Add support for RecvOrigDstAddr on Linux

Fixes nix-rust#1767

src/sys/socket/mod.rs

@@ -757,6 +757,14 @@ pub enum ControlMessageOwned {
     #[cfg(feature = "net")]
     #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
     Ipv4RecvDstAddr(libc::in_addr),
+    #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+    #[cfg(feature = "net")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+    Ipv4RecvOrigDstAddr(libc::in_addr),
+    #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+    #[cfg(feature = "net")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+    Ipv6RecvOrigDstAddr(libc::in6_addr),
 
     /// UDP Generic Receive Offload (GRO) allows receiving multiple UDP
     /// packets from a single sender.
@@ -916,6 +924,12 @@ impl ControlMessageOwned {
                 let dl = ptr::read_unaligned(p as *const libc::in_addr);
                 ControlMessageOwned::Ipv4RecvDstAddr(dl)
             },
+            #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+            #[cfg(feature = "net")]
+            (libc::IPPROTO_IP, libc::IP_RECVORIGDSTADDR) => {
+                let dl = ptr::read_unaligned(p as *const libc::in_addr);
+                ControlMessageOwned::Ipv4RecvOrigDstAddr(dl)
+            },
             #[cfg(target_os = "linux")]
             #[cfg(feature = "net")]
             (libc::SOL_UDP, libc::UDP_GRO) => {
@@ -939,6 +953,12 @@ impl ControlMessageOwned {
                 let (err, addr) = Self::recv_err_helper::<sockaddr_in6>(p, len);
                 ControlMessageOwned::Ipv6RecvErr(err, addr)
             },
+            #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+            #[cfg(feature = "net")]
+            (libc::IPPROTO_IPV6, libc::IPV6_RECVORIGDSTADDR) => {
+                let dl = ptr::read_unaligned(p as *const libc::in6_addr);
+                ControlMessageOwned::Ipv6RecvOrigDstAddr(dl)
+            },
             (_, _) => {
                 let sl = slice::from_raw_parts(p, len);
                 let ucmsg = UnknownCmsg(*header, Vec::<u8>::from(sl));

src/sys/socket/sockopt.rs

@@ -574,6 +574,13 @@ sockopt_impl!(
     /// The `recvmsg(2)` call will return the destination IP address for a UDP
     /// datagram.
     Ipv4RecvDstAddr, Both, libc::IPPROTO_IP, libc::IP_RECVDSTADDR, bool);
+#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+#[cfg(feature = "net")]
+sockopt_impl!(
+    #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+    /// The `recvmsg(2)` call will return the destination IP address for a UDP
+    /// datagram.
+    Ipv4RecvOrigDstAddr, Both, libc::IPPROTO_IP, libc::IP_RECVORIGDSTADDR, bool);
 #[cfg(target_os = "linux")]
 #[cfg(feature = "net")]
 sockopt_impl!(
@@ -621,6 +628,13 @@ sockopt_impl!(
 sockopt_impl!(
     /// Set the unicast hop limit for the socket.
     Ipv6Ttl, Both, libc::IPPROTO_IPV6, libc::IPV6_UNICAST_HOPS, libc::c_int);
+#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+#[cfg(feature = "net")]
+sockopt_impl!(
+    #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+    /// The `recvmsg(2)` call will return the destination IP address for a UDP
+    /// datagram.
+    Ipv6RecvOrigDstAddr, Both, libc::IPPROTO_IPV6, libc::IPV6_RECVORIGDSTADDR, bool);
 #[cfg(any(target_os = "ios", target_os = "macos"))]
 sockopt_impl!(
     /// Set "don't fragment packet" flag on the IP packet.

test/sys/test_socket.rs

@@ -1745,6 +1745,174 @@ pub fn test_recvif() {
     }
 }
 
+#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+#[test]
+pub fn test_recvif_ipv4() {
+    use nix::sys::socket::sockopt::{Ipv4RecvOrigDstAddr};
+    use nix::sys::socket::{bind, SockFlag, SockType, SockaddrIn};
+    use nix::sys::socket::{getsockname, setsockopt, socket};
+    use nix::sys::socket::{recvmsg, sendmsg, ControlMessageOwned, MsgFlags};
+    use std::io::{IoSlice, IoSliceMut};
+
+    let lo_ifaddr = loopback_address(AddressFamily::Inet);
+    let (_lo_name, lo) = match lo_ifaddr {
+        Some(ifaddr) => (
+            ifaddr.interface_name,
+            ifaddr.address.expect("Expect IPv4 address on interface"),
+        ),
+        None => return,
+    };
+    let receive = socket(
+        AddressFamily::Inet,
+        SockType::Datagram,
+        SockFlag::empty(),
+        None,
+    )
+    .expect("receive socket failed");
+    bind(receive, &lo).expect("bind failed");
+    let sa: SockaddrIn = getsockname(receive).expect("getsockname failed");
+    setsockopt(receive, Ipv4RecvOrigDstAddr, &true)
+        .expect("setsockopt IP_RECVORIGDSTADDR failed");
+
+    {
+        let slice = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let iov = [IoSlice::new(&slice)];
+
+        let send = socket(
+            AddressFamily::Inet,
+            SockType::Datagram,
+            SockFlag::empty(),
+            None,
+        )
+        .expect("send socket failed");
+        sendmsg(send, &iov, &[], MsgFlags::empty(), Some(&sa))
+            .expect("sendmsg failed");
+    }
+
+    {
+        let mut buf = [0u8; 8];
+        let mut iovec = [IoSliceMut::new(&mut buf)];
+        let mut space = cmsg_space!(libc::sockaddr_in);
+        let msg = recvmsg::<()>(
+            receive,
+            &mut iovec,
+            Some(&mut space),
+            MsgFlags::empty(),
+        )
+        .expect("recvmsg failed");
+        assert!(!msg
+            .flags
+            .intersects(MsgFlags::MSG_TRUNC | MsgFlags::MSG_CTRUNC));
+        assert_eq!(msg.cmsgs().count(), 1, "expected 1 cmsgs");
+
+        let mut rx_recvorigdstaddr = false;
+        for cmsg in msg.cmsgs() {
+            match cmsg {
+                ControlMessageOwned::Ipv4RecvOrigDstAddr(addr) => {
+                    rx_recvorigdstaddr = true;
+                    if let Some(sin) = lo.as_sockaddr_in() {
+                        assert_eq!(sin.as_ref().sin_addr.s_addr,
+                                   addr.s_addr,
+                                   "unexpected destination address (expected {}, got {})",
+                                   sin.as_ref().sin_addr.s_addr,
+                                   addr.s_addr);
+                    } else {
+                        panic!("unexpected Sockaddr");
+                    }
+                }
+                _ => panic!("unexpected additional control msg"),
+            }
+        }
+        assert!(rx_recvorigdstaddr);
+        assert_eq!(msg.bytes, 8);
+        assert_eq!(*iovec[0], [1u8, 2, 3, 4, 5, 6, 7, 8]);
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
+#[test]
+pub fn test_recvif_ipv6() {
+    use nix::sys::socket::sockopt::{Ipv6RecvOrigDstAddr};
+    use nix::sys::socket::{bind, SockFlag, SockType, SockaddrIn6};
+    use nix::sys::socket::{getsockname, setsockopt, socket};
+    use nix::sys::socket::{recvmsg, sendmsg, ControlMessageOwned, MsgFlags};
+    use std::io::{IoSlice, IoSliceMut};
+
+    let lo_ifaddr = loopback_address(AddressFamily::Inet6);
+    let (_lo_name, lo) = match lo_ifaddr {
+        Some(ifaddr) => (
+            ifaddr.interface_name,
+            ifaddr.address.expect("Expect IPv6 address on interface"),
+        ),
+        None => return,
+    };
+    let receive = socket(
+        AddressFamily::Inet6,
+        SockType::Datagram,
+        SockFlag::empty(),
+        None,
+    )
+    .expect("receive socket failed");
+    bind(receive, &lo).expect("bind failed");
+    let sa: SockaddrIn6 = getsockname(receive).expect("getsockname failed");
+    setsockopt(receive, Ipv6RecvOrigDstAddr, &true)
+        .expect("setsockopt IP_RECVORIGDSTADDR failed");
+
+    {
+        let slice = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let iov = [IoSlice::new(&slice)];
+
+        let send = socket(
+            AddressFamily::Inet6,
+            SockType::Datagram,
+            SockFlag::empty(),
+            None,
+        )
+        .expect("send socket failed");
+        sendmsg(send, &iov, &[], MsgFlags::empty(), Some(&sa))
+            .expect("sendmsg failed");
+    }
+
+    {
+        let mut buf = [0u8; 8];
+        let mut iovec = [IoSliceMut::new(&mut buf)];
+        let mut space = cmsg_space!(libc::sockaddr_in6);
+        let msg = recvmsg::<()>(
+            receive,
+            &mut iovec,
+            Some(&mut space),
+            MsgFlags::empty(),
+        )
+        .expect("recvmsg failed");
+        assert!(!msg
+            .flags
+            .intersects(MsgFlags::MSG_TRUNC | MsgFlags::MSG_CTRUNC));
+        assert_eq!(msg.cmsgs().count(), 1, "expected 1 cmsgs");
+
+        let mut rx_recvorigdstaddr = false;
+        for cmsg in msg.cmsgs() {
+            match cmsg {
+                ControlMessageOwned::Ipv6RecvOrigDstAddr(addr) => {
+                    rx_recvorigdstaddr = true;
+                    if let Some(sin) = lo.as_sockaddr_in6() {
+                        assert_eq!(sin.as_ref().sin6_addr.s6_addr,
+                                   addr.s6_addr,
+                                   "unexpected destination address (expected {:?}, got {:?})",
+                                   sin.as_ref().sin6_addr.s6_addr,
+                                   addr.s6_addr);
+                    } else {
+                        panic!("unexpected Sockaddr");
+                    }
+                }
+                _ => panic!("unexpected additional control msg"),
+            }
+        }
+        assert!(rx_recvorigdstaddr);
+        assert_eq!(msg.bytes, 8);
+        assert_eq!(*iovec[0], [1u8, 2, 3, 4, 5, 6, 7, 8]);
+    }
+}
+
 #[cfg(any(
     target_os = "android",
     target_os = "freebsd",