Implements recvmmsg() for UDP packets (#1161)

* Implemented recvmmsg() for UDP packets

- This change implements binding between libc API for recvmmsg()
- The function can receive multiple packets using one system call

Fixes #1141

* Added unit tests for recvmmsg()

* Added recv_mmsg() wrapper for non Linux OS

* Address review comments for recvmmsg()

* Remove unnecessary imports

* Moved target specific dependencies to the function

Cargo.toml

@@ -97,6 +97,7 @@ sys-info = "0.5.6"
 tokio = "0.1"
 tokio-codec = "0.1"
 untrusted = "0.6.2"
+libc = "0.2.43"
 
 [[bench]]
 name = "bank"

src/lib.rs

@@ -36,6 +36,7 @@ pub mod packet;
 pub mod payment_plan;
 pub mod record_stage;
 pub mod recorder;
+pub mod recvmmsg;
 pub mod replicate_stage;
 pub mod request;
 pub mod request_processor;
@@ -69,6 +70,7 @@ extern crate jsonrpc_core;
 #[macro_use]
 extern crate jsonrpc_macros;
 extern crate jsonrpc_http_server;
+extern crate libc;
 #[macro_use]
 extern crate log;
 extern crate nix;

src/packet.rs

@@ -3,6 +3,7 @@ use bincode::{deserialize, serialize};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use counter::Counter;
 use log::Level;
+use recvmmsg::{recv_mmsg, NUM_RCVMMSGS};
 use result::{Error, Result};
 use serde::Serialize;
 use signature::Pubkey;
@@ -251,31 +252,30 @@ impl Packets {
         //  * read until it fails
         //  * set it back to blocking before returning
         socket.set_nonblocking(false)?;
-        for p in &mut self.packets {
-            p.meta.size = 0;
         trace!("receiving on {}", socket.local_addr().unwrap());
-            match socket.recv_from(&mut p.data) {
+        loop {
+            match recv_mmsg(socket, &mut self.packets[i..]) {
                 Err(_) if i > 0 => {
                     inc_new_counter_info!("packets-recv_count", i);
                     debug!("got {:?} messages on {}", i, socket.local_addr().unwrap());
-                    break;
+                    socket.set_nonblocking(true)?;
+                    return Ok(i);
                 }
                 Err(e) => {
                     trace!("recv_from err {:?}", e);
                     return Err(Error::IO(e));
                 }
-                Ok((nrecv, from)) => {
+                Ok(npkts) => {
-                    p.meta.size = nrecv;
+                    trace!("got {} packets", npkts);
-                    p.meta.set_addr(&from);
+                    i += npkts;
-                    trace!("got {} bytes from {}", nrecv, from);
+                    if npkts != NUM_RCVMMSGS {
-                    if i == 0 {
                         socket.set_nonblocking(true)?;
+                        inc_new_counter_info!("packets-recv_count", i);
+                        return Ok(i);
                     }
                 }
             }
-            i += 1;
         }
-        Ok(i)
     }
     pub fn recv_from(&mut self, socket: &UdpSocket) -> Result<()> {
         let sz = self.run_read_from(socket)?;

src/recvmmsg.rs

@@ -0,0 +1,185 @@
+//! The `recvmmsg` module provides recvmmsg() API implementation
+
+use packet::Packet;
+use std::cmp;
+use std::io;
+use std::net::UdpSocket;
+
+pub const NUM_RCVMMSGS: usize = 16;
+
+#[cfg(not(target_os = "linux"))]
+pub fn recv_mmsg(socket: &UdpSocket, packets: &mut [Packet]) -> io::Result<usize> {
+    let mut i = 0;
+    socket.set_nonblocking(false)?;
+    let count = cmp::min(NUM_RCVMMSGS, packets.len());
+    for n in 0..count {
+        let p = &mut packets[n];
+        p.meta.size = 0;
+        match socket.recv_from(&mut p.data) {
+            Err(_) if i > 0 => {
+                break;
+            }
+            Err(e) => {
+                return Err(e);
+            }
+            Ok((nrecv, from)) => {
+                p.meta.size = nrecv;
+                p.meta.set_addr(&from);
+                if i == 0 {
+                    socket.set_nonblocking(true)?;
+                }
+            }
+        }
+        i += 1;
+    }
+    Ok(i)
+}
+
+#[cfg(target_os = "linux")]
+pub fn recv_mmsg(sock: &UdpSocket, packets: &mut [Packet]) -> io::Result<usize> {
+    use libc::{
+        c_void, iovec, mmsghdr, recvmmsg, sockaddr_in, socklen_t, time_t, timespec, MSG_WAITFORONE,
+    };
+    use nix::sys::socket::InetAddr;
+    use std::mem;
+    use std::os::unix::io::AsRawFd;
+
+    let mut hdrs: [mmsghdr; NUM_RCVMMSGS] = unsafe { mem::zeroed() };
+    let mut iovs: [iovec; NUM_RCVMMSGS] = unsafe { mem::zeroed() };
+    let mut addr: [sockaddr_in; NUM_RCVMMSGS] = unsafe { mem::zeroed() };
+    let addrlen = mem::size_of_val(&addr) as socklen_t;
+
+    let sock_fd = sock.as_raw_fd();
+
+    let count = cmp::min(iovs.len(), packets.len());
+
+    for i in 0..count {
+        iovs[i].iov_base = packets[i].data.as_mut_ptr() as *mut c_void;
+        iovs[i].iov_len = packets[i].data.len();
+
+        hdrs[i].msg_hdr.msg_name = &mut addr[i] as *mut _ as *mut _;
+        hdrs[i].msg_hdr.msg_namelen = addrlen;
+        hdrs[i].msg_hdr.msg_iov = &mut iovs[i];
+        hdrs[i].msg_hdr.msg_iovlen = 1;
+    }
+    let mut ts = timespec {
+        tv_sec: 1 as time_t,
+        tv_nsec: 0,
+    };
+
+    let npkts =
+        match unsafe { recvmmsg(sock_fd, &mut hdrs[0], count as u32, MSG_WAITFORONE, &mut ts) } {
+            -1 => return Err(io::Error::last_os_error()),
+            n => {
+                for i in 0..n as usize {
+                    let mut p = &mut packets[i];
+                    p.meta.size = hdrs[i].msg_len as usize;
+                    let inet_addr = InetAddr::V4(addr[i]);
+                    p.meta.set_addr(&inet_addr.to_std());
+                }
+                n as usize
+            }
+        };
+
+    Ok(npkts)
+}
+
+#[cfg(test)]
+mod tests {
+    use packet::PACKET_DATA_SIZE;
+    use recvmmsg::*;
+
+    #[test]
+    pub fn test_recv_mmsg_one_iter() {
+        let reader = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let addr = reader.local_addr().unwrap();
+        let sender = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let saddr = sender.local_addr().unwrap();
+        let sent = NUM_RCVMMSGS - 1;
+        for _ in 0..sent {
+            let data = [0; PACKET_DATA_SIZE];
+            sender.send_to(&data[..], &addr).unwrap();
+        }
+
+        let mut packets = vec![Packet::default(); NUM_RCVMMSGS];
+        let recv = recv_mmsg(&reader, &mut packets[..]).unwrap();
+        assert_eq!(sent, recv);
+        for i in 0..recv {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr);
+        }
+    }
+
+    #[test]
+    pub fn test_recv_mmsg_multi_iter() {
+        let reader = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let addr = reader.local_addr().unwrap();
+        let sender = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let saddr = sender.local_addr().unwrap();
+        let sent = NUM_RCVMMSGS + 10;
+        for _ in 0..sent {
+            let data = [0; PACKET_DATA_SIZE];
+            sender.send_to(&data[..], &addr).unwrap();
+        }
+
+        let mut packets = vec![Packet::default(); NUM_RCVMMSGS * 2];
+        let recv = recv_mmsg(&reader, &mut packets[..]).unwrap();
+        assert_eq!(NUM_RCVMMSGS, recv);
+        for i in 0..recv {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr);
+        }
+
+        let recv = recv_mmsg(&reader, &mut packets[..]).unwrap();
+        assert_eq!(sent - NUM_RCVMMSGS, recv);
+        for i in 0..recv {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr);
+        }
+    }
+
+    #[test]
+    pub fn test_recv_mmsg_multi_addrs() {
+        let reader = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let addr = reader.local_addr().unwrap();
+
+        let sender1 = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let saddr1 = sender1.local_addr().unwrap();
+        let sent1 = NUM_RCVMMSGS - 1;
+
+        let sender2 = UdpSocket::bind("127.0.0.1:0").expect("bind");
+        let saddr2 = sender2.local_addr().unwrap();
+        let sent2 = NUM_RCVMMSGS + 1;
+
+        for _ in 0..sent1 {
+            let data = [0; PACKET_DATA_SIZE];
+            sender1.send_to(&data[..], &addr).unwrap();
+        }
+
+        for _ in 0..sent2 {
+            let data = [0; PACKET_DATA_SIZE];
+            sender2.send_to(&data[..], &addr).unwrap();
+        }
+
+        let mut packets = vec![Packet::default(); NUM_RCVMMSGS * 2];
+
+        let recv = recv_mmsg(&reader, &mut packets[..]).unwrap();
+        assert_eq!(NUM_RCVMMSGS, recv);
+        for i in 0..sent1 {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr1);
+        }
+
+        for i in sent1..recv {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr2);
+        }
+
+        let recv = recv_mmsg(&reader, &mut packets[..]).unwrap();
+        assert_eq!(sent1 + sent2 - NUM_RCVMMSGS, recv);
+        for i in 0..recv {
+            assert_eq!(packets[i].meta.size, PACKET_DATA_SIZE);
+            assert_eq!(packets[i].meta.addr(), saddr2);
+        }
+    }
+}