Support ctnetlink messages

examples/ctnetlink.rs

@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: MIT
+
+use std::num::NonZero;
+
+use netlink_packet_core::{
+    NetlinkHeader, NetlinkMessage, NetlinkPayload, NLM_F_DUMP, NLM_F_MATCH,
+    NLM_F_REQUEST, NLM_F_ROOT,
+};
+use netlink_packet_netfilter::{
+    constants::{AF_INET, NFNETLINK_V0},
+    ctnetlink::{
+        nlas::flow::{ip_tuple::TupleNla, nla::FlowAttribute},
+        CtNetlinkMessage,
+    },
+    NetfilterHeader, NetfilterMessage, NetfilterMessageInner,
+};
+use netlink_sys::{protocols::NETLINK_NETFILTER, Socket};
+
+fn main() {
+    let mut receive_buffer = vec![0; 4096];
+
+    let mut socket = Socket::new(NETLINK_NETFILTER).unwrap();
+    socket.bind_auto().unwrap();
+
+    // List all conntrack entries
+    let packet = list_request(AF_INET, 0, false);
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+
+    // pick one ip_tuple from the result of list
+    let mut orig: Option<Vec<TupleNla>> = None;
+
+    let mut done = false;
+    loop {
+        let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+        let bytes = &receive_buffer[..size];
+        let mut read = 0;
+        let mut msg_count = 0;
+        while bytes.len() > read {
+            let rx_packet =
+                <NetlinkMessage<NetfilterMessage>>::deserialize(&bytes[read..])
+                    .unwrap();
+            if let NetlinkPayload::Done(_) = rx_packet.payload {
+                done = true;
+                break;
+            }
+            read += rx_packet.buffer_len();
+            msg_count += 1;
+            println!(
+                "<<< counter={} packet_len={}\n{:?}",
+                msg_count,
+                rx_packet.buffer_len(),
+                rx_packet
+            );
+
+            if let NetlinkPayload::InnerMessage(ct) = rx_packet.payload {
+                if let NetfilterMessageInner::CtNetlink(
+                    CtNetlinkMessage::New(nlas),
+                ) = ct.inner
+                {
+                    for nla in nlas.iter() {
+                        if let FlowAttribute::Orig(attrs) = nla {
+                            orig = Some(attrs.clone())
+                        }
+                    }
+                }
+            } else if let NetlinkPayload::Error(e) = rx_packet.payload {
+                println!("{}", e);
+                assert_eq!(e.code, None);
+            }
+        }
+        if done {
+            break;
+        }
+    }
+
+    // Get a specific conntrack entry
+    let orig = orig.unwrap();
+    let packet = get_request(AF_INET, 0, orig.clone());
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+
+    let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+    let bytes = &receive_buffer[..size];
+    let rx_packet =
+        <NetlinkMessage<NetfilterMessage>>::deserialize(bytes).unwrap();
+    println!("<<< packet_len={}\n{:?}", rx_packet.buffer_len(), rx_packet);
+
+    // Delete one entry
+    let packet = delete_request(AF_INET, 0, orig.clone());
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+
+    // Confirm the etntry is deleted
+    let packet = get_request(AF_INET, 0, orig.clone());
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+
+    let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+    let bytes = &receive_buffer[..size];
+    let rx_packet =
+        <NetlinkMessage<NetfilterMessage>>::deserialize(bytes).unwrap();
+    println!("<<< packet_len={}\n{:?}", rx_packet.buffer_len(), rx_packet);
+    if let NetlinkPayload::Error(e) = rx_packet.payload {
+        if let Some(code) = e.code {
+            if NonZero::new(-2).unwrap().ne(&code) {
+                panic!("found the other error");
+            }
+        }
+    } else {
+        panic!("NetlinkPayload::Error is expected");
+    }
+
+    println!(">>> An entry is deleted correctly");
+
+    // stat
+    let packet = stat_request(AF_INET, 0);
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+    let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+    let bytes = &receive_buffer[..size];
+    let rx_packet =
+        <NetlinkMessage<NetfilterMessage>>::deserialize(bytes).unwrap();
+    println!("<<< packet_len={}\n{:?}", rx_packet.buffer_len(), rx_packet);
+
+    // stat CPU
+    let packet = stat_cpu_request(AF_INET, 0);
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+
+    let mut done = false;
+    loop {
+        let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+        let bytes = &receive_buffer[..size];
+        let mut read = 0;
+        let mut msg_count = 0;
+        while bytes.len() > read {
+            let rx_packet =
+                <NetlinkMessage<NetfilterMessage>>::deserialize(&bytes[read..])
+                    .unwrap();
+            if let NetlinkPayload::Done(_) = rx_packet.payload {
+                done = true;
+                break;
+            }
+            read += rx_packet.buffer_len();
+            msg_count += 1;
+            println!(
+                "<<< counter={} packet_len={}\n{:?}",
+                msg_count,
+                rx_packet.buffer_len(),
+                rx_packet
+            );
+
+            if let NetlinkPayload::Error(e) = rx_packet.payload {
+                println!("{}", e);
+                assert_eq!(e.code, None);
+            }
+        }
+        if done {
+            break;
+        }
+    }
+
+    // List all conntrack entries
+    let packet = list_request(AF_INET, 0, true);
+    let mut buf = vec![0; packet.header.length as usize];
+    packet.serialize(&mut buf[..]);
+    println!(">>> {:?}", packet);
+    socket.send(&buf[..], 0).unwrap();
+    let mut done = false;
+    loop {
+        let size = socket.recv(&mut &mut receive_buffer[..], 0).unwrap();
+        let bytes = &receive_buffer[..size];
+        let mut read = 0;
+        let mut msg_count = 0;
+        while bytes.len() > read {
+            let rx_packet =
+                <NetlinkMessage<NetfilterMessage>>::deserialize(&bytes[read..])
+                    .unwrap();
+            if let NetlinkPayload::Done(_) = rx_packet.payload {
+                done = true;
+                break;
+            }
+            read += rx_packet.buffer_len();
+            msg_count += 1;
+            println!(
+                "<<< counter={} packet_len={}\n{:?}",
+                msg_count,
+                rx_packet.buffer_len(),
+                rx_packet
+            );
+
+            if let NetlinkPayload::Error(e) = rx_packet.payload {
+                println!("{}", e);
+                assert_eq!(e.code, None);
+            }
+        }
+        if done {
+            break;
+        }
+    }
+}
+
+fn list_request(
+    family: u8,
+    res_id: u16,
+    zero: bool,
+) -> NetlinkMessage<NetfilterMessage> {
+    let mut hdr = NetlinkHeader::default();
+    hdr.flags = NLM_F_REQUEST | NLM_F_DUMP;
+    let mut message = if zero {
+        NetlinkMessage::new(
+            hdr,
+            NetlinkPayload::from(NetfilterMessage::new(
+                NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+                CtNetlinkMessage::GetCrtZero(None),
+            )),
+        )
+    } else {
+        NetlinkMessage::new(
+            hdr,
+            NetlinkPayload::from(NetfilterMessage::new(
+                NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+                CtNetlinkMessage::Get(None),
+            )),
+        )
+    };
+    message.finalize();
+    message
+}
+
+fn get_request(
+    family: u8,
+    res_id: u16,
+    tuple: Vec<TupleNla>,
+) -> NetlinkMessage<NetfilterMessage> {
+    let mut hdr = NetlinkHeader::default();
+    hdr.flags = NLM_F_REQUEST;
+    let mut message = NetlinkMessage::new(
+        hdr,
+        NetlinkPayload::from(NetfilterMessage::new(
+            NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+            CtNetlinkMessage::Get(Some(vec![FlowAttribute::Orig(tuple)])),
+        )),
+    );
+    message.finalize();
+    message
+}
+
+fn delete_request(
+    family: u8,
+    res_id: u16,
+    tuple: Vec<TupleNla>,
+) -> NetlinkMessage<NetfilterMessage> {
+    let mut hdr = NetlinkHeader::default();
+    hdr.flags = NLM_F_REQUEST;
+    let mut message = NetlinkMessage::new(
+        hdr,
+        NetlinkPayload::from(NetfilterMessage::new(
+            NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+            CtNetlinkMessage::Delete(vec![FlowAttribute::Orig(tuple)]),
+        )),
+    );
+    message.finalize();
+    message
+}
+
+fn stat_request(family: u8, res_id: u16) -> NetlinkMessage<NetfilterMessage> {
+    let mut hdr = NetlinkHeader::default();
+    hdr.flags = NLM_F_REQUEST;
+    let mut message = NetlinkMessage::new(
+        hdr,
+        NetlinkPayload::from(NetfilterMessage::new(
+            NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+            CtNetlinkMessage::GetStats(None),
+        )),
+    );
+    message.finalize();
+    message
+}
+
+fn stat_cpu_request(
+    family: u8,
+    res_id: u16,
+) -> NetlinkMessage<NetfilterMessage> {
+    let mut hdr = NetlinkHeader::default();
+    hdr.flags = NLM_F_REQUEST | NLM_F_ROOT | NLM_F_MATCH;
+    let mut message = NetlinkMessage::new(
+        hdr,
+        NetlinkPayload::from(NetfilterMessage::new(
+            NetfilterHeader::new(family, NFNETLINK_V0, res_id),
+            CtNetlinkMessage::GetStatsCPU(None),
+        )),
+    );
+    message.finalize();
+    message
+}

src/buffer.rs

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: MIT
 
 use crate::{
+    ctnetlink::CtNetlinkMessage,
     message::{
         NetfilterHeader, NetfilterMessage, NetfilterMessageInner,
         NETFILTER_HEADER_LEN,
@@ -60,6 +61,10 @@ impl<'a, T: AsRef<[u8]> + ?Sized>
                 NfLogMessage::parse_with_param(buf, message_type)
                     .context("failed to parse nflog payload")?,
             ),
+            CtNetlinkMessage::SUBSYS => NetfilterMessageInner::CtNetlink(
+                CtNetlinkMessage::parse_with_param(buf, message_type)
+                    .context("failed to parse ctnetlink payload")?,
+            ),
             _ => NetfilterMessageInner::Other {
                 subsys,
                 message_type,