feat(API): AddListenSocket endpoint

rosenpass/Cargo.toml

@@ -23,7 +23,7 @@ name = "api-integration-tests"
 required-features = ["experiment_api", "internal_testing"]
 
 [[test]]
-name = "api-integration-tests-supply-keypair"
+name = "api-integration-tests-api-setup"
 required-features = ["experiment_api", "internal_testing"]
 
 [[bench]]

rosenpass/src/api/api_handler.rs

@@ -2,9 +2,13 @@ use std::{borrow::BorrowMut, collections::VecDeque, os::fd::OwnedFd};
 
 use anyhow::Context;
 use rosenpass_to::{ops::copy_slice, To};
-use rosenpass_util::{fd::FdIo, functional::run, io::ReadExt, mem::DiscardResultExt};
+use rosenpass_util::{
+    fd::FdIo, functional::run, io::ReadExt, mem::DiscardResultExt, result::OkExt,
+};
 
-use crate::{app_server::AppServer, protocol::BuildCryptoServer};
+use crate::{
+    api::add_listen_socket_response_status, app_server::AppServer, protocol::BuildCryptoServer,
+};
 
 use super::{supply_keypair_response_status, Server as ApiServer};
 
@@ -171,4 +175,54 @@ where
 
         Ok(())
     }
+
+    fn add_listen_socket(
+        &mut self,
+        _req: &super::boilerplate::AddListenSocketRequest,
+        req_fds: &mut VecDeque<OwnedFd>,
+        res: &mut super::boilerplate::AddListenSocketResponse,
+    ) -> anyhow::Result<()> {
+        // Retrieve file descriptor
+        let sock_res = run(|| -> anyhow::Result<mio::net::UdpSocket> {
+            let sock = req_fds
+                .pop_front()
+                .context("Invalid request – socket missing.")?;
+            // TODO: We need to have this outside linux
+            #[cfg(target_os = "linux")]
+            rosenpass_util::fd::GetSocketProtocol::demand_udp_socket(&sock)?;
+            let sock = std::net::UdpSocket::from(sock);
+            sock.set_nonblocking(true)?;
+            mio::net::UdpSocket::from_std(sock).ok()
+        });
+
+        let mut sock = match sock_res {
+            Ok(sock) => sock,
+            Err(e) => {
+                log::debug!("Error processing AddListenSocket API request: {e:?}");
+                res.payload.status = add_listen_socket_response_status::INVALID_REQUEST;
+                return Ok(());
+            }
+        };
+
+        // Register socket
+        let reg_result = run(|| -> anyhow::Result<()> {
+            let srv = self.app_server_mut();
+            srv.mio_poll.registry().register(
+                &mut sock,
+                srv.mio_token_dispenser.dispense(),
+                mio::Interest::READABLE,
+            )?;
+            srv.sockets.push(sock);
+            Ok(())
+        });
+
+        if let Err(internal_error) = reg_result {
+            log::warn!("Internal error processing AddListenSocket API request: {internal_error:?}");
+            res.payload.status = add_listen_socket_response_status::INTERNAL_ERROR;
+            return Ok(());
+        };
+
+        res.payload.status = add_listen_socket_response_status::OK;
+        Ok(())
+    }
 }

rosenpass/src/api/boilerplate/byte_slice_ext.rs

@@ -143,6 +143,44 @@ pub trait ByteSliceRefExt: ByteSlice {
     ) -> anyhow::Result<Ref<Self, SupplyKeypairResponse>> {
         self.zk_parse_suffix()
     }
+
+    fn add_listen_socket_request(self) -> anyhow::Result<Ref<Self, super::AddListenSocketRequest>> {
+        self.zk_parse()
+    }
+
+    fn add_listen_socket_request_from_prefix(
+        self,
+    ) -> anyhow::Result<Ref<Self, super::AddListenSocketRequest>> {
+        self.zk_parse_prefix()
+    }
+
+    fn add_listen_socket_request_from_suffix(
+        self,
+    ) -> anyhow::Result<Ref<Self, super::AddListenSocketRequest>> {
+        self.zk_parse_suffix()
+    }
+
+    fn add_listen_socket_response_maker(self) -> RefMaker<Self, super::AddListenSocketResponse> {
+        self.zk_ref_maker()
+    }
+
+    fn add_listen_socket_response(
+        self,
+    ) -> anyhow::Result<Ref<Self, super::AddListenSocketResponse>> {
+        self.zk_parse()
+    }
+
+    fn add_listen_socket_response_from_prefix(
+        self,
+    ) -> anyhow::Result<Ref<Self, super::AddListenSocketResponse>> {
+        self.zk_parse_prefix()
+    }
+
+    fn add_listen_socket_response_from_suffix(
+        self,
+    ) -> anyhow::Result<Ref<Self, super::AddListenSocketResponse>> {
+        self.zk_parse_suffix()
+    }
 }
 
 impl<B: ByteSlice> ByteSliceRefExt for B {}

rosenpass/src/api/boilerplate/message_type.rs

@@ -21,6 +21,13 @@ const SUPPLY_KEYPAIR_REQUEST: RawMsgType =
 const SUPPLY_KEYPAIR_RESPONSE: RawMsgType =
     RawMsgType::from_le_bytes(hex!("f2dc 49bd e261 5f10    40b7 3c16 ec61 edb9"));
 
+// hash domain hash of: Rosenpass IPC API -> Rosenpass Protocol Server -> Add Listen Socket Request
+const ADD_LISTEN_SOCKET_REQUEST: RawMsgType =
+    RawMsgType::from_le_bytes(hex!("3f21 434f 87cc a08c    02c4 61e4 0816 c7da"));
+// hash domain hash of: Rosenpass IPC API -> Rosenpass Protocol Server -> Add Listen Socket Response
+const ADD_LISTEN_SOCKET_RESPONSE: RawMsgType =
+    RawMsgType::from_le_bytes(hex!("45d5 0f0d 93f0 6105    98f2 9469 5dfd 5f36"));
+
 pub trait MessageAttributes {
     fn message_size(&self) -> usize;
 }
@@ -29,12 +36,14 @@ pub trait MessageAttributes {
 pub enum RequestMsgType {
     Ping,
     SupplyKeypair,
+    AddListenSocket,
 }
 
 #[derive(Hash, PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
 pub enum ResponseMsgType {
     Ping,
     SupplyKeypair,
+    AddListenSocket,
 }
 
 impl MessageAttributes for RequestMsgType {
@@ -42,6 +51,7 @@ impl MessageAttributes for RequestMsgType {
         match self {
             Self::Ping => std::mem::size_of::<super::PingRequest>(),
             Self::SupplyKeypair => std::mem::size_of::<super::SupplyKeypairRequest>(),
+            Self::AddListenSocket => std::mem::size_of::<super::AddListenSocketRequest>(),
         }
     }
 }
@@ -51,6 +61,7 @@ impl MessageAttributes for ResponseMsgType {
         match self {
             Self::Ping => std::mem::size_of::<super::PingResponse>(),
             Self::SupplyKeypair => std::mem::size_of::<super::SupplyKeypairResponse>(),
+            Self::AddListenSocket => std::mem::size_of::<super::AddListenSocketResponse>(),
         }
     }
 }
@@ -63,6 +74,7 @@ impl TryFrom<RawMsgType> for RequestMsgType {
         Ok(match value {
             self::PING_REQUEST => E::Ping,
             self::SUPPLY_KEYPAIR_REQUEST => E::SupplyKeypair,
+            self::ADD_LISTEN_SOCKET_REQUEST => E::AddListenSocket,
             _ => return Err(InvalidApiMessageType(value)),
         })
     }
@@ -74,6 +86,7 @@ impl From<RequestMsgType> for RawMsgType {
         match val {
             E::Ping => self::PING_REQUEST,
             E::SupplyKeypair => self::SUPPLY_KEYPAIR_REQUEST,
+            E::AddListenSocket => self::ADD_LISTEN_SOCKET_REQUEST,
         }
     }
 }
@@ -86,6 +99,7 @@ impl TryFrom<RawMsgType> for ResponseMsgType {
         Ok(match value {
             self::PING_RESPONSE => E::Ping,
             self::SUPPLY_KEYPAIR_RESPONSE => E::SupplyKeypair,
+            self::ADD_LISTEN_SOCKET_RESPONSE => E::AddListenSocket,
             _ => return Err(InvalidApiMessageType(value)),
         })
     }
@@ -97,6 +111,7 @@ impl From<ResponseMsgType> for RawMsgType {
         match val {
             E::Ping => self::PING_RESPONSE,
             E::SupplyKeypair => self::SUPPLY_KEYPAIR_RESPONSE,
+            E::AddListenSocket => self::ADD_LISTEN_SOCKET_RESPONSE,
         }
     }
 }

rosenpass/src/api/boilerplate/payload.rs

@@ -181,3 +181,87 @@ impl Message for SupplyKeypairResponse {
         self.msg_type = Self::MESSAGE_TYPE.into();
     }
 }
+
+#[repr(packed)]
+#[derive(Debug, Copy, Clone, Hash, AsBytes, FromBytes, FromZeroes, PartialEq, Eq)]
+pub struct AddListenSocketRequestPayload {}
+
+pub type AddListenSocketRequest = RequestEnvelope<AddListenSocketRequestPayload>;
+
+impl Default for AddListenSocketRequest {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl AddListenSocketRequest {
+    pub fn new() -> Self {
+        Self::from_payload(AddListenSocketRequestPayload {})
+    }
+}
+
+impl Message for AddListenSocketRequest {
+    type Payload = AddListenSocketRequestPayload;
+    type MessageClass = RequestMsgType;
+    const MESSAGE_TYPE: Self::MessageClass = RequestMsgType::AddListenSocket;
+
+    fn from_payload(payload: Self::Payload) -> Self {
+        Self {
+            msg_type: Self::MESSAGE_TYPE.into(),
+            payload,
+        }
+    }
+
+    fn setup<B: ByteSliceMut>(buf: B) -> anyhow::Result<Ref<B, Self>> {
+        let mut r: Ref<B, Self> = buf.zk_zeroized()?;
+        r.init();
+        Ok(r)
+    }
+
+    fn init(&mut self) {
+        self.msg_type = Self::MESSAGE_TYPE.into();
+    }
+}
+
+pub mod add_listen_socket_response_status {
+    pub const OK: u128 = 0;
+    pub const INVALID_REQUEST: u128 = 1;
+    pub const INTERNAL_ERROR: u128 = 2;
+}
+
+#[repr(packed)]
+#[derive(Debug, Copy, Clone, Hash, AsBytes, FromBytes, FromZeroes, PartialEq, Eq)]
+pub struct AddListenSocketResponsePayload {
+    pub status: u128,
+}
+
+pub type AddListenSocketResponse = ResponseEnvelope<AddListenSocketResponsePayload>;
+
+impl AddListenSocketResponse {
+    pub fn new(status: u128) -> Self {
+        Self::from_payload(AddListenSocketResponsePayload { status })
+    }
+}
+
+impl Message for AddListenSocketResponse {
+    type Payload = AddListenSocketResponsePayload;
+    type MessageClass = ResponseMsgType;
+    const MESSAGE_TYPE: Self::MessageClass = ResponseMsgType::AddListenSocket;
+
+    fn from_payload(payload: Self::Payload) -> Self {
+        Self {
+            msg_type: Self::MESSAGE_TYPE.into(),
+            payload,
+        }
+    }
+
+    fn setup<B: ByteSliceMut>(buf: B) -> anyhow::Result<Ref<B, Self>> {
+        let mut r: Ref<B, Self> = buf.zk_zeroized()?;
+        r.init();
+        Ok(r)
+    }
+
+    fn init(&mut self) {
+        self.msg_type = Self::MESSAGE_TYPE.into();
+    }
+}

rosenpass/src/api/boilerplate/request_ref.rs

@@ -26,6 +26,7 @@ impl<B: ByteSlice> RequestRef<B> {
         match self {
             Self::Ping(_) => RequestMsgType::Ping,
             Self::SupplyKeypair(_) => RequestMsgType::SupplyKeypair,
+            Self::AddListenSocket(_) => RequestMsgType::AddListenSocket,
         }
     }
 }
@@ -36,6 +37,18 @@ impl<B> From<Ref<B, PingRequest>> for RequestRef<B> {
     }
 }
 
+impl<B> From<Ref<B, super::SupplyKeypairRequest>> for RequestRef<B> {
+    fn from(v: Ref<B, super::SupplyKeypairRequest>) -> Self {
+        Self::SupplyKeypair(v)
+    }
+}
+
+impl<B> From<Ref<B, super::AddListenSocketRequest>> for RequestRef<B> {
+    fn from(v: Ref<B, super::AddListenSocketRequest>) -> Self {
+        Self::AddListenSocket(v)
+    }
+}
+
 impl<B: ByteSlice> RequestRefMaker<B> {
     fn new(buf: B) -> anyhow::Result<Self> {
         let msg_type = buf.deref().request_msg_type_from_prefix()?;
@@ -52,6 +65,9 @@ impl<B: ByteSlice> RequestRefMaker<B> {
             RequestMsgType::SupplyKeypair => {
                 RequestRef::SupplyKeypair(self.buf.supply_keypair_request()?)
             }
+            RequestMsgType::AddListenSocket => {
+                RequestRef::AddListenSocket(self.buf.add_listen_socket_request()?)
+            }
         })
     }
 
@@ -87,6 +103,7 @@ impl<B: ByteSlice> RequestRefMaker<B> {
 pub enum RequestRef<B> {
     Ping(Ref<B, PingRequest>),
     SupplyKeypair(Ref<B, super::SupplyKeypairRequest>),
+    AddListenSocket(Ref<B, super::AddListenSocketRequest>),
 }
 
 impl<B> RequestRef<B>
@@ -97,6 +114,7 @@ where
         match self {
             Self::Ping(r) => r.bytes(),
             Self::SupplyKeypair(r) => r.bytes(),
+            Self::AddListenSocket(r) => r.bytes(),
         }
     }
 }
@@ -109,6 +127,7 @@ where
         match self {
             Self::Ping(r) => r.bytes_mut(),
             Self::SupplyKeypair(r) => r.bytes_mut(),
+            Self::AddListenSocket(r) => r.bytes_mut(),
         }
     }
 }

rosenpass/src/api/boilerplate/request_response.rs

@@ -50,15 +50,28 @@ impl ResponseMsg for super::SupplyKeypairResponse {
     type RequestMsg = super::SupplyKeypairRequest;
 }
 
+impl RequestMsg for super::AddListenSocketRequest {
+    type ResponseMsg = super::AddListenSocketResponse;
+}
+
+impl ResponseMsg for super::AddListenSocketResponse {
+    type RequestMsg = super::AddListenSocketRequest;
+}
+
 pub type PingPair<B1, B2> = (Ref<B1, PingRequest>, Ref<B2, PingResponse>);
 pub type SupplyKeypairPair<B1, B2> = (
     Ref<B1, super::SupplyKeypairRequest>,
     Ref<B2, super::SupplyKeypairResponse>,
 );
+pub type AddListenSocketPair<B1, B2> = (
+    Ref<B1, super::AddListenSocketRequest>,
+    Ref<B2, super::AddListenSocketResponse>,
+);
 
 pub enum RequestResponsePair<B1, B2> {
     Ping(PingPair<B1, B2>),
     SupplyKeypair(SupplyKeypairPair<B1, B2>),
+    AddListenSocket(AddListenSocketPair<B1, B2>),
 }
 
 impl<B1, B2> From<PingPair<B1, B2>> for RequestResponsePair<B1, B2> {
@@ -73,6 +86,12 @@ impl<B1, B2> From<SupplyKeypairPair<B1, B2>> for RequestResponsePair<B1, B2> {
     }
 }
 
+impl<B1, B2> From<AddListenSocketPair<B1, B2>> for RequestResponsePair<B1, B2> {
+    fn from(v: AddListenSocketPair<B1, B2>) -> Self {
+        RequestResponsePair::AddListenSocket(v)
+    }
+}
+
 impl<B1, B2> RequestResponsePair<B1, B2>
 where
     B1: ByteSlice,
@@ -90,6 +109,11 @@ where
                 let res = ResponseRef::SupplyKeypair(res.emancipate());
                 (req, res)
             }
+            Self::AddListenSocket((req, res)) => {
+                let req = RequestRef::AddListenSocket(req.emancipate());
+                let res = ResponseRef::AddListenSocket(res.emancipate());
+                (req, res)
+            }
         }
     }
 
@@ -119,6 +143,11 @@ where
                 let res = ResponseRef::SupplyKeypair(res.emancipate_mut());
                 (req, res)
             }
+            Self::AddListenSocket((req, res)) => {
+                let req = RequestRef::AddListenSocket(req.emancipate_mut());
+                let res = ResponseRef::AddListenSocket(res.emancipate_mut());
+                (req, res)
+            }
         }
     }
 

rosenpass/src/api/boilerplate/response_ref.rs

@@ -27,6 +27,7 @@ impl<B: ByteSlice> ResponseRef<B> {
         match self {
             Self::Ping(_) => ResponseMsgType::Ping,
             Self::SupplyKeypair(_) => ResponseMsgType::SupplyKeypair,
+            Self::AddListenSocket(_) => ResponseMsgType::AddListenSocket,
         }
     }
 }
@@ -43,6 +44,12 @@ impl<B> From<Ref<B, super::SupplyKeypairResponse>> for ResponseRef<B> {
     }
 }
 
+impl<B> From<Ref<B, super::AddListenSocketResponse>> for ResponseRef<B> {
+    fn from(v: Ref<B, super::AddListenSocketResponse>) -> Self {
+        Self::AddListenSocket(v)
+    }
+}
+
 impl<B: ByteSlice> ResponseRefMaker<B> {
     fn new(buf: B) -> anyhow::Result<Self> {
         let msg_type = buf.deref().response_msg_type_from_prefix()?;
@@ -59,6 +66,9 @@ impl<B: ByteSlice> ResponseRefMaker<B> {
             ResponseMsgType::SupplyKeypair => {
                 ResponseRef::SupplyKeypair(self.buf.supply_keypair_response()?)
             }
+            ResponseMsgType::AddListenSocket => {
+                ResponseRef::AddListenSocket(self.buf.add_listen_socket_response()?)
+            }
         })
     }
 
@@ -94,6 +104,7 @@ impl<B: ByteSlice> ResponseRefMaker<B> {
 pub enum ResponseRef<B> {
     Ping(Ref<B, PingResponse>),
     SupplyKeypair(Ref<B, super::SupplyKeypairResponse>),
+    AddListenSocket(Ref<B, super::AddListenSocketResponse>),
 }
 
 impl<B> ResponseRef<B>
@@ -104,6 +115,7 @@ where
         match self {
             Self::Ping(r) => r.bytes(),
             Self::SupplyKeypair(r) => r.bytes(),
+            Self::AddListenSocket(r) => r.bytes(),
         }
     }
 }
@@ -116,6 +128,7 @@ where
         match self {
             Self::Ping(r) => r.bytes_mut(),
             Self::SupplyKeypair(r) => r.bytes_mut(),
+            Self::AddListenSocket(r) => r.bytes_mut(),
         }
     }
 }

rosenpass/src/api/boilerplate/server.rs

@@ -17,6 +17,13 @@ pub trait Server {
         res: &mut super::SupplyKeypairResponse,
     ) -> anyhow::Result<()>;
 
+    fn add_listen_socket(
+        &mut self,
+        req: &super::AddListenSocketRequest,
+        req_fds: &mut VecDeque<OwnedFd>,
+        res: &mut super::AddListenSocketResponse,
+    ) -> anyhow::Result<()>;
+
     fn dispatch<ReqBuf, ResBuf>(
         &mut self,
         p: &mut RequestResponsePair<ReqBuf, ResBuf>,
@@ -31,6 +38,9 @@ pub trait Server {
             RequestResponsePair::SupplyKeypair((req, res)) => {
                 self.supply_keypair(req, req_fds, res)
             }
+            RequestResponsePair::AddListenSocket((req, res)) => {
+                self.add_listen_socket(req, req_fds, res)
+            }
         }
     }
 
@@ -57,6 +67,11 @@ pub trait Server {
                 res.init();
                 RequestResponsePair::SupplyKeypair((req, res))
             }
+            RequestRef::AddListenSocket(req) => {
+                let mut res = res.add_listen_socket_response_from_prefix()?;
+                res.init();
+                RequestResponsePair::AddListenSocket((req, res))
+            }
         };
         self.dispatch(&mut pair, req_fds)?;
 

rosenpass/src/bin/gen-ipc-msg-types.rs

@@ -78,6 +78,8 @@ fn main() -> Result<()> {
                 Tree::Leaf("Ping Response".to_owned()),
                 Tree::Leaf("Supply Keypair Request".to_owned()),
                 Tree::Leaf("Supply Keypair Response".to_owned()),
+                Tree::Leaf("Add Listen Socket Request".to_owned()),
+                Tree::Leaf("Add Listen Socket Response".to_owned()),
             ],
         )],
     );

rosenpass/tests/api-integration-tests-api-setup.rs

@@ -1,6 +1,5 @@
 use std::{
     io::{BufRead, BufReader},
-    net::ToSocketAddrs,
     os::unix::net::UnixStream,
     process::Stdio,
     thread::sleep,
@@ -8,19 +7,21 @@ use std::{
 };
 
 use anyhow::{bail, Context};
-use rosenpass::api::{self, supply_keypair_response_status};
+use rosenpass::api::{self, add_listen_socket_response_status, supply_keypair_response_status};
 use rosenpass_util::{
     file::LoadValueB64,
     length_prefix_encoding::{decoder::LengthPrefixDecoder, encoder::LengthPrefixEncoder},
+    mio::WriteWithFileDescriptors,
+    zerocopy::ZerocopySliceExt,
 };
-use rosenpass_util::{mio::WriteWithFileDescriptors, zerocopy::ZerocopySliceExt};
+use rustix::fd::AsFd;
 use tempfile::TempDir;
 use zerocopy::AsBytes;
 
 use rosenpass::protocol::SymKey;
 
 #[test]
-fn api_integration_test() -> anyhow::Result<()> {
+fn api_integration_api_setup() -> anyhow::Result<()> {
     rosenpass_secret_memory::policy::secret_policy_use_only_malloc_secrets();
 
     let dir = TempDir::with_prefix("rosenpass-api-integration-test")?;
@@ -33,17 +34,20 @@ fn api_integration_test() -> anyhow::Result<()> {
         }}
     }
 
-    let peer_a_endpoint = "[::1]:61424";
+    let peer_a_endpoint = "[::1]:0";
     let peer_a_osk = tempfile!("a.osk");
     let peer_b_osk = tempfile!("b.osk");
 
+    let peer_a_listen = std::net::UdpSocket::bind(peer_a_endpoint)?;
+    let peer_a_endpoint = format!("{}", peer_a_listen.local_addr()?);
+
     use rosenpass::config;
 
     let peer_a_keypair = config::Keypair::new(tempfile!("a.pk"), tempfile!("a.sk"));
     let peer_a = config::Rosenpass {
         config_file_path: tempfile!("a.config"),
-        keypair: Some(peer_a_keypair.clone()),
+        keypair: None,
-        listen: peer_a_endpoint.to_socket_addrs()?.collect(), // TODO: This could collide by accident
+        listen: vec![], // TODO: This could collide by accident
         verbosity: config::Verbosity::Verbose,
         api: api::config::ApiConfig {
             listen_path: vec![tempfile!("a.sock")],
@@ -62,7 +66,7 @@ fn api_integration_test() -> anyhow::Result<()> {
     let peer_b_keypair = config::Keypair::new(tempfile!("b.pk"), tempfile!("b.sk"));
     let peer_b = config::Rosenpass {
         config_file_path: tempfile!("b.config"),
-        keypair: None,
+        keypair: Some(peer_b_keypair.clone()),
         listen: vec![],
         verbosity: config::Verbosity::Verbose,
         api: api::config::ApiConfig {
@@ -118,7 +122,7 @@ fn api_integration_test() -> anyhow::Result<()> {
     let mut out_b = BufReader::new(proc_b.stdout.context("")?).lines();
 
     // Now connect to the peers
-    let api_path = peer_b.api.listen_path[0].as_path();
+    let api_path = peer_a.api.listen_path[0].as_path();
 
     // Wait for the socket to be created
     let attempt = 0;
@@ -132,11 +136,34 @@ fn api_integration_test() -> anyhow::Result<()> {
 
     let api = UnixStream::connect(api_path)?;
 
+    // Send AddListenSocket request
+    {
+        let fd = peer_a_listen.as_fd();
+
+        let mut fds = vec![&fd].into();
+        let mut api = WriteWithFileDescriptors::<UnixStream, _, _, _>::new(&api, &mut fds);
+        LengthPrefixEncoder::from_message(api::AddListenSocketRequest::new().as_bytes())
+            .write_all_to_stdio(&mut api)?;
+        assert!(fds.is_empty(), "Failed to write all file descriptors");
+        std::mem::forget(peer_a_listen);
+    }
+
+    // Read response
+    {
+        let mut decoder = LengthPrefixDecoder::new([0u8; api::MAX_RESPONSE_LEN]);
+        let res = decoder.read_all_from_stdio(&api)?;
+        let res = res.zk_parse::<api::AddListenSocketResponse>()?;
+        assert_eq!(
+            *res,
+            api::AddListenSocketResponse::new(add_listen_socket_response_status::OK)
+        );
+    }
+
     // Send SupplyKeypairRequest
     {
         use rustix::fs::{open, Mode, OFlags};
-        let sk = open(peer_b_keypair.secret_key, OFlags::RDONLY, Mode::empty())?;
+        let sk = open(peer_a_keypair.secret_key, OFlags::RDONLY, Mode::empty())?;
-        let pk = open(peer_b_keypair.public_key, OFlags::RDONLY, Mode::empty())?;
+        let pk = open(peer_a_keypair.public_key, OFlags::RDONLY, Mode::empty())?;
 
         let mut fds = vec![&sk, &pk].into();
         let mut api = WriteWithFileDescriptors::<UnixStream, _, _, _>::new(&api, &mut fds);
@@ -147,7 +174,6 @@ fn api_integration_test() -> anyhow::Result<()> {
 
     // Read response
     {
-        //sleep(Duration::from_secs(10));
         let mut decoder = LengthPrefixDecoder::new([0u8; api::MAX_RESPONSE_LEN]);
         let res = decoder.read_all_from_stdio(api)?;
         let res = res.zk_parse::<api::SupplyKeypairResponse>()?;

util/src/controlflow.rs

@@ -7,6 +7,20 @@ macro_rules! repeat {
     };
 }
 
+#[macro_export]
+macro_rules! return_unless {
+    ($cond:expr) => {
+        if !($cond) {
+            return;
+        }
+    };
+    ($cond:expr, $val:expr) => {
+        if !($cond) {
+            return $val;
+        }
+    };
+}
+
 #[macro_export]
 macro_rules! return_if {
     ($cond:expr) => {

util/src/fd.rs

@@ -1,12 +1,10 @@
+use anyhow::bail;
 use rustix::{
     fd::{AsFd, BorrowedFd, FromRawFd, OwnedFd, RawFd},
     io::fcntl_dupfd_cloexec,
 };
 
-#[cfg(target_os = "linux")]
+use crate::{mem::Forgetting, result::OkExt};
-use rustix::io::DupFlags;
-
-use crate::mem::Forgetting;
 
 /// Prepare a file descriptor for use in Rust code.
 ///
@@ -51,7 +49,7 @@ pub fn clone_fd_cloexec<Fd: AsFd>(fd: Fd) -> rustix::io::Result<OwnedFd> {
 
 #[cfg(target_os = "linux")]
 pub fn clone_fd_to_cloexec<Fd: AsFd>(fd: Fd, new: &mut OwnedFd) -> rustix::io::Result<()> {
-    use rustix::io::dup3;
+    use rustix::io::{dup3, DupFlags};
     dup3(fd, new, DupFlags::CLOEXEC)
 }
 
@@ -111,6 +109,85 @@ impl<Fd: AsFd> std::io::Write for FdIo<Fd> {
     }
 }
 
+pub trait StatExt {
+    fn is_socket(&self) -> bool;
+}
+
+impl StatExt for rustix::fs::Stat {
+    fn is_socket(&self) -> bool {
+        use rustix::fs::FileType;
+        let ft = FileType::from_raw_mode(self.st_mode);
+        matches!(ft, FileType::Socket)
+    }
+}
+
+pub trait TryStatExt {
+    type Error;
+    fn is_socket(&self) -> Result<bool, Self::Error>;
+}
+
+impl<T> TryStatExt for T
+where
+    T: AsFd,
+{
+    type Error = rustix::io::Errno;
+
+    fn is_socket(&self) -> Result<bool, Self::Error> {
+        rustix::fs::fstat(self)?.is_socket().ok()
+    }
+}
+
+pub trait GetSocketType {
+    type Error;
+    fn socket_type(&self) -> Result<rustix::net::SocketType, Self::Error>;
+    fn is_datagram_socket(&self) -> Result<bool, Self::Error> {
+        use rustix::net::SocketType;
+        matches!(self.socket_type()?, SocketType::DGRAM).ok()
+    }
+}
+
+impl<T> GetSocketType for T
+where
+    T: AsFd,
+{
+    type Error = rustix::io::Errno;
+
+    fn socket_type(&self) -> Result<rustix::net::SocketType, Self::Error> {
+        rustix::net::sockopt::get_socket_type(self)
+    }
+}
+
+#[cfg(target_os = "linux")]
+pub trait GetSocketProtocol {
+    fn socket_protocol(&self) -> Result<Option<rustix::net::Protocol>, rustix::io::Errno>;
+    fn is_udp_socket(&self) -> Result<bool, rustix::io::Errno> {
+        self.socket_protocol()?
+            .map(|p| p == rustix::net::ipproto::UDP)
+            .unwrap_or(false)
+            .ok()
+    }
+    fn demand_udp_socket(&self) -> anyhow::Result<()> {
+        match self.socket_protocol() {
+            Ok(Some(rustix::net::ipproto::UDP)) => Ok(()),
+            Ok(Some(other_proto)) => {
+                bail!("Not a udp socket, instead socket protocol is: {other_proto:?}")
+            }
+            Ok(None) => bail!("getsockopt() returned empty value"),
+            Err(errno) => Err(errno.into_stdio_err())?,
+        }
+    }
+}
+
+#[cfg(target_os = "linux")]
+impl<T> GetSocketProtocol for T
+where
+    T: AsFd,
+{
+    fn socket_protocol(&self) -> Result<Option<rustix::net::Protocol>, rustix::io::Errno> {
+        rustix::net::sockopt::get_socket_protocol(self)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

util/src/mio/mio.rs

@@ -1,7 +1,7 @@
 use mio::net::{UnixListener, UnixStream};
-use rustix::fd::RawFd;
+use rustix::fd::{OwnedFd, RawFd};
 
-use crate::fd::claim_fd;
+use crate::{fd::claim_fd, result::OkExt};
 
 pub mod interest {
     use mio::Interest;
@@ -25,15 +25,20 @@ impl UnixListenerExt for UnixListener {
 }
 
 pub trait UnixStreamExt: Sized {
+    fn from_fd(fd: OwnedFd) -> anyhow::Result<Self>;
     fn claim_fd(fd: RawFd) -> anyhow::Result<Self>;
 }
 
 impl UnixStreamExt for UnixStream {
-    fn claim_fd(fd: RawFd) -> anyhow::Result<Self> {
+    fn from_fd(fd: OwnedFd) -> anyhow::Result<Self> {
         use std::os::unix::net::UnixStream as StdUnixStream;
 
-        let sock = StdUnixStream::from(claim_fd(fd)?);
+        let sock = StdUnixStream::from(fd);
         sock.set_nonblocking(true)?;
-        Ok(UnixStream::from_std(sock))
+        UnixStream::from_std(sock).ok()
+    }
+
+    fn claim_fd(fd: RawFd) -> anyhow::Result<Self> {
+        Self::from_fd(claim_fd(fd)?)
     }
 }