Support of DHCPv6

Introducing `DhcpV6Client` and `DhcpV6ClientAsync` for DHCPv6.

Example could could be found at `examples/mozim_dhcpv6_sync.rs`.

Integration test case included.

Signed-off-by: Gris Ge <[email protected]>

.cargo/config.toml

@@ -1,2 +1,5 @@
 [target.x86_64-unknown-linux-gnu]
 runner = 'sudo -E'
+
+[env]
+RUST_TEST_THREADS = "1"

Cargo.toml

@@ -14,7 +14,7 @@ path = "src/lib.rs"
 rand = { version = "0.8.5", default-features = false }
 libc = "0.2.132"
 byteorder = "1.4.3"
-dhcproto = "0.9.0"
+dhcproto = "0.12.0"
 log = "0.4.17"
 etherparse = "0.13.0"
 nix = { version = "0.29.0", features = ["poll", "time", "event"] }

README.md

@@ -16,6 +16,12 @@ TODO:
  * Handle vendor difference: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/848
  * Support multiple DHCP servers with `DHCPNAK` reply.
  * Support DHCPNAK
+ * Support `DHCPDECLINE`: Client to server indicating network address is
+   already in use.
+ * Support `DHCPINFORM`: Client to server, asking only for local configuration
+   parameters; client already has externally configured network address.
+ * Rate control -- Token bucket (RFC 2698)
+ * Initial sleep before discovery/solicit(need check RFC)
 
 # Try out
 
@@ -24,5 +30,6 @@ TODO:
 # The `eth1.ep` is DHCP server interface running dnsmasq in `mozim` network
 # namespace.
 sudo ./utils/test_env_mozim &
-cargo run --example mozim_async
+cargo run --example mozim_dhcpv4_sync
+cargo run --example mozim_dhcpv6_sync
 ```

doc/dhcpv6_notes.md

@@ -0,0 +1,165 @@
+## RFC 8415
+
+Clients and servers exchange DHCP messages using UDP (see [RFC768]
+and BCP 145 [RFC8085]).  The client uses a link-local address or
+addresses determined through other mechanisms for transmitting and
+receiving DHCP messages.
+
+`All_DHCP_Relay_Agents_and_Servers`: ff02::1:2
+`All_DHCP_Servers`: ff05::1:3
+
+Clients listen for DHCP messages on UDP port 546.  Servers and relay
+agents listen for DHCP messages on UDP port 547.
+
+
+
+                Server                          Server
+            (not selected)      Client        (selected)
+
+                  v               v               v
+                  |               |               |
+                  |     Begins initialization     |
+                  |               |               |
+     start of     | _____________/|\_____________ |
+     4-message    |/ Solicit      | Solicit      \|
+     exchange     |               |               |
+              Determines          |          Determines
+             configuration        |         configuration
+                  |               |               |
+                  |\              |  ____________/|
+                  | \________     | /Advertise    |
+                  | Advertise\    |/              |
+                  |           \   |               |
+                  |      Collects Advertises      |
+                  |             \ |               |
+                  |     Selects configuration     |
+                  |               |               |
+                  | _____________/|\_____________ |
+                  |/ Request      |  Request     \|
+                  |               |               |
+                  |               |     Commits configuration
+                  |               |               |
+     end of       |               | _____________/|
+     4-message    |               |/ Reply        |
+     exchange     |               |               |
+                  |    Initialization complete    |
+                  |               |               |
+                  .               .               .
+                  .               .               .
+                  |   T1 (renewal) timer expires  |
+                  |               |               |
+     2-message    | _____________/|\_____________ |
+     exchange     |/ Renew        |  Renew       \|
+                  |               |               |
+                  |               | Commits extended lease(s)
+                  |               |               |
+                  |               | _____________/|
+                  |               |/ Reply        |
+                  .               .               .
+                  .               .               .
+                  |               |               |
+                  |      Graceful shutdown        |
+                  |               |               |
+     2-message    | _____________/|\_____________ |
+     exchange     |/ Release      |  Release     \|
+                  |               |               |
+                  |               |         Discards lease(s)
+                  |               |               |
+                  |               | _____________/|
+                  |               |/ Reply        |
+                  |               |               |
+                  v               v               v
+
+
+The IAID uniquely identifies the IA and MUST be chosen to be unique
+among the IAIDs for that IA type on the client (e.g., an IA_NA with
+an IAID of 0 and an IA_PD with an IAID of 0 are each considered
+unique).  The IAID is chosen by the client.  For any given use of an
+IA by the client, the IAID for that IA MUST be consistent across
+restarts of the DHCP client.
+
+
+
+       0                   1                   2                   3
+       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |    msg-type   |               transaction-id                  |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                                                               |
+      .                            options                            .
+      .                 (variable number and length)                  .
+      |                                                               |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+                  Figure 2: Client/Server Message Format
+
+
+16.2.  Solicit Message
+
+   Clients MUST discard any received Solicit messages.
+
+   Servers MUST discard any Solicit messages that do not include a
+   Client Identifier option or that do include a Server Identifier
+   option.
+
+16.3.  Advertise Message
+
+   Clients MUST discard any received Advertise message that meets any of
+   the following conditions:
+
+   -  the message does not include a Server Identifier option (see
+      Section 21.3).
+
+   -  the message does not include a Client Identifier option (see
+      Section 21.2).
+
+   -  the contents of the Client Identifier option do not match the
+      client's DUID.
+
+   -  the "transaction-id" field value does not match the value the
+      client used in its Solicit message.
+
+   Servers and relay agents MUST discard any received Advertise
+   messages.
+
+
+16.4.  Request Message
+
+   Clients MUST discard any received Request messages.
+
+   Servers MUST discard any received Request message that meets any of
+   the following conditions:
+
+   -  the message does not include a Server Identifier option (see
+      Section 21.3).
+
+   -  the contents of the Server Identifier option do not match the
+      server's DUID.
+
+   -  the message does not include a Client Identifier option (see
+      Section 21.2).
+
+
+16.6.  Renew Message
+
+   Clients MUST discard any received Renew messages.
+
+   Servers MUST discard any received Renew message that meets any of the
+   following conditions:
+
+   -  the message does not include a Server Identifier option (see
+      Section 21.3).
+
+   -  the contents of the Server Identifier option do not match the
+      server's identifier.
+
+   -  the message does not include a Client Identifier option (see
+      Section 21.2).
+
+16.7.  Rebind Message
+
+   Clients MUST discard any received Rebind messages.
+
+   Servers MUST discard any received Rebind messages that do not include
+   a Client Identifier option (see Section 21.2) or that do include a
+   Server Identifier option (see Section 21.3).

examples/mozim_dhcpv6_sync.rs

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use mozim::{DhcpV6Client, DhcpV6Config, DhcpV6IaType};
+
+const TEST_NIC: &str = "dhcpcli";
+const POLL_WAIT_TIME: u32 = 5;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    enable_log();
+    let mut config =
+        DhcpV6Config::new(TEST_NIC, DhcpV6IaType::NonTemporaryAddresses);
+    config.set_timeout(60);
+    let mut cli = DhcpV6Client::init(config, None).unwrap();
+
+    loop {
+        for event in cli.poll(POLL_WAIT_TIME)? {
+            if let Some(lease) = cli.process(event)? {
+                println!("Got DHCPv6 lease {:?}", lease);
+            }
+        }
+    }
+}
+
+fn enable_log() {
+    env_logger::Builder::new()
+        .filter(Some("nispor"), log::LevelFilter::Debug)
+        .filter(Some("mozim"), log::LevelFilter::Debug)
+        .init();
+}

src/client_async.rs

@@ -11,7 +11,10 @@ use futures::{
 };
 use nix::poll::{PollFd, PollFlags};
 
-use crate::{DhcpError, DhcpV4Client, DhcpV4Config, DhcpV4Lease, ErrorKind};
+use crate::{
+    DhcpError, DhcpV4Client, DhcpV4Config, DhcpV4Lease, DhcpV6Client,
+    DhcpV6Config, DhcpV6Lease, ErrorKind,
+};
 
 const POLL_TIMEOUT: u16 = 1000; // milliseconds
 
@@ -156,3 +159,85 @@ fn poll_thread(fd: RawFd, share_state: Arc<Mutex<ShareState>>) {
         }
     }
 }
+
+#[derive(Debug)]
+pub struct DhcpV6ClientAsync {
+    client: DhcpV6Client,
+    share_state: Arc<Mutex<ShareState>>,
+}
+
+impl Stream for DhcpV6ClientAsync {
+    type Item = Result<DhcpV6Lease, DhcpError>;
+
+    fn poll_next(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Option<Self::Item>> {
+        // Poll without wait
+        match self.client.poll(0) {
+            Ok(events) => {
+                for event in events {
+                    match self.client.process(event) {
+                        Ok(Some(lease)) => {
+                            return Poll::Ready(Some(Ok(lease)));
+                        }
+                        Ok(None) => (),
+                        Err(e) => {
+                            return Poll::Ready(Some(Err(e)));
+                        }
+                    }
+                }
+            }
+            Err(e) => {
+                log::error!("DHCP client poll error: {e}");
+                return Poll::Ready(Some(Err(e)));
+            }
+        }
+
+        let mut share_state = match self.share_state.lock() {
+            Ok(s) => s,
+            Err(e) => {
+                return Poll::Ready(Some(Err(DhcpError::new(
+                    ErrorKind::Bug,
+                    format!(
+                        "BUG: DhcpV6ClientAsync::poll_next() \
+                        Failed to acquire lock on share_state {e}",
+                    ),
+                ))));
+            }
+        };
+        if share_state.waker.is_none() {
+            share_state.waker = Some(cx.waker().clone());
+            drop(share_state);
+            let fd = self.client.as_raw_fd();
+            let share_state = self.share_state.clone();
+            std::thread::spawn(move || poll_thread(fd, share_state));
+        } else {
+            share_state.waker = Some(cx.waker().clone());
+            drop(share_state);
+        }
+
+        Poll::Pending
+    }
+}
+
+impl DhcpV6ClientAsync {
+    pub fn init(
+        config: DhcpV6Config,
+        lease: Option<DhcpV6Lease>,
+    ) -> Result<Self, DhcpError> {
+        Ok(Self {
+            client: DhcpV6Client::init(config, lease)?,
+            share_state: Arc::new(Mutex::new(ShareState { waker: None })),
+        })
+    }
+}
+
+impl std::ops::Drop for DhcpV6ClientAsync {
+    fn drop(&mut self) {
+        if let Ok(mut s) = self.share_state.lock() {
+            // Signal `poll_thread()` to quit
+            s.waker = None;
+        }
+    }
+}