From 3b5c71700cf952446ed06ee67539dec02384ae13 Mon Sep 17 00:00:00 2001
From: Josh Deprez <josh.deprez@gmail.com>
Date: Sun, 21 Apr 2024 15:14:16 +1000
Subject: [PATCH] Add peer list function

---
 jrouter.yaml     |  6 ++++--
 main.go          | 33 +++++++++++++++++++++++++++++++++
 router/config.go |  3 +++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/jrouter.yaml b/jrouter.yaml
index 26d301b..a4fa3b2 100644
--- a/jrouter.yaml
+++ b/jrouter.yaml
@@ -1,10 +1,12 @@
 ethertalk:
     device: enp2s0
-    # ethernet_addr: '08:00:07:fe:dc:ba'
+    #ethernet_addr: '08:00:07:fe:dc:ba'
     zone_name: The Twilight Zone
     net_start: 100
     net_end: 100
 
 open_peering: true
 peers:
-- 192.168.86.21
\ No newline at end of file
+- 192.168.86.21
+
+#peerlist_url: http://example.com/peers.txt
\ No newline at end of file
diff --git a/main.go b/main.go
index 15f31e0..a6beaa4 100644
--- a/main.go
+++ b/main.go
@@ -17,6 +17,7 @@
 package main
 
 import (
+	"bufio"
 	"context"
 	"errors"
 	"flag"
@@ -25,9 +26,11 @@ import (
 	"log"
 	"math/rand/v2"
 	"net"
+	"net/http"
 	"os"
 	"os/signal"
 	"regexp"
+	"strings"
 	"sync"
 	"time"
 
@@ -147,6 +150,31 @@ func main() {
 	zones.Upsert(cfg.EtherTalk.NetStart, cfg.EtherTalk.ZoneName, true)
 
 	// ------------------------- Configured peer setup ------------------------
+	if cfg.PeerListURL != "" {
+		log.Printf("Fetching peer list from %s...", cfg.PeerListURL)
+		existing := len(cfg.Peers)
+		func() {
+			resp, err := http.Get(cfg.PeerListURL)
+			if err != nil {
+				log.Fatalf("Couldn't fetch peer list: %v", err)
+			}
+			defer resp.Body.Close()
+
+			sc := bufio.NewScanner(resp.Body)
+			for sc.Scan() {
+				p := strings.TrimSpace(sc.Text())
+				if p == "" {
+					continue
+				}
+				cfg.Peers = append(cfg.Peers, p)
+			}
+			if err := sc.Err(); err != nil {
+				log.Fatalf("Couldn't scan peer list response: %v", err)
+			}
+		}()
+		log.Printf("Fetched list containing %d peers", len(cfg.Peers)-existing)
+	}
+
 	for _, peerStr := range cfg.Peers {
 		if !hasPortRE.MatchString(peerStr) {
 			peerStr += ":387"
@@ -159,6 +187,11 @@ func main() {
 		}
 		log.Printf("resolved %q to %v", peerStr, raddr)
 
+		if raddr.IP.Equal(localIP) {
+			log.Printf("%v == %v == me, skipping", peerStr, raddr)
+			continue
+		}
+
 		peer := &router.Peer{
 			Config: cfg,
 			Transport: &aurp.Transport{
diff --git a/router/config.go b/router/config.go
index 6ee5d76..1b3ba4d 100644
--- a/router/config.go
+++ b/router/config.go
@@ -53,6 +53,9 @@ type Config struct {
 
 	// List of peer routers.
 	Peers []string `yaml:"peers"`
+
+	// Or a URL to fetch a list of peers from.
+	PeerListURL string `yaml:"peerlist_url"`
 }
 
 func LoadConfig(cfgPath string) (*Config, error) {