From d0019d718e4499d3daeca00fadbd51c18522d10b Mon Sep 17 00:00:00 2001
From: John Goerzen <jgoerzen@complete.org>
Date: Thu, 24 Sep 2020 22:49:25 -0500
Subject: [PATCH] adding

---
 src/tap.rs | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 src/tap.rs

diff --git a/src/tap.rs b/src/tap.rs
new file mode 100644
index 0000000..4520579
--- /dev/null
+++ b/src/tap.rs
@@ -0,0 +1,160 @@
+/*! tap virtual Ethernet gateway */
+
+/*
+    Copyright (C) 2019-2020 John Goerzen <jgoerzen@complete.org
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+use tun_tap::{Iface, Mode};
+
+use crate::ser::*;
+use crate::xb::*;
+use crate::xbpacket::*;
+use crate::xbrx::*;
+use bytes::*;
+use crossbeam_channel;
+use etherparse::*;
+use log::*;
+use std::convert::TryInto;
+use std::io;
+use std::io::{Read, Write};
+use std::mem::drop;
+use std::sync::Arc;
+use ifstructs::ifreq;
+use libc;
+
+pub const ETHER_BROADCAST: [u8; 6] = [0xff, 0xff, 0xff, 0xff, 0xff, 0xff];
+pub const XB_BROADCAST: u64 = 0xffff;
+
+#[derive(Clone)]
+pub struct XBTap {
+    pub myethermac: [u8; 6],
+    pub myxbmac: u64,
+    pub myethermacstr: String,
+    pub name: String,
+    pub tap: Arc<Iface>,
+}
+
+impl XBTap {
+    pub fn new_tap(myxbmac: u64) -> io::Result<XBTap> {
+        let myethermac = mac64to48(myxbmac);
+        let myethermacstr = showmac(&myethermac);
+        let tap = Iface::without_packet_info("xbnet%d", Mode::Tap)?;
+        let name = tap.name();
+
+        // Set the MAC address.
+        let mut sa_data = [0u8 as libc::c_char; 14];
+        let c_mac: Vec<libc::c_char> = myethermac[..].iter().map(|x| *x as libc::c_char).collect();
+        sa_data[0..=5].copy_from_slice(c_mac.as_slice());
+        let sockaddr = libc::sockaddr {sa_family: libc::ARPHRD_ETHER,
+                                       sa_data
+        };
+
+        let mut ifr = ifreq::from_name(name).unwrap();
+        ifr.ifr_ifru.ifr_hwaddr = sockaddr;
+
+        unsafe {
+        let socket = libc::socket(libc::AF_INET, libc::SOCK_DGRAM, 0);
+        assert!(socket >= 0);
+        let pointer: *mut ifreq = &mut ifr;
+        let ioctlres = libc::ioctl(socket, libc::SIOCSIFHWADDR, pointer);
+        assert!(ioctlres != -1);
+        libc::close(socket);
+        }
+
+        println!(
+            "Interface {} with ether MAC {} (XBee MAC {:x}) ready",
+            name,
+            myethermacstr,
+            myxbmac
+        );
+
+        let name = String::from(tap.name());
+
+        Ok(XBTap {
+            myxbmac,
+            myethermac,
+            myethermacstr,
+            name,
+            tap: Arc::new(tap),
+        })
+    }
+
+    pub fn frames_from_tap_processor(
+        &self,
+        maxframesize: usize,
+        sender: crossbeam_channel::Sender<XBTX>,
+    ) -> io::Result<()> {
+        let mut buf = [0u8; 9100]; // Enough to handle even jumbo frames
+        loop {
+            let size = self.tap.recv(&mut buf)?;
+            let tapdata = &buf[0..size];
+            trace!("TAPIN: {}", hex::encode(tapdata));
+            match SlicedPacket::from_ethernet(tapdata) {
+                Err(x) => {
+                    warn!("Error parsing packet from tap; discarding: {:?}", x);
+                }
+                Ok(packet) => {
+                    if let Some(LinkSlice::Ethernet2(header)) = packet.link {
+                        if header.source() != &self.myethermac {
+                            warn!("Packet from tap with MAC address {} mismatches my own MAC address of {}; proceeding anyway",
+                                  showmac(header.source().try_into().unwrap()), self.myethermacstr);
+                        }
+                        let destxbmac = if header.destination() == ETHER_BROADCAST {
+                            XB_BROADCAST
+                        } else {
+                            mac48to64(header.destination().try_into().unwrap(), self.myxbmac)
+                        };
+                        trace!("TAPIN: Packet is {} -> {}", hex::encode(header.source()), hex::encode(header.destination()));
+
+                        let res =
+                        sender
+                            .try_send(XBTX::TXData(
+                                XBDestAddr::U64(destxbmac),
+                                Bytes::copy_from_slice(tapdata),
+                            ));
+                        match res {
+                            Ok(()) => (),
+                            Err(crossbeam_channel::TrySendError::Full(_)) =>
+                                debug!("Dropped packet due to full TX buffer")
+                            ,
+                            Err(e) => Err(e).unwrap(),
+                        }
+                    } else {
+                        warn!("Unable to get Ethernet2 header from tap packet; discarding");
+                    }
+                }
+            }
+        }
+    }
+    pub fn frames_from_xb_processor(
+        &self,
+        xbreframer: &mut XBReframer,
+        ser: &mut XBSerReader) -> io::Result<()> {
+        loop {
+            let (_fromu64, _fromu16, payload) = xbreframer.rxframe(ser);
+            self.tap.send(&payload)?;
+        }
+    }
+}
+
+
+pub fn showmac(mac: &[u8; 6]) -> String {
+    format!(
+        "{:x}:{:x}:{:x}:{:x}:{:x}:{:x}",
+        mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]
+    )
+}