2raw-benchmark-result.png)
 ![Traffic flow diagram](images/traffic-flow.png)
 
 # Usage
@@ -71,30 +72,32 @@ It is also assumed that **Phantun Client** listens for incoming UDP packets at
 `127.0.0.1:1234` (the `--local` option for client) and connects to Phantun Server at `10.0.0.1:4567`
 (the `--remote` option for client).
 
-Phantun creates TUN interface for both the Client and Server. For Client, Phantun assigns itself the IP address
-`192.168.200.2` by default and for Server, it assigns `192.168.201.2` by default. Therefore, your Kernel must have
-`net.ipv4.ip_forward` enabled and setup appropriate iptables rules for NAT between your physical
-NIC address and Phantun's TUN interface address.
+Phantun creates TUN interface for both the Client and Server. For **Client**, Phantun assigns itself the IP address
+`192.168.200.2` and `fcc8::2` by default.
+For **Server**, it assigns `192.168.201.2` and `fcc9::2` by default. Therefore, your Kernel must have
+IPv4/IPv6 forwarding enabled and setup appropriate iptables/nftables rules for NAT between your physical
+NIC address and Phantun's Tun interface address.
 
 You may customize the name of Tun interface created by Phantun and the assigned addresses. Please
 run the executable with `-h` options to see how to change them.
 
 Another way to help understand this network topology (please see the diagram above for an illustration of this topology):
 
-Phantun Client is like a machine with private IP address (`192.168.200.2`) behind a router.
+Phantun Client is like a machine with private IP address (`192.168.200.2`/`fcc8::2`) behind a router.
 In order for it to reach the Internet, you will need to SNAT the private IP address before it's traffic
 leaves the NIC.
 
-Phantun Server is like a server with private IP address (`192.168.201.2`) behind a router.
+Phantun Server is like a server with private IP address (`192.168.201.2`/`fcc9::2`) behind a router.
 In order to access it from the Internet, you need to `DNAT` it's listening port on the router
 and change the destination IP address to where the server is listening for incoming connections.
 
 In those cases, the machine/iptables running Phantun acts as the "router" that allows Phantun
 to communicate with outside using it's private IP addresses.
 
-As of Phantun v0.2.2, IPv6 support for UDP endpoints has been added, however Fake TCP IPv6 support
-has not been finished yet. To specify an IPv6 address, use the following format: `[::1]:1234` with
-the command line options.
+As of Phantun v0.4.1, IPv6 is fully supported for both TCP and UDP sides.
+To specify an IPv6 address, use the following format: `[::1]:1234` with
+the command line options. Resolving AAAA record is also supported. Please run the program
+with `-h` to see detailed options on how to control the IPv6 behavior.
 
 [Back to TOC](#table-of-contents)
 
@@ -102,6 +105,12 @@ the command line options.
 
 Edit `/etc/sysctl.conf`, add `net.ipv4.ip_forward=1` and run `sudo sysctl -p /etc/sysctl.conf`.
 
+<details>
+  <summary>IPv6 specific config</summary>
+
+  `net.ipv6.conf.all.forwarding=1` will need to be set as well.
+</details>
+
 [Back to TOC](#table-of-contents)
 
 ## 2. Add required firewall rules
@@ -127,12 +136,16 @@ table inet nat {
 }
 ```
 
+Note: The above rule uses `inet` as the table family type, so it is compatible with
+both IPv4 and IPv6 usage.
+
 [Back to TOC](#table-of-contents)
 
 #### Using iptables
 
 ```
 iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
+ip6tables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
 ```
 
 [Back to TOC](#table-of-contents)
@@ -149,10 +162,11 @@ actual TCP port number used by Phantun server
 #### Using nftables
 
 ```
-table ip nat {
+table inet nat {
     chain prerouting {
         type nat hook prerouting priority dstnat; policy accept;
-        iif eth0 tcp dport 4567 dnat to 192.168.201.2
+        iif eth0 tcp dport 4567 dnat ip to 192.168.201.2
+        iif eth0 tcp dport 4567 dnat ip6 to fcc9::2
     }
 }
 ```
@@ -163,6 +177,7 @@ table ip nat {
 
 ```
 iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 4567 -j DNAT --to-destination 192.168.201.2
+ip6tables -t nat -A PREROUTING -p tcp -i eth0 --dport 4567 -j DNAT --to-destination fcc9::2
 ```
 
 [Back to TOC](#table-of-contents)
@@ -201,6 +216,10 @@ Or use host name with `--remote`:
 RUST_LOG=info /usr/local/bin/phantun_server --local 4567 --remote example.com:1234
 ```
 
+Note: Server by default assigns both IPv4 and IPv6 private address to the Tun interface.
+If you do not wish to use IPv6, you can simply skip creating the IPv6 DNAT rule above and
+the presence of IPv6 address on the Tun interface should have no side effect to the server.
+
 [Back to TOC](#table-of-contents)
 
 ### Client
@@ -218,12 +237,22 @@ Or use host name with `--remote`:
 RUST_LOG=info /usr/local/bin/phantun_client --local 127.0.0.1:1234 --remote example.com:4567
 ```
 
+<details>
+  <summary>IPv6 specific config</summary>
+
+  ```
+  RUST_LOG=info /usr/local/bin/phantun_client --local 127.0.0.1:1234 --remote [fdxx::1234]:4567
+  ```
+
+  Domain name with AAAA record is also supported.
+</details>
+
 [Back to TOC](#table-of-contents)
 
 # MTU overhead
 
 Phantun aims to keep tunneling overhead to the minimum. The overhead compared to a plain UDP packet
-is the following:
+is the following (using IPv4 below as an example):
 
 **Standard UDP packet:** `20 byte IP header + 8 byte UDP header = 28 bytes`
 
@@ -247,18 +276,23 @@ For people who use Phantun to tunnel [WireGuard®](https://www.wireguard.com) UD
 out the correct MTU to use for your WireGuard interface.
 
 ```
-WireGuard MTU = Interface MTU - IP header (20 bytes) - TCP header (20 bytes) - WireGuard overhead (32 bytes)
+WireGuard MTU = Interface MTU - IPv4 header (20 bytes) - TCP header (20 bytes) - WireGuard overhead (32 bytes)
+```
+
+or
+
+```
+WireGuard MTU = Interface MTU - IPv6 header (40 bytes) - TCP header (20 bytes) - WireGuard overhead (32 bytes)
 ```
 
 For example, for a Ethernet interface with 1500 bytes MTU, the WireGuard interface MTU should be set as:
 
-```
-1500 - 20 - 20 - 32 = 1428 bytes
-```
+IPv4: `1500 - 20 - 20 - 32 = 1428 bytes`
+IPv6: `1500 - 40 - 20 - 32 = 1408 bytes`
 
 The resulted Phantun TCP data packet will be 1500 bytes which does not exceed the
 interface MTU of 1500. Please note it is strongly recommended to use the same interface
-MTU for both ends of a WireGuard tunnel, or unexected packet loss may occur and these issues are
+MTU for both ends of a WireGuard tunnel, or unexpected packet loss may occur and these issues are
 generally very hard to troubleshoot.
 
 [Back to TOC](#table-of-contents)
@@ -282,19 +316,23 @@ For users who wish to use `fake-tcp` library inside their own project, refer to
 Performance was tested on 2 AWS `t4g.xlarge` instances with 4 vCPUs and 5 Gb/s NIC over LAN. `nftables` was used to redirect
 UDP stream of `iperf3` to go through the Phantun/udp2raw tunnel between two test instances and MTU has been tuned to avoid fragmentation.
 
+Phantun `v0.3.2` and `udp2raw_arm_asm_aes` `20200818.0` was used. These were the latest release of both projects as of Apr 2022.
+
 Test command: `iperf3 -c <IP> -p <PORT> -R -u -l 1400 -b 1000m -t 30 -P 5`
 
-| Mode                                                          | Speed          | Overall CPU Usage        |
-|---------------------------------------------------------------|----------------|--------------------------|
-| Direct connection                                             | 3.35 Gbits/sec | 25% (1 core at 100%)     |
-| Phantun                                                       | 2.03 Gbits/sec | 95% (all cores utilized) |
-| udp2raw (cipher-mode=none auth-mode=none disable-anti-replay) | 876 Mbits/sec  | 50% (2 cores at 100%)    |
+| Mode                                                                            | Send Speed     | Receive Speed  | Overall CPU Usage                                   |
+|---------------------------------------------------------------------------------|----------------|----------------|-----------------------------------------------------|
+| Direct (1 stream)                                                               | 3.00 Gbits/sec | 2.37 Gbits/sec | 25% (1 core at 100%)                                |
+| Phantun (1 stream)                                                              | 1.30 Gbits/sec | 1.20 Gbits/sec | 60% (1 core at 100%, 3 cores at 50%)                |
+| udp2raw (`cipher-mode=none` `auth-mode=none` `disable-anti-replay`) (1 stream)  | 1.30 Gbits/sec | 715 Mbits/sec  | 40% (1 core at 100%, 1 core at 50%, 2 cores idling) |
+| Direct connection (5 streams)                                                   | 5.00 Gbits/sec | 3.64 Gbits/sec | 25% (1 core at 100%)                                |
+| Phantun (5 streams)                                                             | 5.00 Gbits/sec | 2.38 Gbits/sec | 95% (all cores utilized)                            |
+| udp2raw (`cipher-mode=none` `auth-mode=none` `disable-anti-replay`) (5 streams) | 5.00 Gbits/sec | 770 Mbits/sec  | 50% (2 cores at 100%)                               |
 
 [Back to TOC](#table-of-contents)
 
 # Future plans
 
-* IPv6 support for fake-tcp
 * Load balancing a single UDP stream into multiple TCP streams
 * Integration tests
 * Auto insertion/removal of required firewall rules
@@ -318,11 +356,11 @@ Here is a quick overview of comparison between those two to help you choose:
 | UDP over UDP obfuscation                         |       ❌       |         ✅         |
 | Multi-threaded                                   |       ✅       |         ❌         |
 | Throughput                                       |     Better    |        Good       |
-| L4 IP mode                                       | TUN interface | Raw sockets + BPF |
+| Layer 3 mode                                     | TUN interface | Raw sockets + BPF |
 | Tunneling MTU overhead                           |    12 bytes   |      44 bytes     |
 | Seprate TCP connections for each UDP connection  | Client/Server |    Server only    |
 | Anti-replay, encryption                          |       ❌       |         ✅         |
-| IPv6                                             |    UDP only    |         ✅         |
+| IPv6                                             |       ✅       |          ✅        |
 
 [Back to TOC](#table-of-contents)
 

fake-tcp/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fake-tcp"
-version = "0.3.1"
+version = "0.4.0"
 edition = "2021"
 authors = ["Datong Sun <dndx@idndx.com>"]
 license = "MIT OR Apache-2.0"
@@ -16,7 +16,7 @@ benchmark = []
 
 [dependencies]
 bytes = "1"
-pnet = "0.29"
+pnet = "0.30"
 tokio = { version = "1.14", features = ["full"] }
 rand = { version = "0.8", features = ["small_rng"] }
 log = "0.4"

fake-tcp/src/lib.rs

@@ -49,7 +49,7 @@ use pnet::packet::{tcp, Packet};
 use rand::prelude::*;
 use std::collections::{HashMap, HashSet};
 use std::fmt;
-use std::net::{Ipv4Addr, SocketAddrV4};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
 use std::sync::atomic::{AtomicU32, Ordering};
 use std::sync::{Arc, RwLock};
 use tokio::sync::broadcast;
@@ -65,12 +65,12 @@ const MAX_UNACKED_LEN: u32 = 128 * 1024 * 1024; // 128MB
 
 #[derive(Hash, Eq, PartialEq, Clone, Debug)]
 struct AddrTuple {
-    local_addr: SocketAddrV4,
-    remote_addr: SocketAddrV4,
+    local_addr: SocketAddr,
+    remote_addr: SocketAddr,
 }
 
 impl AddrTuple {
-    fn new(local_addr: SocketAddrV4, remote_addr: SocketAddrV4) -> AddrTuple {
+    fn new(local_addr: SocketAddr, remote_addr: SocketAddr) -> AddrTuple {
         AddrTuple {
             local_addr,
             remote_addr,
@@ -89,6 +89,7 @@ struct Shared {
 pub struct Stack {
     shared: Arc<Shared>,
     local_ip: Ipv4Addr,
+    local_ip6: Option<Ipv6Addr>,
     ready: mpsc::Receiver<Socket>,
 }
 
@@ -103,8 +104,8 @@ pub struct Socket {
     shared: Arc<Shared>,
     tun: Arc<Tun>,
     incoming: flume::Receiver<Bytes>,
-    local_addr: SocketAddrV4,
-    remote_addr: SocketAddrV4,
+    local_addr: SocketAddr,
+    remote_addr: SocketAddr,
     seq: AtomicU32,
     ack: AtomicU32,
     last_ack: AtomicU32,
@@ -122,8 +123,8 @@ impl Socket {
     fn new(
         shared: Arc<Shared>,
         tun: Arc<Tun>,
-        local_addr: SocketAddrV4,
-        remote_addr: SocketAddrV4,
+        local_addr: SocketAddr,
+        remote_addr: SocketAddr,
         ack: Option<u32>,
         state: State,
     ) -> (Socket, flume::Sender<Bytes>) {
@@ -188,7 +189,7 @@ impl Socket {
         match self.state {
             State::Established => {
                 self.incoming.recv_async().await.ok().and_then(|raw_buf| {
-                    let (_v4_packet, tcp_packet) = parse_ipv4_packet(&raw_buf);
+                    let (_v4_packet, tcp_packet) = parse_ip_packet(&raw_buf).unwrap();
 
                     if (tcp_packet.get_flags() & tcp::TcpFlags::RST) != 0 {
                         info!("Connection {} reset by peer", self);
@@ -233,7 +234,7 @@ impl Socket {
                     let res = time::timeout(TIMEOUT, self.incoming.recv_async()).await;
                     if let Ok(buf) = res {
                         let buf = buf.unwrap();
-                        let (_v4_packet, tcp_packet) = parse_ipv4_packet(&buf);
+                        let (_v4_packet, tcp_packet) = parse_ip_packet(&buf).unwrap();
 
                         if (tcp_packet.get_flags() & tcp::TcpFlags::RST) != 0 {
                             return;
@@ -277,7 +278,7 @@ impl Socket {
                     match time::timeout(TIMEOUT, self.incoming.recv_async()).await {
                         Ok(buf) => {
                             let buf = buf.unwrap();
-                            let (_v4_packet, tcp_packet) = parse_ipv4_packet(&buf);
+                            let (_v4_packet, tcp_packet) = parse_ip_packet(&buf).unwrap();
 
                             if (tcp_packet.get_flags() & tcp::TcpFlags::RST) != 0 {
                                 return None;
@@ -358,7 +359,7 @@ impl Stack {
     /// When more than one [`Tun`](tokio_tun::Tun) object is passed in, same amount
     /// of reader will be spawned later. This allows user to utilize the performance
     /// benefit of Multiqueue Tun support on machines with SMP.
-    pub fn new(tun: Vec<Tun>) -> Stack {
+    pub fn new(tun: Vec<Tun>, local_ip: Ipv4Addr, local_ip6: Option<Ipv6Addr>) -> Stack {
         let tun: Vec<Arc<Tun>> = tun.into_iter().map(Arc::new).collect();
         let (ready_tx, ready_rx) = mpsc::channel(MPSC_BUFFER_LEN);
         let (tuples_purge_tx, _tuples_purge_rx) = broadcast::channel(16);
@@ -369,7 +370,6 @@ impl Stack {
             ready: ready_tx,
             tuples_purge: tuples_purge_tx.clone(),
         });
-        let local_ip = tun[0].destination().unwrap();
 
         for t in tun {
             tokio::spawn(Stack::reader_task(
@@ -382,6 +382,7 @@ impl Stack {
         Stack {
             shared,
             local_ip,
+            local_ip6,
             ready: ready_rx,
         }
     }
@@ -398,10 +399,17 @@ impl Stack {
 
     /// Connects to the remote end. `None` returned means
     /// the connection attempt failed.
-    pub async fn connect(&mut self, addr: SocketAddrV4) -> Option<Socket> {
+    pub async fn connect(&mut self, addr: SocketAddr) -> Option<Socket> {
         let mut rng = SmallRng::from_entropy();
         let local_port: u16 = rng.gen_range(1024..65535);
-        let local_addr = SocketAddrV4::new(self.local_ip, local_port);
+        let local_addr = SocketAddr::new(
+            if addr.is_ipv4() {
+                IpAddr::V4(self.local_ip)
+            } else {
+                IpAddr::V6(self.local_ip6.expect("IPv6 local address undefined"))
+            },
+            local_port,
+        );
         let tuple = AddrTuple::new(local_addr, addr);
         let (mut sock, incoming) = Socket::new(
             self.shared.clone(),
@@ -437,90 +445,90 @@ impl Stack {
                     buf.truncate(size);
                     let buf = buf.freeze();
 
-                    if buf[0] >> 4 != 4 {
-                        // not an IPv4 packet
-                        continue;
-                    }
+                    match parse_ip_packet(&buf) {
+                        Some((ip_packet, tcp_packet)) => {
+                            let local_addr =
+                                SocketAddr::new(ip_packet.get_destination(), tcp_packet.get_destination());
+                            let remote_addr = SocketAddr::new(ip_packet.get_source(), tcp_packet.get_source());
 
-                    let (ip_packet, tcp_packet) = parse_ipv4_packet(&buf);
-                    let local_addr =
-                        SocketAddrV4::new(ip_packet.get_destination(), tcp_packet.get_destination());
-                    let remote_addr = SocketAddrV4::new(ip_packet.get_source(), tcp_packet.get_source());
+                            let tuple = AddrTuple::new(local_addr, remote_addr);
+                            if let Some(c) = tuples.get(&tuple) {
+                                if c.send_async(buf).await.is_err() {
+                                    trace!("Cache hit, but receiver already closed, dropping packet");
+                                }
 
-                    let tuple = AddrTuple::new(local_addr, remote_addr);
-                    if let Some(c) = tuples.get(&tuple) {
-                        if c.send_async(buf).await.is_err() {
-                            trace!("Cache hit, but receiver already closed, dropping packet");
+                                continue;
+
+                                // If not Ok, receiver has been closed and just fall through to the slow
+                                // path below
+                            } else {
+                                trace!("Cache miss, checking the shared tuples table for connection");
+                                let sender = {
+                                    let tuples = shared.tuples.read().unwrap();
+                                    tuples.get(&tuple).cloned()
+                                };
+
+                                if let Some(c) = sender {
+                                    trace!("Storing connection information into local tuples");
+                                    tuples.insert(tuple, c.clone());
+                                    c.send_async(buf).await.unwrap();
+                                    continue;
+                                }
+                            }
+
+                            if tcp_packet.get_flags() == tcp::TcpFlags::SYN
+                                && shared
+                                    .listening
+                                    .read()
+                                    .unwrap()
+                                    .contains(&tcp_packet.get_destination())
+                            {
+                                // SYN seen on listening socket
+                                if tcp_packet.get_sequence() == 0 {
+                                    let (sock, incoming) = Socket::new(
+                                        shared.clone(),
+                                        tun.clone(),
+                                        local_addr,
+                                        remote_addr,
+                                        Some(tcp_packet.get_sequence() + 1),
+                                        State::Idle,
+                                    );
+                                    assert!(shared
+                                        .tuples
+                                        .write()
+                                        .unwrap()
+                                        .insert(tuple, incoming)
+                                        .is_none());
+                                    tokio::spawn(sock.accept());
+                                } else {
+                                    trace!("Bad TCP SYN packet from {}, sending RST", remote_addr);
+                                    let buf = build_tcp_packet(
+                                        local_addr,
+                                        remote_addr,
+                                        0,
+                                        tcp_packet.get_sequence() + tcp_packet.payload().len() as u32 + 1, // +1 because of SYN flag set
+                                        tcp::TcpFlags::RST | tcp::TcpFlags::ACK,
+                                        None,
+                                    );
+                                    shared.tun[0].try_send(&buf).unwrap();
+                                }
+                            } else if (tcp_packet.get_flags() & tcp::TcpFlags::RST) == 0 {
+                                info!("Unknown TCP packet from {}, sending RST", remote_addr);
+                                let buf = build_tcp_packet(
+                                    local_addr,
+                                    remote_addr,
+                                    tcp_packet.get_acknowledgement(),
+                                    tcp_packet.get_sequence() + tcp_packet.payload().len() as u32,
+                                    tcp::TcpFlags::RST | tcp::TcpFlags::ACK,
+                                    None,
+                                );
+                                shared.tun[0].try_send(&buf).unwrap();
+                            }
                         }
-
-                        continue;
-
-                        // If not Ok, receiver has been closed and just fall through to the slow
-                        // path below
-
-                    } else {
-                        trace!("Cache miss, checking the shared tuples table for connection");
-                        let sender = {
-                            let tuples = shared.tuples.read().unwrap();
-                            tuples.get(&tuple).cloned()
-                        };
-
-                        if let Some(c) = sender {
-                            trace!("Storing connection information into local tuples");
-                            tuples.insert(tuple, c.clone());
-                            c.send_async(buf).await.unwrap();
+                        None => {
                             continue;
                         }
                     }
-
-                    if tcp_packet.get_flags() == tcp::TcpFlags::SYN
-                        && shared
-                            .listening
-                            .read()
-                            .unwrap()
-                            .contains(&tcp_packet.get_destination())
-                    {
-                        // SYN seen on listening socket
-                        if tcp_packet.get_sequence() == 0 {
-                            let (sock, incoming) = Socket::new(
-                                shared.clone(),
-                                tun.clone(),
-                                local_addr,
-                                remote_addr,
-                                Some(tcp_packet.get_sequence() + 1),
-                                State::Idle,
-                            );
-                            assert!(shared
-                                .tuples
-                                .write()
-                                .unwrap()
-                                .insert(tuple, incoming)
-                                .is_none());
-                            tokio::spawn(sock.accept());
-                        } else {
-                            trace!("Bad TCP SYN packet from {}, sending RST", remote_addr);
-                            let buf = build_tcp_packet(
-                                local_addr,
-                                remote_addr,
-                                0,
-                                tcp_packet.get_sequence() + tcp_packet.payload().len() as u32 + 1, // +1 because of SYN flag set
-                                tcp::TcpFlags::RST | tcp::TcpFlags::ACK,
-                                None,
-                            );
-                            shared.tun[0].try_send(&buf).unwrap();
-                        }
-                    } else if (tcp_packet.get_flags() & tcp::TcpFlags::RST) == 0 {
-                        info!("Unknown TCP packet from {}, sending RST", remote_addr);
-                        let buf = build_tcp_packet(
-                            local_addr,
-                            remote_addr,
-                            tcp_packet.get_acknowledgement(),
-                            tcp_packet.get_sequence() + tcp_packet.payload().len() as u32,
-                            tcp::TcpFlags::RST | tcp::TcpFlags::ACK,
-                            None,
-                        );
-                        shared.tun[0].try_send(&buf).unwrap();
-                    }
                 },
                 tuple = tuples_purge.recv() => {
                     let tuple = tuple.unwrap();

fake-tcp/src/packet.rs

@@ -1,45 +1,85 @@
 use bytes::{Bytes, BytesMut};
 use internet_checksum::Checksum;
 use pnet::packet::Packet;
-use pnet::packet::{ip, ipv4, tcp};
+use pnet::packet::{ip, ipv4, ipv6, tcp};
 use std::convert::TryInto;
-use std::net::SocketAddrV4;
+use std::net::{IpAddr, SocketAddr};
 
 const IPV4_HEADER_LEN: usize = 20;
+const IPV6_HEADER_LEN: usize = 40;
 const TCP_HEADER_LEN: usize = 20;
 pub const MAX_PACKET_LEN: usize = 1500;
 
+pub enum IPPacket<'p> {
+    V4(ipv4::Ipv4Packet<'p>),
+    V6(ipv6::Ipv6Packet<'p>),
+}
+
+impl<'a> IPPacket<'a> {
+    pub fn get_source(&self) -> IpAddr {
+        match self {
+            IPPacket::V4(p) => IpAddr::V4(p.get_source()),
+            IPPacket::V6(p) => IpAddr::V6(p.get_source()),
+        }
+    }
+
+    pub fn get_destination(&self) -> IpAddr {
+        match self {
+            IPPacket::V4(p) => IpAddr::V4(p.get_destination()),
+            IPPacket::V6(p) => IpAddr::V6(p.get_destination()),
+        }
+    }
+}
+
 pub fn build_tcp_packet(
-    local_addr: SocketAddrV4,
-    remote_addr: SocketAddrV4,
+    local_addr: SocketAddr,
+    remote_addr: SocketAddr,
     seq: u32,
     ack: u32,
     flags: u16,
     payload: Option<&[u8]>,
 ) -> Bytes {
+    let ip_header_len = match local_addr {
+        SocketAddr::V4(_) => IPV4_HEADER_LEN,
+        SocketAddr::V6(_) => IPV6_HEADER_LEN,
+    };
     let wscale = (flags & tcp::TcpFlags::SYN) != 0;
     let tcp_header_len = TCP_HEADER_LEN + if wscale { 4 } else { 0 }; // nop + wscale
     let tcp_total_len = tcp_header_len + payload.map_or(0, |payload| payload.len());
-    let total_len = IPV4_HEADER_LEN + tcp_total_len;
+    let total_len = ip_header_len + tcp_total_len;
     let mut buf = BytesMut::with_capacity(total_len);
     buf.resize(total_len, 0);
 
-    let mut v4_buf = buf.split_to(IPV4_HEADER_LEN);
+    let mut ip_buf = buf.split_to(ip_header_len);
     let mut tcp_buf = buf.split_to(tcp_total_len);
     assert_eq!(0, buf.len());
 
-    let mut v4 = ipv4::MutableIpv4Packet::new(&mut v4_buf).unwrap();
-    v4.set_version(4);
-    v4.set_header_length(IPV4_HEADER_LEN as u8 / 4);
-    v4.set_next_level_protocol(ip::IpNextHeaderProtocols::Tcp);
-    v4.set_ttl(64);
-    v4.set_source(*local_addr.ip());
-    v4.set_destination(*remote_addr.ip());
-    v4.set_total_length(total_len.try_into().unwrap());
-    v4.set_flags(ipv4::Ipv4Flags::DontFragment);
-    let mut cksm = Checksum::new();
-    cksm.add_bytes(v4.packet());
-    v4.set_checksum(u16::from_be_bytes(cksm.checksum()));
+    match (local_addr, remote_addr) {
+        (SocketAddr::V4(local), SocketAddr::V4(remote)) => {
+            let mut v4 = ipv4::MutableIpv4Packet::new(&mut ip_buf).unwrap();
+            v4.set_version(4);
+            v4.set_header_length(IPV4_HEADER_LEN as u8 / 4);
+            v4.set_next_level_protocol(ip::IpNextHeaderProtocols::Tcp);
+            v4.set_ttl(64);
+            v4.set_source(*local.ip());
+            v4.set_destination(*remote.ip());
+            v4.set_total_length(total_len.try_into().unwrap());
+            v4.set_flags(ipv4::Ipv4Flags::DontFragment);
+            let mut cksm = Checksum::new();
+            cksm.add_bytes(v4.packet());
+            v4.set_checksum(u16::from_be_bytes(cksm.checksum()));
+        }
+        (SocketAddr::V6(local), SocketAddr::V6(remote)) => {
+            let mut v6 = ipv6::MutableIpv6Packet::new(&mut ip_buf).unwrap();
+            v6.set_version(6);
+            v6.set_payload_length(tcp_total_len.try_into().unwrap());
+            v6.set_next_header(ip::IpNextHeaderProtocols::Tcp);
+            v6.set_hop_limit(64);
+            v6.set_source(*local.ip());
+            v6.set_destination(*remote.ip());
+        }
+        _ => unreachable!(),
+    };
 
     let mut tcp = tcp::MutableTcpPacket::new(&mut tcp_buf).unwrap();
     tcp.set_window(0xffff);
@@ -59,24 +99,55 @@ pub fn build_tcp_packet(
     }
 
     let mut cksm = Checksum::new();
-    cksm.add_bytes(&local_addr.ip().octets());
-    cksm.add_bytes(&remote_addr.ip().octets());
     let ip::IpNextHeaderProtocol(tcp_protocol) = ip::IpNextHeaderProtocols::Tcp;
-    let mut pseudo = [0u8, tcp_protocol, 0, 0];
-    pseudo[2..].copy_from_slice(&(tcp_total_len as u16).to_be_bytes());
-    cksm.add_bytes(&pseudo);
+
+    match (local_addr, remote_addr) {
+        (SocketAddr::V4(local), SocketAddr::V4(remote)) => {
+            cksm.add_bytes(&local.ip().octets());
+            cksm.add_bytes(&remote.ip().octets());
+
+            let mut pseudo = [0u8, tcp_protocol, 0, 0];
+            pseudo[2..].copy_from_slice(&(tcp_total_len as u16).to_be_bytes());
+            cksm.add_bytes(&pseudo);
+        }
+        (SocketAddr::V6(local), SocketAddr::V6(remote)) => {
+            cksm.add_bytes(&local.ip().octets());
+            cksm.add_bytes(&remote.ip().octets());
+
+            let mut pseudo = [0u8, 0, 0, 0, 0, 0, 0, tcp_protocol];
+            pseudo[0..4].copy_from_slice(&(tcp_total_len as u32).to_be_bytes());
+            cksm.add_bytes(&pseudo);
+        }
+        _ => unreachable!(),
+    };
+
     cksm.add_bytes(tcp.packet());
     tcp.set_checksum(u16::from_be_bytes(cksm.checksum()));
 
-    v4_buf.unsplit(tcp_buf);
-    v4_buf.freeze()
+    ip_buf.unsplit(tcp_buf);
+    ip_buf.freeze()
 }
 
-pub fn parse_ipv4_packet(buf: &Bytes) -> (ipv4::Ipv4Packet, tcp::TcpPacket) {
-    let v4 = ipv4::Ipv4Packet::new(buf).unwrap();
-    let tcp = tcp::TcpPacket::new(&buf[IPV4_HEADER_LEN..]).unwrap();
+pub fn parse_ip_packet(buf: &Bytes) -> Option<(IPPacket, tcp::TcpPacket)> {
+    if buf[0] >> 4 == 4 {
+        let v4 = ipv4::Ipv4Packet::new(buf).unwrap();
+        if v4.get_next_level_protocol() != ip::IpNextHeaderProtocols::Tcp {
+            return None;
+        }
 
-    (v4, tcp)
+        let tcp = tcp::TcpPacket::new(&buf[IPV4_HEADER_LEN..]).unwrap();
+        Some((IPPacket::V4(v4), tcp))
+    } else if buf[0] >> 4 == 6 {
+        let v6 = ipv6::Ipv6Packet::new(buf).unwrap();
+        if v6.get_next_header() != ip::IpNextHeaderProtocols::Tcp {
+            return None;
+        }
+
+        let tcp = tcp::TcpPacket::new(&buf[IPV6_HEADER_LEN..]).unwrap();
+        Some((IPPacket::V6(v6), tcp))
+    } else {
+        None
+    }
 }
 
 #[cfg(all(test, feature = "benchmark"))]

phantun/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "phantun"
-version = "0.3.2"
+version = "0.5.0"
 edition = "2021"
 authors = ["Datong Sun <dndx@idndx.com>"]
 license = "MIT OR Apache-2.0"
@@ -13,10 +13,12 @@ Layer 3 & Layer 4 (NAPT) firewalls/NATs.
 [dependencies]
 clap = { version = "3.0", features = ["cargo"] }
 socket2 = { version = "0.4", features = ["all"] }
-fake-tcp = { path = "../fake-tcp", version = "0.3" }
+fake-tcp = { path = "../fake-tcp", version = "0.4" }
 tokio = { version = "1.14", features = ["full"] }
 tokio-util = "0.7"
 log = "0.4"
 pretty_env_logger = "0.4"
 tokio-tun = "0.5"
 num_cpus = "1.13"
+neli = "0.6"
+nix = "0.24"

phantun/src/bin/client.rs

@@ -2,8 +2,10 @@ use clap::{crate_version, Arg, Command};
 use fake_tcp::packet::MAX_PACKET_LEN;
 use fake_tcp::{Socket, Stack};
 use log::{debug, error, info};
-use phantun::utils::new_udp_reuseport;
+use phantun::utils::{assign_ipv6_address, new_udp_reuseport};
 use std::collections::HashMap;
+use std::fs;
+use std::io;
 use std::net::{Ipv4Addr, SocketAddr};
 use std::sync::Arc;
 use tokio::sync::{Notify, RwLock};
@@ -14,7 +16,7 @@ use tokio_util::sync::CancellationToken;
 use phantun::UDP_TTL;
 
 #[tokio::main]
-async fn main() {
+async fn main() -> io::Result<()> {
     pretty_env_logger::init();
 
     let matches = Command::new("Phantun Client")
@@ -35,7 +37,7 @@ async fn main() {
                 .long("remote")
                 .required(true)
                 .value_name("IP or HOST NAME:PORT")
-                .help("Sets the address or host name and port where Phantun Client connects to Phantun Server")
+                .help("Sets the address or host name and port where Phantun Client connects to Phantun Server, IPv6 address need to be specified as: \"[IPv6]:PORT\"")
                 .takes_value(true),
         )
         .arg(
@@ -52,7 +54,7 @@ async fn main() {
                 .long("tun-local")
                 .required(false)
                 .value_name("IP")
-                .help("Sets the Tun interface local address (O/S's end)")
+                .help("Sets the Tun interface IPv4 local address (O/S's end)")
                 .default_value("192.168.200.1")
                 .takes_value(true),
         )
@@ -61,12 +63,52 @@ async fn main() {
                 .long("tun-peer")
                 .required(false)
                 .value_name("IP")
-                .help("Sets the Tun interface destination (peer) address (Phantun Client's end). \
+                .help("Sets the Tun interface IPv4 destination (peer) address (Phantun Client's end). \
                        You will need to setup SNAT/MASQUERADE rules on your Internet facing interface \
                        in order for Phantun Client to connect to Phantun Server")
                 .default_value("192.168.200.2")
                 .takes_value(true),
         )
+        .arg(
+            Arg::new("ipv4_only")
+                .long("ipv4-only")
+                .short('4')
+                .required(false)
+                .help("Only use IPv4 address when connecting to remote")
+                .takes_value(false)
+                .conflicts_with_all(&["tun_local6", "tun_peer6"]),
+        )
+        .arg(
+            Arg::new("tun_local6")
+                .long("tun-local6")
+                .required(false)
+                .value_name("IP")
+                .help("Sets the Tun interface IPv6 local address (O/S's end)")
+                .default_value("fcc8::1")
+                .takes_value(true),
+        )
+        .arg(
+            Arg::new("tun_peer6")
+                .long("tun-peer6")
+                .required(false)
+                .value_name("IP")
+                .help("Sets the Tun interface IPv6 destination (peer) address (Phantun Client's end). \
+                       You will need to setup SNAT/MASQUERADE rules on your Internet facing interface \
+                       in order for Phantun Client to connect to Phantun Server")
+                .default_value("fcc8::2")
+                .takes_value(true),
+        )
+        .arg(
+            Arg::new("handshake_packet")
+                .long("handshake-packet")
+                .required(false)
+                .value_name("PATH")
+                .help("Specify a file, which, after TCP handshake, its content will be sent as the \
+                      first data packet to the server.\n\
+                      Note: ensure this file's size does not exceed the MTU of the outgoing interface. \
+                      The content is always sent out in a single packet and will not be further segmented")
+                .takes_value(true),
+        )
         .get_matches();
 
     let local_addr: SocketAddr = matches
@@ -75,16 +117,13 @@ async fn main() {
         .parse()
         .expect("bad local address");
 
+    let ipv4_only = matches.is_present("ipv4_only");
+
     let remote_addr = tokio::net::lookup_host(matches.value_of("remote").unwrap())
         .await
         .expect("bad remote address or host")
-        .find(|addr| addr.is_ipv4())
-        .expect("unable to resolve remote host name or no valid A record was returned");
-    let remote_addr = if let SocketAddr::V4(addr) = remote_addr {
-        addr
-    } else {
-        unreachable!();
-    };
+        .find(|addr| !ipv4_only || addr.is_ipv4())
+        .expect("unable to resolve remote host name");
     info!("Remote address is: {}", remote_addr);
 
     let tun_local: Ipv4Addr = matches
@@ -98,11 +137,30 @@ async fn main() {
         .parse()
         .expect("bad peer address for Tun interface");
 
+    let (tun_local6, tun_peer6) = if ipv4_only {
+        (None, None)
+    } else {
+        (
+            matches
+                .value_of("tun_local6")
+                .map(|v| v.parse().expect("bad local address for Tun interface")),
+            matches
+                .value_of("tun_peer6")
+                .map(|v| v.parse().expect("bad peer address for Tun interface")),
+        )
+    };
+
+    let tun_name = matches.value_of("tun").unwrap();
+    let handshake_packet: Option<Vec<u8>> = matches
+        .value_of("handshake_packet")
+        .map(fs::read)
+        .transpose()?;
+
     let num_cpus = num_cpus::get();
     info!("{} cores available", num_cpus);
 
     let tun = TunBuilder::new()
-        .name(matches.value_of("tun").unwrap()) // if name is empty, then it is set by kernel.
+        .name(tun_name) // if name is empty, then it is set by kernel.
         .tap(false) // false (default): TUN, true: TAP.
         .packet_info(false) // false: IFF_NO_PI, default is true.
         .up() // or set it up manually using `sudo ip link set <tun-name> up`.
@@ -111,130 +169,143 @@ async fn main() {
         .try_build_mq(num_cpus)
         .unwrap();
 
+    if remote_addr.is_ipv6() {
+        assign_ipv6_address(tun[0].name(), tun_local6.unwrap(), tun_peer6.unwrap());
+    }
+
     info!("Created TUN device {}", tun[0].name());
 
     let udp_sock = Arc::new(new_udp_reuseport(local_addr));
     let connections = Arc::new(RwLock::new(HashMap::<SocketAddr, Arc<Socket>>::new()));
 
-    let mut stack = Stack::new(tun);
+    let mut stack = Stack::new(tun, tun_peer, tun_peer6);
 
     let main_loop = tokio::spawn(async move {
         let mut buf_r = [0u8; MAX_PACKET_LEN];
 
         loop {
-            tokio::select! {
-                Ok((size, addr)) = udp_sock.recv_from(&mut buf_r) => {
-                    // seen UDP packet to listening socket, this means:
-                    // 1. It is a new UDP connection, or
-                    // 2. It is some extra packets not filtered by more specific
-                    //    connected UDP socket yet
-                    if let Some(sock) = connections.read().await.get(&addr) {
-                        sock.send(&buf_r[..size]).await;
-                        continue;
-                    }
+            let (size, addr) = udp_sock.recv_from(&mut buf_r).await?;
+            // seen UDP packet to listening socket, this means:
+            // 1. It is a new UDP connection, or
+            // 2. It is some extra packets not filtered by more specific
+            //    connected UDP socket yet
+            if let Some(sock) = connections.read().await.get(&addr) {
+                sock.send(&buf_r[..size]).await;
+                continue;
+            }
 
-                    info!("New UDP client from {}", addr);
-                    let sock = stack.connect(remote_addr).await;
-                    if sock.is_none() {
-                        error!("Unable to connect to remote {}", remote_addr);
-                        continue;
-                    }
+            info!("New UDP client from {}", addr);
+            let sock = stack.connect(remote_addr).await;
+            if sock.is_none() {
+                error!("Unable to connect to remote {}", remote_addr);
+                continue;
+            }
 
-                    let sock = Arc::new(sock.unwrap());
-                    // send first packet
-                    let res = sock.send(&buf_r[..size]).await;
-                    if res.is_none() {
-                        continue;
-                    }
+            let sock = Arc::new(sock.unwrap());
+            if let Some(ref p) = handshake_packet {
+                if sock.send(p).await.is_none() {
+                    error!("Failed to send handshake packet to remote, closing connection.");
+                    continue;
+                }
 
-                    assert!(connections.write().await.insert(addr, sock.clone()).is_none());
-                    debug!("inserted fake TCP socket into connection table");
+                debug!("Sent handshake packet to: {}", sock);
+            }
 
-                    // spawn "fastpath" UDP socket and task, this will offload main task
-                    // from forwarding UDP packets
+            // send first packet
+            if sock.send(&buf_r[..size]).await.is_none() {
+                continue;
+            }
 
-                    let packet_received = Arc::new(Notify::new());
-                    let quit = CancellationToken::new();
+            assert!(connections
+                .write()
+                .await
+                .insert(addr, sock.clone())
+                .is_none());
+            debug!("inserted fake TCP socket into connection table");
 
-                    for i in 0..num_cpus {
-                        let sock = sock.clone();
-                        let quit = quit.clone();
-                        let packet_received = packet_received.clone();
+            // spawn "fastpath" UDP socket and task, this will offload main task
+            // from forwarding UDP packets
 
-                        tokio::spawn(async move {
-                            let mut buf_udp = [0u8; MAX_PACKET_LEN];
-                            let mut buf_tcp = [0u8; MAX_PACKET_LEN];
-                            let udp_sock = new_udp_reuseport(local_addr);
-                            udp_sock.connect(addr).await.unwrap();
+            let packet_received = Arc::new(Notify::new());
+            let quit = CancellationToken::new();
 
-                            loop {
-                                tokio::select! {
-                                    Ok(size) = udp_sock.recv(&mut buf_udp) => {
-                                        if sock.send(&buf_udp[..size]).await.is_none() {
-                                            debug!("removed fake TCP socket from connections table");
-                                            quit.cancel();
-                                            return;
-                                        }
+            for i in 0..num_cpus {
+                let sock = sock.clone();
+                let quit = quit.clone();
+                let packet_received = packet_received.clone();
 
-                                        packet_received.notify_one();
-                                    },
-                                    res = sock.recv(&mut buf_tcp) => {
-                                        match res {
-                                            Some(size) => {
-                                                if size > 0 {
-                                                    if let Err(e) = udp_sock.send(&buf_tcp[..size]).await {
-                                                        error!("Unable to send UDP packet to {}: {}, closing connection", e, addr);
-                                                        quit.cancel();
-                                                        return;
-                                                    }
-                                                }
-                                            },
-                                            None => {
-                                                debug!("removed fake TCP socket from connections table");
-                                                quit.cancel();
-                                                return;
-                                            },
-                                        }
+                tokio::spawn(async move {
+                    let mut buf_udp = [0u8; MAX_PACKET_LEN];
+                    let mut buf_tcp = [0u8; MAX_PACKET_LEN];
+                    let udp_sock = new_udp_reuseport(local_addr);
+                    udp_sock.connect(addr).await.unwrap();
 
-                                        packet_received.notify_one();
-                                    },
-                                    _ = quit.cancelled() => {
-                                        debug!("worker {} terminated", i);
-                                        return;
-                                    },
-                                };
-                            }
-                        });
-                    }
-
-                    let connections = connections.clone();
-                    tokio::spawn(async move {
-                        loop {
-                            let read_timeout = time::sleep(UDP_TTL);
-                            let packet_received_fut = packet_received.notified();
-
-                            tokio::select! {
-                                _ = read_timeout => {
-                                    info!("No traffic seen in the last {:?}, closing connection", UDP_TTL);
-                                    connections.write().await.remove(&addr);
+                    loop {
+                        tokio::select! {
+                            Ok(size) = udp_sock.recv(&mut buf_udp) => {
+                                if sock.send(&buf_udp[..size]).await.is_none() {
                                     debug!("removed fake TCP socket from connections table");
-
                                     quit.cancel();
                                     return;
-                                },
-                                _ = quit.cancelled() => {
-                                    connections.write().await.remove(&addr);
-                                    debug!("removed fake TCP socket from connections table");
-                                    return;
-                                },
-                                _ = packet_received_fut => {},
-                            }
-                        }
-                    });
-                },
+                                }
+
+                                packet_received.notify_one();
+                            },
+                            res = sock.recv(&mut buf_tcp) => {
+                                match res {
+                                    Some(size) => {
+                                        if size > 0 {
+                                            if let Err(e) = udp_sock.send(&buf_tcp[..size]).await {
+                                                error!("Unable to send UDP packet to {}: {}, closing connection", e, addr);
+                                                quit.cancel();
+                                                return;
+                                            }
+                                        }
+                                    },
+                                    None => {
+                                        debug!("removed fake TCP socket from connections table");
+                                        quit.cancel();
+                                        return;
+                                    },
+                                }
+
+                                packet_received.notify_one();
+                            },
+                            _ = quit.cancelled() => {
+                                debug!("worker {} terminated", i);
+                                return;
+                            },
+                        };
+                    }
+                });
             }
+
+            let connections = connections.clone();
+            tokio::spawn(async move {
+                loop {
+                    let read_timeout = time::sleep(UDP_TTL);
+                    let packet_received_fut = packet_received.notified();
+
+                    tokio::select! {
+                        _ = read_timeout => {
+                            info!("No traffic seen in the last {:?}, closing connection", UDP_TTL);
+                            connections.write().await.remove(&addr);
+                            debug!("removed fake TCP socket from connections table");
+
+                            quit.cancel();
+                            return;
+                        },
+                        _ = quit.cancelled() => {
+                            connections.write().await.remove(&addr);
+                            debug!("removed fake TCP socket from connections table");
+                            return;
+                        },
+                        _ = packet_received_fut => {},
+                    }
+                }
+            });
         }
     });
 
-    tokio::join!(main_loop).0.unwrap();
+    tokio::join!(main_loop).0.unwrap()
 }

phantun/src/bin/server.rs

@@ -2,7 +2,9 @@ use clap::{crate_version, Arg, Command};
 use fake_tcp::packet::MAX_PACKET_LEN;
 use fake_tcp::Stack;
 use log::{debug, error, info};
-use phantun::utils::new_udp_reuseport;
+use phantun::utils::{assign_ipv6_address, new_udp_reuseport};
+use std::fs;
+use std::io;
 use std::net::Ipv4Addr;
 use std::sync::Arc;
 use tokio::net::UdpSocket;
@@ -14,7 +16,7 @@ use tokio_util::sync::CancellationToken;
 use phantun::UDP_TTL;
 
 #[tokio::main]
-async fn main() {
+async fn main() -> io::Result<()> {
     pretty_env_logger::init();
 
     let matches = Command::new("Phantun Server")
@@ -67,6 +69,46 @@ async fn main() {
                 .default_value("192.168.201.2")
                 .takes_value(true),
         )
+        .arg(
+            Arg::new("ipv4_only")
+                .long("ipv4-only")
+                .short('4')
+                .required(false)
+                .help("Do not assign IPv6 addresses to Tun interface")
+                .takes_value(false)
+                .conflicts_with_all(&["tun_local6", "tun_peer6"]),
+        )
+        .arg(
+            Arg::new("tun_local6")
+                .long("tun-local6")
+                .required(false)
+                .value_name("IP")
+                .help("Sets the Tun interface IPv6 local address (O/S's end)")
+                .default_value("fcc9::1")
+                .takes_value(true),
+        )
+        .arg(
+            Arg::new("tun_peer6")
+                .long("tun-peer6")
+                .required(false)
+                .value_name("IP")
+                .help("Sets the Tun interface IPv6 destination (peer) address (Phantun Client's end). \
+                       You will need to setup SNAT/MASQUERADE rules on your Internet facing interface \
+                       in order for Phantun Client to connect to Phantun Server")
+                .default_value("fcc9::2")
+                .takes_value(true),
+        )
+        .arg(
+            Arg::new("handshake_packet")
+                .long("handshake-packet")
+                .required(false)
+                .value_name("PATH")
+                .help("Specify a file, which, after TCP handshake, its content will be sent as the \
+                      first data packet to the client.\n\
+                      Note: ensure this file's size does not exceed the MTU of the outgoing interface. \
+                      The content is always sent out in a single packet and will not be further segmented")
+                .takes_value(true),
+        )
         .get_matches();
 
     let local_port: u16 = matches
@@ -93,11 +135,30 @@ async fn main() {
         .parse()
         .expect("bad peer address for Tun interface");
 
+    let (tun_local6, tun_peer6) = if matches.is_present("ipv4_only") {
+        (None, None)
+    } else {
+        (
+            matches
+                .value_of("tun_local6")
+                .map(|v| v.parse().expect("bad local address for Tun interface")),
+            matches
+                .value_of("tun_peer6")
+                .map(|v| v.parse().expect("bad peer address for Tun interface")),
+        )
+    };
+
+    let tun_name = matches.value_of("tun").unwrap();
+    let handshake_packet: Option<Vec<u8>> = matches
+        .value_of("handshake_packet")
+        .map(fs::read)
+        .transpose()?;
+
     let num_cpus = num_cpus::get();
     info!("{} cores available", num_cpus);
 
     let tun = TunBuilder::new()
-        .name(matches.value_of("tun").unwrap()) // if name is empty, then it is set by kernel.
+        .name(tun_name) // if name is empty, then it is set by kernel.
         .tap(false) // false (default): TUN, true: TAP.
         .packet_info(false) // false: IFF_NO_PI, default is true.
         .up() // or set it up manually using `sudo ip link set <tun-name> up`.
@@ -106,10 +167,14 @@ async fn main() {
         .try_build_mq(num_cpus)
         .unwrap();
 
+    if let (Some(tun_local6), Some(tun_peer6)) = (tun_local6, tun_peer6) {
+        assign_ipv6_address(tun[0].name(), tun_local6, tun_peer6);
+    }
+
     info!("Created TUN device {}", tun[0].name());
 
     //thread::sleep(time::Duration::from_secs(5));
-    let mut stack = Stack::new(tun);
+    let mut stack = Stack::new(tun, tun_local, tun_local6);
     stack.listen(local_port);
     info!("Listening on {}", local_port);
 
@@ -120,6 +185,14 @@ async fn main() {
         loop {
             let sock = Arc::new(stack.accept().await);
             info!("New connection: {}", sock);
+            if let Some(ref p) = handshake_packet {
+                if sock.send(p).await.is_none() {
+                    error!("Failed to send handshake packet to remote, closing connection.");
+                    continue;
+                }
+
+                debug!("Sent handshake packet to: {}", sock);
+            }
 
             let packet_received = Arc::new(Notify::new());
             let quit = CancellationToken::new();
@@ -128,9 +201,8 @@ async fn main() {
             } else {
                 "[::]:0"
             })
-            .await
-            .unwrap();
-            let local_addr = udp_sock.local_addr().unwrap();
+            .await?;
+            let local_addr = udp_sock.local_addr()?;
             drop(udp_sock);
 
             for i in 0..num_cpus {
@@ -199,5 +271,5 @@ async fn main() {
         }
     });
 
-    tokio::join!(main_loop).0.unwrap();
+    tokio::join!(main_loop).0.unwrap()
 }

phantun/src/utils.rs

@@ -1,4 +1,15 @@
-use std::net::SocketAddr;
+use neli::{
+    consts::{
+        nl::{NlmF, NlmFFlags},
+        rtnl::{Ifa, IfaFFlags, RtAddrFamily, Rtm},
+        socket::NlFamily,
+    },
+    nl::{NlPayload, Nlmsghdr},
+    rtnl::{Ifaddrmsg, Rtattr},
+    socket::NlSocketHandle,
+    types::RtBuffer,
+};
+use std::net::{Ipv6Addr, SocketAddr};
 use tokio::net::UdpSocket;
 
 pub fn new_udp_reuseport(local_addr: SocketAddr) -> UdpSocket {
@@ -20,3 +31,30 @@ pub fn new_udp_reuseport(local_addr: SocketAddr) -> UdpSocket {
     let udp_sock: std::net::UdpSocket = udp_sock.into();
     udp_sock.try_into().unwrap()
 }
+
+pub fn assign_ipv6_address(device_name: &str, local: Ipv6Addr, peer: Ipv6Addr) {
+    let index = nix::net::if_::if_nametoindex(device_name).unwrap();
+
+    let mut rtnl = NlSocketHandle::connect(NlFamily::Route, None, &[]).unwrap();
+    let mut rtattrs = RtBuffer::new();
+    rtattrs.push(Rtattr::new(None, Ifa::Local, &local.octets()[..]).unwrap());
+    rtattrs.push(Rtattr::new(None, Ifa::Address, &peer.octets()[..]).unwrap());
+
+    let ifaddrmsg = Ifaddrmsg {
+        ifa_family: RtAddrFamily::Inet6,
+        ifa_prefixlen: 128,
+        ifa_flags: IfaFFlags::empty(),
+        ifa_scope: 0,
+        ifa_index: index as i32,
+        rtattrs,
+    };
+    let nl_header = Nlmsghdr::new(
+        None,
+        Rtm::Newaddr,
+        NlmFFlags::new(&[NlmF::Request]),
+        None,
+        None,
+        NlPayload::Payload(ifaddrmsg),
+    );
+    rtnl.send(nl_header).unwrap();
+}