Merge branch 'main' into dependency-chore

* fixme/correct-type

* added newsfragment and test

docs/examples.mDNS.rst

@@ -0,0 +1,64 @@
+mDNS Peer Discovery Example
+===========================
+
+This example demonstrates how to use mDNS (Multicast DNS) for peer discovery in py-libp2p.
+
+Prerequisites
+-------------
+
+First, ensure you have py-libp2p installed and your environment is activated:
+
+.. code-block:: console
+
+    $ python -m pip install libp2p
+
+Running the Example
+-------------------
+
+The mDNS demo script allows you to discover peers on your local network using mDNS. To start a peer, run:
+
+.. code-block:: console
+
+    $ mdns-demo
+
+You should see output similar to:
+
+.. code-block:: console
+
+    Run this from another console to start another peer on a different port:
+
+    python mdns-demo -p <ANOTHER_PORT>
+
+    Waiting for mDNS peer discovery events...
+
+    2025-06-20 23:28:12,052 - libp2p.example.discovery.mdns - INFO - Starting peer Discovery
+
+To discover peers, open another terminal and run the same command with a different port:
+
+.. code-block:: console
+
+    $ python mdns-demo -p 9001
+
+You should see output indicating that a new peer has been discovered:
+
+.. code-block:: console
+
+    Run this from the same folder in another console to start another peer on a different port:
+
+    python mdns-demo -p <ANOTHER_PORT>
+
+    Waiting for mDNS peer discovery events...
+
+    2025-06-20 23:43:43,786 - libp2p.example.discovery.mdns - INFO - Starting peer Discovery
+    2025-06-20 23:43:43,790 - libp2p.example.discovery.mdns - INFO - Discovered: 16Uiu2HAmGxy5NdQEjZWtrYUMrzdp3Syvg7MB2E5Lx8weA9DanYxj
+
+When a new peer is discovered, its peer ID will be printed in the console output.
+
+How it Works
+------------
+
+- Each node advertises itself on the local network using mDNS.
+- When a new peer is discovered, the handler prints its peer ID.
+- This is useful for local peer discovery without requiring a DHT or bootstrap nodes.
+
+You can modify the script to perform additional actions when peers are discovered, such as opening streams or exchanging messages.

docs/examples.rst

@@ -13,3 +13,4 @@ Examples
    examples.pubsub
    examples.circuit_relay
    examples.kademlia
+   examples.mDNS

docs/libp2p.discovery.events.rst

@@ -0,0 +1,21 @@
+libp2p.discovery.events package
+===============================
+
+Submodules
+----------
+
+libp2p.discovery.events.peerDiscovery module
+--------------------------------------------
+
+.. automodule:: libp2p.discovery.events.peerDiscovery
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery.events
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.discovery.mdns.rst

@@ -0,0 +1,45 @@
+libp2p.discovery.mdns package
+=============================
+
+Submodules
+----------
+
+libp2p.discovery.mdns.broadcaster module
+----------------------------------------
+
+.. automodule:: libp2p.discovery.mdns.broadcaster
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.listener module
+-------------------------------------
+
+.. automodule:: libp2p.discovery.mdns.listener
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.mdns module
+---------------------------------
+
+.. automodule:: libp2p.discovery.mdns.mdns
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.utils module
+----------------------------------
+
+.. automodule:: libp2p.discovery.mdns.utils
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery.mdns
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.discovery.rst

@@ -0,0 +1,22 @@
+libp2p.discovery package
+========================
+
+Subpackages
+-----------
+
+.. toctree::
+   :maxdepth: 4
+
+   libp2p.discovery.events
+   libp2p.discovery.mdns
+
+Submodules
+----------
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.rst

@@ -8,6 +8,7 @@ Subpackages
    :maxdepth: 4
 
    libp2p.crypto
+   libp2p.discovery
    libp2p.host
    libp2p.identity
    libp2p.io

docs/release_notes.rst

@@ -3,6 +3,65 @@ Release Notes
 
 .. towncrier release notes start
 
+py-libp2p v0.2.9 (2025-07-09)
+-----------------------------
+
+Breaking Changes
+~~~~~~~~~~~~~~~~
+
+- Reordered the arguments to ``upgrade_security`` to place ``is_initiator`` before ``peer_id``, and made ``peer_id`` optional.
+  This allows the method to reflect the fact that peer identity is not required for inbound connections. (`#681 <https://github.com/libp2p/py-libp2p/issues/681>`__)
+
+
+Bugfixes
+~~~~~~~~
+
+- Add timeout wrappers in:
+  1. ``multiselect.py``: ``negotiate`` function
+  2. ``multiselect_client.py``: ``select_one_of`` , ``query_multistream_command`` functions
+  to prevent indefinite hangs when a remote peer does not respond. (`#696 <https://github.com/libp2p/py-libp2p/issues/696>`__)
+- Align stream creation logic with yamux specification (`#701 <https://github.com/libp2p/py-libp2p/issues/701>`__)
+- Fixed an issue in ``Pubsub`` where async validators were not handled reliably under concurrency. Now uses a safe aggregator list for consistent behavior. (`#702 <https://github.com/libp2p/py-libp2p/issues/702>`__)
+
+
+Features
+~~~~~~~~
+
+- Added support for ``Kademlia DHT`` in py-libp2p. (`#579 <https://github.com/libp2p/py-libp2p/issues/579>`__)
+- Limit concurrency in ``push_identify_to_peers`` to prevent resource congestion under high peer counts. (`#621 <https://github.com/libp2p/py-libp2p/issues/621>`__)
+- Store public key and peer ID in peerstore during handshake
+
+  Modified the InsecureTransport class to accept an optional peerstore parameter and updated the handshake process to store the received public key and peer ID in the peerstore when available.
+
+  Added test cases to verify:
+  1. The peerstore remains unchanged when handshake fails due to peer ID mismatch
+  2. The handshake correctly adds a public key to a peer ID that already exists in the peerstore but doesn't have a public key yet (`#631 <https://github.com/libp2p/py-libp2p/issues/631>`__)
+- Fixed several flow-control and concurrency issues in the ``YamuxStream`` class. Previously, stress-testing revealed that transferring data over ``DEFAULT_WINDOW_SIZE`` would break the stream due to inconsistent window update handling and lock management. The fixes include:
+
+  - Removed sending of window updates during writes to maintain correct flow-control.
+  - Added proper timeout handling when releasing and acquiring locks to prevent concurrency errors.
+  - Corrected the ``read`` function to properly handle window updates for both ``read_until_EOF`` and ``read_n_bytes``.
+  - Added event logging at ``send_window_updates`` and ``waiting_for_window_updates`` for better observability. (`#639 <https://github.com/libp2p/py-libp2p/issues/639>`__)
+- Added support for ``Multicast DNS`` in py-libp2p (`#649 <https://github.com/libp2p/py-libp2p/issues/649>`__)
+- Optimized pubsub publishing to send multiple topics in a single message instead of separate messages per topic. (`#685 <https://github.com/libp2p/py-libp2p/issues/685>`__)
+- Optimized pubsub message writing by implementing a write_msg() method that uses pre-allocated buffers and single write operations, improving performance by eliminating separate varint prefix encoding and write operations in FloodSub and GossipSub. (`#687 <https://github.com/libp2p/py-libp2p/issues/687>`__)
+- Added peer exchange and backoff logic as part of Gossipsub v1.1 upgrade (`#690 <https://github.com/libp2p/py-libp2p/issues/690>`__)
+
+
+Internal Changes - for py-libp2p Contributors
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Added sparse connect utility function to pubsub test utilities for creating test networks with configurable connectivity. (`#679 <https://github.com/libp2p/py-libp2p/issues/679>`__)
+- Added comprehensive tests for pubsub connection utility functions to verify degree limits are enforced, excess peers are handled correctly, and edge cases (degree=0, negative values, empty lists) are managed gracefully. (`#707 <https://github.com/libp2p/py-libp2p/issues/707>`__)
+- Added extra tests for identify push concurrency cap under high peer load (`#708 <https://github.com/libp2p/py-libp2p/issues/708>`__)
+
+
+Miscellaneous Changes
+~~~~~~~~~~~~~~~~~~~~~
+
+- `#678 <https://github.com/libp2p/py-libp2p/issues/678>`__, `#684 <https://github.com/libp2p/py-libp2p/issues/684>`__
+
+
 py-libp2p v0.2.8 (2025-06-10)
 -----------------------------
 

examples/mDNS/mDNS.py

@@ -0,0 +1,74 @@
+import argparse
+import logging
+import secrets
+
+import multiaddr
+import trio
+
+from libp2p import (
+    new_host,
+)
+from libp2p.abc import PeerInfo
+from libp2p.crypto.secp256k1 import (
+    create_new_key_pair,
+)
+from libp2p.discovery.events.peerDiscovery import peerDiscovery
+
+logger = logging.getLogger("libp2p.discovery.mdns")
+logger.setLevel(logging.INFO)
+handler = logging.StreamHandler()
+handler.setFormatter(
+    logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
+)
+logger.addHandler(handler)
+
+# Set root logger to DEBUG to capture all logs from dependencies
+logging.getLogger().setLevel(logging.DEBUG)
+
+
+def onPeerDiscovery(peerinfo: PeerInfo):
+    logger.info(f"Discovered: {peerinfo.peer_id}")
+
+
+async def run(port: int) -> None:
+    secret = secrets.token_bytes(32)
+    key_pair = create_new_key_pair(secret)
+    listen_addr = multiaddr.Multiaddr(f"/ip4/0.0.0.0/tcp/{port}")
+
+    peerDiscovery.register_peer_discovered_handler(onPeerDiscovery)
+
+    print(
+        "Run this from the same folder in another console to "
+        "start another peer on a different port:\n\n"
+        "mdns-demo -p <ANOTHER_PORT>\n"
+    )
+    print("Waiting for mDNS peer discovery events...\n")
+
+    logger.info("Starting peer Discovery")
+    host = new_host(key_pair=key_pair, enable_mDNS=True)
+    async with host.run(listen_addrs=[listen_addr]):
+        await trio.sleep_forever()
+
+
+def main() -> None:
+    description = """
+    This program demonstrates mDNS peer discovery using libp2p.
+    To use it, run 'mdns-demo -p <PORT>', where <PORT> is the port number.
+    Start multiple peers on different ports to see discovery in action.
+    """
+    parser = argparse.ArgumentParser(description=description)
+    parser.add_argument("-p", "--port", default=0, type=int, help="source port number")
+    parser.add_argument(
+        "-v", "--verbose", action="store_true", help="Enable verbose output"
+    )
+    args = parser.parse_args()
+    if args.verbose:
+        logger.setLevel(logging.DEBUG)
+    try:
+        trio.run(run, args.port)
+    except KeyboardInterrupt:
+        logger.info("Exiting...")
+
+
+if __name__ == "__main__":
+    main()

libp2p/__init__.py

@@ -32,6 +32,9 @@ from libp2p.custom_types import (
     TProtocol,
     TSecurityOptions,
 )
+from libp2p.discovery.mdns.mdns import (
+    MDNSDiscovery,
+)
 from libp2p.host.basic_host import (
     BasicHost,
 )
@@ -81,6 +84,8 @@ DEFAULT_MUXER = "YAMUX"
 # Multiplexer options
 MUXER_YAMUX = "YAMUX"
 MUXER_MPLEX = "MPLEX"
+DEFAULT_NEGOTIATE_TIMEOUT = 5
+
 
 
 def set_default_muxer(muxer_name: Literal["YAMUX", "MPLEX"]) -> None:
@@ -245,6 +250,8 @@ def new_host(
     disc_opt: IPeerRouting | None = None,
     muxer_preference: Literal["YAMUX", "MPLEX"] | None = None,
     listen_addrs: Sequence[multiaddr.Multiaddr] | None = None,
+    enable_mDNS: bool = False,
+    negotiate_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
 ) -> IHost:
     """
     Create a new libp2p host based on the given parameters.
@@ -256,6 +263,7 @@ def new_host(
     :param disc_opt: optional discovery
     :param muxer_preference: optional explicit muxer preference
     :param listen_addrs: optional list of multiaddrs to listen on
+    :param enable_mDNS: whether to enable mDNS discovery
     :return: return a host instance
     """
     swarm = new_swarm(
@@ -268,8 +276,7 @@ def new_host(
     )
 
     if disc_opt is not None:
-        return RoutedHost(swarm, disc_opt)
-    return BasicHost(swarm)
-
+        return RoutedHost(swarm, disc_opt, enable_mDNS)
+    return BasicHost(network=swarm,enable_mDNS=enable_mDNS , negotitate_timeout=negotiate_timeout)
 
 __version__ = __version("libp2p")

libp2p/abc.py

@@ -50,6 +50,11 @@ if TYPE_CHECKING:
         Pubsub,
     )
 
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from libp2p.protocol_muxer.multiselect import Multiselect
+
 from libp2p.pubsub.pb import (
     rpc_pb2,
 )
@@ -385,6 +390,18 @@ class IPeerMetadata(ABC):
         :raises Exception: If the operation is unsuccessful.
         """
 
+    @abstractmethod
+    def clear_metadata(self, peer_id: ID) -> None:
+        """
+        Remove all stored metadata for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose metadata are to be removed.
+
+        """
+
 
 # -------------------------- addrbook interface.py --------------------------
 
@@ -476,10 +493,272 @@ class IAddrBook(ABC):
         """
 
 
+# -------------------------- keybook interface.py --------------------------
+
+
+class IKeyBook(ABC):
+    """
+    Interface for an key book.
+
+    Provides methods for managing cryptographic keys.
+    """
+
+    @abstractmethod
+    def pubkey(self, peer_id: ID) -> PublicKey:
+        """
+        Returns the public key of the specified peer
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose public key is to be returned.
+
+        """
+
+    @abstractmethod
+    def privkey(self, peer_id: ID) -> PrivateKey:
+        """
+        Returns the private key of the specified peer
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose private key is to be returned.
+
+        """
+
+    @abstractmethod
+    def add_pubkey(self, peer_id: ID, pubkey: PublicKey) -> None:
+        """
+        Adds the public key for a specified peer
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose public key is to be added
+        pubkey: PublicKey
+            The public key of the peer
+
+        """
+
+    @abstractmethod
+    def add_privkey(self, peer_id: ID, privkey: PrivateKey) -> None:
+        """
+        Adds the private key for a specified peer
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose private key is to be added
+        privkey: PrivateKey
+            The private key of the peer
+
+        """
+
+    @abstractmethod
+    def add_key_pair(self, peer_id: ID, key_pair: KeyPair) -> None:
+        """
+        Adds the key pair for a specified peer
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose key pair is to be added
+        key_pair: KeyPair
+            The key pair of the peer
+
+        """
+
+    @abstractmethod
+    def peer_with_keys(self) -> list[ID]:
+        """Returns all the peer IDs stored in the AddrBook"""
+
+    @abstractmethod
+    def clear_keydata(self, peer_id: ID) -> None:
+        """
+        Remove all stored keydata for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose keys are to be removed.
+
+        """
+
+
+# -------------------------- metrics interface.py --------------------------
+
+
+class IMetrics(ABC):
+    """
+    Interface for metrics of peer interaction.
+
+    Provides methods for managing the metrics.
+    """
+
+    @abstractmethod
+    def record_latency(self, peer_id: ID, RTT: float) -> None:
+        """
+        Records a new round-trip time (RTT) latency value for the specified peer
+        using Exponentially Weighted Moving Average (EWMA).
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer for which latency is being recorded.
+
+        RTT : float
+            The round-trip time latency value to record.
+
+        """
+
+    @abstractmethod
+    def latency_EWMA(self, peer_id: ID) -> float:
+        """
+        Returns the current latency value for the specified peer using
+        Exponentially Weighted Moving Average (EWMA).
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose latency EWMA is to be returned.
+
+        """
+
+    @abstractmethod
+    def clear_metrics(self, peer_id: ID) -> None:
+        """
+        Clears the stored latency metrics for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose latency metrics are to be cleared.
+
+        """
+
+
+# -------------------------- protobook interface.py --------------------------
+
+
+class IProtoBook(ABC):
+    """
+    Interface for a protocol book.
+
+    Provides methods for managing the list of supported protocols.
+    """
+
+    @abstractmethod
+    def get_protocols(self, peer_id: ID) -> list[str]:
+        """
+        Returns the list of protocols associated with the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose supported protocols are to be returned.
+
+        """
+
+    @abstractmethod
+    def add_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Adds the given protocols to the specified peer's protocol list.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer to which protocols will be added.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to add.
+
+        """
+
+    @abstractmethod
+    def set_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Replaces the existing protocols of the specified peer with the given list.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose protocols are to be set.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to assign.
+
+        """
+
+    @abstractmethod
+    def remove_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Removes the specified protocols from the peer's protocol list.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer from which protocols will be removed.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to remove.
+
+        """
+
+    @abstractmethod
+    def supports_protocols(self, peer_id: ID, protocols: Sequence[str]) -> list[str]:
+        """
+        Returns the list of protocols from the input sequence that the peer supports.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer to check for protocol support.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to check against the peer's
+            supported protocols.
+
+        """
+
+    @abstractmethod
+    def first_supported_protocol(self, peer_id: ID, protocols: Sequence[str]) -> str:
+        """
+        Returns the first protocol from the input list that the peer supports.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer to check for supported protocols.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to check.
+
+        Returns
+        -------
+        str
+            The first matching protocol string, or an empty string
+            if none are supported.
+
+        """
+
+    @abstractmethod
+    def clear_protocol_data(self, peer_id: ID) -> None:
+        """
+        Clears all protocol data associated with the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose protocol data will be cleared.
+
+        """
+
+
 # -------------------------- peerstore interface.py --------------------------
 
 
-class IPeerStore(IAddrBook, IPeerMetadata):
+class IPeerStore(IPeerMetadata, IAddrBook, IKeyBook, IMetrics, IProtoBook):
     """
     Interface for a peer store.
 
@@ -487,85 +766,7 @@ class IPeerStore(IAddrBook, IPeerMetadata):
     management, protocol handling, and key storage.
     """
 
-    @abstractmethod
-    def peer_info(self, peer_id: ID) -> PeerInfo:
-        """
-        Retrieve the peer information for the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-
-        Returns
-        -------
-        PeerInfo
-            The peer information object for the given peer.
-
-        """
-
-    @abstractmethod
-    def get_protocols(self, peer_id: ID) -> list[str]:
-        """
-        Retrieve the protocols associated with the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-
-        Returns
-        -------
-        list[str]
-            A list of protocol identifiers.
-
-        Raises
-        ------
-        PeerStoreError
-            If the peer ID is not found.
-
-        """
-
-    @abstractmethod
-    def add_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
-        """
-        Add additional protocols for the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-        protocols : Sequence[str]
-            The protocols to add.
-
-        """
-
-    @abstractmethod
-    def set_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
-        """
-        Set the protocols for the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-        protocols : Sequence[str]
-            The protocols to set.
-
-        """
-
-    @abstractmethod
-    def peer_ids(self) -> list[ID]:
-        """
-        Retrieve all peer identifiers stored in the peer store.
-
-        Returns
-        -------
-        list[ID]
-            A list of all peer IDs in the store.
-
-        """
-
+    # -------METADATA---------
     @abstractmethod
     def get(self, peer_id: ID, key: str) -> Any:
         """
@@ -606,6 +807,19 @@ class IPeerStore(IAddrBook, IPeerMetadata):
 
         """
 
+    @abstractmethod
+    def clear_metadata(self, peer_id: ID) -> None:
+        """
+        Clears the stored latency metrics for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose latency metrics are to be cleared.
+
+        """
+
+    # --------ADDR-BOOK---------
     @abstractmethod
     def add_addr(self, peer_id: ID, addr: Multiaddr, ttl: int) -> None:
         """
@@ -679,25 +893,7 @@ class IPeerStore(IAddrBook, IPeerMetadata):
 
         """
 
-    @abstractmethod
-    def add_pubkey(self, peer_id: ID, pubkey: PublicKey) -> None:
-        """
-        Add a public key for the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-        pubkey : PublicKey
-            The public key to add.
-
-        Raises
-        ------
-        PeerStoreError
-            If the peer already has a public key set.
-
-        """
-
+    # --------KEY-BOOK----------
     @abstractmethod
     def pubkey(self, peer_id: ID) -> PublicKey:
         """
@@ -720,25 +916,6 @@ class IPeerStore(IAddrBook, IPeerMetadata):
 
         """
 
-    @abstractmethod
-    def add_privkey(self, peer_id: ID, privkey: PrivateKey) -> None:
-        """
-        Add a private key for the specified peer.
-
-        Parameters
-        ----------
-        peer_id : ID
-            The identifier of the peer.
-        privkey : PrivateKey
-            The private key to add.
-
-        Raises
-        ------
-        PeerStoreError
-            If the peer already has a private key set.
-
-        """
-
     @abstractmethod
     def privkey(self, peer_id: ID) -> PrivateKey:
         """
@@ -761,6 +938,44 @@ class IPeerStore(IAddrBook, IPeerMetadata):
 
         """
 
+    @abstractmethod
+    def add_pubkey(self, peer_id: ID, pubkey: PublicKey) -> None:
+        """
+        Add a public key for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+        pubkey : PublicKey
+            The public key to add.
+
+        Raises
+        ------
+        PeerStoreError
+            If the peer already has a public key set.
+
+        """
+
+    @abstractmethod
+    def add_privkey(self, peer_id: ID, privkey: PrivateKey) -> None:
+        """
+        Add a private key for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+        privkey : PrivateKey
+            The private key to add.
+
+        Raises
+        ------
+        PeerStoreError
+            If the peer already has a private key set.
+
+        """
+
     @abstractmethod
     def add_key_pair(self, peer_id: ID, key_pair: KeyPair) -> None:
         """
@@ -780,6 +995,213 @@ class IPeerStore(IAddrBook, IPeerMetadata):
 
         """
 
+    @abstractmethod
+    def peer_with_keys(self) -> list[ID]:
+        """Returns all the peer IDs stored in the AddrBook"""
+
+    @abstractmethod
+    def clear_keydata(self, peer_id: ID) -> None:
+        """
+        Remove all stored keydata for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The peer identifier whose keys are to be removed.
+
+        """
+
+    # -------METRICS---------
+    @abstractmethod
+    def record_latency(self, peer_id: ID, RTT: float) -> None:
+        """
+        Records a new round-trip time (RTT) latency value for the specified peer
+        using Exponentially Weighted Moving Average (EWMA).
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer for which latency is being recorded.
+
+        RTT : float
+            The round-trip time latency value to record.
+
+        """
+
+    @abstractmethod
+    def latency_EWMA(self, peer_id: ID) -> float:
+        """
+        Returns the current latency value for the specified peer using
+        Exponentially Weighted Moving Average (EWMA).
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose latency EWMA is to be returned.
+
+        """
+
+    @abstractmethod
+    def clear_metrics(self, peer_id: ID) -> None:
+        """
+        Clears the stored latency metrics for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose latency metrics are to be cleared.
+
+        """
+
+    # --------PROTO-BOOK----------
+    @abstractmethod
+    def get_protocols(self, peer_id: ID) -> list[str]:
+        """
+        Retrieve the protocols associated with the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+
+        Returns
+        -------
+        list[str]
+            A list of protocol identifiers.
+
+        Raises
+        ------
+        PeerStoreError
+            If the peer ID is not found.
+
+        """
+
+    @abstractmethod
+    def add_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Add additional protocols for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+        protocols : Sequence[str]
+            The protocols to add.
+
+        """
+
+    @abstractmethod
+    def set_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Set the protocols for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+        protocols : Sequence[str]
+            The protocols to set.
+
+        """
+
+    @abstractmethod
+    def remove_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        Removes the specified protocols from the peer's protocol list.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer from which protocols will be removed.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to remove.
+
+        """
+
+    @abstractmethod
+    def supports_protocols(self, peer_id: ID, protocols: Sequence[str]) -> list[str]:
+        """
+        Returns the list of protocols from the input sequence that the peer supports.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer to check for protocol support.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to check against the peer's
+            supported protocols.
+
+        """
+
+    @abstractmethod
+    def first_supported_protocol(self, peer_id: ID, protocols: Sequence[str]) -> str:
+        """
+        Returns the first protocol from the input list that the peer supports.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer to check for supported protocols.
+
+        protocols : Sequence[str]
+            A sequence of protocol strings to check.
+
+        Returns
+        -------
+        str
+            The first matching protocol string, or an empty string
+            if none are supported.
+
+        """
+
+    @abstractmethod
+    def clear_protocol_data(self, peer_id: ID) -> None:
+        """
+        Clears all protocol data associated with the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer whose protocol data will be cleared.
+
+        """
+
+    # --------PEER-STORE--------
+    @abstractmethod
+    def peer_info(self, peer_id: ID) -> PeerInfo:
+        """
+        Retrieve the peer information for the specified peer.
+
+        Parameters
+        ----------
+        peer_id : ID
+            The identifier of the peer.
+
+        Returns
+        -------
+        PeerInfo
+            The peer information object for the given peer.
+
+        """
+
+    @abstractmethod
+    def peer_ids(self) -> list[ID]:
+        """
+        Retrieve all peer identifiers stored in the peer store.
+
+        Returns
+        -------
+        list[ID]
+            A list of all peer IDs in the store.
+
+        """
+
+    @abstractmethod
+    def clear_peerdata(self, peer_id: ID) -> None:
+        """clear_peerdata"""
+
 
 # -------------------------- listener interface.py --------------------------
 
@@ -1128,9 +1550,8 @@ class IHost(ABC):
 
         """
 
-    # FIXME: Replace with correct return type
     @abstractmethod
-    def get_mux(self) -> Any:
+    def get_mux(self) -> "Multiselect":
         """
         Retrieve the muxer instance for the host.
 
@@ -1315,6 +1736,60 @@ class IPeerData(ABC):
 
         """
 
+    @abstractmethod
+    def remove_protocols(self, protocols: Sequence[str]) -> None:
+        """
+        Removes the specified protocols from this peer's list of supported protocols.
+
+        Parameters
+        ----------
+        protocols : Sequence[str]
+            A sequence of protocol strings to be removed.
+
+        """
+
+    @abstractmethod
+    def supports_protocols(self, protocols: Sequence[str]) -> list[str]:
+        """
+        Returns the list of protocols from the input sequence that are supported
+        by this peer.
+
+        Parameters
+        ----------
+        protocols : Sequence[str]
+            A sequence of protocol strings to check against this peer's supported
+            protocols.
+
+        Returns
+        -------
+        list[str]
+            A list of protocol strings that are supported.
+
+        """
+
+    @abstractmethod
+    def first_supported_protocol(self, protocols: Sequence[str]) -> str:
+        """
+        Returns the first protocol from the input list that this peer supports.
+
+        Parameters
+        ----------
+        protocols : Sequence[str]
+            A sequence of protocol strings to check for support.
+
+        Returns
+        -------
+        str
+            The first matching protocol, or an empty string if none are supported.
+
+        """
+
+    @abstractmethod
+    def clear_protocol_data(self) -> None:
+        """
+        Clears all protocol data associated with this peer.
+        """
+
     @abstractmethod
     def add_addrs(self, addrs: Sequence[Multiaddr]) -> None:
         """
@@ -1324,6 +1799,8 @@ class IPeerData(ABC):
         ----------
         addrs : Sequence[Multiaddr]
             A sequence of multiaddresses to add.
+        ttl: inr
+            Time to live for the peer record
 
         """
 
@@ -1382,6 +1859,12 @@ class IPeerData(ABC):
 
         """
 
+    @abstractmethod
+    def clear_metadata(self) -> None:
+        """
+        Clears all metadata entries associated with this peer.
+        """
+
     @abstractmethod
     def add_pubkey(self, pubkey: PublicKey) -> None:
         """
@@ -1440,6 +1923,45 @@ class IPeerData(ABC):
 
         """
 
+    @abstractmethod
+    def clear_keydata(self) -> None:
+        """
+        Clears all cryptographic key data associated with this peer,
+        including both public and private keys.
+        """
+
+    @abstractmethod
+    def record_latency(self, new_latency: float) -> None:
+        """
+        Records a new latency measurement using
+        Exponentially Weighted Moving Average (EWMA).
+
+        Parameters
+        ----------
+        new_latency : float
+            The new round-trip time (RTT) latency value to incorporate
+            into the EWMA calculation.
+
+        """
+
+    @abstractmethod
+    def latency_EWMA(self) -> float:
+        """
+        Returns the current EWMA value of the recorded latency.
+
+        Returns
+        -------
+        float
+            The current latency estimate based on EWMA.
+
+        """
+
+    @abstractmethod
+    def clear_metrics(self) -> None:
+        """
+        Clears all latency-related metrics and resets the internal state.
+        """
+
     @abstractmethod
     def update_last_identified(self) -> None:
         """
@@ -1640,6 +2162,7 @@ class IMultiselectMuxer(ABC):
 
         """
 
+    @abstractmethod
     def get_protocols(self) -> tuple[TProtocol | None, ...]:
         """
         Retrieve the protocols for which handlers have been registered.
@@ -1650,7 +2173,6 @@ class IMultiselectMuxer(ABC):
             A tuple of registered protocol names.
 
         """
-        return tuple(self.handlers.keys())
 
     @abstractmethod
     async def negotiate(

libp2p/discovery/events/peerDiscovery.py

@@ -0,0 +1,26 @@
+from collections.abc import (
+    Callable,
+)
+
+from libp2p.abc import (
+    PeerInfo,
+)
+
+TTL: int = 60 * 60  # Time-to-live for discovered peers in seconds
+
+
+class PeerDiscovery:
+    def __init__(self) -> None:
+        self._peer_discovered_handlers: list[Callable[[PeerInfo], None]] = []
+
+    def register_peer_discovered_handler(
+        self, handler: Callable[[PeerInfo], None]
+    ) -> None:
+        self._peer_discovered_handlers.append(handler)
+
+    def emit_peer_discovered(self, peer_info: PeerInfo) -> None:
+        for handler in self._peer_discovered_handlers:
+            handler(peer_info)
+
+
+peerDiscovery = PeerDiscovery()

libp2p/discovery/mdns/broadcaster.py

@@ -0,0 +1,91 @@
+import logging
+import socket
+
+from zeroconf import (
+    EventLoopBlocked,
+    ServiceInfo,
+    Zeroconf,
+)
+
+logger = logging.getLogger("libp2p.discovery.mdns.broadcaster")
+
+
+class PeerBroadcaster:
+    """
+    Broadcasts this peer's presence on the local network using mDNS/zeroconf.
+    Registers a service with the peer's ID in the TXT record as per libp2p spec.
+    """
+
+    def __init__(
+        self,
+        zeroconf: Zeroconf,
+        service_type: str,
+        service_name: str,
+        peer_id: str,
+        port: int,
+    ):
+        self.zeroconf = zeroconf
+        self.service_type = service_type
+        self.peer_id = peer_id
+        self.port = port
+        self.service_name = service_name
+
+        # Get the local IP address
+        local_ip = self._get_local_ip()
+        hostname = socket.gethostname()
+
+        self.service_info = ServiceInfo(
+            type_=self.service_type,
+            name=self.service_name,
+            port=self.port,
+            properties={b"id": self.peer_id.encode()},
+            server=f"{hostname}.local.",
+            addresses=[socket.inet_aton(local_ip)],
+        )
+
+    def _get_local_ip(self) -> str:
+        """Get the local IP address of this machine"""
+        try:
+            # Connect to a remote address to determine the local IP
+            # This doesn't actually send data
+            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+                s.connect(("8.8.8.8", 80))
+                local_ip = s.getsockname()[0]
+            return local_ip
+        except Exception:
+            # Fallback to localhost if we can't determine the IP
+            return "127.0.0.1"
+
+    def register(self) -> None:
+        """Register the peer's mDNS service on the network."""
+        try:
+            self.zeroconf.register_service(self.service_info)
+            logger.debug(f"mDNS service registered: {self.service_name}")
+        except EventLoopBlocked as e:
+            logger.warning(
+                "EventLoopBlocked while registering mDNS '%s': %s", self.service_name, e
+            )
+        except Exception as e:
+            logger.error(
+                "Unexpected error during mDNS registration for '%s': %r",
+                self.service_name,
+                e,
+            )
+
+    def unregister(self) -> None:
+        """Unregister the peer's mDNS service from the network."""
+        try:
+            self.zeroconf.unregister_service(self.service_info)
+            logger.debug(f"mDNS service unregistered: {self.service_name}")
+        except EventLoopBlocked as e:
+            logger.warning(
+                "EventLoopBlocked while unregistering mDNS '%s': %s",
+                self.service_name,
+                e,
+            )
+        except Exception as e:
+            logger.error(
+                "Unexpected error during mDNS unregistration for '%s': %r",
+                self.service_name,
+                e,
+            )

libp2p/discovery/mdns/listener.py

@@ -0,0 +1,83 @@
+import logging
+import socket
+
+from zeroconf import (
+    ServiceBrowser,
+    ServiceInfo,
+    ServiceListener,
+    Zeroconf,
+)
+
+from libp2p.abc import IPeerStore, Multiaddr
+from libp2p.discovery.events.peerDiscovery import peerDiscovery
+from libp2p.peer.id import ID
+from libp2p.peer.peerinfo import PeerInfo
+
+logger = logging.getLogger("libp2p.discovery.mdns.listener")
+
+
+class PeerListener(ServiceListener):
+    """mDNS listener — now a true ServiceListener subclass."""
+
+    def __init__(
+        self,
+        peerstore: IPeerStore,
+        zeroconf: Zeroconf,
+        service_type: str,
+        service_name: str,
+    ) -> None:
+        self.peerstore = peerstore
+        self.zeroconf = zeroconf
+        self.service_type = service_type
+        self.service_name = service_name
+        self.discovered_services: dict[str, ID] = {}
+        self.browser = ServiceBrowser(self.zeroconf, self.service_type, listener=self)
+
+    def add_service(self, zc: Zeroconf, type_: str, name: str) -> None:
+        if name == self.service_name:
+            return
+        logger.debug(f"Adding service: {name}")
+        info = zc.get_service_info(type_, name, timeout=5000)
+        if not info:
+            return
+        peer_info = self._extract_peer_info(info)
+        if peer_info:
+            self.discovered_services[name] = peer_info.peer_id
+            self.peerstore.add_addrs(peer_info.peer_id, peer_info.addrs, 10)
+            peerDiscovery.emit_peer_discovered(peer_info)
+            logger.debug(f"Discovered Peer: {peer_info.peer_id}")
+
+    def remove_service(self, zc: Zeroconf, type_: str, name: str) -> None:
+        if name == self.service_name:
+            return
+        logger.debug(f"Removing service: {name}")
+        peer_id = self.discovered_services.pop(name)
+        self.peerstore.clear_addrs(peer_id)
+        logger.debug(f"Removed Peer: {peer_id}")
+
+    def update_service(self, zc: Zeroconf, type_: str, name: str) -> None:
+        info = zc.get_service_info(type_, name, timeout=5000)
+        if not info:
+            return
+        peer_info = self._extract_peer_info(info)
+        if peer_info:
+            self.peerstore.clear_addrs(peer_info.peer_id)
+            self.peerstore.add_addrs(peer_info.peer_id, peer_info.addrs, 10)
+            logger.debug(f"Updated Peer {peer_info.peer_id}")
+
+    def _extract_peer_info(self, info: ServiceInfo) -> PeerInfo | None:
+        try:
+            addrs = [
+                Multiaddr(f"/ip4/{socket.inet_ntoa(addr)}/tcp/{info.port}")
+                for addr in info.addresses
+            ]
+            pid_bytes = info.properties.get(b"id")
+            if not pid_bytes:
+                return None
+            pid = ID.from_base58(pid_bytes.decode())
+            return PeerInfo(peer_id=pid, addrs=addrs)
+        except Exception:
+            return None
+
+    def stop(self) -> None:
+        self.browser.cancel()

libp2p/discovery/mdns/mdns.py

@@ -0,0 +1,73 @@
+"""
+mDNS-based peer discovery for py-libp2p.
+Conforms to https://github.com/libp2p/specs/blob/master/discovery/mdns.md
+Uses zeroconf for mDNS broadcast/listen. Async operations use trio.
+"""
+
+import logging
+
+from zeroconf import (
+    Zeroconf,
+)
+
+from libp2p.abc import (
+    INetworkService,
+)
+
+from .broadcaster import (
+    PeerBroadcaster,
+)
+from .listener import (
+    PeerListener,
+)
+from .utils import (
+    stringGen,
+)
+
+logger = logging.getLogger("libp2p.discovery.mdns")
+
+SERVICE_TYPE = "_p2p._udp.local."
+MCAST_PORT = 5353
+MCAST_ADDR = "224.0.0.251"
+
+
+class MDNSDiscovery:
+    """
+    mDNS-based peer discovery for py-libp2p, using zeroconf.
+    Conforms to the libp2p mDNS discovery spec.
+    """
+
+    def __init__(self, swarm: INetworkService, port: int = 8000):
+        self.peer_id = str(swarm.get_peer_id())
+        self.port = port
+        self.zeroconf = Zeroconf()
+        self.serviceName = f"{stringGen()}.{SERVICE_TYPE}"
+        self.peerstore = swarm.peerstore
+        self.swarm = swarm
+        self.broadcaster = PeerBroadcaster(
+            zeroconf=self.zeroconf,
+            service_type=SERVICE_TYPE,
+            service_name=self.serviceName,
+            peer_id=self.peer_id,
+            port=self.port,
+        )
+        self.listener = PeerListener(
+            zeroconf=self.zeroconf,
+            peerstore=self.peerstore,
+            service_type=SERVICE_TYPE,
+            service_name=self.serviceName,
+        )
+
+    def start(self) -> None:
+        """Register this peer and start listening for others."""
+        logger.debug(
+            f"Starting mDNS discovery for peer {self.peer_id} on port {self.port}"
+        )
+        self.broadcaster.register()
+        # Listener is started in constructor
+
+    def stop(self) -> None:
+        """Unregister this peer and clean up zeroconf resources."""
+        logger.debug("Stopping mDNS discovery")
+        self.broadcaster.unregister()
+        self.zeroconf.close()

libp2p/discovery/mdns/utils.py

@@ -0,0 +1,11 @@
+import random
+import string
+
+
+def stringGen(len: int = 63) -> str:
+    """Generate a random string of lowercase letters and digits."""
+    charset = string.ascii_lowercase + string.digits
+    result = []
+    for _ in range(len):
+        result.append(random.choice(charset))
+    return "".join(result)

libp2p/host/basic_host.py

@@ -29,6 +29,7 @@ from libp2p.custom_types import (
     StreamHandlerFn,
     TProtocol,
 )
+from libp2p.discovery.mdns.mdns import MDNSDiscovery
 from libp2p.host.defaults import (
     get_default_protocols,
 )
@@ -70,6 +71,7 @@ if TYPE_CHECKING:
 
 
 logger = logging.getLogger("libp2p.network.basic_host")
+DEFAULT_NEGOTIATE_TIMEOUT = 5
 
 
 class BasicHost(IHost):
@@ -89,15 +91,20 @@ class BasicHost(IHost):
     def __init__(
         self,
         network: INetworkService,
+        enable_mDNS: bool = False,
         default_protocols: Optional["OrderedDict[TProtocol, StreamHandlerFn]"] = None,
+        negotitate_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
     ) -> None:
         self._network = network
         self._network.set_stream_handler(self._swarm_stream_handler)
         self.peerstore = self._network.peerstore
+        self.negotiate_timeout = negotitate_timeout
         # Protocol muxing
         default_protocols = default_protocols or get_default_protocols(self)
         self.multiselect = Multiselect(dict(default_protocols.items()))
         self.multiselect_client = MultiselectClient()
+        if enable_mDNS:
+            self.mDNS = MDNSDiscovery(network)
 
     def get_id(self) -> ID:
         """
@@ -162,7 +169,14 @@ class BasicHost(IHost):
             network = self.get_network()
             async with background_trio_service(network):
                 await network.listen(*listen_addrs)
-                yield
+                if hasattr(self, "mDNS") and self.mDNS is not None:
+                    logger.debug("Starting mDNS Discovery")
+                    self.mDNS.start()
+                try:
+                    yield
+                finally:
+                    if hasattr(self, "mDNS") and self.mDNS is not None:
+                        self.mDNS.stop()
 
         return _run()
 
@@ -178,7 +192,10 @@ class BasicHost(IHost):
         self.multiselect.add_handler(protocol_id, stream_handler)
 
     async def new_stream(
-        self, peer_id: ID, protocol_ids: Sequence[TProtocol]
+        self,
+        peer_id: ID,
+        protocol_ids: Sequence[TProtocol],
+        negotitate_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
     ) -> INetStream:
         """
         :param peer_id: peer_id that host is connecting
@@ -190,7 +207,9 @@ class BasicHost(IHost):
         # Perform protocol muxing to determine protocol to use
         try:
             selected_protocol = await self.multiselect_client.select_one_of(
-                list(protocol_ids), MultiselectCommunicator(net_stream)
+                list(protocol_ids),
+                MultiselectCommunicator(net_stream),
+                negotitate_timeout,
             )
         except MultiselectClientError as error:
             logger.debug("fail to open a stream to peer %s, error=%s", peer_id, error)
@@ -200,7 +219,12 @@ class BasicHost(IHost):
         net_stream.set_protocol(selected_protocol)
         return net_stream
 
-    async def send_command(self, peer_id: ID, command: str) -> list[str]:
+    async def send_command(
+        self,
+        peer_id: ID,
+        command: str,
+        response_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
+    ) -> list[str]:
         """
         Send a multistream-select command to the specified peer and return
         the response.
@@ -214,7 +238,7 @@ class BasicHost(IHost):
 
         try:
             response = await self.multiselect_client.query_multistream_command(
-                MultiselectCommunicator(new_stream), command
+                MultiselectCommunicator(new_stream), command, response_timeout
             )
         except MultiselectClientError as error:
             logger.debug("fail to open a stream to peer %s, error=%s", peer_id, error)
@@ -253,7 +277,7 @@ class BasicHost(IHost):
         # Perform protocol muxing to determine protocol to use
         try:
             protocol, handler = await self.multiselect.negotiate(
-                MultiselectCommunicator(net_stream)
+                MultiselectCommunicator(net_stream), self.negotiate_timeout
             )
         except MultiselectError as error:
             peer_id = net_stream.muxed_conn.peer_id

libp2p/host/routed_host.py

@@ -18,8 +18,10 @@ from libp2p.peer.peerinfo import (
 class RoutedHost(BasicHost):
     _router: IPeerRouting
 
-    def __init__(self, network: INetworkService, router: IPeerRouting):
-        super().__init__(network)
+    def __init__(
+        self, network: INetworkService, router: IPeerRouting, enable_mDNS: bool = False
+    ):
+        super().__init__(network, enable_mDNS)
         self._router = router
 
     async def connect(self, peer_info: PeerInfo) -> None:

libp2p/identity/identify/identify.py

@@ -59,7 +59,7 @@ def _mk_identify_protobuf(
 ) -> Identify:
     public_key = host.get_public_key()
     laddrs = host.get_addrs()
-    protocols = host.get_mux().get_protocols()
+    protocols = tuple(str(p) for p in host.get_mux().get_protocols() if p is not None)
 
     observed_addr = observed_multiaddr.to_bytes() if observed_multiaddr else b""
     return Identify(

libp2p/identity/identify_push/identify_push.py

@@ -40,6 +40,7 @@ logger = logging.getLogger(__name__)
 ID_PUSH = TProtocol("/ipfs/id/push/1.0.0")
 PROTOCOL_VERSION = "ipfs/0.1.0"
 AGENT_VERSION = get_agent_version()
+CONCURRENCY_LIMIT = 10
 
 
 def identify_push_handler_for(host: IHost) -> StreamHandlerFn:
@@ -132,7 +133,10 @@ async def _update_peerstore_from_identify(
 
 
 async def push_identify_to_peer(
-    host: IHost, peer_id: ID, observed_multiaddr: Multiaddr | None = None
+    host: IHost,
+    peer_id: ID,
+    observed_multiaddr: Multiaddr | None = None,
+    limit: trio.Semaphore = trio.Semaphore(CONCURRENCY_LIMIT),
 ) -> bool:
     """
     Push an identify message to a specific peer.
@@ -146,25 +150,26 @@ async def push_identify_to_peer(
         True if the push was successful, False otherwise.
 
     """
-    try:
-        # Create a new stream to the peer using the identify/push protocol
-        stream = await host.new_stream(peer_id, [ID_PUSH])
+    async with limit:
+        try:
+            # Create a new stream to the peer using the identify/push protocol
+            stream = await host.new_stream(peer_id, [ID_PUSH])
 
-        # Create the identify message
-        identify_msg = _mk_identify_protobuf(host, observed_multiaddr)
-        response = identify_msg.SerializeToString()
+            # Create the identify message
+            identify_msg = _mk_identify_protobuf(host, observed_multiaddr)
+            response = identify_msg.SerializeToString()
 
-        # Send the identify message
-        await stream.write(response)
+            # Send the identify message
+            await stream.write(response)
 
-        # Close the stream
-        await stream.close()
+            # Close the stream
+            await stream.close()
 
-        logger.debug("Successfully pushed identify to peer %s", peer_id)
-        return True
-    except Exception as e:
-        logger.error("Error pushing identify to peer %s: %s", peer_id, e)
-        return False
+            logger.debug("Successfully pushed identify to peer %s", peer_id)
+            return True
+        except Exception as e:
+            logger.error("Error pushing identify to peer %s: %s", peer_id, e)
+            return False
 
 
 async def push_identify_to_peers(
@@ -179,13 +184,10 @@ async def push_identify_to_peers(
     """
     if peer_ids is None:
         # Get all connected peers
-        peer_ids = set(host.get_peerstore().peer_ids())
+        peer_ids = set(host.get_connected_peers())
 
     # Push to each peer in parallel using a trio.Nursery
-    # TODO: Consider using a bounded nursery to limit concurrency
-    # and avoid overwhelming the network. This can be done by using
-    # trio.open_nursery(max_concurrent=10) or similar.
-    # For now, we will use an unbounded nursery for simplicity.
+    # limiting concurrent connections to 10
     async with trio.open_nursery() as nursery:
         for peer_id in peer_ids:
             nursery.start_soon(push_identify_to_peer, host, peer_id, observed_multiaddr)

libp2p/peer/peerdata.py

@@ -18,6 +18,13 @@ from libp2p.crypto.keys import (
     PublicKey,
 )
 
+"""
+Latency EWMA Smoothing governs the deacy of the EWMA (the speed at which
+is changes). This must be a normalized (0-1) value.
+1 is 100% change, 0 is no change.
+"""
+LATENCY_EWMA_SMOOTHING = 0.1
+
 
 class PeerData(IPeerData):
     pubkey: PublicKey | None
@@ -27,6 +34,7 @@ class PeerData(IPeerData):
     addrs: list[Multiaddr]
     last_identified: int
     ttl: int  # Keep ttl=0 by default for always valid
+    latmap: float
 
     def __init__(self) -> None:
         self.pubkey = None
@@ -36,6 +44,9 @@ class PeerData(IPeerData):
         self.addrs = []
         self.last_identified = int(time.time())
         self.ttl = 0
+        self.latmap = 0
+
+    # --------PROTO-BOOK--------
 
     def get_protocols(self) -> list[str]:
         """
@@ -55,6 +66,37 @@ class PeerData(IPeerData):
         """
         self.protocols = list(protocols)
 
+    def remove_protocols(self, protocols: Sequence[str]) -> None:
+        """
+        :param protocols: protocols to remove
+        """
+        for protocol in protocols:
+            if protocol in self.protocols:
+                self.protocols.remove(protocol)
+
+    def supports_protocols(self, protocols: Sequence[str]) -> list[str]:
+        """
+        :param protocols: protocols to check from
+        :return: all supported protocols in the given list
+        """
+        return [proto for proto in protocols if proto in self.protocols]
+
+    def first_supported_protocol(self, protocols: Sequence[str]) -> str:
+        """
+        :param protocols: protocols to check from
+        :return: first supported protocol in the given list
+        """
+        for protocol in protocols:
+            if protocol in self.protocols:
+                return protocol
+
+        return "None supported"
+
+    def clear_protocol_data(self) -> None:
+        """Clear all protocols"""
+        self.protocols = []
+
+    # -------ADDR-BOOK---------
     def add_addrs(self, addrs: Sequence[Multiaddr]) -> None:
         """
         :param addrs: multiaddresses to add
@@ -73,6 +115,7 @@ class PeerData(IPeerData):
         """Clear all addresses."""
         self.addrs = []
 
+    # -------METADATA-----------
     def put_metadata(self, key: str, val: Any) -> None:
         """
         :param key: key in KV pair
@@ -90,6 +133,11 @@ class PeerData(IPeerData):
             return self.metadata[key]
         raise PeerDataError("key not found")
 
+    def clear_metadata(self) -> None:
+        """Clears metadata."""
+        self.metadata = {}
+
+    # -------KEY-BOOK---------------
     def add_pubkey(self, pubkey: PublicKey) -> None:
         """
         :param pubkey:
@@ -120,9 +168,41 @@ class PeerData(IPeerData):
             raise PeerDataError("private key not found")
         return self.privkey
 
+    def clear_keydata(self) -> None:
+        """Clears keydata"""
+        self.pubkey = None
+        self.privkey = None
+
+    # ----------METRICS--------------
+    def record_latency(self, new_latency: float) -> None:
+        """
+        Records a new latency measurement for the given peer
+        using Exponentially Weighted Moving Average (EWMA)
+        :param new_latency: the new latency value
+        """
+        s = LATENCY_EWMA_SMOOTHING
+        if s > 1 or s < 0:
+            s = 0.1
+
+        if self.latmap == 0:
+            self.latmap = new_latency
+        else:
+            prev = self.latmap
+            updated = ((1.0 - s) * prev) + (s * new_latency)
+            self.latmap = updated
+
+    def latency_EWMA(self) -> float:
+        """Returns the latency EWMA value"""
+        return self.latmap
+
+    def clear_metrics(self) -> None:
+        """Clear the latency metrics"""
+        self.latmap = 0
+
     def update_last_identified(self) -> None:
         self.last_identified = int(time.time())
 
+    # ----------TTL------------------
     def get_last_identified(self) -> int:
         """
         :return: last identified timestamp

libp2p/peer/peerstore.py

@@ -2,6 +2,7 @@ from collections import (
     defaultdict,
 )
 from collections.abc import (
+    AsyncIterable,
     Sequence,
 )
 from typing import (
@@ -11,6 +12,8 @@ from typing import (
 from multiaddr import (
     Multiaddr,
 )
+import trio
+from trio import MemoryReceiveChannel, MemorySendChannel
 
 from libp2p.abc import (
     IPeerStore,
@@ -40,6 +43,7 @@ class PeerStore(IPeerStore):
 
     def __init__(self) -> None:
         self.peer_data_map = defaultdict(PeerData)
+        self.addr_update_channels: dict[ID, MemorySendChannel[Multiaddr]] = {}
 
     def peer_info(self, peer_id: ID) -> PeerInfo:
         """
@@ -53,6 +57,33 @@ class PeerStore(IPeerStore):
             return PeerInfo(peer_id, peer_data.get_addrs())
         raise PeerStoreError("peer ID not found")
 
+    def peer_ids(self) -> list[ID]:
+        """
+        :return: all of the peer IDs stored in peer store
+        """
+        return list(self.peer_data_map.keys())
+
+    def clear_peerdata(self, peer_id: ID) -> None:
+        """Clears all data associated with the given peer_id."""
+        if peer_id in self.peer_data_map:
+            del self.peer_data_map[peer_id]
+        else:
+            raise PeerStoreError("peer ID not found")
+
+    def valid_peer_ids(self) -> list[ID]:
+        """
+        :return: all of the valid peer IDs stored in peer store
+        """
+        valid_peer_ids: list[ID] = []
+        for peer_id, peer_data in self.peer_data_map.items():
+            if not peer_data.is_expired():
+                valid_peer_ids.append(peer_id)
+            else:
+                peer_data.clear_addrs()
+        return valid_peer_ids
+
+    # --------PROTO-BOOK--------
+
     def get_protocols(self, peer_id: ID) -> list[str]:
         """
         :param peer_id: peer ID to get protocols for
@@ -79,23 +110,31 @@ class PeerStore(IPeerStore):
         peer_data = self.peer_data_map[peer_id]
         peer_data.set_protocols(list(protocols))
 
-    def peer_ids(self) -> list[ID]:
+    def remove_protocols(self, peer_id: ID, protocols: Sequence[str]) -> None:
+        """
+        :param peer_id: peer ID to get info for
+        :param protocols: unsupported protocols to remove
+        """
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.remove_protocols(protocols)
+
+    def supports_protocols(self, peer_id: ID, protocols: Sequence[str]) -> list[str]:
         """
         :return: all of the peer IDs stored in peer store
         """
-        return list(self.peer_data_map.keys())
+        peer_data = self.peer_data_map[peer_id]
+        return peer_data.supports_protocols(protocols)
 
-    def valid_peer_ids(self) -> list[ID]:
-        """
-        :return: all of the valid peer IDs stored in peer store
-        """
-        valid_peer_ids: list[ID] = []
-        for peer_id, peer_data in self.peer_data_map.items():
-            if not peer_data.is_expired():
-                valid_peer_ids.append(peer_id)
-            else:
-                peer_data.clear_addrs()
-        return valid_peer_ids
+    def first_supported_protocol(self, peer_id: ID, protocols: Sequence[str]) -> str:
+        peer_data = self.peer_data_map[peer_id]
+        return peer_data.first_supported_protocol(protocols)
+
+    def clear_protocol_data(self, peer_id: ID) -> None:
+        """Clears prtocoldata"""
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.clear_protocol_data()
+
+    # ------METADATA---------
 
     def get(self, peer_id: ID, key: str) -> Any:
         """
@@ -121,6 +160,13 @@ class PeerStore(IPeerStore):
         peer_data = self.peer_data_map[peer_id]
         peer_data.put_metadata(key, val)
 
+    def clear_metadata(self, peer_id: ID) -> None:
+        """Clears metadata"""
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.clear_metadata()
+
+    # -------ADDR-BOOK--------
+
     def add_addr(self, peer_id: ID, addr: Multiaddr, ttl: int = 0) -> None:
         """
         :param peer_id: peer ID to add address for
@@ -140,6 +186,13 @@ class PeerStore(IPeerStore):
         peer_data.set_ttl(ttl)
         peer_data.update_last_identified()
 
+        if peer_id in self.addr_update_channels:
+            for addr in addrs:
+                try:
+                    self.addr_update_channels[peer_id].send_nowait(addr)
+                except trio.WouldBlock:
+                    pass  # Or consider logging / dropping / replacing stream
+
     def addrs(self, peer_id: ID) -> list[Multiaddr]:
         """
         :param peer_id: peer ID to get addrs for
@@ -165,7 +218,7 @@ class PeerStore(IPeerStore):
 
     def peers_with_addrs(self) -> list[ID]:
         """
-        :return: all of the peer IDs which has addrs stored in peer store
+        :return: all of the peer IDs which has addrsfloat stored in peer store
         """
         # Add all peers with addrs at least 1 to output
         output: list[ID] = []
@@ -179,6 +232,27 @@ class PeerStore(IPeerStore):
                     peer_data.clear_addrs()
         return output
 
+    async def addr_stream(self, peer_id: ID) -> AsyncIterable[Multiaddr]:
+        """
+        Returns an async stream of newly added addresses for the given peer.
+
+        This function allows consumers to subscribe to address updates for a peer
+        and receive each new address as it is added via `add_addr` or `add_addrs`.
+
+        :param peer_id: The ID of the peer to monitor address updates for.
+        :return: An async iterator yielding Multiaddr instances as they are added.
+        """
+        send: MemorySendChannel[Multiaddr]
+        receive: MemoryReceiveChannel[Multiaddr]
+
+        send, receive = trio.open_memory_channel(0)
+        self.addr_update_channels[peer_id] = send
+
+        async for addr in receive:
+            yield addr
+
+    # -------KEY-BOOK---------
+
     def add_pubkey(self, peer_id: ID, pubkey: PublicKey) -> None:
         """
         :param peer_id: peer ID to add public key for
@@ -239,6 +313,45 @@ class PeerStore(IPeerStore):
         self.add_pubkey(peer_id, key_pair.public_key)
         self.add_privkey(peer_id, key_pair.private_key)
 
+    def peer_with_keys(self) -> list[ID]:
+        """Returns the peer_ids for which keys are stored"""
+        return [
+            peer_id
+            for peer_id, pdata in self.peer_data_map.items()
+            if pdata.pubkey is not None
+        ]
+
+    def clear_keydata(self, peer_id: ID) -> None:
+        """Clears the keys of the peer"""
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.clear_keydata()
+
+    # --------METRICS--------
+
+    def record_latency(self, peer_id: ID, RTT: float) -> None:
+        """
+        Records a new latency measurement for the given peer
+        using Exponentially Weighted Moving Average (EWMA)
+
+        :param peer_id: peer ID to get private key for
+        :param RTT: the new latency value (round trip time)
+        """
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.record_latency(RTT)
+
+    def latency_EWMA(self, peer_id: ID) -> float:
+        """
+        :param peer_id: peer ID to get private key for
+        :return: The latency EWMA value for that peer
+        """
+        peer_data = self.peer_data_map[peer_id]
+        return peer_data.latency_EWMA()
+
+    def clear_metrics(self, peer_id: ID) -> None:
+        """Clear the latency metrics"""
+        peer_data = self.peer_data_map[peer_id]
+        peer_data.clear_metrics()
+
 
 class PeerStoreError(KeyError):
     """Raised when peer ID is not found in peer store."""

libp2p/protocol_muxer/multiselect.py

@@ -1,3 +1,5 @@
+import trio
+
 from libp2p.abc import (
     IMultiselectCommunicator,
     IMultiselectMuxer,
@@ -14,6 +16,7 @@ from .exceptions import (
 
 MULTISELECT_PROTOCOL_ID = "/multistream/1.0.0"
 PROTOCOL_NOT_FOUND_MSG = "na"
+DEFAULT_NEGOTIATE_TIMEOUT = 5
 
 
 class Multiselect(IMultiselectMuxer):
@@ -47,47 +50,68 @@ class Multiselect(IMultiselectMuxer):
 
     # FIXME: Make TProtocol Optional[TProtocol] to keep types consistent
     async def negotiate(
-        self, communicator: IMultiselectCommunicator
+        self,
+        communicator: IMultiselectCommunicator,
+        negotiate_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
     ) -> tuple[TProtocol, StreamHandlerFn | None]:
         """
         Negotiate performs protocol selection.
 
         :param stream: stream to negotiate on
+        :param negotiate_timeout: timeout for negotiation
         :return: selected protocol name, handler function
         :raise MultiselectError: raised when negotiation failed
         """
-        await self.handshake(communicator)
+        try:
+            with trio.fail_after(negotiate_timeout):
+                await self.handshake(communicator)
 
-        while True:
-            try:
-                command = await communicator.read()
-            except MultiselectCommunicatorError as error:
-                raise MultiselectError() from error
-
-            if command == "ls":
-                supported_protocols = [p for p in self.handlers.keys() if p is not None]
-                response = "\n".join(supported_protocols) + "\n"
-
-                try:
-                    await communicator.write(response)
-                except MultiselectCommunicatorError as error:
-                    raise MultiselectError() from error
-
-            else:
-                protocol = TProtocol(command)
-                if protocol in self.handlers:
+                while True:
                     try:
-                        await communicator.write(protocol)
+                        command = await communicator.read()
                     except MultiselectCommunicatorError as error:
                         raise MultiselectError() from error
 
-                    return protocol, self.handlers[protocol]
-                try:
-                    await communicator.write(PROTOCOL_NOT_FOUND_MSG)
-                except MultiselectCommunicatorError as error:
-                    raise MultiselectError() from error
+                    if command == "ls":
+                        supported_protocols = [
+                            p for p in self.handlers.keys() if p is not None
+                        ]
+                        response = "\n".join(supported_protocols) + "\n"
 
-        raise MultiselectError("Negotiation failed: no matching protocol")
+                        try:
+                            await communicator.write(response)
+                        except MultiselectCommunicatorError as error:
+                            raise MultiselectError() from error
+
+                    else:
+                        protocol = TProtocol(command)
+                        if protocol in self.handlers:
+                            try:
+                                await communicator.write(protocol)
+                            except MultiselectCommunicatorError as error:
+                                raise MultiselectError() from error
+
+                            return protocol, self.handlers[protocol]
+                        try:
+                            await communicator.write(PROTOCOL_NOT_FOUND_MSG)
+                        except MultiselectCommunicatorError as error:
+                            raise MultiselectError() from error
+
+                raise MultiselectError("Negotiation failed: no matching protocol")
+        except trio.TooSlowError:
+            raise MultiselectError("handshake read timeout")
+
+    def get_protocols(self) -> tuple[TProtocol | None, ...]:
+        """
+        Retrieve the protocols for which handlers have been registered.
+
+        Returns
+        -------
+        tuple[TProtocol, ...]
+            A tuple of registered protocol names.
+
+        """
+        return tuple(self.handlers.keys())
 
     async def handshake(self, communicator: IMultiselectCommunicator) -> None:
         """

libp2p/protocol_muxer/multiselect_client.py

@@ -2,6 +2,8 @@ from collections.abc import (
     Sequence,
 )
 
+import trio
+
 from libp2p.abc import (
     IMultiselectClient,
     IMultiselectCommunicator,
@@ -17,6 +19,7 @@ from .exceptions import (
 
 MULTISELECT_PROTOCOL_ID = "/multistream/1.0.0"
 PROTOCOL_NOT_FOUND_MSG = "na"
+DEFAULT_NEGOTIATE_TIMEOUT = 5
 
 
 class MultiselectClient(IMultiselectClient):
@@ -40,6 +43,7 @@ class MultiselectClient(IMultiselectClient):
 
         try:
             handshake_contents = await communicator.read()
+
         except MultiselectCommunicatorError as error:
             raise MultiselectClientError() from error
 
@@ -47,7 +51,10 @@ class MultiselectClient(IMultiselectClient):
             raise MultiselectClientError("multiselect protocol ID mismatch")
 
     async def select_one_of(
-        self, protocols: Sequence[TProtocol], communicator: IMultiselectCommunicator
+        self,
+        protocols: Sequence[TProtocol],
+        communicator: IMultiselectCommunicator,
+        negotitate_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
     ) -> TProtocol:
         """
         For each protocol, send message to multiselect selecting protocol and
@@ -56,22 +63,32 @@ class MultiselectClient(IMultiselectClient):
 
         :param protocol: protocol to select
         :param communicator: communicator to use to communicate with counterparty
+        :param negotiate_timeout: timeout for negotiation
         :return: selected protocol
         :raise MultiselectClientError: raised when protocol negotiation failed
         """
-        await self.handshake(communicator)
+        try:
+            with trio.fail_after(negotitate_timeout):
+                await self.handshake(communicator)
 
-        for protocol in protocols:
-            try:
-                selected_protocol = await self.try_select(communicator, protocol)
-                return selected_protocol
-            except MultiselectClientError:
-                pass
+                for protocol in protocols:
+                    try:
+                        selected_protocol = await self.try_select(
+                            communicator, protocol
+                        )
+                        return selected_protocol
+                    except MultiselectClientError:
+                        pass
 
-        raise MultiselectClientError("protocols not supported")
+                raise MultiselectClientError("protocols not supported")
+        except trio.TooSlowError:
+            raise MultiselectClientError("response timed out")
 
     async def query_multistream_command(
-        self, communicator: IMultiselectCommunicator, command: str
+        self,
+        communicator: IMultiselectCommunicator,
+        command: str,
+        response_timeout: int = DEFAULT_NEGOTIATE_TIMEOUT,
     ) -> list[str]:
         """
         Send a multistream-select command over the given communicator and return
@@ -79,26 +96,32 @@ class MultiselectClient(IMultiselectClient):
 
         :param communicator: communicator to use to communicate with counterparty
         :param command: supported multistream-select command(e.g., ls)
+        :param negotiate_timeout: timeout for negotiation
         :raise MultiselectClientError: If the communicator fails to process data.
         :return: list of strings representing the response from peer.
         """
-        await self.handshake(communicator)
-
-        if command == "ls":
-            try:
-                await communicator.write("ls")
-            except MultiselectCommunicatorError as error:
-                raise MultiselectClientError() from error
-        else:
-            raise ValueError("Command not supported")
-
         try:
-            response = await communicator.read()
-            response_list = response.strip().splitlines()
-        except MultiselectCommunicatorError as error:
-            raise MultiselectClientError() from error
+            with trio.fail_after(response_timeout):
+                await self.handshake(communicator)
 
-        return response_list
+                if command == "ls":
+                    try:
+                        await communicator.write("ls")
+                    except MultiselectCommunicatorError as error:
+                        raise MultiselectClientError() from error
+                else:
+                    raise ValueError("Command not supported")
+
+                try:
+                    response = await communicator.read()
+                    response_list = response.strip().splitlines()
+
+                except MultiselectCommunicatorError as error:
+                    raise MultiselectClientError() from error
+
+                return response_list
+        except trio.TooSlowError:
+            raise MultiselectClientError("command response timed out")
 
     async def try_select(
         self, communicator: IMultiselectCommunicator, protocol: TProtocol
@@ -118,6 +141,7 @@ class MultiselectClient(IMultiselectClient):
 
         try:
             response = await communicator.read()
+
         except MultiselectCommunicatorError as error:
             raise MultiselectClientError() from error
 

libp2p/pubsub/floodsub.py

@@ -12,15 +12,9 @@ from libp2p.abc import (
 from libp2p.custom_types import (
     TProtocol,
 )
-from libp2p.network.stream.exceptions import (
-    StreamClosed,
-)
 from libp2p.peer.id import (
     ID,
 )
-from libp2p.utils import (
-    encode_varint_prefixed,
-)
 
 from .exceptions import (
     PubsubRouterError,
@@ -120,13 +114,7 @@ class FloodSub(IPubsubRouter):
             if peer_id not in pubsub.peers:
                 continue
             stream = pubsub.peers[peer_id]
-            # FIXME: We should add a `WriteMsg` similar to write delimited messages.
-            #   Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/master/comm.go#L107
-            try:
-                await stream.write(encode_varint_prefixed(rpc_msg.SerializeToString()))
-            except StreamClosed:
-                logger.debug("Fail to publish message to %s: stream closed", peer_id)
-                pubsub._handle_dead_peer(peer_id)
+            await pubsub.write_msg(stream, rpc_msg)
 
     async def join(self, topic: str) -> None:
         """

libp2p/pubsub/gossipsub.py

@@ -24,9 +24,6 @@ from libp2p.abc import (
 from libp2p.custom_types import (
     TProtocol,
 )
-from libp2p.network.stream.exceptions import (
-    StreamClosed,
-)
 from libp2p.peer.id import (
     ID,
 )
@@ -44,9 +41,6 @@ from libp2p.pubsub import (
 from libp2p.tools.async_service import (
     Service,
 )
-from libp2p.utils import (
-    encode_varint_prefixed,
-)
 
 from .exceptions import (
     NoPubsubAttached,
@@ -267,13 +261,10 @@ class GossipSub(IPubsubRouter, Service):
             if peer_id not in self.pubsub.peers:
                 continue
             stream = self.pubsub.peers[peer_id]
-            # FIXME: We should add a `WriteMsg` similar to write delimited messages.
-            #   Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/master/comm.go#L107
-            try:
-                await stream.write(encode_varint_prefixed(rpc_msg.SerializeToString()))
-            except StreamClosed:
-                logger.debug("Fail to publish message to %s: stream closed", peer_id)
-                self.pubsub._handle_dead_peer(peer_id)
+
+            # TODO: Go use `sendRPC`, which possibly piggybacks gossip/control messages.
+            await self.pubsub.write_msg(stream, rpc_msg)
+
         for topic in pubsub_msg.topicIDs:
             self.time_since_last_publish[topic] = int(time.time())
 
@@ -829,8 +820,6 @@ class GossipSub(IPubsubRouter, Service):
 
         packet.publish.extend(msgs_to_forward)
 
-        # 2) Serialize that packet
-        rpc_msg: bytes = packet.SerializeToString()
         if self.pubsub is None:
             raise NoPubsubAttached
 
@@ -844,14 +833,7 @@ class GossipSub(IPubsubRouter, Service):
         peer_stream = self.pubsub.peers[sender_peer_id]
 
         # 4) And write the packet to the stream
-        try:
-            await peer_stream.write(encode_varint_prefixed(rpc_msg))
-        except StreamClosed:
-            logger.debug(
-                "Fail to responed to iwant request from %s: stream closed",
-                sender_peer_id,
-            )
-            self.pubsub._handle_dead_peer(sender_peer_id)
+        await self.pubsub.write_msg(peer_stream, packet)
 
     async def handle_graft(
         self, graft_msg: rpc_pb2.ControlGraft, sender_peer_id: ID
@@ -993,8 +975,6 @@ class GossipSub(IPubsubRouter, Service):
         packet: rpc_pb2.RPC = rpc_pb2.RPC()
         packet.control.CopyFrom(control_msg)
 
-        rpc_msg: bytes = packet.SerializeToString()
-
         # Get stream for peer from pubsub
         if to_peer not in self.pubsub.peers:
             logger.debug(
@@ -1004,8 +984,4 @@ class GossipSub(IPubsubRouter, Service):
         peer_stream = self.pubsub.peers[to_peer]
 
         # Write rpc to stream
-        try:
-            await peer_stream.write(encode_varint_prefixed(rpc_msg))
-        except StreamClosed:
-            logger.debug("Fail to emit control message to %s: stream closed", to_peer)
-            self.pubsub._handle_dead_peer(to_peer)
+        await self.pubsub.write_msg(peer_stream, packet)

libp2p/pubsub/pubsub.py

@@ -66,6 +66,7 @@ from libp2p.utils import (
     encode_varint_prefixed,
     read_varint_prefixed_bytes,
 )
+from libp2p.utils.varint import encode_uvarint
 
 from .pb import (
     rpc_pb2,
@@ -778,3 +779,43 @@ class Pubsub(Service, IPubsub):
 
     def _is_subscribed_to_msg(self, msg: rpc_pb2.Message) -> bool:
         return any(topic in self.topic_ids for topic in msg.topicIDs)
+
+    async def write_msg(self, stream: INetStream, rpc_msg: rpc_pb2.RPC) -> bool:
+        """
+        Write an RPC message to a stream with proper error handling.
+
+        Implements WriteMsg similar to go-msgio which is used in go-libp2p
+        Ref: https://github.com/libp2p/go-msgio/blob/master/protoio/uvarint_writer.go#L56
+
+
+        :param stream: stream to write the message to
+        :param rpc_msg: RPC message to write
+        :return: True if successful, False if stream was closed
+        """
+        try:
+            # Calculate message size first
+            msg_bytes = rpc_msg.SerializeToString()
+            msg_size = len(msg_bytes)
+
+            # Calculate varint size and allocate exact buffer size needed
+
+            varint_bytes = encode_uvarint(msg_size)
+            varint_size = len(varint_bytes)
+
+            # Allocate buffer with exact size (like Go's pool.Get())
+            buf = bytearray(varint_size + msg_size)
+
+            # Write varint length prefix to buffer (like Go's binary.PutUvarint())
+            buf[:varint_size] = varint_bytes
+
+            # Write serialized message after varint (like Go's rpc.MarshalTo())
+            buf[varint_size:] = msg_bytes
+
+            # Single write operation (like Go's s.Write(buf))
+            await stream.write(bytes(buf))
+            return True
+        except StreamClosed:
+            peer_id = stream.muxed_conn.peer_id
+            logger.debug("Fail to write message to %s: stream closed", peer_id)
+            self._handle_dead_peer(peer_id)
+            return False

libp2p/relay/circuit_v2/discovery.py

@@ -234,7 +234,8 @@ class RelayDiscovery(Service):
 
             if not callable(proto_getter):
                 return None
-
+            if peer_id not in peerstore.peer_ids():
+                return None
             try:
                 # Try to get protocols
                 proto_result = proto_getter(peer_id)
@@ -283,8 +284,6 @@ class RelayDiscovery(Service):
                 return None
 
             mux = self.host.get_mux()
-            if not hasattr(mux, "protocols"):
-                return None
 
             peer_protocols = set()
             # Get protocols from mux with proper type safety
@@ -293,7 +292,9 @@ class RelayDiscovery(Service):
                 # Get protocols with proper typing
                 mux_protocols = mux.get_protocols()
                 if isinstance(mux_protocols, (list, tuple)):
-                    available_protocols = list(mux_protocols)
+                    available_protocols = [
+                        p for p in mux.get_protocols() if p is not None
+                    ]
 
             for protocol in available_protocols:
                 try:
@@ -313,7 +314,7 @@ class RelayDiscovery(Service):
 
             self._protocol_cache[peer_id] = peer_protocols
             protocol_str = str(PROTOCOL_ID)
-            for protocol in peer_protocols:
+            for protocol in map(TProtocol, peer_protocols):
                 if protocol == protocol_str:
                     return True
             return False

libp2p/stream_muxer/muxer_multistream.py

@@ -31,9 +31,6 @@ from libp2p.stream_muxer.yamux.yamux import (
     Yamux,
 )
 
-# FIXME: add negotiate timeout to `MuxerMultistream`
-DEFAULT_NEGOTIATE_TIMEOUT = 60
-
 
 class MuxerMultistream:
     """

libp2p/stream_muxer/yamux/yamux.py

@@ -98,16 +98,32 @@ class YamuxStream(IMuxedStream):
         # Flow control: Check if we have enough send window
         total_len = len(data)
         sent = 0
-
+        logging.debug(f"Stream {self.stream_id}: Starts writing {total_len} bytes ")
         while sent < total_len:
+            # Wait for available window with timeout
+            timeout = False
             async with self.window_lock:
-                # Wait for available window
-                while self.send_window == 0 and not self.closed:
-                    # Release lock while waiting
+                if self.send_window == 0:
+                    logging.debug(
+                        f"Stream {self.stream_id}: Window is zero, waiting for update"
+                    )
+                    # Release lock and wait with timeout
                     self.window_lock.release()
-                    await trio.sleep(0.01)
+                    # To avoid re-acquiring the lock immediately,
+                    with trio.move_on_after(5.0) as cancel_scope:
+                        while self.send_window == 0 and not self.closed:
+                            await trio.sleep(0.01)
+                        # If we timed out, cancel the scope
+                        timeout = cancel_scope.cancelled_caught
+                    # Re-acquire lock
                     await self.window_lock.acquire()
 
+                # If we timed out waiting for window update, raise an error
+                if timeout:
+                    raise MuxedStreamError(
+                        "Timed out waiting for window update after 5 seconds."
+                    )
+
                 if self.closed:
                     raise MuxedStreamError("Stream is closed")
 
@@ -123,25 +139,45 @@ class YamuxStream(IMuxedStream):
                 await self.conn.secured_conn.write(header + chunk)
                 sent += to_send
 
-        # If window is getting low, consider updating
-        if self.send_window < DEFAULT_WINDOW_SIZE // 2:
-            await self.send_window_update()
-
-    async def send_window_update(self, increment: int | None = None) -> None:
-        """Send a window update to peer."""
-        if increment is None:
-            increment = DEFAULT_WINDOW_SIZE - self.recv_window
+    async def send_window_update(self, increment: int, skip_lock: bool = False) -> None:
+        """
+        Send a window update to peer.
 
+        param:increment: The amount to increment the window size by.
+        If None, uses the difference between DEFAULT_WINDOW_SIZE
+        and current receive window.
+        param:skip_lock (bool): If True, skips acquiring window_lock.
+        This should only be used when calling from a context
+        that already holds the lock.
+        """
         if increment <= 0:
+            # If increment is zero or negative, skip sending update
+            logging.debug(
+                f"Stream {self.stream_id}: Skipping window update"
+                f"(increment={increment})"
+            )
             return
+        logging.debug(
+            f"Stream {self.stream_id}: Sending window update with increment={increment}"
+        )
 
-        async with self.window_lock:
-            self.recv_window += increment
+        async def _do_window_update() -> None:
             header = struct.pack(
-                YAMUX_HEADER_FORMAT, 0, TYPE_WINDOW_UPDATE, 0, self.stream_id, increment
+                YAMUX_HEADER_FORMAT,
+                0,
+                TYPE_WINDOW_UPDATE,
+                0,
+                self.stream_id,
+                increment,
             )
             await self.conn.secured_conn.write(header)
 
+        if skip_lock:
+            await _do_window_update()
+        else:
+            async with self.window_lock:
+                await _do_window_update()
+
     async def read(self, n: int | None = -1) -> bytes:
         # Handle None value for n by converting it to -1
         if n is None:
@@ -154,55 +190,68 @@ class YamuxStream(IMuxedStream):
             )
             raise MuxedStreamEOF("Stream is closed for receiving")
 
-        # If reading until EOF (n == -1), block until stream is closed
         if n == -1:
-            while not self.recv_closed and not self.conn.event_shutting_down.is_set():
+            data = b""
+            while not self.conn.event_shutting_down.is_set():
                 # Check if there's data in the buffer
                 buffer = self.conn.stream_buffers.get(self.stream_id)
-                if buffer and len(buffer) > 0:
-                    # Wait for closure even if data is available
-                    logging.debug(
-                        f"Stream {self.stream_id}:Waiting for FIN before returning data"
-                    )
-                    await self.conn.stream_events[self.stream_id].wait()
-                    self.conn.stream_events[self.stream_id] = trio.Event()
-                else:
-                    # No data, wait for data or closure
-                    logging.debug(f"Stream {self.stream_id}: Waiting for data or FIN")
-                    await self.conn.stream_events[self.stream_id].wait()
-                    self.conn.stream_events[self.stream_id] = trio.Event()
 
-            # After loop, check if stream is closed or shutting down
-            async with self.conn.streams_lock:
-                if self.conn.event_shutting_down.is_set():
-                    logging.debug(f"Stream {self.stream_id}: Connection shutting down")
-                    raise MuxedStreamEOF("Connection shut down")
-                if self.closed:
-                    if self.reset_received:
-                        logging.debug(f"Stream {self.stream_id}: Stream was reset")
-                        raise MuxedStreamReset("Stream was reset")
-                    else:
-                        logging.debug(
-                            f"Stream {self.stream_id}: Stream closed cleanly (EOF)"
-                        )
-                        raise MuxedStreamEOF("Stream closed cleanly (EOF)")
-                buffer = self.conn.stream_buffers.get(self.stream_id)
+                # If buffer is not available, check if stream is closed
                 if buffer is None:
-                    logging.debug(
-                        f"Stream {self.stream_id}: Buffer gone, assuming closed"
-                    )
+                    logging.debug(f"Stream {self.stream_id}: No buffer available")
                     raise MuxedStreamEOF("Stream buffer closed")
+
+                # If we have data in buffer, process it
+                if len(buffer) > 0:
+                    chunk = bytes(buffer)
+                    buffer.clear()
+                    data += chunk
+
+                    # Send window update for the chunk we just read
+                    async with self.window_lock:
+                        self.recv_window += len(chunk)
+                        logging.debug(f"Stream {self.stream_id}: Update {len(chunk)}")
+                        await self.send_window_update(len(chunk), skip_lock=True)
+
+                # If stream is closed (FIN received) and buffer is empty, break
                 if self.recv_closed and len(buffer) == 0:
-                    logging.debug(f"Stream {self.stream_id}: EOF reached")
-                    raise MuxedStreamEOF("Stream is closed for receiving")
-                # Return all buffered data
-                data = bytes(buffer)
-                buffer.clear()
-                logging.debug(f"Stream {self.stream_id}: Returning {len(data)} bytes")
+                    logging.debug(f"Stream {self.stream_id}: Closed with empty buffer")
+                    break
+
+                # If stream was reset, raise reset error
+                if self.reset_received:
+                    logging.debug(f"Stream {self.stream_id}: Stream was reset")
+                    raise MuxedStreamReset("Stream was reset")
+
+                # Wait for more data or stream closure
+                logging.debug(f"Stream {self.stream_id}: Waiting for data or FIN")
+                await self.conn.stream_events[self.stream_id].wait()
+                self.conn.stream_events[self.stream_id] = trio.Event()
+
+            # After loop exit, first check if we have data to return
+            if data:
+                logging.debug(
+                    f"Stream {self.stream_id}: Returning {len(data)} bytes after loop"
+                )
                 return data
 
-        # For specific size read (n > 0), return available data immediately
-        return await self.conn.read_stream(self.stream_id, n)
+            # No data accumulated, now check why we exited the loop
+            if self.conn.event_shutting_down.is_set():
+                logging.debug(f"Stream {self.stream_id}: Connection shutting down")
+                raise MuxedStreamEOF("Connection shut down")
+
+            # Return empty data
+            return b""
+        else:
+            data = await self.conn.read_stream(self.stream_id, n)
+            async with self.window_lock:
+                self.recv_window += len(data)
+                logging.debug(
+                    f"Stream {self.stream_id}: Sending window update after read, "
+                    f"increment={len(data)}"
+                )
+                await self.send_window_update(len(data), skip_lock=True)
+            return data
 
     async def close(self) -> None:
         if not self.send_closed:
@@ -493,7 +542,7 @@ class Yamux(IMuxedConn):
                     f"type={typ}, flags={flags}, stream_id={stream_id},"
                     f"length={length}"
                 )
-                if typ == TYPE_DATA and flags & FLAG_SYN:
+                if (typ == TYPE_DATA or typ == TYPE_WINDOW_UPDATE) and flags & FLAG_SYN:
                     async with self.streams_lock:
                         if stream_id not in self.streams:
                             stream = YamuxStream(stream_id, self, False)

newsfragments/579.feature.rst

@@ -1 +0,0 @@
-Added support for ``Kademlia DHT`` in py-libp2p.

newsfragments/631.feature.rst

@@ -1,7 +0,0 @@
-Store public key and peer ID in peerstore during handshake
-
-Modified the InsecureTransport class to accept an optional peerstore parameter and updated the handshake process to store the received public key and peer ID in the peerstore when available.
-
-Added test cases to verify:
-1. The peerstore remains unchanged when handshake fails due to peer ID mismatch
-2. The handshake correctly adds a public key to a peer ID that already exists in the peerstore but doesn't have a public key yet

newsfragments/678.misc.rst

@@ -1 +0,0 @@
-Refactored gossipsub heartbeat logic to use a single helper method `_handle_topic_heartbeat` that handles both fanout and gossip heartbeats.

newsfragments/679.feature.rst

@@ -1 +0,0 @@
-Added sparse connect utility function to pubsub test utilities for creating test networks with configurable connectivity.

newsfragments/681.breaking.rst

@@ -1,2 +0,0 @@
-Reordered the arguments to `upgrade_security` to place `is_initiator` before `peer_id`, and made `peer_id` optional.
-This allows the method to reflect the fact that peer identity is not required for inbound connections.

newsfragments/684.misc.rst

@@ -1 +0,0 @@
-Uses the `decapsulate` method of the `Multiaddr` class to clean up the observed address.

newsfragments/685.feature.rst

@@ -1 +0,0 @@
-Optimized pubsub publishing to send multiple topics in a single message instead of separate messages per topic.

newsfragments/690.feature.rst

@@ -1 +0,0 @@
-added peer exchange and backoff logic as part of Gossipsub v1.1 upgrade

newsfragments/702.bugfix.rst

@@ -1 +0,0 @@
-Fixed an issue in `Pubsub` where async validators were not handled reliably under concurrency. Now uses a safe aggregator list for consistent behavior.

newsfragments/732.deprecation.rst

@@ -0,0 +1 @@
+update cryptographic dependencies: pycryptodome to ≥3.19.1, pynacl to ≥1.5.0, coincurve to ≥21.0.0

newsfragments/746.bugfix.rst

@@ -0,0 +1,3 @@
+Improved type safety in `get_mux()` and `get_protocols()` by returning properly typed values instead
+of `Any`. Also updated `identify.py` and `discovery.py` to handle `None` values safely and
+compare protocols correctly.

newsfragments/749.internal.rst

@@ -0,0 +1 @@
+Add comprehensive tests for relay_discovery method in circuit_relay_v2

newsfragments/750.feature.rst

@@ -0,0 +1 @@
+Add logic to clear_peerdata method in peerstore

pyproject.toml

@@ -1,11 +1,10 @@
-
 [build-system]
 requires = ["setuptools>=42", "wheel"]
 build-backend = "setuptools.build_meta"
 
 [project]
 name = "libp2p"
-version = "0.2.8"
+version = "0.2.9"
 description = "libp2p: The Python implementation of the libp2p networking stack"
 readme = "README.md"
 requires-python = ">=3.10, <4.0"
@@ -16,21 +15,22 @@ authors = [
 ]
 dependencies = [
     "base58>=1.0.3",
-    "coincurve>=10.0.0",
+    "coincurve>=21.0.0",
     "exceptiongroup>=1.2.0; python_version < '3.11'",
     "grpcio>=1.41.0",
     "lru-dict>=1.1.6",
     "multiaddr>=0.0.9",
     "mypy-protobuf>=3.0.0",
     "noiseprotocol>=0.3.0",
-    "protobuf>=3.20.1,<4.0.0",
-    "pycryptodome>=3.9.2",
+    "pycryptodome>=3.19.1",
+    "protobuf>=4.21.0,<5.0.0",
     "pymultihash>=0.8.2",
-    "pynacl>=1.3.0",
+    "pynacl>=1.5.0",
     "rpcudp>=3.0.0",
     "trio-typing>=0.0.4",
     "trio>=0.26.0",
     "fastecdsa==2.3.2; sys_platform != 'win32'",
+    "zeroconf (>=0.147.0,<0.148.0)",
 ]
 classifiers = [
     "Development Status :: 4 - Beta",
@@ -54,6 +54,7 @@ identify-demo = "examples.identify.identify:main"
 identify-push-demo = "examples.identify_push.identify_push_demo:run_main"
 identify-push-listener-dialer-demo = "examples.identify_push.identify_push_listener_dialer:main"
 pubsub-demo = "examples.pubsub.pubsub:main"
+mdns-demo = "examples.mDNS.mDNS:main"
 
 [project.optional-dependencies]
 dev = [
@@ -187,7 +188,7 @@ name = "Removals"
 showcontent = true
 
 [tool.bumpversion]
-current_version = "0.2.8"
+current_version = "0.2.9"
 parse = """
     (?P<major>\\d+)
     \\.(?P<minor>\\d+)

tests/core/identity/identify_push/test_identify_push.py

@@ -1,4 +1,7 @@
 import logging
+from unittest.mock import (
+    patch,
+)
 
 import pytest
 import multiaddr
@@ -17,6 +20,7 @@ from libp2p.identity.identify.pb.identify_pb2 import (
     Identify,
 )
 from libp2p.identity.identify_push.identify_push import (
+    CONCURRENCY_LIMIT,
     ID_PUSH,
     _update_peerstore_from_identify,
     identify_push_handler_for,
@@ -29,6 +33,11 @@ from libp2p.peer.peerinfo import (
 from tests.utils.factories import (
     host_pair_factory,
 )
+from tests.utils.utils import (
+    create_mock_connections,
+    run_host_forever,
+    wait_until_listening,
+)
 
 logger = logging.getLogger("libp2p.identity.identify-push-test")
 
@@ -175,6 +184,7 @@ async def test_identify_push_to_peers(security_protocol):
         host_c = new_host(key_pair=key_pair_c)
 
         # Set up the identify/push handlers
+        host_a.set_stream_handler(ID_PUSH, identify_push_handler_for(host_a))
         host_b.set_stream_handler(ID_PUSH, identify_push_handler_for(host_b))
         host_c.set_stream_handler(ID_PUSH, identify_push_handler_for(host_c))
 
@@ -204,6 +214,20 @@ async def test_identify_push_to_peers(security_protocol):
             # Check that the peer is in the peerstore
             assert peer_id_a in peerstore_c.peer_ids()
 
+            # Test for push_identify to only connected peers and not all peers
+            # Disconnect a from c.
+            await host_c.disconnect(host_a.get_id())
+
+            await push_identify_to_peers(host_c)
+
+            # Wait a bit for the push to complete
+            await trio.sleep(0.1)
+
+            # Check that host_a's peerstore has not been updated with host_c's info
+            assert host_c.get_id() not in host_a.get_peerstore().peer_ids()
+            # Check that host_b's peerstore has been updated with host_c's info
+            assert host_c.get_id() in host_b.get_peerstore().peer_ids()
+
 
 @pytest.mark.trio
 async def test_push_identify_to_peers_with_explicit_params(security_protocol):
@@ -412,3 +436,160 @@ async def test_partial_update_peerstore_from_identify(security_protocol):
         host_a_public_key = host_a.get_public_key().serialize()
         peerstore_public_key = peerstore.pubkey(peer_id).serialize()
         assert host_a_public_key == peerstore_public_key
+
+
+@pytest.mark.trio
+async def test_push_identify_to_peers_respects_concurrency_limit():
+    """
+    Test bounded concurrency for the identify/push protocol to prevent
+    network congestion.
+
+    This test verifies:
+    1. The number of concurrent tasks executing the identify push is always
+       less than or equal to CONCURRENCY_LIMIT.
+    2. An error is raised if concurrency exceeds the defined limit.
+
+    It mocks `push_identify_to_peer` to simulate delay using sleep,
+    allowing the test to measure and assert actual concurrency behavior.
+    """
+    state = {
+        "concurrency_counter": 0,
+        "max_observed": 0,
+    }
+    lock = trio.Lock()
+
+    async def mock_push_identify_to_peer(
+        host, peer_id, observed_multiaddr=None, limit=trio.Semaphore(CONCURRENCY_LIMIT)
+    ) -> bool:
+        """
+        Mock function to test concurrency by simulating an identify message.
+
+        This function patches push_identify_to_peer for testing purpose
+
+        Returns
+        -------
+        bool
+            True if the push was successful, False otherwise.
+
+        """
+        async with limit:
+            async with lock:
+                state["concurrency_counter"] += 1
+                if state["concurrency_counter"] > CONCURRENCY_LIMIT:
+                    raise RuntimeError(
+                        f"Concurrency limit exceeded: {state['concurrency_counter']}"
+                    )
+                state["max_observed"] = max(
+                    state["max_observed"], state["concurrency_counter"]
+                )
+
+            logger.debug("Successfully pushed identify to peer %s", peer_id)
+            await trio.sleep(0.05)
+
+            async with lock:
+                state["concurrency_counter"] -= 1
+
+            return True
+
+    # Create a mock host.
+    key_pair_host = create_new_key_pair()
+    host = new_host(key_pair=key_pair_host)
+
+    # Create a mock network and add mock connections to the host
+    host.get_network().connections = create_mock_connections()
+    with patch(
+        "libp2p.identity.identify_push.identify_push.push_identify_to_peer",
+        new=mock_push_identify_to_peer,
+    ):
+        await push_identify_to_peers(host)
+    assert state["max_observed"] <= CONCURRENCY_LIMIT, (
+        f"Max concurrency observed: {state['max_observed']}"
+    )
+
+
+@pytest.mark.trio
+async def test_all_peers_receive_identify_push_with_semaphore(security_protocol):
+    dummy_peers = []
+
+    async with host_pair_factory(security_protocol=security_protocol) as (host_a, _):
+        # Create dummy peers
+        for _ in range(50):
+            key_pair = create_new_key_pair()
+            dummy_host = new_host(key_pair=key_pair)
+            dummy_host.set_stream_handler(
+                ID_PUSH, identify_push_handler_for(dummy_host)
+            )
+            listen_addr = multiaddr.Multiaddr("/ip4/127.0.0.1/tcp/0")
+            dummy_peers.append((dummy_host, listen_addr))
+
+        async with trio.open_nursery() as nursery:
+            # Start all dummy hosts
+            for host, listen_addr in dummy_peers:
+                nursery.start_soon(run_host_forever, host, listen_addr)
+
+            # Wait for all hosts to finish setting up listeners
+            for host, _ in dummy_peers:
+                await wait_until_listening(host)
+
+            # Now connect host_a → dummy peers
+            for host, _ in dummy_peers:
+                await host_a.connect(info_from_p2p_addr(host.get_addrs()[0]))
+
+            await push_identify_to_peers(
+                host_a,
+            )
+
+            await trio.sleep(0.5)
+
+            peer_id_a = host_a.get_id()
+            for host, _ in dummy_peers:
+                dummy_peerstore = host.get_peerstore()
+                assert peer_id_a in dummy_peerstore.peer_ids()
+
+            nursery.cancel_scope.cancel()
+
+
+@pytest.mark.trio
+async def test_all_peers_receive_identify_push_with_semaphore_under_high_peer_load(
+    security_protocol,
+):
+    dummy_peers = []
+
+    async with host_pair_factory(security_protocol=security_protocol) as (host_a, _):
+        # Create dummy peers
+        # Breaking with more than 500 peers
+        # Trio have a async tasks limit of 1000
+        for _ in range(499):
+            key_pair = create_new_key_pair()
+            dummy_host = new_host(key_pair=key_pair)
+            dummy_host.set_stream_handler(
+                ID_PUSH, identify_push_handler_for(dummy_host)
+            )
+            listen_addr = multiaddr.Multiaddr("/ip4/127.0.0.1/tcp/0")
+            dummy_peers.append((dummy_host, listen_addr))
+
+        async with trio.open_nursery() as nursery:
+            # Start all dummy hosts
+            for host, listen_addr in dummy_peers:
+                nursery.start_soon(run_host_forever, host, listen_addr)
+
+            # Wait for all hosts to finish setting up listeners
+            for host, _ in dummy_peers:
+                await wait_until_listening(host)
+
+            # Now connect host_a → dummy peers
+            for host, _ in dummy_peers:
+                await host_a.connect(info_from_p2p_addr(host.get_addrs()[0]))
+
+            await push_identify_to_peers(
+                host_a,
+            )
+
+            await trio.sleep(0.5)
+
+            peer_id_a = host_a.get_id()
+            for host, _ in dummy_peers:
+                dummy_peerstore = host.get_peerstore()
+                assert peer_id_a in dummy_peerstore.peer_ids()
+
+            nursery.cancel_scope.cancel()

tests/core/peer/test_peerdata.py

@@ -6,10 +6,12 @@ from multiaddr import Multiaddr
 from libp2p.crypto.secp256k1 import (
     create_new_key_pair,
 )
+from libp2p.peer.id import ID
 from libp2p.peer.peerdata import (
     PeerData,
     PeerDataError,
 )
+from libp2p.peer.peerstore import PeerStore
 
 MOCK_ADDR = Multiaddr("/ip4/127.0.0.1/tcp/4001")
 MOCK_KEYPAIR = create_new_key_pair()
@@ -39,6 +41,59 @@ def test_set_protocols():
     assert peer_data.get_protocols() == protocols
 
 
+# Test case when removing protocols:
+def test_remove_protocols():
+    peer_data = PeerData()
+    protocols: Sequence[str] = ["protocol1", "protocol2"]
+    peer_data.set_protocols(protocols)
+
+    peer_data.remove_protocols(["protocol1"])
+    assert peer_data.get_protocols() == ["protocol2"]
+
+
+# Test case when clearing the protocol list:
+def test_clear_protocol_data():
+    peer_data = PeerData()
+    protocols: Sequence[str] = ["protocol1", "protocol2"]
+    peer_data.set_protocols(protocols)
+
+    peer_data.clear_protocol_data()
+    assert peer_data.get_protocols() == []
+
+
+# Test case when supports protocols:
+def test_supports_protocols():
+    peer_data = PeerData()
+    peer_data.set_protocols(["protocol1", "protocol2", "protocol3"])
+
+    input_protocols = ["protocol1", "protocol4", "protocol2"]
+    supported = peer_data.supports_protocols(input_protocols)
+
+    assert supported == ["protocol1", "protocol2"]
+
+
+# Test case for first supported protocol is found
+def test_first_supported_protocol_found():
+    peer_data = PeerData()
+    peer_data.set_protocols(["protocolA", "protocolB"])
+
+    input_protocols = ["protocolC", "protocolB", "protocolA"]
+    first = peer_data.first_supported_protocol(input_protocols)
+
+    assert first == "protocolB"
+
+
+# Test case for first supported protocol not found
+def test_first_supported_protocol_none():
+    peer_data = PeerData()
+    peer_data.set_protocols(["protocolX", "protocolY"])
+
+    input_protocols = ["protocolA", "protocolB"]
+    first = peer_data.first_supported_protocol(input_protocols)
+
+    assert first == "None supported"
+
+
 # Test case when adding addresses
 def test_add_addrs():
     peer_data = PeerData()
@@ -81,6 +136,15 @@ def test_get_metadata_key_not_found():
         peer_data.get_metadata("nonexistent_key")
 
 
+# Test case for clearing metadata
+def test_clear_metadata():
+    peer_data = PeerData()
+    peer_data.metadata = {"key1": "value1", "key2": "value2"}
+
+    peer_data.clear_metadata()
+    assert peer_data.metadata == {}
+
+
 # Test case for adding public key
 def test_add_pubkey():
     peer_data = PeerData()
@@ -107,3 +171,71 @@ def test_get_privkey_not_found():
     peer_data = PeerData()
     with pytest.raises(PeerDataError):
         peer_data.get_privkey()
+
+
+# Test case for returning all the peers with stored keys
+def test_peer_with_keys():
+    peer_store = PeerStore()
+    peer_id_1 = ID(b"peer1")
+    peer_id_2 = ID(b"peer2")
+
+    peer_data_1 = PeerData()
+    peer_data_2 = PeerData()
+
+    peer_data_1.pubkey = MOCK_PUBKEY
+    peer_data_2.pubkey = None
+
+    peer_store.peer_data_map = {
+        peer_id_1: peer_data_1,
+        peer_id_2: peer_data_2,
+    }
+
+    assert peer_store.peer_with_keys() == [peer_id_1]
+
+
+# Test case for clearing the key book
+def test_clear_keydata():
+    peer_store = PeerStore()
+    peer_id = ID(b"peer123")
+    peer_data = PeerData()
+
+    peer_data.pubkey = MOCK_PUBKEY
+    peer_data.privkey = MOCK_PRIVKEY
+    peer_store.peer_data_map = {peer_id: peer_data}
+
+    peer_store.clear_keydata(peer_id)
+
+    assert peer_data.pubkey is None
+    assert peer_data.privkey is None
+
+
+# Test case for recording latency for the first time
+def test_record_latency_initial():
+    peer_data = PeerData()
+    assert peer_data.latency_EWMA() == 0
+
+    peer_data.record_latency(100.0)
+    assert peer_data.latency_EWMA() == 100.0
+
+
+# Test case for updating latency
+def test_record_latency_updates_ewma():
+    peer_data = PeerData()
+    peer_data.record_latency(100.0)  # first measurement
+    first = peer_data.latency_EWMA()
+
+    peer_data.record_latency(50.0)  # second measurement
+    second = peer_data.latency_EWMA()
+
+    assert second < first  # EWMA should have smoothed downward
+    assert second > 50.0  # Not as low as the new latency
+    assert second != first
+
+
+def test_clear_metrics():
+    peer_data = PeerData()
+    peer_data.record_latency(200.0)
+    assert peer_data.latency_EWMA() == 200.0
+
+    peer_data.clear_metrics()
+    assert peer_data.latency_EWMA() == 0

tests/core/peer/test_peerstore.py

@@ -2,6 +2,7 @@ import time
 
 import pytest
 from multiaddr import Multiaddr
+import trio
 
 from libp2p.peer.id import ID
 from libp2p.peer.peerstore import (
@@ -89,3 +90,33 @@ def test_peers():
     store.add_addr(ID(b"peer3"), Multiaddr("/ip4/127.0.0.1/tcp/4001"), 10)
 
     assert set(store.peer_ids()) == {ID(b"peer1"), ID(b"peer2"), ID(b"peer3")}
+
+
+@pytest.mark.trio
+async def test_addr_stream_yields_new_addrs():
+    store = PeerStore()
+    peer_id = ID(b"peer1")
+    addr1 = Multiaddr("/ip4/127.0.0.1/tcp/4001")
+    addr2 = Multiaddr("/ip4/127.0.0.1/tcp/4002")
+
+    collected = []
+
+    async def consume_addrs():
+        async for addr in store.addr_stream(peer_id):
+            collected.append(addr)
+            if len(collected) == 2:
+                break
+
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(consume_addrs)
+        await trio.sleep(2)  # Give time for the stream to start
+
+        store.add_addr(peer_id, addr1, ttl=10)
+        await trio.sleep(0.2)
+        store.add_addr(peer_id, addr2, ttl=10)
+        await trio.sleep(0.2)
+
+        # After collecting expected addresses, cancel the stream
+        nursery.cancel_scope.cancel()
+
+    assert collected == [addr1, addr2]

tests/core/protocol_muxer/test_negotiate_timeout.py

@@ -0,0 +1,59 @@
+import pytest
+import trio
+
+from libp2p.abc import (
+    IMultiselectCommunicator,
+)
+from libp2p.custom_types import TProtocol
+from libp2p.protocol_muxer.exceptions import (
+    MultiselectClientError,
+    MultiselectError,
+)
+from libp2p.protocol_muxer.multiselect import Multiselect
+from libp2p.protocol_muxer.multiselect_client import MultiselectClient
+
+
+class DummyMultiselectCommunicator(IMultiselectCommunicator):
+    """
+    Dummy MultiSelectCommunicator to test out negotiate timmeout.
+    """
+
+    def __init__(self) -> None:
+        return
+
+    async def write(self, msg_str: str) -> None:
+        """Goes into infinite loop when .write is called"""
+        await trio.sleep_forever()
+
+    async def read(self) -> str:
+        """Returns a dummy read"""
+        return "dummy_read"
+
+
+@pytest.mark.trio
+async def test_select_one_of_timeout():
+    ECHO = TProtocol("/echo/1.0.0")
+    communicator = DummyMultiselectCommunicator()
+
+    client = MultiselectClient()
+
+    with pytest.raises(MultiselectClientError, match="response timed out"):
+        await client.select_one_of([ECHO], communicator, 2)
+
+
+@pytest.mark.trio
+async def test_query_multistream_command_timeout():
+    communicator = DummyMultiselectCommunicator()
+    client = MultiselectClient()
+
+    with pytest.raises(MultiselectClientError, match="response timed out"):
+        await client.query_multistream_command(communicator, "ls", 2)
+
+
+@pytest.mark.trio
+async def test_negotiate_timeout():
+    communicator = DummyMultiselectCommunicator()
+    server = Multiselect()
+
+    with pytest.raises(MultiselectError, match="handshake read timeout"):
+        await server.negotiate(communicator, 2)

tests/core/protocol_muxer/test_protocol_muxer.py

@@ -3,6 +3,7 @@ import pytest
 from libp2p.custom_types import (
     TProtocol,
 )
+from libp2p.protocol_muxer.multiselect import Multiselect
 from libp2p.tools.utils import (
     create_echo_stream_handler,
 )
@@ -138,3 +139,23 @@ async def test_multistream_command(security_protocol):
         # Dialer asks for unspoorted command
         with pytest.raises(ValueError, match="Command not supported"):
             await dialer.send_command(listener.get_id(), "random")
+
+
+@pytest.mark.trio
+async def test_get_protocols_returns_all_registered_protocols():
+    ms = Multiselect()
+
+    async def dummy_handler(stream):
+        pass
+
+    p1 = TProtocol("/echo/1.0.0")
+    p2 = TProtocol("/foo/1.0.0")
+    p3 = TProtocol("/bar/1.0.0")
+
+    ms.add_handler(p1, dummy_handler)
+    ms.add_handler(p2, dummy_handler)
+    ms.add_handler(p3, dummy_handler)
+
+    protocols = ms.get_protocols()
+
+    assert set(protocols) == {p1, p2, p3}

tests/core/pubsub/test_gossipsub.py

@@ -15,6 +15,7 @@ from tests.utils.factories import (
     PubsubFactory,
 )
 from tests.utils.pubsub.utils import (
+    connect_some,
     dense_connect,
     one_to_all_connect,
     sparse_connect,
@@ -590,3 +591,166 @@ async def test_sparse_connect():
                 f"received the message. Ideally all nodes should receive it, but at "
                 f"minimum {min_required} required for sparse network scalability."
             )
+
+
+@pytest.mark.trio
+async def test_connect_some_with_fewer_hosts_than_degree():
+    """Test connect_some when there are fewer hosts than degree."""
+    # Create 3 hosts with degree=5
+    async with PubsubFactory.create_batch_with_floodsub(3) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+        degree = 5
+
+        await connect_some(hosts, degree)
+        await trio.sleep(0.1)  # Allow connections to establish
+
+        # Each host should connect to all other hosts (since there are only 2 others)
+        for i, pubsub in enumerate(pubsubs_fsub):
+            connected_peers = len(pubsub.peers)
+            expected_max_connections = len(hosts) - 1  # All others
+            assert connected_peers <= expected_max_connections, (
+                f"Host {i} has {connected_peers} connections, "
+                f"but can only connect to {expected_max_connections} others"
+            )
+
+
+@pytest.mark.trio
+async def test_connect_some_degree_limit_enforced():
+    """Test that connect_some enforces degree limits and creates expected topology."""
+    # Test with small network where we can verify exact behavior
+    async with PubsubFactory.create_batch_with_floodsub(6) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+        degree = 2
+
+        await connect_some(hosts, degree)
+        await trio.sleep(0.1)
+
+        # With 6 hosts and degree=2, expected connections:
+        # Host 0 → connects to hosts 1,2 (2 peers total)
+        # Host 1 → connects to hosts 2,3 (3 peers: 0,2,3)
+        # Host 2 → connects to hosts 3,4 (4 peers: 0,1,3,4)
+        # Host 3 → connects to hosts 4,5 (3 peers: 1,2,4,5) - wait, that's 4!
+        # Host 4 → connects to host 5 (3 peers: 2,3,5)
+        # Host 5 → (2 peers: 3,4)
+
+        peer_counts = [len(pubsub.peers) for pubsub in pubsubs_fsub]
+
+        # First and last hosts should have exactly degree connections
+        assert peer_counts[0] == degree, (
+            f"Host 0 should have {degree} peers, got {peer_counts[0]}"
+        )
+        assert peer_counts[-1] <= degree, (
+            f"Last host should have ≤ {degree} peers, got {peer_counts[-1]}"
+        )
+
+        # Middle hosts may have more due to bidirectional connections
+        # but the pattern should be consistent with degree limit
+        total_connections = sum(peer_counts)
+
+        # Should be less than full mesh (each host connected to all others)
+        full_mesh_connections = len(hosts) * (len(hosts) - 1)
+        assert total_connections < full_mesh_connections, (
+            f"Got {total_connections} total connections, "
+            f"but full mesh would be {full_mesh_connections}"
+        )
+
+        # Should be more than just a chain (each host connected to next only)
+        chain_connections = 2 * (len(hosts) - 1)  # bidirectional chain
+        assert total_connections > chain_connections, (
+            f"Got {total_connections} total connections, which is too few "
+            f"(chain would be {chain_connections})"
+        )
+
+
+@pytest.mark.trio
+async def test_connect_some_degree_zero():
+    """Test edge case: degree=0 should result in no connections."""
+    # Create 5 hosts with degree=0
+    async with PubsubFactory.create_batch_with_floodsub(5) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+        degree = 0
+
+        await connect_some(hosts, degree)
+        await trio.sleep(0.1)  # Allow any potential connections to establish
+
+        # Verify no connections were made
+        for i, pubsub in enumerate(pubsubs_fsub):
+            connected_peers = len(pubsub.peers)
+            assert connected_peers == 0, (
+                f"Host {i} has {connected_peers} connections, "
+                f"but degree=0 should result in no connections"
+            )
+
+
+@pytest.mark.trio
+async def test_connect_some_negative_degree():
+    """Test edge case: negative degree should be handled gracefully."""
+    # Create 5 hosts with degree=-1
+    async with PubsubFactory.create_batch_with_floodsub(5) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+        degree = -1
+
+        await connect_some(hosts, degree)
+        await trio.sleep(0.1)  # Allow any potential connections to establish
+
+        # Verify no connections were made (negative degree should behave like 0)
+        for i, pubsub in enumerate(pubsubs_fsub):
+            connected_peers = len(pubsub.peers)
+            assert connected_peers == 0, (
+                f"Host {i} has {connected_peers} connections, "
+                f"but negative degree should result in no connections"
+            )
+
+
+@pytest.mark.trio
+async def test_sparse_connect_degree_zero():
+    """Test sparse_connect with degree=0."""
+    async with PubsubFactory.create_batch_with_floodsub(8) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+        degree = 0
+
+        await sparse_connect(hosts, degree)
+        await trio.sleep(0.1)  # Allow connections to establish
+
+        # With degree=0, sparse_connect should still create neighbor connections
+        # for connectivity (this is part of the algorithm design)
+        for i, pubsub in enumerate(pubsubs_fsub):
+            connected_peers = len(pubsub.peers)
+            # Should have some connections due to neighbor connectivity
+            # (each node connects to immediate neighbors)
+            expected_neighbors = 2  # previous and next in ring
+            assert connected_peers >= expected_neighbors, (
+                f"Host {i} has {connected_peers} connections, "
+                f"expected at least {expected_neighbors} neighbor connections"
+            )
+
+
+@pytest.mark.trio
+async def test_empty_host_list():
+    """Test edge case: empty host list should be handled gracefully."""
+    hosts = []
+
+    # All functions should handle empty lists gracefully
+    await connect_some(hosts, 5)
+    await sparse_connect(hosts, 3)
+    await dense_connect(hosts)
+
+    # If we reach here without exceptions, the test passes
+
+
+@pytest.mark.trio
+async def test_single_host():
+    """Test edge case: single host should be handled gracefully."""
+    async with PubsubFactory.create_batch_with_floodsub(1) as pubsubs_fsub:
+        hosts = [pubsub.host for pubsub in pubsubs_fsub]
+
+        # All functions should handle single host gracefully
+        await connect_some(hosts, 5)
+        await sparse_connect(hosts, 3)
+        await dense_connect(hosts)
+
+        # Single host should have no connections
+        connected_peers = len(pubsubs_fsub[0].peers)
+        assert connected_peers == 0, (
+            f"Single host has {connected_peers} connections, expected 0"
+        )

tests/core/relay/test_circuit_v2_discovery.py

@@ -105,11 +105,11 @@ async def test_relay_discovery_initialization():
 
 
 @pytest.mark.trio
-async def test_relay_discovery_find_relay():
-    """Test finding a relay node via discovery."""
+async def test_relay_discovery_find_relay_peerstore_method():
+    """Test finding a relay node via discovery using the peerstore method."""
     async with HostFactory.create_batch_and_listen(2) as hosts:
         relay_host, client_host = hosts
-        logger.info("Created hosts for test_relay_discovery_find_relay")
+        logger.info("Created host for test_relay_discovery_find_relay_peerstore_method")
         logger.info("Relay host ID: %s", relay_host.get_id())
         logger.info("Client host ID: %s", client_host.get_id())
 
@@ -144,19 +144,19 @@ async def test_relay_discovery_find_relay():
         # Start discovery service
         async with background_trio_service(client_discovery):
             await client_discovery.event_started.wait()
-            logger.info("Client discovery service started")
+            logger.info("Client discovery service started (peerstore method)")
 
-            # Wait for discovery to find the relay
-            logger.info("Waiting for relay discovery...")
+            # Wait for discovery to find the relay using the peerstore method
+            logger.info("Waiting for relay discovery using peerstore...")
 
-            # Manually trigger discovery instead of waiting
+            # Manually trigger discovery which uses peerstore as default
             await client_discovery.discover_relays()
 
             # Check if relay was found
             with trio.fail_after(DISCOVERY_TIMEOUT):
                 for _ in range(20):  # Try multiple times
                     if relay_host.get_id() in client_discovery._discovered_relays:
-                        logger.info("Relay discovered successfully")
+                        logger.info("Relay discovered successfully (peerstore method)")
                         break
 
                     # Wait and try again
@@ -164,14 +164,194 @@ async def test_relay_discovery_find_relay():
                     # Manually trigger discovery again
                     await client_discovery.discover_relays()
                 else:
-                    pytest.fail("Failed to discover relay node within timeout")
+                    pytest.fail(
+                        "Failed to discover relay node within timeout(peerstore method)"
+                    )
 
             # Verify that relay was found and is valid
             assert relay_host.get_id() in client_discovery._discovered_relays, (
-                "Relay should be discovered"
+                "Relay should be discovered (peerstore method)"
             )
             relay_info = client_discovery._discovered_relays[relay_host.get_id()]
-            assert relay_info.peer_id == relay_host.get_id(), "Peer ID should match"
+            assert relay_info.peer_id == relay_host.get_id(), (
+                "Peer ID should match (peerstore method)"
+            )
+
+
+@pytest.mark.trio
+async def test_relay_discovery_find_relay_direct_connection_method():
+    """Test finding a relay node via discovery using the direct connection method."""
+    async with HostFactory.create_batch_and_listen(2) as hosts:
+        relay_host, client_host = hosts
+        logger.info("Created hosts for test_relay_discovery_find_relay_direct_method")
+        logger.info("Relay host ID: %s", relay_host.get_id())
+        logger.info("Client host ID: %s", client_host.get_id())
+
+        # Explicitly register the protocol handlers on relay_host
+        relay_host.set_stream_handler(PROTOCOL_ID, simple_stream_handler)
+        relay_host.set_stream_handler(STOP_PROTOCOL_ID, simple_stream_handler)
+
+        # Manually add protocol to peerstore for testing, then remove to force fallback
+        client_host.get_peerstore().add_protocols(
+            relay_host.get_id(), [str(PROTOCOL_ID)]
+        )
+
+        # Set up discovery on the client host
+        client_discovery = RelayDiscovery(
+            client_host, discovery_interval=5
+        )  # Use shorter interval for testing
+
+        try:
+            # Connect peers so they can discover each other
+            with trio.fail_after(CONNECT_TIMEOUT):
+                logger.info("Connecting client host to relay host")
+                await connect(client_host, relay_host)
+                assert relay_host.get_network().connections[client_host.get_id()], (
+                    "Peers not connected"
+                )
+                logger.info("Connection established between peers")
+        except Exception as e:
+            logger.error("Failed to connect peers: %s", str(e))
+            raise
+
+        # Remove the relay from the peerstore to test fallback to direct connection
+        client_host.get_peerstore().clear_peerdata(relay_host.get_id())
+        # Make sure that peer_id is not present in peerstore
+        assert relay_host.get_id() not in client_host.get_peerstore().peer_ids()
+
+        # Start discovery service
+        async with background_trio_service(client_discovery):
+            await client_discovery.event_started.wait()
+            logger.info("Client discovery service started (direct connection method)")
+
+            # Wait for discovery to find the relay using the direct connection method
+            logger.info(
+                "Waiting for relay discovery using direct connection fallback..."
+            )
+
+            # Manually trigger discovery which should fallback to direct connection
+            await client_discovery.discover_relays()
+
+            # Check if relay was found
+            with trio.fail_after(DISCOVERY_TIMEOUT):
+                for _ in range(20):  # Try multiple times
+                    if relay_host.get_id() in client_discovery._discovered_relays:
+                        logger.info("Relay discovered successfully (direct method)")
+                        break
+
+                    # Wait and try again
+                    await trio.sleep(1)
+                    # Manually trigger discovery again
+                    await client_discovery.discover_relays()
+                else:
+                    pytest.fail(
+                        "Failed to discover relay node within timeout (direct method)"
+                    )
+
+            # Verify that relay was found and is valid
+            assert relay_host.get_id() in client_discovery._discovered_relays, (
+                "Relay should be discovered (direct method)"
+            )
+            relay_info = client_discovery._discovered_relays[relay_host.get_id()]
+            assert relay_info.peer_id == relay_host.get_id(), (
+                "Peer ID should match (direct method)"
+            )
+
+
+@pytest.mark.trio
+async def test_relay_discovery_find_relay_mux_method():
+    """
+    Test finding a relay node via discovery using the mux method
+    (fallback after direct connection fails).
+    """
+    async with HostFactory.create_batch_and_listen(2) as hosts:
+        relay_host, client_host = hosts
+        logger.info("Created hosts for test_relay_discovery_find_relay_mux_method")
+        logger.info("Relay host ID: %s", relay_host.get_id())
+        logger.info("Client host ID: %s", client_host.get_id())
+
+        # Explicitly register the protocol handlers on relay_host
+        relay_host.set_stream_handler(PROTOCOL_ID, simple_stream_handler)
+        relay_host.set_stream_handler(STOP_PROTOCOL_ID, simple_stream_handler)
+
+        client_host.set_stream_handler(PROTOCOL_ID, simple_stream_handler)
+        client_host.set_stream_handler(STOP_PROTOCOL_ID, simple_stream_handler)
+
+        # Set up discovery on the client host
+        client_discovery = RelayDiscovery(
+            client_host, discovery_interval=5
+        )  # Use shorter interval for testing
+
+        try:
+            # Connect peers so they can discover each other
+            with trio.fail_after(CONNECT_TIMEOUT):
+                logger.info("Connecting client host to relay host")
+                await connect(client_host, relay_host)
+                assert relay_host.get_network().connections[client_host.get_id()], (
+                    "Peers not connected"
+                )
+                logger.info("Connection established between peers")
+        except Exception as e:
+            logger.error("Failed to connect peers: %s", str(e))
+            raise
+
+        # Remove the relay from the peerstore to test fallback
+        client_host.get_peerstore().clear_peerdata(relay_host.get_id())
+        # Make sure that peer_id is not present in peerstore
+        assert relay_host.get_id() not in client_host.get_peerstore().peer_ids()
+
+        # Mock the _check_via_direct_connection method to return None
+        # This forces the discovery to fall back to the mux method
+        async def mock_direct_check_fails(peer_id):
+            """Mock that always returns None to force mux fallback."""
+            return None
+
+        client_discovery._check_via_direct_connection = mock_direct_check_fails
+
+        # Start discovery service
+        async with background_trio_service(client_discovery):
+            await client_discovery.event_started.wait()
+            logger.info("Client discovery service started (mux method)")
+
+            # Wait for discovery to find the relay using the mux method
+            logger.info("Waiting for relay discovery using mux fallback...")
+
+            # Manually trigger discovery which should fallback to mux method
+            await client_discovery.discover_relays()
+
+            # Check if relay was found
+            with trio.fail_after(DISCOVERY_TIMEOUT):
+                for _ in range(20):  # Try multiple times
+                    if relay_host.get_id() in client_discovery._discovered_relays:
+                        logger.info("Relay discovered successfully (mux method)")
+                        break
+
+                    # Wait and try again
+                    await trio.sleep(1)
+                    # Manually trigger discovery again
+                    await client_discovery.discover_relays()
+                else:
+                    pytest.fail(
+                        "Failed to discover relay node within timeout (mux method)"
+                    )
+
+            # Verify that relay was found and is valid
+            assert relay_host.get_id() in client_discovery._discovered_relays, (
+                "Relay should be discovered (mux method)"
+            )
+            relay_info = client_discovery._discovered_relays[relay_host.get_id()]
+            assert relay_info.peer_id == relay_host.get_id(), (
+                "Peer ID should match (mux method)"
+            )
+
+            # Verify that the protocol was cached via mux method
+            assert relay_host.get_id() in client_discovery._protocol_cache, (
+                "Protocol should be cached (mux method)"
+            )
+            assert (
+                str(PROTOCOL_ID)
+                in client_discovery._protocol_cache[relay_host.get_id()]
+            ), "Relay protocol should be in cache (mux method)"
 
 
 @pytest.mark.trio

tests/core/stream_muxer/test_yamux_interleaving.py

@@ -0,0 +1,199 @@
+import logging
+
+import pytest
+import trio
+from trio.testing import (
+    memory_stream_pair,
+)
+
+from libp2p.abc import IRawConnection
+from libp2p.crypto.ed25519 import (
+    create_new_key_pair,
+)
+from libp2p.peer.id import (
+    ID,
+)
+from libp2p.security.insecure.transport import (
+    InsecureTransport,
+)
+from libp2p.stream_muxer.yamux.yamux import (
+    Yamux,
+    YamuxStream,
+)
+
+
+class TrioStreamAdapter(IRawConnection):
+    """Adapter to make trio memory streams work with libp2p."""
+
+    def __init__(self, send_stream, receive_stream, is_initiator=False):
+        self.send_stream = send_stream
+        self.receive_stream = receive_stream
+        self.is_initiator = is_initiator
+
+    async def write(self, data: bytes) -> None:
+        logging.debug(f"Attempting to write {len(data)} bytes")
+        with trio.move_on_after(2):
+            await self.send_stream.send_all(data)
+
+    async def read(self, n: int | None = None) -> bytes:
+        if n is None or n <= 0:
+            raise ValueError("Reading unbounded or zero bytes not supported")
+        logging.debug(f"Attempting to read {n} bytes")
+        with trio.move_on_after(2):
+            data = await self.receive_stream.receive_some(n)
+            logging.debug(f"Read {len(data)} bytes")
+            return data
+
+    async def close(self) -> None:
+        logging.debug("Closing stream")
+        await self.send_stream.aclose()
+        await self.receive_stream.aclose()
+
+    def get_remote_address(self) -> tuple[str, int] | None:
+        """Return None since this is a test adapter without real network info."""
+        return None
+
+
+@pytest.fixture
+def key_pair():
+    return create_new_key_pair()
+
+
+@pytest.fixture
+def peer_id(key_pair):
+    return ID.from_pubkey(key_pair.public_key)
+
+
+@pytest.fixture
+async def secure_conn_pair(key_pair, peer_id):
+    """Create a pair of secure connections for testing."""
+    logging.debug("Setting up secure_conn_pair")
+    client_send, server_receive = memory_stream_pair()
+    server_send, client_receive = memory_stream_pair()
+
+    client_rw = TrioStreamAdapter(client_send, client_receive)
+    server_rw = TrioStreamAdapter(server_send, server_receive)
+
+    insecure_transport = InsecureTransport(key_pair)
+
+    async def run_outbound(nursery_results):
+        with trio.move_on_after(5):
+            client_conn = await insecure_transport.secure_outbound(client_rw, peer_id)
+            logging.debug("Outbound handshake complete")
+            nursery_results["client"] = client_conn
+
+    async def run_inbound(nursery_results):
+        with trio.move_on_after(5):
+            server_conn = await insecure_transport.secure_inbound(server_rw)
+            logging.debug("Inbound handshake complete")
+            nursery_results["server"] = server_conn
+
+    nursery_results = {}
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(run_outbound, nursery_results)
+        nursery.start_soon(run_inbound, nursery_results)
+        await trio.sleep(0.1)  # Give tasks a chance to finish
+
+    client_conn = nursery_results.get("client")
+    server_conn = nursery_results.get("server")
+
+    if client_conn is None or server_conn is None:
+        raise RuntimeError("Handshake failed: client_conn or server_conn is None")
+
+    logging.debug("secure_conn_pair setup complete")
+    return client_conn, server_conn
+
+
+@pytest.fixture
+async def yamux_pair(secure_conn_pair, peer_id):
+    """Create a pair of Yamux multiplexers for testing."""
+    logging.debug("Setting up yamux_pair")
+    client_conn, server_conn = secure_conn_pair
+    client_yamux = Yamux(client_conn, peer_id, is_initiator=True)
+    server_yamux = Yamux(server_conn, peer_id, is_initiator=False)
+    async with trio.open_nursery() as nursery:
+        with trio.move_on_after(5):
+            nursery.start_soon(client_yamux.start)
+            nursery.start_soon(server_yamux.start)
+            await trio.sleep(0.1)
+            logging.debug("yamux_pair started")
+        yield client_yamux, server_yamux
+    logging.debug("yamux_pair cleanup")
+
+
+@pytest.mark.trio
+async def test_yamux_race_condition_without_locks(yamux_pair):
+    """
+    Test for race-around/interleaving in Yamux streams,when reading in
+    segments of data.
+    This launches concurrent writers/readers on both sides of a stream.
+    If there is no proper locking, the received data may be interleaved
+    or corrupted.
+
+    The test creates structured messages and verifies they are received
+    intact and in order.
+    Without proper locking, concurrent read/write operations could cause
+    data corruption
+    or message interleaving, which this test will catch.
+    """
+    client_yamux, server_yamux = yamux_pair
+    client_stream: YamuxStream = await client_yamux.open_stream()
+    server_stream: YamuxStream = await server_yamux.accept_stream()
+    MSG_COUNT = 10
+    MSG_SIZE = 256 * 1024  # At max,only DEFAULT_WINDOW_SIZE bytes can be read
+    client_msgs = [
+        f"CLIENT-MSG-{i:03d}-".encode().ljust(MSG_SIZE, b"C") for i in range(MSG_COUNT)
+    ]
+    server_msgs = [
+        f"SERVER-MSG-{i:03d}-".encode().ljust(MSG_SIZE, b"S") for i in range(MSG_COUNT)
+    ]
+    client_received = []
+    server_received = []
+
+    async def writer(stream, msgs, name):
+        """Write messages with minimal delays to encourage race conditions."""
+        for i, msg in enumerate(msgs):
+            await stream.write(msg)
+            # Yield control frequently to encourage interleaving
+            if i % 5 == 0:
+                await trio.sleep(0.005)
+
+    async def reader(stream, received, name):
+        """Read messages and store them for verification."""
+        for i in range(MSG_COUNT):
+            data = await stream.read(MSG_SIZE)
+            received.append(data)
+            if i % 3 == 0:
+                await trio.sleep(0.001)
+
+    # Running all operations concurrently
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(writer, client_stream, client_msgs, "client")
+        nursery.start_soon(writer, server_stream, server_msgs, "server")
+        nursery.start_soon(reader, client_stream, client_received, "client")
+        nursery.start_soon(reader, server_stream, server_received, "server")
+
+    assert len(client_received) == MSG_COUNT, (
+        f"Client received {len(client_received)} messages, expected {MSG_COUNT}"
+    )
+    assert len(server_received) == MSG_COUNT, (
+        f"Server received {len(server_received)} messages, expected {MSG_COUNT}"
+    )
+    assert client_received == server_msgs, (
+        "Client did not receive server messages in order or intact!"
+    )
+    assert server_received == client_msgs, (
+        "Server did not receive client messages in order or intact!"
+    )
+    for i, msg in enumerate(client_received):
+        assert len(msg) == MSG_SIZE, (
+            f"Client message {i} has wrong size: {len(msg)} != {MSG_SIZE}"
+        )
+
+    for i, msg in enumerate(server_received):
+        assert len(msg) == MSG_SIZE, (
+            f"Server message {i} has wrong size: {len(msg)} != {MSG_SIZE}"
+        )
+
+    await client_stream.close()
+    await server_stream.close()

tests/core/stream_muxer/test_yamux_interleaving_EOF.py

@@ -0,0 +1,195 @@
+import logging
+
+import pytest
+import trio
+from trio.testing import (
+    memory_stream_pair,
+)
+
+from libp2p.abc import IRawConnection
+from libp2p.crypto.ed25519 import (
+    create_new_key_pair,
+)
+from libp2p.peer.id import (
+    ID,
+)
+from libp2p.security.insecure.transport import (
+    InsecureTransport,
+)
+from libp2p.stream_muxer.exceptions import MuxedStreamEOF
+from libp2p.stream_muxer.yamux.yamux import (
+    Yamux,
+    YamuxStream,
+)
+
+
+class TrioStreamAdapter(IRawConnection):
+    """Adapter to make trio memory streams work with libp2p."""
+
+    def __init__(self, send_stream, receive_stream, is_initiator=False):
+        self.send_stream = send_stream
+        self.receive_stream = receive_stream
+        self.is_initiator = is_initiator
+
+    async def write(self, data: bytes) -> None:
+        logging.debug(f"Attempting to write {len(data)} bytes")
+        with trio.move_on_after(2):
+            await self.send_stream.send_all(data)
+
+    async def read(self, n: int | None = None) -> bytes:
+        if n is None or n <= 0:
+            raise ValueError("Reading unbounded or zero bytes not supported")
+        logging.debug(f"Attempting to read {n} bytes")
+        with trio.move_on_after(2):
+            data = await self.receive_stream.receive_some(n)
+            logging.debug(f"Read {len(data)} bytes")
+            return data
+
+    async def close(self) -> None:
+        logging.debug("Closing stream")
+        await self.send_stream.aclose()
+        await self.receive_stream.aclose()
+
+    def get_remote_address(self) -> tuple[str, int] | None:
+        """Return None since this is a test adapter without real network info."""
+        return None
+
+
+@pytest.fixture
+def key_pair():
+    return create_new_key_pair()
+
+
+@pytest.fixture
+def peer_id(key_pair):
+    return ID.from_pubkey(key_pair.public_key)
+
+
+@pytest.fixture
+async def secure_conn_pair(key_pair, peer_id):
+    """Create a pair of secure connections for testing."""
+    logging.debug("Setting up secure_conn_pair")
+    client_send, server_receive = memory_stream_pair()
+    server_send, client_receive = memory_stream_pair()
+
+    client_rw = TrioStreamAdapter(client_send, client_receive)
+    server_rw = TrioStreamAdapter(server_send, server_receive)
+
+    insecure_transport = InsecureTransport(key_pair)
+
+    async def run_outbound(nursery_results):
+        with trio.move_on_after(5):
+            client_conn = await insecure_transport.secure_outbound(client_rw, peer_id)
+            logging.debug("Outbound handshake complete")
+            nursery_results["client"] = client_conn
+
+    async def run_inbound(nursery_results):
+        with trio.move_on_after(5):
+            server_conn = await insecure_transport.secure_inbound(server_rw)
+            logging.debug("Inbound handshake complete")
+            nursery_results["server"] = server_conn
+
+    nursery_results = {}
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(run_outbound, nursery_results)
+        nursery.start_soon(run_inbound, nursery_results)
+        await trio.sleep(0.1)  # Give tasks a chance to finish
+
+    client_conn = nursery_results.get("client")
+    server_conn = nursery_results.get("server")
+
+    if client_conn is None or server_conn is None:
+        raise RuntimeError("Handshake failed: client_conn or server_conn is None")
+
+    logging.debug("secure_conn_pair setup complete")
+    return client_conn, server_conn
+
+
+@pytest.fixture
+async def yamux_pair(secure_conn_pair, peer_id):
+    """Create a pair of Yamux multiplexers for testing."""
+    logging.debug("Setting up yamux_pair")
+    client_conn, server_conn = secure_conn_pair
+    client_yamux = Yamux(client_conn, peer_id, is_initiator=True)
+    server_yamux = Yamux(server_conn, peer_id, is_initiator=False)
+    async with trio.open_nursery() as nursery:
+        with trio.move_on_after(5):
+            nursery.start_soon(client_yamux.start)
+            nursery.start_soon(server_yamux.start)
+            await trio.sleep(0.1)
+            logging.debug("yamux_pair started")
+        yield client_yamux, server_yamux
+    logging.debug("yamux_pair cleanup")
+
+
+@pytest.mark.trio
+async def test_yamux_race_condition_without_locks(yamux_pair):
+    """
+    Test for race-around/interleaving in Yamux streams,when reading till
+    EOF is being used.
+    This launches concurrent writers/readers on both sides of a stream.
+    If there is no proper locking, the received data may be interleaved
+    or corrupted.
+
+    The test creates structured messages and verifies they are received
+    intact and in order.
+    Without proper locking, concurrent read/write operations could cause
+    data corruption
+    or message interleaving, which this test will catch.
+    """
+    client_yamux, server_yamux = yamux_pair
+    client_stream: YamuxStream = await client_yamux.open_stream()
+    server_stream: YamuxStream = await server_yamux.accept_stream()
+    MSG_COUNT = 1
+    MSG_SIZE = 512 * 1024
+    client_msgs = [
+        f"CLIENT-MSG-{i:03d}-".encode().ljust(MSG_SIZE, b"C") for i in range(MSG_COUNT)
+    ]
+    server_msgs = [
+        f"SERVER-MSG-{i:03d}-".encode().ljust(MSG_SIZE, b"S") for i in range(MSG_COUNT)
+    ]
+    client_received = []
+    server_received = []
+
+    async def writer(stream, msgs, name):
+        """Write messages with minimal delays to encourage race conditions."""
+        for i, msg in enumerate(msgs):
+            await stream.write(msg)
+            # Yield control frequently to encourage interleaving
+            if i % 5 == 0:
+                await trio.sleep(0.005)
+
+    async def reader(stream, received, name):
+        """Read messages and store them for verification."""
+        try:
+            data = await stream.read()
+            if data:
+                received.append(data)
+        except MuxedStreamEOF:
+            pass
+
+    # Running all operations concurrently
+    async with trio.open_nursery() as nursery:
+        nursery.start_soon(writer, client_stream, client_msgs, "client")
+        nursery.start_soon(writer, server_stream, server_msgs, "server")
+        nursery.start_soon(reader, client_stream, client_received, "client")
+        nursery.start_soon(reader, server_stream, server_received, "server")
+
+    assert client_received == server_msgs, (
+        "Client did not receive server messages in order or intact!"
+    )
+    assert server_received == client_msgs, (
+        "Server did not receive client messages in order or intact!"
+    )
+    for i, msg in enumerate(client_received):
+        assert len(msg) == MSG_SIZE, (
+            f"Client message {i} has wrong size: {len(msg)} != {MSG_SIZE}"
+        )
+
+    for i, msg in enumerate(server_received):
+        assert len(msg) == MSG_SIZE, (
+            f"Server message {i} has wrong size: {len(msg)} != {MSG_SIZE}"
+        )
+
+    await client_stream.close()
+    await server_stream.close()

tests/discovery/mdns/test_broadcaster.py

@@ -0,0 +1,91 @@
+"""
+Unit tests for mDNS broadcaster component.
+"""
+
+from zeroconf import Zeroconf
+
+from libp2p.discovery.mdns.broadcaster import PeerBroadcaster
+from libp2p.peer.id import ID
+
+
+class TestPeerBroadcaster:
+    """Unit tests for PeerBroadcaster."""
+
+    def test_broadcaster_initialization(self):
+        """Test that broadcaster initializes correctly."""
+        zeroconf = Zeroconf()
+        service_type = "_p2p._udp.local."
+        service_name = "test-peer._p2p._udp.local."
+        peer_id = (
+            "QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN"  # String, not ID object
+        )
+        port = 8000
+
+        broadcaster = PeerBroadcaster(
+            zeroconf=zeroconf,
+            service_type=service_type,
+            service_name=service_name,
+            peer_id=peer_id,
+            port=port,
+        )
+
+        assert broadcaster.zeroconf == zeroconf
+        assert broadcaster.service_type == service_type
+        assert broadcaster.service_name == service_name
+        assert broadcaster.peer_id == peer_id
+        assert broadcaster.port == port
+
+        # Clean up
+        zeroconf.close()
+
+    def test_broadcaster_service_creation(self):
+        """Test that broadcaster creates valid service info."""
+        zeroconf = Zeroconf()
+        service_type = "_p2p._udp.local."
+        service_name = "test-peer2._p2p._udp.local."
+        peer_id_obj = ID.from_base58("QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN")
+        peer_id = str(peer_id_obj)  # Convert to string
+        port = 8000
+
+        broadcaster = PeerBroadcaster(
+            zeroconf=zeroconf,
+            service_type=service_type,
+            service_name=service_name,
+            peer_id=peer_id,
+            port=port,
+        )
+
+        # Verify service was created and registered
+        service_info = broadcaster.service_info
+        assert service_info is not None
+        assert service_info.type == service_type
+        assert service_info.name == service_name
+        assert service_info.port == port
+        assert b"id" in service_info.properties
+        assert service_info.properties[b"id"] == peer_id.encode()
+
+        # Clean up
+        zeroconf.close()
+
+    def test_broadcaster_start_stop(self):
+        """Test that broadcaster can start and stop correctly."""
+        zeroconf = Zeroconf()
+        service_type = "_p2p._udp.local."
+        service_name = "test-start-stop._p2p._udp.local."
+        peer_id_obj = ID.from_base58("QmYyQSo1c1Ym7orWxLYvCrM2EmxFTANf8wXmmE7DWjhx5N")
+        peer_id = str(peer_id_obj)  # Convert to string
+        port = 8001
+
+        broadcaster = PeerBroadcaster(
+            zeroconf=zeroconf,
+            service_type=service_type,
+            service_name=service_name,
+            peer_id=peer_id,
+            port=port,
+        )
+
+        # Service should be registered
+        assert broadcaster.service_info is not None
+
+        # Clean up
+        zeroconf.close()

tests/discovery/mdns/test_listener.py

@@ -0,0 +1,114 @@
+"""
+Unit tests for mDNS listener component.
+"""
+
+import socket
+
+from zeroconf import ServiceInfo, Zeroconf
+
+from libp2p.abc import Multiaddr
+from libp2p.discovery.mdns.listener import PeerListener
+from libp2p.peer.id import ID
+from libp2p.peer.peerstore import PeerStore
+
+
+class TestPeerListener:
+    """Unit tests for PeerListener."""
+
+    def test_listener_initialization(self):
+        """Test that listener initializes correctly."""
+        peerstore = PeerStore()
+        zeroconf = Zeroconf()
+        service_type = "_p2p._udp.local."
+        service_name = "local-peer._p2p._udp.local."
+
+        listener = PeerListener(
+            peerstore=peerstore,
+            zeroconf=zeroconf,
+            service_type=service_type,
+            service_name=service_name,
+        )
+
+        assert listener.peerstore == peerstore
+        assert listener.zeroconf == zeroconf
+        assert listener.service_type == service_type
+        assert listener.service_name == service_name
+        assert listener.discovered_services == {}
+
+        # Clean up
+        listener.stop()
+        zeroconf.close()
+
+    def test_listener_extract_peer_info_success(self):
+        """Test successful PeerInfo extraction from ServiceInfo."""
+        peerstore = PeerStore()
+        zeroconf = Zeroconf()
+
+        listener = PeerListener(
+            peerstore=peerstore,
+            zeroconf=zeroconf,
+            service_type="_p2p._udp.local.",
+            service_name="local._p2p._udp.local.",
+        )
+
+        # Create sample service info
+        sample_peer_id = ID.from_base58(
+            "QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN"
+        )
+        hostname = socket.gethostname()
+        local_ip = "192.168.1.100"
+
+        sample_service_info = ServiceInfo(
+            type_="_p2p._udp.local.",
+            name="test-peer._p2p._udp.local.",
+            port=8000,
+            properties={b"id": str(sample_peer_id).encode()},
+            server=f"{hostname}.local.",
+            addresses=[socket.inet_aton(local_ip)],
+        )
+
+        peer_info = listener._extract_peer_info(sample_service_info)
+
+        assert peer_info is not None
+        assert isinstance(peer_info.peer_id, ID)
+        assert len(peer_info.addrs) > 0
+        assert all(isinstance(addr, Multiaddr) for addr in peer_info.addrs)
+
+        # Check that protocol is TCP since we always use TCP
+        assert "/tcp/" in str(peer_info.addrs[0])
+
+        # Clean up
+        listener.stop()
+        zeroconf.close()
+
+    def test_listener_extract_peer_info_invalid_id(self):
+        """Test PeerInfo extraction fails with invalid peer ID."""
+        peerstore = PeerStore()
+        zeroconf = Zeroconf()
+
+        listener = PeerListener(
+            peerstore=peerstore,
+            zeroconf=zeroconf,
+            service_type="_p2p._udp.local.",
+            service_name="local._p2p._udp.local.",
+        )
+
+        # Create service info with invalid peer ID
+        hostname = socket.gethostname()
+        local_ip = "192.168.1.100"
+
+        service_info = ServiceInfo(
+            type_="_p2p._udp.local.",
+            name="invalid-peer._p2p._udp.local.",
+            port=8000,
+            properties={b"id": b"invalid_peer_id_format"},
+            server=f"{hostname}.local.",
+            addresses=[socket.inet_aton(local_ip)],
+        )
+
+        peer_info = listener._extract_peer_info(service_info)
+        assert peer_info is None
+
+        # Clean up
+        listener.stop()
+        zeroconf.close()

tests/discovery/mdns/test_mdns.py

@@ -0,0 +1,121 @@
+"""
+Comprehensive integration tests for mDNS discovery functionality.
+"""
+
+import socket
+
+from zeroconf import Zeroconf
+
+from libp2p.discovery.mdns.broadcaster import PeerBroadcaster
+from libp2p.discovery.mdns.listener import PeerListener
+from libp2p.peer.id import ID
+from libp2p.peer.peerstore import PeerStore
+
+
+class TestMDNSDiscovery:
+    """Comprehensive integration tests for mDNS peer discovery."""
+
+    def test_one_host_finds_another(self):
+        """Test that one host can find another host using mDNS."""
+        # Create two separate Zeroconf instances to simulate different hosts
+        host1_zeroconf = Zeroconf()
+        host2_zeroconf = Zeroconf()
+
+        try:
+            # Host 1: Set up as broadcaster (the host to be discovered)
+            host1_peer_id_obj = ID.from_base58(
+                "QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN"
+            )
+            host1_peer_id = str(host1_peer_id_obj)  # Convert to string
+            host1_broadcaster = PeerBroadcaster(
+                zeroconf=host1_zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="host1._p2p._udp.local.",
+                peer_id=host1_peer_id,
+                port=8000,
+            )
+
+            # Host 2: Set up as listener (the host that discovers others)
+            host2_peerstore = PeerStore()
+            host2_listener = PeerListener(
+                peerstore=host2_peerstore,
+                zeroconf=host2_zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="host2._p2p._udp.local.",
+            )
+
+            # Host 1 registers its service for discovery
+            host1_broadcaster.register()
+
+            # Verify that host2 discovered host1
+            assert len(host2_listener.discovered_services) > 0
+            assert "host1._p2p._udp.local." in host2_listener.discovered_services
+
+            # Verify that host1's peer info was added to host2's peerstore
+            discovered_peer_id = host2_listener.discovered_services[
+                "host1._p2p._udp.local."
+            ]
+            assert str(discovered_peer_id) == host1_peer_id
+
+            # Verify addresses were added to peerstore
+            try:
+                addrs = host2_peerstore.addrs(discovered_peer_id)
+                assert len(addrs) > 0
+                # Should be TCP since we always use TCP protocol
+                assert "/tcp/8000" in str(addrs[0])
+            except Exception:
+                # If no addresses found, the discovery didn't work properly
+                assert False, "Host1 addresses should be in Host2's peerstore"
+
+            # Clean up
+            host1_broadcaster.unregister()
+            host2_listener.stop()
+
+        finally:
+            host1_zeroconf.close()
+            host2_zeroconf.close()
+
+    def test_service_info_extraction(self):
+        """Test service info extraction functionality."""
+        peerstore = PeerStore()
+        zeroconf = Zeroconf()
+
+        try:
+            listener = PeerListener(
+                peerstore=peerstore,
+                zeroconf=zeroconf,
+                service_type="_p2p._udp.local.",
+                service_name="test-listener._p2p._udp.local.",
+            )
+
+            # Create a test service info
+            test_peer_id = ID.from_base58(
+                "QmYyQSo1c1Ym7orWxLYvCrM2EmxFTANf8wXmmE7DWjhx5N"
+            )
+            hostname = socket.gethostname()
+
+            from zeroconf import ServiceInfo
+
+            service_info = ServiceInfo(
+                type_="_p2p._udp.local.",
+                name="test-service._p2p._udp.local.",
+                port=8001,
+                properties={b"id": str(test_peer_id).encode()},
+                server=f"{hostname}.local.",
+                addresses=[socket.inet_aton("192.168.1.100")],
+            )
+
+            # Test extraction
+            peer_info = listener._extract_peer_info(service_info)
+
+            assert peer_info is not None
+            assert peer_info.peer_id == test_peer_id
+            assert len(peer_info.addrs) == 1
+            assert "/tcp/8001" in str(peer_info.addrs[0])
+
+            print("✅ Service info extraction test successful!")
+            print(f"   Extracted peer ID: {peer_info.peer_id}")
+            print(f"   Extracted addresses: {[str(addr) for addr in peer_info.addrs]}")
+
+        finally:
+            zeroconf.close()

tests/discovery/mdns/test_utils.py

@@ -0,0 +1,39 @@
+"""
+Basic unit tests for mDNS utils module.
+"""
+
+import string
+
+from libp2p.discovery.mdns.utils import stringGen
+
+
+class TestStringGen:
+    """Unit tests for stringGen function."""
+
+    def test_stringgen_default_length(self):
+        """Test stringGen with default length (63)."""
+        result = stringGen()
+
+        assert isinstance(result, str)
+        assert len(result) == 63
+
+        # Check that all characters are from the expected charset
+        charset = string.ascii_lowercase + string.digits
+        for char in result:
+            assert char in charset
+
+    def test_stringgen_custom_length(self):
+        """Test stringGen with custom lengths."""
+        # Test various lengths
+        test_lengths = [1, 5, 10, 20, 50, 100]
+
+        for length in test_lengths:
+            result = stringGen(length)
+
+            assert isinstance(result, str)
+            assert len(result) == length
+
+            # Check that all characters are from the expected charset
+            charset = string.ascii_lowercase + string.digits
+            for char in result:
+                assert char in charset

tests/utils/pubsub/utils.py

@@ -24,16 +24,22 @@ def make_pubsub_msg(
     )
 
 
-# TODO: Implement sparse connect
 async def dense_connect(hosts: Sequence[IHost]) -> None:
     await connect_some(hosts, 10)
 
 
-# FIXME: `degree` is not used at all
 async def connect_some(hosts: Sequence[IHost], degree: int) -> None:
+    """
+    Connect each host to up to 'degree' number of other hosts.
+    Creates a sparse network topology where each node has limited connections.
+    """
     for i, host in enumerate(hosts):
-        for host2 in hosts[i + 1 :]:
-            await connect(host, host2)
+        connections_made = 0
+        for j in range(i + 1, len(hosts)):
+            if connections_made >= degree:
+                break
+            await connect(host, hosts[j])
+            connections_made += 1
 
 
 async def one_to_all_connect(hosts: Sequence[IHost], central_host_index: int) -> None:

tests/utils/utils.py

@@ -0,0 +1,31 @@
+from unittest.mock import (
+    MagicMock,
+)
+
+import trio
+
+from libp2p.abc import IHost
+
+
+def create_mock_connections(count: int = 50) -> dict:
+    connections = {}
+
+    for i in range(1, count):
+        peer_id = f"peer-{i}"
+        mock_conn = MagicMock(name=f"INetConn-{i}")
+        connections[peer_id] = mock_conn
+
+    return connections
+
+
+async def run_host_forever(host: IHost, addr):
+    async with host.run([addr]):
+        await trio.sleep_forever()
+
+
+async def wait_until_listening(host, timeout=3):
+    with trio.move_on_after(timeout):
+        while not host.get_addrs():
+            await trio.sleep(0.05)
+        return
+    raise RuntimeError("Timed out waiting for host to get an address")