Implement Bitswap in py-libp2p

Makefile

@@ -62,7 +62,10 @@ PB = libp2p/crypto/pb/crypto.proto \
 	libp2p/relay/circuit_v2/pb/circuit.proto \
 	libp2p/relay/circuit_v2/pb/dcutr.proto \
 	libp2p/kad_dht/pb/kademlia.proto \
-	libp2p/discovery/rendezvous/pb/rendezvous.proto
+	libp2p/discovery/rendezvous/pb/rendezvous.proto \
+	libp2p/bitswap/pb/bitswap.proto \
+	libp2p/bitswap/pb/dag_pb.proto \
+	libp2p/bitswap/pb/unixfs.proto
 
 PY = $(PB:.proto=_pb2.py)
 PYI = $(PB:.proto=_pb2.pyi)

docs/examples.bitswap.rst

@@ -0,0 +1,174 @@
+Bitswap File Sharing
+====================
+
+This example demonstrates peer-to-peer file sharing using the Bitswap protocol with Merkle DAG structure.
+
+What is Bitswap?
+----------------
+
+Bitswap is a data exchange protocol that enables peers to request and share content-addressed blocks.
+Files are split into blocks, organized in a Merkle DAG (Directed Acyclic Graph), and transferred efficiently between peers.
+
+Quick Start
+-----------
+
+**Start a provider to share a file:**
+
+.. code-block:: bash
+
+    python examples/bitswap/bitswap.py --mode provider --file myfile.pdf
+
+**Download the file from another machine:**
+
+.. code-block:: bash
+
+    python examples/bitswap/bitswap.py --mode client \
+        --provider "/ip4/192.168.1.10/tcp/8000/p2p/QmXXX..." \
+        --cid "017012207b..."
+
+Usage
+-----
+
+Provider Mode
+~~~~~~~~~~~~~
+
+Share a file with other peers:
+
+.. code-block:: bash
+
+    # Share a file (auto port)
+    python bitswap.py --mode provider --file document.pdf
+
+    # Share on specific port
+    python bitswap.py --mode provider --file photo.jpg --port 8000
+
+The provider will:
+
+1. Create a Merkle DAG from the file
+2. Store all blocks in memory
+3. Display the root CID and connection command
+4. Wait for client connections
+
+Client Mode
+~~~~~~~~~~~
+
+Download a file from a provider:
+
+.. code-block:: bash
+
+    python bitswap.py --mode client \
+        --provider "/ip4/192.168.1.10/tcp/8000/p2p/QmProviderID..." \
+        --cid "01701220abc..."
+
+    # Specify output directory
+    python bitswap.py --mode client \
+        --provider "<multiaddr>" \
+        --cid "<root_cid>" \
+        --output ~/Downloads
+
+The client will:
+
+1. Connect to the provider
+2. Request blocks by CID
+3. Reconstruct the file from blocks
+4. Save to disk with original filename
+
+How It Works
+------------
+
+The implementation uses a Merkle DAG structure for all files:
+
+1. **File Chunking**: Files are split into 256KB blocks
+2. **DAG Creation**: Blocks are organized in a tree structure
+3. **Root CID**: A single identifier for the entire file
+4. **Block Exchange**: Client requests blocks, provider sends them
+5. **Reconstruction**: Client rebuilds file from blocks
+
+Example Session
+---------------
+
+Provider Output
+~~~~~~~~~~~~~~~
+
+.. code-block:: text
+
+    ======================================================================
+    PROVIDER NODE STARTING
+    ======================================================================
+    File: document.pdf
+    Size: 2.5 MB
+    Port: auto
+    ======================================================================
+    Peer ID: QmSK4bN4fDCxwvSVYvxxgHex2wob6VwzpEfpw8hc2Xxbow
+    Listening on 2 address(es):
+      /ip4/192.168.1.101/tcp/50182/p2p/QmSK4bN4fDCxwvSVYvxxgHex2wob6VwzpEfpw8hc2Xxbow
+      /ip4/127.0.0.1/tcp/50182/p2p/QmSK4bN4fDCxwvSVYvxxgHex2wob6VwzpEfpw8hc2Xxbow
+    ✓ Bitswap started
+
+    Adding file to DAG...
+      📤 completed: 100.0% (2.5 MB/2.5 MB)
+
+    ======================================================================
+    FILE READY TO SHARE!
+    ======================================================================
+    Root CID:  01701220336d0f55eac9b5536e1d5f4a5429bbc9a7343f1e1d19b7757baf76b61f4f4731
+
+    📋 COPY THIS COMMAND TO RUN CLIENT:
+    ======================================================================
+    python bitswap.py --mode client --provider "..." --cid "..."
+    ======================================================================
+
+    Provider is running. Press Ctrl+C to stop...
+
+Client Output
+~~~~~~~~~~~~~
+
+.. code-block:: text
+
+    ======================================================================
+    CLIENT NODE STARTING
+    ======================================================================
+    Provider:   /ip4/192.168.1.101/tcp/50182/p2p/QmSK4b...
+    Root CID:   01701220336d0f55eac9b5536e1d5f4a5429bbc9a7343f1e...
+    Output dir: /tmp
+    ======================================================================
+    Client Peer ID: QmTaLxNyPszMamvE7X8oYaso1eFceB8Dqjqo3v157kfioY
+    ✓ Bitswap started
+
+    Connecting to provider...
+    ✓ Connected
+
+    Fetching file...
+
+    ======================================================================
+    FETCH STATISTICS:
+    ======================================================================
+    Total blocks fetched: 12
+      ✓ 1. 01701220... (256.0 KB)
+      ✓ 2. 01551220... (256.0 KB)
+      ...
+
+    ======================================================================
+    FILE DOWNLOADED!
+    ======================================================================
+    Size: 2.5 MB
+    Filename: document.pdf (from metadata)
+    ✓ Saved to: /tmp/document.pdf
+    ======================================================================
+
+Features
+--------
+
+* **Content Addressing**: Files identified by cryptographic hash (CID)
+* **Merkle DAG Structure**: Efficient handling of files of any size
+* **Block-level Transfer**: Parallel block fetching for speed
+* **File Metadata**: Original filename preserved in DAG
+* **Resume Support**: Can request specific missing blocks
+* **Integrity Verification**: All blocks verified by CID
+
+See Also
+--------
+
+* :doc:`libp2p.bitswap` - Bitswap API documentation
+* `Bitswap Protocol Specification <https://specs.ipfs.tech/bitswap-protocol/>`_
+* :doc:`examples` - Other py-libp2p examples

docs/examples.rst

@@ -12,6 +12,7 @@ Examples
    examples.echo_quic
    examples.ping
    examples.pubsub
+   examples.bitswap
    examples.circuit_relay
    examples.kademlia
    examples.mDNS

docs/libp2p.bitswap.pb.rst

@@ -0,0 +1,37 @@
+libp2p.bitswap.pb package
+=========================
+
+Submodules
+----------
+
+libp2p.bitswap.pb.bitswap\_pb2 module
+-------------------------------------
+
+.. automodule:: libp2p.bitswap.pb.bitswap_pb2
+   :members:
+   :show-inheritance:
+   :undoc-members:
+
+libp2p.bitswap.pb.dag\_pb\_pb2 module
+-------------------------------------
+
+.. automodule:: libp2p.bitswap.pb.dag_pb_pb2
+   :members:
+   :show-inheritance:
+   :undoc-members:
+
+libp2p.bitswap.pb.unixfs\_pb2 module
+------------------------------------
+
+.. automodule:: libp2p.bitswap.pb.unixfs_pb2
+   :members:
+   :show-inheritance:
+   :undoc-members:
+
+Module contents
+---------------
+
+.. automodule:: libp2p.bitswap.pb
+   :members:
+   :show-inheritance:
+   :undoc-members: