fix(network): encoding and decoding of peersharing peer address

[lancevincentsalera]

REASON FOR FIX

Context

• The peer client start the peersharing mini-protocol by sending MsgShareRequest to the peer server.
• The peer client receives a message via MsgSharePeers that contains PeerAddresses from the peer server.
  • PeerAddress enum contains Ipv4 and Ipv6
• The CDDL specification for peer addresses requires:
  • IPv4: An array [0, word32, portNumber]
  • IPv6: An array [1, word32, word32, word32, word32, flowInfo, scopeId, portNumber]
• The original implementation decodes the IPv4 address as raw bytes instead of u32.
• The original implementation did not include the extra fields flowInfo and scopeId for IPv6.
• The original implementation did not segment and encode IPv6 into four 32-bit words as per the CDDL.

Issue

• IPv4 Issue: The address was being decoded as raw bytes rather than as a single 32‑bit integer causing TypeMismatch. Encoding should also be tweaked as such to match the word32 in the network spec CDDL.
• IPv6 Issue: The IPv6 address was not split into four 32‑bit words, and the additional required fields—flow_info and scope_id—were missing.
• These issues led to incorrect binary representations during encoding/decoding, causing protocol mismatches.

Solution

IPv4 Encoding/Decoding:

• Encoding: Use Ipv4Addr::to_bits() to convert the IPv4 address to a 32‑bit unsigned integer (word32) instead of encoding raw bytes.
• Decoding: Read the u32 value and reconstruct the IPv4 address with Ipv4Addr::from_bits().
  IPv6 Encoding/Decoding:
• Encoding: Convert the Ipv6Addr into a 128‑bit integer using Ipv6Addr::to_bits().
• Split this 128‑bit value into four 32‑bit words (by shifting and masking).
• Append the additional fields: flow_info and scope_id (both as u32) and the port.
• Decoding: Read four u32 values, combine them into a u128 (using bit shifts), and reconstruct the IPv6 address via Ipv6Addr::from_bits().
• Read the additional u32 values for flow_info and scope_id, as well as the port.
• These changes ensure the encoded format strictly follows the CDDL.

Results

• IPv4 Addresses: Now encoded as [0, word32, portNumber] where the word32 is the IPv4 address converted via to_bits().
• IPv6 Addresses: Now encoded as [1, word0, word1, word2, word3, flowInfo, scopeId, portNumber], matching the CDDL exactly.
• The network layer now correctly interprets and reconstructs peer addresses.
• Peer discovery and overall protocol operations run as expected without mismatches.

Testing

• Unit Tests: Added tests that:
  • Encode an IPv4 address, decode it back, and verify that the resulting Ipv4Addr matches the original.
  • Encode an IPv6 address along with flow_info, scope_id, and port; then decode and verify that all fields are correctly restored.
• Utilized local pallas changes for Boros dependency and tested peersharing capabilities inside. New peers were discovered.
• Manual Debugging: Verified (via logging and hex dumps) that the encoded and decoded output now exactly matches the CDDL specification.