Adding DCCP support

src/lib.rs

@@ -257,6 +257,13 @@ impl Type {
     /// Used for protocols such as UDP.
     pub const DGRAM: Type = Type(sys::SOCK_DGRAM);
 
+    /// Type corresponding to `SOCK_DCCP`
+    ///
+    /// Used for the DCCP protocol
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub const DCCP: Type = Type(sys::SOCK_DCCP);
+
     /// Type corresponding to `SOCK_SEQPACKET`.
     #[cfg(feature = "all")]
     #[cfg_attr(docsrs, doc(cfg(feature = "all")))]
@@ -306,6 +313,11 @@ impl Protocol {
     #[cfg(target_os = "linux")]
     /// Protocol corresponding to `MPTCP`.
     pub const MPTCP: Protocol = Protocol(sys::IPPROTO_MPTCP);
+
+    /// Protocol corresponding to `DCCP`
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub const DCCP: Protocol = Protocol(sys::IPPROTO_DCCP);
 }
 
 impl From<c_int> for Protocol {

src/sys/unix.rs

@@ -57,12 +57,17 @@ pub(crate) use libc::c_int;
 // Used in `Domain`.
 pub(crate) use libc::{AF_INET, AF_INET6, AF_UNIX};
 // Used in `Type`.
+#[cfg(all(feature = "all", target_os = "linux"))]
+pub(crate) use libc::SOCK_DCCP;
 #[cfg(all(feature = "all", not(target_os = "redox")))]
 pub(crate) use libc::SOCK_RAW;
 #[cfg(feature = "all")]
 pub(crate) use libc::SOCK_SEQPACKET;
+
 pub(crate) use libc::{SOCK_DGRAM, SOCK_STREAM};
 // Used in `Protocol`.
+#[cfg(all(feature = "all", target_os = "linux"))]
+pub(crate) use libc::IPPROTO_DCCP;
 #[cfg(target_os = "linux")]
 pub(crate) use libc::IPPROTO_MPTCP;
 pub(crate) use libc::{IPPROTO_ICMP, IPPROTO_ICMPV6, IPPROTO_TCP, IPPROTO_UDP};
@@ -390,6 +395,8 @@ impl_debug!(
     libc::IPPROTO_UDP,
     #[cfg(target_os = "linux")]
     libc::IPPROTO_MPTCP,
+    #[cfg(target_os = "linux")]
+    libc::IPPROTO_DCCP
 );
 
 /// Unix-only API.
@@ -1997,6 +2004,162 @@ impl crate::Socket {
     pub fn detach_filter(&self) -> io::Result<()> {
         unsafe { setsockopt(self.as_raw(), libc::SOL_SOCKET, libc::SO_DETACH_FILTER, 0) }
     }
+
+    /// Returns list of CCIDs supported by the endpoint.
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_available_ccids(&self) -> io::Result<Vec<u8>> {
+        // Creating the buffer with a value of 5 is ~probably~ fine.
+        // https://www.kernel.org/doc/html/latest/networking/dccp.html says the minimum is 4, however currently there are only 3 CCIDs implemented in the kernel.
+        // So 5 should cover us for some time. Even if 3 more CCIDs are implemented it would be very unlikely, that all 6 are available.
+        let mut buf: [MaybeUninit<u8>; 5] = unsafe { MaybeUninit::uninit().assume_init() };
+        let mut len = buf.len() as libc::socklen_t;
+        syscall!(getsockopt(
+            self.as_raw(),
+            libc::SOL_DCCP,
+            libc::DCCP_SOCKOPT_AVAILABLE_CCIDS,
+            buf.as_mut_ptr().cast(),
+            &mut len,
+        ))?;
+        let buf = &buf[..len as usize - 1];
+        Ok(unsafe { &*(buf as *const [_] as *const [u8]) }.into())
+    }
+
+    /// Get the service
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_service(&self) -> io::Result<u32> {
+        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_SERVICE) }
+    }
+
+    /// Set the service
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_service(&self, code: u32) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_SERVICE,
+                code,
+            )
+        }
+    }
+
+    /// Get the current maximum packet size
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_cur_mps(&self) -> io::Result<u32> {
+        unsafe {
+            getsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_GET_CUR_MPS,
+            )
+        }
+    }
+
+    /// Set both the TX and RX CCIDs
+    /// Different TX and RX CCIDs, while in practice allowed, is rarely done and not supported by this library.
+    // todo: allow passing of multiple CCIDs
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_ccid(&self, ccid: u8) -> io::Result<()> {
+        unsafe { setsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_CCID, ccid) }
+    }
+
+    /// Get the current CCID if set.
+    /// The underlying sockopt used here is the DCCP_SOCKOPT_TX_CCID. This means that theoretically only the CCID for TX is returned.
+    /// However, in practice setting different TX and RX CCIDs is rarely used.
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_ccid(&self) -> io::Result<u32> {
+        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_TX_CCID) }
+    }
+
+    /// Enables the server to hold the timewait state when closing the connection.
+    /// Only available for listening sockets
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_server_timewait(&self, hold_timewait: bool) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_SERVER_TIMEWAIT,
+                hold_timewait as c_int,
+            )
+        }
+    }
+
+    /// Get the value of partial checksum coverage on the sender side
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_send_cscov(&self) -> io::Result<u32> {
+        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_SEND_CSCOV) }
+    }
+
+    /// Set the value of partial checksum coverage on the sender side
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_send_cscov(&self, level: u32) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_SEND_CSCOV,
+                level,
+            )
+        }
+    }
+
+    /// Get the value of partial checksum coverage on the receiver side
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_recv_cscov(&self) -> io::Result<u32> {
+        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_RECV_CSCOV) }
+    }
+
+    /// Set the value of partial checksum coverage on the receiver side
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_recv_cscov(&self, level: u32) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_RECV_CSCOV,
+                level,
+            )
+        }
+    }
+
+    /// Get the maximum length of the output queue
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_qpolicy_txqlen(&self) -> io::Result<u32> {
+        unsafe {
+            getsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_QPOLICY_TXQLEN,
+            )
+        }
+    }
+
+    /// Set the maximum length of the output queue
+    #[cfg(all(feature = "all", target_os = "linux"))]
+    #[cfg_attr(docsrs, doc(cfg(feature = "all", target_os = "linux")))]
+    pub fn dccp_set_qpolicy_txqlen(&self, qlen: u32) -> io::Result<()> {
+        unsafe {
+            setsockopt(
+                self.as_raw(),
+                libc::SOL_DCCP,
+                libc::DCCP_SOCKOPT_QPOLICY_TXQLEN,
+                qlen,
+            )
+        }
+    }
 }
 
 #[cfg_attr(docsrs, doc(cfg(unix)))]

tests/socket.rs

@@ -108,6 +108,8 @@ fn protocol_fmt_debug() {
         (Protocol::UDP, "IPPROTO_UDP"),
         #[cfg(target_os = "linux")]
         (Protocol::MPTCP, "IPPROTO_MPTCP"),
+        #[cfg(all(feature = "all", target_os = "linux"))]
+        (Protocol::DCCP, "IPPROTO_DCCP"),
         (500.into(), "500"),
     ];
 
@@ -1295,3 +1297,33 @@ fn header_included() {
     let got = socket.header_included().expect("failed to get value");
     assert_eq!(got, true, "set and get values differ");
 }
+
+#[test]
+#[cfg(all(feature = "all", target_os = "linux"))]
+fn dccp() {
+    let socket_s = Socket::new(Domain::IPV4, Type::DCCP, Some(Protocol::DCCP)).unwrap();
+    let addr = "127.0.0.1:8686".parse::<SocketAddr>().unwrap().into();
+    socket_s.dccp_set_service(45).unwrap();
+    assert!(socket_s.dccp_service().unwrap() == 45);
+    assert!(socket_s.dccp_cur_mps().unwrap() > 0);
+    assert!(socket_s.dccp_available_ccids().is_ok());
+    assert!(
+        socket_s.dccp_send_cscov().unwrap() == 0,
+        "sender cscov should be zero by default"
+    );
+    socket_s.dccp_set_ccid(2).unwrap();
+    socket_s.dccp_set_qpolicy_txqlen(6).unwrap();
+    assert!(socket_s.dccp_qpolicy_txqlen().unwrap() == 6);
+    socket_s.bind(&addr).unwrap();
+    socket_s.listen(10).unwrap();
+
+    let mut socket_c = Socket::new(Domain::IPV4, Type::DCCP, Some(Protocol::DCCP)).unwrap();
+    socket_c.dccp_set_service(45).unwrap();
+    socket_c.connect(&addr).unwrap();
+
+    let (mut socket_s_c, _) = socket_s.accept().unwrap();
+    let msg = "Hello World!";
+    assert!(socket_c.write(msg.as_bytes()).unwrap() == msg.len());
+    let mut recv_buf = [0_u8; 64];
+    assert!(socket_s_c.read(&mut recv_buf).unwrap() == msg.len());
+}