Add support for public broadcast IP (#52)

app/config/config.go

@@ -97,6 +97,7 @@ type (
 	P2PConfig struct {
 		AlertSystemProtocolID string        `json:"alert_system_protocol_id" mapstructure:"alert_system_protocol_id"` // AlertSystemProtocolID is the protocol ID to use on the libp2p network for alert system communication
 		BootstrapPeer         string        `json:"bootstrap_peer" mapstructure:"bootstrap_peer"`                     // BootstrapPeer is the bootstrap peer for the libp2p network
+		BroadcastIP           string        `json:"broadcast_ip" mapstructure:"broadcast_ip"`                         // BroadcastIP is the public facing IP address to broadcast to other peers
 		IP                    string        `json:"ip" mapstructure:"ip"`                                             // IP is the IP address for the P2P server
 		Port                  string        `json:"port" mapstructure:"port"`                                         // Port is the port for the P2P server
 		PrivateKeyPath        string        `json:"private_key_path" mapstructure:"private_key_path"`                 // PrivateKeyPath is the path to the private key

app/config/envs/mainnet.json

@@ -65,6 +65,7 @@
   "p2p": {
     "ip": "0.0.0.0",
     "port": "9906",
+    "broadcast_ip": "",
     "alert_system_protocol_id": "/bitcoin/alert-system/1.0.0",
     "bootstrap_peer": "",
     "private_key_path": "",

app/config/envs/stn.json

@@ -67,6 +67,7 @@
     "port": "9906",
     "alert_system_protocol_id": "/bitcoin-stn/alert-system/0.0.1",
     "bootstrap_peer": "",
+    "broadcast_ip": "",
     "private_key_path": "",
     "topic_name": "bitcoin_alert_system_stn"
   },

app/config/envs/testnet.json

@@ -67,6 +67,7 @@
     "port": "9906",
     "alert_system_protocol_id": "/bitcoin-testnet/alert-system/0.0.1",
     "bootstrap_peer": "",
+    "broadcast_ip": "",
     "private_key_path": "",
     "topic_name": "bitcoin_alert_system_testnet"
   },

app/p2p/server.go

@@ -8,6 +8,8 @@ import (
 	"os"
 	"time"
 
+	maddr "github.com/multiformats/go-multiaddr"
+
 	"github.com/libp2p/go-libp2p/core/discovery"
 
 	dht "github.com/libp2p/go-libp2p-kad-dht"
@@ -73,12 +75,29 @@ func NewServer(o ServerOptions) (*Server, error) {
 		}
 	}
 
+	var extMultiAddr maddr.Multiaddr
+	if o.Config.P2P.BroadcastIP != "" {
+		extMultiAddr, err = maddr.NewMultiaddr(fmt.Sprintf("/ip4/%s/tcp/%s", o.Config.P2P.BroadcastIP, o.Config.P2P.Port))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	addressFactory := func(addrs []maddr.Multiaddr) []maddr.Multiaddr {
+		if extMultiAddr != nil {
+			// here we're appending the external facing multiaddr we created above to the addressFactory so it will be broadcast out when I connect to a bootstrap node.
+			addrs = append(addrs, extMultiAddr)
+		}
+		return addrs
+	}
+
 	// Create a new host
 	var h host.Host
 	if h, err = libp2p.New(
 		libp2p.ListenAddrStrings(fmt.Sprintf("/ip4/%s/tcp/%s", o.Config.P2P.IP, o.Config.P2P.Port)),
 		libp2p.Identity(*pk),
 		libp2p.EnableHolePunching(),
+		libp2p.AddrsFactory(addressFactory),
 	); err != nil {
 		return nil, err
 	}