Merge pull request #3

Rudimentary TCP support

Author: phil-opp

Cargo.toml

@@ -5,6 +5,8 @@ version = "0.1.0"
 license = "MIT/Apache-2.0"
 
 [dependencies]
+bit_field = "0.7.0"
+bitflags-associated-constants = "0.6.0"
 byteorder = { version = "1.0.0", default-features = false }
 
 [features]

src/ipv4.rs

@@ -1,5 +1,6 @@
 use {TxPacket, WriteOut, ip_checksum};
 use udp::UdpPacket;
+use tcp::TcpPacket;
 use icmp::IcmpPacket;
 use core::convert::TryInto;
 use core::fmt;
@@ -87,6 +88,19 @@ impl<T> Ipv4Packet<UdpPacket<T>> {
     }
 }
 
+impl<'a, T> Ipv4Packet<&'a TcpPacket<T>> {
+    pub fn new_tcp(src_addr: Ipv4Address, dst_addr: Ipv4Address, tcp: &'a TcpPacket<T>) -> Self {
+        Ipv4Packet {
+            header: Ipv4Header {
+                src_addr: src_addr,
+                dst_addr: dst_addr,
+                protocol: IpProtocol::Tcp,
+            },
+            payload: tcp,
+        }
+    }
+}
+
 impl<T> Ipv4Packet<IcmpPacket<T>> {
     pub fn new_icmp(src_addr: Ipv4Address, dst_addr: Ipv4Address, icmp: IcmpPacket<T>) -> Self {
         Ipv4Packet {
@@ -169,8 +183,32 @@ impl<T: WriteOut> WriteOut for Ipv4Packet<UdpPacket<T>> {
     }
 }
 
+impl<'a, T: WriteOut> WriteOut for Ipv4Packet<&'a TcpPacket<T>> {
+    fn write_out<P: TxPacket>(&self, packet: &mut P) -> Result<(), ()> {
+        self.write_out_impl(packet)?;
+
+        let tcp_start_index = packet.len();
+        self.payload.write_out(packet)?;
+
+        // calculate tcp checksum
+        let pseudo_header_checksum = !ip_checksum::pseudo_header(&self.header.src_addr,
+                                                                 &self.header.dst_addr,
+                                                                 self.header.protocol,
+                                                                 self.payload.len());
+
+        let tcp_checksum_idx = tcp_start_index + 16;
+        packet.update_u16(tcp_checksum_idx, |checksum| {
+            let checksums = [checksum, pseudo_header_checksum];
+            ip_checksum::combine(&checksums)
+        });
+
+        Ok(())
+    }
+}
+
 use parse::{Parse, ParseError};
 use udp::UdpKind;
+use tcp::TcpKind;
 
 impl<'a> Parse<'a> for Ipv4Packet<&'a [u8]> {
     fn parse(data: &'a [u8]) -> Result<Self, ParseError> {
@@ -191,6 +229,7 @@ impl<'a> Parse<'a> for Ipv4Packet<&'a [u8]> {
 #[derive(Debug)]
 pub enum Ipv4Kind<'a> {
     Udp(UdpPacket<UdpKind<'a>>),
+    Tcp(TcpPacket<TcpKind<'a>>),
     Icmp(IcmpPacket<&'a [u8]>),
     Unknown(u8, &'a [u8]),
 }
@@ -206,6 +245,13 @@ impl<'a> Parse<'a> for Ipv4Packet<Ipv4Kind<'a>> {
                        payload: Ipv4Kind::Udp(udp),
                    })
             }
+            IpProtocol::Tcp => {
+                let tcp = TcpPacket::parse(ip.payload)?;
+                Ok(Ipv4Packet {
+                       header: ip.header,
+                       payload: Ipv4Kind::Tcp(tcp),
+                   })
+            }
             IpProtocol::Icmp => {
                 let icmp = IcmpPacket::parse(ip.payload)?;
                 Ok(Ipv4Packet {
@@ -219,7 +265,6 @@ impl<'a> Parse<'a> for Ipv4Packet<Ipv4Kind<'a>> {
                        payload: Ipv4Kind::Unknown(number, ip.payload),
                    })
             }
-            _ => return Err(ParseError::Unimplemented("unimplemented ip protocol")),
         }
     }
 }

src/lib.rs

@@ -1,6 +1,7 @@
 #![feature(try_from)]
 #![feature(specialization)]
 #![feature(const_fn)]
+#![feature(conservative_impl_trait)]
 
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(any(test, feature = "alloc"), feature(alloc))]
@@ -9,6 +10,7 @@
 extern crate alloc;
 
 extern crate byteorder;
+extern crate bit_field;
 
 #[cfg(test)]
 mod core {
@@ -20,13 +22,17 @@ pub use parse::{parse, ParseError};
 pub use heap_tx_packet::HeapTxPacket;
 
 use core::ops::{Index, IndexMut, Range};
-use alloc::borrow::Cow;
+use core::borrow::Borrow;
 use byteorder::{ByteOrder, NetworkEndian};
 
+#[macro_use]
+extern crate bitflags_associated_constants;
+
 pub mod ethernet;
 pub mod arp;
 pub mod ipv4;
 pub mod udp;
+pub mod tcp;
 pub mod dhcp;
 pub mod icmp;
 mod ip_checksum;
@@ -85,23 +91,13 @@ pub trait WriteOut {
     fn write_out<T: TxPacket>(&self, packet: &mut T) -> Result<(), ()>;
 }
 
-impl<'a> WriteOut for &'a [u8] {
-    fn len(&self) -> usize {
-        <[u8]>::len(self)
-    }
-
-    fn write_out<T: TxPacket>(&self, packet: &mut T) -> Result<(), ()> {
-        packet.push_bytes(self).map(|_| ())
-    }
-}
-
-impl<'a> WriteOut for Cow<'a, [u8]> {
+impl<T> WriteOut for T where T: Borrow<[u8]> {
     fn len(&self) -> usize {
-        (**self).len()
+        <[u8]>::len(self.borrow())
     }
 
-    fn write_out<T: TxPacket>(&self, packet: &mut T) -> Result<(), ()> {
-        packet.push_bytes(self).map(|_| ())
+    fn write_out<P: TxPacket>(&self, packet: &mut P) -> Result<(), ()> {
+        packet.push_bytes(self.borrow()).map(|_| ())
     }
 }