🛜RescueMesh

RescueMesh is an offline-first, peer-to-peer (P2P) emergency communication system designed for disaster-prone areas where internet connectivity is non-existent.

When traditional networks fail, RescueMesh allows any group of devices (rescue teams or civilians) to communicate as long as they are connected to the same local network via Wi-Fi, a mobile hotspot, or Ethernet LAN.

❓ Why RescueMesh?

In the immediate aftermath of natural disasters, cellular towers and ISPs are often the first things to go down. This creates a "blackout" that hinders rescue efforts.

RescueMesh fills this gap by:

• Eliminating Internet Dependency: Communicates directly between devices.
• Rapid Deployment: Requires no configuration; just join the same local network and start chatting.
• Resilience: No central server means no single point of failure.

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🛠️ Technical Architecture

Peer-to-Peer Core

The system is built using the libp2p-go library. It establishes encrypted P2P connections and utilizes a Chat Room abstraction to manage group communications.

Zero-Config Discovery (mDNS)

To find other devices without an internet connection, RescueMesh uses Multicast DNS (mDNS).

mDNS resolves hostnames to IP addresses within small networks that do not have a local name server. It allows nodes to broadcast their presence and "discover" peers automatically on the same LAN.

File Structure

• 📂 /cmd/rescuemesh/main.go — The core logic for host creation and peer connection.
• 📂 /cmd/rescuemesh/logs.txt — A persistent backup of all messages received.
• 📂 /internal/p2p/host.go — Network host initialization.
• 📂 /internal/p2p/mdns.go — mDNS discovery implementation.
• 📂 /internal/p2p/pubsub.go — PubSub (GossipSub) implementation for the chat rooms.

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🚀 Installation & Usage

Step to Start the Backend

• Navigate to the library

cd RescueMesh

• Info about the Flags

• --Port — The port where your host runs..

• --same_string — Used by MDNS to discover peers; this must be the same among peers wanting to connect.

• --nick —Your display name visible to other peers.

• --room —The name of the chat room (must be the same for all peers in a group).

• Run command in another terminal/device connceted together via Wifi/Ethernet LAN to create another peer.

• PORT A:

 go run main.go --port 9000 --same_string xyz --room myroom --nick Akshay

• PORT B:

 go run main.go --port 9001 --same_string xyz --room myroom --nick Aryan

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